Study Of Numerical Simulation Method For Gas Flow Distribution Of The Embedded Electrostatic-bag Precipitator

With the improvement of flue gas dust in atmospheric pollutants emission standards in recent years, he coal-fired power plants need to use more efficient equipment to reach the new emission standard. At present, the embedded electrostaticbag precipitators has the characteristics of high adaptability for the difficult coal and high resistivity dust. As the high efficiency dust removal equipment on the promise of guarantee the filtration wind speed, has been widely used the existing and new reconstruction project in coal-fired power plants. The internal flow distribution is the key technical problems in large embedded Electrostatic-bag precipitators, directly related to resistance loss of equipment and the service life of filter bag.In order to optimize the internal flow field of dust collector numerical simulation method was used in this paper. on the basis study the internal air distribution of Electrostatic and Electrostatic-bag precipitators, a coal-fired power plant unit #4embedded electricity composite filter bag as the object of the study, the internal flow distribution was analyzed by numerical simulation methods, entrance velocity uniformity of the first electric field, rising velocity uniformity of bag, air flow distribution of the filter bag unit and the resistance loss of equipment were calculated by using numerical simulation mainly. The internal flow simulation of filter was analyzed measures of the optimized improvement measures were presented. While, the internal air flow situation and the change of resistance loss of equipment on different load conditions were studied. The main conclusions are as follows:1. The results show that internal air flow field distribution uniformly in electric field unit of electrostatic-bag precipitators after optimized, and the relative root meansquare value ? =0.24, meet the requirement of air distribution design and made charged fully in the electric field cell, achieved high removal efficiency.2. A uniform air distribution on each cell of filter bag, the maximum deviation was less than 2%, reached the 10% of the design requirements. The updraft speed well achieved 1.18 m/s and far less than the design requirements of 1.5 m/s in filter bag. It reduced the updraft velocity, avoided secondary dust adhesion, reduced the resistance loss of equipment through optimization measures.3. With the increase of load conditions, resistance loss of equipment also increased rapidly, so the relationship between load and resistance was obtained.This relationship could provide a reference for the calculation resistance loss of the dust collector system could under the condition of different working conditions.4. The results of numerical simulation has been applied in engineering 300 MW boiler unit. The equipment operation was stable and reliable after the embedded electrostatic-bag precipitators were put into operation, the running resistance loss of equipment is 683 Pa, the concentration of pipeline export carbon is less than 20 mg/Nm3 and meet new dust emission standard. The practicability of numerical simulation method has proved fully through engineering application, and it contribute to the numerical simulation method popularize and apply in the large-scale of electrostaticbag precipitators.