Synthesis Of Liquid Hydrocarbons Research Articles

Ultrafine Metal Powders Used as Gas to Liquids Catalysts

The paper deals with the effect of synthesis parameters on the reactivity of Fischer– Tropsch iron-based catalyst resulting from electrical wire explosion in a carbon monoxide medium. The technology provides the synthesis of ultrafine particles with a large specific surface area and a given phase composition. A mixture resulting from the synthesis of liquid hydrocarbons contains hydrocarbons of a paraffinic and aromatic structure, and its further use requires additional refinement.

Effect of the Type of the Cobalt-Containing Component of a Composite Catalyst on the One-Stage Synthesis of Liquid Hydrocarbons from СО and Н2

The effect of the type of the cobalt-containing component (Со-Al2O3/SiO2, Co-Re/Al2O3, and Co-Re/TiO2) of a composite catalyst on the combined synthesis and hydroconversion of hydrocarbons by the Fischer–Tropsch process are investigated. The catalytic properties of catalyst samples are studied in a flow reactor with a fixed catalyst layer at 2 MPa and GHSV of 1000 h–1 within a the temperature range of 240–280°С for 40–90 h of continuous operation. The highest values of output and selectivity to C5+ hydrocarbons are obtained for composite catalyst Со-Al2O3/SiO2(35%)/ZSM-5(30%)/Al2O3(30%) at a temperature of 240°C and are 106 kg/($${\text{m}}_{{{\text{cat}}}}^{3}$$ h) and 67.1%, respectively. It is shown that using Co-Re/Al2O3 instead of Со-Al2O3/SiO2 catalyst produces comparable values of catalytic activity, but considerably fewer unsaturated hydrocarbons are found in the products of synthesis. Using Co-Re/TiO2 catalyst and raising the temperature (to 280°С) shifts the molecular weight distribution of the products of synthesis toward the formation of a gasoline fraction. It is found that the rate of catalyst deactivation grows in the order Со-Al2O3/SiO2 > Co-Re/Al2O3 > Co-Re/TiO2.

Conversion of Oxygenates to Aromatic Hydrocarbons on a Commercial Zeolite Catalyst: Comparison of Ethanol and Dimethyl Ether

Conversion of oxygenates to aromatic hydrocarbons in the syngas medium in the presence of a commercial zeolite-containing catalyst was studied. The influence of pressure on aromatization of dimethyl ether and ethanol was examined. At 400°C, an increase in the pressure from 0.1 to 3.0–10.0 MPa leads to a sharp increase in the yield of aromatic compounds. Dimethyl ether and ethanol, which are isomers belonging to different classes of compounds, were compared as substrates in conversion to aromatic hydrocarbons. At elevated pressure, dimethyl ether compared to ethanol exhibits higher selectivity in formation of the desired synthesis products, allowing synthesis of liquid hydrocarbons with increased content of arenes.

The Influence of the Cobalt-Containing Component of the Composite Catalyst on the One-Stage Process for Synthesis of Liquid Hydrocarbons from CO and H2

The influence of the cobalt-containing component (Co-Al2O3/SiO2, Co-Re/Al2O3 and Co-Re/TiO2) of a composite catalyst was studied in the Fischer – Tropsch combined process for synthesis and hydrotransformation of hydrocarbons. A flow fixed-bed reactor was used for characterization of the catalytic properties at 2 MPa, flow rate 1000 h–1, 240–280 °C for 40–90 hours of continuous operation. The highest productivity and selectivity to C5+ hydrocarbons equal to 106 kg/(m3 cat·ч) and 67.1 %, respectively, was characteristic of the composite catalyst Co-Al2O3/SiO2(35%)/ZSM-5(30%)/Al2O3(30%) at 240 °C. The comparable activities were observed with the catalysts Co-Re/Al2O3 and Co-Al2O3/SiO2 but the former provided the formation of unsaturated hydrocarbons in a lower proportion in the products. The use of the Co-Re/TiO2 catalyst at elevated temperature (up to 280 °C) allowed the molecular mass distribution of the products to be shifted towards the formation of the gasoline fraction. The rate of the catalyst deactivation was established to increase in the series Co-Al2O3/SiO2 > Co-Re/Al2O3 > Co-Re/TiO2.

