Production Process of Coking Plant
There are 9 production workshops in the coking plant, which are Coal Preparation Workshop, No.1 Coking Workshop, No.2 Coking Workshop, Coke Transportation Workshop, No.1 Recycling Workshop, No.2 Recycling Workshop, Thermal Workshop, Repairing Workshop and Refining Workshop. The main production workshops of the coking plant: coal preparation workshop, coking workshop, gas purification workshop and its public and auxiliary facilities, etc. The main production facilities of each workshop are shown in the following table:
Serial No.
System Name
Main Production Facilities
1
Coal Preparation Workshop
Coal silo, coal blending room, crusher room, conveyor system, coal sample room
Coal Preparation Workshop
2
Coking plant
Coal tower, coke oven, coal loading facility, coke pushing facility, coke stopping facility, coke quenching tower, coke screening and transporting section (including coke table and coke screening building)
3
Gas purification plant
Cooling and drumming section (including fan room, primary cooler, electric tar catcher, etc.); de-ammonia section (including ammonia washing tower, ammonia evaporation tower, etc.); and ammonia removal section (including ammonia washing tower, ammonia evaporation tower, etc.). ammonia washing tower, ammonia evaporation tower, ammonia decomposition furnace and other facilities); crude benzene section (including final cooler, benzene washing tower, de-benzene tower and other facilities)
4
Public and auxiliary facilities
Waste water treatment station, power supply and distribution system, water supply and drainage system, comprehensive water pump house, coal preparation and dedusting system, screening and transporting coke and dedusting system, laboratory and other facilities, refrigeration station and so on
3. Importance of cokemaking Significance
The coke obtained from high-temperature coking can be used as fuel and raw material for blast furnace smelting, casting, gasification and chemical industry; the dry distillation gas obtained in the process of coking can be recycled and refined to obtain a variety of aromatic hydrocarbons and heterocyclic mixtures, which are used for synthetic fibers, pharmaceuticals, dyestuffs, paints and national defense industries to be raw materials; the purified coke oven gas is a high-calorific-value fuel, and also a raw material for ammonia, synthetic fuels and a series of organic synthesis industries. Coke oven gas after purification is not only a high calorific value fuel, but also a raw material for ammonia synthesis, synthetic fuel and a series of organic synthesis industry. Therefore, high-temperature coking is not only an important way of comprehensive utilization of coal, but also an important component of the metallurgical industry.
Policy risk coal is one of China's most important energy in the national economy is in a pivotal position in the operation of the coking industry belongs to the national key industries. In order to establish a large-scale iron and steel cycle structure, in the important production base of iron and steel and coking coal production base construction and operation of modern large-scale coking plant in line with China's industrial policy and the direction of economic restructuring is also a prospect for the development of coking industry.
V. Preparation of Raw Coal
The production task of the coal preparation workshop is to provide the coking workshop with sufficient quantity and quality of coal that meets the requirements. The process flow is as follows: Raw coal → coal receiving pit → coal yard → bucket tank → coal distribution disk → pulverizer → coal tower.
1, coal reception and storage
Raw coal is generally transported from all over the world by car and train, and the raw coal of Handan Iron and Steel Coking Plant mainly comes from Kangzhuang and Guanzhuang in Xingtai, Fengfeng and Shanxi. When the car or train arrives, after positioning with the coal receiving pit, the coal is unloaded into the silo by the screw coal unloader, and when the feeding trolley opens the opening of the silo, the coal is transported to the specified position by the belt. Note: Each silo can only hold the same type of coal at a time.
In order to ensure the continuous production of coke ovens and stabilize the quality of coke oven coal, the coal should be unloaded in the coal yard by stacker according to the category of coal quality. Handan Iron and Steel Coking Plant coal preparation workshop with four kinds of gas coal, fat coal, coking coal and lean coal, according to the provisions of the stacked in the coal yard of the five zones.
2. Characteristics of coal raw materials and principles of coal allocation
①Gas coal Gas coal has a higher degree of coalization than long flame coal, and the molecular structure of the coal has more and longer side chains and higher oxygen content. In the process of pyrolysis, not only the side chain is broken from the condensed aromatic ring, but also the side chain itself is broken at the oxygen bond, so more colloid is generated, but the viscosity is small, the mobility is large, its thermal stability is poor, easy to decompose. In the generation of semi-coke, a large amount of volatile gases are decomposed, and the part that can be cured is small. When the semi-coke is converted into coke, it shrinks a lot and produces many cracks, mostly longitudinal cracks, so the coke is thin and fragile.
