CLD 20202 Exp 1-Control Valve

UNIVERSITI KUALA LUMPURMALAYSIAN INSTITUTE OF CHEMICAL & BIOENGINEERING TECHNOLOGY

CLD 20202PROCESS INSTRUMENTATION

DIPLOMA OF CHEMICAL ENGINEERING TECHNOLOGY

EXPERIMENT 1Control Valve Characteristic

EXPERIMENT 1

Experiment 1: Control Valve Characteristics

CONTROL VALVE CHARACTERISTICS

1.0 EXPERIMENTS PROCEDURE

1.1 Plant Start-up Procedures

1. Tanks T1 and T2 should be filled with water almost up to the level of their overflow pipes.

2. Control valves FCVL, FCVE and FCVQ are all air-to-open (ATO).

3. Open the instrument air supply to operate the control valve system Check that the pressure is set in accordance to the pressure indicated at

the air pressure regulator (AS) If there is any condensed water at the air regulator, purge it by opening its

bottom bleed valve.

4. Turn ON the main power supply switch at the front cubicle.

5. Closed the drain valves of tanks T1 and T2.

5. The control valves can only be selectively operated ONE at a time from the flow indicator controller, FIC.

1.2 Experiment 1 (Control Valve Running with Small Pump)

1.2.1 Linear Valve Operation

1. Open the manual valves: BVS, MVS, MVL1 and MVL2.

2. Fully close the following manual valves: MVB, MVE1, MVQ1, and BVL.

3. Turn all the selector switches (SS1, SS2 and SS3) to position 1.

4. Controller FIC must be in manual (M) mode with its MV=100%. Make sure the chart drive of the recorder FDPZR is running. Otherwise, press it’s ‘STOP’ pushbutton for a few seconds with its front swing cover opened.

5. Starts pump PS and verify its flow at the discharge of pipeline PLL into tank T2. Fully close the pump by-pass manual valve BVS for maximum available flow through the control valve FCVL and the pipeline PLL using the smaller pump PS.

6. Refer to the Table AL and note the following readings at the recorder FDPZR and the pressure gauge PS.

Channel 1 (USGPM)


Blue pointer/trace (flow rate) Red pointer/trace Green pointer/trace

7. Change the MV = 80% and repeat the procedure to change the MV value.

8. Stop the small pump, PS.

1.2.2 Equal Percentage (%) Valve Operation

1. Open the manual valves: BVS, MVS, MVE1 and MVE2.

2. Fully close the following manual valves: MVB, MVL1, MVQ1, and BVE.



5. Starts pump PS and verify its flow at the discharge of pipeline PLE into tank T2. Fully close the pump by-pass manual valve BVS for maximum available flow through the control valve FCVE and the pipeline PLE using the smaller pump PS.

6. Refer to the Table AE and note the following readings at the recorder FDPZR and the pressure gauge PS.

Channel 1 (USGPM) Blue pointer/trace (flow rate) Red pointer/trace Green pointer/trace



1.2.3 Quick Opening Valve Operation

1. Open the manual valves: BVS, MVS, MVQ1 and MVQ2.

2. Fully close the following manual valves: MVB, MVL1, MVE1, and BVQ.




5. Starts pump PS and verify its flow at the discharge of pipeline PLQ into tank T2. Fully close the pump by-pass manual valve BVS for maximum available flow through the control valve FCVQ and the pipeline PLQ using the smaller pump PS.

6. Refer to the Table AQ and note the following readings at the recorder FDPZR and the pressure gauge PS.




1.3 Experiment 2 (Control Valve Running with Big Pump)

1.3.1 Linear Valve Operation

1. Open the manual valves: BVB, MVB, MVL1 and MVL2.

2. Fully close the following manual valves: MVS, MVE1, MVQ1, and BVL.



5. Starts big pump, PB and verify its flow at the discharge of pipeline PLL into tank T2. Fully close the pump by-pass manual valve BVB for maximum available flow through the control valve FCVL and the pipeline PLL using the big pump PB.

6. Refer to the Table AL and note the following readings at the recorder FDPZR and the pressure gauge PS.



8. Stop the big pump, PB.1.3.2 Equal Percentage (%) Valve Operation

1. Open the manual valves: BVB, MVB, MVE1 and MVE2.


2. Fully close the following manual valves: MVS, MVL1, MVQ1, and BVE.



5. Starts big pump, PB and verify its flow at the discharge of pipeline PLE into tank T2. Fully close the pump by-pass manual valve BVB for maximum available flow through the control valve FCVE and the pipeline PLE using the big pump PB.

6. Refer to the Table AE and note the following readings at the recorder FDPZR and the pressure gauge PS.



8. Stop the big pump, PB.

1.3.3 Quick Opening Valve Operation

1. Open the manual valves: BVB, MVB, MVQ1 and MVQ2.

2. Fully close the following manual valves: MVS, MVL1, MVE1, and BVQ.



5. Starts big pump, PB and verify its flow at the discharge of pipeline PLQ into tank T2. Fully close the pump by-pass manual valve BVB for maximum available flow through the control valve FCVQ and the pipeline PLQ using the big pump PB.

