Synthesis of comb-like copolymers based on alkyl fumarates and their application as pour-point depressants for akshabulak crude oil

Abstract

Paraffin deposition causes numerous operational issues during the handling of waxy crude oil, and treatment with comb-structured polymeric additives can mitigate this problem. Copolymers based on dialkyl fumarates (DRFs) with long aliphatic side chains have shown potential for this purpose. However, there is no all-purpose agent that is efficient for all types of crude oil. This study investigates the effects of different copolymer characteristics, such as composition, molecular weight, and length of pending groups on the rheological behavior of Akshabulak crude oil upon additive treatment. The characteristics were varied by altering the comonomer type, polymerization technique, molar feed ratio of the comonomers, and composition of the DRFs. The fumarates and their copolymers were synthesized, and the products were characterized using Fourier-transform infrared (FTIR) and nuclear magnetic resonance spectroscopy. In addition, other parameters, such as intrinsic viscosity and molecular weight were determined. The efficiency of Akshabulak crude oil treatment with the synthesized copolymers was examined using pour-point measurements, rheoviscometry, and optical microscopy. The results indicated that dibehenyl fumarate–vinyl acetate with a molar feed ratio of 1:1.5 demonstrated good performance as a pour-point depressant.

Keywords

• Comb-like polymers
• Alkyl fumarate copolymers
• pour-point depressants
• Flow improvers
• Wax inhibitors