GB2370518A - Plasma gas purification using a metal hydroxide - Google Patents
Plasma gas purification using a metal hydroxide Download PDFInfo
- Publication number
- GB2370518A GB2370518A GB0030720A GB0030720A GB2370518A GB 2370518 A GB2370518 A GB 2370518A GB 0030720 A GB0030720 A GB 0030720A GB 0030720 A GB0030720 A GB 0030720A GB 2370518 A GB2370518 A GB 2370518A
- Authority
- GB
- United Kingdom
- Prior art keywords
- reactor
- metal hydroxide
- gas permeable
- permeable body
- plasma assisted
- 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.)
- Withdrawn
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/32—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by electrical effects other than those provided for in group B01D61/00
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- 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
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J19/087—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
- B01J19/088—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0892—Electric or magnetic treatment, e.g. dissociation of noxious components
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/60—Inorganic bases or salts
- B01D2251/604—Hydroxides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/404—Nitrogen oxides other than dinitrogen oxide
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/80—Employing electric, magnetic, electromagnetic or wave energy, or particle radiation
- B01D2259/818—Employing electrical discharges or the generation of a plasma
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- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J2219/0803—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
- B01J2219/0805—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
- B01J2219/0807—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges involving electrodes
- B01J2219/0809—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges involving electrodes employing two or more electrodes
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- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J2219/0803—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
- B01J2219/0805—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
- B01J2219/0807—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges involving electrodes
- B01J2219/0824—Details relating to the shape of the electrodes
- B01J2219/0826—Details relating to the shape of the electrodes essentially linear
- B01J2219/083—Details relating to the shape of the electrodes essentially linear cylindrical
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- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J2219/0803—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
- B01J2219/0805—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
- B01J2219/0807—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges involving electrodes
- B01J2219/0837—Details relating to the material of the electrodes
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- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J2219/0803—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy
- B01J2219/0805—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing electric or magnetic energy giving rise to electric discharges
- B01J2219/0845—Details relating to the type of discharge
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- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J2219/0873—Materials to be treated
- B01J2219/0875—Gas
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- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
- B01J2219/0894—Processes carried out in the presence of a plasma
Abstract
A substrate material for the plasma assisted processing of gaseous media, consisting of a metal hydroxide such as zirconium hydroxide, preferably with an aluminium hydroxide binder. A reactor utilising a gas permeable bed made of a metal hydroxide is described, wherein the reactor is characterised by means for constraining the gaseous media to pass through the metal hydroxide.
Description
Gas Purification
The present invention relates to the plasma assisted processing of gaseous media and, in particular, to the reduction of the emission of nitrogenous and carbonaceous combustion products from the exhaust gases from internal combustion engines.
One of the major problems associated with the development and use of internal combustion engines is the noxious exhaust emissions from such engines. Two of the most harmful materials, particularly in the case of diesel engines, are particulate matter (primarily carbon) and oxides of nitrogen (NOx)'Increasingly severe emission control regulations are forcing internal combustion engine and vehicle manufacturers to find more efficient ways of removing these materials in particular from internal combustion engine exhaust emissions.
Unfortunately, in practice, it is found that techniques which improve the situation in relation to one of the above components of internal combustion engine exhaust emissions tend to worsen the situation in relation to the other. Even so, a variety of systems for trapping particulate emissions from internal combustion engine exhausts have been investigated, particularly in relation to making such particulate emission traps capable of being regenerated when they have become saturated with particulate material.
Examples of such diesel exhaust particulate filters are to be found in European patent application EP 0 010 384; US patents 4,505, 107; 4,485, 622; 4,427, 418;
and 4, 276, 066 ; EP 0 244 061 ; EP 0 112 634 and EP 0 132 166.
In all the above cases, the particulate matter is removed from diesel exhaust gases by a simple, physical trapping of particulate matter in the interstices of a porous, usually ceramic, filter body, which is then regenerated by heating the filter body to a temperature at which the trapped diesel exhaust particulates are burnt off. In most cases the filter body is monolithic, although EP 0 010 384 does mention the use of ceramic beads, wire meshes or metal screens as well. US patent 4,427, 418 discloses the use of ceramic coated wire or ceramic fibres.
