Synthesis of branched chitosan derivatives for demulsification and steel anti-corrosion performances investigation

Abstract

In the process of oil production, the existence of water inevitably brings numerous problems, such as the formation of emulsion and oil pipeline corrosion. It is an urgent need to develop multifunctional oilfield chemicals with greenness, demulsification and corrosion inhibition functions. In this study, we synthesized two eco-friendly branched chitosan derivatives (BH and CH), and investigated their demulsification and corrosion inhibition performance. Confocal laser micrographs revealed that BH and CH destabilized the water-in-oil emulsion through coalescence and flocculation, resulting in demulsification. The demulsification results showed that BH and CH at 500 mg∙L−1 removed up to 90.45% and 81.53% of the emulsified water, respectively. The dehydrated crude oil corroded the oil pipeline during transportation. The synthesized BH and CH were grafted quaternary ammonium groups and Schiff bases, which could adsorb onto iron surface to protect pipeline from corrosion. BH and CH at 500 mg∙L−1 inhibited the carbon steel corrosion by 85.70% and 83.56%, respectively from weight loss experiment in 8 wt% NaCl CO2-saturated solution at 60 ℃. Surface analysis techniques (SEM, EDX) and electrochemical techniques agreed with weight loss experimental results revealing effective corrosion inhibition. Experimental results indicated that both BH and CH showed satisfying demulsification and corrosion inhibition performances. It indicated that chitosan oligomer derivatives BH and CH showed satisfying application prospect in petrochemical industry.