37results about How to "Reduce the concentration of nitrogen oxides" patented technology

A catalyst article comprises an SCR catalyst and a NOx adsorber catalyst, where each of these catalysts comprise a metal molecular sieve, each with a different metal. The catalyst article can be close coupled with other components to give a NO_X performance advantage from cold start to a combined DOC and SCRF system. Higher NO_X conversion is also shown in under-floor location due to NOx storage before SCR light off and selective NH₃ slip control, allowing higher NH3 fill levels. Systems comprising the catalyst article and methods of using the catalyst article to give improved hydrocarbon and carbon monoxide control, as well as ammonia slip control, are described. The systems can include flow-through or wall-flow monoliths.

Disclosed herein is a catalytic composition comprising a first catalyst composition portion that comprises a zeolite; and a second catalyst composition portion that comprises a catalytic metal disposed upon a porous inorganic substrate; the first catalyst composition portion and the second catalyst composition portion being in an intimate mixture.

A method of decreasing the concentration of nitrogen oxides in a combustion flue gas is disclosed in which the nitrogen reducing agent, either in gaseous form, as small particles, or as small droplets of an aqueous solution, is introduced together with the overfire air in such a way that it mixes with the products of primary combustion along with the overfire air. The nitrogen agent reduced NOx as it passes through the temperature regime that is optimum for the NOx reduction as overfire air and flue gas mix. The transition from low to high temperature effectively eliminates ammonia slip. Additionally, the nitrogen agent may be mixed with the overfire air stream in such a manner that it is optimally shielded from early mixing with the products of primary combustion, where a portion of the overfire air reacts initially with any residual carbon monoxide (CO) that would otherwise interfere with the NOx reduction chemistry.

Provided is a diesel particulate filter capable of removing soot from an exhaust gas while operating at low backpressure, the filter comprising (a) a wall-flow filter substrate having a mean pore size, an inlet side, an outlet side, and a porous interior between the inlet and outlet sides; and (b) a catalyst composition coated from the inlet side of the substrate, wherein the catalyst composition has a d₅₀ particle size distribution, wherein the d₅₀ particle size distribution is less than the mean pore size divided by 4.9, and wherein the outlet side is substantially free of a catalyst coating.

According to principles of the embodiments as disclosed herein, an exhaust gas scrubber system with a two-chamber exhaust gas scrubber is provided which allows for scrubbing of exhaust gases without the use of chemicals. In particular, the process fluid used in the system may be seawater. The exhaust gas scrubber includes a first scrubbing chamber having a fluid spraying system, such as an array of atomizing nozzles that spray atomized seawater into the chamber. The atomized seawater aids in reducing the concentration of sulfur oxides in an exhaust gas stream.

Disclosed is a system which enables the efficient utilization of urea for selective catalytic reduction (SCR) of NO_x by gasifying it and feeding it to a plurality of selective catalytic reduction units associated with a plurality of gas turbines. The invention enables feeding a gasified product of the urea with the ability to fully control separate SCR units without excessive reagent usage or loss of pollution control effectiveness. Controllers determine the amount of reagent required for each turbine to control NO_x emissions and then mixes the gasified urea with the correct amount of carrier gas for efficient operation of each separate SCR unit despite the demand variation between the turbines. In this manner the gasification unit can be properly controlled to provide urea on demand without the need for storing large inventories of ammonia-containing gasses to correct for fluctuations in demand.

An exhaust gas reflux apparatus for an internal combustion engine includes one-way connection means provided between an intake rocker arm and an exhaust rocker arm. The one-way connection means moves between a non-operating position where the intake and exhaust rocker arms are released and an operating position where the intake and exhaust rocker arms are connected to open the exhaust valve only when the intake rocker arm rocks in a valve opening direction of the intake valve. An actuator for switching the one-way connection means between the non-operating position and the operating position is connected to the one-way connection means. Thus, an exhaust gas is sucked into a combustion chamber from an exhaust port using a general exhaust valve in an intake stroke, when exhaust gas reflux is required.

An exhaust gas reflux mechanism for a multipurpose engine includes an exhaust reflux cam formed as an integral part of an single cam of the engine and having a cam lobe profiled to open an exhaust valve while an intake valve stays open during the intake stroke of the engine so that part of an exhaust gas remaining on the side of an exhaust port of the engine is drawn into a combustion chamber during the intake stroke.

In an exhaust emission control system for an internal combustion engine, an exhaust gas recirculation device that operates so as to partially open an exhaust valve to introduce exhaust gas into a cylinder in an intake stroke is provided; a secondary air passage capable of supplying secondary air to an exhaust passage is connected to the exhaust passage; and a one-way valve opened by negative pressure applied from the cylinder to the exhaust passage following an operation of the exhaust gas recirculation device in the intake stroke is provided in the secondary air passage. Accordingly, it is possible to provide an exhaust emission control system for an internal combustion engine that allows secondary air to be supplied into an exhaust passage to reduce HC and CO concentrations and also a NOx concentration in an exhaust gas without using an air pump regardless of an exhaust system structure of the internal combustion engine.

