2309 results about "Nitrogen oxides" patented technology

A combustion analyzer apparatus and method for combustion analysing a sample, the analyzer comprising a combustion chamber (82) for receiving a sample for combustion therein to form combustion products, and a fluid supply apparatus for supplying fluid(s) into the chamber. The fluid supply apparatus (130-140) comprises a nitrogen oxides (NO_x) generating apparatus (140,190,210,240) and is arranged to supply NO_x into the combustion chamber. A yield of sulphur dioxide in the combustion products may thereby be improved. The NO_x generating apparatus may be operated at a raised working temperature. The NO_x generating apparatus may be provided by an ozonator with a supply of nitrogen and oxygen. A Venturi tube arrangement (246) may draw the generated NO_x into a (carrier or oxygen) gas line to the combustion chamber. Ozone may be supplied to the combustion products to convert nitrogen monoxide therein to nitrogen dioxide. The NO_x and ozone may be supplied by a single device (210,240).

An exhaust aftertreatment system comprises an injector for injecting urea water into an exhaust duct, and a denitration catalyst disposed downstream of the injector with respect to a flow of exhaust gas. The exhaust aftertreatment system reduces nitrogen oxides in the exhaust gas by the denitration catalyst while using ammonia produced from the urea water injected from the injector. The urea water is injected along a direction of the flow of the exhaust gas within the exhaust duct, and a porous plate is disposed in multiple stages in a space of the exhaust duct such that droplets of the injected urea water impinge against the porous plate before reaching a wall surface of the exhaust duct. A surface of the porous plate subjected to the impingement of the droplets is arranged to face downstream with respect to the flow of the exhaust gas. Deposition of the urea water is prevented by causing film boiling when the droplets impinge against the porous plate, and the urea water reflected by the porous plate is uniformly dispersed into the exhaust gas. Thus, the urea water is uniformly dispersed into the exhaust gas without increasing a pressure loss of the exhaust gas. The urea water is prevented from depositing on the wall surface and producing a precipitate in the form of a solid.

A catalyst system and a method for reducing nitrogen oxides in an exhaust gas by reduction with a hydrocarbon or oxygen-containing organic compound reducing agent are provided. The catalyst system contains a silver catalyst and a modifier catalyst, where the modifier catalyst contains a modifier oxide, where the modifier oxide is selected from the group consisting of iron oxide, cerium oxide, copper oxide, manganese oxide, chromium oxide, a lanthanide oxide, an actinide oxide, molybdenum oxide, tin oxide, indium oxide, rhenium oxide, tantalum oxide, osmium oxide, barium oxide, calcium oxide, strontium oxide, potassium oxide, vanadium oxide, nickel oxide, tungsten oxide, and mixtures thereof. The modifier oxide is supported on an inorganic oxide support or supports, where at least one of the inorganic oxide supports is an acidic support. The catalyst system of the silver catalyst and the modifier catalyst provides higher NO_x conversion than either the silver catalyst or the modifier catalyst alone.

A method and apparatus to reduce the emissions of an exhaust stream is provided. One feature of the present invention includes a control unit for metering a reagent into the exhaust stream. The control unit adjusts a quantity of the reagent to be metered into the exhaust stream. One embodiment of the present invention concerns a method of removing nitrogen oxides in exhaust gases from a diesel engine by introducing ammonia into the exhaust stream. This Abstract is provided for the sole purpose of complying with the Abstract requirement rules that allow a reader to quickly ascertain the subject matter of the disclosure contained herein. This Abstract is submitted with the explicit understanding that it will not be used to interpret or to limit the scope or the meaning of the claims.

Methods and apparatus for reducing the content of nitrogen oxides in the flue gases produced by the combustion of fuel gas and combustion air introduced into a burner connected to a furnace are provided. The methods basically comprise the steps of conducting the combustion air to the burner, providing a chamber outside of the burner and furnace for mixing flue gases from the furnace with the fuel gas, discharging the fuel gas in the form of a fuel jet into the mixing chamber so that flue gases from the furnace are drawn into the chamber and mixed with and dilute the fuel gas therein and conducting the resulting mixture of flue gases and fuel gas to the burner wherein the mixture is combined with the combustion air and burned in the furnace.

