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Autothermic Reforming by Super-Adiacatic Combustion in Porous Media

多孔介质中超绝热燃烧的自热重整

基本信息

批准号：
11650216
负责人：
HANAMURA Katsunori
金额：
$ 2.24万
依托单位：
Gifu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650216/
关键词：
Porous Medium Reforming Super-Adiabatic Combustion Hydrogen Energy Conversion

项目摘要

Autothermic reforming by super-adiabatic combustion in porous medium was investigated through numerical simulation and experiment. A mixture of methane, air and steam is introduced into a spongelike porous medium, where the flow direction is alternated at a regular interval. Both gas-phase combustion and reforming reaction occur around the middle of the porous medium which is made of a cordierite ceramics with a nickel catalyst layer for the reforming reaction. During the period when the product gases pass through the porous medium, the flowing gas enthalpy is stored by the porous medium. Upon reversal, the mixture is preheated before entering the reaction zone, as flowing through the porous medium. By using the reciprocating-flow system, the excess enthalpy combustion occurs ; as a result, the flammability limit is extended to the fuelrich side. Consequently, a part of the methane supplied is consumed for exothermic reaction, i.e., combustion reaction with oxygen, while the residual p … More art is converted into the hydrogen ; where the endothermic reaction for the production of hydrogen occurs.For the reciprocating-flow super-adiabatic combustion system, the flammability limit is extended to the equivalence ratio of about 5 by the heat recirculation. The most striking feature is that the methane conversion, i.e., the conversion ratio from methane to hydrogen, reaches the value above 90 % over a wide range of the equivalence ratio, and the exit temperature of the product gas is almost the same as that of the inlet temperalure. That is, the combustion reaction heat is effectively converted into the reaction heat for the production of hydrogen, and the flowing gas enthalpy is effectively recirculated to increase the temperature of the mixture. With increasing equivalence ratio, the methane conversion decreases because of the decrease in the temperature in the porous catalyst. In this case, to avoid the deposition of the carbon on the catalyst surface, the large amount of steam is supplied. For the ratio of the steam flow rate to the methane flow rate of 7, the mass of carbon is conserved within 5% between the inlet and outlet of the reformer. Furthermore, the reforming system proposed here has a much higher space velocity of 2600(/h)than that of 500(/h)for conventional tubular reformers. Consequently, the reforming system proposed here has a high potential to reduce the scale of the reformer and to produce some valuable species through the combustion process. Less

对多孔介质中超绝热燃烧自热重整进行了数值模拟和实验研究。将甲烷、空气和蒸汽的混合物引入海绵状多孔介质中，其中流动方向以规则的间隔交替。气相燃烧和重整反应都发生在多孔介质的中部周围，该多孔介质由堇青石陶瓷制成，具有用于重整反应的镍催化剂层。在产品气体通过多孔介质期间，多孔介质存储流动气体焓。在反向时，混合物在进入反应区之前被预热，因为流动通过多孔介质。通过使用往复流系统，发生过量焓燃烧;结果，可燃极限扩展到富燃料侧。因此，供应的甲烷的一部分被消耗用于放热反应，即，燃烧反应与氧气，而剩余的p ...更多信息对于往复流超绝热燃烧系统，通过热再循环，可燃极限扩展到约5的当量比。最显著的特征是甲烷转化率，即，在较宽的当量比范围内，甲烷转化为氢气的转化率达到90%以上，产品气的出口温度与入口温度几乎相同。即，燃烧反应热被有效地转换成用于产生氢的反应热，并且流动的气体焓被有效地再循环以升高混合物的温度。随着当量比的增加，由于多孔催化剂中的温度降低，甲烷转化率降低。在这种情况下，为了避免碳在催化剂表面上的沉积，供给大量的蒸汽。对于蒸汽流速与甲烷流速的比率为7，在重整器的入口和出口之间，碳的质量保持在5%以内。此外，本文提出的重整系统具有比常规管式重整器的500（/h）高得多的2600（/h）的空速。因此，这里提出的重整系统具有很高的潜力，以减少重整器的规模，并通过燃烧过程产生一些有价值的物种。少