CN101232934A - Coated screen adsorption unit for controlling evaporative hydrocarbon emissions - Google Patents
Coated screen adsorption unit for controlling evaporative hydrocarbon emissions Download PDFInfo
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- CN101232934A CN101232934A CNA2006800282069A CN200680028206A CN101232934A CN 101232934 A CN101232934 A CN 101232934A CN A2006800282069 A CNA2006800282069 A CN A2006800282069A CN 200680028206 A CN200680028206 A CN 200680028206A CN 101232934 A CN101232934 A CN 101232934A
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Abstract
A hydrocarbon adsorption unit for recovery of volatile hydrocarbons which emanate from several sources and which would otherwise be released into the atmosphere through the air cleaner of an automobile engine when the engine is shut off. The unit is positioned in the air intake system such that all air flowing through the engine passes through the unit. The unit comprises a housing having an air inlet and an air outlet. The housing contains a substrate and a volatile hydrocarbon adsorber material coated on the surface of the substrate. The adsorber material may be silica gel, a molecular sieve and/or activated carbon. The material further contains a binder that will cause the material to adhere to the surface of the substrate.
Description
The cross reference of related application
The name that the application requires on June 1st, 2005 to submit to is called the priority of the U.S. Provisional Patent Application No.60/686486 of " COATED SCREENADSORPTION UNIT FOR CONTROLLING EVAPORATIVEHYDROCARBON EMISSIONS ".
Technical field
The present invention relates to a kind of device that is used for the volatile hydrocarbon fuel vapo(u)r of adsorption vehicle gas handling system.These steams produce behind tail-off, if do not adsorb, then can flow out air purifier and enter atmosphere.
Background technology
The system and method that is used to capture from the volatile hydrocarbon fuel vapo(u)r of fuel tanks of automobile is known.This system is commonly referred to as the evaporation loss control system based on the protection filter (canister) that comprises regenerable sorbent (for example active carbon).Adsorbents adsorb volatile hydrocarbon, and when engine operating condition is fit to hydrocarbon that burning is captured, adsorbent is crossed in circulation of air so that its desorb, and the air stream that will be rich in hydrocarbon is then sent in the engine, at the hydrocarbon of this burning desorb.Evaporation loss control system: US 4877001, US 4750465 and US 4308841 are disclosed in the following United States Patent (USP).
The system and method that is used for the unburned hydrocarbon of adsorption vehicle waste gas stream also is known.The unburned hydrocarbon that these system and methods discharge when being specially adapted to the adsorption vehicle engine cold-start.
For example, US 4985210 relates to a kind of purification device for automobile exhaust gas, and this device uses three-way catalyst, uses y-type zeolite or modenite in the hydrocarbon trap of this three-way catalyst upstream.In the embodiment shown in Figure 2 of US4985210, active carbon bed is set in the adsorbent zone upstream.According to the temperature of waste gas stream, the Electromagnetic Control valve system rises with the waste gas conductance in active carbon bed or on every side, then the effect by adsorbent zone and three-way catalyst.
US 5051244 relates to a kind of method of handling engine efflux, wherein in the cold start-up stage of power operation air-flow is led by the molecular sieve of adsorbent zone.When hydrocarbon begins desorb, air-flow walk around adsorbent zone up to catalyst under its operating temperature, at this moment make air flow stream cross adsorbent zone again, with the desorb hydrocarbon and bring it into catalyst zone.The paper of M.Heimrich, L.Smith and J.Kotowski " Cold-Start Hydrocarbon Collection for Advanced Exhaust EmissionControl " (SAE publication number 920847) discloses a kind of device, and its function class is similar to the device among the US 5051244.
US 5125231 discloses a kind of engine exhaust system that is used to reduce hydrocarbon emissions, comprises using beta-zeolite as hydrocarbon adsorbent.Silica/alumina is preferred adsorbent than the zeolite that is 70/1～200/1.This device comprises by-pass line and valve, be used for when cold start waste gas is directly introduced second converter from first converter, and when first converter reaches firing temperature or walk around second converter or the effluent of second converter is circulated to first converter.
US 5158753 discloses a kind of waste gas purification apparatus, comprising: catalyst-assembly, and it is installed in the explosive motor exhaust passageway, is used to handle engine exhaust; Adsorbent equipment, it is installed in the exhaust passageway between catalyst-assembly and the internal combustion engine, is used to handle engine exhaust.A kind of embodiment comprises heat exchanger, is used at the waste gas that flows to adsorbent equipment from internal combustion engine and flows to from adsorbent equipment between the waste gas of catalyst-assembly carrying out heat exchange.Perhaps, catalyst-assembly comprises the catalyst in the low temperature side gas channel that is fixed on heat exchanger, and allows to flow to from the waste gas that internal combustion engine flows to adsorbent equipment the high temperature side gas channel of heat exchanger.
US 6171556 discloses the method and apparatus of the waste gas stream of a kind of pack processing hydrocarbonaceous and other pollutant.This method may further comprise the steps: make waste gas stream flow through catalysis member comprising the integral body with first catalyst zone and second catalyst zone, thereby contact with the catalyst of first catalyst zone, so that at least a portion pollutant in the waste gas stream is converted into harmless product.Then waste gas stream is discharged from the catalysis member, and make it flow through adsorbent zone, to adsorb at least a portion hydrocarbon pollutant with adsorbent composition.Waste gas stream is discharged from adsorbent zone, and make it flow to second catalyst zone, so that at least a portion pollutant is converted into harmless product.The waste gas stream that to so handle by suitable discharging approach enters atmosphere then.Preferred adsorbent is the higher and low zeolite of relative Bronsted acidity of ratio of silica/alumina.Adsorbent composition preferably comprises beta-zeolite.
The system that is used for absorption steam (otherwise this steam will be discharged into the atmosphere from the gas handling system of vehicle) when vehicle cuts out also is known.U.S. Patent Application Publication No.US2002/0043156 A1 discloses a kind of housing that air flows to the air cleaner of mouth and air outflow port that fixedly has.This air cleaner comprises the filter medium that is arranged on the carrier, and this carrier is arranged in the housing or is fixed on the housing, and the hydrocarbon sorbing material of air permeable is set between the air outflow port end filter medium of filter and carrier.Preferred hydrocarbon adsorbent is the active carbon filter cloth.
