Phase equilibrium and separation of n-dodecane-toluene-phenol in low temperature coal tar

doi:10.11949/j.issn.0438-1157.20180032

Abstract

Abstract:

The group separation of low temperature coal tar (LTCT) is important for its effective utilization. With n-dodecane, toluene and phenol as model compounds, the liquid-liquid-equilibrium (LLE) of alkane-aromatics-phenol ternary system in LTCT were obtained by experimental method and Aspen Plus simulation. The LLE of typical ternary systems during separation of the mixture by N, N-dimethylformamide (DMF) water solution were also simulated. The results show that the ternary phase diagram simulated by Aspen Plus through UNIF-LL model fit well with experimental data. Toluene as a cosolvent promotes n-dodecane-toluene-phenol to be a homogeneous system. According to the solubility difference of n-dodecane, toluene and phenol in DMF and with the Hansen solubility parameters theory, n-dodecane and toluene can be separated successively from their homogeneous mixture by DMF in which different content of water were added to adjust the polarity of solvent. Based on the optimization of extraction temperature, solvent/oil ratio and water content in solvent, n-dodecane with 93.2% purity was separated by one stage extraction with DMF, and after phase separation, toluene with 93.4% purity was obtained by adding water weighted 30% of DMF to the extract phase at 303K, 1.5 solvent/oil ratio.

Key words: low temperature coal tar, liquid-liquid phase equilibria, Aspen Plus, simulation, solvent extraction, separation

摘要：

低温煤焦油组分的分离对其充分利用具有重要的作用。分别以正十二烷、甲苯和苯酚为模型化合物，采用实验和Aspen Plus模拟两种方法得到了低温煤焦油中脂肪烃-芳烃-酚类三元体系的液液平衡关系，并模拟了N，N-二甲基甲酰胺（DMF）水溶液萃取分离该体系时的典型三元相图。结果表明，Aspen Plus采用UNIF-LL法模拟得到的三元相图与实验测定结果吻合较好。甲苯在正十二烷-甲苯-苯酚体系中作为共溶溶剂，促使三元体系成为均相。根据正十二烷、甲苯和苯酚在DMF中的溶解性差异，结合Hansen溶度参数理论，通过在DMF中添加不同含量的H₂O以调节萃取剂的极性，可使正十二烷和甲苯依次从均相体系中分离。通过对萃取温度、剂油比和萃取剂含水量进行优化，最终在303.15 K，剂油比为1.5时，以DMF对模型油进行单级萃取，可以得到纯度为93.2%的正十二烷；相分离后向萃取相中添加DMF量30%的H₂O，可分离出纯度为93.4%的甲苯。

关键词: 低温煤焦油, 液-液相平衡, Aspen Plus, 模拟, 溶剂萃取, 分离

CLC Number:

TQ028.8

ZHANG Haiyong, LIU Qian, LIU Xingkun, ZHANG Xianglan, XIE Qiang, WANG Yonggang. Phase equilibrium and separation of n-dodecane-toluene-phenol in low temperature coal tar[J]. CIESC Journal, 2018, 69(8): 3479-3487.

张海永, 刘潜, 刘兴坤, 张香兰, 解强, 王永刚. 低温煤焦油中正十二烷-甲苯-苯酚的相平衡及分离[J]. 化工学报, 2018, 69(8): 3479-3487.

