PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`•
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PC1)
`WO 92/01585
`
`(51) International Patent Oassification 5 :
`
`(11) International Publication Number:
`
`B60K 15/00, F02M 25/08
`
`Al
`
`{43) International Publication Date:
`
`6 February 1992 (06.02.92)
`
`(21) International Application Number:
`
`PCT/ G B91101269
`
`(22) International Filing Date:
`
`26 July 1991 (26.07.91)
`
`(7 4) Agent: RY AN, Edward, Terrence; BP International Limit-
`ed, Patents & Agreements Division, Chertsey Road, Sun-
`bury-on-Thames, Middlesex TW16 7LN (GB).
`
`(30) Priority data:
`9016419.5
`
`26 July 1990 (26.07.90)
`
`GB
`
`(71) Applicant (for all designated States except US): THE BRIT(cid:173)
`ISH PETROLEUM COMPANY PLC [GB/GB]; Britan(cid:173)
`nic House, I Finsbury Circus, London EC2M 7BA (GB).
`
`(72) Inventors; and
`(75) Inventors/ Applicants (for US only) : TENNISON, Stephen,
`Robert [GB/GB]; 62 Farleigh Road, New Haw, Wey(cid:173)
`bridge, Surrey KTIS 3HR (GB). FOSTER, Alan, Ivor
`[GB/GB]; 38 St. Leonard's Road, Amersham, Bucks,
`HB6 6DS (GB). NICHOLAS, David, Henry [GB/GB]; 8
`Warner Road, Walthamstow, London El7 7D2 (GB).
`WEATHERHEAD, Richard, Henry [GB/GB]; I Cab(cid:173)
`bell Place, Adlestone, Weybridge, Surrey KT15 2XL
`(GB).
`
`(81) Designated States: AT (European patent), AU, BE (Euro(cid:173)
`pean patent), BR, CA, CH (European patent), DE (Eu(cid:173)
`ropean patent), DK (European patent), ES (European
`patent), FR (European patent), GB (European patent),
`GR (European patent), IT (European patent), JP, KR,
`LU (European pa~ent), NL (European patent), SE (Eu(cid:173)
`ropean patent), US.
`
`Published
`With international search report.
`
`(54)Title: APPARATUS AND PROCESS FORVAPOUR RECOVERY
`
`(57) Abstract
`
`A canister (1) for attachment to a vehicle fuel tank to reduce hydro(cid:173)
`carbon emissions comprises a gas inlet (2), gas outlet (3) and vent (4) and
`contains a bed of adsorbent polymer (7) and a bed of carbon (8). The vent
`opens into the carbon bed and the gas inlet and outlet open into the polym(cid:173)
`er bed.
`
`BASF-1011
`U.S. Patent No. RE38,844
`
`

`

`I'
`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international
`applications under the PCT.
`·
`
`AT
`AU
`BB
`BE
`BF
`BG
`BJ
`BR
`CA
`CF
`CG
`CH
`Cl
`CM
`cs
`DE
`DK
`
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Canada
`Central African Republic
`Congo
`Swiu.crland
`Cote d'Ivoire
`Cameroon
`Cu:choslovakia
`Germany
`Denmark
`
`ES
`Fl
`FR
`GA
`GB
`GN
`GR
`HU
`IT
`JP
`KP
`
`KR
`LI
`LK
`LU
`MC
`
`Spain
`Finland
`France
`Oabon
`United Kingdom
`Guinea
`Greece
`Hungary
`Italy.
`Japan
`Democratic People's Republic
`of Korea
`Republic of Korea
`Liechtenstein
`Sri Lanka
`Luxembourg
`Monaco
`
`MG
`Madagascar
`Mali
`ML
`MN
`Mongolia
`MR
`Mauritania
`MW Malawi
`NL
`Netherlands
`Norway
`NO
`PL
`Poland
`Romania
`RO
`SD
`Sudan
`SE
`Sweden
`SN
`Senegal
`su+
`Soviet Union
`TD
`Chad
`TC
`Togo
`us
`United States of America
`
`It is not yet known for which States of the former Soviet Union any designation of the
`+
`Soviet Union has effect.
`
`.,,.,··.
`
`

