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US4303625A Expired / Lapsed US ⏱️ 0.0 years remaining

Treatment of reducing gas for suppression of corrosiveness

Assignee: ExxonMobil Technology and Engineering Co
•
Filing: 1978-02-21
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Granted: 1981-12-01
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Expires: 1998-02-21
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Abstract

Abstract The disclosed invention embodies both catalyst and process. The catalyst is comprised of a Group VIII metal, preferably a noble metal, especially platinum, or copper composited with a low acidity inorganic oxide base, preferably alumina. A bed of the catalyst is contacted at elevated temperature with nitrogen oxide containing gas at net reducing conditions to convert the nitrogen oxide to non-corrosive, innocuous by-products to render the gas useful for reservoir pressure maintenance injection needs. In all embodiments, the base with which the metal, or metals, is composited is one having an acidity ranging from about +6.8 to about +0.8 Ho (Hammet acid function), preferably from about +6.8 to about +1.5 Ho. Inorganic oxide bases, especially alumina, which exhibit a weakly acidic Hammet acidity function, Ho>/=+0.8, when impregnated with a noble metal, or copper, show a marked improvement in NOx removal vis-a-vis catalysts prepared by impregnating more strongly acidic aluminas with said metal species.

Inventors

  • 👤 Neville L. Cull

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 15:46
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/38; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J23/70

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 80 words
In a process wherein a fuel gas is burned with air to produce an exhaust gas which contains water vapor, carbon dioxide and nitrogen oxides which, when compressed, cooled, and condensed can form highly corrosive carbonic and nitric acids, the improvement comprising contacting said exhaust gas, at net reducing conditions, with a catalyst comprising a Group VIII metal or copper composited with an inorganic oxide base having a Hammet acidity function ranging from about +6.8 Ho to about +1.5 Ho.
Claim 2
Dependent Claim 80 words
In a process wherein a fuel gas is burned with air to produce an exhaust gas which contains water vapor, carbon dioxide and nitrogen oxides which, when compressed, cooled, and condensed can form highly corrosive carbonic and nitric acids, the improvement comprising contacting said exhaust gas, at net reducing conditions, with a catalyst comprising a Group VIII metal or copper composited with an inorganic oxide base having a Hammet acidity function ranging from about +6.8 Ho to about +1.5 Ho.
Claim 3
Dependent Claim 15 words
The process of claim 1 wherein the exhaust gas is formed by burning natural gas.
Claim 4
Dependent Claim 16 words
The process of claim 1 wherein the catalyst is one containing a Group VIII noble metal.
Claim 5
Dependent Claim 13 words
The process of claim 3 wherein the Group VIII noble metal is platinum.
Claim 6
Dependent Claim 22 words
The process of claim 1 wherein the Hammet acidity function of the base ranges from about +6.8 Ho to about +0.8 Ho.
Claim 7
Dependent Claim 12 words
The process of claim 1 wherein the inorganic oxide base is alumina.
Claim 8
Dependent Claim 10 words
The process of claim 6 wherein the base is ring-shaped.
Claim 9
Dependent Claim 12 words
The process of claim 6 wherein the base is shaped as half-rings.

References Cited (Backward Citations)

US1796501A Cited
US3328286A Cited
GB1024518A Cited
US3444256A Cited
US3801516A Cited
US3953576A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1984-11-30 1985-06-01 1985-12-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1988-11-30 1989-06-01 1989-12-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1992-11-30 1993-06-01 1993-12-01 $7700.00 Window Closed / Lapsed

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