STEAM/CARBON RATIO DETECTION AND CONTROL
Steam is provided to the primary inlet ( 16 ) of an ejector ( 13 ), which also receives natural gas at a secondary inlet ( 28 ). A computer responds to a signal ( 37 ) indicating current in the load of a fuel cell as well as a signal ( 43 ) indicating temperature of a steam reformer ( 10 ) to move a linear actuator ( 23 ) to control a needle ( 21 ) that adjusts the size of the steam orifice. Reformate is fed to a separator scrubber ( 48 ) which cools the reformate to its dew point indicated by a sensor ( 71 ). From that, a controller ( 25 ) generates the fuel/carbon ratio for display ( 84 ) and to bias a signal on a line ( 24 ) regulating the amount of steam passing through an ejector ( 13 ) to the inlet ( 11 ) of the reformer. Alternatively, the reformate may be cooled to its dew point by a controllable heat exchanger ( 58 a ) in response to pressure ( 94 ) and temperature ( 71 ) signals.
1 . A method comprising:
providing a flow of steam to a primary inlet ( 16 ) of an ejector ( 13 );
providing a flow of hydrocarbon fuel to a secondary inlet ( 28 ) of said ejector;
providing effluent of said ejector to a steam reformer ( 11 );
cooling reformate from the steam reformer to its dew point in apparatus ( 46 , 58 ; 58 a );
characterized by:
generating in a controller ( 25 ), a ratio signal indicative of the steam/carbon ratio of the cooled reformate as a function of the dew point of cooled reformate indicated by a sensor ( 71 ).
2 . A method according to claim 1 further characterized by:
presenting in a display ( 84 ) said steam/carbon ratio indicated by said ratio signal.
3 . A method according to claim 1 further comprising:
said controller ( 25 ) providing on a first line ( 24 ) a signal indicative of the amount of steam to be provided to said steam reformer ( 11 ) and providing on a second line ( 33 ), as a function of the signal on said first line, a signal indicative of the amount of fuel to be provided to said steam reformer;
further characterized in that:
said controller modifies the signals on said first and/or second lines as a function of said ratio signal.
4 . A method according to claim 1 further characterized in that:
said step of providing hydrocarbon fuel comprises providing natural gas.
5 . A method according to claim 1 further characterized in that:
said step of cooling comprises cooling the reformate in a separator scrubber ( 46 ) of an ammonia removal subsystem ( 49 ).
6 . A method according to claim 1 further characterized in that:
said step of cooling comprises cooling the reformate in a controllable heat exchanger ( 58 a ).
7 . A method comprising:
providing a mixture of steam and hydrocarbon fuel to a steam reformer ( 10 );
cooling reformate flowing from said reformer to provide a reformate flow ( 69 ) cooled to its dew point;
characterized by:
providing a temperature signal ( 72 ) indicative of the dew point of the cooled reformate flow; and
adjusting the steam/carbon ratio of the mixture in response to the temperature signal.
8 . Apparatus comprising:
a steam reformer ( 10 );
means ( 13 , 23 , 30 ) for providing a mixture of steam and hydrocarbon fuel to the steam reformer;
means ( 49 , 58 a ) for cooling reformate flowing from said reformer to provide a reformate flow ( 69 ) cooled to its dew point;
characterized by:
means ( 71 ) for providing a temperature signal indicative of the dew point of the cooled reformate flow; and
means ( 25 , 13 , 23 , 30 ) for adjusting the steam/carbon ratio of the mixture in response to the temperature signal.
9 . Apparatus comprising:
means ( 15 ) for providing a flow of steam to a primary inlet ( 16 ) of an ejector ( 13 );
means ( 35 ) for providing a flow of hydrocarbon fuel to a secondary inlet ( 28 ) of said injector;
means ( 12 ) for providing effluent said ejector to a steam reformer ( 10 );
apparatus ( 49 , 58 a ) for cooling reformate from the steam reformer to its dew point;
characterized by:
a controller ( 25 ) configured to generate a ratio signal indicative of the steam/carbon ratio of the cooled reformate as a function of the dew point of cooled reformate indicated by a sensor ( 71 ).
10 . Apparatus comprising:
a controller ( 25 );
an ejector ( 13 ) configured to receive a flow of steam at a primary inlet ( 16 ) and a flow of hydrocarbon fuel at a secondary inlet ( 28 );
a steam reformer ( 10 ) configured to receive outflow of said ejector at an inlet ( 11 );
apparatus ( 48 a, 58 a ) configured to cool reformate from the reformer to its dew point;
a temperature sensor ( 71 ) providing to said controller a temperature signal ( 72 ) indicative of the dew point temperature of reformate;
characterized by:
said controller configured to generate in response to said temperature signal, a ratio signal indicative of the steam/carbon ratio of the reformate.
11 . Apparatus according to claim 10 further characterized by:
a display ( 84 ) configured to display the steam/carbon ratio indicated by said ratio signal.
12 . Apparatus according to claim 10 wherein:
said controller ( 25 ) is configured to provide on a first line ( 24 ) a signal indicative of the amount of steam to be provided to said steam reformer ( 10 ) and to provide on a second line ( 33 ), as a function of the signal on said first line, a signal indicative of the amount of fuel to be provided to said steam reformer; and
further characterized in that:
said controller is configured to modify the signal on said first and/or second lines as a function of said ratio signal.
13 . Apparatus according to claim 10 further characterized in that:
said ejector ( 13 ) is configured to receive natural gas at the secondary inlet ( 28 ).
14 . Apparatus according to claim 10 further characterized in that:
said apparatus is a separator scrubber ( 48 ) of an ammonia removal subsystem ( 49 ).
15 . Apparatus according to claim 10 further characterized in that:
said apparatus is a controllable heat exchanger ( 58 a ).