A boiler has a shell surrounding a vertical centerline. The shell defines an inner surface having an inner diameter and an inner length extending between an upper upstream end and a lower downstream end. The inner surface defines a hollow interior, the boiler having a pre-combustion zone, a combustion zone downstream from the pre-combustion zone, and a post-combustion zone downstream from the combustion zone. The shell is tapered outward along its length in at least a portion of the combustion zone. An oxidizer inlet is in fluid communication with the pre-combustion zone, and a fuel nozzle introduces fuel into the combustion zone. A tube assembly is mounted in the hollow interior of the shell for transferring heat to fluid flowing through the tube assembly. A flue duct is in fluid communication with the post-combustion zone for transporting flue gases from the hollow interior.

A hydrogen gas burner structure includes a first cylinder tube, a second cylinder tube, a third cylinder tube, and an ignition device. An inside of the first cylinder tube is configured such that hydrogen gas flows. A space between the first cylinder tube and the second cylinder tube is configured such that a first combustion-supporting gas containing oxygen gas flows. A space between the second cylinder tube and the third cylinder tube is configured such that a second combustion-supporting gas containing oxygen gas flows. The ignition device is configured to ignite mixed gas. The tip of the first cylinder tube is located upstream of the tips of the second and third cylinder tubes in a gas flow direction in which the hydrogen gas and the first combustion-supporting gas and the second combustion-supporting gas flow.

Process heaters and associated methods of processing with ultra-low pollutant emissions are provided. The process heaters and methods utilize a heat exchange tube having disposed therein a radiant permeable matrix burner at a first end of the tube. The tube further includes a thermally insulated insert disposed adjacent the radiant burner opposite an oxidant-fuel mixer that feeds the burner. The process heaters and methods act to reduce emissions of CO and NOx.

An oxy-gaseous fuel burner (400, 500) or a solid fuel burner (700) having an annular cavity (404, 504, 704) upstream from and proximate to an outlet plane (416, 516, 716) and a converging (434, 734) or converging-diverging nozzle (537) located upstream from and proximal to the cavity (404, 504, 704). The solid fuel burner (700) also is preferably operated so that the velocity of gas exiting a second annulus (730) is less than the velocity of gas exiting a central conduit (710).

In a combustion apparatus provided with: a combustion box having a connection flange part for connecting a heat exchanger to an upper end of the combustion box; a partition plate disposed inside the combustion box for partitioning space inside the combustion box into a combustion chamber and an air supply chamber which lies under the combustion chamber; and a plurality of laterally arrayed burners which are elongated longitudinally, the internal volume of the combustion box is increased without increasing a height dimension or without enlarging the connection flange part, thereby restraining the occurrence of resonance sounds. A drawn part projecting laterally outward of the combustion box is provided in such a portion of each side-plate part as is above the partition plate, over a predetermined range in the vertical and longitudinal directions. An upper side of the drawn part is preferably positioned below the upper end of the burners, and is preferably parallel with the upper end of the burners.

A boiler performs mixed-fuel combustion of a sulfur-containing fuel and ammonia as a fuel, and includes a furnace having a plurality of wall parts, a burner installed on at least one of the wall parts of the furnace, and an ammonia injection port that is configured to cause the ammonia to be burned as the fuel to flow along an inner wall surface of the wall part where the burner is not installed.

High turndown ratio gaseous fuel burner nozzles and the control thereof are provided. High turndown ratio gaseous fuel burner nozzles include a mechanically adjustable nozzle port, such as in the form of an iris port, for expanded turndown control. A nozzle extension longitudinally extending from the mechanical adjustable nozzle port can be included to assist in shaping the flow of combustible gas from the nozzle port. A laminar flow insert can be housed within the nozzle extension to assist in producing laminar flow of the combustible gas flowing therethrough. A burner nozzle controller in control communication with the mechanically adjustable nozzle port can adjust the size of the nozzle port to selectively maintain exit velocity of the gaseous fuel from the nozzle port for one or more of combustion stability and flame stability.

Regenerative burner for non-symmetrical combustion and a method of firing the burner. The burner includes a burner housing enclosing a burner plenum; a fuel conduit extending longitudinally within the housing and positioned coaxial with a line spaced from a central axis of the burner, with the fuel conduit defining a fuel exit opening; and a baffle positioned at least partially around the fuel conduit and defining an air conduit extending into the housing and defining an air opening on an opposite side of the burner central axis from the fuel exit opening. The baffle also defines a cavity adjacent the fuel exit opening and in communication with the fuel conduit through the fuel exit opening. The sidewall of the cavity converges from a central axis of the fuel conduit to provide further jet penetration into the furnace and achieve greater levels of products of combustion entrainment prior to combustion.

An oxy-gaseous fuel burner (400, 500) or a solid fuel burner (700) having an annular cavity (404, 504, 704) upstream from and proximate to an outlet plane (416, 516, 716) and a converging (434, 734) or converging-diverging nozzle (537) located upstream from and proximal to the cavity (404, 504, 704). The solid fuel burner (700) also is preferably operated so that the velocity of gas exiting a second annulus (730) is less than the velocity of gas exiting a central conduit (710).

A gas burner for burning a gas with a low calorific value. The gas burner may be for burning a synthesis gas issuing from the gasification of biomass.