Review on the characteristics and advantages related to the use of flue-gas as CO2/N2 mixture for gas hydrate production

The present review proposes itself to be a collection of decades of literature data about flue-gas usage for gas hydrate production; the results reported here may promote future research on this still quite unexplored field. This paper will put on evidence the main features and advantages associated to the use of these mixtures in the aforementioned application. For instance, it emerges that flue-gas mixtures may address some critical challenges which currently make hydrate exploitation often unfeasible for large-scale industrial applications: they may contribute to solve some important issues related to CO2 usage in replacement processes. Among them, we highlight the presence of a narrow region between the equilibrium curves of methane and carbon dioxide and costs associated to the production of pure CO2. After a brief introduction, a description about common flue-gas composition was provided in Chapter 2; Chapter 3 then proposes a collection of phase boundary equilibrium values for binary CO2/N2 mixtures, both in presence and in absence of chemical additives used to promote or inhibit hydrate formation. Hydrate formation with flue-gas was then investigated in Chapter 4 to 7 for several different applications: carbon dioxide separation, selective recovery of main components in natural gas mixtures, storage of CO2 and methane recovery; this final one has been explained with the support of two further tables of literature data about CH4/CO2 and CH4/N2 equilibria.