Abstract:

In order to ensure the stable operation of the coal tar suspension bed hydrogenation unit, the asphaltene flocculation and the influencing factors of the raw material were studied. The coal tar asphalt initial floc point determination method was studied, and effects of composition molecular properties and structural parameters of heavy oil on asphaltene flocculation phenomenon in coal tar were analyzed. High temperature coal tar A, middle and low temperature coal tar >320 ℃ heavy fraction B and blending coal tar C（churning oil of A and B）were studied. Initial asphalt flocculation point of sample A, B, C was measured by photometer method. Samples were separated into saturates, aromatic, resin and asphaltene fractions. The coal tars and SARA were characterized by element analysis, molecular weight and NMR. The results showed that these three samples were unstable and asphaltene settled in varying degrees. The colloidal stability order was A>B>C. SARA composition and properties played a decisive role on colloidal stability together. Because sample A had highly condensed ring aromatic hydrocarbon, short and less side chains, large ratio of resin/ asphaltene, the aromaticity and molecular weight of SARA were distribution continuously, so asphaltene dispersion was good. Asphaltene flocculation happened extensively of sample C because of the mismatching of compositions and characters of sample A and B.

Key words: Coal tar, Asphaltene, Colloid stability, Flocculation

摘要： 为保障煤焦油悬浮床加氢装置的稳定操作，需对原料的沥青质絮凝现象及影响因素进行研究。研究了煤焦油沥青质初始絮凝点测定方法、四组分组成性质及重油分子结构参数对煤焦油中沥青质絮凝现象的影响。以一种高温焦油A、一种中低温焦油（大于320 ℃重油）B和两者混合油C为试样，采用光度计法测量焦油样品A、B、C的沥青质初始絮凝点。将煤焦油样品分离为饱和分、芳香分、胶质和沥青质四个组分，采用元素分析、相对分子质量测定、核磁共振H谱等分析手段，对样品性质和平均分子结构进行表征。结果表明，三种焦油样品均有不同程度的沥青质絮凝情况，其胶体稳定性为：A>B>C。四组分组成和性质共同决定样品的胶体稳定性。A样品因为具有高度缩合的稠环芳烃，侧链短且少，m(胶质)/m(沥青质)比值大，各组分芳香度、相对分子质量等性质连续分布，所以沥青质在芳香分和胶质中的分散情况较好，体系相对最稳定。A、B样品组成和性质差异大,导致二者不能很好相溶,因此混合焦油C样品胶体稳定性差。

关键词: 煤焦油, 沥青质, 胶体稳定性, 絮凝