P. Rangsunvigit, K. Inkong, S. Kulprathipanja
Keywords: hydrate, gas storage, natural gas
Summary:Methane hydrates have been coined as an alternative for natural gas storage. Despite of advantages of the hydrate technology, attempts have been made to overcome the technology limitation including slow hydrate formation and formation conditions. Promoters either using a small amount of chemical or the addition of a third surface material were reported to be viable solutions. Fundamentally, understanding the effects of promoters on the methane hydrate formation are still of interest and will further assist in the technology development. This work explored the morphology of methane hydrates during the formation with different promoters, including tetrahydrofuran (THF), sodium dodecyl sulfate (SDS), methyl ester sulfonate (MES), and hollow silica (HS). Experiments in this work followed Inkong et al. . A specially designed crystallizer made of sapphire and control system were used to observe morphology during methane hydrate formation. A high speed camera was used to record the formation. Temperature and pressure were varied according to the amount of THF, SDS, MES or HS used in each experiment. The results show that the promoters accelerate the methane hydrate formation with different phenomena during the formation. The addition of THF with different formation temperature results in different hydrate formation morphology. With low temperature, the hydrates mainly form downwardly. However, at high temperature, the formation takes place in the opposite direction. Adding MES in the hydrate formation at high temperature changes the morphology of formation and significantly increases the formation rate. The synergistic effects between SDS and HS can be clearly observed from the morphology.