報告書番号

W99026

タイトル（和文）

石炭ガス化中カロリー燃料用ガスタービン燃焼技術の開発 -基礎燃焼特性と燃料ノズル包囲型窒素直接噴射燃焼器の基本性能 -

タイトル（英文）

Study of Combustion Technology for Medium-Btu Fueled Gas Turbine in IGCC-Combustion Characteristics of Medium-Btu Fuel and Performance of Combustor with nitrogen-direct injection which surrounds fuel nozzles-

概要 （図表や脚注は「報告書全文」に掲載しております）

酸素吹き石炭ガス化中カロリー燃料のプラント熱効率に優れる低ＮＯx・安定燃焼技術の確立を目的として、プラント余剰窒素を燃焼器へ直接に供給する方式を提案した。本方式は従来の方式に比較して熱効率を約0.3％（絶対値）向上すると共に、ＮＯx生成を大幅に低減する。また、小型拡散バーナを用いた燃焼実験により窒素供給位置ならびに供給量が中カロリー燃料の燃焼特性に及ぼす影響について把握すると共に、ここで得られた知見を基に、燃料ノズルと空気ノズルの間に窒素供給ノズルを有する燃焼器を設計、試作し、燃焼試験により性能を評価した。その結果、燃焼安定性を確保しつつ、ＮＯx排出濃度は8ppm(Ｏ2濃度16％換算)以下、燃焼効率ほぼ100％、燃焼器壁面温度は材料の耐熱許容温度以下に抑制できることを確認した。以上のことから、湿式ガス精製を採用する石炭スラリー搬送･酸素吹き石炭ガス化中カロリー燃料用ガスタービン燃焼技術を開発できた。

概要 （英文）

The flame temperature of oxygen-blown medium-Btu coal gasified fuel is higher and so NOx production from nitrogen fixation is expected to increase significantly. We have started to develop low NOx and stable combustion technology using medium-Btu coal gasified fuel. In this paper, the effect of nitrogen injected directly into the combustor on the thermal efficiency of the plant is discussed. A gas turbine combustor with a swirling nitrogen injection function designed with stable and low NOx combustion technology was constructed and the performance of this combustor was evaluated under atmospheric pressure conditions and operational conditions. Main results obtained are as follows:(1) Analyses confirmed that the thermal efficiency of the plant improved by 0.3 percent (absolute), compared with a case where nitrogen is premixed with coal gasified fuel before injection into the combustor.(2) Based on the fundamental combustion tests using the small diffusion burner, we have throught out the new combustion technique which injects nitrogen directly into the high temperature region in the combustor for low NOx and stable combustion.(3) From the combustion tests of the designed and constructed combustor, this new combustion technique with nitrogen direct injection results in a significant reduction in NOx production from nitrogen fixation, 8ppm or less(corrected at 16% O2) in the gas turbine operational conditions for IGCC. CO emission concentration decreased to a significant level, as low as 10ppm, under the operational conditions, or combustion efficiency was almost always 100%. This combustor has an excellenct performance under the operational conditions in IGCC, and bright prospects of low NOx and stable combustion technology of the medium caloric fuel are obtained.

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