Integral reactor carbon monoxide oxidation

Preferential Carbon Monoxide Oxidation 5 [PrOx 5] Integrated Heat Exchanger/Reactor for PrOx... 

Oh, Se H., Hegedus, L. L., Baron, K. and Cavendish, J. C., "Carbon Monoxide Oxidation in An Integral Reactor. Transient Response to Concentration Pulses in the Regime of Isothermal Multiplicities" Proc. ISCRE5 ACS Symposium Series 65,... 

At the cold start of the engine the catalyst is not able to oxidize carbon monoxide and hydrocarbons present in the exhaust. Therefore, zeolites are added into y-Al203-based catalytic washcoat for HC adsorption at low temperatures, resulting in an integrated adsorber-reactor system (Jirat et al., 2001 Kryl et al., 2005). For optimum operation of such a system, the consecutive HC desorption induced by increasing temperature should not occur earlier than the catalyst light-off. 

Figure 2.60 Integrated reactor/heat exchanger for the preferential oxidation of carbon monoxide developed by Eindhoven University and IMM [89] (source IMM).

Schuessler et al. [85] of XCELLSiS (later BALLARD) presented an integrated methanol fuel processor system based on autothermal reforming, which coupled fuel/water evaporation with exothermic preferential oxidation (PrOx) of carbon monoxide. The reactor technology was based, in contrast to most other approaches, on a sintering technique. 

This system includes several mixing and heat exchange units. A concept for an integrated, microtechnology-based fuel processor was proposed by PNNF [8]. As examples for unit operations which may be included in future integrated systems the same publication mentions reactors for steam reforming and/or partial oxidation, water-gas shift reactors and preferential oxidation reactors for carbon monoxide conversions, heat exchangers, membranes or other separation components. 

Figure 1 Indicates the results of a run (made at 699 C after 28 oxidations of the stainless steel reactor and also described In Table II). Over half of 60 cc/mln of feed carbon monoxide reacted Initially and approximately 90X of the carbon dioxide produced was by Reaction 8 (disproportionation reaction or Boudouerd reaction). After about one hour, almost all of the reaction was by Reaction 8. Then the moles of carbon monoxide that reacted by Reaction 7 first Increased and then decreased as shown In Figure 1. After about four hours. Reaction 7 became and remained the predominant reaction for the remainder of the run that lasted for 12 hours. The areas under the curves of Figure 1 were Integrated to make material balances. 1570 millimoles Oo/sq. meter were removed from the surface, and 7500 millimoles carbon/sq. meter were deposited (see Table II).

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