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Solvents are unsustainable?
When used in combination with closed cleaning machines, solvents provide 4 distinct benefits that contribute to sustainability:
Nowadays, solvents meet strictest environmental standards and Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) requirements. At the same time, great technological advances in solvent cleaning systems are leading to environmentally sound and responsible cleaning options.
To evaluate solvent use through the lens of sustainability, the performance of the solvent itself is just as crucial as the process and system within which it is used. Taking into account energy usage, solvent recyclability, waste treatment and disposal, as well as chemical impact on the environment, solvents when used in combination with modern closed cleaning machines, may even have a better environmental profile than many other cleaning methods.
1. Virtually no air emissions when used in modern sealed plants
Solvent losses into the air from open top machines used to represent a major portion of organic pollution. However, modern closed cleaning machines running in vacuum conditions1 – for both chlorinated and non-halogenated solvents – means that there is virtually no emission in the cleaning process.
In addition, the application can be fully bundled with closed loop solvent delivery systems which can prevent emission during transfer and handling of solvents from and into the machine.
2. Minuscule solvent consumption and long bath life
In modern, closed cleaning machine, used solvent can be constantly re-purified and nearly completely recycled in the distillation unit. This routine recycling means there is very low solvent replacement volumes necessary. It also reduces health and safety risk, and brings in cost savings not only in terms of solvent consumption, but also time, labor and paperwork due to minimal wastage.
Since solvents can be effectively recycled and reused following distillation, the waste volumes are much lower. Compared to aqueous cleaning, solvents can be easily separated from oils by distillation. The higher the temperature difference between solvent and oils in their boiling points, the better the separation by distillation.
If there is a significant amount of oil that needs to be removed in the cleaning process, the good distillation behavior of solvents can be a great advantage which can ensure minimal wastage and reduced carbon footprint.
Thanks to their low surface tension and viscosity, solvents dry quickly and completely, leaving no moisture or residue on parts after they exit the vapor degreaser. In comparison, energy required to dry metal parts after aqueous cleaning can be 10 times higher.
During the distillation process, solvents also require much less energy to heat to boiling temperature because of their lower specific heat capacity. It also requires less energy for it to evaporate, as illustrated in the table below.
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Every cleaning process comes with its unique requirements and challenges. By no means can solvent be a one-size-fits-all solution. The choice of the right cleaning solution therefore depends on your requirements, goals and expectations. Our free whitepaper "10 key questions to consider when selecting the right cleaning agent" will guide you to make the optimal cleaning decision that balances technical, economic and environmental requirements.
1 Vacuum condition is compulsory for flammable solvents. For halogenated solvents, vacuum condition can be an option, but not mandatory.
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