Hydrocarbons production from methanol

Slurry bubble column reactor for methanol and other hydrocarbons productions from synthesis gas is an issue of interest to the energy industries throughout the world. Computational fluid dynamics (CFD) is a recently developed tool which can help in the scale up. We have developed an algorithm for computing the optimum process of fluidized bed reactors. The mathematical technique can be applied to gas solid, liquid-solid, and gas-liquid-solid fluidized bed reactors, as well as the LaPorte slurry bubble column reactor. Our computations for the optimum particle size show that there is a factor of about two differences between 20 and 60 pm size with maximum granular-like temperature (turbulent kinetic energy) near the 60 pm size particles. 

Copper-containing mordenite catalysts have also been reported to be active for carbonylation of vapor-phase methanol [170]. Initially, the predominant reaction products were hydrocarbons resulting from methanol-to-gasoline chemistry, but after about 6 h on stream at 350 °C the selectivity of the catalyst changed to give acetic acid as the main product. A recent investigation was carried out with in situ IR and solid-state NMR spectroscopies to probe the mechanism by detecting surface-bound species. The rate of carbonylation was found to be enhanced by the presence of copper sites (compared to the metal-free system), and formation of methyl acetate was favored by preferential adsorption of CO and dimethyl ether on copper sites [171],... 

Hydrogen Production from Methanol to Heavy Hydrocarbons 425... 

In the beginning of 90th, Tan and Davis [136] investigated the coreaction of ethylene and methanol over silicalite S-115 by the isotopic tracer method ( "C labeled or unlabeled methanol and unlabeled or labeled ethylene) and concluded that ethylene was converted by adding a Cj specie derived from methanol. However, the relative "C in the hydrocarbon products revealed that the alkylation of alkenes is more rapid than the formation of Cj" and alkenes from methanol oidy. For the conversion of ethylene only (in the absence of MeOH), the dimerization to form butenes was the dominant reaction. Adding a flow of water in an amount equimolar to ethylene significantly decreased the conversion of ethylene. The addition of methanol to the feed stream, in an amount equal to that of ethylene, increased the total conversion and altered the product distribution so that propylene is formed in about twice the amount of butenes. The labels on the C3-C5 number products were similar to that of ethylene. The authors concluded therefore that the C3-C5 products were formed by the successive addition of an unlabeled Cj species derived from methanol to labeled ethylene. The data clearly show that the formation of ethylene from methanol is a slow reaction compared to the addition of the Cj species to the products. Thus, the formation of ethylene is an important issue only for the reaction initiation. In those processes, where a small amount of alkenes are added to the methanol feed, the formation of ethylene directly from methanol represents a small part of the hydrocarbons produced from methanol. 

Hutchings GJ, Hunter R. Hydrocarbon formation from methanol and dimethyl ether a review of the experimental observations concerning the mechanism of formation of the primary products. Catal Today 1990 6 279-306. 

Commercial production of acetic acid has been revolutionized in the decade 1978—1988. Butane—naphtha Hquid-phase catalytic oxidation has declined precipitously as methanol [67-56-1] or methyl acetate [79-20-9] carbonylation has become the technology of choice in the world market. By-product acetic acid recovery in other hydrocarbon oxidations, eg, in xylene oxidation to terephthaUc acid and propylene conversion to acryflc acid, has also grown. Production from synthesis gas is increasing and the development of alternative raw materials is under serious consideration following widespread dislocations in the cost of raw material (see Chemurgy). 

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. 

Synthesis gas is an important intermediate. The mixture of carbon monoxide and hydrogen is used for producing methanol. It is also used to synthesize a wide variety of hydrocarbons ranging from gases to naphtha to gas oil using Fischer Tropsch technology. This process may offer an alternative future route for obtaining olefins and chemicals. The hydroformylation reaction (Oxo synthesis) is based on the reaction of synthesis gas with olefins for the production of Oxo aldehydes and alcohols (Chapters 5, 7, and 8). 

A recent development, which could lead to a reassessment of the Fischer-Tropsch reaction as a route to gasoline range product, is the announcement by Mobil of a direct route from methanol to hydrocarbons and water (101) ... 

The liquid hydrocarbon yield from the BTL production via gasification and FT synthesis is about 42% based on the LHV, which is similar to the production of BTL via gasification, methanol synthesis and the MtSynfuel process (Dena, 2006). 

In addition to the direct use of ethanol as a fuel, its use as a source of H2 to be used with high efficiency in fuel cells has been thoroughly investigated. H2 production from ethanol has advantages compared vdth other H2 production techniques, including steam reforming of hydrocarbons and methanol. Unlike hydrocarbons, ethanol is easier to reform and is also free of sulfur, which is a well-known catalyst poison. Furthermore, unlike methanol, ethanol is completely renewable and has lower toxicity. 

According to another important and promising technology, hydrocarbons are produced from methanol, which, in turn, is synthesized from synthesis gas. Called the methanol-to-gasoline process, it was practiced on a commercial scale and its practical feasibility was demonstrated. Alternative routes to eliminate the costly step of synthesis gas production may use direct methane conversion through intermediate monosubstituted methane derivatives. An economic evaluation of different methane transformation processes can be found in a 1993 review.1... 

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