Method and device for biomass combustion without carbon dioxide emission

A method for biomass combustion and simultaneous capture of CO2 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 CaCO3 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 CaCO3 contained in the second solids stream and separating a resulting CO2-containing stream from the calciner into a CO2 stream and a third solids stream;
• (f) sending the third solids stream to a fluidized bed, the fluidized bed being fluidized with steam or CO2;
• (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.