GB2034596A - Contact device for treating fluids - Google Patents
Contact device for treating fluids Download PDFInfo
- Publication number
- GB2034596A GB2034596A GB7934973A GB7934973A GB2034596A GB 2034596 A GB2034596 A GB 2034596A GB 7934973 A GB7934973 A GB 7934973A GB 7934973 A GB7934973 A GB 7934973A GB 2034596 A GB2034596 A GB 2034596A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coils
- fluid
- wire
- coil
- active material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000012530 fluid Substances 0.000 title claims abstract description 36
- 239000011149 active material Substances 0.000 claims abstract description 28
- 238000006555 catalytic reaction Methods 0.000 claims abstract description 10
- 239000003054 catalyst Substances 0.000 claims description 38
- 239000011248 coating agent Substances 0.000 claims description 20
- 238000000576 coating method Methods 0.000 claims description 20
- 229910045601 alloy Inorganic materials 0.000 claims description 19
- 239000000956 alloy Substances 0.000 claims description 19
- 238000004804 winding Methods 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 14
- 229910052782 aluminium Inorganic materials 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 11
- 239000006185 dispersion Substances 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 229910052804 chromium Inorganic materials 0.000 claims description 8
- 239000007789 gas Substances 0.000 claims description 8
- 239000004411 aluminium Substances 0.000 claims description 7
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical group [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- 239000000919 ceramic Substances 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 238000002485 combustion reaction Methods 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 239000001996 bearing alloy Substances 0.000 claims description 2
- 238000001035 drying Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 239000002243 precursor Substances 0.000 claims 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 24
- 229910052697 platinum Inorganic materials 0.000 description 11
- 239000000758 substrate Substances 0.000 description 10
- 239000010948 rhodium Substances 0.000 description 9
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 8
- 229910052703 rhodium Inorganic materials 0.000 description 8
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 7
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 6
- 239000011651 chromium Substances 0.000 description 6
- 229910010293 ceramic material Inorganic materials 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000001294 propane Substances 0.000 description 4
- 229910052727 yttrium Inorganic materials 0.000 description 4
- 238000007792 addition Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000003870 refractory metal Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- NGDQQLAVJWUYSF-UHFFFAOYSA-N 4-methyl-2-phenyl-1,3-thiazole-5-sulfonyl chloride Chemical compound S1C(S(Cl)(=O)=O)=C(C)N=C1C1=CC=CC=C1 NGDQQLAVJWUYSF-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000013375 chromatographic separation Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000010285 flame spraying Methods 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 235000000396 iron Nutrition 0.000 description 1
- 229910000953 kanthal Inorganic materials 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052762 osmium Inorganic materials 0.000 description 1
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 150000003057 platinum Chemical class 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
- B01J35/58—Fabrics or filaments
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Catalysts (AREA)
Abstract
A device for the treatment of fluids e.g. by catalysis in which the fluid is caused to contact the device comprises a plurality of substantially parallel elongate helically wound coils of wire connected together by a connecting member to form a sheet of interconnected coils. In the case where the device is used for the treatment of the fluid by catalysis, the wire is made from, or coated with, a catalytically active material. <IMAGE>
Description
SPECIFICATION
Improvements in or relating to fluid treatment devices
This invention relates to devices for use in the treatment of fluids by interaction with a solid surface such as catalyst devices.
U.K. Patent Specification No. 2000 045A which corresponds to U.S. Patent Application Serial No. 916,561 (filed 19th June 1978) and to West German OLS No. 2862843 discloses, in a specific embodiment, a particular form of supported catalyst where the substrate is a wire form wound in to a helical coil with its windings extending progressively along a common axis. A number of important advantages follow from making catalyst supports in this way. In particular, wide ranging adjustment of important parameters such as exposed surface area, resistance to fluid flow, mass and heat conducting properties of the substrate can be achieved, without the constraint normally imposed by difficulties of coating a wire configuration substrate by contact with material dispersed in a liquid medium.Further, using a metallic substrate, a high degree of high temperature corrosion resistance can be achieved so that, for example, a substrate of aluminium bearing ferritic alloy without an yttrium addition can give satisfactory performance and durability in the severe environment of a motor vehicle exhaust system.
We have further appreciated that these advantages, whilst of principal significance in the manufacture and use of supported catalysts for satisfactory performance and durability in the catalytic purification of exhaust gases from motor vehicles, also have significance in any system (whether employing catalysis or not) where fluids are to be treated by passage over, and interaction with, a solid surface, and control of the above mentioned parameters is important. Examples, of other such systems where devices constructed in accordance with the present invention may be useful are in chromatographic separations, and processes where the solid surface material has an affinity for a constituent of the fluid flowing over it and is employed to separate out that constituent from the fluid.
