Unfortunately, compressor fouling is inevitable. Deciding how to deal with it, however, is up to you and it helps to understand what causes it in the first place.
What is compressor fouling?
The term ‘compressor fouling’ describes the build-up of unwanted materials which leave the surface of the compressor blades rough. This happens over time and, if ignored, can cause huge problems including costly unscheduled shutdowns.
Why does it matter?
Although it can be a gradual process, compressor fouling can have a big effect on aerodynamic form. In turn, this reduces the air flow which reduces efficiency; you may notice a drop in compressor discharge pressure and an increased temperature. The really important part though, is that an inefficient system is more expensive to run as it requires more fuel.
Therefore, it’s imperative to minimise compressor fouling as much as possible, while also having a regular cleaning schedule in place to remove any unavoidable build-up.
What are the different types of compressor fouling?
Fouling can be caused by various contaminants entering the compressor system. It’s extremely difficult to entirely prevent it from happening and can be attributed to a number of causes:
This general term describes the deposit of liquid/oil mixtures on the blades. The result is an oily film which in turn attracts particles. These particles may be introduced to the system via exhaust from burnt fuel, oil leaks or even poor quality air polluted with industrial smoke or even car exhaust fumes. Hydrocarbon fouling is considered the worst kind.
Inevitably, there is moisture in the air which enters the compressor. When this air becomes heated, the moisture evaporates, leaving behind a deposit of previously dissolved salt on the blades. As the temperature rises, these deposits become baked onto the blades making them rough and difficult to clean.
Alongside this roughness, the salt can corrode the blade metal and cause rust, which in turn can be a big problem. Salt is a particular problem in terms of compressor fouling offshore and in coastal areas.
It’s essential to wash the compressor to remove fouling but some cleaning products contain chemicals which can lead to fouling themselves if not rinsed properly! That’s one reason it’s critical to choose a specially designed product and use it as directed.
Apart from hydrocarbons, salt and cleaning products, there are numerous other things that can cause fouling. If dust and sand get into the system, they can in themselves erode components and cause fouling if mixed with any kind of oil. Also, air will always have some contaminants such as farming chemicals, industrial gas, exhaust fumes, plant spores and even insects.
What can be done about compressor fouling?
Although it is inevitable that some level of process compressor fouling will occur, the good news is that it can be removed in order to maintain an efficient system. It’s extremely important to carry out regular turbine washing with a specially designed product such as Fyrewash.
Off line and on line washing
Off line washing involves shutting down the system to carry out a thorough, manual clean. It is time consuming and this in turn affects productivity.
Although it is important to carry out off line washes, on line washing is an effective way of reducing the build-up of foulants in the first place. By installing a Rochem on line cleaning system, an effective clean is carried out during normal operation and takes just a few minutes.
Together, off line and on line washing remove foulants to maintain a healthy, efficient and productive system.
Find out how you could reduce process compressor fouling and increase its efficiency. Contact Rochem team to arrange a site visit.