A plugging resistant, highly stable free-jet burner and method which provide Ultra-Low NO.sub.x emissions using (a) large free-jet ejection ports, (b) a wide tip-to-tip spacing, and (c) auxiliary stabilization tips in the throat of the burner which are highly resistant to plugging and also produce very low levels of NO.sub.x emissions.

A combustion system such as a furnace or boiler includes a perforated reaction holder configured to hold a combustion reaction that produces very low oxides of nitrogen (NOx).

Embodiments disclosed herein are directed to methods of upgrading a conventional combustion system into an upgraded combustion system that includes a perforated flame holder. For example, the perforated flame holder may improve operational efficiency of the combustion system and/or reduce pollutants such as NO.sub.x output by the upgraded combustion system.

A gas turbine engine and a combustor are described herein. The combustor includes a fuel vaporizer coupled to a combustor wall, which extends into a combustion chamber. A fuel injector having a nozzle extends within a portion of the fuel vaporizer. A dome swirler is coupled to an upstream dome portion of the combustor wall. The swirler surrounds a heat shield, which may have a concaved body. The outlet end of the fuel vaporizer is disposed over the heat shield, which may be over the central zone of the heat shield, to face the heat shield. The fuel vaporizer may be coupled to the combustor wall and disposed outside the swirler. Fuel and air mixture exits the vaporizer and impinges against the heat shield and is then combined with the swirler air to become part of the primary zone recirculation.

Horizontal immersion tube boilers include a plurality of burner nozzles positioned in substantial alignment with a respective plurality of boiler tubes. Fuel-air mixture directed through the burner nozzles are ignited by a pilot flame system positioned proximate to the burner nozzles within a combustion chamber. The burner nozzles and pilot flame system receive air from a secondary air manifold having inlets that provide secondary air into the combustion chamber. The flames extending from the burner nozzles are directed into the respective boiler tubes, which exchange heat from the flame into water within a boiler shell. The secondary air inlets direct air around the burner nozzles and toward the boiler tubes, creating an air blanket around each burner nozzle for reducing turbulence and guide the flames into their respective boiler tubes. An improved flame arrestor within the nozzle prevents flame back-flow when modulating to lower firing rates.

The embodiments of the present application disclose a gas premix burner and a gas water heater. The gas premix burner has a combustion direction, the gas premix burner can be matched and connected with a premix chamber that is disposed upstream the combustion direction of the gas premix burner, gas and air can be burned by the gas premix burner after mixed in the premix chamber; the gas premix burner comprising: a burner substrate, a main combustion hole provided on the burner substrate; an auxiliary combustion hole disposed downstream the main combustion hole along the combustion direction on the burner substrate; an auxiliary flame of the auxiliary combustion hole intersects a main flame of the main combustion hole. The present application provides the main combustion hole upstream the auxiliary combustion hole along the combustion direction, since the main flame is usually larger in scale than the auxiliary flame, by providing the main flame upstream the auxiliary flame, it will be easier for the auxiliary flame and the main flame to intersect each other, and then the effect of stabilizing the flame is realized by opposed flames formed by the auxiliary flame and the main flame.

A burner includes a first tube portion formed with an ejection port; a second tube portion that extends in the first tube portion toward the ejection port and to which gaseous mixture flows in from a side opposite to the ejection port; a third tube portion arranged in the first tube portion and including an open end positioned on the ejection port side; a closing portion that closes the open end; a coupling wall portion that closes a gap between the first tube portion and the second tube portion; a partition wall that is coupled to the first tube portion and the third tube portion, the partition wall being formed with a communication path; and an igniting portion that is arranged on the ejection port side with respect to the partition wall.

A combustion system includes a fuel and oxidant source that outputs fuel and oxidant, a first perforated flame holder, and a second perforated flame holder separated from the first perforated flame holder by a gap. The first and second perforated flame holders sustain a combustion reaction of the fuel and oxidant within the first and second perforated flame holders.

A plugging resistant, highly stable free-jet burner and method which provide Ultra-Low NO.sub.x emissions using (a) large free-jet ejection ports, (b) a wide tip-to-tip spacing, and (c) auxiliary stabilization tips in the throat of the burner which are highly resistant to plugging and also produce very low levels of NO.sub.x emissions.

Horizontal immersion tube boilers include a plurality of burner nozzles positioned in substantial alignment with a respective plurality of boiler tubes. Fuel-air mixture directed through the burner nozzles are ignited by a pilot flame system positioned proximate to the burner nozzles within a combustion chamber. The burner nozzles and pilot flame system receive air from a secondary air manifold having inlets that provide secondary air into the combustion chamber. The flames extending from the burner nozzles are directed into the respective boiler tubes, which exchange heat from the flame into water within a boiler shell. The secondary air inlets direct air around the burner nozzles and toward the boiler tubes, creating an air blanket around each burner nozzle for reducing turbulence and guide the flames into their respective boiler tubes. An improved flame arrestor within the nozzle prevents flame back-flow when modulating to lower firing rates.