All about compressor design and operation

Compressor

1. Compressors

2. Standardsand Codes
API STD 617
Centrifugal Compressors for Petroleum, Chemical, and Gas Industry Services
API STD 619
Rotary Compressors for Petroleum, Petrochemical, and Gas Industry Services
API STD 618
Reciprocating Compressors for Petroleum, Chemical, and Gas Industry Services
API STD 681
Liquid Ring Vacuum Compressors for Petroleum, Chemical

3. Compressors Classification
Kinetic
A –Centrifugal
B –Axial
Positive Displacement
C -Reciprocating
D -Rotary
*Screw
* Lobe
*Sliding Vane
*Gear
* Others

4. Main Types Of Compressors
HIGH LOWV. HIGH
NO NOYES
LOW HIGH V. HIGH
YES NO NO
Pressure P
Flow Rate Q
S .R .V
Efficiency
Maint. cost
Pulsation
Surging
Positive D.P.Centrifugal Axial Flow
V. HIGH
LOW LOW
LOW MEDIUM V. HIGH
NO YES YES

5. Compressor Selection
Reciprocating
Single stage
Centrifugal
Single stage
Rotary-Screw

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6
DifferentTypes of Compressors
DisadvantagesAdvantagesType
Centrifugal
Axial
-
Positive
displacement
-Wide operating range
-Low maintenance
-High reliability
-Unstable at low flow
-Moderate efficiency
-High efficiency
-High speed capability
-Higher flow for a given
size
-Low pressure ratio per stage
-Narrow flow range
-Fragile and expensive blading
-Pressure ratio
capability not affected
by gas properties
-Good efficiencies at low
specific speed
-Limited capacity
-High weight to capacity ratio
-Higher maintenance requirements
Introduces vibrations into the
system
-Bigger foundation requirements

7. 7
Centrifugal
Axial
Efficiency
Specific speed
N s
Centrifugal
Positive
displacement
Axial
50 %
60 %
70 %
80 %
90 %
Pressure
% Rated Capacity
100 %
Positive
Displacement

9. IMPELLERS IN ROW
MULTI-STAGE
COMP.

10. OPPOSITE IMPELLERS
MULTI-STAGE COMP.

11. IMPELLERS IN ROW
MULTI-STAGE
PUMP

12. DIFFUSER
IMPELLER TIP BALANCE PISTON

13. SPLIT TYPE
COMPRESSORS
1-Horizontally Split
High Flow Medium pressure

14. 2-Vertically Split (Double Barrel)
high pressure and medium Flow

15. Axial Flow Compressors
* API 617
* Very High Flow rate
* Low pressure
* Very High efficiency

16. Discharge
Stationary
Aerodynamics
Inlet
Cover
Thrust
Bearing
Rotor
Journal
Bearing
Dry Gas Seal
Casing
Dry Gas Seal
Shear Ring
Journal Bearing
Balance Piston
*API 617 * Medium pressure
* High Flow rate * High efficiency

17. Reciprocating Compressor
* API 618 * Low Flow rate
* High pressure * Moderate efficiency

18. Rotary-Screw Compressor
* API 619
* High Flow rate
* High pressure
* Moderate efficiency

19. ** Compressor Selection
Application
Operating parameter
footprint/weight
Availability
Reliability
maintenance
drivers

20. 20
Centrifugal Compressor

21. Radial
Bearings
Radial
Bearings
Thrust
Bearing
Centrifugal Compressors
Impellers
Mechanical
Seal
Mech.
Seal

22. ** Compressors components
Rotor Shaft Thrust collarsImpellers Spacers
Diffusers
Casing
Mechanical Seals
Couplings HSC LSC
Gear Box
Driver
Anti-Surge System
Lube Oil System
Labyrinths
Centrifugal Compressor

23. 23
General aspects
1-A Complete spare balanced rotor to be ideally
stored in ware house
2-Compressor will be equipped with a complete
surge control system.
3-It is advisable to use dry gas mechanical seal
system instead of wet mechanical seal one.

