Experiment Report Process & Equipment In Food Technology Iii.pdf

lOMoARcPSD|38592384 HA NOI UNIVERSITY OF SCIENCE AND TECHNOLOGY SCHOOL OF BIOLOGY AND FOOD TECHNOLOGY ***** EXPERIMENT REPORT PROCESS & EQUIPMENT IN FOOD TECHNOLOGY III Instructor: Dr Le Ngoc Cuong Performed by students: Nguyen Hai Yen Code ID: 20201334 Class: CTTT- Food Technology 01 – K65 Class code : 726609 HANOI 02 /2023 Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Full name: Nguyen Hai Yen MSSV: 20201334 Grade: 726609 BF2573E: EXPERIMENT HEAT PUMP DRYING I PURPOSE OF EXPERIMENT 1 Be familiar with and master the process of operating the experimental heat pump drying equipment 2 Determine the relationship between the moisture content of the material and the drying time (drying curve) 3 Determine the relationship between the moisture content of the material and the drying rate (drying rate curve) I DEVICE AND OPERATION PRINCIPLE 1 Describe a device 2 Air conditioner construction - Compressor: sucks all the refrigerant generated in the evaporator while maintaining the necessary pressure for low-temperature evaporation and Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 compressing the vapor from the evaporator pressure to the condenser pressure, pushing it into the condenser - Hot rig (condenser): is a heat exchange device between a condensing refrigerant on one side, and a cooling medium on the other side (water or air) The job of the condenser is to release the heat of the condenser to the environment - Throttle valve: change flow volume, flow velocity increases, pressure decreases - The evaporator (evaporator): is a heat exchange device between the refrigerant on one side and the medium to be cooled on the other The job of the evaporator is to collect the heat of the cold environment to supply the refrigerant to boil at a low temperature 3 Draw a schematic diagram of the device Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Heat pump drying equipment according to the above principle consists of the following components: I – Calorife, in this calorife there are indoor units to separate moisture and outdoor units to heat TNS II – Drying chamber 3 III, IV – Inlet and outlet air channels of the drying chamber V – Technical box, where the compressor, expansion valves, outdoor unit and auxiliary indoor unit are stored 4 Working principle - Refrigerant in the form of gas through the compressor is compressed to condensing pressure, then passed through the outdoor heat exchanger for cooling At that time, the refrigerant will be completely condensed into a liquid form (exothermic process) - Next, the liquid in liquid form passes through the throttle valve to regulate the flow - After that, the refrigerant continues to pass through the evaporator evaporator - That vapor continues to enter the compressor The four-stage continuous circulating heat pump cycle: Stage 1-2: adiabatic compression: the process of compressing refrigerant from low pressure, low temperature to input pressure, high temperature in the compressor Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Stage 2 – 3: Isothermal condensate: the refrigerant state changes from superheated steam to boiling water or moisture through the process of discharging heat out by the condenser (outdoor unit) Stage 3 – 4: Throttle, constant enthalpy: Refrigerant is depressurized as it passes through the throttle, this process does not change the enthalpy of the refrigerant Stage 4 – 1: Isothermal evaporation: Refrigerant state changes from moisture to dry saturated steam or superheated steam through heat recovery by evaporator (indoor unit)  Advantage:  The air temperature can only be maintained at ambient temperature or below, so the ability to retain colors, flavors and vitamins is good → suitable for drying materials with poor heat resistance  It is possible to adjust the temperature of the drying agent depending on the requirements and heat resistance of each product by changing the heat capacity of the condenser  Energy saving by using both outdoor and indoor unit energy to dry and dehumidify, high heat use efficiency  The capacity is quite large  Because the equipment is designed in a circular motion, the raw materials will be in direct and continuous heat contact, avoiding the phenomenon that some materials are too dry and can become charcoal while others are not can't dry  The device is designed sustainably and occupies a small area, the structure is simple and compact, so the cleaning and cleaning equipment is simple and convenient  Environmental protection, safe operation  Defect:  The drying time is usually quite long because the difference in water vapor pressure between the drying material and the drying agent is not large  There must be a solution to defrost after a period of work II Practice drying vermicelli Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 TABLE OF EXPERIMENTAL CALCULATION RESULTS DATA SHEET No Drying Drying Amount of Moistu Humidi Drying Time (minutes chamber materia moisture e mass y of speed ) temperatur l weight evaporate (g) materia (g/min) e ( C) (g) d W (g) l W(%) 1 0 45 264.4 0 89.5 33.85 0 2 10 45 252.1 12.3 77.2 30.62 1.23 3 20 45 241.0 11.1 66.1 27.43 1.11 4 30 45 231.1 9.9 56.2 24.32 0.99 5 40 45 215.9 15.2 41 18.99 1.52 6 50 45 202.0 13.9 27.1 13.42 1.39 7 60 45 192.1 9.9 17.2 8.95 0.99 8 70 45 183.9 8.2 9.0 4.89 0.82 9 80 45 178.5 5.4 3.6 2.02 0.54 ten 90 45 174.9 3.6 3.6 2.06 0.36 Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 