(556a) Comparison of Life-Cycle Carbon Footprint of Fischer-Tropsch Diesel Versus Ultra-Low Sulfur Diesel

The increasing availability and competitive prices of shale/natural gas in the United States are spurring much interest in monetization options. One of these options is gas-to-liquids (GTL) technology to produce transportation fuels. Comparisons are commonly made between petroleum-based fuels and Fischer-Tropsch diesel (FTD) produced via GTL based on technical performance and economics. Given the growing interest in environmental and sustainability issues, there is a need to also consider and compare the greenhouse gas (GHG) emissions associated with both petroleum- and GTL-based fuels. In this work, we present a well-to-wheel life cycle assessment (LCA) for GTL diesel for a hypothetical commercial-scale facility to be located in Texas using pipeline-quality natural gas and an LCA for Ultra Low Sulfur Diesel (ULSD) produced at a refinery along the Gulf Coast from crude oil imported from offshore countries. An approach is proposed for determining and allocating GHG for the various steps of the LCA. The appropriate design and environmental tools are discussed and evaluated. We explore the various building blocks from raw material acquisition and transport, conversion, fuel transport and end use using the life cycle framework to compare GTL fuels to ULSD.