GAS COMPRESSOR NATU NA TURA RAL L GAS GAS Co Comp mpre ress ssio ion n – NTNU NTNU 20 2010 10
Compress Compressors ors used in OIL OIL & GAS GAS Industry Industry - Emphasis on Centrifu ifugal compressor
Mahe hend nde er Re Redd ddy y Bill Billa am Dresse Dresser-R r-Rand and AS, Kongsbe Kongsberg. rg.
Gas Compressor 1 – Comp Compre ress ssor or in Na Natu tura rall gas gas prod produc ucti tion on & transport 2 – Types Types and Princi Principle ples s 3 - Ce Cent ntri rifu fuga gall Com Compres press sor Sele Select ctio ion n proc proce ess 4 – Comp Compre ress ssor or Comp Compon onen ents ts 5 – Latest Latest develo developme pments nts
What does a Compressor do
Reduce volume of gas
Increase pressure of gass
Contro Controll pressu pressure re in proce process ss
?
GAS FROM RESERVIOR TO LAND
TYPICAL OIL PLATFORM
USE IN NATURAL GAS PROCESS
ON PLATFORM
- Re Re-c -co omp mpre ress ssio ion n – oil oil produ roduc ction tion
- Expo Export rt comp compre ress ssor or (fro (from m plat platfo form rm))
- Gas Gas inje inject ctio ion n
Proces Processin sing g plant plant
- Expo Export rt (boo (boost stin ing) g)
- Pros Proses esse sesi sing ng (tak (take e ou outt wa wate ter/ r/co cond nden ensa sate te))
- coo ooliling ng circu ircuit its s
- Liqu Liquifi ifica catio tion n
Transport - Boo oos sting ting ( lo long pipe ipeline line )
COMPRESSOR IN OIL & GAS PRODUCTION
The compressors are responsible for a large part of the power demand in the oil and gas production .
Exam Exampl ple: e: I yea yearr 20 2007 07 ha have ve inst instal alle led d comp compre ress ssor or with with po powe werr requ requir irme ment nte e of over over 30 3000 0000 00KW KW..
Typi Typica call reco recomp mpre ress ssor or – 20 2000 00 kW kW ( from from 5 500 00 kW kW t0 100 10000 00 kW) kW)
Typi Typica call expo export rt comp compre ress ssor or - 25 2500 000 0 kW kW (of (ofte ten n 2 or or 3 ma mach chin ines es))
Typi Typica call inje inject ctio ion n comp compre ress ssor or - 25 2500 000 0 kW kW ( of ofte te 2 mac machi hine nes s)
Typ Typical ical ”Boo ”Boost ster er”” on land land – 25 2500 000 0 to to 400 40000 00 kW – Man any y compre compresso ssors rs at same statio station. n.
DRIVER
Comp Co mpre ress ssor or can can driv drive e wit with h bo both th cons consta tant nt spee speed d and and vari variab able le spee speed. d.
Consta Con stant nt speed speed g give ive little little flexib flexibilit ility, y, mostly mostly used used in proses prosessin sindus dustrie trien. n.
Cons Co nsta tant nt spee speed d elec electr tric ical al mo moto torr – typica picall up upto to to 500 5000 0 kW
Variab Variable le speed speed elec electric trical al mot motor or (ASDS) (ASDS) - typic typical al from from 1000 1000 t0 60000 60000 kW
Gass Gasstu turb rbin ine e – varia variabl ble e spee speed d - typi typica call from from 100 1000 0 to 450 45000 00 kW kW
Stea St eam m turb turbin ine e - varia variabl ble e spee speed d - typi typica call from from 10 1000 00 t0 50 5000 000 0 kW
Trad Tradit itio iona nalllly y gastu asturb rbin ines es are are used used on pla platfor tforms ms becau ecaus se of gas avai availa labi bililitty an and d ha has s adva advant ntag age e on we weig ight ht an and d dime dimens nsio ion n comp compar ared ed to electr electrica icall mot motor or drivers. drivers.
