Abstract: A method of and an apparatus for controlling the temperature of a fluidized bed reactor, comprising a separator for separating first solid particles from the fluidized bed reactor, a return duct for returning a first portion of the first solid particles to the fluidized bed reactor, a discharge duct for the discharge of a second portion of the first solid particles and an inlet duct for transferring second solid particles from a second fluidized bed reactor to the fluidized bed reactor, in which the return duct and the inlet duct share a common end portion for transferring a mixture of solid particles, formed of the first portion of the first solid particles and the second solid particles, to the fluidized bed reactor. The apparatus also preferably includes a fluidized mixing device for mixing the first portion of the solid particles and the second solid particles with each other.

Abstract: A separator construction, connectable to a fluidized bed boiler having a furnace, for circulating bed material and returning the material to the furnace. The separator construction includes walls, a ceiling, an inlet conduit, an outlet conduit in flow communication with a flue gas channel located above the separator, and a suspending device connecting the separator to a supporting structure in a building housing the boiler. The suspending device is formed of a frame arranged between the flue gas channel and the separator in connection with an upper circumference of the wall of the separator, and hanger rods or wires connecting the frame directly to the supporting structure.

Abstract: A boiler water cycle of a fluidized bed boiler, preferably, a supercritical once-through-unit (OTU) boiler, includes a drop leg, a number of horizontal inlet headers, substantially having a length of the length of a front wall of the furnace of the boiler, arranged below the furnace, and panels of water tubes of the front wall and a rear wall, extensions of the water tubes being directly connected to the inlet headers, wherein each inlet header is in flow communication with a drop leg by way of an inlet duct connected to the end of the inlet header. The inlet headers include a front wall chamber below the front wall of the furnace, a rear wall chamber arranged below the rear wall of the furnace, and at least one grid chamber below the center part of the furnace grid in a wind box of the fluidized bed boiler.

Abstract: A method of generating power by oxyfuel combustion. Carbonaceous fuel and oxidant gas are fed into a furnace. In a first operating mode, the oxidant gas includes a stream of substantially pure oxygen conveyed from an oxygen supply for combusting the fuel with the oxygen to produce exhaust gas including mainly carbon dioxide and water. The exhaust gas is discharged from the furnace and is divided into a recycling portion and an end portion. The recycling portion is recycled to the furnace. Heat is transferred from the end portion to the stream of substantially pure oxygen by circulating a liquid heat transfer medium in a passage between an exhaust gas cooler and an oxygen heater.

Abstract: A heat exchanger and a circulating fluidized bed boiler with a heat exchanger including a first fluidized bed heat exchange chamber and a second fluidized bed heat exchange chamber, arranged in connection with a furnace of the circulating fluidized bed boiler, a first inlet channel for introducing hot solids from a particle separator of the external circulation of the circulating fluidized bed boiler into the first heat exchange chamber, a second inlet channel for introducing solids to the second heat exchange chamber, a first discharge for removing a first portion of the cooled solids from the first heat exchange chamber to the second inlet channel and a second discharge for removing cooled solids from the second heat exchange chamber to the furnace, the heat exchange chamber including an inlet for introducing hot solids directly from the internal circulation of the furnace to the second heat exchange chamber.

Abstract: An oxyfuel combustion system for generating power that includes a furnace for combusting carbonaceous fuel and substantially pure oxygen to produce exhaust gas including mainly carbon dioxide and water. An exhaust gas channel system discharges the exhaust gas from the furnace. The exhaust gas channel system has an upstream channel, an outlet channel and a gas recycling channel. The upstream channel recycles a recycling portion of the exhaust gas through the recycling channel to the furnace, and conveys an end portion of the exhaust gas through the outlet channel for final processing. The upstream channel is divided between a first divider piece and a connecting piece into a first exhaust gas channel portion and a second exhaust gas channel portion. A gas-gas heat exchanger arranged in the first exhaust gas channel portion transfers heat from exhaust gas in the first exhaust gas channel portion to gas in the gas recycling channel.