EP 1110593 A1 are similar to above-mentioned U.S. Patent Application Publication.This european patent application discloses a kind of air cleaner assembly, comprises housing and is arranged on the interior a plurality of filter courses of housing.One of them filter course is the polyurethane foam that is soaked with carbon, is used for removing when tail-off the hydrocarbon vapour that diffuses to filter by air intlet.
Find, behind tail-off, in the gas handling system of automobile engine, assembled a large amount of volatile hydrocarbons from several sources.Behind the tail-off, these hydrocarbon then are discharged in the atmosphere.Existing systems and method are less to preventing the concern of this hydrocarbon emissions by engine aspirating system, if reason is and compares from the hydrocarbon emissions of fuel system and waste gas stream unprocessed then that can enter atmosphere, the amount of this emission is less.Yet, consider that federal government and each state about all unburned hydrocarbon emissions in the atmosphere being eliminated the decree of the increasingly stringent of technical feasibility, need be provided for adsorbing the device of this hydrocarbon.
Therefore, the purpose of this invention is to provide a kind of device of volatile hydrocarbon of the gas handling system discharging that is used for being adsorbed on shutdown event engine upstream, thereby prevent that this hydrocarbon is discharged in the atmosphere.
Summary of the invention
The present invention includes a kind of new device, be used for being adsorbed on shutdown event and be discharged into hydrocarbon in the vehicle motor gas handling system.One aspect of the present invention relates to the evaporative hydrocarbon emissions that the porous substrate that uses hydrocarbon adsorbent to apply is controlled vehicle.Especially, the porous substrate that the present invention relates to use new adsorbent to apply is controlled when engine stoping operation the evaporative hydrocarbon emissions from the gas handling system of motor vehicle.
Another aspect of the present invention relates to base material that hydrocarbon adsorbent applies and at least one protection filter screen adjacent with described hydrocarbon adsorbent coated substrate, is used to control when engine stoping operation the evaporative hydrocarbon emissions from the gas handling system of motor vehicle.
Illustrate other purpose of the present invention and advantage by the following description and the appended claims.
Description of drawings
Fig. 1 is the exploded view according to air purifier of the present invention.
Fig. 2 is section (square structure the is shown down) perspective view of hydrocarbon adsorbent equipment of the present invention;
Fig. 3 is the sectional view of hydrocarbon adsorbent equipment of the present invention along the line 3-3 among Fig. 2.
The specific embodiment
Volatile hydrocarbon adsorbent equipment of the present invention is particularly suitable for adsorb volatile hydrocarbon fuel steam, and this steam is not discharged into the gas handling system from automobile engine the atmosphere if be not adsorbed when tail-off.This fuel vapo(u)r is from several sources, for example residual fuel, clay (puddle), running back injector leakage, seepage, from the hydrocarbon of waste gas circulation, from the petroleum hydrocarbon of PCV etc.Target of the present invention is these fuel vapo(u)rs of absorption, will be by the LEV II of California Air Resource Board rigid and absolute enforcement and PZEV restriction and will be by the Tier II restriction (at vehicle in 2004) of federal government's rigid and absolute enforcement to help to satisfy.
In one embodiment, volatile hydrocarbon adsorbent equipment of the present invention is arranged in gas handling system, passes through this device so that flow through all air of engine.In another embodiment, the volatile hydrocarbon adsorbent equipment can be positioned at air by beyond the direct runner of gas handling system, and for example the volatile hydrocarbon adsorbent equipment can be located on the one or more walls that lean against gas handling system.Gas handling system comprises the housing with air intlet and air outlet slit.Comprise one or more volatile hydrocarbon adsorbent equipments in the housing, this adsorbent equipment comprises base material and is coated in the volatile hydrocarbon sorbent material of substrate surface.Base material can comprise adhesive, this adhesive with the hydrocarbon adsorbent material adhesion to substrate surface.
Volatile hydrocarbon adsorbent equipment of the present invention comprises the framework that holds porous substrate and be coated in the volatile hydrocarbon sorbing material of substrate surface.This porous substrate can be made by any material known in the art, can be metal or polymer.Preferred metals is drawn together stainless steel alloy (for example 304 and 316 stainless steels), Fe-Cr-Al alloy, titanium or aluminium.Preferred polymeric substrate comprises nylon, polypropylene, PVC, ABS or polyethylene.Porous substrate must be able to tolerate the environment in the automotive hood.Therefore, metal base is preferred, and nylon than other polymeric substrate more preferably.
In one embodiment, porous substrate is the filter screen with big opening that applies with the volatile hydrocarbon sorbent material.This filter screen can be the weaving or nonwoven, preferably textile.The weaving filter screen provides the opening that can obtain even air stream and can not form raceway groove.This filter screen can weld or not weld at the twine joint.Must consider the selection of filter screen geometry.Usually, filter screen is a silk screen, and its weavy grain is fine and close and have little opening, to increase the probability that hydrocarbon molecule and coated mesh wire connection are touched when hydrocarbon diffuses through filter screen.Yet, also wish to have enough big opening, the air flow restriction with engine running the time is reduced to minimum.Therefore, for example mesh wire diameter can be about 0.01～about 0.07 inch, preferred about 0.02～0.035 inch, more preferably from about 0.023～0.028 inch, size of mesh opening is about 4 * 4～about 100 * 100 twines of every linear inch, about 8 * 8～about 20 * 20 twines of preferred every linear inch, about 12 * 12 twines of more preferably every linear inch.
