Design a factory for drying sliced mango at Capacity of 3000kg dried products per day

MATERIALS OVERVIEW

Overview of raw material

Mango is a tropical fruit scientifically known as Mangifera indica, belonging to the Anacardiaceae family Mangifera has up to 41 species, can be found scattered throughout

Southeast Asia, of which only mango is the most widely grown Since the 16th century, the Portuguese introduced mangoes to South Africa and Brazil and today mangoes are widely available around the world In Vietnam, mango is grown mainly in the Mekong Delta, Khanh Hoa

The trunk of the mango tree is about 10-15m high, long-lived After 6-8 years from planting mango will flower, usually in December to March of the solar calendar Mango flowers are small, pinkish-white, bloom in clusters, mostly male and hermaphroditic flowers

Mango fruit is round to slightly elongated, yellow to red when ripe, mildly sweet and fragrant Mango is a light-loving, water-tolerant plant, suitable for light soils with poor fertility, the amount of nitrogen and potassium significantly affects the quality of the fruit obtained In case of lack of potassium for small fruit, excess potassium cracked fruit, more protein for less fruit

The mango fruit is composed of three main parts:

- Mango peel: is a thin, tough skin, initially green, when ripe, it turns yellow, greenish yellow or pinkish depending on the variety

- Mango flesh: contains a lot of water, fibrous or no fiber The flesh of the fruit is light yellow to dark yellow when ripe The fruit pulp is the part recovered to make mango products

- Mango seed: Each fruit has a seed covered by a fleshy layer When a mango is ripe, the seed is often attached to the flesh

Mango varieties in Vietnam are very diverse, harvested in April (mango in the South) and July (mango in Cam Ranh, Yen Chau) Some mango varieties are popularly grown in Vietnam such as Hoa Loc mango, Cat Chu mango, Tuong mango, Thanh ca mango, etc But in this report, we choose Cat Chu mango with some special characteristics as follows

It is called Cat Chu because the mango fruit's head, where the stem is, comes from Dong Thap The quality of the fruit is delicious, the flesh is sweet, the taste is slightly sour, the fruit is slightly round, the average fruit weight is 250-350g, the fruit skin is thin when ripe, the color is red like cinnabar Mango fruit has thick rice, small seeds, low fiber, almost no fiber and very delicious quality, very popular in the northern market This is a very concentrated flowering and easy fruiting mango variety, very high yield high Fruiting time in December or earlier 3-4 months before

1.1.3 Chemical composition of mango fruit

Mango contains a large amount of water in mango, in addition, the chemical composition of mango also contains sugar, acid, carotene, vitamins, especially vitamin B, vitamin C Vitamin A is abundant when the fruit is ripe and vitamin C has many times when its unripe

Table 1 1: Chemical composition of mango in 100g edible Ingredients Amount Ingredients Amount

The main organic acids in mango are citric acid and a few malic acid, oxalic acid Mango contains non-replaceable amino acids such as tryptophan 0.008%, lysine 0.041%, leucine 0.031%, histidine 0.012%, valine 0.026% , isoleusine 0.018%, Compounds belonging to 3 groups of car-3-ene, α-capoene and ethyldodecanoate determine the scent of mango, these compounds are volatile during processing

The USDA Nutrient Database (National Nutrient Database for Standard Reference) reported the value of vitamins and nutrients in 100g of edible mangoes, showing that eating mangoes can regularly provide the dietary needs of these vitamins and nutrients (WHO/FAO, 2003)

The chemical composition of mango varies by variety, location, season, ripeness, growing conditions and the nurture

+Lowers cholesterol, stabilizes blood pressure, protects the heart: the high content of vitamin C, pectin and fiber found in mangoes have the effect of reducing serum cholesterol levels, especially improving the condition dyslipidemia in the blood Mangoes are high in potassium which can also help reduce high blood pressure

+Prevent cancer: The antioxidant compounds in mango are isoquercitrin, quercetin, fisetin, astragalin, methylgallate, gallic acid as well as other enzymes These compounds have protective effects against bowel cancer, prostate cancer and leukemia

+Alkalize the body: a small amount of citric acid and tartaric acid are found in mangoes, which have the effect of maintaining and storing alkalinity for the body

+Improves digestion: The fiber in mangoes also helps with digestion and excretion People with constipation, diarrhea, frequent digestive disorders and dysentery can look to mango because it is a good remedy for the above diseases

+Mango leaves are good for people with diabetes

+In addition, mango also has the ability to: prevent aging, enhance brain power, good for anemia, protect the liver, green mango helps increase iron and calcium absorption in food, good for morning sickness However, eating less ripe mangoes is laxative, eating a lot will cause diarrhea, irritability, heat rash, boils

When the mango reaches its maximum size, the rind turns yellow and around a thin layer of chalk begins to harvest Harvest time depends on the variety, usually from April to June, the South is earlier

There are many methods of preserving mangoes after harvesting Store in cold conditions 7 – 10°C, humidity 85 – 90% for 1 month Preserve by adjusting the atmosphere, store in PE bags 0.05 - 0.08mm thick to cover individual mangoes and store at 10°C for 3 weeks, then unpack and store at 22°C for 1 week In addition, mangoes can be preserved with chitosan solution very effectively.

Extra ingredients

Water used in fruit and vegetable processing technology must meet the following requirements:

Water must be clear, colorless, tasteless and free from pathogenic microorganisms Water must satisfy the criteria of hardness, alkalinity, oxidation, and microbiology

Water used in fruit and vegetable processing technology must be soft, with a temporary hardness of about 0.7mg calcium equivalent/liter, permanent hardness of about 0.4 - 0.7 mg equivalent calcium/liter

Using sucrose, white sugar crystals, relatively uniform size, loose, dry, no lumps, no strange taste, when mixed in water, a transparent solution is obtained

During processing, people have added sugar for the purpose of adjusting the taste and increasing the sensory value of the product, while also serving as a preservative Because of the high concentration of sugar, it binds tightly to water, reducing the water activity of the product significantly, making it impossible for microorganisms to grow On the other hand, with high sugar concentration, creating osmotic pressure inhibits microbial growth

In the drinking water industry, people often use organic acids such as citric acid, ascorbic acid, etc to catalyze the hydrolysis of sucrose to create an inverse sugar syrup solution Standards of raw acids used in food production are specified according to TCVN 5561-1991 according to table 1.2 below

Table 1 2: Sensory parameters of citric acid

Colorless crystals or white powder without lumps For grade 1 citric acid allowing a slight yellow tinge, the citric acid solution in

Distilled water with a mass concentration of 20g/liter must be transparent

Taste Sour, no strange taste

Odor Acid solution in distilled water 20g/liter with no odor

Mechanical impurities Do not allow

Potassium thiosulfate is a colorless crystalline compound in the hydrohydrate form, used as an antioxidant, preservative, preventing the browning reaction of the product, making the product better

NaHSO3 substances are substances that inhibit the enzyme phenolase However, handling in solution is easier to control, it is possible that these substances will give the product a strange taste, whiten the natural color of the fruit, and be corrosive to metals In addition, it is toxic and destroys vitamin B1 For mango powder products, the residual sulfite content is negligible because the content is very low and because it is destroyed during the drying process In food, in the presence of aldehydes or acetone, it will react with sulfites or SO2 and lose its inhibitory effect on the enzyme phenolase

Therefore, when used, an excess of sulfide salts must be used to ensure the inhibition of enzyme activity SO2, H2SO3 gas or its salts (bisulfite - K, Na) are very strong inhibitors of Melanoidin coloration reaction.

Introduction about dried mango slices product

Dried mango slices are thin slices, light yellow in color, mildly sweet and sour, with a characteristic aroma of mango The moisture content of the product ranges from 14–18% Dried mango with delicious taste and high nutritional value is a popular and appreciated product not only in Vietnam but also has a significant position in international markets (Japan, China,…) Products can also be used as gifts for family members, partners on special occasions of the year

Figure 1 3: Dried slices mango product 1.3.2 Sensory

Sensory parameters of sliced dried mango products are shown in table 1.3

Table 1 3: Sensory value of sliced dried mango

Status Harmonious flexibility and toughness

Color Light yellow, less dark

Odor Characteristic aroma of ripe mango

Taste The harmonious sweet and sour taste of ripe mango

Microbiological criteria according to Decision No 46/2007/QD-BYT dated December 19, 2007 are shown in Table 1.4

Table 1 4: Microbiological parameters of sliced dried

Order Target name Unit Maximum levels

6 Total number of yeast – mold spores

- Size of slices of dried mango (cm): 8.3 - 8.7 long; width 2.6 – 3.3; 0.3 - 0.6 thickness

- Check the outer shape and tightness of the package

- Determination of physical parameters: humidity, temperature,

1.3.5 Nutritional value of the product

The product nutritional value of sliced dried mango is shown in table 1.5

Table 1 5: Product nutritional value in 100g of product

Ingredients Nutritional value Ingredients Nutritional value

FACTORY DESIGN AND PRODUCTION PROCESS SELECTION

Factory construction site

The location of the factory is very important, to ensure that the factory works well during the production period and the factory is built to satisfy the following conditions:

- Near the national electricity grid

Tan Huong Industrial Park, Chau Thanh District, Tien Giang Province is 12 km from

My Tho City, 50 km from Ho Chi Minh City, next to National Highway 1A and the Ho Chi Minh City - Trung Luong Expressway With the border with the above-mentioned southwestern provinces, it is a favorable condition to satisfy the demand for supplying raw materials, an essential issue when build a factory

Table 2 1: Information about Tan Huong Industrial Park Industrial park name Tan Huong

Area available for rent 1.02 ha

The location of the factory is very important, to ensure that the factory works well during the production period and the factory is built to satisfy the following conditions: near the source of raw materials, near the national power grid, near the river lakes to take advantage of water sources, as well as climatic conditions: temperature, humidity, wind direction must be appropriate

Tien Giang is located 70 km south of Ho Chi Minh City and 90 km north of Can Tho city The North and the Northeast are bordered by Long An and Ho Chi Minh City Ho Chi Minh City, the West borders Dong Thap, the South borders Ben Tre and Vinh Long, the East borders the East Sea

Tan Huong Industrial Park, Chau Thanh District, Tien Giang Province is 12 km from

My Tho City, 50 km from Ho Chi Minh City, next to National Highway 1A and the Ho Chi Minh City - Trung Luong Expressway With the border with the above-mentioned southwestern provinces, it is a favorable condition to satisfy the demand for supplying raw materials, an essential issue when you want to build a factory

- The climate is tropical monsoon, divided into 2 distinct seasons: the rainy season and the dry season

- Main wind direction: Southwest - Northeast

- The average temperature of the year is 28 o C, the lowest temperature of the year is 26 o C, the temperature difference between months is not large, about 4 o C

2.1.2 Source of raw materials and energy

Mango is commonly grown in 59/63 provinces/cities of Vietnam The total area of mango nationwide in 2013 was about 87000 ha, of which the area for fruiting was 68,100 ha and the output was 969063 tons, the average yield was 14.23 tons/ha The Mekong Delta is the largest mango growing region in the country with an area of 41,800 hectares of mango cultivation and an output of 427268 tons (accounting for 43% of the national output) The Mekong Delta has four largest mango growing provinces, including Dong Thap province with an area of 9,200 hectares (accounting for 22% of mango growing area in the Mekong Delta), Tien Giang with 4894 hectares, An Giang with 4464 hectares, and Vinh Long with 4857 hectares The area and production of these four provinces account for 72.8% of the planted area and 72.7% of the mango production of the whole region With the abundance of raw materials mentioned above, it is suitable for the goal of building a factory here

For a vegetable factory, it needs to consume a large amount of electricity, mainly used for thermal processes and transportation processes in production and lighting and living equipment, etc

The electricity grid in Tien Giang is invested quite synchronously, ensuring timely response to the requirements of production and business services of enterprises

In the factory, a separate transformer station must be installed to take from the high- voltage line of the common power supply network in the area

In addition, to ensure continuous production, the factory also needs to be equipped with a backup generator

In the production process of the factory, steam is used for many purposes such as: concentrating, drying, etc., including heating water for domestic use Therefore, the plant uses gas supplied from its own boiler The steam pressure needed in the plant depends on the technology requirements, which is usually from 3 at to 13 at

Boilers use fuel as DO (Diesel Oil) oil, FO (Fuel Oil or also called Mazut Oil) oil, These types are supplied from petrol stations of the province…

➢ Water supply and water treatment problem

Currently, the province has 13 surface water extraction plants and many borehole stations to exploit underground water, supplying urban areas with a total capacity of 160600m 3 /day - night, of which surface water accounts for 73.35%, groundwater accounts for 26.65%