The invention relates to a sintering flue gas SCR denitration and vapor removal system. The system comprises a flue gas condensation vapor-removal defogging dedusting tower, a heat exchange device, ahot-blast stove, an ammonium hydroxide evaporator, a dilution fan, an ammonia injection grid, an SCR denitration reaction device and a flue gas exhaust device. The heat exchange device is arranged between the flue gas condensation vapor-removal defogging dedusting tower and the SCR denitration reaction device. The heat exchange device is used for heat exchange on flue gas to be denitrated or denitrated flue gas to change the temperature, an original flue gas outlet of the heat exchange device is connected with a gas inlet of the SCR denitration reaction device through a second main flue, the hot-blast stove and the ammonia injection grid are arranged in sequence in the flowing direction of the flue gas in the second main flue, and the ammonium hydroxide evaporator and the dilution fan arearranged between the ammonia injection grid and a gas outlet of the SCR denitration reaction device. The sintering flue gas SCR denitration and vapor removal system can carry out SCR denitration on desulfurated sintering flue gas while carrying out vapor removal treatment, the effect of purifying sintering flue gas desulfurated with a wet method is improved, and environmental pollution is reduced.

Provided is a diesel particulate filter capable of removing soot from an exhaust gas while operating at low backpressure, the filter comprising (a) a wall-flow filter substrate having a mean pore size, an inlet side, an outlet side, and a porous interior between the inlet and outlet sides; and (b) a catalyst composition coated from the outlet side of the substrate, wherein the catalyst composition has a d₅₀ particle size distribution, wherein the d₅₀ particle size distribution is greater than or equal to the mean pore size divided by 4.9, and wherein the inlet side is substantially free of a catalyst coating.

In a mechanical apparatus having a diesel engine including a combustion chamber, an intake valve for passing air into the combustion chamber, and an exhaust valve for passing exhaust from the chamber, the mechanical apparatus also having an aftertreatment device configured to treat emissions from the diesel engine, a method of operating the engine is disclosed, wherein the method includes performing at least one combustion in the combustion chamber with a first quantity of fuel, determining a temperature of the aftertreatment device, and if the temperature of the aftertreatment device is equal to or below a preselected temperature threshold, then performing at least one combustion in the combustion chamber with a second, greater quantity of fuel and varying at least one of an intake valve timing and an exhaust valve timing relative to a default valve timing to cause at least one of a compression loss and a pumping loss.

A system includes an exhaust conduit configured to conduct a stream of exhaust gas, wherein the exhaust conduit comprises a selective catalytic reduction catalyst reactor comprising a first catalyst composition; an fuel source configured to introduce a fuel into the exhaust gas stream within the exhaust conduit upstream of the selective catalytic reduction catalyst reactor; a catalytic partial oxidation reformer in fluid communication with the exhaust gas stream and upstream from the selective catalytic reduction catalyst reactor, wherein the catalytic partial oxidation reformer can introduce a hydrogen-rich syngas co-reductant into the exhaust gas stream, when a temperature of the exhaust fluid is less than a determined threshold temperature.

In a boiler having plurality of burners arranged on a furnace wall of a furnace, each burner includes a cylindrical fuel nozzle for injecting a mixture of fuel and carrier gas therefor into the furnace; one or more cylindrical air nozzles provided on the outer circumference of the nozzle for injecting combustion air into the furnace, and a wind box for supplying combustion air to the nozzles in common. The wind box is provided with openings through which combustion air flows in from one direction perpendicular to the axial direction of the burner, and is partitioned by a partition wall to form plurality of parallel flow paths for the air flowing in through the openings. Some of the plurality of flow paths are connected to an upper part of the combustion air nozzle, and the other flow paths are connected to a lower part of the nozzle.

Methods of treating exhaust in a vehicle, and exhaust systems for a vehicle, are disclosed. Example methods may include providing a catalytic converter in an exhaust tailpipe and an oxygen sensor downstream of the catalytic converter. The catalytic converter may be configured to reduce a concentration of a nitrogen oxide (NO_x) present in an exhaust flow through the catalytic converter. The method further includes predicting an increase in an oxygen concentration within the catalytic converter based upon at least one or more real-time vehicle operating parameters, wherein the increase is predicted before a corresponding increase in oxygen concentration is measured by the downstream oxygen sensor. The method may also include adjusting an air-fuel ratio of an engine of the vehicle based upon the predicted increase in oxygen concentration, thereby at least partially preventing the corresponding increase in the oxygen concentration.

The invention relates to equipment for reducing the concentration of nitrogen oxides in flue gas emission of a glass kiln. The equipment comprises at least one high-pressure tank; the input end of theat least one high-pressure tank is connected with a urea liquid output end, and the urea liquid output end is pumped by a pump; an air pressurizing device for air pressurization is installed at the top end of the at least one high-pressure tank, and the air pressurizing device is connected with the at least one high-pressure tank through a compressed air pipeline; and the output end of the at least one high-pressure tank is connected with spray guns through a urea water pipeline. The equipment provided by the invention has the characteristics of a simple structure, ingenious design, easy operation and convenient use.