High temperature catalyst and process for selective catalytic reduction of NO

1. A process of selective catalytic reduction of NOx in a combustion exhaust stream comprising:

preparing a catalyst by the steps of

a) steam treating a zeolite material at about 500° C.-600° C. for about 5-15 hours;

b) adding iron to the zeolite material at a loading between 0.01% and 10% iron;

and

c) calcining the zeolite material at about 750° C.-900° C. for about 1-5 hours;

wherein the order of steps a) and b) may vary, followed by step c);

mixing 60-82 ppm of ammonia into a combustion exhaust stream at over 500° C.;

contacting the combustion exhaust stream at 500° C.-650° C. with the catalyst in a manner necessary to facilitate a reaction between NO and NO 2 in the exhaust stream and the ammonia.

2. A process for preparing a catalyst for reduction of NOx in combustion exhaust, comprising:

a) steam treating a zeolite material at about 500° C.-600° C. for about 5-15 hours in air with about 10-25% water vapor;

b) adding iron to the zeolite material at a loading between 0.01% and 10% iron; and

c) calcining the zeolite material at about 500° C.-1100° C.;

wherein the order of steps a) and b) may vary, followed by step c).

3. The process of claim 2 , wherein said calcining performed at 800° C.-900° C. for 1-5 hours.

4. The process of claim 2 , comprising at least two calcining steps, at least one of which being performed in the range of 750° C.-900° C. for about 1-5 hours, and at least a final one of which being performed after the iron adding step.

5. The process of claim 2 , further comprising adding tungsten and/or phosphorus to the zeolite material prior to the calcining step.

6. The process of claim 2 , wherein the steam treating is performed at about with about 10-25% water vapor, and the calcining is performed at about 750° C.-900° C. in air with less than about 2% water vapor for about 1-5 hours.

7. The process of claim 2 , further comprising:

mixing the catalyst prepared according to claim 1 with a liquid to form a slurry;

washcoating a catalytic converter bed form with the slurry; and

calcining the washcoated bed form to make a catalyst bed for a catalytic converter apparatus.

8. A process for preparing a catalyst for reduction of NOx in combustion exhaust, comprising:

a) adding iron to an alumino-silicate zeolite material;

b) steam treating the zeolite material at a temperature of 500° C.-600° C. for about 5-15 hours in air with about 10-25% water vapor such that said steam treating is sufficient for partial de-alumination of the zeolite material to approximately a steady state, but not sufficient to fully collapse the chemical structure of the zeolite material;

c) calcining the zeolite material at a temperature, humidity, and duration sufficient to stabilize the zeolite material; and

wherein the order of steps a) and b) may vary, followed by step c)

whereby the process creates a stable and efficient catalyst for converting NO to N2 and H2 0 in combustion exhaust at temperatures from 300° C. to over 700° C.

9. The process of claim 8 wherein said calcining is performed at 800° C.-900° C. for about 1-5 hours.

10. The process of claim 8 , comprising:

steam treating a zeolite beta material at about 525° C. for about 5 hours;

calcining the zeolite beta material at about 825° C. for about 2 hours;

mixing the zeolite beta with iron (III) nonahydrate in water to form a slurry;

after about 1 hour, mixing zirconium acetate into the slurry;

washcoating a catalytic bed form with the slurry; and

calcining the washcoated catalytic bed form at about 525° C. for about 1 hour, forming a catalyst bed.

11. The process of claim 8 , comprising:

steam treating a zeolite beta material at about 525° C. for about 5 hours;

mixing the zeolite beta material with iron (III) nonahydrate in water to form a first slurry;

heating the first slurry to about 90° C.;

after about 3 hours, calcining the first slurry at about 825° C. for about 2 hours to form an iron-containing zeolite material.

12. The process of claim 11 , further comprising:

mixing the iron-containing zeolite material with zirconium acetate in water to form a second slurry;

washcoating a catalytic bed form with the second slurry; and

calcining the washcoated catalytic bed form at about 525° C. for about 1 hour, forming a catalyst bed.

13. The process of claim 8 , comprising:

mixing a zeolite beta material with lanthanum nitrate nonahydrate in water to form a first slurry;

heating the first slurry to about 95° C. for about 6 hours;

mixing the resulting zeolite material with iron (III) nonahydrate in water to form a second slurry;

heating the second slurry to about 90° C. for about 2 hours;

steam treating the resulting zeolite material at about 500° C. for about 14 hours;

calcining the resulting zeolite material at about 825° C. for about 2 hours to form a lanthanum zeolite beta material.

14. The process of claim 13 , comprising:

mixing the lanthanum zeolite beta material and additional iron (III) nitrate nonahydrate with water to form a third slurry;

heating the third slurry to about 90° C.;

after about 3 hours, steam treating the resulting zeolite material at about 525° C. for about 5 hours; and

calcining the resulting zeolite material at about 825° C. for about 2 hours to form an iron-lanthanum-containing zeolite material.

15. The process of claim 14 , further comprising:

mixing the iron-lanthanum-containing zeolite material with zirconium acetate in water to form a fourth slurry;

washcoating a catalytic bed form with the fourth slurry; and

calcining the washcoated catalytic bed form at about 525° C. for about 1 hour, forming a catalyst bed.

16. The process of claim 8 , comprising:

steam treating a pre-calcined zeolite beta material at about 525° C. for about 5 hours;

mixing the resulting zeolite material with iron (III) nonahydrate and ammonia metatungstate in water to form a first slurry;

heating the first slurry to about 90° C. for about 3 hours; and

calcining the resulting zeolite material at about 825° C. for about 2 hours to form an iron-tungsten-containing zeolite material.

17. The process of claim 16 , further comprising:

mixing the iron-tungsten-containing zeolite material with zirconium acetate in water to form a second slurry;

washcoating a catalytic bed form with the second slurry; and

calcining the washcoated catalytic bed form at about 525° C. for about 1 hour, forming a catalyst bed.

18. The process of claim 8 , comprising:

steam treating a zeolite beta material at about 525° C. for about 5 hours;

mixing the zeolite beta material with iron (III) nonahydrate and ammonium phosphate in water to form a first slurry;

heating the first slurry to about 90° C. for about 3 hours;

calcining the resulting zeolite material at about 825° C. for about 2 hours to form an iron-phosphorus-containing zeolite material.

19. The process of claim 18 , further comprising:

mixing the iron-phosphorus-containing zeolite material with zirconium acetate in water to form a second slurry;

washcoating a catalytic bed form with the second slurry; and

calcining the washcoated catalytic bed form at about 525° C. for about 1 hour, forming a catalyst bed.