| Sulfur dioxide is the air pollutant, the main source of sulfur dioxide were fossil fuel burning and industrial emissions. China's main fuel is coal, coal gene rally contain 1% to 8% of the sulfur. Therefore, the concentration of sulfur dioxide in industrial boilers and coal-fired furnaces was as high as exhaust 3ppt. Serious polluted the atmospheric environment, The situation was attached great importance to the national environmental agency. Accurate measurement of its content is the primary means of air pollution detection. Based on the sulfur dioxide gas under UV irradiation, excite the certain wavelength fluorescence, with optical fiber sensing technology, using fluorescent differential method, developed a system of detecting concentrations of atmospheric sulfur dioxide. measurement error≤3%, good stability and high precision and strong anti-interf- erence ability.The main research works are as follows:According to principles of fluorescence, combine with fluorescence spectro scopy of sulfur dioxide, choose the best excitation wavelength of sulfur dioxide. using a new method-fluorescence differential process the fluorescence signal. With two chamber design, eliminates background noise. Improve the measureme nt accuracy.According to the excitation wavelength and fluorescence wavelength of Su- lfur dioxide, a reasonable choice of laser light source, quartz lenses, filters, air c- hamber structure, photomultiplier tubes, fiber and so on. Makes the system can accurately measure the concentration of sulfur dioxide.Designed and described weak signal detection system, principle of filter, amplifier. chose the right amplifier and filter. Main parameters were explained. At the same time dealing with computer hardware design. Select PIC16F877 microcontroller as the core component of the system to process data. Keyboard, display system, communications system were designed and descryipted. The experiment proved the feasibility of system.
|
PDF Full Text Request