含芳香侧链梳形聚合物对沥青质聚集行为的影响

Effect of Comb-Type Copolymer with Aromatic Side Chains on Asphaltene Aggregation Behavior

选取了在聚马来酸酐-α-烯烃侧链接枝芳香基团(苯胺、萘胺及2-氨基苯并咪唑)的梳形聚合物(AMAC、NMAC和MACB)。利用UV-vis、浊度仪、动态光散射(DLS)、偏光显微镜分别表征了3种梳形聚合物对沥青质的初始沉淀点、粒径分布和聚集行为的影响。结果表明,添加质量浓度为50mg/L的同等接枝率的聚合物对沥青质的分散效果为:NMAC>AMAC>MACB;沥青质在模型油中的"初始沉淀点"最大增幅约为20%;平均粒径减小一半,且分布变窄;其微观聚集状态也由高聚集尺寸的絮凝态向低聚集尺寸的分散态转变。梳形聚合物能使沥青质更稳定地分散悬浮,对稠油的采输有现实的应用意义。

Due to the huge reserves all over the world, heavy crude oil has wide application prospects. However, because of its high density and high viscosity, the traditional production technologies are severely challenged. The asphaltene dispersant is one of the vital approaches to solve the aggregation of asphaltene and improve the flow ability of heavy crude oils. In this work, comb-type poly （maleic anhydride-co -α-olefin） （MAC） derivatives with phenyl, naphthyl and benzimidazole pendants （AMAC, NMAC and MACB） were synthesized. The effect of comb-polymers on the onset of asphaltene deposition, size distribution and aggregation behavior of asphaltenes in model oil were studied by means of UV-vis, turbidity meter, dynamic light scattering （DLS） and optical microscopy. The results show that the sequence of dispersion effect is： NMAC 〉 AMAC 〉 MACB, when their grafting ratio is similar and the dosage is 50 mg/L. For NMAC, the ＂onset of asphaltene deposition＂ is postponed by about 20%. The average size of aggregates was reduced by half and the size distribution was narrowed. The aggregation morphology of asphaltene was changed from the large-sized flocculated aggregates to the small-sized dispersed aggregates as observed by optical microscope. It indicates that the tttc conjugation interactions between aromatic pendant and asphaltene play an important role, but the hydrogen bonding between them is relatively weak which is resulted from the few heteroatoms in the periphery of aromatic rings ofasphaltene. Under the effect of these copolymers, asphaltene can be well dispersed in the oil, which indicating that they are good candidate additives for the recovery and transportation of heavy oil. Meanwhile, by knowing the interactions between the different aromatic pendants and asphaltene, the structure-performance relationship could be built. It indicates a practical direction for developing more efficient macromolecular asphaltene dispersants.