Slurry Phase Reactor Research Articles

99/03622 Temperature effect on liquefaction and chemical conversion of organic matter of the Borodino coal at rapid heating rates: Soldatov, A. P. Neftekhimiya, 1998, 38, (3), 233–238. (In Russian)

The effects of Manganese (Mn) incorporation on a precipitated iron-based Fischer-Tropsch synthesis (FTS) catalyst were investigated using N2 physical adsorption, air differential thermal analysis (DTA), H2 temperature-programmed reduction (TPR), and Mössbauer spectroscopy. The FTS performances of the catalysts were tested in a slurry phase reactor. The characterization results indicated that Mn increased the surface area of the catalyst, and improved the dispersion of α-Fe2O3 and reduced its crystallite size as a result of the high dispersion effect of Mn and the Fe-Mn interaction. The Fe-Mn interaction also suppressed the reduction of α-Fe2O3 to Fe3O4, stabilized the FeO phase, and (or) decreased the carburization degree of the catalysts in the H2 and syngas reduction processes. In addition, incorporated Mn decreased the initial catalyst activity, but improved the catalyst stability because Mn restrained the reoxidation of iron carbides to Fe3O4, and improved further carburization of the catalysts. Manganese suppressed the formation of CH4 and increased the selectivity to light olefins (C=2–4), but it had little effect on the selectivities to heavy (C5+) hydrocarbons. All these results indicated that the strong Fe-Mn interaction suppressed the chemisorptive effect of the Mn as an electronic promoter, to some extent, in the precipitated iron-manganese catalyst system.

Low temperature Fischer–Tropsch synthesis from a Sasol perspective

The characteristics of a slurry phase reactor are contrasted with those of a conventional tubular fixed bed reactor (TFBR) for the conversion of synthesis gas to long chain hydrocarbons. Hydrodynamic information needed for the design of a commercial scale slurry phase Fischer–Tropsch (FT) reactor were obtained from experiments carried out on a 1 m internal diameter pilot plant reactor. The kinetics, selectivities and deactivation mechanisms of Fe and supported Co FT catalysts are compared for both slurry phase and fixed bed operation. The combined advantages of the slurry phase reactor and a very active Co catalyst create the opportunity to convert remote natural gas to high quality middle distillates in a cost effective manner.

97/03723 Synthetic diesel fuel and process for its production

Catalytic reaction performances of home-made mesoporous MnO2-supported Fe-based catalyst with copper promoter for Fischer–Tropsch synthesis (FTS) are investigated in a slurry-phase reactor at 533 K–573 K and 1.0 MPa. The present catalyst system exhibits high olefin selectivity, however, the selectivity to ethylene is lower than the extrapolation based on the C3+. Simultaneously, the catalyst gives high oxygenates productivity except for the C1 oxygenates. Comprehensive product distributions including hydrocarbon and oxygenates at different temperatures are presented. Particular attention is paid to the new overall distribution of product based on the carbon numbers when the hydrocarbon is combined with oxygenates. The new distributions at different temperatures show similar trends, displaying low C1 product selectivity and almost accordant C2 product selectivity with the extrapolation from Anderson–Schulz–Flory (ASF) law. An attempt is made to elucidate the deviation behavior of C1 and C2 hydrocarbon.

Biological treatment of a soil contaminated with diesel fuel using periodically operated slurry and Solid Phase Reactors

A silty clay loam contaminated with diesel fuel was treated in the laboratory using periodically operated slurry and solid phase bioreactors. Soil Slurry-Sequencing Batch Reactors (SS-SBRs) were operated with a 40% solids concentrations (w/v) to determine the effect of hydraulic residence time and volumetric replacement strategy on performance. Solid Phase-Sequencing Batch Reactors (SP-SBRs) were operated with the same silty clay loam artificially contaminated with diesel fuel. Different periodic aeration strategies were investigated in the SP-SBRs in an attempt to minimize volatile losses without sacrificing overall removal efficiency.Results showed that a day 10 HRT in the SS-SBRs was optimal for the soil tested. The rate and extent of diesel fuel removal was increased by providing a higher concentration of diesel fuel at the beginning of the SBR cycle, indicating that removal rates are not zero-order. The findings also showed that a properly operated periodic venting strategy produced high overall removal efficiencies with considerably less volatilization than continuous aeration.

