Flue Gas Monitoring And Dynamic Spiking For Sulfur Trioxide/Sulfuric Acid

• US 20110097809A1
• Filed: 10/27/2009
• Published: 04/28/2011
• Est. Priority Date: 10/27/2009
• Status: Active Grant

• Current Assignee: Clean Air Engineering, Inc.
• Original Assignee: Clean Air Engineering, Inc.
• Inventors: Evans, Scott A., Roesler, Daniel H.
• Granted Patent: US 8,021,617 B2
• Time in Patent Office: Days
• US Class Current: 436/102
• CPC Class Codes: G01N 2021/3595 using FTIR
• CPC Class Codes: G01N 33/0042 for SO2, SO3
• CPC Class Codes: Y10T 436/156666 Sulfur containing
• CPC Class Codes: Y10T 436/18 Sulfur containing
• CPC Class Codes: Y10T 436/186 Sulfur dioxide

Abstract

Systems and methods are disclosed for measuring sulfur trioxide/sulfuric acid content of flue gas. A probe is provided that extracts two separate lines of gas samples simultaneously from the flue gas. One of the two lines is dynamically spiked with a known quantity of sulfur trioxide, preferably generated in the probe. A comparison of sulfur trioxide/sulfuric acid content measurements from the spiked and unspiked lines helps identify and adjust for inherent biases in the measuring system. Also disclosed are catalyst structures and methods for use thereof for generating sulfur trioxide at known concentration.

Claims

1. A system for monitoring sulfur trioxide/sulfuric acid levels in an emission stream flowing through an exhaust, the system comprising:

a probe positionable relative to the exhaust to be able to extract essentially simultaneously a first supply train of sample gas from the exhaust and a second supply train of sample gas from the exhaust;

means for measuring sulfur trioxide/sulfuric acid content in the first supply train;

means for supplying SO₂ gas of a known quantity to a catalyst, converting that SO₂ gas that has been supplied to the catalyst to SO₃ gas, spiking the second supply train with the catalyst converted SO₃ gas to create a spiked train, and then measuring sulfur trioxide/sulfuric acid content in the spiked train;

whereby the system is configured such that a comparison of the measuring can help validate the system.

2. The system of claim 1, wherein the probe houses a catalyst capable of converting SO₂ gas to SO₃ gas.

3. The system of claim 2, wherein heating coils are positioned adjacent to the catalyst.

4. The system of claim 3, wherein the heating coils can heat the catalyst to a temperature above 750°

F.

5. The system of claim 3, wherein the heating coils are configured and operated to heat the catalyst to a temperature of between 750°

F. and 850°

F.

6. The system of claim 1, wherein the probe comprises an inlet line for feeding SO₂ gas to the catalyst, a carrier line for carrying SO₃ gas from the catalyst to a connection to the second supply train, and an outlet line for carrying SO₃ spiked vapor to a connector to measuring equipment, as well as a line for carrying an unspiked sample of flue gas.

7. The system of claim 6, wherein

thermocouples are provided in the probe.

8. A method of monitoring sulfur trioxide/sulfuric acid levels in an emission stream flowing through an exhaust, the method comprising:

placing a probe relative to the exhaust so as to extract essentially simultaneously a first supply train of sample gas from the exhaust and a second supply train of sample gas from the exhaust;

measuring the sulfur trioxide/sulfuric acid content in the first supply train;

spiking the second supply train with a known quantity of SO₃ gas;

measuring the sulfur trioxide/sulfuric acid content in the second supply train after the spiking; and

then comparing results of the measuring.