The Effect Of Side Chain Aromaticity And Spacer Length In Comb-type Copolymers On Rheological Properties Of High Wax Crude Oil

Due to the pipeline blocking caused by paraffin deposition has made crude oil transportation difficult, the thesis is aimed to study the assembly behavior between copolymer and paraffin, asphaltenes in crude oil, and the interaction mechanism of improvement flow ability.Liaohe crude oil is chosen as the research object, paraffin and asphaltenes were extracted from crude oil by ASTM standard, carbon distribution of paraffin was analyzed by GC-MS and1H NMR. To explore the interaction mechanism between oil components and chemical structure of copolymers, model oil was prepared according to the results of GC-MS, which contains mixture paraffins and asphaltenes extracted from Liaohe crude oil, of which mixture paraffins have the same carbon distribution with crude oil.Synthesize two kinds of comb-type copolymers via free radical polymerization and side chain grafting:one series is MAC, AMAC and NMAC containing different aromaticity pendants, to study the influence of side chain aromaticity on the assembly behavior between copolymer and oil components; another series is AMAC, EMAC and BMAC containing different spacer length, to study the effect of spacer length on the assembly behavior between benzene and asphaltene.1H NMR is used to characterize and the ratio of polar/non-polar is calculated. Rheometer, Polarized Light Microscopy, Differential Scanning Calorimetry are introduced to study the influence of copolymer on crystallization behavior of paraffins and asphaltenes aggregation condition of crude oil. The result shows that MAC, AMAC and NMAC all could improve crude oil’s flow ability, among which AMAC is the most effective. The reason is that, except for that long-chain alkane could co-crystallize with paraffin, the interaction between aromatic pendant and asphaltenes can weaken the packing structure of asphaltenes layers; NMAC shows the worst effect is because that steric hindrance is too much to interact with asphaltene molecules abundantly. Among AMAC, EMAC and BMAC, the longer the spacer, the better effect on improving the flow ability of crude oil.In conclusion, comb-type copolymer containing low aromaticity pendant (benzene ring) can further decrease the paraffin size, improve dispersity of asphaltenes; the longer the pendant spacer groups, benzene ring can more sufficiently interact with asphaltenes, thus further improve the flow ability. This thesis provides theoretical and experimental foundation for designing more efficient and novel copolymer pour point depressant, shows great potential economic value.