Synthesis gas mixtures

During the late seventies and early eighties, when oil prices rose after the 1973 war, extensive research was done to change coal to liquid hydrocarbons. However, coal-derived hydrocarbons were more expensive than crude oils. Another way to use coal is through gasification to a fuel gas mixture of CO and H2 (medium Btu gas). This gas mixture could be used as a fuel or as a synthesis gas mixture for the production of fuels and chemicals via a Fischer Tropsch synthesis route. This process is... 

Fischer Tropsch technology is best exemplified by the SASOL projects in South Africa. After coal is gasified to a synthesis gas mixture, it is purified in a rectisol unit. The purified gas mixture is reacted in a synthol unit over an iron-based catalyst. The main products are gasoline, diesel fuel, and jet fuels. By-products are ethylene, propylene, alpha olefins, sulfur, phenol, and ammonia which are used for the production of downstream chemicals. 

As mentioned in Chapter 2, methane is a one-carhon paraffinic hydrocarbon that is not very reactive under normal conditions. Only a few chemicals can he produced directly from methane under relatively severe conditions. Chlorination of methane is only possible by thermal or photochemical initiation. Methane can be partially oxidized with a limited amount of oxygen or in presence of steam to a synthesis gas mixture. Many chemicals can be produced from methane via the more reactive synthesis gas mixture. Synthesis gas is the precursor for two major chemicals, ammonia and methanol. Both compounds are the hosts for many important petrochemical products. Figure 5-1 shows the important chemicals based on methane, synthesis gas, methanol, and ammonia. ... 

A few chemicals are based on the direct reaction of methane with other reagents. These are carbon disulfide, hydrogen cyanide chloromethanes, and synthesis gas mixture. Currently, a redox fuel cell based on methane is being developed. ... 

Many chemicals are produced from synthesis gas. This is a consequence of the high reactivity associated with hydrogen and carhon monoxide gases, the two constituents of synthesis gas. The reactivity of this mixture was demonstrated during World War II, when it was used to produce alternative hydrocarbon fuels using Fischer Tropsch technology. The synthesis gas mixture was produced then hy gasifying coal. Fischer Tropsch synthesis of hydrocarbons is discussed in Chapter 4. 

Ethylene glycol could he produced directly from synthesis gas using an Rh catalyst at 230°C at very high pressure (3,400 atm). In theory, five moles synthesis gas mixture are needed to produce one mole ethylene glycol ... 

In addition to being major sources of hydrocarbon-based petrochemicals, crude oils and natural gases are precursors of a special group of compounds or mixtures that are classified as nonhydrocarbon intermediates. Among these are the synthesis gas mixture, hydrogen, sulfur, and carbon black. These materials are of great economic importance and are discussed in Chapter 4. 

On the basis of this past work and ongoing experiments, we feel that the liquid-phase methanation process promises to become an economic, reliable, and versatile means of converting synthesis gas mixtures to high Btu gas. Chem Systems believes that this technology is a key step in the transformation of fossil feeds into pipeline gas, and we look forward to its successful application in commercial coal gasification plants. 

CO in the synthesis gas mixture for the methanol synthesis does not seem to take part directly in the reaction, but it does influence the process through two effects First the water-gas shift reaction and, secondly, through its effect on the surface morphology (and possibly also composition). For thermodynamic reasons, however, it would be desirable if CO could be hydrogenated directly via Eq (18) instead of going through two coupled equations (3) and (19), since it would yield a higher equilibrium concentration of methanol at the reactor exit. 

C30 oil, homopolymer of 1-decene, Ethyl Corp., Inc.) served as the start-up solvent for the experiments. The catalyst (ca. 5-8 g) was added to start-up solvent (ca. 300 g) in the CSTR. The reactor temperature was then raised to 270°C at a rate of l°C/min. The catalyst was activated using CO at a space velocity of 3.0 sl/h/g Fe at 270°C and 175 psig for 24 h. FTS was then started by adding synthesis gas mixture (H2 CO ratio of 0.7) to the reactor at a space velocity of either 3.1 or 5.0 sl/h/g Fe. The conversions of CO and H2 were obtained by gas chromatography (GC) analysis (HP Quad Series Micro-GC equipped with thermal conductivity detectors) of the product gas mixture. The reaction products were collected in three traps maintained at different temperatures—a hot trap (200°C), a warm trap (100°C), and a cold trap (0°C). The products were separated into different fractions (rewax, wax, oil, and aqueous) for quantification by GC analysis. However, the oil and the wax (liquid at room temperature) fractions were mixed prior to GC analysis. 

