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ENVIRONMENTAL IMPACTS OF HYDROCARBON EMISSIONS IN LIFE CYCLE ANALYSIS OF GASOLINE BLENDING OPTIONS
Citation:
Mata, T. M., R L. Smith*, D M. Young*, AND C. V. Costa. ENVIRONMENTAL IMPACTS OF HYDROCARBON EMISSIONS IN LIFE CYCLE ANALYSIS OF GASOLINE BLENDING OPTIONS. Presented at 4th NATO/CCMS Pilot Study Meeting on Clean Products and Processes, Oviedo, Spain, 5/6-11/2001.
Description:
Changes in gasoline specifications worldwide affect demand for all major gasoline-blending components. The purpose of this study is to compare different gasoline formulations based on the accounting of the environmental impacts due to hydrocarbon emissions during the gasoline production and marketing. Gasoline blending streams used to meet all the specifications are: reformate, alkylate, cracked gasoline and butane. The two most important variables to consider in the gasoline blending are the research octaine number (RON) and the Reid vapour pressure (RVP) which are subject to technical and environmental constrinats. This study considers two gasoline octane grades, the 95 and the 98 RON. Among these two gasoline grades several formulations will be compared, i.e., with a different content of butane, reformate, alkylate and cracked gasoline. In doing the several gasoline formulations it is important to meet the RVP requirements defined by the EU Fuels Directive. This study accounts the gasoline losses due to evaporation and leaks, using existing methods in the literature, and evaluates the potential environmental impacts, using the Waste Reduction (WAR) algorithm. It includes eight impact categories: human toxicity by ingestion and by dermal/inhalation routes, terrestrial toxicity, aquatic toxicity, photochemical oxidation, acidification, global warming and ozone depletion. This anlaysis includes the several steps in the gasoline life cycle: the manufacture, storage, loading in tank trucks, loading in tankers or barges, transit losses during the transportation of gasoline to service stations, storage at service stations and vehicles refuelling. This study also considers the variation of the operation conditions of the reforming process, to adjust yield versus octane number, using process simulation. The calculated values are good estimates of the real process allowing different aspects to be easily analysed. Several conclusions came from this study, concerning an environmental evaluation of the different gasoline options and formulations and about the operation conditions that should be used in the reforming process in order to meet the gasoline specifications.