Fischer-Tropsch synthesis slurry process

As a second example, we have the Fischer-Tropsch synthesis. This process allows producing liquid hydrocarbons of high molecular mass with long carbon-chain molecules (such as gasoline, kerosene, diesel, and lubricant) from synthesis gas (CO-I-H2). This process takes place in slurry bed reactors, where the reactant gases flow through a liquid mixture inert. 

One of the most important, and perhaps the best studied, applications of three-phase fluidization is for the hydrogenation of carbon monoxide by the Fischer-Tropsch (F-T) process in the liquid phase. In this process, synthesis gas of relatively low hydrogen to carbon monoxide ratio (0.6 0.7) is bubbled through a slurry of precipitated catalyst suspended in a heavy oil medium. The F-T synthesis forms saturated and unsaturated hydrocarbon compounds ranging from methane to high-melting paraffin waxes (MW > 20,000) via the following two-step reaction ... 

AGC-21 A process for converting natural gas to liquid fuels in three stages generation of syngas in a fluidized bed, Fischer-Tropsch synthesis in a slurry bubble column reactor, and hydrocracking. Piloted in 1997 and proposed for installation in Qatar. 

In 1976 he was appointed to Associate Professor for Technical Chemistry at the University Hannover. His research group experimentally investigated the interrelation of adsorption, transfer processes and chemical reaction in bubble columns by means of various model reactions a) the formation of tertiary-butanol from isobutene in the presence of sulphuric acid as a catalyst b) the absorption and interphase mass transfer of CO2 in the presence and absence of the enzyme carboanhydrase c) chlorination of toluene d) Fischer-Tropsch synthesis. Based on these data, the processes were mathematically modelled Fluid dynamic properties in Fischer-Tropsch Slurry Reactors were evaluated and mass transfer limitation of the process was proved. In addition, the solubiHties of oxygen and CO2 in various aqueous solutions and those of chlorine in benzene and toluene were determined. Within the framework of development of a process for reconditioning of nuclear fuel wastes the kinetics of the denitration of efQuents with formic acid was investigated. 

Of the technological modifications, Fischer-Tropsch synthesis in the liquid phase (slurry process) may be used to produce either gasoline or light alkenes under appropriate conditions249,251 in a very efficient and economical way.267 The slurry reactor conditions appear to establish appropriate redox (reduction-oxidation) conditions throughout the catalyst sample. The favorable surface composition of the catalyst (oxide and carbide phases) suppresses secondary transformations (alkene hydrogenation, isomerization), thus ensuring selective a-olefin formation.268... 

Gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are widely used in the chemical and petrochemical industries for processes such as methanol synthesis, coal liquefaction, Fischer-Tropsch synthesis and separation methods such as solvent extraction and particle/gas flotation. The hydrodynamic behavior of gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are of great importance for the design and scale-up of reactors. Although the hydrodynamics of the bubble and slurry bubble columns has been a subject of intensive research through experiments and computations, the flow structure quantification of complex multi-phase flows are still not well understood, especially in the three-dimensional region. In bubble and slurry bubble columns, the presence of gas bubbles plays an important role to induce appreciable liquid/solids mixing as well as mass transfer. The flows within these systems are divided into two... 

Bubble column reactors (BCR) are widely used in chemical process industries to carry out gas-liquid and gas--liquid-solid reactions, the solid suspended in the liquid phase being most frequently a finely divided catalyst (slurry reactor). The main advantages of BCR are their simple construction, the absence of any moving parts, ease of maintenance, good mass transfer and excellent heat transfer properties. These favorable properties have lead to their application in various fields production of various chemical intermediates, petroleum engineering, Fischer-Tropsch synthesis, fermentations and waste water treatment. 

