The effect of experimental conditions on methane hydrate formation by the use of single and dual impellers

Natural gas hydrates (NGH) are proposed as gas storage and transportation media owing to their high gas content and long-term stability of hydrate crystal structure at common refrigeration temperatures and atmospheric pressure. Technically feasible, cost efficient hydrate production is one of the crucial items of the whole chain of storage and transportation of gas by means of NGH technology. This study investigates the effects of types and number of impellers and baffles. Single impeller experiments showed that hydrate formation rates of rushton turbine (RT) experiments are always higher than hydrate formation rates of pitched blade turbines upward pumping (PBTU) experiments for all types of baffles but on the other side RT experiments consume more energy. Hydrate yield values are always higher in the RT experiments showing that although the duration of hydrate formation process lasts less compared to PBTU ones, the amount of water that is converted to gas hydrates is more in RT experiments. The same results observed also in dual impeller experiments with the objection that values were closer. In single impeller experiments only PBTU experiments formed hydrates for 3 h while in dual experiments formed PBTU with full baffle and RT with no baffle experiments indicating a serious heat transfer limitations for the other experiments. It should be mentioned that PBT is the same with PBTU since all mixed flow experiments worked in upward pumping