Investigation Of Contaminants Emission And Heat Transfer Characteristic Of Catalytic Combustion In Ceramic Prous Monolith Of Natural GAS Burner

Recently, people pay more and more attention to ceramic porous monolith infrared burner. The catalytic natural gas combustor of the porous ceramic monolith not only transfers heat by infrared radiation, but also improve combustion efficiency and reduces combustion temperature and the harmful emissions such as HC, CO and NOx etc. This thesis investigates experimentally how the composition of the catalyst and excess air coefficient and thermal load and pore number density of the ceramic monolith influence the emissions. The characteristics of heat transfer of catalytic supports were studied under the condition of the different excess air coefficient and the different compositions of the catalyst. We know from the mechanism of catalytic combustion and contaminants production and its influencing factors, catalytic combustion expedites the reaction rate by reducing the activation energy. The composition of the catalyst and excess air coefficient and combustion temperature and thermal load influence the CH, CO and NOx emissions. According to our experimental results , when air coefficient is between 0.9 and 1.15, carrier 1(Catalyst compositions are Pd2.1‰La3.33‰Ce38.83375‰Ba8.448‰Al2O311%.) is the best for controlling CH production, and whenα=1.02, nothing is emitted and it is better than the non catalyst support. Catalyst does not show any ability of controlling CO emission and its CO emission is even higher than the carrier without catalyst. Carrier 2(Catalyst compositions are Pd2.2‰La3.2376‰Ce37.677‰Ba8.1966‰Al2O311%.) showed a better ability for controlling NOx emission, and when excess air coefficientαreaches1.02, NOx emission is only 7ppm and 5ppm lower than that non-catalyst carrier. Furthermore, NOx emission decreases excess air coefficient. Thermal load can also control the production of combustion contaminants to some extent. CH and CO emissions decrease with thermal load NOx emission increases with thermal load. CO emission decreases and NOx increases with temperature. But the variation rates with temperature are different for different carriers. The largest is the carrier 1. The pore number density of ceramic porous...