SYSTEM FOR PREVENTING UNNECESSARY SHUTDOWN OF A HIGH-PURITY GAS PRODUCTION PLANT

• US 20090125127A1
• Filed: 11/03/2008
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Di Santo, Sandro, Warrick, Brian Donald, Bergman, Thomas John JR., Boyer, Rick, Pace, Keith Randall, Schulte, Thomas Robert, Hawke, Michael Henry
• Granted Patent: US 8,280,554 B2
• Time in Patent Office: Days
• US Class Current: 700/80
• CPC Class Codes: B01D 2256/10 Nitrogen
• CPC Class Codes: B01D 2257/104 Oxygen
• CPC Class Codes: B01D 2257/108 Hydrogen
• CPC Class Codes: B01D 2257/502 Carbon monoxide
• CPC Class Codes: B01D 53/0454 Controlling adsorption controlling temperature swing adsorption B01D53/0462, controlling pressure swing adsorption B01D53/047

Abstract

A novel fail-safe temperature monitoring system that can distinguish excessive chemical adsorbent temperature from temperature sensing component failure is provided. This system prevents the gas purifier from shutting down as a result of temperature sensing component failure, and thereby prevents a false shutdown of a high-purity gas production plant.

Claims

1. A system for distinguishing an equipment failure from a potentially catastrophic exothermic reaction in a gas purifier bed, comprising:

providing one or more dual temperature sensors at various locations in the purifier bed, wherein a first set of temperature measuring devices are disposed in close proximity to a corresponding second set of temperature measuring devices forming part of each individual dual temperature sensor;

selecting a first predetermined temperature differential between a first and second temperature measuring device for each individual dual temperature sensor;

triggering an alarm in the event that the first predetermined temperature differential is exceeded prompting the operator to remedy a failure of a single temperature measuring device in an individual dual temperature sensor;

selecting a second predetermined set point temperature, and upon either temperature measuring device in the dual temperature sensor exceeding the second predetermined set point temperature, while the first predetermined temperature differential has not been exceeded, indicates to the operator that a potentially catastrophic exothermic reaction would occur.

2. The system of claim 1, wherein three dual temperature sensors employed are disposed at an upper part, middle part, and lower part of the gas purifier bed.

3. The system of claim 1, wherein the first set of temperature measuring devices are connected to a first receiving computer card, and the second set of temperature measuring devices are connected to a second computer card.

4. The system of claim 1, wherein the gas purifier bed is taken off line upon exceeding the first predetermined temperature differential and the second predetermined temperature set point.

5. The system of claim 1, wherein the first predetermined temperature differential is determined by a temperature difference between two temperature measuring devices of each individual dual temperature sensor.

6. The system of claim 1, wherein the first predetermined temperature differential ranges from about 5°

F. to about 100°

F.

7. The system of claim 1, wherein the second predetermined set point temperature ranges from 120°

F. to about 400°

F.

8. An apparatus designed for preventing failure in a gas purification bed due to an exothermic reaction, comprising:

a gas purification bed having one or more dual temperature sensors at various locations in the gas purification bed,

each dual temperature sensors having two temperature measuring devices in close proximity to one another;

the two temperature measuring devices in each dual temperature sensors being connected to separate temperature receiving computer cards; and

a program logic controller to monitor an exothermic reaction in the gas purification bed based on a first predetermined temperature differential between the temperature measuring devices of each dual temperature sensor and a second predetermined set point temperature, and preventing failure by shutting down the gas purification bed upon the differential between the two temperature measuring devices in a dual temperature sensor being below the first predetermined temperature differential but exceeding the second predetermined set point temperature.

9. The apparatus of claim 8, further comprising three dual temperature sensors disposed at an upper part, middle part, and lower part of the gas purification bed, respectively.

10. The apparatus of claim 8, wherein the temperature sensors are disposed in thermal wells within the purifier bed.

11. The apparatus of claim 8, wherein each temperature measuring device of a dual temperature sensor is placed in a single or separate thermowells.

12. The apparatus of claim 8, wherein the temperature measuring devices are located on the wall of the purifier bed at an upper part, middle part, and lower part of the gas purifier bed.

13. The apparatus of claim 8, further comprising a source of conventional purity nitrogen gas upstream of the gas purification bed having oxygen, carbon monoxide, and hydrogen impurities in an amount ranging from about 0.1 to about 10 ppm.

14. The apparatus of claim 8, further comprising an isolation valve between the source of conventional nitrogen gas and the gas purification bed which is controlled by the program logic controller to isolate the gas purification bed upon exceeding the first predetermined temperature differential and the second predetermined set point temperature.

15. The apparatus of claim 8, wherein upon exceeding the first predetermined temperature of an individual dual temperature sensor, an alarm is triggered and the program logic controller alerts the operator to an equipment failure of said dual temperature sensor.

16. The system of claim 8, wherein the gas purifier bed contains a chemical adsorbent selected from the group consisting of nickel, palladium, zirconium, platinum, rhodium, ruthenium, and titanium.

17. The system of claim 8, further comprising a source of conventional nitrogen gas upstream of the gas purification bed having oxygen, carbon monoxide and hydrogen impurities in an amount ranging from 0.1-10 ppm.

18. The system of claim 8, wherein the gas purifier bed further purifies the conventional purity nitrogen gas stream to an ultra-high-purity level having oxygen, carbon monoxide and hydrogen impurities in an amount ranging 0-20 ppb.