In coal blending, a high content of gas coal will make the coke less lumpy and less strong. However, with proper gas coal, it can increase the shrinkage of coke, which is easy to push coke, and protect the furnace, and at the same time, it can get more chemical products. Due to the large storage of gas coal in China, in order to reasonably utilize the resources of coking coal, as much gas coal as possible should be matched in coking.
②Fertilizer Coal Fertilizer coal has a higher degree of coalification than gas coal, and belongs to the medium degree of metamorphism. From the molecular structure, fat coal contains more side chains, but less oxygen, isolated from the air when heated to produce a large number of relative molecular mass of the liquid product, therefore, the number of fat coal colloid generated by the largest number of colloids, the maximum colloid thickness of up to 25mm or more, and has a good mobility, and thermal stability is also good. The generation temperature of fat coal colloid is 320℃, the curing temperature is 460℃, and the temperature interval in the colloid state is 140℃. If the heating rate is 3℃/min, the existence time of colloid is up to 50min, thus determining the strongest adhesion of fat coal, which is one of the basic coal types of Chinese coking coal. Due to the high volatility, the thermal decomposition and thermal condensation of semi-coke are more violent, and the final shrinkage is very large, so the coke produced has more class questions, deep and wide, and more transverse cracks, so it's easy to be broken into small pieces, and the abrasion resistance is poor, and the abrasion strength of coke produced by fat coal with high volatility is even poorer. Fatty coal alone coking, due to the number of colloidal bodies, and a certain degree of adhesion, expansion, resulting in pushing coke difficult.
In coal blending, the addition of fertilized coal can play a role in improving the adhesion, so fertilized coal is an important component in coking coal blending, and provides the conditions for more blending of coals with poor adhesion.
3 coking coal Coking coal is slightly higher than the degree of metamorphosis of fat coal, volatility is lower than fat coal, the molecular structure of the macromolecular side chain is less than the fat coal, the oxygen content is lower. Thermal decomposition of the liquid products produced less than fat coal, but the thermal stability is higher, the number of colloids, viscosity, curing temperature is higher, half coke shrinkage and shrinkage rate are smaller, so coking coke is not only a high abrasion-resistant strength, coke, cracks, and resistance to crushing strength is also good. In terms of coking, coking coal is the best coal that can produce high quality coke.
When blending coal, the amount of coking coal blending can fluctuate within a wide range, and can obtain high strength coke. So the purpose of blending in coking coal is to increase the strength of the coke.
④Lean Coal Lean coal has a higher degree of coalization, is a low volatility, moderately metamorphosed cohesive coal, generates less colloid when heated, and has a high viscosity. When coke is made alone, coke with large lump size, few cracks and high crushing strength can be obtained, but the fusibility of coke is very poor, and the abrasion resistance of coke is also poor. Matching lean coal in coal blending can improve the lumpiness of coke, which is more effective as a coal blending coal for coking.
In order to ensure the quality of coke and facilitate the production operation, coal blending should follow the following principles:
①The nature of coal blending is compatible with the coal pre-treatment process and coke-making conditions of the plant, so as to ensure that the quality of the coke smelted is in line with the stipulated technical quality indexes and to meet the needs of users.
②Coke oven production, pay attention not to produce excessive expansion pressure, in the end of the coking to have enough contraction, to avoid pushing coke difficulties and damage to the furnace.
③Take full advantage of the region's resources, so that transportation is reasonable, try to shorten the average distance of the coal source, to facilitate the deployment of vehicles and reduce production costs.
④As far as possible, appropriately allocate more high volatile coal to increase the yield of chemical products.
⑤ On the premise of guaranteeing the quality of coal, more gas coal and other weakly adhesive coals should be allocated, and as little as possible high-quality coking coal should be used, and efforts should be made to rationally utilize China's coal resources.
3. Coal blending process
When which kind of coal is needed, the coal is transported to the bucket trough through the belt by the stacker reclaimer, and the coal in the bucket trough is again sent to the blending pan through the belt to be blended according to the requirements. Handan Steel coking plant coal ratio is generally: 28% gas coal, 45% coking coal, 18% fat coal, 9% lean coal. In coal blending, Handan Iron & Steel Coking Plant adopts the use of nuclear scales for attenuation, through the conversion of signals transmitted to the computer for control. Signal control process is: Cs-137 → coal → (attenuation) ionization chamber → (inert gas) current → amplifier, transmission unit → weighing frequency signal, variable speed signal → computer system.
