Safely & Efficiently Treating Stainless-steel Pickling Solutions

Phil Black - PII Editor 09/11/2015

110 3 minutes read

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The more profitable a project, the greater the investment

But it’s not just high savings potentials which motivate businesses to invest in wastewater treatment. The responsibility to protect the environment is also playing a key role for an increasing number of industrial companies.

That’s why thermofin’s main aim was to create a wastewater treatment system which enables sustainable recirculation and pays off quickly. A requirement which H2O GmbH from Steinen in Baden-Württemberg has fulfilled with its VACUDEST XS 360 vacuum distillation system.

The first contact between heat-exchanger manufacturer thermofin, based in the Saxon town of Reichenbach, and H2O GmbH, from Steinen in Baden-Württemberg, was made at the Pulversymposium in Dresden. Even at this early stage, it became clear that, with disposal costs of up to 400 Euros per cubic metre of wastewater, a lot of money could be saved through wastewater treatment.

The graph shows how fast the investment in VACUDEST XS 360 will pay off for thermofin: just 1.1 years.

Thermofin specialises in manufacturing industrial heat exchangers, which are produced as per customer requirements in lengths of up to eight metres. The reputable company’s customers include the Electoral Palace in Dresden, the Saudi Electricity Company in Riyadh, the Hamberger gastronomy wholesaler in Munich and the SnowDome indoor skiing facility in Bispingen (Lüneburg Heath). Thermofin’s heat-exchanger manufacturing processes result in stainless-steel pickling solutions, as well as rinse water from powder-coating pre-treatments. Around 300 cubic metres of wastewater are produced each year.

Saving potential — The profitability calculation is impressive: in 10 years of operation, thermofin will save over 1 million Euros with its VACUDEST.

Calculation of amortisation time and saving

This wastewater from the stainless-steel pickling solution and the rinse water from the paint pre-treatment has previously been collected by a local disposal company and charged at a rate of up to 400 Euros per cubic metre, resulting in additional production costs of over 100,000 Euros a year. The laboratory trial conducted at H2O’s application centre for wastewater-free production found that wastewater quantities can be reduced by up to 98 percent. This 98% saving in disposal costs means the investment’s profitability quickly becomes apparent.

Inspection of an operating customer system

VACUDEST XS — Tight spaces are not a problem for H2O GmbH’s engineers: The tanks were quickly placed on top of one another to save space in the production facility.

After the head of powder-coating pre-treatments department Thomas Speck expressed interest in seeing an H2O system in use at a customer facility, a visit was made to the production plant of Kaeser Kompressoren in Gera in April. He was thrilled with the clear structure, component layout and positive feedback from production managers: “Clean treatment like this would also work well at thermofin!”.

He was particularly impressed by Kaeser’s ratings of the system’s profitability and reliability, and the results in terms of treatment and distillate quality. The system yields the exact results promised in the laboratory trial – which is very crucial when it comes to reusing the distillate.

The plan for treating and reusing the process water at the production plant was efficiently formulated, allowing both companies to meet for contract negotiations as early as May.

The wastewater treatment for the thermofin project went off without a hitch. The components and system were efficiently installed in August, thanks to H2O’s excellent planning. The tight space behind the powder coating area of the production plant posed a setup challenge; the VACUDEST XS 360, including tanks and residual oil separators, had to be installed in an area of just 3.3 x 4.0 metres.

As space was tight on the side, a vertical layout was opted for, resulting in both tanks for neutralisation and distillate being placed on top of one another. The space provided was maximised. The production managers’ great interest in completing the project as quickly as possible also helped. Production manager Thomas Speck was always open to H2O’s queries and able to assist.

thermofin has been saving on disposal costs for production wastewater since early September. The initial results have been very promising, and even managing director Bernd Löffler is pleased: “Thanks to VACUDEST, we are saving so much wastewater every day that the investment will soon pay itself off. We are delighted that the product could be carried out so quickly and smoothly, and that we can also help protect the environment.”

Energy Recycling — 95% energy recycling ensures cost effectiveness.

How does vacuum distillation work?

This water-treatment process offers many other benefits in addition to recirculating rinse water. The used process water is evaporated in a vacuum at approx. 86°C. The resulting steam is compressed to normal pressure in the vapour compressor and heated to approx. 120°C. This hot steam is then used to heat and recompress the process water in the tube bundle heat exchanger, saving more than 95% energy compared to atmospheric evaporation. The resulting distillate is virtually free of any salt and heavy metals, and only needs to undergo ion exchanger treatment before it can be recirculated as rinse water: wastewater-free manufacturing!

Author:
Thomas Nadler
Area Sales Manager Bavaria & Austria
H2O GmbH Steinen, Germany

H2O GmbH
Wiesenstrasse 32, 79585 Steinen, Germany
Phone +49 7627 9239-0 | Fax +49 7627 9239-100
Email info@h2o-de.com | Web www.h2o-de.com