Process compressor shaft end seals can be divided into three main categories:
- Clearance seals (e.g. labyrinth seals, restrictive-ring seals)
- Oil seals (e.g. liquid-film seals, mechanical (contact) seals)
- Self-acting dry gas seals (e.g. dry running seal)
On-line process compressor washing
In principle, process compressors equipped with oil seals or self-acting dry gas seals can be cleaned on-line. However, this shall be studied and confirmed on a case-by-case basis, since each process compressor application is different and designed according to site specific conditions. Minor modifications of the shaft end seals and/or seal support system may be required (in case of self-acting dry gas seals).
In case of process compressors equipped with self-acting dry gas seals, the primary seal gas shall be supplied at the right temperature, i.e. at least 20 °C above the dew point. The dew point margin must be maintained throughout the seal system and not just at the supply connections.
On-line cleaning of process compressors equipped with clearance seals should be avoided. There is a high risk that foulants being washed away by the cleaning solution will accumulate in these seals thereby affecting their proper functioning.
Off-line process compressor washing
In principle, process compressors equipped with clearance seals, oil seals or self-acting dry gas seals can be cleaned off-line. However, this shall be studied and confirmed on a case-by-case basis, since each process compressor application is different and designed according to site specific conditions.