The plant uses water from the water supply plant of Tien Giang province The water demand of the plant is very large and the purpose of use is also different Therefore, it is necessary to have an appropriate water treatment regime so as not to affect the quality of finished products and the health of workers by chemical methods, water softening with ion exchange resins, etc

This is a food processing factory, so the wastewater mainly contains organic substances, which are the environment for microorganisms to grow, making it easy to infect tools, equipment and raw materials entering the factory, which will greatly affect the health of the environment, finished product quality All production wastewater and domestic wastewater are treated by the enterprise to the minimum standard of water level C before

14 being discharged into the common wastewater system

The scrap from the factory should be treated to avoid polluting the working environment as well as the surrounding environment With the mango as the raw material, the scraps from them can all be used as microbial fertilizers, Therefore, these scraps can be sold to other factories, both hygienic and functional, economy

The factory is located in Tan Huong industrial zone with convenient traffic in product consumption, science and technology absorption Chau Thanh district has convenient waterway and road traffic Provincial road 827 and National Highway 50 shortcut are the main external transport axis of the district connecting economic regions together In addition, it is also possible to go through National Highway 1A and Ho Chi Minh City - Trung Luong Expressway By waterway, there are wharves and barges of about 500-600 tons to transport goods from the industrial park to My Tho Port and Hiep Phuoc Port

Workers are mainly recruited locally to reduce the cost of building worker dormitories Most of the recruited workers have an education level from 12th grade, when they learn through the equipment operation training course and other activities, they will definitely create a team of skilled workers, ensuring the factory's good operation

Management scientific and technical staff: with staff with many years of experience in addition, the factory will receive engineers from universities across the country and be trained to grasp the progress and new scientific and technical achievements of advanced countries in the world, this is the core force of the factory

The cooperation between the factory and other factories in terms of economics and

15 technology and the integration will increase the common use of power, water, steam, transportation, and welfare facilities Collectively and public service the problem of quick consumption of products and waste products will have the effect of reducing construction time, reducing investment capital and lowering product costs Must cooperate closely with the agricultural sector to harvest at the right time, at the right maturity age suitable for each type of plant variety in each specialized farming area in the locality In addition, the factory must have technical staff to support farmers in guiding techniques for planting, caring for and harvesting agricultural products in order to improve the quality of input materials

In order to continue to develop the raw material area and create a solid foothold, the factory needs to have signed and joint venture activities Accordingly, it will provide capital directly to farmer households to ensure a stable material area, plant according to the plan and avoid local redundancy

Technological process

2.2.1 Flowchart of the production process of dried mango slices

Figure 2 1: Flowchart of the technological process of dried mango slices

Type of raw materials: The raw material for the production of mango powder is Hoa Loc mango Mango has large fruit, fruit weight 400 - 600g

+ The fruit must be fresh, not crushed, free from pests and diseases and of appropriate ripeness

+ Using mango with technical ripeness, yellow skin, soft fruit flesh, if the mango is still green when imported, it is necessary to proceed with ripe vinegar

+ Preservation of fresh fruit at normal temperature using fungicides, microorganisms and insects or by fumigation with SO2 or other methods of changing the composition of the storage medium This technology can be preserved for 15 - 16 days

+ Selecting: remove unqualified fruits such as: green mangoes, pests, mold yeast, crushed, rotten

+ Sorting: to divide and select fruits with suitable color, integrity and ripeness for processing

+ Raw mangoes are put on the conveyor, workers standing on both sides of the conveyor will observe and select unqualified fruits to go out

+ Fruit is intact, less damaged

+ Medium ripeness, not too raw or overcooked

Helping remove dirt, garbage and impurities on the surface of the fruit, cleans the raw materials and also reduces the amount of microorganisms in the outer shell of the material, pesticide residues and chemicals

Method: First, mango is soaked in water with Ca(OCl)2 at a concentration of 5mg/l for 5 minutes It is then cleaned by an air blower After soaking, rinse the mango with clean water About every 2 hours change the washing water

Raw materials after washing must be clean, the rate of crushing is low

2.2.2.4 Peel, remove seeds, cut into pieces

+ Remove unusable parts for processing (mangoes peels/seeds) to increase recovery efficiency

+ Create mango slices of uniform and moderate size, creating favorable conditions for the next process

+ Workers peel, remove seeds, slice mangoes with stainless steel knives

+ The usage norm of raw mangoes after peeling and sliced: the proportion of mango seeds 18.48%, skin 14.4% and flesh 67.12% The slice thickness is selected appropriately from 1.6 1.9 cm, width from 3.5 4 cm

The cut must be sharp, not crushed, few parts are discarded, so the cutter part is the most important part, the knife must be sharp, made of stainless steel without rust

+ Storage: blanching will reduce the density of microorganisms on raw materials, contribute to prolonging the shelf life of the product

+ Finishing: Suspends the biochemical process of the material, so that the color of the material does not deteriorate or change only very little

+ The blanching process is carried out in a conveyor blanching device

+ Raw materials after going through the process of peeling, removing seeds, and slicing will be brought to the end of the conveyor, used by workers to store containers and then poured into the conveyor belt of the blanching device At the end of the blanching process, at the end of the device there will be a container to take to the next device

+ Sugar solution with high concentration increases the osmotic pressure to separate part of the water in the material out

+ High sugar concentration inhibits some microorganisms in raw materials

+ After blanching, the fruit pulp is soaked in sugar solution for 2 hours The ratio of raw materials and soaking solution is 1:2.5

+ The soaked sugar water solution can be reused for the 3rd time to reduce production costs

+ Wash the sugar solution remaining on the mango slices, which is convenient for the drying process

+ Reduces the bad coloration of the product

After soaking, the mangoes are put through an automatic washing machine with a conveyor belt, then taken out to dry

+ Remove moisture from raw materials to complete the product

+ Increase the shelf life of the product

+ When the mango is dry, the moisture is about 15%, then stop drying

+ Drying time is about 10 hours, temperature 65℃

Cooling the product to balance the moisture of the product before packing and to prevent moisture from condensing in the package when hot packing the product

After drying, the mango is cooled down naturally on the conveyor belt, combined with inspection to remove unsatisfactory components such as burnt, broken, cracked Workers are arranged on both sides of the conveyor to perform

The dried product must be uniform, least burnt, cracked, delicious taste, eye-catching color The products have color looked fresh and flavor kept nearly natural

+ Create sensory value for the product

+ Convenience in the stages of distribution and transportation

+ Packaging materials: Vacuum pakaging must ensure hermetic, not absorb moisture, prevent air well, easy to seal by heat, easy to print labels, etc

+ The packaging used is an inner packaging made of PE plastic, with a thickness of about 65 - 70 àm

+ After packaging, the product is stored at room temperature, ensuring coolness

CALCULATION DESIGN OF DRYING SYSTEM

Factory production plan

Assuming the factory operates continuously 3 shifts (8 hours/shift) per day, only off production on holidays, Tet and October to maintain and repair machinery and equipment due to raw material sources to preserve maintenance and repair of machinery and equipment due to the low source of mango material this month

- The number of days in 2021: 365 days

- Number of days off to maintain machinery and equipment: 31 days

- Number of holidays for New Year, Lunar New Year (8 days), 10/3, 30/4, 1/5, 2/9:

- Number of Sundays in a year (except 4 Sundays in February): 44 days

- Number of production shifts 277 × 3 = 831 (shifts)

Material harvesting chart

With the growing scientific and technical conditions today, the care of grafting are different varieties to create new varieties, application of flower treatment measures, and results are not only in the right season but also in the off season, then this is a commodity that can be earned almost all year round in both the North and the South

Table 3 1: Raw material harvesting chart

Table 3 3: Number of days, number of shifts, number of production hours in the year

Material balance for main material

The formula for calculating the volume of material coming out at each stage:

Gnv: The nitial quantity of mango of the n th stage

Gnr: Amount of product formed in the n th stage xn: Loss of the nth stage compared with the n th stage – 1

The formula for calculating the volume of materials entering each stage is:

Material loss at each stage:

3.3.1 Material balance for sliced dried mango products

The finished product of dried mango slices with the yield is:

G = 125 kg of product / h = 1000 kg of product / shift = 3000 kg of product/day

Table 3 5: Loss rate of sliced dried mango products

4 Peel, remove seeds, cut into pieces 33

Amount of material coming out of packaging stage:

G10r = G = 125 (kg/h) Amount of materials entering the packaging stage:

Amount of material loss in the packaging stage:

Amount of material coming out of the cooling and sorting process:

G9r = G10v = 125.63 (kg/h) Amount of materials entering the cooling and sorting stage:

Material loss during cooling and sorting stage:

Amount of mango material coming out of drying stage;

G8r = G9xv = 126.26 (kg/h) The moisture content of the raw materials entering the drying process is: W1 = 80%

The moisture content of the raw materials coming out of the drying process is: W2 15%

Moisture balance equation for input materials:

G8v1: is the amount of mango material entering the drying process with the moisture content of the material being W1

G8v2: is the amount of mango material entering the drying process with the moisture content of the material being W2

Amount of material entering the drying process (including loss):

Amount of moisture removed during drying:

∆G = G8v1 – G8v2 = 542.05 – 127.54 = 414.54 (kg/h) Amount of material loss in drying process:

Amount of ingredients coming out of the rinsing and drying stage:

G7r = G8v = 542.05 (kg/h) Amount of ingredients going into the rinsing and drying stage:

Material loss during rinsing and drying:

Amount of ingredients going out the sugar soaking stage:

G6r = G7v = 544.77 (kg/h) Amount of ingredients going into the sugar soaking stage:

Amount of materials lost in the process of soaking sugar solution:

Amount of material coming out of the blanching stage:

G5r = G6v = 550.27 (kg/h) Amount of materials entering the blanching stage:

➢ Peel, remove seeds, cut into pieces

The amount of ingredients coming out of the peeling, seeding, and cutting stages:

G4r = G5v = 555.83 (kg/h) The amount of ingredients going into the peeling, seeding, and cutting stages:

The amount of material lost in the process of peeling, removing seeds, cutting pieces:

Amount of material coming out of the washing stage:

G3r = G4v = 829.60 (kg/h) Amount of ingredients entering the washing stage:

Amount of material lost in the washing process:

The amount of material that goes out of the selection and sorting stage:

G2r = G3v = 830.43 (kg/h) Amount of materials going into the selection and classification stage:

Amount of materials lost in the selection and classification stage:

Amount of ingredients coming out of the incubation:

G1r = G2v = 847.38 (kg/h) Amount of ingredients going into the incubation:

Amount of materials lost in the incubation:

➢ Calculate the amount of auxiliary ingredients

+ Choose the ratio of mango ingredients and soaking solution to 1: 2.5 Productivity of the soaking process: G6v = 550.27 (kg/h)

Mdd = MK2SO3 + Macid ascorbic + Msiro = 0.03 × Mddn + 0.05 × Mddn + Mddn

Amount of Potassium Thiosulfate needed:

MK2SO3 = 1375.68 × 0.03 = 41.27 (kg/h) Amount of ascorbic acid needed:

 Amount of syrup needed in 1 shift: Msyrup = 1375.68 – 41.27 – 68.78 = 1265.63 (kg/h)

Amount of sugar and water needed to cook 45% syrup:

+Assuming the amount of syrup in 1 shift is constant, the syrup is re-cooked in each shift

+The sweetness of Cat Chu mango has the lowest value about 15 - 19%, while Cat Hoa Loc mango has the highest sweetness from 19 - 21% In order sliced dried Cat Chu mango to have natural sweetness, we need to add 4% sugar per 1 kg of mango to the initial syrup of each shift per hour for the product have a natural sweetness

+ Amount of added sugar: Mdbs = Md1 × 4% = 569.53 × 4% = 22.78 (kg/h)

 Total sugar needed for 1 production shift:

Md = Mdbs + Md1 = 569.53 + 22.78 = 592.31 (kg/shift)

 Amount of water: Mn = Msiro – Md = 1265.63 – 592.31 = 673.32 (kg/shift)

Due to the 5% water loss in the syrup cooking process, the actual amount of water required for 1 production shift is:

0.95 = 708.76 (kg/shift) + Calculate the amount of packaging:

Use PE packaging (LDPE type) with density 0.91 - 0.925 g/cm3

Product weight per pack contains: 500 (g product/bag)

Amount of materials entering the packaging stage:

G10v = 125.63 (kg/h) Number of packages to use:

Select the packaging loss in this stage to be 2%, the actual amount of packaging used;

Table 3 6: Material balance summary table for main materials

4 Peel, remove seeds, cut into pieces

Calculation of heat for drying equipment

3.4.1 Dried mango slices production line

− Amount of ingredients to be dried: G8v = 542.22 (kg/h) [Table 4.6]

