Fischer−Tropsch Fuel for Use by the U.S. Military as Battlefield-Use Fuel of the Future

Abstract

The United States Department of Defense (DoD) has been interested in low-sulfur, environmentally cleaner Fischer-Tropsch (FT) fuels since 2001 because they want to be less dependent upon foreign crude oil and ensure the security of the supply. A three-phase Joint Battlefield-Use Fuel of the Future (BUFF) program was initiated to evaluate, demonstrate, certify, and implement turbine fuels produced from alternative energy resources for use in all of its gas turbine and diesel engine applications. Sasol Synfuels International (Pty) Ltd. and Sasol Chevron Holdings Ltd., among others, were invited to participate in the program with the objective to supply the DoD with a FT BUFF that conforms to Jet Propulsion 8 (JP-8) and JP-5 fuel volatility and lowtemperature fluidity requirements. Although the DoD is more interested in coal-to-liquid (CTL) technology, the product from a gas-to-liquid (GTL) Products Work-Up Demonstration Unit in Sasolburg, South Africa, was used to evaluate (on a bench scale) the possibility of producing a BUFF fraction from the Sasol Slurry Phase Distillate (Sasol SPD) low-temperature FT (LTFT) process and Chevron Isocracking technology. It was concluded from the study that the production of a synthetic FT BUFF is feasible using the Sasol SPD LTFT technology together with the current Chevron isocracking technology. The product yield for a BUFF conforming to JP-8 requirements is 30 vol % of the fractionator feed, whereas the product yield for a BUFF conforming to the JP-5 volatility requirement is slightly less than 22 vol % of the fractionator feed. Also concluded from the study was that the end point of the Sasol SPD LTFT BUFF will be restricted by the freezing point requirement of the DoD and not the maximum viscosity requirement. One would therefore need to optimize the hydrocracking process conditions to increase the Sasol SPD LTFT BUFF product yield.

A review on coal-to-liquid fuels and its coal consumption

“…Several major American coal companies have expressed interest in CTL-technology or created blueprints and studies for CTL-plants [55,56]. The US military has expressed concern over the dependence on foreign oil and studied alternatives derived from CTL or possibly BTL [57,58]. Feasibility studies and evaluation programs are being pursued, but no full scale program has yet been implemented.…”

Performance and durability of a generator set CI engine using synthetic and petroleum based fuels for military applications

“…The cetane number affects coldstarting, combustion noise, and exhaust emissions. A fuel with lower cetane number can shift the timing of combustion considerably, especially at high speed -light load operating conditions, and this might lead to incomplete combustion and elevated emissions [8].…”

“…Lower viscosity may lead to an increase in leakage losses from the pumping elements, and thus might cause a reduction in the amount of injected fuel quantity. Viscosity of the fuel also has an effect on the atomization and spray patterns of the fuel injectors, which can strongly affect the performance of an engine [8].…”

“…This initiative provides that US energy independence can begin with a national alternative fuel initiative to provide the US military with a secure domestic supply of clean fuel synthesized from domestic resources. Investigation of various fuels such as ultra-low sulfur diesel (ULSD) [2,4], synthetic fuels [5][6][7][8][9][10][11], JP-8/JP-5 [12][13][14], and blends of biodiesel [15][16][17][18][19][20] in military applications is necessary to identify the required operational performance and potential issues. The problematic long-term supplies of oil and increasing knowledge of health effects of JP-8 [21], however, have recently encouraged the US military to develop a new synthetic-8 fuel (S-8), an alternative to JP-8.…”

“…Since the mid-1990s, the world's major energy companies have started to develop modern F-T processes that are less expensive to build and operate. F-T synthetic fuels using this technology should result in reduced exhaust emissions from military diesel engines, including reduced diesel exhaust particulate matter [6][7][8]11]. These fuels also demonstrate low lubricity, which can be improved with military approved lubricity improvers [8,22].…”