Kinetics studies of methane hydrate formation and dissociation in the presence of cyclopentane

The work systematically investigates the kinetic of methane(CH4) hydrate formation in the presence of cyclopentane(CP)by measuring induction time, hydrate formation rate, and gas uptake. The results showed that there are two steps for CH4 hydrate formation in the presence of CP: Step 1, pure CP hydrate formation. Step 2, gas enters the empty cages of pure CP hydrates to form CP/CH4 mixed hydrates. Besides, the rapid hydrate formation rate and high CH4 uptake are observed from hydrate formation in this work. At the optimum conditions of 288.15 K and CP mole fractions of 5.6 mol%, the gas uptake and the time required for completion of hydrate formation are 131.80 mmol/mol H2O and 138 min, respectively. Relative to the highest reported gas uptake obtained in the presence of thermodynamic promoter (72.0 mmol/mol H2O), the value increased by 83%. More strikingly, the work shows that high gas uptake hydrates formed at relatively low temperatures can be stored and transported at relatively high temperatures, as high as 298.15 K, without significantly reducing the gas uptake, thereby providing one of the cost-effective methods for hydrate storage and transportation, that is forming hydrates at relatively low temperatures and storing and transporting hydrates at relatively high temperatures. Further, we proposed a schematic of the process chain of SNG(storing natural gas via solid hydrate) technology in vehicular and detailed discuss the current status of SNG technology development. It can be concluded that using the strategy that storage and transportation hydrates at a low-pressure condition instead of at ambient pressure (1.0 atm) may be a more realistic choice to industrialize SNG technology.