k-332

PDVSA N TITLE

REV. DATE DESCRIPTION PAG. REV. APPD. APPD.

APPD.BY DATEDATE

VOLUME 9I

PDVSA, 1983

K332 CONTROL VALVES

FOR APPROVAL

Eliecer Jimnez Alejandro NewskiAUG.94 AUG.94

ENGINEERING SPECIFICATION

AUG.94 L.T.0 8 E.J. A.N.

ENGINEERING DESIGN MANUAL

ESPECIALISTAS

APPD.BY

REVISION DATE


CONTROL VALVES

Page 1

AUG.940

PDVSA K332

Men Principal Indice manual Indice volumen Indice norma

Index

Page

1 SCOPE 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 CODES, STANDARDS AND PRACTICES 3. . . . . . . . . . . . . . . . . . . .

3 DEFINITIONS 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 DESIGN REQUIREMENTS 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 General 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Control Valve Body 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Valve Trim 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Packing 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Actuators 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Positioners 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Electro Pneumatic Convertors 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 Handwheels 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9 Solenoid Valves 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.10 Limit Switches and Valve Position Transmitters 7. . . . . . . . . . . . . . . . . . . . . . 4.11 Volume Boosters 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.12 Air Lock Valves 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.13 Self Acting Regulating Valves 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 SPECIFICATION FORMS 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 INSTALLATION AND COMMISSIONING 8. . . . . . . . . . . . . . . . . . . . . .

7 Q.A. / Q.C. 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

http://www.intevep.pdv.com/santphttp://www.intevep.pdv.com/santp/mid/indice_mid.htmhttp://www.intevep.pdv.com/santp/mid/vol09-1/indice_vol09-1.htm

REVISION DATE


CONTROL VALVES

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AUG.940

PDVSA K332


FOREWORD

This document is the result of several years work by engineers in the petroleum industryof Venezuela (PDVSA).

The recommendations presented in this publication are not intended to supersedeapplicable laws and regulations.

Users of this recommended practice are reminded that no publication of this type can becomplete, nor, can any written document, be substituted for qualifed engineering analysis.

Suggested revisions are invited and should be submitted to:

The manager

PDVSA Engineering Standards,

C/O INTEVEP TENA Divisin,

Apartado 76343

Caracas 1070A

Venezuela


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CONTROL VALVES

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AUG.940

PDVSA K332


1 SCOPEThis section covers PDVSA requirements for the design, specification, installationand commissioning of control valves. All guidelines of the introductionspecification K300 shall also be explicitly followed. These specifications alsoserve for valves used on emergency shut off services but attention is drawn toparagraph 4.1.12 with respect to their use.

2 CODES, STANDARDS AND PRACTICESA.N.S.I. B16.104A.P.I. RP550 Manual on refinery instrument installationF.C.I. 702 Valves calculationsI.S.A. R.P.75.01 to 75.16 Standards for control valvesI.S.A. Handbook of control valves.N.A.C.E.

3 DEFINITIONSAll definitions are listed in specification K300.

4 DESIGN REQUIREMENTS

4.1 General

4.1.1 The control valves shall be air operated.

4.1.2 The body shall be 1inch, carbon steel, flanged 300 lbs. A.N.S.I. minimum exceptfor line sizes smaller than 1inch in which case the appropriate line size body shallbe used. The valve trim shall be 316 stainless steel minimum.

4.1.3 Globe or eccentric rotary plug type valves shall be considered the first option. Thetype of internals viz single seat, double seat, cage, LodB, stellited, etc., shall becarefully selected to suit the particular application.

4.1.4 Ball, flangeless eccentric rotary, flangeless butterfly based on 60 maximumopening, angle, etc. type, of valve shall be used depending on the particularapplication subject to PDVSA approval.

4.1.5 The control valve shall be sized taking into account the minimum, normal andmaximum operating conditions. The finally selected item shall ensure that thevalve operates between 17 and 90 percent opening in accordance with I.S.A. S75.11. The valve shall also operate without any cavitation and produce a noiselevel less than 85 dB.