Development of the process in Germany was expedited when Ruhrchemie and I.G. Farbenindustrie pooled their facilities about 1940. Results of laboratoiy- and bench-scale operations led to the construction of a demonstration unit at Leuna employing a catalyst slurry in a continuous two-stage process with an output of metric tons of alcohds per day. The olefin feed was obtained by mild thermal cracking of soft paraffin wax from the Fischer-Tropsch synthesis. The product, a mixture of alcohols, was readily sulfonated to detergents, which were in great demand in... 

A considerable interest has been expressed in using the SBCR to carry out FTS particularly for the conversion of stranded natural gas into liquids. Currently, the Center for Applied Energy Research (CAER) is utilizing a Prototype Integrated Process Unit (PIPU) system for scale-up research of the FTS. The purpose of this study was to compare the performance and activity decline of a precipitated Fe/K Fischer Tropsch Synthesis (FTS) catalyst in a revamped slurry bubble colurtm reactor (SBCR) to that of previous CSTR and SBCR rans using the same catalyst and operating conditions. The activity decline measured in the revamped SBCR system was shown to be similar to that of the CSTR experiments. The apparent activity decline in a previous SBCR run was due a transient startup effect from the slurry filtration system. 

Fischer-Tropsch synthesis reactions were performed in a slurry CSTR with a reactor volume of 1 liter. The catalyst samples were reduced at 623K for 10 hours (H2 He = 1 2) ex-situ in a flow reactor prior to reaction. The process conditions used in this study were HaiCO = 2.0, T = 220°C, P = 275 psig and SV = 5 SL/h gcat- Syngas conversion levels were determined by on-line gas sampling. Further details of the experimental conditions and reactor operation can be found in ref. 4. 

D. Casanave, P. Galtier and J-C. Viltard, Process and Apparatus for operation of a slurry bubble column with application to the Fischer-Tropsch synthesis , U.S. Patent 5,961,933, 5 October 1999. 

One of the most widely-used three-phase reactors is the trickle-hed reactor which is particularly favored hy the hydroprocessing industry. On the contrary, slurry systems are prefered in the chemical industry they are used in direct coal liquefaction processes and in Fischer-Tropsch synthesis. 

Wang Y, Fan W, Liu Y, Zeng Z, Hao X, Chang M, Zhang C, Xu Y, Xiang H, Li Y. Modeling of the Fischer-Tropsch synthesis in slurry bubble column reactors. Chem. Eng. Process. 2008 47 222-228. 

Deckwer WD, Serpemen Y, Ralek M, Schmidt B. Modeling the Fischer-Tropsch synthesis in the slurry phase. Ind. Eng. Chem. Process. Des. Dev. 1982 21 231-241. 

Slivinskh EV, Kliger GA, Kuz min AE, Abramova AV, Shuikin AN. Fischer-Tropsch synthesis in a fixed-bed reactor in the slurry process advantages and prospects. Kinet. Catal. 1999 40 338-344. 

Bhatt BL, Tijm PJA. Slurry phase Fischer-Tropsch synthesis process development. Fifteenth Annual Pittsburgh Coal Conference Proceedings, Pittsburgh, PA September 14-18, 1998. 

The considerations for methanol production are valid also for manufacture of synfuels. The manufacture of synthetic gasoline by the Mobil MTG (Yurchak, 1988) or Topsoe TIGAS process (Topp-Joergensen, 1988) proceeds via methanol or dimethylether as intermediate. Diesel can be manufactured by the Fischer-Tropsch synthesis followed by hydrocracking of the wax product (v.d. Burgt et al., 1988). Slurry b Fischer-Tropsch processes for diesel may operate at a Hj/CO ratio slightly lower than for methanol synthesis (Dry, 1988). 

The catalytic hydrogenation of fatty oils, the desulfurization of liquid petroleum fractions by catalytic hydrogenation, Fischer-Tropsch-type synthesis in slurry reactors, and the manufacture of calcium bisulfite acid are familiar examples of this type of process, for which the term gas-liquid-particle process will be used in the following. 

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