4.1. Overview of Tan Quang Cement Factory belonging Tan Quang Cement Joint Stock
4.1.3. Diagram flow production technology of Tan Quang cement factory
Production technology in Tan Quang cement factory is production technology employing the dry method with a rotary kiln system have heat exchange tower and decomposition chamber. The level of high automation, the modern facilities are applied to ensure stable production, high productivity product quality reached economic efficiency.
Technology referred to above, have been applied in many countries around the world, have the advantage of fuel saving by advantage of a radically heat from stage cement kilns with heat exchange tower, achieving efficiency high heat, heat advantage of redundancy (for drying, crushing coal). Transportation of fuel between the categories in the factory is also carried out in the pneumatic tube work under positive pressure seal ensures leak avoid pressure loss and material spillage. Therefore this technology is very friendly with environmental, reality has shown in the rotary kiln cement factory today (Ninh Binh, Ha Tien, La Veranda ....) Environmental issues improves our already very significantly. The advantages of rotary kiln on environmental issues is also the reason for our country's cement industry gradually replacing the blast furnace cement the factory capital are contaminated, consuming more energy and productivity as well as low quality.
The main stages of the technological line for cement production of Tan Quang cement factory include:
Table 4.2. The main production stages Ordinal
numbers
Code number stages Name stages
1 111 Limestone break
2 112 Warehouse limestone
3 113 Clay break
4 114 Warehouse clay
5 115 Receive and materials break
6 116 Warehouse of materials
7 121 Quantitative material grinding
8 122 Material grinding
9 131 Homogenous silo
10 141 Preheater
11 142 Kiln
12 143 Cooler clinker
13 150 Coal grinding
14 161 Silo clinker
15 162 Quantification of cement grinding
16 163 Cement grinding
17 171 Silo cement
18 172 Packing and Cement taken
19 173 Port cement
(Source: Report environmental impact assessment, Tuyen Quang, 2008)
Hot wind
Coal Oil DO keep fire
Hot wind Wind
Dust recovery
Additives gypsum and slag …
Dust recovery Dust recovery
Figure 4.5. Diagram flow production technology
4.1.3.2. Notes to the production technology
Filter dust canvas bag Quantification of cement
grinding 150t/h
Silo cement 10000 tons x 2
Cement taken Packing machine
100t/h Filter dust
canvas bag
Filter dust Electric Coal grinding
20t/h
Other materials gypsum, slag, pyrite Clay mine,
clay break 120t/h Limestone mine,
limestone break 4000t/h
Warehouse of materials Warehouse limestone
23000 tons
Warehouse clay 10000 tons
Quantitative material grinding stand 200t/h
Homogenous silo 10000 tons
Filter dust canvas bag - Kiln rotary 2500t/h
- Preheater
Cooler clinker 61.2m2
Silo clinker 20000 tons
Limestone exploited in mine Trang Da small size than 1000mm is transported to the dam station limestone located on the hill next to the mine (vehicle use with load 32-36 tons). At the dam station limestone, limestone will be processed by hammer crusher (capacity 400 t/h) to the size <70mm. Then it will be transported to the factory by conveyor systems are installed to capture dust sealed switch on limestone warehouse in the factory. Equipment dust cleaner bag is used at the station to limit the amount of dust released into the environment.
Warehouse limestone are builded style circular diameter ray 80m, tankage about 23000 tonnes ensure reserves enough material limestone for about 7-8 days producer. At the warehouse limestone, a spreaders material type crane yield 450 t/h is used to limestone piled form donuts around warehouse.
b. Preparation material clay
Clay in mine Trang Da after the exploit size <500 mm are transported to the dam station clay by trucks. Here clay is processed further to size <70 mm by two axis helical masher yields about 120 tons/h and conveyor transporting the clay warehouses.
At stations clay dam, the precipitators were installed to limit the environmental dust and avoid the effects of natural to this material.
Warehouse clay long form with a width 27m and length 144m equipped with equipment material spreader type car spreader yield 150 t/ h sprayed into 2 material piles, each piles approximately 5000 tonnes for 7.5 day production.
c. Material
+ Dust coal Quang Ninh, sand was transferred to the port by barge will be unloaded by crane cable onto the conveyor and transport to fuel storage. Dust coal Khanh Hoa Thai Nguyen was transferred to factories by trucks.
+ Additives include gypsum, slag, pyrite transported to the factory by car and after machining by hammer crusher 90 tons / h machining to particle size <25 mm.
To collect dust environmental protection, a dust filter fabric bag is also equipped in material and fuel warehouse.
d. Material and fuel warehouse.
Warehouse aggregate have form long with size 46.5m wide and 150m long.
