Clean decision – what future for trichloroethylene?

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Trichloroethylene has been favoured within the aerospace industry for vapour degreasing of titanium, in certain applications, but the chemical has been facing an uphill battle. Is its Annex 14 REACH listing the end of the road?

Trichloroethylene arrived on Annex 14 of the REACH Regulations in April this year, with the latest phase out, or 'sunset date', 36 months from that time (April 2016). At that point, all operators will be required to substitute an alternative, advises Geiss UK (0151 326 2237), the exclusive UK distributor for Richard Geiss GmbH, a recycling company for both chlorinated and non-chlorinated solvents. There has long been a requirement under existing legislation that operators must substitute trichloroethylene "wherever possible" and "at the earliest opportunity", the company explains. But, it adds, this has been very much open to convenient interpretation, with one of the main drivers having been the requirement for trichloroethylene to be used for the vapour degreasing of titanium, in certain aerospace applications. However, the company offers: "With the approval of Rolls-Royce aerospace of modified alcohols, such as Geiss RG63 [hydrocarbon], clearly substitution in this industry is now possible." The dilemma for many operators having invested in closed systems designed to operate at ambient pressure only (not suitable for alcohols or hydrocarbons) is now clear, it states. Operators wishing to continue to use trichloroethylene after the sunset date must apply for authorisation no later than 18 months following its inclusion in Annex 14 - September 2014. (Of course, those with equipment that can operate at less than atmospheric pressure could swap, if a true alternative is available.) Geiss UK says that "it is known that any licence [authorisation], if granted, would cost a six-figure sum", but that some trichloroethylene suppliers intend to apply for a 'blanket' licence to continue to supply trichloroethylene, "even when alternatives are clearly available". AUTHORISATION EFFORT One such supplier is Safechem Europe GmbH (UK, 07976 531695), a subsidiary of The Dow Chemical Company. Safechem and Dow are preparing to apply for the authorisation of trichloroethylene for use in industrial surface cleaning in 'closed' machines. The pair explain that authorisation will only be considered, if an end user can demonstrate, with data evidence, that no suitable alternative is available. This requires information that lists all efforts to identify possible alternatives, and reviews the technical and economical feasibility, and availability of the substance. Safechem and Dow have started to prepare a dossier to apply for authorisation on behalf of their supply chain, meaning that individual firms need not apply. The application will only include the industrial use of trichloroethylene in surface cleaning in closed cleaning machines considered as Best Available Technology (BAT), as defined by the European Chlorinated Solvent Association (ECSA – Further, it will be limited to applications in which the substance cannot be substituted or substitution cannot be realised before the sunset date, it is added. The dossier has to contain the identity of the substance, contact details, detailed information on use and handling, a chemical safety report, analysis of alternatives, a substitution plan (if a suitable alternative exists) and socio-economic analysis. In approaching this challenge, the pair explain their methodology: "We are currently in the process of establishing the Analysis of Alternatives (AoA) method. This starts from the understanding that all different use cases of trichloroethylene can be described by varying combinations of a set of use parameters. Use parameters are, for example, the presence of complex geometries, temperature-sensitive parts, heavy oil load and so on. "With the help of input from customers, essential use parameters and linked critical cleaning substance properties have been defined and are being evaluated, regarding the feasibility of alternatives. Single-use parameters may well have suitable alternatives, but these may, however, differ for the different parameters in such a way that given combinations of use parameters will not have suitable alternatives. "Following a decision-tree approach, the process will define, in the end, those combinations of use parameters for which no suitable alternatives exist and therefore require continuous use of trichloroethylene. The AoA will be complemented by a Socio-Economic Analysis (SEA), which is being prepared in parallel. "First sessions with ECHA seeking feedback on the draft AoA and SEA reports are envisaged towards end year. "In addition, Dow and Safechem are engaged in communications with customers that gave input to make sure their cases and need for continued use of trichloroethylene are correctly mirrored by our approach, and the AoA and SEA reports." Now, like Geiss UK, Safechem and Dow offer alternatives to trichloroethylene. These take in Dowper MC (perchloroethylene, tetrachloroethylene, PCE), Mecthene MC (methylene chloride, dichloromethane, DCM), and the modified alcohol solvents from the Dowclene series (non-chlorinated solvents, based on modified alcohols). Many of these have approvals for use in aerospace and defence. APPLICATION OUTCOME The outcome of the application for authorisation is one of three possibilities, it would seem. One, that certain specific cleaning operations (use cases) will be allowed; two, that substitution cannot be realised before sunset, but will be realised afterwards, meaning the end of trichloroethylene, but not in April 2016; or, three, that trichloroethylene's time will come in April 2016. Now, even if its use is cleared for certain applications, Geiss UK suggests that cost and commercial viability will be issues. "With the volumes supplied potentially being close to zero, the question of cost of continued availability for the operator and, indeed, commercial viability for the supplier will then become the all consuming questions," it says. So it suggests that a logical choice, for those that can, will be a switch to another of the chlorinated family, such as perchloroethylene, a solvent able to work under ambient pressure conditions (although vacuum distillation and by-pass distillation maximise performance and economy). However, while many existing double-lidded or enclosed systems cannot be deemed to be 'compliant at source' (by bringing consumption to <100 grams/hour and rounded to the now famous one tonne/annum threshold limit), there still remains the possibility of successful conversion, says Geiss. Providing all Health & Safety and environmental legislation, particularly the Solvent Emissions (England & Wales) Regulations 2004, are strictly followed, existing systems can often be converted to accommodate perchloroethylene at relatively modest cost by companies such as Standard Industrial Cleaning Systems (0845 257 1985), it is suggested. The arguments for alternative solvents, such as normal Propyl Bromide (nPB) and methylene chloride, still continue, Geiss UK offers, but close examination of the toxicity issues (R60) associated with the former and abatement problems with the latter render such products questionable at the very least, the company suggests. "Clearly, the volumes of organic halogenated hydrocarbons used in surface cleaning and degreasing within the western world have decreased significantly in the last few years," it says. "The massively reduced requirements of modern hermetically sealed systems, supplied by German manufacturers such as Karl Roll GmbH (Standard Industrial Systems), incorporating vacuum distillation and by-pass distillation, demonstrate frugality in the extreme. Volumes will continue to decline and the real future will be service orientated." Geiss UK Ltd was formed two years ago as the exclusive UK distributor for Richard Geiss GmbH, one of Germany's leading producers of high quality, highly stabilised cleaning and degreasing solvents, and Europe's largest recycler of both halogenated and non-halogenated products. In conclusion, it says: "The demise of trichloroethylene has been debated for many years – the argument is officially over and the way forward is clearer than ever. "Solvent degreasing in efficient plant remains the most environmentally-friendly form of industrial component cleaning [see]. The practice of supply, support, and certificated waste removal and processing by Geiss UK provides the operator with the confidence to know he is involved in a truly sustainable process with service at its core – the future is guaranteed." Safechem and Dow also offer supply and removal of solvents, trichloroethylene or otherwise, in a safe manner. The pair's SAFE-TAINER container offering (above) is a closed-loop system – one container for fresh, another for used. In combination with closed cleaning systems, it is regarded as the Best Available Technology for transport, storage and handling, and enables virtually emission-free use of solvents, the company claims. Individually adapted solutions are offered, with Safechem working with leading cleaning equipment manufacturers, responsible distributors and certified waste managers. So, Geiss thinks the end is nigh for trichloroethylene; Safechem and The Dow Chemical Co are approaching the matter scientifically with their AoA and SEA, which may or may not demonstrate that alternatives always exist. First published in Machinery's Aerospace Supplement, September 2013