The method of purification of gases from nitrogen oxides
(57) Abstract:The invention can be used for cleaning of gases from nitrogen oxides produced during combustion of hydrocarbon fuel in various power plants. The flow of exhaust gases fed into the mixer, where ejectives gas diluent, which are used as the exhaust gases after treatment with the reducing agent, the amount of which is regulated depending on the temperature of the main flow of exhaust gases. The method allows to increase the efficiency of the exhaust gases from nitrogen oxides. 1 C.p. f-crystals, 1 tab., 1 Il. The invention relates to the protection of the environment, to the protection of air from the nitrogen oxides produced during combustion of hydrocarbon fuel in various power plants: combustion engines, gas turbine engines, boilers, CHP and others.The efficiency of cleaning of exhaust gases from nitrogen oxides can be improved by entering into the flow of EXHAUST gas diluent . However, in this method, the uneven distribution of ammonia in the stream can significantly reduce the concentration of nitrogen oxides in the EXHAUST gas.A known method of cleaning flue GAMM of this method is the need for a preliminary calculation of the feed rate recovery of the mixture, as well as maintaining a constant total mass flow for uniform distribution of the ammonia.The aim of the invention is improved method of purification of EXHAUST gas from the nitrogen oxides. This objective is achieved in that the flow of the EXHAUST gas of known temperature is fed into the mixer with built-in ejector, through the Central hole which is again part of the purified EXHAUST gas flow, in the zone of intense mixing of the supplied reducing agent, for example ammonia, the amount of which is regulated depending on the initial temperature of the EXHAUST gas flow.The required flow rate in the mixer and, consequently, the reduction time of the process established by the sizing structure of the device depending on the source data power plant.Comparative analysis of the prototype shows that the proposed solution differs from the known fact that the amount of reducing agent is ammonia, adjustable, depending on the temperature of the stream fed to the mixer, where the main flow of the EXHAUST gas of known temperature ejectives gas diluent, which is used as the EXHAUST gas after treatment.The content of nitrogen oxides and uniform distribution of ammonia in the EXHAUST gas flow is possible through the use of the gas ejector. Ejected the main flow of the EXHAUST gas is captured by a high-pressure stream of purified EXHAUST gas and intensively mixed with fed into the mixing zone of ammonia.The desired depth of penetration and the degree of turbulence is defined by the ratio of the areas obtained section ejecting streams and the ejected gases. When this is achieved rapid and uniform distribution of the reducing agent in the mixture of the gas stream.The amount of recovery of the mixture is adjusted depending on the temperature of the EXHAUST gas installation, at the same time regulated thermoprobes the main flow of the EXHAUST gas.These conditions allow us to provide more effective cleaning of EXHAUST gas from nitrogen oxides compared to the prototype.The comparison of the proposed solutions not only prototype, but also with other technical solutions in this field of technology is not allowed to reveal in them the features distinguishing the claimed solution to the prototype that allows to make a conclusion on compliance with the criteria of the invention "inventive step".The proposed method is implemented on the installation, the scheme of which is shown in the drawing. The scheme contains a mixer 1 having termoizolatii 8. In the rarefaction zone of the mixer 1 is gas-reducing agent is ammonia, from the tank (cylinder) 6 to line 5 through the valve 9, the adjustable parameters of the temperature sensor 10 of the EXHAUST gas inlet pipe 7.Implementation of the above method is as follows. The flow of the EXHAUST gas flows through the inlet pipe 7 into the mixer 1, encountering an obstacle in the form of ejector disc 2 creates a vacuum behind the disk, resulting in line 4 in the Central hole 3 of outlet 8 is sucked portion of the cleaned EXHAUST gas flow. Concurrently, the pipe 5 is supplied gas reductant. The invention is illustrated by examples of calculation shown in the table.Sources of information
1. European patent N 0294658, 01 D 53/34, 1988.2. EN N 2008079 C1, B 01 D 53/34, 1994. 1. The method of gas purification from nitrogen oxides by neutralization in a reducing environment with gas diluent, wherein the amount of reducing agent, adjustable, depending on the temperature of the flow of exhaust gases fed to the mixer, where ejectives gas diluent, which are used as the exhaust gases after purification, with the main flow of exhaust gases.IAK.
FIELD: physical or chemical processes and apparatus.
