Oxidation control for improved flue gas desulfurization performance

1. A system for controlling oxidation of sulfites in a slurry, comprising:

a tank having an inlet for receiving a slurry and an inlet for receiving a gas, the inlet for receiving the gas configured so that at least a portion of the gas received in the tank is dispersed through at least a portion of the slurry received in the tank;

a sulfite concentration measuring sensor arranged in contact with the slurry received in the tank to real time measure a sulfite concentration S 1 of the slurry received in the tank to obtain a real time sulfite concentration S 1 measurement transmitted by the sulfite concentration measuring sensor as a signal to a controller;

software executing on the controller for generating a signal indicative of an adjustment of a flow rate of gas into the tank based at least in part on the sulfite concentration measuring sensor transmitted real time sulfite concentration S 1 measurement to maintain a predetermined less than 100% oxidation rate for increased sulfur dioxide removal; and

an inlet operative for supplying ammonia, sodium or magnesium cations to the slurry to achieve a slurry alkalinity for bisulfite formation therein.

2. The system of claim 1 , wherein the signal is further based on a predetermined sulfite concentration of the slurry.

3. The system of claim 2 , wherein the gas comprises oxygen.

4. The system of claim 3 , wherein the slurry is received from a spray tower configured to perform wet flue gas desulfurization.

5. The system of claim 4 , wherein the sulfite concentration measuring sensor comprises a sulfite analyzer.

6. The system of claim 4 , wherein the sulfite concentration measuring sensor comprises a virtual analyzer.

7. The system of claim 1 , wherein the inlet for supply of cations to the slurry is arranged in the tank.

8. A method of controlling the rate of oxidation of sulfites in a slurry comprising the steps of:

receiving a slurry in a tank, the slurry comprising one or more sulfites;

providing a flow of a gas into the tank;

measuring real time a sulfite concentration S 1 of the slurry received in the tank with a sulfite concentration measuring sensor arranged in contact with the slurry received in the tank to obtain a real time sulfite concentration S 1 measurement;

adjusting a flow rate of the gas into the tank based on the real time sulfite concentration S 1 measurement transmitted as a signal from the sulfite concentration measuring sensor to a controller to maintain a predetermined less than 100% oxidation rate; and

supplying ammonia, sodium or magnesium cations to the slurry through an inlet to achieve a slurry alkalinity for bisulfite formation therein.

9. The method of claim 8 , wherein the adjustment of the flow rate of the gas is further based on a predetermined sulfite concentration of the slurry.

10. The method of claim 9 , wherein the sulfite concentration measuring sensor includes a sulfite analyzer used to real time measure the sulfite concentration S 1 .

11. The method of claim 10 , wherein the oxidation of sulfites in the slurry received in the tank is less than 100% for increased sulfur dioxide removal.

12. The method of claim 11 , wherein the cations supplied to the slurry increases the concentration of dissolved sulfites in the slurry for improved flue gas SO 2 removal therewith.

13. The method of claim 12 , wherein the cation comprises magnesium.

14. The method of claim 13 , wherein the gas comprises oxygen.

15. The method of claim 8 , wherein the sulfite concentration measuring sensor comprises a virtual analyzer.