Last month, Covestro AG (Leverkusen, Germany; www.covestro.com) started up a new world-scale facility for the production of chlorine in Tarragona, Spain. It is the first world-scale production plant for chlorine based upon the oxygen-depolarized cathode (ODC) technology invented by Covestro and its partners. The new plant ensures an efficient, sustainable and independent supply of chlorine and caustic soda to methylene diphenyl diisocyanate (MDI) production in Tarragona. MDI is a precursor for the manufacture of rigid polyurethane foam used to insulate refrigeration appliances and buildings. The €200-million investment has created 50 new jobs on site.
The ODC technology was developed by Covestro in collaboration with thyssenkrupp nucera (Dortmund, Germany; www.thyssenkrupp-nucera.com), with the first demonstration plant started up in 2011 in Krefeld-Uerdingen, Germany (Chem. Eng., May 2010, p. 11). Compared to the currently predominant conventional chlor-alkali electrolysis, the new process requires a lower voltage, which results in energy savings of up to 25% (for more details, see Chem. Eng., October 2018, p. 7). At the new plant in Tarragona, this can avoid up to 22,000 metric tons of CO2 emissions per year compared with existing processes — based on the energy mix at the start of construction planning in 2018, Covestro says.