Described herein are two-stage catalytic heating systems and methods of operating thereof. A system comprises a first-stage catalytic reactor and a second-stage catalytic reactor, configured to operate in sequence and at different operating conditions, For example, the first-stage catalytic reactor is supplied with fuel and oxidant at fuel-rich conditions. The first-stage catalytic reactor generates syngas. The syngas is flown into the second-stage catalytic reactor together with some additional oxidant. The second-stage catalytic reactor operates at fuel-lean conditions and generates exhaust. Splitting the overall fuel oxidation process between the two catalytic reactors allows operating these reactors away from the stoichiometric fuel-oxidant ratio and avoiding excessive temperatures in these reactors. As a result, fewer pollutants are generated during the operation of two-stage catalytic heating systems. For example, the temperatures are maintained below 1.000° C. at all oxidation stages.

Provided is a water heater including a burner that receives a supply of combustion air from a fan, a heat exchanger having a heat transfer tube, and a combustion chamber case in which a combustion chamber of the burner is formed in the interior thereof and which is to be capable of guiding combustion gas generated by the burner to the heat exchanger. The water heater further includes a unit case that surrounds the combustion chamber case, and a region on the outside of the combustion chamber case within the unit case serves as an air pressure chamber having a higher pressure than the combustion chamber. Thus, combustion gas leakage to the outside can be prevented or suppressed appropriately by means of a simple configuration.

A double swirl burner including an annular air nozzle, an annular fuel nozzle coaxially disposed within the annular air nozzle, and a central air nozzle coaxially disposed within the annular fuel nozzle. An annular air nozzle may include at least one first inlet port on a peripheral wall of the annular air nozzle, where the first inlet port may be configured to allow for tangentially injecting a first air stream into the annular air nozzle. A first air stream may be tangent to a circular cross-section of the exemplary annular air nozzle, and a first axial inlet that may be configured to allow for axially injecting a second air stream into the annular air nozzle along a centerline of the annular air nozzle.

A burner assembly having a blower housing, a blower to supply air to the burner assembly, a blast tube having a longitudinal axis, a fuel source to supply fuel to the burner assembly, a center tube that is substantially parallel to the longitudinal axis and conveys air and fuel to a center tube burner end opening, a plurality of premix tubes, each of which is substantially parallel to the longitudinal axis and conveys air and fuel to a premix tube burner end opening, a diffuser that is disposed in the center tube near the center tube burner end opening, a nozzle that is disposed in the center tube substantially perpendicular to the diffuser. The center tube air and fuel mixture is fuel rich and the premix tubes air and fuel mixture is fuel lean. A method for burning the center tube air and fuel mixture and the premix tubes mixtures.

A process and plant for preheating a metal charge fed in continuous to an electric melting furnace through a preheating tunnel provided with side walls, a vault and a horizontal conveyor, wherein the metal charge is enveloped in countercurrent by fumes or exhaust gases exiting from the electric melting furnace, includes causing an air intake from the surrounding environment through openings along the preheating tunnel to complete the combustion of the fumes or exhaust gases. The intake is regulated by acting on suction fans and/or on the openings, based on measurements by temperature sensors and/or the composition of the outgoing gases in or downstream of the terminal part of the tunnel. The metal charge is enveloped by jets of gas ejected through a plurality of nozzles arranged non-uniformly longitudinally on the vault of the tunnel, with a greater concentration on the top of the vault of the tunnel.

A swirl pintle coal slurry injector including a main body including at least one gas inlet; a pintle coupled to the main body, wherein the pintle comprises at least one coal slurry inlet and at least one slurry outlet, wherein the pintle defines a pintle axis; and a swirler coupled to the main body, wherein the swirler imparts to a gas from the at least one gas inlet of the main body a circular motion around the pintle axis, wherein the swirler surrounds the pintle axis and comprises a swirler number of approximately 1.2. The pintle can include a plurality of orifices of approximately 5 mm diameter.

A gas turbine engine comprising a variable geometry combustor having pilot fuel injectors and main fuel injectors; a fuel metering system configured to control fuel flow to the pilot fuel injectors and the main fuel injectors; a variable geometry airflow arrangement for the variable geometry combustor, which is configured to vary the airflow through the pilot fuel injectors and/or the main fuel injectors; a control system configured to control the variable geometry airflow arrangement in dependence upon airflow delivered to the combustor, the fuel flow to the pilot fuel injectors and the main fuel injectors, and a target index of soot emissions, thereby controlling airflow through the pilot fuel injectors and/or the main fuel injectors and hence the quantity of soot produced by combustion.

Nozzles for delivering air into a combustion system of a boiler utilizing an interchangeable divided nozzle barrel and converging section along with a variable vane. The vane be rotated to different divisions in the nozzle to change the size of the flow area and subsequently the flow velocity of the air into the combustion system to optimize performance and adjust for changes in load and fuel.

A burner and methods of using the burner. The burner utilizes bypass conduits to separate the combustion air that is passed to the primary combustion zone into two or more portions. The two portions are injected into the primary combustion zone at different points so as to reduce the flame temperature. A NOx reducing medium may be mixed with the combustion air in the bypass conduit. The NOx reducing medium may be flue gases from a combustion chamber having the primary combustion zone.

A system for use with a fired vessel of production/separators or dehydration equipment that includes a metal box, a main burner, a pilot burner, and a flame arrestor. The main burner and the pilot burner are within the metal box and the first flame arrestor is connected to the metal box.