4.1.6 Valves on hydrogen sulfide and other toxic ambience conditions shall conform tothe appropriate N.A.C.E. specifications.

http://www.intevep.pdv.com/santphttp://www.intevep.pdv.com/santp/mid/indice_mid.htmhttp://www.intevep.pdv.com/santp/mid/vol09-1/indice_vol09-1.htmhttp://www.intevep.pdv.com/~citonline/espanol/cat_norm_inter_frame.htm

REVISION DATE


CONTROL VALVES

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PDVSA K332


4.1.7 The control valve shall be single seated in tight shut off services. The valveleakage class shall be as per ANSI B16.104/FCI standard 702. An extract fromthe standard is listed below. The seating shall be soft seat or metal to metal to suitthe process operating conditions.

Valve Class Maximum Leakage rate

IV 0.01 % of rated valve capacity

V 5 x 104 ml per minute of water per inch of orifice diameter per psi differential

(5 x 10 12 m3 per second of water per mm of orifice diameter per bar differential)

Nominal Port DiameterVI

Milimeters Inches ml per minute Bubbles per minute

25 1 0.15 1

38 1 1/2 0.30 2

51 2 0.45 3

64 2 1/2 0.60 4

76 3 0.90 6

102 4 1.70 11

152 6 4.00 27

203 8 6.75 45

4.1.8 The speed of response of the valve shall be carefully examined to ensurecompliance with the particular application requirements. For eg. valves incompressor surge system; tanker and other pipeline loading systems are requiredto complete their full travel in 1 to 5 seconds. However caution must be exercisedin determining the full open to full close duration to ensure that there are nooccurrences of surge pressures due to sudden valve closures.

4.1.9 Valves with liners on body and trims with vulcanised liners shall be subject tocareful analysis and PDVSA approval.

4.1.10 Bypass valves shall only be installed after a HAZOP study has been performed.Block valves and bypass manifold shall be in accordance with I.S.A. standard RP75.06.

4.1.11 Three way control valves shall be used, subject to PDVSA approval.

4.1.12 Valves used on emergency shut off service applications shall be dedicated solelyto that service only and shall not be used for normal process control purposes.


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PDVSA K332


4.2 Control Valve Body

4.2.1 Control valve body material shall conform to the pipe line specification in whichthey are installed. Carbon steel shall be the minimum. The end connections shallconform with the respective piping specificationRF, RTJ, flat face, etc.

4.2.2 Extended Bonnets shall be provided on fluid operating temperatures above 230Cor below 0C.

4.2.3 Bellows seal bonnets shall be provided on all toxic and hazardous fluids and alsowhen it is necessary to ensure no leakage to atmosphere along the stem in orderto comply with E.P.A. emission regulations.

4.2.4 The use of angle valves shall kept to a minimum and are subject to PDVSAapproval.

4.2.5 The use of welded end connections and items on hydrogen, hydrogen sulfide,cryogenic, pipeline services, etc., shall be subject to careful analysis and PDVSAapproval.

4.2.6 Screwed end connections shall only be used on nonhazardous fluids operatingbelow 50C and 50 P.S.I.G. (3.5 kg/cm2) and body sizes below 1inch.

4.3 Valve Trim

4.3.1 The valve C.V. shall be calculated in accordance with equations in ISA standardS 75.01.

4.3.2 The trim type viz. Single or double seat, low noise, cage, soft seat, cavitationfree,etc., shall be selected to suit the particular application.

4.3.3 The valve characteristic viz. equal percentage, linear, onoff, etc., shall beselected to suit the particular application and process operating data.

4.3.4 The ISA handbook shall be used for selection guidance.

4.3.5 Where the selected valve does not comply with requirements of paragraph 4.1.5consideration shall be given to increase the available pressure drop and as a lastresort to installation of two valves in parallel, one large and one small with splitrange operation.

4.3.6 Butterfly valves shall be sized on maximum 60 operation.

4.3.7 The valve plug shall be solid. The trim material shall be 316 stainless steelminimum. Other materials shall be used to suit the fluid erosion and corrosionproperties. Stellite or harder trim material shall be used on:

Flashing fluids

Fluids with entrained solids

Pressure drops over 14 kg/cm2 G. (200 P.S.I.G).


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4.4 PackingTEFLON shall be used for fluid temperatures upto 230C.

GRAFOIL containing zinc corrosion inhibitor shall be used for all highertemperatures.

4.5 Actuators

4.5.1 The actuator shall be corrosion resistant to marine and any other specified toxicambience.

4.5.2 Pneumatic diaphragm or piston type actuator shall be used to ensure that thevalve:

a. Operates correctly under all specified operating conditions

b. Withstands a pressure drop equal to the maximum upstream pressure

c. Speed of response complies with the process operational requirements.