Conversion of Dimethyl Ether to a Mixture of Liquid Hydrocarbons with Increased Triptane Content

The influence of the structural type and of the textural and acid properties of the zeolite on the catalyst selectivity in synthesis of a mixture of liquid hydrocarbons with increased content of isoalkanes from dimethyl ether was examined. The synthesis of liquid hydrocarbons enriched in triptane in the course of gasoline production from CO and H2 via dimethyl ether in the presence of La-H-Y zeolite was performed for the first time. Excess hydrogen in the system and relatively short contact time of the catalyst with the feed favor an increase in the triptane yield. Additional modification with palladium leads to optimization of the acid properties of the La-H-Y zeolite and, as a consequence, to an increase in the triptane content of the gasoline from 2.0 to 9.4 wt %.

Catalysts for Synthesis of Liquid Hydrocarbons from Methanol and Dimethyl Ether: Review

Various methods for improving the catalyst selectivity to conversion of oxygenates to liquid hydrocarbons are discussed. Literature analysis reveals that the key factors determining the selectivity of zeolite-containing catalysts are the structure type and acid properties of the zeolite. The strength and distribution of the acid sites are shown to depend on the structure type and chemical composition of the zeolite framework, as well as on the chemical nature of exchange cations. Methods for changing acid properties of zeolites are considered, among which are modifying with various cations, post-synthetic acid, alkali or steam treatment.

Hydrocracking of Fischer‐Tropsch Wax with Tungstovanadophosphoric Salts as Catalysts

AbstractThe synthesis of liquid hydrocarbons from CO2 and H2, based on renewable energy and H2O electrolysis, respectively, in a power‐to‐liquid process is a promising concept for the substitution of fossil fuels. Such a process is based on Fischer‐Tropsch synthesis followed by hydrocracking to convert waxy products into transportation fuels such as gasoline and diesel oil. Heteropolyacid cesium salts as catalysts show appropriate activity for hydrocracking, and the selectivity in cracking model hydrocarbons and Fischer‐Tropsch wax can be tuned by the vanadium content of the catalyst. Thermal stability and surface properties were investigated, and the catalysts are compared with a classical H‐Y‐type zeolite used for hydrocracking.

Role of zeolite in the synthesis of liquid hydrocarbons from CO and H2 on a composite cobalt catalyst

It is found that the main role of zeolite in Fischer–Tropsch synthesis on a composite Co catalysts is to reduce the average molecular weight of hydrocarbons produced from CO and H2 on acid sites. Secondary transformations of hydrocarbons on zeolites seem to occur via a carbocation mechanism. The total composition of synthesis products depends on the zeolite properties and the mutual arrangement of zeolite and cobalt active sites. It is shown that in some cases, introducing H-form zeolite into the Co catalysts for Fischer–Tropsch synthesis increases the productivity and the selectivity to synthetic oil and lowers the selectivity to methane.

Influence of dispersion medium composition on Fischer—Tropsch synthesis in three-phase system in the presence of iron-containing catalysts

The Fischer—Tropsch synthesis over iron-containing catalysts in a three-phase system with synthetic polymers of different compositions introduced into the dispersion medium has been studied. It has been found that these catalysts exhibit activity in the synthesis of liquid hydrocarbons from CO and H2. It has been revealed that the addition of synthetic polymers into the catalyst samples leads to the formation of smaller particles, the size of which depends on the employed polymer, and to an increase in the selectivity for the target product of the synthesis in the entire studied temperature range.

Efficiency of Gas-to-Liquids Technology with Different Synthesis Gas Production Methods

The design and optimization of a gas-to-liquids technology (GTL) is considered, mostly from the view of an optimal choice of a synthesis gas (syngas) production method. Material balance and energy efficiency are calculated for a number of flowsheets, which comprise syngas production by various techniques and Fischer–Tropsch (FT) synthesis of liquid hydrocarbons (LHs). Three different methods are considered for syngas production: combined steam and dry reforming; autothermal reforming; and partial oxidation. The FT process is considered in the version, which produces LHs, not waxes. The results of modeling manifest that the choice of syngas production method influences dramatically the efficiency of overall GTL technology. Ways to improve the efficiency of GTL technology are discussed.

