Inhibition of steam gasification of biomass char by hydrogen and tar
Inhibition of steam gasification of biomass char by hydrogen and tar
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DOI：
10.1016/j.biombioe.2010.08.017
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发表时间：
2011-01-01
影响因子：
6
通讯作者：
Tsutsumi, Atsushi
中科院分区：
文献类型：
--
作者：
Fushimi, Chihiro;Wada, Tomoko;Tsutsumi, Atsushi
在快速加热热平衡反应器中，研究了不同浓度的氢和焦油对木质生物质焦气化反应速率的影响。研究发现，生物质炭的蒸汽气化过程可分为两个阶段。与第一阶段相比，第二阶段（剩余焦炭相对质量小于0.4）的气化速率有所提高。这些影响可能是由于钾催化剂的内在作用。较高的氢分压在第一和第二阶段极大地抑制了生物质炭的气化。通过计算第一期和第二期炭气化的一级速率常数，我们发现氢对生物质炭气化的抑制作用是由第一期的逆氧交换反应引起的。在第二阶段，碳上的解离氢吸附是主要的抑制反应。左旋葡聚糖（一种从纤维素中提取的主要焦油成分）的影响也进行了研究。结果表明，除氢外，气相左旋葡聚糖及其热解产物均能抑制木质生物质炭的水蒸气气化。当左旋葡聚糖与木质生物质混合后，炭的热解速度略快于木质生物质，水蒸气气化过程中H(2)和CO(2)的析出速率较大。(C) 2010 Elsevier Ltd.版权所有。
The influence of hydrogen and tar on the reaction rate of woody biomass char in steam gasification was investigated by varying the concentrations in a rapid-heating thermobalance reactor. It was observed that the steam gasification of biomass char can be separated into two periods. Compared with the first period, in the second period (in which the relative mass of remaining char is smaller than 0.4) the gasification rate is increased. These effects are probably due to inherent potassium catalyst. Higher hydrogen partial pressure greatly inhibits the gasification of biomass char in the first and second periods. By calculating the first-order rate constants of char gasification in the first and second periods, we found that the hydrogen inhibition on biomass char gasification is caused by the reverse oxygen exchange reaction in the first period. In the second period, dissociative hydrogen adsorption on the char is the major inhibition reaction. The influence of levoglucosan, a major tar component derived from cellulose, was also examined. We found that not only hydrogen but also vapor-phase levoglucosan and its pyrolysates inhibited the steam gasification of woody biomass char. By mixing levoglucosan with woody biomass sample, the pyrolysis of char proceeds slightly more rapidly than with woody biomass alone, and gas evolution rates of H(2) and CO(2) are larger in steam gasification. (C) 2010 Elsevier Ltd. All rights reserved.