4, coal crushing
Handan Iron and Steel Coking Plant Coal Preparation Workshop of the raw coal fineness of 70% to 80%, meaning <3mm of coal material as a percentage of the total weight. Before entering the pulverizer, part of the coal that reaches the fineness of the raw coal is directly transported to the coal tower by the belt, and the other part of the coal that does not reach the standard is transported from the coal blending section to the pulverizer by the iron removing device after sucking the iron parts in the coal material, and then transported to the coal tower by the belt. In the Handan Steel coking plant's coal blending plant with a reversible hammer crusher, there is also a dust removal device next to the crusher.
5, coal preparation workshop equipment
Screw coal unloader: rotating mechanism, lifting mechanism, walking mechanism, frame.
Stacker and reclaimer: reclaiming mechanism, rotary mechanism, amplitude change mechanism, cantilever belt conveyor, tail car, traveling mechanism.
Bucket chute; South bucket chute for 1#-4# coke ovens There are 8 warehouses 500 tons per warehouse; North bucket chute for 5#-6# coke ovens, there are 8 warehouses 500 tons per warehouse.
Coal distribution pan: disk, scraper, plus or minus sleeve, reducer, motor.
Crusher: rotor, hammer head.
Six, coking
The so-called high-temperature coking, is the coal in the isolation of the air heated to 950-1050 ℃, through the drying, pyrolysis, fusion, adhesion, curing, contraction and other processes to finally get coke.
1, coke production process
The coal delivered by the coal preparation workshop is loaded into the coal tower, and the coal loading trucks pick up the coal from the coal tower according to the operation plan, and then load it into the carbonization room after measurement. In the carbonization room, the coal material undergoes a coking cycle of high temperature dry distillation to make coke and produce barren gas.
After the coke in the carbonization room matures, it is pushed out by a coke pusher and introduced into the coke quenching truck by a coke stopping truck, which is towed by an electric motor truck to the coke quenching tower for quenching the coke by spraying water. After coke quenching, the coke is unloaded onto the cool coke table, cooled for a certain period of time and then sent to the coke screening section, where it is screened and stored according to the level for transportation.
Desert gas produced during the dry distillation of coal in the carbonization room is gathered at the top space of the carbonization room, and enters the gas collecting pipe through the rising pipe and bridge pipe. The gas, which is about 700℃, is cooled down to about 90℃ by ammonia spray in the bridge pipe. The tar etc. in the barren gas is condensed down at the same time. The gas and the condensed tar are sent to the gas purification plant through the suction pipe together with the ammonia.
The coke oven gas for coke oven heating is brought in by external pipeline overhead. After preheating, the coke oven gas is sent to the coke oven basement, and through the lower nozzle, the gas is sent to the bottom of the combustion chamber vertical fire road and combusts with the air entering from the exhaust gas exchange opener. After combustion, the exhaust gas passes through the hole at the top of the combustion chamber and enters into the combustion chamber with falling airflow, and then passes through the heat storage room, and the lattice earns part of the sensible heat of the exhaust gas is recovered, and then it is discharged into the atmosphere through the small flue, the exhaust gas exchange opener, the sub-flue, the total flue, and the chimney.
2, coke oven structure analysis
The changes and development of the coke oven structure is mainly to better solve the coke cake high to the long direction of heating uniformity, energy saving, reduce investment costs, improve economic efficiency. In order to ensure the quality and yield of coke and gas, not only need to have the right coal ratio, but also need to have good external conditions, and reasonable coke oven structure is used to ensure the means of external conditions. For this reason, the coke oven structure needs to be analyzed from all parts of the coke oven. Handan Iron and Steel Coke Plant uses JN43-58-II type coke oven and JN43-80 type coke oven.
Modern coke oven body is the uppermost part of the roof, the top of the roof for the configuration of the combustion chamber and carbonization room, the lower part of the furnace body has a heat storage room and connect the heat storage room and combustion chamber of the ramps area, the lower part of each heat storage room of the flue small flue through the exchange of the opener and flue connection. The flue is located in the foundation of the coke oven or on both sides of the foundation, and the end of the flue leads to the chimney. Therefore, the coke oven consists of three chambers and two zones, i.e. charring chamber, combustion chamber, heat storage chamber, ramp zone, roof zone and foundation part. Because JN43-80 type coke oven is based on JN43-58-II type coke oven, through many years of production practice, and further refinement and improvement, so the following JN43-58-II type coke oven as an example of the coke oven of the above part to do the following analysis.
