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

Chapter 4
current density resulting in reduced investment costs. For a given total production rate, the
chosen current density determines the number of electrolysers and cells (see example in Table
4.11) [ 63, Euro Chlor 2010 ].
Table 4.11: Number of cells and electrolysers as a function of current density for a bipolar
membrane cell plant with a chlorine capacity of 100 kt/yr
Current density
(kA/m 2 )
Number of
electrolysers
Number of cells
per electrolyser
Total number of
cells
Production rate
in t Cl2 per cell
and year
3 7 164 1148 87
4 5 172 860 116
5 4 172 688 145
6 4 143 572 175
Source: [ 63, Euro Chlor 2010 ]
Achieved environmental benefits
The achieved environmental benefit of this technique is a reduction of energy consumption.
Environmental performance and operational data
The membrane cell technique has developped continuously since its implementation on a broad
scale in the 1980's. The initial developments focused on anode and cathode coatings, membrane
types, reduction of the cathode-membrane gap, electrolyte circulation in the cells and gas
release from electrodes and membranes. In the 1990's, the electric resistance in the cell structure
was decreased by gradually switching from monopolar to bipolar electrolyser configurations.
Due to these developments, there was also an increase in the maximum current density which
can be applied. The impact of these developments on the specific electricity consumption is
shown in Figure 4.4. A consumption reduction of 8 – 11 % at current densities of 3 – 4 kA/m 2
was achieved between 1985 and 2008 [ 63, Euro Chlor 2010 ].
WORKING DRAFT IN PROGRESS
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