| Biomass pellet fuel is a renewable energy source produced from agricultural and forestry waste materials,which has many advantages such as large reserves,high calorific value,and low pollution,and is an important substitute for fossil fuels.In order to improve the automation level of biomass pellet production and monitor the operating parameters of the pelletizing unit in real-time,and solve the problems of compression chamber congestion and inability to automatically adjust the roll gap due to inaccurate feeding amount in current production,this thesis designs and develops a remote monitoring system based on fuzzy PID algorithm,and conducts system experiments,which mainly includes:(1)Analyzing the problems in the current pelletizing process based on the structure and working principle of the biomass pelletizing unit,it is found that the main reasons for compression chamber congestion are mismatched feeding amount and mixing speed or excessively large roll gap.Based on the problems,the design requirements for the remote monitoring system are proposed.A mathematical model is established for the powder feeding system and roll gap adjustment system in the pelletizing process control,and calibration tests are carried out for roll gap and pressure changes,providing theoretical basis for subsequent roll gap control.(2)A remote monitoring system for biomass pellet machines based on PLC and 5G intelligent gateway is designed,and a remote monitoring system and its interface are designed based on cloud platform.The login interface,system main interface,and production monitoring interface of each submit are introduced,and the functions of historical report display,trend display,and alarm display interface are explained.(3)Analyzing the working process and characteristics of the feeding system and roll gap adjustment system of the biomass pellet machine,a fuzzy PID based control method is proposed,and the fuzzy controller is designed and simulated based on Simulink.The simulation results show that compared with traditional PID,the feeding system designed based on fuzzy PID has an 18.03 ms faster response speed and a 0.112 reduction in overshoot.After adding random interference of ±0.1,the accuracy of the fuzzy PID control within one second reaches 96%,which is 53% higher than that of the traditional PID control.In the simulation comparison of the roll gap adjustment system,the response speed of fuzzy PID is 1.21 s faster and the overshoot is reduced by 0.011 compared with traditional PID.Under sinusoidal interference,fuzzy PID has stronger tracking ability and better overall control effect than traditional PID.(4)The stability of the system and the effectiveness of the feeding and roll gap adjustment systems are verified.According to the experimental results,the system is stable and reliable.The feeding system test shows that the actual current values under various operating conditions fluctuate within the range of 0.01～0.48 relative mean error to the target value,and the coefficient of variation fluctuates between 0.0019～0.5545,which is positively correlated with the set material layer thickness.The roll gap adjustment test shows that the adjustment system is reliable and effective,and the adjustment time under various operating conditions is less than 60 s,and the adjustment error fluctuates within the range of 1～5MPa,which meets the design requirements of the system. |
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