Showing papers on "Syngas published in 1987"

Methanation and photo-methanation of carbon dioxide at room temperature and atmospheric pressure

Abstract: The Sabatier reaction: CO2+4H2 → CH4+2H2O(g) ΔG°298K = −27 kcal mol−1 (1) is an important catalytic process of wide industrial and academic interest1—3. It is applied to syngas conversion and the treatment of waste streams. Methane is one of the most important carbon resources of the world, serving as an energy vector as well as a feedstock for higher-value chemicals4—6. Despite its favourable thermodynamics, the eight-electron reduction of CO2 to CH4 by hydrogen is difficult to achieve: high-energy intermediates impose large kinetic barriers, and the formation of side products is common. Intensive investigations during the past decade have therefore been aimed at improving the activity and selectivity of methanation catalysts 1–3,8–11. Although significant progress has been made in this field, elevated temperatures (T>300 °C) and pressures (P> 1 atm) are still required for methane generation to proceed at significant rates and yields. Here we report the selective conversion of CO2 to methane at room temperature and atmospheric pressure, using highly dispersed Ru/RuOx loaded onto TiO2 as a catalyst. The reaction rate is sharply enhanced through photo-excitation of the support material.

On Some Problems of Selectivity in Syngas Reactions on the Group VIII Metals

Abstract: There are probably very few other systems in industrial chemistry which equal the CO/H2 reaction system in the variety of possible products. When using pure Ni or Co catalysts one can produce almost pure CH, or a mixture of saturated hydrocarbons; a promoted (K2O) iron catalyst produces, in addition to these products, also alcohols, aldehydes, and other oxygen-containing products (oxygenates); and almost pure CH3OH can be obtained when applying Cu/ZnO/Al2O3 or Pd-MgO promoted SiO2 catalysts. Some catalysts (Rh/V2O3) can lead the reaction of syngas toward C2-oxygenates, and others to a mixture of C2+-alcohols and aldehydes (Co, K, Cr, Fe multicomponent catalysts). All this is schematically shown in Fig. 1. It is a remarkable, but not unusual, situation that while the economic interest follows the order (Fig. 1) III > II > I, the fundamental knowledge on the reactions mentioned follows just the reverse order: I > II > III. Although the leading ideas for preparing selective catalysts are onIy slowly...

Process for the production of synthesis gas

Abstract: A process for producing an organic compound from a hydrocarbon containing feedstock. The feedstock is divided into two fractions. The first is subject to a primary steam reforming reaction. The reaction product is then combined with the second fraction and reacted with a free oxygen-rich gas in a secondary reforming reactor to form a synthesis gas having a ratio of between 0.80 and 1.00. The synthesis gas is then mixed with a hydrogen-rich stream, which has been separated from a purge gas from the synthesis loop, to form a final synthesis gas. The final synthesis gas is injected into a synthesis loop in which the desired organic compound is formed. The purge gas extracted from the loop is subjected to a physical separation to form a hydrogen-rich gas stream and a residual gas stream. A portion of the hydrogen-rich stream is recycled to form the final synthesis gas.

Integrated method of charge fuel pretreatment and tail gas sulfur removal in a partial oxidation process

Abstract: In the partial oxidation of a sulfur- and metal-containing carbonaceous charge fuel to produce a sulfur-containing synthesis gas and metal-containing molten slag, an integrated method of charge fuel pretreatment and Claus unit tail gas sulfur removal is provided. The process of the instant invention is advantageous over other partial oxidation processes in that: (i) a fluid, molten slag which flows easily is produced, thereby improving reactor performance; and (ii) the overall removal of sulfur compounds from the synthesis gas is made simpler, more efficient, and less costly, as the need for a conventional Claus unit tail gas sulfur removal process is eliminated.