Abstract: A method of combusting oil shale in a circulating fluidized bed boiler. Fuel, including oil shale, is introduced into a furnace of the circulating fluidized bed boiler, primary oxygenous gas is introduced through a bottom grid of the furnace, and secondary oxygenous gas is introduced to the furnace at a first level above the level of the bottom grid. The primary oxygenous gas is introduced to the furnace at a rate providing below the first level a fluidizing velocity of less than 2.5 m/s, and the primary and secondary oxygenous gases are introduced to the furnace in such a way that a circulating fluidized bed is formed, and the fluidizing velocity at the first level is less than 70% of the fluidizing velocity in the upper portion of the furnace.

Abstract: A method and an apparatus for gasifying carbonaceous material, in which (a) gasifying carbonaceous material is gasified in a gasification reactor of a gasification system to produce a product gas, (b) the product gas, ash particles entrained with the product gas, residual carbon, and gasified tar compounds are discharged from the gasification reactor to a product gas channel, (c) the product gas discharged from the gasification reactor is cooled using a gas cooler disposed along the product gas channel, so that the tar compounds are condensed to a liquid from that tends to stick to heat exchange surfaces of the gas cooler, (d) solid material including the ash particles and the residual carbon is separated from the gasification system, (e) the solid material separated from the gasification system is guided to an ash reactor, and oxygen-containing gas is supplied to the ash reactor, whereby the residual carbon in the solid material reacts with oxygen, and additional ash particles and exhaust gas are generated,

Abstract: A fluidized bed boiler plant and a method of combusting sulfurous fuel in the fluidized bed boiler plant, a furnace of which plant is provided with a fluidized bed of particles. Sulfurous fuel, CaCO3-containing sulphur-binding agent and combusting air are introduced to the bed of particles, whereby fuel burns and generates flue gases and the sulphur-binding agent calcinates to CaO and binds SO2 generated in the combustion. Energy is recovered to a heat exchange medium circulating in heat exchange tubes of a condensing heat exchanger arranged in a flue gas channel, and a water solution of acid condensing on outer surfaces is neutralized by mixing it in a mixing vessel to a CaO-containing ash from a plant, preferably, fly ash collected by a dust separator.

Abstract: A method of and an apparatus for gasifying carbonaceous material, the apparatus including a gasification reactor, to which oxygen-containing primary gas and secondary gasification gas are introduced, whereby a portion of the material to be gasified is gasified to product gas, residual carbon contained in the fly ash extracted from the product gas is combusted in a cyclone combustor, and the exhaust gas from the cyclone combustor is guided to above the bottom level of the gasification reactor to act as secondary gasification gas.

Abstract: A method of reducing sulfur dioxide emissions of a circulating fluidized bed boiler. Sulfur-containing carbonaceous fuel is fed to a furnace of the boiler, and calcium carbonate is fed to the furnace at a rate relative to the first stream such that the molar ratio of calcium in the second stream to sulfur in the first stream is at most about 1.0. The fuel is combined so that the sulfur is oxidized to form sulfur dioxide. The calcium carbonate is calcined to form calcium oxide and the calcium oxide is used to sulfate the sulfur dioxide to form calcium sulfate. Flue gas particles are separated using a hot loop separator, and the separated particles are returned to the furnace. A sulfur-reduction stage downstream of the furnace further reduces the sulfur content of the flue gases.

Abstract: A nozzle arrangement for a fluidized bed gasifier or combustor. The nozzle arrangement includes a nozzle piece attached to a nozzle tube for forming one entity with the nozzle tube, which nozzle piece includes a nozzle chamber and a horizontally extending nozzle channel ending to a blow opening of the nozzle. The nozzle chamber and nozzle channel are limited from above by a lid. The nozzle arrangement further includes a protecting cover attached outside the lid for minimizing cooling of the outer surface of the nozzle piece due to fluidizing gas blown through the nozzle into the fluidized bed gasifier or combustor.

Abstract: A method of combusting oil shale or fuel having similar properties as oil shale in a circulating fluidized bed boiler. The method includes the steps of (a) introducing fuel into a furnace of the circulating fluidized bed boiler, (b) introducing primary oxygenous gas through a bottom grid of the furance, and (c) introducing secondary oxygenous gas to the furnace at a first level above the level of the bottom grid. The primary oxygenous gas is introduced to the furnace at a rate providing below the first level a fluidizing velocity of less than 2.5 m/s, and the primary and secondary oxygenous gases are introduced to the furnace in such a way that the fluidizing velocity below the first level is less than 70% of the fluidizing velocity in the upper portion of the furnace.

