Autothermal reforming methanol

The overall equation [Eq. (2.3)] for autothermal methanol reforming is as follows for 300 °C  

It is a combination of exothermic steam reforming and endothermic partial oxidation applying a stoichiometric feed ratio which allows for an overall zero energy balance. As the exothermic reaction is faster, a hot-spot is very common in 

The benefits of applying micro structured reactors for autothermal reforming are manifold. Besides the well-known narrowing of the residence time distribution and the low pressure drops, hot-spot formation may well be reduced owing to the axial heat transfer of the wall material. 

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Autothermal Methanol Reforming 1 [AMR 1] Micro Structured Autothermal Methanol Reformer... 

Autothermal Methanol Reforming 2 [AMR 2] Micro Structured String Reactor for Autothermal Methanol Reforming... 

Figure 2.16 Methanol conversion as a function of temperature hydrogen selectivity vs. methanol conversion for autothermal methanol reforming [39] (by courtesy of ACS).

Chen et al. [36] performed a comparison of micro structured steel and aluminum plates with a conventional monolith by varying the GHSV. Full conversion could be maintained for autothermal methanol reforming in the micro structures up to a GHSV of 40 000h 1, whereas conversion dropped to 80% at 20 000h 1 at the monolith. Even at 186 000 h, still 95% conversion could be achieved in the stainless-steel micro reactor. No significant performance differences were observed between the steel and aluminum plates. 

Schuessler et al. [85] applied sintering of copper and aluminum powder to form micro structured plates for an integrated autothermal methanol reformer (see Section 2.7.2). The powders were compressed before sintering at a pressure of 1000 bar. Sintering of copper is performed at temperatures between 500 and 700 °C, which allows for the bonding of the plates in a second sintering step (see the next section). 

Schildhauer, T. J., Geissler, K. (2007). Reactor concept for improved heat integration in autothermal methanol reforming. International Journal of Hydrogen Energy, 32, 1806-1810. 

Lindstrom et al. [55] developed a fixed-bed autothermal methanol reformer designed for a 5 kW fuel cell operated with copper/zinc oxide catalyst doped with zirconia. The system was started without preheating from ambient temperature by methanol combustion in a start-up burner, which was operated at sixfold air surplus to avoid excessive temperature excursions. Because significant selectivity toward carbon monoxide was observed for the autothermal reforming process, a WGS stage became mandatory [55]. 

Borup et al. [193] demonstrated that it is possible to heat up an autothermal methanol reformer equipped with a precious metal based catalyst from room temperature, when the O/C ratio of the feed exceeds 1.45. The S/C ratio was set to 1.0 for these investigations. The exothermic oxidation reactions clearly started even at ambient temperature and caused light-off of the reformer. 

Lindstrom et al. developed a fixed-bed autothermal methanol reformer designed for a 5-kWei fuel cell [ 168]. The system was started, without pre-heating, from ambient... 

Homg described the start-up behaviour of their monolithic autothermal methanol reformer [479]. The ceramic monolith was coated with a mixed platinum and copper/ zinc oxide catalyst. The monolith had 117-mm diameter and 50-mm length, while the whole reactor was more than 510-mm long. Glow plugs were used for the start-up. 

Figure 7.3 Monolithic autothermal methanol reformer prepared by Lyubovski et al. [190] the gases are fed Into the centre of the reactor and pass through It In a radial direction.

Autothermal methanol reforming for hydrogen production in fuel cell applications. Phys. Chem. Chem. Phys.,... 

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