Patent ID: 8757072

Claim:
A method for biomass combustion and simultaneous capture of CO 2 generated in the combustion, the method comprising the steps of: (a) feeding biomass and air into a circulating fluidized bed combustor-carbonator; (b) effecting in the combustor-carbonator a biomass combustion and simultaneous CaO carbonation to generate CaCO 3 at a temperature between 550 and 700° C.; (c) separating a first stream of solids and gases from the combustor-carbonator in a first cyclone into a first solids stream and a second stream of solids and gases and recycling the first solids stream to the combustor-carbonator; (d) separating the second stream of solids and gases in a second cyclone into a second solids stream and a gas stream and leading the second solids stream to a calciner; (e) continuously calcining CaCO 3 contained in the second solids stream and separating a resulting CO 2 -containing stream from the calciner into a CO 2 stream and a third solids stream; (f) sending the third solids stream to a fluidized bed, the fluidized bed being fluidized with steam or CO 2 ; (g) continuously feeding fresh limestone to the fluidized bed; (h) continuously purging a fifth solids stream from the fluidized bed; and (i) removing a fourth solids stream from the fluidized bed and feeding the fourth solids stream to the combustor-carbonator, the fourth solids stream comprising between 5 and 20 times a molar flow of carbon fed with the biomass, and the combustor-carbonator containing an amount of CaO, in particle form, of at least 500 kg for every square meter cross-section of the combustor-carbonator, the CaO amount remaining stable in the fluidized bed.