`

`WO92/01S85
`
`1
`
`PCT/GB91/01269
`
`APPARATUS AND PROCESS FOR VAPOUR RECOVERY
`
`The present invention relates to the recovery of gasoline
`vapours from mixtures of gasoline vapour and air.
`Gasoline vapour is emitted from motor vehicles powered by
`gasoline engines as a consequence of displacing gasoline vapour from
`the fuel tank during refuelling (refuelling losses).
`It is also
`emitted as a consequence of evaporation from the engine and fuel
`system either when the vehicle is in operation or when standing
`after use (diurnal losses). The emission of gasoline vapour is
`considered to be undesirable.
`Manufacturers already fit carbon canisters to eliminate the
`diurnal losses and such an arrangement is disclosed for instance in
`GB l 416 336. The carbon adsorbs the vapour emitted when the engine
`is stationary after use. The carbon canister is then regenerated by
`drawing air through the canister using the vacuum generated in the
`engine inlet manifold so that the gasoline vapour recovered from the
`canister is mixed with the normal air/fuel mixture to the engine.
`The vapour emission when the vehicle is stationary is quite small so
`that a canister having a capacity of about 1 litre is thought to be
`satisfactory. During normal vehicle operation the vapours emitted
`are continuously returned to the engine.
`Refuelling an almost empty tank involves displacing a large
`amount of gas (corresponding to the volume of the fuel tank if it is
`being completely refilled) saturated with gasoline vapour although
`this only occurs approximately once every 600 km. This is
`equivalent to approximately 150-200 g of vapour for a typical
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`WO92/01585
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`PCT/GB91/01269
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`European car (60 L tank) depending on the composition of the vapour.
`There are proposals both in the US and in Europe to impose
`legal restrictions on the amount of gasoline vapour which may be
`released into the atmosphere during refueling. One method proposed
`to meet such legal requirements is the recycling of the vapour from
`the fuel tank connected to the engine back to the storage tank from
`which the vehicle is refueled. This however is an expensive
`procedure in view of the complex equipment needed, and the work
`required at numerous refueling stations, often with underground
`storage tanks.
`It would be desirable to find a simple method of
`dealing with the problem by an extension of the use of adsorbent
`canisters mounted in vehicles. There is however a problem in trying
`to eliminate gasoline vapour emission during refuelling by the use
`of canisters carried in the vehicle. Although the overall weight of
`the gasoline vapour to be adsorbed is quite small the requirement to
`trap this during the 2-3 minutes that it takes to fill a normal
`saloon car tank would make it necessary to use as much as 5 litres
`of the carbons currently in use. Such large quantities of carbon
`can not be conveniently be provided in the restricted engine
`compartment of modern saloon cars.
`One approach to reducing the size of the canister is to use a
`carbon with a high adsorptive capacity. However we have found that
`such carbons are not easily regenerated in use by drawing air
`through the carbon bed. They would adsorb a large quantity of
`gasoline vapour on the first cycle, but only small quantities
`thereafter. The optimum active carbon the adsorption of gasoline
`vapours is one which has a high pore volume with pores in the small
`mesopore range (approximately 2 nm diameter). This maximises both
`the adsorption capacity of the carbon and the regenerability
`resulting in the largest possible working capacity. However the
`working capacity for typical gasolines is still limited to
`approximately 5% weight predominantly by the difficulty of
`
`regenerating the bed.
`GB 1 416 336 discusses some of the disadvantages of the use of
`carbon and proposes to overcome them by replacing the carbon by a
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`WO 92/01585
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`PCT/GB91/01269
`
`3
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`5
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`particulate macroreticular, substantially non-ionogenic,
`water-insoluble polymer having a specified surface area, porosity
`and average pore diameter. Among the polymers which may be used are
`polymers of divinyl benzene.
`However we have found that such porous polymers are not
`satisfactory for use as gasoline adsorbents. The porous polymers
`have a good saturation capacity for gasoline vapour and are easily
`regenerated. However the lower molecular weight components of the
`gasoline vapour, such as propane and butane, are not held strongly
`
`10
`
`enough on the polymer and thus break through the adsorbent bed and
`escape into the atmosphere after a comparatively short time thereby
`
`restricting the working capacity of the bed.
`In principle it is always preferably to prepare an adsorbent
`
`from a single material so as to simplify the manufacturing process.
`We have however found that the use of two different adsorbent
`materials give sufficiently marked advantages to justify the
`increased complexity.
`According to the present invention a canister for attachment to
`a vehicle fuel tank, said canister comprising a body adapted to
