(BAT) Reference Document for the Production of Chlor-alkali ...

Chapter 6
It is not possible to retrofit air and oxygen-depolarised cathodes into existing membrane cells.
Technical considerations relevant to applicability
The ODC technique can be used in new installations. The retrofitting of existing membrane cell
plants is also possible provided that parts of the electrolysers are adapted. In 2011, however, the
ODC technique is specific to a single electrolyser's manufacturer who will begin to
commercialise it in 2013. Practical experience with a new plant of industrial scale and with
retrofitting of existing plants needs to be gained [ 3, Euro Chlor 2011 ], [ 49, Euro Chlor 2010 ].
Economics
The economic assessment of the ODC technique versus conventional membrane cell technique
depends on a number of factors such as the costs for electricity, new electrolysis cells, ODCs
and required oxygen on the one hand as well as type and degree of hydrogen usage on the other.
Moreover, it has to be considered whether a new plant or the conversion of an existing amalgam
or diaphragm cell plant is planned. It is therefore difficult to draw general conclusions without
taking into account the integration of the ODC technique into the whole plant [ 49, Euro Chlor
2010 ], [ 52, Moussallem et al. 2008 ].
Investment costs for the conversion to the ODC technique were reported to be in the range of
EUR 70 – 100/t annual chlorine capacity. Assuming that the co-produced hydrogen is burnt,
that the costs for the production of pure oxygen are between EUR 0.054 – 0.063/m 3 (at standard
conditions) and that the electricity price is EUR 60/MWh, the ODC technique was reported in
2009 to be economically viable [ 113, Moussallem et al. 2009 ]. However, if the co-produced
hydrogen is used for chemical reactions, the ODC technique was reported in 2011 to be not
economically viable [ 115, Jörissen et al. 2011 ].
The future economic assessment depends on the evolution of electricity prices which in turn
depend on the world energy markets, which could also be affected by carbon trading and
possible carbon dioxide taxes. In addition, the evolution of the 'hydrogen economy' could
transform the hydrogen from a co-product to a premium fuel, easily saleable on the hydrogen
market [ 52, Moussallem et al. 2008 ].
Driving force for implementation
The driving for for implementation is a reduction of costs related to energy consumption.
Example plants
Bayer/Uhde in Leverkusen (Germany), chlorine capacity 20 kt/yr, put into operation in
summer 2011;
Two demonstration units in testing in Japan.
References: literature
[ 3, Euro Chlor 2011 ], [ 49, Euro Chlor 2010 ], [ 51, Bulan 2007 ], [ 52, Moussallem et al.
2008 ], [ 53, Bulan et al. 2009 ], [ 113, Moussallem et al. 2009 ], [ 115, Jörissen et al. 2011 ]
[Gestermann-Ottaviani, 2000], [Wienkenhöver, 2000], [Gestermann, 1998], [Kirk-Othmer,
1991]
WORKING DRAFT IN PROGRESS
294 December 2011 TB/EIPPCB/CAK_Draft_1