A method of combusting carbonaceous fuel in a combustion system. The combustion system includes a source of oxygen and a furnace. The method includes the steps of (a) feeding fuel and combustion gas including oxygen and recycling gas into the furnace for combusting the fuel with the oxygen and producing exhaust gas that includes CO2, water and excess oxygen as its main components, (b) conducting the exhaust gas discharged from the furnace into a scrubber so as to remove pollutants from the exhaust gas, (c) dividing the exhaust gas into a first exhaust gas stream and a second exhaust gas stream, and conducting the second exhaust gas stream as a recycling gas stream into the furnace, (d) conducting the first exhaust gas stream into a CO2 purification and capturing unit (CPU) to produce one or more condensate streams, a purified liquid CO2 stream and a vent gas stream that includes remaining CO2, (e) discharging the purified liquid CO2 stream from the combustion system, (f) conducting the vent gas stream into an adsorption unit so as to adsorb compounds, including remaining CO2, from the vent gas stream to an adsorbing material and to produce a pass-through gas stream, and (g) regenerating the adsorbing material to produce a desorbed gas stream that includes at least a portion of the adsorbed compounds, and conducting at least a portion of the desorbed gas stream into the furnace.
A method of increasing the power of a carbonaceous fuel combusting boiler system. The method includes the steps of (a) feeding carbonaceous fuel (16) into a furnace (14) of the boiler plant at a fuel feeding rate, (b) feeding oxidant gas (18) into the furnace for combusting the fuel to produce exhaust gas, (c) discharging the exhaust gas from the furnace via an exhaust gas channel (20), (d) conveying a stream of feedwater from a boiler economizer (38) 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 (50) for generating power, (f) extracting steam (74) 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 (36) arranged in the exhaust gas channel for generating reheated steam, (h) expanding the reheated steam in an intermediate pressure steam turbine (52) for generating power, and (i) conveying the exhaust gas in the exhaust gas channel from the reheater through a boiler economizer to a gas heater (42). The method also includes increasing the heat exchange surface area of at least one of the reheater and the boiler economizer and/ or adding a high pressure economizer downstream of the boiler economizer and upstream of the gas heater.
F01K 13/02 - Controlling, e.g. stopping or starting
F01K 7/22 - Steam engine plants characterised by the use of specific types of enginePlants or engines characterised by their use of special steam systems, cycles or processesControl means specially adapted for such systems, cycles or processesUse of withdrawn or exhaust steam for feed-water heating the engines being only of turbine type the turbines having inter-stage steam heating
F01K 7/38 - Steam engine plants characterised by the use of specific types of enginePlants or engines characterised by their use of special steam systems, cycles or processesControl means specially adapted for such systems, cycles or processesUse of withdrawn or exhaust steam for feed-water heating the engines being of extraction or non-condensing typeUse of steam for feed-water heating the engines being of turbine type
F01K 7/40 - Use of two or more feed-water heaters in series
A method of combusting sulfur-containing fuel in a circulating fluidized bed boiler (12) includes the steps of (a) feeding sulfur-containing fuel into a furnace (14) of the circulating fluidized bed boiler, (b) combusting the fuel (16) with oxidant gas (20, 22) consisting essentially of pure oxygen and circulated exhaust gas, so as to form exhaust gas having carbon dioxide and water as its main components, and (c) feeding calcium carbonate (18) containing material into the furnace so as to capture sulfur dioxide into calcium sulfate in the furnace. The temperature in the furnace is maintained above 870 °C.
F23C 10/10 - Apparatus in which combustion takes place in a fluidised bed of fuel or other particles with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
F23L 7/00 - Supplying non-combustible liquids or gases, other than air, to the fire, e.g. oxygen, steam
F23C 9/00 - Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
F23J 7/00 - Arrangement of devices for supplying chemicals to fire
F23C 10/04 - Apparatus in which combustion takes place in a fluidised bed of fuel or other particles with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
4.
OXYFUEL COMBUSTING BOILER SYSTEM AND A METHOD OF GENERATING POWER BY USING THE BOILER SYSTEM
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. The oxidant gas can be a mixture of substantially pure oxygen and recycled exhaust gas, and the ratio of the first and second portions of steam can be controlled to obtain a desired flue gas temperature in the exhaust gas channel downstream of the final economizer.
F01K 7/24 - Control or safety means specially adapted therefor
F01K 7/38 - Steam engine plants characterised by the use of specific types of enginePlants or engines characterised by their use of special steam systems, cycles or processesControl means specially adapted for such systems, cycles or processesUse of withdrawn or exhaust steam for feed-water heating the engines being of extraction or non-condensing typeUse of steam for feed-water heating the engines being of turbine type
