Controlled CO preferential oxidation
First Claim
1. In a method of operating a H2 --O2 fuel cell system comprising the principle steps of (1) providing a hydrogen-rich fuel gas having a first carbon monoxide, CO, content sufficient to poison the fuel cell'"'"'s anode, and (2) subjecting said fuel gas to a preferential oxidation reaction for selectively oxidizing said CO with O2 in the presence of said hydrogen to produce a feed stream for said fuel cell which has a second carbon monoxide content less than said first content, the improvement comprising controlling the flow rate of said O2 to said preferential oxidation reaction so as to optimize the consumption of said carbon monoxide from said fuel gas while minimizing the consumption of H2 therefrom by:
- a. measuring the H2 content of said fuel gas;
b. measuring the H2 content of said feed stream;
c. determining a first actual difference, Δ
H2a, between the H2 contents of said feed stream and said fuel gas;
d. determining a second control difference, Δ
H2c, between said first actual difference, Δ
H2a, and a third reference difference, Δ
H2r, which reference difference corresponds to an ideal difference between the H2 contents of said feed stream and said fuel gas;
e. from said second control difference, Δ
H2c, determining the ideal oxygen flow rate, O2i, needed for said preferential oxidation reaction to achieve said reference difference Δ
H2r ;
f. determining a fourth difference, Δ
H2, between the actual oxygen flow rate (O2a) to the preferential oxidation reaction and said ideal oxygen flow rate O2i to such reaction;
g. generating an output signal representative of the fourth difference Δ
O2 ; and
h. modulating the flow rate of the O2 to said preferential oxidation reaction in response to said output signal to achieve said ideal oxygen flow rate O2i.
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Accused Products
Abstract
Method for controlling the supply of air to a PROX reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference therebetween correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference.
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Citations
2 Claims
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1. In a method of operating a H2 --O2 fuel cell system comprising the principle steps of (1) providing a hydrogen-rich fuel gas having a first carbon monoxide, CO, content sufficient to poison the fuel cell'"'"'s anode, and (2) subjecting said fuel gas to a preferential oxidation reaction for selectively oxidizing said CO with O2 in the presence of said hydrogen to produce a feed stream for said fuel cell which has a second carbon monoxide content less than said first content, the improvement comprising controlling the flow rate of said O2 to said preferential oxidation reaction so as to optimize the consumption of said carbon monoxide from said fuel gas while minimizing the consumption of H2 therefrom by:
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a. measuring the H2 content of said fuel gas; b. measuring the H2 content of said feed stream; c. determining a first actual difference, Δ
H2a, between the H2 contents of said feed stream and said fuel gas;d. determining a second control difference, Δ
H2c, between said first actual difference, Δ
H2a, and a third reference difference, Δ
H2r, which reference difference corresponds to an ideal difference between the H2 contents of said feed stream and said fuel gas;e. from said second control difference, Δ
H2c, determining the ideal oxygen flow rate, O2i, needed for said preferential oxidation reaction to achieve said reference difference Δ
H2r ;f. determining a fourth difference, Δ
H2, between the actual oxygen flow rate (O2a) to the preferential oxidation reaction and said ideal oxygen flow rate O2i to such reaction;g. generating an output signal representative of the fourth difference Δ
O2 ; andh. modulating the flow rate of the O2 to said preferential oxidation reaction in response to said output signal to achieve said ideal oxygen flow rate O2i. - View Dependent Claims (2)
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Specification