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US4774069A
Expired / Lapsed
US
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Process for the manufacture of nitric oxide
Assignee: Johnson Matthey PLC
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Filing: 1986-06-27
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Granted: 1988-09-27
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Expires: 2006-06-27
Abstract
Abstract A process for the manufacture of nitric oxide by the oxidation of ammonia using a catalyst (1) comprising platinum in which the ammonia conversion efficiency of the process is improved by the use of a palladium catchment trap (2) in which the conventional layers (8 and 10) of palladium scavenger-wire are adjacent to layers (7, 9 and 11) of interstitial (preferably woven) ceramics material. The preferred ceramics material consists of alumina, silica and boria. Also a catchment trap comprising layers of ceramics material for use in the process.
Inventors
- 👤 Jack R. Handley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:53
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/02; C22B11/021; C22B11/026; C22B11/028; C01; C01B; C01B21/00; C01B21/20; C01B21/24; C01B21/26; C01B21/267; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
94 words
A process for the manufacture of nitric oxide by oxidising ammonia in the presence of a catalyst comprising platinum and from 0 to 20 wt % of rhodium and from 0 to 40 wt % of palladium (based on the weight of alloy), the catalyst being located upstream from a palladium catchment trap for scavenging platinum or rhodium lost from the catalyst by volatilisation wherein the catchment trap comprises at least one interstitial layer of elongated elements made from palladium or an alloy of palladium adjacent at least one layer of interstitial ceramics material.
Claim 2
Dependent Claim
94 words
A process for the manufacture of nitric oxide by oxidising ammonia in the presence of a catalyst comprising platinum and from 0 to 20 wt % of rhodium and from 0 to 40 wt % of palladium (based on the weight of alloy), the catalyst being located upstream from a palladium catchment trap for scavenging platinum or rhodium lost from the catalyst by volatilisation wherein the catchment trap comprises at least one interstitial layer of elongated elements made from palladium or an alloy of palladium adjacent at least one layer of interstitial ceramics material.
Claim 3
Dependent Claim
27 words
A process according to claim 1 wherein the catchment trap comprises from 2 to 30 layers of palladium elongated elements interleaved by layers of interstitial ceramics material.
Claim 4
Dependent Claim
25 words
A process according to claim 1 wherein each layer of ceramics material comprises intercrossing ceramics threads which define the interstices of the interstitial ceramics material.
Claim 5
Dependent Claim
14 words
A process according to claim 3 wherein the threads make up a woven cloth.
Claim 6
Dependent Claim
21 words
A process according to claim 3 wherein the open area of of the interstitial ceramics material is from 20 to 60%.
Claim 7
Dependent Claim
48 words
A process according to claim 1 wherein the ceramics material comprises at least one compound selected from the group consisting of the oxides, borides, carbides, silicides, nitrides and silicates of aluminum, zirconium, boron, silicon, magnesium, titanium, yttrium, beryllium, thorium, manganese, lanthanum, scandium, calcium, uranium, chromium, niobium and hafnium.
Claim 8
Dependent Claim
28 words
A process according to claim 6 wherein the ceramics material is a composition comprising alumina, 0.1 to 30 wt % silica and 0 to 15 wt % boria.
Claim 9
Dependent Claim
12 words
A process according to claim 6 wherein the ceramics material comprises zirconia.
Claim 10
Dependent Claim
52 words
A catchment trap for use in the manufacture of nitric oxide by oxidising ammonia in the presence of a platinum-based catalyst wherein the catchment trap comprises at least one interstitial layer of elongated elements made from palladium or an alloy of palladium supported on at least one layer of interstitial ceramics material.
Claim 11
Dependent Claim
52 words
A catchment trap for use in the manufacture of nitric oxide by oxidising ammonia in the presence of a platinum-based catalyst wherein the catchment trap comprises at least one interstitial layer of elongated elements made from palladium or an alloy of palladium supported on at least one layer of interstitial ceramics material.
Claim 12
Dependent Claim
24 words
A trap according to claim 9 which comprises from 2 to 30 layers of the elongated elements interleaved by layers of interstitial ceramics material.
Claim 13
Dependent Claim
26 words
A trap according to claim 9 wherein each layer of interstitial ceramics material comprises intercrossing ceramics threads which define the interstices of the interstitial ceramics material.
Claim 14
Dependent Claim
14 words
A trap according to claim 11 wherein the threads make up a woven cloth.
Claim 15
Dependent Claim
20 words
A trap according to claim 9 wherein the open area of the interstitial ceramics material is from 20 to 60%.
Claim 16
Dependent Claim
48 words
A trap according to claim 13 wherein the ceramics material comprises at least one compound selected from the group consisting of the oxides, borides, carbides, silicides, nitrides and silicates of aluminum, zirconium, boron, silicon, magnesium, titanium, yttrium, beryllium, thorium, manganese, lanthanum, scandium, calcium, uranium, chromium, niobium and hafnium.
Claim 17
Dependent Claim
28 words
A trap according to claim 13 wherein the ceramics material is a composition comprising alumina, 0.1 to 30 wt % silica and 0 to 15 wt % boria.
Claim 18
Dependent Claim
12 words
A trap according to claim 13 wherein the ceramics material comprises zirconia.
Claim 19
Dependent Claim
17 words
A trap according to any one of claims 9 when enclosed within a heat-resistant metal gauze wrapping.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |