High temperature ammonia scr catalyst and method of using the catalyst.

(54) Title: SELECTIVE CATALYTIC REDUCTION CATALYST FOR HIGH TEMPERATURE AMMONIA AND METHOD OF USE OF THE CATALYST.

(54) Title: HIGH TEMPERATURE AMMONIA SCR CATALYST AND METHOD OF USING THE CATALYST.

(57) Summary

A catalyst and method is provided for selectively reducing nitrogen oxides (NOx) with ammonia. The catalyst includes a first component comprising a zeolite or a mixture of zeolites, a second component comprising at least one member selected from the group consisting of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium , tantalum, osmium, barium, boron, calcium, strontium, potassium, vanadium, nickel, tungsten, an actinide, mixtures of actinides, a lanthanide, mixtures of lanthanides, and mixtures thereof, optionally an oxygen storage material and optionally an inorganic oxide. The catalyst selectively reduces nitrogen oxides to nitrogen with ammonia at high temperatures. The catalyst has a high hydrothermal stability. The catalyst has high activity for the conversion of low levels of nitrogen oxides into exhaust gas streams.

(57) Abstract

A catalyst and a method for selectively reducing nitrogen oxides ('NOx) with ammonia are provided. The catalyst ineludes a first component comprising a zeolite or mixture of zeolites selected from the group consisting of ZSM-5, ZSM-I I, ZSM-12, ZSM-18, ZSM-23, MCM-zeolites, mordenite, faujasite, ferrierite, zeolite beta, and mixtures thereof; a second component comprising at least one member selected from the group consisting of cerium, ¡ron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium, boron, calcium, strontium, potassium, vanadium , nickel, tungsten, an actinide, mixtures of actinides, a lanthanide, mixtures of lanthanides, and mixtures thereof; optionally an oxygen storage material and optionally an inorganic oxide. The catalyst selectively reduces nitrogen oxides to nitrogen with ammonia at high temperatures. The catalyst has high hydrothermal stability. The catalyst has high activity for conversion of low levels of nitrogen oxides in exhaust streams. The catalyst and the method may have special application to selective reduction of nitrogen oxides in exhaust gas from gas turbines and gas engines, although the catalyst and the method have broad application to a wide range of gas streams that have excess oxygen and high temperatures. The temperature of exhaust gas from gas turbines and gas engines is high. Both the high temperature and the low levels of inlet NOx are challenging for selective catalytic reduction (SCR) catalysts.

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PATENT TITLE NO. 342108 _SE_ ttCÜCTARh D (ICOMOmJa

Institute

Mexican Property

Industrial

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Owner (s): CATALYTIC SOLUTIONS, INC.

Address: 4567 Telephone Road, Suite 206, Ventura, California, 93003, USA

Name: SELECTIVE CATALYTIC REDUCTION CATALYST FOR HIGH TEMPERATURE AMMONIA AND METHOD OF USE OF THE CATALYST.

Classification: lnt.CI.8: B01D53 / 56; B01D53 / 58; B01J29 / 40; B01J29 / 42

Inventor (s): RAJASHEKHARAM MALYALA; SVETLANA IRETSKAYA; ERIC DEGUNS;

STEPHEN J. GOLDEN

REQUEST

Number: International filing date:

MX / a / 2013/001109 December 13, 2007

Divisional Patent Number: 313936

<td rowspan="2">Country:</td><td colspan="2">PRIORITY</td>

<td>Date:</td><td>Number:</td>

<td>US</td><td>January 9, 2007</td><td> 11/651,290</td>

<td>US</td><td>March 29, 2007</td><td> 11/731,570</td>

<td>Validity: Twenty years</td><td></td><td></td>

<td>Due date:</td><td>December 13, 2027</td><td></td>

The reference patent is granted based on articles 1, 2 fraction V, 6 useful fraction. and 59 of the Industrial Property Law.

In accordance with article 23 of the Industrial Property Law, this patent has a validity of twenty years: Non-expendable, counted from the date of filing of the international application and will be subject to payment of the 4th cake to maintain rights in force.

Whoever signs the present title, does so based on the provisions of the Wtfeulaa S® faeorónes HI and 7 ° bis 2 aje the Industrial Property Law (Official Gazette of the Federation (D OP) 27/09/1891. / 09/4894 10/25/1996, 12/26/1987, 05/17/1999, ¢ 06/01/2004, 06/16/2002 ^: 01/25/2 (j6, 05/06/2009, 01/06/2010, '8/89 / MKL W0 «^, ÍFjMOTl2 and 04/09/2012); articles f ·, 3 fraction V synciso a), 4 ° and 12 ° fraAones I Bill of the Regulations of the Instituto Mexicaro Ciela Industrial Property (DOF 14/12/1999, reformed the

07/28/2 «^ y« Ueulpe 4 °, 4 °, fraction V moso a), 16 fractions f and tUv se «JaffiBatuto Orgánico of the Mexican Institute of Indusíríaf Property (D OF 12/27/1999, amended erTOlD7Z002,2 &amp; fo7 / 26e47M / OÉraSJ4 and 09/13/2007); 1, 3 and 5 subsection a) of the Agreement that delegates powers to the Deputy Directors General, Coordinator, Divisional Directors, Holders of the Regional Offices, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the Mexican Institute of Industrial Property. (DOF 12/15/1999, amended on 02/04/2000. 07/29/2004, 08/04/2004 and 09/13/2007).

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Sand! No obu. Step 1.

Co!. Pueblo Santa Mana lepecan.

Xochimiícc. CP ioC¿0 Mexico City

Tei. (55; 53 34 07 00&gt; * n ρ_Λ

Issue Date: September 14, 2016

DIVISIONAL DIRECTOR OF PATENTS

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NAHANNY CANAL REYES

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MX / 2016Z74423

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FIELD OF THE INVENTION

The invention relates to a catalyst and a method for selective catalytic reduction of low levels of nitrogen oxides to ultra-low levels with ammonia at high temperatures.

BACKGROUND OF THE INVENTION

Nitrogen oxides are present in exhaust gases from stationary sources such as power plants, industrial processes, single-cycle and combined-cycle gas turbines, gas engines, and diesel engines. Emissions from these sources are subject to regulations in both the United States and

Europe. The laws that regulate emission standards have become stricter in recent years and will continue to become stricter in the future. Many countries require the removal of NO_X 90%. Modern gas turbines generally emit about 25 ppm NO_X, in this way the level of NO_X it needs to be reduced to about 2.5 ppm in order to comply with government regulations.

<img file="MX342108B_D0007.tif" />

Diesel engines normally operate in air-to-fuel ratios above

Emissions of nitrogen oxides and particulates from diesel powered vehicles can be significant.

Diesel vehicle emissions are also subject to regulations in both the United States and

Europe.

A method to withdraw NO_X Exhaust gas is contacting the exhaust gas stream with a reducing agent such as ammonia in the presence of a catalyst at elevated temperature. The catalyzed reaction of the reducing agent with NO_X it is referred to as selective catalytic reduction (SCR). Urea, ammonium hydroxide, ammonium formate, and other nitrogen-containing chemicals can also be used as a source of ammonia.

Exhaust gas temperature is very important in determining the type of catalyst that can be used because certain catalysts work (or work better) at certain temperature ranges. Exhaust gases from diesel engines are typically quite low, about 200 ° C, while exhaust gases from gas turbines and gas engines are typically in the range of about 300 ° C to about 700 ° C . In this way, used with diesel applications

<img file="MX342108B_D0008.tif" />

They probably do not work effectively when used with gas turbines or gas engines, and vice versa.

Traditional SCR catalysts for ammonia are based on vanadium pentoxide pentoxide (vanadia) / titanium dioxide (titania). Imanari et al. (US Patent No. 4,833,113), for example, describe an SCR catalyst comprising a titanium oxide, a tungsten oxide, and a vanadium pentoxide oxide. SCR catalysts for vanadium pentoxide / titanium dioxide ammonia normally operate at a temperature of approximately 250-370 ° C. Exhaust gas from light duty diesel powered vehicles is typically at a temperature of approximately 200 ° C or below. Vanadium pentoxide / titanium dioxide SCR catalysts have no significant activity at temperatures as low as 200 ° C or at high temperatures.

Byrne (US Patent No. 4,961,917, assigned to

Engelhard Corporation) discloses a method of passing ammonia, nitrogen oxides, and oxygen over zeolite catalysts promoted by iron or copper to selectively catalyze the reduction of nitrogen oxides. The new copper promoted catalyst has good activity. However it significantly deactivates the catalyst as it ages.

coppermade

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OF INDUSTRIAL PROPERTY

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Iron catalyst is much more stable than copper catalyst, it has maximum activity at about 350-500 ° C, significantly higher than the 200 ° C temperatures that occur in many diesel exhaust gas streams.

Furthermore, copper and iron catalysts have low activity at temperatures above 500 ° C, which frequently occurs with gas engines and gas turbines and are not very efficient in reducing NO._X.

Ito et al. (US Patent No.

5,900,222) describes a process for treating gases that contain NO_X at temperatures in the range 300-560 ° C using a cerium-containing zeolite catalyst and a reducing agent. The catalyst described by Ito was designed to be used mainly with diesel exhaust gases. Diesel engines generally emit much higher levels of NO_X than gas turbines and gas engines. Because the NOx conversion rate is generally a function of how much NO_X is present to be reduced, effective catalysts to reduce high amounts of N0_x cannot be effective in reducing low amounts of NO_X and vice versa.

Ichiki and collaborators (Publication of Request for

US Patent No. 2005/0159304) teach denitrification * sj catalysts for use at high: Jr. Go rrcp.rrn Mexican eg PROPERTY describe multiple catalysts. One contained a compound oxide consisting of titanium oxide and at least one of tungsten oxide, molybdenum oxide, and boron oxide. Another catalyst contains zirconium oxide and SO3 or SO₄¿~. The final catalyst described contains at least one of tungsten oxide, molybdenum oxide and boron oxide supported on a carrier comprising zirconium oxide and SO₃ bear₄^Z

Long-term data is not provided. Some of the disadvantages observed in some of the described catalysts include the use of sulfuric acid in the catalyst preparation and the possibility that these catalysts will not be active in the long term.

There is a need for ammonia SCR catalysts that are stable towards aging and that are active at high temperatures and that are effective in further reducing low N0 levels._x input.

SUMMARY OF THE INVENTION

The present invention is a catalyst and method for the selective reduction of nitrogen oxides in an ammonia gas stream by contacting the ammonia gas stream in the presence of the catalyst.

The catalyst contains a first component that eats a zeolite or mixture of selected zeolites' »consist of ZSM-5, ZSM-11, ZSM-12, ZSM-18, ZSM-23, zeolites

<img file="MX342108B_D0011.tif" />

MCM, mordenite, faujasite, ferrierite, beta zeolite and mixtures thereof; a second component selected from the group consisting of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium, boron, calcium, strontium, potassium, vanadium pentoxide, nickel, tungsten , an actinide, actinide mixtures, a lanthanide, lanthanide mixtures and mixtures thereof; optionally an oxygen storage material (OSM); and optionally an inorganic oxide. The catalyst of the invention has particular utility for use with high temperature exhaust gases in the range of about 300 ° C to about 700 ° C. It should be noted that the exhaust gas temperature refers to the temperature of the exhaust gas as it leaves the engine.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a graph showing the conversion rate of N0_x against temperature in degrees Centigrade, using a cerium mixed coating catalyst where the cerium load in the cerium mixed coating catalyst is 19

IMPI g / L. The graph shows five curves in forn ^_IT1^_Mf£ i &amp; rag&gt; a '

OF INDUSTRIAL PROPERTY

<img file="MX342108B_D0012.tif" />

various NO conditions_X input

<td>the</td><td>Figure 2 is</td><td>a</td><td>graph showing</td><td>the</td>

<td>percentage of</td><td>conversion of</td><td>NOT_X</td><td>against temperature</td><td>in</td>

<td colspan="3">degrees centigrade using</td><td>various catalysts</td><td>of</td>

<td>coating</td><td>mixed with</td><td colspan="2">cerium and a catalyst</td><td>of</td>

<td>coating</td><td>mixed no</td><td colspan="2">contains cerium;</td><td></td>

<td>The</td><td>Figure 3 is</td><td>a</td><td>graph showing</td><td>the</td>

<td>percentage of</td><td colspan="2">NO conversion_X and</td><td colspan="2">NH reduction₃ against</td>

the NH ratio₃/NOT_X using catalysts containing various amounts of cerium;

Figure 4 is a graph showing the percentage of NO conversion_X and NH reduction₃ against NH relationship₃/NOT_X using catalysts with various mixed coating charges;

Figure 5 is a graph showing the NO conversion_X against time in stream in hours to

500 ° C using a cerium mixed coating catalyst.

DETAILED DESCRIPTION OF THE INVENTION

Exhaust gas from motor vehicles and engines such as gas turbines contains nitrogen oxides. Nitrogen oxides in the exhaust gas can be removed by contacting the exhaust gas with agent

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MEXICAN INSTITUTE OF PROPERTY

INDUSTRIAL cone ammonia in the presence of a selective catalytic reduction (SCR) catalyst. Ammonia or another reducing agent reacts with nitrogen oxides to form nitrogen and water.

Water vapor in the exhaust gas can deactivate the SCR catalyst by decreasing the NO conversion._X. Therefore, the hydrothermal stability of the SCR catalyst is important.

Exhaust gas from light duty diesel engines is at low temperature, approximately

200 ° C. The low temperature activity of the SCR catalyst is therefore important for diesel engine applications. The exhaust gas from gas turbines and gas engines is at a high temperature, from about 300 ° C to about 700 ° C. The high temperature activity of the SCR catalyst is therefore important for gas engine and gas turbine applications. SCR catalysts according to the embodiments of the present invention have good conversion activity of

NOT_X at high temperatures.

According to Alcorn (US Patent No.

4,912,726), it is believed that the reduction of NO requires the presence of oxygen while the reduction of NO₂ does not require it

Alcorn also claims that the re

XMPX

MEXICAN INSTITUTE PE LA RROHF.OAD

INRUSTRIAL

<img file="MX342108B_D0015.tif" />

easier to carry out than NO reduction.

Alcorn indicates that the evidence appears to support a two-stage process for the SCR process for ammonia, where the following parallel reactions occur:

NO + 1/2 O₂-&gt; N0₂

<td></td><td>6 NO₂ t</td><td>8 NH3—&gt; 7</td><td>N₂ + 12 H₂0</td><td></td>

<td>How I know</td><td>shows</td><td>in the</td><td>examples later,</td><td>the</td>

<td>catalysts</td><td>SCR's</td><td>agreement</td><td>with the modalities of</td><td>the</td>

present invention have high activity at high temperatures with low levels of NO_X input. The SCR catalysts of the present invention remain active at high temperatures for extended periods of time.

The catalysts of the present invention comprise: a first component comprising a zeolite or mixture of zeolites selected from the group consisting of

ZSM-5, ZSM-11, ZSM-12, ZSM-18, ZSM-23, MCM zeolites, mordenite, faujasite, ferrierite, beta zeolite, and mixtures thereof; a second component selected from the group consisting of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium,

<img file="MX342108B_D0016.tif" />

boron, calcium, strontium, potassium, vanadium pentoxide, nickel, tungsten, an actinide, mixtures dq ^_s1

Ί nstítT

OF INDUSTRIAL PROPERTY

<img file="MX342108B_D0017.tif" />

lanthanide, lanthanide mixtures, and mixtures thereof; an oxygen storage material and optionally an inorganic oxide. Lanthanides are defined to mean

Y, La, Pr, Nd, Sm, Eu, Gd, Ho or Yb. Actinides are defined to mean Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm,

Md, No and Lr. The oxygen storage materials can generally be cerium oxide based materials as described in more detail below. The inorganic oxide can generally be alumina, silica, or titanium dioxide as described in more detail below.

The catalysts of the present invention offer benefits over the prior art. Some prior art patents, such as US Patent No. 5,900,222, are directed toward cerium-containing zeolite catalysts. The complete catalyst in the prior art is composed of a zeolite, which can be expensive. However, the catalyst of the present invention contains a first component comprising a zeolite or mixture of zeolites; a second component comprising a member selected from the group consisting of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium, boron, calcium, strontium, potassium,

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of actinides, a lanthanide,

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lantanade ^ w ^ ADmi mixtures thereof; optionally an oxygen storage material and optionally an inorganic oxide. The presence of these additional components eliminates the need for 100% zeolite while producing a high conversion rate resulting in a more cost-effective catalyst. While not wishing to be limited by theory, additional components are also believed to contribute to the ability of the catalyst to further reduce low NO levels._X input.

Furthermore, the catalysts of the present invention work well at high temperatures. Until now, there have been no useful high temperature SCR catalysts that were effective in reducing low NO levels._X input to ultra-low levels without significant deactivation at high temperatures for extended periods of time.

Current practice is to cool exhaust gases to a temperature where available catalysts are active. This cooling process is expensive, time consuming, and requires expensive equipment and space. The catalysts of the present invention solve this problem. There is no need for the extensive cooling process because the catalysts operate at high gas temperatures.^escape- IMPI

MEXICAN INSTITUTE

First Component of Piety

The catalysts according to the embodiments of the present invention comprise at least one zeolite. The zeolite can be selected from the group consisting of ZSM-5, beta zeolite, a zeolite of the ZSM type, a zeolite of the type

MCM, mordenite, faujasite, ferrierite and mixtures thereof. In one embodiment, the zeolite can be selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-18, ZSM-23, a MCM zeolite, beta zeolite, and mixtures thereof. In one embodiment, the first component may comprise a mixture of two or more zeolites, preferably ZSM-5 and beta zeolite.

In a further embodiment, the beta zeolite to ZSM-5 ratio is from about 1: to about

one. In another embodiment, the first component may comprise a mixture of mordenite and ZSM-5, preferably in a ratio of approximately 1: to approximately 1. In a further embodiment, the first component may comprise a mixture of faujasite and ZSM-5, preferably in a ratio of about 1: to about 1. Zeolites can be combined in various ratios.

The zeolite or mixture of zeolites can be in the H form, the Na form, the ammonium form, or mixtures thereof. The H form of the zeolite can be a preferred form of the zeolite or mixture of zeolites.

The term exchanged with protonic sites in the zeolite is replaced with the second

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I FrtTÍTnWMEXTCANO DE LA PROPIEDAD INDUSTRIAL

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component but the second excess component is washed with water. The terms dealt with and exchanged with are known to a person of experience in the field.

Treated with includes, but is not limited to, exchanged with or that the zeolite mixes with the second component and the proton sites in the zeolite are replaced with the second component, eg cerium and further that the zeolite is impurified with the second component. Zeolite can also be treated with the second component. The SIO2 / AI2O3 ratio of the zeolite may be in a range of from about 1 to about 500, more preferably about 10 to about 150, and much more preferably about 30 to about

70. Although not wishing to be limited by theory, it is believed that zeolites having a SIO2 / AI2O3 ratio greater than about 10 may be beneficial in increasing the hydrothermal stability of the catalysts. A relationship

YES2 / AI2O3 of about 40 may be a preferred ratio.

The catalyst may comprise from about 100 to 100 weight percent zeolite, more preferably from about 40 to about 80 weight percent zeolite, and much more IMPT

MEXICAN INSTITUTE. ,_n ,,,, [&gt; E PROPERTY approximately 50 weight percent zeolite. industrial

<img file="MX342108B_D0022.tif" />

Component Two

The second catalyst component according to the embodiments of the present invention may comprise at least one component selected from the group consisting of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium, boron, calcium, strontium, potassium, vanadium pentoxide, nickel, tungsten, an actinide, actinide mixtures, a lanthanide, lanthanide mixtures, and mixtures thereof preferably cerium.

The catalyst of the present invention may comprise from about 1 to about 30 weight percent of the second component, more preferably from about 5 to about 20 weight percent, where the weight percentage of the second component is calculated based on the total metal content relative to the total weight of the zeolite, the oxygen storage material and the inorganic oxide which may or may not be present.

The catalyst according to the embodiments of the present invention may also comprise a second strontium component in addition to, or as a partial replacement for, the selected second component of the cf.ri consisting of cerium, iron, copper, chromium, cobalt , molybdenum, tin, rhenium, tantalum, osmium, íeccionaao ae

IMPI

OF IA INBOSTXIA RXOPIFDAD

<img file="MX342108B_D0023.tif" />

barium, boron, calcium, strontium, potassium, vanadium pentoxide, nickel, tungsten, an actinide, actinide mixtures, a lanthanide, lanthanide mixtures, and mixtures thereof. Without intending to be bound by theory, it is believed that the strontium component can improve the rheology and tack of the catalyst.

If the catalyst according to the embodiments of the present invention comprises a second strontium component, the catalyst may comprise from about 35 to 35 weight percent of the second strontium component, more preferably from about 5 to about 25 percent by weight. weight of the second strontium component and much more preferably from about 8 to about 15 weight percent of the second strontium component, where the weight percentage of the second strontium component is based on the strontium metal.

Oxygen Storage Material

An oxygen storage material is an additional component of the catalyst of the present invention. Oxygen storage materials can generally comprise a material based on

<img file="MX342108B_D0024.tif" />

Oxygen storage materials oxygen from oxygen rich feed streams and provide oxygen to oxygen deficient feed streams. The oxygen storage material can also be a support for the second component.

In some embodiments of the present invention, the oxygen storage material is not required. In those embodiments, the catalyst may comprise a first component comprising a zeolite or mixture of zeolites selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-18, ZSM-23, zeolites MCM, mordenite, faujasite, ferrierite, beta zeolite and mixtures thereof; a second component selected from the group that. Consists of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium, boron, calcium, strontium, potassium, vanadium pentoxide, nickel, tungsten, an actinide, actinide mixtures , a lanthanide, mixtures of lanthanides and mixtures thereof and optionally an inorganic oxide. The catalyst can be used to further reduce low NO levels_X input, approximately ppm or less. In some embodiments of the present invention, the catalyst can be used to reduce the highest levels of N0_xthat is, above 50 ppm, at lower levels.

The total surface area of ​​the

GIVE INDUSTRIAL PROPERTY cerium oxide can generally decrease when cerium oxide based materials are heated to temperatures of 800 ° C or higher. One or more metal oxides can be added to the cerium oxide based material to decrease the degree of sintering of the cerium oxide based material during exposure to high temperatures. Preferred metal oxides that can be added to cerium oxide based materials can be, for example, one or more ZrO₂, A1₂OR₃, The₂OR₃, or other rare earth metal oxides. Rare earth metals are defined as scandium and yttrium and elements with atomic numbers 57 to 71. In one embodiment of the present invention, the oxygen storage material may be a cerium oxide based material having a composition with the Cei_ formula_toZr_toOR₂ or Cei-_c-dZr_cLandau₂, where Lan is at least one of Y, La, Pr, Nd, Sm, Eu, Gd, Ho or Yb or mixtures thereof, where it can be approximately 0

<td>about 1 and c can</td><td>be from</td><td>about 0</td><td>to</td>

<td>about 1 yd can</td><td>be from</td><td>about 0</td><td>to</td>

<td>about 1 but c + d ncj »</td><td>It does not matter</td><td>to approximately</td><td> 0.</td>

<td>In another modality, the</td><td>material</td><td>storage</td><td>of</td>

TMPF?

oxygen in the catalyst okay

INSTITUTO MEXICANO invention can have a formula of Ce₀.oí * “* = **** (CZLY), Ceo.24Zro.671 ^ 0.09O2 (CZL), Cen ^ Zr» (C7, C)

Ce0.24Zr0.67Nd0.09O2 (CZN). In a preferred embodiment of the present invention, the oxygen storage material is Ce0.24Zr0.66Lao.04Y0.06O2 (CZLY). In another preferred embodiment, the oxygen storage material is Ceo.68Zro.32O2 (CZO). Other oxygen storage materials may also be suitable.

