化学链燃烧中钙基载氧体CaSO_4再生的氧化反应机理  

Oxidation of CaS with O_2 for oxygen carrier regeneration in chemical-looping combustion

作　　者：郑敏[1] 沈来宏[1] 高正平[1] 肖军[1] 

机构地区：[1]东南大学热能工程研究所,南京210096

出　　处：《环境科学学报》2009年第2期330-338,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金项目(No.90610016);国家重点基础研究发展计划(973)项目(No.2006CB20030201;2006CB705806);国家高技术研究发展计划(863)项目(No.2006AA05Z318)~~

摘　　要：在热重和红外联用进行等温实验的基础上,探讨了氧体积分数为10%、20%,970～1150℃温度范围内化学链燃烧过程中钙基载氧体再生(CaS)的氧化特性.结果显示,CaS氧化的直接产物主要为CaSO4,只有在诱导期生成极少量CaO和SO2;但CaSO4与CaS还可进一步反应,生成更多CaO和SO2.通过对氧气浓度和温度的实验条件改变,研究了CaSO4的转化率、转化速率,并辅以SO2析出速率分析,获得了CaSO4相对于CaO的瞬时选择性、CaSO4的收率和反应选择率.结果表明,钙基载氧体CaSO4再生过程氧化反应的适宜条件为温度970～1000℃以及较高的氧气气氛,这不仅可以抑制SO2的排放量从而得到较高的反应选择率,同时反应过程也具有较高的转化速率.Oxygen carrier regeneration by CaS oxidation at different oxygen concentrations （ 10% and 20% ） and at different temperatures （ from 950℃ to 1150℃ ） was studied based on isothermal tests with thermogravimetric analysis （TGA） and Fourier Transform Infrared （FT-IR） spectroscopy. The results revealed that CaS was oxidized to CaSO4 directly, with a small amount of CaO and SO2 being formed during the induction period. However, the product CaSO4 further reacted with the reactant CaS via a solid-solid reaction to form more CaO and SO2. The influences of oxygen concentration and temperature on the conversion ratio and the conversion rate of CaSO4 are discussed. From the SO2 evolution rate, the transient selectivity of CaSO4 for CaS oxidation was also obtained, along with the CaSO4 yield and the selectivity of regeneration reaction. The optimum conditions are as follows ： the air reactor should be between 970℃ and 1000℃ and at a high oxygen concentration to prevent SO2 emission. Thus, improved selectivity of the CaSO4 regeneration reaction and a relatively high reaction rate could be obtained.

关 键 词：CO2分离 化学链燃烧 CaSO4载氧体 载氧体再生 CaS氧化 

分 类 号：X706[环境科学与工程—环境工程]