In one embodiment, the hydrocarbon adsorbent equipment also comprises at least one protection filter screen or filter cloth of the base material adjacent that applies with hydrocarbon adsorbent.This protection filter screen can be positioned at the upstream side or the downstream of hydrocarbon adsorbent coated substrate.In another embodiment, the hydrocarbon adsorbent equipment is included in the first protection filter screen of described hydrocarbon adsorbent coated substrate upstream side and protects filter screen in second of described hydrocarbon adsorbent coated substrate downstream.This protection filter screen or filter cloth can be metals weaving or nonwoven, or plastics, for example nylon, polypropylene, polyester, PVC, ABS or polyethylene.In a kind of preferred implementation, can use the woven nylon filter screen.One of function of this filter screen is to prevent the adsorbent coating just in case lose from entering engine after filter screen comes off.Under the environment of automobile engine, the adsorbent disbonding may become problem.For example, sorbent material can because from the heat of engine and vibration and may be broken, peel off (peal), cracking or come off from porous substrate, enter engine, and block tiny engine passage, for example fuel injects pipeline.Therefore, the protection filter screen must have the opening that is small enough to hold back the adsorbent coating granule, but simultaneously opening must be enough be subjected to excessive restriction so that the air during engine running is mobile greatly.The opening of protection filter screen can be about 50～about 1000 microns, and preferred about 200～about 500 microns, mesh wire diameter is about 30～about 1000 microns, preferred about 80～about 200 microns.
In another embodiment, described coating porous substrate and described at least one protection filter screen or filter cloth and frame fixation are in the same place.The framework of particularly suitable is the nylon framework of about 1/16 inch and width about 1/2 of thickness.Can be by any means known in the art, the heat bonding of for example mechanical approach, welding, chemical adhesion or polymer frame is fixed together this frame assembly.
Can be more readily understood volatile hydrocarbon adsorbent equipment of the present invention with reference to accompanying drawing, these accompanying drawings only are exemplary, are not intended to limit the present invention or its application or purposes.Specifically referring to Fig. 1, air purifier 2 is formed by two-piece housing 4,6, and this housing defines the air purifier 2 of long and flat.This housing defines the inside or the shell 8 of sealing hollow, and wherein first parts 4 have the clean air port one 0 that is used to connect clean air pipeline 12.Second parts 6 have the import (not shown) that is used to connect non-clean air pipeline that is positioned at these second parts, 6 one sides.With this two-piece housing assembling, constitute the single-piece air purifier 2 that is installed in motor vehicle hood below.
Preferably, two-piece housing 4,6 is made of plastics, and described two parts snap together, and forms single-piece air purifier 2.Perhaps, housing can be made by metal or plastic-metal composite material.The air purifier 2 that shows in the accompanying drawings and describe is rectangle, but is to be understood that air purifier 2 can have different shapes, and is for example circular or oval.
Air purifier 2 comprises air filting material 14.Air filting material 14 is arranged in the hollow inside 8 of two-piece housing 4,6.The effect of air filting material 14 is the fouls that exist in the absorbing environmental air, and housing is divided into non-clean air parts 16 that are positioned at air filting material 14 upstreams and the clean air part 18 that is positioned at air filting material 14 downstreams.Usually, air filting material 14 is made by the paper that the compression fabric forms.For air is passed through, air filting material 14 has small hole.When sucking air from environment, air filting material 14 is collected foul and dust granule.Perhaps, air filting material 14 can have the oil based material of adding or be formed by oil based material, so that dust adhesion is on air filting material 14.The clean air that leaves air filting material 14 shown in the arrow 20 does not contain foul and dust granule substantially.
When engine start, from environment, suck air, filter through air filting material 14, clean air 20 is delivered to engine more then.Yet when tail-off, unburned hydrocarbon may be discharged in the environment.Therefore, enter environment in order to prevent hydrocarbon, air purifier 2 is provided with hydrocarbon adsorbent equipment 21.
As shown in Figure 1, hydrocarbon adsorbent equipment 21 is arranged in the downstream of clean air part 18 air filting materials 14 of housing 4,6.In another embodiment, hydrocarbon adsorbent equipment 21 can be arranged in the upstream (not shown) of non-clean air part 16 air filting materials 14 of housing 4,6.Illustrate as Fig. 1 is clear, the shape of hydrocarbon adsorbent equipment 21 is identical with first parts 4 of housing.Preferably, hydrocarbon adsorbent equipment 21 comprises the base material 22 that hydrocarbon adsorbent applies, and base material 22 is clipped between upstream protection filter screen 24 and the downstream protection filter screen 26.In another embodiment, there is not upstream filter screen 24, but importantly uses downstream filter screen 26 to prevent that any adsorbent coating granule from entering engine.Hydrocarbon adsorbent equipment 21 can be connected with first parts 4 by any approach known in the art, for example by embedding moulding or permanent snapping, can not come off from housing easily so that install 21.Therefore, when the engine (not shown) turns round, leave the clean air 20 of air filting material 14 and will protect filter screen 24, hydrocarbon adsorbent coated substrate 22 and downstream protection filter screen 26, arrive clean air pipeline 12 by the upstream.
In a preferred embodiment, hydrocarbon adsorbent coated substrate 22 can be from regeneration.They are saturated opposite up to hydrocarbon adsorbent coated substrate 22 with absorbing hydrocarbon and capture, and hydrocarbon can relatively easily discharge from hydrocarbon adsorbent coated substrate 22.When this release occurs in medium engine speed and advances clean air pipeline 12 to running at a high speed and with air.Preferably, when air passed through air purifier 2, the hydrocarbon that captures in the hydrocarbon adsorbent coated substrate 22 was drawn out and is delivered to engine by clean air pipeline 12, burns in engine.By allowing hydrocarbon to discharge from hydrocarbon adsorbent equipment 21, preferred implementation of the present invention has realized regeneration certainly, and the result that handles of hydrocarbon is that whole life period at vehicle need not to change hydrocarbon adsorbent equipment 21.
Air purifier 2 with hydrocarbon adsorbent equipment 21 can be made by two-piece housing 4,6 is provided.By applying, obtain hydrocarbon adsorbent equipment 21 with hydrocarbon sorbing material 28.Follow following assembling air purifier 2: air filting material 14 is inserted enclosure interior, then hydrocarbon adsorbent coated substrate 22 is connected to (comprising upstream protection filter screen 24 and downstream protection filter screen 26) first parts 4 of housing.