An exhaust emission purifying apparatus has a NOx reduction catalytic converter in an exhaust passage of an engine, for purifying nitrogen oxides in the exhaust gas by reduction with urea aqueous solution; an injection nozzle injecting the urea solution toward an exhaust upstream side of the converter in the exhaust passage; and fins disposed on an exhaust upstream side of an injection position of the urea solution in the injection nozzle, for generating a spiral swirling flow of the gas swirling about a center corresponding to the central axis of an exhaust pipe. The swirling flow generated in the exhaust gas prior to the injection-supply of the urea aqueous solution promotes mixing of the solution with the gas to thereby promote the hydrolysis of the urea solution. And the exhaust gas and ammonia generated from the urea solution are uniformly mixed together.

A combustion control system allows the dramatic reduction of NOx emission levels from industrial combustion processes without having recourse to expensive flue gas clean up methods. The system combines the technique of oscillating combustion with an adapted system for post combustion burn out of the excess of CO resulting from the low-NOx combustion zone. A process for fuel combustion includes generating an oscillating combustion zone by oscillating at least one of the fuel flow and the oxidant flow to achieve a reduced nitrogen oxide emission, selecting oscillating parameters and furnace operating parameters to maximize nitrogen oxide reduction efficiency to the detriment of carbon monoxide production, and combusting carbon monoxide downstream of the oscillating combustion zone by injecting a post combustion oxidant.

A method is provided for producing ammonia (NH₃) and introducing the produced ammonia (NH₃) into an exhaust gas stream as a reduction means for selectively catalytically reducing nitrogen oxides contained in the exhaust gas stream, which is an exhaust stream generated by the combustion process of a motor, a gas turbine, or a burner. The method comprises feeding dry urea from a supply container in a controlled amount to reactor and subjecting the dry urea in the reactor to a sufficiently rapid thermal treatment such that a gas mixture comprising the reaction products of ammonia (NH₃) and isocyanic acid (HCNO) is created. Also, the method comprises immediately catalytically treating the thus produced gas mixture in the presence of water such that the isocyanic acid (HCNO) resulting from the rapid thermal treatment is converted, via quantitative hydrolysis treatment, into ammonia (NH₃) and carbon dioxide (CO₂).

A method of manufacturing polycrystalline abrasive elements consisting of micron, sub-micron or nano-sized ultrahard abrasives dispersed in micron, sub-micron or nano-sized matrix materials. A plurality of ultrahard abrasive particles having vitreophilic surfaces are coated with a matrix precursor material and then treated to render them suitable for sintering. The matrix precursor material can be converted to an oxide, nitride, carbide, oxynitride, oxycarbide, or carbonitride, or an elemental form thereof. The coated ultrahard abrasive particles are consolidated and sintcred at a pressure and temperature at which they are crystallographically or thermodynamically stable.

For improving driver's awareness about emissions and promoting environmental protection, an emission amount notifying device is provided. When such a taxation system becomes effective that a tax is imposed in accordance with an amount of one or more kinds of harmful substances, which include a carbon dioxide, nitrogen oxides, sulphur oxides and hydrocarbons emitted from a vehicle, a sensor determines the emission amounts of respective harmful substances, and a CPU obtains the amount of tax corresponding to the determined emission amounts from a ROM storing tax information related to the tax amounts corresponding to respective displacements, and displays the obtained tax amount on a display device. Further, the CPU sends the information relating to the determined emission amount to a server of authorities from a communication unit for performing tax payment procedures.

A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO₂, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N₂O was not detected (detection limit: 0.6 percent N₂O).

The present invention is generally related to the discovery of the therapeutic benefit of administering gamma-tocopherol and gamma-tocopherol derivatives. More specifically, the use of gamma-tocopherol and racemic LLU-alpha, (S)-LLU-alpha, or gamma-tocopherol derivatives as antioxidants and nitrogen oxide scavengers which treat and prevent high blood pressure, thromboembolic disease, cardiovascular disease, cancer, natriuretic disease, the formation of neuropathological lesions, and a reduced immune system response are disclosed.

A method for controlling an engine exhaust gas system includes the steps of detecting an air-fuel ratio of exhaust gas discharged from an internal engine by an oxygen sensor, controlling the exhaust gas to near the stoichiometric air-fuel ratio by a closed-loop control referring to a resultant signal, and leading the exhaust gas to a three-way catalyst to treat nitrogen oxide, hydrocarbon and carbon monoxide. A nitrogen oxide sensor is provided downstream of the three-way catalyst, and a control value of air-fuel ratio by a closed loop control by the oxygen sensor is corrected to set the nitrogen oxide concentration to a predetermined value in accordance with an output of the nitrogen oxide sensor. The deterioration of the three-way catalyst and/or oxygen sensor is detected by comparing a change in control corrected value for the air-fuel ratio of closed loop control referring to an output of the nitrogen oxide sensor with a predetermined value.