Process for upgrading water used in cooling and cleaning of raw synthesis gas

Abstract: This process relates to the upgrading of at least one stream of condensate water by removing water soluble gaseous impurities from the group consisting of HCN, COS, HCOOH, and mixtures thereof as produced in a process for the production of synthesis gas by the partial oxidation of solid carbonaceous fuel and/or liquid hydrocarbonaceous fuel. In the process, at least one internally produced condensate stream of water containing the aforesaid water soluble gaseous impurities is mixed with and vaporized into a stream of synthesis gas. The vaporized mixture is then introduced into at least one bed of catalyst where the gaseous impurities are removed by hydrolysis. The upgraded water stream is then recycled in the process for use in cooling and/or scrubbing the hot raw effluent gas stream from a partial oxidation gas generator. The condensate water streams are obtained by (i) cooling a portion of the cooled and scrubbed effluent stream of synthesis gas to below the dew point temperature; and/or (ii) cooling and flashing a portion of the quench water used to quench cool and clean the hot raw effluent stream of synthesis gas thereby producing a gaseous mixture comprising H 2 O, HCN, COS, HCOOH, and mixtures thereof and cooling said gaseous mixture to condense out and separate condensed water containing said water soluble gaseous impurities.

Methanation of carbon monoxide and carbon dioxide over nickel catalyst under the transient state

Abstract: The kinetics of methanation of CO and CO2 were markedly different in the transient state. The hydrogenation of surface carbon species was strongly inhibited by reversibly adsorbed CO in the former reaction. CO2 did not inhibit the latter reaction and H2O was found to form by two distinct steps.

Recovery of nitrogen, hydrogen and carbon dioxide from hydrocarbon reformate

Abstract: Multi-column pressure swing adsorption process for simultaneous production of ammonia synthesis gas and carbon dioxide from a reformer off gas having hydrogen, nitrogen and carbon dioxide as major components accompanied by minor quantities of methane, carbon monoxide and argon as impurities. The PSA system features two groups of adsorbent columns in which CO2 is adsorbed in adsorbers of the first group, the essentially CO2 -freed effluent being charged to an adsorber of the second group for removal of minor impurities while discharging an effluent gas having an H2 /N2 content stoichiometric for NH3 synthesis. The CO2 recovered from the first group of adsorbers is available at a high purity for reaction with the ammonia product for production of urea.

Process for the production of aromatic hydrocarbons incorporating by-product utilisation

Abstract: Aromatic hydrocarbons are produced from a feedstock comprising ethane and/or propane and/or butane by the steps of: (A) reacting the feedstock in the presence of a dehydrocyclodimerization catalyst to produce a product comprising aromatic hydrocarbons, hydrogen and methane, (B) separating the product of step (A) into an aromatic hydrocarbon fraction, a methane-rich gaseous fraction and a hydrogen-rich gaseous fraction, (C) feeding all or part of the methane-rich gaseous fraction separated in step (B) to a synthesis gas production unit, thereby to produce synthesis gas, and (D) contacting the synthesis gas from step (C) together with all or part of the hydrogen-rich gaseous fraction separated in step (B), thereby increasing the hydrogen to carbon monoxide ratio of the synthesis gas, with a Fischer-Tropsch conversion catalyst to produce a hydrocarbon product.

Performance of dual-reactor system for conversion of syngas to aromatic-containing hydrocarbons

Abstract: The product stream from the synthesis gas reaction over cobalt-nickel-zirconia catalyst (FT catalyst) was modified by HZSM-5 zeolite in a dual-microreactor system at 101.3 kPa and H/sub 2//CO = 1. The effect of operating conditions on steady-state product distribution was investigated by varying the HZSM-5/FT ratio and the HZSM-5 reactor temperature. The aromatics selectivity in total hydrocarbons increases significantly either by increasing the temperature of the HZSM-5 reactor or by increasing the HZSM-5/FT ratio from 1 to 4, when the temperature of the HZSM-5 reactor is maintained below 300/sup 0/C. At higher temperatures, however, cracking reactions become prominent, resulting in a decrease in the selectivity of the liquid hydrocarbons and aromatics.