− Allowable drying temperature: t1 = 65 0 C, so that P1bh = 0.255(at)

− Assume the outlet temperature: t2 = 35 0 C, so that P2bh = 0.0573(at)

− P is the overall pressure of the air P = 1.033 (at)

Figure 3 1: Diagram of ideal drying sliced 3.4.2 Calculate the parameters of the air before entering the calorifer

The state of the outdoor air where the drying equipment is located in Tien Giang, we choose the temperature as: t0 = 26 0 C, moisture: φ = 78% [31]

So look up the table we have: Pbh = 0.0345 (at) [32]

The moisture content of the air is calculated according to the following formula: x 0 =0.622 × φ 0 × P bh

With φ0 is the humidity of the air before entering Calorife: φ0 = 78%

𝑃 is the overall pressure of the air, P = 1,033 (at) [32]

The heat content of humid air before passing calorifer:

Ckkk is the specific heat capacity of dry air, Ckkk = 1 (kJ/kg 0 C)

Ch is the specific heat of water vapor, Ch = 1.97 (kJ/kg 0 C) r0 is the heat of vaporization of water, r0 = 2493 (kJ/kg) [33]

Replace in (II), we have:

3.4.3 Parameters of the air when passing the calorifer before entering the dryer

Select drying temperature: t1 = 65 0 C, so that P1bh = 0.255 (at) [32]

When it passes through the calorifer, the air changes only its temperature, but not the moisture content: x1 = x0 = 0.017 (kg/kgkkk) [34]

Specific heat of the air at this moment:

Relative humidity of the air: φ 1 = x 1 × P (0.622 × x 1 ) × P 1bh [31]

Choose the temperature out of Calorife to be t1 = 65 0 C, so Pbh = 0.255 (at) [32] φ 1 = 0.017 × 1.033 (0.622 + 0.017) × 0.255 = 10.78%

3.4.4 Parameters of air after drying

Choose the temperature when leaving the dryer: t2 5 0 C So, P2bh = 0.0573 (at)

Since it is a theoretical drying process, the specific heat of the air does not change during the drying process: I1 = I2 = 109.56 (kJ/kgkkk) [34]

Moisture content of the air: x kk = I 2 − t 1

Humidity of the air: φ kk = x kk × P

Moisture content of drying agent: x 2 = I 2 − t 2

Calculate the dew point temperature:

0.622+0.03= 0.0475 (at) Based on table I.251 [32], we get: ts = 31.5

Because ∆t ∈ [3, 5], so our choice t2 = 35 0 C is appropriate

3.4.5 Specific amount of dry air consumed to evaporate 1kg of moisture l = 1 x 2 − x 0 = 1

3.4.6 Total amount of dry air required for drying

U is the amount of moisture that needs to be evaporated in 1 hour during the drying process

According to section 3.2.3 we have: U = ∆G = 414.51 (kg/h)

The amount of heat required to evaporate 1kg of moisture: q 1 = I 1 − I 0 x 2 − x 0 9.56 − 69.25

Total heat required for moisture evaporation:

The amount of heat required to heating the drying material

G is the amount of starting material put into drying, G8v = 542.05 (kg/h)

C1 is the specific heat capacity of the drying material, C1 = 3.58 (kJ/kg 0 C)

[35] t0 is the initial temperature of the drying material, t0 = 26 0 C ttb is the heating temperature that allows the material to dry: t tb =t 1 + t 2

Heat loss carried out by the drying material:

G8r is amount of material after drying G8r = 126.26 (kg/h) θ1 is the initial temperature of the material to be dried, θ1 = t0 = 26 0 C θ2 is the outlet temperature of the drying material, assuming the material temperature is taken from the temperature of the agent leaving the dryer θ2

Cvl is the specific heat capacity of the moist material to be determined

Cvk is the specific heat of dried mango, Cvk = 1.55 (kJ/kg 0 C) [35]

Ca is the specific heat of moisture (water), Ca = 4.18 (kJ/kg 0 C) [32] So: Cvl = 1.55 × (1 – 0.15) + 4.18 × 0.15 = 1.94 (kJ/kg 0 C)

Heat loss to the environment: Qmt = 5% × Q1

Q3 = Qvl + Qmt = 5878.67 + 64265.01 = 70143.68 (kJ/h) Moisture temperature of the drying material brought in:

Q4 = U × θ1 × Ca = 414.51 × 26 × 4.18 = 45048.95 (kJ/h) The amount of heat required to supply calorifer:

= 1285300.17 + 46572.94 + 70143.68 - 45048.95 = 1356967.84 (kJ/h) Amount of saturated steam used for the dryer:

With: r is the latent heat of vaporization of saturated steam at 120 0 C r = 2203.7 (kJ/kg)

CALCULATION AND DEVICE SELECTION

Main device calculation

Air is initially introduced into the calorife, where the air receives indirect heat from the saturated steam through the wall of the heat exchanger tube The steam goes in the tube, the air goes out the tube At calorife, after receiving the required drying temperature, the hot air entering the drying room comes in contact with the drying material (mango) providing heat for the steam in the mango to evaporate out

During the drying process, the air moves at a high speed, so a part of the mango will be dragged with the air out of the drying room To recover exhaust gases and mangoes, a cyclone is placed in the hot air outlet pipe The exhaust gas after leaving the drying room enters the cyclone to separate the mango and clean it Then a part of the exhaust gas is sucked by the fan into the air duct to be discharged into the air Part of the air for recirculation mixes with the new air to form a gas mixture that is pushed into the calorife by the fan This gas mixture is heated to the required temperature and then enters the drying room to continue the drying process The re-drying process continues

The initial drying material with high moisture content is brought into the drying room through conveyors by means of a material direction device The drying material moves on the conveyor belt in the opposite direction to the direction of hot air movement and receives heat directly from the hot air mixture to perform the dehumidification process

After drying, the dry material is put into the trough and taken out

4.1.1 Volume of air a) Specific volume of air entering the dryer: v 1 = R × T 1 p − φ 1 × P 1bh ( m 3 kgkkk)

Substituting the number in we have: v 1 = R × T 1 p − φ 1 × P 1bh = 287 × 338

(1.033 − 0.1078 × 0.255) × 9.81 × 10 4 = 0.98 (m 3 /kg 𝑘𝑘𝑘 ) b) Volume of air entering the drying room:

V1 = L × v1 = 31884.11 × 0.98 = 31246.43 (m 3 /h) c) The specific volume of air leaving the drying room is: v 2 = R × T 2 p − φ 2 × P 2bh (m 3 /𝑘𝑔 𝑘𝑘𝑘 )

(1.033 − 0.8295 × 0.0573) × 9.81 × 10 4 = 0.91 (m 3 /kg 𝑘𝑘𝑘 ) d) Volume of air leaving the drying room:

V2 = L × v2 = 31884.11 × 0.91 = 29014.54 (m 3 /h) e) Average volume of air in the drying room:

Conveyor type drying equipment consists of a rectangular room in which one or several conveyor belts are moved by rotating drums, which rest on rollers to prevent sagging Conveyor belts are made of cotton yarn impregnated with rubber , steel plate or metal mesh, the air is heated in the caroifer The drying material is contained in the feed hopper, which is rolled between the two rollers to enter the top conveyor If the equipment has a conveyor, the drying does not Because the material layer is not disturbed, the equipment with multiple conveyor belts is more widely used In this type, the material from the upper belt moves to the top of the device and falls to the lower belt moving in the opposite direction .When the end of the last tape is reached, the dry material is poured into the dispensing compartment

Hot air goes against the direction of movement of the ice In order for the drying process to be good, the air is allowed to move at a great speed, about 3m/s, while the ice moves at a speed of 0.12 m/s

Br: Loading Layer Width (m) h: Mango layer thickness (m) Let h = 0.1 (m) ω: Loading speed, choose ω = 24 m/h ρ: specific gravity of mango, ρ = 700 kg/m 3

Productivity of the drying process

0.1×24×700= 0.32 (m) The actual width of the conveyor is:

B tt =B r η with η is the correction difference

Lb: conveyor length, m (one side length) ls: extra length, choose ls = 1.2 (m)

Conveyor uses only one chain, so we choose the length of a conveyor belt to be 4m, so the number of conveyor belts is 3 Diameter of conveyor belt d = 0.3 m

4.1.2 Choose the material for the drying room

− Drying room is built of brick:

− Wall thickness 0.22 (m), we have: o Brick thickness 0.2 (m) o Two layers of mortar on both sides 0.01 (m)

− The ceiling of the room is made of reinforced concrete with:

The door of the drying room is made of thin aluminum sheet, the middle layer has a thickness of 0.01 m

Two layers of aluminum 0.015 (m) each

Working length of drying room:

Lph = 4 + 2 × 0.6= 5.2 m Working height of drying room:

Hph = 0.3 + 0.1 × 3 + 0.2× 4 = 2 ( m ) Working width of drying room:

So the size of the drying room including the wall is:

4.1.3 Air velocity and air movement in the drying room a) Velocity of the air in the drying room: ω kk = V tb

Re: is the Reynolds constant that characterizes the motion of the stream ltđ: is the equivalent diameter: l tđ =2 × H ph × R ph

Average temperature of the air in the drying room: t tb =t 1 + t 2

From this average temperature, we can look up the supplementary table 66 of the technical textbook for drying agricultural products: λ = 0.028 (W/m 0 K) γ = 19.06 × 10 -6 (m 2 /s)

It follows that the mode of the air in the drying room is the vortex mode

4.1.4 Average temperature difference between the drying agent and the surrounding environment

∆t1: Temperature difference between the drying agent entering the drying room and the outside air

∆t2: Temperature difference between the drying agent leaving the drying room and the outside air

Dimensions of each layer of mortar δv = 0.01 (m)

Hot fluid (hot air) moves in the room due to natural convection (because of temperature difference) and forced air movement (fan) Air moves in vortex mode (due to

We call α1 is the coefficient of heat transfer from the drying agent to the inner surface of the drying room wall α1 = k × (α1’ + α1’’) With α1’ is the coefficient of heat transfer from the drying agent to the wall of the dryer due to natural convection, W/m 2 0 α1’’ is the coefficient of heat transfer from the drying agent to the wall of the dryer due to natural convection W/m 2 0 k: adjustment factor, k = 1.2 ÷ 1.3 a) Calculate α1’

Nuxen's standard equation for a gas:

Nu = C × εl × R 0.8 = 0.018 × εl × R 0.8 With: εl depends on the ratio l ph/l td and Re

Look up the table and calculate we get εl = 1.205 [15]

We call tT1 is the average temperature of the pipe wall surface (wall) in contact with the air in the drying room

We call ttbk is the average temperature of the gas entering the drying room (drying agent) t tbk e + 45

Call ttb is the average temperature between the wall in the drying room and the average temperature of the drying agent t tb E + 55

Gratket norm: characterizes the effect of molecular friction and lift due to density differences at other high-temperature points of the symbol line Gr

With: g is the acceleration due to gravity g = 9.8 (m/s 2 )

Hph height of drying room, Hph = 2 (m)

On the other hands, the Nuxen standard is

Nu = H ph × α 1 ′′ λ suy ra α 1 ′′ =Nu × λ

Heat transfer coefficient of the outer surface of the dryer to the surrounding environment α2 = α2’ + α2’’

With: α2’: heat transfer coefficient due to natural convection α2’’: radiant heat transfer coefficient

We have the specific heat load of the air from the drying room to the surroundings: q1 = α1 × ∆t1 = 6.07 × (55-45) = 60.7 (kJ/kgmoisture) During steady heat transfer, q 1 =t T1 − t T2

3 i=1 = δ 1 λ 1+ δ 2 λ 2+ δ 3 λ 3 (m 2 0 /w) With: δ1, δ2, δ3: wall thickness (m) λ1, λ2, λ3: Corresponding coefficient of thermal conductivity (W/m 0 ) δ1 = δ2 = 0.01 (m); mortar layer thickness λ1 = λ2 = 1.2 (W/m 0 ) δ3 = 0.2 (m); the thickness of the brick has λ3 = 0.77 (W/m 0 )

We have tT2: Outside wall temperature of drying room ( 0 C) tT2 = tT1 – 17 = 45 – 17 = 28 ( 0 C)

The temperature of the boundary layer between the outer wall of the drying room and the outdoor air:

At temperature Tbg look up the table we can calculate: λ = 2.67 × 10 -2 (W/m 0 K) γ = 16.024 × 10 -6 (m 2 /s) The difference between the outside wall temperature and the air temperature is:

