Jinling Branch Coal Chemicals Purification Unit Hydrogen Production from Water-Coal Slurry: Purification Technology Upgrade Project

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Recently, the technical renovation project for the coal chemical purification unit at the Jinling branch of Sinopec Corporation was officially launched. This project will optimize the purification process for hydrogen production using water-coal slurry, reduce the costs associated with hydrogen production, and effectively improve the unit’s energy efficiency and economic performance. The industry to which this project belongs is coal-based syngas production. The project investment amounts to 296.65 million yuan, of which 15 million yuan is allocated to environmental protection measures, accounting for 5.06% of the total investment. The project covers an area of over 15,000 square meters and mainly includes tasks such as optimizing the desulfurization/carbon removal processes, upgrading the chillers and related systems, and improving the flare system. In recent years, as the company has continued to improve the quality of its oil products, the hydrogen supply demand from the coal-based hydrogen production units has increased accordingly. The existing process suffers from issues such as low quality of the crude hydrogen, low concentrations of acidic gases in the output, and high energy consumption in the ammonia absorption refrigeration equipment. This technical upgrade project aims to replace the existing desulfurization/carbon removal processes with acid gas removal processes, and the ammonia absorption refrigeration process with propylene compression refrigeration processes. Once the project is completed and put into operation, it will effectively increase the production capacity of the facility, reduce the costs associated with hydrogen production from coal, and contribute to the high-quality development of the company. At present, after successfully completing tasks such as the demolition of equipment in the old factory building and the relocation of underground pipelines in the preliminary phase, the project team is advancing pile foundation work in an orderly manner; the project is expected to be completed by the end of next year. Project Overview: This project is a renovation of purification facilities, involving the replacement of the existing NHD desulfurization and decarbonization processes with the low-temperature methanol washing process, which features lower energy consumption and superior operational parameters. The modified low-temperature methanol wash process: improves the quality of the crude hydrogen product by removing CO2 to levels below 20 ppm and H2S to levels below 0.1 ppm, thereby reducing hydrogen loss during the subsequent methanation process ； To further reduce the energy consumption of the purification units, the energy consumption of the low-temperature methanol washing unit can be reduced by 159.283 GJ compared to the NHD process ； Reduce the hydrogen sulfide concentration in process exhaust gases; the normal level of hydrogen sulfide in such gases should be below 3 ppmv, thereby further minimizing the impact on the surrounding environment. By switching to the low-temperature methanol washing process for the purification unit, the production cost per ton of hydrogen can be reduced by 145 yuan (equivalent to 0.013 yuan/Nm3). The construction of this project meets the requirements of clean production.