Abstract: A method of operating and an arrangement for a steam boiler system including a furnace and along a following flue gas channel a number of superheaters, a number of economizers, and at least one air preheater located in the flue gas channel downstream of the economizers, a fabric filter baghouse located in the flue gas channel downstream of the air preheater, and downstream of the fabric filter baghouse is located a selective catalytic reduction (SCR) system including an SCR reactor, a high pressure steam coil heater upstream of the SCR reactor and a gas-gas heat exchanger connected upstream and downstream of the SCR reactor to transfer heat from flue gas after the SCR reactor to the flue gas upstream of the high pressure steam coil heater.

Abstract: A fluidizing gas nozzle head suitable to be connected to a fluidizing gas feeding device of a fluidized bed reactor. The fluidizing gas nozzle head includes an inlet channel having a longitudinal axis, an inlet end, and a second end, the inlet end of the inlet channel being adapted to connect the inlet channel in vertical gas flow connection with the fluidizing gas feeding device, four outlet channels, each of the four outlet channels extending from a first end to an outlet end, and a gas distribution space having a bottom face and a ceiling opposite to the bottom face. The second end of the inlet channel and the first ends of the four outlet channels are connected to direct gas flow connection with the gas distribution space. Each of the first ends of the four outlet channels has a central point, which central points define a rectangle with two long sides and two short sides having an aspect ratio of at least 2:1.

Abstract: A combustor air bar grid for use within a fluidized bed reactor includes at least two main air collector bars in fluid communication with a source of fluidizing gas, a plurality of primary air bars that are transversal to the main air collector bars and arranged on the at least two main air collector bars such that the main air collector bars support them, and in fluid communication to at least two of the main air collector bars. The main air collector bars and the primary air bars define ash removal openings in the air bar grid and a plurality of fluidized nozzles are arranged to each of the primary air bars for fluidizing the bed reactor. A fluidized bed reactor includes such a combustor air bar grid.

Abstract: A bottom-supported boiler that includes a boiler pressure body having a rectangular horizontal cross section formed by joining four planar water tube walls pairwise together so as to form four corners with water tube walls being formed with fins welded between the water tubes, and a support construction including four vertical columns vertically supported to the ground. The vertical columns are arranged outside of the boiler pressure body so that adjacent to each of the corner corners is arranged one of the four vertical columns. Each of the vertical columns is directly connected with a rigid joint to a respective corner so that vertical loads of the boiler pressure body are balanced by the four vertical columns, and so that the water tube walls are supported from their sides by the four vertical columns so that the weight of the boiler pressure body is transferred through the vertical columns, and such that each of the four vertical columns is directly attached to a respective corner.

Abstract: An arrangement for controlling a flow of solid particles includes a vertical inlet pipe for directing solid particles downwards and having a bottom at a level L0, a first outlet chute and a second outlet chute in particle flow connection with the vertical inlet pipe and a fluidizing device for directing controlled first and second sub flows to the first and second outlet chutes. The arrangement includes a branch in particle flow connection with an opening on a side wall of the vertical inlet pipe for directing the first sub flow of solid particles to the first outlet chute and a horizontally extending intermediate pipe for directing the second sub flow of solid particles to the second outlet chute. The intermediate pipe includes at least one nozzle feeding fluidizing gas to the intermediate pipe and has a first end in particle flow connection with the bottom of the inlet pipe.

Abstract: A boiler construction includes a boiler pressure body having a bottom and a roof at a height H from the bottom and at least four planar watertube walls forming a polygonal horizontal cross section with at least four corner sections, and a rigid support steel structure, the boiler pressure body being supported to the rigid support steel structure at a height between the bottom and roof. A vertical corner column is attached exteriorly to at least four of the at least four corner sections at a height region between the bottom and roof, and the supporting of the boiler pressure body is provided by supporting each of the vertical corner columns to the rigid support steel structure at a height from 0.1 H to 0.9 H from the bottom so as to balance vertical loads of the boiler pressure body.

Abstract: A boiler system includes a support construction and a furnace supported to the support construction at a vertically middle section of the furnace, the furnace being enclosed by water tube walls having two side walls and two end walls, a roof and a bottom, the side walls having a total height (H) from the bottom to the roof. Each of the two side walls has a vertical upper portion that extends from the roof to a level of thirty to seventy percent of the height (H), a lower portion that extends from the bottom to a level of thirty to seventy percent of the height (H) and has a vertical upper portion, and an in downward direction outwards bent intermediate portion at a level between the upper portion of the side wall and the vertical upper portion of the lower portion of the side wall.

Abstract: A fluidized bed boiler plant and a method of preheating combustion gas in a fluidized bed boiler plant. The boiler plant includes a furnace and a combustion gas channel, and a water-steam cycle including an evaporator section, a superheater section including a last superheater and a steam turbine, and a superheating path for conveying steam from the evaporator section via the superheater section to the steam turbine, and a first combustion gas preheater. The fluidized bed boiler plant includes a second combustion gas preheater, a steam extraction line attached in flow connection with the second combustion gas preheater and with the superheating path in a location upstream of the last superheater for conveying steam from the superheating path to the second combustion gas preheater.