References 31

[1]	郭树才, 胡浩权. 煤化工工艺学[M]. 3版. 北京:化学工业出版社, 2012:6-8. GUO S C, HU H Q. Coal Chemical Technology[M]. 3rd ed. Beijing:Chemical Industry Press, 2012:6-8.
[2]	谷小会. 煤直接液化残渣的性质及利用现状[J]. 洁净煤技术, 2012, 18(3):63-66. GU X H. Properties and utilization of coal direct liquefaction residue[J]. Clean Coal Technology, 2012, 18(3):63-66.
[3]	王亚峰. 低温煤焦油组分分离及性质分析[J]. 长江大学学报(自科科学版), 2012, 9(5):26-28. WANG Y F. Separation and character analysis of low temperature coal tar composition[J]. Journal of Yangtze University(Natural Science Edition), 2012, 9(5):26-28.
[4]	丛兴顺. 煤焦油的分离技术及应用[J]. 枣庄学院学报, 2009, 26(2):69-72. CONG X S. Separation techniques and application of coal tar[J]. Journal of Zaozhuang University, 2009, 26(2):69-72.
[5]	赵璞, 裴贤丰, 王之正. 中低温煤焦油加工利用现状研究[J]. 煤质技术, 2016, (6):11-16. ZHAO P, PEI X F, WANG Z Z. Study on the present situation of medium/low temperature coal tar processing and utilization[J]. Coal Quality Technology, 2016, (6):11-16.
[6]	孙会青, 曲思建, 王利斌. 低温煤焦油生产加工利用的现状[J]. 洁净煤技术, 2008, 14(5):34-38. SUN H Q, QU S J, WANG L B. Present situation on production and processing use of low temperature coal tar[J]. Clean Coal Technology, 2008, 14(5):34-38.
[7]	张晓静. 中低温煤焦油加氢技术[J]. 煤炭学报, 2011, 36(5):840-844. ZHANG X J. Hydrogenating process for coal tar from mid-low-temperature coal carbonization[J]. Journal of China Coal Society, 2011, 36(5):840-844.
[8]	朱豫飞. 煤焦油加氢转化技术[J]. 洁净煤技术, 2014, 20(3):43-48. ZHU Y F. Hydro-conversion technologies of coal tar[J]. Clean Coal Technology, 2014, 20(3):43-48.
[9]	RADWAN G M, AL-MUHTASEB S A, FAHIM M A. Liquid-liquid equilibria for the extraction of aromatics from naphtha reformate by dimethylformamide/ethylene glycol mixed solvent[J]. Fluid Phase Equilibria, 1997, 129(1/2):175-186.
[10]	李宇, 乔海燕, 石薇薇, 等. 煤焦油萃取分离及产品性质[J]. 石油炼制与化工, 2017, 48(3):58-62. LI Y, QIAO H Y, SHI W W, et al. Coal tar separation by extraction and product properties[J]. Petroleum Processing and Petrochemicals, 2017, 48(3):58-62.
[11]	薛凤凤, 李冬, 张琳娜, 等. 煤基石脑油萃取脱芳复合萃取剂[J]. 化工进展, 2017, 36(8):2897-2902. XUE F F, LI D, ZHANG L N, et al. Composite extractant of liquid-liquid extraction aromatics for the coal-derived naphtha[J]. Chemical Industry and Engineering Progress, 2017, 36(8):2897-2902.
[12]	吴辉, 刘昌见, 肖聪. 四氢萘-正癸烷-二甲基亚砜液-液平衡数据的测定与关联[J]. 高校化学工程学报, 2016, 30(5):985-991. WU H, LIU C J, XIAO C. Determination and correlation of liquid-liquid equilibrium data for a tetranap-n-decane-dimethyl sulfoxide system[J]. Journal of Chemical Engineering of Chinese Universities, 2016, 30(5):985-991.
[13]	DONG H, YANG X, YUE G, et al. (Liquid + liquid) equilibria for benzene + cyclohexane +N, N-dimethylformamide + sodium thiocyanate[J]. Journal of Chemical Thermodynamics, 2013, 63:169-172.
[14]	SONG S, LIN C, YOU N. Phase equilibria Study of the (benzene+ cyclohexane+N, N-dimethylformamide+ potassium thiocyanate) quaternary systems[J]. Fluid Phase Equilibria, 2014, 376:154-158.
[15]	雷志刚, 周荣琪, 段占庭. NMP萃取精馏分离芳烃和非芳烃[J]. 高校化学工程学报, 2001, 15(2):183-186. LEI Z G, ZHOU R Q, DUAN Z T. Separation on the aromatics and paraffin by extractive distillation with NMP[J]. Journal of Chemical Engineering of Chinese Universities, 2001, 15(2):183-186.
[16]	杨玉敏, 胡洁, 郝丛, 等. 加盐萃取精馏分离邻二甲苯-间二甲苯的研究[J]. 现代化工, 2016, 36(4):173-175. YANG Y M, HU J, HAO C, et al. Separation of o-xylene and m-xylene by extractive distillation with salt[J]. Modern Chemical Industry, 2016, 36(4):173-175.
