System for hydrogen detection in cooling towers

1. A method comprising:

drawing a slip stream sample from a cooling fluid stream, the cooling fluid stream being fluidically coupled to an outlet of a heat exchanger and an inlet of a cooling tower;

conveying the slip stream sample into an expansion chamber of a detection unit;

controlling a liquid level in the expansion chamber with a control valve and a liquid level sensor, the liquid level sensor disposed within the expansion chamber;

analyzing the slip stream sample and measuring a concentration of hydrogen gas within a headspace of the expansion chamber; and

returning the slip stream sample to the cooling fluid stream.

2. The method of claim 1 wherein the cooling fluid stream comprises water and at least one gas selected from the group consisting of hydrogen, methane, ethane, ethylene, acetylene, propane, propylene, n-butane, iso-butane, and combinations thereof.

3. The method of claim 2 wherein the cooling fluid is contaminated with the at least one gas while in the heat exchanger.

4. The method of claim 2 wherein the at least one gas is separated from the water into the headspace.

5. The method of claim 1 wherein the measuring a concentration of hydrogen gas comprises measuring parts per million of hydrogen in the headspace or a percentage lower explosive limit of hydrogen in the headspace.

6. The method of claim 1 further comprising:

comparing a signal, from the detection unit, to a set point for a concentration of hydrogen; and

activating an alarm when the concentration of hydrogen in the headspace exceeds the set point.

7. The method of claim 1 further comprising measuring a concentration of at least one gas selected from the group consisting of methane, ethane, ethylene, acetylene, propane, propylene, n-butane, or iso-butane, and combinations thereof.

8. An apparatus comprising:

a flow line fluidically coupled to an outlet of a heat exchanger, wherein the flow line is a slip stream from a cooling fluid stream;

an expansion chamber fluidically coupled to the flow line, wherein the expansion chamber comprises a return line fluidically coupled to the cooling fluid stream, a liquid level sensor disposed within the expansion chamber;

a control valve operable to maintain a liquid level in the expansion chamber;

a hydrogen detector disposed within the expansion chamber, the hydrogen detector being operable to quantify a concentration of hydrogen in the slip stream before the slip stream is returned to the cooling fluid stream; and

an alarm.

9. The apparatus of claim 8 further comprising a strainer fluidically coupled between the heat exchanger and the expansion chamber.

10. The apparatus of claim 9 , wherein the control valve is disposed upstream from the expansion chamber.

11. The apparatus of claim 8 wherein the gas detector is further operable to quantify at least one gas selected from the group consisting of methane, ethane, ethylene, acetylene, propane, propylene, n-butane, or iso-butane, and combinations thereof.

12. The apparatus of claim 8 , further comprising a relief valve that is disposed on the expansion chamber.

13. The apparatus of claim 9 further comprising a flow meter fluidically coupled between the heat exchanger and the expansion chamber.

14. A system comprising:

a heat exchanger;

a cooling tower;

a cooling stream fluidically coupled to an outlet of the heat exchanger and an inlet of the cooling tower;

an expansion chamber having an inlet to receive a slip stream from a cooling fluid stream;

a liquid level sensor disposed within the expansion chamber;

a control valve operable to maintain a liquid level in the expansion chamber; and

a hydrogen detector disposed in a headspace within the expansion chamber, wherein the hydrogen detector is operable to quantify a concentration of hydrogen in the slip stream before the slip stream is returned to the cooling fluid stream.

15. The system of claim 14 , further comprising a relief valve that is disposed on the expansion chamber.

16. The system of claim 15 , wherein conditions in the expansion chamber include ambient conditions.

17. The system of claim 16 wherein the signal is a 4-20 mA signal.

18. The system of claim 14 wherein the hydrogen detector is configured to detect a concentration of hydrogen in parts per million, as a percentage of lower explosive limit, or a combination thereof.

19. The system of claim 14 further comprising a gas detector configured to detect at least one gas selected from the group consisting of methane, ethane, ethylene, acetylene, propane, propylene, n-butane, or iso-butane, and combinations thereof.

20. The system of claim 14 further comprising a flow meter fluidically coupled between the heat exchanger and the expansion chamber.