Synfuels, limitations

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 ... 

It should be noted that for air, sea and truck transportation, electrification is not conceivable. For these applications, the only C02 emissions reduction option that will not limit growth will be in the use of clean fuels or synfuels. 

From the somewhat limited discussion presented in this chapter on net energy analysis, the value of conducting NBAs for energy- and synfuel-producing systems is apparent. The effort needed to complete detailed NBAs is a time-consuming task, but can provide the basic information needed to select the critical pathway to higher efficiency systems, and to help determine whether the desired results can be achieved. Without the perspective provided by an NBA, the effort to perfect a biomass energy system can easily be misdirected. 

The plant is owned and operated by New Zealand Synthetic Fuels Corporation Limited (Synfuel) with a shareholding of Government 75 percent and Mobil 25 percent. Mobil provides technical and management services to the company. 

The MTG process utilised by Synfuel is based on a fixed-bed adiabatic reaction system. This reaction is highly exothermic and heat generated is removed by recycle gas which limits the temperature rise in the MTG reactors to 420°C at the reactor outlet. Hot reactor effluent is cooled with waste heat being used to preheat recycle gas and to vaporise methanol feed to the DME reactor. 

All information published to date implies that the production of stable synfuels is possible but will require refining processes altered from those now required for petroleum. Stability research is currently focussing on both basic and applied considerations, and the results are encouraging. By continuing these efforts, it is hoped that stability will not be the limiting factor in providing adequate future fuel supplies. 

The diffusion problems in the hydrogenation of fatty oils and the mass transport limitations within the pore structure of Ni/Si02 catalysts have been studied by Coenen and coworkers (1) (5) (6). They demonstrated that edible oil hydrogenation is a structure insensitive reaction only when the active phase is located in pores with diameter wider than 50 A. Wilson et al. (3) also discussed the necessity of optimization of pore structure in order to hydroprocess synfuels, in liquid phase, with nickel catalysts. 

Synfuels may substitute crude oil, but limitations have to be considered (Schaub,... 

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