Dimethyl ether fuel

The chemical recycling of carbon dioxide into usable fuels provides a renewable carbon base to supplement and eventually replace our diminishing natural hydrocarbon resources. Methanol (or dimethyl ether), as discussed, can be readily converted into ethylene or, by further reaction, into propylene. 

By selection of appropriate operating conditions, the proportion of coproduced methanol and dimethyl ether can be varied over a wide range. The process is attractive as a method to enhance production of Hquid fuel from CO-rich synthesis gas. Dimethyl ether potentially can be used as a starting material for oxygenated hydrocarbons such as methyl acetate and higher ethers suitable for use in reformulated gasoline. Also, dimethyl ether is an intermediate in the Mobil MTG process for production of gasoline from methanol. 

Oxygenates and Chemicals A whole host of oxygenated products, i.e., fuels, fuel additives, and chemicals, can be produced from synthesis gas. These include such produc ts as methanol, ethylene, isobutanol, dimethyl ether, dimethyl carbonate, and many other hydrocarbons and oxyhydrocarbons. Typical oxygenate-producing reactions are ... 

Many GTL-derived fuels are being considered for blending with gasoline and diesel to achieve emission reductions of particulate matter (PM), carbon monoxide (CO), nitrogen compounds (NOx) and nonmethane hydrocarbons (NMHC). The most promising fuels converted from natural gas are methanol and ethers such as dimethyl ether (DME) and mcthyl-t-bntyl ether (MTBE). 

Dimethyl ether is used as a propellant in aerosols. It is also a solvent, a fuel used in welding, and a refrigerant. In high concentrations, it has an anesthetic effect. 

Cool, T.A. et al., Photoionization mass spectrometry and modeling studies of the chemistry of fuel-rich dimethyl ether flames, Proc. Combust. Inst., 31,285,2007. 

Fuel industry is of increasing importance because of the rapidly growing energy needs worldwide. Many processes in fuel industry, e.g. fluidized catalytic cracking (FCC) [1], pyrolysis and hydrogenation of heavy oils [2], Fischer-Tropsch (FT) synthesis [3,4], methanol and dimethyl ether (DME) synthesis [5,6], are all carried out in multiphase reactors. The reactors for these processes are very large in scale. Unfortunately, they are complicated in design and their scale-up is very difflcult. Therefore, more and more attention has been paid to this field. The above mentioned chemical reactors, in which we are especially involved like deep catalytic pyrolysis and one-step synthesis of dimethyl ether, are focused on in this paper. 

There is a need to seek an environmentally benign, technically feasible and economical alternative fuel because of the limited crude oil reserves and serious pollution all over the world. Recently, dimethyl ether (DME) is proved to be used as an alternative clean fuel in transportation, power generation and household use for its excellent behavior in compression ignition for combustion, cetane number of over 55 and zero sulfur content, and is praised as a super-clean fuel in the 21 century. It has a promising foreground of application. Therefore, the efficient synthesis of DME from syngas derived from natural gas, coal or biomass has drawn much attention. 

Air Products and Chemicals, Inc. Liquid Phase Dimethyl Ether Demonstration in the LaPorte Alternative Fuels Development Unit., January 2001. 

TIGAS [Topsoe integrated gasoline synthesis] A multi-stage process for converting natural gas to gasoline. Developed by Haldor Topsoe and piloted in Houston from 1984 to 1987. Not commercialized, but used in 1995 as the basis for a process for making dimethyl ether for use as a diesel fuel. 

Methanol has been considered as a fuel for fuel-cell vehicles with on-board fuel processors for some time. Dimethyl ether (DME) has been suggested as a fuel alternative for diesel engines in Japan and Sweden. The synthesis of DME is based on methanol synthesis followed by DME formation ... 

Depending on the reason for converting the produced gas from biomass gasification into synthesis gas, for applications requiring different H2/CO ratios, the reformed gas may be ducted to the water-gas shift (WGS, Reaction 4) and preferential oxidation (PROX, Reaction 5) unit to obtain the H2 purity required for fuel cells, or directly to applications requiring a H2/CO ratio close to 2, i.e., the production of dimethyl ether (DME), methanol, Fischer-Tropsch (F-T) Diesel (Reaction 6) (Fig. 7.6). 

There are four alternative fuels that can be relatively easily used in conventional compression ignition (Cl) engines vegetable oil, biodiesel, Fischer-Tropsch (FT), and dimethyl ether (DME). Both FT and DME can be manufactured from natural gas and are therefore not limited by feedstock availability. Biodiesel on the other hand, is produced from vegetable (and some waste animal) oils whose supply for non-nutritional uses is presently quite limited. 

Finally, an additional approach to using hydrocarbon fuels with Ni-based anodes involves using methanol and ethanol, molecules that carry sufficient oxygen to avoid carbon formation.Unlike the case with low-temperature fuel cells, methanol crossover is not an issue with ceramic membranes. Since methanol decomposes very readily to CO and H2. SOFC can operate with a very high performance using this fuel. ° ° In addition, recent work has shown promising performance levels with limited carbon deposition using dimethyl ether as fuel. ° ° ... 

Cold weather starting for ethanol fuels is poor unless blended with gasoline or some other starting fluid such as dimethyl ether or isopentane. The minimum starting temperature for neat ethanol fuel is about 60°F (15.6°F). In E95, E85, and E10 blends, the starting problems are minimized. 

Dimethyl ether has been used as an effective ignition improver for other alternative fuels such as methanol and ethanol and can be used as an aerosol propellant. Like methanol, DME can be synthesized from fossil fuel sources or from biomass. 

Dimethyl ether was first proposed as an alternative fuel for direct-injected (DI) diesel applications in 1995. Since that time, engine testing has shown DME to be as effective as CNG, LPG, and methanol in producing low levels of engine exhaust emissions. Results of an engine study completed in Austria using a Navistar V8 diesel engine are provided in TABLE 12-13. 

Ofner, H., D. W. Gill, and C. Krotscheck. 1998. Dimethyl Ether as Fuel for Cl Engines-ANew Technology and its Environmental Potential. Report No. 981158. Warrendale, Pa. Society of Automotive Engineers. 

The results of catalytic partial oxidation of methanol over the spinel catalysts derived from CoAl- and CoAISn-LDH are presented in Table 2. A methanol conversion of 30 to 50 mol % was obtained over catalyst derived from CoAI-LDH. The products obtained were H2, H20, CO and C02. Other products such as formaldehyde, methyl formate or dimethyl ether was not observed under the present experimental conditions. The selectivity of H20 was very high (= 40 to 60 %), probably because of the involvement of the complete oxidation of methanol over these catalysts. It is interesting to note from the Table that the methanol conversion rate and the selectivity of CO2 increased over the catalyst derived from the Sn-containing analogue. The observation that only traces of CO is produced in the Sn-containing catalyst, is attractive for the development of catalyst for POM reaction to produce H2 for fuel cell applications. The only inconvenience is the higher selectivity of H2O by complete oxidation, probably because of the higher Co content in the sample. 

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