SOLAR GAS BOOST COMPRESSOR OUTLINE Pengenalan Centrifugal Gas Compressor Prinsip Kerja Gas Compressor Compressor Component dan Fungsinya Staging Selection Performance Evaluation Compressor Cleaning / Stripdown Restage
Pengenalan Centrifugal Gas Compressor Centrifugal Gas Compressor adalah salah satu Compressor yang termudah yang ada untuk menaikan tekanan dari gas dengan aliran kontinyu. Solar Compressor Family - C-160 - C-284 - C-306 - C-338 - C-505
Prinsip Kerja Gas Boost Compressor Prinsip Kerja Centrifugal Gas Compressor adalah mengubah energy kecepatan dari gas menjadi energy tekanan dan Fungsinya untuk menaikan tekanan dari gas untuk keperluan tertentu.
Gas Flow Through Impeller
Compressor Stage Component
Compressor Component dan Fungsinya
Casing & End Cap. Rotor Stator Bearing Seal
Housing & End Cap Sebagai manifold / penampungan gas inlet (suction cavity) dan gas outlet (discharge cavity) yang designnya pressurenya disesuaikan dengan Kondisi operasinya / operating point.
Housing & End Cap Gas Compressor C-304
Stator Merupakan bagian yang diam / stationary yang terdiri dari : - Guide Vane - Diffuser.
Guide Vane berfungsi sebagai pengarah dari aliran untuk menuju ke impeller. Diffuser berfungsi untuk mengubah energy mekanik / gerak dalam hal ini kinetik energy menjadi energy tekanan / pressure.
Rotor Merupakan susunan dari beberapa buah impeller yang stagingnya telah di
sesuaikan dengan kebutuhan operasinya dan berfungsi untuk mempercepat aliran gas sebelum memasuki diffuser daipada stator
Rotor
Pin
Center Stud
Bearing Berfungsi untuk meredam getaran yang ditimbulkan oleh compressor dan type yang digunakan kebanyakan adalah Hydrodynamic journal bearing yang lazim kita sebut sebagai tilt pad bearing Alasan kenapa memilih Tilt pad bearing - Effekivitas untuk meredam getaran sangat tinggi - Meniadakan oil whirl / oil whip - Life timenya relative lama
Tilting Pad Bearing
Thrust Bearing • Be Berf rfun ungs gsii unt untuk uk me mena naha han n gay gayaa axi axial al • Ada dua macam type – Tilt Tilt pa pad d th thru rust st be bear arin ing g – No Non n Tilt Tilt pa pad d thru thrust st bea beari ring ng
• Ada Ada yan yang g dil dilen engk gkap apii den denga gan n sen senso sor, r, un untu tuk k memonitor thrust bearing temperature
Tilt Pad Thrust Bearing Pad
Temperature sensor
Seals Seal System terdiri : - Labyrinth : Bentuknya sekat-sekat yang tiap ujungnya berbertuk runcing / tajam dan berada dikedua sisi impeller atau stub shaft dan berfungsi untuk meminimize / mengurangi kebocoran gas diantara tiap-tiap stage didalam compressor . - Buffer Gas / Seal Gas Berfungsi untuk menjaga agar seal oil / lubrikasi tidak masuk kedalam compressor / process - Seal Oil Berfungsi untuk menjaga agar process gas tidak masuk kedalam system pelumasan / lubrikasi.