∆t2 = tT2 – t0 = 28 – 26 = 2 ( 0 C) Gratkey number standard is

C0: Radial coefficient of absolute black body: C0 = 5.67

Specific heat load from the surface of the outer wall to the atmosphere: q2 = α2 × ∆t2 = 7.79 × 2 = 15.58 kJ/kg moisture

So the loss through the wall:

4.1.5.2 The loss through the ceiling

Steel concrete layer with thickness: δ2 = 0.02 (m); λ2 = 1.55 (W/m 0 ) Insulation layer thickness: δ3 = 0.15 (m); λ3 = 0.058 (W/m 0 )

To calculate the loss through the ceiling we determine: α2tr = 1.3 × α2 = 1.3 × 7.79 = 10.13 W/m 2 K

Therefore, the coefficient of heat transfer through the ceiling Ktr is

So the loss through the ceiling:

Qtr = 3.6 × Ktr × Ftr × ∆t = 3.6 × 2.31 × (5.2 × 1.4029) × (55-26) = 1759.31 (kJ/h) Specific heat load q tr =Q tr

The two ends of the drying room have doors made of thick steel: δ4 = 5 (mm) has a coefficient of thermal conductivity λ4 = 0.5 (W/mK)

Therefore, the coefficient of heat conduction through the door Kc is:

The door on the side of the drying agent has a temperature difference (t1 – t0) and the other end has a temperature difference of (t2 – t0)

Substitute the number we have:

The average temperature of the drying agent is 85 0 C and assume that the wall of the drying room is 2m from the wall of the workshop [16]

Therefore, the ground loss is equal to:

Thus, the total heat loss transmitted through the enclosure structure to the surrounding environment is equal to:

Qmt = Qt + Qc + Qtr + Qn = 831.33 + 1599.98 + 1759.31 + 1313.11 = 5503.73 (kJ/h) q mt =Q mt

Additive euquipment calculation

Due to the quality requirements of the product after drying, the drying agent is hot air The hot air passes through the heating calorifer and receives heat directly from the saturated steam through the pipe wall The air used for drying has the required temperature of 100 0 C, the heat transfer medium is saturated steam

Equipment is a beam tube, saturated steam goes in the tube, air goes outside the tube Two cross-current motion fluids

4.2.1.2 Calculating the parameters of calorifer

Choose copper heat transfer pipe, ribbed to increase the heat transfer coefficient, the thermal conductivity of copper is λ = 385 W/m 0 [15]

Outer diameter of pipe: dng = 0.03 (m)

Diameter of tendon: Dg = 1.4×dng = 0.042(m)

High of tendon: h = (Dg – dng)/2 = 0.006 (m)

Number of tendons in a tube: m = l/bg = 100

Total length of tendons: Lg = b × m = 0.002 × 100=0.2(m)

Total length without tendon: Lkg = l – Lg = 1.0-0.2=0.8(m)

Amount of air required for reflux drying (according to actual calculation): l = 76.92 (kg/kg moisture)

L = 31884.11 (kgkkk/h) Specific volume of dry air

Amount of dry air entering calorifer:

V = L × Vtb = 31884.11 × 0.885 = 28217.44 (m 3 /h) Convection heat transfer coefficient α1:

Surface area of a tube : (inside of tube)

Ftr = π × dtr × l = 3.14×0.025×1.0 = 0.0785( m 2 ) Outer surface area of the tube:

Fng = dng×l = 3.14×0.03×1.0= 0.0342 (m 2 ) Area of the outer surface of a tube

Fg = π × Dg × Lg + π/4×Dg 2 – π/4×dng 2 = 0.02705 (m 2 ) Area part of without tendon

 Fbm = 0.02705+0.07536 = 0.10241 (m 2 ) + Choose the number of pipes lined up horizontally is: i = 20

+ The distance between these pipes is 0.05(m)

+ The distance between the outermost tube and the calorifer is: x= 0.01 (m) Free cross-section of a plane perpendicular to the direction of air movement:

Ftd= Fng - Ftr = 0.0942 - 0.0785 =0.0157 ,m 2 Choose the gas flow rate through the calorifer to be: 𝜔 𝑘𝑘 = 6m /s

2300< Re< 10 4 So the gas flow in the calorifer flows excessively

+ Nu number standard (calculated for the case where the fluid flows across the outside of the ribbed tube tendons):

With : dng : outside diameter of pipe; dng = 0.03 (m) bg : tendon ; bg = 0.01 (m) h :height of tendon ; hg = 0.006 (m)

C, n : quantities that depend on the arrangement of the tubes

Choose the arrangement of pipes to be aligned, so we have: C=0.116, n=0.72

+ Convection heat supply coefficient: α 2 =Nu ×λ b g !.6 ∗ 0.0315

+ Heat transfer coefficient from saturated steam to pipe wall 𝛼 1 α 1 = 2.04 × A × ( r

H = 1.0 : height of pipe r : latent heat of vaporization J/kg [15] r = 2208×10 -3 J/Kg

+ The coefficient A has a value that depends on ttb

Choose tT = 110 0 C: Heat pipe wall temperature t tb =t T + t hnd

So substitute the number in, we get:

+ Calculate the coefficient of heat transfer from the outside of the pipe to the air moving inside calorifer α2

+ Fluid flows through the outside of the pipe into a tendon pipe: α 2 = 68.04 (Due to selection of air flow rate ω kk = 6m/s )

Actual convection heating coefficient: α 2tt 2 W/m 2 degree k = 1

So the specific heat: q2 = k×tTB ".4×120 = 2688 ,KJ/Kgmoisture

So all the above hypotheses are acceptable

4.2.1.3 Determination of heat transfer surface

The amount of heat provided by the calorifer: q s = I 2 − I o x 2 − x o −Δ [16]

We have: Δ= −12.98J/Kg moisture q s 6.268 − 69.76 0.029 − 0.0172 + 12.98 = 6388.38(J/Kg moisture)

Qs = qs × W = 6388.38 × 313.5 = 2002.757 (KJ/h) Calorifer performance, choose η= 0.9

Actual amount of heat provided by calorifer:

Let D be the amount of steam consumed in 1 hour

Actual amount of heat transferred from the steam in the tube to the wall:

Number of heat transfer tubes in calorifer: n = F t

Number of tubes stacked horizontally: m = n i 78

Select the number of tubes arranged horizontally 19 tubes

Number of tubes lined up is 20 tubes

+ The length of the calorifer

Hx =l+2a =1+2×0.1=1.2( m) a: thickness of each shield

Due to the requirements of mango cleanliness as well as exhaust gas, people use hot air drying agent During the drying process, the air moves at high speed, so part of the mango will follow the air out To recover exhaust gas and mango, a xylon is placed in the outlet pipe of the hot air for a cleaner separation

At 65 o C, the specific volume of air is:

C = 0.97 (m 3 /Kg) Air flow out of the drying room (into the xylon)

We call 𝛥𝑃 is the resistance of the xylon, then:

𝜌 𝐾 = 540 So that, 𝛥𝑃 = 540 ∗ 1.029 = 555.66 Conventional speed is Wq

The diameter of the xylon is:

𝑞 ∗3600=0.65(m) Based on the diameter of D = 650mm, we choose single xylon LIH-15 Basic size of cyclon LIH-15

Center pipe height with flange : h1 = 1.74D=1.13(m)

Distance from end to flange : h5 = 0.32D=0.2(m)

Tilt angle of inlet cover : 𝛼 = 15 o

Diameter of the xylon : D = 650mm

The resistance coefficient of the xylon : 𝜉 = 105

4.2.3 Calculate resistance and select fan

The fan is the part that transports the air and creates pressure for the gas to pass through the equipment: Calorifer, dryer, pipe, xylon The energy generated by the fan provides the gas stream with a kinetic pressure to move and a part to overcome the resistance on the transport pipeline

Fan performance is characterized by the volume of air entering or leaving the dryer Use two fans:

One is used to absorb the exhaust gas at the xylon entering the calorifer One is both new air intake and exhaust gas return to the calorifer

4.2.3.2 Calculate the resistance of the whole process

➢ Resistance from fan to calorifer

Select the pipe connecting from the fan mouth to the calorifer with a diameter of 0.3 (m ), length l= 3m

The velocity of the gas in the tube is: ω d = L′

Re = 20×104>104 So the air flows in the tube according to the vortex flow mode The vortex movement is divided into 3 zones

+ Zone 1: Hydraulic smooth: This area roughness does not affect the coefficient of friction

𝜀 −4: Relative snow roughness of corrugated iron [16]

+ Zone 2: Rough area: This area the coefficient of friction depends on the roughness and does not depend on Re

So the coefficient of friction is calculated by the formula: λ = 0.1 ∗ (1.46 ∗ ε d+ 100

So the resistance on the tube from the fan mouth to the calorifer is: ΔP 1 = λ∗l∗ρ∗ω 2

The average temperature of the hot air in the calorifer is: ttb = 100+26

At this temperature look up the table we have: 𝜆 = 0.0292 (W/m o K)

𝛾 = 19.01 ∗ 10 −6 (m 2 /s) The velocity of the air in the calorifer is: ω = L ′

4(1.2∗1.8) 2(1.2+1.8) 19.1∗10 6 = 0.3 ∗ 10 6 Re>104 So the air moves in a vortex mode

Because the pipes are arranged in a corridor style, so ξ= (6 + 9m) ( s d) −0.23 (R e ) −0.26 [16]

Where s is the distance between pipes in the cross-sectional direction of the moving stream (in the width of the stream)

S=0.005+0.006+0.03/2 =0.026 (m) With: m is the number of beam sequences in the direction of motion m = 19 d: pipe diameter: d = Dg = 0.049(m) => 𝜉 421

So the calorifer resistance is: ΔP 2 =ξ∗ρ∗ ω 2

➢ Resistance due to opening punch in calorifer

Area of the cross-section of the ejector tube

2) 2 = 0.07065, 𝑚 2 Cross-sectional area of hot air duct:

So the resistance due to opening punch in calorifer is: ΔP 3 =ξ∗ρ∗ ω 2

➢ Surge resistance from calorife to hot air duct

𝜌 = 0.916 (Kg/m 3 ) Cross-sectional area of hot air duct

4 = 0.07065 ,m 2 Velocity of hot air in the tube ω kk = L ′

23.13∗10 −6 = 15 ∗ 10 4 Re>104: So the air moves in a vortex mode

So the resistance due to stroke at calorifer is:

➢ Pipeline resistance from caloifer to drying room

Calculating like a tube from the fan mouth to the calorifer we get:

So the gas is in the transition zone 𝜆 = 0.0162

So the resistance on the gas pipeline is: ΔP 5 =λ∗ l ∗ρ∗ω 2

➢ Impedance of punching opening into the drying room

Pipe cross-sectional area Fo = 0.07065 m 2

Horizontal area of drying room F1 = h×R =1.183×1.82 = 2.153(m 2 )

So the impedance of punching opening into the drying room: ΔP 6 =ξ∗ρ∗ ω 2

➢ Thrust resistance collected from drying room

The temperature out of the drying room is t2 = 65 o C 𝜌 = 0.996 (Kg/m 3 )

20.02∗10 −6 ×10 4 Re>104 air in vortex mode

➢ Resistance of gas pipeline from drying room to xylon

This pipeline is divided into 2 sections:

+ Section 1: come out from the drying room, choose a pipe with a diameter of 3(m),width l=1.5(m)

Air velocity in the tube: ω kk = V 2

20.02∗10 −6 = 18 ∗ 10 4 Re>10 4 so the air moves in a vortex mode ΔP 9 = λ∗l∗ξ∗ω 2

2∗0.3 = 5.7 (N/m 2 ) + Section 2: from the end of section 1 to the xylon, choose a pipe with a diameter 3(m),length l=8(m)

Select pipe with diameter d=3m,width l=1.5m ΔP 11 = λ∗l∗ξ∗ω 2

➢ Air pipe resistance from exhaust fan to xylon

Select pipe with diameter d=3m,length l=4m ΔP 12 = λ∗j∗ξ∗ω 2

4.2.3.3 Calculate steam capacity and select fan

➢ Fan pushes the air mixture into the xylon

Qđ = Vđ = L’ × vt’M = 27588(m 3 /h) Total pressure:

Hp : Computational impedance of the system

Hp = 𝛥𝑃 !28.11 (N/m 2 ) t’M : Working temperature of gas mixture t’M = 48.4 o C

B = 760.8 mmHg : pressure at the place where the fan is located

𝜌 : Density of gas at standard conditions 𝜌 = 1.181𝐾𝑔/𝑚 3

𝜌 𝑘 : density of gas at working condition 𝜌 𝑘 = 1.08,Kg/m 3

Power on electric motor shaft:

