Research for structure and composition of coke on spent commercial residue hydrotreating catalysts along HDM bed
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摘要: 针对取自中石油某装置不同床层轴向位置的工业固定床渣油加氢脱金属废催化剂,采用元素分析、热重分析、X射线光电子能谱、傅里叶变换红外光谱和核磁共振碳谱等,研究了催化剂上沉积焦炭的结构组成特征参数。结果表明,不同轴向位置废催化剂上的焦炭具有某些共同特征,如相同的碳类型和官能团等,但其结构和组成各不相同。模拟建立了基于各种表征结果的焦炭结构组成模型,并利用可计算核磁共振波谱化学位移和预测核磁共振谱图的gNMR软件对所建立焦炭模型的精确性进行了验证,表明模型与实验结果具有很好的一致性。Abstract: The spent residue hydrotreating catalysts were taken out from the different HDM bed axial position of a fixed-bed residue hydrotreating reactor of Petro-China. The coke on spent catalysts were studied by the technologies such as EA, TG, XPS, FT-IR and 13C NMR to get the structure characteristics and parameters. The results showed that the coke on spent residue hydrotreating catalysts located on different beds positions share some characteristics such as the kind of coke, the functional group, but the structure and composition were different from each other. Based on the result of each characterization technique, chemical structure models of coke were established. In order to ensure the accuracy of the structures, a software called gNMR helped to calculate the chemical shifts and predict the NMR spectra of the structure models. The model structures can be corrected to match the experimental results through comparing experimental spectra and the predicted ones.
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Key words:
- residue hydrotreating catalysts /
- coke /
- 13C NMR /
- chemical structure model /
- gNMR
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Table 1 Basic information of catalysts
Catalyst No. Reactor No. Catalyst species Sampling location in bed HDM 1 1 Ch-B top HDM 2 1 Ch-B middle HDM 3 1 Ch-B bottom Table 2 Elemental contents of spent catalysts
No. Catalyst species Content w/% nH/nC H C N S HDM 1 Ch-B 0.89 10.40 0.21 1.66 1.02 HDM 2 Ch-B 1.39 19.42 0.35 6.73 0.85 HDM 3 Ch-B 1.04 10.05 0.20 2.95 1.23 Table 3 Attribution and distribution of different carbon in catalysts
HDM 1 HDM 2 HDM 3 energy attribution AT/% energy attribution AT/% energy attribution AT/% 284.56 C-C 53.55 284.52 C-C 60.13 284.58 C-C 56.66 285.16 C-H 34.28 285.06 C-H 21.21 285.10 C-H 25.54 286.10 C-N 5.14 285.85 C-N 4.05 286.14 C-N 4.66 287.00 C-S 7.03 260.08 C-S 14.59 286.55 C-S 13.15 Table 4 Functional groups of coke deposit on the spent catalysts[9]
FT-IR peak wavenumber σ/cm-1 Functional group Mode of vibration HDM 1 HDM 2 HDM 3 577 590 571 C-S ν 744 766 740 -CH2- γ 816 810 816 R-Ar-H δ 974 1130 980 H-C=C-H δ 1124 1080 1120 C-N ν 1628 1600 1620 Ar ν 2940 2930 2930 C-H ν 3334 3360 3400 N-H ν -
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