Depending on a specific intended use of compressor equipment, gas composition, performance characteristics, and capacity, compressor stations of different types can be utilized. Compressor stations have a wide application in petroleum and gas recovery industry and perform the following functions:
- gas transport;
- gas pumping into formations and underground storage facilities;
- associated petroleum gas utilization after crude oil separation stages;
- oil/gas fields power supply via fuel gas compression and feed;
- application for technological processes at oil refineries;
- gas processing, fractioning, and hydrocarbon gas liquefaction;
- operation of refrigeration units within the configuration of gas treatment plants and for cryogenic processes.
By the principle of operation, compressors can be divided into positive displacement and dynamic compressors. Positive displacement compressors comprise reciprocating/piston, rotary screw, rotary vane, and diaphragm compressors; dynamic compressors are centrifugal compressors.
Reciprocating compressors
Reciprocating compressors resolve a wide spectrum of issues: from the compression of process gases at chemical and petrochemical production facilities, natural and associated petroleum gas compression (for feeding the gas from the wellhead into the gas pipeline for the reinjection into the reservoir) to the production of high-pressure air for pipeline testing.
Most often, such compressor units are used in production processes that require a medium and high pressure at a medium and low efficiency.
Depending on a process, this compressor type can be categorized as: cylinder lubricated and cylinder non-lubricated.
For the main drive of this compressor type, electric motors and gas-piston engines can be used.
Rotary screw compressors
By design, screw compressors are referred to rotary compressors. The compression of medium is performed by two meshed helical screws. A rotary screw compressor consists of a housing (cylinder) and male and female rotors.
With respect to a technological process, this compressor type can be both oil-free and oil-injected.
Rotary screw compressors can be used for feeding gas to gas-turbine plants, natural and associated petroleum gases transfer, gases refrigeration and compression.
This type of compressor is driven either by an electric motor or by a gas-piston engine.
Rotary vane compressors
The main components of the flow-through part of a rotary vane compressor are an off-center rotor and radial, movable vanes.
The main subassembly of a rotary vane compressor is a cylindrical stator with an eccentrically mounted in its housing rotor, supported at its ends. The rotor has grooves for movable vanes that slide against the stator walls.
Rotary vane compressors are intended for quite a narrow spectrum of issues and are applied, as a rule, for the compression of low separation stages associated petroleum gas due to certain discharge pressure limitations and capacity.
Most often, such compressors are used in production processes that require a low pressure at a limited capacity.
Electric motors are mostly used as the main drives of this compressor type.
Diaphragm compressors
In diaphragm compressors, a metal or polymer back and forth moving membrane is employed as a functioning element. The drive shaft rotating motion is converted by a crankshaft into the reciprocating motion of a rod, rigidly bound with the flexible membrane.
Diaphragm compressors are best suited for the compression of all gases without gas leakage and contamination.
Inherently, a diaphragm compressor is a variant of the classic reciprocating compressor. Diaphragm compressors are intended to resolve a pretty narrow spectrum of objectives and are used, as a rule, for the compression of practically all process gases, but they have a limited capacity.
Most often, such compressors are used in production processes that require a very high pressure at a limited capacity.
Electric motors are mostly used as the main drives of this compressor type.
Centrifugal compressors
Centrifugal compressors are a type of dynamic compressors. They have a number of features that make this equipment indispensable for a variety of industries.
The centrifugal compressors key advantage is a complete absence of lubricating oil in the working cavity and, correspondingly, in the compressed medium, thus ensuring high quality of the final product.
With a comparatively low weight and compact size, the compressors of this type have a very high capacity and are capable of compressing large volumes of gas. Their technical maintenance is easy, and they can work continuously for up to five years.
Centrifugal compressors are successfully employed in the gas, chemical, petrochemical, glass industries, metallurgy, mechanical engineering, power engineering, and other industries where the absolutely oil-free gas and, also, medium to high compressed media flow rates at a low, middle, and high pressure are required.
Electric motors and gas-turbine engines are used as the main drives of centrifugal compressors.