Temperature control for preheating a crude oil feedstock
AssigneePhillips Petroleum Company
InventorDanny L. Furr
Life of this patent
Estimating the term…
Abstract
In a process in which a feedstock is provided through a desalting unit prior to introduction into a fractional distillation column, the feed stream flowing to the desalting unit is split and passed through multiple heat exchangers. Method and apparatus is provided for maintaining a desired effluent flow rate out of the desalting unit and for maintaining the temperatures of the split feed streams substantially equal. After passing through the desalting unit the feed stream may again be split and passed through multiple heat exchangers prior to introduction of the feed stream into the fractional distillation column. Method and apparatus is also provided for maintaining the temperature of the split feed streams provided from the desalting unit substantially equal.
Claims10
Apparatus comprising:
- means for splitting a crude oil feed stream into at least first and second feed streams;
- a desalting means;
- a first heat exchange means;
- means for providing said first feed stream through said first heat exchange means to said desalting means;
- a second heat exchange means;
- means for providing said second feed stream through said second heat exchange means to said desalting means;
- means for withdrawing crude oil from said desalting means;
- means for establishing a first signal representative of the flow rate of the crude oil flowing from said desalting means;
- means for establishing a second signal representative of the desired flow rate of the crude oil flowing from said desalting means;
- means for establishing a biasing term which is responsive to the delay between the time said second signal is changed and the time said first signal changes in response to a change in said second signal;
- means for multiplying said first signal by said biasing term to thereby establish a third signal which is representative of what the actual flow rate of the crude oil flowing from said desalting means would be if there were no delay between the time said second signal is changed and the time said first signal changes in response to a change in said second signal;
- means for comparing said third signal and said second signal and for establishing a fourth signal responsive to the difference between said second signal and said third signal;
- means for establishing a fifth signal which is representative of the percentage of said crude oil feed stream which must be provided as said first feed stream to said desalting means to maintain the temperature of said first feed stream after said first feed stream passes through said first heat exchange means substantially equal to the temperature of said second feed stream after said second feed stream passes through said second heat exchange means;
- means for multiplying said fourth signal by said fifth signal to establish a sixth signal representative of the required flow rate of said first feed stream;
- and
- means for manipulating the flow rate of said first feed stream in response to said sixth signal.
In a process in which a crude oil feed stream flowing to a desalting process is split into at least first and second feed streams for the purpose of preheating said crude oil feed stream prior to introducing said crude oil feed stream into said desalting process, a method for controlling the flow rate of crude oil flowing from said desalting process and for maintaining the temperature of said first feed stream after preheating substantially equal to the temperature of said second feed stream after preheating, said method comprising the steps of:
- establishing a first signal representative of the flow rate of the crude oil flowing from said desalting process;
- establishing a second signal representative of the desired flow rate of the crude oil flowing from said desalting process;
- establishing a biasing term which is responsive to the delay between the time said second signal is changed and the time said first signal changes in response to a change in said second signal;
- multiplying said first signal by said biasing term to thereby establish a third signal which is representative of what the actual flow rate of the crude oil flowing from said desalting process would be if there were no delay between the time said second signal is changed and the time said first signal changes in response to a change in said second signal;
- comparing said third signal and said second signal and establishing a fourth signal responsive to the difference between said second signal and said third signal;
- establishing a fifth signal which is representative of the percentage of said crude oil feed stream which must be provided as said first feed stream to said desalting process to maintain the temperature of said first feed stream after said first feed stream is preheated substantially equal to the temperature of said second feed stream after said second feed stream is preheated;
- multiplying said fourth signal by said fifth signal to establish a sixth signal representative of the required flow rate of said first feed stream;
- and
- manipulating the flow rate of said first feed stream in response to said sixth signal.
Dependencies are inferred from the claim text.