The catalytic activation of carbon monoxide is a research area currently receiving major attention from academic, industrial, and government laboratories. There has been a long standing interest in this area however, the new attention obviously is stimulated by concerns with the present and future costs and availability of petroleum as a feedstock for the production of hydrocarbon fuels and of organic chemicals. One logical alternative source to be considered is synthesis gas, mixtures of carbon monoxide and hydrogen that can be produced from coal and other carbonaceous materials. 

Synthesis gas generation routes, for methanol, 16 302-307 Synthesis gas mixture ( syngas ), 73 842, See also Syngas plants Synthesis loop, methanol, 16 307... 

The presence of water in synthesis gas mixtures along with light components, such as carbon monoxide or hydrogen, has the effect that phase separations may persist even under extreme conditions of temperature and pressure. The need exists to demonstrate that these phase separations, perhaps with simultaneous reaction equilibrium, can be described by models capable of some accuracy. 

Since synthesis gas mixtures are capable of showing more than one critical point, there is a possibility of finding more than one solution to the simultaneous equations defining reaction equilibria and the critical point. This possibility was not encountered in the present study. 

At the Mellon Institute he applied l4C tracers to examine the behavior of intermediates in Fischer-Tropsch synthesis over iron catalysts. By adding small amounts of radioactively labeled compounds to the CO/H2 synthesis gas mixtures, he was able to prove that some of these compounds (e.g., small alcohols) are involved in the initiation step of the chain growth process that leads to larger hydrocarbon products. It was during this era that his associates first placed a catalytic reactor into the carrier gas stream of a gas chromatograph and developed the microcatalytic pulse reactor, which is now a standard piece of equipment for mechanistic studies with labeled molecules. While at Mellon Institute Emmett began editing his comprehensive set of seven volumes called Catalysis, which he continued at Hopkins. 

The dew point must be warmer than -56.6°C to permit use of liquid carbon dioxide absorbent because pure liquid carbon dioxide cannot exist below the triple point. The carbon dioxide partial pressure, i.e., gas phase CO2 mol fraction times total pressure, of synthesis gas mixtures with -56.6°C dew points is plotted versus synthesis gas pressure in Figure 4. Increasing the H2 CO ratio at fixed total pressure decreases the carbon dioxide partial pressure required for a -56.6°C dew point. Liquid carbon dioxide can be used to absorb sulfur molecules for any combination of gas pressure and carbon dioxide partial pressure which lies above the curves of Figure 4. 

Future widespread use of anthropogenic C02 in combination with renewable hydrogen as well as the implementation of coal, biomass, and other nonconventional sources of synthesis gas will lead to suboptimal synthesis gas compositions. Efficient incorporation of these synthesis gas mixtures into the current methanol synthesis infrastructure will necessitate the redevelopment of catalysts to perform stably under high concentrations of C02, water, and impurities. To that end, advanced characterization methods must be implemented to discriminate between surface area loss by... 

Molecular hydrogen can be used as a reducing agent in the presence of CO the equimolar CO/H2 synthesis gas mixture is employed to reduce metal carboxylates (equation 7). Metal alkyls or aryls, such as Grignard reagents (see Grignard Reagents), lithium alkyls or aryls, and aluminum alkyls, have... 

This combined synthesis gas mixture is stoichiometric for methanol synthesis ... 

Fuderer, A. Selective adsorption process for production of ammonia synthesis gas mixtures. U.S. Patent 4,375,363, 1983. 

Several packed bed reactors are employed by the petroleum refining industries utilizing natural gas as feedstock. Different compositions of synthesis gas (mixtures of carbon monoxide and hydrogen) or syngas are important... 

A 125 mL Parr Monel bomb was charged with 0.02 mmol of the Pt polymer-supported catalyst I and 0.04 mmol of stannous chloride dihydrate. The bomb was brought into an argon-filled glove bag and charged with 8.7 mmol of norbor-nene dissolved in 3 mL of benzene. The bomb was sealed, pressurized, and vented three times with the synthesis gas mixture (1 1 COiHa) and then pressurized to 2700 psi and heated with stirring in an oil bath at 60° for 4 hours. At the end of the reaction, the bomb was opened in a glove bag. Catalyst I was recovered by filtration. The reaction mixture was analyzed by GC to determine the conversion (100%) and the aldehyde selectivity (87%). H NMR of the mixture in the presence of Eu(hfc)3 determined that the exo-norbornanecarboxaldehyde was obtained in 20% ee. 

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