ROCHEM^® D-W Generator

PURE WATER IS ESSENTIAL FOR ALL FORMS OF COMPRESSOR WASHING

No matter where gas turbines are used; in ships, aircraft or industry; they need to be kept clean and efficient and the ready availability of high quality demineralised water is essential for compressor washing.

HIGH QUALITY WATER IS VITAL FOR SAFE ANd EFFECTIVE COMPRESSOR CLEANING

All gas turbine and process compressor OEM’s insist on the use of high quality water for both on and off-line compressor washing. Typically OEM’s require water quality with a Total dissolved Solids (TdS) content of not more than 5 ppm TdS.
The Rochem d-w Generator meets and exceeds all requirements.

POTABLE WATER IS NOT GOOD ENOUGH FOR COMPRESSOR WASHING AND SHOULD NEVER BE USED UNDER ANY CIRCUMSTANCES

The use of potable water – which still contains relatively high levels of dissolved solids – for compressor washing can over time result in serious hot end corrosion problems in gas turbines and process compressors.
Tap water or potable water is typically in the range of 300 to 500 ppm TdS thus contains up to ca 100 times the amount of dissolved solids that are allowed by OEM’s for compressor washing.

DEMINERALISED WATER IS IMPORTANT FOR OFF-LINE, CRANK-SOAK WASHING

Although off-line chemical washing and post rinsing is carried out when the gas turbine is unfired and is being turned at cranking speed by its starting system it is still very important to use good quality, low TdS water for chemical mixing and post-rinsing. The reason for this is that some of the chemical solution and post rinse water can accumulate and remain trapped in various parts and pockets of the combustion system and turbine even after the draining process so that when the engine is fired up the potentially corrosive dissolved solids in the wash and rinse water are left behind as the water evaporates to react with the heat to cause accelerated and so-called “hot-end corrosion”.

ON-LINE CHEMICAL WASHING IS A MORE EFFECTIVE, SAFER PROCEDURE THAN PLAIN WATER WASHING

The benefits of using plain demineralised water only for fired washing are very limited and can even cause performance loss because plain water has no ability to chemically break down and remove non-soluble fouling such as oil and unburned hydrocarbons which are, in the main, the root cause of most compressor fouling.
Plain water washing can often result in the “carry through” of deposits from the front stages of the compressor to the hot, mid-stages where the water element is boiled off and the contamination – including dissolved salts – which it is carrying. is then re-deposited to cause hot, sticky or burned on fouling which is then very difficult to remove

CHEMICAL PURITY IS JUST AS IMPORTANT FOR COMPRESSOR WASHING AS WATER QUALITY

A perfect example of what can happen when only demineralised water is used regularly for on-line, fired washing. The oily/carbonaceous deposit has been washed through from the front to the mid-stages of the compressor where the water has boiled off and the removed fouling has simply been re-deposited.
By simply adding a small amount good quality compressor cleaning chemical to the wash water this problem could have been avoided.
Properly designed high temperature compressor wash chemicals are capable of micro encapsulation of the removed fouling to carry it safely to the combustion system where it is burned