Dual injection grid arrangement

Patent metadata

Field	Value
Publication number	US-2016279565-A1
Application number	US-201514670850-A
Country	US
Kind code	A1
Filing date	Mar 27, 2015
Priority date	Mar 27, 2015
Publication date	Sep 29, 2016
Grant date	—

Abstract

A furnace/boiler incorporates a dual injection grid arrangement as per present disclosure. The furnace includes an enclosure having burners projecting through walls of the lower half of the enclosure. The burners inject and ignite a supply of fuel and primary air. The combustion reaction takes place in a combustion chamber. The enclosure walls carry steam generating tubes which absorb radiative heat from the combustion flame to produce steam. The heat is also utilized by radiative/convective super-heater and reheater elements where steam flowing through the radiative/convective super-heater and reheater elements is superheated by the hot gas products of the combustion process. The hot gas combustion products are referred to as the exhaust or flue gas. The combustion products exit the combustion chamber at boiler nose and enter in the boiler/furnace area. The present grid arrangement inject chemicals to control the creating reactants particularly NOx and SO 3 emissions.

First claim

1 . A dual injection grid arrangement comprising at least one injection tube having at least one nozzle for injecting chemicals into a flow of flue gas, wherein the at least one injection tube extends generally transverse or axial to the flow of the flue gas, wherein the at least one nozzle of the at least one injection tube is an atomizing nozzle that injects chemicals in the flue gas in either a square or conical spray pattern.

2 . The dual injection grid arrangement of claim 1 , wherein, the at least one injection tube comprises an inner shell, which is surrounded by an outer shell.

3 . The dual injection grid arrangement of claim 1 , wherein, the injection can be a mixture of liquid/gas phase or liquid/liquid phase or gas/gas phase.

4 . The dual injection grid arrangement of claim 1 , wherein the chemicals comprising the mixture of ammonia or urea with an aqueous alkali or alkaline sorbent such as sodium carbonate, sodium bicarbonate or calcium hydroxide.

5 . The dual injection grid arrangement of claim 2 , wherein, the at least one nozzle is attached to the inner shell to inject a liquid alkali or alkaline sorbent or mixture of alkali or alkaline sorbent with or without ammonia and water into the flow of flue gas.

6 . The dual injection grid arrangement of claim 2 , wherein, at least one extension arm with at least one nozzle cap is attached in a staggered arrangement to the outer shell to inject gaseous ammonia diluted with air into the flow of flue gas.

7 . The dual injection grid arrangement of claim 2 , wherein, plurality of pores ( 100 ) can be formed in a staggered arrangement on the outer shell to provide cool air into the flow of flue gas.

8 . The dual injection grid arrangement of claim 1 , wherein, a controller for NOx and a controller for SO 3 are provided to control the flow of the chemicals through the dual injection grid arrangement.

9 . The dual injection grid arrangement of claim 8 , wherein, the controlled dual injection grid arrangement provides chemicals at the same time and location to control the SO 3 emission and the NOx emission in the flue gas.

10 . The dual injection grid arrangement of claim 1 , wherein, the injection of the chemicals covers full cross-sectional area of duct, eliminating the need for additional flue gas mixing devices, either upstream or downstream of the dual injection grid arrangement location.

11 . A method of reducing pollutants in the flue gas from a furnace comprising of
a dual injection grid arrangement with at least one injection tube having at least one nozzle; providing chemicals for reducing pollutants in the flue gas; supplying the chemicals to the dual injection grid arrangement; injecting the chemicals in the flue gas in either a square or conical spray pattern through the at least one nozzle, wherein the at least one nozzle is an atomized nozzle.

12 . The method of claim 10 , wherein, the supplying of chemicals includes the supplying of a mixture of ammonia or urea with an aqueous alkali or alkaline sorbent to an inner shell and an outer shell of the at least one injection tube.

13 . The method of claim 10 , wherein, the injecting of the chemicals includes the injecting a liquid alkali or alkaline based sorbent with or without ammonia and water into the flue gas through the at least one nozzle, which is attached to the inner shell.

14 . The method of claim 10 , wherein the injecting of the chemicals includes the injecting of gaseous ammonia with dilution air into the flue gas through at least one extension arm with at least one nozzle cap, which is attached in a staggered arrangement to the outer shell.

15 . The method of claim 10 , wherein,
controlling flow of the chemicals through the dual injection grid arrangement through an controller and controller; providing the chemicals at the same time and location to control the SO 3 and the NOx emissions in the flue gas.

16 . The method of claim 10 , wherein,
covering full cross-sectional area of a duct through the injection of the chemicals; eliminating the need for additional flue gas mixing devices either upstream or downstream of the injection grid arrangement location.

Assignees

• Alstom Technology Ltd

Inventors

• Cohen Mitchell B
• Hellewell Todd D

Classifications

• B01D2251/404

  of calcium · CPC title

• F23J2215/20

  Sulfur; Compounds thereof · CPC title

• F23J15/02

  of purifiers, e.g. for removing noxious material (traps for solid residues F23J3/04) · CPC title

• B01D2251/2067

  Urea · CPC title

• B01D53/76

  Gas phase processes, e.g. by using aerosols · CPC title