In-situ reduction of a methanol synthesis catalyst in a three-phase slurry reactor

Abstract: In the liquid phase methanol synthesis process, syngas reacts in the presence.of fine catalyst particles slurried in the oil phase, in a three phase slurry reactor system. A method for activating high concentration ( ⩽25 wt. %) of the CuO-ZnO-Al2O3 catalyst in the catalyst-oil slurry has been successfully developed. This catalyst activation process can be of crucial significance in the research and development of the methanol synthesis process in a liquid entrained reactor. The reducing gas contains 2% hydrogen in nitrogen mixture and this activation procedure is carried out at a pressure of 125 psi. The catalyst-oil slurry is subjected to a controlled temperature ramping from 110° to 250° C. The catalyst has beemshown to be effectively reduced after following this activation procedure, that is valid especially for high catalyst loadings in slurry. Since the reduction is carried out in the process liquid medium and inside the reactor system, the catalyst-oil slurry after the treatment is ready fo...

Activation and promotion studies in a mixed slurry reactor with an iron-manganese Fischer-Tropsch catalyst

Abstract: Synthesis gas was reacted over a coprecipitated iron-manganese Fischer-Tropsch catalyst in a slurry reactor. The effect of various activation parameters - temperature, pressure, and gas composition - on subsequent catalyst activity and product selectivity was investigated. The gas composition had the most dramatic effect on the catalyst activation and the ensuing synthesis gas conversion. The effect of potassium promotion on catalyst activity and product selectivity was also studied in slurry reactor tests.

Purification of ammonia syngas

Abstract: Crude ammonia synthesis gas is obtained by primary steam reforming of a hydrocarbon gas mixture rich in methane, such as natural gas, followed by secondary reforming of the primary reformate with added air and shift conversion of the contained CO to CO 2 . The shift conversion product is first freed of contained CO 2 by selective absorption in a novel PSA unit having an integrated B section for removal of remaining impurities such as carbon monoxide and methane, thereby providing as product a gas stream comprised of hydrogen and nitrogen in approximate 3:1 molar ratio accompanied by a small amount or argon derived from the air stream used in the secondary reforming step. Alternative embodiments are disclosed for removal of CO from the gas stream, before its entry into the NH 3 conversion operation; any residual CO that might have slipped thorugh the absorbent bed of the B section is converted to CH 4 .

Liquid phase methanol reactor staging process for the production of methanol

Abstract: The present invention is a process for the production of methanol from a syngas feed containing carbon monoxide, carbon dioxide and hydrogen. Basically, the process is the combination of two liquid phase methanol reactors into a staging process, such that each reactor is operated to favor a particular reaction mechanism. In the first reactor, the operation is controlled to favor the hydrogenation of carbon monoxide, and in the second reactor, the operation is controlled so as to favor the hydrogenation of carbon dioxide. This staging process results in substantial increases in methanol yield.

High temperature desulfurization of synthesis gas

Abstract: Synthesis gas, fuel gas, or reducing gas is produced by the noncatalytic partial oxidation of a sulfur-containing liquid hydrocarbonaceous fuel or a slurry of sulfur-containing solid carbonaceous fuel with a free-oxygen containing gas in a first free-flow reaction zone R 1 located in a refractory lined gas generator at an autogenous temperature in the range of about 190° F. to 2900° F. and above the ash-fusion temperature of the slag formed in the reaction zone. About 85 to 99 weight percent of the carbon in the fuel feed to the reaction zone is converted into carbon oxides. At least a portion of the hot effluent gas stream from the first reaction zone is passed through a free-flow second reaction zone R 2 in admixture with a second portion of sulfur-containing fuel and a calcium-containing additive. An equilibrium oxygen concentration with a partial pressure which is less than about 10 -12 atmosphere is provided in the gas phase in the first and second reaction zones. In the second reaction zone the carbon in the second portion of fuel, unconverted fuel and particulate matter from R 1 react with H 2 O and/or CO.sub. 2 to produce supplemental H 2 and/or carbon oxides. Further, at least a portion of the sulfur-containing gases produced in R 1 and R 2 e.g. H 2 S and COS react at high temperature with the calcium-containing additive to produce particulate matter comprising calcium sulfide. Further, a portion of this newly formed particulate matter and/or the calcium-containing additive combine with slag and/or ash in the hot raw gas stream passing through the second gas cooler. Fly-ash is produced thereby having an increased ash softening temperature. The gas stream discharged from the second reaction zone contains a reduced amount of sulfur-containing gases, and increased amounts of H 2 + carbon oxides and calcium sulfide-containing particulate matter.

