Assessment of Thermal Evolution of Kerogen Geopolymers with Their Structural Parameters Measured by Solid-State 13C NMR Spectroscopy

详细信息    查看全文

• 作者：Zhibin Wei ; Xiuxiang Gao ; Dajiang Zhang ; and Jiang Da
• 刊名：Energy & Fuels
• 出版年：2005
• 出版时间：January 2005
• 年：2005
• 卷：19
• 期：1
• 页码：240 - 250
• 全文大小：309K
• 年卷期：v.19,no.1(January 2005)
• ISSN：1520-5029

文摘

The sidebands in the solid-state ¹³C NMR spectra of 13 polycyclic aromatic hydrocarboncompounds associated with kerogen structure were suppressed with cross polarization (CP), magic-angle spinning (MAS), and total sideband suppression (TOSS). The chemical shift values of thesemodel compounds were obtained under various chemical circumstances, which were subsequentlyused to determine the chemical shifts of aliphatic and aromatic carbons in kerogen structure viaCP/MAS/TOSS ¹³C NMR measurements. Dipolar dephasing (DD) was used to obtain the spectraof nonprotonated carbon, discriminating protonated and nonprotonated carbons in the aromaticcluster. Consequently, the structural parameters for different carbons were characterized. High-resolution solid-state ¹³C NMR measurements were conducted on a suite of kerogen macromolecules isolated from source rocks originated from the Kuqa depression, Awati River, andKapusaliang River of the Tarim Basin in northwestern China to develop an NMR-associatedmethod for monitoring the thermal alteration of kerogens. These rocks covered a broad maturityrange, as indicated by the R_o values of 0.52%-1.81%. Our results suggest that the aromaticity(f_a) and aromatic cluster size (_b) are effective parameters for assessment of the thermal evolutionof kerogens that resulted from the geological heating process undergone in the ancient sediments.