24. COOLER
SCRUBBER
1
St
Stage
ANTI-SURGE
VALVE
SCRUBBER
** Centrifugal Compressor Operation

25. COOLER
SCRUBBER
1
St
Stage
ANTI-SURGE
VALVE
COOLER
SCRUBBER
ANTI-SURGE
VALVE
SCRUBBER
2
Nd
Stage
** Centrifugal Compressor Operation

26. COOLER
SCRUBBER
1
St
Stage
ANTI-SURGE
VALVE
COOLER
SCRUBBER
ANTI-SURGE
VALVE
COOLER
SCRUBBER
ANTI-SURGE
VALVE
SCRUBBER
2
Nd
Stage
3
Rd
Stage
** Centrifugal Compressor Operation

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3 Stages
Geared Centrifugal
Compressor
Cooler
Cooler

28. 28
Surge
Phenomenon

29. 29
AXIAL FLOW
COMPRESSORS
CENTRIFGAL
COMPRESSORS
AND
HAPPENS
ONLY TO :
But Does not Happen to
Reciprocating
Compressors

30. It is the flow back of gases from the outlet of the
Last stageof the compressor towards the suction and
return again to discharge
SURGE PHENOMEN
IN OUT

31. •FLOW-RATE IS NOT ENOUGH
•GAS PROPERTY
•FLATENESS OF P.C. AT LOW Q
•COMPRESSOR PERFORMANCE
Why
SURGE PHENOMEN

32. •FLOW-RATE
IS NOT ENOUGH
•GAS PROPERTY
This will happen at
starting and shutdown,
also at abnormal conditions.
Gas is compressible but liquid is not.

33. •FLATENESS OF P.C. AT LOW Q
•COMPRESSOR PERFORMANCE
Centrifugal and Axial compressors are pumping
gas continuously but reciprocating is not.
Gas pressure has the same energy at
horizontal portions of the performance curve

34. INLET FLOW RATE Q IS ENOUGH
IN OUT
NO SURGE
IF

35. OUT
5to 20cycles per second
IN
IF INLET FLOW RATEQ
IS NOT ENOUGH
COMPRESSOR
IS SURGING

36. 36
SURGE PHENOMENON
H
p
A
B
QM³/ hr
10000 6000

37. Compressor Turbine
MOTION
HYDRAULIC
ENERGY
HYDRAULIC
ENERGY
MOTION

38. SURGE WILL DAMAGE THE COMPRESSOR
THRUST BEARINGS
EFFECT OF SURGE ON
CENTRIFGAL COMPRESSOR
ROTOR
THRUST
BEARINGS

39. SURGE WILL DAMAGE THE
COMPRESSOR THRUST BEARINGS
THRUST
BEARINGS
COMPRESSOR

40. 40
SURGE CYCLE
QM³/ hr-Q
Hp
B1
10000 6000
5to 20cycles per second

41. 1-BY PASSWITH ANTI -SURGE VALVE
ANTI-SURGE METHODS
2 –BLOW OFFVALVE
THIS METHODS IS COMMONLY
USED FOR GAS COMPRESSORS
THIS METHODS IS COMONLY
USED FOR AIR COMPRESSORS

42. 42
1-BY PASSWITH ANTI -SURGE VALVE
P,TFT
UIC
FY
COMRESSOR
COOLER
ANTI-SURGE
VALVE WILL
OPEN
ANTI-SURGE METHODS
IN CASE OF
COMPRESSOR
SURGING

43. 43
6000 M
3
COMRESSOR
10000 M
3
4000 M
3 4000 M
3
6000 M
3
P,TFT
UIC
FY
COOLER
ANTI-SURGE
VALVE
FY =TRANSDUCER
UIC=ANTI-SURGE INTEGRATED CONTROLER
1-BY PASSWITH ANTI -SURGE VALVE

