Everything you need to know about cleaning chemistry
08.19.24
You may be surprised to learn how much chemistry goes into cleaning. However, selecting the right combination of chemicals in precise quantities and applying them to maximum effect is literally an exact science.
The cleaning circle
It all starts with a basic understanding of the cleaning circle, also known as ‘Sinner’s Circle’. This principle shows that cleaning effectiveness is dependent on four codependent key factors:
Time
How long the wash takes i.e. the longer spent cleaning, the better the results.
Mechanical action
The physical act of cleaning e.g. hosing, wiping, scrubbing, brushing.
Temperature
The temperature of the cleaning environment/wash fluid and its impact on chemical reactions. Higher temperatures usually mean quicker reactions.
Chemical action
The chemicals themselves and how they break down or s.
The cleaning circle shows us that these four factors rely upon and are affected by one another. For example, if you increase the temperature, you may be able to decrease the concentration of your cleaning solution; if you increase the mechanical action, time can be reduced and so on.
With an understanding of the cleaning circle, you can balance the four key factors while considering your costs and environmental impact.
Key cleaning terminology
Like any science, cleaning chemistry uses terminology which enables us to be precise when designing and discussing our products.
pH
The pH of something is given as a numerical value from 0-14 and tells us how acidic or alkaline it is; 7 is neutral, below 7 is alkaline and above it is acidic.
In cleaning chemistry, strong acids are used for descaling while strong alkalis for degreasing and it’s important to get that balance right. FYREWASH® chemicals in combination with water are all in the pH range of 7.2 - 7.9.
Surfactant
Surfactants (short for ‘surface-active agents’) reduce the surface tension between two substances. They’re essential to effective cleaning and play many roles:
- Water spreads further and quicker with reduced surface tension.
- Emulsification: the hydrophobic tails of surfactants are attracted to oil, but the hydrophilic tails are attracted to water. This results in oil/grease molecules being surrounded by the surfactant and forming micelles which are suspended in the cleaning solution and washed away.
- Some surfactants create foam which can aid the lifting and removing of foulants.
Careful surfactant choice is key to all cleaning products. It means dirt is effectively removed, kept in solution and rinsed away.
Our different all employ surfactants to optimise the efficiency of the chemicals. They are externally tested to assess their wetting properties, enabling us to optimise their performance: good wetting on the blades = increased surface contact time. As we learnt from the cleaning cycle, increased contact time results in improved cleaning.
Cloud point
The cloud point is the temperature at which the cleaning solution turns ‘cloudy’. This is because non-ionic surfactants in the solution become less soluble in water as the temperature increases. The surfactant molecules begin to clump together, turning the solution cloudy and, as the temperature increases beyond the cloud point, the surfactant becomes insoluble in water.
At and beyond the cloud point, cleaning chemicals are less effective as the surfactant can no longer remove oils. Understanding the cloud point goes back to the cleaning circle: while higher temperatures generally improve cleaning, a too-high temperature will impact the effectiveness of the products.
In the context of gas turbine compressor cleaning, this is most relevant to as off-line cleaning is carried out at temperatures below the cloud point of FYREWASH® chemicals. Using our understanding of cloud point, we have designed our products to suit the high temperatures of gas turbine compressors and offer clear guidance on the best temperate ranges for optimum results.
Boiling/evaporation point
The boiling point is the temperature liquid changes to vapour while the evaporation point is when liquid begins to evaporate (pre-boiling). Note that only pure materials have a fixed boiling point while mixtures have a boiling range.
Gas turbine compressor cleaning is often carried out at very high temperatures which is why FYREWASH® chemicals are designed to have high boiling and evaporation points. Premature evaporation would lead to reduced contact time for effective cleaning. This leads right back to the cleaning circle again: more contact time gives better results.
Foam
Foam is trapped pockets of air in a liquid or solid. When it comes to cleaning, getting the foaming level correct is essential: foam increases the chemical’s contact time with the turbine blades but also adds rinse time as it floats on waste water.
During FYREWASH® product development, foaming behaviour is a benchmark test and we offer low/no foaming products as a result of years of research.
Find out more
So, there you have it: our crash course in cleaning chemistry. We’ve been in the gas turbine compressor cleaning business for decades and rely on our knowledge of cleaning chemistry to create our market-leading product line: FYREWASH®. We hope this introduction gives a little insight to the science behind FYREWASH® and why it’s so good at what it does.
If you’re keen to find out more or would like to discuss using FYREWASH® products at your site, . We’ll be happy to answer all your questions.
Post written by Martin Howarth
An extensive knowledge of mechanical and electrical engineering together with hands on experience with gas turbines provides a bedrock for his work at Rochem.
