Apparatus and method for reducing instances of pump de-priming

• US 20050183948A1
• Filed: 09/21/2004
• Published: 08/25/2005
• Est. Priority Date: 09/22/2003
• Status: Abandoned Application

• Current Assignee: Hydrogenics Corporation (Cummins Incorporated)
• Original Assignee: Hydrogenics Corporation (Cummins Incorporated)
• Inventors: Vale, Michael, Rusta-Sallehy, Ali
• Application Number:
  US10/944,868
• Publication Number:
  US 20050183948A1
• Time in Patent Office: Days
• US Class Current: 204/228.600
• CPC Class Codes: C25B 15/02 Process control or regulation
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04701 Temperature
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Abruptly shutting down an electrolyzer cell module during normal operation may, in some instances, be necessary when one or more process and operating parameters uncontrollably deviate into an unsafe range. However, abruptly shutting down an electrolyzer cell module may have residual effects that make it difficult to restart the electrolyzer cell module. In particular, in some instances a circulation pump is de-primed by the accumulation of gas bubbles within the circulation pump, which normally do not exist during normal operation since a fluid containing dissolved gas molecules is pressurized to ensure that the gas remains dissolved. In some embodiments of the invention there is provided a modified safety system that can controllably shutdown an electrolyzer cell module in an emergency situation so as to prevent instances of pump de-priming.

Claims

1. An electrolyzer cell module comprising:

an electrolyzer cell stack for electrolysing a compound liquid to produce at least one gas;

a plurality of balance-of-plant elements connected to the electrolyzer cell stack, for regulating the operation of the electrolyzer cell stack;

a safety system connected to at least some of the balance-of-plant elements and the electrolyzer cell stack, for monitoring at least one process and operating parameter related to the operation of the electrolyzer cell module and evaluating whether or not at least one alarm threshold has been violated by the at least one process and operating parameter;

a computer usable medium, in communication with the safety system, having computer program readable code means embodied therein for emergency stoppage of the normal operation of the electrolyzer cell module when the at least one alarm threshold has been violated, the computer program readable code means including;

instructions for stopping the electrolysis of the compound liquid within the electrolyzer cell stack, thereby stopping the production of the at least one gas;

instructions for operating the electrolyzer cell module so as to flush out residual amounts of the at least one gas dissolved in the compound liquid over a time period; and

instructions for cutting-off power, at the end of the time period, to all of the elements included in the electrolyzer cell module required for flushing out residual amounts of the at least one gas dissolved in the compound liquid, to shut-down the electrolyzer cell stack.

2. An electrolyzer cell module according to claim 1, wherein the computer program readable code means further comprises:

instructions for cutting-off power to some of the balance-of-plant elements included in the electrolyzer cell module, while continuing to provide power to other balance-of-plant elements required to flush out the residual amounts of the at least on gas dissolved in the compound liquid within the electrolyzer cell module.

3. An electrolyzer cell module according to claim 2, wherein the balance-of-plant elements that continue to receive power during an emergency stoppage include a circulation pump and pressure regulating devices.

4. An electrolyzer cell module according to claim 1 further comprising a pressure release means that is operable to slowly and controllably release the pressure within the electrolyzer cell module as it is being turned off.

5. An electrolyzer cell module according to claim 4, wherein the pressure release means in comprised of a combination of valves.

6. An electrolyzer cell module according to claim 5, wherein the combination of valves is comprised of a need/orifice valve and a second valve connected in series, wherein the second valve is opened when the electrolyzer cell module is shut down.

7. An electrolyzerr cell module according to claim 6, wherein the second valve is one of a normally open valve and a normally closed valve.

8. An electrolyzer cell module according to claim 4 further comprising a hydrogen collection device and an oxygen collection device.

9. An electrolyzer cell module according to claim 8, wherein the pressure release means is connected to one of the hydrogen collection device and the oxygen collection device.

10. An emergency stoppage method of operating an electrolyzer cell module that includes a number of balance-of-plant elements and an electrolyzer cell stack, the method comprising:

stopping electrolysis of a compound liquid, thereby stopping the production of at least one gas dissolved in the compound liquid;

flushing out residual amounts of the at least one gas evolved from the compound liquid by operating some of the balance-of-plant elements included in the electrolyzer cell module and not others; and

cutting-off power, to all of the elements included in the electrolyzer cell module required to flush out the residual amounts of the at least one gas dissolved in the compound liquid, to shut-down the operation of the electrolyzer cell stack.

11. A method according to claim 10 further comprising:

controllably releasing the pressure within the electrolyzer cell module as the residual amounts of the at least one gas are flushed from the electrolyzer cell module.

12. A method according to claim 11 further comprising:

cutting-off power to some of the balance-of-plant elements included in the electrolyzer cell module, while continuing to provide power to other balance-of-plant elements required to flush out the residual amounts of the at least on gas dissolved in the compound liquid within the electrolyzer cell module.