Vacuum Distillation Plants for the treatment of emulsions and oil containing waste water
?The innovative ClearCat-Technology allows separation of dissolved
hydrocarbons and free oils without additional process steps As an alternative to disposal of spent coolants and other oil containing waste waters distillation is a feasible and state of the art processing technology. The distillate can be reused for the preparation of fresh emulsions, can be used for other purposes in the work shop or can be disposed off into the public sewer.
In metal processing work shops many oil containing waste water streams occur. Emulsions for different processing technologies contain among others, oil, wax, fat, and preservatives as well as ingredients improving product properties. After being used up these emulsions often are disposed off at high cost.
Starting from 150 m? per year such waste emulsions can be processed feasibly by vacuum distillation resulting in important reduction of disposal cost. As a general rule ROI periods of less then 2 years are achieved.
The distilled water leaving the vacuum evaporator can either be reused in the work shop, to produce new emulsions for instance, or disposed off into the public sewer. Both variants require excellent water qualities. When using conventional evaporation systems significant amounts of hydrocarbons and free oils are carried over into the distillate. Thus distillate post treatment using coalescence separators, active carbon filters or membranes is required to match legal disposal limits or quality standards for internal reuse of the distillate.
?? Advantages of the VACUDEST ClearCat technology compared to common
Undercut of legal limits for disposal into the public sewer regarding carbohydrates without post treatment of the distillate in all cases up to now
Reduction of COD by 98.2 % in average*
Excellent distillate quality, free of germs, free of heavy metals, almost free of salts Low running cost
Simple, reliable process
Is applicable for changing emulsion compositions
Lowest amounts of residues, thus lowest disposal cost
Statistical average based on a field study of the H2O GmbH. The COD reduction depends on the chemicals used.
Thanks to the innovative H2O ClearCat?-Technology these additional process steps are not needed any more, since crystal clear and virtually oil free distillates are produced. All users so far could either reuse or dispose of the distillate directly, without any further treatment.
?The innovative H2O ClearCat-Technology (figure 1) is available since beginning of
2007. Thus it is adequate to present results from practical experience. It was
??announced that the new VACUDEST ClearCat series for the processing of oil
containing feeds would produce improved distillate qualities at similar
concentration factors and reduced consumption figures. Could the evaporation plant keep all these
promises in industrial practice?
Promise 1: Crystal clear distillate
In the meantime the H2O laboratory screened more than two dozen distillate samples
??from different VACUDEST ClearCat evaporators. About the same amount of samples
have been analysed by the end-users themselves.
??The innovative VACUDEST ClearCat System from H2O GmbH
?The innovative ClearCat technology, based on physical and catalytical processes,
achieves drastic hydrocarbon reductions. No consumption materials or chemicals are
?needed, thus the ClearCat is extremely feasible and maintenance friendly. Even though expensive active carbon and maintenance intensive residual oil adsobers are not needed
??any more the distillate leaves the VACUDEST ClearCat vacuum distillation unit crystal
clear and virtually free of oil. The distillate can either be reused in the work shop or disposed off into the public sewer.
Whilst distillates from common evaporators show considerable milky turbidity and free
?oils, unexceptionally all ClearCat distillates have been colourless clear without any
noticeable turbidity. No expensive post treatment is required; the distillates can instantly be reused or disposed off into the public sewer.
Promise 2: Distillate free of oil according to DIN ISO 9377-2
All samples show extremely low carbohydrate values and undercut the demanding legal disposal limits according to the German water resources law by far. As can be seen in Figure 2, even the limit of 5 mg / l which becomes valid in France eventually in the future was undercut in all cases. Carbohydrate reduction in the distillate was up to 99.9 %.
Promise 3: Additional COD reduction of more than 25 % in the distillate compared to
?common evaporation plants without ClearCat technology
To prove additional COD reduction a field study was carried out. The total COD reduction
??was examined. All samples came from VACUDEST ClearCat evaporators installed in
metal processing workshops all over Europe. Even experts were surprised by the results.
??As figure 3 shows the COD reduction achieved by the VACUDEST ClearCat technology
was in average 98.2 %. This is by 63 % better than results achieved with common evaporators and more then twice as much as initially expected. Thus even strict COD limitations for disposal into public sewer can be undercut often in industrial practice without post treatment. An example is the COD reduction in a coolant emulsion from 50.000 to 900 mg/l in the distillate.
?Conclusion: The ClearCat-technology sets new benchmarks
?The ClearCat-technology is momentarily the most interesting and most feasible possibility available on the market to treat oil containing waste water. Not only emulsions, degreasing water and die casting emulsions but also oil containing waste waters like penetrants can be treated feasibly.
Advantages of Vacuum distillation using the VACUDEST?-Process
compared to other process for treatment of industrial
Robust operating with various waste waters dissolved, emulsified and suspended substances are separated mineral or synthetic emulsions can be split
No use of chemicals for splitting no dangerous handling, no extra costs no extra increase of concentrate
High final concentration of distillation residues low water content with residues easy disposal by incineration
Low energy requirement with the process and vapour compression only 80 Wh/l, approx. 10 ?/m?
Distillate is free of salts, heavy metals and minerals salts such as nitrite/nitrate are not vaporized heavy metals and minerals such as copper, nickel, zinc etc. remain in the residue
Sterilisation of the distillate in the vacuum pump through high temperature approx. 110-120 ?C
Distillate can be reused in the system dissolved substances such as salts and heavy metals are not concentrated further
Extremely compact design minimal size allows operation at the source of process waters maximum service possibility
Constant quality of distillate constant results/performance by varying process water concentrations
Easy operating mechanical system, easy operating controls, minimum
maintenance no membranes, no chemicals