The life-cycle greenhouse gas (GHG) emissions of alternative fuels that are capable of replacing conventional, petroleum-derived gasoline and diesel continue to be scrutinized for policy implementation. These alternative fuel technologies can also produce a number of value-adding nonfuel coproducts that require thorough and rigorous assessment in order to achieve an accurate life-cycle GHG emissions value. By using the gas to liquids (GTL) diesel pathway as a proxy for other alternative fuel pathways with coproducts, this paper examines how integration of coproduct analysis using the substitution method is possible within the existing framework and functionality of the GREET model.
View Article and Find Full Text PDFIn the next two decades, the U.S. refining industry will face significant changes resulting from a rapidly evolving domestic petroleum energy landscape.
View Article and Find Full Text PDFThis paper describes the development of (1) a formula correlating the variation in overall refinery energy efficiency with crude quality, refinery complexity, and product slate; and (2) a methodology for calculating energy and greenhouse gas (GHG) emission intensities and processing fuel shares of major U.S. refinery products.
View Article and Find Full Text PDFGas to liquids (GTL) products have the potential to replace petroleum-derived products, but the efficacy with which any sustainability goals can be achieved is dependent on the lifecycle impacts of the GTL pathway. Life cycle assessment (LCA) is an internationally established tool (with GHG emissions as a subset) to estimate these impacts. Although the International Standard Organization's ISO 14040 standard advocates the system boundary expansion method (also known as the "displacement method" or the "substitution method") for life-cycle analyses, application of this method for the GTL pathway has been limited until now because of the difficulty in quantifying potential products to be displaced by GTL coproducts.
View Article and Find Full Text PDFThe synthesis of a new series of ligands with a 1,8-dimethylnaphthalene backbone is reported, 1,8-(R2PCH2)2C10H6, where R = (t)Bu 1 (dbpn), (i)Pr 2 (dippn), Cy 3 (dchpn) and Ph 4 (dphpn). The ligand 1 is structurally characterised by X-ray crystallography. A comparative structural study of the respective (diphosphine)Pd(dba) and (diphosphine)PdCl2 complexes is carried out, comparing the X-ray crystal structures of complexes 6, 7, 8, 10, 11 and 12.
View Article and Find Full Text PDFRuthenacyclobutane decomposition, involving competitive beta-hydride transfer to Ru and reductive olefin elimination during ruthenium-catalyzed olefin metathesis, is predicted by density functional theory calculations and experimentally confirmed by propene and butene formation during degenerate Ru-methylidene-catalyzed metathesis of ethylene. The results provide new focus on the nature of ruthenium metathesis catalyst decomposition under catalytic conditions.
View Article and Find Full Text PDFThe synthesis and characterization of dimers and polymers, wherein two or more cages are linked, represent an important frontier in the chemistry of fullerene derivatives. A simple and novel method that requires no special apparatus has been developed for the dimerization of [70]fullerene to (C70)2. Upon grinding [70]fullerene in a mortar and pestle in the presence of K2CO3, five structural isomers of (C70)2 have been produced.
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