Alpha Natural Resources is getting ready to test an LNG fuel system from GFS Corp on three 240-ton Caterpillar 793D mining trucks at a Powder River Basin coal mine near Gillette in northeast Wyoming.
The GFS system allows mine haul trucks to use liquefied natural gas for 50% to 70% of their total fuel requirement. GFS refers to the system as bi-fuel.
The converted trucks will be operated at Alpha’s Belle Ayr mine for both overburden and coal haul service, GFS said in announcing the program this past summer.
Florida-based GFS is stepping up promotion of its Evo-MT conversion systems allowing diesel-natural gas operation. The Evo-MT 7930 is for Cat 793-series vehicles and the Evo-MT 7770 is for Cat 777 series trucks, as has been demonstrated in Harlan County, Ky. (F&F, November 8, 2010).
“Trucks converted to diesel-plus-LNG operation exhibit diesel-like performance in such critical areas as power, response and efficiency,” GFS says. Installations are performed onsite “without significant modification to the vehicle or engine utilizing conventional shop facilities and general technical labor.”
The vehicles may continue to be operated on diesel, or with the emissions-reducing and money-saving LNG.
Key GFS components include a proprietary air-gas mixing device for blending engine intake air with natural gas. “Mixing of air and gas is achieved using a sophisticated, fixed-venturi design that avoids the use of an efficiency robbing throttle plate,” the company says.
“The low restriction air-gas mixer ensures that adequate air-flow is maintained to the engine and that operating efficiencies are not compromised… The computer-aided-design mixer is built to aerospace tolerances using CNC machining processes and is assembled using state-of-the-art welding techniques. The finished mixer has no moving parts and once installed in the engine air-intake system requires no routine maintenance.”
GFS has experience in natural gas engine conversions ranging from small on-road vehicles to stationary power, dating back to 1978. The company is focused now providing “fully integrated alternative fuel solutions for the mining, construction and rail markets.”
GFS is working with Houston- and Redmond, Wash.-based Prometheus Energy for onsite LNG fuel supply.
Alpha makes mention of a $1 million test of LNG at the Belle Ayr mine in Wyoming in its recent sustainability report, stating that “laboratory tests indicate that the substitution of up to 50% LNG in diesel engines has the potential to reduce fuel consumption and engine emissions by 15–20%.”
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