1) Carbonization room
Carbonization room is to receive coal and the charging of coal to isolate the air for dry distillation of coke chamber, generally made of silica refractory masonry. The charring room is located between the two sides of the combustion chamber, the top by 3-4 coal holes, and 1-2 export distillation gas rising pipe, it is lined with refractory at both ends of the cast iron furnace door. JN43-58-II coke oven charring room size is divided into two kinds of width, that is, the average width of 407mm and 450mm in two forms, the charring room height of 4300mm, the length of the whole 14080mm, the effective length of 13350mm, the charring room height of 1300mm, the effective length of 13350mm, the charring room length of 13350mm, the charring room length of 13350mm, the charring room length of 13350mm. The total height of the carbonization room is 4300mm, the total length is 14080mm, the effective length is 13350mm, and the effective area of the carbonization room is 21.7m3, and the heating level is 800mm.
2) Combustion room
The combustion room is located on both sides of the carbonization room, and it is the place where gas is burned, and the gas and the air are mixed and burned, and the heat produced is transferred to the wall of the furnace, and it indirectly heats up the coal in the carbonization room, and carries out high-temperature drying distillation for it. The combustion chamber is generally built with silica bricks.The width of the combustion chamber of JN43-58-Ⅱ type coke oven is 736mm and 693mm (including the wall), and the wall is silica bricks with tongue and groove of 100mm thickness. The combustion chamber is a double fire road with exhaust gas circulation structure, which consists of 28 vertical fire roads, the center distance between adjacent fire roads is 480 mm, and the thickness of the partition wall of the vertical fire road is 130 mm, in which there is a spanning hole on the upper part of the partition wall of the pairs, and the lower part eliminates the circulating holes of the side fire roads to prevent short circuit. The two ramps at the bottom of the vertical fire escape zone are set on both sides of the centerline of the combustion chamber, and the cross-sectional area of the side ramps is increased on the basis of JN43-58-II coke oven to ensure the gas supply to both ends of the furnace head.
3) heat storage room
The role of the heat storage room is to use the heat of the accumulated exhaust gas to preheat the combustion of air and poor gas.JN43-58-II coke ovens each charring chamber at the bottom of the two heat storage room, one for the gas heat storage room, the other for the air heat storage room. They are connected with two combustion chambers placed on their sides at the same time. The combustion chamber is directly below the main wall, the main wall has a vertical brick gas channel, coke oven gas from the basement gas and the main pipe through this channel into the bottom of the vertical fire road and air mixing combustion. Due to the airflow guidance on both sides of the main wall, there is a brick gas path in the middle, the pressure difference is large and easy to string leakage. Therefore, the brick gas channel system with an inner diameter of 50mm pipe brick, pipe brick with tongue groove outside the shaped brick staggered into the main wall thickness of 270mm. Heat storage room hole width of 321.5mm, put 17 layers of nine-hole thin-walled lattice brick. In order to make the longitudinal airflow in the heat storage chamber evenly distributed, diffusion grate bricks are used, configured with diffusion or contraction hole patterns of different aperture diameters, and the partition walls of the heat storage chamber are all masoned with silica bricks, and their inner surfaces are lined with clay bricks.
4) Ramp zone
The passageway connecting the heat storage chamber and the combustion chamber is the ramp zone, which is located between the top of the heat storage chamber and the bottom of the combustion chamber, and is used for introducing air and gas and distributing them to each vertical flame path, as well as removing the exhaust gases. Each of the vertical fireways of the combustion chamber is connected to its corresponding ramp, and when heated with coke oven gas, air is fed in and exhaust gases are expelled by the two ramps, while coke oven gas is fed in by the vertical brick gasway. When heated with lean gas, one ramp feeds in gas and the other ramp feeds in air, and both ramps export exhaust gases after the change of direction. Ramp mouth arrangement of regulating bricks, in determining the size of the ramp section, generally should make the ramp mouth resistance accounted for the total resistance of the rising gas flow ramp 2/3-3/4; in order to maintain the temperature of the furnace head, should be made to the furnace head ramp exit section than the central 50% -60%; ramp mouth tilt angle should not be less than 30, the ramp section of the gradual reduction of the angle of the general less than 7 and so on.
5) foundation platform
Foundation platform is located at the bottom of the furnace body, which supports the entire furnace body, furnace facilities and mechanical mass, and transfer it to the foundation.JN43-58-II coke oven foundation for the downward spraying type, and the bottom plate, the top plate and the pillars are composed of reinforced concrete casting and become. In order to mitigate the effect of temperature on the foundation, there are 4-6 layers of red bricks between the lower part of the coke oven masonry and the foundation platform.
6) Roof area
The roof area of JN43-58-II coke oven is built with coal loading holes, ascending pipe holes, fire watching holes, flooding holes, and drawbar hooks. The solid part of the roof is built by the waste refractory bricks in the process of laying the furnace, and the surface of the roof is built by the cylinder bricks which have good abrasion resistance and can resist the erosion of rainwater.