Labyrinth Seal (1) Stationary Housing Kondisi Seal sebelum beroperasi Rotating Shaft
Gas Flow
Soft Babbit Replaceable liner Kondisi Seal sesudah beroperasi
Labyrinth Seal (2)
Labyrinth Seal
Seal Oil dan Buffer Gas Sistem Fungsi : “Sebagai sealing antara sistem oil dan sistem gas” Seal Oil : Mencega Mencegah h masuknya gas ke sistem oil Buffer Gas : Mencegah masuknya seal oil ke
compressor casing
Seal Oil & Seal Buffer Gas
Seal Oil & Seal Buffer Gas (cont,d)
Buffer Gas DP
Seal Oil & Seal Buffer Gas (cont,d) Buffer Gas Seal P = 55 psig Lubricating Oil
Balance Piston Seal (Discharge)
P = P-suct + 20 psi
P = P-suct + 15 psi
Seal Oil
Buffer Gas
P-suct / P-disch Gas dalam Compressor Discharge Suction
Seal Oil dan Buffer Gas Drain
Komponen Seal oil System • Auxiliary Seal Oil Pump – Start saat tekanan prelube > 6 psig – Berhenti saat loading speed (90% NGP) – Saat engine Shutdown, Start pada saat 90% , berhenti Pcasing < 4 psig
NGP <
Komponen Seal oil System (1) Main Seal Oil Pump Mengambil alih Auxiliary Seal Oil Pump pada NGP > 90% 2000 rpm pada 100% NGP
Flow Regulator Menjaga aliran seal oil konstan pada setiap tekanan
Komponen Seal oil System (2) Differential Pressure Regulator Seal Oil DP Regulator Menjaga tekanan seal oil 20 psid di atas tekanan suction
Buffer Gas DP Regulator Menjaga tekanan buffer gas 15 psid di atas tekanan suction
Tekanan acuan : Tekanan Suction atau Drain Cavity ( Seal Oil dan Buffer Gas Out )
Komponen Seal oil System (3) Seal Oil DP Regulator Diaphragm
Seal Oil IN
Seal Oil Return
Buffer Gas
Maximum Seal Oil Leakage
Komponen Seal oil System (3) Seal Oil Separator / Trap Memisahkan gas dari seal oil agar tidak masuk ke Lube Oil Tank Meyakinkan seal oil tidak tertarik ke pipeline melalui booster compressor Seal Oil kembali ke tank dibantu oleh tekanan gas di atasnya
High Pressure Oil Trap
Type Seal Oil Trap Seal Oil & Gas Mixed
Gas out Floater
Oil return port Spring
Oil out
Sistem Buffer Gas Internal
Gas dari Balance Piston labyrinth seal (discharge) diregulasi tekananya, diinjeksikan sebagian ke suction bearing capsule Eksternal
Gas dari discharge elbow diregulasi tekanannya, diinjeksikan ke suction dan discharge bearing capsule
Sistem Buffer Gas-Internal Gas-Internal
To Suction pipe
BG Reg.
To Suction Brg. Capsule
Sistem Buffer Gas-External Gas-External
External Buffer Gas sources
BG Reg
Buffer Gas DP Operating Range Model No.
Buffer Gas DP (psig) Minimum
Nominal
Maximum
C-16
5
15
50
C-16H
5
15
50
C-160
5
15
50
C-28
5
15
50
C-30
5
15
50
Dry Seal System In this system, separation of lube oil and process gas is accomplished by a series of seals, installed between the inboard journal bearing and the impeller.
Buffer Gas •
Bufferr gas Buffe gas is inje injecte cted d betwe between en the the prim primary ary sea seall and and the the labyri labyrinth nth sea seall on the rot rotor or hub, hub, at pres pressur suree above suction pressure.
•
The dif differ ferent ential ial pres pressur suree and pro propo porti rtiona onall flow flow path path sizes sizes caus causes es most most of of the bu buffe fferr gas gas flows flows acro across ss labyrinth seal and back to suction chamber of the compressor.
•
The rem remain aining ing sma small ll amou amount nt of of buff buffer er gas flo flows ws acro across ss prim primary ary sea seall and and is ven vented ted fro from m the the seal seal assembly through a fixed orifice and flame arrester to a safe area.
•
A secon secondar dary y seal seal is is insta installe lled d adjace adjacent nt to to the the prima primary ry seal seal,, actin acting g as a backu backup p in the eve event nt of of failu failure re of of the primary seal.
•
Diff Di ffer eren entt pres pressu sure re reg regul ulat ator or mai maint ntai ain n a dif diffe fere rent ntia iall of approximately 20 psi above suction pressure. pressure.
Buffer Air •
The buf buffer fer air sea seall is a spl splitit-rin ring g circu circumfe mferen rential tial seal seal,, adjace adjacent nt to to the the inbo inboard ard jou journa rnall beari bearing ng of of the the compressor rotor.
•
Air or Nitr Nitrog ogen en is is suppl supplied ied to the the sea seall at a regu regulate lated d pres pressur sure. e. Sm Small all por portio tion n flow flowss acros acrosss the the inner inner seal seal and out the secondary seal vent. The balance of the buffer air flows across outer portion seal into lube oil drain (mixed with LO draining from journal bearing)
•
Differ Diff eren entt pres pressu sure re reg regul ulat ator or mai maint ntai ain n a dif diffe fere rent ntia iall of approximately 10 psi between seal inlet and the secondary seal vent port
Dry Seal System Component Description •
Buffer Air DP Regulator –
Norm No rmal ally ly ope open n dia diaph phra ragm gm an and d pop poppe pett type type
–
Second Sec ondary ary ven ventt press pressure ure and spr spring ing act on on the the OPEN OPEN side side of the the valv valvee diaph diaphrag ragm m
–
Seall inlet Sea inlet pre pressu ssure re act actss on the CLO CLOSE SE sid sidee of the val valve ve diap diaphra hragm gm
–
The oppo opposin sing g forces forces main maintai tain n equili equilibri brium um at at the pre pre-ad -adjus justed ted set set point point of of the valv valvee Normally 10 psid
•
Buffer Air DP Transmitter –
Conn Co nnec ecte ted d betw betwee een n seal seal inl inlet et and and sec secon onda dary ry sea seall vent vent lin linee
–
Sends Sen ds an elect electric rical al signal signal prop proport ortion ional al to the the pressu pressure re acros acrosss the inbo inboard ard buff buffer er air air seal to the control system
•
–
If DP falls below 7 psi, and ALARM will be activated
–
If DP falls below 4 psi, a Fast stop SHUTDOWN will be initiated.
