Methane Hydrate Formation and Dissociation in Oil-in-Water Emulsion

Abstract

The formation and dissociation of methane hydrates in oil-in-water emulsions have been studied. The phase equilibrium of methane hydrate in the emulsion has been investigated, and enthalpy of dissociation of methane hydrates in the emulsion has been calculated using the Clausius–Clapeyron equation based on the measured phase equilibrium data. The kinetics of hydrate formation has also been studied to observe the induction time of hydrate formation and hydrate formation rate. Further, the amount of gas consumed during hydrate formation has been calculated using the real gas equation.

Experimental and modeling study of kinetics for methane hydrate formation in a crude oil-in-water emulsion

“…Crude oil thermodynamically inhibits the formation of methane gas hydrate as observed in our previous work by Kakati et al (2014).…”

“…1 show a peak at 1410 cm -1 which is the effect of -C-C stretching in rings of aromatic components. SARA analysis of the crude oil had shown an appreciable weight percent of aromatics and asphaltenes (Kakati et al 2014) which augments the FTIR interpretation done here. A sharp peak at 1110-1000 cm -1 represents -C-N stretch in aliphatic amines to supplement the band for N-H at 3400-3250 cm -1 .…”

“…Our previous work described the experimental procedure in detail (Kakati et al 2014). The cell was filled with 120 mL of the prepared emulsion and methane gas was charged up to 11 MPa at 20°C.…”

“…-O-H and -C-O stretch around 1369 cm -1 indicates the presence of the carbonyl group which might be due to the carboxylic acid present in the crude oil. On the other hand, this could be indicating an ester functional group present instead of carboxylic acid to justify the low acid number per gram of KOH for crude oil observed by Kakati et al (2014). A weak band known as overtones showing at around 2040 cm -1 and out of plane-''oop'' bands from 900-675 cm -1 suggest aromatic groups.…”

“…The details of apparatus used in this study were mentioned in our previous work (Kakati et al 2014). Briefly, the high pressure autoclave consisted of a constant volume hydrate cell with a pressure rating up to 20.68 MPa.…”