Case Study 4: Lenzing AG - Evaporator Optimisation

Copyright Lenzing AG

Copyright Lenzing AG

Success Story:

partner-logo-lenzingThe Lenzing site, located in Lenzing, Austria, is a reference factory around the world for producing man-made cellulose fibers. These advanced fibers are broadly employed: since home textiles up to medical and technical applications. Large amounts of energy and chemical feed materials are required to obtain fibers with desired chemical and mechanical properties. One of the steps in the fiber production uses a product called spin bath, which is a solution of H2SO4 plus several SO4 salts. Then, this product needs to be concentrated in order to reduce the amount of water in the solution to crystallize and, thus, recover Na2SO4 for reuse. The evaporation takes place in several multi-effect evaporators with high steam consumption.

Within the project MORE new models in combination with the use of resource efficiency indicators were created. Meanwhile, the optimisation of single evaporators resulted in energy savings of about 1 million m3 natural gas per year which is equivalent to a reduction of CO2 emission by 2700 tons per year. Additionally, the optimisation of the cooling towers, closely connected to the evaporators, led to energy savings of about 250.000 m3 natural gas per year – equivalent to nearly 700 tons less CO2 emission per year. The reduction of CO2 emission is phased with our acting as a producer of sustainable man-made cellulose fibers. Up to now, savings of more than 300 k€ per year are realised by the implemented MORE results.