10 Key Energy-Saving Technologies for Various Coking Processes

3) Introduction to key functional refractory materials for coke ovens and their application technologies: including a series of techniques such as “surface composite ceramic forming technology, preparation technology of high thermal conductivity siliceous materials, and furnace thermal repair technology”. The application of surface-composite ceramic molding technology enables the enlargement of coke oven door structures, resulting in a smooth surface. It addresses the problems of structural instability and poor sealing that led to gas leakage and environmental pollution caused by the use of small bricks in the past. High-thermal-conductivity silicon bricks replace traditional silicon brick refractory materials, resulting in a significant improvement in thermal conductivity; they enhance the thermal conductivity of the silicon bricks used in carbonization chambers while retaining other excellent physicochemical properties. Application status: Relevant technologies are applied in various enterprises such as Baosteel and Ansteel. Taking a 4-blast-chamber, 50-hole coke oven of a certain steel plant as an example, the use of high-thermal-conductivity silica brick materials can increase thermal efficiency by 5%. 4) Introduction to the high-efficiency recovery technology for the waste heat from coke oven rise pipes: The existing coke oven rise pipes are replaced with rise pipe heat exchangers. Waste gas at around 800°C flows through these heat exchangers, transferring its heat to a forced-circulation heat transfer medium such as circulating water or heat transfer oil, thereby producing saturated steam, superheated steam, and high-temperature heat transfer oil that can be used by end-users, thus enabling the recovery of waste heat from the coke oven gas. Application status: The technology for recovering waste heat from coke oven risers has been applied in a number of large enterprises such as Baosteel, Shougang, Baotou Steel, and South Korea’s Hyundai Steel, on over a hundred coke ovens. Taking the production of low-pressure saturated steam in a coking plant of a certain steel company as an example, the steam output per ton of coke exceeds 80 kg, and the energy consumption per ton of coke is reduced by more than 7 kgce/t. There is still room for improvement in this technology.

5) Introduction to the technology for recovering low-temperature waste heat from raw coal gas via heat exchange in the upper section of the primary cooler: The conventional two-stage cross-tube type primary cooler is redesigned into a three-stage heat exchange system, consisting of an upper stage, a middle stage, and a lower stage. Hot water, circulating water, and low-temperature water are supplied to these stages respectively. The hot water comes from the refrigeration units or ventilation and heating systems; its temperature is 63–65°C. It is pumped to the upper section of the pre-cooler, where it absorbs heat from the raw coal gas, causing its temperature to rise to 73–75°C. Afterwards, it is sent back through pipelines to the refrigeration units or ventilation and heating systems, while the temperature of the raw coal gas drops from 81°C to 79–75°C. The waste gas is further cooled to about 21°C by the middle and lower sections of the primary cooler. This technology can be widely promoted and applied in most newly built coking enterprises. Application scenarios: It is used in enterprises such as Shanxi Liheng Coking, Tongling Taifu, and Xintai Chingda Coking. Taking an annual coke production of 1 million tons as an example, waste heat recovery results in 12,000 to 18,000 tons of low-pressure steam, thereby significantly reducing the amount of circulating water required. 6) Introduction to the waste heat recovery process technology for coke oven flue gas: The flue gas from the coke oven enters a waste heat boiler for heat exchange before being discharged into the chimney, where low-pressure steam is generated. Auxiliary equipment is placed below the boiler to save space; the induced draft fan operates at variable frequency based on the pressure in the main flue, while the feed water is automatically adjusted using a two-stage control system. The level of water in the steam drum remains stable, and its pressure is automatically regulated as well, ensuring stable steam pressure. Finned tubes combined with heat pipes are used in the heat exchangers to prevent corrosion at low temperatures. Application: Per ton of coke, 0.05–0.1 tons of 0.6MPa saturated steam can be produced, with an investment payback period of ≤2 years. Per ton of coke, this reduces CO2 by about 15.5 kg, SO2 by about 0.5 kg, NOX by about 0.24 kg, and dust by about 4.5 kg.

