Date of Publication:2018-01-01

Journal:化工进展

Volume:37

Issue:5

Page Number:1985-1991

ISSN No.:1000-6613

Abstract:CO2liquefaction is a crucial procedure for carbon capture,utilization and storage(CCUS). The conventional cryogenic technique,running with the temperature lower than –20℃ and to prevent water from freezing,requires a complicated dehydration unit and consumes numerous mechanical power for refrigeration,and consequently the total running cost for CCUS is increased greatly. In this instance,a novel liquefaction technique based on LiBr absorption refrigeration system using flue gas waste heat was proposed in this research. The LiBr absorption refrigeration system driven by flue gas waste heat was used for generating the cold source at about 4℃. At the same time,the liquefaction temperature is increased to about 7℃ via upgrading the pressure of crude CO2,so that it can be well matched with the refrigeration condition. Moreover,the increase in liquefaction temperature can avoid the holdback relating to water freezing and CO2hydration,and it is beneficial that the complicated dehydration unit is no longer demanded. Afterwards,process simulation and optimization was carried with ASPEN Plus. The simulation results revealed that the novel liquefaction technique can reduce the ecific power consumption to 123.7kW·h/tCO2,and the energy saving degree is about 23.9% compared to the conventional technique. For a 200kt/a liquefaction plant,it is expected that this new-type technique can save electricity 7.70×106kW·h and running cost 2.25 million CNY per year. On the whole,the novel liquefaction technique behaves excellent in energy saving and economic benefit.

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