Biological treatment of a soil contaminated with diesel fuel using periodically operated slurry and solid phase reactors

A silty clay loam contaminated with diesel fuel was treated in the laboratory using periodically operated slurry and solid phase bioreactors. Soil Slurry-Sequencing Batch Reactors (SS-SBRs) were operated with a 40% solids concentrations (w/v) to determine the effect of hydraulic residence time and volumetric replacement strategy on performance. Solid Phase-Sequencing Batch Reactors (SP-SBRs) were operated with the same silty clay loam artificially contaminated with diesel fuel. Different periodic aeration strategies were investigated in the SP-SBRs in an attempt to minimize volatile losses without sacrificing overall removal efficiency. Results showed that a day 10 HRT in the SS-SBRs was optimal for the soil tested. The rate and extent of diesel fuel removal was increased by providing a higher concentration of diesel fuel at the beginning of the SBR cycle, indicating that removal rates are not zero-order. The findings also showed that a properly operated periodic venting strategy produced high overall removal efficiencies with considerably less volatilization than continuous aeration.

Evolution of Alcohol Synthesis Catalysts under Syngas

Methanol-higher alcohols mixtures can be synthesized from natural gas via CO/CO[sub 2]/H[sub 2] mixtures and constitute potential octane boosters for unleaded gasoline. Catalytic formulations have been developed around the world, which allow rather high alcohol selectivities to be reached, but these performances are generally attained after an aging period which is necessary for the in situ preparation of the active phase. For this reason, the evolution of copper-cobalt-based model catalysts has been studied in different test equipment and operating conditions, such as fixed bed, slurry phase, and Berty reactors, as well as autoclaves and differential scanning calorimeters (DSC). The evolution of metallic cobalt dispersion was followed by magnetic measurements, and carbon deposits were visualized by temperature-programmed hydrogenation experiments. The interest of a slurry reactor for alcohols synthesis is demonstrated at lab scale. Acetaldehyde thermodesorption and CO disproportionation allow the performances of cobalt-based active phases to be predicted.

Improved hydrogenation catalysts for coal-derived liquids

Benzene, naphthalene and biphenyl hydrogenation in a slurry-phase reactor were used as probe reactions to investigate the influence of bimetallic catalyst formulatons and altervalent carrier doping on hydrogenation activity and sulphur-poisoning characteristics. It was found that addition of a secondary metal such as Pd, Ir or Re to primary metals such as Pt, Rh, or Ru, has a beneficial influence on these parameters. Signifcant enhancements in hydrogen adsorption capacity, hydrogenation activity and sulphur tolerance were observed when metals were dispersed on TiO 2 doped with higher-valence cations. The enhancement factors were found to be a function of the dopant concentration en the carrier

Iron-based catalysts for slurry-phase Fischer-Tropsch process: Technology review

The slurry-phase reactor system is of interest in Fischer-Tropsch synthesis owing to the ability of the reactor system to efficiently remove the heat produced by the exothermic reaction. Iron-based catalysts are active for Fischer-Tropsch synthesis and for the water-gas shift reaction, and, in addition, are inexpensive. Hence, they have been examined in slurry-phase Fischer-Tropsch synthesis with CO-rich synthesis gas. The role of promoters, carbide phases, and oxide phases in iron-based catalysts is not well understood. The article reviews current knowledge of iron-based catalysts with reference to their application in slurry-phase Fischer-Tropsch synthesis. Areas of investigation requiring further research are identified.

The fischer-tropsch process - commercial aspects

This review is an update of previous reviews dealing with the Sasol process, the catalysts used, the control of selectivity, the kinetics and the mechanism of the F-T reaction. The emphasis is on the practical aspects. With regard to reactor developments two new types have now been put into commercial production, namely a 45 bar multi-tubular fixed bed reactor for wax production and an alternative type of fluidised bed reactor for light oil production. The latter reactor costs much less to construct and to operate than the older circulating fluidised bed reactors. The slurry phase reactor concept is now entering the demonstration size stage of development. Improved olefin oligomerisation catalysts have resulted in a better quality diesel fuel being made in downstream upgrading. The best way of producing maximum and high quality diesel is to maximise wax production and then to selectivity hydrocrack it. A comparison is made between the two existing Sasol processes and the proposed Shell Middle Distillate process.

