Abstract: A continuous system and method for purging waste gases from dual heat exchange beds associated with a regenerative thermal oxidizer are disclosed. The system includes a purge recovery tank, a stack open to the atmosphere, a stack bypass, a stack valve in the stack, and a stack bypass valve in the stack bypass. The purge recovery tank is in fluid communication with two heat exchange beds, the stack, and the stack bypass. The stack is in fluid communication with the stack bypass and the heat exchange beds. A purge recycle control valve is used to recycle untreated waste gases from the purge recovery tank to the heat exchange beds and into the regenerative thermal oxidizer. A second embodiment wherein the purge recovery tank is positioned between the two heat exchange beds is also disclosed.

Abstract: The present invention is directed to a method which significantly improves the efficiency of reducing nitrogen oxide formation and emission during incineration of a waste gas in an air-staged thermal oxidizer. In accordance with the present invention, a natural gas stream is mixed with combustion air in a burner and the mixture is ignited with the immediate introduction of liquid water. Thus, the resulting mixture is then injected into a first reducing zone which is fuel rich in order to begin the combustion process, but retard the formation of nitrogen oxides. The waste gas exiting the reducing zone is deficient in oxygen due to the fuel rich atmosphere in the first reducing zone and cooler due to the water cooling as it enters the second oxidizing zone. In the second oxidizing zone, additional oxygen in the form of air is injected to complete the combustion process.

Abstract: A premix burner has a mixing plenum, a mesh flametrap and a ceramic honeycomb arranged in series. The mixing plenum has inner and outer chambers, with a mixing nozzle for introducing a gaseous fuel concentrically located in the inner chamber. The burner is operated with either high excess air or flue gas recirculation to produce a low temperature flame at a flame face defined by the honeycomb. The thorough premixing of air and fuel ensures a flame with homogeneous air-to-fuel ratios across the flame face, producing low NOx levels. The honeycomb and flametrap also function as flame arrestors to prevent burner flashback. A method for attaining a low temperature, low NOx flame using excess air, with or without flue gas recirculation, is also disclosed.

Abstract: An apparatus having an incineration chamber and at least one burner for oxidizing fumes is provided. First and second regenerators are in fluid communication with the incineration chamber, as is a bypass which introduces unburnt fumes to the incineration chamber without passing them through either of the regenerators. While the fumes are in the bypass, a purging device, including a purge fan and accompanying conduits and valves, introduces a purge gas to either one of the regenerators to force unburnt fumes therefrom. The purged fumes and the purge gas are mixed with the incoming fumes from the bypass in an annular plenum downstream of the purged regenerator before they are introduced to the incineration chamber for oxidation. The flow of incoming fumes to the system may be continuous, even during purging, and the purge fan may also be continuously operated.

Abstract: An apparatus having an incineration chamber and at least one burner for oxidizing fumes is provided. First and second regenerators are in fluid communication with the incineration chamber, as is a bypass which introduces unburnt fumes to the incineration chamber without passing them through either of the regenerators. While the fumes are in the bypass, a purging device, including a purge fan and accompanying conduits and valves, introduces a purge gas to either one of the regenerators to force unburnt fumes therefrom. The purged fumes and the purge gas are mixed with the incoming fumes from the bypass in an annular plenum downstream of the purged regenerator before they are introduced to the incineration chamber for oxidation. The flow of incoming fumes to the system may be continuous, even during purging, and the purge fan may also be continuously operated.

Abstract: Fired heaters, boilers and oilfield steamers include a heater radiant section adjacent a burner. A precombustion chamber is mounted between the burner and the heater radiant section and is surrounded by a combustion air plenum. A plurality of spaced tubes form a perforated combustion chamber and extend from the air plenum axially into the heater radiant section and terminate in line and in converging relationship with the exiting products of combustion. The tubes are protected by refractory members positioned along each tube in abutting end to end relationship. A plurality of openings may be spaced along each tube for progressively staging combustion air.