The inline hydrotreatment process was introduced to improve the quality of recycle solvent and product oil. The activity of the hydrotreatment catalyst (Ni-Mo-P/Al_2O_3) for the coal liquefied crude oil with coexistent gasses such as CO, H_2S, NH_3 and H_2O was investigated by using small scale fixed bed reactors. The deactivation of hydrotreatment catalyst was not observed conspicuous during 1600 hours, and it was concluded that this catalyst could maintain its activity for a long time under practical conditions in coal liquefaction process.
