Kinetic analysis of catalytic coal gasification process in fixed bed condition using Aspen Plus

摘要

Coal is one of the energy resources useful for solving the energy crisis. It has met nearly half of the rise in global energy demand over the last decade, growing even faster than total renewables. Catalytic coal gasification is useful technology in SNG (Substitute Natural Gas) and IGFC (Integrated Gasification Fuel Cell) plants that use coal. The Catalytic Coal Gasification Process developed by Exxon in 1978 was simulated with Aspen Plus in the fixed bed type reactor. The purpose of this study is to derive kinetic parameters from experimental results in literature and compare them using the catalytic coal gasification model in Aspen Plus. Carbon-Steam reaction is an important reaction in catalytic gasification reaction since steam is only an oxidant feeding in the system. Mainly, alkali metal gasification catalysts like potassium carbonate increase the rate of steam gasification. The kinetic values calculated from the experimental data are 0.30126, 0.09204, and 0.076995 (cc mol ~1 h ~1). Obtained kinetic value k_f determines k_o and E values compared with Arrhenius equation to input Aspen Plus simulation. Another major focus is on low-rank coal because upgrading low-rank coal is very useful for energy efficiency and environmental aspects. Upgrading coal means removing moisture from low-rank coal. Boiler efficiency is decreased because a lot of moisture content and CO_2 emissions are increased. Carbon dioxide and the flue gas emissions for the same energy level can be reduced by about 30%. Low-rank coal will be increased energy requirement for removing carbon dioxide. The investigation of the drying characteristics of low-rank coal is performed in our laboratory. The experimental results based on the drying characteristics are reflected in this simulation process.