In a first aspect, the present invention provides a device for use in the treatment of a fluid by passing the fluid over a solid surface with which the fluid interacts, which device comprises a plurality of elongate helically wound coils of wire-form arranged with their longitudinal axes substantially parallel to one another and interconnected by a connecting member to form a sheet of interconnected coils.
Preferably the space between adjacent windings of each coil is less than the diameter of the wire-form.
Each coil may be fabricated in a helical configuration from corrugated wire-form. The corrugation may be superimposed along the length of the wire-form so that, in each winding of the coil, the space between adjacent parts of the wire-form varies as a consequence of the corrugation. The pitch of the corrugation may be arranged in relation to the diameter of the coil and the pitch of the winding of the coil so that the peaks of the corrugation in each winding occur adjacent a peak in the next succeeding winding of the coil.
The preferred use of the device is in the treatment of a fluid by catalysis; in this case at least a surface of the coils comprises a catalytically active material. For example, each coil may be made of a catalytically active material or may carry a coating of catalytically active material. In a particular embodiment, one or more, but not all, of the coils may carry a coating of a first catalytically active material and the remaining coils may carry a coating of a different catalytically active material.
The sheet of coils may be assembled to form a fluid permeable body through which the fluid to be treated can flow in contact with the surfaces of the coils. One or more sheets of interconnected coils may be laid (folded or wound) on to itself, or on to other such sheets of interconnected coils, to form the fluid permeable body through which the fluid to be treated can flow in contact with the surface of the, or each, coil.
Preferably the wire-form is made of an aluminium bearing iron base alloy (available in the U.K. under the
U.K. Registered Trade Mark FECRALLOY). Such a metal alloy suitable for use in the present invention may be found within the alloy specification of a composition by weight of 10 to 30% Cr, 1 to 10% Al, 0 to 0.5% C, and the balance Fe.
Where resistance to high temperature embrittlement is important such alloys are made within the specification of a composition by weight of up to 20% Cr, 1 to 10% Al, 0.1 to 3.0% Y and the balance Fe.
Where a degree of high temperature embrittlement can be tolerated, as for example where a helical coiled wire configuration is employed, higher chromium content up to 25% by weight may be employed. The particularly preferred composition is a FECRALLOY (Registered Trade Mark) alloy having 15.50 to 16.50% Cr, 4.6 to 5.6% Al, 0.3 to 1.0% Y and the balance Fe.
The above mentioned alloys may include additions of Co and/or Ni and it is envisaged that such inclusions should be limited to the range 0 to 3% by weight of each element. However, acceptable performance may be achieved with these additions in the range 0 to 5% Co, and 0 to 5% Ni.
An alternative alloy is that sold under the U.K. Registered Trade Mark KANTHAL DSD. A typical example of such an alloy has an appropriate composition by weight of 22.5% Cr, 4.5% Al, 2.0% Co, 0.1% C and the balance Fe.
Preferably the aluminium bearing alloy has a ceramic layer on its surface. Preferably the ceramic material is bonded to the surface of the wire-form by heat treatment. The ceramic material may, for example, be silica or a refractory metal oxide such as alumina, ceria and yttria. The preferred ceramic material is alumina, which is bonded to the wire-form by heat treatment.
Preferably heat treatment, either before or after or both before and after coating with the porous ceramic, is carried out in the presence of oxygen to form a substantially alumina layer on the surface of the alloy wire form from aluminium within the alloy.
Catalytically active material, when required, may be deposited upon a plurality of coils which are then assembled together to form the sheet of interconnected coils. The catalytically active material may be deposited either after pre-coating of the substrate alloy with porous ceramic material or may be deposited simultaneously with the porous ceramic material.
There are many ways of applying the catalytically active materials to a substrate such as, for example, sputtering techniques using gaseous discharge, plasma coating techniques, flame spraying technqiues, wash coating techniques, vapour deposition techniques, and sintering techniques. The preferred way of depositing a catalyst onto the coils is that described in our U.K. Patent Application No. 43435/75 which corresponds to U.S. Patent Application Serial No. 733,152 (filed 18th October 1976) and to West German OLS
No. 26 47 702.