If the catalyst according to the embodiments of the present invention comprises at least one oxygen storage material, the catalyst may comprise from about 10 to about 90 weight percent of oxygen storage material, preferably from about 20 to about 70 percent by weight of oxygen storage material, more preferably about 30 to about 60 weight percent oxygen storage material and much more preferably about 40 weight percent oxygen storage material. The weight percentage of the oxygen storage material is based on the oxides.

While not wishing to be bound by theory, it is believed that oxygen storage material can

<img file="MX342108B_D0025.tif" />

increase the performance of catalysts

MEXICAN INSTITUTE nt. IA FROFI «DAD C ·

INDUSTRIAL ** _ modalities of the present invention by improving the ability of the catalyst to oxidize NO to N0₂. The N0₂ can react more quickly with ammonia or other reducing agent than in

NOT. Increasing the ability of the catalyst to oxidize NO to

NOT₂ therefore it can enhance catalyst activity to catalyze selective NO reduction_X with ammonia. The oxygen storage material can also improve the rheology of the aqueous suspensions for the optional coating (described below) comprising the oxygen storage material.

Inorganic Oxides

The catalyst according to the present invention may also comprise at least one inorganic oxide selected from the group consisting of AI2O3, SiO₂, Uncle₂, ZrO₂,

SnO₂, solutions, compounds and mixtures thereof. Without limitation, alumina is an inorganic oxide for use in the catalyst in accordance with the embodiments of the present invention. One function of inorganic oxide is to disperse the first and second components and help facilitate bonding to a substrate. Inorganic oxides can be used, for example, as part of a coating, as described below. Inorganic oxides can be replaced by all or part of the component of the oxygen storage material. In one modality,

<img file="MX342108B_D0026.tif" />

INSTITUTO MEXICANO quantity of oxy-suspension storage material.

amount of inorganic oxide can be -3? -a- earoty · previously provided for the oxygen storage material alone. The other inorganic oxides may be substituted, in whole or in part, for the oxygen storage material, although the inorganic oxides may have a different function than the oxygen storage material. Inorganic oxides can improve the rheology of aqueous suspensions for the optional coating and increase the adhesion of the coating to a substrate, if the catalyst is to be coated on a monolith.

Conformal Catalyst

In one embodiment, the catalyst of the present invention can be molded into a suitable conformation such as a honeycomb, pellets or beads. In another embodiment, the catalyst can be extruded into extruded materials.

In one embodiment, the catalyst according to the embodiments of the present invention can be formed by milling or grinding at least one of: a first component comprising a zeolite or mixture of zeolites selected from the group consisting of ZSM-5, ZSM -11, ZSM-12, ZSM-18, ZSM-23, MCM zeolites, mordenite, faujasite, ferrierite, beta zeolite, and mixtures thereof; a second make up

<img file="MX342108B_D0027.tif" />

at least one selected group member^rT'J ^^ s^xF,'.^&lt;E + ^ hs'

INDUSTRIAL Cerium, Iron, Copper, Gallium, Manganese, Chromium, Cobalt, Molybdenum, Tin, Rhenium, Tantalum, Osmium, Barium, Boron, Calcium, Strontium, Potassium, Vanadium Pentoxide, Nickel, Tungsten, An Actinide, Actinide Blends, a lanthanide, mixtures of lanthanides, and mixtures thereof to form a paste. The oxygen storage material can also be ground or ground with any or all of the other components. The remaining components of the catalyst can be added by means of methods well known to those skilled in the art.

The paste can be extruded through a mold to form extruded materials. Extruded materials can be dried and calcined thereby forming the catalyst. Other ways to form shaped catalysts may also be suitable.

Catalyst composition

Advantageously, the catalyst according to the embodiments of the present invention can be combined with a substrate to form a catalyst composition. Accordingly, another aspect of the present invention provides a catalyst composition comprising:

(a) a substrate;

(b) a catalyst comprising:

a first component that you buy

<img file="MX342108B_D0028.tif" />

<img file="MX342108B_D0029.tif" />

l'OTOTWEXICANC • S THE PROPERTY

INDUSTRIAL mix of zeolites selected from the group consisting of

ZSM-5, ZSM-11, ZSM-12, ZSM-18, ZSM-23, MCM zeolites, mordenite, faujasite, ferrierite, beta zeolite, and mixtures thereof;

a second component comprising at least one member selected from the group consisting of cerium, iron, copper, gallium, manganese, chromium, cobalt, molybdenum, tin, rhenium, tantalum, osmium, barium, boron, calcium, strontium, potassium, pentoxide vanadium, nickel, tungsten, an actinide, actinide mixtures, a lanthanide, lanthanide mixtures, and mixtures thereof;

optionally an oxygen storage material;

and optionally an inorganic oxide.

The inorganic oxide can be part of a coating, or the inorganic oxide can be separated from the coating. In another embodiment, the inorganic oxide can be part of the coating.

Substrate

As used herein, a substrate can be any support structure known in the art to support catalysts. The substrate can be a

11 ^ 4rínil

<img file="MX342108B_D0030.tif" />

refractory material, a substrate of

MEXICAN INSTITUTE OF PROPERTY

INDUSTRIAL honeycomb structure, a porcelain substrate, a metal substrate, a ceramic foam, a crosslinked foam, or suitable combinations, where the substrate has a plurality of channels and the required porosity. Porosity is dependent on the substrate. Additionally, the number of channels can vary depending on the substrate used. The channels discovered in a monolith substrate are described in more detail below. The type and conformation of suitable substrates would be apparent to a person of ordinary experience in the field. In an embodiment of the present invention, the substrate may be in the form of beads or pellets. The beads or pellets can be formed from alumina, silica alumina, silica, titanium dioxide, mixtures thereof, or any suitable material. In one embodiment of the present invention, the substrate can be a honeycomb backing. The honeycomb holder can be a ceramic honeycomb holder or a metal honeycomb holder. The ceramic honeycomb support can be formed, for example, from sillimanite, zirconia, petalite, spodumene, magnesium silicates, mulite, alumina, cordierite (Mg₂To the₄YES50i₈), other alumina-silicate materials, silicon carbide, or combinations thereof. Other ceramic supports may also be suitable.

suitable.

trapezoidal,

If the stand is a pa stand

MEXICAN INSTITUTE,, _n , DF IA FR ', M (T'AO ^ wrs ^ · ^Λ Metal may be a base metal alloy of heat, particularly an alloy in which -ei-iron-is a substantial or major component. The metal support surface can be oxidized at elevated temperatures above about 1000 ° C to improve the corrosion resistance of the alloy by forming an oxide layer on the surface of the alloy. The oxide layer on the surface of the alloy can also increase the adhesion of a coating to the surface of the monolith support. Preferably, all substrate supports, whether metal or ceramic, offer a three-dimensional support structure.

