Methanol mixed synthesis gases

Two major versions of the MTG process currently exist. The first, as exemplified by the New Zealand GTG configuration, is a fixed-bed process the second is a fluidized-bed process. A third process concept, the Topsoe TIGAS [40], integrates methanol synthesis with MTG. This variation uses a multifunctional catalyst for producing a mixed oxygenate feed (including methanol) from synthesis gas and was tested... 

Quench Converter. The quench converter (Fig. 7a) was the basis for the initial ICl low pressure methanol flow sheet. A portion of the mixed synthesis and recycle gas bypasses the loop interchanger, which provides the quench fractions for the iatermediate catalyst beds. The remaining feed gas is heated to the inlet temperature of the first bed. Because the beds are adiabatic, the feed gas temperature increases as the exothermic synthesis reactions proceed. The injection of quench gas between the beds serves to cool the reacting mixture and add more reactants prior to entering the next catalyst bed. Quench converters typically contain three to six catalyst beds with a gas distributor in between each bed for injecting the quench gas. A variety of gas mixing and distribution devices are employed which characterize the proprietary converter designs. 

Retrofitting features of the more efficient reactor types have been the principal thmst of older methanol plant modernization (17). Conversion of quench converters to radial flow improves mixing and distribution, while reducing pressure drop. Installing an additional converter on the synthesis loop purge or before the final stage of the synthesis gas compressor has been proposed as a debotdenecking measure. 

Several other important commercial processes need to be mentioned. They are (not necessarily in the order of importance) the low pressure methanol process, using a copper-containing catalyst which was introduced in 1972 the production of acetic add from methanol over RhI catalysts, which has cornered the market the methanol-to-gasoline processes (MTG) over ZSM-5 zeolite, which opened a new route to gasoline from syngas and ammoxidation of propene over mixed-oxide catalysts. In 1962, catalytic steam reforming for the production of synthesis gas and/or hydrogen over nickel potassium alumina catalysts was commercialized. 

The use of a mixed oxygen ion-electronic conductor membrane for oxygen separation with direct reforming of methane, followed by the use of a mixed protonic-electronic membrane conductor for hydrogen extraction has also been proposed in the literature [34]. The products are thus pure hydrogen and synthesis gas with reduced hydrogen content, the latter suitable, for example, in the Fish-er-Tropsch synthesis of methanol [34]. 

A possible solution is to gasify the more dilute vacuum tower bottoms product in an oxygen blown gasifier and to convert the excess synthesis gas to methanol. In those cases where a Flexicoker is used the heavy scrubber liquids could be recycled to extinction. Therefore, the plant products are SNG, naphtha, 300-800°F distillate and methanol. All of these products are of high quality or can be hydrotreated to achieve high quality. As a result, they could be easily integrated into the utility fuel mix with a minimum amount of disruption or special product handling facilities. 

One of the most studied cases, and also the most successful, was that of hydroxycarbonate for preparing catalysts containing copper and zinc or chromium with additional elements (e g Co or Al) The reason for these studies was the practical importance of catalysts used for making synthesis gas and methanol Tabic 2 [5], which gives the composition of various precursors with their structure, suggests the mixed oxides which could be formed by decomposition Additional data can be found elsewhere [5, 23-26]... 

Low-pressure methanol synthesis relies almost exclusively on catalysts based on copper, zinc oxide, and alumina. The catalysts are produced by ICI (now Johnson Matthay), Siidchemie (now Clariant), Haldor Topsoe, in the past also by BASF, and other chemical enterprises and contain 50-70 atomic % CuO, 20%-50% ZnO, and 5%-20% Al203. Instead of alumina, chromium oxide and rare earth oxides have also been used. The mixed oxide catalysts are usually shipped as 4-6 mm cylindrical pellets with specific surface area of 60-100 m2/g. The catalysts are activated in situ with dilute hydrogen, often derived from off-gases from synthesis gas... 

