Continuous Addition Terpolymerization of Maleic Anhydride, Octadecyl Acrylate, and Docosyl Acrylate: Experimenting the Terpolymers as Pour Point Depressants for Waxy Crude Oils

Abstract

Owing to their large specific surface areas and excellent heat and mass transfer compared with those of conventional batch reactors, microreactors have been widely used in chemical industries. In this study, a strategy is proposed for precisely controlling the synthesis of comb-type terpolymers in a microreactor. Poly(octadecyl acrylate− docosyl acrylate−maleic anhydride) was investigated as a pour point depressant (PPD) for waxy crude oils. A terpolymer showing a high weight-average molecular weight (M w ) and low polydispersity index (PDI) was synthesized within 5 min compared with a conventional time-consuming batch reaction. Under the optimal conditions, the M w of the terpolymer reached 3.7 × 10 4 , and the PDI was 1.42. Notably, the pour point of the crude oil was reduced by 8 K at a PPD dosage of 1300 ppm. The polymerization kinetics revealed that the microreactor accelerated the polymerization. In contrast to the batch reactor, the microreactor exhibited better heat transfer, which avoided the generation of hot spots. Furthermore, the calculated Bodenstein number (Bo) revealed that the degrees of plug-flow deviation and backmixing are negatively correlated with the molecular weight distribution.