Best practices for wash nozzle selection and maintenance

are integral to effective . Carefully selected, properly installed nozzles deliver optimum amounts of cleaning solution exactly where it’s needed for a thorough clean. Consequently, wash nozzles enable you to keep your compressor running effectively and efficiently with minimum effort.

But how do you choose the right nozzles, and how do you get the most from your hardware?

What are gas turbine compressor wash nozzles?

inject atomised cleaning fluid directly into the compressor to clean its blades. Some nozzle models can be operated automatically while the turbine is in normal operation to provide superior cleaning and maintain turbine efficiency. Others will only function while the turbine is shut down in crank mode.

Nozzles are also available and will run while the turbine is in either state online or offline, reducing the amount of hardware required.

Factors to consider when selecting wash nozzles

While this is a niche market, there are important factors to consider before deciding exactly which wash nozzles to choose:

Turbine size

The size of your turbine will affect which nozzles you choose. Larger turbines generally require higher capacity nozzles which can offer broader spray patterns and greater flow.

Type of cleaning

Some wash nozzles are designed for either , while others can complete both. You need to decide whether you want to use them while the turbine is running, while it is off/in crank mode, or whether you prefer the option to use the same nozzles in both circumstances.

Nozzle design

The nozzles must be able to withstand the demands of their location: high pressure, extreme heat and certain chemicals. They must also be capable of delivering the ideal droplet size and spray pattern for optimum cleaning.

Maintenance

What effect will installing the nozzles and maintaining them have on your turbine’s productivity?

Cost efficiency

Does the money saved in turbine efficiency and reliability outweigh the initial outlay and maintenance cost of the nozzles, their associated hardware and cleaning chemicals?

How to install wash nozzles

Once you’ve decided on how many nozzles are required (the turbine’s manufacturer handbook can help with this calculation, as can the nozzle manufacturer/dealer), you’ll need to consider the following for installation:

• Positioning and orientation: evenly spaced, pointing in the direction of airflow, angled towards the blades.
• Connection: ensure the nozzles are securely connected via pipes to the wash skid. Check for leaks.
• Pressure and flow: check the manufacturer's specifications to set the correct water pressure and flow rate.
• Test: test the whole system to ensure it works as expected. Check the flow rate and spray pattern to make sure the compressor blades are fully wetted. Observation windows make testing and monitoring much easier.

Wash nozzle maintenance

To avoid any blockages, (due to high water pressure), corrosion (depending on the environment) and contamination (due to oil leaks from compressor rotor inlet bearing), you should regularly inspect and clean the nozzles, set the water pressure correctly and use demineralised water. As an added precaution you can install a to ensure further contaminants are removed and the nozzles are kept clean.

Recommended cleaning schedule using wash nozzles

The cleaning schedule you use will be led by your turbine, how often it is used, its load, the local environment, air quality, , speed at which foulants build up, the cleaning chemicals you use, whether you choose de-mineralised water, and many other factors. However, as a rule of thumb we recommend:

• Daily on-line washes
• Off-line washes (turbine in crank mode) approx. every 3 months (dependant on condition)

With this as a guide, regular visual inspections of the compressor for signs of fouling will help you adjust your schedule as required/desired.

Wash nozzles are an investment

that can be used for both on-line and off-line washes make cleaning quicker, easier and more effective. Without them, you are entirely reliant on hand-washing during turbine down-time which is costly in terms of labour and revenue.

Regular on-line washes can maintain a high level of turbine efficiency and reliability while extending the life of your hardware and the time between off-line cleans.

Rochem wash nozzles

At Rochem, we have specialised in gas turbine cleaning equipment and chemicals for over 40 years. Our patented technology enables superior cleaning and recovery of lost power output via both on-line and off-line washes. Our nozzles:

• Operate on-line and off-line
• Are designed for gas turbine engines in the range of 0.5-250 MW output
• Can replace existing nozzles or be retrofitted in most cases

Get in touch

If you would like to find out more about the benefits of using Rochem’s gas turbine compressor wash nozzles or are interested in our products and services, please h. Our friendly, will be happy to answer all your questions.