Buffer Gas DP regulator –
Norm No rmal ally ly ope open, n, Dia Diaph phra ragm gm an and d pop poppe pett type type
–
Suctio Suc tion n press pressure ure and spr spring ing pre pressu ssure re acting acting on the the OPEN OPEN sid sidee of the the diap diaphra hragm gm
–
Buff Bu ffer er Gas Gas inl inlet et on on the the CLO CLOSE SE si side de of of the the dia diaph phra ragm gm
–
Thee valv Th valvee is adj adjus uste ted d to bal balan ance ce the the dia diaph phra ragm gm at at nomi nomina nall pressure of 20 psid
Dry Seal System •
Buffer Gas DP Transmitter – – –
•
Buffer Gas Filter DP Transmitter – –
•
Monitorr DP fil Monito filter ters, s, provi provides des a propo proporti rtiona onall signa signall to con contro troll syste system m indicating filter condition If DP DP exce exceeds eds 40 psi psid, d, ALA ALARM RM sig signa nall will will be be init initia iate ted d
Buffer Gas Flow-Limiting Orifice – –
•
Connected Connec ted betw between een suct suction ion (refe (referen rence) ce) line line and and the the buffe bufferr gas sea seall inlet inlet line line If DP DP fall fallss belo below w 7 psi, psi, wit with h engi engine ne spe speed ed at at 90 % or hig highe herr If DP DP fall fallss belo below w 4 psid psid,, with with eng engin inee spee speed d at 90 90 % or hi high gher er
0.295 0.29 5 size size ori orifi fice ce,, inst instal alle led d in th thee buffe bufferr gas gas IN lin linee Limits Lim its the flow flow of gas gas as the the labyr labyrint inth h seal seal wears wears and and its its clearan clearances ces incr increase easess
Buffer Gas Flow-Monitoring Orifice –
0.25 size 0.25 size orific orifice, e, instal installed led in in the prim primary ary seal seal vent vent line line,, to measu measure re seal seal leakag leakagee flow flow In the vent line
–
with the orifice, is adjusted adjusted to open at 30 psid, provides an A relief valve, connected in parallel with escape gas in the event of a serious failure of the primary seal. Reducing the possibility of ovepressurizing the buffer air seal and contaminating the lube oil system with gas.
Dry Seal System •
Primary Seal Vent Alarm and Shutdown Transducer –
Conn Co nnec ecte ted d to to the the pr prim imar ary y sea seall ven ventt lin linee
–
Provid Pro videe signal signal to the the contro controll system system repre represen sentin ting g the absol absolute ute pressu pressure re at the the vent vent port port
–
If the pressure at the vent line 12 psig, ALARM signal will be activated
–
If the pressure at the vent line 20 psig, SHUTDOWN signal will be activated
NOTE The back pressure at the primary seal vent v ent must not exceed 5 psig
SECONDARY SEAL VENT
2nd seal Hi Flow Alarm switch
PRIMARY SEAL VENT
R A A
A
S/D
S/D S/D BALANCE PISTON
A
BUFFER GAS
S/D
LO IN LO IN R
AIR / N2
Balance Piston & Seal • Bala Balanc ncee pis pisto ton n ada adala lah h bag bagia ian n dar darii rot rotor or yang digunakan untuk mengurangi gaya axial • Bala Balanc ncee Pis Pisto ton n ada ada pa pada da si sisi si di disc scha harg rge, e, setelah internal staging yang terakhir
Balance Piston & Seal (1)
Balance Piston & Seal (2)
Balance Piston
Balance Piston & Seal (3)
PERFORMANCE OF CENTRIFUGAL COMPRESSOR
Performance Evaluation Evaluasi Penting karena : Mengetahui existing Performance (Optimal atau Tidak) Mengetahui Kondisi Kompressor (Fouling, excessive seal wear dll) Mengambil keputusan perlu atau tidak compressor cleaning atau compressor Re-Staging
Adapun Performance Evaluation meliputi : -
Compressor Theory Physical Properties of Gas Head, Flow and Efficiency Compressor Performance Curve / Map Compressor Horse Power Performance Analysis and Their Problem A rise
Compressor Theory • Persamaan Euleur • Persamaan Bernouli • Hu Huku kumm-hu huku kum m The herm rmod odiina nami mika ka – Pro Proces cesss Adia Adiabat batik ik / Isen Isentro tropik pik – Pr Proc oces esss Pol Polyt ytro ropi picc
Energi Gas • Terdiri dari : Head (tekanan) dan Flow • Horse Power = Head X Flow • Head adalah besaran enersi yang diberikan kepada gas untuk setiap satu besaran massa.
