Synergistic performance of mixed agro-waste-based amino acids as kinetic hydrate inhibitors for natural gas hydrate control

Abstract

The formation of plugs and clogs in pipelines caused by low temperatures and high pressures during drilling and production of natural gas hydrates causes difficulties for the oil and gas sector. Different commercially available kinetic hydrate inhibitors (KHIs) are used to manage this problem; however, they have disadvantages such as toxicity, low biodegradability, and high cost. Through the use of microbiological techniques, this study attempted to synthesize mixed amino acids from agricultural waste to prevent the formation of natural gas hydrates. The performance of mixed agro-waste amino acids (MBL4) was compared to single amino acids (glycine, histidine, proline, and alanine that are major components of MBL4) and PVCap as a control group at dosage of 0.1 and 0.5 wt%. The onset temperature and subcooling were used to assess the performance of the inhibitors in this study, which used the constant cooling method in a stirred high-pressure autoclave at 100 bar. The addition of MBL4 at 0.5 wt% retarded the onset of hydrate formation and increased the subcooling significantly when compared to PVCap and the individual single amino acids, with onset temperature and subcooling of 7.20 °C and 11.67 °C, respectively. The performance of MBL4 is observed to increase from 0.1 to 0.5 wt% dosage concentration, and MBL4 outperformed individual amino acids and PVCap. Mixed agro-waste amino acids showed better performance when used as KHI due to synergism, and this finding can offer a long-lasting, cheaper, and more efficient way of controlling gas hydrate formation in the oil and gas industry.