WET FLUE GAS DESULFURIZATION SYSTEM WITH ZERO WASTE WATER LIQUID DISCHARGE

• US 20170312683A1
• Filed: 04/29/2016
• Published: 11/02/2017
• Est. Priority Date: 04/29/2016
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: General Electric Technology GmbH (GE Aerospace)
• Inventors: DUBE, Sanjay Kumar
• Granted Patent: US 10,350,542 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2251/304 of sodium
• CPC Class Codes: B01D 2251/404 of calcium
• CPC Class Codes: B01D 2257/2045 Hydrochloric acid
• CPC Class Codes: B01D 2257/2047 Hydrofluoric acid
• CPC Class Codes: B01D 2258/0283 Flue gases
• CPC Class Codes: B01D 53/40 Acidic components B01D53/44 takes precedence
• CPC Class Codes: B01D 53/501 by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
• CPC Class Codes: B01D 53/507 by treating the gases with other liquids
• CPC Class Codes: B01D 53/68 Halogens or halogen compounds
• CPC Class Codes: B01D 53/96 Regeneration, reactivation or recycling of reactants
• CPC Class Codes: C02F 1/048 Purification of waste water by evaporation
• CPC Class Codes: C02F 1/06 Flash evaporation

Abstract

A system and a method for industrial plant or utility plant flue gas desulfurization, with zero waste water liquid discharge from a wet flue gas desulfurization system utilized therein, are disclosed herein. The wet flue gas desulfurization system is supplied an absorption liquid for contact with a flue gas to absorb flue gas acid gases. Waste water from the wet flue gas desulfurization system is heated under pressure in a heat exchanger to produce heated waste water, which is supplied to a flash vessel to produce steam. The produced steam is supplied to the flue gas upstream of a particulate collection system and the wet flue gas desulfurization system, supplied to the flue gas upstream of the wet flue gas desulfurization system, or supplied to absorption liquid circulated to the wet flue gas desulfurization system.

Claims

1. A system for evaporating waste water and reducing acid gas emissions, comprising:

a scrubber tower supplied via an inlet an absorbent liquid dispersed therein for acid gas absorption from a flue gas flowing therethrough comprising one or more acid gases;

a heat exchanger operative for pressurized heating of a waste water produced in the scrubber tower to produce heated waste water; and

a flash vessel operative for flash evaporation of the heated waste water to produce steam supplied to flue gas upstream of a particulate collection system and the scrubber tower, supplied to flue gas upstream of the scrubber tower, or supplied to absorbent liquid circulated to the scrubber tower.

2. The system of claim 1, wherein the heat exchanger is operative at a pressure of about 2 bar to about 20 bar, and a temperature of about 100 degrees Celsius to about 200 degrees Celsius.

3. The system of claim 1, wherein the heat exchanger is operative at a pressure of about 3 bar to about 10 bar, and a temperature of about 120 degrees Celsius to about 180 degrees Celsius.

4. The system of claim 1, wherein flue gas supplies heat energy to the heat exchanger.

5. The system of claim 1, wherein flue gas is diverted via ducts to the heat exchanger prior to desulfurization thereof in the scrubber tower.

6. The system of claim 1, wherein a heat transfer agent supplies heat energy to the heat exchanger.

7. The system of claim 1, wherein solid material is added to the waste water prior to pressurized heating of the waste water.

8. The system of claim 1, wherein flue gas having a temperature of about 100 degrees Celsius to about 500 degrees Celsius supplies heat energy to the heat exchanger.

9. A method for evaporating waste water and reducing acid gas emissions, comprising:

using a scrubber tower with a flow of absorbent liquid for desulfurization of a flue gas flowing therethrough;

pressurized heating in a heat exchanger using heat and pressure, waste water collected in the scrubber tower to produce heated waste water;

supplying the heated waste water to a flash vessel to produce steam; and

supplying the produced steam to a flow of flue gas upstream of a particulate collection system and the scrubber tower, to a flow of flue gas upstream of the scrubber tower, or to a circulated flow of absorption liquid dispersed within the scrubber tower.

10. The method of claim 9, wherein the absorbent liquid comprises water and an alkaline reagent.

11. The method of claim 9, wherein the absorbent liquid comprises water and fresh limestone, lime, hydrated lime, sodium carbonate, trona, or alkaline fly ash.

12. The method of claim 9, wherein the heat exchanger is operative for pressurized heating of waste water at a pressure of about 2 bar to about 20 bar, and a temperature of about 100 degrees Celsius to about 200 degrees Celsius.

13. The method of claim 9, wherein the heat exchanger is operative at a pressure of about 3 bar to about 10 bar, and a temperature of about 120 degrees Celsius to about 180 degrees Celsius.

14. The method of claim 9, wherein heat energy from diverted flue gas is used in the heat exchanger for pressurized heating of waste water.

15. The method of claim 9, wherein steam produced in the flash vessel is used as make-up water in the scrubber tower.