In one embodiment of the present invention, the substrate can be a monolithic carrier having a plurality of thin, parallel flow passages that extend through the monolith. The ducts can be of any cross-sectional shape and size.

The ducts can be, for example, rectangular, square, sinusoidal, hexagonal, oval or circular, although other shapes are also suitable. The monolith can contain from about 9 to about 1200 or more gas inlet holes or conduits per square inch of cross section although less c can be used

<img file="MX342108B_D0031.tif" />

MEXICAN INSTITUTE OF THE PKOPlF.tAD

The substrate can also be which &lt;^ 3'i'3Y ''

<img file="MX342108B_D0032.tif" />

suitable for particles. Some ways ~~ süb'St tSTO '?

Suitable filters may include woven filters, particularly ceramic woven fiber filters, wire meshes, disk filters, ceramic honeycomb monoliths, ceramic or metal foams, wall flow filters, and other suitable filters. Wall flow filters are similar to honeycomb substrates for automotive exhaust gas catalysts. They may differ from honeycomb substrates that can be used to form normal automobile exhaust gas catalysts in that the wall flow filter channels can be alternately plugged at an inlet and outlet so that the exhaust gas is forced to flow through the porous walls of the wall flow filter while traveling from the inlet to the outlet of the wall flow filter.

Coating

In some embodiments, at least a portion of the catalyst of the present invention can be placed on the substrate in the form of a coating. The term "coating" as used herein, refers to a coating of solid oxides on the substrate or solid support structure. The solid oxides in the coating can be one or more ox

The

<img file="MX342108B_D0033.tif" />

MEXICAN INSTITUTE OF THE PPtWF.DAD carrier, one or more catalyst oxides or íjná^Tri me zcTáT ^ Se oxides of carrier material and oxides of '' catalyst. Carrier material oxides are porous solid oxides that can be used to provide a high surface area for a dispersed phase. Carrier materials are normally stable at high temperatures and under a range of reduction and oxidation conditions. The zeolite and the oxygen storage material can be solid oxides and each can be part or all of the coating.

The inorganic oxide can also be a solid oxide and can be part or all of the coating.

In one embodiment, a coating can be formed on the substrate by suspending the carrier materials in water to form an aqueous suspension and by laying (laying includes but is not limited to depositing, adhering, curing, coating, and any of the known coating processes for coating a film on a substrate) the aqueous suspension on the substrate as a coating.

Carrier materials in the suspension may comprise the zeolite or mixture of zeolites, or the zeolite (s) and the oxygen storage material. In one embodiment, the solid oxides comprising the coating may optionally comprise the zeolite (s) and / or the oxygen storage material. In another embodiment, it may further comprise at least one

<img file="MX342108B_D0034.tif" />

selected from the group consisting of alumina, silica, titanium dioxide, silica-alumina, and solid solutions, compounds, and mixtures thereof.

Other components such as salts of the second component can optionally be added to the aqueous suspension. Other components such as acid or base solutions or various salts or organic compounds can be added to the aqueous suspension to adjust the rheology of the suspension.

Some examples of compounds that can be used to adjust rheology include, but are not limited to, ammonium hydroxide, aluminum hydroxide, acetic acid, citric acid, tetraethylammonium hydroxide, other tetraalkylammonium salts, ammonium acetate, ammonium citrate , glycerol, commercial polymers such as polyethylene glycol and other suitable polymers.

In one embodiment, the second component can be added to the aqueous suspension as oxides or other compounds, for example nitrates, acetates, or other salts and / or mixtures thereof. The suspension can be placed on the substrate in any suitable way. For example, the substrate can be dipped into the suspension, or the suspension can be sprayed onto the substrate. Other methods for

IMPI

<img file="MX342108B_D0035.tif" />

deposit the suspension on the substra

MEXICAN INSTITUTE Γ&gt; Ε THE PROPERTY those persons skilled in the art can * use * the alternative modalities. If the substrate is a monolithic carrier with parallel flow ducts, the liner may form on the duct walls. The gas flowing through the flow conduits can contact the liner on the duct walls as well as the materials that are supported on the liner.

It is believed that the oxygen storage material can improve the rheology of the coating suspension. This improvement can be seen in the control and / or process manufacturing of the catalyst. The increased rheology of the coating suspension which may be due to the presence of the oxygen storage material can increase the adhesion of the coating suspension to the substrate.

In one embodiment of the present invention, a coating can be formed by depositing the zeolite and optionally the oxygen storage material on the substrate. The coating may also comprise at least one inorganic oxide selected from the group consisting of alumina, silica, titanium dioxide, silica-alumina, and solid solutions, compounds, and mixtures of

<img file="MX342108B_D0036.tif" />

the same. A solution that includes s * (7

OF THE INDUSTRIAL PROFIBILITY water soluble second component can be impregnated and / or exchanged within the coating after the coating is placed on the substrate. In an alternative embodiment, the salts of the second component can be added to the aqueous suspension for coating. In yet another embodiment, the second component can be added to the aqueous coating slurry as it oxidizes.

The substrate, the coating, and the impregnated or exchanged solution (comprising water soluble precursor salts of the second component) can be calcined to form the catalyst composition before or after the coating and / or solution is added to the substrate.

In one embodiment, the coating and the impregnated or exchanged solution can be dried prior to calcination.