44. 44
BY PASSWITH ANTI -SURGE VALVE
GRAPHICALLY
A
H
p
C
Q M³/ hr
B
SURGE CONTROL LINE
RECYCLE TRIP LINE
SURGELIMIT LINE

45. 45
2 –BLOW OFF VALVE
FY =TRANSDUCER
UIC=ANTI-SURGE INTEGRATED CONTROLLER
BLOW
OFF
VALVE
Air
3
6000 M
P,TF
T
UIC
FY
AIR
COMRESSOR
10000 M
3

46. 46
2 –BLOW OFF VALVE
A
B
GRAPHICALLY
Q M³/hr
Hp
B1

47. 47
IN CASE OF GAS TURBINE
AIR COMPRESSOR SURGE
BLEED VALVE WILL OPEN
COMPRESSOR
TURBINE
BLEED VALVE

48. 48
Positive Displacement
Compressors

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Reciprocating Compressors

50. ReciprocatingCompressors Construction

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Reciprocating Compressors properties
•Lower Power Density
•Low Speed (300–1800 rpm)
•Generally used in low volumetric rate applications
(< 500 acfm[850 m
3
/h] )
•Higher maintenance
•Unaffected by changes in gas properties (MW, T)
•Most common driver –gas engine, electric motor
•Pulsating flow/vibration

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Crosshead
Stuffing
Box
Packing
Discharge
Valves
Suction
Valves
PistonDistance
Piece
Con-rodCrank
Piston
Rod
Wiper
Rings
Reciprocating Compressors construction

53. Multi stage reciprocating compressor
ACCUMILLATOR
PULSATION
DAMPENER
GAS
GAS
COOLER
SCRUBBER
SCRUBBER
ACCUMILLATOR
PULSATION
DAMPENER
1St2nd
53

54. 54
COOLER
SCRUBBER
1
St
Stag
e
COOLER
SCRUBBER
COOLER
SCRUBBER
SCRUBBER
2
Nd
Stage
3
Rd
Stage
Multi stage reciprocating compressor
Compressors intermediate pressures

55. 29 August 2023 55
ACCUMILLATOR
PULSATION
DAMPENER
Design applications
of reciprocating
compressors
GAS
COOLER
SCRUBBER
SCRUBBER
ACCUMILLATOR
PULSATION
DAMPENER
1St2nd

56. 29 August 202356

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57
Reciprocating Compressors Flow Regulation
1-VARIABLE CLEARANCE
3-VARIABLE SPEED
4-BYPASS
2-SUCTION VALVE UNLOADERS
•Manual Operated Clearance
•Pneumatic Operated Clearance
5-Shut down the Compressor Periodically
(Start-Stop Operation)

58. 29 August 2023 58
Manual Operated Clearance
There is a clearance existed in the cylinder head.
A piston rod complete with an adjustable nut is
connected to piston with packing to seal the
clearance volume in font of the compressor piston.
The more the clearance volume in font of the comp.
piston, The less the compressor flow rate.
No effect of the clearance volume in font of the
piston on the compressor discharge pressure.
1-VARIABLE CLEARANCE

59. Clearance Volume Effect
Clearance
Head
Nut
Clearance
Volume

60. Manual Operated Clearance
CYLINDER HEAD
60
Clearance Head
Controlling Nut
VARIABLE
CLEARANCE
VOLUME
Clearance Volume Effect

61. 29 August 202361
VARIABLE
CLEARANCE
VOLUME

62. 29 August 2023 62
Point gsuction valves open
C = Clearance volume
C
v
b
a
c
g
Pd
Psc1
M
EFFECT OF
CLEARANCE
VOLUME
At
Point asuction valves closed
Point bdischarge valves open
Point cdischarge valves closed

63. Compression ratio
Pressure ratio (ABSOLUTE)
Pd
P s
=
Volumetric efficiency
=
Va g
Vcylinder aM
a g
=
=
Vcylinder
VbM
C
v
b a
c
g
Pd
Ps c1M
b
bM
a M
=

64. 29 August 2023 64
C
v
Pd
Psc1
M
b
a
c
Volumetric efficiency=
Va g
Vcylinder
aM
a g
=
g

