Reforming continued tubes

The pyrolytic reforming reactor was a packed bed in a quartz tube reactor. Quartz was selected to reduce the effect of the reactor construction material on the hydrocarbon decomposition rate. ° The reactor was packed with 5.0 0.1 g of AC (Darco KB-B) or CB (BP2000) carbon-based catalyst. The reactor was heated electrically and operated at 850—950 °C, and the reactants had a residence time of 20—50 s, depending on the fuel. The reactor was tested with propane, natural gas, and gasoline as the fuels. Experiments showed that a flow of 80% hydrogen, with the remainder being methane, was produced for over 180 min of continuous operation.The carbon produced was fine particles that could be blown out... 

The reformer tube operation was simulated on the basis of a set of continuity-, energy- and momentum equations using one and two dimensional heterogeneous models. Intraparticle gradients in the rings were accounted for by the use of the generalized modulus concept. 

Also important is the effect of the size and shape of the catalysts [428] on heat transfer and consequently performance. Unlike the most processes carried out under substantially adiabatic conditions, the endothermic steam reforming reaction in the tubes of the primary reformer has to be supplied continuously with heat as the gas passes through the catalyst. The strong dependency of the reaction rate on the surface temperature of the catalyst clearly underlines the need for efficient heat transfer over the whole length and crosssection of the catalyst. However, the catalyst material itself is a very poor conductor and does not transfer heat to any significant extent. Therefore, the main mechanism of heat transfer from the inner tube wall to the gas is convection, and its efficiency will depend on how well the gas flow is distributed in the catalyst bed. It is thus evident that the geometry of the catalyst particles is important. 

This reaction requires continued external combustion of methane to maintain the red heat (Table 11.3) of the reformer tubes, since this is an endothermic reaction. It produces most of the hydrogen required. 

Tubular membranes and seal assemblies were tested in high-pressure, high-temperature lab-scale units under ITM S mgas and ITM H2 process conditions. In these tests, pre-reformed natural gas mixtures at process pressure were passed over the outer surface of the tubular membrane, while air at atmospheric pressure was fed to the inner surface of the tube. Multiple tests under ITM H2 conditions each operated continuously for over 6 months at 250 psig and 825°C with good performance stability. The results of one of these six-month continuous tests are shown in Figure 1. 

Continuous fiber ceramic composite program United States industrial processing chemical pumps radiant burners gas filters furnace hardware reforming tubes 350°C (662°F) for 30,000 hrs in an environment containing organic and inorganic chemicals... 

The continual development of the steam reforming process ensured that this became the most practicable way to produce synthesis gas and ammonia on the large scale. A mixture of hydrocarbons and super-heated steam is passed through the reactor tubes that are packed with the nickel catalyst, and suspended in a furnace that operates at temperatures around 1000°C (Figs. 9.1 and 9.2). The steam reforming reaction is extremely endothermic and the heat of reaction must be supplied continually at a very high operating temperature. The catalyst must... 

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