Abstract: Based on the original operation scheme of tank containing solid and heavy dirty oil, which is used to match the device of coal liquefaction and in the light of the problems in medium pressure steam heating, bi-layer-impeller agitator, pump filter blocked by deposition, bearing sleeve shedding and heating coil fracture, the cause of coal gum formed at tank bottom is analyzed.Resultsshow that the coal gum is coming from the low coalification degree of the selected coal, static pressure of the storage medium, high temperature, micron powder, centrifugal force of agitator impeller and so on, which constitute the conditions of coal crystal nucleus enlargement. With the increase of gum area, the coal crystal nucleus grows up continuously, and the agglomerate rate and rigidity of materiel are increased. As a result, the stirring of the agitator is failed. The optimization methods are offered that uses low pressure steam as heat medium of underlayer heating coil, setting differential pressure systems in the pump filter, adding one more layer impeller in agitator, adding hinge backstop and airtight flexible shaft at tank bottom, making trestle, coil heater and tank bottom more stable by using triangle structure. Therefore, the running efficiency of tank containing solid and heavy dirty oil is increased and the direct device of coal liquefaction and transportation system can run normally.