The Study And Design Of Sulfur Dioxide Density Monitor System Based On Double Frequency Difference Method

Sulfur dioxide is one of the major pollutants in air, which mainly comes from coal burning of power plant. It is very important of monitoring sulfur dioxide from smoke to control and father sulfur dioxide.Today the physical method, which seems to be more effective and efficient, tends to take the place of the chemical measurement. Based on the analysis and compare to measure technology of observation apparatus of sulfur dioxide concentration, this paper studies the technology of UV fluorescence of sulfur dioxide rooting in the practice of the monitor of sulfur dioxide. As fluorescence is likely to be influenced by the light source fluctuation and the temperature of the sample, based on the academic foundation of linear connection between sulfur dioxide concentration and fluorescent intensity in stated range of concentration, this paper gives a new scheme, which used to resolve the question of fluorescence signal, to measure the concentration of sulfur dioxide by two different frequencies according to correlation theory.This system uses the deuterium lamp as its blazed lamp-house, and makes mechanical turnplate in use of modulating light signal with two frequencies, which is drived by in-phase electromotor with constant velocity. A potomultiplier tube is used to conversion optical signal to electric signal. Using Lock-In Amplifiers to realize magnifying the metrical signal using difference method with two different frequencies. We also analyze its principle of each part of the apparatus and design the realization circuits of each part. The data analysis and the in-phase electromotor control circuits are fulfilled by SCM; the single chip control system's hardware interface and software design are given.Finally, through experiment and data analysis of this system conforms to academic deduction. This proves that the system has reasonable and feasibility design and good practical value.