TH8960B - Methods for gas purification containing nitrogen oxide and equipment for gas purification in steam generators - Google Patents

Abstract

A method of reducing the nitrogen oxide level in the fuel gas emitted by the unit. Burned by introducing redundant gas with nitrogen oxide in the first reduction step. And the second will be arranged The first reduction step is a non-catalytic step (ie at temperatures above 800 ํ C) while the first reduction step is a catalytic step (ie, at temperatures around 300-400 ํ C .) The steam generating boiler with the improved nitrogen reduction facility is Arranged as well The amount of nitrogen oxide in the hot gas is reduced in the combustion of the phase. First and second reduction While steam generating in a boiler system, the steam generation has a significant effect on gases that are free from nitrogen oxides. While eliminating the possibility of NH3 (or other reducers) emanating in the exhausted fuel gas. Heat transfer in The recirculation part, as it was used, was used to create a constant temperature condition for the accelerated reduction.

Claims (3)

1. Method of purification of combustion gases from a steam generator plant. This plant consists of a fuel reaction chamber. and the rotation part The fuel gas recirculation is functionally connected to the reaction chamber. This recirculation section provides the heat transfer part for the extraction of heat from that gas. burning in the reaction chamber resulting in Producing hot gas containing nitrogen oxides. (b) Supplying this hot gas from the reaction chamber and introducing this hot gas into in the recirculation section (c) cooling the gas in the fuel gas recirculation section; (d) reduction of nitrogen oxides in the first reduction stage by hot gas heating. into contact with the hydrides, and, consequently, (e) the reduction of nitrogen oxides in the second reduction stage by forcing the gas. with a reducing agent of the first reduction step to catalyzed NOx reduction in the fuel gas recirculation section while maintaining the gas temperature in The second reduction stage within the chamber is approximately + - 25 °C of the working temperature. Max of the accelerator The heat transfer is arranged in the convection section. and where step (e) is performed after the gas has passed through the heat transfer surface of the feedstock of the economizer and step (d) before the gas is passed through the heat transfer surface. of Raw material saver 3. The method according to claim 1, where the raw material saver has a surface. The heat transfer is arranged in the convection section. and where procedure (e) is performed before that gas passes through the heat transfer surface of the material saver. Allow the gas to cool in the convection section at a temperature < 500 ° C. Heat the steam of the convection section before the catalytic reduction in the second reduction stage. Let the gas be cooled in the convection section to approximately 300-400 °C before the second reduction step and step (d) is performed before step (c). 1, by the next stage of temperature treatment of gas in the second reduction stage at a level within + - 25 °C of the maximum operating temperature. of the catalyst used in the second reduction stage by controlling the flow rate of the catalyst. The heat transfer medium in the convection section prior to the second reduction procedure 7. Method of claim 6, where procedure (d) is to be performed by injection. The reducing agent comes into contact with the hot gas at one or more positions corresponding to the support. Steam generation load of a steam generating plant 8. Method according to Claim 5, where procedure (d) is to be carried out by The hot gas comes into contact with the reducing agent at a temperature of > 800 °C to effect NOx reduction in the hot gas without catalyst. ) will be implemented in order to Reduce any excess amount of reducing agent in the hot gas before it leaves the recirculation section. 1 0. Claim method 1, where procedure (e) is to be performed in order to Pass that hot gas through the catalyst bake above a valuable linear flow distance. less than about 2 m. 1 1. Method according to claim 1 where the procedure (a)-(e) will be treated until Even the pressure loss of the catalytic operation of the stage (e) is less than 50% of the pressure loss for conventional catalytic reduction 1 2. Method according to claim 1. where the pressure loss of practice The catalysis in step (e) is less than approximately 400 l\'a 1 3. The method according to claim 1, where the reducing agent is introduced into step (d), will was selected from a group consisting of Substances containing amines, ammonia, urea or ammonia Pre-produced 1 4. Methods of purifying gas combustion from the factory fluidized bed steam generation The steam generating plant consists of a fluidized bed reaction chamber. Particle separator connected to the reaction chamber and the fuel gas recirculation section which is connected to the particle separator and has a heat transfer section for the heat extraction. for extracting heat from gas The method consists of the steps of (a) maintaining the combustion reaction in the fluidized bed of solids in the chamber. The fluidized bed reaction results in the production of hot fuel gas. (b) The supply of hot gas and particles carried simultaneously from the reaction chamber. and the introduction of this gas and particles into the particle separator. (c) Separation of particles from the gas in the separator (d) in the first reduction stage. The hot gas is brought into contact with the reducing agent, which results in a reduction of the NOx content of this gas under no catalyst conditions. reaction, then (e) cooling the gas in the fuel gas recirculation section, and (f) in the second reduction stage. Forcing the gas with the reducing agent of the procedure First reduction goes to catalytic NOx reduction in the fuel gas recirculation section. fire after the procedure (e) while maintaining the gas temperature. in the second reduction step within the maximum operating temperature of the accelerator 1 5. Method of claim 14, where this plant includes economizers Objects with heat transfer surfaces in the convection section and where step (f) is performed after the gas has passed through the heat transfer surface of the apparatus. Saving raw materials 1 6. The method according to Claim 14 wherein the plant includes economizers. Raw materials with charcoal surface pour heat in the circulating section. and where step (f) is to be performed before that gas passes through the heating surface of the raw material economizer 1. 7. Method of claim 14, where step (e) will be implemented in order to Cool the gas in the convection part at a temperature < 500 ° C by the feeding surface. Steam heat of the convection section prior to catalyst reduction in step (f) 1 8. Claim method 17, where step (e) is to be performed for The gas is cooled in the recirculation section from temperature > 800 °C to approximately 300-400 °C before catalyst reduction in step (f) 1 9. Claim method 14 also consists of the process of healing. The gas temperature in the second reduction stage is within + - 25 ° C of the cooking temperature. The maximum work of the catalyst used in the second reduction stage is by controlling the flow rate. of the heat transfer medium in the recirculating section before the second step 2 0. Claim method 14, where step (d) is to be performed by The hot gas is brought in contact with the reducing agent at a temperature of > 800 °C to produce an acidic NOx effect in the hot gas without catalyst 2. 1. Claim method, Article 19, where procedure (d) shall be performed by Inject the reducing agent into contact with the hot gas at one or more positions corresponding to the secondary. Take the steam generator load of the steam generator plant 2 2. The method of claim 14, where procedure (f) shall be performed in order to: Pass that hot gas through the catalyst bake over a valuable linear flow distance. less than about 2 m 2 3. The method specified in Claim Article 14, where procedure (d) shall be performed at temperatures above > 800 °C in order to reduce the NOx content of that gas to approximately 60 ppm or less and where step (f) is performed at approximately 300-400 °C to to reduce the NOx content of that gas to approximately 20 ppm or less, and until the possibility of NH3 emission or a substantially similar reducing agent is eliminated.