UTILIZATION OF METHANE AND CARBON DIOXIDE TO PRODUCE HYDROGEN-RICH STREAM

Abstract

In this research, the hydrogen production of dry reforming reaction via utilization of methane and carbon dioxide was studied. The dry reforming reaction has the advantage of reducing greenhouse gases. Other advantages are the recycle of hydrocarbons from the atmosphere to produce energy source as hydrogen, and reduce a releasing of hydrocarbons from earth drilling for fossil fuel in order to keep global warming crisis less severe than the present. Carbon monoxide from the reforming reaction will be eliminated by water gas shift reaction, preferential oxidation and carbon monoxide adsorption by water in order to reduce a carbon monoxide level. To get the maximum performance, experimental design and analysis of variance will be used to investigate significant factors; moreover, the optimum condition will be found. In the dry reforming reaction, 5%Ni-0.5%Mn/CeO2 catalysts was tested to find the suitable condition including temperature of 820 °C, the methane fraction of 0.5, 0.1 g of catalysts weight and 30 ml/min of total feed rate given CH4 conversion, CO2 conversion and H2 selectivity of 70%, 60% and 60%, respectively. The water gas shift reaction, the 1%(1:1)AuFe/CeO2 catalyst was selected to study for experimental design. Significant factors are controlled an appropriate range of temperature 413 °C, catalyst weight of 0.2 g and water feed rate of 2 ml/h, presenting CO conversion and H2 yield were 70% and 50%, respectively. The preferential oxidation reaction, the 1%Au/CeO2 catalyst was investigated an optimum condition that give 90 °C, O2/CO ratio of 1.5, and no amount of carbon dioxide in the feed stream. It gave a yield of the reaction around 52%. Integration process (DRM, WGS and PROX) can reduce the amount of carbon monoxide level into satisfactory range, but hydrogen composition is less. Thus, double stage of the water gas shift was performed to improve the performance, which gives that CO conversion and H2 conversion increased to 90% and 75%, respectively. Then the outlet gas passed through water trap to further remove carbon monoxide. A small amount of carbon monoxide can be dissolved in water because some of its behavior similar to carbon dioxide. This research work, finally showed outlet gas component consisted of 30% H2, 60% He, and 10% others with total flow rate around 90 ml/min.