6. Refer to the Table AQ and note the following readings at the recorder FDPZR and the pressure gauge PS.



7. Change the MV = 80% and repeat the procedure to change the MV value. Stop the big pump, PB.

1.4 Shut-down Checklist

1. Switch FIC to manual (M) mode and set it to its default set point (SV), output MV and PID valves.

2. Switch off all of the pumps. Press the recorder ‘STOP’ pushbutton for a few seconds to stop the chart drive. The recorder will display ‘Record Stop’.

3. Turn off the external air supply valve to the model plant. It is not necessary to turn off the individual air regulator (marked IAS).

4. Turn all of the selector switches (SS1, SS2 and SS3) back to position 1.Switch off the main power supply at the front cubicle.


2.0 RESULTSTABLE AL: Pump PS with FCVL for Experiment 1

1 2 3 4 5 6 7 8 9 10 11Adjust FIC

manual Output MV

%

Flowrate (F) Valve Opening(Z or m)

Valve Pressure Drop (DPv)

Pump Discharge

Pressure PGS

(Psig)

Calculate the following ratio

Channel 1(BL)

USGPM

Blue pointer or trace

%

Channel 2(RD)

%

Red pointer or trace

%

Channel 3(GN)

psi

Green pointer or trace

%

%

DPv/PGS

Cv/CVmax

100.0 Fmax(L)80.060.050.030.020.010.05.00.0

0.05.010.020.030.050.060.080.0

100.0 Fmax(L)Comments:


TABLE AE: Pump PS with FCVE for Experiment 1

1 2 3 4 5 6 7 8 9 10 11Adjust FIC

manual Output MV

%



Pump Discharge Pressure

PGS

(Psig)


Channel 1(BL)

USGPM


%

Channel 2(RD)

%


%

Channel 3(GN)

psi


%

%

DPv/PGS Cv/CVmax

100.0 Fmax(L)80.060.050.030.020.010.05.00.0

0.05.010.020.030.050.060.080.0



TABLE AQ: Pump PS with FCVQ for Experiment 1

1 2 3 4 5 6 7 8 9 10 11Adjust FIC

manual Output MV

%



Pump Discharge

Pressure PGS

(Psig)


Channel 1(BL)

USGPM


%

Channel 2(RD)

%


%

Channel 3(GN)

psi


%

%

DPv/PGS Cv/CVmax

100.0 Fmax(L)80.060.050.030.020.010.05.00.0

0.05.010.020.030.050.060.080.0



TABLE BL: Pump PB with FCVL for Experiment 2

1 2 3 4 5 6 7 8 9 10 11Adjust FIC

manual Output MV

%



Pump Discharge

Pressure PGB

(Psig)


Channel 1(BL)

USGPM


%

Channel 2(RD)

%


%

Channel 3(GN)

psi


%

%

DPv/PGS Cv/CVmax

100.0 Fmax(L)80.060.050.030.020.010.05.00.0

0.05.010.020.030.050.060.080.0



TABLE BE: Pump PB with FCVE for Experiment 2

1 2 3 4 5 6 7 8 9 10 11Adjust FIC

manual Output MV

%



Pump Discharge

Pressure PGB

(Psig)


Channel 1(BL)

USGPM


%

Channel 2(RD)

%


%

Channel 3(GN)

psi


%

%

DPv/PGS Cv/CVmax

100.0 Fmax(L)80.060.050.030.020.010.05.00.0

0.05.010.020.030.050.060.080.0



TABLE BQ: Pump PB with FCVQ for Experiment 2

1 2 3 4 5 6 7 8 9 10 11Adjust FIC

manual Output MV

%



Pump Discharge Pressure

PGB

(Psig)


Channel 1(BL)

USGPM


%

Channel 2(RD)

%


%

Channel 3(GN)

psi


%

%

DPv/PGS Cv/CVmax

100.0 Fmax(L)80.060.050.030.020.010.05.00.0

0.05.010.020.030.050.060.080.0




3.0 CALCULATION

Where F = Flowrate in USGPMSG = Liquid Specific Gravity water SG at 60 F is 1.0) DPv = Pressure drop across the control valve in psi

4.0 QUESTIONS

1. What is control valve Cv?

2. What is control valve rangebility?

3. How is the control valve characteristics normally illustrated graphically?

4. What is the effect of (DPv)/(DPs) on the inherent control valve characteristics?

5. Compare the characteristic curves of FCVL, FCVE and FCVQ obtained in Experiment 1 with those in Experiment 2. Is the deviation from the inherent characteristics more serious in Experiment 2 than in Experiment 1? Please comment on the DPv and DPs in each case.

6. Why is it important to know the control valve characteristics? Which is important finally in an operating control loop, the installed or inherent valve characteristic?

5.0 REFERENCE

1. Experiment Manual WCV911, QDR Marketing Sdn. Bhd.



Date post:	29-Nov-2015
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CLD 20202 Exp 1-Control Valve

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