An exhaust gas treatment unit for the selective catalytic reduction of nitrogen oxides under lean exhaust gas conditions which contains at least one catalyst with catalytically active components for selective catalytic reduction (SCR components). The exhaust gas treatment unit is characterised in that the catalyst also contains, in addition to SCR components, at least one storage component for nitrogen oxides (NOx components).

An exhaust system (10) for a lean-burn internal combustion engine comprises a nitrogen oxide (NO_x) absorbent (28), a catalyst (30) for catalyzing the selective catalytic reduction (SCR) of a NO_x with a NO_x specific reactant, first means (18, 22) for introducing a NO_x specific reactant or a precursor thereof into an exhaust gas upstream of the SCR catalyst (30) and means (24) for controlling the introduction of the NO_x-specific reactant or precursor thereof into the exhaust gas via the first introducing means (18, 22), wherein the SCR catalyst (30) is disposed upstream of the NO_x absorbent (28) and optionally with the NO_x absorbent, wherein the control means (24) is arranged to introduce the NO_x-specific reactant or the precursor thereof to exhaust gas via the first introducing means (18, 22) only when the SCR catalyst (30) is active, whereby exhaustion of NO_x-specific reactant to atmosphere is substantially prevented.

An engine controller determines the cost of operating a combustion engine and the cost of operating an emissions after-treatment device. Accordingly, the engine controller adjusts parameters for operation of the engine and the after-treatment device to ensure cost-effective use of the engine and the after-treatment device while complying with exhaust emissions requirements. In particular, the engine controller receives the price of fuel consumed by the engine and the price of reductant used by the after-treatment device to determine the respective cost of operation. Specifically, the fuel is diesel fuel used in a diesel engine; the reductant is urea use in a urea-based Selective Catalytic Reduction (SCR) system; and the regulated exhaust emissions is nitrogen oxide (NOx) emissions. The engine operating parameters may include cooled exhaust gas recirculation airflow, fuel injection timing, fuel injection pressure, and air-to-fuel ratio. The SCR system operating parameters may include the volume of urea injected.

The invention provides a composite smoke denitration catalyst capable of oxidizing zero-valence mercury. The catalyst is composite oxide V2O5-CeO2-WO3/TiO2 or V2O5-CeO2-MoO3/TiO2 based on TiO2 as a carrier, wherein the weight proportion is as follows: the weight percent of TiO2 is 75-100, the weight percent of V is 1-1.5, the weight percent of Ce is 1-5, and the weight percent of W or Mo is 7.5-8.5. The preparation method comprises the following steps: depositing Ce(OH)3 on nano TiO2; dipping ammonium vanadate/ammonium molybdate; and drying and roasting so as to obtain the catalyst; or dipping a commercial SCR (selective catalytic reduction) catalyst in a cerous nitrate aqueous solution, and then drying and roasting. The catalyst provided by the invention maintains the denitraiton efficiency of the original SCR catalyst and simultaneously the oxidation rate of zero-valence mercury is obviously improved, and divalent mercury ions are captured in subsequent dedusting equipment and wet desulphurization system; and the application temperature range of the catalyst is wide, the combination control of emission amounts of nitrogen oxides and mercury in smoke of a fuel coal power plant can be achieved on the promise that the smoke purification facility of the fuel coal power plant is not added.

A nitrogen oxide concentration detector has a first measurement chamber 2 into which is introduced a measurement gas via a first diffusion resistance 1; an oxygen concentration detection electrode 7a for measuring the oxygen concentration in the measurement gas in said first measurement chamber 1; a first oxygen ion pump cell 6 for pumping out oxygen in the measurement gas from said first measurement chamber 2 based on the potential of said oxygen concentration detection electrode 7a; a second measurement chamber 8 into which the gas is introduced from said first measurement chamber 2 via a second diffusion resistance 3; and a second oxygen ion pump cell 8 having a pair of electrodes 8a,8b across which a voltage is applied to decompose NOx in the second measurement chamber 4 to pump out dissociated oxygen to cause a current Ip2 corresponding to the NOx concentration to flow in the second oxygen ion pump cell 8. Variation of NOx concentration is a function of variation of Ip2. The concentration obtained based on the Ip2 is corrected responsive to the oxygen concentration in the measurement gas. Particularly, a coefficient of the variation of the Ip2, gain, in said function is corrected responsive to the oxygen concentration in the measurement gas.