In a second aspect the invention provides a method of manufacturing a device for use in the treatment of a fluid which comprises
(i) arranging one or more elongate helically wound coils of wire with their longitudinally axes substantially parallel to one another and interconnecting the coils with a connecting member to form a sheet of interconnecting coils; and
(ii) providing at least a surface of the coils with a catalytically active material.
Preferably step (ii) comprises coating the coils with a dispersion containing the catalytically active material or a precursortherefor, thereby to coat the wi re-form with the dispersion, ensuring that the whole extent of the surface of the coils to be coated is contacted by the dispersion, and heat treating to provide the coils with a coating containing the catalytically active material.
The preferred method of carrying out the above coating comprises contacting the coils as a batch with the dispersion, removing the batch from contact with the liquid dispersion, removing excess liquid by shaking which causes relative movement between the discrete coils and thereby frees excess liquid trapped by surface tension effect at points of contact between adjacent coils, and drying.
In a third aspect the invention provides a method of treating a fluid by catalysis comprising the steps of causing the fluid to flow through a catalyst device which comprises a plurality of elongate helically wound coils, at least the surface of which comprises a catalytically active material interconnected by a connecting member to form a sheet of interconnected coils and fabricated into a fluid permeable body through which the fluid in contact with the surface of the, or each, coil.
Preferably, the fluid comprises the exhaust gases of an internal combustion engine.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Figures 1,2 and 4 illustrate three types of coils for use in a catalyst device constructed in accordance with the present invention.
Figure 3 illustrates the wire-form used to produce the coil of Figure 2.
Figure 5 illustrates a catalyst device according to the present invention made from a number of coils of the type shown in Figures 1, 2 or 4, interconnected to defined sheet of interconnected coils.
Figure 6 illustrates a catalyst device made from a sheet of interconnected coils as shown in Figure 5.
In the following embodiments of the invention the final product is to be used for the treatment of the exhaust gases of internal combustion engines by catalysis. It is to be understood however that the catalyst devices of the present invention may be useful in other industrial processes requiring supported catalytically active material.
Referring to Figure 1, there is shown a helical coil 10 made from a 0.040 ins (1.0 mm) diameter circular section wire 11 wound along an axis to form a coil which measures 3.0 ins (76.2 mm) long x 0.25 ins (6.4 mm) outside diameter. The pitch of the windings is approximately 0.039 ins (1.0 mm).
The wire is made of "FECRALLOY" alloy (U.K. Registered Trade Mark) having a composition (by weight) of 4.6 to 5.6% Al, 15.50 to 16.50% Cr, 0.3 to 1.0% Y, and the balance Fe. A predominantly alumina layer is formed on the surface of the wire and catalytically active material is deposited on the alumina layer as described in our U.K. Patent Application No. 43435/75 which corresponds to U.S.Patent Application Serial No.733,152 (filed 18th October 1976) and to West German OLS No.2647702. In a particular example described in the specification accompanying the latter mentioned applications and suitable for use in manufacturing catalyst devices of the present invention, alumina, prepared by a vapour condensation method, is formed into a sol by admixture with water and the sol mixed with a solution of yttrium nitrate in water to form a "mixed sol". A platinum salt is added to the mixed sol to give a dispersion which is applied to a pre-oxidised FECRALLOY alloy substrate. The thus coated substrate is subsequently fired to provide a coating containing platinum as the catalytically active material. Other techniques of applying a catalyst to the coil 10 may be used.
Referring to Figure 2 there is shown an alternative coil manufactured from the same type of alloy wire 0.02 ins (0.5 mm) diameter and wound into a coil 0.125 ins (3.0 mm) diameter by 1.5 ins (40 mm) long with a pitch of 0.11 ins (2.8 mm). The wire, used to make the coil 10 of Figure 2 is shown in Figure 3. From Figure 3 it will be seen that the wire 11 has superimposed along its length a corrugation 12 prior to it being wound into a coil. The corrugation 12 has a pitch of typically 0.13 ins (3.5 mm) and the dimension measured from peak to peak 14 is typicaily 0.04 (1.0 mm). The corrugations 12 imparts strength to the thin wire 11 and also if the peak 13, 14 of the corrugation 12 of each winding are arranged to coincide with peaks 13, or 14 in the next adjacent winding serve to prevent nesting of adjacent coiled members.Here again a surface coating and a catalytically active material is applied to the wire 11 in exactly the same way as described in connection with
Figure 1.
The coils shown in Figures 1 and 2 may be of uniform pitch as shown in Figures 1 and 2 or the pitch may vary along the length of the coil as shown in Figure 3. In the case of the coil shown in Figure 2, the pitch of the corrugations may be altered so that the peaks 13, 14 of each winding coincide.
