Modification And Research Of PMG For Slurry Circulation Pump In Pingshan Power Plant

With the gradual promotion of environmental policies such as "carbon peaking and carbon neutrality," the cost of thermal power generation has gradually increased,requiring the development of new profit models such as deep peaking,blending with low-quality coal,and lowering plant electricity consumption.In the context of such cost savings and pollution reduction,the Pingshan Power Plant staff discovered that there was still a significant potential for energy savings in the desulfurization system,so the Pingshan Power Plant decided to retrofit the slurry circulation pump 2B with a permanent magnet after weighing all of the options.This project takes advantage of the permanent magnet retrofit opportunity at the Ping Shan Power Plant to develop and research the high-power disc-type permanent magnet governor in terms of equipment classification,working principle,theoretical modeling,software simulation,and actual energy savings effect.The following are the specifics:Initially,a mathematical model of the disk-type permanent magnet governor is developed based on the equipment’s construction and operation.The output torque and eddy current loss equations are solved using the mathematical model.We can observe from the analytical equation: the impact of each PMG primary parameter on output torque and eddy current loss;and the correlation between output torque and eddy current loss.This serves as the theoretical foundation for the subsequent finite element simulation.Second,Ansys Maxwell performs modeling simulation to study the magnetic field distribution,eddy current loss distribution,and eddy current density distribution law of the permanent magnet governor based on the aforementioned equation set and existing equipment characteristics.Further investigate the effect of inner and outer radius of conductor disk,thickness,number of poles,length,width,and thickness of permanent magnet on output torque and eddy current loss using the distribution law,obtain better equipment parameters,re-establish the optimized 3D model,and compare it to the preoptimization.Again,the electromagnetic and thermal coupling simulation function of Ansys Workbench software is used to analyze the maximum temperature and temperature distribution of the permanent magnet governor during long-term operation before and after optimization.After the simulation,it was found that before optimization,the maximum temperature of the conductor disk with natural air cooling exceeded the national standard,and the maximum temperature of the conductor disk could be reduced to 43℃after adding thin oil cooling;after optimization,the area of the permanent magnet increased and the thickness decreased,the convection heat dissipation effect was enhanced,and the temperature of the permanent magnet decreased significantly,but the conductor disk still did not meet the requirements of the national standard,and the attached cooling equipment was needed.Finally,according to the national standards,installation and commissioning,after acceptance and put into trial operation,the actual speed range of permanent magnet speed regulation in this project was found to be 50-100% during the trial run.After the trial run,the daily adjustment proves that the permanent magnet governor can achieve the expected energy saving effect in the application of desulfurization absorption system,and the cost can be recovered in about 3 years according to the static recovery method.