摘要
采用流化床燃烧技术,使用自制Cu/γ-Al2O3颗粒作为催化剂床料,实验研究了超低浓度甲烷在流化床中催化燃烧时床层温度(450～700℃)、流化风速比ω(1.5～4)、进气甲烷体积分数(0.3%～2%)等对甲烷燃烧效率的影响。结果表明,床层温度是影响甲烷催化燃烧反应的关键因素,甲烷的转化率随着床层温度的升高而增加;床层温度达到650℃时,甲烷含量低于1%的超低浓度甲烷其转化率超过95%,继续提高床层温度至700℃且控制流化风速比ω≤2可以实现甲烷的完全转化;甲烷转化率随着流化风速和进气甲烷浓度的增加而降低,当ω>3.5时,温度对甲烷转化的影响减弱,未燃烧的甲烷含量增大。动力学实验发现,床层温度较低时,催化反应受动力学控制,测得催化反应的活化能Ea为1.26×105J/mol,反应级数m为0.73,当温度t>450℃时,扩散作用影响显著,反应级数增大。
Catalytic combustion of ultra-low content methane was carded out in a fluidized bed reactor with Cu/γ-Al2O3 catalysts as particle bed material; the effects of bed temperature （450- 700 ℃ ）, fluidizing velocity ratio （ω, 1. 5 -4）, and inlet methane concentration （0. 3% -2%） on the combustion characteristics were investigated. The results show that the bed temperature is a major influencing factor for the catalytic combustion; methane conversion increases with the bed temperature. When the bed temperature reaches 650 ℃, methane conversion exceeds 95% with the methane concentration lower than 1% ; methane can be almost completely converted when the bed temperature reaches 700 ℃ and the fluidizing velocity ratio ω is not higher than 2. Methane conversion decreases with the increase of the fluidizing velocity and inlet methane concentration; when ω exceeds 3.5, the influence of temperature on methane conversion becomes less significant with an increase of the unburned methane content. Under a low temperature, the combustion is controlled by the catalytic reaction rate; activation energy Ea and reaction order m estimated by regression are 1. 26 × 105 J/mol and 0. 73, respectively. When the bed temperature exceeds 450 ℃, mass transport limitations turns to an important factor influencing the methane conversion.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2012年第7期886-891,共6页
Journal of Fuel Chemistry and Technology
基金
重庆市自然科学基金(2009BA6067)
中央高校基本科研业务费(CDJZR12140031)
关键词
超低浓度甲烷
流化床
催化燃烧
甲烷转化率
动力学
ultra-low concentration methane
fluidized bed
catalytic combustion
methane conversion
kinetics