1 Weight of moisture in material In there: - Weight of moisture at time I, g - VLS volume at time i, g - Dry weight, expressed as mass of material after drying (referred to as absolute dry weight), g 2 Amount of moisture evaporating In there: , -VLS mass at time i and i+1, g 3 Humidity of Drying material In there: - humidity of VLS at time i, % 4 Drying speed In there: - time interval between two VLS weighings, minutes Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 III Graphs and Comment 1 Graph of drying curve graph shows the dependence material moisture at drying time 40 35 30 25 W (%) 20 15 10 5 0 0 10 20 30 40 50 60 70 80 90 100 Time (minutes)  Comment: The moisture content of the material decreases over time 2 Graph of drying rate curve graph shows the dependence drying rate on drying material moisture 1.6 1.4 1.2 1 Drying 0.8 0.6 0.4 0.2 0 0 5 10 15 20 25 30 35 40 W (%)  Comment: The more moisture, the faster the drying speed and vice versa Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Full name: Nguyen Hai Yen MSSV: 20201334 Grade: 726609 BF2573E: EXPERIMENT EXTRACTION I Preamble Extraction is the process of separating one or more solutes from a liquid or solid by another liquid called a solvent In the content of this experiment, the solid- liquid extraction process will be performed II Experiment purpose 1 Familiarize yourself with equipment used for extraction: soxhlet, rotary vacuum evaporator 2 Determine the content of components to be extracted and compare the efficiency when using different solvents III Experimental diagram Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 IV Experimental steps 1 Check the experimental equipment system according to the diagram, install the equipment 2 Prepare measuring tools: Scales, measuring cups , solvents, samples to be extracted 3 Add the extract and solvent to the Soxhlet 4 For cooling water through the condenser tube, turn on the heating (depending on the solvent that has a reasonable heating value) 5 Start calculating extraction time 6 After completing the extraction process, the evaporator is rotated under vacuum to separate the solvent and components to be extracted 7 Record the data in the table 8 After taking all the data, turn off the machine, clean the experimental site, report the experimental results to the instructor Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Table 1: Table of experimental results Solvent is n-hexane Dry sample mass: 50.1g Solvent amount 60g Extraction temperature 60 0 C Extraction time 2 hours Amount of extracted constituents recovered 16.8g V Compare test results => Result: - Due to insufficient experimental conditions, only 1 experiment was performed with n-hexane as a solvent - Based on the theory, it can be predicted that the extraction efficiency in experiment (1) with n-hexane as a solvent will be higher than in experiment (2) with water as a solvent, which means that the time for the experiment will be higher Experiment (2) will take longer => Discussion: - Because the extracted product is oil (non-polar), the use of organic solvents (non-polar) will be easier to dissolve the product than water (polar) - However, if water is used as a solvent, the oil and residual water will separate in the recovered product -> easy for product separation - n-hexane is a volatile compound (boiling point 68.7 degrees Celsius), so the amount of hexane left over after production and after heating during home cooking (usually >160 degrees Celsius) Is negligible Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 Full name: Nguyen Hai Yen MSSV: 20201334 Grade: 726609 BF2573E: EXPERIMENT Exhaust gas recirculating convection drying I Theory: Drying is the process of removing some or most of the moisture present in a damp object The drying process is very complicated and unstable, in which many processes occur at the same time such as heat transfer from the drying agent to the drying object, heat conduction in the drying object, evaporation of moisture, and moisture conduction from the inside to the surface surface of the drying object, transferring moisture from the surface of the object to the drying medium The above processes all follow the process of moisture transfer During the drying process, the moisture content of the dried object continuously changes in a decreasing direction and is divided into 3 stages: - The first stage: the stage of heating the drying object to the evaporation temperature of the moisture - The first stage (the stage with constant drying speed): mainly evaporates the free water in the drying object The vapor rising from the surface of the drying object is saturated steam, the heat of vaporization is exactly equal to the heat of vaporization of free water - The second stage (phase of drying speed is gradually decreasing): when the internal moisture transmitted to the surface of the drying object is less than the amount of moisture that can be evaporated on the surface of the material This period lasts until the drying material reaches equilibrium moisture content Drying curve: The curve representing the change of the moisture content of the dried object with the drying time is called the drying curve: w = f(t) The function graph f(t) depends on many factors such as the type of bond between the water and the drying material, the shape, size and characteristics of the drying object, the method and the drying mode, but they all have the same general form as illustrated in figure 1 