Model-Free Adaptive Control
of Oil Separators with ControlWave™
|• Feedback/Feedforward MFAs control of oil
levels to balance the material flow in multiple
||• To ensure that all capacity in a 3-phase
crude oil separator is being used so that the process
throughput is maximized without any trips occurring.
|• Robust control of water levels to maximize
vessel capacity and prevent leakage.
||• Automatically control critical oil level,
water level, and pressure loops under all operating
conditions and eliminate the need to manually re-tune
the controller parameters.
|• Nonlinear MFA control of
gas pressure to handle slugs and reduce gas waste.
||• Combining Bristol Babcock's ControlWave
with CyboSoft’s MFA technology delivers quick
Control & Optimization Using Embedded MFA Controllers
Process: Whether onshore
or offshore, a 3-phase oil separator train consists
of 2 separator vessels with or without a slug catcher.
Crude oil consisting of water, oil, and gas is separated
through the system.
Control Problems: Each ves-sel is typically
controlled as a standalone unit. There are instances
where a high level trip in one of the vessels has occurred
while there is spare capacity in the other vessel. Also,
the gas pressure loop is nonlinear in nature and a random
slug can cause the pressure loop to swing resulting
in frequent ignition of excessive gas.
Solution: This is a combined control
and optimization problem. CyboSoft offers an effective
solu-tion for controlling critical level and pressure
loops and maximizing the separation capacity.
Water Level Control: Robust MFA controllers
are used to control the Water Levels. This allows a
lower setpoint setting leaving more storage room for
the Oil Level. A lower bound on the Water Level PV prevents
the level from drop-ping too low which might cause oil
Pressure Control: Nonlinear characterization
of the pressure loops is not required to use the nonlinear
MFA controllers. They can effectively deal with gas
loop nonlinearity and slug problems with easy configuration.
Oil Level Control: Feed-back/Feedforward
MFA controllers are used to control the oil levels in
a multivariable control fashion. The respective oil
levels can be coordinated by simultaneously manipulating
the related oil valves to prevent too high an oil level
in one vessel while there is still storage room in others.
This special MFA can balance the oil levels for both
vessels to maximize the vessel capacity usage.
Conclusion: This solution is delivered
using Bristol Babcock's ControlWave Hybrid controller,
which has a Class I, Div 2 rating and can be used on
oil platforms. Since no process models are needed, commissioning
and maintenance of the system is simple with guaranteed