報告書番号

W02004

タイトル（和文）

ガス化炉内現象数値解析ツールを用いた空気吹き石炭ガス化炉の性能予測 -ガス化剤酸素濃度と水蒸気投入量のガス化性能に及ぼす影響評価-

タイトル（英文）

Prediction of Air-Blown Entrained Flow Coal Gasifier Performance using Numerical Simulation Technique-Effect of Oxygen Enriched Air and Steam Injection on Gasification Performance-

概要 （図表や脚注は「報告書全文」に掲載しております）

空気吹き石炭ガス化炉において、ガス化反応を促進させ、生成チャー量を低減できれば、システムの高効率化やコンパクト化が可能となる。そのための手法の一つとして、酸素富化運転による炭素転換率向上策が検討されている。酸素富化運転は、酸素濃度が高くなると炉内が異常な高温になるため、水蒸気投入による温度制御が必要になる。そこで、数値解析により酸素濃度と水蒸気投入量が炉内ガス温度とガス化性能に及ぼす影響について調査した。その結果、酸素濃度の増加に伴う炉内温度の高温化により炉内炭素転換率が向上すること、水蒸気投入によりリダクタ内炭素転換率が上昇するためコンバスタ出口炭素転換率の低下にもかかわらず炉内炭素転換率は僅かな減少にとどまることが分かった。また、数値解析から得られる酸素濃度、水蒸気投入量に対するコンバスタ温度と炉内炭素転換率の分布から、同一空気比での安定運転と炉内炭素転換率向上のための指針が得られた。

概要 （英文）

Promotion of char gasification reactions and reduction of the amount of producted char are effective for making to highly effective and compact of air-blown IGCC system. An operation with oxygen enriched air is examined as a solution for an improvement of carbon conversion efficiency. In case of increase of the concentration of oxygen in gasifying agent, gas temperature in the gasifier rises much higher than 2300[K]. In such a condition, a temperature control by steam injection will be needed to avoid a molten ash adhesion on the inner wall of gasifier and to decrease thermal loads of the parts of the gasifier. Therefore, three dimensional, gas-particle reacting flow numerical simulation was carried out under one air ratio and eight conditions of the concentration of oxygen in gasifying agent and the steam flow rate to predict an effect of the concentration of oxygen in gasifying agent and the steam flow rate on the gas temperature and gasification performance. As a target of the calculation, 2 t/D entrained flow air-blown coal gasifier of CRIEPI was selected. As a result of the calculation, as the concentration of oxygen in gasifying agent increases the per pass carbon conversion efficiency increases because of the increase of the gas temperature in the combustor. As the steam flow rate increase, the per pass carbon conversion efficiency stays in a little decrease, though the carbon conversion at combustor exit decreases because of the promotion of char-steam gasification reaction. It was confirmed that a guideline for the stability operation and increase of the carbon conversion efficiency was obtained by evaluation of the combustor temperature distribuion and the carbon conversion efficiency distribuion on the figure of the oxygen concentration versus the steam flow rate.

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