Dissolved hydrogen analyzer

• US 6,277,329 B1
• Filed: 03/22/1999
• Issued: 08/21/2001
• Est. Priority Date: 03/22/1999
• Status: Expired due to Fees

• Current Assignee: Camp Dresser & Mckee Incorporated
• Original Assignee: Camp Dresser & Mckee Incorporated
• Inventors: Evans, Patrick J.
• Primary Examiner(s): Warden, Jill
• Assistant Examiner(s): GORDON, BRIAN R
• Application Number:
  US09/273,958
• Time in Patent Office: 883 Days
• Field of Search: 422/80, 422/94, 422/98, 422/88, 73/310.7, 73/191, 73/191.2
• US Class Current: 422/80
• CPC Class Codes: G01N 33/0013 by a chemical reaction a chemical reaction taking place or a gas being eliminated in one or more analysing channels G01N33/0024
• CPC Class Codes: G01N 33/0014 by eliminating a gas by a chemical reaction G01N33/0013; a chemical reaction taking place or a gas being eliminated in one or more analysing channels G01N33/0024
• CPC Class Codes: G01N 33/005 H2
• CPC Class Codes: G01N 33/18 Water
• CPC Class Codes: G01N 33/28 Oils , i.e. hydrocarbon liquids edible oils or edible fats G01N33/03
• CPC Class Codes: G01N 7/14 by allowing the material to emit a gas or vapour, e.g. water vapour, and measuring a pressure or volume difference determining urea G01N33/48742
• CPC Class Codes: Y10T 436/22 Hydrogen, per se
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials

Abstract

The present invention provides apparatuses and processes for the measurement of hydrogen in aqueous solution at concentrations as low as about 0.1 nM. The present invention is capable of accurately and reproducibly measuring the concentration of dissolved hydrogen in an aqueous solution that also contains other dissolved gases, such as oxygen, carbon monoxide and sulfur compounds, such as hydrogen sulfide. In a presently preferred embodiment of a hydrogen analyzer 38 of the present invention, water containing dissolved hydrogen is equilibrated with a carrier gas by means of gas flow through a mass transfer device 10. Carrier gas is equilibrated with hydrogen from the water within a gas equilibration volume 4 and is then circulated, by means of a pump 1, through a circuit 14 that includes a moisture removal component 16, an oxygen removal component 15 and a heated carbon monoxide and sulfur compound removal component 17, which remove water, oxygen, carbon monoxide and sulfur compounds from the carrier gas without consuming or producing hydrogen. A sensor 7 measures the amount of hydrogen in the carrier gas from which moisture, oxygen, carbon monoxide and sulfur compounds have been removed.

Claims

1. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed, wherein the hydrogen sensor is capable of detecting hydrogen in carrier gas equilibrated with hydrogen dissolved in an aqueous medium at a concentration of on the order of 0.1 nM; and

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication.

2. The hydrogen analyzer of claim 1, further comprising a carbon monoxide unit for removal of carbon monoxide from the carrier gas containing hydrogen.

3. The hydrogen analyzer of claim 2, further comprising a sulfur unit for removing sulfur compounds from the carrier gas containing hydrogen.

4. The hydrogen analyzer of claim 1, further comprising a sulfur unit for removing sulfur compounds from the carrier gas containing hydrogen.

5. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed;

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication;

a carbon monoxide unit for removal of carbon monoxide from the carrier gas containing hydrogen; and

a sulfur unit for removing sulfur compounds from the carrier gas containing hydrogen, wherein the sulfur and carbon monoxide removal units comprise a unit including a composition that is capable of removing both carbon monoxide and sulfur compounds from the carrier gas.

6. The hydrogen analyzer of claim 5, wherein the gas equilibrium reservoir is defined by the sulfur and carbon monoxide removal unit.

7. The hydrogen analyzer of claim 5, wherein the carbon monoxide and sulfur compound removal composition is catalyst R3-11.

8. The hydrogen analyzer of claim 7, further comprising a heater coupled to heat the carrier gas containing hydrogen to a temperature of 55°

C. to 80°

C. as the carrier gas flows through the carbon monoxide unit.

9. The hydrogen analyzer of claim 6, further comprising a moisture removal unit for removing moisture from the carrier gas.

10. The hydrogen analyzer of claim 9, wherein the moisture removal unit further comprises a moisture-removal composition selected from the group consisting of molecular sieves and a calcium sulfate preparation.

11. The hydrogen analyzer of claim 6, wherein the carbon monoxide and sulfur compound removal composition is a catalyst preparation comprising magnesium dioxide, copper oxide and aluminum oxide.

12. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed;

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication;

a carbon monoxide unit for removal of carbon monoxide from the carrier gas containing hydrogen; and

a heater coupled to heat the carrier gas containing hydrogen as the carrier gas flows through the carbon monoxide unit.

13. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas, wherein the mass transfer unit is selected from the group consisting of a hollow fiber gas transfer module and a sparger;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed;

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication.

14. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen, wherein the oxygen removal unit comprises an oxygen removal composition;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed; and

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication.

15. The oxygen removal component of claim 14, wherein the oxygen removal unit is an ascorbic acid derivative.

16. The hydrogen analyzer of claim 14, wherein the hydrogen sensor comprises a metal oxide semiconductor.

17. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed, wherein the hydrogen sensor is selected from the group consisting of a Shottky diode and a field effect transistor; and

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication.

18. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

a carbon monoxide unit for removal of carbon monoxide from the carrier gas containing hydrogen;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen;

a sulfur unit for removing sulfur compounds from the carrier gas containing hydrogen;

a moisture unit for removing moisture from the carrier gas;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which carbon monoxide, oxygen, sulfur compounds and moisture have been removed, said hydrogen sensor being capable of detecting hydrogen in carrier gas equilibrated with hydrogen dissolved in an aqueous medium at a concentration of on the order of 0.1 nM; and

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, carbon monoxide, oxygen, sulfur and moisture units and hydrogen sensor, all of which are connected in fluid flow communication.

19. A hydrogen analyzer comprising in gaseous communication:

a mass transfer unit, having a liquid portion and a gaseous portion, through which hydrogen gas is transferred from a liquid analyte to a carrier gas;

a gas equilibrium reservoir within which hydrogen gas transferred from the analyte is equilibrated;

an oxygen unit for removal of oxygen from the carrier gas containing hydrogen that neither produces nor consumes hydrogen;

a hydrogen sensor for measuring the amount of hydrogen in the carrier gas from which oxygen has been removed; and

a pump for moving the carrier gas through the mass transfer unit, gas equilibrium reservoir, oxygen unit and hydrogen sensor, all of which are connected in fluid flow communication.