Referring to Fig. 2, hydrocarbon adsorbent equipment 30 comprises hydrocarbon adsorbent coated substrate 32 especially, and base material 32 comprises upstream protection filter screen (or filter cloth) 34 and downstream protection filter screen (or filter cloth) 36.Hydrocarbon adsorbent applies filter screen and is formed by aforesaid porous substrate.Hydrocarbon adsorbent applies filter screen 32 and protects filter screen or filter cloth 34,36 and framework 38 to be fixed together.Fig. 3 shows the sectional view of hydrocarbon adsorbent equipment 30, and hydrocarbon adsorbent equipment 30 comprises hydrocarbon coated substrate 32, and it comprises upstream protection filter screen (or filter cloth) 34 and downstream protection filter screen (or filter cloth) 36, and is fixed together with framework 38.
Above-mentioned showing the invention provides a kind of hydrocarbon adsorbent equipment, and this device can be the part of parts in the gas handling system.The present invention also can be by making it become the hydrocarbon adsorbent equipment with any existing parts in the hydrocarbon sorbing material coating gas handling system.This makes the number of components in the gas handling system obviously reduce.Although the hydrocarbon sorbing material in the gas handling system of motor vehicle has been carried out specific emphasizing, be to be understood that the present invention can be used for the gas extraction system of motor vehicle.
When engine is in operation mode,, make clean air flow pass through this device so that the volatile hydrocarbon desorb of being adsorbed by material, the hydrocarbon of the desorb of burning then promptly when vehicle movement and/or when being in idle mode.The absorption of the volatile hydrocarbon in apparatus of the present invention occurs in lower temperature, for example about 0～350 (higher temperature often helps desorb rather than absorption).
The housing of air purifier can be made of various metals or polymer.Certainly, selected metal or polymer should tolerate the temperature in the gas handling system under the various engine running conditions (particularly idle running) for a long time, and preferably have light weight.Certainly, this housing must tolerate the oil that is usually used in engine running, fuel, lubricating grease etc.The size of housing is not crucial, but be subject to the size of the pipeline from the air purifier to the motor intake manifold, reason is that housing should fit closely in this pipeline (can use common oil resistant and the liner of anti-the hydrocarbon in shell end, thereby guarantee between hull outside and the inner-walls of duct hermetic closed).
Housing has air intlet and air outlet slit, and usually at its both ends open.Hull shape is not crucial, promptly can be cylindrical, triangle, square, rectangle, polygon etc.Shell length is not crucial yet, but shell length is generally about 5～about 12 inches, and width or diameter are about 5～about 12 inches, and wall thickness is about 0.25 inch.
The suitable material of making housing comprises thermoplastic polymer, thermosetting polymer and metal, particularly aluminium, Fe-Cr alloy or the Cr-Al-Fe alloy that the temperature that exists in the engine room and material (for example liquid fuel, fuel vapo(u)r, oil, lubricating grease etc.) are had tolerance.
Be used to implement sorbing material of the present invention and comprise the hydrocarbon adsorbent material that is coated on the base material.Hydrocarbon adsorbent preferably has hydrophobicity and close organic property (promptly organic chemicals being had the height adsorptivity).Preferably, base material comprises the polymer or the metal of forms such as plate, net, paper tinsel, for example aluminium, titanium, stainless steel, Fe-Cr alloy or Cr-Al-Fe alloy.In order to increase the surface area of adsorbent, wish that metal base exists in the ripple mode.Usually, the heap(ed) capacity of the hydrocarbon adsorbent on the base material is about 0.05～about 1g/in
2, 0.1～about 0.4g/in more preferably from about
2, 0.2g/in for example
2
Hydrocarbon adsorbent can be silica gel, molecular sieve, active carbon or its mixture.This material can be used as the individual layer of silica gel, molecular sieve or active carbon or each independently multilayer be arranged on the base material.Preferably, this material only comprises molecular sieve, perhaps comprises the mixture of the active carbon (hole dimension is about 5～about 500 dusts) of molecular sieve and about 5～about 50wt%.
Preferably, molecular sieve is natural or synthetic zeolite, for example faujasite, chabasie, clinoptilolite, modenite, silicalite, X zeolite, zeolite Y, overstable zeolite Y, ZSM zeolite, offretite or beta-zeolite.
May need base material is carried out preliminary treatment, to help prevent the hydrocarbon adsorbent disbonding.In one embodiment, can for example come pretreating substrates, thereby improve the adhesion between base material and the washcoated layer of hydrocarbon absorption (washcoat) by base material is applied priming coat.For example, can carry out preliminary treatment to base material and apply priming coat with metal oxide (for example aluminium oxide, cerium oxide or zirconia), metal spraying by electric arc layer, metal spraying by electric arc layer and metal oxide, sol solution (for example silicon dioxide gel, titanium oxide sol or alumina sol), perhaps base material be carried out acid etching.
Alternatively, at first can apply filter screen with the high surface component, described component constitutes metal pretreated thermic arc sprayed coating and washcoated alternatively layer, for example aluminium oxide, cerium oxide and zirconia.Metallic thermal arc sprayed layer can be used for improving the adhesiveness of washcoated layer.Usually, metallic thermal arc sprayed layer of the present invention can apply by hot-spraying technique, and hot-spraying technique comprises plasma spray coating, single line plasma spray coating, high-velocity oxy-fuel spraying, combustion wire (combustion wire) and/or powder spraying, electric arc spraying etc.
An aspect of of the present present invention, electric arc spraying on base material (for example twin wire arc spray) metal (as here with claim in used, this term comprises metal mixture, includes but not limited to the combination of metal alloy, pseudo-alloy and other intermetallic) structure that obtains unexpectedly is especially suitable for use as the base material (for example refractory metal oxide) of washcoated layer.Twin wire arc spray (here by term " line electric arc spraying " and more the term of broad sense " electric arc spraying " contain) be known technology, for example, by reference it is incorporated into this referring to US 4027367.In brief, in twin wire arc spray technology, two raw material threads serve as two consutrodes.These silks are insulated from each other when delivering to spray tip (to be similar to the mode of delivering to wire flame spray gun).Join in the air-flow center that these produce in nozzle.Electric arc causes between this silk, and the electric current that flows through silk makes the fusing of its end.Compression atomizing gas (being generally air) guiding by nozzle and arc region, is sheared molten melt drop, shift spraying on the base material onto with formation.Have only the wire raw material to can be used for arc spraying system, reason is that raw material must be a conduction.The high-temperature particle that spray gun produced with metal base on point of impingement place form small weld zone.Therefore, this electric arc spraying layer (is sometimes referred to as in this article that " anchoring layer ") has good cohesive strength and the adhesion splendid to base material.
