Abstract: A method of operating an oxycombustion circulating fluidized bed (CFB) boiler that includes a furnace having a grid at its bottom section, a solid material separator connected to an upper part of the furnace, and an external solid material handling system. Oxidant gas is introduced into the CFB boiler through the grid as fluidizing gas, the fluidizing gas including recirculating flue gas. Fuel material is introduced into the circulating fluidized bed. A sulfur reducing agent including CaCO3 is introduced into the circulating fluidized bed. Solid material is circulated out of the furnace and provides an external circulation of solid material via the external solid material handling system. The solid material is fluidized in the external solid material handling system by introducing a fluidizing medium including recirculating flue gas into the handling system. A predetermined amount of steam is introduced into the handling system as a component of the fluidizing medium.

Abstract: A particle separator assembly connectable to a fluidized reactor includes a vertical vortex chamber enclosed by water tube panel walls forming a polygonal horizontal cross section and a supporting structure of the water tube panel walls. The polygonal horizontal cross section has at least six corners and the supporting structure has at least one horizontally arranged circular beam arranged outside of the water tube panel walls and attached by radially extending fasteners to at least three of the water tube panel walls. The at least one circular beam forms a full circle, or the at least one circular beam forms a partial circle covering at least seventy-five percent of a full circle and has ends that are firmly attached to a rigid support construction.

Abstract: A method of controlling a circulating fluidized bed gasifier includes feeding first and second portions of particulate material to be gasified through inlets in a gasifier. Oxygen and steam are fed through a bottom grid into a lower portion of the gasifier to fluidize the bed. Product gas and entrained particles are discharged from an upper portion of the gasifier. Particles are separated from the product gas and a portion of the separated particles is returned to the lower portion. A portion of the returned particles is oxidized to generate heat. Heat and oxidizing products from the lower portion are transferred to the center portion to generate the product gas. A ratio of the first and second portions of particulate material to be gasified is determined on the basis of a measured temperature profile so as to control the vertical temperature distribution in the gasifier.

Abstract: Sulfurous fuel and CaCO3-containing sorbent are combusted in a furnace of a circulating fluidized bed boiler. A dry circulating fluidized bed scrubber includes a reactor with water and Ca(OH)2 feeds for converting SO2 in the exhaust gas to CaSO3 and CaSO4 and a dust separator in gas flow connection with the reactor. A discharge removes CaO-containing bottom ash from the furnace. A classifier classifies a portion of the removed CaO-containing bottom ash into coarse and finer portions. A fine ash channel conveys some of the finer bottom ash portion from the classifier to a grinder. A ground ash channel conveys some of the ground bottom ash portion from the grinder to a hydrator to hydrate CaO in the ash to Ca(OH)2. A hydrated ash channel conveys some of the Ca(OH)2 from the hydrator to the dry circulating fluidized bed scrubber as a sorbent.

Abstract: A scrubber for removing pollutant compounds from a gas stream. At least one gas channel introduces the gas stream to a lower portion of the scrubber. An inlet chamber directs the gas stream upwards to form a vertical gas stream. A constriction section has a vertical axis of symmetry and includes a centrally arranged venturi nozzle, and is above and in flow connection with an upper end of the inlet chamber for accelerating the vertical gas stream. A reaction chamber is arranged above and in flow connection with the constriction section. A reagent in the reaction chamber converts pollutant compounds in the gas stream to reaction products. A discharge channel in flow connection with the reaction chamber discharges gas and particles including the reaction products from the reaction chamber. A particle separator separates particles from the gas. A return channel recycles a portion of the particles to the reaction chamber.

Abstract: An expansion joint in a vertical channel suitable for conducting hot particles. The expansion joint includes an upper channel portion including a lower end portion with a lower edge. A lower channel portion is sealingly connected by a flexible element connected on an outer side of the vertical channel. The lower channel portion includes an upper end portion with a horizontally extending upper plane. In a predetermined vertical level range, the upper end portion telescopically overlaps the lower end portion in a spaced relationship, to permit relative axial and lateral movements of the upper channel portion and the lower channel portion, whereby the upper plane is at a higher level than the lower edge. A sealing ring, including mutually connected sealing blocks positioned on an outer circumference of the lower end portion, is arranged on the upper plane.

