A fire pit includes an engine having at least one wall defining an inner chamber. At least one primary air aperture is defined through the inner chamber wall at a first, lower level, and at least one secondary air aperture is defined through the inner chamber wall at a second, upper level. A fuel grate is supported within the inner chamber at a level between the lower level and the upper level.

A fire pit includes an engine having at least one wall defining an inner chamber. At least one primary air aperture is defined through the inner chamber wall at a first, lower level, and at least one secondary air aperture is defined through the inner chamber wall at a second, upper level. A fuel grate is supported within the inner chamber at a level between the lower level and the upper level.

The present invention relates to an over fire air arrangement for a furnace (1), the furnace (1) having opposing first wall (4) and second wall (6) and opposing first side wall (5) and second side wall (7) between the first and second walls (4, 6) for forming a furnace enclosure (2). The over fire air arrangement comprising at least one first over fire air port (20) provided to the first wall (4) for supplying a first over fire air flow (40) into the furnace (1) and at least one first additional over fire air port (50) provided to at least one of the first and second side walls (5, 7) in the vicinity of the first wall (4), the at least one first additional over fire air port (50) being arranged to supplying a first additional over fire air flow (60) into the furnace (1) transversely to the first over fire air flow (40).

A combustion/pyrolization system comprising a combustion/pyrolization chamber supported by the base frame, and a perforated grate forms a bottom surface of the combustion/pyrolization chamber and facilitates passage of char and boichar therethrough. The combustion/pyrolization chamber is open along at a top and an air manifold supplies a first source of combustion air across the top of the combustion/pyrolization chamber to form an air curtain. A char collection/transfer chamber is located below the perforated grate for collecting at least the char and boichar that passes therethrough, and a conveying mechanism transfers the char and boichar out of the combustion/pyrolization system for collection and use. An air plenum chamber cools the char collection/transfer chamber such that the supplied secondary air becomes heated, and the heated secondary air flows into the char collection/transfer chamber and through the perforated grate into the combustion/pyrolization chamber to provide secondary combustion air.

The invention pertains to a burner for solid fuel, said burner comprising: A stoker (41) having a fuel outlet (29) within said burner, and an exhaust (31), a grate (27) positioned below said fuel outlet (29) and between said fuel outlet (29) and said exhaust (31), a first blower (92) connected to a space below said grate (27), and a second blower (68) connected to a plurality of injectors (61A, 62A) provided around said fuel outlet (29) above said grate (27) and directed towards said exhaust (31), said injectors (61A, 62A) being parallel and unidirectionally directed over said grate (27), and wherein the injectors (61A, 62A) are provided along the periphery of said burner, said injectors (61A, 62A) being configured for injecting secondary air at a speed of 40-80 m/s, thereby ensuring unidirectional parallel flows of secondary air over said grate (27).

The invention pertains to a burner for solid fuel, said burner comprising: A stoker (41) having a fuel outlet (29) within said burner, and an exhaust (31), a grate (27) positioned below said fuel outlet (29) and between said fuel outlet (29) and said exhaust (31), a first blower (92) connected to a space below said grate (27), and a second blower (68) connected to a plurality of injectors (61A, 62A) provided around said fuel outlet (29) above said grate (27) and directed towards said exhaust (31), said injectors (61A, 62A) being parallel and unidirectionally directed over said grate (27), and wherein the injectors (61A, 62A) are provided along the periphery of said burner, said injectors (61A, 62A) being configured for injecting secondary air at a speed of 40-80 m/s, thereby ensuring unidirectional parallel flows of secondary air over said grate (27).

Nozzles for delivering air into a combustion system of a boiler including an interchangeable nozzle barrel. Nozzle barrels can be easily replaced for maintenance or to change the size and flow velocity of the nozzles to optimize combustion performance. Nozzles may include converging sections with an arc, double arc's, bell shaped, or hyperbolic curves around the entire perimeter of the nozzle and optimized for delivery of air into the combustion system from ducting or from within a plenum.

A chemical recovery boilers is described in which the primary air system is reconfigured to provide aggressive charbed control and improved combustion in the lower furnace. The fewest number of primary air ports are used on two opposing walls to generate powerful air jets that penetrate across the boiler providing physical and thermal stability to the charbed while increasing the heat release and combustion stability in the lower furnace, increasing reduction efficiency, and lowering carryover and emissions. Various embodiments are described including operating strategies and multi-level black liquor injection.

Heat and power engineering, specifically being heating devices includes a pyrolysis boiler, in which, wood is subjected to high-temperature gasification and pyrolysis with subsequent burning off of pyrolysis gases. A stable and controllable gasification of wood with a natural high moisture content is achieved, and at the same time, a highly efficient transfer of combustion heat to a liquid heat-transfer agent is obtained. A gasification chamber is positioned between two compartments of a pyrolysis gas combustion chamber of the pyrolysis boiler, while the external wall of the combustion chamber is used as a heat-transfer surface, and at the same time, neither the fuel bunker nor the gasification chamber are in contact with water.

In accordance with the flow distribution of combustion gas including an unburned portion, an after-air port (AAP) arranged downstream of the two-stage combustion burner can effectively reduce the unburned portion by dividing as appropriate so as to avoid interaction, and by mixing together, two types of after-air having functions of linearity and spreading. As the configuration of this AAP, a primary nozzle for supplying primary after-air and having a vertical height greater than the horizontal width is provided in the center in the opening of the AAP, a secondary nozzle for supplying secondary after-air is provided in the opening outside of the primary nozzle, and one or more secondary after-air guide vanes having a fixed or variable tilt angle relative to the after-air port center axis are provided at the outlet of the said secondary nozzle to deflect and supply the secondary after-air horizontally to the left or right.