`receive an adsorbent, and having a gas inlet adapted to be connected
`to a gasoline storage tank, a gas outlet adapted to be connected tc
`a gasoline engine, and a vent to the atmosphere, is characterised in
`that the canister contains a bed of adsorbent polymer and a bed of
`carbon arranged such that the vent opens into the bed of carbon and
`the gas inlet and gas outlet open into the bed of adsorbent polymer.
`The present invention further provides a motor vehicle with a
`gasoline engine having a canister defined as above.
`According to the present invention a method of adsorbing
`gasoline vapour from air comprises passing the mixture of air and
`gasoline vapour through a first bed of adsorbent polymer, and then
`through a bed of adsorbent carbon, and subsequently regenerating the
`adsorbent beds by passing a stripping gas first through the bed of
`
`adsorbent carbon and then through the bed of adsorbent polymer.
`According to another aspect of the present invention a process
`for operating a gasoline engine of a motor vehicle comprises passing
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`WO 92/01585
`
`/
`
`PCT/GB91/01269
`
`4
`
`air displaced from the fuel tank while refueling the vehicle through
`
`a first bed of adsorbent polymer, and then through a bed of an
`adsorbent carbon so as to adsorb high molecular weight components of
`
`the gasoline on the polymer and lower molecular weight components of
`the gasoline on the carbon, and subsequently operating the engine so
`
`5
`
`as to draw air though the bed of adsorbent carbon and then through
`the bed of absorbent polymer before feeding the air to the engine.
`The mixture of air and desorbed gasoline components will
`generally be blended will the normal gasoline/air fuel before the
`total mixture is passed to the engine.
`
`The adsorbent carbon may be any of the conventional active
`carbons already proposed for use in gasoline engines: However the
`
`use of the carbon in conjunction with the polymer adsorbent bed in
`
`the layered bed canister allows the use of a wider variety of active
`carbons where the requirement for the majority of pores to be small
`mesopores can be relaxed. Using conventional premium European
`gasoline the best results in the layered bed canister have been
`obtained with a highly microporous coconut shell carbon.
`Folymers which are suitable adsorbent polymers for gasoline
`vapour adsorption are disclosed in GB 1 416 336. This discloses the
`use of ,particulate macroreticular, substantially non-ionogenic,
`
`water-insoluble polymers having a specific surface area in the range·
`10 to 10000 m2/g, a porosity of 25% to 85%, and an average pore
`diameter of 2 nm to 2000 nm. Among specific polymers which may be
`used are those obtained by polymerising under macroreticular polymer
`producing conditions. The monomer charge is composed of
`ethylenically unsaturated monomer or monomers and containing from 2%
`
`to 100% by weight, based on the weight of the charge, of 1 or more
`of divinyl benzene, trivinyl benzene, alkyl vinyl benzenes having
`from 1 to 4 methyl or ethyl groups substituted in the benzene
`nucleus, and alkyl divinyl benzenes having from 1 to 3 methyl or
`ethyl groups substituted in the benzene nucleus.
`
`We believe that the surface area of the polymer is preferably
`in the range 200 to 2000 ~2/g, and that the polymer should contain a
`significant volume of pores in the range 1 nm to 50 nm for
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`WO 92/01585
`
`PCT/GB91/01269
`
`5
`
`adsorption purposes, as well as larger pores for gas transfer.
`
`A particularly preferred polymer is a copolymer of a mixture
`
`containing a major amount of divinyl benzene and a minor amount of
`
`5
`
`ethyl styrene which is sold under the designation 11 Ambersorb XAD4 11
`by Rohm & Haas Inc.
`The quantities of adsorbent used will depend on the working
`
`adsorbing capacity of the polymer, the working aqsorbing capacity of
`the active carbon, the quantity of gasoline vapour to be adsorbed
`
`between each regeneration period and the time available for
`regeneration. For use in a canister useable in a normal size family
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`car the total volume of adsorbent may be in the range 500 ml to 5
`litres.
`
`The optimum amount of the two different adsorbents to be used
`will depend on the design of the canister. The designated ratios
`
`refer to the volume of adsorbent between the gasoline vapour inlet
`and the vent to atmosphere. This can be seen by reference to
`figures 1 and 2.
`In figure 1 which shows a canister with the vapour
`inlet (2) in the centre of the bed the polymer:carbon ratio refers
`to the volume of adsorbent between the vapour inlet (2) and the vent
`
`In the canister shown in figure 2 the ratio
`to atmosphere (4).
`refers to the total volume of adsorbent in the canister between the
`vapour inlet (12) and the vent to atmosphere (14). The optimum
`ratio of polymer to carbon will vary with the type of gasoline to be
`
`used but may be in the range 3:7 to 7:3, or preferably in the range
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`4:6 to 6:4, more preferably 4.5:5.5 to 5.5:4.5.
`The relative volumes of the two adsorbents may be adjusted to
`
`optimise the performance of the canister system for different types
`
`of gasoline used in different regions of the world. For the higher
`volatility fuels typically used in Europe a volume ratio of polymer
