탄산칼륨 촉매 사용 시 석탄 종류에 따른 스팀 촉매가스화 범용 모델 개발 및 합성가스 생성 특성 파악을 위한 연구

Abstract

This study discusses catalytic coal gasification, which is one of the clean coal technologies. Catalytic coal gasification uses a catalyst for the coal gasification reaction at lower temperatures, as opposed to the high temperature conditions usually required. Sufficient carbon conversion at low temperature can be obtained using a catalyst that enhances the reaction rate. This strategy also has a favorable effect on methane production. Many studies on catalytic coal gasification were performed during the late 1970s and throughout the 1980s. The efforts made to simulate the whole process were unprecedented. In this study, the catalytic coal gasification process, which has heat usage advantages, will be used as the basis for the construction of a demonstration plant by performing a simulation.

Simulation of catalytic coal gasification was performed using the following steps. Initially, experimental data for catalytic coal gasification were explored in the literature and the catalytic mechanisms of coal gasification were studied when using a catalyst. Then, the simulation performance was carried out by considering the increase in surface area, which leads to an increase in active sites for the channeling action of catalysts. It is based on the assumption that increases in the reactivity of catalytic coal gasification is increased by the active sites through the channeling phenomenon.

The reactor model was constructed by checking the mass balance for each of elements given the reactor type and size, analysis of the results for coal, steam and mixture amounts, and syngas composition. In addition, heterogeneous and homogeneous reactions were separated into different reactor models. Reactor models were used for continuous stirred tank reactor and plug flow tubular reactor models, which were selected in consideration of the physical and chemical reaction phenomena. Reaction rates applied to the reactor model were calculated experimentally and expressed using the heterogeneous equation, which considers various parameters for coal as a solid fuel. Furthermore, the Langmuir-Hinshelwood adsorption reaction equation was adapted to indicate the adsorption and desorption phenomena of steam on the surface of coal char. Further, the catalytic coal gasification model was constructed by considering the heat transfer from the exothermic reaction in the homogeneous reactions to the endothermic reaction in the heterogeneous reactions and the heat loss in the actual gasifier. Heat transfer was used as the heat source for the solid coal char and potassium carbonate.

The catalytic coal gasification process model was validated from experimental results in the Exxon report and was confirmed with carbon conversion, cold gas efficiency, and syngas composition. The basic model was completed by comparing the actual experimental result with the simulation results, and different coal types were chosen to check the common model as a single case. In order to expand the available model into a general model, additional work would be required to develop more experimental data and coal parameters by matching experimental and simulation results.