Liquid carbon dioxide recovery from gas mixtures with methane

Abstract: LIQUID CARBON DIOXIDE RECOVERY FROM GAS MIXTURES WITH METHANE A B S T R A C T Land-fill and other gases containing principally methane and carbon dioxide have been separated into high BTU fuel gas and discard carbon dioxide containing apprec-iable methane Such discard gas can now be simply frac-tionated into high-purity liquid carbon dioxide with re-coveries in excess of 80% while using a single refrigerant at a single low temperature to satisfy all refrigeration requirements of fractionation This novel fractionation is ideally combined with the process of separating land-fill gas into high BTU fuel gas because then the methane and carbon dioxide are recovered completely as two valuable products, high BTU fuel gas and pure liquid carbon dioxide

Process for the pyrolytic oxidation of methane to higher molecular weight hydrocarbons and synthesis gas

Abstract: A process is disclosed for catalytically converting methane to synthesis gas and one or more saturated or unsaturated higher molecular weight hydrocarbons, such as ethane, ethylene, and acetylene. The process employs a homogeneous gas phase hydrogen halide catalyst other than hydrogen fluoride to faciltiate the pyrolytic oxidation of methane. Alternatively the homogeneous gas phase catalyst may consist of a mixture of gaseous hydrogen halide and gaseous halogen, or a halogen gas.

Cobalt catalysts, and use thereof for the conversion of methanol and for Fischer-Tropsch synthesis, to produce hydrocarbons

Abstract: A zirconium, hafnium, cerium or uranium promoted cobalt catalyst and process for the conversion of methanol or synthesis gas to hydrocarbons. Methanol is contacted, preferably with added hydrogen, over said catalyst, or synthesis gas is contacted over said catalyst to produce, at reaction conditions, an admixture of C10 + linear paraffins and olefins. These hydrocarbons can be further refined to high quality middle distillate fuels, and other valuable products such as mogas, diesel fuel, and jet fuel, particularly premium middle distillate fuels of carbon number ranging to about C20.

Process to recover hydrogen-free higher boiling synthesis gas component

Abstract: A process to recover higher boiling synthesis gas component substantially free of hydrogen comprising partial condensation of a synthesis gas reaction stream, defined stripping of hydrogen out of the resulting liquid, and fractional distillation of the resulting fluid.

Process for producing synthesis gas by partial oxidation of coal-water suspensions

Abstract: The present invention describes a process for producing synthesis gas by partial oxidation of carbon-containing particles suspended in water with oxygen at elevated pressures and temperatures of 1000° to 1600° C. Three substance streams are added separately but simultaneously to the reactor. The inner substance stream consists of oxygen or a mixture of oxygen and synthesis gas. The middle substance stream forms a carbon-water suspension, and the outer substance stream carries oxygen or oxygen-containing gases. Due to the fact that these three substance streams intersect at an acute angle, an ideal distribution of the suspension with the gas streams is achieved and an optimum reaction course is ensured. In order to be able to compensate requirement fluctuations during continuous operation, the outlet opening for the carbon-water suspension and the outer gas stream can be correspondingly adapted in a continuous and independent manner.

Process for synthesizing ammonia

Abstract: Means are disclosed for lowering the temperature of the gaseous effluent from the first catalyst bed in a continuous ammonia synthesis process in which a syngas mixture containing nitrogen and hydrogen is passed sequentially over two or more catalyst beds containing ammonia synthesis catalyst. This cooling, effected to promote the exothermic ammonia-forming reaction, is accomplished by subjecting the gaseous effluent from the first catalyst bed to heat exchange in a high temperature heat sink, preferably after having undergone heat exchange with the synthesis gas feed to the first catalyst bed, to control the temperature of the effluent entering the second catalyst bed to a desired level.

Syngas conversion catalyst

Abstract: A composition for use after reductive activation as a catalyst in the conversion of synthesis gas to hydrocarbons, which composition comprises as essential components (i) cobalt either as the elemental metal, the oxide or a compound thermally decomposable to the elemental metal and/or oxide and (ii) zinc in the form of the oxide or a compound thermally decomposable to the oxide.