With η tr = 0.95 : Drive through the pulley η q : Fan performance, choose 72%

Power setting for electric motor:

Nđc = N×k3 ,(KW) With k3 is the reserve factor

+Power on electric motor: N = 1.45,KW

+Power setting for electric motor: Nđc = 1.45×1.25=1.8125, KW

Both fans use centrifugal fan type II4.65N o 4 với cùng một hiệu suất 𝜂 = 0.72

Calculation and equipment selection

4.3.1 Calculation and selection of equipment for the production line of dried mango slices

After being brought to the factory, the materials will be weighed according to the quantity to be produced, the workers will weigh the raw materials

− Number of workers in the process: 2 people, 1 person will put ingredients on the scale and 1 person will observe the scale and record the parameters

Working principle: Mango is the raw material that runs on the conveyor belt, workers stand on both sides of the conveyor belt, select the satisfactory fruits and classify them by shape, color, and size Two workers stand 0.5m apart

Productivity in the process: G2v = 848.71 kg/h

B: conveyor width B = 0.75m y: specific gravity of mango, y = 700 kg/m 3 v: conveyor speed, v = 0.12 m/s ŋ: utilization factor of conveyor, ŋ = 0.6 h: average height of mango layers, h = 0.125 m

Substituting the number in we get:

The number of conveyors selected is n = 848.71

➢ Calculate the number of workers

In fact, a worker at IFOOD factory can make 10 (fruits/minute) Average weight of each fruit: 350g, worker's productivity in 1 hour:

210 = 4.04 So we choose 4 workers to work

We use 1 conveyor, 4 workers are distributed on both sides of the conveyor, 2 workers on each side

 The size of the load to choose: L×W×M = 3000 × 750 × 1000 mm

Working principle: washing process consists of 2 stages: soaking phase and washing phase The equipment is composed of a stainless steel conveyor belt and large volume water tank The conveyor belt is divided into three parts, the horizontal part is submerged in water, the inclined part has strong water jets and a horizontal part is on the high side During the soaking stage, the material on the horizontal part is submerged in water, the dirt on the surface of the material is peeled off The moving conveyor will carry the material gradually towards the inclined part The efficiency of the soaking process is enhanced by blowing air to disturb the water and materials on the surface, increasing the contact area of the material and water, so the soaking time is shortened When the material moves to the incline of the state, water jets with high pressure up to 2 ÷ 3 at wash away the dirt At the end of the washing process, the material moves to the upper horizontal section to be drained [43]

Productivity in the process: G3v = 830.43 (kg/h)

Feed and discharge time is 5 mins

1000×60 = 0.139 ⟹ Select 1 device Number of workers: 1 person

4.3.1.4 Peeling, slicing, and seeding conveyors

After washing, mangoes will be transported on conveyor belts, workers will stand on both sides to peel and slice

B: Conveyor Width, B = 0.75m y: Specific weight of mango, y = 700 kg/m 3 v: Conveyor speed, v = 0.12 m/s ŋ: Conveyor belt utilization factor, ŋ = 0.6 h: Average height of mango layers, h = 0.1 m

Substituting the number in we get:

Number of conveyors to choose: n = 829.60

➢ Calculating the number of workers:

Productivity of slicing, removing seeds: G4v = 829.60 (kg/h)

Q: productivity per worker in 1 hour

A worker can make 6 mangos/minute Average weight of each mango: 350g

We use 1 conveyor, distributed 6 workers standing on both sides of the conveyor, 3 workers on each side

L2: length of drive unit and drum (m), L2 = 1.5 (m)

 Conveyor size to choose: L×W×H = 4125 × 750 × 1000 mm

Figure 3 5: Peeling and Slicing Conveyor

Working principle: the material is put into the trays and put into the blanching conveyor of the equipment Water is heated to the required temperature to blanch and disinfect materials In the blanching chamber, in different locations, install a thermal sensor to control the temperature uniformity of the whole blanching chamber The temperature can be adjusted automatically After blanching, the raw materials are taken to the cooling chamber to cool down, ensuring the color and flavor of the ingredients

Productivity of blanching stage: G5v = 555.83 (kg/h)

Select blanching device conveyor belt model of Hitrees (Hainan) Industries Co., Ltd

➢ Calculation and selection of equipment

Productivity in the process: G5v = 555.83 (kg/h)

Table 3 9: Parameters of blanching equipment

Working principle: After blanching, the mango will be put into the sugar water bath after cooking, put into the syrup container, then it will be pumped into the soaking tub to soak the mango

Table 3 10: Parameters of soaking tub

Productivity in the process: G6v = 560.27 (kg/h), Mdd = 1375.68 (kg/h)

The volume of the tank required is: V = V xoài + V dd = 550.27

With: density of mango is 700 (kg/m 3 ), the density of the soaking solution is 1.204 × 10 3 (kg/m 3 ) [45]

So the number of soaking tub needed: 𝑛 = 1.92

4.3.1.7 Equipment for rinsing and drying

Working principle: The working way is same as mango washing machine Mangoes, after soaking, are put into a washing machine to wash away dirt and impurities that stick to the surface of the fruit Water is filtered and recirculated to save costs

Table 3 11: Rinsing and drying equipment parameters

Productivity in the process: G7v = 544.77 (kg/h)

Number of devices to use: n = 545.625×5

Number of workers: 2 people After washing, workers put mangoes on trays and put them on shelves to drain

Figure 3 8: Rinsing and drying equipment

Working principle: After drying, the mangoes are put into the multi-stage conveyor drying device to dry and separate the moisture in the raw materials to achieve the requirements of the product Raw materials go from the top-down, removed at the end of the device, drying in the same direction combined with the opposite direction Moving in a zigzag pattern makes the material to be disturbed, the drying agent is in contact with the material more evenly

Table 3 12: Parameters of drying equipment

With W is the amount of moisture evaporated in 1 hour

Number of devices to choose: n = 414.66

600 = 0.55 So choose 1 device Number of workers: 1 person

Working principle: Stainless steel conveyor belt can work in high temperature environment Good food resistance and corrosion resistance No slipping when pulling the load, light weight saves energy, easy to assemble, move and clean Easy to replace, cut and lengthen the conveyor belt

Figure 3 10: Stainless steel mesh conveyor belt

B: conveyor width, B = 0.75m y: specific gravity of mango, y = 700 kg/m 3 v: conveyor speed, v = 0.12 m/s ŋ: utilization factor of conveyor, ŋ = 0.6 h: average height of mango layers h = 0.1 m

Substituting the number in we get:

Number of conveyors to choose: n = 126.78

13608 = 0.1 So we choose 1 conveyor Choose 1 mesh conveyor, width 0.75 m transported at speed 0.05 m/s

With: τ: cooling time (40 phút) ρ: specific gravity of mango (Kg/m 3 ) l: length of drive unit and drum (m)

 So the conveyor size : L×W×H = 3150 × 750 × 1000 mm

Calculate the number of workers:

Workers will stand on both sides of the conveyor to remove unsatisfactory pieces of mango

So the total number of workers on both sides of the conveyor is 4 workers

Working principle: After cooling and selecting the mangoes, they are taken to the packaging equipment to pack according to the specified volume, print the label name, expiry date as well as other necessary information to perfect the product and increase the quality of the product, preservation time, easy distribution and transportation to consumers

Productivity in the process G10v = 125.63 (kg/h)

750 = 0.167 So choose 1 device Number of workers: 1 worker

Figure 3 11: Sliced mango packing machine

Amount of water needed: Mntt = 708.76 (kg/h)

Amount of sugar needed: Md = 592.31 (kg/h)

Amount of ascorbic acid needed: Macid ascorbic = 68.78 (kg/h)

Amount of potassium thiosulfate needed: MK2S2O3 = 41.27 (kg/h)

Total amount to cook: 1411.12 (kg/h)

1.204 = 1172.03 (litre/h) With 1,204 (kg/l) is the density of 45% sugar solution [11]

Choose a double-shell crucible with a stirring blade and a tight lid as shown in Pic 3.12 and with the specifications shown in Table 3.13

Number of devices needed: n = M siro

900 ≈ 1.3 ⟹ Select 2 devices Number of workers: 1 person

Table 3 14: Specifications of the syrup cooking pot

Saturated vapor pressure 3 kg/cm 2

To cool the sugar solution, we use a plate heat exchanger with 4 0 C, water as an agent Solution temperature after leaving the device: 10 0 C

Number of devices to use: n = V dd

The volume of 45% soaking solution required in the dried mango production line:

Set the tank's filling factor to be 0.75 Select 1 container

Choose the retention time of the bin to be 1h

Volume of container to be stored: V t = 1.143×1

Let D be the bottom diameter and H the height of the container Choose H = 1.2D

The volume of the container is V = πD 2 H

4 = 2 (m 3 ) Let D= 1.29 H = 1.54 Container size is: D×H = 1290 × 1540 mm

Bunke is cylindrical in shape, with a conical bottom with an angle of inclination

88 α = 60°C, made of steel, choose the filling factor φ= 0,9

VT: volume of cylindrical part, (m 3 )

VN: volume of truncated cone, (m 3 ) m: amount of material to be processed, (kg)

According to the Fig 3.14 we have: V = πD 2

The amount of sugar the factory needs to use for the line of dried mango slices in 1 hour: Msugar = 592.31 (kg/h)

We have: the density of the sugar is: ρ = 1.5878 × 10 3 (kg/m 3 ) [52]

The volume of the bunke containing the sugar is: V = m ρ×∅= 570.43

According to the formula we have: D = √0.4+1.81×10 −3

2 × √3 = 0.46(m) h1 = D = 0.73 (m) Height of the entire bunke: H = h1 + h2 +h3 = 0.73 + 0.46 + 0.2 = 1.4 (m)

Select 1 bunke to hold the amount of sugar size: height × diameter = 0.73 × 1.4 (m)

Select the MAXANA industrial food pump with the specifications shown in Table 3.15

Select all 8 pumps In which, 2 pumps located at 2 sugar cooking pots are used to pump the sugar solution after cooking to 2 filter devices, 2 pumps at the filter device to pump the filtered sugar solution to the chiller, 1 pump at the sugar cooler Refrigerating the sugar solution is used to pump the sugar solution after cooling to the container, 1 pump is located in the sugar solution container, 1 pump is located in the soaking tub to pump the solution after soaking The other pump is used for the line to put the chemical soaked solution into the soaking tub

Table 3 16: Summary of equipment for the line of dried mango slices

7 Equipment for rinsing and drying

CALCULATION AND ORGANIZATION

Factory organization chart

Working mode

Administrative block works 8 hours/day

The production workshop works in shifts, each shift is 8 hours The factory is closed on Sundays, public holidays and Tet holidays of the year Administrative department works

Main factory and auxiliary parts work 3 shifts/day:

Manpower working in the factory

Order Position Number of workers

5.3.2 Human resources working directly in the main production workshop

Table 5 2: Manpower for the production line of dried mango slices

1 Weight materials 2 person/machine/shift 3 6

2 Select and categorize 4 person/machine/shift 3 12

6 Soaking sugar solution 1 person/machine/shift 3 3

7 Rinsing and drying 2 person/machine/shift 3 6

8 Conveyor drying 1 person/machine/shift 3 3

11 Cooking syrup 1 person/machine/shift 3 3

20 Driver 2 person/vehicle/shift 3 21 (4 trucks)

22 Cleaning and laundry staff 2 person/shift 3 6

➢ Extra manpower in the workshop

Table 5 3: Extra manpower in the workshop

Order Position Number of workers/shift

3 Shipping products through the warehouse 2 6

The largest workforce in a production shift is: 29 + 72 + 13 = 114 (person)

So the total workforce of the factory is: 29 + 165 + 39 = 233 (person)

Constructiveness

5.4.1 Features of the factory construction site

The terrain is flat, the slope is not more than 1%, it is built near the national highway, so it meets the requirements of the factory and has the ability to expand production

Build on stable land Through exploration by geologists, the land below has no minerals, so it should be used to open an industrial park

Wind direction: the main wind direction of this land is southwest

Around the factory, there is a green campus to create a fresh environment suitable for workers and create more aesthetic beauty of the factory

In the production technology of dried mango slices, raw materials are mainly transported by buckets and conveyors On the other hand, the equipment used in the production line is not high Based on that technological feature, we choose the production workshop as a 1-storey house Such a construction will be convenient for the arrangement of equipment, displacement and the organization of natural lighting for the workshop

5.4.2.1 Traffic problems in the factory

The plant is protected by high walls The factory floor is clear, the road is flat, high, easy to drain

In addition to the main gate, the factory also has an additional gate to ensure the most convenient transportation of raw materials, products and travel

