Knowledge Management System Of Institute of process engineering,CAS
|关键词||低温煤热解油 分离 物性估算 热力学 酚|
低温热解作为煤炭高效利用的新型途径越来越受到关注，低温热解油作为热解的重要产品与高温热解油有较大的区别，开展低温热解油的利用研究意义重大。本论文针对煤热解油体系，通过结构-物性关系、热力学、新型分离方法、系统集成等方面的研究，建立了煤热解油的结构-物性关联模型、形成了高附加值产品（酚）的绿色分离方法、构建了分离流程，并对系统进行优化集成。主要研究内容如下：（1） 针对煤热解油体系中多苯环物质的组成特性，开发了以苯环为基础基团的物性估算方法（苯链法），新增加了苯链基团和取代基团。通过苯链法和传统J-R法沸点、临界性质计算值的平均相对误差比较，验证了苯链法的可靠性。在苯链法得到的临界性质值基础上，使用Riedel和Yamada-Gunn公式对密度进行计算，计算值与文献值吻合较好，平均相对误差在10 %以内。在物性估算基础上结合文献数据，建立煤热解油物性数据库，包括单组分物性、共沸物物性及相关物性分析表征方法。（2） 开发了两类胺基类新型萃取剂，分别为咪唑类和酰胺类萃取剂，上述物质能与酚形成氢键作用生成不溶于油相的低共熔溶剂（DES）使酚得到分离，脱除率在90 %以上。对上述DES相关物性进行系统测定，如熔点、密度、黏度，并探索了其随组成和温度的变化规律。考察了萃取剂结构的影响，并对关键影响因素如反应时间、反应温度、摩尔比等的影响规律进行研究，得到优化的反应条件。通过红外表征和Gaussian计算，验证了氢键理论及取代基的空间位阻效应。将上述两类萃取剂应用于两种实际油品，酚脱除率在85 %以上，选用烟酰胺对酚的分离实验进行公斤级放大。（3） 对待萃取物与萃取剂形成DES的新型分离体系进行热力学研究，提出此类过程的三元示意相图，并建立了相关分离理论，系统测定了邻、对、间甲酚-正己烷-咪唑的相平衡实验数据。使用NRTL和UNIQUAC方程对相平衡数据进行关联回归，通过模拟值与实验值比较选定NRTL方程对流程进行进一步优化并得到相关二元交互参数。利用Aspen Plus对上述分离过程进行模拟优化，最终得到优化的萃取级数和萃取剂加入量。在实验和模拟的基础之上，设计了两类萃取剂从煤热解油中分离酚类物质的具体流程。（4） 将酚类物质萃取剂设计的氢键理论应用于洗油中吲哚的分离，开发了卤素类离子液体萃取剂，对吲哚起到较好的萃取作用，其中BmimBF4萃取率在90 %以上，兼具较高的选择性。考察了吲哚初始浓度、萃取时间、体积比、萃取温度等因素对萃取过程的影响，并通过红外谱图、分子模拟和离子液体极性研究对分离机理进行探索，证实了氢键和极性的影响。BmimBF4可通过反萃取回收，回收率在90 %以上并保持较高萃取率。最后在实验和流程模拟基础上设计得到离子液体萃取分离洗油中吲哚的具体流程。
Low temperature coal pyrolysis, as new method for the high efficient and clean utilization of coal, has attracted more and more attention. As the important products of pyrolysis, there are important differences between low temperature and high temperature pyrolysis oil. It would be of great significance to develop efficient utilization way of low temperature pyrolysis oil. The studies of structure-physical property, thermodynamics, the new separation methods and system integration are carried out for coal pyrolysis oil system. And the structure-physical propertiy correlation model is established, the green separation methods of higher-value products (phenol) can be formed, the separation process is structured, the whole system was integrated and optimized. The main research contents are as follows:(1) The new group contribution method (benzene-chain method) that takes benzene ring as the fundamental groups was developed on the basis of the composition characters of abundant multi-benzene substances in coal pyrolysis oil system. And the benzene chain groups and substituent groups were added as the new groups of benzene chain method. The reliability of benzene chain method is verified through the average relative error comparison between the literature and calculated value of boiling point and critical properties using BC-C method and traditional J-R method. On the basis of the calculated properties above, the density value can be obtained through the calculation using Riedel and Yamada-Gunn equations. The calculated values are agreed well with literature values, and the average relative error is within 10%. The coal pyrolysis oil physics database is established based on the estimated properties and literature data, which include single-components, azeotrope components properties data and relevant properties analysis and characterization methods. (2) Two kinds of new extraction agents with amido groups are developed, they are imidazole compounds and amide compounds, respectively. Above compounds can form deep eutectic solvents with phenolic compounds due to the hydrogen-bond interaction formed between them. Phenolic compounds could be separated because of the infusibility of formed DESs in oil. And the phenol removal efficiencies are higher than 90%. The physical properties of the DESs are systematically measured, such as melting point, density, viscosity. And their change regularities with composition and temperature are explored as well. The influence of extraction agent structure to the extraction process is investigated, the effect laws of key influence factors, such as reaction temperature, reaction time, mole-ratio are studied, finally the optimized reaction conditions are obtained. The hydrogen-bonded theory and steric-hinerance effect of substituent groups are verified through the IR characterization and molecular simulation. Above developed extraction agents are applied in two kinds of actual oils with phenols removal efficiencies around 85%. A t last, nicotinamide is chosen as the amplification extraction agents to use in kilo-scale separation process successfully. (3) The thermodynamic study is carried out for the new separation systems that the extracts and extraction agents formed DESs. The concept ternary phase diagram of these processes is proposed, and the relevant separation theory is established. The phase equilibrium experiment data of o-cresol, p-cresol, and m-cresol-hexane-imidazole are systematically measured, and they are correlated and regressed using NRTL and UNIQUAC models. NRTL model is selected to optimize the technological process through the comparison between simulation value and experimental value. And the relevant binary interaction parameters are obtained. The simulation and optimization of obove separaton processes are processed using Aspen Plus, and optimized extraction stages and addition of extraction agent are got finally. Based on the simulations and experiments, the specific processes for the separation of phenolic compounds from coal pyrolysis oil using the two new extraction agents were designed.(4) The hydrogen-bonded design theory for the phenolic compounds extraction agents is applied in the separation of indole from wash oil. Halogenoid ionic liquids are developed as a new kind of extraction agent with excellent extraction ablity of indole. Among them, indole extraction efficiency of BmimBF4 reaches more than 90%, and with a rather high selectivity. The influence of indole initial concentration, extraction time, volume-ratio, extraction temperature on the extraction process are investigated to get corresponding change rule. The separation mechanism is explored through FT-IR spectra, molecular simulation and the study of ionic liquid polarity, and the results suggest that hydrogen bond and polarity both affect this process. BmimBF4 can be recycled by reextraction, with the recovery efficiency more than 90% and high extraction efficiency. Finally, the specific process of separating indole from wash oil using ionic liquid is designed on the basis of both process simulation and experiment.
|焦甜甜. 煤低温热解油高效分离及系统集成[D]. 北京. 中国科学院研究生院,2016.|