Turbine - Compressor Water Wash and Cleaning Systems / Frequently Asked Questions

 

  1. Potential lead time to have a unit delivered once it is ordered?
  2. Is there machining on the cone for the new cone nozzles or are the original locations used?
  3. Do you have an option for online soap washes?
  4. Is the water heated for online washes?
  5. Why do I need high pressure?
  6. Do I need detergent for your system?
  7. Can I feed more than one compressor from the same skid?
  8. Why is droplet size so important?
  9. What type of nozzle do you use and why?
  10. How often should a compressor be washed?
  11. How long is the cycle for washing?
  12. Where does the water go when washing? Does it drain?
  13. How far back in the compressor will it clean?
  14. Will we see erosion in the compressor section?
  15. Can I use the system for fogging or power augmentation?
  16. Why should a power plant operator be interested in compressor water wash?
  17. Why is the GTE compressor wash system more effective than other systems?
  18. How long does it take to recover the cost of investment for a GTE water wash system?
  19. How long does it take to install?
  20. Can the water wash system be integrated into plant controls?
  21. What are typical cycles for online and offline washing?
  22. Are the existing wash nozzle locations in the turbine inlet used when installing GTE’s water wash system?
  23. Can you guarantee performance recovery?

Potential lead time to have a unit delivered once it is ordered?

12 weeks

Is there machining on the cone for the new cone nozzles or are the original locations used?

The original cone locations are used, OEM manifold is used, high pressure flex line is installed and the manifold flanges are upgraded from 150lb to 600lb. Drilling and machining on the bellmouth only.

Do you have an option for online soap washes?

No GTE does not recommend soap for online washes. GTE installs a conductivity meter to ensure the water is below 10ppm demin/deionized water for maximum cleaning effectiveness (the deionized water has a magnetic attraction to pull dirt from the blades) The low ppm is like a spot free rinse and leaves no residue as the compressor vaporizes the water around the 10th stage. If soap is used it will collect on the hot stages where the water is vaporized and leave a varnish on the blades encapsulating the dirt and reducing the blade efficiency. Online soap may have an application if there is a bearing oil leak and there is heavy fouling but should be used sparingly. It will only bring the mess further downstream where some will get burnt by the combustor but some will just collect on the downstream blades.

Is the water heated for online washes?

Yes the water is heated for online and offline washes as it helps aid in removing stubborn deposits much like soaking a dish in warm water before you scrub it.

Why do I need high pressure?

The science behind the GTE wash is the atomization of the water to create a uniform droplet size and droplet momentum. This is accurately achieved by using the high pressure system to overcome all system losses - providing the right amount of flow and pressure to properly deliver through the orifice of each nozzle.

Do I need detergent for your system?

You only will need detergent for offline washing. We recommend following OEM recommendations and a ratio of 4:1 or greater depending on the fouling conditions.

Can I feed more than one compressor from the same skid?

In some cases this is possible, but it is not recommended for sites where the piping runs will be greater than 250 feet. Seek engineering assistance from GTE.

Why is droplet size so important?

If the droplet is too small it may evaporate before it hits the compressor blades or continue to follow the airstream. If the droplet is too large, it may lead to erosion of the compressor blades. The droplet mass and momentum are designed to adequately penetrate the pressure wave surrounding each compressor blade and wet the blade. The droplet distribution of this magnitude has an impact force that does not lead to erosion. At the same time, the droplet impact produces a very significant lateral jet to locally scrub the blade surface of fouling materials.

What type of nozzle do you use and why?

The GTE nozzles are individually designed in-house based on our analysis of the CFD modeling. Unlike other suppliers, GTE does not have “catalog” nozzles that are “on the shelf” items. Each of the GTE nozzles are flow and ping tested in order to meet the design criteria based on empirical and theoretical data.

How often should a compressor be washed?

Ideally, a compressor should be washed daily while operating online to maintain air flow in the early stages. Additionally, the compressor should be washed in an offline mode every 800 hours to clean the entire compressor core. Obviously this depends on run time and local ambient conditions.

How long is the cycle for washing?

Online wash will usually last 3-10 minutes depending on set-up. Offline washes are detailed in the CT’s OEM manual.

Where does the water go when washing? Does it drain?

During an online wash the water is evaporated in the compressor. During an offline wash the water is drained through the compressor case drain.

How far back in the compressor will it clean?

It will clean to the last stage in only an offline position. This is not the same while online.

Will we see erosion in the compressor section?

No, we accurately predict and calculate the correct droplet size distribution to prevent erosion.

Can I use the system for fogging or power augmentation?

No, it is not recommended; but we can provide a combination system that will perform multiple functions including fogging and wet compression.

Why should a power plant operator be interested in compressor water wash?

Gas turbine compressors consume a lot of energy in a power generation cycle or mechanical drive. This energy is used to push air through the compressor to mix with fuel, combust and drive the turbine to create torque for power generation or mechanical drive. When the compressor blades accumulate particles in the air, the compressor ability to push air is diminished and the efficiency of the entire cycle is significantly reduced. In extreme cases, up to 10% of air flow and torque are lost. Compressor water washing removes the accumulated particles or fouling and returns the lost performance.

Why is the GTE compressor wash system more effective than other systems?

The GTE system is designed to produce water droplets and place the water droplets in the compressor air flow stream in a manner to effectively clean the compressor blades without adverse consequences, such as erosion. The sizing of the water wash droplets and the position of the spray to enter the compressor core, without forming streams, produces effective cleaning. Other systems do not form proper water droplets or properly position the water wash spray to enter the compressor core and wash the blades.

How long does it take to recover the cost of investment in a GTE water wash system?

Average investment recovery time for the GTE wash system is a matter of a few thousand hours of operation. This is based on a very nominal recovery of 1% and the lowest values for electricity sale and fuel cost. Some systems can pay for themselves in days.

How long does it take to install?

The system is installed in two parts. Nozzles are located in the gas turbine inlet. This operation is normally achieved during a scheduled outage. Placement and final tie in of the skid can be accomplished in a few days.

Can the water wash system be integrated into plant controls?

The water wash skid can be fully integrated into a plant distributed control system or operated manually.

What are typical cycles for online and offline washing?

An online wash is typically a three to six minute cycle, using water only, with the unit operating from FSNL to baseload. A typical offline wash is seven to 15 minutes with a three to six minute wash cycle with detergent and a three to six minute rinse.

Are the existing wash nozzle locations in the turbine inlet used when installing GTE’s water wash system?

It all depends on the machine. Historically, our CFD calculations have warranted a relocation of the existing nozzles to provide better coverage and distribution of the atomized droplets.

Can you guarantee performance recovery?

Absolutely

Contact our engineering team today.