Page 120 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 3 .1 Compressor Best Practices

Best
Best Practice 3.1Practice 3.1
Use site, company and industry lessons learned to de- Lubricated screw compressor in sour gas service e never operated
termine if positive displacement or dynamic (turbo) type for more than 24 hours continuously.
compressors are required. Reciprocating compressors, used when screw compressors should
First, accurately determine all of the required operating conditions. be used, resulted in extensive maintenance costs and sour gas
Process conditions not anticipated in the selection phase account for leakage.
Rotary lobe compressors, used instead of centrifugal compressors,
80% or more of compressor reliability problems. Then use company
resulted in the need for multiple compressors when a single
guidelines for selection of the proper compressor type if available.
centrifugal compressor could have been used.
Whether company guidelines are available or not, determine the type
by site and industry lessons learned to avoid plant safety and reliability
issues. Finally, indicate the selected compressor type on the data Benchmarks
sheet with all best practices dictated by plant, company and industry
I have used this best practice since the mid-1980s in upstream, refining
lessons learned.
and chemical plants, giving the following optimum compressor
reliabilities:
Lessons Learned Centrifugal greater than 99.5%
Improperly selected compressor type has led to field Dry screw greater than 99%
safety issues, revenue and legal costs as noted by the Lubricated screw greater than 97.5%
following examples: Dry reciprocating greater than 94%

B.P. 3.1. Supporting Material Positive displacement compressors are constant volume,
variable energy (head) machines that are not affected by gas
This section gives an overview of compressor types and their characteristics.
typical applications. Dynamic compressors are variable volume, constant energy
The two basic types of compressors are positive displacement (head) machines that are significantly affected by gas
and dynamic compressors. characteristics.

Fig 3.1.1 Compressor application range chart

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