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US 8,216,429 B2Granted
Detection of distillation column flooding
AssigneeRosemount Inc.
InventorsRoger Kenneth Pihlaja, John Philip Miller
Life of this patent
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Abstract
A method comprises sensing a differential pressure signal, filtering the differential pressure signal, generating a flooding indicator as a function of the filtered differential pressure signal, and indicating the onset of flooding. The differential pressure signal is sensed along a distillation flow path. The filtered differential pressure signal is responsive to a phase inversion along the flow path, and the flooding indicator is responsive to an onset of a flooding condition, based on the phase inversion. The onset of the flooding condition is indicated based on a change in the flooding indicator.
Claims28
A system comprising:
- a pressure sensor for sensing differential pressure across a vertical height of a distillation column;
- a filter for filtering the differential pressure as a function of frequency to produce a filtered differential signal emphasizing high-frequency components in the differential pressure and suppressing low-frequency components in the differential pressure;
- a processor for generating an indicator function based on the filtered differential pressure signal, wherein the indicator function comprises a standard deviation of the filter output and is indicative of a flooding condition in the distillation column;
- an indicator for indicating onset of the flooding condition in the distillation column based on a change in the indicator function;
- and
- a controller for controlling the distillation column based on the change in the indicator function, wherein the controller is configured to control a mass transfer rate between liquid and vapor phases within the distillation column to encourage condensation and separation without runaway flooding.
3 more elements
An apparatus comprising:
- a sensor configured to sample differential pressure;
- means for connecting the sensor across a vertical height of a two-phase liquid and vapor phase counter-current flow distillation column;
- means for generating a frequency-filtered signal emphasizing high-frequency components in the differential pressure and suppressing low-frequency components in the differential pressure, such that the frequency-filtered signal is responsive to foaming within the vertical height of the distillation column;
- means for generating an indicator function comprising a standard deviation of the frequency-filtered signal, such that the indicator function is indicative of a phase inversion in the two-phase liquid and vapor phase counter-current flow;
- means for indicating a flooding condition in the distillation column based on a change in the indicator function;
- and
- means for controlling a mass transfer rate between the liquid and vapor phases within the distillation column based on a change in the indicator function, in order to encourage condensation and separation without runaway flooding.
4 more elements
A transmitter comprising:
- a differential pressure sensor;
- a housing for the differential pressure sensor, the housing having differential pressure ports configured to connect the differential pressure sensor to a distillation column;
- a filter connected to the pressure sensor, the filter configured to generate a filter output emphasizing high-frequency components in the differential pressure and suppressing low-frequency components in the differential pressure;
- a processor connected to the filter, the processor configured to generate an indicator function comprising a standard deviation of the filter output, wherein the indicator function is indicative of a flooding condition in the column;
- and
- an interface connected to the processor, the interface configured to indicate onset of the flooding condition based on a change in the indicator function;
- and
- a controller for controlling the distillation column based on the change in the indicator function, wherein the controller is configured to control a mass transfer rate between liquid and vapor phases within the distillation column to encourage condensation and separation without runaway flooding.
5 more elements
Dependencies are inferred from the claim text.