Evaporation is one of the most cost intensive and complex forms of chemical recovery, but sometimes unavoidable. Therefore it is important to keep the flow of this process step as small as possible.

High Density Poly Ethylene (HD-PE) production with hexane as carrier fluid is one example therefore. Typically after the catalytic reaction the HD-PE is fed into a hydro cyclone, whereas through the underflow the majority of worthy product is separated from the liquid, but the overflow of the hydro cyclone still contains a non-negligible amount of product plus wax-like intermediate stages of the reactant and is typically evaporated.

After several unsuccessful trials with disposable filters as well as standard backwash filters, a big chemical company, which is producing HD-PE on two sites in Germany, installed the Lenzing OptiFil^®. Although the particles are very small at 5µm and below, the Lenzing OptiFil^® provides a reliable barrier for the particles leading to the fact that...