若干潜在煤直接液化溶剂特征及对煤的辅助液化作用

发布时间：2018-06-17 11:37

本文选题：煤直接液化 + 潜在溶剂　；参考：《中国科学院大学(中国科学院过程工程研究所)》2017年硕士论文

【摘要】：在煤直接液化工艺中,溶剂除了对煤粉的输送作用外,对煤还具有辅助液化的作用。大量研究表明,选用四氢萘、二氢菲、二氢蒽类氢化芳烃作溶剂,可有效增加煤的转化率和油收率。这类溶剂的适度芳香结构和氢化芳烃结构,对煤热解自由基和液化产物具有优秀的分散、溶解和供氢作用。然而,实际应用中,煤直接液化溶剂主要是液化工艺馏分油的加氢处理产物,补充溶剂常来源于石油加工或煤加工工艺馏分油及加氢处理产物。组成、结构复杂多样,对煤液化的辅助作用取决于原料组成和加工处理条件。论文基于中科院煤专项课题和中科合成油公司分级液化课题的要求,选择了 18个溶剂为潜在煤直接液化溶剂,对比研究了这些溶剂样品的相关物化特征,以及对煤的辅助液化作用。研究涉及的溶剂分三个系列(YLA、YLB和YLC)。YLA为石油芳烃油基系列,包括不同加氢深度的4个样品;YLB为加氢煤焦油基系列,包括1个全馏分和7个窄馏分样品;YLC为煤直接液化工艺油基系列,包括6个不同加氢深度样品。旨在认识石油基、煤焦油基和过程工艺油基溶剂的相关特点,为煤分级液化中试项目溶剂及溶剂制备工艺条件的筛选提供基础数据。结果表明,所选溶剂样品的物化特征,系列内差异较小,不同系列间有显著的差异。YLA系列起始样品馏程分布较高,随加氢次数增加,沸点分布曲线向低温区偏移。尽管YLB系列相邻窄馏分样品的沸程有明显重叠,沸点分布明显集中。YLC起始样品馏程分布较低,随着加氢空速的降低,沸点分布曲线向低温区偏移。YLA、YLB和YLC系列样品的(H/C)atomic分别为1.3-1.47、1.40-1.53和1.47-1.72。系列样品中族组成分布比较复杂,YLA系列起始样品中高聚芳环含量较高,与这一系列样品较高的馏程分布一致。随加氢深度的提高,高聚芳环含有明显降低。一般来说,无论是YLA系列还是YLC系列样品,随着加氢深度的提高,高聚芳环含量降低,单环、双环和环烷烃结构含量增加。推测氢化芳烃为加氢中间产物。YLC系列中,低馏分段样品中单环芳烃含量较高,高馏分段样品中链烷烃含量较高。在同比条件下,不同溶剂对煤的辅助液化作用表现出一定的差异。哈密煤在三个系列样品中的转化率在77%到86%范围。很遗憾,现有分析方法获得的溶剂族组成数据,难以作为关键参数评价或预测溶剂对煤的辅助液化作用。研究范围内,煤转化率和(H/C)atomic似乎有一定联系。
[Abstract]:In the direct coal liquefaction process, the solvent can not only transport coal powder, but also assist coal liquefaction. A large number of studies have shown that the conversion of coal and the oil yield can be increased effectively by using tetralin, phenanthrene and hydrogenated aromatics of dihydroanthracene as solvents. The moderate aromatic structure and hydrogenated aromatics structure of this kind of solvents have excellent dispersion, dissolution and hydrogen supply to coal pyrolytic free radicals and liquefaction products. However, in practical application, the direct coal liquefaction solvent is mainly the hydrotreating product of the liquefaction process distillate oil, and the supplementary solvent usually comes from the petroleum processing or the coal processing process distillate oil and the hydrotreating product. The composition and structure of coal liquefaction depend on the composition of raw materials and processing conditions. Based on the requirements of the coal project of the Chinese Academy of Sciences and the classified liquefaction project of the synthetic Oil Company of China, 18 solvents were selected as the potential direct liquefaction solvents, and the physicochemical characteristics of these solvent samples were compared and studied. And the auxiliary liquefaction of coal. The solvent involved in the study is divided into three series: YLAYLB and YLC.YLA are petroleum aromatics oil-based series, including four samples with different hydrogenation depth, YLB is hydrogenated coal tar base series, It consists of 1 whole fraction and 7 narrow fraction samples, which are oil base series of direct coal liquefaction process, including 6 samples with different hydrogenation depth. The purpose of this paper is to understand the characteristics of petroleum-based, coal-tar and process oil-based solvents, and to provide basic data for the screening of solvents and solvent preparation conditions for pilot projects of coal classification liquefaction. The results show that the physical and chemical characteristics of the selected solvent samples are relatively small within the series, and there are significant differences among the different series. The range distribution of the starting sample of Yla series is higher, and the boiling point distribution curve shifts to the low temperature region with the increase of hydrogenation times. Although the boiling range of the adjacent narrow fraction of YLB series is obviously overlapping, the boiling point distribution is obviously concentrated. The range distribution of the initial sample of YLC is lower, and with the decrease of hydrogenation space velocity, The distribution curve of boiling point shifts to the low temperature region. The H- / C ~ (-) atomic values of YLAA YLB and YLC series are 1.3-1.47 ~ 1.47 ~ 1.40 ~ 1.53 and 1.47-1.72, respectively. The group composition distribution of the series is relatively complex and the content of high polyaromatic rings in the starting samples of the Yla series is higher, which is consistent with the higher distillation range distribution of the series of samples. With the increase of hydrogenation depth, the content of high polyaromatic ring decreases obviously. Generally speaking, with the increase of hydrogenation depth, the content of high polyaromatic ring decreases, and the structure of single ring, double ring and cycloalkane increases with the increase of hydrogenation depth, both YLA and YLC series samples. It is inferred that hydrogenated aromatics are the intermediate products of hydrogenation. The content of monocyclic aromatic hydrocarbons is higher in the samples of lower fraction and higher in the samples of high fractions. Under the condition of the same year, the auxiliary liquefaction effect of different solvents on coal shows certain difference. The conversion of Hami coal in three series samples ranged from 77% to 86%. Unfortunately, it is difficult to evaluate or predict the auxiliary liquefaction of coal by solvent as a key parameter. Within the scope of the study, there seems to be a relationship between the coal conversion rate and the H / C _ (atomic) ratio.
【学位授予单位】：中国科学院大学(中国科学院过程工程研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ529.1

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