(281d) Nucleation and Agglomeration of Hydrate Particles in Gas-Liquid Multiphase Flow Systems

In recent years, gas hydrate has been a research hotspot in the fields of CO₂ capture, refrigeration and oil/gas flow assurance and so on. Many researchers are focusing on the nucleation and agglomeration properties of gas hydrate, which are of great significance to the hydrate application and risk management. In this work, hydrate nucleation and agglomeration properties in gas-liquid multiphase flow systems were investigated using a high pressure flow loop. By adjusting the gas and liquid flow rates, four different flow patterns were obtained during the experiments, including stratified flow, bubble flow, slug flow and annular flow. The hydrate formation critical driving force, water conversion rate, hydrate growth rate and the hydrate agglomeration degree in different flow patterns were compared. The critical driving force and water conversion rate showed the same trends in different flow patterns, which from high to low in order was: slug flow, bubble flow, stratified flow and annular flow. The order of hydrate growth rate in different flow patterns from high to low was: bubble flow, slug flow, stratified flow and annular flow. According to the above comparison and analysis, it is harder for hydrate to nucleate in slug flow and bubble flow conditions, while the formation amount and growth rate in these two flow patterns are larger. However, the opposite case occurred in the stratified flow and annular flow. In addition, two methods were proposed based on the hydrate particle chord length distributions to estimate the hydrate agglomeration degree. The calculation results showed that the hydrate agglomeration degree from high to low in order was: slug flow, stratified flow, bubble flow and annular flow.