Page 14 - Compression Machinery for Oil and Gas

Chapter 1

Oil and Gas Compressor Basics

Kevin Hoopes*, Timothy C. Allison* and Rainer Kurz †
* †
Southwest Research Institute, San Antonio, TX, United States, Solar Turbines, Inc., San Diego,
CA, United States

Overview of Compressor Types

Gas compressors operate by adding work to a gas to increase the pressure of that
gas as it flows through them. They are used in many different applications from
everyday items such as vacuum cleaners, automobiles, and air conditioners to
large industrial scale compressors for chemical processing, jet engine propul-
sion, and natural gas processing and transmission. They are separated into
two distinct groups: positive displacement compressors and dynamic
compressors.

Positive Displacement Compressors
Positive displacement compressors operate by decreasing the volume of a gas in
a trapped volume. Because they operate on a trapped volume of fluid, positive
displacement machines operate on distinct portions of the fluid at a time; as such
their mechanical behavior, operating speed, etc., is very different than dynamic
machines. Examples of compressors of this type include reciprocating compres-
sors, screw compressors, and scroll compressors.

Dynamic Compressors

Dynamic compressors operate by continuously increasing the momentum of a
gas as it flows through them and do not rely on a trapped volume. Examples of
compressors of this type include centrifugal (also called radial) compressors,
axial compressors, and mixed flow compressors. The major distinctions
between these categories come from how the fluid enters and exits the machine.
In a centrifugal machine, the fluid flows into the machine parallel to the axis of
rotation and out of the machine radially or perpendicular to the axis of rotation.
In axial machines, the gas enters and exits the machine parallel to the axis of
rotation. As their name suggests, mixed flow machines are a mixture between
purely centrifugal and purely axial machines.

Compression Machinery for Oil and Gas. https://doi.org/10.1016/B978-0-12-814683-5.00001-8
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