`to carbon of about 1:1 is preferred. For lower volatility fuels it
`is believed that polymer to carbon volume ratios of greater than 1:1
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`
`(ie larger relative amounts of polymer) will be desirable.
`Depending on the design of the canister and the disposition of
`
`the inlet and ven~, the ratios described above may correspond to a
`canister having a relatively large bed of adsorbent polymer and a
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`WO92/01585
`
`PCT/GB91/01269
`
`6
`
`relatively small bed of carbon. However this will not necessarily
`
`correspond to the most efficient use of the adsorbents.
`The invention will now be illustrated with reference to the
`drawings and the following experiments.
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`5
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`In the drawings:
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`Figure 1 is a diagrarnatic cross-sectional view of one form of a
`gasoline adsorbing canister for use in the present invention, and
`Figure 2 is a cross-sectional diagramatic view of an alternative
`form of gasoline canister according to the invention.
`Referring to Figure 1 a cylindrical canister (1) is provided
`
`with a gas inlet (2) extending downwardly into the body of the
`canister and opening into the canister through slots· at its lower
`end. A vapour outlet (3) is provided at the top of the canister. A
`vent (4), which may allow air to both enter or leave the canister is
`provided at the lower end. A perforated plate (5) is mounted above
`springs (6) which serves to urge the plate (5) upwards so as to keep
`any adsorbent material in the upper part of the canister compressed
`into its packed state. The upper part of the canister between the
`
`connection to the vehicle inlet manifold (3) and the vapour i_nlet
`(2) is filled with a bed (7) of adsorbent polymer particles. The
`lower part of the canister is filled with two layers. The. upper.
`layer (1) is of the porous polymeric adsorbent whilst the lower
`layer (8), closest to the atmospheric vent (4) is filled with carbon
`adsorbent such that the volume ratio of the volume of bed (1) to bed
`(8) is most preferably in the ratio 4.5:5.5 to 5.5:4.5.
`In use in a motor vehicle the inlet (2) is connected by piping
`and appropriate valves to the vehicle's fuel tank connected by
`piping and appropriate valves to the vehicles fuel tank and to the
`
`vents from the vehicles fuel inlet system and crankcase. The outlet
`(3) is connected by piping and an appropriate valve to the engine,
`for example it may be connected as a bleed to a carburettor. The
`
`vent (4) provides for the inlet or outlet of gas to the outside
`
`air. When the motor vehicle is refueled gas displaced from the fuel
`
`tank enters the canister through inlet (2). Outlet (3) can be
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`
`closed so that no air is drawn through it to the engine but this is
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`WO92/01585
`
`PCT /GB91/01269
`
`7
`
`not essential. Gasoline vapour evaporating from the fuel tank will
`pass through inlet (2) into the canister. It will initially contact
`the absorbent polymer and
`then diffuse through this into the
`
`adsorbent carbon. When the motor is running air will be drawn in
`through the vent (4) and will sweep adsorbed gasoline vapour
`components out of the adsorbent carbon. The air will then pass
`through the adsorbent polymer to the engine by way of outlet (3) so
`regenerating the adsorbent materials in the canister.
`Figure 2 shows an alternative design of canister for use
`particularly in reducing emissions during the refueling of motor
`vehicles. The canister (11) is provided with a gas inlet (12) and a
`gas outlet (13) together with a vent (14). These are all provided
`at the top of the canister. A metal divider (15) covered with an
`asbestos insulating sheet (16) divides canister (11) so that an
`elongated flow path is provided between the inlet (12) and outlet
`(13) on the one hand and the vent (14) on the other. The canister
`is filled with two types of adsorbent material, namely a bed of
`adsorbent polymer (17), and a similar bed of adsorbent carbon (18).
`Wire mesh or perforated plates (19) and glass fibre (20) hold the
`adsorbent particles in position.
`In use air containing gasoline vapour displaced from a motor
`vehicle fuel tank during refueling passes into the canister through
`inlet (12) and passes through the bed of adsorbent polymer (17) and
`then the bed of adsorbent carbon (18) to the vent (14) through which
`it is discharged to the atmosphere. When the canister is to be
`regenerated the connection to the fuel tank can be closed by a valve
`(not shown) and a connection is opened to the engine through outlet
`(13) by which air will be drawn into the canister through vent (14)
`so as to displace adsorbed gasoline vapour from the adsorbent
`particles and to transport it through outlet (13) to the engine.
`In the experiments set out below experiments identified by
`number are examples of the invention and experiments identified by
`letter are comparative tests not according to the invention.
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`Comparative Test A
`Tests were carried out on a Volkswagen car supplied fitted with
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`

