Abstract:
The coupling of green hydrogen with coal chemical industry is an effective pathway to achieve the integrated development of new energy and traditional energy. In combination with the requirements of hydrogen purity, pressure, and volatility during the hydrogen utilization process in the coal chemical industry, the pathway and key technologies of coupling green hydrogen with the coal chemical industry are analyzed, and the suggestion that green hydrogen should be preferentially coupled with coal chemical processes that require pure hydrogen, such as coal-to-ammonia synthesis, coal-to-ethylene glycol, and direct coal liquefaction, is proposed. Taking an ammonia synthesis plant with an annual output of 300 000 tons as an example, the system scheme of coupling green hydrogen with coal-to-ammonia synthesis is analyzed. When the coupling ratio of green hydrogen is 26.3%, the optimal utilization of system materials can be achieved. At this time, the stable hydrogen supply from coal-based hydrogen production is 52 920 Nm
3/h, meeting the operation of the ammonia synthesis unit at 70% of its load. The hydrogen production capacity of the water electrolysis hydrogen production unit at full load is 60 000 Nm
3/h, the average annual hydrogen production is 18 750 Nm
3/h, the hydrogen storage capacity is 262 848 Nm
3, and the volatility of green hydrogen supply can meet the requirement of the load adjustment rate of the ammonia synthesis unit, which is 10%/h. The i MPacts of hydrogen production and hydrogen storage pressure, hydrogen storage capacity, etc. on the coupling system are studied. Higher hydrogen production and hydrogen storage pressure can significantly reduce the volume of the hydrogen storage system and the compression energy consumption. For example, when the hydrogen production and hydrogen storage pressure is increased from 1.6 MPa to 4.0 MPa, the volume of the hydrogen storage system can be reduced by about 75%, and the average hydrogen compression ratio can be reduced by about 37%. The cost and volatility of green hydrogen are the main bottlenecks restricting the coupling application of green hydrogen with the coal chemical industry at present. In the future, it is necessary to focus on breaking through key technologies such as efficient and flexible off-grid water electrolysis hydrogen production, medium-high pressure and large-capacity hydrogen storage, accurate prediction of green hydrogen production, and integrated regulation and control.
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