Process
Prepared by:Eng.Control
Basem Lab
Aldaabosh
Experiment #1
Supervisor : Mr. Abdullah Alarosi
Air Pressure Control
Oil Engineering Department
Experiment Name
PH control
INSTRUCTOIN MANUAL
Prepared by : Eng. Basem Aldaabosh
Supervision by : Mr. Abdullah Alarosi
Department of Oil Engineering
Yemeni Academy for Oil and Gas Engineering
General Safety Regulations to be followed in process control lab
1. Wear suitable lab coat, suitable gloves and safety glasses or goggles
should be worn whenever there is potential for contact with particulate
debris, dust, corrosive or toxic materials.
2. Confine long hair and loose clothing when in the laboratory.
3. Know the location of the fire extinguisher, eye wash, safety shower and
first aid kit in your lab and know how to use them.
4. . Determine the potential physical and chemical hazards, and the safety
precautions that apply to your apparatus before beginning.
5. No unauthorized laboratory work should be carried out in the absence
of the instructor. 6. Never leave unattended an experiment that is in
progress.
6. . Review the safety and health hazard data of all chemicals used in the
laboratory.
7. Notify your instructor immediately after any injury, fire or explosion, or
spill.
8. If chemicals come into contact with your skin or eyes, flush
immediately with copious amounts of water and consult with your
instructor.
PH control
Educational Objectives:
1- Establishment of a regulation loop Measure / Actuator / Regulator,
2- Study in enslavement and regulation,
3- Influence of the regulation algorithm by the return to a given instruction following
a perturbation
Technical specifications:
A container of capacity 5 liters,
A variable speed magnetic stirrer,
A pH Probe
Digital controller, RS485 communication board, measurement / reference display / PID control
parameters,
Adaptive,
P, I or PID algorithm
A variable flow peristaltic pump
1 acid storage container,
Analog control by acting on the motor control of the peristaltic pump
Basic injection disruption.
The cabinet can be connected to a recorder for the recovery of regulator power output and measurement
Stainless steel frame, to ask
Options:
Option 1: Acquisition This module consists of: An RS485 / RS232 converter for PC acquisition.
Windows operating software for reading PID parameters, drawing curves, configuring the
remote controller and archiving values.
Option 2: PC type computer
2- Introduction to the Apparatus
This bench allows the study of pH regulation in a container by acting on the injection speed (basic or
acidic liquid) of the pump through a regulator. Different algorithms can be studied.
Nomenclature
V1 Water inlet valve
V2 Water flow regulating valve
V3 Emptying valve
V4 Dropping funnel emptying valve (continuous flow rate interference)
P Variable speed peristaltic pump (0-2 L/h)
A Magnetic stirrer
B1 Reaction vessel (5 L, PVC) (polyvinyl chloride)
B2 Acid Reservoir (250 mL, PE) (polyethylene)
B3 Dropping funnel (250 ml, PP) (polypropylene)
Fl Flow meter (60-600 L/h)
pHT pH transmitter with its probe
Electrical Cabinet with:
Start/stop buttons for the operational unit ( pump and stirrer)
UDC 2500 controller
Pin-head adaptors for analogical signals
Installation and Operation
General Operation:
This bench demonstrates how the pH is controlled in a tank. It consists of a 5 L PVC vessel which
demonstrates how the control process works.
A continuous flow of water is provided through a regulating valve and a flow meter. The regulation is
then based on a dilution effect. The regulation of the flow rate alters the characteristics of the system
and then the working range. Diluted solution is evacuated through the overflow. The system is always
composed of 5 L of solution. An interference is caused by opening the dropping funnel valve and then
supplying a given volume of an alkaline solution in the system.
The other way is to work on a given volume of solution in the vessel (eg 1L). Alkaline solution is
continuously added in the tank thanks to the dropping funnel. Depending on the concentration of this
alkaline solution, the characteristics of the system are then altered. An interference is caused by the
addition of another amount of base or by dilution.
pH probe combined to the transmitter measures pH in the tank. The transmitter converts the 0-14 pH
range into a 4-20 mA analogical signal and sends it to the UDC2500 controller.
The UDC2500 controller is the system’s man-machine interface. It receives the signal from the pH
transmitter and displays it for the user who can then alter the control parameters (set points,
proportional, integral, and derivative actions).
The peristaltic pump is the control loop actuator and is operated by the controller. The pump is
combined to a speed variator: it has a variable speed level between 0 and 100% so a variable flow rate
between 0 and 100% of its nominal flow rate
The electrical cabinet provides the power supply to the pH transmitter, the controller. The magnetic
stirrer and the pump. The front panel contains a series of sockets for accessing the following signals:
The measurements sent by the pH transmitter,
The commands from the controller output.
Each unit includes access to the 4-20 mA measuring circuit loop and a 1-5 V voltage monitor.