`WO92/01585
`
`PCT/GB91/01269
`
`8
`
`a carbon adsorbent canister of the type shown in Figure l having a
`capacity of 1.1 litre and filled with a commercial particulate
`carbon adsorbent. The engine was subjected to cycles of (a)
`
`running, in which air was drawn through the canister into the engine
`and (b) standing, in which gasoline vapour from the fuel tank passed
`through the canister before air from the tank was vented to the
`atmosphere. After use for a considerable number of cycles so as to
`give a fully aged carbon,tests were carried out over six cycles to
`determine the working capacity for gasoline adsorption of the
`carbon. This was done by measuring weight increase during the
`period of gasoline adsorption. The result is shown in the Table.
`Comparative Test B
`An experiment was carried out as in Comparative Test A except
`that the carbon particles were removed from the canister which was
`then loaded with a gasoline adsorbing polymer (1.1 litre packed
`volume) which was a polymer of divinyl benzene containing some ethyl
`styrene sold under the commercial designation "Ambersorb XAD4".
`The working capacity of the polymer was determined as in
`Comparative Test A.
`Example 1
`An experiment was carried out as in Comparative Test B, except
`that the lower part of the canister connected to the fuel tank and
`the air feed to the engine was loaded with the carbon of Test A,
`while the upper part was loaded with the adsorbent polymer of Test
`B. Both adsorbents were fully aged.
`The relative quantities of gasoline-adsorbing polymer and
`absorbent carbon were 3:1 by packed volume.
`The working capacity of the mixture was determined as the mean
`of six cycles of the operation with a standard deviation of 3.54 g.
`The result is given in the Table.
`For comparison a predicted value of the working capacity was
`determined based on the measured capacities from Tests A and Band
`the relative amounts of carbon and polymer used in example 1. The
`
`results are given in Table 1.
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`WO92/01S8S
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`PCT/GB91/01269
`
`9
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`EXPERIMENT
`
`WORKING CAPACITY
`
`(g)
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`22
`
`29.2
`
`21. 5
`
`Test A
`
`Test B
`
`Example l
`
`Example 1
`(predicted)
`
`In addition to these tests with typical vehicle canisters,
`
`laboratory tests were carried out with the equipment described
`below. The two adsorbent beds (1 and 2) were contained in steel
`
`vessels that could be separated and weighed individually after each
`adsorption and desorption cycle. Each vessel was 4 cm in diameter
`and could hold up to 80 ml of adsorbent held in place between plugs
`of glass wool. The two beds were contained in a water bath
`
`maintained at 53C. The adsorption cycle was simulated by passing
`gasoline vapour, produced by bubbling 83 ml min of nitrogen through
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`200 ml Eurograde unleaded 95/85 gasoline held at 200C in a water
`bath, through the polymer bed and then the carbon bed in series.
`
`The temperature in the centre of each bed and the total flow from
`the second carbon bed was recorded as a function of time. The
`composition of the effluent gas was analysed by mass spectrometer.
`The adsorption cycle was assumed to be complete when the 29 peak in
`the mass spectrometer (mainly due to propane) reached l x 10-8 unts,
`ie partial breakthrough. The gas flow was then stopped and the two
`
`beds were isolated and weighed. The two beds were then returned to
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`the water bath.
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`WO 92/01585
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`PCT /GB91/01269
`
`10
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`Desorption was carried out by reversing the nitrogen flow
