Embed Size (px)
DESCRIPTION
probs
Citation preview
8/4/13 Chemical & Process Technology: Problems Caused by Two Phase Gas-Liquid Flow
webwormcpt.blogspot.com/2010/02/problems-caused-by-two-phase-gas-liquid.html 1/4
FOLLOW ME
Enter your email
address:
Subscribe
SUPPORT This Site
Chemical & Process TechnologyA place to share knowledge, lesson learnt...
HOME ARCHIVE LINK FREE MAGAZINES
Hot Posts
FREE Info
Free Newsletter
Free Magazine
Latest Posts
CE Feb 2010
17 Ways to ReduceLikelihood of PumpCavitation
Facts about Erosion& Erosion-Corrosion
Erosion & Erosion -Corrosion
Control ValveCavitation Damageand Solutions
CE Digital Issue forJan 2010
Assess PotentialPiping Failure Due toValve Quick...
QuickDetermination PipeSupport StiffnessLevel a...
Construction QualityProgram in Oil &Gas Industry...
Assess PotentialPiping Failure Due toCV, BDV & P...
Links
Chem & Proc tech
Oil & Gas tech
Heat Exch tech
Gen Tech
Webworm DC
Chemical andProcessEngineering
ChemicalEngineering World
Smart ProcessDesign
ChEng
Visitors
(Since Apr. 21,2007)
6 users online
Archives
Search
Web Chem & Proc Tech
CHEM & PROC TECHOIL & GAS TECH
HEAT & EXCH TECHGEN TECH
Problems Caused by Two Phase Gas-Liquid Flow
Saturday, February 27, 2010
Two phase gas liquid flow is commonly occur in any oil & gas production and processingsystem. Several flow patterns can occur in two phase gas liquid flow. There are Bubbleflow (with minimum vapor bubble), Plug flow, Stratified flow, Wavy flow, Slug flow, Annularflow and Mist/Dispersed flow (with minimum liquid droplet). See following images.
► Natural Gas ► Flow Valve ► Gas Cooling ► Liquid Gas
equipment. Regardless of vessel/column/drum/tankdesigned in accordance to any pressure vessel codee.g. ASME, JIS, BS, GB, etc,...
How to apply valve equation in HYSYS Depressuring ?High pressure and moderate/low temperatureoperation are common in oil and gas industry. Highpressure system with large vessels will lead to largeinventory and it significantly increases hazardous level
8/4/13 Chemical & Process Technology: Problems Caused by Two Phase Gas-Liquid Flow
webwormcpt.blogspot.com/2010/02/problems-caused-by-two-phase-gas-liquid.html 2/4
Recommended Jobs
Process Chemist
Miri - Shell
Production Technology
Consultant
Miri - Shell
Senior Materials and Corrosion
Miri - Shell
Petrophysicts Discipline Lead
Miri - Shell
Disc Lead Prod Technology
(FEPD
Miri - Shell
Enter search terms... Go
www.indeed.com
April 2007
May 2007
June 2007
July 2007
August 2007
September 2007
October 2007
November 2007
December 2007
January 2008
February 2008
March 2008
April 2008
May 2008
June 2008
July 2008
August 2008
September 2008
October 2008
November 2008
December 2008
January 2009
February 2009
March 2009
April 2009
May 2009
June 2009
July 2009
August 2009
September 2009
October 2009
November 2009
December 2009
January 2010
February 2010
March 2010
April 2010
May 2010
June 2010
July 2010
August 2010
September 2010
October 2010
November 2010
December 2011
July 2012
August 2012
Obvious Location Present of two phase gas liquid may be obvious and be easily identified duringdevelopment phase. Typical example are Full-Well-Stream (FWS) production whichpossibly producing hydrocarbon in gas and liquid form. Formation water, condensedwater, mercury, and injected chemical (e.g. corrosion inhibitor, hydrate inhibitor, etc) inliquid form, wax in slurry form and sand in solid form may also present in the FWS, whichtypically result complicated multiphase form. Partial stabilized condensate travel longdistance experience high pressure drop lead to vaporization. Vapor travel long distanceexperience ambient and J-T (isenthalpic process) cooling lead to condensation. Hotsaturated vapor is cooled by air cooler or heat exchanger results condensation, vapor orliquid passing through turbine experience isentropic process, etc. These streams areobvious and can be easily identified in process simulation. Generally example are :
Full Well Stream (FWS)Partial stabilized condensate with long pipelineSaturated vapor with long pipelineLiquid stream from separator passing a level control valveDownstream of Air cooler / Heat exchangerTurbine outletHot fluid mix with cool fluid continuously
Recommended :Subscribes to FREE Hydrocarbon Processing
Non-obvious Location There are certain stream may be not so obvious and may not beeasily identified in process simulation. Hot saturated vapor flow inlong pipe experience heat loss to ambient and frictional loss,condensation begin and two phase flow (i.e. mist flow, annularflow). Cold saturated or partial subcooled liquid experiencefrictional loss due to fittings, piping, etc and ambient heatingresults vaporization and two phase flow (i.e. bubble flow, wavy flow,slugging flow). Hot stream mix with cold stream may resultsequilibrium change and lead to two phase. Typical area is flarecollection system. Hydrocarbon in process vessel at pressure once
it is drained to drain collection header may flash and lead to vaporization. Generallyexample are :
Saturated vapor within plant (condensation)Cooled or subcooled liquid within plant (vaporization)Flare collectionHydrocarbon drain collection
Featured Resources:
Water & Wastewater
International
Provides practical know ledge and
insight that saves time and money for
w ater system operators,
w astew ater engineers... >>
► Liquid Flow
► Process Flow
► Oil and Gas
8/4/13 Chemical & Process Technology: Problems Caused by Two Phase Gas-Liquid Flow
webwormcpt.blogspot.com/2010/02/problems-caused-by-two-phase-gas-liquid.html 3/4
Problems Two phase gas liquid flow can cause several destructive problems. There are :
Impingement erosionSplashing erosionCavitation erosionFlashing erosionFlow induced vibrationSurge / hammerNoiseDecrease process performancePhase separation
Impingement, Splashing, Cavitation & Flashing ErosionTwo phase gas liquid flow can lead to impingement, cavitation & flashing erosion. Twophase gas liquid flowing fluid where heavy phase is accelerated with light phase andinduced high momentum and shearing stress on surface. Slugging flow in vapor-liquidsystem with large slug hammering on surface induce high momentum with mediumvelocity and high mass flux. Mist flow with droplet accelerate at vapor velocity induce highmomentum with high velocity and low mass flux. Both induce high shear stress on thesurface and increase material removal rate.