Abstract: A circulating fluidized bed boiler includes a furnace for combusting solid carbonaceous fuel in a fast fluidized bed. A solids separator is adjacent to a sidewall of the furnace and separates solids entrained with exhaust gas discharged via an outlet channel. A gas seal conveys at least a portion of the separated solids to a first fluidized bed heat exchange chamber that is arranged downstream of the gas seal and has internal heat exchange surfaces. A first lift channel has a lower end connected to a bottom portion of the first fluidized bed heat exchange chamber and an upper end connected to an upper end of a first return channel for discharging solids from the first fluidized bed heat exchange chamber and taking the cooled solids to a lower portion of the furnace. A second fluidized bed heat exchange chamber is arranged adjacent to a lower sidewall of the furnace.

Abstract: A fluidized bed boiler with a support construction for a particle separator. The fluidized bed boiler includes a bottom-supported furnace in which at least one particle separator with a support construction is in gas flow connection with an upper portion of the furnace and includes a furnace side portion, an outer portion opposite to the furnace side portion, and a conical lower portion. At least two bottom-supported downcomer pipes are in fluid connection with a steam drum and adjacent to the outer portion of the particle separator. The support construction includes a frame-like supporting member surrounding at least a portion of the conical lower portion, and an outboard portion of the supporting member is attached to the at least two downcomer pipes to support the at last one particle separator.

Abstract: An arrangement for gasifying solid fuel includes a gasification reactor for producing further oxidizable product gas from solid fuel and a gas treatment reactor arranged in a flow direction of the product gas in gas flow connection with the gasification reactor. The gas treatment reactor includes a supply for supplying oxygenous gas to the gas treatment reactor for partial oxidization of product gas and for thermal cracking thereof. A radiation heat exchange cooler for cooling the product gas is arranged in connection with the gas treatment reactor to solidify melt components in the product gas. A discharge connection is arranged in the lower portion of the radiation heat exchange cooler for removing solidified melt components from the radiation heat exchange cooler. A method of gasifying solid fuel in a gasification reactor is also presented.

Abstract: A method of recovering heat from bottom ash that is discharged from a combustion process in a furnace. Fuel and combustion air are fed into a furnace for combusting the fuel in order to generate heat energy to produce at least one of steam and hot water in a boiler arrangement, in which flue gases and bottom ash are generated. The bottom ash is discharged from the furnace. Heat is recovered from the flue gases. Heat is also recovered to a bottom ash cooling circuit from the bottom ash discharged from the furnace in order to utilize the recovered heat for preheating the combustion air in a heat exchanger. The heat exchanger is arranged in a combustion air heating circuit. Heat is exchanged from the bottom ash cooling circuit to the combustion air heating circuit.

Abstract: A thermal power boiler includes a furnace having a rear wall. A flue gas channel connected to the furnace includes a vertical back pass arranged on the rear wall side of the furnace. An ash hopper in the lower portion of the back pass has (i) a front wall, (ii) a rear wall, and (iii) two sidewalls. A pre-heater preheats combustion air and is provided with an inlet channel for flue gas connected to the preheater. The inlet channel has vertical portions, with an upper portion being attached to the lower portion of the back pass near the ash hopper. The inlet channel includes two adjacent channel portions connected to opposite sides of the back pass. One of the two portions is directly connected to the front wall of the ash hopper, and the other is directly connected to the rear wall of the ash hopper.

Abstract: A thermal power boiler includes a furnace enclosed by two short side walls and two long side walls, flue gas channels arranged above the furnace, a back pass and a supporting structure. The supporting structure includes a stationary bearing structure supported from below. The bearing structure includes multiple vertical pillars and a parallel main supporting beams supported by the vertical pillars, and a suspension structure, so that the furnace hangs from the bearing structure. The main supporting beams and the flue gas channels arranged above the furnace are parallel with each other and parallel with the short side walls. The main supporting beams are preferably arranged at least partially between the flue gas channels extending over the roof of the furnace.

