Process for the reduction of nitrogen oxides in an effluent

Claim 2

A process for the reduction of the concentration of nitrogen oxides in the effluent from the combustion of a carbonaceous fuel, the process comprises introducing a heterocyclic hydrocarbon selected from the group consisting of piperazine, piperidine, pyrazine, pyrazole, imidazole, oxazolidone, pyrrole and pyrrolidine into the effluent having an effluent temperature of greater than about 1200° F. under conditions effective to reduce the concentration of nitrogen oxides in the effluent.

Claim 3

The process of claim 1 wherein said heterocyclic hydrocarbon comprises piperazine.

Claim 4

The process of claim 1 wherein said heterocyclic hydrocarbon comprises piperidine.

Claim 5

The process of claim 1 wherein said heterocyclic hydrocarbon comprises pyrrole.

Claim 6

The process of claim 1 wherein said heterocyclic hydrocarbon comprises pyrrolidine.

Claim 7

The process of claim 1 wherein said heterocyclic hydrocarbon comprises pyrazole.

Claim 8

The process of claim 1 wherein said heterocyclic hydrocarbon comprises imidazole.

Claim 9

The process of claim 1 wherein said heterocyclic hydrocarbon comprises 2-oxazolidone.

Claim 10

The process of claim 1 wherein said heterocyclic hydrocarbon comprises pyrazine.

Claim 11

The process of claim 1 wherein the temperature of the effluent is greater than about 1300° F.

Claim 12

The process of claim 10 wherein the temperature of the effluent is greater than about 1450° F.

Claim 13

The process of claim 1 wherein the temperature of the effluent is below about 2000° F.

Claim 14

The process of claim 1 wherein said treatment agent is introduced into the effluent at a molar ratio of the nitrogen contained in said treatment agent to the baseline nitrogen oxides level of 1:5 to about 10:1.

Claim 15

The process of claim 13 wherein the molar ratio of treatment agent nitrogen to the baseline nitrogen oxides level is about 1:3 to about 5:1.

Claim 16

The process of claim 1 wherein said treatment agent is in solution, in a mixture or in a dispersion.

Claim 17

The process of claim 15 wherein said solution, mixture or dispersion comprises water.

Claim 18

The process of claim 1 wherein said treatment agent further comprises urea or ammonia.

Claim 19

The process of claim 15 wherein urea or ammonia is present in said solution, mixture or dispersion in an amount of about 2% to about 60% by weight.

Claim 20

The process of claim 15 wherein said heterocyclic hydrocarbon is present in said solution, mixture or dispersion in an amount of about 0.5% to about 25% by weight.

Claim 21

The process of claim 1 wherein the effluent comprises an excess of oxygen.

Claim 22

The process of claim 20 wherein said effluent has an excess of oxygen of no greater than about 12% by volume.

Claim 23

The process of claim 21 wherein said excess of oxygen in the effluent is about 1% to about 6% by volume.

Claim 24

A process for the reduction of the concentration of nitrogen oxides in the oxygen-rich effluent from the combustion of a carbonaceous fuel, the process comprising introducing a treatment agent which comprises urea or ammonis and further comprises a heterocyclic hydrocarbon selected from the group consisting of piperazine, piperidine, pyrazine, pyrazole, imidazole, oxazolidone, pyrrole and pyrrolidine into an effluent having a temperature greater than about 1200° F. under conditions effective to reduce the concentration of nitrogen oxides in the effluent.

Claim 25

A process for the reduction of the concentration of nitrogen oxides in the oxygen-rich effluent from the combustion of a carbonaceous fuel, the process comprising introducing a treatment agent which comprises urea or ammonis and further comprises a heterocyclic hydrocarbon selected from the group consisting of piperazine, piperidine, pyrazine, pyrazole, imidazole, oxazolidone, pyrrole and pyrrolidine into an effluent having a temperature greater than about 1200° F. under conditions effective to reduce the concentration of nitrogen oxides in the effluent.

Claim 26

The process of claim 23 wherein said heterocyclic hydrocarbon comprises piperazine.

Claim 27

The process of claim 23 wherein said heterocyclic hydrocarbon comprises piperidine.

Claim 28

The process of claim 23 wherein said heterocyclic hydrocarbon comprises pyrrole.

Claim 29

The process of claim 23 wherein said heterocyclic hydrocarbon comprises pyrrolidine.

Claim 30

The process of claim 23 wherein said heterocyclic hydrocarbon comprises pyrazole.

Claim 31

The process of claim 23 wherein said heterocyclic hydrocarbon comprises imidazole.

Claim 32

The process of claim 23 wherein said heterocyclic hydrocarbon comprises pyrazine.

Claim 33

The process of claim 23 wherein said heterocyclic hydrocarbon comprises 2-oxazolidone.

Claim 34

The process of claim 23 wherein the effluent is at a temperature of greater than about 1300° F.

Claim 35

The process of claim 32 wherein the effluent is at a temperature of greater than about 1450° F.

Claim 36

The process of claim 23 wherein said treatment agent is in solution, in a mixture or in a dispersion.

Claim 37

The process of claim 34 wherein said solution, mixture or dispersion comprises water.

Claim 38

The process of claim 35 wherein urea or ammonia is present in said solution, mixture or dispersion in an amount of about 2% to about 60% by weight.

Claim 39

The process of claim 36 wherein said heterocyclic hydrocarbon is present in said solution, mixture or dispersion in an amount of about 0.5% to about 25% by weight.

Claim 40

The process of claim 23 wherein said treatment agent is introduced into the effluent at a molar ratio of the nitrogen contained in said treatment agent to the baseline nitrogen oxides level of about 1:5 to about 10:1.

Claim 41

The process of claim 38 wherein the molar ratio of treatment agent nitrogen to baseline nitrogen oxides level is about 1:3 to about 5:1.

Claim 42

The process of claim 23 wherein said effluent has an excess of oxygen of no greater than about 12% by volume.

Claim 43

A process for the reduction of the concentration of nitrogen oxides in the oxygen-rich effluent from the combustion of a carbonaceous fuel, the process comprising introducing a treatment agent which comprises an aqueous solution, mixture or dispersion of about 2% to about 60% urea or ammonia by weight and about 0.5% to about 25% of a compound selected from the group consisting of piperazine, piperidine, pyridine, oxazolidone, pyrazole, imidazole, pyrazine, pyrrole and pyrrolidine by weight into an effluent having an excess of oxygen of about 1% to about 12% by volume and a temperature of about 1300° F. to about 2000° F. in an amount sufficient to provide a molar ratio of the nitrogen contained in said treatment agent to the baseline nitrogen oxides level of about 1:3 to about 5:1, under conditions effective to reduce the nitrogen oxides level in the effluent.

Claim 44

A process for the reduction of the concentration of nitrogen oxides in the oxygen-rich effluent from the combustion of a carbonaceous fuel, the process comprising introducing a treatment agent which comprises an aqueous solution, mixture or dispersion of about 2% to about 60% urea or ammonia by weight and about 0.5% to about 25% of a compound selected from the group consisting of piperazine, piperidine, pyridine, oxazolidone, pyrazole, imidazole, pyrazine, pyrrole and pyrrolidine by weight into an effluent having an excess of oxygen of about 1% to about 12% by volume and a temperature of about 1300° F. to about 2000° F. in an amount sufficient to provide a molar ratio of the nitrogen contained in said treatment agent to the baseline nitrogen oxides level of about 1:3 to about 5:1, under conditions effective to reduce the nitrogen oxides level in the effluent.

Claim 45

The process of claim 23 wherein the effluent is at a temperature below about 2000° F.