COMPRESSOR ON KOLLSNESS
2 TYPES AND PRINCIPLE
Compre ress ssor or Type Type • Comp • Centrifugal - principle ple
Compressor Types
Axial - large large flow, flow, low pre pressu ssure re • Axial Centrifugal - large to to medium flow, high high presssur presssuree • Centrifugal Helical Screw Screw - low flow, flow, low low pressur pressuree • Helical Reciprocating ng - medium to low flow, high pressure pressure • Reciprocati
Offshore North North Sea Sea - large flow, high high pressu pressure re •Offshore
Axial Compressor
Centrifugal Compressor
Reciprocating Compressor
Helical Screw Compressor
Basic Principles
• Centrifugal Action
• A Centrifugal Stage • Energy Conversion
Centrifugal Action
Centrifugal Action
Velocity Relationship
A
Exit Path B
Centrifugal Action Cover
Blades
Disk
High Velocity, Higher Pressure Gas Outlet
Low Velocity, Low Pressure Gas Inlet
Impellers
DIFFUSOR From Fr om imp impel elle lers rs gas gas flows flows in to dif diffu fuse serr
Diffusor
Diff Diffus user er conv conver erts ts kine kineti tic c en ener ergy gy to pres pressu sure re en ener ergy gy
How A Centrifugal Works Centrifugal Stage
Return Bend
Return Bend
Diffuser Reduces Velocity Increases Static Pressure
Return Channel
Guide Vanes
Impeller Increases Velocity Increases Static Pressure
ONE COMPRESSOR TRAIN
IMPELLER
Transfer energy -press -pressure ure og speed speed
DIFFUSOR
Con Co nvert verts s kine kineti tic c en ene ergy rgy to pressure
…
GAS COMPRESSOR 3 – Ce Cent ntri rifu fuga gall Com Compres press sor Sele Selec ction tion proc proce ess
Selection Process
Inputs required for centrifugal compressor selection
Typically Know:
Ts inlet
Ps inlet
Pd outlet
Flow (Q)
gas composition
Driver type (Gas Turbine, Steam Turbine, Motor)
Selection Process
Selection Process
Aerodynamic Selection and Optimization • Imp Impelle ellerr R Requ equire iremen ments ts (inclu (includin ding g Stre Stress) ss)
Mechanical Design • Coupling size • Bear Bearin ing g an and dS Sea eall siz sizes es
Rotordynamic Design • Cou Could ld rese reselec lectt c coup oupling ling,, bearin bearings, gs, seals seals
Polytropic Work (Head)
COURTESY OF BILL FORSTHOFFER
Basic Thermodynamic Equations
P m d 1 P s Head R T s Z avg m
m
(k 1) / k
z = compressibility R = Universal Gas Constant
Redlic Redl ich h Kw Kwon ong g eq equa uati tion on used used to calcu calcula late te compressibility(z)
(1545.3/Mw) Mw = Mole Weight k = Isentropic Exponent (Cp/Cv) Cp = Specific Heat at constant pressure Cv = Specific Heat at constant volume
Some Rotor dynamic terminology: Axial vibrations Torsional vibrations
y
z
x
Lateral vibrations
Concepts used in Rotor Dynamics: • Basic principles principles of vibratio vibrations ns • Knowledge Knowledge of of how a fluid fluid film bearing bearing works works • Influence Influence of bearings bearings on the dynamic dynamics s of the machine machine • Influence of labyrinth labyrinth and damper seals on the dynamics of the machine
Some Rotor dynamic terminology: • Rotor: Rotor: rotating element consisting of shaft, impellers/disks, shrunk-on components like sleeves, balance piston, etc. • Bearings: Bearings: Journal bearings support the rotor in the lateral direction. (Thrust bearings support the axial load of the rotor while in operation. operation .)
Some Rotor dynamic terminology (Contd.): • Natural frequency: frequency: Frequency at which the system vibrates. The frequency of vibration of a system (e.g. rotor-bearing system) with damping is called the damped natural frequency. •Ring of a bell or a tuning fork.
