01 / The challenge
A sluggish valve was stopping the whole compressor train.
An Egyptian fertilizer plant depended on a steam turbine-driven train containing an air compressor, nitric oxide compressor and expander. The units ran continuously at full capacity, so a turbine trip interrupted nitric acid production and downstream fertilizer output.
The governor valve began responding sluggishly. Erratic movement pushed control deviation above 10% of setpoint and triggered automatic turbine trips. Each event meant an estimated six to eight hours of lost nitric acid production.
Inspection found sticky varnish on the valve stem and spool. The oil also returned an MPC varnish-potential result of 30.3 ΔE. Together, the inspection, oil result and control behaviour gave the team a clear treatment target.
02 / The approach
Remove the deposit problem while the train keeps running.
Connect the trip to the oil-system evidence
Physical inspection found sticky varnish on the governor-valve stem and spool. Membrane patch colorimetry, or MPC, measured varnish potential at 30.3 ΔE. The deposit evidence and the sluggish response pointed to an oil-related cause.
Treat the circulating oil
NATCOM recommended DECON™. Two drums were added to the lube-oil reservoir while the compressor train remained in service. The treatment needed no shutdown, flush, oil change or additional hardware in this system.
Check the oil result and the control response
The existing filtration captured material mobilised into the oil. Before-and-after MPC tests tracked the change, while the operating team followed governor response, control deviation and further trips.
03 / The documented outcome
Lower varnish potential and a more responsive governor.
MPC fell from 30.3 to 9.4 ΔE, a 69% reduction. Governor-valve response improved and control deviation stayed below the 10% trip threshold after treatment.
The plant reported no further varnish-related turbine trips. The case does not state the length of that follow-up period. Treatment took place with the train operating and the existing oil retained.
Fluitec estimates more than US$280,000 in net benefit for the first treatment cycle, based on three modelled avoided shutdowns at roughly US$100,000 each.
- MPC varnish potential
- 30.3 → 9.4 ΔE
- MPC reduction
- 69%
- Control deviation
- Remained below the 10% trip threshold
- Varnish-related trips
- None reported after treatment
04 / Applying the findings
Follow the valve response as well as the oil.
For another sticking governor valve, bring the trip history, inspection findings and oil trend together. Our guide to governor-valve sticking and varnish explains how to investigate the symptom and distinguish the possible causes.
A treatment assessment should review the lubricant, reservoir volume, equipment requirements and existing filtration before selecting a dose. Oil analysis then provides a starting point and a follow-up plan that can be compared with the machine response.
The practical acceptance test is whether the governor responds consistently and the oil condition stays on track. Record both over an agreed period so that the team can judge continued performance after the initial improvement.