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Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Plant and process for the looping-type combusƟŽn of solid carbon-containing fuels. Ref. CNR 10083 Assignee(s): CNR CNR InƐƟƚute: IRC Main Inventor: Osvalda Senneca Countries: EP, US Priority date: 08/09/2008 Abstract The present invenƟon refers to an innovaƟve concept of looping combusƟon of solid carbon-containing fuels (coals of ĚŝīĞƌĞŶƚ quality, solid residues from oil manufacture, biomasses, solid wastes of Ěŝīerent nature, etc.). The process produces a gaseous Ňow with an extremely high concenƚƌĂƟon of CO2, which is ready for capture and sequestƌĂƟon. CombusƟŽn of carbon is accomplished by the combined use of two reactors in which alternated ŽdžŝĚĂƟŽŶ and reducƟŽn steps are iterated. It does not require the use of oxygen carriers (metal/metal oxides or sulphate/sulphide), unlike other chemical looping combusƟon processes proposed for gaseous fuels. Background The CO2 produced by a carbon-containing fuel is present in combusƟŽn eŋƵents in assŽĐŝĂƟŽn with steam, nitrogen and excess oxygen. CO2 separĂƟŽn and concentrĂƟŽn is rather expensive. Chemical looping combusƟŽn processes have been developed to overcome this problem, but can be applied to gaseous fuels only and require the use of adĚŝƟŽnal oxygen carriers like metal/metal oxides or sulphate/sulphide. Chemical looping combusƟon of solid fuels is complex because it requires a preliminary gasiĮĐĂƟon stage. Technology The proposed technology is based on the experimental observĂƟŽn that carbon-containing solids exhibit a remarkable Ăĸnity for oxygen at moderate temperature, ĮdžŝŶŐ it in the form of oxidized surface complexes. Such oxides are stable at moderate temperature (up to 300-400°C) but can be removed as CO2 at higher temperatures. Thanks to this property, carbonaceous fuels are gasiĮed by alternated oxygen uptake and desorƉƟŽn without need of inorganic oxygen carriers. Advantages and ApplicaƟons 1. No preliminary gasiĮĐĂƟŽn of the solid fuel required. 2. No external carrier, like metal/metal oxides or sulphate/sulphide. 3. No problems caused by ineĸcient gas-solid contact. 4. The process can be carried out at moderate temperature and with small reĂĐƟŽn volumes. 5. Conceptually simple if compared to other chemical looping combusƟon processes. 6. Tunable for solid fuel combusƟŽn and gasiĮcĂƟŽn applicĂƟŽŶƐ͘ Development stage Proof of concept; laboratory tests on various types of carbon; process design calculĂƟons. 39