Development Of Heat Exchanger Coating And Design And Calculation Of Tube Bundle Heat Exchanger Of Coke Oven Gas

Coke-oven raw gas produced by coking production had lots of residual heat resource,accounting for 36% of coking process energy consumption,which had enormous energy-saving potential.However,in the existing technology of waste heat recovery,it was still in the stage of research and exploration because the problems of tar adhesion and corrosion,and the efficiency of existing heat recovery equipment generally was low.Designing new heat exchanger and using heat exchanger coating technology of non-stick and anti-corrosion,could effectively solve the problem of low heat transfer efficiency and tar adhesion,but due to the limit of high temperature in the working environment,improving the temperature resistance and the hardness of the coating were particularly important.Modified polysiloxane,silica and the molybdenum disulfide were composited respectively in the PTFE-based resin paint,modified non-stick paintwas prepared,non-stick coatingwas sprayed and fired,and the hardness,thickness,tarcontact angle,temperature resistance,adhesion of modified coating were tested.The method of applying MATLAB software to process the color image of coating in high-temperature was innovative,the defect rate was calculated to evaluate the properties of the coating.The results show that the hardness of the coating and the contact angle of tar are increased by adding three modifiers to the PTFE based resin coating when the content of modifiers and the thickness of coatings are controlled.The results of image processing show that the defect rate is decreased to below 4% from 8% by adding modified polysiloxane and controlling its content in 0.2% to 0.8%,the thickness in 20um~30um,meanwhile in the higher temperature(about 350 ?),a better coating performance and surface quality are obtained;it is further show that adding modified polysiloxane,with an appropriate extension of the high temperature firing time help to reduce the defects of the coating surface,and can improve the coating resistance temperature and viscous resistance.A new heat exchanger has been designed and developed,the shortage of low efficiency in the existing coke raw gas waste heat recovery technology has been overcomed,the temperature of coke raw gas has been reduced from 750 ? to 250 ?,the recovery of raw gas heat in a small space efficiently has been achieved,the problem of tar adhesion has been solved and no tar adhesion on the heat transfer surface or heat channels has been achieved too.The new raw gas heat recovery system,can produce an annual amount of steam 22.32 ten thousand t and obtain economic benefits of 17.86 million yuan per year.In addition,the simple numerical simulation on tube bundle heat exchanger is conducted,the results are almost consistent with the thermal calculation,and it show that when the heat exchanger is running,the maximum temperature of tube wall of heat exchanger is 250 ?,in theory,there will not be the phenomenon that the temperature is too high to cause the coating failure.