The present invention relates to a technology to purify nitrogen oxides contained in exhaust gas exhausted from lean combustion engines such as diesel engine with ammonia and a selective catalytic reduction type catalyst, and an object of the present invention is to provide a selective catalytic reduction type catalyst which can effectively purify nitrogen oxides even at a low temperature as well as inhibit leak of ammonia, and an exhaust gas purification equipment and a purifying process of exhaust gas using the same.

The present invention is a selective catalytic reduction type catalyst for purifying nitrogen oxides in exhaust gas exhausted from lean combustion engines using ammonia or urea as a reducing agent, it is provided with a selective catalytic reduction type catalyst, characterized in that said catalyst comprises a lower-layer catalyst layer (A) having an oxidative function for nitrogen monoxide (NO) in exhaust gas and an upper-layer catalyst layer (B) having an adsorbing function for ammonia on the surface of a monolithic structure type carrier (C), and that the lower-layer catalyst layer (A) comprises a noble metal component (i), an inorganic base material constituent (ii) and zeolite (iii), and the upper-layer catalyst layer (B) comprises substantially none of component (i) but the component (iii).

The use of organic waste/mineral by-product mixtures as raw materials in the manufacture of cement clinker; as alternative or supplemental fuel sources for heating a kiln used in a cement clinker manufacturing process; and, to reduce nitrogen oxide (NO_x) emissions generated during cement manufacturing processes are disclosed.

The invention belongs to the application technical field, such as gas ionization discharge, plasma chemistry and environment engineering, and relates to a method for reutilizing fume while removing sulfur dioxide and nitrogen oxides by adopting the ozone oxidation method. The method comprises the following steps: ozone gas with a concentration of 40 to 240 g/Nm<3> is fed into a reactor or a flue together with fume at 65 DEG C to 250 DEG C with a smoke dust concentration lower than 40 mg/Nm<3>; the ozone simultaneously oxidizes sulfur dioxide, nitrogen oxides and water in the fume and generates micro-fog drops which are collected into a mixed acid solution after being electrically coagulated; and the mixed acid solution is separated and purified into the sulfuric acid and the nitric acid by adopting a chemical method. The method has the advantages that during the process for simultaneously removing the sulfur dioxide and the nitrogen oxides in the fume, no catalyst is used, no absorbent is added, no byproduct is generated, and no any adverse effect on the environment is generated, and provides a reutilization method for the desulfurization and the denitrification of the fume from coal burning.

A dual system for overall engine emissions control, including prevention of excessive formation of nitrogen oxides and carbon compounds 1) by cooling and humidifying intake air and 2) by restructuring and modifying hydrocarbon fuels, resulting in a more complete combustion, a significant reduction of the latent heat of combustion and increased combustion potency. The invention utilizes one or more ultrasonic devices to create an aqueous vapor from an ultra-pure water supply, said vapor varying in quantity according to engine size and load, having electronic sensors and controls for precision switching, metering and delivery. Simultaneously, while humidifying the intake air, the hydrocarbon fuel is passed from a fuel supply through a catalytic reactor to restructure the hydrocarbon molecules into a more homogeneous, more combustible and cleaner-burning fuel. Thus equipped, said internal combustion engine can be run as a fuel conserving, low emissions prime mover.

A method for measuring nitrogen oxide (NOx) in a gas by decomposing NOx in the gas and measuring an amount of oxygen generated by the decomposition includes: introducing the gas to a first inner space under a first diffusion resistance and connected with an external space, controlling an oxygen partial pressure in an atmosphere in the first inner space to be a predetermined low value at which NO is not decomposed substantially by a main pump means, introducing a controlled atmosphere of the first inner space into a second inner space which is connected with the first inner space and which is under a second diffusion resistance, and converting the atmosphere into an electric signal corresponding to the quantity of oxygen generated by decomposition or reduction of NOx contained in the atmosphere by an electric signal conversion means. A first oxygen concentration detecting means is disposed for detecting an oxygen partial pressure in the second inner space, and a control voltage to be applied to the main pump means is adjusted on the basis of an output of the first oxygen concentration detecting means.

