Experimental investigation of tri-reforming on a stationary, recuperative TCR-reformer applied to an oxy-fuel combustion of natural gas, using a Ni-catalyst

Abstract

Experimental investigations into stationary thermochemical recuperation are presented with three modifications compared to current researches: (I) A recuperative reformer was used. Current waste heat regeneration concepts use regenerative heat exchangers, which have numerous disadvantages: size, leakage and unsteady operation. In contrast, recuperative reformers enable the possibility of compact design and allow stationary operation. (II) The energy available for the reforming process was provided with the thermal energy of exhaust gases. (III) Oxygen was added to the reforming reaction. In the experiments, exhaust gases were used as reactants. The reactants are thus characterized by a fixed molar ratio of H2O/CO2=2/1 causing a maximum steam-to-carbon-ratio of 0.5. Steam-to-carbon-ratios of this size favour coke formation. The addition of oxygen to the reactants caused partial oxidation of methane which additionally released steam and increased the reaction temperature. Coke formation was thus inhibited.The influence of oxygen on the CH4-conversion and on the formation of carbon was determined. A maximum CH4-conversion-rate of 89.85% was achieved by adding oxygen without the formation of carbon deposits. Moreover, temperature measurements inside the reactor were performed. The addition of oxygen influenced the reaction temperature due to partial oxidation of methane resulting in a temperature increase of more than 100∘C.