Microreactors steam reforming

The main part of the fuel processing system is the reformer that produces the hydrogen needed for the fuel cells, no matter what power is needed. Generally, there are three routes for the fuel conversion in microreactors steam reforming, catalytic partial oxidation and oxidative steam reforming. 

Steam reforming is generally the preferred process for hydrogen production.Particularly for portable hydrogen production, the requirement of an external heat source can be addressed through the advanced heat and mass transfer provided by microreactors. 

Pfeifer, P., Schubert, K., Liauw, M.A., Emig, G., Electrically heated microreactors for methanol steam reforming, Trans. IChemE 2003, 81A, 711-720. 

L., Renken, A., Catalyst coating in microreactors for methanol steam reforming kinetics, in Matlosz, M., Ehrfeld, W., Baselt, J. P. (Eds.), Microreaction Technology - IMRET 5 Proc. of the 5th International Conference on Microreaction Technology, Springer-Verlag, Berlin, 2001, 322-331. 

Find, J., Lercher, J. A., Cremers, C., Stimming, U., Kurtz, O., Cramer, K., Characterization of supported methane steam reforming catalyst for microreactor systems, in Proceedings of the 6th International Conference on Microreaction Technology, IMRET 6 (11-14 March 2002), AIChE Pub. No. 164, New Orleans, 2002, 99-104. 

Both clean and sulfur-poisoned catalysts were then used in 24 and 166 hour steam reforming runs at. 490 C and 25 atm with a sulfur-free naphtha feedstock. The experimental apparatus consists of a fixed bed microreactor made of stainless steel for high pre Esure runs. During each run, the catalyst activity was monitored by analyzing the reactor effluent using an on-line quadrupolc mass spectrometer as well as by gas chromatography ... 

FIGURE 23 Scheme of a single channel microreactor for methane steam reforming [182]. (Adapted with permission from Elsevier.)... 

Catalytic activity measurements in CH steam reforming were carried out at T - 625°C (PR - 1.1 bar) in a continuous flow microreactor operating at GH5Y = 150.000 h"1 with P = Z-54. Before test, catalysts were reduced... 

Dominguez M, Cristiano G, Ldpez E and Llorca J (2011), Ethanol steam reforming over cobalt talc in a plate microreactor , Chem EngJ, 176-177,280-285. 

Levent M, Gunn D J and El-Bousiffl M A (2003) Production of hydrogen-rich gases from steam reforming of methane in an automatic catalytic microreactor , Int J Hydrogen Energy, 28,945-959. 

Tadbir M A and Akbari M H (2011), Methanol steam reforming in a planar wash coated microreactor integrated with a micro-combustor , Int J Hydrogen Energy, 36,12822-12832. 

Wang J, Liu G, Xiong Y, Huang X, Guo Y and Tian Y (2008), Fabrication of ceramic microcomponents and microreactor for the steam reforming of ethanol . 

Zhou W, Tang Y, Pan M, Wei X, Chen H and Xiang J (2009), A performance study of methanol steam reforming microreactor with porous copper fibre sintered felt as catalyst support for fuel cells , Int J Hydrogen Energy, 4, 9745-9753. 

Due to the excellent heat transfer capabilities of microreactors, most studies utilizing them for hydrogen production have dealt with the steam reforming of various hydrocarbons, including gaseous and liquid fuels such as methane, methanol, ethanol, natural gas, gasoline and diesel. 

Reuse et al. [16] applied a self-developed reactor carrying microstructured plates for the determination of methanol steam reforming kinetics over a commercial copper-based low-temperature water gas shift catalyst from Siid-Cliemie. Kinetic expressions were determined for both a tubular fixed-bed reactor containing 30 mg of catalyst particles and the microreactor coated with the catalyst particles. A power law... 

Table 24.1 Reaction order of fixed bed and microreactor determined by Reuse et at. [17] for methanol steam reforming.

The above theoretical and practical investigations demonstrate the potential improvements achievable with microreactor technology, especially in the case of steam reforming. 

Similarly to catalyst development, activities dealing with integrated reactors and complete systems for steam reforming in microreactors are dominated by systems applying methanol as fuel, ethanol steam reformers being the exception. 

Kundu et al. at Samsung [54] developed a microreactor for methanol steam reforming in the power range 5-10 W. The microreformer was 30 mm wide and long and comprised evaporation and steam reforming zones. Parallel and serpentine channels for steam reforming were tested alternatively the serpentine arrangement... 

Recent research in packed beds [38], ceramic monoliths [20] and microreactors [30] also revealed an excellent performance of a Ce-Zr support mixture, which was explained by an increase in surface area by the addition of zirconium oxide [38]. A zirconium oxide-supported rhodium catalyst also revealed similar ignition performance to a mixed Ce-Zr oxide supported rhodium catalyst on the surface of Fecralloy monoliths with trapezoidal channels [9]. A novel route to a support, which might be useful for CPO and OSR, is the synthesis of silicon carbide foam, recently used for steam reforming [44] (Figure 25.2). This support would also be less acidic and is suitable for building a compact foam catalyst... 

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