Experimental Research On Gas Desorption Of Coal In Electrostatic Field

The oil recovery is enhanced by the using of the applied electric field in the field of oil exploitation to increase the relative permeability of the oil phase,it is determined by the nature of electrochemical.This technology has the characteristicsof non mechanical,strong applicability,clean pollution free and low cost.Experimental study of static electric field to promote coal gas diffusion and desorption characteristics,The explore a new technique to strengthen the auxiliary gas drainage and provide theoretical support,For gas assisted technology to increase permeability diversification,gas efficient extraction and CBM development has important significance.Through experimental research and theoretical analysis,the influence of electrostatic field on gas emission and desorption characteristics of coal samples with different metamorphic degrees is experimentally studied,and the rule of gas release and desorption under different electrostatic fields was obtained,The research shows that:?1?Most of the coal decreases at the initial velocity at 4kv.high rank anthracite Guhannshan initial does not change significantly for speed of diffusion,but,the addition of 4kv to the uncharged P₁(?p_0¹5)and P₂(?p_45⁶0)increased.in eight the Pingdingshan metamorphic ore rich coal?lean coal in Hebi Minmetals voltage performance,It increased in 4KV,the range of 12²4KV is decreased,Iinitial emission velocity increased with the increase of voltage for low rank Yima lignite,achieve the maximum at about 12KV.The gas initial velocity and voltage relationship is the parabola form,It is known that the relationship between the initial velocity and the voltage of gas discharge is in a parabolic form,and there is the maximum value.?2?There are characteristic voltage and characteristic time of different metamorphic coal samples in electrostatic field.Analysis experiments found that the addition of electric voltage and power on time is the parabola form in effect of the desorption,there is a maximum,Characteristics of the voltage at 4kv¹2kv and the characteristic time is4h¹2h for four kinds of coal;voltage is dominant,energizing time and voltage when power on time and are inseparable.Voltage coupling can change the internal capacity,so that coal desorption change?increase or decrease?.?3?The electrostatic field can improve the initial desorption rate of coal gas.On the change of desorption speed?0⁵min?,The speed of desorption is faster before 3min.The desorption speed of 3⁴min is close to that of no power and tends to be stable after 5min or longer.It indicates that the electrostatic field promotes the rate of gas desorption.?4?The electrostatic field changes the coal ratio surface.With the increase of electrostatic field intensity,the change of free surface energy?decrease?increases.When the voltagereaches a certain level,the amount of change decreases,showing a trend of first increase and then decrease.Diffusion coefficient presented first increases then decreases,there is a maximum value,the maximum voltage is advantage and characteristics of corresponding charging time;Before 120s diffusion coefficient decreases significantly,leveling off after 120s,early explanation electrostatic field to speed up the gas diffusion;In the coal-gas system in electrostatic field,with the change of voltage increases and the electric time,oxygen containing functional groups modified,Influencing of coal and gas,thus changing the amount of gas desorption;with the increase of the degree of metamorphism,Effect of voltage range also increases,the reason that the influence of the coal and rock components of the high metamorphic coal,?the coupling relationship between the level of voltage and power on the length of time?.