Study On Measurement And Control Technology Of Microreactor In Methanol Reforming For Hydrogen Production Based On Virtual Instrument

Supported by the key project named "Fundamental research on design and manufacture of multi-scale micro-channel reactor for hydrogen production from alcohols" from National Natural Science Foundation of China (Grant No.59030005), aiming at the micro-channel reactor with micro-pin-fin arrays, the measurement and control technology about micro-reactor for hydrogen production from steam reforming of alcohols based on virtual instrument was studied in this thesis. Temperature distributions of the micro-channel reactor with micro-pin-fin arrays, temperature control algorithm and flow control method for the micro-reactor were studied. Then a measurement and control system for the micro-reactor was designed based on virtual instrument and its test software was also developed in LabVIEW. Finally the performances on temperature and flow control of the micro-reactor and reaction efficiency such as conversion percent of alcohols and composition percent of reactant gas under various controlled conditions were studied.In Chapter 1, the background and significance of this research, the current research situation about micro-reactor for hydrogen production from steam reforming and measurement and control technology, the development of virtual instrument and its applications in measurement and control system on micro-reactor were introduced, and then the research contents of this thesis were proposed.In Chapter 2, analysis and optimization for the temperature distribution of the micro-reactor with micro-pin-fin arrays for hydrogen production from steam reforming of alcohols were carried out. Convection coefficient on the surface of micro-pin-fin arrays was calculated and transient heat analysis was carried out to get the temperature distribution of micro-reactor with micro-pin-fin arrays. Aiming at the minimum of difference and standard deviation of temperatures on surface of the reactor support, optimization for position layout of the cartridge heater was achieved and the positions for thermocouples were determined.In Chapter 3, fuzzy auto-tuning on parameters of PID algorithm was adapted to control the temperature of the micro-reactor. The theoretical model of the temperature characteristic of the micro-reactor was established and the model parameters were determined through the experiment identification. According to the tuning principle of PID control of temperature, a fuzzy controller was designed as well as the input parameter's fuzzification and the output parameter's defuzzification, then this temperature control system was verified in Simulink.In Chapter 4, a general measurement and control scheme including control methods of temperature and flow of the micro-reactor based on virtual instrument was proposed. Hardware of the measurement and control system such as type of sensors, connection type of data acquisition card (DAQ) and actuators was selected and configured. Control programs of the temperature using fuzzy auto-tuning PID algorithm, mass flow controller and syringe pump were programmed in LabVIEW using the design pattern of queue-state-machine driven by event, and a graphical measurement and control software with user interaction was developed.In Chapter 5, the experimental setup for hydrogen production from steam reforming of alcohols was built up. Performances on temperature control using fuzzy auto-tuning PID algorithm during catalyst deoxidation and steam reforming and flow control of reducing gas were studied, as well as the reaction efficiency of hydrogen production from steam reforming of alcohols, such as the conversion percent of alcohols and the composition percent of reactant gas under various controlled conditions.In Chapter 6, the chief work of this thesis was summarized, and research objects were proposed in future.