Gas hydrate inhibition: performance of an agro-waste based locally formulated inhibitor

Abstract

This paper compares the inhibitory capacity of two conventional kinetic hydrate inhibitors (KHIs), N-Vinylcaprolactam (N-VCap) and 2-Di(methylamino)ethyl Methacrylate (2-DMEM) with a Kinetic Hydrate Inhibitor developed locally from agro waste-based material. The Experiments were carried out using a 316 stainless steel laboratory mini flow loop, skid mounted on an external metal framework using 0.01-0.03 weight percentages of the various inhibitors. Plots of pressure versus time, temperature versus time and initial and final pressures showed the locally developed kinetic hydrate inhibitor (LDKHI) to be a better inhibitor with pressure decreasing from 150 psi to 122, 127 and 120 psi for 0.01 - 0.03 wt% respectively. Forthe same range of concentrations, N-VCap had pressure values of 114, 124 and 117 psi while that of 2-DMEM were 95, 120 and 116 psi, respectively. Optimum dosage of LDKHI was 127 psi at 0.02 wt%. For 0.01 to 0.03 wt% concentrations of all the inhibitors, LDKHI remained the best in minimizing the loop pressure drop as indicated by high volume of gas present in the loop at the end of 120 minutes. Inhibition efficiency versus weight percentages plot clearly showed that LDKHI performed better than the conventional kinetic inhibitors having inhibition efficiencies of 75.44, 79.82 and 73.68%. NV-Cap had values of 68.42, 77.19 and 71.05% and 2-DMEM inhibited system had values of 51.75, 73.68 and 70.18% for 0.01, 0.02 and 0.03 wt% respectively. These values for LDKHI are the highest compared to those of N-VCap and 2-DMEM respectively. The LDKHI is eco-friendly, biodegradable, readily available and water-soluble so it should be harnessed and considered for field trial.