Kinetics of CO2 and methane hydrate formation: An experimental analysis in the bulk phase

Gas resources captured in the form of gas hydrates are by an order of magnitude larger than the resources available from conventional resources. In order to keep the CO2 footprint in the world as small as possible, the idea is to produce methane hydrates and sequestrate CO2 into hydrates in the same reservoir. In particular, the kinetics of the gas hydrate formation and dissociation is crucial to design an optimal method for this gas exchange process. In this work, the kinetics of gas hydrate formation in systems containing either carbon dioxide or methane has been studied extensively by experiments in the bulk phase. The crystallization process is subdivided into the nucleation and the actual crystal growth process. It was found that the crystallization process is influenced by the system agitation. The nucleation process can be accelerated by better mixing, higher supersaturation and the memory effect (water quality). Results show that the CO2 hydrate formation is about three times faster than the CH4 hydrate formation. This proves that the production of CH4 from hydrates and the (simultaneous) sequestration of CO2 in gas hydrates is not only favorable from the thermodynamic point of view but also from formation kinetic aspects. (C) 2010 Elsevier Ltd. All rights reserved.