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US 4,289,588 AGranted
Fractional distillation column pumparound heat removal control
AssigneePhillips Petroleum Company
InventorJames A. Hofferber
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Abstract
A control system for a fractional distillation column in which a pumparound stream is used to remove heat from the fractional distillation column is disclosed. A combination of feedforward and feedback control is utilized to control the heat removal by the pumparound stream in such a manner that smoother operation of the fractional distillation column will be accomplished and a closer approach to required product specifications will be approached.
Claims10
A method for controlling the internal reflux flow rate in a fractional distillation column means comprising the steps of:
- supplying a feed to said fractional distillation column means;
- supplying heat to said fractional distillation column means;
- withdrawing a sidedraw stream from an intermediate portion of said fractional distillation column means;
- recycling at least a portion of said sidedraw stream to an intermediate portion of said fractional distillation column means as intermediate external reflux for said fractional distillation column means;
- using at least computing means to establish a first signal representative of a prediction of the flow rate of said intermediate external reflux required to maintain a desired internal reflux flow rate in said fractional distillation column means;
- establishing a second signal representaive of the actual flow rate of said intermediate external reflux;
- using computing means to compare said first signal and said second signal and establishing a third signal responsive to the difference between said first signal and said second signal;
- and
- manipulating the flow rate of said intermediate external reflux in response to said third signal to thereby maintain a desired internal reflux flow rate in said fractional distillation column means.
6 more elements
Dependencies are inferred from the claim text.