Turning Danube water into pure process water. The reverse osmosis facility at the Slovnaft oil refinery in Slovakia utilises 630 Lewabrane RO B400 HR membrane elements for water treatment. It contains between 320 and 400 mg/l dissolved solids with seasonally fluctuating organic fractions, and it displays an electric conductivity of up to 580 μS/cm.
In the subsequent cleaning stage, moreover mixed bed ion exchange resins from Lanxess’ Lewatit line are used to remove any remaining ionic compounds. The system has a permeate yield of up to 85 percent. The ‘threestage’ demineralization facility can turn out up to 135 cubic meters of permeate per hour and line, and the maximum conductivity falls far below the target value stipulated by the operator of 15 μS/cm. The facility produces fully demineralized water that is available as boiler feed water for watersteam circuits and identical technical purposes. Cologne/Germany -The raw water for the plant is sourced from the Danube. While During treatment, it first undergoes chemical pretreatment and ultra filtration, that is divided into five separate lines, every equipped with 126 membrane elements, before continuing on to the reverse osmosis system. Accordingly, therefore this meant less of a burden on the mixed bed ion exchange resins.
We met all these expectations, and that’s exactly what makes us very optimistic about easily fulfilling all the performance guarantees we granted to the customer, confirmed Alexander Scheffler, Director Membrane Business in the Lanxess Liquid Purification Technologies business unit. Calculations with the LewaPlus design software, developed specifically for Lewabrane and Lewatit products, already showed in the planning phase that permeate conductivities of less than 10 μS/cm will be expected. Compared to the other membrane elements used in previous years, the new system displays significantly longer dwell times. Normally, the magnitude of pressure decline and the conductivity did not increase with the elements from LANXESS until after four months, we used to have to go through the cleaning regimen any four to six weeks. Overall, the longer intervals between cleanings reduced the consumption of cleaning chemicals and increased the availability of the RO lines.