Property and its mechanism of enhanced gas desorption from anthracite under electrochemical treatment

An experimental device of intensifying gas desorption from coal and rock by electrochemical method has been independently developed.It is composed of gas injection system, degassing system, temperature measurement and control system, data acquisition system, and electrochemical treatment system.The innovations of the device are as follows: the adsorption-desorption vessel with acid-alkali corrosion and good insulation property, including electrolyte chamber and electrode-located rings, is designed to ensure the infliction of electrochemical field; and by setting the air outlet and liquid inlet in each end cap of vessel, so that the process of motion-oriented of electrolyte and gas in pores and fractures of anthracite under electrochemical treatment can be researched. The device can be used to establish a new theory of electro-hydrodynamic of coal and rock.Experiments on intensifying gas desorption from anthracite in different electrolytes were conducted using this device.The results are as follows: the desorption ratio of gas in the side of anode is higher than in the side of cathode when the electrolyte is acid, however, the situation changes when the elec-trolyte is neutral or alkaline; the ultimate desorption ratio of gas increase (from 61.84% to 87.26%) with increasing p H and the average desorption rate increases by 5.59 times, since the electrochemical treatment improves the diffusion coefficient of anthracite through the following three functions: the adsorbed gas can be separated from coal surface and driven in the action of electro-osmosis, which provides impetus for gas migration; the pores and fractures increase with the treatment of electrolytic dissolution of minerals and electrophoresis migration of charged particles such as coal powder and clay, which shorten gas diffusion distance; the temperature of anthracite increases, which enhance the activity of gas molecules.