| Flue-cured tobacco,as a traditional agricultural cash crop and special agricultural product,is an important pillar of China's economic industry and plays an important role in China's economic prosperity,GDP growth and poverty alleviation of rural poor.Tobacco industry brings great economic benefits,but also brings some environmental problems.In the past,tobacco straw was mostly treated by burning in the field.On the one hand,straw burning seriously polluted the atmosphere,and on the other hand,the special ingredients contained in tobacco straw doomed that tobacco straw was not suitable for returning to the field on the spot.In the long run,it would cause irreversible damage to the soil fertility.On the other hand,the development of new energy sources is an effective means to alleviate the current problem facing the whole world--fossil energy depletion.The development and utilization of new energy sources has become the focus of the whole society.As an important new energy source,biogas has the characteristics of clean,simple technology and high calorific value.The most important thing is that it can degrade and consume waste biomass efficiently in the biogas production process and solve the problem of waste disposal.The biogas utilization of tobacco straw can bring considerable economic benefits while efficiently and environmentally friendly treatment of tobacco waste.Starting from the basic laboratory experiments,this paper explores the effects of different fermentation temperatures(25?,35?,45?)and material ratio on the fermentation characteristics of tobacco straw.The research found that: compared with the influence degree of material ratio on the fermentation effect of tobacco straw,the influence of temperature was more severe,showing that the higher the fermentation temperature was,the better the fermentation effect.It was concluded that the fermentation temperature was the decisive factor affecting the fermentation effect of tobacco straw biogas.On the basis of the above conclusions,Fluent simulation and temperature control system design were carried out for the temperature field in the industrial biogas fermentation tank.A biogas fermentation tank in Cheng Du,Si Chuan province was selected as the simulation object.The physical model was established by using PROE,and the temperature field distribution in the tank was simulated by using ANSYS/Fluent.The MRF model of multiple reference frames was selected,and the area around the stirring blade was set as a moving region,with a rotating coordinate system,while the other regions were set as a static region,with a stationary coordinate system.The grid is divided automatically.The total number of grids is 12759122 and the number of grid nodes is 2751030.The results showed that there was no significant difference between the FUENT simulation results and the experimental results at the significance level of 0.05 at the time of 6600 s.Based on the simulation results,a temperature measurement point arrangement scheme was proposed.According to the biogas fermentation temperature dynamic characteristics such as nonlinearity,more interference,large hysteresis characteristics,the immunity temperature Control scheme is presented in this paper,fermentation temperature since the immunity Control(the Active Disturbance Rejection Control,ADRC)system design and analysis,in order to easy to implement and has extensive applicability of the setting method of optimization of ADRC controller parameters,using mathematical tool MATLAB/Simulink configuration simulation system,Under the same condition,the ADRC is compared with the traditional PID and cascade PID control which are widely used in engineering.The results show that the ADRC has better tracking and anti-jamming ability than the traditional PID and cascade PID,and shows stronger robustness.The results of this paper show that the ADRC has a certain application prospect in the control of biogas fermentation temperature. |
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