GENERATION OF SULFUR TRIOXIDE AND SULFURIC ACID

• US 20100284899A1
• Filed: 05/11/2009
• Published: 11/11/2010
• Est. Priority Date: 05/11/2009
• Status: Active Grant

• Current Assignee: Thermo Fisher Scientific Incorporated
• Original Assignee: Thermo Fisher Scientific Incorporated
• Inventors: Li, Yongquan, Marcotte, Bryan A., Kita, Dieter, Socha, Jeffrey
• Granted Patent: US 8,052,949 B2
• Time in Patent Office: Days
• US Class Current: 423/522
• CPC Class Codes: C01B 17/76 by contact processes
• CPC Class Codes: C01B 17/80 Apparatus
• CPC Class Codes: G01N 2001/2893 Preparing calibration standards
• CPC Class Codes: G01N 33/0006 Calibrating gas analysers
• CPC Class Codes: G01N 33/0042 SO2 or SO3
• CPC Class Codes: Y10T 436/10 Composition for standardization, calibration, simulation, stabilization, preparation or preservation; processes of use in preparation for chemical testing

Abstract

Configurations herein include a novel process and apparatus for generating and maintaining sulfur trioxide gas. The generation system and process operate to provide sulfur trioxide calibration gas for calibrating sulfur trioxide detection devices. The system and process provides a known, concentration of sulfur trioxide gas via a heated catalyst, which enables accurate calibration of measurement equipment. The system functions in part by controlling temperature, amount of moisture, residence time, catalyst selection, diluting generated sulfur trioxide and by locating the sulfur trioxide generator at a point of injection of a sulfur trioxide detection system.

Claims

1. A method of generating and maintaining sulfur trioxide gas, the method comprising:

receiving a known concentration of sulfur dioxide gas;

receiving an oxidizing agent gas;

exposing the known concentration of sulfur dioxide gas and the oxidizing agent gas to a catalyst, the catalyst being heated, to react the known concentration of sulfur dioxide gas and the oxidizing agent gas into a known concentration of sulfur trioxide gas; and

maintaining the known concentration of sulfur trioxide gas in a gaseous state.

2. The method of claim 1, wherein maintaining the known concentration of sulfur trioxide gas in the gaseous state includes:

diluting the sulfur trioxide gas with a dilution gas; and

maintaining the diluted sulfur trioxide gas above a conversion point temperature of sulfuric acid.

3. The method of claim 2, further comprising:

passing a portion of the diluted sulfur trioxide gas, having a known concentration of sulfur trioxide gas, through a sulfur trioxide detection device.

4. The method of claim 3, wherein passing the portion of the diluted sulfur trioxide gas, having a known concentration of sulfur trioxide gas, through the sulfur trioxide detection device includes:

passing the diluted sulfur trioxide gas through a multi-pass optical cell that measures a concentration of sulfur trioxide.

5. The method of claim 3, further comprising:

calibrating the sulfur trioxide detection device by measuring the known concentration of sulfur trioxide gas passing through the sulfur trioxide detection device; and

adjusting the measurements of the sulfur trioxide detection device based on calibration using the known concentration of sulfur trioxide gas.

6. The method of claim 1, wherein receiving the known concentration of sulfur dioxide gas includes pre-heating the sulfur dioxide gas before exposing the sulfur dioxide gas to the catalyst.

7. The method of claim 1, further comprising:

heating the catalyst to above about 550 degrees Celsius to restore a degraded condition of the catalyst, the degraded condition causing reduced efficiency of converting the sulfur dioxide into the sulfur trioxide.

8. The method of claim 1, wherein exposing the known concentration of sulfur dioxide gas and the oxidizing agent gas to a catalyst includes heating the catalyst to a temperature between 225 degrees Celsius and 600 degrees Celsius.

9. The method of claim 1, wherein exposing the known concentration of sulfur dioxide gas and the oxidizing agent gas to a catalyst includes:

exposing the known concentration of sulfur dioxide gas and the oxidizing agent gas to a catalyst at different flow rates at different time periods; and

adjusting the temperature of the catalyst according to the different flow rates at the different time periods to yield a conversion of sulfur dioxide gas to sulfur trioxide gas at an efficiency level above about 99%.

10. The method of claim 1, further comprising:

converting the sulfur trioxide gas to sulfuric acid by adding dihydrogen monoxide; and

heating the sulfuric acid to a temperature sufficient to convert the sulfuric acid to sulfur trioxide gas.

11. The method of claim 1, wherein the method of generating and maintaining sulfur trioxide gas occur less than about 6 feet from a sulfur trioxide detection device.

21. The method as in claim 1 further comprising:

preventing exposure of the sulfur dioxide gas to water.

12. A system comprising:

an input to receive a known concentration of sulfur dioxide gas and an oxidizing agent gas, the input connected to a chamber;

a heater;

the chamber including a catalyst, the chamber constructed to expose the known concentration of sulfur dioxide gas and the oxidizing agent gas to the catalyst, the catalyst having a surface area, the heater configured to heat the catalyst to react the known concentration of sulfur dioxide gas and the oxidizing agent gas into a known concentration of sulfur trioxide gas;

an output, connected to the chamber, to emit the known concentration of sulfur trioxide gas; and

a sulfur trioxide gas delivery conduit connected to the output, to maintain sulfur trioxide gas in a gaseous state.

13. The system of claim 12, further comprising:

a sulfur trioxide detection device, connected to the sulfur trioxide gas delivery conduit, for receiving the known concentration of sulfur trioxide gas, wherein the system includes a heat source to maintain the known concentration of sulfur trioxide gas above a conversion point temperature of sulfuric acid.

14. The system of claim 13, further comprising:

an inertial probe designed for connection to a flue gas system, the inertial probe enclosing the input, the chamber, the output, the sulfur trioxide gas delivery conduit, and the sulfur trioxide detection device.

15. The system of claim 14, wherein the inertial probe maintains an internal temperature substantially above a conversion point below which sulfur trioxide converts to sulfuric acid.

16. The system of claim 13, wherein the sulfur trioxide detection device includes a multi-pass optical cavity.

17. The system of claim 12, wherein a surface area of the catalyst is sufficiently large for the known concentration of sulfur dioxide gas to react and produce a known concentration of sulfur trioxide gas at an efficiency above about 99 percent.

18. The system of claim 12, further comprising:

a pair of porous frits that position loose catalyst material to fill a cross section within the chamber.

19. The system of claim 12, further comprising a hydrator for converting at least a portion of the sulfur trioxide gas to sulfuric acid.

20. The system of claim 12, wherein the catalyst is selected from the group consisting of:

platinum, palladium, vanadium, nickel, and iron oxide.