Abstract: Addressing the constraints of high energy consumption, high carbon emissions, and high costs in hydrogen production through water electrolysis within the coal chemical industry chain, a study was conducted on the coupling design of hydrogen production through water electrolysis and the coal chemical industry chain. Through the coupling design of the hydrogen production system, thermal energy system, and oxygen system, not only were significant achievements made in carbon emission reduction, but also the production costs of the industry chain were reduced. This is of great significance for innovating new energy consumption models and promoting the green and low-carbon transformation of energy. The research shows that, taking the coal chemical industry chain producing 3.0×10⁵ m³/h of hydrogen, 700 kt/a of methanol, 350 kt/a of acetic acid, and 1.0×10⁵ m³/h of methane gas as an example, by adopting the coupling process of hydrogen production without conversion, the demand for purified gas in the coal chemical industry chain is reduced from 9.4×10⁵ m³/h to 2.4×10⁵ m³/h. The conversion unit and PSA unit are eliminated, and the scale of the air separation unit, gasification unit, and rectisol unit is reduced by 80%. Investment in process equipment increased by 5.6%, coal consumption for gasification is reduced by 4 080 kt/a, and CO₂ emissions are reduced by 9 147.20 kt/a. Equipped with a 6.5×10⁵ m³/h hydrogen production device through water electrolysis, it can consume 3.25 GW.h of green electricity per hour, the CO₂ emissions have been reduced by 102.44%, achieving "net zero" CO₂ emissions in the coal chemical industry chain. After coupling with the thermal energy system,the output of driving steam increases by 130 t/h, and the yield rate is improved by 36.5%. When the price of green electricity is 0.2 yuan/(kW.h), after the by-product oxygen from hydrogen production through water electrolysis is utilized in a graded manner, the cost of hydrogen production can be reduced to 1.01 yuan/m³, which is comparable to the cost of gray hydrogen.

Key words: hydrogen production through water electrolysis, coal chemical industry, coupling process, thermal energy, oxygen, carbon emission reduction