SUBSTANCE: method comprises flowing air through the chemical absorber of nitrogen acids that is composed of chemically absorbing base that absorbs nitrogen dioxide and sorbent-oxidizer that oxidizes nitrogen mono-acid up to nitrogen dioxide. The chemical absorber is made of n pairs of layers of chemically absorbing base and sorbent-oxidizer. Upon flowing throughout n pairs of the layers, the initial concentration of the nitrogen dioxide drops by a factor of 3n, where n is the total number of pairs of the layers.
EFFECT: reduced cost and enhanced efficiency.
2 cl, 1 tbl
FIELD: methods of purification of flue gases.
SUBSTANCE: the invention is pertaining to the method of purification of flue gases and may be used to decrease the outbursts of nitrogen oxide with the help of the method of the high-temperature selective non-catalytic reduction. The method provides for feeding of the previously prepared steam-gaseous reduction mixture into the gas flue of the flue gas burning aggregate with the temperature of the flow of the purification gases of 700-1200°C. At that the steam-gaseous reduction admixture is prepared in the connected to the gas flue high-speed reactor during 0.5-5 seconds by introduction of a water solution of carbamide with a superheated steam at the pressure of 3-10 atm. Concentration of the water solution of carbamide makes 20-40 mass %. The time of the contact of the water solution of carbamide with the superheated steam predominantly makes 0,5-2 seconds. The pressure in the reactor predominantly makes 3-6 atm. The temperature of the superheated steam makes 200-400°C. The invention ensures simplification of the production process of purification of the effluent gases from nitrogen oxides, to increase the level of purification of such a gas in the broad range of the temperatures of the purified combustion products, and also to decrease significantly the share of the secondary contaminant - ammonia, in the purified gases.
EFFECT: the invention ensures simplification of the production process of the effluent gases purification from nitrogen oxides, to increase the level of purification of the gases in the broad range of the temperatures of the purified combustion products, to decrease significantly the share of the secondary contaminant - ammonia in the purified gases.
5 cl, 2 ex, 1 dwg, 2 tbl
FIELD: chemical industry; methods of neutralization and a utilization of the aggressive chemical compounds.
SUBSTANCE: the invention is pertaining to the field of neutralization and a utilization of the aggressive chemical compounds, in particular, the saturated with the anhydrides acid-containing compounds and wastes. The neutralization is applied to the smoke mixture containing the sulfuric anhydride and chlorosulfonic acid, or the oxidizing agent of the rocket propellant based on of the nitric acid containing a dimer of the nitrogen dioxide. For neutralization use the hydrolyzed dispersible aluminosilicates based of the natural clays selected from: hydromicaceous Cambrian clay, montmorillonite clay, kaolinite clay or on the basis of their mixtures. At that the hydrolyzed dispersible aluminosilicates, which are taken at least in equal shares with an aggressive chemical compound, are prepared at the following ratio of components (in mass shares): a dry substance - 1.0-2.5, water - 1.0. The invention allows to neutralize the aggressive wastes and to produce the useful product with the sorption activity.
EFFECT: the invention ensures neutralization of the aggressive wastes and production of the useful product with the sorption activity.
3 cl, 2 ex, 6 tbl
FIELD: gas purification.
SUBSTANCE: method comprises treating the flow of chimney gas in the high-temperature zone with a temperature of 700-1200°C by means of gas reducing mixture that is preliminary is produced by thermal decomposition of solid carbamide out of the zone for treating the gas and is supplied to the zone of purification by the gas-carrier. The carbamide is decomposed by rising its temperature from 100 to 600°C. The rate of the temperature rise is 5-40°C/min and 35-40°C/min for the temperature range from 100 to 400°C and temperature higher than 400°C, respectively.
EFFECT: simplified method.
3 cl, 1 dwg, 1 tbl
FIELD: non-catalytic method of reduction of nitrogen oxide emission in combustion product flow.
SUBSTANCE: proposed method includes bringing in contact effective amount of at least one nitrile compound fed to combustion apparatus in form of separate liquid flow or in form of separate gas flow with flow of wastes fed to combustion apparatus in non-separated form, additional fuel flow and air at temperature sufficient for reduction of NOx emission in flow of combustion products.
EFFECT: reduction of nitrogen oxide emission in combustion product flow.
