Combining coal gasification, natural gas reforming, and external carbonless heat for efficient production of gasoline and diesel with CO2 capture and sequestration

Abstract

In this paper, several novel polygeneration systems are presented which convert natural gas, coal, and a carbonless heat source such as high-temperature helium to gasoline and diesel. The carbonless heat source drives a natural gas reforming reaction to produce hydrogen rich syngas, which is mixed with coal-derived syngas to produce a syngas blend ideal for the Fischer–Tropsch reaction. Simulations and techno-economic analyses performed for 16 different process configurations under a variety of market conditions indicate significant economic and environmental benefits. Using a combination of coal, gas, and carbonless heat, it is possible to reduce CO2 emissions (both direct and indirect) by 79% compared to a traditional coal-to-liquids process, and even achieve nearly zero CO2 emissions when carbon capture and sequestration technology is employed. Using a carbonless heat source, the direct fossil fuel consumption can be reduced up to 22% and achieve a carbon efficiency up to 72%. Market considerations for this analysis include prices of coal, gas, high-temperature helium, gasoline, and CO2 emission tax rates. The results indicate that coal-only systems are never the most economical choice, unless natural gas is more than 5 $/MMBtu.