• Critical speed: speed: Is a natural frequency with an ‘active enough’ response that the natural frequency should be designed around. (more on this later)
• Stability: Stability: The stability stability of a system system is defined as the the “reaction” “reaction” to any external perturbation. (more on this later)
Compressor Control Recycle Valve
Recycle Increases Suction Flow
Surge!
t n e i c i f f e o C e r u s s e r P c i p o r t y l o P
SURGE LINE
COMPRESSOR DESIGN POINT
105% Speed 100% Speed
90% Speed
Flow
GAS COMPRESSOR 4 – Centrifugal Compressor components
Rotor Assembly Balance Piston Impellers Drive Coupling Mount Shaft Thrust Rotor
Bearing Journals
Impeller Spacers Seal Area
Compressor Internals • Diaphragms • Inlet/Discharge Walls • Inte Inters rsta tage ge Seal Seals s
STRAIGHT THROUGH FLOW De - -ethaniser e thaniser - -D10R5S D 10R5S
Balance piston Thrust Bearing
bearing
Gas seals
Gas seal
bearing
KOMPRESSOR ACESSORIES - COMPONENTS
Compressor
Lube oil system
Gass Gassea eall syst system em – ga gas s or oil oil
Gear and Couplings
Driver Driver - el. moto motor, r, gast gasturb urbine ine,, steam steam turbin turbine e
Foundation skid
Pros Proses esss- an anti ti-s -sur urge ge valv valve, e, scr scrub ubbe berr an and d coo coole lerr
Inst Instru rume ment ntat atio ion n an and d cont contro roll syst system em
REMOVABLE LIFTING LUG
A.V.M (anti vibration mount)
3 point support BASEPLATE with centra entrall box box beam
DRIP PAN CONNECTION
GAS COMPRESSOR 4 – Centrifugal Compressor latest develom loments
Latest Developments
Compact Compact integral integral Motor Motor driven driven compress compressor or
Latest Developments
Compact Compact integral integral Motor Motor driven driven compress compressor or - High High spe speed Ele Elect ctri rica call mot otor ors s - No ge gear arbo box x - Ma Magn gne etic tic be bear arin ings gs th that at elim elimin ina ate need ne ed fo forr oil oil lubr lubric icat atio ion n - Re Redu duce ced d fo foot otpr priint - digi digita tall cont contro rols ls inst instea ead d of an anal alog og cont contro rols ls - Emis Emissi sion on-f -fre ree e de desi sign gn
Latest Developments Inte In tegr grat ated ed Co Comp mpre ress ssio ion n Syst System em(I (ICS CS))
DATUM I Compres Compressor sor packa package ge
Latest Developments Inte In tegr grat ated ed Co Comp mpre ress ssio ion n Syst System em(I (ICS CS))
The DATUM I system provides an efficient and compact method of gas-liquid separation that uses centrifugal centrifugal forces to separate separate gas, oil and water water from the flow. The separation separation process protects the compression flow-path from potential damage by removing free liquids from the gas stream which can cause subsequent fouling during the compression process.
DATUM I can be used for ups DATUM upstrem trem,, midst midstrea ream m and down downstea steam m com compres pression sion.. Also for subsea subs ea comp compress ression. ion.
By incorpo incorpora ratin ting g Dre Dresse sserr-Ran Rand’s d’s pro propri prieta etary ry ce centr ntrifu ifuga gall sep separ arati ation on te techn chnolo ology gy ins inside ide the compres com pressor sor case case,, the the DATUM I system system effi efficien ciently tly sep separat arates es liqu liquid id from the gas stre stream. am.
Dresser-Rand’s proprietary centrifugal separation technology; a high-speed, close-coupled, gas-cooled motor; magnetic bearing rotor system; dedicated unit controls; process coolers, valves, instrumentation and interconnecting piping—all packaged in a compact module design.
