| Drying is a key step in the production process of many industries,which consumes more energy and produces air pollution.Therefore,energy conservation and emission reduction of dryer is a key research area.According to the analysis of the structure and principle of dryer,one of the important ways to save energy is to recover the heat lost in the drying process.The traditional dryer heat recovery technology mainly uses heat exchanger,heat pump,organic Rankine cycle and other equipment,but these technologies have defects.For example,the heat exchanger needs to consider the geometric dimensions,so its compatibility is poor.The heat pump needs regular maintenance,and the structure of the organic Rankine cycle is relatively complex and its reliability is low.On the other hand,in view of the problem of air pollution caused by dryer exhaust gas,the traditional dryer dust removal technologies are mainly electrostatic dust removal method and wet dust removal method,which require high-voltage power supply and blower,consume a large amount of power and generate noise.The report of the 20th National Congress of the Communist Party of China pointed out that“accelerate the research and development,promotion and application of advanced technologies for energy conservation and carbon reduction”.Thermoelectric generator(TEG)is an energy-saving technology that converts heat into electrical energy,which has the advantages of noiseless,high reliability,maintenance-free,and good compatibility,which can solve the above problems.Therefore,this paper designed a thermoelectric power generation and exhaust gas purification device for heat recovery of electric heating dryer.First,this paper starts from the structure of the dryer,determines that 2 heat sources(heating box wall surface and dryer exhaust gas)can be used for thermoelectric power generation,and analyzes the energy flow of the dryer and the installation of thermoelectric power generation device.The specific heat recovery and utilization plan of the 2 heat sources is as follows:the heat from the wall of the heating box is converted into electrical energy through thermoelectric cell and stored in the battery;The heat of the dryer exhaust gas is converted into electrical energy and supplied to the negative air ions generator with dust removal function.Secondly,complete the design of the thermoelectric power generation device installed on the heating box of the dryer.In consideration of the smooth operation of the modified dryer,Fluent was used to simulate the dryer heating box before and after the installation of the thermoelectric cell.The simulation results and test results showed that the installation of the thermoelectric cell on the dryer heating box had no obvious effect on the efficiency of the dryer;Since the recovery scheme is to convert the heat on the wall of the heating box into electric energy and store it in the battery,it is necessary to control the output voltage of the thermoelectric power generation device.According to the design index,complete the design of the controller(STM32F334)and DC-DC circuit,and test its performance;Further build a test platform to test the parameter characteristics of the device.The test results show that when the dryer heating power is.3 0 k W and the wind speed is12 m/s,the corresponding optimal water flow is22.3 L/min,at this time,the power consumed by the water pump is6.4W,the device output power is 31.8 W,the maximum value of net output power is25.4W,and the thermoelectric conversion efficiency is9.3%.Finally,the design of thermoelectric generator and exhaust gas purification device for recovering the heat of dryer exhaust gas is completed.The recovery and utilization scheme is to convert the heat of dryer exhaust gas into electric energy and supply it to the negative air ions generator with dust removal function.Through Ansys,LTspice,Multisim14.3 and other software,complete the design of thermoelectric power generation module,voltage stabilizing circuit and negative air ions generator circuit;Build a test platform to test the purification performance of the device.The test results show that when the dryer exhaust gas temperature is 55℃and the relative humidity is 90%,the concentration of negative air ions produced by the negative air ions generator with output voltage of-10.5 k V is 5.87×10~6ions/cm~3,dust removal efficiency is about82%.To sum up,the thermoelectric generator and exhaust gas purification device for heat recovery of electric heating dryer designed in this paper provides a new idea for the field of energy conservation and emission reduction of the drying device.While recovering the heat lost during the drying process through thermoelectric generator,the negative air ions generator is introduced to purify the dryer exhaust gas,which plays a certain role in promoting the development of advanced technologies for energy conservation and carbon reduction. |
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