According to the present invention, the raw material that can utilize (but being not limited to) following metal and metal mixture is deposited on the thermic arc sprayed coating of various compositions on the base material: Ni, Al, Ni/Al, Ni/Cr, Ni/Cr/Al/Y, Co/Cr, Co/Cr/Al/Y, Co/Ni/Cr/Al/Y, Fe/Al, Fe/Cr, Fe/Cr/Al, Fe/Cr/Al/Y, Fe/Ni/Al, Fe/Ni/Cr, 300 and 400 series stainless steels, and optional above-mentioned one or more mixture.In one embodiment, metallic thermal arc sprayed layer can comprise nickel and aluminium.In metallic thermal arc sprayed layer, aluminium can account for the about 3～10% of nickel and aluminium gross weight, accounts for about 6～8% alternatively.
In another embodiment, the base material of available high surface refractory metal oxide coated substrate or thermic arc spraying, drying is about 0.5～about 2 hours under about 90～about 120 ℃, calcines 0.5～about 2 hours down at about 450～about 650 ℃ then.The high surface refractory metal oxide is that prior art is known.Usually, the specific area of this refractory metal oxide is about 60～about 300m
2/ g.Available refractory metal oxide comprises one or more the mixture in aluminium oxide, titanium oxide, zirconia and aluminium oxide and titanium oxide, zirconia, cerium oxide, barium monoxide and the silicate.Preferably, refractory metal oxide comprises gama-alumina.
Then, apply base material and dry (for example, under about 105 ℃) that apply through refractory metal oxide with required sorbent slurry.Perhaps, can use the slurry of silica gel, molecular sieve and/or active carbon to apply the base material that applies through refractory metal oxide respectively, forming multilayer, and carry out drying as mentioned above applying each interlayer.
If desired, after applying each layer, can on adsorbent, apply the top coat of another high surface refractory metal oxide, carry out drying subsequently as mentioned above.
Be to be further noted that not being every layer all needs to extend on the whole layer of base material.For example, available gama-alumina applies the base material of whole length, dry then and calcining.Apply the base material that scribbles aluminium oxide and the drying of whole length then with selected zeolite and adhesive.Then, can be only the zeolite and the adhesive phase of a part be applied active carbon layer, dry then.Perhaps, the front portion through the alumina coated base material is applied selected zeolite and adhesive, simultaneously its rear portion is applied active carbon and adhesive, dry then.As alternative dispensing means, comprise that the alumina coated base material in selected zeolite intermediate layer can then apply the mixture of gama-alumina and active carbon (aluminium oxide of 20-80wt%, all the other are active carbon), dry then.
Preferred sorbent material is the zeolite with high silicon dioxide/aluminium oxide ratio.Particularly preferred adsorbent comprises disclosed zeolite beta among the US 6171556, by reference the document is incorporated into this in full.
Usually, the sieve material with so-called three-D pore structure is preferable over the sieve material with one dimension or two-dimentional pore structure, although some also can be accepted among the latter.Acceptable material has the micro-pore diameter of about 3-8 dust usually.Unexpectedly, the ratio scope of silica/alumina is that about 25/1～300/1, preferred about zeolite of 100/1～about 250/1 (particularly beta-zeolite) has been proved to be special effective adsorbent.Preferred beta-zeolite is the ion-exchange beta-zeolite, for example H/ beta-zeolite and Fe/ beta-zeolite.
Preferred zeolite comprises ZSM-5, Y zeolite and beta-zeolite, and wherein beta-zeolite is particularly preferred.Can handle preferred zeolite to reduce sour number of sites.This can be by realizing with organic acid or inorganic acid leaching zeolite.Preferred acid comprises strong inorganic acid, for example sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid etc.; Carboxylic acid, for example trifluoroacetic acid; Dicarboxylic acids, for example ethanedioic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, phthalic acid etc.Available acid preferably includes polyacid, preferred two functional acid, more preferably dicarboxylic acids, wherein ethanedioic acid most preferably.The concentration of used acid is 0.02～12N, preferred 0.1～10N, and solid zeolite concentration is 0.01～1.0g/ml, preferred 0.05～0.5g/ml.Leaching is carried out in suitable temperature range, is generally 10～100 ℃, for example, when using sulfuric acid preferred 70～100 ℃, when using ethanedioic acid preferred 10～50 ℃.Leaching is carried out the sufficiently long time, and to reach obtainable expectation silica/alumina ratio under leaching condition and concentration, leaching time is generally about 0.5～5 hour, preferred 0.5～3 hour.
Zeolite can directly use, or can handle with steam under about 350～about 900 ℃.Preferably, steam treatment is at 400～800 ℃, more preferably 500～750 ℃, most preferably carries out under 550～750 ℃.Vapor (steam) temperature can be with for example per hour 100～600 ℃ appropriate speed rising.Vapour concentration is generally 10～100%, preferred 30-100%, and wherein preferred concentration is about 50-100%, all the other are air.Steam treatment is preferably under atmospheric pressure carried out.The duration of steam treatment will be enough to handle zeolite, is generally 0.5～48 hour, and preferred 0.5～24 hour, more preferably 0.5～8 hour, most preferably 0.5～5 hour.Steam treatment does not significantly improve the silica/alumina ratio.Yet, it is believed that steam treatment passes through to remove the acidity that part aluminium at least reduces zeolite from zeolitic frameworks.Find,, and stop coke to form through the durability of zeolite raising zeolite when being used for the hydrocarbon of adsorptive gaseous stream of steam treatment.Preferably, zeolite is both carried out acid (for example sulfuric acid) leaching and also carried out steam treatment.
In a kind of particularly preferred technology, zeolite is at first carried out acidleach get and carry out steam treatment then.Alternatively, steam treatment and the acidleach step of getting can repeat with any required order.For example, the zeolite through leaching and steam treatment can repeat leaching, steam treatment then.In a kind of specific embodiment, can leach zeolite, steam treatment and then leach.