Withdrawal Method NO_X

The exhaust gas can be contacted with the catalyst according to the embodiments of the present invention in the presence of sufficient ammonia to reduce NO_X which is contained in the exhaust gas. Ammonia can normally be introduced into the exhaust gas before the exhaust gas makes contact with the catalyst according to an embodiment of the present invention. Exhaust gas can be _posited in deNsr &amp; erb aExicastn .Vpépst;

Ammonium formate, suitable for ammonia and ammonia as a reducing agent contact with the catalyst, reducing nitrogen oxides in the exhaust gas.

Urea, ammonium hydroxide, ammonia gas, or any other source can be used as a source of ammonia.

The ammonia / NO molar ratio_x it may be in a range of about 0.5 to about 4, more preferably in a range of about 0.6 to about 2, and much more preferably in a range of about 0.8 to about 1.5. Low ammonia / NO ratios_x may be generally preferred in order to

<td>minimize</td><td>the</td><td>ammonia</td><td>excess gas</td><td>exhaust.</td><td>The</td>

<td>ammonia</td><td>of</td><td>excess in</td><td>exhaust gas can</td><td colspan="2">be undesirable</td>

<td>because</td><td>the</td><td>problems</td><td>health or odor.</td><td></td><td></td>

<td></td><td>The</td><td>space</td><td>gas velocity of</td><td>escape and</td><td>the</td>

<td>ammonia</td><td>than</td><td colspan="3">pass through the catalyst can be on</td><td>a</td>

approximately 1,000 hr interval¹ at approximately 150,000 hr^-1, more preferably in an interval of about 5,000 hr¹ at approximately 100,000 hr¹ and much more preferably in an interval of about 10,000 hr ¹ at approximately 60,000 hr¹.

The exhaust gas and ammonia can be brought into contact with the catalyst at a temperature of

<img file="MX342108B_D0037.tif" />

about 300 ° C at about

INSTITUTO MEXICANO preferably at a temperature of approximately^rteB »A'3 about 600 ° C and much more pref cu ^ He-l-ement-e-a-Lhiá '·” temperature from about 450 ° C to about 600 ° C.

If excess ammonia is present in the exhaust gas, at least a portion of the excess ammonia can be oxidized to nitrogen by the catalyst in accordance with the embodiments of the present invention.

<td></td><td>The</td><td colspan="2">following examples are</td><td>they propose for</td><td>to illustrate,</td>

<td>but no</td><td>for</td><td>limit</td><td>, the scope of</td><td>the invention.</td><td>Must be</td>

<td>understand</td><td>than</td><td>others</td><td>procedures</td><td>known for</td><td>those</td>

<td>people</td><td colspan="2">experts</td><td>in the technique</td><td>can be</td><td>use</td>

alternatively.

EXAMPLES

Example 1

Preparation of the Coating Catalyst Mixed with

Cerium

A cerium mixed coating catalyst (Catalyst 1) was prepared as follows. An aqueous suspension of mixed coating was formed. The mixed coating contained approximately 10% alumina, 50% mixed zeolites and Ce₀.24Zr₀.₆₆The₀.04Yo.o602 at 40%. The mixed zeolites were H-ZSM-5 and H-beta in a weight ratio of

50:50.

All percentages are in

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OF THE PROPERTY · INDUSTRIAL

<img file="MX342108B_D0038.tif" />

indicate otherwise.

The suspension was ground in a ball mill to a particle size (d₅o) of approximately 4-5μ, The suspension was placed on a monolith substrate of 400 cells per square centimeter (per square inch) such that the monolith wall ducts were coated with the coating at a load of approximately 160 g / L . The coated monolith was placed under the light to confirm that the channels were not covered by the mixed coating suspension. If there were clogged or obstructed channels, they were cleared by blowing air using an air knife. The coated substrate was dried by blowing air through the open channels at room temperature for about 10 to 15 hours. The dry coated substrate was calcined in a static air oven at approximately 550 ° C for approximately 4 hours.

The calcined substrate was cooled to room temperature and the water uptake of the coated substrate was determined. The cerium nitrate solution sufficient to form a cerium-containing mixed coating catalyst with a cerium metal charge of 19 g / L of the catalyst was dissolved in an amount of distilled water equal to the water uptake of the coated substrate.

This cerium nitrate solution is imp

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OF INDUSTRIAL PROPERTY

<img file="MX342108B_D0039.tif" />

on the coated substrate. The monolith impregnated with the cerium nitrate solution was placed under the light to confirm that there were no channels covered by the cerium nitrate impregnation solution. If there were clogged, obstructed, or absorbed channels, they were cleared by blowing air using an air knife. The substrate was dried by blowing air through the channels at room temperature for about 10 to 15 hours. The substrate was calcined at about 550 ° C for about 1 hour.

A similar procedure was used to obtain cerium mixed coating catalysts with cerium loads of 5 g / L, 10 g / L, 22 g / L, 30 g / L and 40 g / L.

The cerium catalyst with a cerium charge of g / L and a mixed coating charge of about

160 g / L was tested in the temperature range of

300 ° C to 700 ° C in various NO conditions_X input using NH3 / NO ratio_X 1 and at a space speed ge''15,000 hr¹'. The results are shown in Figure 1.

The results indicate that the performance of the cerium-containing catalyst depends on the test conditions, especially on the amount of NO_X Present that it needs to be removed, particularly at high temperatures.

For example, at a temperature of 550 ° C, Je Jg &lt;

MEXICAN PROPERTY INSTm / TO tests a feed gas containing 5 ppm of Wy l¿i removal efficiency of N0_x was around 60% whereas, using the same catalyst with a feed gas containing 50 ppm N0_x at a temperature of 550 ° C, the removal efficiency of NO_X observed was around 90%.

Example 2

Preparation of the Coating Catalyst Mixed with

Cerium

A cerium mixed coating catalyst (Catalyst 2) was prepared as follows. A cerium-containing mixed coating aqueous suspension was formed. Alumina powders 10%, zeolites mixed with

50% and 40% Ce0.24Zr0.66La0.04Y0.06O2 were mixed with a solution containing cerium nitrate and water. The mixed zeolites were H-ZSM-5 and H-beta in a weight ratio of

50:50. Sufficient cerium nitrate solution was used to result in 22 g / L cerium in the final catalyst.