Abstract: A fluidized bed reactor arrangement includes a bottom portion and a roof portion. A reaction chamber is defined by at least one side wall extending between the bottom portion and the roof portion. The at least one side wall includes a vertically extending portion having a lower end and a lower portion, which lower portion is inclined in such a manner that a cross section of the reaction chamber decreases towards the bottom portion. A heat exchange chamber, outside of the reaction chamber, is at the lower portion of the at least one side wall. The lower portion of the at least one side wall forms a partition wall between the heat exchange chamber and the reaction chamber. The heat exchange chamber extends from the partition wall to a rear wall of the heat exchange chamber.

Abstract: An evaporator surface structure of a circulating fluidized bed boiler having a furnace that is enclosed by sidewalls and has a bottom and a ceiling. The evaporator surface structure includes at least one vertical and separate evaporator surface unit that is spaced apart from the sidewalls of the furnace. The at least one evaporator surface unit (i) is formed of planar water tube panels that extend from the bottom of the furnace to the ceiling of the furnace, and (ii) consists of two cross-wise joined vertical water tube panels.

Abstract: A circulating fluidized bed boiler includes a rectangular furnace having multiple particle separators connected to an upper portion of each of a front wall and a back wall of the furnace. Each particle separator includes a gas outlet, and a flue gas duct system connected to the gas outlets for conducting cleaned flue gas to a back pass. The particle separators are arranged in pairs. Each pair includes a front separator arranged adjacent to the front wall and a back separator arranged adjacent to the back wall. The flue gas duct system includes cross over ducts, each duct connecting the gas outlet of a front separator of a pair of particle separators, across and over the furnace, to the gas outlet of the back separator of the same pair of particle separators, and to the back pass, which back pass is arranged on the back wall side of the furnace.

Abstract: A fluidized bed reactor includes a bottom portion, a roof portion, and side walls vertically extending between the bottom portion and the roof portion, forming a reaction chamber of the reactor. At least one side wall of the reaction chamber forms at least one vertical indentation in the reaction chamber, which indentation extends from the plane of the at least one side wall towards the reaction chamber. The indentation extending from the plane of the at least one side wall towards the reaction chamber is formed of a portion of the at least one side wall, protruding from the plane of the at least one side wall towards the reaction chamber, and the portion of the at least one side wall includes at least two substantially vertical indenting wall portions deviating from the plane of the at least one side wall at vertical lines within a distance from each other.

Abstract: A steam generation boiler having a reaction chamber formed by a bottom portion in a lower portion, a roof portion at an upper portion, and walls extending vertically between the bottom portion and the roof portion. The walls include vertical end walls having a tapering wall section that tapers symmetrically with respect to its middle axis towards the bottom portion, in which (i) a first group of steam pipes in the tapering wall section including steam pipes on both sides of the middle axis, pass at an angle with respect to the middle axis in a wall plane of the tapering wall section, and from the wall plane into the reaction chamber, and (ii) a second group of steam pipes arranged to pass to the bottom portion along the wall plane.

Abstract: An expansion joint in a vertical channel suitable for conducting hot particles. The expansion joint includes an upper channel portion including a lower end portion with a lower edge. A lower channel portion is sealingly connected by a flexible element connected on an outer side of the vertical channel. The lower channel portion includes an upper end portion with a horizontally extending upper plane. In a predetermined vertical level range, the upper end portion telescopically overlaps the lower end portion in a spaced relationship, to permit relative axial and lateral movements of the upper channel portion and the lower channel portion, whereby the upper plane is at a higher level than the lower edge. A sealing ring, including mutually connected sealing blocks positioned on an outer circumference of the lower end portion, is arranged on the upper plane.

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: A centrifugal separator assembly including a polygonal separator chamber formed of planar wall sections joined with each other to provide a substantially gas tight structure and having at least four pairs of planar opposite wall sections. The chamber includes a tapered portion formed by having a first inward bending in each of the wall sections. The tapered portion extends as a discharge channel for separated particles from the separator chamber, which discharge channel is formed of first and second pairs of opposite wall sections being perpendicular to each other. In the discharge channel for separated particles, the first pair of wall sections extends into the area between the second pair of wall sections.