Standards Development

Scope

This document focuses on recommended condition monitoring techniques for detecting and diagnosing developing machine faults associated with the most common potential failure modes for reciprocating compressors.

This document is intended to improve the reliability of implementing an effective condition monitoring approach for the reciprocating compressors.

This document is also intended to help create a mutual understanding of the criteria for successful reciprocating compressor condition monitoring and to foster cooperation between the various application stakeholders.

This document is intended for end-users, contractors, consultants, service providers, machine and parts manufacturers and instrument suppliers.

The condition monitoring and diagnostics strategy and techniques described in this document technically apply to reciprocating compressors with many different machine configurations (e.g. vertical/horizontal/L-type/V-type/W-type cylinder orientation, number of stages, speed range, cylinder lubrication, capacity control, cylinder cooling) and used in many different industrial applications.

From a cost benefits perspective, however, this document is most relevant for critical, possibly single-line units vs. standby units and/or medium to large sized units that are over 1 000 kW.

The vast majority of these types of reciprocating compressors are used primarily in hydrocarbon and chemical processing industries and natural gas transport and storage facilities. As these machines are used extensively in the upstream, midstream and downstream oil & gas industries, the focus will be on these applications but this by no means excludes critical applications in other industries.

Some of the applicable reciprocating compressors covered by this document include:

a) Slow (under 600 r/min) and moderate speed (600-1 000 r/min) units manufactured and procured according to ISO 13707/API 618 (whichever is most up-to-date);

b) High-speed and pre-packaged units (over 1 000 r/min) on a skid that are manufactured and procured according to ISO 13631/API 11P (whichever is most up-to-date);

c) Hyper compressors used for secondary ethylene compression in low density polyethylene (LDPE) production;

d) Lubricated and non-lubricated machines;

e) Water-cooled and gas-cooled machines;

f) Horizontal, vertical V-type, L-type and W-type machines;

g) Horizontal, vertical machines with piston rings and those with labyrinth seal pistons (vertical machines only);

h) Single-acting and double acting compression;

i) With tandem cylinder configuration;

j) Single and multi-stage compression;

k) With and without capacity control;

l) Ring, poppet, reed and plate valve types;

m) Compressors mounted on flexible and rigid structures;

n) Compressors driven by electric motors, gas and diesel engines, turbines (with or without a gearbox), all with a flexible or rigid coupling;

o) Integral gas-engine-driven compressors (engine portion out of scope);

p) Offshore applications, such as platforms, FPSOs, FLNGs, FPU and fixed installations.

NOTE  

FPSO - Floating Production Storage and Offloading

FLNG - Floating Liquified Natural Gas

Reciprocating compressors not covered are:

1) Diaphragm compressors;

2) Compressors with single-acting trunk-type (automotive-type) pistons that are connected directly with the crankshaft by a connecting rod (there is no piston rod or crosshead);

3) Plant or instrument-air compressors with a discharge pressure of 9 barg (125 psig) or less.

This document focuses on the compressor itself (cylinders, distance pieces, crosshead, frame and all internal parts) and not on the prime mover or the external systems such as piping, scrubbers, pulsation vessels, and pulsation control devices. Only brief mention is made for monitoring the foundation/skid/pedestal.

The scope does not include monitoring the auxiliary systems such as for lubrication, cylinder cooling, intercoolers and gas purging, but process parameters from these systems are often monitored.

The scope does not cover installation analyses of systems either, such as pulsation and mechanical response analysis of the piping, thermal analysis of piping.

Emissions regulations have recently become more stringent, therefore monitoring leak gas to the atmosphere is briefly mentioned in this document.

This document covers online (permanently installed) and portable instrument condition monitoring and diagnostic techniques for operating reciprocating compressors.

Machine testing, which is only done during shutdown, although very important, is not part of the scope of this document. Nor is one-time acceptance and performance testing within the scope.

The condition monitoring techniques presented in this document cover a wide range of continuous and interval-based monitoring techniques under generalized conditions for a wide range of applications.

The actual monitoring approach required, however, can be different from one application to another.