Study On The Electric Control System Of Waste Heat Utiiization Equipment In Bulk Curing Barns

Tobacco baking is important to the quality of tobacco leaf. Nowadays National advocate energy conservation and emission reduction,and sustainable development of tobacco leaf production. More and more attention is paid to the problem of energy consumption during the process of tobacco leaf quality requirement. At present, the barns in Yunnan’ flue-cured tobacco growing areas are mostly bulk curing barns. In the process of tobacco baking, a large number of hot and humid gas is discharged, which not only causes a huge waste of energy, but also affects the environment. In order to make use of the waste heat of the hot and humid gas, the experts and scholars have designed the heat exchange device for the bulk curing barn. After installing the heat exchanger, waste heat recovery rate reaches 26.56%, and the energy saving effect is remarkable. However,because of the increase in wind resistance, humidity outlet appears to be a problem of poor drainage of moisture, which affects the quality of tobacco leaves. At the same time, waste heat utilization system still needs manual control.In view of these problems, combined with the actual situation of Yunnan Province, this paper mainly carried out the following aspects of the work:1. Deeply studied the structure, baking process and heat exchanger of the bulk curing barn.2. On this basis, we designed an electronic control system of intensive use of waste heat based on STM32 microcontroller which realized automatic control to the cold air inlet damper, heat exchanger throttle and the fan in the humidity outlet. Through optocoupler and AD conversion to the action signal in cold air inlet from control host of flue cured tobacco house, we got the system instruction code. We also designed a blocking current detecting circuit which could effectively distinguish whether the door in humidity outlet opened to the maximum. According to the state of the controlled object and the instruction code, the state analysis method is adopted to meet the requirements of the control logic. Meanwhile, we use the control of H bridge to realize the positive and negative control of the motor.3. Studied the frequency conversion to the small power motor in order to reduce the energy consumption and prolong the service life of the exhaust fan and we realized the output of pulse width modulation waveform.4. Debugged and verified the hardware and software by experiments to the electronic control system.Through the test, the design of the electric control system can basically realize the automatic control of the waste heat utilization system of the bulk curing barn and properly solve the problem of poor drainage after the installation of energy-saving emission reduction device in the exhaust.