Compressors

Valdel Engineers and Constructors, Ltd.

WELCOME TO THE WONDERFUL WORLD OF PIPING

COMPRESSORS BY:

SAMI UR REHMAN PIPING DEPARTMENT

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INTRODUCTION OF COMPRESSOR 

Compressors are machines which are used to increase the pressure of a gas by mechanically reducing its volume with in its casing.  Closely related to the pumps.  Pressure and temperature will increase.  Gases are compressible fluid.  Process, Chemical reactions that takes place at elevated pressure.  Transportation or transmission of gases through pipelines.

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CLASSIFICATION OF COMPRESSORS Compressors can be further classified on its working principle  Positive displacement compressors.  Dynamic compressors.

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Reciprocating Compressors 

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Reciprocating compressors are machine in which The compressing element is a piston following a reciprocating (linear) motion in a cylinder. Temperature is increase due to increase kinetic energy of the molecules. Generally used for small to medium volume and compress gas to extremely high pressure. Piston

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Two Stage Horizontal Reciprocating Compressor

MOTOR

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Lines Size 1 Stage 24”to 18” 2 Stage 18”to 12” 3 Stage 12”to 10”

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Three stage Reciprocating Compressor

Compressor Driver Generally Electrical motors are used for reciprocating compressors these are of two types Synchronous and Induction motor. Synchronous

motor is exactly same as that of rotating magnetic field they are used for higher power and lower RPM. Efficiency of synchronous motor is 94-97 and is better than induction motor.

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Electric Motor

Auxiliary Equipment

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It is supplied by compressor vendor as a skid mounted package with equipments, its internal piping arrangements, controls and instruments. Generally skid consists of these two systems. Lubrication system Cooling system

Lubrication System

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Lubrication is lifeline of any rotating machinery. the lube oil system Contains reservoir, a pair of circulation pump, shell tube coolers and a duplex filter arrangement . The main function of the lubrication are Minimize friction and to avoid contact between moving parts. Remove heat induced by friction Protect metal from corrosion.

Lube Oil Console

Lube oil console maintenance 9

Auxiliary Equipment

Lube Oil Skid 10

Use of Lubrication Generally, two oil pumps are provided for lubrication, one driven by crankshaft is known as main oil pump (MOP) and other driven by separate elective motor is called auxiliary oil pump (AOP).

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Cooling System Heat is generated due to compression of the gas friction in the cylinder . The need to provide cooling can be performed with  Air  Water (open and close water cooling) Its difficult to control these limits in open system the PH value range of 6.5 to 8. Hardness should be less than 200 ppm. Suspended solids less than 100 ppm. Its very easy to add additives in close circulation Water- glycol solution which has low freezing point and high boiling point with respect to water use in close circulation. 12

Accessories Suction Separator Because compressors requires dry gas free of foreign particles, the inlet gas is passed through suction drum. Its function is to remove oil and condensates from the gas, the principles of operation are Gravity, Impingement, Centrifugal force and Filtration

Pulsation Dampener or Volume Bottle   

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Volume bottles accumulate sufficient volume(5-20 times of cylinder) of gas to render uniform flow of gas. Pulsation dampers are devices with the internal system capable of cutting off certain frequencies. The Pulsation dampers must be installed as close to the cylinder as possible to avoid the possibilities of acoustic resonance between cylinder and device.

Suction Separator

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Pulsation Dampener or Volume Bottle

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Location and Maintenance When locating compressors, consideration must be given to  Operability  Safety  Maintenance

RECIPROCATING COMPRESSORS Reciprocating compressors must be mounted close to grade. Because of the extreme vibration in the piping system. Compressor foundation elevation depends on these steps

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Setting Elevations of Reciprocating Compressors

Nozzle 3.Minimum Distance Required to enter the header

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Well Ventilated

Proper Access To Valves

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Reciprocating Compressors Arrangement

At Least Two Stairways

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Reciprocating Compressors Arrangement Well Ventilated To Prevent Gas Build Up From Leaks

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Open Installation And Enclosed Structure

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Planning For Cylinder Removal

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Reciprocating Compressors Piping

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Reciprocating Compressor Piping        

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Allowable nozzle load Eccentric Reducer with the flat side on the bottom of the pipe to prevent the accumulation of any liquids Isolation valve with spectacle blind shall be provided in the inlet and outlet piping Temporary strainers must be used in inlet. Branch connecting shall be minimized or located at near to the point where the header is anchored. Piping shall be routed as close to grade or to heavy concrete foundation as possible. Positive displacement machinery shall be equipped with a PRV. Pressure measurement connection complete with isolation valves shall be provided on the inlet and outlet piping.

