# 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 29:: In order to use energy efficiently when using distillation, BAT is to use one or a combination of the techniques given below.

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

Technique
Description
Applicability
a.
Distillation optimisation
For each distillation column, the number of trays, reflux ratio, feed location and, for extractive distillations, the solvents to feed ratio are optimised
Applicability to existing units may be restricted by design, space availability and/or operational constraints
b.
Recovery of heat from column overhead gaseous stream
Reuse condensation heat from the toluene and the xylene distillation column to supply heat elsewhere in the installation
c.
Single extractive distillation column
In a conventional extractive distillation system, the separation would require a sequence of two separation steps (i.e. main distillation column with side column or stripper). In a single extractive distillation column, the separation of the solvent is carried out in a smaller distillation column that is incorporated into the column shell of the first column
Only applicable to new plants or major plant upgrades.
Applicability may be restricted for smaller capacity units as operability may be constrained by combining a number of operations into one piece of equipment
d.
Distillation column with a dividing wall
In a conventional distillation system, the separation of a three-component mixture into its pure fractions requires a direct sequence of at least two distillation columns (or main columns with side columns). With a dividing wall column, separation can be carried out in just one piece of apparatus
e.
Thermally coupled distillation
If distillation is carried out in two columns, energy flows in both columns can be coupled. The steam from the top of the first column is fed to a heat exchanger at the base of the second column
Only applicable to new plants or major plant upgrades.
Applicability depends on the set-up of the distillation columns and process conditions, e.g. working pressure

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Source: https://www.legislation.gov.uk/eudn/2017/2117/annex/division/3/division/3.4/division/BAT (the official version)
Page: https://openlegislation.uk/eu-decision-2017-2117/annex/division-3/division-3.4/division-BAT
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.