Abstract: A method of controlling a boiler plant during a switchover period from an air-combustion mode to an oxygen-combustion mode. The method includes steps of feeding fuel into a furnace of the boiler plant at a rate determined by a fuel feeding scheme, feeding air into the furnace at a rate determined by a descending air feeding scheme, feeding substantially pure oxygen into the furnace at a rate determined by an ascending oxygen feeding scheme, and recirculating flue gas into the furnace at a rate determined by an ascending flue gas recirculating scheme. The fuel feeding scheme, the air feeding scheme and the oxygen feeding scheme are such that the fuel is combusted and the flue gas containing residual oxygen is produced. Also, the fuel feeding scheme, the air feeding scheme and the oxygen feeding scheme are such that the content of residual oxygen in the flue gas is, during at least a portion of the switchover period, greater than during any of the air-combustion mode and the oxygen-combustion mode.

Abstract: A method of desulfurizing flue gas in connection with oxy-combustion. A sulfur containing gas flow is introduced to a flue gas desulfurization arrangement having a spray tower at its top part and a reaction tank at its bottom part, in which the reaction tank contains liquid slurry having a surface level L. Sorbent-containing liquid slurry is sprayed to the sulfur containing gas flow. Sulfur-containing molecules are allowed to be absorbed into liquid slurry droplets. The liquid slurry droplets are allowed to enter the liquid slurry in the reaction tank. Oxygen containing gas is bubbled in the liquid slurry from a gas inlet header and nozzles in the reaction tank, in which the nozzles are arranged at a certain level in the reaction tank. Sulfur-containing particulates settle in the reaction tank.

Abstract: A method of controlling a boiler plant during a switchover period from an air-combustion mode to an oxygen-combustion mode. The method includes steps of feeding fuel into a furnace of the boiler plant at a rate determined by a fuel feeding scheme, feeding air into the furnace at a rate determined by a descending air feeding scheme, feeding substantially pure oxygen into the furnace at a rate determined by an ascending oxygen feeding scheme, and recirculating flue gas into the furnace at a rate determined by an ascending flue gas recirculating scheme. The fuel feeding scheme, the air feeding scheme and the oxygen feeding scheme are such that the fuel is combusted and the flue gas containing residual oxygen is produced. Also, the fuel feeding scheme, the air feeding scheme and the oxygen feeding scheme are such that the content of residual oxygen in the flue gas is, during at least a portion of the switchover period, greater than during any of the air-combustion mode and the oxygen-combustion mode.

Abstract: A method of combusting carbonaceous fuel in a combustion system. The combustion system includes a source of oxygen and a furnace.

Abstract: A method of and a plant for combusting carbonaceous fuel, the method including the steps of introducing particulate oxygen selective sorbent, such as a perovskite type material, into an adsorption reactor of the combustion plant to form a first particle bed in the adsorption reactor, fluidizing the first particle bed by an oxygen-containing first fluidizing gas to adsorb oxygen from the fluidizing gas to the sorbent, conveying oxygen-rich sorbent from the adsorption reactor to a combustion reactor of the combustion plant to form a second particle bed in the combustion reactor, fluidizing the second particle bed by an oxygen-deficient second fluidizing gas to desorb oxygen from the sorbent, so as to produce free oxygen gas, and introducing carbonaceous fuel into the combustion reactor to oxidize the fuel with the free oxygen gas.

Abstract: A method of increasing the power of a carbonaceous fuel combusting boiler system includes the steps of (a) feeding carbonaceous fuel into a furnace of the boiler system, (b) feeding oxidant gas into the furnace for combusting fuel to produce exhaust gas, (c) discharging the exhaust gas from the furnace via an exhaust gas channel, (d) conveying a stream of feedwater from a boiler economizer arranged in the exhaust gas channel to evaporating and superheating heat exchange surfaces arranged in the furnace and in the exhaust gas channel for converting the feedwater to superheated steam, (e) expanding the superheated steam in a high-pressure steam turbine for generating power, (f) extracting steam from the high-pressure steam turbine at a decreased rate for preheating the feedwater, (g) conveying steam from the high-pressure steam turbine at an increased rate to a reheater arranged in the exhaust gas channel for generating reheated steam, (h) expanding the reheated steam in an intermediate pressure steam turbine f