Catalysts based on copper/zinc mixed oxides are of great importance for industrial scale catalytic processes like low pressure methanol formation from synthesis gas and steam reforming of methanol yielding H2 and CO2. The commercially available catalyst for both reactions is the ternary system Cu-Zn0/Al20s [5], In consequence of its success, the Cu-ZnO system has prompted a great deal of fundamental work devoted to clarify either the role played by each component and the nature of the active site. 

The most common method of making acetic acid is one developed by the Monsanto chemical corporation. In this process, synthesis gas (a mixture of carbon monoxide [CO] and hydrogen [H3]) is heated over a catalyst of copper metal mixed with zinc oxide to make methanol (methyl alcohol CH30H). The methanol is then treated with carbon monoxide (CO) to make acetic acid. Acetic acid can also be made by the fermentation of any material that contains sugar or some other carbohydrate. Although this method is of interest from a historical standpoint, it is not sufficiently efficient to use industrially. 

The synergistic effect of ruthenium and rhodium in methanol homologation was observed at 100 atm synthesis gas pressure, whereas ruthenium or rhodium chloride alone is inactive for ethanol synthesis.No enhancement of ethanol production was observed with the mixed-metal compounds [HRuRh3(CO)i2], [HRuRh3(CO)io(PPh3)2], [H2Ru2Rh2(CO),2], and [PPN][RuRh5(CO),6] as catalyst precursors. This is consistent with the cluster decomposition found to occur in all the experiments. ... 

Figure 2 shows the products obtained in a scheme in which direct upgrading of the wood pyrolysis liquids over ZSM-5 occurs in parallel with upgrading of methanol obtained from synthesis gas derived from gasification of the pyrolysis char. In Figure 3, the methanol is mixed with the pyrolysis liquids prior to co-processing over ZSM-5. Approximately 40 lbs. of methanol per 100 lbs. of dry wood feed is potentially available from the char and pyrolysis gas products. 

Until about 1930, Boyle s methanol-making method remained in use. Today, it is made from synthesis gas. When steam reacts with coal, oil, or natural gas, it forms a mix of hydrogen and carbon monoxide. This mixture is known as syngas, and it can be reacted with a zinc-oxide/chromium-oxide catalyst to make methanol. Methanol is used as a gasohne additive (it makes the gas b um better), as an industrial solvent, and, of course, as an ingredient in windshield washer fluid. 

A gas produced by high-temperature gasification of a coal slurry [2.24], for instance, and containing some 10 % CO2, 45 % CO and 36 % H2 (in addition to sulfur components and a few inerts) could be shifted without any catalysts simply by quenching with water to obtain a syngas which would be appropriate for methanol production. To this end, 0.55 kg of water would have to be added to the raw gas containing some 0.4 kg of steam per m of gas at approximately 15(X) °C. The temperature of the mix would in this way be adjusted to approximately 950°C and about one fifth of the CO in the raw gas would be converted. The converted gas would then contain 32 % CO2, 19.5 % CO and 40 % H2 so that -after the CO2 has been washed out to approximately 3 % - the methanol synthesis gas will have a stoichiometric ratio of 2.07. 

When methane or coal is used to produce synthesis gas, zeolites offer an alternative to classical Fisher-Tropsch catalysts. Indeed, when ZSM-5 or SAPO-11 is mixed with methanol synthesis catalysts, hy carbons are produced in a single step directly fi om the synthesis gas. The boiling range of the hydrocarbons produced can be narrowed and... 

Natural gas, (essentially pure methane at 1-5 MPa, 25 °C) and steam (l-5MPa, 450°C) are mixed in the ratio 4mol steam 1 mole methane and contacted with a catalyst to produce synthesis gas for a methanol convertor. The following reactions occur ... 

The idealized flow models and axial dispersion model are used extensively to predict the performance of three-phase slurry reactors. For example, mixed flow model and axial dispersion models are used to predict the reactant conversion and product distribution for conversion of synthesis gas to liquid fuels using FT synthesis [52-57], methanol synthesis... 

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