Co-axial injection system

1. A coaxial injection device for injecting and dispersing reagents into a reactor, comprising:

an exterior duct configured to inject high-velocity gas into the reactor to disperse the reagents into the reactor;

an outer-middle injector with at least one constricting orifice for liquid injection, the outer-middle injector being recessed relative to the exterior duct and having a cooling liquid water or cooling steam therein;

an inner-middle duct for low-velocity gas injection, the inner-middle duct being recessed relative to the outer-middle injector, wherein the inner-middle duct is in communication with a supply of cooling air, the supply of cooling air having a velocity less than the high-velocity gas of the exterior duct that is chosen to disperse reagents into the reactor; and

an interior injector with a constricting orifice for liquid injection, the interior injector having a liquid urea solution therein;

wherein, the exterior duct is formed by the internal wall of an insert and the external wall of the outer-middle injector; and is located externally to and circumferentially surrounds all other injectors and ducts; the outer-middle injector is formed by two concentric cylinders connected with an endplate, the endplate being substantially perpendicular to the two concentric cylinders and defining at least one injector orifice configured to inject reagents into the reactor; the inner-middle duct is formed by the interior wall of the outer-middle injector and the exterior wall of the interior injector; the interior injector is formed by a cylinder with the endplate being substantially perpendicular to the interior injector cylinder and defining the constricting orifice of the interior injector;

wherein the exterior duct injects high-velocity gas to disperse the reagents injected through the outer-middle injector, the inner-middle duct and the interior injector thereby ensuring the mixing and dispersion of the liquids and gases into the reactor to increase reaction homogeneity, reaction efficiency, reactor efficiency and reduced byproduct formation.

2. The device of claim 1 , wherein cooling steam is contained in the outer-middle injector.

3. A multiple coaxial injection device system comprising at least two coaxial injection devices of claim 1 and at least one reaction parameter probe; wherein,

the coaxial devices are located at spaced-apart locations along the reactor length and

the reaction parameter probe is located downstream of the injection devices.

4. The system according to claim 3 , wherein the parameter probe is a temperature probe and the injected fluids are high-velocity secondary air, cooling water, cooling air, and urea solution in the exterior duct, outer-middle injector, inner-middle duct, and interior injector, respectively, for the reduction of NOx in a combustion process.

5. The system of claim 3 , wherein the parameter probe is a temperature probe and the injected fluids are high-velocity secondary air, low quality steam, cooling air, and urea solution in the exterior duct, outer-middle injector, inner-middle duct, and interior injector, respectively, for the reduction of NOx in a combustion process.

6. A method for operating the system of claim 3 , comprising the steps of:

sampling a reaction parameter;

selecting at least one coaxial injection device best suited for injecting a secondary reagent, said at least one coaxial injection device comprising

an exterior duct configured for injecting high-velocity gas into the reactor to disperse the reagents into the reactor;,

an outer-middle injector with at least one constricting orifice configured for liquid injection into the reactor,

an inner-middle duct for low-velocity gas injection, and

an interior injector with a constricting orifice for liquid injection; wherein, the exterior duct is formed by the internal wall of an insert and the external wall of the outer-middle injector and is located externally to and circumferentially surrounds all other injectors and ducts,

the outer-middle injector is formed by two concentric cylinders connected with the endplate, the endplate defining the orifice,

the inner-middle duct is formed by interior wall of the outer-middle injector and the exterior wall of the interior injector; the interior injector is formed by a cylinder with an endplate, the endplate defining the orifice;

injecting a cooling liquid water or cooling steam through the outer-middle injector;

injecting the secondary reagent through the at least one selected coaxial injection device into a furnace having effluent prior to injecting; and

reacting the secondary reagent with the furnace effluent.

7. A method for reducing the NOx in a combustion effluent, comprising the steps of:

providing a system according to claim 3 ;

sampling the effluent temperature;

selecting at least one coaxial injection device best suited for injecting an NH3-generating reagent;

injecting the NH3-generating reagent through the at least one selected coaxial injection device.

8. The method of claim 7 , wherein the NH3-generating reagent is urea.

9. The method of claim 8 , wherein injected fluids are high-velocity secondary air, cooling water, cooling air, and urea solution in the exterior duct, outer-middle injector, inner-middle duct, and interior injector, respectively, for the reduction of NOx in a combustion process.