Claims
- 1. A process for producing a catalyst for denitrating by catalytic reduction using ammonia an exhaust gas discharged from an ash-circulating boiler system in which heavy metal compounds are concentrated, the process comprising the steps of:
- mixing and kneading titanic acid or titanium oxide with a compound of metal selected from the group consisting of V, Cu, Fe and Mn in a water medium to form a resulting paste;
- drying said resulting paste;
- calcining said resulting paste to obtain a calcined material;
- grinding said calcined material to obtain a catalyst powder; and
- contacting said catalyst powder with vapor of a molybdenum compound, tungsten compound or tin compound to adsorb said compound on the catalyst powder.
- 2. A process for producing a catalyst for denitrating by catalytic reduction using ammonia an exhaust gas, according to claim 1, wherein said step of contacting is carried out so that said compound is adsorbed on said catalyst powder at a density of 2.times.10.sup.-6 to 20.times.10.sup.-6 mol/m.sup.2 of surface area of said catalyst powder.
- 3. A process for producing a catalyst for denitrating by catalytic reduction using ammonia an exhaust gas according to claim 1, wherein the tungsten compound is tungsten oxide.
- 4. A process for producing a catalyst for denitrating an exhaust gas according to claim 1, wherein the tin compound is tin oxide.
- 5. A process for producing a catalyst for denitrating an exhaust gas according to claim 1, wherein the molybdenum compound is molybdenum oxide.
- 6. A process for producing a catalyst for denitrating by catalytic reduction using ammonia an exhaust gas according to claim 1, further comprising the steps of:
- applying a paste of said catalyst powder onto a substrate to obtain a resulting catalyst; and
- drying and calcining said resulting catalyst.
- 7. A process for producing a catalyst for denitrating by catalytic reduction using ammonia an exhaust gas discharged from an ash-circulating boiler system in which heavy metal compounds are concentrated, the process comprising the steps of:
- mixing and kneading titanic acid or titanium oxide with a compound of metal selected from the group consisting of V, Cu, Fe and Mn in a water medium to form a resulting paste;
- drying said resulting paste;
- calcining said resulting paste to obtain a calcined material;
- grinding said calcined material to obtain a catalyst powder;
- mixing and kneading said catalyst powder with a molybdenum compound to coat physically the surface of the powder with said molybdenum compound;
- applying a paste of said catalyst powder coated with said molybdenum compound onto a substrate to obtain a catalyst; and
- drying and calcining said catalyst.
- 8. A process for producing a catalyst for denitrating by catalytic reduction using ammonia an exhaust gas according to claim 7, wherein said catalyst powder is mixed and kneaded with an addition of fibrous materials.
Parent Case Info
This is a continuation of copending Ser. No. 201,536 filed June 2, 1988, now U.S. Pat. No. 4,966,882.
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Continuations (1)
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Number |
Date |
Country |
Parent |
201536 |
Jun 1988 |
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