Synthesis and performance evaluation of polyolefin pour point depressant and paraffin inhibitor for high waxy crude oil
The polyolefin pour point depressant and anti wax agent POOS was synthesized from ternary copolymer P(ODA-co-ODE-co-SM),which was obtained from reaction of octadecyl acrylate(ODA),octadecene(ODE),and styrene(SM).The synthesis conditions of the ternary copolymer P(ODA-co-ODE-co-SM)were optimized,followed by evaluation on influence of POOS on the rheological properties,wax precipitation characteristics,microstructure,and anti wax effect of crude oil.The results showed that the optimal synthesis conditions of P(ODA-co-ODE-co-SM)were as follows:n(ODA)∶n(ODE)∶n(SM)=5∶3∶2,initiator benzoyl peroxide content(based on the total mass of octadecyl acrylate,octadecene and styrene)of 5‰,reaction temperature of 70℃,and reaction time of 8 h.The crude oil added with 200 mg/L POOS exhibited significant changes in rheological properties compared with that without POOS,displaying a drop of yield stress from 50.30 Pa to 2.95 Pa at 15℃,wax precipitation temperature from 31.33℃to 24.94℃,and pour point from 25℃to 15℃.Moreover,the crude oil added with POOS showed a wax prevention rate in the cold index test of 88.00%,and a wax prevention rate in the ring test of 83.70%,with the wax crystal morphology changing from needle like to circular crystal,more uneven wax crystal precipitation distribution,and multiple small wax crystals aggregated and precipitated to form a single aggregate.The addition of POOS effectively improved the dispersion morphology of wax crystals,inhibited the formation of network structures,and significantly improved the low-temperature flow effect of crude oil.
polyolefinspour point depression and wax preventionrheologywax precipitation characteristicsmicrostructureoil field chemicals
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