Reciprocating Compressors Typical Piping

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Compressors line branch

Reciprocating Compressor With all Components

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Reciprocating Compressor Support    

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Pipe support must be given special consideration due to the pulsation. Rigid anchors, to provide lateral stiffness needed to restrain dynamic force Compressor piping should never be supported from shelter steel work or operating floor. And must be provided with independent foundation to avoid transmission of vibrations.

Reciprocating Compressor Support

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Centrifugal Compressor    

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Dynamic type compressor are machine in which air or gas is compressed by the dynamic action of rotating vanes or impeller. Centrifugal compressors are used to handle large volume of gas to moderating high pressure. Gas enters the machines at the axis of high speed impeller and discharges radially into a peripheral chamber at high pressure. Centrifugal compressors may have horizontally split or vertically split casing .

Horizontal Split Case Compressor

Vertical Split Case Compressor

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Centrifugal Compressor

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Centrifugal Compressor With Lube Oil Console

Centrifugal Compressor

Lube Oil Console 32

COMPRESSOR DRIVES 

Electrical motor  Steam turbine  Gas turbine

Steam Turbine  

Back Pressure turbines are driven by high pressure steam and do not require surface condenser. Condensing turbines are usually driven by low pressure steam.

Gas Turbine Usually employed in remote area, where gas is available for fuel. 33

Elevation for Centrifugal Compressors

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Auxiliary Equipment For Centrifugal Compressors Air

filters Waste heat system Lube oil seal oil console Surface condensers Condensate pumps

Maintenance & Location of Centrifugal Compressors 

The oil console is located closely at the turbine end to facilitate a free draining lube oil return to the reservoir .  Control panel is located On the operating floor at the driver end  The size of the operating floor must be established by allowing clearance of 6 ft all around machine.  An access road is required for mobile handling equipment.

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Grade Mounted Centrifugal Compressor Open-Sided Structure

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Grade Mounted or Elevated Centrifugal Compressor Open-Sided Structure

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Grade Mounted Compressor Wall Shelter

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Elevated Centrifugal Compressor No Shelter

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Vertical Condensate Pump

Removes the condensate from the hot well in the surface condenser

Inlet Air Filter Gas turbines require large amounts of clean filtered air for operation 42

Seal Oil Console

Reduce gas or vapor to a liquid by removing heat 43

Surface Condenser

Waste Heat System

Hot exhaust gas from gas turbines may be used to generate steam or heating the oil and may be used as a heating medium

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ELEVATION OF COMPRESSORS 

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The operating floor elevation is next established by making the required headroom allowance beneath horizontal pipe run under the floor while allowing the lube oil return header to slope down To its connecting point on the reservoir. The major factor in setting the elevation of the minimum height that satisfy NPSH requirements of the condensate extraction pumps. The straight run requirements of the suction line its could be varies between 3D to 8D.

Surface Condenser Elevation

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Elevated Compressor

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CENTRIFUGAL COMPRESSORS PIPING & SUPPORT Nozzle allowable loads. Straight run requirements 3D to 8D Suction and discharge piping on bottom

entry installations should

Preferably be run close to grade. Do not support compressor piping from the compressor foundation structure . Strainer must be installed. All Valves must be accessible ,preferable from grade. Additional flanges for maintenance. Alignment is more easily achieves if adequate field fit up welds are allowed in spools

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Centrifugal Compressor Inlet & Outlet Nozzles

Lines Size Inlet 84” outlet 42”

Outlet line 49

Inlet Line

Straight run requirements

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Strainer Must Be Installed.

Additional Flanges For Maintenance

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Valves Must Be Accessible

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QUESTION ??

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