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This post was last edited by wangshaobo on 2025-6-15 15:04. Measures to Improve the Quality of Coke and Chemical Products: This plan has been formulated to ensure that the products meet the specified quality standards, satisfy customer needs, and help gain a larger market share for these products. I. Coke control plan: Quality control of coke begins with controlling the raw coal and its proportions. (1) Measures for isolating individual coal types in the coal yard: 1. Ensure proper management of individual coal types in the coal yard, so as to prevent mixing of different coal types ； Properly prepare the coal mixture and carry out crushing. To ensure the accuracy of coal blending and maintain coke quality, the following measures have been established: Each type of coal stored must have a sign indicating its name ； A distance of 2 meters must be maintained between coal piles of different coal types ； The factory management assigns dedicated section leaders in the workshops to be responsible for stacking coal and mixing it; the team leaders assist them, while the workshop director oversees the overall work ； The factory management and the production department conduct regular inspections; any non-compliant issues are promptly corrected, and reports are submitted for appropriate sanctions to be imposed. (II) Process control management of coke quality: strict attention should be paid to the technical parameters related to fire adjustment and gas composition; a reasonable heating regime is key to improving coke quality. Ensure uniform maturation of the coke to guarantee that its volatile matter content is within acceptable limits. Under a reasonable heating regime, ensuring that the five key coefficients are within acceptable ranges is necessary to maintain stable coke quality. The following steps must be taken: 1. Ash content control. 1.1 Ensure that, with the quality parameters of the coal to be fed into the furnace meeting the required standards, no waste materials get mixed into the coal at the coking coal storage area or during the process of feeding coal into the coke oven. 1.2 It is necessary to ensure that the pressure in the coke oven gas collection pipes remains within specified limits; negative pressure in the carbonization chambers must be avoided, as this can lead to the absorption of external air, causing combustion of chemical products, an increase in nitrogen and carbon dioxide levels, and a reduction in the calorific value of the gas. Additionally, the combustion of coke results in an increase in ash content. Therefore, the staff responsible for operating the rising pipes adjust the pressure in these pipes, while the computer system monitoring the gas mixture keeps track of the pressure and temperature, and promptly communicates this information to the staff working on the rising pipes. 2. Volatile matter control 2.1 According to the standard temperature for coke ovens, regularly adjust the straight-line temperature and cross-row temperature throughout the oven, ensuring that K remains within the range of ±20°C, with uniformity maintained in both the vertical and horizontal directions regarding the cross-row temperature. 2.2 If equipment failures affect coke pushing and it is necessary to extend the coking time, the addition and subtraction cocks should be adjusted accordingly based on the duration of the impact, in order to reduce the amount of gas supplied and maintain the temperature within the specified range. 2.3 Ensure that the temperature of the burner head is maintained within ±70°C of the standard temperature, and must not be lower than 1100°C; furthermore, its difference from the average temperature of the entire furnace shall not exceed ±50°C. 2.4 The four coefficients for coke ovens—K horizontal, K uniformity, K head, and K stability—must all be greater than 0.95. Gas team personnel constantly monitor the set gas pressure and flow rate; any deviations in flue suction are promptly corrected to ensure they remain within the specified range. 2.5 According to the coke pushing plan, the moisture content of the coal used in firing is analyzed to determine the amount of gas required, as well as any changes in the flue draft; this ensures that the average temperature throughout the furnace remains within the specified range and that the K safety factor operates at the required level. 2.6 Arrange the coke pushing plan strictly in accordance with the specified coking time, and use the K3 coefficient for coke pushing control ； Increase efforts in equipment maintenance to ensure the proper operation of the four types of equipment. Any issues detected should be reported to the mechanical and electrical technicians promptly, so as to prevent equipment failures that could lead to shutdowns, affect the K3 coefficient, make it difficult to control various temperature parameters, and ultimately impact the quality of coke. 3. Moisture control 3.1 The third shift adjusts the quenching time based on the moisture content of the coke, and maintains timely contact with the chemical production workshop to ensure that the normal water level is maintained in the quenching tank. Water supply (water cut-off): 3.2 The sediment in the quenching tank is cleaned once a month, and coke powder is removed on a daily basis to ensure an adequate water supply to the quenching pump. 3.3 After extinguishing the coke, the coke quenching vehicle must be moved away from the coke quenching tower to control the water flow for 30 seconds, before the coke is poured onto the cooling bed for cooling. 3.4 The coking drying platform strictly follows a cyclic coke placement sequence to ensure that the coke can evaporate freely on the platform for over 20 minutes. 4. Control of coke transportation outside the plant 4.1 Quantitative screening shall be carried out based on the conditions of each shift; the coke and coke pellets must meet the required standards to ensure an adequate supply for each shift. The vibrating screen must be operated by two people at night, and any occurrence of mixed coke is strictly prohibited. 