摘要:
A method of operating a burner includes providing supplying a combustible mixture containing a ratio of fuel and air that is incapable of maintaining a stable flame to a combustion chamber. The combustible mixture is ignited by an igniter, and presence of a flame is sensed. The igniter is maintained active to sustain combustion of the combustible mixture within the combustion chamber so that a space exterior to the combustion chamber is heated to a temperature at or above an auto-ignition temperature of the combustible mixture. The temperature of the space exterior is monitored and the combustible mixture is provided at a second flow rate, which is higher than the first flow rate, to extinguish the flame in the combustion chamber such that combustion occurs in the space exterior to the combustion chamber. When combustion occurs in the space exterior to the combustion chamber, the igniter is deactivated.
摘要:
Included is a method of starting up a direct heating device having a fuel introduction zone, a combustion zone and a process zone that is in heat exchange relationship with said combustion zone. Prior to the introduction of a fuel fluid into said combustion zone, an oxidant fluid, having a high temperature, is passed through the combustion zone for a warm-up time period sufficient to raise the temperature of the direct heating device to a desired temperature. Steam or a process fluid is passed through the process zone followed by the introduction of a fuel fluid into the fuel introduction zone. After the device has been heated up a process fluid is introduced through the process zone. Thereafter, the introduction of steam through the process zone may be stopped.
摘要:
The invention relates to a radiant device with a burner of the nullglove fingernull type, comprising an exchanger (3) for heating air (T1) by the burned gases (T2), a furnace tube (6) drilled with air-intake orifices (60) and terminated by a nozzle (61) disposed facing a recirculation tube (4), and a central gas-injection tube (7). According to the invention, the central injection tube (7) is fed with gaseous fluids in proportions that can be regulated by means of one or to valves (710, 720), via two conduits (71, 72), the first (71) of which transports at least gas and the second (72) of which transports at least air, and the central injection tube (7) ends at a burner (8), which is disposed in the furnace tube (6) and which discharges at the level of the nozzle (61), this arrangement making it possible to adapt existing devices very easily for the purpose of reduced production of nitrogen oxides.
摘要:
A process heater is provided utilizing flameless combustion, the process heater having: an oxidation reaction chamber, the oxidation reaction chamber having an inlet for oxidant, an outlet for combustion products, and a flow path between the inlet and the outlet; a fuel conduit capable of transporting a fuel mixture to a plurality of fuel nozzles within the oxidation reaction chamber, each nozzle providing communication from within the fuel conduit to the oxidation chamber, with each nozzle along the flowpath between the inlet and the outlet; a preheater in communication with the oxidation chamber inlet, the preheater capable of increasing the temperature of the oxidant to a temperature resulting in the combined oxidant and fuel from the fuel nozzle closest to the oxidation chamber inlet being greater than the autoignition temperature of the combined oxidant and fuel from the fuel nozzle closest to the oxidation chamber inlet; and a process chamber in a heat exchange relationship to the oxidation reaction chamber wherein the heat transferred from the oxidation section does not causes the temperature of the mixture within the oxidation reaction chamber in the vicinity of each fuel nozzle to decrease below the auto ignition temperature of the combined mixture in the oxidation chamber in the vicinity of that fuel nozzle.
摘要:
A method of heating matter comprises supplying a gaseous mixture, which is reactable to produce heat, at a temperature above that at which spontaneous ignition occurs to a heating zone such that the gaseous mixture reacts to provide a heated fluid flow in said heating zone, and supplying matter to be heated to said heating zone.
摘要:
A power plant designed to burn fuel in a bed of fluidizable particulate material contained in a combustion chamber includes a tubular discharge device for bed material or dust separated from combustion gases leaving the combustion chamber. The tubular discharge device is designed as a cooler which is cooled by combustion air flowing into the combustion chamber and is utilized for pre-heating the plant upon start-up from a cold state. At least a part of the tubular discharge device, is electrically insulated from parts located upstream and downstream and from supporting structural members and forms an electrical heating unit. Upon start-up, this unit is connected to a current source for heating the air fed to the combustion chamber and downstream parts of the plant.
摘要:
The invention relates to a method of igniting, upon start-up, a combustion chamber (8) in a power plant with combustion of fuel in a fluidized bed (14). The air flow through the nozzles (13) of the combustion chamber bottom (12) for fluidization of the bed (14) and for combustion of the fuel can be reduced upon start-up; bed material, which is heated to the ignition temperature of a start-up fuel, is transferred from a storage container (40) to the combustion chamber (8), and fuel is supplied to the bed (14). In those cases where the air flow has been reduced during the transfer of the bed material, it is increased again when the fuel is supplied. The invention also relates to a power plant having means for temporarily bypassing the nozzles (13) of the combustion chamber bottom (12) while transferring hot bed material from a storage container (40) to the combustion chamber (8), and a fuel system (30-38) for the supply of fuel to the combustion chamber (8). In a plant with a combustion chamber (8) enclosed in a pressure vessel (10), a connection with a valve (55) for by-passing the air flow may be provided between the space (11) in the pressure vessel and the freeboard (18) of the combustion chamber (8) for reducing the air flow through the bed. Further, control means (38, 80) are provided for carrying out the necessary operations of valves, and the like, during the start-up operation.
摘要:
At start-up, a bed of pellets derived from pulp mill residual liquor is fluidized by feeding preheated air to the bed to initially raise the temperature of the bed to a temperature at which a particulate ligno-cellulosic auxiliary solid fuel may be completely consumed (800.degree.-850.degree. F.) and less than the yield temperature of the heat exchanger, feeding the auxiliary fuel to the fluidized bed, so as to burn the auxiliary fuel within the bed, feeding coolant to the heat exchanger to protect the heat exchanger from thermally induced damage, coordinating the rate of feeding of coolant with the rate of injection of the solid fuel to further increase the temperature of the bed to at least a temperature at which concentrated residual liquor from said mill will be burned while maintaining the temperature of the heat exchange equipment below the yield temperature for the material from which the heat exchanger is constructed and without build up of carbon in the bed, injecting concentrated residual liquor fuel from said pulp mill to the bed thereby to burn said residual liquor in the bed, continuing to inject at least one of said fuels, coordinating the rate of fuel injection to operate the bed at operating temperature while simultaneously maintaining a rate of addition of coolant to the heat exchanger to insure the temperature of the metal of the heat exchanger does not exceed the yield temperature.
摘要:
A fluidized bed boiler is started up by directing into the static bed of inert and carbonaceous granules a downwardly angled burner so that the hot gases cause spouting. Air is introduced into the bed at a rate insufficient to fluidize the entire bed. Three regions are now formed in the bed, a region of lowest gas resistance, a fluidized region and a static region with a mobile region at the interface of the fluidized and static regions. Particles are transferred by the spouting action to form a conical heap with the carbonaceous granules concentrated at the top. The hot burner gases ignite the carbonaceous matter on the top of the bed which becomes distributed in the bed by the spouting action and bed movement. Thereafter the rate of air introduction is increased to fluidize the entire bed, the spouter/burner is shut off, and the entire fluidized bed is ignited.