Imidazole ionic liquid effects on coal swelling behavior and pyrolysis characteristics: Experiment and molecular simulation

In view of low-rank coal conventional swelling solvent large pollution and the clean efficient utilization of coal, the effects of imidazole ionic liquid (IL) pretreatment with different anion groups as green solvent on coal thermal expansion and pyrolysis performance were investigated. IL interacts with coal molecules, destroying the hydrogen bonds, resulting coal expansion. Different anion groups have different modification effects, [Bmim]Cl has the best swelling effect, which is 17.37 % higher than raw coal, and the best modification time is 24 h. In addition, IL modification has a catalytic effect on coal pyrolysis, which can significantly reduce the maximum weight loss temperature and increase tar content. Coal solvent pretreatment provides a good theoretical basis for application of swelling and pyrolysis. The reduction of thermochemical reaction temperature not only reduces the content of heavy groups in pyrolysis products, but also provides new ideas for carbon emission reduction.