IHI TRE60 Compressor — First Major Overhaul After 44,000 Hours

A complete first major overhaul of an IHI TRE60 three-stage centrifugal air compressor at a steel mill in northeast China — impeller inspection, cooler descaling, rust repair and full seal & bearing replacement, carried out by Turbomax engineers.

IHI TRE60 impeller and diffuser after opening the gearbox

Machine background

This IHI TRE60 three-stage centrifugal air compressor was delivered in 2007 and has been running at a steel mill ever since. At the time of the overhaul the machine had accumulated around 44,000 running hours — and this was its first major overhaul. That such a long first overhaul interval was possible says a lot about the robustness of the IHI TRE design, but after so many hours a full inspection and consumables renewal was overdue.

Model	IHI TRE60 (three-stage centrifugal air compressor)
Capacity	100 m³/min
Discharge pressure	0.9 MPa
Motor	Siemens 850 kW, 2,984 rpm
Running time at overhaul	≈ 44,000 hours (first major overhaul)

Condition found during overhaul

After opening the air end, the overall condition was better than expected for 44,000 hours — but the cooling water side told a different story:

Impellers (1st/2nd/3rd stage) — only light dust; dye penetrant inspection showed no cracks or damage
Coolers — inlet tubes of all three stages heavily blocked with white scale deposits; copper tubes severely plugged
Cooler end covers & cooling chambers — heavy rust on the water side (2nd/3rd stage cold side)
3rd-stage guide vanes — cavitation marks at the inlet
Gearbox — carbon deposits on high-speed and low-speed shafts (cleaned)

Photos from the job

1. Impellers — dye penetrant inspection

① As found — light dust only

IHI TRE60 1st-stage impeller as found — light dust — 1st-stage impeller — light dust only

IHI TRE60 2nd-stage impeller as found — light dust — 2nd-stage impeller — light dust only

IHI TRE60 3rd-stage impeller as found — light dust — 3rd-stage impeller — light dust only

② During dye penetrant test

IHI TRE60 1st-stage impeller dye penetrant test in progress — 1st-stage impeller — penetrant applied

IHI TRE60 2nd-stage impeller dye penetrant test in progress — 2nd-stage impeller — penetrant applied

IHI TRE60 3rd-stage impeller dye penetrant test in progress — 3rd-stage impeller — penetrant applied

③ PT result — no defects found

IHI TRE60 1st-stage impeller PT result — no cracks — 1st-stage impeller — PT shows no cracks

IHI TRE60 2nd-stage impeller PT result — no defects — 2nd-stage impeller — PT shows no defects

IHI TRE60 3rd-stage impeller PT result — no damage — 3rd-stage impeller — PT shows no damage

2. Cooler copper tubes — descaling

① As found — blocked by white scale

IHI TRE60 1st-stage cooler tubes blocked by white scale — 1st-stage cooler tubes — blocked by white scale

IHI TRE60 2nd-stage cooler tubes with heavy white pollution — 2nd-stage cooler tubes — heavy white pollution

IHI TRE60 cooler tube bundle close-up of white scale — Cooler tube bundle — close-up of white scale

② After cleaning — every tube cleared

IHI TRE60 tube sheet after cleaning — all tube entrances open — Tube sheet after cleaning — all entrances open

IHI TRE60 cooler tubes after descaling — fully cleared — Cooler tubes after descaling — fully cleared

3. Cooler end covers — rust removal by grinding

① As found — heavy rust

IHI TRE60 1st-stage cooler end cover with heavy rust — 1st-stage end cover — heavy rust

IHI TRE60 2nd-stage cooler end cover with heavy rust — 2nd-stage end cover — heavy rust

IHI TRE60 3rd-stage cooler end cover with heavy rust — 3rd-stage end cover — heavy rust

② After grinding

IHI TRE60 cooler end cover after grinding — bright surface — End cover after grinding — bright surface

IHI TRE60 cooler end cover after grinding — rust removed — End cover after grinding — rust removed

IHI TRE60 cooler end cover after grinding — clean metal — End cover after grinding — clean metal surface

4. Cooling chambers — cleaning

① As found — rust on the cold side (2nd / 3rd stage)

IHI TRE60 1st-stage cooling chamber — relatively clean — 1st-stage cooling chamber — relatively clean

IHI TRE60 2nd-stage cooling chamber — heavy rust on cold side — 2nd-stage chamber — heavy rust on cold side

IHI TRE60 3rd-stage cooling chamber — heavy rust on cold side — 3rd-stage chamber — heavy rust on cold side

② After cleaning

IHI TRE60 cooling chamber after cleaning — rust removed — Cooling chamber after cleaning — rust removed

5. Guide vanes — cavitation repair (3rd stage)

① As found — light dust, cavitation at 3rd-stage inlet

IHI TRE60 1st-stage guide vane — light dust — 1st-stage guide vane — light dust

IHI TRE60 2nd-stage guide vane — light dust — 2nd-stage guide vane — light dust

IHI TRE60 3rd-stage guide vane — cavitation at inlet — 3rd-stage guide vane — cavitation at inlet

② After grinding & polishing

IHI TRE60 1st-stage guide vane after grinding — 1st-stage guide vane — after grinding

IHI TRE60 2nd-stage guide vane after grinding — 2nd-stage guide vane — after grinding

IHI TRE60 3rd-stage guide vane after grinding — cavitation repaired — 3rd-stage guide vane — cavitation repaired

6. Air filter — replacement

① Removed old filter elements

IHI TRE60 removed dirty air filter elements — Removed dirty air filter elements

② New elements installed

IHI TRE60 new air filter elements installed — New air filter elements installed

7. Bull gear bearing & shaft — condition check

IHI TRE60 bull gear thrust bearing pads in good condition — Thrust bearing pads — good condition

IHI TRE60 bull gear shaft journal in good condition — Bull gear shaft — journal in good condition

IHI TRE60 bearing assembly after inspection — Bearing assembly after inspection

Scope of work — parts replaced

1st / 2nd / 3rd stage air seals
1st / 2nd / 3rd stage oil seals
High-speed and low-speed bearings
Air filter elements (new)
Oil filter element
Oil mist separator
Lubricating oil (renewed)
After-cooler end cover gasket
Main oil pump coupling element
Main oil pump O-rings

In addition: complete cleaning of all cooler copper tubes (every tube cleared one by one), grinding of rusted end covers and cooling chambers, repair grinding of the cavitated 3rd-stage guide vanes, gearbox carbon cleaning, vibration probe gap voltage re-adjustment to standard, and cold alignment of motor and compressor.

Root cause & our recommendation

The white scale inside the cooler tubes came from the plant's cooling-tower water. We recommended treating the water at the upstream cooling tower to stop scale from entering the cooling circuit — otherwise the coolers will slowly plug again and cause high temperature trips. After the overhaul the compressor was restarted and all operating parameters returned to normal.

Planning an overhaul for your IHI TRE compressor?

Turbomax supplies alternative spare parts and overhaul service kits for IHI TRE and other IHI centrifugal compressor series, and supports overhaul projects worldwide. Our founder has 10 years of IHI-Sullair field service experience.

Email us for a quotation WhatsApp +86 13814834140

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