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Hi I am working in a power plant using GE gas turbine (frame 6B with Mark-V operating system). During off-line water wash of the compressor we always use the portable water. Now our plant is going for combined cycle operation. So we have a WTU that makes DI water. Is this DI water is good for compressor wash? Our STG is S/D condition for many days. But due to keep the WTU in operation, we have to produce some DI water and drain it everyday. So we want to use this water for compressor washing. Is this ok or not?

If you have a heavy-duty gas turbine packaged and provided by GE and supplied with off-line water washing, your instruction manual will include a publication which lists the water quality required for water washing, as well as the required detergent characteristics. This should all be available in the Off-Line Water Washing tab of Vol. I of the GE Instruction books.

If you don't have this publication, you can contact your GE Energy Services representative and he/she should be able to provide an electronic copy of the document very quickly.

markvguy

Hi,

In reference to your query, please note that demineralised water is almost always specified by the OEMS. This helps avoid contamination by trace elements such as NA and K. if you need more information on online and offline compressor washing please write to me on altaf. kadri @ woodgroup. com

I have some inquiries.

I work in a technology center. We are working in an offline washing system for axial compressor (Ruston TB 5000 Turbine). We have designed a mobile equipment to supply DI water and Biodegradable detergent. We defined some points to drain in the turbine and designed the tubing and flexible hoses arrangement to connect them in a common header. I would like to know if you have any experience in complete washing system and if you could give me any important advice.

Thanks.
martm03 @ yahoo. com

About the question raised by the originator, it is always advisable to use demineralised water to do the compressor washing (offline and online) to ensure the thorough cleaning and life span of the compressor blades. During offline wash also, detergent such as ardox are used in certain volume to be mixed with the DI water before injection to the blades. However please note that should the water based detergent such as ardox is used, ensure that the soaking time is not to long and there is enough rinsing to prevent detergent clogging to the blades and thus decreasing the load after the wash.

I wish to get some suggestions and advices regarding the offline washing. Is it advisable to to utilize the inspection holes available on GTs to shoot in water jet (maybe with hot water) for some extra cleaning. Has anybody tried this method and is there any possible problems that could arise from doing this?

Another question is during the online washing, the recommended washing water temperature is about 16-20C but will it be better if the wash water temperature is set to 80-90C? For info I'm operating GE Frame 9E GTs. Thx for any input.

Where did you get the 16-20 degree number? We perform washes frequently here and always use hot (66-93 degrees C) water. The GE procedure states that hot water (66-93 degrees C) may clean deposits better than cooler water when used without a detergent. According to the procedure, you need wheelspace temperatures below 66 degrees. You also need to ensure that the wheelspace temperatures are within 49 degrees of the water temperature to prevent thermal shock.

well actually the washing skid has 2 water temperature selector namely cold and hot. from the MS9000 Service Manual: Turbine Accessories and Generator V1B, i found that the temperature setting for cold is about 16-20C and 80C for hot. it also stated that for online washing, the selector should b set to cold and reduced load. However, at the moment, we set the selector to hot even for online washing as well as we believe that it would yield better cleaning. about the wheel space temp, the temp difference between the water and wheel space should be less 49C.

Those holes on compressor are meant for inspection only, hence leave them alone. What if some foreign particle is present in the water hose? If this enters the GT compressor, you'll have to dismantle your compressor after your next start-up!

For GE GTs Onlinewash is done at baseload, you should not play with your inlet temp. by spraying hot water. Hence Online wash is best done with the wash water at ambient temp.

My performance Tests on GE-9E machines reveal following waterwash frequency as optimum.

Online water wash - Twice a week (say Monday & then Thursday)

Offline waterwash - Once in 4 months. (Thrice a year)