Based on technology requirements, the number of equipment to choose, we have the size of the main production workshop in the shape of a rectangle

Has a rectangular shape with dimensions:

− Length of main production workshop: 66m

− Width of main production workshop: 18m

− Height: 7.2m roof is not included

− The house has a reinforced concrete structure

* Cement layer 100mm * Bearing layer

* Corrugated iron layer * Steel frame

House column: bearing column 600 × 400; gable windproof column 400 × 400 (mm)

The foundation is resistant to moisture and loads, the structure consists of:

* Cement layer: 100 (mm) * Bearing concrete layer: 200 (mm)

* Buffer sand layer: 200 (mm) * The bottom layer of compacted earth

The house is arranged with reasonable main doors and windows, using steel horizontal push doors

Location of main production workshop: located in the middle of the factory's planned land area, related workshops and warehouses are located nearby such as: raw material warehouse, finished product warehouse, electromechanical workshop, boiler room, operating area main In the workshop, there are fire extinguishers placed in the corners to facilitate fire prevention and fighting

In the main production workshop, we build 2 QC and foreman departments with sizes respectively: 6 × 3 × 4 (m) and 6 × 3 × 4 (m)

Choose 1 room located at the main gate and the other room at the side gate of the factory

− Restroom (1 room for men and other for women): 4 × 4 × 4 (m)

Construction of 2-storey house with size: 30 × 6 × 8 (m)

Total area of administrative area: 30 × 6 = 180 (m 2 )

Calculate for 2/3 of the largest number of employees in 1 shift: 114 × 2

With 114 people is the largest number of employees in a production shift

Standard area is 2.25m 2 for 1 worker

Calculate more for the corridor and the whole cooking area we choose:

Choose the area of the dining room: 14 × 8 × 4 (m) Area is: 14 × 8 = 112 (m 2 )

Toilets are arranged in the main production workshop for convenience and hygiene before entering production and are divided into many rooms for men and women: men's restroom, men's bathroom, men's clothes changing room, women's restroom, women's bathroom, women's changing room, laundry room, clothing distribution room and labor protection

Activity house for 60% of the workforce of the largest shift: 0.6 × 114 = 69 (người)

In the food factory, female workers make up the majority and usually account for 70%, men account for 30%:

Number of male workers: 69 × 30% = 20.7 person, we choose 21 person

Number of female workers: 69 – 21 = 48 (person)

Changing room: choose 0.2 (m 2 /person) Acreage: 0.2 × 13 = 2.6 (m 2 )

Bathroom: choose 6 people/room Choose 3 rooms, with each room size 0.9×0.9(m)

Restrooms: the number of bathrooms is equal to ẳ of the number of bathrooms, choose 1 room, the size of each room 0.9 × 1.2 (m)

 So the total area of the rooms reserved for men is 2.6 + 2.43 + 1.08 = 6.11(m 2 )

Changing room: choose 0.2 m 2 /người Acreage: 0.2 × 28 = 5.6 (m 2 )

Bathroom: choose 7 people/room Choose 5 rooms, with each room size is 0.9 × 0.9(m)

Restrooms: the number of bathrooms is equal to ẳ of the number of bathrooms, choose 2 room, the size of each room 0.9 × 1.2 (m)

 So the total area of the rooms reserved for women: 5.6 + 4.05 + 2.16 = 11.81 (m 2 )

Charged for 15 people/ 1 sink Each sink takes up space 1m 2

The area of sinks is: 4×1 = 4 (m 2 )

 So the total area of the toilet area is: 6.11 + 11.81 + 3 = 20.92 (m 2 )

Choose toilet size: 7×3×4 (m) Area is: 7×3 = 21 (m 2 )

The toilet is located in the main production workshop

The amount of mango ingredients needed for 1 hour is M = 857.28 kg/h

Amount of ingredients needed for 4 days: 857.28 × 24 × 4 = 82298.88 (m 3 )

Ingredients are graded according to standards: d = 700 (kg/m 3 ) Maximum material layer height: h = 3m compared to the height of the house is 6m

Volume of ingredients to contain:

3 = 39.19(m 2 ) Walkways and columns account for 30%: 0.3 × 39.19 = 11.76 (m 2 )

 Then choose the warehouse size as: 9×6×6 (m), area : 54 (m 2 )

The incubation area is integrated with the storage of raw materials Mangoes with unsuitable ripeness will be sent to incubation area Suitable fruits will be produced

0.5 = 6030 (𝑝𝑎𝑐𝑘𝑠/𝑑𝑎𝑦) With 0.5 (kg) is the weight of 1 pack of dried mango

For 1 box of products with weight 10 (kg) = 20 (packs/boxes)

 So the number of boxes of mangoes produced in 1 day is: 6030

The shelf life of finished products in stock is 15 days So, the number of boxes in the warehouse is: 302 × 15 = 4530 (boxes)

Choose the size of the box enough to hold 20 packs is: 800 × 480 × 300 (mm)

The volume of 1 box is: 0.1152 (m 3 )

The required storage volume to hold all boxes is: 4530 × 0.1152 = 521.86 (m 3 ) Mango boxes are arranged 10 boxes/stack, 1 stack height h = 2 (m)

2 = 260.93(𝑚 2 ) Walkways and columns account for 30%: 260.93 × 30% = 78.28 (m 2 )

 Storage area for dried mango slices: 260.93 + 78.28 = 339.21 (m 2 )

 Then choose the warehouse size as: 23×15×6 (m), area: 345 (m 2 )

5.4.2.9 Warehouse for auxiliary materials and packaging

Build a warehouse with a minimum size of enough RE sugar to supply for 7 days production

The amount of RE sugar required for the production of sliced dried mango is: MRE 592.31 (kg)

 So the amount of RE sugar needed in 1 day is: MRE = 592.31 × 24 = 14215.44 (kg)

RE sugar is stored in bags weighing 50 kg

In the warehouse, the bags are placed horizontally, the bags are stacked in stacks, each stack is 15 bags

The height of each stack is: 0.3 × 15 = 4.5 (m)

The area of each horizontal bag is: 0.8 × 0.4 = 0.32 (m 2 )

Ssugar = (x × n × N × f)/(nđ × nk) With: n: number of days of storage, n = 7 days nđ: weight of 1 bag of sugar, nc = 50 nk: how many bags of sugar in 1 stack, nk = 15

N: amount of sugar to melt in 1 day, N = 14215.44 (kg) f: occupied area per bag F = 0.32 m 2 x: factor taken into account the distance between bags, choose x = 1.1m

The area of the road RE occupied is:

Walking area in warehouse (F2) occupy 30% compared to the area occupied by the

 Total area of sugar storage area:

Warehouse design for 7 days of production

Amount of ascorbic acid used: Macid ascorbic = 68.78 (kg/h)

Amount of ascorbic acid used in 1 day: Macid ascorbic = 68.78 × 24 = 1650.72 (kg/day) Ascorbic acid is contained in bags weighing 25 kg

Area occupied by each bag: 0.4 × 0.2 × 0.15 (m)

In the warehouse, there are horizontal bags stacked on top of each other, 15 bags each stack

Sacid = (x×n×N×f)/(nđ × nk) With: n: number of days of storage, n = 7 days nđ: weight of a bag, nc = 25 nk: number of bags in 1 stack, nk = 15

N: Amount needed in 1 day, N = 1650.72 (kg/day) f: occupied area per bag, f = 0.08 m 2 x: factor taking into account the distance between bags, choose x = 1.1m

The walking area in the warehouse accounts for 30% of the occupied space:

 So the storage area for ascorbic acid: F’ = 2.72 + 2.72 × 0.3 = 3.54 (m 2 )

Warehouse design for 7 days of production

Amount of potassium thiosulfate used: MK2S2O3 = 41.27 × 24 = 990.48 (kg/day) Potassium thiosulfate is contained in bags weighing 25 kg

Area occupied by each bag: 0.4 × 0.2 = 0.08 (m 2 )

In the warehouse, there are horizontal bags stacked on top of each other, 15 bags each stack

SPotassium thiosulfate = (x × n × N × f)/(nđ × nk) With: n: number of days of storage, n = 7 day nđ: weight of 1 bag, nc = 25 nk: number of bags in 1 stack, nk = 15

N: Amount needed in 1 day, N = 990.48 (kg/day) f: occupied area per bag, f = 0.08 m 2 x: factor taking into account the distance between bags, choose x = 1.1m

The walking area in the warehouse accounts for 30% of the occupied space:

 Storage area for potassium thiosulfate: F’ = 1.63 + 1.63 × 0.3 = 2.12 (m 2 )

Packaging for dried mango slices production line is mainly PE bag, used to store dried products, so it needs to be carefully preserved Warehouse to store packaging for 1 month Choose the size of the packaging warehouse: 5 × 3 × 6 (m), diện tích: 15 (m 2 )

So the total storage area for auxiliary materials is:

A transformer station to lower the high voltage from the high voltage grid to the low voltage grid for the factory to use The station is located in a low-traffic position, arranged in a corner of the factory to ensure the safest

The electromechanical workshop is responsible for repairing machinery and equipment in the factory, and at the same time, it is also engaged in manufacturing, technical improvement and promotion of new initiatives

The area of the house depends mainly on the size of the generator

Choose size: 6 × 6 × 6 (m) Area of power station: 6 × 6 = 36 (m 2 )

The area of the house depends mainly on the size of the boiler

Is a place to store chemicals for cleaning, FO, DO oils, lubricants used to lubricate machine parts in the factory

5.4.2.15 Wet and dry scrap warehouse

This is the place where the factory's scraps are stored, divided into two parts: the dry and wet waste storage areas

Choose stock size: 6×6×6 (m) Warehouse area is: 6×6 = 36 (m 2 )

5.4.2.16 Water supply and water treatment area for production

Built in the ground and protruding 0.5m, above the ground

The purpose is to get water from the ground to be treated, tested and put into use

Water softener to provide water that meets technological requirements for production The water storage tank for treatment has the same volume as the water storage tank

 Choose the size of the water supply area: 12×6×6 (m) Area: 12×6 = 72 (m 2 )

Industrial wastewater flow fluctuates depending on the model, nature of products, technological processes of each factory, but in general, it is characterized by a wastewater treatment tank system consisting of many tanks such as a collection tank , conditioning tank, biological tank, and settling tank

This is the wastewater treatment area from the cleaning of equipment and floors in the factory There is also wastewater from raw material processing Waste water after being treated to meet Grade A standards is discharged into the environment to ensure no pollution to the surrounding area

Choose the size of the wastewater treatment area: 12 × 6 × 6 (m) Area: 12 × 6 = 72 (m 2 )

The water here is domestic water to provide for production and daily life Select tower with parameters:

The diameter of the tower is 4m Water tower height 4m

In order to facilitate future production expansion, there is an expansion area in the factory

The expanded land area is equal to 75% of the area of the main production workshop:

The area of the workshop area is 1188 (m 2 )

Choose the size of the expansion area is 64×14 (m)

Consisting of two consecutive areas, one for bicycles and motorbikes, the other for four-wheeled vehicles of officials

Calculated for the largest 60% of the factory's employees: 85 × 0,6 = 51 (person) Choose 1 motorbike/1m 2 and 3 bicycles/1m 2 Garage area calculated for the entire number of employees riding motorbikes and bicycles: 51/1 = 51 m 2

 The size of the garage for bicycles and motorbikes: 10 × 6 × 4 (m)

The number of cars of the staff is about 5, each occupying an area of about m in width 5m 2 So the area occupied by the car is: 5 × 5 = 25 m 2

So the general size for the garage is: 10 × 8 × 4 (m) Area is 80 (m 2 )

The factory has about 10 cars for transportation, but the number of cars in the factory is about 3 at a time, each car has an average width of 2.5m; additional walkway about 0.5 m

So the width for 5 pieces is: (2.5 + 0.5) × 3 = 9 m

Choose a garage with dimensions: 9 × 4 × 4 (m) Garage area: 9 × 4 = 36 (m 2 )

Choose a scale house with size: 4 × 5 (m)

The area of the house is as follows: 4 × 5 = 20 (m 2 )

5.4.2.23 Room for date printing, labeling, packaging

Placed next to the finished product warehouse so that the product can be labeled and transported to the finished product warehouse as quickly as possible, date printed, boxed and put into the finished product warehouse for preservation before shipment

Table 5 4: Summary of construction works of the whole factory

Order Name of construction Dimensions

7 Warehouse for auxiliary materials and packaging 14×6×6 84

13 Wet and dry scrap warehouse 6×6×6 36

14 Water supply and water treatment area 12×6×6 72

20 Room for date printing, labeling, packaging

Calculating plan for factory constructions

Calculate according to the formula:

