“…Fuel processors being developed at Battelle provide 15 W to over 100 W equivalents of hydrogen from methanol fuel. ,− Two architectures based on microchannel technology 14,15 were used in this work (Figures and ), which enabled a scalable fabrication over this wide range. The processors consisted of fuel vaporizers and preheaters for both the combustion reactants and steam reforming reactants, a combustor, a steam reformer, heat exchangers, and recuperators. ,− The reactors were assembled using a combination of welding, brazing, and diffusion bonding techniques, although the specifics of the techniques and the laminate layer designs are not reported. 17 25−50 W integrated fuel processor …”
Section: 32 Battelle Pacific Northwest Division 15−100 W
Power Genera...mentioning
“…Fuel processors being developed at Battelle provide 15 W to over 100 W equivalents of hydrogen from methanol fuel. ,− Two architectures based on microchannel technology 14,15 were used in this work (Figures and ), which enabled a scalable fabrication over this wide range. The processors consisted of fuel vaporizers and preheaters for both the combustion reactants and steam reforming reactants, a combustor, a steam reformer, heat exchangers, and recuperators. ,− The reactors were assembled using a combination of welding, brazing, and diffusion bonding techniques, although the specifics of the techniques and the laminate layer designs are not reported. 17 25−50 W integrated fuel processor …”
Section: 32 Battelle Pacific Northwest Division 15−100 W
Power Genera...mentioning
“…This includes battery replacement, e.g., as energy source for laptops (see also [181]) or energy supply for households without mains connection (stand-alone supply). Among the components developed are a micro evaporator (volume 0.3 l) for a 50 kW fuel cell [180], a microheater (weight 200 g) for 30 W power and 85 % efficiency [188], and portable energy sources with 10 to 100 W power (base unit of: 21 cm length) [174] and [189]. A compact steam reforming reactor (total size 4 l) for automobile applications achieves a conversion of 90 % concerning isooctane and serves for supply of a 50 kW fuel cell [167].…”
Over the last five years, many activities have focused on the unexploited field of carrying out reactions on small scales. Due to the rapid development of new components, this paper deals with recent developments only in a compressed form. An important point is the analysis of possible plant concepts for microreactors and whether these are a sensible option. Due to the enormous difference in size between the microchannels and the fluid periphery of possible components this is not just a technical question. It touches on the microtechnology concept as a whole. The direction in which the field should be developed and which measures can be taken to influence its development are questions that are addressed here with respect to the big industrial interest in microreactors.
Reactors for Photochemical and Electrochemical ProcessingMicroreactors may possibly be capable of reevaluating processes which so far have been poorly developed both in the lab and in the chemical industry. Among such processs certainly are electrochemical reactions and particularly photochemical reactions.
Photochemical and Electrochemical ProcessesIn view of the low quantum yield of photochemical processes even for respective lab-scale equipment, it would appear that guiding of thin fluid layers in transparent microreactors, e.g. mixer-reactors, in close proximity to a radiation source should be beneficial. At the Massachusetts Institute of Technology (MIT), Cambridge (USA), researchers carried out the pinacol synthesis using benzophenone as reactant in a pyrex/silicon microreactor equipped with a miniature UV lamp (k = 366 nm) (see Fig. 20) [98,99].An electrochemical microreactor was developed at IMM which combines the advantages of thin-layer cell technology (namely, current efficiencies up to 100 %, absence of conducting salt) and microchemical processing (e.g., isothermal processing, good mass transfer). The electrochemical microreactor has a parallel-plate architecture. Using this device, an increase in selectivity for the synthesis of anisaldehyde from 4-methoxytoluene was detected [100].
Heat Transfer
Fast Heating up for Chlorination of AlkanesThe chlorination of alkanes [102] performed by the Axiva company serves as a good and successful example based on the motto ªas much miniaturization as necessary, not as possibleº. The tube reactors used till now needed too much time to reach a certain temperature level or even exhibited temperature maxima above the target value, in effect similarly detrimental as a hot spot. To improve these features, IMM developed monolithic heating modules that are externally heated. The . UV absorption of reaction mixtures resulting from pinacol reaction using benzophenone in isopropanol at various flow rates and residence times, respectively. A comparison of these results to HPLC measurements at the same mixtures reveals that these UV in-line spectra are accurate and hence can be used to monitor the course of reaction. Source: K. Jensen, MIT, Department of Chemical Engineering, Cambridge (USA)
“…Fuel cells are being considered as battery replacements for some of these applications because of their high efficiency and environmentally benign operation. [8][9][10] The primary idea of an integrated microchemical device (fuel processor plus fuel cell) is to convert chemical energy into electricity. Hydrogen-based proton exchange membrane (PEM) fuel cells show good potential for the production of electricity.…”
Section: Introductionmentioning
confidence: 99%
“…Hydrogen-based proton exchange membrane (PEM) fuel cells show good potential for the production of electricity. [8][9][10] However, widespread commercialization of portable PEM fuel cells will depend on the cheap and environmentally benign production of hydrogen at the small scale based on some type of a microreactor. The higher energy density of hydrocarbons, methanol, and ammonia (nearly 100-fold) compared to conventional Li-based batteries makes them ideal candidates for the production of hydrogen and eventually electricity.…”
Ammonia decomposition for the production of hydrogen in a newly fabricated, aluminum
framework post microreactor is modeled. A detailed microkinetic model describing the chemistry
of ammonia decomposition on Ru is developed. A PFR model is used as a low hierarchical tool
for developing a reduced rate expression using a computer-aided methodology. This reduced
chemistry model is used in computational fluid dynamics simulations of microreactors, and good
agreement with experimental data is observed. It is found that the overall conversion in the
post microreactor better approximates that of a PFR than that of a CSTR. It is shown that the
posts play an important role in enhancing the transverse mass transfer and providing a high
catalyst surface area and that interesting flow patterns and back-diffusion occur at lower flow
rates. Finally, parametric studies are performed, and a tradeoff between pressure drop and
conversion is observed under certain conditions.
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