報告書番号

W17

タイトル（和文）

ガス化燃料用ガスタービン燃焼器の開発

タイトル（英文）

Development of Gas Turbine Combustor for the Gasified Fuels

概要 （図表や脚注は「報告書全文」に掲載しております）

次世代火力発電方式として各種ガス化複合発電(IGCC)の開発・実証が国内外で進められている。ガス化燃料は主にガス化炉で用いられるガス化剤(空気、酸素)およびガス精製方式(乾式、湿式)により特徴付けられ、４種類に大別される。すなわち、ガス化剤が空気の場合は約4MJ/m3の低カロリー燃料となり、燃焼安定性が問題となる。一方、ガス化剤に酸素を用いた場合には発熱量が9～13MJ/m3の中カロリー燃料となり、火炎温度がLNGよりも高くなるためサーマルNOxの抑制が課題となる。また、熱効率向上を目的にガス精製に乾式法を採用した場合、ガス化燃料中にアンモニアが含まれフュエルNOxが多量に発生する。このため、各種IGCC方式に応じたガスタービン燃焼器の開発課題が生じる。本研究では、これら４方式によるガス化燃料について、小型拡散バーナを用いた燃焼実験と反応動力学数値解析により燃焼特性を把握し、低NOx燃焼技術を提案する。さらに、ガスタービン燃焼器を設計、試作し、模擬燃料を用いた燃焼実験により燃焼器性能を確認することにより、各種IGCC方式に対応できるガスタービン低NOx燃焼器技術を確立した。また、より一層の環境保全性向上を目的に、ガス化燃料中に含まれるNH3を乾式で約40％まで分解除去する手法を開発した。

概要 （英文）

Development of the integrated gasification combined cycle (IGCC) power generation of various gasifying methods has been preceded in the world for near future thermal power plant.The gasified fuel is chiefly characterized by the gasifying agent and the synthetic gas clean-up method, and divided roughly into four types. That is, the calorific value of gasified fuel differs according to the type of gasification agent used in the gasifier. If the gasification agent is air, then gasified fuel forms a low calorific fuel of 4MJ/m3, which is about one-tenth of LNG. The flame temperature is low because gasified fuel contains about 70 percent nitrogen different from LNG, and it is necessary to stabilize the flame of low calorific fuel. On the other hand, if the agent is oxygen, then the gasified fuel becomes a medium calorific fuel between approximately 9-13 MJ/m3, the flame temperature is higher than that of LNG, and so NOx production from nitrogen fixation in air is expected to increase. It is necessary to control the thermal NOx emissions. Moreover, to improve the thermal efficiency of IGCC, it is necessary to use a hot/dry type synthetic gas clean-up system, but ammonia (NH3) originated from nitrogenous compounds in coal in the gasifier is not removed. This NH3 is then fed into the gas turbine where it forms fuel-NOx in the combustion process. For these reasons, the combustion technology for each gasified fuel and the ammonia removal technique from gasified coal fuels are important. In this paper, I clarified the combustion characteristic of these four types of gasified fuels through experiments using a small diffusion burner and through numerical analysis based on reaction kinetics. I propose the low-NOx combustion technology for each gasified fuel, design the gas turbine combustors, and verified the combustor performances by the combustion tests using the simulated gasified fuels. Also, aimed at the more efficient and environmentally sound options in IGCC with the hot/dry type synthetic gas clean-up, I propose an ammonia removal technique from gasified coal fuel in a dry method and verify the effects through experiments using a tubular flow reactor and reaction kinetic analyses. The method was effective in decreasing total fixed nitrogen that remains in the fuel without being removed by up to 40%.

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