常用的从含蜡原料油中提取石蜡的生产工艺为溶剂脱蜡,因此确定含蜡原料油在有机溶剂中的热力学基础数据以及析出蜡晶的晶形晶貌十分重要。采用动态法测定了费托合成精制减三线油(简称减压馏分油)在甲苯、正己烷、甲基异丁基酮、丁酮、异丙醇以及丁酮-甲苯混合溶剂(丁酮、甲苯体积比为3∶1)中的溶解度。研究数据表明,减压馏分油在6种溶剂中的溶解度随温度升高而增加,在甲苯中的溶解度最大,在异丙醇中的溶解度最小。采用改进的Apelblat方程、简化的Van′tHoff方程和二项式方程关联溶解度数据,关联结果良好,所得模型方程可预测所测温度范围内减压馏分油在6种溶剂中的溶解度,其中二项式方程拟合效果最佳。使用修正的Van′tHoff模型,确定了减压馏分油与有机溶剂二元体系的溶解吉布斯自由能、溶解焓及溶解熵,结果表明减压馏分油在6种溶剂中的溶解过程均为非自发的吸热过程,溶解过程中体系的混乱度增加。使用偏光显微镜观察了减压馏分油中的蜡分子在6种溶剂中结晶形成的蜡晶形貌,结果表明蜡分子析出形成片状晶体,具有短程有序性,酮苯溶剂中蜡晶的径向尺寸最大,但仍不超过50μm。在丁酮-甲苯混合溶剂及甲基异丁基酮溶剂中析出的蜡晶径向尺寸较大且2种溶剂脱油效果较好。

The commonly used production process of paraffin from feedstock oil is solvent dewaxing, so it is very important to find out thethermodynamic basic data of feedstock oil in organic solvent and the crystalline morphology of wax crystals.The solubility of hydrofining of3rd vacuum side-cut foots oils obtained from Fischer- Tropsch synthesis (i.e. vacuum distillate) in Toluene, Methyl isobutyl ketone, 2Butanone, 2-Propaol and 2-Butanone-Toluene mixed solvents (3 ∶ 1) were measured by a dynamic method.The results show that the sol⁃ubility of the vacuum distillate in those 6 solvents all increases with the increase of temperature, with the greatest solubility in toluene andthe lowest solubility in 2-Propaol.The modified Apelblat equation, simplified Van′t Hoff equation and Polynomial equation were usedto correlate the experimental solubility data.The results indicate that the solubility data can be well correlated by these three models,andthe obtained model equation can predict the solubility of vacuum fractions in 6 solvents within the measured temperature range, with thebinomial equation fitting the best. The dissolution Gibbs energy, dissolution enthalpy and dissolution entropy of the binary system ofvacuum distillate oil and organic solventwere obtained on the basis of the modified Van′t Hoff model and the experimental data. The resultsshow that the dissolution process of vacuum distillate in the studied solvents is an endothermic and non-spontaneous process, and the con⁃fusion of the system increases during the dissolution. The morphology of wax crystals crystallized in 6 solvents were observed with a polari⁃zing microscope.The results show that the wax molecules precipitated to form flake crystals with short-range ordering. The wax crystalshave the largest radial dimension in the 2-Butanone-Toluene mixed solvents, but still not exceeding 50 μm. the wax crystals precipitate in2-Butanone-Toluene and Methyl isobutylketone have larger radial size and better deoilization effect.

0 引言

1 试验

   1.1 试验仪器

   1.2 试验试剂

   1.3 试验装置和方法

2 结果与讨论

   2.1 减压馏分油元素组成与化学组成分析

   2.2 准确性验证

   2.3 溶解度数据

   2.4 溶解热力学参数计算结果

   2.5 蜡晶在不同溶剂中析出的晶体形貌分析

   2.6 溶剂萃取结果分析

3 结论