Abstract: A particle separator module and a heat exchange chamber module connectable to a circulating fluidized bed boiler. The particle separator module includes 2N vertically aligned steam tubes, N being an integer greater than one. Each of the vertically aligned steam tubes is attached to a boiler upper portion and extends downwards to a predetermined level. Each of the 2N vertically aligned steam tubes is attached to one of N first beams. Each of the N first beams is suspended to hang in a horizontal position at the predetermined level by two adjacent steam tubes of the 2N vertically aligned steam tubes. N second beams are attached in a horizontal position to the top surface of the heat exchange chamber module, which is arranged to be suspended from the particle separator module by having each of the N second beams suspended by two adjacent beams of the N first beams.

Abstract: A circulating fluidized bed boiler includes a rectangular furnace, which is horizontally enclosed by sidewalls, for combusting fuel and combustion gas and generating a stream of flue gas and particles. The sidewalls include first and second short sidewalls and first and second long sidewalls. Multiple particle separators are arranged on the side of each of the first and second long sidewalls for separating particles from the stream of flue gas and particles discharged from the furnace. Each of the particle separators includes a vertical gas outlet tube for discharging cleaned flue gas from the particle separator. A back pass arranged on the side of the second short sidewall of the furnace is horizontally enclosed by back pass walls. A horizontally extending cross over duct system is directly connected to the vertical gas outlet tubes of the particle separators for conducting the cleaned flue gas to the back pass.

Abstract: A watertube panel portion for a fluidized bed reactor and a corresponding method. The watertube panel portion includes multiple parallel metal tubes having a tube length L1, an outer surface, an original outer diameter OD1, and an original wall thickness WT1, and a circumferentially extending recess formed in a central portion of each of the tubes, between first and second end portions. The recess has a constant depth D that is less than the wall thickness WT1. The recess encircles the outer surface of the central portion of the metal tube. A circumferentially extending metal coating has a constant thickness of at most the depth D of the recess to blanket the recess of each of the multiple metal tubes. A fin is continuously welded between each pair of adjacent tubes.

Abstract: An arrangement for feeding ammonia containing fluid into an exhaust gas passage of a combustion plant includes a first fluid line connectable in flow connection with a source of an ammonia containing fluid. A second fluid line is in flow connection with a source of a dilution fluid. A control unit controls multiple valve members of a valve unit, each of the valve members having a first inlet in flow connection with the first fluid line, a second inlet in flow connection with the second fluid line and an outlet in flow connection with an outlet channel connected to the exhaust gas passage. The valve members are connected in parallel so that the outlet of each of the valve members is in flow connection with a common outlet channel.

Abstract: A tubular waterwall structure in a fluidized bed reaction chamber includes horizontally adjacent first and second portions forming a corner structure and constituted by vertical tubes and fins centrally attached to the tubes and having a first width. The first wall portion has an outermost tube next to the corner, an upper portion defining an upper vertical plane in an upper level range and a lower portion defining a lower (outwards) vertical plane in a lower level range. The lower portion has a refractory lining. The second wall portion is vertical and has an outermost tube next to the corner. The outermost tube of the second wall portion is in the lower level region connected to the outermost tube of the first wall portion by a planar lower beveled corner fin having a refractory lining and a width that is larger than the first width.

Abstract: A method of reducing sulfur dioxide emissions of a circulating fluidized bed boiler plant. A first stream of sulfur-containing carbonaceous fuel is fed at a first feeding rate to a furnace of the boiler. A second stream of calcium carbonate containing absorbent having a predetermined d50 particle size is fed at a second feeding rate to the furnace. Oxygen containing gas is fed to the furnace for fluidizing a bed of particles forming in the furnace. Fuel is combusted with the oxygen and the sulfur in the fuel is oxidized to sulfur dioxide. The calcium carbonate is calcined to calcium oxide in the furnace. A portion of the calcium oxide is used to sulfate a first portion of the sulfur dioxide to calcium sulfate in the furnace.

Abstract: A circulating fluidized bed boiler includes a rectangular furnace, which is horizontally enclosed by sidewalls, for combusting fuel and combustion gas and generating a stream of flue gas and particles. The sidewalls include first and second short sidewalls and first and second long sidewalls. Multiple particle separators are arranged on the side of each of the first and second long sidewalls for separating particles from the stream of flue gas and particles discharged from the furnace. Each of the particle separators includes a vertical gas outlet tube for discharging cleaned flue gas from the particle separator. A back pass arranged on the side of the second short sidewall of the furnace is horizontally enclosed by back pass walls. A horizontally extending cross over duct system is directly connected to the vertical gas outlet tubes of the particle separators for conducting the cleaned flue gas to the back pass.

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.