Inhibition Effect of Order Brassicales Plant Extract (BPE) on Methane Gas Hydrate Formation in a Gas Dominated System

Abstract

Problems related to gas hydrate formation abound in oil field operations due to deep offshore activities, leading to severe adverse effects and safety problems all of which add to operating cost (OPEX). Prevention of these problems is key. The use THIs and KHIs have been explored but has their disadvantages. Due to the alarming rate of environmental degradation via toxic substances, there is an urgent need for friendly alternatives for both humans and the environment. This study compares the use of Brassicales Extract (BPE) and Poly n-vinyl caprolactam (N-VCap) as gas hydrate inhibitors. The BPE was evaluated using a locally fabricated stainless pipe mini flow loop. Hydrate formation and inhibition experiments were carried out for a period of 120 minutes with pressure and temperature readings recorded every 2 minutes. A rapid decrease in pressure and sudden increase in temperature are pointers to hydrate formation in the constant volume batch process loop. Microsoft excel was used to generate plots relevant to hydrate formation and inhibition. The various pressure plots showed that the BPE performed better than the conventional in most weight percentages considered. Pressure decline and temperature increase was more regulated in the systems with BPE unlike in the uninhibited experiment. The Volume of gas used up in the BPE inhibited system were 23.3, 14.7, 16.7, 15.3 and 12.7% for 0.01-0.05wt% respectively while for N-VCap, the volume of gas used up for the same weight percentage were 24, 17.3,22, 10.7 and 29.3% at the end of the experiments. BPE has inhibition efficiency values of 69.3, 80.7, 78.07, 79.82 and 83.3% for 0.01-0.05wt% respectively while that of the synthetic inhibitor was 68.42, 77.2, 71.1, 86 and 61.4%. It is recommended that the BPE be developed for gas hydrate inhibition because it did very well and is environmentally friendly unlike the N-VCap which is a toxicant.