Excellent synergy effect on preventing CH4 hydrate formation when glycine meets polyvinylcaprolactam

Abstract

The inhibitory performance of glycine and its synergistic potentiality for poly N-vinylcaprolactam (PVCap) was studied by evaluating subcooling temperature, induction time and crystal growth inhibition respectively. Glycine could not inhibit CH4 hydrate formation alone but it could enhance the inhibitory performance of PVCap. The subcooling temperature of PVCap increased by 4.1°C and the induction time also increased by 16-fold after blending the glycine with PVCap. Simultaneously, the performance of PVCap inhibiting hydrate crystal growth became more powerful in the presence of glycine. The rapid growth region of PVCap was totally avoided even at 13.5°C subcooling with the help of glycine, leading crystal growth rate decreasing by 80%. The biggest difference between glycine and common synergists was that 1.0% mass fraction glycine could equivalently replace PVCap in the same amount, leading 40.8% lower cost and 23.4% higher biodegradability. Furthermore, the relationship between outstanding synergistic effect of glycine and its hydrophilic structure was studied.