Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 103 === In this study, we discuss two slurry systems, water and liquid carbon dioxide, in an Integrated Gasification Combined Cycle process. And the influence of slurry change on syngas production and energy analysis. Because the high heat capacity and high enthalpy of vaporization of water, these would lead to a low efficiency in gasifier. In order to improve the gasification efficiency, liquid carbon dioxide, CO2(l) has been proposed instead of coal-water system in the IGCC system with carbon capture.
Using Aspen Plus to simulation the IGCC process, including gasifier, water-gas shift reactor, acid gas removal and carbon dioxide capture. Reference to the National Energy Technology Laboratory (NETL) report in 2012, rebuild the coal-water slurry model. Then change the slurry medium to liquid CO2(l) and compare the differences between these two systems. The result shows that at the same coal conversion, the syngas HHV in CO2 slurry system is 8.63 % higher than water slurry system. The cold gas efficiency increased about 6.84 %. Therefore, liquid carbon dioxide slurry is helpful for enhancing the gasification efficiency. In addition, the H2 production in CO2 slurry system is 8 % higher than water slurry system, the amount of CO2 capture also increased about 10 %.
This study also discusses the influence of main parameters of the gasifier in CO2 slurry system, such as solids loading, oxygen to carbon ratio. The results shows that increasing the solids loading and oxygen to carbon ratio will improve the syngas HHV and cold gas efficiency.
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