65. 29 August 2023 65C
v
Pd
Ps
M
b
a
c
g
Volumetric efficiency=
Va g
Vcylinder
aM
a g
=

66. 29 August 2023 66
v
Pd
Ps
M
C
a
bc
g
Volumetric efficiency=
Va g
Vcylinder
aM
a g
=

67. 29 August 2023 67
If CIncreasedsuction valves will open at ( g )
C
v
a
c
g
Pd
Ps
b
M
EVDECREASES
QDECREASES
Volumetric efficiency=
Va g
Vcylinder
aM
a g
=

68. 29 August 2023 68
If C Decreasedsuction valves will open at
(g)
QINCREASES
Volumetric efficiency=
Va g
Vcylinder
aM
a g
=
EVINCREASES
C
v
a
c
g
Pd
Ps
b
M

69. 29 August 2023 69
Compression ratio
Pressure ratio (ABSOLUTE)
Pd
P s
=
Volumetric efficiency
=
Va g
Vcylinder aM
a g
=
=
Vcylinder
VbM
C
v
b a
c
g
Pd
Ps c1M
b
bM
a M
=

70. 29 August 2023 70
•SUCTION VALVE UNLOADERS
There are an unloaders existed on suction valves of
the compressor and pneumatically operated
If the unloaders energized, the suction valves will
be opened.
If there are 4 suction valves and the unloaders are
energized for :
1-One suction valve (Capacity will be ¾ max. Q)
2-Two suction valve (Capacity will be ½ max. Q)
3-Three suction valve (Capacity will be ¼ max. Q)
4-Four suction valve (Capacity will be = 0 Q)

71. 29 August 2023 71
SUCTION
VALVE
UNLOADER

72. 29 August 2023 72
Air Compressor Dryer
https://www.youtube.com/watch?v=6tVw9VYQDIg

73. Wet Air
to AtmosphereACTIVATED REGENRATED
Dry Air to instrument Receiver
AIR COMPRESSORS DRYER
TWO WAY
VALVE
TWO WAY
VALVE
AIR FROM
COMPRESSOR

74. AIR COMPRESSORS DRYER
REGENRATED
ACTIVATED
Wet Air
to Atmosphere
Dry Air to instrument Receiver
AIR FROM
COMPRESSOR

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Reciprocating Compressor Operations
https://www.youtube.com/watch?v=ooBJMI0H7PQ

76. Discussion

77. 77
Rotary
Compressors

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Rotary
Compressor
Relief
Valve

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Screw compressor
•Dry Screw Compressor
•Oil Flooded Screw Compressor

80. 29 August 2023 80
Rotary Screw Compressors

81. 29 August 2023 81
Rotary-Screw Compressor

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Rotor profile of the four ------lobe male and the six lobe female

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Oil –flooding system for a rotary screw air compressor.
Oil injected to
compressor
compressor
Air Outlet
Dry Air
Hot Oil
Cold Oil

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Multiple-screw double-end arrangement

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ROTARY
COMPRESSORS
External Gear
THE FLUID IS TRAPPED BETWEEN ROTOR AND
CASING

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THREE LOBE
COMPRESSORS

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TWO LOBE
COMPRESSOR

88. 29 August 2023 88
TWO LOBE
COMPRESSOR

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Gap,
no contact
Dry helical screw compressors.
(driven by external timing gears).

90. 29 August 2023 90
TIMING GEAR FUNCTION
2-Keeps No Contact
Between Rotors
1-Transmit Motion
To Other Rotor
3-Prevent Wear
Between Rotors

91. 29 August 2023 91
contact
Injected oil
Rotary helical screw oil injected compressor

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92
Suction
Discharge
Rotary Vane Compressor

93. 29 August 2023 93
Rotary Vane Gas Compressors

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THREE LOBE
COMPRESSORS

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TWO LOBE
COMPRESSOR

96. 29 August 2023 96
External
Gear
THE FLUID IS TRAPPED BETWEEN ROTOR AND CASING

97. 29 August 2023 97
Internal Gear

98. 29 August 2023 98
Driving
rotor
Crest