A circulating fluidized bed (CFB) boiler has one or more bubbling fluidized bed enclosures containing heating surfaces and located within a lower portion of the CFB boiler to provide an in-bed heat exchanger (IBHX). Solids in the bubbling fluidized bed are maintained in a slow bubbling fluidized bed state by separately controlled fluidization gas supplies. The beds feature open bottom distribution grids with hoppers disposed below to collect solids. The enclosure defining the IBHX is supported from structures below the grids and the enclosure can be supported from the hoppers.

The present invention provides a circulating fluidized bed boiler, comprising: furnace side walls; a ceiling; an air distribution plate provided at a bottom of a furnace; and at least one air distribution cone provided on the air distribution plate, wherein each air distribution cone extends upwards from the air distribution plate into an interior of the furnace and has a shape gradually tapered in an extending direction, cone side walls which form the air distribution cone are provided with secondary air ports, the cone side walls are separated from the furnace side walls, and a furnace combustion space is formed and surrounded by the ceiling, the furnace side walls, the air distribution plate, and the cone side walls. The present invention further relates to an air distributor for a circulating fluidized bed boiler, the air distributor being provided on an air distribution plate of the boiler, wherein the air distributor is in a form of an air distribution cone, which extends upwards from the air distribution plate into an interior of a furnace to form a shape gradually tapered in an extending direction, and secondary air ports are formed in air distribution cone side walls forming the air distribution cone. The present invention also relates to an air distributor assembly for a circulating fluidized bed boiler.

A method of heat transfer wherein a flat metal product having a broad face and a temperature upper to 400° C. is put in contact with a fluidized bed of solid particles, the solid particles having a direction of circulation (D), wherein the flat metal product is put in contact with the solid particles so that its broad face is parallel to the direction (D) of circulation of the solid particles and wherein a gas is injected so that the solid particles be in a bubbling regime, the solid particles capturing the heat released by the metal product and transferring the captured heat to a transfer medium. An associated device is also provided.

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.

A fluidized-bed boiler integrating a multifunctional inertia-gravity separator and a plurality of models of boilers. The fluidized-bed boiler is a steam boiler, a hot-water boiler or a phase-transformation boiler. The fluidized-bed boiler includes a hearth, a single horizontal drum, a vertical single drum, vertical and horizontal headers, vertical and horizontal membrane walls, a primary high-temperature inertia-gravity water-cooling separator, a secondary low-temperature inertia-gravity water-cooling separator, a single-stage high-temperature water-cooling inertia-gravity separator, an equalizing, separating and heat storing device, a membrane water-cooling wall shaft, a shell shaft and a dry-wall shaft. The present disclosure provides a circulating fluidized bend boiler with a plurality of models of boilers, which comprehensively improves the boiler performance, drastically realizes the energy conversation, consumption reduction and emission reduction and has advanced process.

A system can quickly cool and de-pressurize a boiler arrangement under non-normal operating conditions such as loss of plant power. A discharge system injects into the furnace a combined stream of steam from a steam discharge system and ambient air, thereby both cooling components of the boiler arrangement and reducing pressure in the steam/water circuit. This reduces or eliminates the additional cost associated with providing extra capacity in a steam drum and/or an independently powered boiler water pump. The system is particularly useful for quickly cooling the U-beams of a circulating fluidized bed boiler during a black plant condition.

A system can quickly cool and de-pressurize a boiler arrangement under non-normal operating conditions such as loss of plant power. A discharge system injects into the furnace a combined stream of steam from a steam discharge system and ambient air, thereby both cooling components of the boiler arrangement and reducing pressure in the steam/water circuit. This reduces or eliminates the additional cost associated with providing extra capacity in a steam drum and/or an independently powered boiler water pump. The system is particularly useful for quickly cooling the U-beams of a circulating fluidized bed boiler during a black plant condition.