Fuel methanol/ethanol reforming

Oxidation of Alcohols in a Direct Alcohol Fuel Cell The electrocatalytic oxidation of an alcohol (methanol, ethanol, etc.) in a direct alcohol fuel cell (DAFC) will avoid the presence of a heavy and bulky reformer, which is particularly convenient for applications to transportation and portable electronics. However, the reaction mechanism of alcohol oxidation is much more complicated, involving multi-electron transfer with many steps and reaction intermediates. As an example, the complete oxidation of methanol to carbon dioxide ... 

In addition to the direct use of ethanol as a fuel, its use as a source of H2 to be used with high efficiency in fuel cells has been thoroughly investigated. H2 production from ethanol has advantages compared vdth other H2 production techniques, including steam reforming of hydrocarbons and methanol. Unlike hydrocarbons, ethanol is easier to reform and is also free of sulfur, which is a well-known catalyst poison. Furthermore, unlike methanol, ethanol is completely renewable and has lower toxicity. 

Most fuel cells are powered by hydrogen, which can be fed to the fuel cell system directly or can be generated within the fuel cell system by reforming hydrogen-rich fuels such as methanol, ethanol, and hydrocarbon fuels. Direct methanol fuel cells (DMFCs), however, are powered by pure methanol. 

A purge is taken from the synthesis loop to remove inerts (nitrogen, methane), as well as surplus hydrogen associated with non-stoichiometric operation. The purge is used as fuel for the reformer. Crude methanol from the separator contains water, as well as traces of ethanol and other... 

Methanol and ethanol have been considered as promising fuels for generating H2, especially for on-board fuel cell applications due to their easy availability, ability to transport, and reaction simplicity.52 121 159 169 For example, both alcohols have high H2-to-carbon ratio (H/C) of 4 and 3, respectively (Table 2.1). They could be synthesized from renewable sources such as biomass and thus the ability to close the carbon cycle.161 166 Unlike hydrocarbon fuels, methanol and ethanol are free from sulfur, and this avoids additional sulfur removal step in the fuel processing. In addition, methanol can be reformed at a lower temperature, around 300 °C, and this makes the fuel processing relatively simple and less complicated. Furthermore, unlike natural gas, which produces primarily syngas, reforming of methanol and ethanol can in principle produce a mixture of H2 and C02, and this would also simplify the downstream CO cleanup for fuel cells such as PEMFCs where CO is a poison. 

As discussed above in the reforming of hydrocarbon fuels, H2 can be produced from alcohol fuels by at least three major catalytic processes, namely steam reforming, partial oxidation and ATR or oxidative steam reforming. The chemistry, thermodynamics, and recent developments in catalysis of methanol and ethanol reforming with steam for H2 production will be discussed in this section. 

Lab-scale experiments have demonstrated the feasibility of a wide range of fuels for CPO reformers. Some of the fuels examined are methane, ethanol, methanol, JP-8, diesel, and bio-oil or biodiesel. Products from different fuels can be tuned toward either syngas or olefins by changing the 02/C, steam/C ratio, and the catalyst.20,21... 

Although focused on gasoline operation, the fuel processing system will utilize fuel-flexible reforming technology that can be modified to accommodate fuels such as methanol, ethanol and natural gas... 

Fuel flexibility of the fuel reforming subsystem was demonstrated using methane, propane, butane, methanol, ethanol, isooctane, and benchmark gasoline. A 1000-hour catalyst and reactor durability test was completed using benchmark gasoline. Warm transient response of less than 5 seconds was achieved for 10 to 90% of full reformer capacity. A three-fold increase in reformer productivity was achieved compared to the previous year, due to improved catalyst performance and more uniform flow within the reactor. Reactor concepts that would meet FreedomCAR s rapid start-up targets were developed. 

Fuel delivery systems include hydrogen (electrolyzers, bottles, pipelines, reformate and others), natural gas, propane, methanol, ethanol, anaerobic digester gas (ADG), diesel, bio-diesel, gasoline, landfill methane, and jet fuels... 

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. 

It is under development for various fuels such as methanol, ethanol, LPG and gasoline. The complete fuel processor was composed of a catalytic autothermal reformer reactor, a heat exchanger for cooling the reformate downstream of the CAR,... 

Laosiripojana, N., Assahumrungrat, S. (2007). Catalytic steam reforming of methane, methanol, and ethanol over Ni/YSZ the possible use of these fuels in internal reforming SOFC. Journal of Power Sources, 163, 943—951. 

Theoretical calculations to evaluate internal reforming of methanol, ethanol and methane for molten carbonate fuel cells were performed by Maggio et al. [45]. 

Unlike methanol, it is considered non-toxic. Its availability and cost as a fuel are irregular more important, ethanol cannot be processed at the low temperatures characteristic of methanol steam reforming. Therefore, its potential attractiveness as a fuel for compact fuel cell... 

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