Methanol fuel safety

It is not the purpose of this paper to evaluate the suitability of methanol as a fuel for gas turbines. Consequently, no attention will be given to such factors as the cost of methanol fuel, safety considerations of exchanging heat between hot exhaust gases and fuel, and the dynamics of the complex cycle with recuperative chemical reactions. The purpose of this paper is to outline the thermodynamic Implications of chemical recuperation using methanol fuel as an example. 

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... 

E. R. Fanick, L. R. Smith, J. A. Russell and W. E. Likos, "Laboratory Evaluation of Safety-Related Additives for Neat Methanol Fuel," SAE Paper 902156, (SP 840), Society of Automotive Engineers, Warrendale, Pa., Oct. 1990. 

So as it can not be considered to provide a fuel cell functioning at higher temperatures than 80 or even 100°C for the user s safety, the choice in the type of fuel cell to use in portable devices is limited to low temperature fuel cells such as PEMFC (for Proton Exchange Membrane Fuel Cell or sometimes Polymer Electrolyte Membrane Fuel Cell) and DMFC (for Direct Methanol Fuel Cell). 

Because of the higher energy density and better safety of liquid fuels compared with gaseous hydrogen, the types of fuel cell under active development usually includes direct methanol fuel cells (DMFCs) [4], direct formic acid fuel cells (DFAFCs) [5], proton exchange fuel cells (PEMFCs) run by hydrogen generated from metal hydride [6], and membraneless microfluidic fuel cells [7]. 

As is clear from the previous discussion, the use of gas as a fuel presents problems of electrode construction and storage, that are not there when the fuel is water soluble. Three substances have been seriously suggested as such fuels—methanol, hydrazine and ammonia. Of these, methanol will probably become more accepted than the other two, mainly for economic and safety reasons. Methanol, if it becomes widely used for fuel cell operation, is likely to drop in price markedly, while hydrazine and ammonia will probably not. This section will describe briefly the methanol fuel cell, although the technology of the hydrazine one is more advanced. 

In reviewing the fiiU range of health and safety issues associated with all alternative fuels, the California Advisory Board determined that there were no roadblocks that would prevent the near term deployment of either methanol or ethanol, assuming that adequate safety practices were foUowed appropriate to the specific nature of each fuel (14). 

P. A. Machiele, "A Health and Safety Assessment of Methanol as an Alternative Puel," ia W. Kohl, ed.. Methanol as an yiltemative Fuel yin yissessment, ]oim. Hopkias Poreiga PoHcy lastitute, Washiagtoa, D.C., 1990, pp. 217—239. 

Chapter one is an overview of the energy evolution. It introduces the technology and emission issues, safety, and alternative fuels such as natural gas, hydrogen gas, methanol, ethanol and fuel cell power. 

Alternative fuel programs is the theme of Chapter three. Subjects include hydrogen, methanol, syn gas, biofuels, fueling methods, safety and storage. The chapter ends with a discussion of cost issues. 

Methanol, which is also known as wood alcohol, is a colorless and odorless liquid alcohol fuel that can be made from biomass, natural gas, or coal. It is the simplest alcohol chemically and it may be used as an automobile fuel in its pure form (Ml 00), as a gasoline blend of typically 85% methane to 15% unleaded gasoline (M85). It is also used as a feedstock for reformulated gasoline. M100 or pure methanol may be used as a substitute for diesel. In M85, the gasoline is added to color the flame of burning fuel for safety reasons and to improve starting in cold weather. 

Fuel cells using directly liquid fuels are advantageous in this aspect. Methanol, formaldehyde (water solution), formic acid (water solution) and hydrazine are among fuels relatively easy to oxidize electrochemically. Alcohol and hydrocarbon with larger molecular weight are much harder to oxidize completely to C02- Other qualifications to be considered are price, availability, safety, energy density and ease of handling. 

Each of the fuels other than methanol have serious problems hydrazine price and safety formaldehyde safety and energy density formic acid energy density and safety. 

Due to methanol s corrosivity and its affinity for water, it cannot be readily distributed in today s fuel infrastructure. Methanol burns with a nearly invisible flame. Available luminosity additives won t reform in the low-temperature methanol steam reformers. Methanol is more acutely toxic than gasoline. Additives that are likely to be needed for safety and health reasons will impact the fuel processor s performance and cost. 

Methanol bums without a visible flame, which is a safety concern, but which also demonstrates that methanol does not produce soot or smoke when combusted. This fact makes methanol a very attractive diesel engine fuel because, unlike diesel fuel, no fuel particulates are formed. Recent health effects studies suggest that particulate matter is a health hazard regardless of whether known... 

Machiele, P.A., Summary of the Fire Safety Impacts of Methanol as a Transportation Fuel, SAE Paper No. 901113 Society of Automotive Engineers 400 Commonwealth Drive Warrendale, Pennsylvania 15096-0001 Phone 412-776-4841... 

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