Reactor methane steam/burner

Figure 7.1 Schematic diagram of the Haldor Topsoe methane steam reformer/burner reactor [476].

The reformer takes an input flow rate of methane and computes the hydrogen output. The reformer module balances energy by combusting the reformate stream with air and exchanging the heat released to the catalyst reactor. Parameters on the reformer are the steam-to-carbon ratio and the outlet temperature of the exhaust products from the internal burner. The temperature at which the equilibrium reforming occurs depends on these parameters. Figure 1 shows the variation in thermal efficiency of the reformer with temperature and steam-to-carbon ratio. The minimum steam-to-carbon ratio is 2 however, reformers are often operated with excess steam to improve the efficiency and prevent coking problems. 

SIU Naphtha, LPQ, Of Acetylene purity 99.6%. Ethylene. Two types of burner One adapted o i be pyrolysis of methane end completely metallic. Ihe second adapted to Ihe pyrolysis of heavier hydrocarbons, similar to the Eastman reactor. Water (90 C>. Water and oiL 0.I IO 1.2.10 fa absolute. Aqueous ammonia fur CO). Liquid ammonia iJirC) for tvi,- Mcthumd or kerosene ft>f c,. Steam treatment. Distillation. Degassing or steam treatment... 

The reformer is a direct fired chemical reactor consisting of numerous tubes located in a firebox and filled with catalyst. Conversion of hydrocarbon and steam to an equilibrium mixture of hydrogen, carbon oxides and residual methane takes place inside the catalyst tubes. Heat for the highly endothermic reaction is provided by burners in the firebox. The heat is transferred to the catalyst filled reactor tubes by a combination of radiation and convection. 

Kikuchi [111] described a natural gas MR, which had been developed and operated by Tokyo Gas and Mitsubishi Heavy Industries to supply PEM fuel cells with hydrogen. It was composed of a central burner surrounded by a catalyst bed filled with commercial nickel catalyst. Into the catalyst bed 24 supported palladium membrane tubes were inserted. The membranes had been prepared by electroless plating and were 20 pm thick. Steam was used as sweep gas for the permeate. The reactor carried 14.5 kg catalyst. It was operated at 6.2 bar pressure, S/C ratio of 2.4, and 550°C reaction temperature. The conversion of the natural gas was close to 100%, wdiile the equilibrium conversion was only 30% under the operating conditions. The retentate composition was 6 vol.% hydrogen, 1 vol.% carbon monoxide, 91 vol.% carbon dioxide, and 2 vol.% methane. 

A methane or natural gas fuel processor with 2.5-kW thermal energy output was described by Heinzel et al. [17]. It consisted of a pre-reformer, which made future multi-fuel operation possible, the reformer itself, which carried a nickel catalyst [433], it was operated between 750 and 800 ° C, and had catalytic carbon monoxide clean-up. The preferential oxidation reactor was operated at an O/CO ratio of 3.5 [433]. A carbon monoxide content of between 20 and 50 ppm could be achieved during steady state operation. An external burner suppUed the steam reforming reaction with energy. The natural gas was desulfiirised by a fixed bed of impregnated charcoal. Figure 9.21... 

Figure 5.5 shows a typical autothermal reformer with burner and adiabatic catalyst fixed bed in the lower part As in the case of steam reforming with catalyst tubes fired from outside the endothermal methane reaction occurs on a nickel catalyst Due to the lack of heat supply, the gas mixture cools down and reaches almost the value of the methane and water-gas shift equilibrium according to reactions (5.1) and (5.2) at the outlet Typical values for the outlet temperature vary from 900 °C to 1100 °C [5.26] depending on the application. Since the autothermal reformer has to be brick lined similar to the PO-reactor, there is no limitation to pressures of max. 40 bar compared to steam reformers with catalyst tubes. 

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