Catalytic reformer off-gas

Natural gas enrichment (CO2/CH4 membrane separation) is employed to remove CO2 from natural gas streams as well as for recovering CO2 in enhanced oil recovery processes. Methane recovery from landfill sources is an additional application. Membranes are employed for hydrogen recovery in ammonia ptuge gas, H2/CO ratio adjustments in hydrogen production (HYCO process), in hydrocracker and hydrotreater ptuge gas, and in catalytic reformer off-gas. With the very high permeability of water versus common gases, membranes have fotmd applications for air dehydration and natural gas dehydration. Additional applications include helium recovery and H2S removal from natural gas. 

This reaction is endothermic and is favored by low pressure. In practice, however, the process is conducted at a pressure of 1-3 MPa (because of a concurrent hydrocracking reaction) and a temperature of 300-450°C using Pt-based catalysts [7]. The feedstock for the reforming process must be carefully purified from S- and N-compounds (below 1 ppm), which may use up a significant portion of hydrogen produced. The typical composition of the off-gas from the catalytic reforming of naphtha is as follows (vol%) H2—82, CH4—7, C2—5, C3—4, and C4—2 [7]. 

In a catalytic de-alkylation process, toluene or Q aromatics (alkylben-zenes) are fed to a reactor, together with a hydrogen-containing gas. See Fig. 1. The hydrogen source is not critical and may be manufactured hydrogen or off-gas from a reforming or other refining unit. Effluent from the... 

In petroleum refineries, off-gas streams from catalytic reforming processes represent the largest source of recoverable hydrogen, exceeding by a wide margin the amount of make up hydrogen produced by steam reforming and partial oxidation. 

Hydrogen make-up stream shown is the stoichiometric chemical consumption in the octafiner. Typical source of this stream is the off-gas produced from a catalytic reformer with a hydrogen content in the range of 75-95 mole %. 

Delsman et al. investigated the advantages of a microstructured methanol reformer coupled with a catalytic burner for anode off-gas over a conventional fixed-bed system [36]. Two ranges of electrical power output of the corresponding fuel processor-fuel cell system were considered, namely 100 W and 5kW. The calculations revealed a more than 50% lower reactor size and more than 30% less catalyst mass required for the microreactor in case of the 100 W system. For the 5 kW system, the reactor volume was only 30% lower, but the catalyst savings were up to 50%. 

Figure 24.11 shows a microstructured coupled diesel steam reformer/catalytic afterburner developed by Kolb et al. [27], which was operated at temperatures exceeding 800 ° C. The reactor, which was coated with catalyst from Johnson-Matthey Fuel Cells, had separate inlets for anode off-gas and for air supply to the burner. Full conversion of the diesel fuel was achieved for a total operation time of 40 h with this reactor, which had a power equivalent of 2 kW thermal energy of the hydrogen produced. 

When catalyst is introduced on to the walls of the second flow path, a catalytic wall reactor is formed, as shown in Figure 7.3c. This design has enormous potential for directly coupling exothermic reactions (such as steam reforming) and exothermic reactions (such as catalytic combustion of fuel cell anode off-gas), which are then only separated by the few hundred micrometer metal foils between the two coatings. 

Combustion of anode off-gas in a catalytic afterburner or in a burner integrated into a steam reformer or evaporator, which could be achieved by plate heat-exchanger... 

A second generation system, as shown in Figure 5.61. It was composed of a microchannel oxidative steam reformer, which was supplied with water by a humidifier. The humidifier utilised cathode off-gas for humidification. Steam reforming was performed at a S/C ratio of 1.6 and O/C ratio 0.2. The microchannel steam reformer was coupled to an integrated catalytic burner The burner was... 

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