Carboblast cleaning of Gas Turbine

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fraz
Core Member
Posts: 32
Joined: 29 Mar 2010, 18:07
Area of interest: Manufacturing Engineering

Carboblast cleaning of Gas Turbine

Post by fraz »

We are planning to perform the Carboblast cleaning on one of our Gas turbines. Can anybody share the details of Carboblast cleaning. What is the procedure? What is used for cleaning? How much time should be taken for cleaning etc? Its a GE frame 5 gas turbine.
ben
Posts: 165
Joined: 24 Aug 2010, 03:11
Area of interest: Mechanical Engineering

Re: Carboblast cleaning of Gas Turbine

Post by ben »

Carbo-blasting is a cleaning method for gas turbines with natural media like walnut shells, rice husks, spent catalyst, apricot pits etc. This cleaning method uses the solid cleaning media and is quite effective in de-fouling the turbine and compressor blades. Media is commercially available which is normally a mixture of walnut shells with other agents. It should be carefully selected considering the hardness of media and the metals along with their protective coatings.

The procedure of carbo-blasting is as follows:
1. Turbine is prepared for cleaning by removing internal instrumentation equipment, or fittings that may become plugged by impingement of the media.
2. All open fittings, tubing, arid air bleed ports must be effectively closed with a cap or tape.
3. For injection of media, small fittings are installed in the inlet injection nozzle. An impingement cone is usually placed to provide more uniform distribution of the media.
4. Approximately 200-250 lbs. of media should be uniformly injected over a period of 30-40 minutes while the turbine is being operated at lower speeds.
5. The turbine should be run for an additional 5 minutes at idle, and shut down.
6. All temporary caps and enclosures should then be removed and the turbine operated again for 5 minutes to blow out the media residues that may have
accumulated in the fittings.
7. Reinstall all instrumentation equipment and fittings that were removed prior to the cleaning operation.

There are other methods also for cleaning the gas turbines but the best would be the manufacturer's recommended one. One must see what has been specified by the manufacturer and should follow the same.

Special care and safety precautions must be taken if going for carbo-blasting.
fraz
Core Member
Posts: 32
Joined: 29 Mar 2010, 18:07
Area of interest: Manufacturing Engineering

Re: Carboblast cleaning of Gas Turbine

Post by fraz »

What are the possibilities of carboblasting material deposition over the compressor blades, in case their is an excessive lube oil leakage from the turbine bearing # 1 resulting in the formation of possible sludge on the compressor blades?
ben
Posts: 165
Joined: 24 Aug 2010, 03:11
Area of interest: Mechanical Engineering

Re: Carboblast cleaning of Gas Turbine

Post by ben »

It depends on the grade of media you are using for carbo-blasting and the amount of leakage.
Very fine grade may result in formation of sludge.
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