GB patent 2,274, 412 discloses a method and apparatus for removing particulate and other pollutants from internal combustion engine exhaust gases, in which the exhaust gases are passed through a bed of charged pellets of material, preferably ferroelectric, having a high dielectric constant (that is of the order of at least 1,000). In addition to removing particulates by oxidation, especially electric discharge assisted oxidation, there is disclosed the reduction of NOx gases to nitrogen, by the use of pellets adapted to catalyse
the NOX reduction as exemplified by the use of barium titanate as the ferroelectric material for the pellets.
Other plasma assisted gas processing reactors are known, a common feature of which is the use of a gas permeable bed of an active material, usually a ceramic made of an oxide material. Examples are glass, barium and other titanates, aluminas or zirconia.
Often, these oxides are prepared by processes which involve the formation and subsequent decomposition of an hydroxide of the metals concerned. For example, titania can be produced by adding aqueous ammonia to a solution
of titanium (IV) chloride, drying the precipitate and decomposing it by heating to form the titania. If it is desired to produce formed titania shapes, such as spheres or extrudates, then normally this is done in the hydroxide state and the shaped bodies are fired to produce the shaped oxide bodies. Similarly, in the case of alumina, aluminium hydroxide made by precipitation from an aluminium salt solution and subsequent thermal decomposition to the metal oxide. Other hydroxides such as boehmite (ALOOF) or A1203H20 can be decomposed to Al203 by heating.
However, the surface properties of the final bodies can be effected by the process conditions during the final stage of manufacture and as, in use, the effectiveness of the metal oxide materials as substrates for use in the plasma assisted processing of gaseous materials can be effected by the surface properties of the metal oxide materials, variations in the effectiveness of reactors using the materials also can occur.
It is an object of the present invention to provide improved materials for use in the plasma assisted processing of gaseous media.
According to the present invention in one aspect there is provided an improved substrate material for use in the plasma assisted processing of gaseous media, comprising a gas permeable body made of at least one metal hydroxide.
According to the invention in another aspect there is provided a reactor for use in the plasma assisted processing of gaseous media, comprising a reactor chamber
having an inlet and an outlet for a gaseous medium to be processed in the reactor, a gas permeable body positioned within the reactor chamber, means for constraining a gaseous medium to be processed within the reactor to pass through the gas permeable body and at least two electrodes by means of which there can be adapted across the gas permeable body a potential sufficient to excite an electric discharge in the gaseous medium as it passes through the gas permeable body of material, wherein the gas permeable body is made of at least one metal hydroxide active material.
A suitable metal hydroxide material is zirconium hydroxide, with or without aluminium hydroxide as a binder material.
Preferably the body of metal hydroxide material is in the form of a bed of particles of the metal hydroxide material.
The invention will now be described, by way of example, with reference to the accompanying drawing, which is a longitudinal section of a schematic reactor embodying the invention for the plasma assisted processing of a gaseous medium.
Referring to the drawing, a reactor 1 for the treatment of the exhaust gases from an internal combustion engine to reduce the emissions of pollutants such as carbonaceous and nitrogenous oxide combustion products therefrom consists of a chamber 2 which has an inlet stub 3 and an outlet stub 4 by means of which it can be connected into the exhaust system of an internal combustion engine, (not shown in the drawing). Within the chamber 2 are a cylindrical inner electrode 6 made of perforated stainless steel sheet and a co-axial
cylindrical outer electrode 14 which also is made out of perforated stainless steel sheet. The electrodes 6 and 14 are supported within the chamber 2 by electrically insulating supports 7 and 8. The space 11 between the electrodes 6 and 14 and supports 7 and 8 is filled with a bed of pellets illustrated highly diagrammatically at 12 made of a metal hydroxide. The insulating support 7 has a number of axially oriented holes 13 disposed around its periphery so that exhaust gases entering the reactor chamber 2 are directed into the space 15 between the outer electrode 14, the supports 7 and 8 and the wall of the reactor chamber 2. The exhaust gases are then constrained to pass radially through the bed of metal hydroxide pellets 12 before passing through the inner electrode 6 and leaving the reactor chamber 2. A high voltage feed-through 10 enables a potential from a source 9 sufficient to excite a plasma in the exhaust gases in the interstices between the pellets 12 of metal hydroxide material to be applied to the bed of pellets 12. A convenient potential for this purpose is a potential of about 10 kV to 30 kV, which may be a pulsed direct potential or a continuously varying alternating potential, or may be an interrupted continuous direct potential. Typically we employ a potential of 20 kV per 30 mm of bed depth.
