Analysis of reaction mechanism and kinetics of biomass in pyrolysis and gasification

生物质热解气化反应机理及动力学分析

基本信息

批准号：
20760520
负责人：
FUSHIMI Chihiro
金额：
$ 2.75万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Young Scientists (B)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2009
项目状态：
已结题

项目摘要

Biomass gasification is a promising technology because of the high thermal efficiency. However, a large amount of condensable organic compounds (tar) which causes blockages and corrosion of pipes are evolved in biomass gasification.In this study, the inhibition of the gasification rate of biomass char by H_2 and tar was investigated. At first, the reaction rate of char in steam gasification was measured using a thermobalance reactor by varying partial pressure of H_2 (P_<H2>=0, 3, 10, 25kPa). The rate of steam gasification was decelerated by the presence of H_2 and the inhibition was significant when the partial pressure of H_2 was high (P_<H2>=25kPa). It was found that reverse oxygen exchange occurred at first period and dissociative adsorption of H_2 on char occurred at second period. The effect of levoglucosan, which is major component of pyrolysis product from cellulose, on the reaction rate of char was also measured with a newly developed drop-tube/fixed bed thermobalance reactor. It was found that not only H_2 but also other hydrocarbons evolved by pyrolysis of levoglucosan substantially inhibit char gasification when the feed rate of levoglucosan was high (250mg/min).In addition, the effects of alkali and alkaline earth metals (AAEM), which can act as an excellent catalyst for the gasification and combustion reactions, on the interactions between the three major components of biomass (cellulose, xylan and lignin) were investigated. It is found that AAEM decreased the generation of water-soluble tar derived from cellulose. AAEM do not have significant influence on the interaction between cellulose and xylan.

由于热效率高，生物质气化是一项有前途的技术。但是，在生物质气化中进化了大量可凝结的有机化合物（TAR），这些化合物（TAR）在生物质气化中进化出来。在这项研究中，研究了H_2对生物量CHAR的气化速率的抑制和TAR进行了研究。首先，通过改变H_2的部分压（P_ <h2> = 0、3、10、25KPA），使用热脑反应器测量蒸汽气化中的CHAR反应速率。 H_2的存在会减少蒸汽气化速率，当H_2的二压较高时，抑制作用很明显（P_ <h2> = 25KPa）。发现在第一阶段发生了反氧交换，并且在第二阶段发生了H_2的解离吸附。还用新开发的Drop-Tube/固定床热能反应器测量了Levoglucosan（是纤维素中的主要成分）对CHAR反应速率的主要成分。 It was found that not only H_2 but also other hydrocarbons evolved by pyrolysis of levoglucosan substantially inhibit char gasification when the feed rate of levoglucosan was high (250mg/min).In addition, the effects of alkali and alkaline earth metals (AAEM), which can act as an excellent catalyst for the gasification and combustion reactions, on the interactions between the three major研究了生物量（纤维素，Xylan和木质素）的成分。发现AAEM降低了源自纤维素的水溶性焦油的产生。 AAEM对纤维素和Xylan之间的相互作用没有显着影响。