Abstract: A method of and an apparatus for capturing CO2 from flue gas emanating from a carbonaceous fuel combusting power plant, which includes a source of oxygen and a combustion chamber for combusting the fuel with oxygen and thereby producing flue gas that includes CO2, water and excess oxygen as its main components. At least a portion of the flue gas is compressed to a pressure higher than about sixty bar, the compressed flue gas is cooled in a primary CO2 separating unit for capturing a first portion of the CO2 by condensing it to produce a liquid CO2 stream and a high pressure vent gas stream that includes oxygen and excess CO2, the liquid CO2 stream is discharged from the power plant, and the high pressure vent gas stream is conducted to a secondary CO2 separating unit for capturing a second portion of the CO2 by adsorbing it to an adsorbing material.

Abstract: A method of and a power plant for generating power by combusting carbonaceous fuel with substantially pure oxygen, and a method of modifying a process of generating power by combusting carbonaceous fuel from combusting the fuel with air to combusting the fuel with substantially pure oxygen.

Abstract: Carbonaceous fuel is combusted with an oxidant gas in a furnace of a boiler system to generate power. Oxidant gas is fed into the furnace for combusting the fuel to produce exhaust gas, the exhaust gas is discharged from the furnace via an exhaust gas channel, a stream of feedwater is conveyed from a final economizer arranged in the exhaust gas channel to evaporating and superheating heat exchange surfaces arranged in the furnace and in the exhaust gas channel for converting the feedwater to superheated steam, the superheated steam is converted in a high-pressure steam turbine for generating power, a first portion of steam is extracted from the high-pressure steam turbine for preheating the feedwater, a second portion of steam is conveyed from the high-pressure steam turbine to reheating heat exchange surfaces arranged in the exhaust gas channel for generating reheated steam, and the reheated steam is expanded in an intermediate pressure steam turbine for generating power.

Abstract: A method of controlling a process of generating power in a power plant with a boiler by combusting carbonaceous fuel with substantially pure oxygen. At full load conditions, the method includes introducing a first carbonaceous fuel feed stream into a furnace, introducing a first substantially pure oxygen feed stream into the furnace for combusting the first carbonaceous fuel feed stream with the oxygen, and recirculating a portion of the exhaust gas discharged from the furnace at a first recirculation flow rate to the furnace, to form, together with the first substantially pure oxygen feed stream, a first inlet gas stream having a predetermined average oxygen content, thereby discharging exhaust gas from the furnace at a first discharge flow rate.

Abstract: A method of and a plant for combusting carbonaceous fuel, the method including the steps of introducing particulate oxygen selective sorbent, such as a perovskite type material, into an adsorption reactor of the combustion plant to form a first particle bed in the adsorption reactor, fluidizing the first particle bed by an oxygen-containing first fluidizing gas to adsorb oxygen from the fluidizing gas to the sorbent, conveying oxygen-rich sorbent from the adsorption reactor to a combustion reactor of the combustion plant to form a second particle bed in the combustion reactor, fluidizing the second particle bed by an oxygen-deficient second fluidizing gas to desorb oxygen from the sorbent, so as to produce free oxygen gas, and introducing carbonaceous fuel into the combustion reactor to oxidize the fuel with the free oxygen gas.

Abstract: A method of and a power plant for generating power by combusting carbonaceous fuel with substantially pure oxygen, and a method of modifying a process of generating power by combusting carbonaceous fuel from combusting the fuel with air to combusting the fuel with substantially pure oxygen.

Abstract: A method of and an apparatus for capturing CO2 from flue gas emanating from a carbonaceous fuel combusting power plant, which includes a source of oxygen and a combustion chamber for combusting the fuel with oxygen and thereby producing flue gas that includes CO2, water and excess oxygen as its main components. At least a portion of the flue gas is compressed to a pressure higher than about sixty bar, the compressed flue gas is cooled in a primary CO2 separating unit for capturing a first portion of the CO2 by condensing it to produce a liquid CO2 stream and a high pressure vent gas stream that includes oxygen and excess CO2, the liquid CO2 stream is discharged from the power plant, and the high pressure vent gas stream is conducted to a secondary CO2 separating unit for capturing a second portion of the CO2 by adsorbing it to an adsorbing material.