The
New Fifth Edition of API 618 for Reciprocating Compressors –
Which Pulsation and Vibration Control Philosophy Should You
Use?
J. D. Tison and K. E. Atkins, 30th Turbomachinery Symposium,
The Turbomachinery Laboratory, Texas A&M University, Houston,
TX, September 2001.
The proposed Fifth Edition of API 618 (“Reciprocating Compressors
for Petroleum, Chemical, and Gas Industry Services”) incorporates
significant changes in the section concerning pulsation and vibration
control. There are still to be three “design approaches,”
but the requirements to perform certain analyses that were presented
as optional in the Fourth Edition will now be dependent on pressure
pulsation and force levels determined from the acoustical simulation.
The confusion concerning then piping forced mechanical response
calculations should be performed, which originated in the Fourth
Edition, has been eliminated; forced response calculations are not
required to satisfy API 618 Fifth Edition when pulsation levels
are controlled properly.
A separate
article on pulsation and vibration control is being developed
by the API 618 sub-task force on pulsation and vibration control
as an appendix (annex) to API 618. This text will be a stand alone
“RP” (Recommended Practices) document in the API system,
which would then be referenced by API 618 as well as other API
standards (e.g., API 674 for Positive Displacement Pumps) for
which pulsation and vibration control are an issue. This document,
to be issued in 2002, will discuss the different design philosophies
inherent to the new edition of the standard.
The purpose
of this tutorial is to provide the user with a working knowledge
of good engineering practices for pulsation and vibration control
of reciprocating machinery in relatively high mole weight gases
(e.g., natural gas), as well as an in depth understanding of the
proposed changes in API 618 and the differing design philosophies.
Several case histories are used to illustrate why robust pulsation
control is important for reciprocating compressor piping systems.
The authors
are members of the API 618 sub-task force on pulsation and vibration
control and each has over 20 years of experience in this field.
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