CO2 sequestration from coal fired power plants

The paper takes into consideration a new approach for CO2 capture and transport, based on the formation of solid CO2 hydrates. Carbon dioxide sequestration from power plants can take advantage of the properties of gas hydrates. The formation and decomposition of hydrates from various N2-CO2 mixtures has been studied experimentally in a 2 l reactor, to determine the CO2 separation in terms of hydrate composition and residual CO2 content in the reacted gas. Carbon dioxide acts as a co-former for the production of hydrates containing nitrogen, besides CO2. The mixed hydrates that are obtained are less stable than simple CO2 hydrates. When CO2 content in the flue gas is higher than 30% by volume, the hydrates formed at 5 MPa are sufficiently concentrated (about 70% CO2) and carbon dioxide reduction in the reacted gas is acceptable. The application of a process based on hydrate formation could be especially interesting (for CO2 capture and transport) when connected to an oxy-coal combustion process; in this case the CO2 content in the flue gas is very high and the hydrate formation is greatly facilitated. © 2009 Elsevier Ltd. All rights reserved.