Efficient Hydrate Plug Removal Using NaOH+ Cocoamidopropyl Dimethylamine+ MEG Compound in CO2-Containing Gas System

Natural gas hydrate plugging poses a significant challenge to pipeline flow assurance, particularly in systems containing CO2. In this study, a composite hydrate dissociation agent composed of cocoamidopropyl dimethylamine (CDA), monoethylene glycol (MEG), and NaOH was developed to enhance plug removal efficiency in CO2-rich natural gas systems. The plug removal agents, with mass ratios of CDA:MEG = 1:20 and NaOH:CDA:MEG =1:5:100, was evaluated under simulated pipeline conditions using rocking cells. Compared with our earlier work, experimental results demonstrated that the CO2 may cause the CDA ineffective, thereby significantly lowered the plug removal efficiency. Full-range slider movement can hardly be achieved within the usage of 20 vol%, corresponding to a grade A plug removal performance. The injection of 10–20 vol% of NaOH+CDA + MEG compound can effectively restore slider mobility. Notably, at 20 vol% dosage, the plug removal performance can reach grade A. The incorporation of NaOH was found to reduce CDA loss, thereby improving the dissociation efficiency and reducing the required dosage compared to the CDA + MEG binary system.