Fkd: is the factory land area

Fxd: is the total area of the building

Kxd: is the construction coefficient

Choose a construction site with the size 136 × 75 (m), area is 10200 (m 2 )

5.5.2 Calculate the utilization factor K sd

Calculate according to the formula:

Ksd: is the coefficient used to evaluate the economic and technical criteria of the total factory site

Fsd: the usable area of the calculator plant according to the formula:

Fsd = Fcx + Fgt + Fhl + Fxd + Fhr

− Fcx is the area planted with green trees: Fcx = 0.4 × Fxd = 0.4 × 3542.24 1416.896(m 2 )

− Fhl is the area of the corridor: Fhl = 0.25 × Fxd = 0.25 × 3542.24 = 885.56 (m 2 )

− Fgt is the area of land for traffic: Fgt = 0.45 × Fxd = 0.45 × 3542.24 = 1594.008 (m 2 )

− Fhr is the sidewalk area: Fhr = 0.1 × Fxd = 0.1 × 3542.24 = 354.224 (m 2 )

− Fxd is the total area of the building: Fxd = 3542.24 (m 2 )

ECONOMIC CALCULATION OF FACTORY CONSTRUCTION

Calculation of electricity - water – cold

Electricity used in the factory is mainly: electricity for lighting and power

Light should be evenly distributed, without shadows and without blinding

Must ensure minimum brightness Emin

We use the specific illuminance method By this method we know 1m 2 of house needs a specific lighting capacity of p (W/m 2 ) Thus, on the entire area of the house, the capacity is:

P = p × S (W) Number of bulbs to be counted: n = P

With pđ: wattage of light bulb (W)

We use fluorescent lights 40W-220V, length 1.2m

Brightness requirements vary depending on the function of the place to be illuminated:

Table 6 1: Required brightness of areas in the factory

Finished products warehouse, auxiliary material warehouse, raw material warehouse, toilet bathroom

The main production workshop can be said to be the area with the largest area in the whole factory, where many people gather and directly process products Therefore, this area must ensure the following basic requirements:

− Must ensure absolute food safety and hygiene Processing areas must be completely isolated from other areas Before entering the processing area, it must be disinfected by going through the washing tanks mixed with sterilizing chemicals

− People entering the processing area must change clothes and wear protective clothing, thick protective boots as required, not wear normal clothes to enter this area

− The processing area must be regulated with the required temperature Temperature and humidity must meet the requirements, depending on the type of food

− The wall of the processing area is covered with 100% glazed tiles and the glass is installed above so that outsiders can monitor and observe all activities inside the processing area through the glass

− Processed water must meet technical requirements

− Water supply and drainage in the processing area must be the best because this area uses a huge amount of water during the day In particular, the drainage ditch of the processing area must be large, well drained and hygienic to avoid creating a source of infection from there

− The area of the processing area must be large and open to ensure the necessary needs for workers to work most conveniently

− The entry and exit of the processing area can be done through the main doors, but it is best to go through the specialized doors, it has the same structure as the windows on the sliding table layout to bring the products in and out favorable

− Lighting requirements: Lighting for processing areas must meet international standards, reaching about 12 W/m 2 b) Calculation:

Lighting capacity in the main production workshop is:

The lighting power in the permanent protected room is:

Total area of administrative area: 30 × 6 = 180 (m 2 )

The lighting capacity in the administrative area is:

The lighting capacity in the canteen is:

The size of the material stock is: 9×6×6 (m), area is: 54 (m 2 )

Lighting capacity in the raw material warehouse is:

The finished product warehouse size is: 23×15×6 (m), area is: 345 (m 2 ) The lighting capacity in the finished product warehouse is:

❖ Storage of auxiliary materials and packaging

Dimensions of the storage of auxiliary materials: 14 × 6 × 6, area is: 84 (m 2 ) The lighting capacity in the auxiliary material warehouse is:

Lighting capacity in the house where the generator is located is:

The lighting power in the boiler house is:

The lighting capacity in the warehouse is:

❖ Wet and dry scrap warehouse

Warehouse size: 6×6×6 (m) Warehouse area is: 6×6 = 36 (m 2 ) The lighting capacity in the warehouse is:

General dimensions for garages are: 10 × 8 × 4 (m) Area is 80 (m 2 ) The lighting power in the garage is:

The lighting power in the garage is:

The weighing house has dimensions: 4 × 5 (m) Area is: 20 (m 2 )

The lighting power in the weighing house is:

Dimensions of wastewater treatment area: 12 × 6 × 6 (m) Area is: 12 × 6 = 72 (m 2 ) The lighting power in wastewater treatment area is:

Lighting capacity in the workshop is:

❖ Room for date printing, labeling and packing

The lighting capacity in the room is:

Lighting capacity in toilets is:

❖ Lights to illuminate the way in the factory

Arrange 1 bulb every 10m, about 40 bulbs, each with a capacity pđ@ W The path illuminance is: P = n × pđ = 40 × 40 00 (W)

Table 6 2: Summary table of lighting capacity in departments

7 Warehouse for auxiliary materials and packaging 84 840

12 Wet and dry scrap warehouse 36 432

17 Room for date printing, labeling, packing 70 840

Table 6 3: Capacity of equipment used in the factory

4 Peeling, slicing, and seeding conveyors 0.05 1 0.05

6 Equipment for rinsing and drying 1.8 1 1.8

In addition to the above equipment in the factory, there are other types of dynamic loads such as exhaust fans, propeller fans, conveyors, water treatment stations, mechanical workshops We take 15% of the total dynamic loads mentioned above So the total electrodynamics of the whole plant is:

Pđl = 1.15 × 88.41 = 101.6715 (kW) The total capacity of the plant is:

Acs: Electricity consumption for lighting all year (kWh)

With: T = k1 × k2 × k3 k1: lighting time in a day (h) = 16 h k2: number of normal working days in a month = 26 days

120 k3: number of working months in the year = 12 months

Kc: Coefficient to use (Kc= 0.6)

Because the factory operates 3 shifts a day, so T = 16 × 26 × 12 = 4992 (h)

Ktt1: coefficient to use (Ktt= 0.6)

➢ Calculated load for lighting is calculated:

Ktt2: asynchronization factor of the lights (Ktt2= 0.9)

With: cosφ : Power factor, select cosφ = 0.9

6.1.2 Calculate the amount of water

6.1.2.1 Water for washing raw materials, processing

The amount of preliminary washing water accounts for 1.2 : 1 amount of mango The amount of soaking water accounts for 3 : 1 amount of mango

Amount of water needed for 1 day:

6.1.2.3 Water used to cook syrup

Amount of water required to make syrup ≈ 45 (kg/h)

Amount of water needed for 1 day:

6.1.2.4 Water used to wash ingredients

Amount of water needed for 1 day:

6.1.2.5 Water to wash equipment, floors

Amount of water needed to wash equipment, floors in 1 day:

Houses with a volume greater than 25000 m 3 We need to use 2 fire pump

One rated fire pump: 2.5 liters/second

Amount of fire fighting water within 3 hours

 Total amount of water needed in a day

 Total amount of water used in 1 year

Fixed capital

Economic calculation is an important and indispensable part of any factory Based on this calculation, we know the unit price, planning cost of construction, equipment installation, technology and related costs in the implementation process Thereby submitting to the competent authority for approval This is an indispensable part in the design of the building, it determines many areas and the success or failure of the factory

Based on the design capacity of the factory built and other important parts such as choosing a construction site, choosing a technology line, choosing equipment for the factory All the above calculations and selections require the plant designer to have a

124 general knowledge and in-depth understanding in order to find the optimal solution to bring the highest economic efficiency

6.2.1 Investment scale of the project

Construction investment project ‘Design a factory for drying sliced mangos’ at Tan Huong industrial zone, Chau Thanh district, Tien Giang province Total leasable area in the industrial park: 141 ha = 141×10 4 m 2 Investment projects in the form of new construction As calculated, we choose to rent the construction land with size 115 × 65 (m), area 7475 (m 2 )

6.2.2 Cost and land use demand of the project

Investment cost for construction is calculated by unit of m 2 multiplied by unit price based on actual experience for each work item

In addition to the above items, the factory needs to build roads, sewers, flower gardens, trees, Take 10% of the total construction cost Construction unit price for 1m 2 is 4×10 6 VNĐ

 Vxd = 3542.24 × 4×10 6 × 1.1 = 15,585,856,000 VNĐ (total are (table 5.4))

Factory depreciation expense is calculated at 5% of construction capital:

6.2.3 Cost of equipment and machinery

Table 6 4: Unit price of equipment and machinery

4 Peeling, seeding, and slicing conveyor belts

7 Equipment for rinsing and drying

Additional equipment (workwear, trays, crates, tables ) is taken at 15% of equipment capital, transportation and installation costs are taken at 10% of equipment capital

So the total value of the device is:

4,608,500,000 × (1 + 0.15 + 0.1) = 5,760,625,000 VNĐ Depreciation cost of equipment is equal to 10% of equipment capital:

Working capital

6.3.1.1 Calculating human resources for departments

Total number of workers and officials in the factory: 233 people

Total number of days in the year: 365 days

Number of days off: 52 Sundays

Number of public holidays: 4 New Year's Days and 4 major holidays of the year Number of days off for maintenance of machinery: 5 days

Number of working days: 300 days

Average salary per capita: 4,500,000 VND/month

Company monthly salary fund: 4,500,000 × 233 = 1,048,500,000 VND

The company's annual salary fund is

Insurance is calculated at 20% of salary fund

6.3.3 Cost of electricity - water for equipment

Annual electricity consumption is 421640 kWh

Average electricity price is 3000 VND/kWh

The total cost of electricity is:

 Cđ = 421640 × 3000 = 1,264,920,000 VND Annual water consumption 304 × 300 = 91,200 m 3

Average price of water 4000 đồng/m 3

So the total cost of electricity and water:

1 day production: Q = 258 × 24 = 6192 bags, the price of 1 bag is 1300 VND/ bag

Table 6 5: Cost of raw materials to produce finished products Ingredient Volume/year Unit price Cash (VND)

Clđ = Cl + Cbh + Cđn + Cbag + Cnl = 12,582,000,000 + 2,516,400,000 + 1,629,720,000 + 2,414,880,000 + 59,106,222,790 = 78,246,222,790 (VND)

Unit selling price – revenue – profit

6.4.1 Calculate the selling price of the product

Price for 1 box of products: p = C lđ

So we choose the market price is p= 45,000 (VND/box)

6.4.2 Factory revenue for the year

➢ Profit in the year before tax of the factory

In addition, businesses have to pay tax to the state, accounting for 28% of the total profit:

➢ Profit after tax of the factory (net profit)

Total fixed capital: Vcđ = 21,183,981,000 (VND)

So the payback time t = V cđ

PRODUCT QUALITY AND PRODUCTION SAFETY

Check and evaluate the quality of raw materials put into production

Purpose: to determine the cost of raw materials, maturity, dry matter content, pH index to take appropriate technological treatment measures

Checking raw materials when entering: checking the ripeness of mangoes, the degree of damage of the whole block of materials

Check raw materials during storage: temperature, humidity during storage for raw materials

Checking raw materials before processing: must ensure technical maturity Raw materials do not spoil, do not have a sour smell, do not rot

For all grades, in addition to specific regulations and tolerances, mangoes must:

− There are no rotten or reduced quality fruits that are not suitable for consumption

− Clean, almost no impurities visible to the naked eye

− Virtually not damaged by pests

− Not hurt by low temperature

− No abnormal moisture outside the case except in case of condensate when moving out of cold storage

− Fully grown and of suitable maturity

− If the fruit has a stem, the length of the stem should not exceed 1.0cm

The development and state of the right mango:

− Ensure that post-harvest ripening continues normally to the appropriate maturity

132 according to the characteristics of the variety

− Withstands shipping and handling conditions

− At the place of consumption, the quality is still maintained

− Ripeness, fruit color may vary depending on the variety

Mangoes are classified into 3 types as follows:

The mango fruit must be of the best quality and specific to the variety There shall be no defects, except very slight defects, provided that they do not affect the general appearance of the product, the quality, the retention of quality and the appearance in the packaging

The fruit mangoes are of good quality and are variety-specific The following slight defects are permitted provided that they do not affect the general appearance of the product, the quality, the maintenance of quality and the appearance in the packaging:

− Minor skin defects such as scratches or tans, dry lumps from sap (including long ones) and healed bruises with a total area of not more than 3; 4; 5cm2 for size groups A, B, C respectively

Consists of berries that do not meet the grade I or Premium quality but meet the minimum requirements specified in the “minimum requirements” The following defects are allowed provided that the mango fruit retains its essential characteristics with regard to quality, to the maintenance of quality and appearance::

− Minor skin defects such as scratches or sunburns, dry lumps from sap (including long ones) and healed bruises with a total area of not more than 5; 6; 7cm2 for size groups A, B, C respectively

− For grades I and II, the total number of brown spots dispersed on the skin, as well as yellowing of the green mango variety due to direct sunlight exposure, should not exceed 40% of the fruit surface area and there must be no sign of necrosis

Size is determined by fruit weight according to the following table

Table 7 1: Regulations on the volume of fresh mango

The maximum allowable difference between fruits in the same package belonging to one of the above size groups is 75, 100 and 125g respectively

Minimum weight of each fruit is 200g

The content of heavy metals in the product must comply with the maximum allowable limit (TCVN 4832:1989)

Pesticide residues in products must comply with the maximum allowable limit

Products subject to the requirements of this standard shall be prepared and handled as appropriate, such as the Code of Hygiene Practice and the Code of Practice

The microbial content in the product complies with the maximum allowable limit

7.1.2 Check the diameter and sugar water after cooking

The diameter must meet the requirements for color, not ferment, mold, not water According to TCVN 1695 - 88

After cooking, sugar water must be filtered, meeting the required clarity

Table 7 2: Residues of pesticides in mango fruit

Order Name of plant protection drug Maximum content

The correct food acid must be tested for the correct purity and concentration

Citric acid for food use according to TCVN 5516 - 1991.

