Inhibition of gas hydrate formation by means of chemical additives-I. Development of an experimental set-up for characterization of gas hydrate inhibitor efficiency with respect to flow properties and deposition

A high-pressure test wheel for flow simulation has been used for the specific purpose of studying gas hydrate formation and inhibition in hydrocarbon gas-water-oil systems. The stainless steel wheel, which could be rotated in a temperature controlled chamber at a constant angular velocity, was equipped with pressure (0-150 bar), temperature (-10-150°C) and torque sensors. The sensor signals were transferred to a real time PC-based data acquisition system. A video camera mounted on a perspex window on the wheel allowed recorded data to be correlated with the visual information obtained. Viscosity changes, hydrate initiation and agglomeration changes in hydrate macrostructure and deposits on the pipe wall were easily detected. The gas hydrate inhibiting properties of several chemical additives have been examined. The discouraging results obtained with some previously patented additives indicate that the rotating wheel represents a more conservative and realistic test method than those hitherto applied.