In short, the structure of JN43-58-II type coke oven is characterized as a compound-heat type coke oven with double fire ways with exhaust gas circulation, coke oven gas downward injection, and two compartments of heat-storage chamber, which has the advantages of tight structure, header not easy to be cracked, high direction of heating uniformity, high thermodynamic efficiency, fewer bricks, low volatility, and so on.
3, furnace protection machinery and equipment
The four main coke oven car: coal car, push coke car, stop coke car and coke quenching car. One of the coal loading car is on the roof of the coke oven from the coal tower to take coal and charging coal to the charging room of the coke oven machinery, push coke car role is to complete the opening and closing of the mechanical furnace door, push coke, flat coal and other operations, stop coke car role is to open and close the door of the coke side of the furnace door will be launched by the charring room of the furnace cake through the coke chute into the coke quenching car to complete the operation of coke quenching car is used to accept the launch of the charring room of the Hong call and sent to the coke tower to quench the coke through the spraying and will be quenched. Then the coke is unloaded onto the cool coke table.
The furnace protection equipment includes furnace columns, protection boards, vertical and horizontal tension bars, springs, furnace door frames, resistance walls, and machine side, coke side operating platforms, etc. The main function is to use adjustable springs to protect the furnace. The main role is to use the potential energy of the adjustable spring continuously to the masonry to exert sufficient, evenly distributed and reasonable protective pressure, so that the masonry in its own expansion and external forces can still maintain the integrity and tightness, and have sufficient strength to ensure the normal production of coke ovens.
Heating gas feeding equipment, large coke ovens are generally reheat type, available two kinds of gas heating, the role of the coke oven to transport and regulate the pressurized gas.
Deserted gas export equipment includes: rising pipe, bridge pipe, water seal valve, gas collection pipe, suction pipe, tar box and the corresponding spray ammonia system. Its role is: first, the out of the barren gas smoothly out of the furnace door near the knife edge of the gas pressure is too high to cause smoke and fire, but also to maintain and control the carbonization room in the whole coking process for the positive pressure; second, the out of the barren gas moderate cooling, not due to high temperature caused by the deformation of the equipment, resistance to high sound and air blower, condensing load increases, but also to maintain the tar and ammonia good fluidity.
4, coke quenching, screening coke process and equipment
Handan Steel coking plant uses wet coke quenching, its coke quenching system includes coke quenching tower, spraying devices, water pumps, powder coke settling tank and powder coke grabs hooks and so on. Coke quenching process is: coke quenching car into the coke quenching tower, the use of infrared receptors, receiving red coke itself out of the infrared and signal current, the current amplification triggered by the circuit to start the coke quenching pumps, and with the help of electronic timing devices to control the coke quenching time. About 20% of the water evaporates during coke quenching, and the un-evaporated water flows into the powder coke precipitation tank, and the clarified water flows into the clean water tank for recycling. After coke quenching, the coke is unloaded onto the cool coke table and parked for 30-40min to make its water evaporate and cool down, and the individual red coke which has not been quenched yet is quenched artificially with water.
Screening coke according to the size of the coke will be divided into 60-80mm, 40-60mm, 25-40mm, 10-25mm, <10mm and other levels, the main equipment has a roller screen and *** vibration screen. Generally, large coking plants are equipped with coke silos and screen coke buildings, coke larger than 40mm will be screened out by roller screen, and sent to the block coke silo through the belt conveyor. The coke under the roller screen is divided into other three levels by double vibrating screen, respectively, into the warehouse.
Seven, the recovery of coking chemical products
1, the initial cooling of gas and tar recovery
1) The main components of barren gas are net coke oven gas, water vapor, coal tar gas, benzene hydrocarbons, ammonia, naphthalene, hydrogen sulfide, other sulfide, hydrogen cyanide and other cyanide, pyridinium salts and so on.
The recycling production process consists of: the barren gas generated in the coke oven carbonization room is cooled, transported, and recycled in the chemical product recycling workshop to recover chemical products such as coal tar, ammonia, sulfur, benzene hydrocarbons and other chemical products, and at the same time, the gas is purified. The gas purification workshop consists of condensation blower section, HPF desulfurization section, ammonium sulfur section, final cooling and benzene washing section, crude benzene distillation section, etc. The gas flow is as follows: barren gas → primary cooler → electric tar trap → blower → pre-cooling tower → desulfurization tower → spray saturator → final cooling tower → benzene washing tower → net gas.