Referring to Figure 5 a plurality of coils 10 made in the form as shown in any one of Figures 1,2 or 4 are assembled with their longitudinal axes extending substantially parallel to one another. The coils 10 are connected together to form a sheet of interconnected coils by two pairs of wires 16. The wires are woven or platted around each coil 10. That is to say, each wire passes successively over and under adjacent coils 10.
The coils may touch along their length or be spaced apart.
A continuous length of a sheet of interconnected coils 10 as illustrated in Figure 5, may be laid or wound on itself to form a catalyst device. For example, a catalyst device may be formed by winding the sheet of interconnected coils 10 spirally onto itself or onto a spool or former to produce one or more layers.
Alternatively, the catalyst device may be formed by laying the sheet of interconnected coils onto itself in a zig-zag way or by laying two or more discrete sheets of interconnected coils onto each other to define a fluid permeable body.
Preferably the coils 10 have a surface coating and catalytically active material applied to them prior to assembly into a sheet of interconnected coils. In some cases it may be possible to coat them after they are assembled into the sheet of interconnected coils 10.
The diameter of the wire 11 and size of the coils 10 (i.e. length, diameter and pitch of the coil) may be varied to suit any particular process. In particular, these parameters can be varied to meet desired pressure-drop specifications for the intended use of catalyst device. By varying these parameters one effectively varies the total effective area available to support a catalyst.
Preferably the cross-sectional shapes of the bore of the coils is a circle, although it may be of any desired shape, such as for example, triangular, rectangular, or polygonal achieved by winding the wire-form helically along a suitably shaped former. The terms "helical" and "helically" as used herein is taken to embrace coils wound along an axis irrespective of the shape of the bore of the coil. The coils may be formed on a conventional spring winding machine. The coils may be of uniform diameter or tapered if desired.
It is preferred to make the wire-form of a metal, for example steels; refractory metal carbides, for example
WC, TiC, TaC; aluminium and aluminium alloys, stainless steels and stainless irons. The wire-form may be drawn wire or an extruded rod.
It may be possible in some instances to use a ceramic filamentary member, although it is thought that such a route of manufacture would not be as easy as producing the components from metal wire, because of the need to fabricate the components in a green (plastic) state and then fire them to produce the finai form.
Catalyst devices constructed according to the present invention are useful in the treatment of exhaust gases of internal combustion engines by catalysis and in particular for trapping and treating soot products in the exhaust gases of diesel engines by catalysis, and the catalytic reduction of nitrogen oxides and catalytic oxidation of hydrocarbons and carbon monoxide in engine exhaust gases.
An important advantage that resuits from making the catalyst devices in the form of a number of coils in accordance with the present invention is that one can apply different catalytically active materials to different coils if one so desires. For example, one can construct a composite catalyst device using two or more sets of identical coils assembled to form the sheet of interconnected coils with different catalytically active materials deposited on each set of coils. For example a catalyst device may be constructed with some of the coils carrying one metal from the platinum group of metal (piatinum, osmium, iridium, palladium, rhodium, ruthenium) whilst the others carry a different metal from the platinum group.
In a specific example, a catalyst device constructed in accordance with the present invention for the treatment of exhaust gases of an internal combustion engine by catalysis may have some coils coated with platinum and the others coated with rhodium. In the past it has been usual to put down the platinum and rhodium as a common coating with platinum sites closely adjacent the rhodium sites. We have observed that after prolonged use the platinum becomes less effective at catalysing the oxidation of the hydrocarbons.
Examination of the surface of the catalyst reveals that active platinum sites are lost, but we have found that this loss does not occur to the same extent when the rhodium and platinum are deposited on separate coils.
Tests involving the oxidation of propane were carried out by flowing a slug of propane/oxygen carried in a nitrogen stream over two types of supported catalyst. One supported catalyst was a Pt/Rh mixed catalyst on a ceramic coated FECRALLOY alloy substrate (shown as Catalyst A below), the other comprised separate Pt and Rh catalysts on separate coiled members made of ceramic coated FECRALLOY alloy assembled to constitute a common catalyst (shown as Catalyst B below). The catalyst volume was displaced 100,000 times per hour by the propane/oxygen slug. The results are shown below.