Abstract: A grid construction for a fluidized bed reactor, the reactor including a reaction chamber defined by substantially vertical walls, in which a fluidized bed of solid particles is maintained, and a windbox under the reaction chamber, in a lower portion of the reactor. The grid construction is positioned between the reaction chamber and the windbox and includes (a) multiple continuous nozzle lines for distributing fluidizing gas from the windbox into the reaction chamber, for suspending the fluidized bed in the reaction chamber, and (b) continuous trenches between the nozzle lines. The nozzle lines include multiple gas outlets, having a main gas flow direction, at side faces of said nozzle lines, for directing fluidizing gas jets towards an adjacent trench.

Abstract: A boiler plant, including a combustion section, a heat exchange section including heat exchange surfaces, arranged above the combustion section and having a flow direction from the bottom upwards, and a stationary supporting structure. The combustion section and the heat exchange section are separate chambers, flexibly joined with each other, and the chambers are each separately hung from their upper part to the stationary supporting structure.

Abstract: A fluidized bed reactor, comprising a furnace, a heat exchange chamber, a substantially vertical discharge channel connected to the lower part of the heat exchange chamber for removing particulate material from the heat exchange chamber to the furnace, and a substantially vertical auxiliary channel for transferring particulate material from the heat exchange chamber to the furnace and from the furnace to the heat exchange chamber, the lower part of said auxiliary channel being provided with nozzles for fluidizing gas and with a flow conduit for connecting said auxiliary channel to the furnace and a flow conduit in the upper part for connecting said auxiliary channel to said heat exchange chamber. The furnace, heat exchange chamber, discharge channel and auxiliary channel preferably form an integrated structure having the discharge channel and the auxiliary channel adjacently arranged between the furnace and the heat exchange chamber.

Abstract: A fluidized bed reactor, comprising a furnace, a heat exchange chamber, a substantially vertical discharge channel connected to the lower part of the heat exchange chamber for removing particulate material from the heat exchange chamber to the furnace, and a substantially vertical auxiliary channel for transferring particulate material from the heat exchange chamber to the furnace and from the furnace to the heat exchange chamber, the lower part of said auxiliary channel being provided with nozzles for fluidizing gas and with a flow conduit for connecting said auxiliary channel to the furnace and a flow conduit in the upper part for connecting said auxiliary channel to said heat exchange chamber. The furnace, heat exchange chamber, discharge channel and auxiliary channel preferably form an integrated structure having the discharge channel and the auxiliary channel adjacently arranged between the furnace and the heat exchange chamber.

Abstract: A boiler plant, for example, a pulverized coal fired plant or a circulating fluidized bed boiler plant, comprising a combustion section, a heat exchange section arranged above the combustion section and containing heat exchange surfaces, in which heat exchange section the flow direction of the flue gas is from the bottom upwards, and a stationary supporting construction. In the boiler plant, the combustion section and the heat exchange section are separate chambers, flexibly joined with each other, and each chamber separately hung from the top part to a stationary supporting structure, preferably to its horizontal supporting planes.

Abstract: Method and apparatus for gasifying carbonaceous material, in which (a) product gas and ash, residual carbon a gasified tar compounds entrained therewith are discharged from a gasifying reactor to a product gas channel and cooled in a gas cooler, whereby tar compounds condense in a liquid state and tend to stick on heat surfaces; (b) solids containing ash particles and residual carbon separated from the gasification system, preferably from its product gas, are supplied to an ash reactor, in which the residual carbon reacts with oxygen and ash particles and exhaust gas is generated; and (c) ash particles are supplied to the gas cooler or upstream from the gas cooler, whereby the ash content entrained with the product gas increases and the sticking of condensing tar compounds on the heat surfaces decreases.

Abstract: An apparatus for pneumatically conveying particulate material containing reaction products of a high pressure reactor from a supply vessel at a pressure of at least two bar to a receiving vessel at a considerably lower pressure. The apparatus includes a conveyor line attached to the supply vessel, a collecting vessel between the conveyor line and the receiving vessel, the collecting vessel including (i) a discharge conduit for the carrier gas, (ii) a device for controlling the discharge velocity of the carrier gas from the collecting vessel, and (iii) a device for controlling the pressure of the material collected in the collecting vessel, and a device for conveying the material directly from the collecting vessel to the receiving vessel essentially at the same pressure as is prevailing in the receiving vessel.