| In order to solve the problems of serious coal combustion pollution and low thermal energy utilization,coal gasification technology has realized the clean and efficient use of coal.However,the crude gas produced by the gasifier contains impurities such as dust,which will cause damage to subsequent process equipment,so dust removal and purification treatment is required for gasifier gas.The traditional wet dust removal process has serious heat loss and wastes water resources.The dry filtration dust removal technology has unsatisfactory purification effect and poor reliability.The electrostatic precipitator technology has the advantages of high purification efficiency,small resistance loss and stable operation.If it is applied to the crude gas purification system of the gasifier,it has a very good application prospect.Due to the high H2 content in the gasifier gas,the average particle size of the dust is small,and the specific resistance is small,it is easy to cause the instability of corona discharge and secondary dust.The purification of the electrostatic precipitator needs to solve the above technical bottlenecks,so it is necessary to grasp the electrical performance and influence rules of the gasifier dust in the electrostatic precipitator.The electrical performances of dust mainly include:corona discharge and charging performance,electrical conductivity,coagulation performance,adhesion and sedimentation law on the dust collecting plate,etc.Studying the electrical performance of gasifier dust in the electrostatic precipitator will provide a theoretcal basis for its industrial application.This article first analyzes the physical and chemical properties of gasifier gas dust,then studies the corona discharge characteristics of gasifier gas in the electrostatic precipitator,and then the effects of chemical and charging methods on the dust coagulation performance of gasifier are analyzed through experiments.After the experiment,the adhesion of the gas dust are measured,and the sedimentation law of the dust particles on the dust collecting plate is explored.Finally,the electric dust removal experiment is performed to find out the operating conditions when the dust removal efficiency is optimal.The experimental results show:?1?The dust of the gasifier is loose and porous,with a median diameter of 23.25?m,a specific surface of about 7.8 m2/g,and the specific resistance of the dust ranges from 104to 106?·cm.?2?The corona discharge order of each component in the gas is:H2>N2>CH4>CO>CO2,and as the gas pressure increases,the corona discharge voltage increases and the secondary current decreases,which affects the corona discharge characteristics.?3?The water mist charging,electric field characteristics and chemical coagulants all affect the coalescence of dust from gasifier.With the solid 1/4 nozzle,when the water pressure is 0.5 MPa,the voltage is 40 KV,and the cathode is the fish bone line,the condensation effect is the best;the coagulation effect is enhanced after the coagulant is added,and when XTG concentration is 1.0×10-22 g/L,LS-30 concentration is 0.5×10-22 g/L,the coagulation effect is the best.?4?The moisture content of the dust from gasifier is 2.28%,and its adhesion is 31.62 mg/cm2.With the increase of the moisture content,the adhesion also gradually increases;after adding the coagulant alone,the increasing effect of its adhesion is not obvious,and under the combined action of coagulant and water,the increasing effect of its adhesion is the best,which is 45.92 mg/cm2.?5?When the water pressure is 0.5 MPa,the nozzle is solid 1/4 nozzle,the electric field wind speed is 1.0 m/s,and the fish line is used as the cathode line,the dust removal efficiency is the best.When the coagulant XTG concentration is 1.0×10-2 g/L,the dust removal effect is the best,which is 99%.Studying the electrical performance of gasifier gas dust in the electrostatic precipitator,the rules of corona discharge,dust charge,chemical condensation and dust deposition in the dust collector are found,and the best working conditions of improving the dust removal efficiency are got.It proves that it is feasible to use the electrostatic precipitator to purify the gasifier gas,making the application of the electrostatic precipitator to the purification of gas dust from gasifier a new direction,and providing a reference for industrial applications. |
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