(575u) Catalytic Combustion of Psa Residue Gas In Hydrogen Station Over Hexaaluminate Catalysts
Combustion system is widely used in home, transport and plant etc.. In principle, Products of hydrocarbon oxidation are carbon dioxide and water. However, unburned hydrocarbon, carbon monoxide, soot and NOx are founded in exhausted gas of conventional flame combustion. It is not energy-efficient and environmental-friendly. As an alternative of flame combustion, catalytic combustion has been extensively researched for decades due to its attractive traits. First of all, catalyst's ability to decrease activation energy makes it operate at lower temperature than conventional combustion, so it generates less thermal NOx which is strictly regulated for environmental aspects. Second, in wide range of air-to-fuel ratio catalytic combustion makes possible complete oxidation of fuel. For commercial development, two major problems have to be solved. Catalyst has catalytic activity for fuels and has thermal stability. In respect to activity, noble metal, like Pd and Pt, was widely used. A noble metal has distinguished catalytic activity compared to metal oxide. However, Noble metals are thermally unstable; easily aggregated and volatile at high temperature. For these reason, there are an effort for finding thermally stable and active catalyst. Arai and Machida first proposed the hexaaluminate as catalytic materials in the high temperature catalytic combustion. Hexaaluminate phase is made at over 1200°C and retains surface area about 10 m2/g. In hydrogen station needs burner to supply heat to main reformer and several processes. To operate the stations efficiently, the normal flame burner replaced by catalytic combustion and PSA residue gas is used as a fuel. The objective of this study is to make a thermally stable hexaaluminate catalyst and apply it to PSA reside gas condition.