7) Introduction to the high-temperature ultra-high pressure/ultra-high temperature ultra-high pressure reheated boiler power generation technology for dry quenching of coke: An intermediate primary reheating system is incorporated into the waste heat recovery system for dry quenching of coke, utilizing the high-quality thermal energy of the high-temperature circulating gas entering the dry quenching boiler to improve the overall cycle thermal efficiency. The intermediate reheat system of this technology makes use of the new steam generated by the boiler; after this steam expands and does work in the high-pressure cylinder of the turbine, the high-pressure exhaust steam enters the reheater of the boiler, thereby increasing the superheating temperature of the reheated steam. The exit temperature of this reheated steam is comparable to that of the main steam, after which the high-temperature reheated steam is sent to the low-pressure cylinder of the turbine to continue expanding and doing work. The internal efficiency of turbines operating under high-temperature and ultra-high-pressure/high-temperature, ultra-high-pressure conditions with intermediate single reheat is high; their thermal systems also exhibit high thermal efficiency. The intermediate reheat technology not only increases the dryness fraction of the last-stage blades of the turbine but also ensures the stable operation of the unit. This technology enables full utilization of the waste heat from coke dry quenching, thereby enhancing the economic viability of waste heat power generation. Application: The overall power generation efficiency is improved by 0–13% compared to generators of the same scale operating under high temperature and high pressure conditions (9.8 Mpa, 540°C). Taking a project with a dry quenching capacity of 210 t/h at a certain plant as an example, the annual power generation time is 8,000 hours, resulting in an increase in annual power generation of over 33.6 million kW·h, and annual savings of approximately 413 tons of standard coal ； The annual power generation revenue increases by 16.8 million yuan (calculated at 0.5 yuan/kW·h). 8) Introduction to the waste heat recovery technology using ammonia water in coke ovens: The temperature of the ammonia water in coke ovens is 70–80°C, and both the circulation volume and the amount of waste heat available are substantial. A lithium bromide refrigeration unit is used, with water as the refrigerant and a lithium bromide aqueous solution as the absorbent; taking advantage of the low boiling point of water at high vacuum conditions, it recovers the heat from the circulating ammonia water to achieve cooling. Application status: The industry application rate is about 10%, reducing process energy consumption by 0.5~1 kgce/t of coke.

9) Introduction to energy-saving heat pump ammonia vaporization technology: A type II absorption heat pump unit is used in place of conventional ammonia vaporization condensers to recover the latent heat from the ammonia vapor at the top of the ammonia vaporization tower; after temperature enhancement, this heat is used to heat circulating hot water, which is then utilized to warm the wastewater at the bottom of the tower as a partial heat source for heating the ammonia vaporization tower, thereby reducing steam consumption. Compared with the conventional ammonia evaporation process, the heat pump ammonia evaporation process uses a tower top waste heat recovery system and an ammonia water reflux system composed of heat pump units, hot water reboilers, circulating hot water pumps, vapor-liquid separators, ammonia water reflux pumps, and expansion tanks, to replace the fractionator in the conventional ammonia evaporation process. Application: Compared with the conventional ammonia evaporation used in many current coking enterprises, this technology reduces low-pressure steam consumption by about 41% and circulating water usage by about 13%. 10) Introduction to the steam-based negative-pressure crude benzene distillation technology: This technology maintains a negative pressure inside the benzene removal tower through vacuum devices, thereby reducing the boiling points of various components in the solution. This approach helps to lower the distillation temperature and reduce heat consumption. By optimizing the operating parameters for crude benzene processing and improving the design of the tower trays, it is possible to effectively address the issue of high steam consumption in coking crude benzene processing, resulting in significant energy savings. Application: It can reduce low-pressure steam consumption by 50% and circulating water usage by 25% in the rectified crude benzene distillation process, thereby cutting operating costs by 16%.

[HaiChuan Safety Discussion] Compilation of potential hazards around us – illustrated with pictures and texts. Everyone is welcome to join the discussion. https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5705518 (Source: HaiChuan Chemical Forum (Huahai Chuanliu hcbbs))

【HaiChuan Safety Discussion】Hidden Dangers Around Us – Storage tank lightning protection grounding wires that remain submerged in water for long periods and are covered in moss https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5716826 (Source: HaiChuan Chemical Forum (HuaHaiChuanLiu hcbbs))

【HaiChuan Safety Discussion】Hidden Dangers Around Us – Flange bolts used in natural gas systems not selected appropriately https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5716839 (Source: HaiChuan Chemical Forum (HuaHaiChuanLiu hcbbs))

【3D Process Flow】Summary Post--Petroleum Refining Process Flow Diagram 08--Typical Processes for Crude Oil Desalination and Dewatering https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5716875 (Source: Haichuan Chemical Industry Forum (Hua Haichuan Liu hcbbs))