A scroll heating device includes a base, a reaction region, and a first and a second channel. The reaction region is at the center of the base. The two channels are located on the base and extend spirally from the reaction region toward the periphery of the base. The width of each channel is gradually reduced as the channel extends from adjacent to the center of the base toward the periphery of the base. The first channel allows a gas that flows into the first channel through the periphery of the base toward the center of the base to flow toward the reaction region at a progressively slower rate, enter the reaction region slowly through the gradually widening first channel, and therefore stay in the reaction region for longer. The combusted exhaust enters the second channel from adjacent to the center of the base and exits through the periphery of the base.

A scroll heating device includes a base, a reaction region, and a first and a second channel. The reaction region is at the center of the base. The two channels are located on the base and extend spirally from the reaction region toward the periphery of the base. The width of each channel is gradually reduced as the channel extends from adjacent to the center of the base toward the periphery of the base. The first channel allows a gas that flows into the first channel through the periphery of the base toward the center of the base to flow toward the reaction region at a progressively slower rate, enter the reaction region slowly through the gradually widening first channel, and therefore stay in the reaction region for longer. The combusted exhaust enters the second channel from adjacent to the center of the base and exits through the periphery of the base.

Embodiments of the present invention include high-temperature staged recirculating burners and radiant tube burner assemblies that provide high efficiency, low NOx and CO emissions, and uniform temperature characteristics. One such staged recirculating burner includes a combustion tube having inside and outside helical fins forming opposing spiral pathways for combustion gases and products of combustion, a combustion nozzle coupled to the combustion tube, a gas tube running axially into the combustion tube, and a staging gas nozzle coupled to the gas tube, where the staging gas nozzle includes radial exit holes into the combustion tube and an axial gas staging tube extending into the combustion nozzle to stage combustion.

According to an embodiment, a fired heater includes a fuel and combustion air source configured to output fuel and combustion air into a combustion volume, the combustion volume including a combustion volume wall defining a lateral extent separate from an exterior volume. According to an embodiment, the fired heater includes a boiler heater and the combustion volume wall comprises a combustion pipe defining a lateral extent of the combustion volume, the combustion pipe being disposed to separate the combustion volume from a water and steam volume. The fired heater includes a mixing tube aligned to receive the fuel and combustion air from the fuel and combustion air source. The mixing tube may be separated from the combustion volume wall by a separation volume. The fired heater includes a bluff body flame holder aligned to receive a fuel and combustion air mixture from an outlet end of the mixing tube. The bluff body flame holder may be configured to hold a combustion reaction for heating a combustion volume wall. The combustion volume wall may include a combustion pipe. The combustion pipe may be configured to heat the water in the water and steam volume.

A cylindrical burner apparatus and method which produce low NO.sub.x emissions and low noise levels without being dependent upon a blower, or natural draft, for providing air flow. A flow of combustion air is induced into a cylindrical burner lube by discharging a gas fuel from a plurality of discharge ports located inside the rearward end of the tube. At least some of the discharge ports are oriented to direct jets of the gas fuel toward flame stabilization structures positioned downstream of the discharge ports.

A system and method uses a combustor and gasifier to burn a primary dirty fuel, such as waste materials or high-polluting fossil fuels, and a secondary low-polluting fuel, such as biomass fuels, for co-generation of electricity while reducing harmful emissions. The primary fuel is burned at least partially through the use of an improved burner tube. Dirty exhaust from a combustor is scrubbed by a gasifier by reforming the combustors exhaust gases into a clean-burning producer gas (syn-gas). The secondary fuel and oxygen are added to the dirty exhaust in the gaslifier to create gas, char and ash. The gas powers an engine or turbine that turns a generator, or a boiler, Stirling engine, or Organic Rankine Cycle power plant, and releases a cleaner exhaust.

A supercritical CO.sub.2 boiler capable of realizing uniform combustion, corrosion resistance and coking resistance, and a boiler system are provided. The supercritical CO.sub.2 boiler includes a main combustion chamber, an upper furnace, a furnace arch and a flue, wherein a cross section of the main combustion chamber is circular or oval, or is of an N-sided shape, where N>4; at least four burner groups are disposed on the main combustion chamber, each group of burner nozzles corresponding to each burner group includes a recirculating air nozzle, a primary air nozzle and a secondary air nozzle; lateral recirculating air nozzles symmetrically distributed are respectively disposed at two sides of the primary air nozzle, the recirculating air nozzle and the lateral recirculating air nozzle are configured to feed recirculating flue gas or a mixed gas of the recirculating flue gas and secondary air into the main combustion chamber.

A supercritical CO.sub.2 boiler capable of realizing uniform combustion, corrosion resistance and coking resistance, and a boiler system are provided. The supercritical CO.sub.2 boiler includes a main combustion chamber, an upper furnace, a furnace arch and a flue, wherein a cross section of the main combustion chamber is circular or oval, or is of an N-sided shape, where N>4; at least four burner groups are disposed on the main combustion chamber, each group of burner nozzles corresponding to each burner group includes a recirculating air nozzle, a primary air nozzle and a secondary air nozzle; lateral recirculating air nozzles symmetrically distributed are respectively disposed at two sides of the primary air nozzle, the recirculating air nozzle and the lateral recirculating air nozzle are configured to feed recirculating flue gas or a mixed gas of the recirculating flue gas and secondary air into the main combustion chamber.

A cylindrical burner apparatus and method which produce low NO.sub.x emissions and low noise levels without being dependent upon a blower, or natural draft, for providing air flow or flue gas recirculation. A flow of combustion air is induced into the initial tube pass of the burner by discharging a gas fuel from a plurality of discharge ports located in the initial tube pass. At the same time, a flow of recycled flue gas is induced through a bypass duct between a subsequent tube pass of the burner and the initial tube pass by discharging one or more jets of gas fuel through the bypass duct.

The disclosed technology includes a fluid heating device including a frustoconical combustion chamber and a heat exchanger that can include heating tubes. The combustion chamber can have a first end and a second end that is in fluid communication with the heating tubes. The surface area of the second end of the combustion chamber can be larger than the surface area of the first end of the combustion chamber.