Disclose a kind of process useful of handling beta-zeolite among the CN 1059701A that on March 25th, 1992 announced, by reference the document has been incorporated into this.The document discloses the beta-zeolite of a kind of high Si, and this zeolite prepares by organic-beta-zeolite that the amine form technology is made being calcined to remove nitrogen compound.Under 10～100 ℃, with organic acid or inorganic acid solution beta-zeolite is leached, wherein acid solutions is 0.02～12N, preferred 0.1～10N, and solid zeolite concentration is 0.01～1.0g/ml, preferred 0.05～0.5g/ml, and leaching time is 0.5～5 hour, preferred 1～3 hour.After the leaching, under 400～900 ℃, per hour rise to 600 ℃ zeolite carried out steam treatment from 100 ℃ with vapor (steam) temperature.
A preferred embodiment of the invention, operable zeolite are except steam treatment, also through handling to improve the ratio of silica/alumina.The method that improves the silica/alumina ratio causes aluminium oxide to be removed from zeolite.For example, leaching is removed aluminium from zeolite framework.Removed aluminium is removed by leaching liquid with the aluminium ion salt form.
About the present invention, it should be noted that the acidity that the aluminium oxide in the zeolitic frameworks is given especially.It is believed that the high silicon dioxide/aluminium oxide that obtains by leaching is than relevant with the acidity of zeolite.The acidity of zeolite is considered to influence the durability of zeolite when being used for from waste gas stream adsorbed hydrocarbons, and described waste gas stream for example is that automobile exhaust gas stream and industrial waste gas flow, and its temperature typically is 300～800 ℃, more typically is 350～600 ℃.When using in this environment, zeolite often loses adsorption efficiency, and this mainly is because hole plug and/or zeolitic frameworks collapse diffusing.Can keep stable zeolitic frameworks by the condition of control zeolite treatment.These conditions comprise acid concentration, vapor (steam) temperature etc.Relatively mild condition has reduced the trend that zeolitic frameworks worsens in processing procedure, and can make skeleton stabilisation on the position of removing aluminium oxide.
It is believed that in addition steam treatment is removed aluminium from zeolitic frameworks.Affected aluminium still rests in the zeolite, may stay in the hole.Zeolitic frameworks is considered to stabilisation under the situation that does not contain aluminium, and the aluminium ion in the hole forms aluminium oxide.Remaining aluminium oxide is considered to the not contribution of zeolite acidity to reducing in the hole.Aluminium oxide in the hole can remain in the hole, is perhaps washed out or leaches in follow-up leaching step.
Find to have the anti-coking of improvement without steam treatment or through this zeolite of steam treatment, the coke that has promptly obviously reduced in the Engine Block Test process forms.Can reduce acidity although become known for improving the acidleach access method of the silica/alumina ratio of zeolite, such method is considered to remove the aluminium atom from zeolite granular indiscriminately.For example steam treatment process is preferentially removed aluminium in Bronsted acid site from zeolitic frameworks.By more effectively stoping coking and, can recognizing its importance about how handling zeolite to obtain this performance and to make skeleton worsen minimum knowledge.Zeolite is leached collapsing looses just can cause Bronsted acidity to reduce in fact; But use for example steam treatment process separately, or more preferably replenish leaching again, obtain being suitable for the more durable zeolite of doing according to hydrocarbon adsorbent of the present invention.
The hydrocarbon adsorbent material also can comprise the adhesive that causes this material and substrate surface to adhere to.This adhesive is also referred to as washcoated layer adhesive.The washcoated layer adhesive that the typical case is used to prepare slurry includes but not limited to: organic polymer; Aluminium oxide, silica or zirconic colloidal sol; Aluminium oxide, silica or zirconic inorganic salts, organic salt and/or hydrolysate; Aluminium oxide, silica or zirconic hydroxide; Hydrolyzable is the organosilicate of silica; And composition thereof.
Preferred adhesive is an organic polymer, and its consumption is 0.5～20wt% based on described material weight, preferred 2～10wt%.Organic polymer can be thermosetting or thermoplastic polymer, and can have plasticity or elasticity.Polymer adhesive can comprise known suitable stabilizers of polymer arts and age resister.Thermoset elastomeric polymeric thing most preferably, with it as latex, preferably introduce adsorbent composition as water paste.Applying said composition and when dry, adhesive material is fixed to one another and fix with substrate surface with the hydrocarbon adsorbent particle, and in some cases, adhesive material can be cross-linked to each other and adhere to improve.This has strengthened the globality of coating, to the adhesion of base material, and provides structural stability when motor vehicle runs into vibration.The use of adhesive makes material to adhere to base material, and need not priming coat.Adhesive also can comprise additive, to improve water proofing property and adhesion.
Available organic polymer binder composition comprises polyethylene, polypropylene, polyolefin copolymer, polyisoprene, polybutadiene, polybutadiene copolymer, chlorinated rubber, nitrile rubber, polychlorobutadiene, ethylene-propylene-diene elastomer, polystyrene, polyacrylate, polymethacrylates, polyacrylonitrile, poly-(vinyl esters), poly-(vinyl halide), polyamide, cellulosic polymer, polyimides, acrylic resin, vinylacrylic acid resinoid and styrene-acrylonitrile copolymer acid resin, polyvinyl alcohol, thermoplastic polyester, thermosetting polyester, polyphenylene oxide, polyphenylene sulfide, fluorinated polymer is as poly-(tetrafluoroethene) polyvinylidene fluoride, polyvinyl fluoride, and chlorine/fluo-copolymer such as ethylene-chlorotrifluoro-ethylene copolymer, polyamide, phenolic resins and epoxy resin, polyurethane, acrylic acid/styrene acrylic copolymer latex and silicone polymer.Particularly preferred polymer adhesive is acrylic acid/styrene acrylic copolymer latex,
Find that the component compatibility of slurry that comprises sorbent material and polymer adhesive (for example latex emulsion) is important for keeping stability of slurry and uniformity.In the present invention, compatibility is meant that adhesive and sorbent material remain the mixture of individual particles in slurry.It is believed that working as polymer adhesive is latex emulsion, and this emulsion and hydrocarbon adsorbent material have when causing the two electric charge that repels mutually, emulsion and hydrocarbon adsorbent material are compatible, and slurry is stable, wherein hydrocarbon adsorbent material and polymer emulsion are evenly distributed in liquid medium (for example aqueous fluid, as water).If sorbent material and latex emulsion particle are not mutually exclusive, irreversible emulsion condensation then takes place on sorbent material.Therefore, these materials are inconsistent, and latex can coagulate from emulsion.
