Hydrogen Leak Detection Technology Research Based On Multi-sensor

As the clean energy with high combustion efficiency and less pollution, hydrogen has been widely applied into chemical industry and the fields of aerospace and military practice. Hydrogen molecule is so tiny that it’s likely to leak during the process of manufacture, transportation. Meanwhile, it will lead to explosion when the concentration of hydrogen in the air is more than4%. As to the hydrogen leakage in the manufacture, transportation and storage, this paper conducts the study on a multi-sensor techniques for hydrogen leak detection.With reference to the technical qualifications, national regulations, the applications of the system and some other relevant factors, the main technical qualifications of this system is established. General design of the system is obtained and the components of the system are introduced. Meanwhile,the detection principle and functions of system’s components are discussed. The system takes metallic-oxide hydrogen sensors into practice after the analysis of the characteristics of different sensors. The sensitivities and response characteristics of the sensor are analyzed. As the sensor has the drawbacks that temperature change will inluence its sensitivities, its temperature characteristics are studies based on the analysis of experimental data. At the same temperature, different sensors has similar change rates of resistors in pure air, the division of resistor and standard resistor. The temperature compensation is accomplished with subtraction of resistor change rate between the detective sensors and reference sensors. Consequently, the influence of temperature change to the leakage measurement is reduced. The multi-sensor test data is processed by means of a method based on the batch estimation fusion of single sensor and the grouping adaptive weighted fusion of sensors. As indicated by the simulation data, the processing results of the methods put forward are closer to the real data.With MSP430F149as the control unit, the data acquisition are realized. The working circuits of sensors, second-order low-pass filer, the power switching circuits and the serial port communication circuits are designed. The circuits of the system are tested by the intrinsic safety regulations. After the design of hardware, the program of A/D and serial port communications of slave computer are worked out. Then the program of serial port communication, data acquisition and display, temperature compensation,calculations of hydrogen concentrations and the data fusion of upper computer are worked out by the software of LabVIEW. The test of detection system’s working performance is accomplished. The hydrogen’s influence to sensors is simulated by adding a parallel resistance to sensors. The performance of system’s temperature compensation and data fusion is tested.