Typical troubles in lube oil and dry gas seal systems

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A dry gas seal.

Typical problems encountered in lube oil and dry gas seal systems are given below:

Lube oil system

Reservoir: heater damage, insufficient heating for cold starts or poor thermostat control

High water content in reservoir

Collapsed filter cartridges during low ambient temperature start-ups

Steam turbine main pump driver – poor reliability (frequent trips, H20 in oil)

Unit trip or system instability during auxiliary oil pump start

Low lube oil pressure trip during auxiliary oil pump start or low oil pressure trip when aux pump is shut off with main running

High oil filter delta P


Poor oil temperature control

Transfer valve damage / idle side leakage

Bearing damage during Plant Black incident

Seal oil system

Low oil flash point or loss of viscosity index

Seal oil system instability or trips as a result of reference pressure changes

Sleeve seal overhead tank response time

Excessive contaminated seal oil leakage rates

Contaminated seal oil drainer failure to drain

Oil ingestion into the process

Control oil system

System instability following control valve movement

Unit trip during system upset

Inability to maintain accumulator pre-charge

Auxiliary oil pump start during ramp up

System instability during auxiliary oil pump start

Dry gas seal system

Primary seal failure due to reverse pressurization

Process contamination during settleout

Increase in settleout pressure as unit awaits restart

Barrier seal excessive wear

Primary / secondary seal excessive wear during coastdown

Barrier seal oil ingestion

Excessive filter change outs during commissioning

Primary seal increase in leakage over time 

Secondary seal failure due to liquid ingestion

Primary / secondary seal failure due to extended turning gear or crank time

Secondary seal fugitive emissions

High secondary seal vent flow.