Bypass control system
First Claim
Patent Images
1. A bypass control system for protecting a power recovery expander comprising:
- a power recovery expander;
a first fluid path for supplying combustion gas which is subject to containing large amounts of particulates to said expander as a motive fluid;
first valve means for controlling the flow of gas in said first fluid path;
a second fluid path connected to said first fluid path for bypassing said expander;
second valve means for controlling the flow of gas in said second fluid path;
means for determining the particulate concentration in said combustion gas in said first fluid path and for generating a signal indicative thereof; and
means for fully opening said second valve means in response to said signal when said signal represents a predetermined particulate level so as to prevent said particulates from passing through said expander.
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Accused Products
Abstract
In a fluid catalytic cracking process in the case of a catalyst load dump the catalyst-laden gas is prevented from passing through the power recover expander. This is achieved by establishing a tangential, low pressure bypass flow path in the supply line to the expander which causes the catalyst to be bypassed. An optical sensor senses the catalyst load dump and causes the actuation of the valve necessary to establish the low pressure bypass flow path.
31 Citations
21 Claims
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1. A bypass control system for protecting a power recovery expander comprising:
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a power recovery expander; a first fluid path for supplying combustion gas which is subject to containing large amounts of particulates to said expander as a motive fluid; first valve means for controlling the flow of gas in said first fluid path; a second fluid path connected to said first fluid path for bypassing said expander; second valve means for controlling the flow of gas in said second fluid path; means for determining the particulate concentration in said combustion gas in said first fluid path and for generating a signal indicative thereof; and means for fully opening said second valve means in response to said signal when said signal represents a predetermined particulate level so as to prevent said particulates from passing through said expander. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A bypass control system for protecting a power recovery expander comprising:
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a power recovery expander; a first fluid path means serially including a vertically downward extending portion and a 90°
bend for supplying combustion gas which is subject to containing large amounts of particulates to said expander as a motive fluid;a second fluid path means extending tangentially from approximately the mid point of said 90°
bend and being in fluid communication with said first fluid path;said second fluid path means further serially including a lock hopper means for collecting particulates and a lock hopper discharge line with a normally closed valve means therein; means for determining the particulate concentration in said gas in said first fluid path means and for generating a signal indicative thereof; means for opening said normally closed valve means in response to said signal when said signal represents a predetermined particulate level in said gas in said first fluid path means whereby when said normally closed valve means is closed, said tangentially extending second fluid path means creates a vortex which acts as a separator to remove particulate matter which passes into said lock hopper means and when said normally closed valve means is opened a pressure drop is created in said lock hopper means so that due to the pressure drop, vector velocity and centrifugal force particulates are directed into the second fluid path means to prevent them from passing through said expander. - View Dependent Claims (10)
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11. In a fluid catalytic cracking apparatus including a reactor, means for feeding feedstock to said reactor, a regenerator, and a power recovery expander, a bypass control system for protecting said power recovery expander comprising:
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a first fluid path for supplying combustion gas which is subject to containing large amounts of particulates from said regenerator to said expander as a motive fluid; a second fluid path connected to said first fluid path for bypassing said expander; first valve means for controlling the flow of said gas in said first fluid path; second valve means for controlling the flow of said gas in said second fluid path; means for determining the particulate concentration in said gas in said first fluid path and for generating a signal indicative thereof; means for determining a pressure condition of said regenerator and for generating a signal indicative thereof; means responsive to said signals for fully opening said second valve means in response to a signal representing a predetermined particulate level so as to prevent said particulates from passing through said expander and, if a signal representing a predetermined pressure condition is also received, for closing said means for feeding feedstock to said reactor. - View Dependent Claims (12, 13, 14, 15)
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16. A method for bypass control to protect a power recovery expander comprising the steps of:
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supplying combustion gas which is subject to containing large amounts of particulates to a power recovery expander as the motive fluid; sensing the particulate concentration in the gas supplied to the expander; when the sensed particulate concentration reaches a predetermined level, regulating the flow in a bypass line to prevent the particulates from passing through the expander. - View Dependent Claims (17, 18)
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19. A method for bypass control to protect a power recovery expander comprising the steps of:
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supplying combustion gas which is subject to containing large amounts of particulates to a power recovery expander via a flow path that includes a vertically downward portion and a 90°
bend;sensing the particulate concentration in the gas supplied to the expander; when the sensed particulate concentration reaches a predetermined level, opening a valve in a bypass line that initially extends tangentially from approximately the mid point of the 90°
bend whereby a pressure drop is created in the bypass line and the particulates pass into the bypass line due to the pressure drop and centrifugal force; andwhen the sensed particulate concentration is below a predetermined level keeping the valve in the bypass line closed whereby a vortex is created at the entrance to the bypass line which causes the separation of entrained particulates which slowly descend into the bypass line.
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20. A method for bypass control to protect a power recovery expander in a fluid catalytic cracking process including a reactor, means for feeding feedstock to the reactor, and a regenerator comprising the steps of:
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supplying combustion gas which is subject to containing large amounts of particulates from the regenerator to a power recovery expander; sensing the particulate concentration in the gas supplied to the expander; sensing a pressure condition in the regenerator; when the sensed particulate concentration reaches a predetermined level, regulating the flow in a bypass line to prevent the particulates from passing through the expander and, if the sensed pressure condition is also of a predetermined value, closing the means for feeding feedstock to the reactor to thereby shut down the fluid catalytic cracking process. - View Dependent Claims (21)
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Specification