Bayer MaterialScience Constructs World-scale Plant for Chlorine Recycling
Sep 21, 2006
SHANGHAI -- Bayer MaterialScience AG is planning to construct world-scale production plants to manufacture the polyurethane raw materials MDI and TDI at the integrated Shanghai plant. The chlorine required to operate these plants is produced on site at the world's largest hydrochloric acid recycling plant. Work is currently in progress on Bayer MaterialScience's new hydrochloric acid electrolysis facility, which offers an annual capacity of 215,000 metric tons of chlorine and is due to be commissioned in 2008. The innovative oxygen-depleting cathode (ODC) technology which has been developed by Bayer MaterialScience and partners will be used at the plant on a world scale for the first time.
Hydrochloric acid occurring as a by-product in isocyanate production is separated during electrolysis into chlorine and hydrogen by means of electricity, with oxygen as a further coreactant. The chlorine obtained is reused for isocyanate production and thus deployed in a continuous cycle. The electrode that depletes the oxygen functions as a cathode, which is why the new process is referred to as oxygen-depleting cathode technology.
Bayer MaterialScience developed the ODC process to industrial maturity together with its partners UhdeNora, DeNora North America and Bayer Technology Services GmbH. In 2003, a hydrochloric acid electrolysis plant equipped with ODC technology was commissioned in Brunsbuttel, Germany, with an annual capacity of 20,000 tons of chlorine. The experience gained in Brunsbuttel is now being put to use in constructing the world-scale plant in China.
The advantage of the ODC electrolysis process is that it saves energy. "The ODC process uses around 30 percent less electrical energy than the diaphragm process established at Bayer for many years," says Dr. Christian Ohm, Head of the Inorganic Basic Chemicals Business Unit, where ODC technology was developed. "The technical principle is the same as a fuel cell process. By feeding in oxygen, we can perform electrolysis at a much lower voltage," he explains further. The new plant is being constructed by Bayer MaterialScience in conjunction with Bayer Technology Services and UhdeNora.
With sales of EUR 10.7 billion in 2005, Bayer MaterialScience AG is one of the world's largest polymer manufacturers. Its main fields of activity are the production of high-tech polymer materials and the development of innovative solutions for products used in many areas of everyday life. The main consumer sectors are the automotive, electrical/electronics, construction, sports and leisure industries. Bayer MaterialScience has production facilities at 40 sites around the world and a workforce of approx. 18,800. Bayer MaterialScience is part of the Bayer Group.
