Aqueous ammonia injection scheme

Claim 2

A process for reducing the concentration of nitrogen oxides contained in combustion effluents, comprising (a) partially vaporizing an aqueous ammonia-containing solution in a separation zone to produce at least two streams; a first stream comprising ammonia rich vapor and a second stream comprising dilute aqueous ammonia; (b) mixing said first stream comprising ammonia rich vapor with a carrier gas; (c) injecting the mixture of ammonia rich vapor and carrier gas into a combustion effluent produced by a combustion zone; and (d) disposing of said second stream comprising dilute aqueous ammonia by either (i) injecting the second stream into the combustion effluent or (ii) utilizing the second stream in a scrubber or other plant unit.

Claim 3

The process of claim 1, wherein said dilute aqueous ammonia is injected into a combustion effluent at a different location from where the ammonia rich vapor is injected.

Claim 4

The process of claim 1, wherein said dilute aqueous ammonia is injected into and vaporized into a carrier gas and thereafter injected into the combustion effluent.

Claim 5

The process of claim 3, wherein the carrier gas is compressed air at an elevated temperature in the range of 400 to 500° F.

Claim 6

A process for reducing the concentration of nitrogen oxides contained in combustion effluents, comprising (a) partially vaporizing an aqueous ammonia-containing solution in a separation in a separation zone to produce at least two streams; a first stream comprising ammonia rich vapor and a second stream comprising dilute aqueous ammonia; (b) disposing of said second stream comprising dilute aqueous ammonia, by injecting said second stream into a carrier gas where it is vaporized to produce a dilute ammonia vapor stream; (c) combining said dilute ammonia vapor stream with said first stream, comprising ammonia rich vapor, to produce a combined ammonia vapor stream; and (d) injecting said combined ammonia vapor stream into a combustion effluent produced by a combustion zone.

Claim 7

A process for reducing the concentration of nitrogen oxides contained in combustion effluents, comprising (a) partially vaporizing an aqueous ammonia-containing solution in a separation in a separation zone to produce at least two streams; a first stream comprising ammonia rich vapor and a second stream comprising dilute aqueous ammonia; (b) disposing of said second stream comprising dilute aqueous ammonia, by injecting said second stream into a carrier gas where it is vaporized to produce a dilute ammonia vapor stream; (c) combining said dilute ammonia vapor stream with said first stream, comprising ammonia rich vapor, to produce a combined ammonia vapor stream; and (d) injecting said combined ammonia vapor stream into a combustion effluent produced by a combustion zone.

Claim 8

The process of claim 5, wherein the carrier gas is compressed air at an elevated temperature in the range of 400 to 500° F.

Claim 9

The process of claim 5 wherein a heating source for supplying heat to the separation zone is controlled by a pressure sensing controller, which senses the pressure int eh separation zone, such that a constant pressure is maintained in the separation zone to insure that the desired flow rate of the ammonia rich vapor out of the separation zone is accurately achieved.

Claim 10

The process of claim 7, wherein the flow rate of ammonia rich vapor is controlled in response to a demand signal and wherein the flow rate of said dilute aqueous ammonia stream is controlled by a temperature sensing controller such that the desired ammonia concentration int he liquid phase of the separation zone is maintained as a function of temperature and pressure.

Claim 11

A process for reducing the concentration of nitrogen oxides contained in a combustion effluent produced in a combustion zone, which process comprises: (a) partially vaporizing an aqueous ammonia-containing solution in a vaporizing zone to yield at least two streams: a first stream comprising ammonia rich vapor and a second or blow-down stream comprising dilute aqueous ammonia; (b) injecting the ammonia rich vapor into a combustion effluent at a first location in or about a combustion zone; (c) injecting the dilute aqueous ammonia, either vaporized or unvaporized, into the same combustion effluent; wherein the operating conditions in the vaporizing zone are controlled to provide the proper concentrations and quantities of ammonia in said first and second streams, according to which a heating source for the vaporizing zone is controlled by a pressure sensing controller, which senses the pressure in the vaporizing zone, such that a constant pressure in said vaporizing zone is maintained to insure that the desired flow rate and injection rate of said ammonia rich vapor injection is achieved, and wherein the flow rate of the ammonia rich vapor is controlled in response to a demand signal, and wherein the flow rate of said second or blow-down stream is controlled by a temperature sensing controller, which senses the temperature in said vaporizing zone, such that the desired ammonia concentration in the liquid phase of the vaporizer is maintained as a function of temperature and pressure.

Claim 12

A process for reducing the concentration of nitrogen oxides contained in a combustion effluent produced in a combustion zone, which process comprises: (a) partially vaporizing an aqueous ammonia-containing solution in a vaporizing zone to yield at least two streams: a first stream comprising ammonia rich vapor and a second or blow-down stream comprising dilute aqueous ammonia; (b) injecting the ammonia rich vapor into a combustion effluent at a first location in or about a combustion zone; (c) injecting the dilute aqueous ammonia, either vaporized or unvaporized, into the same combustion effluent; wherein the operating conditions in the vaporizing zone are controlled to provide the proper concentrations and quantities of ammonia in said first and second streams, according to which a heating source for the vaporizing zone is controlled by a pressure sensing controller, which senses the pressure in the vaporizing zone, such that a constant pressure in said vaporizing zone is maintained to insure that the desired flow rate and injection rate of said ammonia rich vapor injection is achieved, and wherein the flow rate of the ammonia rich vapor is controlled in response to a demand signal, and wherein the flow rate of said second or blow-down stream is controlled by a temperature sensing controller, which senses the temperature in said vaporizing zone, such that the desired ammonia concentration in the liquid phase of the vaporizer is maintained as a function of temperature and pressure.

Claim 13

The process of claim 9 wherein the ammonia rich vapor is mixed with a carrier gas prior to injection into the combustion zone.