After the upgrade job on C4001 compressor in 2014 and its problem-free running for 2 years, Stavrolen desided to upgrade 4 more compressors - C2001, C3301, C4101, and K-101. In 2017 these compressors were upgraded - dry gas seals systems were installed instead of the original wet type mechanical seals.
The compressors were Thomassen and Borsig centrifugal machines, with 1-3 number of bodies/casings. The compressed gases were propelene, pyrogas, recicling gas, and reaction gas.
The original wet mecahical seals suffered from oil leaking and getting into the process (gas) and then to heat exchangers, which led to oil loss and to formation of deposits in heat exchangers. Also, the wet mechanical seals needed an overhaul every year.
The tasks for each compressor upgrade were:
-design and install a dry gas sealing system;
-modify the lubricating system;
-radically increase compressor MTBR;
-stop oil from getting into the process gas, to increase gas quality and decrease oil losses;
-increase lube oil life;
-decrease gas losses.
During the upgrade jobs, body covers and rotors were modified. The lube systems were modified because oil is not needed in dry gas seals so some of the oil system components were removed.
In the end, 4 compressors (7 bodies) were upgraded at the same time(!). Prepation and the upgrade itself took 9 months. Thanks to high quality work of Stavrolen Maintenance and engineers from TREM-Kazan, the start up of upgraded compressors went in one go. The three double end machines started operation in October, and the 4th, console type, started operation in December of 2017.
As of today, the compressors have been running for a year, without any issues.
Stavrolen, LLC is a major petrochemical plant of Lukoil situated in the town of Buddenovsk in the South of Russia.