Temperature required for
Type of 100% oxidation of propane supported catalyst (see text)
Catalyst after heating
New catalyst in air at 1 ,0000C for 12 hours
A 350"C 500"C B 400"C 400"C It is thought that the problem of the deterioration of the efficiency of the platinum as a catalyst may also apply to the commercial production of nitric acid from ammonia where platinum and rhodium are used as the catalysts. Therefore a catalyst bed made up of two sets of coils, each set of which either carries platinum or rhodium may be useful in the production of nitric acid.
The present invention may of course be useful in a wide variety of chemical processes involving treatment of fluids by interaction with a solid surface.
Claims (20)
1. A device for use in the treatment of a fluid which comprises a plurality of elongate helically wound coils of wire-form arranged with their longitudinal axes substantially parallel to one another and interconnected by a connecting member to form a sheet of interconnected coils.
2. A device according to claim 1 wherein the space between adjacent windings of each coil is less than the diameter of the wire-form.
3. A device according to either of the preceding claims wherein each coil is fabricated in a helical configuration from corrugated wire-form.
4. A device according to claim 3 wherein the corrugation is superimposed along the length of the wire-form so that, in each winding of the coil, the space between adjacent parts of the wire-form varies as a consequence of the corrugation.
5. A device according to claim 4 wherein the pitch of the corrugation is arranged in relation to the diameter of the coil and the pitch of the winding of the coil so that the peaks of the corrugation in each winding occur adjacent a peak in the next succeeding winding of the coil.
6. A device according to any of the preceding claims wherein at least a surface of the coils comprises a catalytically active material.
7. A device according to claim 6 wherein each coil carries a coating of catalytically active material.
8. A device according to claim 7 wherein one or more, but not all, of the coils carry a coating of a first catalytically active material and the remaining coils carry a coating of a second and different catalytically active material.
9. A device according to any of the preceding claims wherein the sheet of coils is fabricated in the form of a fluid permeable body through which a fluid to be treated can flow in contact with the surfaces of the coils.
10. A device according to any of the preceding claims wherein the wire-form is made of an aluminium bearing iron base alloy.
11. A device according to claim 10 wherein the alloy has a composition by weight of 10 to 30% Cr, 1 to 10% Al, 0 to 0.5% C, and the balance Fe.
12. A device according to claim 10 wherein the alloy has a composition by weight of up to 25% Cr, 1 to 10%AI,0.1 to 0.3%Yand the balance Fe.
13. A device according to any of claims 10 to 12 wherein the aluminium bearing alloy has a ceramic layer on its surface.
14. A device substantially as described herein with reference to any one of the accompanying drawings.
15. A method of manufacturing a device for use in the treatment of a fluid which comprises
(i) arranging one or more elongate helically wound coils of wire with their longitudinal axes substantially parallel to one another and interconnecting the coils with a connecting member to form a sheet of interconnecting coils, and
(ii) providing at least a surface of the coils with a catalytically active material.
16. A method according to claim 15 wherein step (ii) comprises coating the coils with a dispersion containing the catalytically active material or a precursor therefor, thereby to coat the wire-form with the dispersion, ensuring that the whole extent of the surface of the coils to be coated is contacted by the dispersion, and heat treating to provide the coils with a coating containing the catalytically active material.
17. A method according to claim 16 wherein the coils are coated by contacting the coils as a batch with the dispersion, removing the batch from contact with the dispersion, removing excess liquid by shaking which causes relative movement between the discrete coils and thereby frees excess liquid trapped by surface tension effect at points of contact between adjacent coils, and drying.
18. A method of manufacturing a device for use in the treatment of a fluid substantially as described herein with reference to any of the examples.
19. A method of treating a fluid by catalysis which comprises the steps of causing the fluid to flow through a catalyst device which comprises a plurality of elongate helically wound coils, at least the surface of which comprises a catalytically active material interconnected by a connecting member to form a sheet of interconnected coils and fabricated into a fluid permeable body through which the fluid can flow in contact with the surface of the, or each, coil.
