Hydrate Formation and Deposition Rate Studies in a Gas-Dominant Flowloop

Gas hydrate formation and blockage is a critical engineering concern for the oil and gas industry. While many studies over the past two decades have focused on quantifying hydrate formation and slurry behaviour in oil-dominant systems, there is a dearth of information available with which to assess hydrate growth rate or blockage severity in gas-continuous systems where liquid water may exist in either annular or stratified flow. This investigation deploys a single-pass flowloop in Perth, Western Australia, which was designed to simulate a gas-dominant flow at laboratory scale. The flowloop has been deployed to study the formation and deposition of gas hydrate in systems with variable liquid holdup (1-10 vol%) and subcooling up to 20 K. The results demonstrate that, at high gas velocities, approximately 50% of the hydrate formed exists as a deposit on the wall; the remaining hydrate particles are distributed through the gas phase in flow. While the total hydrate formation rate increased directly with subcooling, the rate of deposition and wall build-up depended heavily on flow regime. The frequency and severity of sloughing were observed to increase with subcooling, where visual analysis from the sapphire window was used to estimate average slough size. The results provide critical input parameters to aid in the development of gas-dominant formation and deposition models within hydrodynamic simulation engines.