Flow Induced VibrationHigh velocity compressible fluid in pipe is moving in turbulence pattern. Turbulence flowwill induced vibration on pipe. Once the flow induced vibration frequency meeting thenatural frequency of pipe support, resonance occur can lead to severe movement of pipesupport. Present of two phase gas liquid flow can generate different level of frequency andincrease possibility of resonances.
Surge & HammerTwo phase gas liquid slugging and high velocity gas moving liquid at similar speed,severe vibration can occur when liquid slug is knocking/splashing on the pipe wall,especially at bend and elbow. Hot steam mix with cold condensate at the collectionheader results sudden steam vapor collapse. The collapse vapor results sudden lowerpressure will lead sudden replacement of surrounding condensate. Sudden movement ofcondensate can results significant movement of condensate as well as piping and pipesupport. Under designed pipe support may fail due to severe vibration.
Quick opening of valve for incompressible, multiphase and gas/vapor will results suddenchange in momentum (0 to +mv) and subsequently instantaneous peak force acting onthe piping. This phenomena is commonly occurs in control valve (CV), Blowdown valve(BDV) and pressure relief device i.e. press ure relief valve (PRV) and rupture disc (RD).The instantaneous peak force acting on the piping may potentially lead to piping failure.
NoiseAbove phenomenon such as Impingement, Splashing, Cavitation & Flashing Erosion,Flow Induced Vibration and Surge & Hammer may also generate noise which potentiallyexceeded the allowable noise limit.
Affect process performanceIn oil and gas production, condensate-produced water bulk separation occur in slugcatcher / inlet receiver follow by a Condensate separator. Some process design mayinclude a filter coalescing separator to promote water droplet coalescing (usingcoalescing element) and separation before it is sent to Condensate stabilization.Condensate at saturation point from Condensate separator feeding to Filter Coalescingseparator will experience frictional drop and potential lead to vaporization. Vapor willaccumulate in the filter coalescing separator and seriously affect Coalescing activity inFilter Coalescing Separator.
Plate heat exchanger (PHE) is used in Solvent e.g. Amine, MEG, TEG, etc regeneration torecover heat from lean solvent stream and promote energy saving. Hydrocarbon and / orvapor bubble under carry from Solvent Absorber to PHE potentially accumulate in the PHEand seriously affect the heat transfer in PHE.
Phase Separation - Mal-DistributionAir cooler used for fluid cooling is widely used in Oil & Gas and Petrochemical plant. Hotfluid is fed to a Inlet header box, distribute fluid into tubes (normally finned) where coolingtake place and cooled fluid is collected in the Outlet header box. If hot two phase gasliquid fluid feeding to the inlet header box, liquid with higher momentum tends to flowpreferential path (straight) compare to vapor with lower momentum. The lead to seriousvapor-liquid mal-distribution. Fluid (vapor dominant) feed to tube closer to inlet possiblyover cooled whilst fluid (liquid dominant) feed to tube further from inlet possibly undercooled. For large duty air cooling system, fluid may further distribute into multiple headerboxes and multiple unit air cooler, this will further create mal-distribution of fluid.
Knowing the problems caused by two phase gas liquid flow, identification of potential twophase gas liquid becoming an important activity during design phase. Process engineershall take extra care during design phase and provide necessary prevention measures tominimize / avoid occurrence of two phase flow.
Related Post
Facts about Erosion & Erosion-Corrosion Erosion & Erosion - CorrosionSeveral Criteria and Constraints for Flare Network - Process
8/4/13 Chemical & Process Technology: Problems Caused by Two Phase Gas-Liquid Flow
webwormcpt.blogspot.com/2010/02/problems-caused-by-two-phase-gas-liquid.html 4/4
© 2008-2010 Chemical & Process Technology | Design by Webworm
Assess Potential Piping Failure Due to Valve Quick Opening with Two-PhaseVapor Liquid How Fluid Characteristic affect 2 phase Relief via PSV on Liquid filled VesselExposing to External Fire
Labels: Fluid Flow, hydrualic
Process engineer jobs
Inspection EngineerShell - Miriinspection activities as per work preparationprocess aligned with the maintenance and integrityexecution... never ask you for a fee to process orconsider your...Shell
more jobs »
jobs by
posted by Webw orm, 6:59 AM
-->
Shipping Container Water Dispenser Learning
0 Comments:
Post a Comment
Let us know your opinion !!! You can use some HTML tags, such as <b>, <i>, <a>
Enter your comment...
Comment as: Google Account
Publish Preview
Subscribe to Post Comments [Atom]
Links to this post:
Create a Link
Home:<< Home
