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

{Please TWG provide more information.}
Achieved environmental benefits
The achieved environmental benefits of this technique include:
prevention of emissions of ozone-depleting substances;
prevention of emissions of substances with high global warming potential.
Chapter 4
Environmental performance and operational data
At the Dow plant in Stade (Germany) chlorine is used as refrigerant [ 199, Bezirksregierung
Lüneburg 1997 ].
At the Orica plants in Melbourne and Sydney (Australia), the chlorine gas is liquefied by carbon
dioxide evaporating at -45 °C and the carbon dioxide is in turn recondensed by an ammonia
refrigeration unit operating at -52.6 °C saturated suction temperature and 40 °C condensing
temperature. Because ammonia and chlorine are so reactive, they are physically separated from
each other in the plant and in the refrigeration system. The ammonia refrigeration system is
designed to provide cooling to a carbon dioxide thermosiphon loop which then provides cooling
to the chlorine liquefaction process. The advantage of the thermosiphon system is that there are
no moving parts or additional energy inputs. The brake horsepower of the refrigeration system
ranges from 4.4 – 4.5 per tonne of refrigeration. The liquefied chlorine is stored at -41 °C and
atmospheric pressure [ 270, Orica 2011 ].
Cross-media effects
{Please TWG provide information.}
Technical considerations relevant to applicability
{Please TWG provide information.}
Economics
{Please TWG provide information.}
Driving force for implementation
The driving force for implementation of this technique is environmental legislation.
Example plants
Dow in Stade (Germany), chlorine capacity 1585 kt/yr, use of chlorine as refrigerant
[ 199, Bezirksregierung Lüneburg 1997 ];
Orica in Melbourne (Australia), chlorine capacity 31 kt/yr, use of carbon dioxide and
ammonia as refrigerants [ 238, Clews 2001 ];
Orica in Sydney (Australia), chlorine capacity 31 kt/yr, use of carbon dioxide and
ammonia as refrigerants [ 238, Clews 2001 ].
Reference literature
[ 78, Regulation EC/1005/2009 2009 ], [ 198, WMO 2006 ], [ 199, Bezirksregierung Lüneburg
1997 ], [ 200, UBA 2011 ], [ 238, Clews 2001 ], [ 270, Orica 2011 ]
WORKING DRAFT IN PROGRESS
4.3.6 Techniques to reduce emissions to water
4.3.6.1 Techniques to reduce emissions of sulphate
4.3.6.1.1 Overview
In addition to the technique described in the following Section 4.3.6.2.2, the recycling or reuse
of spent sulphuric acid from chlorine drying (see Section 4.3.7) and the use of
non-sulphur-containing reducing agents to reduce emissions of free oxidants (see
Sections 4.3.6.3.3 to 4.3.6.3.6) also reduce sulphate emissions.
TB/EIPPCB/CAK_Draft_1 December 2011 231