Methanol fuel handling

The electrocatalytic oxidation of methanol has been widely investigated for exploitation in the so-called direct methanol fuel cell (DMFC). The most likely type of DMFC to be commercialized in the near future seems to be the polymer electrolyte membrane DMFC using proton exchange membrane, a special form of low-temperature fuel cell based on PEM technology. In this cell, methanol (a liquid fuel available at low cost, easily handled, stored, and transported) is dissolved in an acid electrolyte and burned directly by air to carbon dioxide. The prominence of the DMFCs with respect to safety, simple device fabrication, and low cost has rendered them promising candidates for applications ranging from portable power sources to secondary cells for prospective electric vehicles. Notwithstanding, DMFCs were... 

It is also toxic and a few teaspoons of methanol consumed orally can cause blindness. A few tablespoons can be fatal, if not treated. Methanol is also very corrosive, so it requires a special fuel-handling system. 

Direct-methanol fuel cells (DMFCs) have attracted considerable attention for certain mobile and portable applications, because of their high specific energy density, low poison emissions, easy fuel handling, and miniaturization [129,130], However, the methanol permeation through electrolyte membranes (usually called methanol cross-over) in DMFCs still is one of the critical problems hindering the commercialization [131,132], Nafion , a... 

Therefore, methanol is the top candidate because of its low price, less toxicity, high energy density and easy handling. Although direct methanol fuel cells may need an auxiliary system to treat unoxidized or partially oxidized fuel in the exhaust gas, direct methanol fuel cells are still a very attractive system as a portable power source. 

The storage, transportation, and handling of H2 are difficult. It has been reported that between H2 production and H2 application, a 15% loss due to leakage is unavoidable. Liquid methanol has advantages over H2 in this respect, and direct methanol fuel cells are presently believed to be the ideal energy converting alternatives to hydrogen PEMFCs. 

The existing methanol infrastructure could handle some methanol fuel cell cars at a low cost of about 50 per car. But any significant use of methanol as a transportation fuel would require additional investments in fuel production and delivery, which may be somewhat less than a hydrogen infrastructure. 

An alternative to the use of H2 as fuel is methanol, which is a liquid fuel and easy to handle. This can be directly transformed to electrical current in a DMFC (direct methanol fuel cell). The DMFC allows a simple system design. However, presently achieved performance data of DMFC is not satisfactory and material costs are too high. As another alternative, methanol or hydrocarbons (e.g. natural gas, biogas) can be transformed to hydrogen on board the electric vehicle by a reformation reaction. This allows use of the H2-PEFC cell, which has a higher level of development. The reformate feed gas may contain up to 2.5% carbon monoxide (CO) by volume, which can be reduced to about 50ppm CO using a selective oxidizer (Wilkinson et al. [1997]). 

A slurry is a mixture of a liquid and solid particles. The term sludge typically refers to a highly concentrated slurry containing fine particulate material. Each year, vast tonnages of slurries are pumped. Slurries are often used to transport coal, phosphates and minerals. Dredging of sand and silt in the maintenance of waterways is another example of sohds handled in slurry form. In most slurries, the liquid phase is water. However, coal-oil and coal-methanol fuels are examples of slurries made up with liquids other than water. 

Direct methanol fuel cells (DMFC) on the other hand represent the only class of fuel cells in which one of the reactants is provided in liquid phase, compared with the other, gas-fed cell types. Due to the comparatively easy handling of methanol, DMFCs are mostly considered for portable and mobile applications. Their reduced power density when compared to hydrogen-driven PEMFCs (the current density is around one-tenth of that compared to PEMFCs) leads usually to... 

Natural gas, which is mostly methane, is widely used as a fuel. In the chemical industry, methane is used heavily as a raw material for making important products that include acetylene, ammonia, ethanol, and methanol its chlorination also yields carbon tetrachloride, chloroform, methyl chloride, and methylene chloride. It is used to produce carbon black for use in the manufacture of rubber products and printing inks. The burning of high-purity methane is used to make carbon black of special quality for electronic devices. Natural gas has seen limited use as a motor fuel handled as a compressed gas in high pressure cylinders or liquid dewars. 

Progress in the area of membrane hydrogen-oxygen fuel cells led to the development of fuel cells of a new type, direct methanol fuel cells (DMFCs), in which methanol is oxidized directly. The more convenient liquid fuel replaces hydrogen, a fuel that is inconvenient to handle, store, and transport. 

The chief issues facing fuel methanol in the field of safety involve fire properties and human toxicity, each of which are prime concerns when the general public is ejqtosed to fuel handling. Fortunately, a eonsiderable amount of work has been performed on both topics, with the broad eonelusion that methanol is safer than gasoline but less safe than diesel... 

Many properties of methanol are of little importance to its chemical applications but can be critical to its success as a fuel Table 10 lists a variety of physico-chemical parameters that must be considered in the context of transportation fuel Broadly, such considerations center around engine technology, fuel handling, and human exposure risk. 

Until these materials have been developed, one attractive fuel is methanol, which is easy to handle and is rich in hydrogen atoms ... 

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