4.5.3 The shaft stem shall be solid and linked positively to the valve plug. Shaft thrustbearings shall be provided as necessary to ensure smooth operation.

4.5.4 The use of electrohydraulic, electric, hydraulic or digital actuators on specialapplications are subject to PDVSA approval.

4.5.5 The fail position of the actuator on the loss of actuating medium fluid viz. air,hydraulic or electric shall be carefully evaluated and specified to ensure safeoperating condition of the plant and/or equipment.

4.6 Positioners

4.6.1 All valves shall be fitted with pneumatic positioners.

Electropneumatic positioners shall be used on all applications where thepositioner operation is not affected by line vibrations.

Exceptions are onoff valves and certain flow or liquid pressure loops where theadded positioner gain could lead to instability. These exceptions are subject toPDVSA approval.

4.6.2 The input signal shall be 3 to 15 P.S.I.G. The output shall suit the selected actuator.

4.6.3 Positioners shall be complete with bypass, input, output and air supply gaugesand an air filter set.

4.6.4 The positioner and all accessories shall be corrosion resistant to marineatmosphere. The tubing between positioner and actuator shall be P.V.C. covered316 stainless steel.


REVISION DATE


CONTROL VALVES

Page 7

AUG.940

PDVSA K332


4.7 Electro Pneumatic Convertors

4.7.1 When specified they shall be suitable for specified 420 or 412 or 1220, m.A.D.C. input operation. The output shall be 315 P.S.I.G. The convertor shall becertified intrinsically safe.

4.7.2 The convertor and all accessories shall be corrosion resistant to marineatmosphere.

4.7.3 The convertor shall be mounted on a suitable vibration free bracket.

4.8 Handwheels

4.8.1 These shall be supplied when specified. They shall be declutchable type with aclear indication of the neutral position.

4.8.2 The handwheel mechanism shall not increase frictional load of the actuator andoperable even against the specified maximum differential pressure.

4.8.3 Clutch/linkage mechanisms on rotary valves shall be designed such that thecontrol of the valve position is not lost when engaging the handwheel.

4.8.4 Hand wheel shall be specified only after a HAZOP study has been performed.

4.9 Solenoid Valves

4.9.1 When specified they shall be installed in the output tubing between the positionerand the valve actuator.

4.9.2 They shall be 3way, 1/4 N.P.T.F. 316 stainless steel body type with resilient seatsand 24 volts D.C hermetically potted coil suitable for operation at 50 C ambienttemperature. They shall be suitable for operation in intrinsically safe circuits andprovided with a manual reset lever when specified.

4.9.3 If an airlock valve is specified for the system the solenoid valve shall be installedbetween the air lock valve and the actuator.

4.10 Limit Switches and Valve Position Transmitters

4.10.1 When specified they shall be linked directly to the valve stem.

4.10.2 The limit switches shall be snap acting hermetically sealed microswitch and ratedfor operation at 1 amp. at 24 volts D.C.

4.10.3 The transmitter output shall be 4 to 20 m.A. D.C.

4.10.4 All electrical items shall be certified for use in intrinsically safe circuits andcorrosion resistant to marine atmosphere.


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AUG.940

PDVSA K332


4.11 Volume Boosters

4.11.1 Volume boosters shall be installed, when necessary to increase speed ofresponse of the control valve.

4.11.2 The booster shall be installed in the output tubing between the positioner and thevalve actuator.

4.12 Air Lock Valves

4.12.1 When specified the air lock valve shall be installed between the positioner and theactuator.

4.12.2 The air supply for the lock valve shall be the same as for the valve positioner.

4.12.3 The item shall be corrosion resistant to marine atmosphere and the setting shallbe tamperproof.

4.13 Self Acting Regulating Valves

4.13.1 They shall be used on inert services such as water, air or nitrogen and noncriticalservices such as fuel gas to pilot burners.

4.13.2 All actuators shall be capable of withstanding the maximum specified upstreampressure.

4.13.3 Body and trim shall conform with guidelines in this specification.

5 SPECIFICATION FORMS

FORM No. TITLE20.50 Control valves

20.50X On/off valves with positive closure

20.51 Self acting pressure regulator

20.52 Self acting temperature regulator

The forms are included at the end of this specification.

6 INSTALLATION AND COMMISSIONINGAll installation and commissioning shall be performed in accordance with projectdrawings and specifications.

7 Q.A. / Q.C.All items shall conform with the procedures in specification K369.


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