Fuel dimethyl ether, synthesis

Moreover, lignocellulose is not edible and could theoretically be utilized without any impact on food production. The cellulose and hemicellulose fraction of lignocellulose may serve for the production of cellulosic ethanol, which could be produced via acid or enzymatic catalyzed hydrolysis of cellulose, followed by further fermentation to yield ethanol. Alternatively, the whole plant can be gasified to yield syngas, followed by methanol or dimethyl ether synthesis or Fischer-Tropsch technology that produces hydrocarbon fuels. Furthermore, controlled (bio-)chemical transformations to novel fuel compounds based on cellulose, hemicellulose, or lignin are possible, and numerous recent publications emphasize intense research in this direction. 

Adachi, Y., Komoto, M., Watanabe, I., Ohno, Y., and Fujimoto, K. Effective utilization of remote coal through dimethyl ether synthesis. Fuel, 2000, 79, 229. 

In Fig. 5.28a experimental and simulated rates for the synthesis of MTBE from methanol and isobutene are depicted, which show that the rate expression (5.63) is valid for the MTBE synthesis [45]. Fig. 5.28b illustrates its validity for the ETBE synthesis from ethanol and isobutene [41] compared with experimental data reported by Francoisse and Thyrion [47]. In analogous manner this rate approach can be applied to the synthesis of the fuel ether TAME from methanol and isoam-lyenes [43, 46]. Activity-based rate expressions were also applied for other reactions carried out in strongly non-ideal liquid mixtures, for example for butyl acetate synthesis [48] and for dimethyl ether synthesis [49]. 

The data produced were instrumental in establishing a proper phenomenological model for the bubble column. This model was able to predict both liquid and gas tracer curves obtained in an AFDU pilot-plant column in LaPorte, Texas, for three different reaction systems methanol synthesis, dimethyl ether synthesis, and Fischer Tropsch synthesis (Chen et ah, 1998 Devanathan et ah, 1990 Gupta et al., 2001a, 2001b). Unfortunately, the desire to use improved science in scale-up gas-to-Hquid fuels processes to large diameter bubble columns disappeared when Hquefaction of natural gas became more economically attractive. 

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 ... 

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. 

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). 

Sardesai, A. Tartamella, T. Lee, S. Synthesis of hydrocarbons from dimethyl ether selectivities toward light hydrocarbons. Fuel Sci. Technol. Int. 1996, 14 (5), 703-712. 

AI3-16096 Anesthenyi Bis(methoxy)methane Dimeth-oxymethane Dimethyl formal 2,4-Dioxapentane EINECS 203-714-2 Formal Formaldehyde dimethyl-acetal Formaldehyde methyl ketal HSDB 1820 Methane, dimethoxy- Methoxymethyl methyl ether Methylal Methylene dimethyl ether Metylal UN1234, Used as a solvent In organio synthesis perfumes, adhesives, protective coatings special fuel. Liquid mp = -104.8° bp = 42° d = 0.8593 soluble in H2O (30 g/100 ml), very soluble In EtOH, Et20, MezCO, CeHe LD50 (rbt orl) n5708mg/kg. 

Example 8.2 Dimethyl ether (DME) has long been touted by several researchers as an alternative fuel for transportation, largely due to is similarities to current fuels and its favorable environmental properties. One method of DME synthesis is to transform raw feeds such as coal or natural gas to methanol (MeOH), which can in turn be converted to DME via the following reaction ... 

Currently, the attention is focused on the synthesis of both liquid biofuels - mainly FT-diesel products and methanol - and gaseous synthetic fuels such as dimethyl ether (DME) and substitute natural gas (SNG, which is addressed in this chapter) the main parameters (pressure, temperature, type of catalyst, H2/CO ratio) governing the different synthesis pathways of these fuels are reported in reference [4],... 

Dimethyl ether is used as a solvent in aerosol formulations. Diethyl ether as a commercial product is available in several grades and is used as an extraction solvent, reaction solvent, and as a general anesthetic. Ethyl ether is an excellent solvent for alkaloids, dyes, fats, gums, oils, resins, and waxes. Blends of ethyl ether and ethanol are excellent solvents for cellulose nitrate used in the manufacture of guncotton, in collodion solutions and pyroxylin plastics. Ethyl ether is used in the recovery of acetic acid from aqueous solutions in the cellulose acetate and plastic industry. It is used as a starter fuel for diesel engines and as a denaturant in denatured ethanol formulations. Grignard and Wurtz-Fillig synthesis reactions use diethyl ether as an anhydrous, inert reaction medium. 

Hydrogen is essential in the hydro-treatment processes used in refineries, or in complex bio-refineries, for the production of high-quality fuels with low environmental impact (e.g. desulfiirizafion and intense dearomatization) and for the eonversion of heavy crude oil and hy-products into middle distillates. The importance of H2 is also well known in petroehemistry (the synthesis of methanol, dimethyl ether, ammonia or hydrocarbons via Fischer-Tropsch). It also has potential as an energy vector for its clean fuel eharacterisfies. 

The reaction shown is an oversimplification and items such as shifting the equilibrium toward methanol, catalyst poisoning, and pressure/temperature tradeoffs need to be considered and are the subject of a text [3]. Methanol has many uses as a solvent and is the major component of windshield washer fluid. However, most methanol is converted to other commodity chemicals such as acetic acid, formaldehyde, or dimethyl terephthalate. It can also be used directly as a fuel additive, as a component in the synthesis of biodiesel or converted to dimethyl ether or methyl-t-butyl ether (MTBE), two fuel additives. 

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