微细腔内甲烷湿空气预混催化重整产氢特性

Characteristics of Generating Hydrogen from Methane-Wet Air Catalytic Reforming Reaction in the Microcombustor

针对微动力机电系统易熄火,燃烧效率不高等问题,体力学软件FLUENT6.2和可以计算表面反应的化学反应动力学软件CHEMKIN4.0,对甲烷/湿空气在壁面涂有含稀土的镍基催化剂的微细预混腔中催化重整产氢特性进行了数利用碳氢燃料和湿空气中水蒸气预混催化重整产氢来强化燃烧,以实现微尺度下燃料的持续稳定高效燃烧。针对提出的微细燃烧动力装置内燃料-空气预混腔,联合使用计算流值研究,探讨了微细腔中甲烷蒸汽重整的关键影响因素。结果表明:在微细预混腔内甲烷湿空气预混催化重整中,水碳比、催化壁面温度和混合气质量流量对重整产氢性能有重要的影响。在微细腔内,水碳比为1、温度高于1100K和满足一定发电量情况下相对低的质量流量有利于高产氢量、高重整效率和相对低的水蒸气残余量。在催化壁面温度恒定为1100K、水碳比为1、甲烷的质量流量为6.5g/h以及甲烷和湿空气的质量流量比为0.2情况下,出口氢气质量浓度可达3.5%。

Aim at problems of the combustion-based power MEMS devices being flameout easy and low efficiency etc, the combustion technology that improved and realized hydrocarbon fuels last, steady-state and high efficiency combustion by generating part of hydrogen from hydrocarbon fuels and stream catalytic reforming reaction are presented. In this paper, characteristics of generating hydrogen from methane wet air catalytic reforming reaction on the premixed chamber wall with Ni katalyst was done with numerical simulation, using both CFD FLUENT and surface chemistry subroutine CHEMKIN for the microscale combustor premixed chamber the author proposed. In addition, the key factors that influence stream reforming of methane in micro-scale were discussed. Results indicate that stream/methane mole ratio, catalytic wall temperature and mass flowrate of premixed gases have more influence on characteristics of generating hydrogen. In micro-scale, stream/methane mole around 1, catalytic wall temperature above llooK and flowrate relative lower in the condition of meeting the power generation rate are beneficial to achieve high production of hydrogen, high reforming efficiency and lower steam remains, and data displays that hydrogen concentrations can be up to 3.5% while the stream/methane mole ratio, catalytic wall temperature, flowrate and methane/air mass flowrate ratio are 1, 1100K, 6.5g/h and 0.2 respectively.