Recovering coking chemical products is of great significance. Coal in coking, in addition to about 75% into coke, there are about 25% to generate a variety of chemical products and gas. From the coke oven gas, after cooling and treatment with a variety of absorbents, can be extracted from coal tar, ammonia, naphthalene, hydrogen sulfide, hydrogen cyanide and crude benzene and other chemical products, and get a net coke oven gas, ammonia can be used to make ammonium sulfate and anhydrous ammonia; hydrogen contained in the gas can be used to make ammonia, synthetic methanol, hydrogen peroxide, cyclohexane, etc., synthetic ammonia can be made into further fertilizers such as urea, ammonium nitrate and ammonium bicarbonate; The contained ethylene can be used as the raw material for ethanol and trichloroethane, hydrogen sulfide is the raw material for the production of monoclinic sulfur and elemental sulfur, and hydrogen cyanide can be used for the production of sodium or potassium xanthohaematite; crude benzene and coal tar are very complex semi-finished products, which can be obtained after refining and processing: carbon disulfide, benzene, toluene, toluene, toluene, gumarone, phenol, cresol, and pyridinium salts and asphalt, etc., which have a wide range of uses and are Synthetic fibers, plastics, dyes, synthetic rubber, pharmaceuticals, pesticides, radiation-resistant materials, high-temperature-resistant materials, as well as important raw materials for the defense industry.
Desert gas from the coke oven 82 ℃, with tar and ammonia along the suction gas pipeline to the gas night separator, gas night separation of desert gas from the upper part out, into the cross-tube primary cooler in two sections of cooling. The upper section uses circulating water and the lower section uses low temperature water to cool the gas to 21-22℃. The gas discharged from the lower part of the cross-pipe primary cooler enters the electric tar catcher to remove the tar entrained in the gas, and then is pressed by the blower and sent to the desulfurization section.
Tar and ammonia separated from the gas night separator first enter the mechanized ammonia clarifier tank, where ammonia, tar and tar residue are separated. The upper part of the ammonia water flows into the circulating ammonia intermediate tank, and then the circulating ammonia pump is sent to the coke oven gas collector to spray cooling gas, and the remaining ammonia water is sent to the remaining ammonia tank. The tar in the lower part of the clarifying tank flows into the tar separator by hydrostatic pressure to further decompose the tar and tar residue by settling, and the tar is sent to the tar storage tank of the oil depot section by tar pump. The tar slag settled at the bottom of the mechanized ammonia clarification tank and tar separator is scraped to the tar slag truck, which is regularly sent to the coal yard and artificially blended into the coking coal.
The residual ammonia entering the residual ammonia tank is sent to the tar remover by the residual ammonia pump, and after removing the tar, it flows to the residual ammonia intermediate tank, and then is sent to the residual ammonia vaporizing device of the ammonium sulphur section by the residual ammonia intermediate pump, and the removed tar flows to the underground venting tank.
3) The structure and working principle of the main equipment
①Centrifugal blower
Centrifugal blower consists of guide impeller, shell and working impeller installed on the shaft. Gas inhaled by the blower to do high-speed rotation in the center of the rotor of the first working impeller, gas in the centrifugal force is thrown to the center of the annular gap in the shell that is generated by the decompression, gas is constantly being inhaled, leaving the impeller gas speed is very high, when entering the annular gap, part of the dynamic head of pressure into a static head of pressure, the movement of the gas speed is reduced and through the conduit to enter the second impeller, resulting in a reduction of speed with the first impeller, the same effect of the gas, and the first impeller. The static pressure head of the gas is raised again. The gas from the last impeller flows into the outlet connecting pipe from the annular gap of the shell and is fed into the pressurized pipeline.
The centrifugal blower used in coking plant is divided into 150m3/min, 300 m3/min, 750 m3/min, 1200m3/min and other specifications according to the size of the conveying capacity, and the total pressure head is 30-35kpa.
②Transverse pipe primary cooler
The main structure of the gas transverse pipe primary cooler in the coking system is including the primary cooler shell, the primary cooler tube, the primary cooler tube, the primary cooler tube, the primary cooler tube, the primary cooler tube, the primary cooler tube, the primary cooler tube, the primary cooler tube, the primary cooler tube, and so on. The main structure of coking system production gas cross-tube primary cooler is including primary cooler shell, cooling tube bundle. Cross-tube primary cooler shell is welded by the steel plate into an upright rectangular body, before and after the shell on both sides of the primary cooler tube plate, tube plate outside the head. On the side and center of the shell, there is a spray liquid receiver, the top of the gas inlet and the bottom of the gas outlet. In the operation of the cross-tube primary cooler, in addition to cooling the coke oven gas, condensate is sprayed at the top and middle of the cooler to absorb the naphthalene in the coke oven gas and to flush out the naphthalene deposited on the cooling tubes, thus effectively improving the heat transfer efficiency.