`through the two beds. An average flow rate of 485 ml/minutes was
`
`used for a fixed time of 40 minutes for the desorption cycle. After
`the 40 minutes the two beds were again removed from the water bath
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`and weighed.
`Comparative Tests C and D
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`Tests C and D (table 2) are not according to the present
`invention and show the breakthrough time in minutes and the working
`capacity in both% weight and g/litre for the tests where both
`vessels contained either 80 ml of the porous polymer, XAD4 (test C)
`
`or 80 mls of a typical extrudate active carbon recommended for use
`in evaporative loss canisters (test D).
`
`Examples 2 to 7
`
`Examples 2 to 7 (table 2) dernostrate the dramatic improvements
`in both the time to breakthrough and the working capacity when the
`first bed is filled with 80 ml of the porous polymer, XAD4, and the
`second bed with 80 ml of activated carbon.
`In Examples 2 the carbon
`is the recommended extrudate active carbon used in comparative test
`D.
`It can be seen from a comparison of tables 1 and 2 that the
`increase in the working capacity compared to both the
`polymer/polymer bed and the carbon/carbon-beds is almost identical
`to that found in the vehicle tests whilst the actual working
`capacities are slightly higher for the· laboratory test probably due
`to slight differences in the breakthrough criterion. This
`demonstrates the validity of the laboratory test method.
`
`Examples 3 to 7 demonstrate the use of different activated
`carbons in the second adsorbent bed. These materials were not
`selected using the normal criterion for evaporative emission
`canister carbons of maximising the small mesopore (2nm) volume but
`were typical microporous active carbons. It can be seen that the
`best perforance for the dual bed system was achieved with Sutcliffe
`
`Speakman AC610C, a highly microporous active carbon. The relative
`
`performance of the activated carbons in the dual bed system
`
`correlates better with the saturation butane capacity of the carbons
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`than the working capacity which are also shown in table 2. These
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`WO92/01585
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`PCT/GB91/01269
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`11
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`results demonstrate a second benefit of the dual be·d canister,
`
`namely that the carbon component can now be selected to maximise the
`
`butane adsorption capacity without the generally poorer regeneration
`
`capability of the microporous carbons influencing the working
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`capacity.
`
`Table 2 - Cyclic Ferformance of Laboratory Test -
`
`twin beds
`
`each of 80 ml capacity.
`
`Test Materials Breakthrough Working Capacity Butane Adsorption
`
`time
`(minutes) % weight g/litre Saturation Working
`% weight
`g/L
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`C XAD4/XAD4
`C ACl/ACl
`2 XAD4/AC45
`3 XAD4/610C
`XAD4/GAC616G
`XAD4/AS IV
`XAD4/WS IV
`
`4
`
`5
`
`6
`
`21.8
`
`26.0
`
`40.5
`
`42.2
`
`38.0
`
`36.0
`
`33.0
`
`7.0
`
`6.8
`
`11.0
`
`11. 7
`
`9.2
`10.9
`
`9.9
`
`27.6
`
`29.1
`
`44.8
`
`46.0
`
`42.2
`41. 7
`
`37.9
`
`32
`
`33
`
`39
`
`34
`
`30
`33
`
`33
`
`98
`
`63
`
`54
`
`50
`
`81
`63
`
`75
`
`Comparative Test E and Examples 7 and 8
`The same test conditions as used for tests C and D and Examples
`2 to 6 were used in the following examples of a less preferred form
`
`25
`
`In examples 2 to 6 the ratio of polymer
`of the present invention.
`to carbon was 50:50.
`In examples 7 to 8 the volume of adsorbent in
`
`the second bed has been reduced to 16 ml. The polymer:carbon
`
`volume ratio in tests F and G was 83:17.
`
`30
`
`35
`
`

