Characterization of Macromolecular Structure Elements from a Green River Oil Shale, II. Characterization of Pyrolysis Products by 13C NMR, GC/MS, and FTIR

详细信息    查看全文

• 作者：Thomas H. Fletcher ; Ryan Gillis ; Jacob Adams ; Trent Hall ; Charles L. Mayne ; Mark S. Solum ; Ronald J. Pugmire
• 刊名：Energy & Fuels
• 出版年：2014
• 出版时间：May 15, 2014
• 年：2014
• 卷：28
• 期：5
• 页码：2959-2970
• 全文大小：625K
• 年卷期：v.28,no.5(May 15, 2014)
• ISSN：1520-5029

文摘

This paper is Part II of a study of the chemical structural components of the organic matter of oil shale in the Green River formation. Three sections of a well-characterized oil shale core from the Utah Green River formation were demineralized, and the resulting kerogen was pyrolyzed at 10 掳C/min in nitrogen at atmospheric pressure at temperatures up to 525 掳C. The pyrolysis products (light gas, tar, and char) were analyzed using ¹³C NMR, GC/MS, and (FTIR). Pyrolysis yields of 80% (daf basis) were achieved at these conditions, with 60% daf tar yield at the highest temperature. The solid-state NMR results indicate that the aromaticity of the kerogen char increased from 20% (at RT) to 80% during pyrolysis, with a corresponding decrease in the average aliphatic carbon chain length from 12 to less than 1. The average number of aromatic carbons per cluster increased from 12 to 20 in a narrow temperature window between 425 and 525 掳C, with an increase in the number of attachments per cluster from 6 to 8 in that same temperature window. Liquid-state NMR results of the condensed tars showed predominance of n-alkyl chains, with similar carbon aromaticities at each temperature. The alkyl chains were also observed in the GC/MS data. The light gases determined by FTIR were primarily CH₄, CO, and CO₂. The combination of gas, tar, and char yields and chemical structure analyses are valuable for modeling of oil shale processes based on chemical structure rather than based on empiricism.