Generate the zeolite of low pH value mixture for those in being dispersed in water the time, can obtain stable in addition by improving the pH value.This is very important, and reason is that organic latex adhesive agent emulsion commonly used in this area is electronegative, thereby its pH value is usually greater than 7.When high pH value adhesive agent emulsion and the merging of low pH value zeolite slurry, can produce unstability, this often causes slurry to condense.According to the acidity of sorbent material, the pH level of slurry can be controlled at about 4～about 10.Preferred pH value scope be about 5～about 8, more preferably from about 6～about 7.5.
In another embodiment, preferably dispersant and binder combination are used.Dispersant can be anionic, nonionic or cationic, and its consumption is generally about 0.1～about 10wt% based on sorbent material weight.Obviously, the concrete selection of dispersant is important.Suitable dispersant can comprise polyacrylate, alcoxylates, carboxylate, phosphate, sulphonic acid ester/salt, taurine ester/salt, sulfosuccinate/salt, stearate/salt, laurate/salt, amine, acid amides, imidazoline, neopelex, dioctyl sodium sulphosuccinate and composition thereof.In one embodiment, preferred dispersing agent is low-molecular-weight polyacrylic acid, and many protons that wherein should acid are substituted by sodium.In a kind of particularly preferred embodiment, found that low-molecular-weight, anionic type dispersant (for example neopelex and dioctyl sodium sulphosuccinate) can provide excellent zeolite to disperse and zeolite-adhesive stability.For example, (promptly with the SAL-beta-zeolite of high Si/Al ratio, beta-zeolite through sulfuric acid to leach) and under the situation of styrene acrylic latex adhesive agent emulsion preparation slurry, found that low-molecular-weight anionic dispersing agent can provide excellent zeolite to disperse and zeolite-adhesive stability.Preferred composite comprises neopelex or the dioctyl sodium sulphosuccinate of the beta-zeolite of about 90wt%, about 9wt% acrylic polymer latex and about 1wt%.
Can provide enough stability for slurry mix although improve slurry pH value separately or add anionic dispersing agent, when not only improving the pH value but also using anionic dispersing agent, can obtain optimum.For example, produce the zeolite based slurry of low pH value in being dispersed in water and/or dispersant the time, can obtain stable in addition by improving the pH value as mentioned above.
Hydrocarbon adsorbent slurry of the present invention particularly comprises the slurry of polymer emulsion, can comprise conventional additives, for example thickener, antimicrobial, antioxidant etc.In one embodiment, can use thickener such as xanthans thickener or carboxymethyl cellulose thickener.The feasible coating (thereby obtaining enough hydrocarbon adsorption capacities) that can on the lower base material of surface area, obtain q.s of thickener.The secondary role of thickener can also be to utilize the sterically hindered raising slurry stability of discrete particles.And thickener also helps the adhesive coatings surface.
The method for optimizing that applies coating is to use spraying coating process.Can zeolite slurry (zeolite, water, adhesive, the thickener with appropriate viscosity) be sprayed on the filter screen by conventional route arbitrarily, for example use paint gun.Available dry air or nitrogen purge redundant sizing agent, thus dry coating and cleaning filter screen opening.Can repeat this technology, to obtain the adsorbent of desired amount.Then, under 25～200 ℃, preferred 90 ℃, in the mechanical convection baking oven that coated screen is fully dry.Other method that applies coating can comprise impregnation technology or following technology: from the roll filter screen of leaving behind, with it by the slurry pool in the continuous conveyor formula system.
Below non-limiting embodiment illustrated the present invention.Except as otherwise noted, all parts and percentage are all based on weight.
Embodiment
Embodiment 1
According to the beta-zeolite of the method preparation that proposes among the embodiment 5 of US 6171556 through sulfuric acid to leach (" SAL ").In the air atmosphere that is containing 60% steam under 650 ℃, the SAL beta-zeolite is carried out steam treatment 24 hours then, obtain SiO
2/ Al
2O
3Than the end product that is about 200.
500g is dispersed in the deionized water of 521g through the SAL of steam treatment end product, and the formation solids content is 48% slurry.Then this slurry is carried out ball milling, so that 90% particle has the particle size less than 9.5 microns.By in slurry, adding 21g colloidal state polyacrylic acid dispersant and 154g polyacrylic acid latex adhesive, obtain final slurry, its solids content is about that 50wt%, pH value are about 6, peak viscosity is 400cps.
Embodiment 2
Final slurry with embodiment 1 gained applies the wire gauze filter (mesh wire diameter is 0.028 inch, and every linear inch has 12 * 12 twines) that comprises the Cr-Al-Fe alloy.This coated screen is dry and place baking oven able to programme; Temperature slowly rises to 105 ℃ and kept 1 hour under this temperature.The dry weight of washcoated layer is 6.4g.Apply filter screen again with same procedure, the final dry weight of gained coating is 12.1g.
As the slurry of preparation as described in the embodiment 1 through the beta-zeolite of sulfuric acid to leach and polyacrylic acid latex adhesive, organic thickening agent, its solids content is about 50%, the pH value is about 6.This slurry is sprayed on the aluminium wire filter screen (size of mesh opening is per inch 12 * 12 twines, and mesh wire diameter is 0.023 inch).On the surface of 12 inches * 8.25 inches of filter screens, apply about 22g coating.Before the coated with aluminum filter screen, use silicon dioxide gel solution with its precoating and dry down at 70 ℃.Coated screen is assembled between the two-layer nylon wire (opening is about 300 microns) in the nylon framework.
Assembly is installed in the air purifier between air cleaner and engine of vehicle.This gas handling system that comprises zeolite coated screen assembly is carried out the standard hot dipping, carry out 48 hours the test of SHED round the clock (Sealed Housing for Evaporative Determination subsequently, sealed housing ofr evaporative emission determination), and with the SHED test comparison that the former gas handling system that does not have hydrocarbon adsorbent is carried out.Collect from the emission of gas handling system, and when EOT, analyze hydrocarbon content.The results are shown in table 1.