[17]	LIN Z, HOU Y, REN S, et al. Phase equilibria of phenol+toluene+ quaternary ammonium salts for the separation of phenols from oil with forming deep eutectic solvents[J]. Fluid Phase Equilibria, 2016, 429:67-75.
[18]	叶长燊, 林诚, 邱挺. N, N-二甲基甲酰胺-三氯甲烷-水体系液液相平衡数据的测定与关联[J]. 高校化学工程学报, 2009, 23(2):183-186. YE C S, LIN C, QIU T. Determination and correlation of liquid-liquid equilibrium data for the ternary system of DMF-CHCl3-H2O[J]. Journal of Chemical Engineering of Chinese Universities, 2009, 23(2):183-186.
[19]	王琳, 李入林, 孙林涛, 等. 超临界CO2与叔丁醇二元系统高压相平衡研究[J]. 高等学校化学学报, 2009, 30(8):1631-1635. WANG L, LI R L, SUN L T, et al. Studies on phase equilibrium of tertbutanol in supercritical CO2[J]. Chem. J. Chinese Universities, 2009, 30(8):1631-1635.
[20]	UEMASU I, KUSHIYAMA S. Selective separation of benzene from hydrocarbon mixtures via liquid-liquid extraction method using aqueous solutions of substituted cyclodextrins[J]. Fuel Processing Technology, 2004, 85(13):1519-1526.
[21]	马桂荣, 陈晓春, 于光认. 甲苯-环丁砜-硅醚三元体系液-液平衡数据的测定[J]. 北京化工大学学报, 2003, 30(3):5-9. MA G R, CHEN X C, YU G R. Determination of LLE data for toluene-hexamethyldisiloxane-sulfolane ternary system[J]. Journal of Beijing University of Chemical Technology, 2003, 30(3):5-9.
[22]	DEENADAYALU N, NGCONGO K C, LETCHER T M, et al. Liquid-liquid equilibria for ternary mixtures (an ionic liquid + benzene + heptane or hexadecane) at T=298.2 K and atmospheric pressure[J]. Journal of Chemical & Engineering Data, 2006, 52(1):988-991.
[23]	LIN W C, TSAI T H, LIN T Y, et al. Influence of the temperature on the liquid-liquid equilibria of heptane +toluene+sulfolane and heptane+m-xylene+ sulfolane[J]. Journal of Chemical & Engineering Data, 2008, 53(3):760-764.
[24]	姜广策, 张生娟, 王永刚, 等. 低温煤焦油中特定芳烃组分的选择性分离[J]. 化工学报, 2015, 66(6):2131-2138. JIANG G C, ZHANG S J, WANG Y G, et al. Selective separation of aromatic hydrocarbons from low temperature coal tar[J]. CIESC Journal, 2015, 66(6):2131-2138.
[25]	姜广策, 林雄超, 张生娟, 等. 基于Hansen溶度参数的煤直接液化残渣超临界萃取[J]. 高等学校化学学报, 2015, 36(3):544-550. JIANG G C, LIN X C, ZHANG S J, et al. Supercritical fluid extraction of direct coal liquefaction residue basing on Hansen solubility parameters[J]. Chem. J. Chinese Universities, 2015, 36(3):544-550.
[26]	姜广策. 基于溶度参数理论的煤基液体产物选择性萃取分离[D]. 北京:中国矿业大学, 2015. JIANG G C. Selective extraction of coal based liquid products based on the theory of solubility parameter[D]. Beijing:China University of Mining and Technology, 2015.
[27]	HANSEN C M. Hansen Solubility Parameters:A User's Handbook[M]. CRC Press, 2007.
[28]	刘光启, 马连湘, 刘杰. 化学化工物性数据手册•有机卷(增订版)[M]. 北京:化学工业出版社, 2013. LIU G Q, MA L X, LIU J. Chemical and Chemical Properties Data Book • Organic Volume (Upgraded)[M]. Beijing:Chemical Industry Press, 2013.
[29]	焦真, 马少玲, 王兵, 等. 用NRTL方程关联和预测离子液体-醇-水体系的液液相平衡[J]. 化工学报, 2006, 57(12):2801-2805. JIAO Z, MA S L, WANG B, et al. Correlation and prediction of liquid-liquid phase equilibrium of ionic liquid-alcohol-water systems with NRTL equation[J]. Journal of Chemical Industry and Engineering (China), 2006, 57(12):2801-2805.
[30]	MAGNUSSEN T, RASMUSSEN P, FREDENSLUND A. UNIFAC parameter table for prediction of liquid-liquid equilibriums[J]. Industrial & Engineering Chemistry Process Design & Development, 1981, 20(2):331-339.
[31]	许文林, 黄一波, 钱俊红, 等. 豆甾醇和β-谷甾醇在环己酮和正戊醇中的溶解特性研究[J]. 高校化学工程学报, 2003, 17(6):707-710. XU W L, HUANG Y B, QIAN J H, et al. Studies on the solubility of stigmasterol and β-sitosterol in cyclohexanone and n-pentanol[J]. Journal of Chemical Engineering of Chinese Universities, 2003, 17(6):707-710.