Gas conversion

Dimethyl Ether. Synthesis gas conversion to methanol is limited by equiUbrium. One way to increase conversion of synthesis gas is to remove product methanol from the equiUbrium as it is formed. Air Products and others have developed a process that accomplishes this objective by dehydration of methanol to dimethyl ether [115-10-6]. Testing by Air Products at the pilot faciUty in LaPorte has demonstrated a 40% improvement in conversion. The reaction is similar to the Hquid-phase methanol process except that a soHd acid dehydration catalyst is added to the copper-based methanol catalyst slurried in an inert hydrocarbon Hquid (26). 

The recorded chronology of the coal-to-gas conversion technology began in 1670 when a clergyman, John Clayton, in Wakefield, Yorkshire, produced in the laboratory a luminous gas by destmctive distillation of coal (12). At the same time, experiments were also underway elsewhere to carbonize coal to produce coke, but the process was not practical on any significant scale until 1730 (12). In 1792, coal was distilled in an iron retort by a Scottish engineer, who used the by-product gas to illuminate his home (13). 

The chemistry of the oil-to-gas conversion has been estabUshed for several decades and can be described in general terms although the primary and secondary reactions can be truly complex (5). The composition of the gases produced from a wide variety of feedstocks depends not only on the severity of cracking but often to an equal or lesser extent on the feedstock type (5,62,63). In general terms, gas heating values are on the order of 30—50 MJ/m (950-1350 Btu/fT). 

A similar process to SMDS using an improved catalyst is under development by Norway s state oil company, den norske state oHjeselskap AS (Statod) (46). High synthesis gas conversion per pass and high selectivity to wax are claimed. The process has been studied in bubble columns and a demonstration plant is planned. 

Direct conversion of natural gas to Hquids has been actively researched. Process economics are highly variable and it is unclear whether direct natural gas conversion technologies are competitive with the estabUshed indirect processes. Some emerging technologies in this area are presented herein. 

The Fischer-Tropsch reaction is highly exothermic. Therefore, adequate heat removal is critical. High temperatures residt in high yields of methane, as well as coking and sintering of the catalyst. Three types of reac tors (tubular fixed bed, fluidized bed, and slurry) provide good temperature control, and all three types are being used for synthesis gas conversion. The first plants used tubular or plate-type fixed-bed reactors. Later, SASOL, in South Africa, used fluidized-bed reactors, and most recently, slurry reactors have come into use. 

Status of Indirect Liquefaction Technology The only commercial indirect coal liquefaction plants for the production of transportation fuels are operated by SASOL in South Africa. Construction of the original plant was begun in 1950, and operations began in 1955. This plant employs both fixed-bed (Arge) and entrained-bed (Synthol) reactors. Two additional plants were later constructed with start-ups in 1980 and 1983. These latter plants employ dry-ash Lurgi Mark IV coal gasifiers and entrained-bed (Synthol) reactors for synthesis gas conversion. These plants currently produce 45 percent of South Africa s transportation fuel requirements, and, in addition, they produce more than 120 other products from coal. 

Coproduction of electricity along with synthesis gas conversion offers the potential for significant cost savings. The once-through liquid-phase methanol technology was developed specifically for this... 

SOURCE Ftoc. Coal Liquefaction and Gas Conversion Contractors Review Conf, CONF-9508133, Pittsburgh Energy Technology Center, Pittsburgh, Pa., 1995. 

Volume 61 Natural Gas Conversion. Proceedings of the Symposium on Natural Gas Conversion, Oslo, August 12-17,1990 edited by A. Holmen, K.-J. Jens and S. Kolboe Volume 62 Characterization of Porous Solids II. Proceedings of the lUPAC Symposium (COPS II), Alicante, May 6-9,1990... 

Volume 81 Natural Gas Conversion II. Proceedings of the Third Natural Gas Conversion Symposium, Sydney, July 4-9,1993 edited by H.E. Curry-Hyde and R.F. Howe... 

Proceedings of the 1st International Symposium/6th European Workshop, Oostende, Belgium, February 17-19,1997 edited by G.F. Froment, B. Delmon and P. Grange Volume 107 Natural Gas Conversion IV... 

Proceedings of the 5th International Gas Conversion Symposium, Giardini-Naxos, Taormina, Italy, September 20-25,1998... 

The coal conversion efficiency to synthetic, pipeline-cjuality natural gas or licjtiid crude oil is in the 60 to 70 percent range. This means that only 60 to 70 percent of the latent heat energy in the coal can be obtained by burning the product of the conversion. However, for the lower Btu per cubic foot products of water gas and coke oven gas, conversion efficiencies can reach over 95 percent. 

In the following we will concentrate on three important cases, i.e. CO oxidation on alkali doped Pt, ethylene epoxidation on promoted Ag and synthesis gas conversion on transition metals. We will attempt to rationalize the observed kinetic behaviour on the basis of the above simple rules. 

Volume 61 Natural Gas Conversion. Proceedings of the Symposium on Natural Gas... 

Volume 81 Natural Gas Conversion II. Proceedings of the Third Natural Gas Conversion... 

Proceedings of the S"" International Gas Conversion Symposium, Giardini-Naxos, Taormina, Italy, September 20-25, 1998 edited by A. Parmaliana, D. Sanlilippo, F. Frusteri, A.Vaccari and F.Arena Volume 120A Adsorption and its Applications in Industry and Environmental Protection. 

Proceedings of the 6" Natural Gas Conversion Symposium. June 17-22, 2001, Alaska, USA. 

Proceedings of the 7" Natural Gas Conversion Symposium, Dalian, China, June 6-10, 2004... 

Assuming plug flow of both phases in the trickle bed, a volumetric mass transfer coefficient, kL a, was calculated from the measurements. The same plug flow model was then used to estimate bed depth necessary for 95% S02 removal from the simulated stack gas. Conversion to sulfuric acid was handled in the same way, by calculating an apparent first-order rate constant and then estimating conversion to acid at the bed depth needed for 95% S02 removal. Pressure drop was predicted for this bed depth by multiplying... 

Proceedings of the 4th International Natural Gas Conversion Symposium, Kruger Park, South Africa, November 19-23, 1995... 

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