4.2 To ensure sufficient time for the moisture in the coke to evaporate, it is strictly prohibited to load coke that is still emitting steam or has just been taken out of the furnace. 4.3 The workers responsible for screening and removing coke, as well as those who work on the conveyor belts in the passageways, must conduct thorough inspections of the belt systems used for transporting coke. If red coke or smoking coke is detected on the belts, the operation of the belts must be stopped immediately so that such coke can be removed. 4.4 When stacking coke using a belt conveyor, a dedicated person shall be assigned to supervise the process; smoking or the stacking of red coke is strictly prohibited to prevent coke tempering. 4.5 Prevent the forklift from crushing coke; it is strictly prohibited to place loads on the forklift’s tires. 4.6 During loading, a dedicated supervisor must be present, and it is strictly prohibited to introduce coke dust into the coke. 4.7 Non-conforming products must be stored separately; before being transported, they must be homogenized and tested in the laboratory to ensure they meet the specifications before being loaded onto vehicles. Chemical products (I) Tar: 1. The tar and ammonia water are separated using a gas-liquid separator, and then they enter a mechanical clarifier for further separation. This mechanical clarifier is divided into three sections: the upper section contains ammonia water, the middle section contains tar, and the lower section contains tar residues. 2. For continuous production in three shifts, when using mechanized methods to clarify accumulated oil, it is necessary to press the oil two hours before the end of each shift, in order to ensure that the water content is separated from the tar within the tank. 3. In the tar product storage tank, steam is used to heat the tar to a temperature of 80–90°C, after which it is left to stand for 36 hours. Dehydrate again using the built-in dehydration holes of the tar tank to reduce the moisture content in the tar to less than 4%. (II) Crude benzene 1. Benzene washing: Control the temperature of the gas after the final cooling tower (26–28°C) as well as the temperature of the lean oil entering the benzene washing tower (around 30°C), to ensure that the absorption temperature is around 30°C, thereby enabling maximum absorption of benzene from the gas. It also keeps the gas temperature 1-2°C below the lean oil temperature, preventing the condensed water in the gas from entering the washing oil and affecting subsequent processes. 2. Benzene removal: Strictly control the temperature at the top of the benzene removal tower (92–98°C). When the distillation yield, as indicated by test results, is low (below 91%), reduce the temperature at the top of the tower accordingly (i.e., increase the flow rate of crude benzene) in order to raise the distillation yield. When the distillate volume is too high, increase the tower top temperature appropriately (i.e., reduce the recycle rate of crude benzene) to lower the distillate volume, while ensuring that it remains ≥91. At the same time, keep the oil-rich stream temperature at 170–180°C to achieve a high degree of benzene removal and save steam. The direct steam opening should not be too large, otherwise it will lead to a decline in the quality of crude benzene, resulting in products that do not meet the standards. 3. Countermeasures: When the quality of crude benzene fails to meet the standards (i.e., <91), take samples of rich and poor oil to test for moisture content. If the moisture level is too high (>1), check the equipment (cooling water) to determine whether water has entered the oil washing process. If the moisture level is within the acceptable range, reduce the temperature at the top of the tower slightly to increase the flow rate of crude benzene back into the system; at the same time, reduce the amount of direct steam used in order to increase the distillation output and ensure that the product quality meets the requirements. Conduct tests once per shift, and test the crude benzene storage tank every 5 days to ensure proper quality control. (III) Ammonium sulfate: 1. Strictly control the acidity of the mother liquor; it should be between 4 and 6. If the acidity is too low, it can cause the product color to turn gray, while if it is too high, it results in smaller crystals of ammonium sulfate, leading to its dissolution in the acid. This affects the yield during discharge. To facilitate cyclic crystallization within the containers, more acid is added after the discharge is completed on the same day. This helps with cleaning the pipes and containers, as well as ensuring that the mother liquor is properly prepared for discharge the next day. When adding more acid, the acidity should be maintained between 14 and 16. It is also important to control the amount of water added so that the specific gravity of the mother liquor does not decrease; the specific gravity should remain above 1.26. 2. The temperature of the mother liquor must be strictly controlled. If the temperature is too low, the ammonium sulfide particles crystallize too smallly, resulting in a reduced growth rate and slower reaction rates; if the temperature is too high, ammonium sulfide dissolves, and the particles formed during discharge are small, leading to low yields and affecting the quality of ammonium sulfide. Therefore, the temperature of the mother liquor should be maintained between 50–55°C. 3. Strictly control the preheater temperature at 60–70°C; it must not fluctuate, as this could affect the temperature of the mother liquor. Regular adjustments and monitoring are necessary. (Water temperature: 60–90°C; water pressure: 1–2 kg) 4. When discharging material from the centrifuge, promptly adjust the water temperature and pressure to ensure that the free acid content in the ammonium sulfate product meets the standards. These parameters must be adjusted in a timely manner and strictly controlled. The drying operator must maintain a steady feed rate; the drying chamber must ensure that the moisture content of the dried ammonium sulfate does not exceed 0.5%, and the temperature should reach 140°C. To keep the free acid level at no more than 0.08.