Setting up:
The MP 130VE control bench weighs approximately 50 kg and should be moved using suitable
handling equipment.
Check for visible signs of damage before unpacking the equipment and then check that the equipment
is in good condition after unpacking.
Position the control bench next to a 230 V electricity supply, a water inlet and a waste water drain.
Refit the dropping funnel on its rack and put its flexible pipe in the little supports into the tank.
Rinse the pH probe and place it in the vessel. Adjust its support to fix its hight.
Make sure that all the pipe unions have been properly tightened. Close all the manual valves.
The pilot requires a 230 V power supply. The customer is responsible for supplying a suitable plug for
the electricity supply system at the point of use. The plug is to be wired up to the power lead and then
plugged in to the mains electricity supply.
Make sure the 4-20 mA current loops are in place on the electrical cabinet: the red and black banana
plugs of the 4-20 mA input and of the 4-20 mA output are connected by the cables.
Attach one end of a hose to the vessel overflow outlet and the other end to a waste water drain.
Attach one end of a hose to the inlet valve of the pilot and the other end to the water inlet of the room.
The control bench is now ready for use.
Use:
Close all the valves of the installation
Open the room’s main water inlet valve followed by the water inlet valve (V1) of the pilot. Open
progressively V2 to adjust the flow rate and fill the tank.
Close V1 when the tank is full.
Prepare a diluted acid solution and an alkaline one. According to their concentration, system reactivity
will be altered. Classical dilution is about 0.5 to 2 N.
Do not use concentration solution in the installation. Dilute them always before filling the different
containers.
Fill B2 with acid solution.
Fill B3 with the alkaline solution.
Check that the magnetic bar is in the tank.
Turn the main disconnected switch to “I” to switch on the control bench.
Press the “start” button and adjust the speed of the magnetic stirrer by turning the knob on the front
panel of the stirrer.
Use the ▲ and ▼ keys on the UDC 2500 to increase and adjust the output (so the speed and the flow
rate of the pump) in “manual” mode.
The pump is off when output is about 0%.
To work with dilution effect, open V1 and adjust the flow rate with V2. Provided water is continuously
evacuated through the overflow.
To work with permanent base amount, open V4 to adjust the base flow from the dropping funnel.
Working volume can be lower than 5L to be more reactive.
Stay in “manual” mode or press the “man/auto” key on the controller to switch to “automatic” mode, and
then use the ▲ and ▼ keys to adjust the set point level (bottom line on the display).
Watch how the system reacts. You can reach the output parameters (valve opening) by pressing the
“lower/display” key.
Perform a series of different tests to familiarize yourself with the pilot. Then move on to the practical
sessions, using the notes taken during the initial tests that established how the system reacted when the
set points were changed, to determine the PID parameters.
To carry out a range of tests, to create an interference, open suddenly for a given time V4 to add a lot of
base or V1 to dilute the solution.
Work with different concentrations, flows, mixing speed to obtain a wide range of chracteristics and
representative situations.
Shutdown procedure:
Stop the magnetic stirrer.
Press the “STOP” button on the front of the electrical cabinet to stop the system.
Remove B2 and B3 from the pilot, drain them and rinse them.
Fill B2 with water, put it back in its support, place the flexible pipe of the pump in B2.
Press the “START” button and increase the output value to run the pump in order to rinse the flexible
pipe.
When the pipe is cleaned (neutral pH), stop the peristaltic pump.
Open V3 to drain B1. Rinse it using water inlet (V1 and V2). Be careful to the magnetic bar.
When B1 is cleaned (neutral pH), close V1 and V2.
Close the main supply water inlet valve of the room.
Press the “STOP” button on the front of the electrical cabinet to switch off the operational unit.
Turn the main disconnect switch to “0” to cut the power.
Use of the Controller
Press the Setup key to bring up the menu, and keep pressing until the required menu comes up.
Press the key to open the menu
Use the and keys to change the setting.
Press the function key to confirm a setting and move to the next.
You can return to display mode by pressing the lower display key, which also scrolls through the
display options (set point, output, discrepancy).
Functioning modes:
The UDC2500 controller include 2 functioning modes:
Manual: the user directly controls the output signal of the controller between 0 and 100%
Auto: the user specify a control set point and the controller determines the output signal according to
the measure and the equalizer parameters (PID)
The passage from a mode to the other takes place while pressing on the key
Setting of the controller
The PID controller is configured by default with a PID equalizer.
The three actions (proportional, derivative and integral) are accessible by the sequence of the following
keys:
key Display Description
setup TUNING menu Access to the configuration menu of the controller equalizer
parameters.
Function PB Value of the proportional action
Function RATE T Value of the derivate action in minute
Function I MIN Value of the integral action in minute
Setup TUNING menu Return to the main menu
Low display Display Return to the permanent display
The setting of each parameter is possible with the help of the keys and
EXPERIMENTAL PROCEDURE
