| Abstract
| - A life cycle assessment has been done to compare thepotential environmental impacts of various gasoline blendsthat meet octane and vapor pressure specifications. Themain blending components of alkylate, cracked gasoline, andreformate have different octane and vapor pressurevalues as well as different potential environmental impacts.Because the octane and vapor pressure values arenonlinearly related to impacts, the results of this studyshow that some blends are better for the environment thanothers. To determine blending component compositions,simulations of a reformer were done at various operatingconditions. The reformate products of these simulationshad a wide range of octane values and potential environmentalimpacts. Results of the study indicate that for low-octane gasoline (95 Research Octane Number), lowerreformer temperatures and pressures generally decreasethe potential environmental impacts. However, differentresults are obtained for high-octane gasoline (98 RON),where increasing reformer temperatures and pressuresincrease the reformate octane values faster than the potentialenvironmental impacts. The higher octane values forreformate allow blends to have less reformate, and thereforehigh-octane gasoline can have lower potential environmentalimpacts when the reformer is operated at highertemperatures and pressures. In the blends studied,reformate and cracked gasoline have the highest totalimpacts, of which photochemical ozone creation is thelargest contributor (assuming all impact categories areequally weighted). Alkylate has a much lower total potentialenvironmental impact but does have higher impactvalues for human toxicity by ingestion, aquatic toxicity,terrestrial toxicity, and acidification. Therefore, dependingon environmental priorities, different gasoline blendsand operating conditions should be chosen to meet octaneand vapor pressure specifications.
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