Gasoline from wood via integrated gasification, synthesis, and methanol-to-gasoline technologies

Original publisher: Golden, Colo.: National Renewable Energy Laboratory, [2011] OCLC Number: (OCoLC)700934018 Subject: Biomass energy -- Research. Excerpt: ... can also be upgraded to larger molecules in the gasoline range. Because the alkylation step requires an isoparaffin to react with an olefin, additional steps, like isomerization, can be used to convert n-butane ( straight-chained ) to the iso form, which can then be reacted with olefins. The most common commercial alkylation processes are catalyzed by a strong acid, either hydrofluoric acid or sulfuric acid. While environmental and safety concerns with respect to the use of strong acid catalysts have prompted development of solid acid catalyst methods for alkylation units, only traditional alkylation units are considered in this study due to performance and cost data availability ( Hutson 1977 ). The unreacted C3 and C4 hydrocarbons from the alkylation unit are either separated from the heavier gasoline products in another column and sent to a storage tank for sale as LPG or returned to the stabilizer column where the alkylate joins the gasoline stream. If a separate column is used to separate the C3 and C4 hydrocarbons, then the alkylate is sent to a tank for storage and later blended with the other gasoline fractions. The bottoms product from the stabilizer is sent to a splitter column to separate the stabilized gasoline into light and heavy fractions. The light fraction exits the top of the column where it is condensed and sent to a storage tank. The heavy fraction could be sent to an isomerization reactor to convert 1,2,4,5-tetramethylbenzene ( durene ) into 1,2,3,5-tetramethylbenzene. The former product ( durene ) has a relatively high freezing point ( 77 ° F, 25 ° C ) and will crystallize in fuel systems if the concentration exceeds about 5 vol %. The isomer product has a lower freezing point. This study concluded that the isomerization reactor was unnecessary because of the dilution effect of add...