US4722918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalyst for decreasing the content of nitrogen oxides in flue gases
Assignee: Sued Chemie AG
•
Filing: 1986-08-11
•
Granted: 1988-02-02
•
Expires: 2006-08-11
Abstract
Abstract A catalyst for decreasing the content of nitrogen oxides in flue gases. The catalyst contains at least one of the metals titanium, zirconium, vanadium, tungsten, molybdenum, or cerium in the form of one or more of their oxides combined with a silicate with a three-layer structure (three-layer silicate). The three-layer silicate is acid-activated while essentially retaining its crystalline layer structure. The three-layer silicate has a cation-exchange capacity of 30 mvals/100 g or more before acid activation. The acid activation lowers the concentration of interlayer cations and increases the BET surface at least 15% and preferably at least 50% in terms of the BET surface of the three-layer silicate before acid activation. The atomic ratio of the silicon in the acid-activated three-layer silicate to the metal in the oxide is from 0.2 and 50 and preferably from 0.4 to 25.
Inventors
- 👤 Michael Schneider
- 👤 Hans J. Wernicke
- 👤 Karl Kochloefl
- 👤 Gerd Maletz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:27
CPC Classifications
B; B01; B01J; B01J21/00; B01J21/16; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01J23/00; B01J23/16; B01J23/20; B01J23/22; B01J23/24; B01J23/28; B01J23/30; B01J35/00; B01J35/60; B01J35/64; B01J35/651
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
135 words
A catalyst for decreasing the content of nitrogen oxides in flue gases comprising at least one metal selected from the group consisting of titanium, zirconium, vanadium, tungsten, molybdenum and cerium in the form of one or more of their oxides and a clay mineral silicate with a three-layer structure having interlayer cations, the three-layer structure being acid-activated, while partly retaining its crystalline layer structure, the three-layer silicate having a cation-exchange capacity of 30 mvals/100 g or more before acid activation, the acid activation lowering the concentration of interlayer cations and increasing the BET surface area at least 15% in terms of the BET surface area of the three-layer silicate before acid activation, and the atomic ratio of the silicon in the acid-activated three-layer silicate to the metal in the oxide is from 0.2 and 50.
Claim 2
Dependent Claim
135 words
A catalyst for decreasing the content of nitrogen oxides in flue gases comprising at least one metal selected from the group consisting of titanium, zirconium, vanadium, tungsten, molybdenum and cerium in the form of one or more of their oxides and a clay mineral silicate with a three-layer structure having interlayer cations, the three-layer structure being acid-activated, while partly retaining its crystalline layer structure, the three-layer silicate having a cation-exchange capacity of 30 mvals/100 g or more before acid activation, the acid activation lowering the concentration of interlayer cations and increasing the BET surface area at least 15% in terms of the BET surface area of the three-layer silicate before acid activation, and the atomic ratio of the silicon in the acid-activated three-layer silicate to the metal in the oxide is from 0.2 and 50.
Claim 3
Dependent Claim
31 words
A catalyst according to claim 1, wherein the increase of the BET surface area is at least 50% of the BET surface area of the three layer silicate before acid activation.
Claim 4
Dependent Claim
29 words
A catalyst according to claim 1, wherein the atom ratio of the silicon in the acid-activated three-layer silicate to the metal in the oxide is from 0.4 to 25.
Claim 5
Dependent Claim
38 words
A catalyst according to claim 1, wherein the acid activation is such so as to decrease the concentration of interlayer cations in the catalyst at least 12% relative to their concentration in the three-layer silicate before acid activation.
Claim 6
Dependent Claim
22 words
A catalyst according to claim 1, wherein the interlayer cations are selected from the group consisting of sodium, potassium, magnesium and calcium.
Claim 7
Dependent Claim
27 words
A catalyst according to claim 1, wherein the SiO 2 content of the acid-activated three-layer silicate is at least 5% higher than that of the starting material.
Claim 8
Dependent Claim
27 words
A catalyst according to claim 1, wherein the SiO 2 content of the acid-activated three-layer silicate is at least 10% higher than that of the starting material.
Claim 9
Dependent Claim
30 words
A catalyst according to claim 1, wherein macropores with a diameter of more than 80 nm account for at least 25% of the total volume of pores of the catalyst.
Claim 10
Dependent Claim
62 words
A catalyst according to claim 1, wherein the metal oxides are individually present in the following ranges of concentration TiO 2 : 10-80% by weight, WO 3 and/or MoO 3 : 1-25% by weight, V 2 O 5 : 0.1-25% by weight, and CeO 2 : 1-25% by weight, with the acid-activated three-layer silicate accounting for the rest of the active constituents.
