Prabhakar,
I would like to respond to one part of your query. Can oils last forever! German engineers strongly feel good engine oils can last forever. After my interactions with MAN, Wartsila service engineers I would like to share, with this forum the framework to support the “infinity theory.”
The two main factors essential to make oils, last forever are, large volume and sufficient residence time. The other factors may be standard parameters like:
a) Top-up 2 to 4%
b) Sulphur in Fuels below 4%
c) Monitoring of KV 40 & 100, Flash, TBN and ensuring a variance of not more than 20 %. Correction, sweetening, top-up as and when required to correct variance.
d) Moisture/Water below 200 ppm.
e) Needless to say the grade of oil has to be an OE approved grade.
1. Sump: At least 25000 Lt ( 20 kl), less than that, is NOT COMMERCIALLY VIABLE.
2. Sump sequence & arrangement: 10000 Lt Dirty oil tank (DOL) where used oil from engine passes through a filter (Standard Alfa Laval type Centrifuge available in MAN and Wartsila installations) and resides. This helps in Heat and Mass Transfer and maintains Material and Energy Balances (MEB) and also allows time for "very fine" dirt/contamination to precipitate.
The oil then moves to a 10000 lt clean oil tank (COT) from where it can be pumped into the engine.
Hussam Adeni