A biomass-mixed, pulverized coal-fired burner is provided, capable of burning biomass fuel as auxiliary fuel in large quantities and burning only pulverized coal when the biomass fuel is not sufficiently available. The biomass-mixed, pulverized coal-fired burner includes a biomass fuel jet nozzle that extends axially along the biomass-mixed, pulverized coal-fired burner, a fuel jet nozzle that is open midway in the biomass fuel jet nozzle, a secondary air nozzle that surrounds the fuel jet nozzle, and a tertiary air nozzle that surrounds the secondary air nozzle. A pulverized coal component in a fuel stream as a mixture of the pulverized coal fuel stream and the biomass fuel stream is distributed with a higher concentration on an outer circumferential wall side and a biomass fuel component in the fuel stream is distributed inside of the pulverized coal fuel component.

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.

Disclosed is a staged-air burner device capable of high energy efficiency, high flame stability, combusting multiple readily switchable fuels ranging from pure hydrogen, to any hydrogen/methane mixture, to pure methane, and generating a low level of NOx. The burner device can include: a primary air chamber receiving a primary air and a flue gas; a burner tube capable of receiving a fuel jet and drawing in the air-flue gas mixture from the primary air chamber; a burner tip discharging the fuel-air-flue gas mixture formed in the burner tube to a first combustion zone and a second combustion zone via center orifices and side orifices on the burner tip, respectively; and a staged air chamber receiving staged air and discharging it via staged air ports into a third combustion zone. Combustion of the fuel occurs in at least one of the first, second, and third combustion zones.

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.

The burner preferably exclusively burns substantially explosible solid fuels and preferably has instant ON-OFF thermostat control, wastes no energy preheating the enclosure or external air supply, achieves stable combustion the moment the powder-air mix is ignited in our burner, is used in the upward vertical mode except for oil burner retrofits, burns a solid fuel in a single-phase regime as if it were a vaporized liquid or gas, is designed to complete combustion within the burner housing itself rather than in a large, high temperature furnace enclosure which it feeds, has an ultra-short residence time requirement, is a recycle consuming burner with self-contained management of initially unburned particles, is much smaller, simpler and lower cost, has a wider dynamic range/turndown ratio, is more efficient in combustion completeness and thermal efficiency, and operates with air-fuel mix approximately at the flame speed.

In a low NOx boiler of the present invention, a high-temperature reductive combustion zone is provided to an upper portion of a rectangular combustion chamber, and a second-step combustion zone is provided to a middle stage of the combustion chamber. A wall provided below the second-step combustion zone is tapered to narrow the combustion chamber, with a taper angle of approximately 35 or so, relative to a vertical line. An ash discharge port is provided to a furnace bottom portion, and a gas outlet port communicated with a rear pass is provided to a lower side face of the second-step combustion zone. This rear pass is connected with a further post-treatment step, via a super-heater tube and an economizer.

A burner is disclosed for generating flame and heat. The burner includes a first stage, a second stage downstream of the first stage, a third stage downstream of the first and second stages, and a fourth stage downstream of the first, second, and third stages. The first stage comprises a first innermost air chamber and a first mixing chamber for air and fuel, wherein the first stage includes separate conduits for air and fuel, and wherein the air and fuel begin to mix in the first mixing chamber during use to form an air/fuel mixture. The second stage comprises a second mixing chamber which comprises a deflection plate to force the air/fuel mixture outward from the centerline. The third stage comprises a combustion zone. The combustion zone includes a swirl generator. The swirl generator has an inner diameter greater than an outer diameter of the deflection plate. The swirl generator produces a swirl, whirl, vortex, or the like in the flame during operation.

A rich-lean burner has on an upper end portion thereof: a lean flame port longitudinally extended to eject a lean fuel-air mixture which is leaner in fuel concentration than a theoretical fuel-air ratio; a blind clearance located on each lateral side of the lean flame port, the blind clearance being free from ejection of a fuel-air mixture; and a rich flame port located on lateral outside of each of the blind clearances to eject a rich fuel-air mixture which is richer in fuel concentration than the theoretical fuel-air ratio. The rich-lean burner further has a lean-flame deforming device to deform a lean flame formed by combustion of the lean fuel-air mixture ejected from the lean flame port such that the shape of one lateral side of the lean flame becomes asymmetrical with the shape of laterally opposite side of the lean flame.

A combustion burner 1 includes a fuel nozzle 2 that injects fuel gas prepared by mixing solid fuel and primary air, secondary air nozzles 3, 4 that inject secondary air from the outer periphery of the fuel nozzle 2, and a flame holder 5 that is arranged in an opening of the fuel nozzle 2. In the combustion burner 1, the flame holder 5 has a splitting shape that widens in the flow direction of the fuel gas. When seen in cross section along a direction in which the flame holder 5 widens, the cross section passing through the central axis of the fuel nozzle 2, a maximum distance h from the central axis of the fuel nozzle 2 to the widened end of the flame holder 5 and an inside diameter r of the opening 21 of the fuel nozzle 2 satisfy h/(r/2)<0.6.

The burner device for high-temperature air combustion according to the present invention is equipped with a thermal insulation portion (5) that is provided facing a furnace (1) and has a throat (6); a burner nozzle (9) that is provided at the axial center of this throat and that injects a pulverized coal mixed flow (38) into the furnace through the throat; a windbox (8) that is provided so as to house this burner nozzle; an air register (16) that is provided at the distal end of the burner nozzle and that injects low-temperature secondary air from the windbox to the throat; a high-temperature air nozzle (23), one end of which opens into the furnace through the heat insulation portion; and a combustion air switching means (16, 24) that switches between injecting low-temperature secondary air to the throat through the air register and injecting high-temperature secondary air to the furnace interior through the high-temperature air nozzle, in which in steady combustion, low-temperature secondary air is injected to the throat through the air register by the combustion air switching means and a pulverized coal mixed flow is injected from the burner nozzle, and in high-temperature air combustion, high-temperature secondary air is injected to the furnace interior through the high-temperature air nozzle by the combustion air switching means and a pulverized coal mixed flow is injected from the burner nozzle.