Drying speed curve: The drying rate curve represents the relationship between the drying rate and the moisture content of the drying material, obtained by derivating the drying curve with respect to time: dw/dt = f(w) Figure 2 illustrates a type of drying rate curve In the first drying period, the drying rate is constant, so the graph of the function Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 f(w) is the line segment AB parallel to the horizontal axis The representation of the second stage of the drying process has a complex shape, depending on the structure of the drying material and the type of bond between the moisture and the dry matter in the dryer w dw/dt wA A B A wB B t0 t1 t wc wB wA wđ w Figure 1 Drying curve Figure 2 Drying rate curve II Experiment purpose: - Be familiar with and master the operating process of convection drying experiment equipment with exhaust gas recirculation - Determine the relationship between the moisture content of the material and the drying time (drying curve) - Determine the relationship between the drying speed and the moisture content of the material (drying rate curve) III Experimental diagram and working principle of experimental equipment: 11     On 12 Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 1 23 4 9 8 7 5 6 10 1 Scales 5.Fan 9 Flanges 2 Drying material 6 TNS outlet 10 Bracket 3 Drying chamber 7 Caloriphe 11 Total Atomat 4 Air intake door 8 Control cabinet 12 Control switch Rules of work: The outside air is sucked in by fan 5 through door 4 and then heated in an electric caloriphe 7 Air temperature control thanks to the contact thermometer system The wet material is placed in trays placed in a frame of the drying chamber The frame is hung on the weighing pan 1 Observe the change in the mass of the dried material on the needle of the balance Adjust the amount of exhaust air thanks to the screened door 6 IV Test sequence: - Step 1 Weigh the material to be dried (vegetables, tubers, fruits) Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 - Step 3 Observe and check the experimental system according to the diagram - Step 4 Open the fan and close the heat transfer bridge to increase the caloriphe heat - Step 5 Wait until the drying temperature (drying agent) is stable (dry at a certain temperature, then adjust the contact thermometer) before adding the material and reading the reading on the scale - Step 6 Read and record the reading on the scale every 5 minutes for moisture evaporation Continue doing this until the reading on the balance does not change after 3 measurements, then stop the experiment - Step 7 Turn off the calorific circuit breaker, wait 10 minutes and then turn off the fan Take out the dried material to observe and weigh the material Record the data obtained and report to the instructor - Step 8 Clean up the experiment place before leaving V Calculation 1 Initial amount of moisture in the material: g = G - G k (g) Where: G - Weight of wet material, g G k - Absolute mass of dry material, g 2 The amount of moisture evaporated: W i = Gi - G i-1 , (g) Gi , G i-1 : To be mass of material for time i and i-1 3 The amount of moisture contained in the material: W' = g - (g) 4 Material moisture: W = W'.100 / G , (%) Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 VI Table of experimental data and calculation results: Experimental data table Calculation results Amount Amount Drying of of Moisture Drying No Time chamber Scale moisture moisture of drying speed t(min) temperat indicato r G (g) evaporat in the ing drying material dW Fd ure ( 0 C) material W (%) (g/min) W i (g) W' (g) 1 00 80 0.350 0.000 0.125 35.7 0 2 05 80 0.325 0.025 0.100 30.8 0.005 3 10 80 0.300 0.025 0.075 25.0 0.005 4 15 80 0.275 0.025 0.050 18.2 0.005 5 20 80 0.250 0.025 0.025 10.0 0.005 6 25 80 0.235 0.015 0.010 4.3 0.003 7 30 80 0.225 0.010 0.000 0 0.002 8 35 80 0.225 0.000 0.000 0 0 9 40 80 0.225 0.000 0.000 0 0 Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 VII Report: 1 Graph of drying curve: The drying curve graph shows the dependence material moisture at drying time 40 35 30 25 W (%) 20 15 10 5 0 0 5 10 15 20 25 30 35 40 45 t (minutes) Comments : - The moisture content of the drying material decreases with time - Towards the end of the drying period, the drying speed decreases due to the decrease in free moisture, increased binding moisture - The final amount of moisture in the drying material is zero compared with the original dry material (relative only) In fact, the material is still moist after drying, especially the bonding moisture - If drying continues for a long time, the amount of moisture will still decrease, but the quality of the material will be changed (possibly burning) 3 Graph of drying speed curve: Downloaded by Huyen DO (tailieuso.16@gmail.com) lOMoARcPSD|38592384 The drying curve graph shows the dependence drying rate and drying material moisture 0.01 0.01 0 Drying 0 0 0 0 0 5 10 15 20 25 30 35 40 W (%) Comment: - The higher the humidity, the faster the drying speed and vice versa - The drying speed in the first stage increases rapidly and stabilizes in the middle, then gradually decreases at the end of the period Because in the early stage, the amount of free moisture is large and there is a large amount of surface moisture, so the moisture drainage is quick and easy, the moisture drainage rate is reduced due to the decrease in free moisture, and the bonding moisture is increased Downloaded by Huyen DO (tailieuso.16@gmail.com)