Patent Application
20080245055
The present disclosure relates generally to atomizers, and specifically, to atomizing nozzles used with liquid agents in emission abatement systems.
Atomizers are typically used in an emission abatement system for atomizing a liquid agent to be used for abating emissions such as those present in exhaust gases produced through operation of an internal combustion engine. For example, hydrocarbon fuel may be atomized for use in an exothermic reaction for regenerating a soot particulate filter that traps soot present in the exhaust gases of an engine. Urea may be atomized and used as a reductant in selective catalytic reduction catalysts, which reduce the oxides of nitrogen typically present in the engine exhaust. Pressurized air can be mixed with a particular liquid agent at a location upstream of the an atomizing nozzle used to ultimately deliver an atomized spray for use in an emission abatement system.
According to one aspect of the disclosure, a method of operating an emission abatement system may comprise advancing a liquid agent to an atomizing nozzle and advancing pressurized air to the atomizing nozzle. The method may further include impinging the pressurized air on the liquid agent at a tip of the atomizing nozzle to shear liquid agent particles from the liquid agent. The method may further include advancing the liquid agent particles through the atomizing nozzle to an emission abatement device.
According to another aspect of the disclosure, an emission abatement system may include an atomizing nozzle. The system may further include a supply of liquid being deliverable to the nozzle through a liquid agent line. The system may further include a supply of pressurized air being deliverable to the atomizing nozzle to impinge on the liquid agent at a tip of the atomizing nozzle. The system may further include an emission abatement device disposed downstream of the atomizing nozzle.
According to another aspect of the disclosure, an atomizing apparatus may include a body being substantially cylindrical in shape, and having an opening concentric with a circular cross-section and the opening being disposed therethrough. The body may further include a number of air channels disposed radially therethrough and a number of first liquid agent channels disposed therethrough. Each first liquid agent channel may be in fluid communication with one of the number of air channels. The apparatus may further include a supply of liquid agent in fluid communication with each of the number of first liquid agent channels and a supply of pressurized air in fluid communication with each of the number of air channels. The apparatus may further include a number of atomizing nozzles with each nozzle being disposed at an end of one of the number of air channels and each nozzle being directed toward the opening in the body.
According to another aspect of the disclosure, an atomizing apparatus may include a first and second atomizing nozzle, a supply of liquid agent, and a first and second supply of pressurized air. The apparatus may further include an air line having the first atomizing nozzle disposed at an end thereof and being in fluid communication with the first supply of pressurized air. The apparatus may further include a liquid agent line disposed within the air line. The liquid agent line may have the second atomizing nozzle disposed at an end thereof and being in fluid communication with the supply of liquid agent and the second supply of pressurized air.
The detailed description particularly refers to the accompanying figures in which:
As will herein be described in more detail,
An atomizer 14 and an emission abatement device 16 are disposed in the exhaust pipe 12 with the atomizer 14 being located upstream of the emission abatement device 16. The atomizer 14 may receive a mixture of a liquid agent and air to produce an atomized spray to be subsequently used for emissions abatement. In this exemplary embodiment, the atomizer 14 receives a liquid agent from a liquid agent supply 18 through a liquid agent line 20 and pressurized air from an air supply 22 through an air line 24. An optional air supply 19 may be implemented to mix air with the liquid agent prior to being advanced to the atomizer 14 through a liquid agent line 20.
In this exemplary embodiment, pressurized air from the air supply 22 may impinge the liquid agent (or agent/air mixture) just prior to being injected from the atomizer 14 into the exhaust pipe 12, which causes the liquid agent to be sheared into smaller particles than would be created through impingement occurring at a point further upstream of the liquid agent line 20 as is conventionally done. Once the atomized liquid agent is injected into the exhaust pipe 12, it may be used for emissions abatement.
In this exemplary embodiment, the emission abatement device 16 may include an oxidation catalyst 26 and a filter 28. In one exemplary embodiment the filter 28 may be a soot particulate filter. Hydrocarbon fuel may be used as the liquid agent which is atomized and aided in advancement by the flow of exhaust gases downstream to the oxidation catalyst 26. The catalyst 26 will catalyze an exothermic reaction between oxygen present in the exhaust gases and atomized air with the injected fuel. The catalyst 26 includes catalytic material disposed on a substrate. The catalytic material may be a precious metal, such as platinum or palladium, for example. The highly exothermic reaction produces heat that is transferred to the downstream-positioned particulate filter 28.
The particulate filter 28 of the emission abatement device 16 may be configured to trap soot particles present in the exhaust gases. From time-to-time, the filter 28 needs to be regenerated when becoming full of soot. The heat generated through the exothermic reaction may be used to raise the temperature of the soot particles trapped in the filter 28 to a temperature sufficient to ignite the particles thereby regenerating the particulate filter 28. It should be appreciated that the particulate filter 28 may be coated with catalytic material thereby eliminating the need for the oxidation catalyst 26.
In an alternative exemplary embodiment, the emissions abatement device 16 may include a selective catalytic reduction catalyst, which reduces the oxides of nitrogen present in exhaust gases. Urea may be used as the liquid agent in supply 18 to reduce the oxides of nitrogen at appropriate times.
The body 38 includes a number of air channels 42 radially disposed therein. The air channels 42 extend through the body 38 allowing the opening 40 to be in fluid communication with the area surrounding the outer surface 43 of the body 38. An atomizing nozzle 44 is disposed at an end 46 of each air channel 42 proximate to the opening 40.
The configuration shown in
When the atomizer 14 is disposed in the exhaust pipe 12, exhaust gases flow through the opening 40 thereby carrying the atomized liquid agent downstream to other portions of an exhaust system 10, such as an emission abatement device 16. The shearing of the liquid agent with the pressurized air at a position proximate to the atomizing nozzles 44 allows smaller particles to be to be advanced through the atomizing nozzle 44. It should be appreciated that the atomizer 14 shown in
It should be further appreciated that the atomizer 14 can be dimensioned to meet particular configurations. For example, the cylindrically-shaped atomizer shown in
There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of apparatus, systems, and methods that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present disclosure.
