A comprehensive utilization system for high-temperature gasification and low-nitrogen combustion of biomass comprises a gasifier, a boiler and a burner installed on the boiler. The outlet of the gasifier is connected to a fuel inlet of the burner. The boiler is provided with flue-gas exhaust ports connected to a chimney. Regenerative heat exchangers are provided between the flue-gas exhaust ports and the chimney, preheating air pipes are connected to the regenerative heat exchangers and then to an auxiliary mixing chamber. The auxiliary mixing chamber is provided with a first outlet connected to the inlet of the mixer, and a second outlet connected to the high-temperature air inlet of the gasifier and the second combustion-air inlet of the burner. An outlet of the mixer is connected with the first combustion-air inlet of the burner. The chimney is connected with the flue gas inlet of the gasifier through pipes and fans.

A heat recovery unit for generating a heated fluid by a hot exhaust gas includes a housing having an inlet for introducing hot exhaust gas and an outlet for discharging treated exhaust gas, and arranged in the housing at least one heat exchanger for heat exchange between the hot exhaust gas and a fluid, and an auxiliary combustor for combusting fuel with hot exhaust gas. The auxiliary combustor is provided with a fuel supply, which auxiliary combustor is arranged downstream of the at least one heat exchanger in the housing. An exhaust gas bypass for a part of the hot exhaust gas is provided, having an inlet for exhaust gas, and being positioned upstream of the at least one heat exchanger, and having an outlet in direct fluid communication with the auxiliary combustor.

A boiler is disclosed in which the furnace is divided into a lower furnace and an upper furnace. The lower furnace uses water-cooled membrane walls, while the upper furnace uses steam-cooled membrane walls that act as superheating surfaces. A transition section is present between the lower furnace and the upper furnace. The boiler is a high temperature sub-critical natural circulation boiler which is completely top supported. The lower furnace is supported through the transition section by the upper furnace.

A boiler is disclosed in which the furnace is divided into a lower furnace and an upper furnace. The lower furnace uses water-cooled membrane walls, while the upper furnace uses steam-cooled membrane walls that act as superheating surfaces. A transition section is present between the lower furnace and the upper furnace. The boiler is a high temperature sub-critical natural circulation boiler which is completely top supported. The lower furnace is supported through the transition section by the upper furnace.

A boiler is disclosed in which the furnace is divided into a lower furnace and an upper furnace. The lower furnace uses water-cooled membrane walls, while the upper furnace uses steam-cooled membrane walls that act as superheating surfaces. The upper furnace and the convection pass are also located next to each other, so that they share a common steam-cooled wall. There is no open pass between the furnace and the convection pass.

A boiler is disclosed in which the furnace is divided into a lower furnace and an upper furnace. The lower furnace uses water-cooled membrane walls, while the upper furnace uses steam-cooled membrane walls that act as superheating surfaces. The upper furnace and the convection pass are also located next to each other, so that they share a common steam-cooled wall. There is no open pass between the furnace and the convection pass.

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).

The invention provides a hydrogen boiler based on coal gasification and water decomposition, including a steam boiler which includes an upper furnace and a lower furnace; water and steam in the upper furnace are respectively communicated with water and steam in the lower furnace; and the steam boiler is provided with a casing which has a narrow gap for containing water and a wide wall for heating to generate gas. The steam boiler contains multistage reactors. A coal modification and gasification device is provided at an outer side of the steam boiler and is provided with two chambers. The steam and gasified gas of coal are mixed and enter the reactors for direct burning to promote respective reactions. After several stages of modification and decomposition, the steam and the gasified gas of coal are completely converted to hydrogen.

The invention provides a hydrogen boiler based on coal gasification and water decomposition, including a steam boiler which includes an upper furnace and a lower furnace; water and steam in the upper furnace are respectively communicated with water and steam in the lower furnace; and the steam boiler is provided with a casing which has a narrow gap for containing water and a wide wall for heating to generate gas. The steam boiler contains multistage reactors. A coal modification and gasification device is provided at an outer side of the steam boiler and is provided with two chambers. The steam and gasified gas of coal are mixed and enter the reactors for direct burning to promote respective reactions. After several stages of modification and decomposition, the steam and the gasified gas of coal are completely converted to hydrogen.

An arrangement in a recovery boiler having a furnace for combusting waste liquor and a flue gas duct comprising vertical flue gas channels, at least part of which is provided with heat recovery units for recovering heat from flue gases. The heat recovery units have a width of substantially the width of the flue gas duct, whereby downstream of the furnace the first flue gas channel is provided with a superheater. In addition to the superheater, the first flue gas channel is provided with one of following heat recovery units: an economizer, a boiler bank, or a reheater. The superheater and a second heat recovery unit are located one after the other in horizontal introduction direction of the flue gas, so that in a flue gas channel the flue gas flows in the vertical direction downwards and heats the superheater and the second heat recovery unit simultaneously.