Inhibition effect of chain end modified polyvinyl caprolactam on methane hydrate formation

Injecting kinetic hydrate inhibitors is an effective method to prevent the blockage of natural gas hydrate pipelines. In this paper, based on the structure of polyvinyl caprolactam (PVCap), oxyethyl and ester groups are introduced into the molecular chain end of PVCap to synthesize a new kinetic hydrate inhibitor PVCap-XA1. The inhibition performance of PVCap-XA1 on the formation of methane hydrate was evaluated in a high-pressure constant-volume cell, and the effects of PVCap-XA1 on the structure and morphology of methane hydrate were studied by powder X-ray diffraction, Raman spectroscopy and scanning electron microscopy (Cryo-SEM). The results showed that PVCap-XA1 had better inhibition than PVCap under the same experimental conditions. Microscopic tests showed that the addition of PVCap-XA1 did not change the crystal structure of methane hydrate, but distort the crystal plane of methane hydrate, and reduced the ratio of IL/IS. Meanwhile, the addition of PVCap-XA1 makes the microscopic morphology of methane hydrate change from porous and orderly to denser, which was not conducive to the passage of gas. © 2022, Editorial Board of CIESC Journal. All right reserved.