About the Crystalactor for fluoride recovery at Shell Solar in Gelsenkirchen, Germany
Shell is intensifying its activities in the field of solar energy. The Shell Solar factory in Gelsenkirchen (Germany) has been expanded with a new production line that will manufacture solar cells. This means that since 2003 capacity reached 25 Megawatt peak per annum, an expansion of the current capacity by 15 MWp. The productionprocess for solar cells involves the use of hydrogen fluoride, which, when the cells are washed clean, ends up in the wastewater. Shell decided to opt for the Crystalactor™, a sustainable technology with possibilities for fluoride recycling.
Based on the results from pilot tests performed at Royal HaskoningDHV's in-house Technological Research Centre a basic design and detailed engineering plans were made. The installation was delivered and constructed. The operators were assisted during start-up and trained in every day operation.
At Shell Solar, a 4 m high reactor with a diameter of 0.6 m is applied. The industrial waste water contains maximum 1,000 ppm F and some phosphate. The acidic wastewater is neutralised before entering the reactor. In the reactor, calcium chloride is dosed. The calcium reacts with the fluoride in the wastewater and crystallises onto seed material as calcium fluoride (CaF2). The effluent limit of fluoride (< 50 ppm) is easily obtained. Next to fluoride, also phosphate is removed at a large extent.