Synfuel

Because of the ovedapping roles of coal in industry, many of the technologies covered here have been developed for synthetic fuel appHcations, but they also have been used or have demonstrated potential for production of significant quantities of chemicals. The scope of an article on coal as a chemical source would not be complete without coverage of synfuel processes, but the focus will be on the chemical production potential of the processes, looking toward a future when coal again may become the principal feedstock for chemical production. 

Various processes can be used to produce energy or gaseous, liquid, and solid fuels from biomass and wastes. In addition, chemicals can be produced by a wide range of processing techniques. The following Hst summarizes the principal feed, process, and product variables considered in developing a synfuel-from-biomass process. 

Fig. 3. Effect of feed moisture content on energy available for synfuel production. Assumes feed has a heating value of 11.63 MJ /kg (5000 Btu/lb) dry. A, 0% moisture in dried feed B, 30% moisture in dried feed. For example, reduction of an initial moisture content of 70 wt % by thermal drying to 30% moisture content requites the equivalent of 37% feed energy content and leaves 63% feed energy available for SNG production.

Sepa.ra.tlon, It maybe desirable to separate the feedstock into two or more components for different appHcations. Examples include separation of agricultural biomass into foodstuffs and residues that may serve as fuel or as a raw material for synfuel manufacture, separation of forest biomass into the darker bark-containing fractions and the pulpable components, separation of marine biomass to isolate various chemicals, and separation of urban... 

Combustion. Coal combustion, not being in the strictest sense a process for the generation of gaseous synfuels, is nevertheless an important use of coal as a source of gaseous fuels. Coal combustion, an old art and probably the oldest known use of this fossil fuel, is an accumulation of complex chemical and physical phenomena. The complexity of coal itself and the variable process parameters all contribute to the overall process (8,10,47—50) (see also COLffiUSTION SCIENCE AND technology). 

Fig. 2. Process flow sheet of (a) Sasol One and (b) the Sasol synfuel process for Sasol Two and Three (36). LPG is Hquefied petroleum gas other terms are...

The MTG process was developed for synfuel production in response to the 1973 oil crisis and the steep rise in crude prices that followed. Because methanol can be made from any gasiftable carbonaceous source, including coal, natural gas, and biomass, the MTG process provided a new alternative to petroleum for Hquid fuels production. New Zealand, heavily dependent on foreign oil imports, utilizes the MTG process to convert vast offshore reserves of natural gas to gasoline (59). 

J. E. Skior, Technical Economics, Synfuels, and Coal Energy 1989, ASME, pp. 103—109. 

A notable difference between the newer large machines and the somewhat smaller units is the use of multiple, reverse-flow can combustors configured annulady. Because the individual cans are relatively small, they reportedly lend themselves well to laboratory experimentation with various fuel types, including reduced-heat value synfuels (see Fuels, synthetic). A dry, low NO version of the can combustors has been developed for both gas and hquid fuel firing. NO emissions can reportedly be held below 25 ppm when firing gas fuel. By employing water injection, NO emissions can be held below 60 ppm for oil-fired units. 

Ricci, L. (1982). Synfuels Engineering. New York McGraw-Hill. 

The Sasol Synfuel refinery in Secunda, South Africa, produces synthetic iuels for consumers. (Gorbis Corporation)... 

Matar, S., Synfuels, Hydrocarbons of the Euture, Penn Well Publishing Company, 1982, p. 38. 

Brown, R. S., Hausler, D. W., Taylor, L. T., and Carter, R. C., Fourier transform infrared spectrometric detection in size-exclusion chromatographic separation of polar synfuel material, Anal. Chem., 53, 197, 1981. 

Sasol Advanced Synthol Fused Fe Fixed fluidized bed 1995 Synfuels, Secunda, South Africa... 

The Sasol 2 and 3 facilities (presently known as Sasol Synfuels) were constructed in Secunda, South Africa, in response to the 1973 oil crisis. Syncrude was produced by Fe-HTFT synthesis in improved Sasol Synthol circulating fluidized bed reactors36. The syncrude composition was similar to the Kellogg Fe-HTFT syncrude of Sasol 1 (Table 18.8). There was limited integration between the two facilities, which had a combined nameplate capacity of 120,000 barrels per day oil equivalent. 

The evolution of Sasol Synfuels was not limited to the refinery only, and the following important changes took place ... 

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