Autothermal methane reformer

Beil, A. and Seume, J. (2006) Unsteady performance of a PEMFC system including autothermal methane reforming, in Proceedings of the 4th International ASME Conference on Fuel Cell Science, Engineering and Technology, June 19-21, Irvine, CA. 

Hydrocarbon Reforming 3 [HCR 3] Micro Structured Autothermal Methane Reformer... 

Hydrocarbon Reforming 4 [HCR 4] Compact Membrane Reactor for Autothermal Methane Reforming... 

Fig. 1.28. Integrated, autothermal methane reformer with cocurrent flow in the reaction zone and countercurrent heat recovery. Simulated steady-state temperature and conversion profiles.

To further illustrate typical Prox performance, results are shown from tests done with an 02/C0 ratio of 1 1 and a reactor space velocity of 440,000 h using a representative shifted reformate from an autothermal methane reformer (CO 500-10,OOOppm 02 1000-20,000ppm H20 = 32% H2 = 32% C02 = 14% ... 

Hoang DL, Chan SH (2004) Modeling of a catalytic autothermal methane reformer for fuel cell applications. Appl Catal A 268 207-216... 

Figure 11.4 Schematic representation of the two fluidized membrane reactor concepts for autothermal methane reforming with integrated CO2 capture (a) Methane combustion configuration (b) Hydrogen combustion configuration, after Patil et al.

This problem can be circumvented by using novel reactor configurations proposed by van Sint Annaland and co-workers [44, 52-54]. In particular, two configurations have been proposed to achieve autothermal methane reforming methane combustion configuration and hydrogen combustion configuration. 

The ATR (Autothermal Reforming) process makes CO-enriched syngas. It combines partial oxidation with adiabatic steam-reforming and is a cost-effective option when oxygen or enriched air is available. It was developed in the late 1950 s for ammonia and methanol synthesis, and then further developed in the 1990 s by Haldor Topspe2. The difference between Steam Methane Reforming (SMR) and ATR is in how heat is provided to activate the endothermic steam reforming reaction. In SMR, the catalyst is contained in tubes that are heated by an external burner. 

B. Glockler, G. Kolios, G. Eigenberger, Analysis of a novel reverse-flow reactor concept for autothermal methane steam reforming. Chem. Eng. Sci., 2003, 58, 593-601. 

The above reactions proceed also in the so-called rich-gas processes of British Gas and Lurgi/BASF, which convert naphtha with steam in autothermal reactions in a vessel filled with a special nickel-containing catalyst. It was formerly successfully used for town gas production from naphtha. This reaction may also used as pre-reformer ahead of a conventional tubular steam reforming furnace to convert higher hydrocarbons at low temperature and low S/C ratio into a methane reach gas which can than be reformed in the primary reformer with a standard methane reforming catalyst instead of an alkalized catalyst (Section 4.1.1.3.1). 

With the right mixture of input fuel, air, and steam, the POX reaction supplies all the heat needed to drive the endothermic catalytic steam reforming reaction. Unlike the steam methane reformer, the autothermal reformer requires no external heat source and no indirect heat exchangers. These features make autothermal reformers simpler and more compact than steam reformers and thus can be built for a relatively low capital cost. 

Autothermal reforming is a combination of partial oxidation and steam reforming carried out in a single reactor. The endothermic heat of reaction for the steam methane reforming reaction is supplied by partial oxidation of the hydrocarbon feedstock in the first section of the reactor. 

Simakov DSA, Sheintuch M (2009) Demonstration of a scaled-down autothermal membrane methane reformer for hydrogen generation. Int J Hydrogen Energy 34 8866-8876... 

Packed bed membrane reactors have been used for producing hydrogen via reforming of methane, reforming of alcohols, autothermal reforming, partial oxidation of methane, water gas shift, etc. 

The model was applied in order to investigate the influence of various parameters on the performance of FBMR with oxygen addition. Although the results showed that autothermal operation can be achieved by using approximately 0.3 O2/CH4 feed ratio, the interaction between the different parameters is quite complex. For instance, in methane reformers an important parameter is the steam/carbon ratio. However, when feeding oxygen, the steam becomes also a product of the oxidation reaction and this makes the prediction of the reactor behaviour a bit more complicated. Furthermore, an important conclusion of the work is that oxygen addition reduces the coke formation and consequently the catalyst deactivation. 

A third option is to consider an autothermal membrane reformer, where oxygen from an ASU is mixed with the methane feed and heat for reforming is provided by direct in situ oxidation of the feed, with no need of heat transfer surfaces (Fig. 10.13c). In this case, the flow of O2 to the membrane reformer can be cahbrated so that heat of endothermic and exothermic reactions exactly balance each other, and the reformed gas exits at the desired temperature. 

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