Microsoft PowerPoint - Anti-surge Control Valve_Oil & Gas Refinery
SEVERN GLOCON(Control Valve) , / EPC
2009 2011 .
S&T S&T International Co.
(Stanley Park) (President, P.E.) S&T International Co. Mobile : +82(0)10-3840-0721 Tel/ Fax : +82(0)2-400-8039 E-mail : stanley.park@daum.net
Compressor Systems
Ø Leakage across the valve
Ø Wear of the valve trim
Ø Clogging/sticking of the valve
Ø Inadequate response time
Ø Instability in valve operation
Gas Compressor surge pressure balance Recycle(Anti-surge) valve Blow-down to Flare
valve . , Recycle valve(Anti-surge) compressor suction balance
Blow-down Gas to Flare valve compressor pipeline (, : Kick-Back)
. pipeline compressor surge .
Gas Plant Gas Compressor , Compressor Anti-surge pipeline Gas-to-
Flare compressor surge compressor .
Compressor ,
. Engineering A-S Valve Gas to Flare valve severe service
inquiry , Anti-surge valve , .
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Seat leakage class V , class IV class V IV Driver
Electric Motor Gas Turbine, Steam Turbine .
Gas compressor class V class IV compressor
Class IV . delta P Metal-to-Metal seat class V
class IV .
oil (high delta P) trim .
(carbonized) hydrocarbon , Black powder trim hole path cage hole , tar
plug . sticky black powder hole plug ,
. Dry Gas Black powder .
chemical bio-particle trim .
trim design, Anti-surge valve .
Compressor surge protection system, control recycle .
Surge protection system process upset process recycling compressor surge
. CCC controller input 10- 15ms . controller output signal 3 cycle
40ms, .
Stroke surge . surge compressor shutdown .
Compressor compressor controller surge protection package( 25µm 75µm axial displacement :
0.001≤ 0.003≤) axial shaft trip .
Compressor Costs Over a 30 Year Life
Ø Costs are for a 20,000
HP compressor
$18,500/hour in lost sales
- Seal replacement : $120,000
- Bearing service : $100,000
- New rotor assembly : $2,000,000
2 (15MW) Compressor 30 2 7 3 (3,150) (
4 , 9 , 2 6 ).
Compressor 18,500, 222 30
.
Compressor Surging
Ø Actual flow reversal occurs within 2 to 5 sec
Ø Surging cycles at 2 to 3 cycles/sec.
Ø Compressor vibration occurs
Ø Surging may not be readily detected by conventional instruments
Ø Most compressors surge at low energy during start-up
Ø Unstable flow & pressure
Ø Increased seal clearance & leakage
Ø Lower efficiency
Ø Reduced compressor life
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Centrifugal Compressor
. Centrifugal Compressor Casing Impeller ,
Impeller Blade . , , diffusion
. rotating shaft impeller curve blade ,
impeller diffusion(diffuser ) .
compressor 3,000rpm 14,000rpm
. Surge compressor head , Compressor surge
head , . Centrifugal compressor .

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(low mass flow) compressor .
(low mass flow) discharge line .
,
. Gas Compressor Surge . , Gas
Compressor Impeller head Impeller
. compressor surge line . , start-up/emergency shutdown
surge line . surge line impeller diffuser stall()
. discharge pressure suction discharge
.

