Lxperimental Study On Particle Removal Enhancement For Fine Particles In High Temperature Electrostatic Field

China was the largest consumer of energy in the world and the energy structure was still dominated by coal in a short period of time.The coal-fired power generation was the most important way of energy consumption in the downstream of coal industry.Coal grading and utilization of conversion technology was an important way to improve the level of clean coal utilization.It is necessary to particle collection in high-temperature flue gas before the SCR system.High-temperature coal pyrolysis gas in the coal utilization system carries a large amount of particulate matter,which can cause the tar quality to deteriorate when mixed with the condensed tar.It will reduce the energy conversion rate of the system and cause adverse effects such as abrasion or blockage of the pipeline and the equipment.Therefore,it is the high time that high-temperature flue gas purification should be utilized.Due to its advantages of high efficiency in dust removal,large amount of flue gas,low system energy consumption and good operation stability,electrostatic precipitator technology is the preferred method for removal of high-temperature flue gas particulate matter in the coal utilization system.However,electrostatic precipitator(ESP)generally operates in flue gas temperature below 300 ? conditions.At the same time,coal pyrolysis process produces a large number of carbon particles with low resistivity,fine particle size,prone to re-entrainment,which leads to reduce particle removal efficiency of the ESP.How to realize the efficient removal of the particles under the synergistic action of multiple fields in the high temperature range through static electricity is an urgent need to carry out a systematic study.This paper focused on the electrostatic precipitator technology and mainly studied the balance between electrostatic precipitation and re-entrainment mechanism.The dynamic removal characteristics and equilibrium state of particles under multiple electric fields conditions were analyzed to obtain the key factors affecting the equilibrium state.And the method of electrode optimization-temperature control to enhance particle removal for multiple parameters was proposed in order to achieve the purpose of strengthening electrostatic capture of high-carbon particles and inhibiting re-entrainment at high temperature.First,the variation of particle concentration in multi-electric field with residence time was studied to obtain the dynamic removal characteristics of particles.According to the analysis of the interaction between particles and collecting plates and the declining degree of particle emission concentration in short residence time under different conditions,the temperature,discharge parameters(voltage,etc.),flue gas parameters(flow velocity,etc.)were the key factors in the balance between electrostatic precipitation and re-entrainment.When other parameters were certain,the appropriate temperature or flow velocity drop or voltage increase will reduce the ultimate emission concentration of particles in the equilibrium state,which strengthens the electrostatic precipitation and reduces re-entrainment.Secondly,the research on multi-field parameters strengthening the electrostatic removal of particulate matter was carried out.The variation of particle dynamic and equilibrium state removal characteristics under different electrode structures and temperatures were compared and analyzed.The ultimate emission concentration of the prickle-shaped electrode at 500 K could be reduced to 3.24 mg/m3,which was better than other temperature.The method of temperature control and electrode optimization was formed to enhance particle removal.At the same time,according to the ultimate emission concentration and the ultimate removal efficiency of the particles with different size,the high limit of electrostatic precipitator could be assessed.Finally,the electrostatic removal of high-carbon particles from coal pyrolysis was studied.Inert gas was chosen as the recycle atmosphere,and it was found that a large amount of residual 0.1-1 ?m particles remained in the flue gas at equilibrium under stable operation over a wide temperature range.At high temperature,through the electrode optimization method to strengthen the removal of high-carbon particles,95.0%of the collection efficiency was achieved at 700 K.In this way,the re-entrainment was effectively controlled to ensure that the operation of electrostatic precipitator was stable.