Gas Physical Properties • Specific Gravity • Ratio of Specific Heat • Compressibility factor
Specific Gravity (s.g) • Adalah : Perbandinga Perbandingan n molecular weight dari gas mixture terhadap Molecular weight udara. • Molecular weight udara = 28.964 Mol weight gas mixture
• SG = --------------------------------------------------------------28.964
Compressibility factor (Z) • Adalah factor koreksi volume dari perhitungan gas ideal menjadi gas actual. • Harga Z selalu < 1
Compressibility factor (Z)
Sample of Gas Analysis
Perhitungan SG
Compression Head 53.35 x Z av x k x T1 Head
(k-1)/k
= ----------------------------------[ (P2/P1) SG x (k-1)
Head = Ft. Lbs force / Lbs mass. Z ave =Compressibility factor k
= Ratio of specific heat
T1
= Temperature gas suction (Deg R)
P1
= Pressure gas suction (psia)
P2
= Pressure gas discharge (psia)
SG
= Specific Gravity gas
-
1]
Horse Power Required 1.6417 x 0.001 x Head x Flow MMSCFD x SG HP = ---------------------------------------------------------------Efficiency
HP
= Horse power yang dibutuhkan oleh compressor yang tersedia pada shaft compressor.
Isentropic Efficiency (k-1)/k T1 [ (P (P2/ 2/P P1)
-1]
Eff = ------------------------------------------------------------------T2 - T1
Compressor Curve / Map Ada tiga macam Curve – Di Dime mens nsio iona nall Cur Curve ve – Se Semi mi-D -Dim imen ensi sion onal al Cu Curv rvee – He Head ad vs vs Capac Capacit ity y (Flo (Flow) w) Cur Curve ve Rule :
The Head versus Capacity curve is the only curve necessary
Dimensional Curve Use for Bid evaluation Pressure versus Standard Flow Determines operating range Based on Constant Suction or Discharge Pressure No Longer of value after purchase decision
Can determine specific operating Condition Power & Speed
Shape of curve very demendent on base conditions Suction Temperature Suction Pressure Discharge Pressure Gas Composition
Semi-Dimensional Semi-Dimens ional Curve Use for Bid evaluation Pressure Ratio versus Standard Flow divided by pressure Determines operating range Based on Constant Suction or Discharge Pressure No Longer of value after purchase decision
Can determine specific operating Condition Power & Speed
Shape of curve very demendent on base conditions Suction Temperature Suction Pressure Discharge Pressure Gas Composition
Head versus Capacity Curve Only affected slightly by changes in base conditions – Suction and Discharge Temperature – Discharge Pressure – Gas Composition
Used to determine the condition of an operating compressor – Compare actual efficiency to nominal (curve) efficiency – Compare actual speed to nominal (curve) speed
Performance Diagnostics Method 1. Actual versus Nominal Data •
•
Actual Speed
Measured
Efficiency
Calculated (from measured data)
Nominal Speed
From Fro m Head Head – Cap Capaci acity ty curve curve
Efficiency
From Fro m Head Head – Cap Capaci acity ty curve curve
Performance Diagnostics Method 2.
Creates 9 possibilities EFFICIENCY
SPEED
COMMENTS
OK
OK
OK
LOW
Check speed, P1, P2, and SG measurement
OK
HIGH
Possible compressor damage
LOW
OK
Possible compressor damage, Check T1, 2
LOW
LOW
Data probably suspect, Check P1,2 and SG
LOW
HIGH
Possible comp. Damage. Check Flow measurement
HIGH
OK
Comp. Probably OK. Data possibly suspect. Check T1,2 measurement
HIGH
LOW
Comp. Probably OK. Data definitely suspect. Check T1,2 measurement
HIGH
HIGH
Comp. Probably OK. Data definitely suspect. Check T1,2 measurement
Compressor probably OK
Yard Valve Sequence
Yard Valve Sequence
Yard Valve Sequence
