Abstract:
PURPOSE:To reduce the production of NOX without an increase in an unburnt matter even if high fuel ratio coal is partially used, by a method wherein, in a burning device having burners in a multistage and after-air ports thereabove, combustion is effected in a way that pulverized coal with a low fuel ratio is fed to burners at a lower and a middle stage part, and pulverzied coal with a high fuel ratio is supplied to burners at a middle stage part. CONSTITUTION:Since flammable low fuel ratio coal is supplied to a first stage burner 3, althrough there is high-value radiation cooling at a hopper part 12 located at a lower furnace 1, excellent combustion takes place. Further, since low fuel coal, which is susceptible to production of reducing radial well suited for reduction of NOX resulting from incomplete combustion of a volatile component, is supplied to a third burner 5 as well, excellent reduction of NOX generated at the combustion zone of the burners 3 and 4 can be conducted. Meanwhile, though fire-retardant high fuel ratio coal is supplied to burners 4 at a second stage, since the combustion zone of the burner 4 is held at high temperature condition by the combustion radiation heat of the burners 3 and 5, combustion of high fuel ratio coal is improved.
Abstract:
A staged-coal injection procedure for coal-fired boilers used in power generation. The procedure includes the steps of combusting a first type of coal in a first zone (115) of a furnace (120); and combusting a second type of coal in a second zone (114) of the furnace (120). The second zone is at a position separate from the first zone.
Abstract:
The proposed low-emission vortex furnace is intended for use in burning organic fuel and can be used most effectively for burning dust. The proposed low-emission vortex furnace comprises a combustion chamber (1) with a cold prismatic funnel (5) which has a slit aperture, and a device (7) positioned underneath the funnel and used for introducing the bottom blast. The furnace contains at least one burner (2) in the form of at least two fuel-air mixture feed ducts (2a, 2b), one duct lying above the other. Each of the ducts (2a, 2b) is provided with a device (3, 4) for adjusting the fuel/air ratio; this device ensures that the ratio of air to fuel in the upper duct (2a) is always higher than in the lower duct (2b). The longitudinal axes of the ducts (2a, 2b) are advantageously inclined so that the angle between the longitudinal axis of the lower duct (2b) and the projection of that axis onto the furnace wall is less than in the case of the upper duct (2a). The furnace may also be provided with a device (8) for feeding fuel of a particular fractional composition into each duct. During operation of this furnace, three operational zones are formed in the furnace chamber, namely, an ignition and active combustion zone; a reduction zone; and a re-heating zone. This reduces the quantities of nitrogen oxides produced while ensuring that the furnace is highly economical to operate.
Abstract:
Beim Schmelzen von Glas aus Beschickungsgut (12) in Wannenöfen (1) mit Brennern (11) und mit Regeneratoren (6) für die Wiedergewinnung von Abwärme werden im Bereich der Flammenwurzeln Sauerstoff und Primärbrennstoffe zur Deckung des Wärmebedarfs für den Schmelzprozeß bei schwach unterstöchiometrischen Bedingungen zugeführt. Zur weiteren Reduzierung der Gehalte an NO x und CO in den Abgasen durch Nachverbrennung bzw. Nachoxidation jenseits der Flammenenden werden Sekundärbrennstoffe und stromabwärts weitere Luft zugeführt, um durch den Sekundärbrennstoff in oder über der Kammergitterung (5a, 6a) NO x zu reduzieren und stromabwärt durch die Luftzufuhr eine Nachverbrennung bzw. Nachoxidation durchzuführen, so daß schließlich eine zumindest weitgehend stöchiometrische Verbrennung erfolgt. Die Abgase werden vor dem Eintritt in einen Abgaskamin (15) zur Vorwärmung des Beschickungsguts (12) in mindestens einem Gutvorwärmer (13) verwendet. Um eine nahezu vollständige Rückgewinnung der Energieinhalte der Brennstoffe und einen kontinuierlichen Strom des Beschickungsguts zu gewährleisten, wird die Temperatur der aus den Regeneratoren (6) stammenden Abgase vor dem Eintritt in den mindestens einen Gutvorwärmer (13) gemessen, und die Menge der Sekundärbrennstoffe wird in Abhängigkeit von den gemessenen Temperaturwerten geregelt.
Abstract:
The present invention is related to methods and systems for preventing the release of nitrogen oxides with combustion flue gases emitted to the atmosphere. The invention is specifically directed to the removal of nitric oxide, nitrogen dioxide, and nitrous oxide from flue gas in stationary combustion systems. The methods of the invention improve efficiency of conventional reburning and advanced reburning processes by two key improvements, including the injection of a reducing agent into the reburning zone (16) and the use of promoters, which considerably enhance NOx control. The promoters are metal-containing compounds that can be added to the reducing agents. These improvements allow either one or two stages of reducing agent injection for greater NOx control (50).
Abstract:
The proposed low-emission vortex furnace is intended for use in burning organic fuel and can be used most effectively for burning dust. The proposed low-emission vortex furnace comprises a combustion chamber (1) with a cold prismatic funnel (5) which has a slit aperture, and a device (7) positioned underneath the funnel and used for introducing the bottom blast. The furnace contains at least one burner (2) in the form of at least two fuel-air mixture feed ducts (2a, 2b), one duct lying above the other. Each of the ducts (2a, 2b) is provided with a device (3, 4) for adjusting the fuel/air ratio; this device ensures that the ratio of air to fuel in the upper duct (2a) is always higher than in the lower duct (2b). The longitudinal axes of the ducts (2a, 2b) are advantageously inclined so that the angle between the longitudinal axis of the lower duct (2b) and the projection of that axis onto the furnace wall is less than in the case of the upper duct (2a). The furnace may also be provided with a device (8) for feeding fuel of a particular fractional composition into each duct. During operation of this furnace, three operational zones are formed in the furnace chamber, namely, an ignition and active combustion zone; a reduction zone; and a re-heating zone. This reduces the quantities of nitrogen oxides produced while ensuring that the furnace is highly economical to operate.
Abstract:
A pulverized coal combustion burner includes a pulverized coal nozzle (1), and secondary and tertiary air nozzles (70,80) provided in concentric relation to the pulverized coal nozzle. A flame stabilizing ring (5) is provided at an outlet end of the pulverized coal nozzle. A separation wall (2) is provided within the pulverized coal nozzle to divide a passage in this nozzle into two passages. A pulverized coal/air mixture flows straight through the two passages, so that recirculation flows of the pulverized coal/air mixture are formed in proximity to the outlet end of the pulverized coal nozzle. As a result, the ignitability of the pulverized coal, as well as a combustion rate, is enhanced, thereby reducing the amount of discharge of NOx.