Research On Preparing Conditions Of Wear-resistant Composites In FGD System

The desulfurizing slurry-circling pump as the core power part of FGD has been facing corrosion,erosion and cavitation erosion which is caused by desulfurizing cycle serious in the working process for all the time,and the working environment is very rough.As the reason that the metal impellers generally have a very short working life,a lot of researches have shown using composite material instead of metal material to make the flow passage components is a low-cost solution to improving the pump's working life.The epoxy resin matrix composites have a high mechanical performance,high resistance to wear,small curing shrinkage rate after its curing.It can be a good molding and coating material.By study on the epoxy resin matrix composite filled with mixed particles' curing rheological properties,curing reaction and the mechanical properties which are after cured,we established a suitable plan for its molding process and also a better way to solve the slurry pump 's wear problem.First of all,make a curing rheological test for the epoxy resin matrix composite filled with mixed particles to detect the gel point temperature in the process of curing.Use Castro and Macosko's experience equation to describe the changes in the relationship among the viscosity of curing system,temperature and the degree of curing,then compare the relationship with the actual situation to set up the suitable rheological model.Mark the holding time,the range of temperature and the suitable heating rate when the viscosity of curing system is in 200~800m Pa·s.From above research,we can get the suitable curing time and curing temperature for different molding techniques and provide a theoretical guide for practical operation.Second,a differential scanning calorimetry(DSC)was done for the curing reaction process of the epoxy resin matrix.A kinetics model function for the curing process was set up and we identify the reaction process as an autocatalytic model at the end.Through the model function,we describe the relationship among the curing degree,the reaction temperature,the reaction rate and the reaction activation energy.Three characteristic temperature of the curing system were obtained by using extrapolation method,and for this reason,the process of ladder curing method was optimized.The effect of mixed particles which is filled with the epoxy resin and the surface modification of the particles was detected through the above data,and the results suggested the two ways are both not changing the mechanism of the curing reaction of the epoxy resin system,but the mixed particles will increase the reaction barrier of the curing process and the surface modification which adds silane coupling agent will decrease the effect of the reaction barrier.The research which relates the parameters of the curing reaction temperature,fillers and additives provide a guiding basis for the actual choice in the real preparation method of the epoxy resin system.Finally,the thermal dynamic mechanical analysis(DMA)was done for the epoxy resin specimen which is cured.Through the data of mechanical modulus and glass transition temperature,we study the mixed particles and the surface modification of particles' effect on the mechanic performance of the cured specimen.The results show the two ways can greatly improve the epoxy resin cured system 's modulus of elasticity and hardness.The results also verified the post curing and the ladder curing which uses a high temperature do not have an obvious effect on enhancing the mechanic properties of cured specimen and that shows the current ladder curing temperature which we use in the laboratory can make the epoxy resin filled with mixed particles complete cured.In conclusion,through the different methods of thermal analysis to study the curing process of the epoxy resin system,the reasonable parameters of the curing process are determined,the different molding process designs' effect on the mechanical performance of compound material have been compared.Based on all research,we believe that the epoxy resin matrix material filled with mixed particles can replace metal material for making the impellers of the slurry-circling pump or the surface of the impellers.