()
.
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A : (Design Point ) , IGV(Inlet Guide Vane) ,
. .
B : (System Resistance) , .
E : , .
C : , Surge , . 'C' Surge
(Surge Point ) , () Surge .
Surge
, Surge (Control) .
Surge , ,
() .
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, .
C → D : , 0(Zero) D .
D → E : , ( → ), E . ,
, .
E → C : C .
C -> D 1 , 5 Surge 1 , 5 (Surge 5)
.
Surge , (Unloading) , BOV(Blow off Valve) Anti-surge ,
.
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. A
, Surge (Surge Line)
X () ,
Y ( ) .
Surge
IGV(Inlet Guide Vane)
, Surge
IGV (IGV Minimum
Position) .
Surge (Volume flow) (Pressure ratio)
Surge ,
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Typical Compressor Surge Control System Layout with Single Recycle Valve
Surge control system application , application
.
centrifugal compressor surge system application compressor pipeline compressor
. Surge pipeline , surge line (, compressor
range ). surge , surge margin .
, , application methane(75-95%)
heavy hydrocarbon N2 CO2 . compressor ,
pipeline () .
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Re-Injection Application Compressor production field , application field discharge pressure (field ). well , surge line head (
) . slug surge control system
, discharge (3,000psig=200barg ),
compressor . application , . Suction process .
Storage and Withdrawal Application Compressor field reservoir . Suction (
, ). field
, . application surge control system process control , . recycle control signal pipeline application .
Gas Gathering Application processing pipeline mixture . application
dehydration level, separation filtration . piping volume
modeling . field mixture compressor
head vs. speed curve . application . discharge
pipeline 3,000psig(200barg) .
High Pressure/Process Compression Application compressor application . application
3,000-5,000psig(200-340barg) . Process plant compressor process (LNG , , hydrocarbon NGL
removal process) , head , process .
Surge control system surge compressor surge
. Compressor Anti-surge valve control compressor /
. 2~5 surge 2~3/sec .
. seal, bearing, impeller shaft
seal leak compressor .
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with rated capacity of 1.8 to 2.2 times normal flow
Ø Overcapacity is required for:
- Safety margin in case valve opens slowly
- Additional venting of the downstream line
Sizing Compress or Recycled Valves Rated 1.8~2.2 normal ( stem travel 55% ), .
, pipeline Blow-down
vent . 100%
compressor discharge suction recycle
80% 120% margin
blow-down vent valve
.
Valve Characterization for Compressor Recycle
Surging recycle compressor suction/discharge pressure
multi-path, multi-stage trim, surge line suction delta P
single stage trim .
Characterized Valve Trim
Ø MLT/CC trim for low noise, velocity & energy control
Ø Long valve stroke permits characterization of the disk stack or use of high capacity trims
Ø Characterized trim for good low flow control & high flow capacity protection
Ø Metal seal bonnet design retains the MLT stack in compression
Ø Internal stops in the valve to absorb impact load
Ø Expanded outlet to handle gas expansion
Ø Balanced trim for running forces
Ø High seat loading for tight shutoff
Control Valve for Compressor Recycle
Severn Glocon Severe Service
MLT/CC trim stroke disk stack
characterized curve .
characterized trim
. Metal seat MLT stack
, seal impact .
outlet force
balanced trim , Tight shutoff
loading seat .
Ø Sizing for normal flow must be considered as potentially extended duty
Ø Sizing for emergency flow can be considered as intermittent duty
Ø Local HSE guidelines for worker exposure to noise
Ø Consideration for noise & damage to the downstream pipe system
Ø Consideration for potential damage to the valve or components from vibration
normal flow
, emergency flow
. (HSE:
Health Safety Executive)
pipeline ,
pipeline .
Noise Considerations in Compressor Recycle Valve Sizing
0 10 20 30 40 50 60 70 80 90
100
0 10 20 30 40 50 60 70 80 90 100
% Flow
% Stroke
Disk Stack Characterization
Ø Linear stack The trim has a stack or cages with the same
number and size of holes or passages on
the full length of travel.
- Flow is directly proportional to the valve’s
stroke at constant differential pressure
Ø Characterized stack - All disks are not the same
- Provides precise variable flow versus
pressure drop over the full range of the
valve
Ø Application of high unit loading to valve seat surfaces
Ø Finesse lapping of seating surfaces
Ø Use balanced trims to reduced hydraulic forces
Ø Use soft seats to minimize loading requirements
Ø Pressurized seat designs
Linear stack cage trim
stroke delta P stroke
, Characterized stack disk
stroke
, . Seat
seat force
balance trim soft seat
pressurized seat
Methods to Obtain Shutoff
Ø FCI-70
psi
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Ø FCI-70
(per MSS-SP-61)
ISA Guideline .
( Severe Service Valve Article )
Test media air ,

air
.
, Metal to Metal seat
Class V Balance seal, Seat ring
leak . stellated
Stem/plug stellited Seat ring ,
Bonnet flange Body flange
.
Ø Double acting “low volume” spring-less pneumatic cylinder for
- High force levels - High stiffness - Minimum air volumes for fast response - Wrought end plates, steel tie rods for impact
loading
- Surge protection opening (modulate) : 2 sec
- Delay/lag time : 0.2 to 0.4 sec max.
Ø Closing response times can be slower depending on
surge control design
- Modulating : 3 sec
oscillation
Double acting pneumatic piston actuator thrust force, , air ,
steel .
open , trip 1~2, surge protection 2 opening , delay/lag time 0.2~0.4
. closing time surge control design modulating mode 3 .
overshoot quick correction (oscillation) .
Hot Gas Bypass
Ø Severn Glocon has supplied many hundreds of high speed response compressor recycle valves.
Ø The total number of hot gas bypass valves is a small portion of the above number.
Ø Hot gas bypass normally involve on/off function for compressor protection in the event of power loss.
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Hot gas bypass Anti-surge . ,
compressor start-up shutdown Anti-surge Cv surge Anti-surge
. cooler Anti-surge valve discharge
suction recycle . quick open . quick open Cv
dynamic simulation opening characteristic .
Closing time closing time (Aramco opening time 3) GE compressor closing
time 12 . surge compressor compressor
compressor closing time compressor , compressor
impeller . shaft displacement ( 25µm 75µm axial
displacement: 0.001≤ 0.003≤) compressor trip .
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Overshoot 2.5% GE 3.0% , modulating downstream
throttling overshoot surge quick opening Anti-surge
valve compressor GE 3.0% overshoot .
Anti-surge Response time vs. Stroke time 2 Anti-surge control system ,
Stroke time : Actuator piston stroke length ( )
.
Response time : system compressor controller
positioner actuator .
Compressor emergency shutdown valve kick-back compressor surge
controller positioner . surge
(2 1 ) . Compressor
compressor . positioner compressor
. Response time control logic opening response time closing 3
program . Response time controller Anti-surge
control system actuator stroke speed controller response
time surge compressor trip .
controller (CCC- USA, ) .
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Turbo Expander( Heavy Hydro-carbon gas
) Compressor Expander 10,000rpm( compressor 5,000- 7,000rpm )
Expander Compressor A/S closing time fast stroke .
Aramco Shaybah Gas Package #2 Anti-surge 2 , Turbo Expander
Joule Thomson Bypass Compressor A/S CCC Controller control mode
Gas/ turbine, motor compressor .
Expansion brings 2 positive effects
through expansion by 2 phase turbine
♦ Power production
drop due to less heat produced by
friction
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Surge Kick-back () Gas-to-Flare Blow-down Valve
Straight Pipeline Length for Anti-surge Valve pipeline surge compressor .
pipeline inlet flange diameter 2~3
.
pipeline compressor suction recycle ,
. . pipe
outlet diameter 4 .
S&T International Co. Hot Has Bypass Valve Application
1. : Compressor
.
2. Dehydration Process : LNG Process Natural Gas Acid Propane Unit