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.

A supporting beam arrangement (14) for supporting a flue gas duct (10) to a support frame (16) of the flue gas duct. The supporting beam arrangement comprises two horizontal first supporting beams (18) that are parallel and on two opposite sides of the flue gas duct (10) and separated by a distance from the flue gas duct, and further are connected to the support frame (16). The supporting beam arrangement (14) comprises a horizontal second supporting beam (20) defining two opposite ends (22) that are supported to the first supporting beams (18), the second supporting beam extending through the flue gas duct (10) that is supported to the second supporting beam. At least one or each one of the first supporting beams comprises an opening (24), in which opening one of the two opposite ends (22) of the second supporting beam is placed to rest on the first supporting beam (18). A power boiler (50) comprises the supporting beam arrangement (14), the flue gas duct (10) and the support frame (16).

A heat exchanger (10) comprising a first heat transfer tube (100) having a first primary straight part (101) and a first secondary straight part (103), the straight parts (101, 103) extending parallel in a first plane (P) in a longitudinal direction (di). The heat exchanger (10) comprises a first primary bond part (510) having a first primary surface (511), an opposite first secondary surface (512) and a first tertiary surface (513), the first tertiary surface (513) extending from the first primary surface (511) to the first secondary surface (512). On the first tertiary surface (513), a first primary hole (514) and a first secondary hole (515), are provided, both extending through the first primary bond part (510) in the longitudinal direction (d.sub.l). The heat exchanger (10) comprises a first secondary bond part (520) having a second primary hole (524) and a second secondary hole (525), both extending through the first secondary bond part (520) in the longitudinal direction (d.sub.l) on a second tertiary surface (523) from a second primary surface (521) to a second secondary surface (522). The first primary bond part (510) has been welded to the first secondary bond part (520) to form a first primary bond (530) that bonds parts of the first heat exchanger tube (100). Thus, the first primary bond (530) limits a first primary aperture (533) and a first secondary aperture (534) formed by the holes (514, 515, 524, 525), wherein straight parts (101, 103) extend through the first primary bond (530) via the apertures (533, 534).

An expansion joint for a solids return system includes a female joint portion, a male joint portion received by the female joint portion, the male joint portion and the female joint portion forming a lateral breach therebetween, a double rope seal positioned within the lateral breach, the double rope seal being configured to accommodate relative lateral movement between the female joint portion and the male joint portion, and an insulating pillow received about the male joint portion and abutting a distal end surface of the female joint portion, the insulating pillow being configured to accommodate relative axial movement between the female joint portion and the male joint portion.

A supporting beam arrangement (14) for supporting a flue gas duct (10) to a support frame (16) of the flue gas duct. The supporting beam arrangement comprises two horizontal first supporting beams (18) that are parallel and on two opposite sides of the flue gas duct (10) and separated by a distance from the flue gas duct, and further are connected to the support frame (16). The supporting beam arrangement (14) comprises a horizontal second supporting beam (20) defining two opposite ends (22) that are supported to the first supporting beams (18), the second supporting beam extending through the flue gas duct (10) that is supported to the second supporting beam. At least one or each one of the first supporting beams comprises an opening (24), in which opening one of the two opposite ends (22) of the second supporting beam is placed to rest on the first supporting beam (18). A power boiler (50) comprises the supporting beam arrangement (14), the flue gas duct (10) and the support frame (16).

The solution comprises a method of and a system for maintaining steam temperature and therefore electricity production efficiency with decreased loads of a steam turbine power plant comprising a fluidized bed boiler (12) and a fluidized bed superheater (2) adapted to superheat steam supplied to a steam turbine (3). According to the solution, the steam temperature may be maintained by providing, outside a furnace (10), additional heating to the fluidized bed material in its outer circulation, thereby increasing the amount of thermal energy available in the fluidized bed material to be transferred in the fluidized bed superheater (2) to the steam supplied to the steam turbine (3). Such additional heating may be performed by selectably supplying combustible gas with nozzles (111) into and/or burned with a burner in or in the vicinity of the fluidized bed material outside the furnace (10). As an additional aspect of the disclosed solution, the combustible gas may be produced with a gasifier (4).

Disclosed herein are a fluid sand falling type circulating fluidized bed boiler with a plurality of risers for preventing erosion and corrosion of water tubes and increasing combustion efficiency, and a method of operating the same. The fluid sand falling type circulating fluidized bed boiler with a plurality of risers includes a boiler section into which fuel and oxidizer are injected, a riser section connected to the boiler section so that the fuel and fluid sand supplied from the boiler section are introduced from the bottom of the riser section and flow up, and a relay section provided on the boiler section to supply the fluid sand having passed through the riser section to the boiler section, wherein the fuel is injected from the top of the boiler section and burned while flowing down therein.

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.

A water-cooled column (4) used in a circulating fluidized bed boiler furnace is disclosed, wherein the water-cooled column is formed by connecting membrane water-cooled walls (41). The water-cooled column (4) includes a lower section (A), an upper section and a transition section. The lower section (A) is a single column and is provided with inner secondary air ports (400) on a side wall thereof. The upper section includes a plurality of sub-columns (B, C). The membrane water-cooled walls at the lower section (A) extend to the upper section through the transition section. Each of the sub-columns (B, C) is formed by connecting extension portions extending upward from respective membrane water-cooled walls (41) in the membrane water-cooled walls (41), which are connected to form the lower section (A), and the plurality of sub-columns (B, C) are separated from each other.

Material handling systems for fluids are disclosed herein. The fluid may be a liquid, solution, slurry, or emulsion. The systems receive as inputs the fluid, steam, and water. These feed into a surge tank where additives can be introduced. The steam and water are used to control some physical properties and enable the distribution of the fluid as desired. In particular embodiments, the system is useful for handling materials to be sent to a dual-phase fuel feeder for combustion in a fluidized-bed boiler, the energy being used to generate electricity or in various production processes.