A pressurized cavity is provided around at least a portion or all of a regenerator, within which gas such as flue gas is maintained at a pressure in excess of the pressure within the regenerator, to protect against leakage of gas through the walls of the regenerator.

A pressurized cavity is provided around at least a portion or all of a regenerator, within which gas such as flue gas is maintained at a pressure in excess of the pressure within the regenerator, to protect against leakage of gas through the walls of the regenerator.

A method heats a furnace process chamber with the combustion of fuel gas. The method heats the process chamber in a preheat mode when the temperature of the process chamber is below the autoignition temperature of the fuel gas. The preheat mode forms preheated combustion air by directing the combustion air through a regenerative bed. A stream of the preheated combustion air is directed into the process chamber in a condition unmixed with fuel gas. The preheat mode also forms a fuel rich mixture of the fuel gas and unheated combustion air. The fuel rich mixture is directed into the process chamber adjacent to the stream of preheated combustion air.

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.

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.

A method for burning primary fuel (F1), wherein the primary fuel (F1) comprises at least a first compound containing nitrogen and a second compound comprising sulfur. The method comprises producing primary combustion gas (G1) having a temperature of at least 450° C. and comprising oxygen; feeding the primary fuel (F1) and the primary combustion gas (G1) to a primary process zone (Z1) of a furnace (200); feeding tertiary combustion gas (G3) to a secondary process zone (Z2) of the furnace (200); letting the primary fuel (F1), the primary combustion gas (G1), and/or their reaction products to move from the primary process zone (Z1) via the secondary process zone (Z2) to a tertiary process zone (Z3) of the furnace (200); and feeding quaternary combustion gas (G4) comprising oxygen to the tertiary process zone (Z3) of the furnace (200). An embodiment comprises collecting the primary fuel (F1) from a pulp process. A corresponding system.

A method for burning primary fuel (F1), wherein the primary fuel (F1) comprises at least a first compound containing nitrogen and a second compound comprising sulfur. The method comprises producing primary combustion gas (G1) having a temperature of at least 450° C. and comprising oxygen; feeding the primary fuel (F1) and the primary combustion gas (G1) to a primary process zone (Z1) of a furnace (200); feeding tertiary combustion gas (G3) to a secondary process zone (Z2) of the furnace (200); letting the primary fuel (F1), the primary combustion gas (G1), and/or their reaction products to move from the primary process zone (Z1) via the secondary process zone (Z2) to a tertiary process zone (Z3) of the furnace (200); and feeding quaternary combustion gas (G4) comprising oxygen to the tertiary process zone (Z3) of the furnace (200). An embodiment comprises collecting the primary fuel (F1) from a pulp process. A corresponding system.

To preheat combustion air with gasification furnace flue gas, combustion air is flowed towards an inlet of a gasification furnace. The combustion air is heated using flue gas emitted from the gasification furnace. The flue gas is generated within the gasification furnace responsive to a gasification process. The heated combustion air is flowed into the inlet of the gasification furnace. The gasification process is implemented within the gasification furnace using the heated combustion air

A method and apparatus for heating a furnace using a burner system having first and second burner assemblies, each including a burner and a regenerative media bed, the method including operating the first burner assembly in a firing mode and the second burner assembly in a regeneration mode, switching the first burner assembly from the firing mode to the regeneration mode and the second burner assembly from the regeneration mode to the firing mode, and operating the second burner assembly in the firing mode and the first burner assembly in the regeneration mode. The burner assembly in the firing mode may be fired in either a first operating mode where the burner is supplied with preheated low calorific fuel and the burner is supplied with oxidizing gas or a second operating mode where the burner is supplied with preheated oxidizing gas and the burner is supplied with high calorific fuel.

A method and apparatus for heating a furnace using a burner system having first and second burner assemblies, each including a burner and a regenerative media bed, the method including operating the first burner assembly in a firing mode and the second burner assembly in a regeneration mode, switching the first burner assembly from the firing mode to the regeneration mode and the second burner assembly from the regeneration mode to the firing mode, and operating the second burner assembly in the firing mode and the first burner assembly in the regeneration mode. The burner assembly in the firing mode may be fired in either a first operating mode where the burner is supplied with preheated low calorific fuel and the burner is supplied with oxidizing gas or a second operating mode where the burner is supplied with preheated oxidizing gas and the burner is supplied with high calorific fuel.