Nature of active sites in hybrid metal-zeolite catalysts for the Fischer-Tropsch synthesis

The temperature-programmed reduction, powder X-ray diffraction, and oxygen titration were applied to study reducibility, phase composition, and structure of the active surface of the hybrid metal-zeolite catalysts Mβ@Co/Al2O3 (M = Pd, Co, and Fe). The results of physicochemical studies were compared with the data on activity and selectivity of the catalysts in the synthesis of liquid hydrocarbons from the synthesis gas. The nature of transition metal and the method of its introduction into the catalyst influence the composition of synthetic liquid hydrocarbons. A comparison of the Feβ@Co/Al2O3 catalyst prepared by the ion-exchange method that exhibits the highest activity in the synthesis of liquid hydrocarbons with a similar catalyst Fe/(Hβ@Co/Al2O3) prepared by the impregnation method indicated a distinct advantage of the ion exchange procedure. A mechanism of isomerization and cracking of primary linear alkanes on the M n δ+ clusters in the Mβ@Co/Al2O3 systems was proposed. The mechanism explains the main features governing the group and fractional composition of the obtained synthetic hydrocarbons.

A new technology for producing synthetic liquid hydrocarbons from gaseous hydrocarbons

Conventional technologies of synthetic liquid fuels (SLF) production from gaseous hydrocarbons by producing synthesis gas and synthesizing synthetic liquid hydrocarbons are examined. A high-efficiency SLF production technology that allows creation of high-efficiency autonomous units of specific capacities, including small ones, eliminates use of oxygen for producing synthesis gas and reduces energy consumption by thorough utilization of the heat of process and energy flows, including low-potential, is described. In this technology, the hydrocarbon feedstock conversion processes and synthesis of liquid hydrocarbons are carried out with highly effective fine-grained catalysts under optimal temperature conditions in compact reactors of a new design. Efficient conversion of gaseous hydrocarbon feedstock right at the gas recovery sites to synthetic liquid fuels (SLF) holds wide prospects in solving many problems of energy security of regions. This will allow production of high-quality SLF that can be transported by conventional means (by tankers, containers, pipelines, etc.). In contrast to hydrocarbon gases, SLF can be stored and marketed by using the existing developed infrastructure [1]. Russia possesses enormous reserves of natural (NG) and associated petroleum gases (APG) and is a major supplier of energy resources to the countries of Western Europe. The largest oil and gas companies of the world have been working vigorously to develop and implement projects based on GTL (gas-to-liquid) technology in regions with substantial NG reserves [2]. Efficient conversion of NG to SLF may introduce corrections to the necessity of implementation of some costly projects. In that case: 1) there will be no need for constructing multi-kilometer trunk pipelines with compressor stations and their costly operation; 2) there will be no need for transit countries for NG transportation; 3) the seasonal NG supply factor will be solved; 4) there will be no need for building costly NG liquefying plants, special liquefied NG storing and dispatching terminals, special vessels for its transportation, receiving terminals with regasification plants, etc.; 5) the APG will be put into commercial production instead of burning in flares; and 6) noxious vehicular emissions will be reduced, which is of especial importance for solving environmental problems of large cities, and so on. Chemical and Petroleum Engineering, Vol. 48, Nos. 5‐6, Sept., 2012 (Russian Original Nos. 5‐6, May‐June, 2012)

Unraveling the Fischer–Tropsch mechanism: a combined DFT and microkinetic investigation of C–C bond formation on Ru

A combined modelling study on the Fischer-Tropsch Mechanism on Ru(0001). The DFT results presented herein approve the idea that the carbide mechanism is not the main reaction path in the synthesis of liquid hydrocarbons on Ru{0001}. The direct reaction of a CH(x)(s) species with a CO(s) species is kinetically and thermochemically preferred over CO dissociation and the hydrogenation of carbon monoxide can be seen as the initiation reaction of the hydrocarbon polymerisation process. Moreover, this study shows that CO dissociation is favoured over desorption on Ru{0001}, while on the analogue Co facet desorption is clearly favoured. This study therefore is an important further confirmation on new thinking in the Fischer-Tropsch synthesis. The fundamental insight gained in these studies will be of paramount importance for engineers optimising the FT process. Optimisation will not only lower the cost of FT fuels but simultaneously lower energy consumption and emissions.

Synthesis of hydrocarbons from CO and H2 in the presence of Co-Ru and Co-Pd catalysts containing aluminum oxide

The influence of additions of 0.1–0.5% Pd or Ru in a 10% Co/Al2O3 catalyst on its activity and selectivity in the synthesis of liquid hydrocarbons from CO and H2 has been studied. It has been shown that the bimetallic systems make it possible to carry out the synthesis of hydrocarbons with a higher extent of conversion of CO and a higher yield of C5+ carbons in comparison with the original Co catalyst. Co-Ru catalysts exhibit exceptionally high selectivity (up to 80%) with respect to the formation of liquid products. It has been demonstrated by temperature-programmed reduction (TPR) that the introduction of Pd an dRu promotes the reduction of Co at lower temperatures and the formation of cobalt aluminates.

Synthesis of hydrocarbons from CO and H2 using Co-mixed-oxide catalysts

The use of binary carriers made of oxides of silicon and Mg, Be, Zr, and Mn for Co catalysts for synthesis of liquid hydrocarbons from CO and H2 leads to an increase in their activity and selectivity in comparison with individual oxides, and also to an increase in the catalyzate of the isoparaffin content and that of hydrocarbons of the C11-C18 fraction.

Synthesis of Liquid Hydrocarbons from Carbon Monoxide and Water with a Hybrid Catalyst

Abstract Liquid hydrocarbons were produced from carbon monoxide and water at temperatures from 220 to 280°C and under moderately pressurized conditions (3 atm), by utilizing a hybrid catalyst composed of a Co/SiO2 catalyst and a CO shift conversion catalyst. Most of the steam, either added or formed, was converted to hydrogen in the reaction of H2O with CO on the CO shift catalyst.

合成ガスから液状炭化水素の合成

Synthesis of Liquid Hydrocarbons from Synthesis gas which has been largely commerciallized for producing morter fuels from coal are described on their present status and future prospect. Carbon number distribution of product hydrocarbon from Fischer-Tropsch (F-T) synthesis on iron, cobalt and ruthenium catalysts have been shown to follow well the Schulz-Flory law which is derived from the assumption that the chain propagation probability is independent of carbon number. The probability of chain propagation is well controlled by regulating potassium content in the catalyst (for iron) or by regulating the size of metal particles (for ruthenium). Hydrocarbons from F-T synthesis are rich in normal paraffins and olefins while those from methanol conversion on zeolite are composed of iso-paraffins and aromatics. Slurry phase F-T process is suggested to be the most promising as the indirect coal liquefaction process for next generation. It is pointed out from the chemical structure of product hydrocarbon that F-T process is suitable for producing kerosene and diesel fuel whereas the direct coal hydrogenation is favored for producing gasoline base oil.

CO/H2 and CO2/H2 reactions with amorphous carbon-metal catalysts

By metal impregnation of selected naturally occurring organic materials followed by controlled carbonization, metal semicoke catalysts can be readily prepared. These catalysts have been tested in the synthesis of hydrocarbons and alcohols from CO/H2 and CO2/H2 mixtures. Fe and Co preparations have been used. Relatively high temperatures are required when using these catalysts, which are quite active for synthesis using CO2 and H2. The pressure (5150 kPa) is very favorable both for the synthesis of liquid hydrocarbons (C5−C30) and alcohols (C1−C5).

Formation, phase composition, texture and catalytic properties of Co-MgO-Alumino-calcium catalysts in synthesis of hydrocarbons from CO and H 2

A study was made of the mechanism of formation of catalysts; a special feature of this mechanism is the interaction of components (calcium aluminates and basic carbonates of cobalt and magnesium); the carrier with a developed surface and the active component distributed on this surface are formed during this process. Catalysts show maximum selectivity in synthesis of liquid hydrocarbons from CO and H/sub 2/ with a degree of reduction of the metal of 65-84% and a dispersion (according to chemisorption of CO) of 6 x 10/sup -3/ - 10 x 10/sup -3/. Maximum yield of liquid hydrocarbons (114.1 g/nm/sup 3/) was obtained in the pressure of a system of 33Co-3MgO-64 talum treated with hydrogen at 550/sup 0/C.

Synthesis of liquid hydrocarbons from carbon monoxide and hydrogen in the presence of skeletal Co-Ni-Al catalyst at atmospheric pressure

1. A skeletal catalyst, prepared from a Co-Ni-Al alloy (1∶1∶2) by leaching, is active in the reaction for the synthesis of hydrocarbons from CO and H2. 2. At atmospheric pressure and an optimum reaction temperature of 190° the yield of liquid hydrocarbons reaches 93 ml/m3. In this connection gasoline and oil are formed in equal volume amounts.