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

Environmental performance and operational data
{Please TWG provide information.}
Chapter 4
Cross-media effects
Some raw materials and energy are consumed for the manufacture of the cooling system
including the heat exchangers. Fouling of the heat exchanger surfaces caused by impurities
contained in the gas and the cooling water reduces the energy efficiency of the heat exchange.
Technical considerations relevant to applicability
Generally, there are no technical restrictions to the applicability of this technique.
Economics
Economics depend on plant-specific factors. Any additional equipment or energy consumption
will increase costs. Savings result from reduced consumption of water which is often
accompanied by a reduced consumption of salt.
Driving force for implementation
The driving forces for implementation of this technique include the following:
reduction of operating costs due to reduced consumption of water and salt;
limited availability of water resources;
environmental legislation.
Example plants
Closed-circuit direct cooling of chlorine and hydrogen is generally used by chlor-alkali plants
[ 3, Euro Chlor 2011 ].
Reference literature
[ 1, Ullmann's 2006 ], [ 3, Euro Chlor 2011 ], [ 124, COM 2011 ], [ 132, Germany 2000 ]
4.3.2.2.5 Concentration of brine filtration sludges
Description
This technique consists in concentrating brine filtration sludges in filter presses, rotary drum
vacuum filters or centrifuges. The residual water is fed back into the brine system.
Technical description
This technique avoids flushing the sludge with a weak hydrochloric acid solution to the waste
water treatment unit, thereby reducing the consumption of water and acid and emissions of
chloride (see Sections 2.5.3.1 and 3.4.2.4).
Achieved environmental benefits
The achieved environmental benefits of this technique include the following:
reduction of water consumption;
reduction of acid consumption;
reduction of chloride emissions.
WORKING DRAFT IN PROGRESS
Environmental performance and operational data
{Please TWG provide information.}
Cross-media effects
Some raw material and energy is used for the installation and operation of the
sludge-concentration equipment.
TB/EIPPCB/CAK_Draft_1 December 2011 191