Combustion steam reformer design

Traditionally, the steam reforming reactor has a tubular design in which vertical tubes, loaded with catalyst, are surrounded by furnaces to supply the heat required for the strongly endothermic process, see Fig. 8.2. Combustion of natural gas supplies the heat to the tubes. 

High Efficiency Reformer Design. Maximum feedstock and combustion air preheat is used to balance steam generation with steam requirements. 

Autothermal reforming combines partial oxidation and adiabatic steam reforming for conversion of the hydrocarbon feedstock into synthesis gas free of soot and higher hydrocarbons. The ATR reactor design consists of burner, combustion chamber, and catalyst bed placed in a refractory lined vessel, as illustrated in Fig. 10. The hydrocarbon feedstock with steam is reacted with oxygen in a substoichiometric flame, often... 

Residual methane is present at the exit of the combustion zone. In the catalytic bed, the methane steam-reforming and the water shift reactions take place. The gas leaving the ATR reactor is in chemical equilibrium. Normally, the exit temperature is above 900-1100°C. The catalyst must withstand very severe conditions when exposed to very high temperatures and steam partial pressures. One example of an ATR catalyst is nickel supported by magnesium aluminum spinel. For compact design, the catalyst size and shape is optimized for a low pressure drop and high activity. 

The probabilistic safety assessment (PSA) for the steam reforming process was carried out to investigate the cause of an accident on combustible gas leak and a conceptual design on a countermeasure against explosion was carried out aiming at reducing the probability ofthe combustible gas leak less than 10-6/year. The rupture of combustible gas pipes is considered as the cause of the leakage. 

Yoshida et al. [173] designed an integrated methanol fuel processor from silicon and Pyrex glass substrates for a power equivalent of 10 W. It contained functional layers for steam reforming, evaporation, and combustion. Commercial Cu/ ZnO catalyst served for reforming and the Pt/TiOa combustion catalyst was prepared by a sol-gel method. A power density of 2.1 W/cm was determined for the device. 

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