How much water does your compressor wash really use?

When is your primary concern, water usage during compressor washing is understandably low on your list of priorities. However, the two are linked in potentially surprising ways and understanding how much water is being used per wash event can help you cut costs and boost turbine productivity.

Let’s find out how…

What impacts water usage? Key facts and figures

An off-line gas turbine compressor wash requires the turbine to be shut down while a water/cleaning chemical solution is sprayed onto the compressor blades and inner surfaces.

Water is used in this initial clean (and any other cleans required) and all following rinse stages until a minimum level of conductivity is reached.

The amount of water required is dependent on a few variables, including:

• Fouling levels
• Foam levels and how many rinse cycles are required
• OEM specifications regarding conductivity requirements
• Water system capacity
• Flow rate e.g. GE 7FA ~41 GPM rinse flow ‘vs’ Siemens 501F/G ~22–24 GPM
• Operator’s diluting practices

A typical off-line compressor wash uses up to 3,500 gallons of water on large units. This usage can double when using high-foam detergents.

Why does water usage matter?

High water usage has a lot of knock-on effects:

‘Making’ water

Most plants have demineralised water systems (recommended), and although the per-gallon cost is relatively small once the infrastructure is in place, it makes sense to reduce what you need if possible.

Remote and older sites may struggle to meet excessive demand

If accessing water/demineralising it is an issue, you should look at reducing your requirements.

Environmental impact

Using water has an inherent impact on the environment at both ends of the process: obtaining water and disposing of contaminated effluent. There have been cases noted where extreme excess foam from gas turbine compressor water washing has caused sumps to overflow and necessitated the use of vacuum trucks! The less water you use, the smaller your impact on the environment in this regard.

Excessive wash time

If your washes require multiple rinses to flush out excess foam, you extend overall turbine outage time and delay getting your system back up and running. While the water itself is not especially expensive, the lost productivity during every wash event is costly.

Should I cut water usage at my plant?

Ideally, you should only use the water you need. Although in the big picture you won’t save a lot of money on the water itself, it is sensible to focus on effective washing to minimise downtime, resource use and environmental impact.

How to reduce water usage

Some operators will double-dilute their gas turbine compressor cleaning chemicals to reduce foam production. We would never recommend this, as it is a short-term solution leading to longer-term issues, as the compressor will not have been properly cleaned. You will have to carry out another clean in the near future and/or you will shorten the lifespan of your equipment.

Foam is an important part of . It increases contact time for the chemicals to penetrate foulants but also floats, meaning excess foam is tricky to rinse away.

strike the right balance between foam generation and cleaning efficacy. Operators should always follow dilution guidelines, as they have been carefully calculated to achieve the perfect balance. 

The best solution if you’re interested in reducing water usage is to choose a . This switch often reduces water consumption by around 1/3 and sometimes up to 50%. This is because the number of rinse cycles required to reach desired conductivity levels are much lower.

Get in touch

It’s helpful to think about water consumption at your gas turbine site not only in terms of primary costs but the knock-on effect of wash duration. Every minute spent off-line is a minute of productivity lost. However, cutting corners is not recommended as a thorough wash is essential to equipment health and output.

At Rochem, we’ve specialised in gas turbine compressor washing for decades, and our range of is chosen around the globe for its cost-effective, industry-leading results. Our low-foam formulations reduce rinse time and water consumption without compromising on cleanliness, helping you meet your targets.

If you’re interested in any of our products, would like to place an order or have any questions, . We have dedicated agents in your region who’ll be happy to help.