`

`WO92/01S85
`
`PCT/GB91/01269
`
`12
`
`Table 3
`
`Test Materials Breakthrough Working Capacity
`% weight
`time (minutes)
`
`XAD4/XAD4
`E
`7 XAD4/SS208C
`XAD4/AC1
`
`8
`
`10.8
`12.5
`11. 6
`
`5.3
`5.9
`6.0
`
`As the total bed volume has been reduced from 160 mls to 96 mls
`the breakthrough times and working capacities in table 3 cannot be
`compared directly with those shown in table 2.
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`

`

`WO 92/01585
`
`- · 13 -
`
`PCT /GB91/01269
`
`Claims:
`
`1. A canister for attachment to a vehicle fuel tank, said canister
`
`comprising a body adapted to receive an adsorbent, and having a gas
`
`inlet adapted to be connected to a gasoline storage tank, a gas
`outlet adapted to be connected to a gasoline engine, and a vent to
`
`the atmosphere, is characterised in that the canister contains a bed
`of adsorbent polymer and a bed of carbon arranged such that the vent
`opens into the bed of carbon and the gas inlet and gas outlet open
`into the bed of adsorbent polymer.
`
`2. A canister according to claim l wherein the volume ratio of
`adsorbent between the gasoline vapour inlet and the vent to
`
`atmosphere is in the range 3:7 to 7:3.
`3. A canister according to Claim 2 wherein the volume ratio is in
`the range 4:5:5.5 to 5.5:4.5.
`4. A canister according to claim 1 wherein the canister contains a
`relatively large bed of adsorbent polymer and a relatively small bed
`
`of carbon.
`5. A canister according to anyone of the preceding claims wherein
`the adsorbent polymer is a particulate macroreticular substantially
`non-inorganic, water insoluble polymer having a specific surface
`area in the range 10 to 1000 rnHg, a porosity of 25% to 85%, and an
`
`average pore diameter of 2 nm to 2000 nm.
`6. A canister according to any one of the preceding claims wherein
`the polymer has a surface area in the range 200 to 2000 m2/g and
`contains pores in the range 1 to 50 nm.
`
`5
`
`10
`
`15
`
`20
`
`7. A canister according to any one of the preceding claims wherein
`the total volume of adsorbent is in the range 500 ml to 5 litres.
`
`25
`
`

`

`WO92/01585
`
`PCT/GB91/01269
`
`14
`
`8. A motor vehicle with a gasoline engine equipped with a
`
`canister, which canister is according to any one of the preceding
`
`claims.
`8. A method of adsorbing gasoline vapour from air comprises
`
`5
`
`passing the mixture of air and gasoline vapour through a first
`
`bed of adsorbent polymer, and then through a bed of adsorbent
`carbon, and subsequently regenerating the adsorbent beds by passing·
`
`a stripping gas first through the bed of adsorbent carbon and then
`through the bed of adsorbent polymer.
`10. A process for operating a gasoline engine of a motor vehicle
`comprises passing air displaced from the fuel tank while refueling
`
`10
`
`the vehicle through a first bed of adsorbent polymer, and then
`through a bed of an adsorbent carbon so as to adsorb high molecular·
`weight components of the gasoline on the polymer and lower molecular
`15 weight components of the gasoline on the carbon, and subsequently
`'
`operating the engine so as to draw air though the bed of adsorbent
`carbon and then through the bed of absorbent polymer before feeding
`the air to the engine.
`
`20
`
`25
`
`30
`
`35
`
`

`

`WO92/01585
`WO 92/01585
`
`PCT/GB91/01269
`PCT/GB91/01269
`
`1/1
`7/7
`
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`v'w'-O.P
`
`
`
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`
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`
`19
`
`11
`18
`15
`
`17
`17
`
`16
`16
`
`Fig.1
`Fig. 7
`
`
`
`

