A.   There is no finite answer to this question. The interval between washes will be dictated by the site, the degree of air pollution, the amount of fine particulate matter in the air, and of course the power loss acceptable to the operator. In order to ascertain the site requirement, we recommend starting with two on-line washes a week, with an off-line wash every two weeks. Depending on the results, these can be varied to obtain the degree of power loss acceptable to the operator.

Q.   How do I know if the wash has improved performance?

A.   Ideally if you can measure accurately the compressor inlet and discharge pressures/temperatures, this would be the criteria by which to judge the improved performance.  Sadly this is seldom the case. It is better to judge the performance improvement by the fall in exhaust gas temperature (EGT) after a wash. If the EGT is measured at a specific power setting before and after a wash, a more efficient (i.e. cleaner) compressor will show a fall in the EGT. There should also be a fall in the fuel flow.

Q.   Why do I need to wash?

A.   The compressor of a gas turbine ingests a large amount of air. This air contains particulate matter, aerosols of hydrocarbons and other organic compounds and gases of industrial production such as nitrogen, chlorine and sulphur. Although the larger particulate matter is filtered out, the other compounds and the fine particulate matter are deposited on the compressor blades. This alters the aerodynamic profile of the blades and leads to a fall in compressor efficiency. Compressor washing removes this deposited fouling, restoring the aerodynamic profile and compressor efficiency.

Q.   Can I pass the product into an oil/water separator?

A.   When diluted to the recommended ratio the product can be processed through an oil/water separator.

Q.   Is the product biodegradable and can I discharge it to drains or watercourse?

A.   The product is biodegradable. The question regarding discharge into drains/watercourse is a matter for local authorities. Before discharging, obtain a permit of discharge from the local water authority.


Q.   What are the advantages of a water based fluid?

A.   They have less impact on the environment and are safer in use. They are biodegradable and where permitted, can be discharged to a watercourse. This eliminates the need to collect the washings for disposal when cleaning off-line. These are also safer for operators to use, as there are no solvents containing aromatic hydrocarbons present. Therefore only minimal protective clothing is required during cleaning. Please see Health and Safety Sheet (MSDS) for details.

Q.   In what way can on-line washing improve efficiency?

A.   On-line cleaning is not as efficient as off-line cleaning and eventually all gas turbines will require an off-line wash to restore power. The idea of on-line washing is to extend the period between off-line washes by regaining most of the power lost between on-line washes, thereby slowing down the degradation and extending the period between off-line washes. On-line washing should be carried out at a frequency that maintains the compressor as close to maximum efficiency as possible.

Q.   When washing on-line, why do I not see any difference in power recovery whether I use demineralised water or a cleaning chemical?

A.   Compressor cleaning chemical should give more power recovery on-line than demineralised water. The crucial factor is the injection system. As the dwell time for cleaning chemical on-line is very short, it must therefore be presented to the compressor in the right way and condition. The position of the injection system and the size of the fluid droplets is also important. Most off-line systems are not positioned correctly for on-line washing, nor do their injection nozzles give the correct droplet size for on-line cleaning. The result of washing with these is that there is no gain in efficiency by using compressor cleaning fluid over demineralised water. If you have this problem and are serious about on-line cleaning, consider adding a dedicated on-line cleaning system.

Q.   What kind of equipment do I need to carry out compressor cleaning?

A.   You will need an injection system of one type or another. If you wish to wash a small helicopter engine, then you may only need a small portable hand held lance or ring with a pressurised container and an atomising nozzle. For a large fan engine, a ring that will wash the engine core will be be required, while the fan is clamped. The washing rig will need to be portable and contain a tank, pump and valves. For industrial engines there are separate fixed nozzle rings for off-line and on-line cleaning. There are also fixed/portable washing rigs which may be fully automated. We do not manufacture injection systems but we can recommend manufacturers who produce efficient systems.

Q. I need to know how much compressor cleaning fluid I should inject into my engine. What quantity should I use and what should the flow rate be?

A.   The information that you require will be found in the maintenance manual for that particular engine ( in the compressor cleaning section). If you do not have a copy, you should contact your engine manufacturer. In the rare case that you cannot get the information that you require then we can recommend dosage and flow rates. However, we recommend that you follow the manufacturers instructions where possible.