20. A method according to claim 19 wherein the fluid comprises the exhaust gases of an internal
combustion engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7934973A GB2034596B (en) | 1978-10-27 | 1979-10-09 | Contact device for treating fluids |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7842175 | 1978-10-27 | ||
| GB7934973A GB2034596B (en) | 1978-10-27 | 1979-10-09 | Contact device for treating fluids |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2034596A true GB2034596A (en) | 1980-06-11 |
| GB2034596B GB2034596B (en) | 1983-07-20 |
Family
ID=26269353
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7934973A Expired GB2034596B (en) | 1978-10-27 | 1979-10-09 | Contact device for treating fluids |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2034596B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0061304A1 (en) * | 1981-03-18 | 1982-09-29 | Johnson Matthey Public Limited Company | Three dimensional interstitial catalyst support, its manufacture and use |
| EP0088800A1 (en) * | 1981-09-18 | 1983-09-21 | Prototech Co | Low pressure-drop catalytic mat and method of preparing the same. |
| US4464482A (en) * | 1980-11-27 | 1984-08-07 | Johnson Matthey Public Limited Company | Three dimensional interstitial catalyst support and its manufacture |
| EP0198435A2 (en) * | 1985-04-17 | 1986-10-22 | BASF Aktiengesellschaft | Process for producing catalysts for exhaust gas depoisoning |
| GB2180466A (en) * | 1985-08-07 | 1987-04-01 | Univ Surrey | Technique for continuous performance of a reaction |
| EP0363185A1 (en) * | 1988-10-04 | 1990-04-11 | Cro Cat Cc | Catalysts |
| WO1999002263A1 (en) * | 1997-07-10 | 1999-01-21 | The University Court Of The University Of Dundee | Monolith |
-
1979
- 1979-10-09 GB GB7934973A patent/GB2034596B/en not_active Expired
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4464482A (en) * | 1980-11-27 | 1984-08-07 | Johnson Matthey Public Limited Company | Three dimensional interstitial catalyst support and its manufacture |
| EP0061304A1 (en) * | 1981-03-18 | 1982-09-29 | Johnson Matthey Public Limited Company | Three dimensional interstitial catalyst support, its manufacture and use |
| EP0088800A1 (en) * | 1981-09-18 | 1983-09-21 | Prototech Co | Low pressure-drop catalytic mat and method of preparing the same. |
| EP0088800A4 (en) * | 1981-09-18 | 1984-09-11 | Prototech Co | Low pressure-drop catalytic mat and method of preparing the same. |
| EP0198435A2 (en) * | 1985-04-17 | 1986-10-22 | BASF Aktiengesellschaft | Process for producing catalysts for exhaust gas depoisoning |
| EP0198435A3 (en) * | 1985-04-17 | 1988-11-30 | BASF Aktiengesellschaft | Process for producing catalysts for exhaust gas depoisoning |
| GB2180466A (en) * | 1985-08-07 | 1987-04-01 | Univ Surrey | Technique for continuous performance of a reaction |
| EP0363185A1 (en) * | 1988-10-04 | 1990-04-11 | Cro Cat Cc | Catalysts |
| WO1999002263A1 (en) * | 1997-07-10 | 1999-01-21 | The University Court Of The University Of Dundee | Monolith |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2034596B (en) | 1983-07-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4397772A (en) | Catalyst supports and fluid treatment devices | |
| US5332554A (en) | Exhaust purifying catalyst for use in an internal combustion engine and method of manufacturing same | |
| US6559094B1 (en) | Method for preparation of catalytic material for selective oxidation and catalyst members thereof | |
| US5721188A (en) | Thermal spray method for adhering a catalytic material to a metallic substrate | |
| KR101337934B1 (en) | Two-layer three-way catalyst | |
| US4318894A (en) | Apparatus for the catalytic purification of exhaust gases | |
| US5174968A (en) | Structure for electrically heatable catalytic core | |
| US5288975A (en) | Resistance adjusting type heater | |
| US5533167A (en) | Honeycomb heater element having front region adapted to heat quickly | |
| EP0452125B2 (en) | Heater and catalytic converter | |
| US5651088A (en) | Resistive honeycomb heater having locally quickly heated regions for use in an exhaust gas purification system | |
| GB2077136A (en) | Catalyst devices | |
| JPH03295184A (en) | Resistance adjustment type heater and catalyst converter | |
| EP1561509B1 (en) | Exhaust-gas purifying catalyst | |
| US4289657A (en) | Fluid treatment devices | |
| US5399841A (en) | Honeycomb heater | |
| GB2034596A (en) | Contact device for treating fluids | |
| EP0851797B1 (en) | Brazing of catalyzed converter bodies | |
| JP2997805B2 (en) | Honeycomb heater and exhaust gas purification device using the same | |
| WO1993021431A1 (en) | Heating means for catalyst unit | |
| US8062990B2 (en) | Metal catalyst carriers and catalyst members made therefrom | |
| CA2123191A1 (en) | Reinforced converter body | |
| JP5268653B2 (en) | Catalyst with improved activity behavior | |
| JPS6357092B2 (en) | ||
| US4330436A (en) | Catalyst supports and fluid treatment devices |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |