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Development of Removal Method of Fuel Nitrogen as N_2

N_2燃料氮脱除方法的研制

基本信息

批准号：
05558072
负责人：
OHTSUKA Yasuo
金额：
$ 5.63万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05558072/
关键词：
Fuel Nitrogen Coal Nitrogen Removal Fine Iron Catalyst

项目摘要

1.About 50 - 60 % of fuel nitrogen in coal can successfully be removed as N_2 when coal with the finely dispersed iron catalyst is simply pyrolyzed in an inert atmosphere. The amounts of NH_3 and HCN evolved are decreased by catalyst addition, and the residual nitrogen in the char is also decreased remarkably. Expensive H_2 is unnecessary for the present nitrogen removal. Heat treatment of a nitrogen enriched carbon shows that fine iron particles promote solid phase removal reactions of fuel nitrogen.2.The chlorine-free, highly-dispersed iron can be prepared from inexpensive FeCl_3 by the precipitation method using Ca(OH)_2. The iron on coal exists as fine FeOOH particles, which are reduced to iron metal and carbide with the size of 20 - 50 nm during coal pyrolysis. Such fine particles and/or the clusters promote the nitrogen removal of coal.3.The yields of oil and tar evolved are unchanged by iron addition, but the nitrogen contents are decreased. The presence of the iron leads to a lower amount of volatile nitrogen and a higher amount of N_2, showing the conversion to N_2 by secondary decomposition reactions of volatile nitrogen over the catalyst. The experiments using pure N-containing compounds verify that the finely-dispersed iron can promote the decomposition of pyrrol considerably.4.The atomic ratio of H/C is lower in the iron-bearing char than in the original char, and the degree of carbon crytallinity is higher in the former. The carbon crystallization and decreased catalyst dispersion by pyrolysis lower not only the reactivity of char in steam but the rate enhancement by the iron. The functionality analysis of char nitrogen shows that pyrrolic nitrogen is converted to N_2 more selectively with the catalyst. Fuel nitrogen can be removed mostly as N_2 during the iron-catalyzed CO_2 gasification of coal.

1.在惰性气氛下，煤中约50 ~ 60%的燃料氮可被成功地脱除为N_2。添加催化剂后，NH_3和HCN的生成量明显减少，残氮量也明显降低。目前的脱氮工艺不需要昂贵的氢气。富氮炭的热处理表明，细小的铁颗粒促进了燃料氮的固相脱除反应。2.以廉价的FeCl_3为原料，采用Ca（OH）_2沉淀法制备无氯、高分散的铁。煤中的铁以FeOOH微粒的形式存在，在热解过程中，FeOOH被还原为20 ~ 50 nm的金属铁和碳化物。铁的加入对煤的脱氮有促进作用。3.添加铁后，煤的热解油和焦油产率基本不变，但氮含量降低。铁的存在导致挥发性氮的量减少而N_2的量增加，表明挥发性氮在催化剂上通过二次分解反应转化为N_2。实验结果表明，铁的细分散对吡咯的分解有明显的促进作用。4.含铁半焦的H/C原子比比低于原始半焦，碳的结晶度高于原始半焦。热解过程中碳的结晶和催化剂分散度的降低不仅降低了半焦在水蒸汽中的反应活性，而且降低了铁对反应速率的促进作用。焦炭氮的官能度分析表明，该催化剂能更好地将吡咯氮转化为N_2。在铁催化CO_2气化过程中，燃料氮主要以N_2的形式脱除。