Optimization Design Of Hot Blast Stove For Small Grain Dryer

With the increasing of mechanization degree in agriculture production,the problem of grain drying is becoming more and more serious.In particular,the research on the hot air stove used for grain drying is becoming more and more important.Under the background of the country’s five development ideas,transformation of coal-fired hot blast stove into hot blast stove with biomass as fuel has more social value.The hot blast stove using biomass can not only reduce the cost of food drying,but also reduce pollution.It is more suitable for the vast rural areas in China.The main components of the hot blast furnace in this thesis include biomass gasifier,burner and heat exchanger.Firstly,the classification of them is introduced in detail.On the basis of analyzing the working principle and characteristics of various biomass gasifier,burner and heat exchanger,the fixed bed downdraft gasifier,blast gas combustor and shell and tube heat exchanger were selected as the design plan.On the basis of selecting the various components of the hot blast stove and combining with the requirements of the small grain dryer,the structural parameters of the three components of the hot blast stove were designed by theoretical calculation.Through the above theoretical calculation,the basic dimensions and boundary conditions of the burner were obtained.Numerical simulation of gas combustion in the main part of the burner was done on the basis of FLUENT software.By changing the excess air coefficient to study the effect of the amount of air intake on the combustion characteristics of gas,to find out the optimum structural parameters of the air and gas entrance.Based on the theoretical calculation and numerical simulation of burner,the basic dimensions of the heat exchanger,the boundary conditions of the basin and the boundary conditions of the tube were obtained.The heat transfer performance of heat exchanger tubes with different shapes was analyzed and compared,the heat transfer performance of corrugated pipe is the best.The influence on the heat transfer performance of concrete structure parameters of corrugated pipe was analyzed and the best value was selected.Study on the heat pipe shell are as follows.The numerical simulation results of the shell side structure with the baffle plate and the shell side structure without the baffle plate were analyzed and compared.It is concluded that the heat transfer performance of the shell side structure with the baffle plate is more excellent.The specific structural parameters of the baffle plate were optimized by the numerical simulation analysis method.The optimization design of the hot blast stove was completed by theoretical calculation and numerical simulation method.