Structure and method for indicating undesirable constituents in a fuel cell system

Patent metadata

Field	Value
Publication number	US-9859580-B2
Application number	US-201514589403-A
Country	US
Kind code	B2
Filing date	Jan 5, 2015
Priority date	Jan 6, 2014
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

An optical detection system for detecting undesirable constituents in a fuel cell system includes a sensing material configured to change color in the presence of the undesirable constituents and at least one sensor configured to register the change in color of the sensing material. The sensor is coupled to a corresponding light source. The sensing material, the sensor and the light source are enclosed in a housing.

First claim

The invention claimed is:

1. A method of detecting undesirable constituents in a fuel cell system, comprising:
providing an optical detection system comprising:
a processor;
a sensing material configured to change color in the presence of the undesirable constituents;
constituent sensors disposed at different locations along a fuel inlet line of the fuel cell system and configured to register the change in color of the sensing material;
a reference material configured to not change color in the presence of the undesirable constituents; and
a reference sensor configured to register the change in color of the reference material;

using the processor to detect an undesirable constituent in a fuel stream of the fuel cell system, by applying a different alarm detection algorithm to an output of each of the constituent sensors, the alarm detection algorithms being based on a difference between a change of color of the sensing material and the reference material; and
generating an alarm signal when an alarm criterion of at least one of the alarm detection algorithms is met,
wherein the alarm detection algorithms are selected from a least-squares threshold comparison algorithm, a first derivative threshold comparison algorithm, a second derivative threshold comparison algorithm, a sigmoid-based function threshold comparison algorithm, and an absolute value threshold comparison algorithm.

2. The method of claim 1 , wherein the undesirable constituent comprises sulfur.

3. The method of claim 1 , wherein the sensing material and the reference material each comprise paint or dye on a substrate, wherein each of the constituent sensors comprises a photodetector facing the substrate, and wherein illuminating the sensing material comprises illuminating the substrate.

4. The method of claim 2 , wherein the constituent sensors include at least one red color sensor, at least one green color sensor, and at least one blue color sensor.

5. The method of claim 2 , wherein at least one of the constituent sensors and a portion of the sensing material are positioned in a fuel inlet line or in a slipstream line of the fuel cell system.

6. The method of claim 2 , wherein the alarm criterion of one of the detection algorithms is met when coefficients of a least squares regression of sensor values with respect to time fall outside a preset range.

7. The method of claim 2 , wherein the alarm criterion of one of the detection algorithms is met when a first derivative, a second derivative, or a sum of absolute values of sensor values with respect to time falls outside a preset range.

8. The method of claim 2 , wherein the generating the alarm signal comprises generating the alarm signal when the alarm criterion of at least two of the alarm detection algorithms is met.

9. The method of claim 2 , wherein one of the detection algorithms comprises differentiating, by the processor, between a positive and negative slope of signal variation for at least one of the constituent sensors.

10. The method of claim 2 , wherein:
one of constituent sensors and the portion of the sensing material are disposed along the fuel inlet line upstream of a primary sorbent bed of the fuel cell system; and
one of constituent sensors and a portion of the sensing material are located in the fuel inlet line downstream of the primary sorbent bed.

11. The method of claim 1 , wherein the constituent sensors and the reference sensor are each coupled to a light source, and wherein the sensing material, the constituent sensors, the reference material, the reference sensor and the light sources are enclosed in a housing.

12. The method of claim 1 , further comprising subtracting a value of a signal from the reference sensor from a value of a signal from the at least one of the constituent sensors to increase a signal-to-noise ratio for a signal corresponding to the change in color of the sensing material.

13. A method of controlling fuel flow to a sorbent bed in a fuel cell system, comprising:
directing fuel through a primary sorbent bed to a fuel cell stack;
diverting a portion of fuel entering the primary sorbent bed into a sensor configured to detect undesirable constituents exiting the primary sorbent bed;
calculating a flow ratio based on a ratio of a total amount of fuel flowing through the primary sorbent bed to a total amount of fuel flowing through the sensor;
determining an acceptable sensor value based on the calculated flow ratio;
detecting a breakthrough event in the primary sorbent bed when a sensor value output from the sensor exceeds the acceptable sensor value; and
directing fuel away from the primary sorbent bed in response to detecting the breakthrough event.

14. The method of claim 13 , further comprising:
directing at least a portion of the fuel flow through a reserve sorbent bed; and
periodically bypassing the reserve sorbent bed, the reserve sorbent bed being external to a fuel processing module and larger than the primary sorbent bed.

15. The method of claim 13 , wherein the sensor comprises at least one of a color change detector, a resistance change detector, and an artificial nose.

16. A method of controlling fuel flow to a sorbent bed in a fuel cell system, comprising:
flowing fuel through a primary sorbent bed to a fuel cell stack;
detecting a breakthrough event in the primary sorbent bed, by using a fuel cell stack performance monitoring system to detect an at least 5% decrease in a voltage of the fuel cell stack; and
directing fuel away from the primary sorbent bed when the breakthrough event is detected.

Assignees

• Bloom Energy Corp

Inventors

• Ballantine Arne
• Trevisan David
• Ramani Venkat
• Campbell Emma
• Mahler Jessica
• Wright Michael
• Schrieber Jeffrey W

Classifications

• H01M8/04388

  of anode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/0662

  Treatment of gaseous reactants or gaseous residues, e.g. cleaning · CPC title

• H01M8/04447

  of anode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/04776

  at auxiliary devices, e.g. reformer, compressor, burner · CPC title

• H01M8/0444

  Concentration; Density (H01M8/04492 takes precedence) · CPC title