Table 1. is from the hydrocarbon total amount (in mg) of vehicle intake system discharging
| Vehicle 1 | Vehicle 2 | |||
| Hot dipping | 48 hours, round the clock | Hot dipping | 48 hours, round the clock | |
| The former gas handling system that does not have hydrocarbon adsorbent | ＜0.01 | 32.45 | 0.37 | 9.54 |
| Gas handling system with hydrocarbon absorption net-filter assembly | 0.01 | 5.60 | 0.03 | 1.89 |
Claims (13)
1. hydrocarbon adsorbent equipment that is used in the automotive air intake system, comprise porous substrate that hydrocarbon adsorbent applies and with at least one protection filter screen of described base material adjacent.
2. hydrocarbon adsorbent equipment as claimed in claim 1, wherein said hydrocarbon adsorbent are selected from silica gel, active carbon, faujasite, chabasie, clinoptilolite, modenite, silicalite, X zeolite, zeolite Y, overstable zeolite Y, ZSM zeolite, offretite and beta-zeolite.
3. hydrocarbon adsorbent equipment as claimed in claim 1, wherein said hydrocarbon adsorbent are beta-zeolite.
4. hydrocarbon adsorbent equipment as claimed in claim 1, wherein said porous substrate are wire gauze filter.
5. hydrocarbon adsorbent equipment as claimed in claim 4, the mesh wire diameter of wherein said wire gauze filter are about 0.01～0.07 inch, and the every linear inch of wherein said wire gauze filter comprises about 8 * 8～about 20 * 20 twines.
6. hydrocarbon adsorbent equipment as claimed in claim 4, wherein said wire gauze filter are selected from stainless steel, Fe-Cr-Al alloy, titanium, aluminium, nylon, polypropylene, PVC, ABS and polyethylene.
7. hydrocarbon adsorbent equipment as claimed in claim 6, wherein said wire gauze filter carries out bottom through metal oxide priming coat, metal fever electric arc spraying bottom, metallic thermal arc sprayed layer and metal oxide priming coat, sol solution priming coat and applies or preliminary treatment, perhaps through the acid etching preliminary treatment, and describedly apply or pretreated wire gauze filter scribbles described hydrocarbon adsorbent coating through bottom.
8. hydrocarbon adsorbent equipment as claimed in claim 7, wherein said metal fever electric arc spraying bottom is selected from Ni, Al, Ni/Al, Ni/Cr, Ni/Cr/Al/Y, Co/Cr, Co/Cr/Al/Y, Co/Ni/Cr/Al/Y, Fe/Al, Fe/Cr, Fe/Cr/Al, Fe/Cr/Al/Y, Fe/Ni/Al, Fe/Ni/Cr, 300 and 400 series stainless steels.
9. hydrocarbon adsorbent equipment as claimed in claim 8, wherein said wire gauze filter bottom is coated with described metallic thermal arc sprayed layer and refractory oxides layer.
10. hydrocarbon adsorbent equipment as claimed in claim 1, wherein said device comprise two protection filter screens, and described filter screen is positioned at described base material both sides.
11. in the automotive air intake system; described gas handling system comprises the air intlet of air cleaner, described air cleaner upstream and the air outlet slit in described air cleaner downstream; described air outlet slit is with the air guide engine; and hydrocarbon adsorbent is arranged between described air cleaner and the described air outlet slit; improvement comprises that wherein said hydrocarbon adsorbent is coated on the porous substrate, and at least one protection filter screen is adjacent with described porous substrate.
12. as the hydrocarbon adsorbent equipment of claim 11, the porous substrate that wherein said hydrocarbon adsorbent applies has one and is positioned at described porous substrate downstream and the protection filter screen adjacent with described porous substrate.
13. as the hydrocarbon adsorbent equipment of claim 11, the porous substrate that wherein said hydrocarbon adsorbent applies has one and is positioned at described porous substrate upstream side and the protection filter screen adjacent with described porous substrate and one and is positioned at described porous substrate downstream and the protection filter screen adjacent with described porous substrate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US68648605P | 2005-06-01 | 2005-06-01 | |
| US60/686,486 | 2005-06-01 | ||
| US11/440,266 | 2006-05-23 |
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| CN201410332424.8A Division CN104128068A (en) | 2005-06-01 | 2006-05-31 | Coated screen adsorption unit for controlling evaporative hydrocarbon emissions |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106481488A (en) * | 2015-08-31 | 2017-03-08 | 福特环球技术公司 | Induction system including passive adsorption hydrocarbon trap |
| CN108104911A (en) * | 2017-12-17 | 2018-06-01 | 斯凯伦动力设备科技（兴化）有限公司 | A kind of internal combustion generator waste discharge treatment device |
| CN114364870A (en) * | 2019-08-08 | 2022-04-15 | 卡尔冈碳素公司 | Sorbent device for air intake |
| CN114687892A (en) * | 2017-06-28 | 2022-07-01 | 巴斯夫公司 | Evaporative emission device and adsorbent |
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2006
- 2006-05-31 CN CNA2006800282069A patent/CN101232934A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106481488A (en) * | 2015-08-31 | 2017-03-08 | 福特环球技术公司 | Induction system including passive adsorption hydrocarbon trap |
| CN106481488B (en) * | 2015-08-31 | 2020-11-10 | 福特环球技术公司 | Inductive system including a passively adsorbing hydrocarbon trap |
| CN114687892A (en) * | 2017-06-28 | 2022-07-01 | 巴斯夫公司 | Evaporative emission device and adsorbent |
| CN114687892B (en) * | 2017-06-28 | 2024-04-26 | 巴斯夫公司 | Evaporation and discharge device and adsorbent |
| CN108104911A (en) * | 2017-12-17 | 2018-06-01 | 斯凯伦动力设备科技（兴化）有限公司 | A kind of internal combustion generator waste discharge treatment device |
| CN114364870A (en) * | 2019-08-08 | 2022-04-15 | 卡尔冈碳素公司 | Sorbent device for air intake |
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