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A mixture of water and methanol with a molar concentration ratio (water:methanol) of 1.0 - 1.5 is pressurized to approximately 20 bar, vaporized and heated to a temperature of 250 - 360 °C. The hydrogen that is created is separated through the use of Pressure swing adsorption or a hydrogen-permeable membrane made of polymer or a palladium alloy.
The fuel cartridge stores the methanol fuel. Depending on the system design either 100% methanol (IMPCA industrial standard) or a mixture of methanol with up to 40 vol% water is usually used as fuel for the RMFC system. 100% methanol results in lower fuel consumption than water-methanol mixture (Premix) but goes along with higher fuel cell system complexity for condensing of cathode moisture.
However, it is used as a source of hydrogen in some types of fuel cell; it can generate a higher voltage than methanol, which is the fuel of choice for most alcohol-based fuel cells. However, since propanol is harder to produce than methanol (biologically or from oil), methanol-utilizing fuel cells are preferred over those that utilize propanol.
Methods include hydrogen produced through an electrolysis, storing hydrogen on the vehicle as a second fuel, or reforming conventional fuel into hydrogen with a catalyst. There has been a great deal of research into fuel mixtures, such as gasoline and nitrous oxide injection. Mixtures of hydrogen and hydrocarbons are no exception.
Efforts are being made to convert "waste" natural gas into methanol, providing an efficient means of utilizing excess resources. While some methanol is produced by fermenting biomass, it is not yet economically competitive. Notably, M85 has the potential to be a preferred means of storing hydrogen for fuel-cell electric vehicles in the future.
Hydrogen with low purity can be used as fuel. Hydrogen with low purity is cheaper than high purity hydrogen which has to be usually used for LT-PEM fuel cell. The use of fuels like methanol makes cheaper fuel costs per kWh possible compared with hydrogen (e.g. LT-PEM fuel cells) or diesel (e.g. gensets) as fuel.
Catalytic reforming is quite different from and not to be confused with the catalytic steam reforming process used industrially to produce products such as hydrogen, ammonia, and methanol from natural gas, naphtha or other petroleum-derived feedstocks.
In contrast to indirect methanol fuel cells, where methanol is reacted to hydrogen by steam reforming, DMFCs use a methanol solution (usually around 1M, i.e. about 3% in mass) to carry the reactant into the cell; common operating temperatures are in the range 50 to 120 °C (122 to 248 °F), where high temperatures are usually pressurized.