③Electro tar trap
The body of electro tar trap is made of cylinder rolled from steel plate and combined with header at the top of the machine and arch bottom at the bottom of the machine.
The electric field of electric tar catcher has positive electrode and negative electrode. The positive electrode is made of steel pipe, which is fixed on the upper and lower tube plate, which is welded to the barrel of the tar trap. Negative electrode of the electric field, installed in the insulated box hanging down from the rod suspended on the hanger, the boom hanger are made of stainless steel, the boom is installed on the resistance cap to stop the gas impact insulated box. Negative electrode made of stainless steel, corona pole plate suspended under the lead pendant to straighten the corona pole, the lower part of the corona pole made of stainless steel under the hanger to fix the position of the corona pole line were penetrated into the center of the electrode field precipitation tar starved positive pole steel tube.
2, desulfurization section (HPF desulfurization)
Gas → pre-cooler → desulfurization tower → liquid sealing tank → (desulfurization liquid) reaction tank → regeneration tower → foam tower → (clear night) reaction tank
After the blower, gas enters into the pre-cooling tower to make counter-current contact with circulating cooling water sprayed on the top of the tower and is cooled down to 30 ℃, and then the pre-cooled gas enters into the desulfurization tower to make counter-current contact with desulfurization liquid sprayed down on the top of the tower to absorb the desulfurization liquid. After pre-cooling, the gas enters the desulfurization tower and contacts with the desulfurization liquid sprayed down from the top of the tower in the countercurrent direction to absorb the hydrogen sulfide in the gas (meanwhile, the ammonia in the gas is absorbed to replenish the alkali in the desulfurization liquid). The desulfurized gas is sent to the ammonium sulfate section.
The desulfurization solution which has absorbed H2S and HCN flows to the reaction tank, and then is sent to the regeneration tower by the pump of desulfurization solution, and at the same time, compressed air is fed into the bottom of the regeneration tower, so as to oxidize and regenerate the solution in the tower. The regenerated solution flows back to the desulfurization tower from the top of the tower through the liquid level regulator for recycling.
The sulfur foam floating on the top of the regeneration tower flows into the foam tank using the liquid level difference, and the sulfur foam is sent to the sulfur melting kettle by the foam pump, and the sulfur is melted neatly with medium pressure, and flows into the reaction tank at night, and the sulfur is bagged for export.
In order to avoid the accumulation of desulfurization liquid salts affecting the effect of desulfurization, a small amount of waste liquid is discharged and sent to coal blending.
3, ammonium sulphur section (spray saturator production of ammonium sulphur)
From the desulphurization and sulphur recovery section of the gas sent by the preheater into the upper section of the spray ammonium sulphur spray saturator spray chamber, where the gas and the circulating mother liquor fully in contact with the ammonia therein is absorbed by the mother liquor, and then through the ammonium sulphur saturator in the deacidifier separation of the acid mist sent to the benzene elution section.
The mother liquor in the lower part of the saturator is continuously pumped out by the mother liquor circulation pump and sent to the upper section for spraying, absorbing ammonia in the gas and circulating and stirring the mother liquor to improve the crystallization process of ammonium sulfate. Ammonium sulfur in the mother liquor of the saturator is continuously crystallized, and the crystallization pump sends it together with a part of the mother liquor into the crystallization tank to settle, and then discharges it to the centrifuge for centrifugal separation, filters out the mother liquor, and obtains the crystallized ammonium sulfate. The mother liquor separated by centrifugation and the mother liquor overflowed from the crystallization tank flow back to the saturator together. The clean ammonium sulfate unloaded from the centrifuge is sent to the boiling dryer by a screw conveyor. The hot air needed for the boiling dryer is sent into the hot airer by the blower to be heated by steam and then boiled and dried, and the dried ammonium sulfur enters into the ammonium sulfur storage tank, and then is weighed and packed by the packing scale and sent to the ammonium sulfur warehouse.
4, final cooling and benzene washing section
The gas from the ammonium sulfate section enters the final cooling tower and cools the gas in two sections with circulating cooling water in reverse contact with the gas, and then the gas is cooled to a certain temperature and sent to the benzene washing tower. At the same time, in the upper section of the final cooling tower to add a certain amount of alkali, further removal of H2S in the gas, the condensate discharged from the lower section is sent to the cyanide wastewater treatment section, and the alkali condensate discharged from the upper section is sent to the top of the ammonium sulphur section of the ammonia evaporation tower.
