Selective and complete catalytic oxidation of natural gas in Turbulent Fluidized Beds

Abstract

Turbulent Fluidized Bed (TFB) reactors appears to be ideal for exothermic and fast reactions such as catalytic oxidation of methane. In this paper, a use of TFB reactor for two catalytic oxidation of methane: catalytic combustion of methane and catalytic selective oxidation of methane for the ethylene synthesis is described. Catalytic fluidized bed combustion of methane is shown to be an emerging technology capable of meeting all environmental constraints as far as nitrogen oxides and carbon monoxide are concerned. This reaction carried out in both the bubbling and the turbulent regimes at 450-500 ‡C shows that the turbulent regime is more favourable. A self-sustained combustion with complete conversion and a zero emission of NOx and CO was achieved with a mixture of 4% methane in air at 500 ‡C. The two-phase model of Werther [1990], which phenomenologically introduces the enhancement factor due to chemical reaction, predicts quite well the combustor performance. The same model but without enhancement factor (slower reactions) predicts satisfactorily the experimental data for the oxidative coupling of methane and can be used to quantify the influence of homogeneous and catalytic reactions.