Analysis of reformer furnace tubes for hydrogen production using radiative zonal model

•A new application of our previous 3-D radiation zonal method.•Practical effect of tube diameter to reduce fuel consumption.•Change of dimensions based on the standard design procedures.•Useful design analysis to help a designer to know about radiation phenomena.•Employing three standards to get a conclusion from the analysis.

Reformer tubes are commonly used in furnaces to produce hydrogen and synthesis gas in the refining, petrochemical and fertilizer industries. An optimum arrangement and dimensions of the reformer tubes could be obtained from a mathematical modeling. In the present study, a comparison of different tube sizes is presented based on the well-established radiation zonal analysis in the furnace beside mass, momentum, and energy balance in the reactor tubes. For the practical case studies, three Cr–Ni alloy stainless steel tubes were selected to analyze different tube dimensions including diameter, thickness and tube spacing with the same inlet process feed, fuel consumption and catalyst weight. It is shown that for three industrial tube materials a 20% increase in the tube diameter causes a 20% increase in the tube thickness, 10–20% decrease in furnace length (according to the design procedure) and 3–6% decrease in methane conversion. The results of another analysis show that a 5–9% decrease in the fuel consumption is followed by a 20% decrease in the tube diameter for the same amount of hydrogen production for three cases. Moreover, the three tube materials were compared in accordance to the fuel consumption. In all cases minimum tube thickness is desirable.