報告書番号

W98029

タイトル（和文）

石炭の加圧燃焼における窒素化合物および粒子状物質の生成特性 -850ﾟCの微粉炭燃焼における圧力の影響-

タイトル（英文）

The behavior of nitrogen compounds and particle matter in the pressurized coal combustion

概要 （図表や脚注は「報告書全文」に掲載しております）

微粉炭燃焼場における石炭の燃焼性および窒素化合物や粒子状物質の生成挙動に及ぼす圧力の影響を常圧および加圧の電気加熱式管状反応炉（ＤＴＦ）を用いて明らかにした。加圧燃焼試験は、圧力：0.1-2.1MPa、温度:850ﾟC、空気比：1.2の条件で、ニュ－ランズ炭により行い以下の結果を得た。(1)加圧により燃焼性が増大し、常圧で85％の燃焼率が0.6MPaで95％以上に達した。(2)石炭中ＮのNO､N2O､HCNへの変換率は、加圧により減少し、0.6MPaで3％程度（常圧時の約1/3）であった。この条件で石炭中Ｎはほとんど気相中に放出されたが、その形態はN2と推定された。(3)生成粒子形状は、0.6MPa以上で燃焼初期から微小粒子を含む溶融生成灰の集合体が多く観察された。(4)本実験結果に基づく伝熱計算から、2.1MPaの燃焼における粒子温度は1500ﾟC以上になると推定された。

概要 （英文）

Pulverized coal combustion characteristics in elevated pressure was investigated with atmospheric and pressurized drop-tube furnace (A-,P-DTF) . Especially the effects of pressure and residence time on the formation of nitrogen compounds and characteristics of particle matter from coal were studied. The experiments with DTF were carried out under the following conditions: gas temperature 1123 K, pressure 0.1 - 2.1 MPa, air ratio 1.2, residence times 0.25-6 s. Combustion rate was determined by weight loss of burning coal particle and analysis of product gas. The results were as follows: (1) At high pressure condition the combustion rate increased and combustion efficiency was above 95% in 0.6MPa. (2) The conversion ratio from coal-N (nitrogen contained in coal) to NO, N2O and HCN decreased to 3% in 0.6MPa as pressure increased. This ratio corresponded to the one-third of that in atmospheric combustion. In this condition the most of coal-N was released to gaseous phase and this compound was estimated to be N2. (3) From the beginning of combustion at pressure above 0.6MPa, the aggregated particles of small molten ash were observed. (4) It was estimated that a temperature of the particle produced in combustion of 2.1MPa was above 1500ﾟC by the heat calculation on the basis of experimental results.

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