<td></td><td>The</td><td colspan="2">suspension was ground</td><td>in a mill</td><td>balls to a</td>

<td>size</td><td>of</td><td>particle (d₅₀)</td><td>of</td><td>approximately</td><td>4-5μ. The</td>

<td colspan="2">suspension</td><td>was placed on</td><td>a</td><td colspan="2">400 monolith substrate</td>

<td>cells</td><td>by</td><td>square inch</td><td colspan="2">(62.5 cells per</td><td>centimeter</td>

square) such that the monolith wall ducts were coated with the mixed coating

<img file="MX342108B_D0040.tif" />

at a load of approximately ISO q / L^PI ms.jsSEFgy coated was placed under the light to confirm that there were no channels plugged by the mixed coating suspension.

If there were clogged or obstructed channels, they were cleared by blowing air using an air knife. The cerium containing mixed coating substrate was dried by blowing air through the open channels at room temperature for about 10 to 15 hours. The dry coated substrate was calcined in a static air furnace of approximately 550 ° C for approximately 4 hours.

The calcined substrate was cooled to room temperature to obtain 22 g / L of a cerro-containing mixed coating catalyst (Catalyst 2).

Example 3

Preparation of the No Mixed Coating Catalyst

Contains Cerium

A cerium-free catalyst was prepared according to the procedure described in Example 2 except that a cerium nitrate solution was not added to the powder mixture. The suspension was formed by mixing the powders described in Example 2 with water. The mixed coating load on the final catalyst was approximately

160 g / L.

<img file="MX342108B_D0041.tif" />

Example 4

Catalyst Preparation

Zeolite from

A1 Powders₂OR₃ and Ce0.24Zr0.66La0.04Y0.06O2 were combined in a 50:50 ratio. A suspension was prepared by combining this mixture with water and a cerium nitrate solution. Sufficient cerium nitrate solution was used to result in 22 g / L cerium in the final catalyst. The suspension was coated onto a substrate of 400 cells per square inch (62.5 cells per square centimeter) and a final catalyst was obtained following the procedure described in Example 2. The mixed coating load on the final catalyst was approximately 160 g / L with a cerium load of 22 g / L (Catalyst 3).

Example 5

Performance of Various Mixed Coating Catalysts

The cerium-containing mixed coating catalysts prepared according to Examples 1, 2 and and the non-cerium-containing mixed coating catalyst prepared according to Example 3 were tested for NO reduction activity_X in the temperature range of 300 to 700 ° C using 50 ppm NO_X input and 50 ppm NH₃. Comparable tests were conducted at a space velocity of

<img file="MX342108B_D0042.tif" />

Results are plotted on a graph in 2? ** Results indicate that indepvtiditílltéménré W as cerium is introduced into the mixed coating, the level of NOx conversion, especially at higher temperatures, remains the same. Figure 2 also shows that cerium is required in the mixed coating to achieve good performance in the 300-500 ° C temperature range.

NO conversions were observed_X negative when the test was performed using the catalyst described in Example

Four. The reason for this is because this catalyst was not only inactive for NO conversion_X a N₂ using

NH₃but also oxidized the NH₃ year_X consequently increasing the content of NO_X total post-catalyst gas composition when compared to feed composition before catalyst.

Example 6

Performance of Samples Containing Variant Loads of

Cerium on Mixed Coating

Catalyst samples with various cerium fillers were prepared as described in Example 1 and tested for NO conversion activity_X in various NH relationships₃/NOT_X. Figure 3 shows a NO conversion graph_X on the primary Y axis and a reduction of NH₃ on the secondary Y axis against the ratio

<img file="MX342108B_D0043.tif" />

OF INDUSTRIAL PROPERTY

<img file="MX342108B_D0044.tif" />

The NH relationship₃/NOT_X it was varied from 0.8 to 1.2. All catalyst samples with various cerium charges resulted in very high NO conversion_X under test conditions. Mixed coating catalysts containing various cerium fillers also resulted in a reduction of NH₃ very low.

Example 7

Sample Performance With Variable Loads

Mixed Coating

The catalyst samples were prepared according to the procedure described in Example 2 with various coating loads using a mixed coating that already contains cerium. Samples contained mixed coating loads of 75.1 g / L, 90.2 g / L, 127.8 g / L, 142.5 g / L, and 164 g / L. Catalyst samples were tested for NO conversion activity_X in various NH relationships₃/NOT_X. Figure 4 shows a graph of the NO conversion_X on the primary Y axis and reducing

NH₃ on the secondary Y axis against the NH ratio₃/NOT_X on the X axis. The NH relation₃/NOT_X it was varied from 0.8 to 1.2. The results suggest that an optimal coating load of 160g / L is necessary to achieve good N0 conversion._x and a reduction in NH₃ low in various test conditions.

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

<img file="MX342108B_D0045.tif" />

Example 8

Long Term Activity Test

Using the sample of catalizadai_de ^ £ xil-a_ea-jeJ.

Example 1, a test was conducted at 500 ° C using feed gas containing 50 ppm N0_x, 50 ppm NH3, 15% of

OR₂, 10% H₂Or, 5% CO₂ and the rest as N₂. The test was conducted without interruption for 100 hours and data was collected every 15 minutes. Figure 5 shows a NO conversion graph_X against time in stream in hours. The results indicate that there was no significant catalyst deactivation observed at

500 ° C.

The catalysts according to the embodiments of the present invention have high conversion activity of

NOT_X at high temperatures and are able to further reduce low NO levels_X input. Furthermore, the catalysts according to the embodiments of the present invention also have high hydrothermal stability.

Catalysts in accordance with the embodiments of the present invention may have applications for gas streams having excess oxygen and having a temperature in the range of about 300 ° C to about 700 ° C. Some examples of applications include, but are not limited to, gas turbine exhaust gas, exhaust gas from engine exhaust plants of power generation plants,

<img file="MX342108B_D0046.tif" />

chemical and other suitable applications.

The present invention can be incorporated in other specific forms without departing from its essential characteristics. The described modality should be considered in all aspects only as illustrative and not as restrictive. The scope of the present invention, therefore, is indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims must be included within their scope.

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<img file="MX342108B_D0047.tif" />