The invention relates to a method for calibrating an electrically controlled diesel engine. The software AutoNOx inputs the emission values of nitrogen oxides at each working condition point in an automatically allocated emission region of the electrically controlled diesel engine according to the complete vehicle running features and the like, the AutoNOx software automatically completes the calculation of the emission design values of nitrogen oxides at each working condition point in an engine emission control region according to the factors of engine operating cycle working condition, thetarget torque curve, the complete engine reliability and the like, the calculation result is used as the emission target of one-dimensional thermodynamics GT-Power engine model, and the GT-Power software obtains the main calibration parameters of the engine through internal computations to form basic calibration in the emission control region of the electrically controlled diesel engine. The method is applicable to the development of performance and emission of various electrically controlled diesel engines, and optimal balance between emission and fuel economy in actual working condition is realized.

The present invention provides a process and a device for regeneration of a nitrogen oxide storage catalyst in the exhaust system of a diesel engine. The process comprises a first and a second regeneration strategy. The first regeneration strategy is applied when the exhaust gas temperature is above a threshold value and comprises changing the air/fuel-ratio from a lean to a rich value during a first regeneration period. The second regeneration strategy is applied when the exhaust gas temperature is below a threshold value and comprises switching the air/fuel-ratio back and forth between lean and rich air/fuel-ratios, forming a sequence of between 2 and 10 rich pulses and between 2 and 10 lean pulses during a second regeneration period.

A platform mounted emissions control unit includes a first system to reduce Particulate Matter (PM), Sulfur Dioxide (SO₂), and Volatile Organic Compounds (VOCs), and a second system to reduce Oxides of Nitrogen (NO_x). The systems serially process exhaust from a mobile or stationary pollution source. In one embodiment, first system is an Ionizing Wet Scrubber (IWS) and the second system is a Selective Catalytic Reducer (SCR), wherein the IWS processes the exhaust first to improve efficiency and service life of the SCR. A generator produces power required by the IWS and SCR, and heat from exhaust of the generator may be used convert urea to ammonia for use by the SCR, and to heat the exhaust flow into the SCR. The SCR may further include a heat exchanger to capture heat in the flow out of the SCR and use the captured heat to heat the flow into the SCR.

A process of operating a nitrogen oxides storage catalyst of an exhaust gas treatment system is described. The process relates to the cycling of the normalized air/fuel ratio lambd-value of the exhaust gas exiting the engine, in which a lambda value greater than 1 represents oxygen-rich, lean burn conditions in which a sorption phase for the sorption of nitrogen oxides takes place; and in which a lambda value less than 1 represents oxygen-poor, rich burn conditions in which a desorption and conversion phase for the desorption and conversion of nitrogen oxides takes place. The lambd-value of the exhaust gas downstream from the storage catalyst is monitored during the desorption and conversion phase to determine the end of the desorption and conversion phase based on the lambd-value falling below a predetermined threshold value. Advantages of the process described include the ability to distinguish permanent from temporary damage to the nitrogen oxides storage catalyst, the ability to compensate for the slow deterioration in storage capacity, and the ability to determine when the storage capacity of the catalyst falls below a certain minimum capacity after which the storage catalyst must be either replaced or thermally treated while still installed in the exhaust gas treatment system.

A method for producing ammonia suitable for use as a reductant in a combustion exhaust gas treatment system is provided that includes the electrolytic hydrolysis of urea under mild conditions. The ammonia generator, which includes an electrolysis apparatus including an electrolytic flow cell, an alkaline electrolyte composition, and a recirculation system, may be operatively coupled to an exhaust gas treatment system to provide an apparatus for reducing nitrogen oxides (NO_x) and/or particulate in exhaust gases.

The invention relates to the use of an emulsified fuel in combination with an engine oil that shows a synergistic effect in reducing emissions such as particulate matter, hydrocarbons and/or nitrogen oxides (NO, NO₂, N₂O, collectively NOx) and/or reducing wear from an engine.

A diesel particulate filter (14) which traps particulate matter and a NOx trap catalyst (13) which traps nitrogen oxides are installed in series in an exhaust passage (10) of a diesel engine (1). A controller (21) calculates a particulate matter deposition amount in the diesel particulate filter (14) (S4). The controller (21), when the particulate matter deposition amount exceeds a first predetermined amount (PM2), prevents sharp increase of the particulate matter deposition amount by prohibiting rich spike where the oxygen concentration of the exhaust gas is controlled to a value corresponding to a rich air-fuel ratio in order to regenerate the NOx trap catalyst (13) (S301, S302, S306), and prevents the particulate matter deposition amount of the diesel particulate filter (14) from reaching a limit.