Claim 11
Dependent Claim
96 words
A catalyst according to claim 1, wherein when present in a binary combination, the metal oxides are present in one of the following percentages by weight: (a) (TiO 2 +V 2 O 5 ): 10-80, (b) (TiO 2 +WO 3 and/or MoO 3 ): 10-80, (c) (TiO 2 +CeO 2 ): 10-80, (d) (WO 3 and/or MoO 3 +V 2 O 5 ): 5-25, (e) (CeO 2 +V 2 O 5 ): 1-25, and (f) (ZrO 2 +V 2 O 5 ): 1-25, with the acid-activated three-layer silicate accounting for the rest of the active constituents.
Claim 12
Dependent Claim
69 words
A catalyst according to claim 10, wherein the ratios between the weights of the metal oxides are (a) V 2 O 5 :TiO 2 =0.001-0.2, (b) WO 3 and/or MoO 3 : TiO 2 =0.01-0.25, (c) CeO 2 :TiO 2 =0.1-0.3, (d) V 2 O 5 :WO 3 and/or MoO 3 =0.1-2.5, (e) V 2 O 5 :CeO 2 =0.1-1.0, and (f) V 2 O 5 :ZrO 2 =0.1-1.0.
Claim 13
Dependent Claim
104 words
A catalyst according to claim 1, wherein when present in a ternary combination, the metal oxides are present in one of the following percentages by weight: (a) (TiO 2 +WO 3 and/or MoO 3 +V 2 O 5 ): 10-80, (b) (TiO 2 +CeO 2 +V 2 O 5 ): 10-80, (c) (TiO 2 +ZrO 2 +V 2 O 5 ): 10-80, (d) (WO 3 and/or MoO 3 +CeO 2 +V 2 O 5 ): 10-25, and (e) (WO 3 and/or MoO 3 +ZrO 2 +V 2 O 5 ): 10-25, with the acid-activated three-layer silicate accounting for the rest of the active constituents.
Claim 14
Dependent Claim
104 words
A catalyst according to claim 12, wherein the ratios between the weights of the metal oxides present in the ternary combination are (a) WO 3 and/or MoO 3 : TiO 2 =0.01-0.25 V 2 O 5 :TiO 2 =0.01-0.11, (b) CeO 2 :TiO 2 =0.05-0.23, V 2 O 5 :TiO 2 =0.01-0.11, (c) ZrO 2 :TiO 2 =0.01-0.24 V 2 O 5 :TiO 2 =0.01-0.11, (d) CeO 2 :WO 3 and/or MoO 3 =0.1-5.0, V 2 O 5 :WO 3 and/or MoO 3 =0.1-2,5, and (e) V 2 O 5 :WO 3 and/or MoO 3 =0.1-2.5, ZrO 2 :WO 3 and/or MoO 3 =0.1-10.
Claim 15
Dependent Claim
28 words
A catalyst according to claim 1, wherein the catalyst is in the form of shaped bodies oblong or flat honeycombs, plates, rods, tubes, rings, wagon wheels or saddles.
Claim 16
Dependent Claim
38 words
A catalyst according to claim 1, wherein the catalyst is produced by impregnating the acid-activated three-layer silicate with a solution containing one or more of the metals in the form of salts and/or complex compounds and conducting calcination.
Claim 17
Dependent Claim
55 words
A catalyst according to claim 1, wherein the catalyst is produced by mechanically mixing the acid-activated three-layer silicate with an oxide or salt of one or more of the metals, impregnating the resultant mixture with a solution containing one or more of the metals in the form of salts and/or complex compounds, and conducting calcination.
Claim 18
Dependent Claim
44 words
A catalyst according to claim 1, wherein the catalyst is produced by precipitating or reprecipitating at least one compound containing one or more of the metals in the presence of a suspension of the acid-activated three-layer silicate, washing out the foreign ions, and calcining.
Claim 19
Dependent Claim
59 words
A catalyst according to claim 1, wherein the catalyst is produced by precipitating or reprecipitating at least one compound containing one or more of the metals in the presence of a mixture of suspensions of the acid-activated three-layer silicate and of an oxide or salt of one or more of the metals, washing out the foreign ions, and calcining.
References Cited (Backward Citations)
DE2458888A1
Cited
US3962135A
Cited
DE2410175A1
Cited
DE2748471A1
Cited
JPS5393193A
Cited
DE3438367A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |