The analysis of the pulverized coal deposition in the pump cylinder in drainage and mining of the coal bed methane(CBM)

摘要

In drainage and mining of the coal bed methane(CBM), pump valve jams caused by the settlement of pulverized coal particles directly affect the normal production of the coal bed methane(CBM). From the study of the pulverized coal particle size, this paper summarizes the law of the pulverized coal particle size change in various stages of the coal bed methane(CBM) production well drainage and ming. By analyzing the pulverized coal particle velocity distribution along the pump cylinder, the viewpoint that the pulverized coal particle has a higher axial velocity in the central part of the settlement and has a lower velocity near the wall surface is put forward to. Based on the theory, the motion track equation of the pulverized coal particle can be got by calculation. Under the condition of considering buoyancy, fluid resistance and pressure drag, instant drop speed of the pulverized coal in water is calculated.