Kinetic studies for elucidation of the promoter effect of alkali in Fischer-Tropsch iron catalysts

The kinetics of the formation of hydrocarbons in Fischer-Tropsch synthesis and of consecutive reactions, i.e., hydrogenation and double bond isomerization of primarily formed 1-alkenes, were studied in a slurry-phase reactor using alkalized and nonalkalized precipitated iron catalysts. Both consecutive reactions have an order of about −2 with respect to carbon monoxide and an order of about 1 with respect to 1-alkenes. The order with respect to hydrogen is 1 for the hydrocarbon formation and also 1 for the consecutive hydrogenation, but 0 for the consecutive isomerization. The reaction orders are not changed by addition of K 2CO 3 to the catalyst. The kinetics of consecutive reactions can be interpreted by competitive adsorption of 1-alkene and carbon monoxide. Alkali addition causes an increase in the strength of carbon monoxide adsorption and consequently a decrease in 1-alkene adsorption so that the rates of the consecutive reactions are reduced. This hypothesis could be proved by studies of 1-hexene hydrogenation in the presence and absence of carbon monoxide for alkalized and nonalkalized iron catalysts. The kinetics were studied in the ranges 1.3 < P CO(10 5Pa) < 7, 1.6 < P H2(10 5Pa) < 9, and 490 K < T < 530 K.

Composition of liquid products from catalytic hydrotreatment of flash pyrolysis tars: 2. Slurry-phase reactor products

The compositions of the oils obtained by catalytic hydrotreatment of flash pyrolysis tars in a slurry-phase reactor using red mud as catalyst were determined by g.c. The tars were from Millmerran subbituminous and Piercefield bituminous coals. In both cases the major components of the oils produced at 460 °C were simple phenols, alkyl-substituted naphthalenes, polycyclic aromatic hydrocarbons and n-alkanes (C 6–C 30). The effect of processing temperature in the range 419–460 °C was determined for the subbituminous coal. The increased volatility of the 460 °C product was accompanied by increased concentrations of simple phenols and aromatics, including the polycyclic aromatics, and a decrease in the relative proportions of longer-chain n-alkanes, owing to increased gas formation. Comparison of the product compositions with those from a two-stage trickle-bed reactor shows that the slurry-phase products are characterized by: 1. (1)alkylphenols (as opposed to alkylcyclohexanes for the trickle-bed products) as the major single-ring products; 2. (2)alkylnaphthalenes (as opposed to alkyltetralins) as the major two-ring products; 3. (3)higher concentrations of polycyclic aromatic hydrocarbons; and 4. (4) lower concentrations of n-alkanes. Hydrocracking of product oils would be necessary to reduce aromaticity.

Upgrading of flash pyrolysis tars to synthetic crude oil: 4. Hydrotreatment with iron catalyst in a slurry-phase reactor

Flash pyrolysis tars, produced from Millmerran (Queensland subbituminous) and Piercefield (New South Wales bituminous) coals, have been hydrogenated in a slurry-phase bubble-column reactor using red mud and sulphur as catalyst. Oils of low coking propensity and high volatility were produced from both coal tars. The slurry-phase reactor successfully overcame the severe coking problems previously encountered when hydrogenating flash pyrolysis tars in fixed-bed reactors, completely eliminating coke formation. For Millmerran coal tar the effect of reaction temperature on reactor performance was investigated in the range 420–460 °C. The major effects of increasing temperature were to reduce the coking propensity of the product oil and to increase its volatility. Product oils from both tars were high in aromatics and heteroatoms, and the distillate fractions derived from these oils would require further refining to produce finished products (i.e., gasoline and diesel). It should be possible to achieve this using conventional refining technology.

The photosensitized oxygenation of olefins with reactors of different types

A comparative kinetic investigation of the homogeneous and heterogeneous dye-sensitized photooxygenation of 2,3-dimethyl-2-butene and 2-methyl-2-butene in two photochemical reactors. namely in the anular reactor and in a cylindrical reactor of original design inside an elliptical mirror, is reported. The merits of these two laboratory photochemical reactors are discussed, with particular emphasis on their mass transfer performances in this gas—liquid and gas—liqui—solid reaction. Two types of régimes exist. dynamic and chemical, in which the reaction takes place, according to the experimental conditions. In the anular reactor the presence of a wide dynamic régime is a severe hindrance for an adequate chemical kinetic analysis. The cylindrical reactor with special features for speeding up the mass transfer rate is a considerable improvement, as shown by a higher precision of the kinetic constants calculated through a statistical approach. This cylindrical reactor was also used as a slurry phase reactor with methylene blue supported on silica gel as a photosensitizer. The singlet oxygen production and quenching rates on the heterogeneous photosensitizer were then computed.