# Commission Implementing Decision (EU) 2017/2117 of 21 November 2017 establishing best available techniques (BAT) conclusions, under Directive 2010/75/EU of the European Parliament and of the Council, for the production of large volume organic chemicals (notified under document C(2017) 7469) (Text with EEA relevance), Division BAT 23:: In order to prevent or reduce the amount of sulphides discharged to waste water treatment from the spent caustic scrubber liquor originating from the removal of acid gases from the cracked gases, BAT is to use one or a combination of the techniques given below.

Extent: E+W+S+N.I.

Technique
Description
Applicability
a.
Use of low-sulphur raw materials in the cracker feed
Use of raw materials that have a low sulphur content or have been desulphurised
Applicability may be restricted by a need for sulphur doping to reduce coke build-up
b.
Maximisation of the use of amine scrubbing for the removal of acid gases
The scrubbing of the cracked gases with a regenerative (amine) solvent to remove acid gases, mainly H2S, to reduce the load on the downstream caustic scrubber
Not applicable if the lower olefin cracker is located far away from an SRU. Applicability for existing plants may be restricted by the capacity of the SRU
c.
Oxidation
Oxidation of sulphides present in the spent scrubbing liquor to sulphates, e.g. using air at elevated pressure and temperature (i.e. wet air oxidation) or an oxidising agent such as hydrogen peroxide
Generally applicable

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Source: https://www.legislation.gov.uk/eudn/2017/2117/annex/division/2/division/2.2/division/BAT+23 (the official version)
Page: https://openlegislation.uk/eu-decision-2017-2117/annex/division-2/division-2.2/division-BAT+23
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.