The Studies Characteristics Of Methane/Wet Air Autothermal Catalytic Reforming Reaction And Carbon Deposition Under The Low-Temperature

In recent years, micro-engine, which can produce about 10-100W power but only in size around 1cm3, has been aroused widespread concern around the world. How to ensure the fuel highly efficient and stable combustion in the micro-combustion space has become a hotspot of current research. In this thesis, basing on the combustion technology of catalytic reforming of hydrocarbon fuel could improve the micro-combustion, applied the numerical simulation method analyzed methane reforming reaction characteristic in micro-channel. Focus on factors such as the reaction gas composition, reaction wall heat flux, wall temperature and mass flow rate effected on the CH4/O2 autothermal reforming reaction, CH4/H2O reforming reaction and CH4/H2O/CO2 reforming reaction. The carbon deposition characteristics of methane autothermal reforming reaction on the wall were investigated. Results show that:In micro-reactor, the H2 content, CO content, conversion rate of CH4 generated H2 and conversion rate of CH4 generated CO increased along the increase of CH4/O2 mass ratio at first and then decreased. The CO2 content, conversion rate of CH4 generated H2Oand conversion rate of CH4 generated CO2 decreased along the increase of CH4/O2 mass ratio at first and then increased. The CH4 conversion rate sustained increased. The CH4/H2O reforming reaction products CO content increased with the H2O content increased. When the water-carbon ratio is higher than 2.5, the reforming reaction had no significant effect with the water-carbon ratio increasing. In CH4/H2O/CO2 reforming reaction, increased content of CO2 and H2O could expedite the reforming reaction speed.The CH4/O2 autothermal reforming reaction received more energy with the heat flux increased. It could accelerate the reaction speed. The H2 content and CO content increased with the heat flux increased, but the CH4 content, H2O content, CO2 content decreased。In the cold zone, the impact of temperature on the reaction is more significant. When the temperature is above 1300K, a higher temperature has no significant effect on the reaction. When the wall temperature is 900K, the main products of the CH4/CO2 reaction are CO and H2O. While it is 1200K, the main products are CO and H2.The gas residence time and the chemical reaction time micro-reactor are in the same order of magnitude. The residence time dominated by the mass flow rate has a direct impact on the characteristics of catalytic reforming reaction. The smaller mass flow rate, the longer gas residence time is, which strengthened the reaction. The larger mass flow rate, the smaller gas residence time is, and the opposite rule happens.The energy of oxidation reaction released is strengthened with a larger mass ratio of CH4/O2 and the stronger heat flux provides more energy to the reaction system and the smaller mass flow rate increases the reaction time, which increase the carbon deposition on the wall. The carbon deposition on the wall choosing in this thesis is in 10-8mol/m2 order of magnitude. The carbon deposition effect was not obvious.