A suitable metal hydroxide material for the removal of carbonaceous and nitrogenous combustion products from internal combustion engine exhaust gases is zirconium hydroxide. The pellets 12 may be of any convenient shape or form and may contain a binder of aluminium hydroxide.
Another metal hydroxide which can be used for the above purpose is titanium hydroxide.
Claims (9)
1. An improved substrate material for use in the plasma assisted processing of gaseous media, comprising a gas permeable body made of at least one metal hydroxide.
2. A substrate material according to Claim 1 wherein there is included a metal hydroxide binder material.
3. A reactor for use in the plasma assisted processing of gaseous media, comprising a reactor chamber having an inlet and an outlet for a gaseous medium to be processed in the reactor, a gas permeable body positioned within the reactor chamber, means for constraining a gaseous medium to be processed within the reactor to pass through the gas permeable body and at least two electrodes by means of which there can be adapted across the gas permeable body a potential sufficient to excite an electric discharge in the gaseous medium as it passes through the gas permeable body of material, wherein the gas permeable body is made of at least one metal hydroxide active material.
4. A reactor according to Claim 3 wherein the gas permeable body of metal hydroxide active material includes a second metal hydroxide binder material.
5. A reactor according to Claim 3 or Claim 4 wherein the metal hydroxide active material is zirconium hydroxide.
6. A reactor according to Claim 4 or Claim 5 wherein the metal oxide binder material is aluminium hydroxide.
7. A reactor according to any of Claims 4 to 7 adapted to form part of an internal combustion engine exhaust system.
8. A substrate material for use in the plasma assisted processing of gaseous media substantially as hereinbefore described.
9. A reactor for the plasma assisted processing of gaseous media substantially as hereinbefore described and with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0030720A GB2370518A (en) | 2000-12-15 | 2000-12-15 | Plasma gas purification using a metal hydroxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0030720A GB2370518A (en) | 2000-12-15 | 2000-12-15 | Plasma gas purification using a metal hydroxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0030720D0 GB0030720D0 (en) | 2001-01-31 |
| GB2370518A true GB2370518A (en) | 2002-07-03 |
Family
ID=9905229
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0030720A Withdrawn GB2370518A (en) | 2000-12-15 | 2000-12-15 | Plasma gas purification using a metal hydroxide |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2370518A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2398750A (en) * | 2002-12-09 | 2004-09-01 | Visteon Global Tech Inc | Air induction system incorporating hydrocarbon filter |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3983021A (en) * | 1971-06-09 | 1976-09-28 | Monsanto Company | Nitrogen oxide decomposition process |
| JPH09299740A (en) * | 1996-05-14 | 1997-11-25 | Akira Mizuno | Gas treatment by discharge plasma |
| GB2335869A (en) * | 1997-12-19 | 1999-10-06 | Aea Technology Plc | Plasma assisted gas processing with titania |
| GB2338660A (en) * | 1998-06-24 | 1999-12-29 | Aea Technology Plc | Optimisation of flow in gas treatment reactors |
-
2000
- 2000-12-15 GB GB0030720A patent/GB2370518A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3983021A (en) * | 1971-06-09 | 1976-09-28 | Monsanto Company | Nitrogen oxide decomposition process |
| JPH09299740A (en) * | 1996-05-14 | 1997-11-25 | Akira Mizuno | Gas treatment by discharge plasma |
| GB2335869A (en) * | 1997-12-19 | 1999-10-06 | Aea Technology Plc | Plasma assisted gas processing with titania |
| GB2338660A (en) * | 1998-06-24 | 1999-12-29 | Aea Technology Plc | Optimisation of flow in gas treatment reactors |
Non-Patent Citations (1)
| Title |
|---|
| WPI Abstract AN 1998-057113[06] & JP 09 299 740 A * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2398750A (en) * | 2002-12-09 | 2004-09-01 | Visteon Global Tech Inc | Air induction system incorporating hydrocarbon filter |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0030720D0 (en) | 2001-01-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| COOA | Change in applicant's name or ownership of the application | ||
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |