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摘要: 用表面张力法研究了中东常压渣油热反应过程中正庚烷沥青质缔合性的变化。测定沥青质的不同浓度甲苯溶液的表面张力,利用溶液的临界胶束浓度表征沥青质的缔合性。定义蒸气压渗透法(VPO法)测得的沥青质平均分子量和表面张力法计算得到的平均分子量之比为沥青质的缔合度参数。结果表明,随着热反应的进行,在生焦诱导期内,沥青质的临界胶束浓度下降、沥青质缔合度参数增大,缔合性增强；达到生焦诱导期后临界胶束浓度上升、缔合度参数下降,缔合性下降。Abstract: The aggregating characteristics variation of asphaltenes of Middle East AR (ME-AR) during thermal reaction was studied. The aggregating characteristics of asphaltenes were demonstrated by the values of critical micelle concentrations (cmc). The cmc values of asphaltenes of ME-AR,40mim and 160min thermal reacted samples were 1.35×10-3mol·L-1,1.29×10-3mol·L-1 and 1.45×10-3mol·L-1. The aggregating tendency of asphaltenes was increasing during coke-induction period as thermal reaction going on, and was decreasing after that. Furthermore, the results of cmc showed that the asphaltene molecules were aggregated during VPO MW measurement. But asphaltenes were single when the solution concentrations were less than cmc. Hence the ratio of VPO MW to that gained by surface data of asphaltene solutions can be defined as aggregating parameter. The aggregating parameter was consistent with that of cmc. This paper manifested that asphaltenes tending to aggregating preferred to aggregating and coking during thermal reaction.
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Key words:
- residue /
- thermal reaction /
- asphaltenes /
- critical micelle concentration /
- aggregating characteristics
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