Bayer process to shrink chlorine production costs and emissions
26 Nov 2009
Leverkusen, Germany - ?Bayer MaterialScience is commercialising two chlorine production processes, which it claims can save up to 30% on electricity consumption compared to conventional production routes. The technologies are already being applied at Bayer facilities in Germany and China and are to be offered to outside companies seeking to reduce the environmental impact of their operations.
Chlorine is an important basic substance in the chemical industry and an essential feedstock in the manufacture of plastics and medicines, for example. Electrochemical chlorine production is currently one of the most energy-intensive and costly processes in the chemicals industry, with power accounting for around 50% of the costs incurred during its production.
The first new method for manufacturing chlorine developed by Bayer with partners is based on the fuel cell principle and recycles chlorine from hydrochloric acid in a closed cycle. Compared to conventional methods, this oxygen depolarised cathode (ODC) route cuts the amount of energy consumed and consequent CO2 emissions by 30%, according to Bayer.
Chlorine is largely produced using a membrane process. However, the electrolysis process employing ODC technology can generate energy savings, as the feeding of oxygen in gas form enables electrolysis to be performed at a lower voltage, explains Dr. Wolfgang Plischke, a Bayer group director.
Bayer is already using this patented oxygen depolarised cathode technology for chlorine production based on hydrochloric acid at its Brunsbüttel site in Germany, in a plant with an annual capacity of 20kt of chlorine. It is also in use in large-scale industrial operations at the Caojing site near Shanghai in China, which has an annual capacity of 215kt of chlorine.
Bayer researchers have also made further advances in ODC technology for obtaining chlorine based on common salt and claims that this method will also achieve energy savings of 30% compared to conventional processes.
“Were 15% of chlorine manufacturing facilities owned by all market players to be converted to this technology, it would be theoretically possible to cut global CO2 emissions in chlorine production by five million metric tons per year,” concluded Plischke. “If this technology were to be comprehensively implemented in the German chlorine industry alone, it would generate savings equal to one percent of Germany’s total power consumption.”
Working with ThyssenKrupp Uhde, Bayer plans to put a first large-scale plant based on common salt and an annual capacity of around 20kt of chlorine into operation by early 2011. It also intends to offer the technology to other chemical companies worldwide.
Indeed, Bayer MaterialScience recently signed a “Memorandum of Understanding” with Chinese cell manufacturer Bluestar Chemical relating to a planned collaboration in the field of ODC technology for chlorine production based on common salt.
