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VOC'S OR CO²'S WATER OR SOLVENT
We are constantly being bombarded by new updates on the SED (Solvents Emissions Directives) with what some class as stealth taxes being charged for certain information sheets or new fees to become registered if you are outside of the threshold. Alternatively we are told from Health & Safety Executive or local authorities that you MUST change from Trichloroethylene to an alternative “As Soon As Possible” because of its Health and Safety implications, since it has been re classified as an R45 “May Cause Cancer”.
We, like most responsible people in industry would agree 100% with the desire to use products or processes that are safe and environmentally friendly, that is logical. The problem comes when the information stream is either ambiguous or biased without good scientific reasoning. Most of the reasoning is being based on what is politically correct rather than what is commercially viable within the confines of what is safe and environmentally necessary.
Arguments rage on what is better, the use of solvents with the environmental impact of increasing the VOC's (Volatile Organic Compounds) using the Pollution Prevention and Control Act 1999 and the amended regulation 2000 Schedule 1. The reason for this legislation was to reduce emissions to the atmosphere of VOC's and to minimize the impact on the environment, very commendable.
The solvents industry to a certain extent have brought this on themselves and with the exception of one or two very sensible manufacturers have until the last year or so done nothing to help their customers to reduce their solvent consumption. When, if ever, has your existing supplier visited you and suggested ways to reduce your solvent consumption dramatically. Most have been aware of the problem for at least 7 years and the technology has been available to reduce your consumption by 90% for at least 6 of those years in most cases. This is just a personal opinion which may be wrong but I ask you, what is the incentive for a company supplying 100 tonnes of a particular solvent, to reduce that volume to 10 tonnes or even less to a particular customer? |
Morally it may be necessary but until legislation forces the issue then the supplier may be forced to look at the commercial implication rather than the moral or ethical arguments. If the only available technology were the old fashioned vapour degreasing baths then I would say 'why change'. However modern technology equipment is capable of reducing, in most cases, consumption down to compliant levels, certainly reductions of 20 – 50 plus tonnes are now common place. Modern equipment also has emissions of between 0.05 – an average of 6 ppm's with the average consumption volumes well below 2 tonnes. This is not only safer but also environmentally friendlier proven by the fact that the VOC reduction levy which the Uk Government signed up to has been achieved and in fact this quota has been set lower still.
However what about the CO²s (carbon dioxide) levels? CO² levels relate to energy consumption, generally the more energy you use the more CO²s you generate (some say adding to global warming). It seems unusual that since industry has been forced to convert away from solvent to aqueous options, that CO² levels have been increasing dramatically and recently the quota has had to be increased yet again. Is it unusual when you consider the increased energy that a water based system requires?
A recent customer assessment emphasized this. Admittedly the tank sizes were quite large but not unusual in industry. The basket sizes were 1500mm x 500mm x 1000mm. The overall footprint for 1 cleaner stage, 2 rinses and a drying stage was approximately 4 meters in length x 2 meters deep. The energy required to heat this up and run the drying stage was around 100KW per hour (obviously once temperature had been reached this consumption would or should be dramatically reduced) It consisted of four process stages at 21KW and 1 drying stage at 15KW. Process times per basket around 20 – 30 minutes including the drying stage. The equivalent solvent system used approximately 15KW to heat the solvent to vapour level and thereafter used approximately 7KW per hour. Basket loads would come off every 5-8 minutes clean and dry. The footprint was approximately 2.250 mm x 1500mm. The bonus was that the equipment used as little as 1.6 liters per week of solvent well below the SED legislation and well within the safety confines with ppm readings of an average of 5ppm.
Whilst I would agree there are times when the aqueous option may be preferred I find great difficulty in justifying their use against solvents when the safety of both the operators and the environment is not compromised
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