13 cl, 4 tbl, 3 ex
FIELD: cleaning waste flue gases of tubular furnaces used in power technological plants of ammonia production process from nitrogen oxides.
SUBSTANCE: proposed method includes mixing flue gases with air and ammonia-containing reductant. Used as ammonia-containing reductant are synthetic gases of ammonia production process of the following composition, mass-%: ammonia, 20-30; methane, 18-24; hydrogen, 25-35; argon, 3.8-4.8; the remainder being nitrogen. Selective catalytic reduction of nitrogen oxides of flue gases is performed in reactor at temperature of 240-450°C with the use of tungsten-vanadium catalyst. Proposed method makes it possible to clean flue gases to 91%.
EFFECT: high degree of cleaning.
FIELD: cleaning exhaust gases from nitrogen oxides in industrial plants by means of selective catalytic cleaning with the use of ammonia.
SUBSTANCE: proposed method includes reduction of nitrogen oxides by ammonia on catalyst in presence of hydrogen. Before delivery to catalyst, exhaust gases are mixed with purge gases from the ammonia synthesis cycle. Content of hydrogen in mixture is maintained below low limit of ignition. Purge gases are enriched with ammonia by mixing them with ammonia synthesis gases.
EFFECT: reduced consumption of ammonia; enhanced mixing of exhaust gases with ammonia; reduced emissions of ammonia into atmosphere; reduced power requirements.
FIELD: inorganic synthesis catalysts.
SUBSTANCE: decomposition if N2O under Ostwald process conditions at 750-1000°C and pressure 0.9-15 bar is conducted on catalyst, which comprises (A) support composed of α-Al2O3, ZrO2, SeO2, or mixture thereof and (B) supported coating composed of rhodium or rhodium oxide, or mixed Pd-Rh catalyst. Apparatus wherein N2O is decomposed under Ostwald process conditions on the above-defined catalyst is also described. Catalyst is disposed successively downstream of catalyst grids in direction of stream of NH3 to be oxidized.
EFFECT: increased catalyst activity.
8 cl, 2 tbl, 3 ex
FIELD: chemical industry; other industries; methods of the selective non-catalytic purification of the flue gases from nitrogen oxides.
SUBSTANCE: the invention is pertaining to the processes of the selective non-catalytic purification of the flue gases from nitrogen oxides and may be used for reduction of the contents of the nitrogen oxides in the low-temperature flue gases from the fuel-burning installations. The method of the selective non-catalytic purification of the flue gases from nitrogen oxides provides for feeding in the flow of the end flue gases having the temperature 200-700°С of the gaseous reduction mixture previously produced by the joint thermal decomposing of carbamide and hydrogen peroxide at the temperature of 150-500°С. For production of the gaseous reduction mixture they use either the water solutions of carbamide peroxihydrate or carbamide and hydrogen pyroxide, either carbamide peroxihydrate in the solid kind. The reduction gas mixture is fed by means of the carrier gas, in the capacity of which use the water steam, the flue gases, the compressed air, nitrogen. The concentration of the water solutions of carbamide and hydrogen peroxide makes 1-40 mass % and 0.5-20 mass %. The technical result of the invention is the increase of efficiency of purification of the flue gases from nitrogen at the low temperatures without formation of the secondary contaminants.
EFFECT: the invention ensures the increased efficiency of purification of the flue gases from nitrogen at the low temperatures without formation of the secondary contaminants.
4 cl, 3 tbl, 2 ex
SUBSTANCE: principle refers to catalyst and method of complex purification of waste gases of different production, heat and power utilities, automobile transport, which works on natural gas (methane). Described is a method of complex purification of effluent gases from nitrogen oxides, carbon oxide and hydrocarbons and it involves passing the effluent gases at temperatures 455-600°C through a layer of mechanical mixture of nickel chromium oxide industrial catalyst a copper zink nickel industrial catalyst in a volume composition of 1:1 to 20:1 respectively. To the effluent gases, methane up to a volume composition of CH4/O2 0.07-0.15 can be added before passing it through the catalyst layer. Nickel chromium oxide industrial catalyst contains NiO 38-42 %; ZnO 28-32 %; NiO 4-6 % and not less than Al2O3 17 % masses.
EFFECT: increasing of the purifying index of effluent gases.
3 cl, 4 ex