煤基化学链燃烧过程中硫的演变

Sulfur Evolution in Chemical Looping Combustion of Coal

在双阶段流化床反应器内,基于溶胶凝胶法制备的Fe2O3/Al2O3氧载体研究了褐煤化学链燃烧过程中燃料硫的迁移路径及分布特性,并讨论了温度、过氧系数对燃料硫释放分布的影响.结果表明:所有工况下,氧载体均未出现被硫化的现象;在热解气化学链燃烧阶段,气相含硫物质以SO2和H2S为主,煤焦气化气化学链燃烧阶段绝大部分为SO2气体,部分来源于煤焦中CaSO4的分解。另外,部分燃料硫被碱金属固定于煤灰中。同时,提高温度和过氧系数都能导致SO2/H2S值和SO2释放量增大。

The migration path and distribution characteristics of sulfur in chemical looping combustion of lignite was investigated in a tailor-made two-stage fluidized bed reactor using the sol-gel prepared Fe2 O3/Al2 O3 as oxygen carrier.The effects of temperature and oxygen to fuel ratio on the sulfur distribution were evaluated in this work.There was no sulfate examined on the used oxygen carrier at all experiments.The SO2 and H2 S were the main sulfurous gases within the chemical looping combustion of volatile.While,SO2 was the dominating sulfurous gas during the chemical looping combustion of char gasification products,which was partly derived from the decomposition of CaSO4 in ash.A part of the sulfur in coal can be fixed in coal ash as sulfate by the alkali metal.Moreover,the ratio of SO2 to H2 S and the release amount of SO2 will be promoted at higher temperature and oxygen to fuel ratio.