Material and fuel are spreaders capacity of 100 t / h scattered in heaps along the warehouse include:
+ Gypsum: 2400 tons + Furnace slag: 4600 tons + Coal dust: 2 x 3000 tons + Pyrit: 1300 tons
+ Sand: 1500 tons
The transport from the warehouse is done by dispenser raw materials and transporting to machines mill cement, machines mill raw material or machines mill coal.
e. Quantification mill material
The raw material, limestone, sand clay and pyrite from the warehouse are transported by conveyor to the bunker of quantitative station:
+ Bunker limestone: 200 tons (reserve 1.3h) + Bunker clay: 70 tons (reserve 1.7h)
+ Bunker sand: 75 tons (reserve 6.6h) + Bunker pyrite: 75 tons (reserve 23h)
From the bunker, raw materials get quantification scales weight control every kind of materials into material mill system.
f. Mill material:
Crusher material is equipment main of material crushing stages. At Tan Quang cement factory, material crushing equipment is crusher vertical roller material to utilize the advantages as powder drying capability with high humidity, low power consumption and is capable of segregating high.
Capacity selection would be about 20 t / h. After fine crushing, blending is gathered in the cyclone and the air slide switch to bucket lift to load the aggregate homogenization silos.
At crushing equipment, exhaust gas after the preheater will be utilized for drying batches. A burner by DO oil burners would be used in case of boot rotary kiln or batching greater humidity levels specified.
Dust arising from crushing equipment being collected dust by electric precipitators of the whole system whole filter and crushed material. Dust revocation will bring back the preheater.
g. Preheater and kiln
Preheater and kiln consists preheater chamber decomposition rotary kiln biggest productivity gain in 2700 tonnes clinker / day.
Preheater consists of a branch five floors cyclone have biodegradable chamber combustion entirely by coal dust 4aKH and 4aHG accounted for about 55-60% total coal use and offered air to burn bran from hot air of the device notation cooling through wind pipe.
Rotary kiln has an inner diameter 4m, length 60m and the tilt 3.5%, is placed on the bracket in the concrete. Fuel used for rotary kiln are coal dust 4aKH and 4aHG (accounting for 40-45% of total coal use). Waste gas from the rotary kiln and the chamber decomposition temperature of about 120-150°C be directed to utilize as heat for the drying process crushed batching.
To ensure stable operation conditions of the rotary kiln and the chamber decomposition, the monitoring system emissions components be installed at road out of the preheater. The monitoring indicators are O2, CO, NO.
h. Clinker cooler
Clinker out of the kiln with a temperature of about 1371°C is cooled in cooling devices type credited with area 61.2m2, yield 2500 tons of clinker/day. Here clinker is cooled to a temperature of less than 65°, processed to a particle size of about 25 mm and transported to the silo clinker.
During operation of the cooling equipment incurred large amounts of dust. The amount of dust generated will be recovered utilize as materials by the dust filter electricity with a capacity of 315.000m2 / h.
i. Coal crush
To crush coal initial humidity large (> 9%), roller mill standing capacity of 20 tons / h was selected because of advantages in terms of energy saving, high drying ability and low maintenance costs. Heat-drying agent used for the millis emissions from electrostatic precipitators of clinker cooling area. Here coal is contained in the 50 ton Bunke (two units) connected to devices quantitative crude coal have valve closed.
Fine coal is recovered through dust filter sleeve. Coal dust recovery will be given up
j. Quantification of cement grinding
Clinker from silo clinker, gypsum and blast furnace slag from fuel material warehouse get equipment raw withdrawn and transport by conveyor loaded directly into bunke of quantitative cement grinding station:
+ Bunke clinker: capacity 200 tons
+ Bunke blast furnace slag: capacity 100 tons + Bunke gypsum: capacity 100 tons
The bunker through scales quantitative will get to machines mill cement through a grinder before using rolling machines Φ1400 x 1000 combined with sealed ball mill capacity of 150 tons / h, the product has fineness reached 32000cm2/g. The entire cement with satisfactory the fineness will follow the gas stream enters the filter bag 210.000m3 / h to gather and dedusting of cement grinding system then under air slide taken to two cement silos Φ18m , high capacity 10000 tons 48m have put at the bottom and removable door operated air slide taken to dispensing system. At the time of arising dust will be the installation of dust collection equipment to recover the form of bags of cement.
Cement not reach the fineness will be put back on the ball mill grinding to perform again.
k. Bagged and shipped cement
The plant will be equipped with two bagging lines and cement bags for automotive synchronous with two packaging machine 8 taps productivity 90-100t/h.
To mitigate dust into the environment, ensure the working environment of workers while minimizing wastage of cement leakage, the cloth bag filter was installed at the point of cement dust.
The cement leave also made by a cement line parallel leave cement sack line yield of 120t/h.