Checking the stages in the production process

7.2.1 Checking the stages for the line of dried mango slices

Check the ripeness of raw materials: mangoes must be ripe to the correct technical ripeness (ripe but still have a certain firmness, not soft)

Check for damage: mangoes are not crushed

Inspection process: every 2 hours, a few fruits are taken to make a test sample, if the above criteria are not checked, the worker's working process must be adjusted

Check washing water quality, Ca(OCl)2 content in water and washing time

Check the cleanliness of the mango after washing

Testing process: take the wash water sample container to determine the content

Ca(OCl)2, if not correct, must be adjusted At the same time, randomly take a few sample mangoes to test, if the mango still has impurities and Cl2, it must be adjusted Test frequency: every 2 hours

7.2.1.3 Peel, slice, and remove seeds

It is required to remove all damaged fruits, impurities, fruit stalks if any

Check the size of the mango pieces after cutting

Test time: once every 2 hours check

Check the color of the product after blanching Request that the product after blanching is not tarnished

Check temperature conditions and blanching time

Test time: once every 2 hours check

Check the quality of the incoming sugar water Change the water periodically after 1 shift

Check the ratio of soaking sugar and mango juice

Check soaking time, sugar solution concentration The color and state of the product after soaking

Check the cleanliness of the washing water and change the water periodically

Check the parameters of the drying process: temperature, time

Check the density of mangoes on the conveyor, the speed of the conveyor

Check the temperature and cleanliness of the incoming air

Regularly check product moisture and product quality

Check and remove unsatisfactory mango slices in terms of color, size, crumbs, burnt, etc

Check the net weight of the product

Check the senses, packaging and information on the product

If not, it must be adjusted

Minimum requirements: Dried mango slices must have the following characteristics:

− Intact but still acceptable if there are some scratches

− The product does not rot or deteriorate during the manufacturing process

− No bruises, or dark spots

− Not damaged by insects or vermin

− No mold filaments visible to the naked eye

− There is no odor and taste is or if present is the salty taste of Sodium Chloride or Calcium Chloride or the mild sour taste of citric acid and the slight odor of preservatives and additives including Sulfur dioxide

− Packaging: Mango slices must be packaged in such a way as to protect the product properly The materials used inside the packaging must be clean and of good quality to avoid causing external or internal damage to the product The use of materials, especially paper and stamps bearing commercial specifications, must be permitted, printed and clearly labeled Packages must not have foreign objects inside

− The condition of the sliced dried mango should be such that it can be preserved during transportation to another location while maintaining the quality of the product

Check the outer shape and tightness of the packaging: the shape of the package is intact, not dented, the state of the packaging is not defective, and the label layer is not

The sensory parameters are shown in the table 7.3

Table 7 3: Sensory value of sliced mango

Status Harmonious flexibility and toughness

Color Has a light yellow color, a little dark

Odor Characteristic aroma of ripe mango

Taste The harmonious sweet and sour taste of ripe mango

Microbiological criteria according to Decision No 46/2007/QD-BYT dated December 19, 2007 are shown in Table 7.4

Table 7 4: Microbiological criteria of sliced dried mango

Order Target name Unit Maximum levels

1 Total aerobic bacteria CFU/g CFU/g

6 Total number of yeast – mold spores

Size of slices of dried mango (cm): length 8.3 - 8.7; width 2.6 – 3.3; 0.3 - 0.6 thickness Check the outer shape, tightness of the package

Determination of physical parameters: humidity, temperature, etc

Determine the basic chemical parameters of the product: concentration of dry matter, acidity,

The content of heavy metals in the product must meet the allowable standards

Heavy metal content According to QCVN 8-2: 2011/BYT and TCVN 3572:1981 is shown in table 7.5

Table 7 5: Indicator of heavy metal content

Prepare a test sample for storage containers as follows: a Wash utensils with soap and avoid repeated use of clean water, do not come into contact with the surface of food containers after washing b Fill with 4% (v/v) acetic acid solution, leave for 24 hours at room temperature (record amount of solution before analysis) c After 24 h, stir the 4% acetic acid solution and take a quantity sufficient for quantitative analysis of Sb, As, Cd, Pb

Method for determining Arsenic content: TCVN 7770: 2007 (ISO 17239: 2004): Vegetables, fruits and vegetable and fruit products - Determination of arsenic content - Atomic absorption spectrometric method for hydride release

Method for determining Lead content: TCVN 7766: 2007 (ISO 6633: 1984): Vegetables, fruits and vegetable and fruit products - Determination of lead content - Non-flame atomic absorption spectrometry method

Order Target name Unit Maximum levels

1 Arsenic (As) content mg/kg 1,0

2 Content of Lead (Pb) mg/kg 2,0

3 Cadmium (Cd) Content mg/kg 0,05

4 Mercury content (Hg) mg/kg 0,05

5 Copper content (Cu) mg/kg 5,0

6 Iron content (Fe) mg/kg 5,0

7 Zinc content (Zn) mg/kg 10,0

Method for determining cadmium content: TCVN 7768-1: 2007 (ISO 6561-1: 2005): Vegetables, fruits and vegetable and fruit products - Determination of cadmium content Part 1: Atomic absorption spectrometric method using graphite furnace

Method for determining mercury content: TCVN 7604: 2007 (AOAC 971.21): Food Determination of mercury content by flameless atomic absorption spectroscopy

Residues of pesticides and other compounds are consistent with Decision No 46/2007/QD-BYT dated December 19, 2007 of the Ministry of Health and current regulations

➢ Nutritional value of the product

The product nutritional value of dried mango slices is shown in Table 7.6

Table 7 6: Nutritional value of dried mango slices in 100g product

Occupational safety - factory hygiene and fire prevention

The issue of occupational safety must be focused, it is included in one of the leading

142 emulation standards that will promote labor productivity and reduce product costs

One of the best methods of labor insurance is a matter of organization and discipline

In the factory, it is necessary to regularly disseminate occupational safety techniques and at the same time educate everyone to have a sense of occupational safety in production The organization of labor, reasonable arrangement and improvement of the technical level of the production line also contribute to reducing occupational accidents

In standing positions, it is necessary to have a table of machine operation rules Workers operating the machine need to be fully equipped with labor protection The moving parts of the machine need to be covered to avoid accidents Factory workers must wear gloves and boots

7.3.1.1 The main cause of accidents

Labor organization and the relationship between departments are not tight

Labor protection equipment is lacking or not safe

The workers' sense of discipline is not high

Operating machinery and equipment not in accordance with technical procedures

Skill level and technical mastery of workers are still weak

The equipment and machinery are not well equipped and unreasonable

7.3.1.2 Safe working with hot or high temperature equipment

To ensure labor safety, workers working at these equipment should pay attention to comply with labor protection conditions and some of the following actions:

− Note that the solution must flood the steam pipe, do not let hot water overflow the device

− Observe and adjust the safety valves, at least 2 times each shift

− For steam equipment, do not let the steam pressure exceed the allowable range of the device, which can easily cause explosion or break the device

− Before putting steam into the pot, open the valve to remove all condensate

For boiler workers: in service of production, it is necessary to have a labor safety regime when working at high pressure of the boiler and pay attention to fire problems

7.3.1.3 Occupational safety when operating machinery

When operating, workers must check all parts, see if there is any damage, if necessary, promptly repair and avoid accidents while working

Absolutely perform their functions properly, each worker on the machine must take full responsibility for his or her own machine Need to avoid the phenomenon of asking others to watch for you, accidents will happen due to not understanding the operating principles of the machine

Regularly check the insulation covers, check the connections to the equipment When machinery has electrical damage, production workers are not allowed to repair it themselves

Rules on electricity use need to be established and widely disseminated among workers To ensure safety from lightning, place lightning rods in high places in the factory such as water towers, substations Protective lamp lines must be at least 3m or more from the tree line and need to be covered with wire

For workers in the main workshop, it is necessary to have a reasonable lighting regime for night shift production because workers at the raw material handling stages require a high degree of discrimination in color and status

Industrial hygiene is a necessary issue and a strict requirement for food factories in general and vegetable and fruit factories in particular because industrial hygiene affects product quality environmental pollution, affecting workers' health, manufactured goods are eaten immediately, or left for a long time after preservation Besides, the product is

144 made for long-term storage, if it is contaminated with microorganisms, it will seriously damage it, it will affect the quality of the product, reduce its use value and affect the health of consumers if it contains poison and damage the reputation of the factory For workers working directly, in contact with food products, the process of microbial contamination is partly brought in by workers Therefore, the hygiene stage must pay attention to personal hygiene

Industrial hygiene in the factory needs to follow the correct technological process, comply with the factory's rules, in order to improve the quality of products and improve working productivity To ensure the hygiene of the factory, it is necessary to pay attention to:

7.3.2.1 Personal hygiene requirements of workers

When working, must wear protective clothing, for direct workers must have a white coat When working, it must be neat and clean, the hair (female workers) must have a hat to cover the hair, and the nails must be cut short Serious working style After the break, before going into production, they must clean their hands and feet before entering the workshop

The worker's workplace is clean and regularly cleaned before starting work before taking a break in the middle or at the end of the shift

Implement well the regime of health check for workers every 6 months, do not let sick people, especially those with infectious diseases, enter the production area

7.3.2.2 Requirements for cleaning machinery, equipment, working tools, water supply and drainage

Machines, equipment and tools are in direct contact with the product Therefore, for machinery and equipment, the following hygiene requirements are required:

− Working machines such as conveyors, buckets, gooseneck conveyors, etc need to be cleaned periodically and regularly before the shift, mid-shift, and end-shift

− Must clean, wash and clean, especially the operating parts that come into direct contact with the product

− Working tools such as: working tables, knives, cutting boards, trays must be

145 cleaned and arranged neatly before and after work, tin knives, aluminum trays need to be disinfected before each shift, after every shift After 1-2 hours, flush the table and rinse with hot water once

− Machines and manufacturers must clean every day, at the end of each production shift, because the product is easy to be penetrated by microorganisms and pollute the factory

− Work places that require high hygiene such as: peeling, removing seeds need to have a good drainage place to avoid moisture and dust

Workshop floor: scrub with Ca(OH)2 or soapy water and rinse with water to avoid slipping and the drainage system must be absolutely guaranteed

Ensure the level of ventilation and air conditioning to help workers work with high productivity and good product quality If the water supply is not enough, the hygiene regime is not guaranteed, and if the water quality is not satisfactory, the product quality will be reduced Plants need to plant a lot of trees in the area and arrange ventilation in summer and airtight in winter

Therefore, the water supply must meet the required quality and quantity for each working part The sewage system is located underground to avoid contamination of the products, then leads to the main sewer system of the province

7.3.2.4 Waste treatment of the production process

Production waste such as mango peels and mango seeds are quickly moved out of the factory and sold to nearby processing plants This must be closely contracted and resolved in a timely manner to avoid backlog causing microbial contamination of the product

Wastewater contains many organic impurities, so microorganisms are easy to grow, causing pollution to the living environment of humans Therefore, the problem of wastewater treatment is very important for the factory

Currently, there are many methods of wastewater treatment and each method has its

146 own advantages The plant treats wastewater by a method that uses both mechanical measures such as pre-filtration tanks, settling tanks and aeration tanks to create conditions for aerobic microorganisms to use up all the waste before discharge into the environment