摘要:
Combustion flue gas containing NOX and SOX is treated to remove NOX in a multistep system in which NOX is reduced in the flue gas stream via selective catalytic reduction or selective non-catalytic reduction with ammonia or an ammonia-forming compound, followed treatment with hydrogen peroxide to remove residual ammonia and, optionally, treatment with an alkali reagent to reduce residual NOX in the flue gas stream. The NOX-depleted flue gas stream may also be subjected to a desulfurization treatment for removal of SOX.
摘要:
A reagent dosing system for dosing a reagent into the exhaust gas stream of an internal combustion engine includes a reagent tank for storing a supply of reagent; an injector module including an atomising dispenser and a positive-displacement metering pump which draws reagent from the reagent tank and delivers it to the dispenser; a supply line coupling the reagent tank to the injector module; a dosing control unit operable to control the injector module to inject reagent into the exhaust gas stream; and an additional priming pump arranged, in use, to urge reagent along the supply line toward the injector module under selected conditions.
摘要:
An exhaust gas purification system provided with an NOX purification catalyst reducing the amount of use of precious metals and/or able to exhibit an NOX purification performance at a low temperature and/or in an oxidizing atmosphere and having an NOX purification performance even for an exhaust gas composition containing hydrocarbons and oxygen together with a low temperature and/or oxidizing atmosphere, that is, an exhaust gas purification system provided with an NOX purification catalyst provided in an exhaust gas passage and comprised of carrier particles on which nanoparticles in which gold atoms and nickel atoms are included in a state in close proximity are carried and an oxidation catalyst oxidizing hydrocarbons in exhaust gas at a position at an upstream side of the NOX purification catalyst.
摘要:
An exhaust system (10) for a lean-burn internal combustion engine (12) comprises a first substrate monolith (16) comprising a catalyst for oxidising nitric oxide (NO) comprising a catalytic oxidation component followed downstream by a second substrate monolith (18) which is a wall-flow filter having inlet channels and outlet channels, wherein the inlet channels comprise a NOx absorber catalyst (20) and the outlet channels comprise a catalyst for selective catalytic reduction (22) of nitrogen oxides with nitrogenous reductant.
摘要:
A process for reducing nitrogen oxides and halogenated organic compounds in an incineration plant having at least one combustion chamber. The process comprises separating out fly ash using a dust collector. Water is added to and hydrochloric acid separated out in a first acid-operated scrubber. Water and ammonia are added so as to separate out sulphur dioxide in a second neutral or slightly acid-operated scrubber so as to form ammonium sulphite, a portion of the ammonium sulphite thereby reacts with oxygen so as to form an aqueous ammonium sulphate/ammonium sulphite solution. The aqueous ammonium sulphate/ammonium sulphite solution is introduced into an oxygen-containing smoke gas downstream of a secondary gas introduction area so as to decompose the ammonium sulphate and ammonium sulphite so as to form ammonia and sulphur dioxide. Ammonia, oxygen and nitrogen oxides are reduced in the smoke gas by selective non-catalytic reduction so as to produce nitrogen and water, the chloride-containing fly ash in the smoke gas reacting with sulphur dioxide, water and oxygen so as to produce sulphates and hydrochloric acid.
摘要:
A system and method for treating flue gas that results from a combustion process is described. The method and system includes injecting an SOx absorbent reagent into the flue gas pathway at a point upstream of a selective catalytic reduction (SCR) reactor exit and downstream of a boiler exit. The method and system may also include injecting a NOx reducing agent simultaneously with the SOx absorbent reagent, either via the same injection system or via a second injection system located nearby the SOx absorbent reagent injection system. Injection of the SOx at a point upstream of the SCR reactor exit simplifies the injection systems, gas distribution systems, and physical and/or computational fluid dynamics modeling.
摘要:
A method is described for treating a gas including nitrogen oxides (NOx). The method can include conducting a reduction reaction of the nitrogen oxides with a nitrogen reducing agent. Further described, is a catalyst used for the reduction reaction which is a catalytic system including a composition based on cerium oxide and including niobium oxide in a proportion by a mass of from 2% to 20%.
摘要:
An exhaust purification system for an internal combustion engine capable of lean-burn driving comprises: an NSR catalyst disposed in an exhaust passageway; an SCR disposed downstream of the NSR catalyst; a NOx sensor, disposed downstream of the SCR, for producing output in response to NOx concentration; and rich-spike means for causing a rich-spike. When the NOx sensor has produced output indicative of a NOx concentration higher than a given NOx concentration, the system increases the amount of the NOx contained in the exhaust gas discharged during the rich-spike. Under a given high-load condition, the air-fuel ratio is made stoichiometric during the rich-spike caused at a particular timing. Under a given low-load condition, the amount of exhaust gas is increased during the rich-spike.
摘要:
In an internal combustion engine, an SOX trap catalyst (13) which traps SOX contained in the exhaust gas is arranged upstream of an NOX storing catalyst (15) in an engine exhaust passage. When the NOX storing catalyst (15) should release NOX, auxiliary fuel is injected into a combustion chamber (2) at a combustible timing after the completion of injection of fuel into the combustion chamber (2) for generating the engine output. At this time, the auxiliary fuel is injected so that the air-fuel ratio A/F of the combustion gas in the combustion chamber (2) does not become below a minimum allowable air-fuel ratio M where SOX trapped at the SOX trap catalyst (13) will not be released.
摘要:
An exhaust gas purifying system for an internal combustion engine has a relatively simple construction and is capable of accurately calculating the amount of SOx deposited on a NOx catalyst.A CO2 sensor having a detection electrode containing BaCO3 is disposed in an intake pipe at a location downstream of a confluent portion. A catalyst SOx deposition amount is calculated according to an EGR rate and a sensor deposition amount, based on the fact that the relationship between the sensor deposition amount detected by the CO2 sensor and the catalyst SOx deposition amount is determined according to the EGR rate.