`

`INTERNATIONAL SEARCH REPORT
`Jruemational Application No
`
`PCT/GB 91/01269
`
`(If sev11nl dasslflcatlon symltols apply, Indicate all) 6
`I. CLASSIFICATION OF SUBJECT MATTER
`Acconllag to lntenatlonl Pate11t Classification (lrq or to ~II National Classification and IPC
`Int.Cl. 5
`B60K15/00 ; F02M25/08
`
`II, FIELDS SEARCIIED
`
`Classification System
`
`Int.Cl. 5
`
`Minimum Docume11tation Searchcd7
`
`Classification Symbols
`
`860K '
`
`F02M
`
`Documentation Searched other than Minimum Documentation
`to the Extent that such Documents are Included in the Fields SearchedR
`
`Ill. DOCUMENTS CONSIDERED TO BE RELEVANT9
`Category O
`
`Citation of Document, It with Indication, where appropriate, of the relevant pa~sagcs 12
`
`Relevant to Claim No.13
`
`A
`
`A
`
`A
`
`A
`
`A
`
`US,A,4 684 382 (ABU-ISA) 4 August 1987
`see the whole document ---
`EP,A,O 330 864 (ADAM OPEL AG) 6 September 1989
`see the whole document ---
`
`US,A,4 308 841 (KINGSLEY) 5 January 1982
`see abstract; claim 1; figure 1
`see column 3, line 47 - line 56
`---
`GB,A,1 416 336 (ROHM AND HMS COMPANY) 3
`December 1975
`cited in the application
`see claims 1,11
`---
`US,A,3 838 673 (CSICSERY ET AL) 1 October 1974
`see the whole document ---
`
`-!--
`
`1-5,8-10
`
`1-3,5-8
`
`1-4,8-10
`
`1,5,6,8,
`9
`
`1,4,8-10
`
`0 Special categories of cited documents : to
`• A" document defining the general state of the art which Is not
`considered to be of particular relevance
`"E" earlier document but published on or after .the International
`filing date
`'L" document which may throw doubts on priority claim(s) or
`which Is cited to establish the publicatmn date of another
`citation or othtt special rea.~on (as specified)
`"0" document referring to an oral disclosure, use, exhibition or
`other means
`"P" document published prior to the International flling date but
`later than the priority date claimed
`
`.. T.. huer document published after the international filing date
`or priority date and 1101 In conflict with the ap/clleatlon llut
`cited to understand the principle or theory un erlying the
`Invention
`.. X" dncument of particular relevance; the claimed invention
`cannot be considered novel or cannot be considered to
`Involve an Inventive step
`"V" document of particular relevance; the claimed Invention
`cannot be considered to Involve an inventive step when the
`document Is combined with one or more other such doeu-
`n1cnts, such c1,n1bination being obvious to a pc~on skilled
`In the art.
`"'&" document member of the same patent family
`
`IV. CERflFICATION
`Date of the Actual Completion of the International S!'arch
`25 OCTOBER 1991
`
`lnternalional Scarchin2 Authority
`
`EUROPEAN PATENT OFFICE
`
`Date of Mailin11 of this lnternaiios.l Yfcsicport
`
`Sil!,naturc or Authori1.ed Orrtcrr
`
`s. TOPP-BORN ~-&~
`
`

`

`Jntematlonal Applle2llon No
`
`PCT/GB 91/01269
`
`Relevant to Oalm No,
`
`1,4,8-10
`
`1,5,9,10
`
`1,2
`
`1,2
`
`Ill, DOCUMENTS CONSIDERED TO DE RELEVANT
`Otatlon of Document, with Indication, where appropriate, of the rclt!\llnt passages
`
`(CONTINUED FROM TIIE SECOND SHEEn
`
`Category O
`
`A
`
`A
`
`A
`
`A
`
`US,A,3 844 739 (ALFRY,JR.) 29 October 1974
`see the whole document
`US,A,4 289 513 (BROWNHILL ET AL.) 15 September
`1981
`see column 2, line 41 - column 3, line 36
`see column 4, line 66 - column 5, line 15
`see column 5, line