The gas from the final cooling tower enters the benzene washing tower, where the crude benzene in the gas is removed by oil-poor scrubbing and then sent to the gas users. The lean oil sent from the crude benzene distillation section is sprayed from the top of the benzene washing tower, which is in reverse contact with the gas to absorb the benzene in the gas, and the rich oil at the bottom of the tower is sent to the crude benzene distillation section through the oil-rich pump to remove the benzene and then recycled for use.
5. Crude benzene distillation section
The rich oil sent from the final cold benzene washing device enters the oil-rich tank, and then is sent through the oil-vapor heat exchanger and the poor-rich oil heat exchanger with the oil-rich pump, and then is heated by the tubular furnace and enters into the de-benzene tower, where it is extracted and distilled with the direct steam from the regenerator. The crude benzene vapor escaping from the top of the tower enters the oil-water separator after passing through the oil-vapor heat exchanger and crude benzene condensation cooler. The separated crude benzene enters the crude benzene reflux tank, part of which is sent to the top of the tower as reflux liquid by the crude benzene reflux pump, and the rest enters the crude benzene intermediate tank, and then is pumped to the oil depot with the crude benzene product.
Coal washing plant process flow
Coal processing, gangue treatment, material and equipment transportation constitute the mine surface system. Among them, the ground coal processing system consists of the main links such as receiving coal, screening, crushing, selecting beauty, storage and loading. It is the main body of mine ground production.
Receiving coal is a certain capacity of coal bunker near the wellhead, accepting the coal lifted to the ground from the underground, to ensure the balanced and continuous production up and down the wellhead.
Screening
The operation of dividing a mixture of different particle sizes into various poles by means of a perforated screen is called sieving. The machine used for sieving is called sifter or sieve.
In coal preparation plants, screening is widely used in the preparation and handling of raw coal. According to the different methods of screening, they are categorized as dry screening and wet screening.
Crushing
The process of pulverizing large material into small particles is called crushing. The machine used for crushing is called a crusher. In the coal plant crushing operation has the following requirements:
1) to adapt to the requirements of the selected particles; selective machinery can handle the coal particles have a certain range of degrees, more than this range of large pieces of crushing to be washed.
2) Some coal fast is coal and gangue intermingled with gangue coal, in order to select the fine coal, need to be crushed into smaller particles, so that the coal and gangue coal separation
3) to meet the user's particles requirements, after the selection of the product or coal fast crushed to a certain size
Materials crushed by mechanical methods, there are crushing, splitting, fracturing, breaking, crushing, grinding, and several other main way.
Coal selection
is the use of different physical, physical-chemical properties with other substances, in the coal plant with mechanical methods to remove impurities mixed in the raw coal, it is divided into different quality, specifications of the product to adapt to the needs of different households.
According to the location of the coal plant and the coal mine off coal plant can be divided into: mine coal plant, group mine coal plant, the center of the coal plant and the user coal plant; most of the existing coal washing plant in China is a mine coal washing plant. Modern coal washing plant is a continuous mechanical process consisting of many operations.
Jigging Coal Separation
The process of coal separation in a vertically pulsating medium according to the difference in particle density. Jigging coal jigging medium is water or air, individual also use suspension. Selection of coal in the most hydraulic jigging.
Jigger is the use of jigging sorting principle will be selected according to the density of raw materials sorted into fine coal, coal and gangue coal and other products equipment.
Heavy media selection
In the density greater than 1g/cm of the medium, according to the size of the difference in the density of the particles for coal selection, called heavy media selection or heavy media selection. The heavy media used in coal beneficiation have two types of heavy liquid and re-election flotation. The main advantage of heavy-medium coal selection is that the sorting efficiency is high with other methods of coal selection; into the selection of a wide range of strength, sorting machine into the material particles of 1000-6mm, swirler for 80-0.15mm production control is easy to automate. The disadvantage of heavy media coal selection is the complexity of the production process, high production costs, fast wear and tear of equipment, maintenance.
Heavy-media coal selection is generally graded into the selection. Sorting lump coal is generally carried out under the action of gravity with heavy media sorting machine; sorting froth coal under the action of centrifugal force with heavy media swirler.
Storage
Storage bunker: A bunker with a certain capacity set up to regulate the imbalance between production, transportation, and sales, and to ensure the normal and balanced production of the mines and the transportation department, to accept the finished coal products and to ensure that they can be shipped out smoothly and enter the final loading stage.
Loading: including loading (ship), crane and measurement.