| Summary: | 碩士 === 國立中央大學 === 環境工程研究所碩士在職專班 === 98 === This research takes the fixed coal fired pollution source located in Tao-yuan area as the object of study. It sorts out 2 types of boilers as large-scale and medium/small ones for comparing its historical records of emission to find out the variation of emissions created by different sizes of boilers and control equipment. Second part of the study is based on on-job site research of stack emission from coal-fired boilers and its intensity for affirming the difference of efficiency of control equipment and operating parameter. The results obtained will provide reference data for environmental protection administration to take regulatory control and boiler-user’s daily operation. According to the emission analysis of stack gases, because of the requirement of Environment Impact Assessment and stricter restriction of flue gas emission standard, large-scale coal-fired boilers are generally equipped with efficient control facilities including electrostatic precipitator (EP), flue-gas desulfurization (FGD), and selective non-catalytic reduction (SNCR), and most of big-size boilers can meet current emission standards. As far as medium/small size of coal- fired boilers are concerned, in view of less stringent emission standard, their control equipment are generally less effective and the results exhibit larger variation of emissions. The average emission factor of SOx for co-generation boilers is 0.42 (kg/ton coal burned) and the emission factor of NOx is 0.41-1.58 (kg/ton coal burned). The results obtained reflect that the removal efficiencies of control equipment for particulate matter of coal-fired boilers of Plants A and B reach 94.87% in average which is higher than that of Plants C and D, being 64.16% in average. The cyclone shows good control efficiency of particulate matter in medium/small size of coal fired boiler but the efficiency decreases significantly as the gas flow rate increases. The removal efficiency of SOx reaches 93.82% at Plant D in which the control equipment of scrubber operated at the highest L/G ratio among the four plants investigated. However, no obvious relationship is found between the operating parameters and NOx removal efficiency possibly due to the low solubility of NOx in scrubbing liquid.
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