Experimental Research On Desulfurization Of Small-Scale Circulating Fluidized Bed Boiler

With the increasingly stringent requirements on environmental protection, it is particularly important to reduce the emission of SO₂ for the protection of environment. With its high efficiency and low-pollution combustion, the technology of circulating fluidized bed has been popular all over the world. The combustion technology of circulating fluidized bed is bound to become the emphasis in the development of coal-fired technology in the future no matter from the comparison of all kinds of clean coal combustion technologies or from the current development status of China's economical development. Therefore, in-depth study on circulating fluidized bed desulfurization has practical and far-reaching significance on energy conservation and environmental protection of China.Through combining with the boiler reconstruction project (reconstruction of 15t/h circulating fluidized bed boiler of Luzhou Laojiao) undertaken by Sichuan Provincial Energy Conservation Technology Service Centre, experimental research on desulfurization is carried out. The optimal operating temperature (890 to 900℃), Ca/S molar ratio (1.9) and circulating ratio (15) are obtained, which provide favorable references for the desulfurization of small-scale circulating fluidized bed boiler. By integrating the previous researches, the mathematical model for the variation of desulfurization efficiency of small-scale circulating fluidized bed boiler with temperature, Ca/S molar ratio and circulating ratio is established.According to the variation curve of desulfurization efficiency with the influences of boiler operating bed temperature, the following formula is obtained:The relationship between the desulfurization efficiency and Ca/s negative exponential growth, that is,The relationship between the desulfurization efficiency and the circulating ratio Ris:Under the joint influence by boiler bed temperature T and Ca /S molar ratio, bed temperature T and circulating ratio R, the desulfurization efficiency will be: A fine match is obtained through comparing between the results calculated by the model and the testing date, and the reliability of the tests and models is verified. In view of influences to boiler efficiency by desulfurization, the thermal efficiency of the boiler was tested during the process of desulfurization. The tested result is compared with the one not under desulfurization. The thermal efficiency of the boiler slightly decreased, but the output of the boiler is not affected basically. Finally, economic analysis of the boiler transformation and desulfurization is carried out, and valuable advices are provided for the development of small-scale circulating fluidized bed boiler.