The Three-Phase Separator offers an interactive measurement and control
experience to build competency in the crude oil separation process. It allows
future operators, instrumentation technicians, and engineers to develop
relevant skills to successfully perform installation, operation, troubleshooting,
and maintenance tasks. The training system is a scaled-down version of a
real horizontal, three-phase separator that demonstrates the fundamentals of
oil separation, using water and mineral oil, with air as the gas medium to
emulate crude oil. Experiments are performed using industrial smart
instrumentation devices and control components to provide first-hand
experience with the HART communication protocol, as well as Rockwell Automation
and Endress+Hauser technologies. The inlet zone is where the emulsion is
created. The deflection plate is the first step in the separation process: the
emulsion goes down in flows under the plate, then passes through the coalescing
plates. The emulsion layer is quite thick at the beginning of the process and its
thickness decreases as it goes through the separation process. Components of the
emulsion are eventually completely separated. Due to gravity, water will
remain below the oil to be drained from the vessel, and oil will overflow to the
other section after passing over an overflow plate.
The pneumatic controller will actuate the valve, and flow rate will be measured.
Students interact with the system through an HMI for data acquisition and
alarm management. The system is monitored
using the PlantPAx Distributed
Control System. The HMI displays the instruments and allows the monitoring of
output flow rates of air, water and gas, as well as temperature. It is possible to
insert faults, as well as change the operating mode from automatic to manual,
and the measuring units from metric to imperial. The HMI can also display a
Piping and Instrumentation Diagram (P&ID) of the system. The piping and
Instrumentation Diagram displays and identifies the instruments,
such as flowmeters for water, oil, and gas, and measuring devices for oil and water
levels. Alarm management is also possible here. Housed in the monitoring unit, the
PLC monitors processes and instruments and sends information to the HMI. Each
instrument can be quickly and easily connected to the monitoring unit.
Two pressure regulators feed the system with air. This one on the left feeds the
separator vessel and the second one feeds to level controllers. This level
controller controls the oil level; the second controller is used to control the
oil and water interface level. Oil and water interface level can be adjusted
using the screws of the appropriate mount. These two small valves can be used
to fault the controllers. Other valves are hidden throughout the system to
induce several faults in order to test students' troubleshooting skills.
Gas flows out of the vessel through this tube. Flow rate is measured by an orifice
plate using the differential pressure across the pressure tappings. Gas will
then flow through a backpressure regulator. This device maintains a
constant pressure in the separator vessel to make sure the pressure does
not exceed limits. The pressure safety valve also controls the pressure inside
the vessel for enhanced safety. Three vibrating forks are located under the
vessel and detect low levels of oil and water in the vessel. Vibrating forks
send signals to their respective connection box. Connection boxes are
equipped with false switches to induce faults to the forks. The system includes
two centrifugal pumps equipped with three-phase motors. One pumps water from
the water tank; the other pumps oil out of the smaller oil tank. The pumps are
controlled by the pump controlling unit. Two Allen-Bradley variable-frequency
drives allow changing flow rates and pressure. The unit also features an
emergency stop button, operating light signals,
and a main disconnect switch. To start the pumps,
the students use the keyboards on the control unit, and it is important that
they enter the frequency. Pumps send water and oil to the three rotameters:
one for water, one for oil, and one for gas. The rotameters allow students
to control the proportion of water, oil, and gas in the crude oil emulation
mixture. Water, oil, and air are sent through this tube here. It is possible to
send this mixture to the inlet zone of the separator as-is. It is also possible
to divert the mixture to the inline mixer by turning these handles to blend
the fluids. The large clear acrylic vessel and clear PVC piping allow for
observation of flows and of internal components during operation. It includes
typical elements of a three-phase separator, such as a diverter plate, a
perforated baffle plate, coalescing plates, a weir plate, and a demister pad.
Here we can see the level of oil and water. Oil overflows to this side of the
vessel. Water flows out of the vessel from the bottom. Gas flows to this upper
part of the vessel to be expelled. The demister pad, located in this zone, will filter
any remaining droplets of oil or water. The vibrating fork here detects if the
oil level becomes too high. The pressure gauge indicates the pressure in the
vessel. There is also a pressure reading point connected to a transmitter. The
multiparameter radar level transmitter allows for the measurement of oil and
water levels in the separator. This rupture disc is a pressure relief
device that protects the system against overpressurization.
As previously mentioned, the signals of the oil and water levels are sent
through this cable to this transmitter, so that we can read the levels. This tube
sends information regarding the vessel pressure to this transmitter, which
displays the correct value. The other transmitter is a differential
transmitter that will measure the gas flow rate is measured by the backplate
orifice. Each transmitter is equipped with a connection box that integrates a
switch for fault insertion. Students can also learn to configure
transmitters manually using these keys and menus. This optional transmitter
displays temperature and is wired to a thermocouple located under the vessel.
The water is drained out of the vessel from the bottom. A turbine flow meter
measures outflow rate. The oil that overflowed in the right-hand part of the
separator also needs to be drained out. The oil outflow is also measured by a
turbine flowmeter. The turbine flowmeter for water can be replaced with an
optional magnetic flowmeter like this one for oil. It can be replaced with an
optional Coriolis flowmeter. Water and oil outflow rates are controlled by
pneumatic control valves, actuated by level controllers located in the black
box at the back of the separator. For manual control of the outflow rate, it is
also possible to manually bypass the pneumatic control valves using bypass valves.
For more information about the Three-Phase Separator, please contact
your Festo didactic sales representative or visit our website.