Fischer-Tropsch facilities

The largest Fischer-Tropsch facility based on natural gas is the Mossgas plant located in Mossel Bay, South Africa. Natural gas is converted to synthesis gas in a two-stage reformer and subsequently converted to hydrocarbons by SASOL s Synthol technology. The plant, commissioned in 1992, has a capacity of 7155 mVd (45,000 bbFd). 

Despite the limited number of commercial Fischer-Tropsch facilities that have been constructed to date, a wide variety of Fischer-Tropsch technologies have been employed (Table 18.1). 

The first commercial Fischer-Tropsch facility was commissioned in 1935, and by the end of the Second World War a total of fourteen plants had been constructed. Of these, nine were in Germany, one in France, three in Japan, and one in China. Both German normal-pressure and medium-pressure processes (Table 18.1) were employed. The cobalt-based low-temperature Fischer-Tropsch (Co-LTFT) syncrude produced in these two processes differed slightly (Table 18.2), with the product from the medium-pressure process being heavier and less olefinic.11 In addition to the hydrocarbon product, the syncrude also contained oxygenates, mostly alcohols and carboxylic acids. 

The indirect liquefaction processes include Fischer-Tropsch and coal to methanol. Both processes have operated on a commercial scale. For the past 25 years, a Fischer-Tropsch facility has operated in South Africa. Presently the South Africans are constructing an advanced and larger facility. Coal-to-methanol plants existed in the United States, but were replaced by natural gas-to-methanol facilities because it was more economical to do so. 

It should be pointed out that although the South African Fischer-Tropsch facility is operating at a commercial scale, it is operating under very different market and regulatory conditions than exist in the U.S. 

A total of nine Fischer-Tropsch Facilities were constructed, giving priority to the industrial area in Rhineland-Westphalia. The plant capacity of all FT facilities amounted to 740,000 t fuel per year. Approximately 40% of it went to the two central German facilities in Schwarzheide and Luetzkendorf. 

Olefins in the C3-320°C range had significant synthetic value, and additional olefins were produced by thermal cracking in some facilities. Acid-catalyzed and thermal olefin oligomerization were important technologies for the upgrading of Fischer-Tropsch products. 

After the Second World War a gas-to-liquids facility that employed an iron-based high-temperature Fischer-Tropsch (Fe-HTFT) process was constructed at Brownsville, Texas. The technology was developed by Hydrocarbon Research, Inc.,20 and the commercial facility was operated by the Carthage Hydrocol Company. The Hydrocol plant was in commercial operation during the period 1951-1957, and it was shut down mainly for economic reasons (the oil price was around US 2 per barrel at that time). 

Production of chemicals became increasingly important. The recovery of oxygenates from the Fischer-Tropsch aqueous product was expanded to include niche chemicals, such as 1-propanol.45 Ethylene and propylene extraction was increased and even supplemented by the addition of a high-temperature catalytic cracker.46 Linear a-olefin extraction units for the recovery of 1-pentene, 1-hexene, and 1-octene were added to the refinery,45-47 and a new facility for the extraction of 1-heptene and its... 

The South African government initiated the Mossgas project in the mid-1980s to investigate the conversion of gas and associated natural gas liquids into transportation fuel. This eventually led to the construction of the Mossgas gas-to-liquids plant (presently known as PetroSA) in Mossel Bay, South Africa. It was designed as a 33,000 barrels per day oil equivalent facility, with two thirds of the production being derived from Fischer-Tropsch synthesis and the remainder from associated gas liquids. This facility reached full commercial production in 1993 and was aimed at the production of transportation fuel only.50... 

The design intent was to produce transportation fuels, and the design did not specifically make provision for chemicals co-production. It is in principle possible to extract chemicals from the HTFT syncrude, such as the alcohols that are being recovered from the Fischer-Tropsch aqueous product. Extraction of linear a-olefins may also be considered, which has indeed been investigated,57 and many other opportunities exist. However, it should be noted that the Mossgas facility is much smaller than the Sasol Synfuels facility, and recovery of valuable products in HTFT syncrude may not have economy of scale. 

The fact that surface structure, in particular steps and coordinatively unsaturated sites, has an influence on the state and reactivity of carbon monoxide is entirely in keeping with the empirical correlation (Fig. 6) between heat of adsorption, electron binding energies, and molecular state. Elegant studies by Mason, Somorjai, and their colleagues (32, 33) have established that with Pt(lll) surfaces, dissociation occurs at the step sites only, and once these are filled carbon monoxide is adsorbed molecularly (Fig. 7). The implications of the facile dissociation of carbon monoxide by such metals as iron, molybdenum, and tungsten for the conversion of carbon monoxide into hydrocarbons (the Fischer-Tropsch process) have been emphasized and discussed by a number of people (32,34). 

In Sasolburg, South Africa, a commercial plant using the Fischer-Tropsch process was completed in 1950 and began producing a variety of liquid fuels and chemicals. The facility has been expanded to produce a considerable portion of South Africa s energy requirements (15,16). 

Developments Outside Germany, In the late 1930s experimental work in England (29—31) led to the erection of large pilot facilities for Fischer-Tropsch studies (32). In France, a commercial facility near Calais produced ca 150 m3 (940 bbl) of liquid hydrocarbons per day. In Japan, two full-scale plants were also operated under Ruhrchemie license. Combined capacity was ca 400 m3 (2500 bbl) of liquids per day. 

A variation on IGCC operation is to combine power generation with chemicals or fuels production, the so-called co-production option. In this operating mode, part of the syngas produced by the gasifier is used for power production and part is sent to a Fischer-Tropsch,25 methanol, or similar facility for fuels/... 

The summary withdrawal of Indiana s support was all the more galling to Mr. Kellogg because it meant Indiana had selected a rival company, Hydrocarbon Research, Inc., to be its partner in development, design, and construction of a hydrocarbon synthesis facility. Mr. P. C. ( Dobie ) Keith had founded Hydrocarbon Research for the specific purpose of developing an American version of Germany s Fischer-Tropsch synthesis. Keith s Hydrocol Process would use bubbling fluid bed reactors. 

These routes have some very attractive features, with hydrogen, acetylene and a little coke being almost the sole products. The systems can be made self-quenching which is a major advantage however, the conversion per pass is at most 50% with unacceptable power consumption. Indeed, we estimate that the power generating facilities for such a route alone would cost about as much as a Fischer-Tropsch plant with the same net hydrocarbon production rate. To the best of our knowledge this route is not presently practised on a commercial scale. 

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... 

The company Sasol operates a synthetic fuel production facility consisting of 48 coal gasification (Lurgi) units. The product gas is generated at a rate of 2.1 million Nm /h with a 38 % hydrogen share and is used for gasoline and diesel production by means of Fischer-Tropsch synthesis [78]. 

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