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Document 32017D2117
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. )
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. )
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. )
C/2017/7469
OJ L 323, 7.12.2017, p. 1–50
(BG, ES, CS, DA, DE, ET, EL, EN, FR, HR, IT, LV, LT, HU, MT, NL, PL, PT, RO, SK, SL, FI, SV)
In force
|
7.12.2017 |
EN |
Official Journal of the European Union |
L 323/1 |
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)
THE EUROPEAN COMMISSION,
Having regard to the Treaty on the Functioning of the European Union,
Having regard to Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control) (1), and in particular Article 13(5) thereof,
Whereas:
|
(1) |
Best available techniques (BAT) conclusions are the reference for setting permit conditions for installations covered by Chapter II of Directive 2010/75/EU and competent authorities should set emission limit values which ensure that, under normal operating conditions, emissions do not exceed the emission levels associated with the best available techniques as laid down in the BAT conclusions. |
|
(2) |
The forum composed of representatives of Member States, the industries concerned and non-governmental organisations promoting environmental protection, established by Commission Decision of 16 May 2011 (2), provided the Commission on 5 April 2017 with its opinion on the proposed content of the BAT reference document for the production of large volume organic chemicals. That opinion is publicly available. |
|
(3) |
The BAT conclusions set out in the Annex to this Decision are the key element of that BAT reference document. |
|
(4) |
The measures provided for in this Decision are in accordance with the opinion of the Committee established by Article 75(1) of Directive 2010/75/EU, |
HAS ADOPTED THIS DECISION:
Article 1
The best available techniques (BAT) conclusions for the production of large volume organic chemicals, as set out in the Annex, are adopted.
Article 2
This Decision is addressed to the Member States.
Done at Brussels, 21 November 2017.
For the Commission
Karmenu VELLA
Member of the Commission
(1) OJ L 334, 17.12.2010, p. 17.
(2) Commission Decision of 16 May 2011 establishing a forum for the exchange of information pursuant to Article 13 of the Directive 2010/75/EU on industrial emissions (OJ C 146, 17.5.2011, p. 3).
ANNEX
BEST AVAILABLE TECHNIQUES (BAT) CONCLUSIONS FOR THE PRODUCTION OF LARGE VOLUME ORGANIC CHEMICALS
SCOPE
These BAT conclusions concern the production of the following organic chemicals, as specified in Section 4.1 of Annex I to Directive 2010/75/EU:
|
(a) |
simple hydrocarbons (linear or cyclic, saturated or unsaturated, aliphatic or aromatic); |
|
(b) |
oxygen-containing hydrocarbons such as alcohols, aldehydes, ketones, carboxylic acids, esters and mixtures of esters, acetates, ethers, peroxides and epoxy resins; |
|
(c) |
sulphurous hydrocarbons; |
|
(d) |
nitrogenous hydrocarbons such as amines, amides, nitrous compounds, nitro compounds or nitrate compounds, nitriles, cyanates, isocyanates; |
|
(e) |
phosphorus-containing hydrocarbons; |
|
(f) |
halogenic hydrocarbons; |
|
(g) |
organometallic compounds; |
|
(k) |
surface-active agents and surfactants. |
These BAT conclusions also cover the production of hydrogen peroxide as specified in Section 4.2(e) of Annex I to Directive 2010/75/EU.
These BAT conclusions cover combustion of fuels in process furnaces/heaters, where this is part of the abovementioned activities.
These BAT conclusions cover production of the aforementioned chemicals in continuous processes where the total production capacity of those chemicals exceeds 20 kt/year.
These BAT conclusions do not address the following:
|
— |
combustion of fuels other than in a process furnace/heater or a thermal/catalytic oxidiser; this may be covered by the BAT conclusions for Large Combustion Plants (LCP); |
|
— |
incineration of waste; this may be covered by the BAT conclusions for Waste Incineration (WI); |
|
— |
ethanol production taking place on an installation covered by the activity description in Section 6.4(b)(ii) of Annex I to Directive 2010/75/EU or covered as a directly associated activity to such an installation; this may be covered by the BAT conclusions for Food, Drink and Milk Industries (FDM). |
Other BAT conclusions which are complementary for the activities covered by these BAT conclusions include:
|
— |
Common Waste Water/Waste Gas Treatment/Management Systems in the Chemical Sector (CWW); |
|
— |
Common Waste Gas Treatment in the Chemical Sector (WGC). |
Other BAT conclusions and reference documents which may be of relevance for the activities covered by these BAT conclusions are the following:
|
— |
Economics and Cross-media Effects (ECM); |
|
— |
Emissions from Storage (EFS); |
|
— |
Energy Efficiency (ENE); |
|
— |
Industrial Cooling Systems (ICS); |
|
— |
Large Combustion Plants (LCP); |
|
— |
Refining of Mineral Oil and Gas (REF); |
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— |
Monitoring of Emissions to Air and Water from IED installations (ROM); |
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— |
Waste Incineration (WI); |
|
— |
Waste Treatment (WT). |
GENERAL CONSIDERATIONS
Best Available Techniques
The techniques listed and described in these BAT conclusions are neither prescriptive nor exhaustive. Other techniques may be used that ensure at least an equivalent level of environmental protection.
Unless otherwise stated, the BAT conclusions are generally applicable.
Averaging periods and reference conditions for emissions to air
Unless stated otherwise, the emission levels associated with the best available techniques (BAT-AELs) for emissions to air given in these BAT conclusions refer to values of concentration, expressed as mass of emitted substance per volume of waste gas under standard conditions (dry gas at a temperature of 273,15 K, and a pressure of 101,3 kPa), and expressed in the unit mg/Nm3.
Unless stated otherwise, the averaging periods associated with the BAT-AELs for emissions to air are defined as follows.
|
Type of measurement |
Averaging period |
Definition |
|
Continuous |
Daily average |
Average over a period of 1 day based on valid hourly or half-hourly averages |
|
Periodic |
Average over the sampling period |
Average of three consecutive measurements of at least 30 minutes each (1) (2) |
Where BAT-AELs refer to specific emission loads, expressed as load of emitted substance per unit of production output, the average specific emission loads ls are calculated using Equation 1:
|
Equation 1: |
|
where:
|
n |
= |
number of measurement periods; |
|
ci |
= |
average concentration of the substance during ith measurement period; |
|
qi |
= |
average flow rate during ith measurement period; |
|
pi |
= |
production output during ith measurement period. |
Reference oxygen level
For process furnaces/heaters, the reference oxygen level of the waste gases (OR ) is 3 vol-%.
Conversion to reference oxygen level
The emission concentration at the reference oxygen level is calculated using Equation 2:
|
Equation 2: |
|
where:
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ER |
= |
emission concentration at the reference oxygen level OR ; |
|
OR |
= |
reference oxygen level in vol-%; |
|
EM |
= |
measured emission concentration; |
|
OM |
= |
measured oxygen level in vol-%. |
Averaging periods for emissions to water
Unless stated otherwise, the averaging periods associated with the environmental performance levels associated with the best available techniques (BAT-AEPLs) for emissions to water expressed in concentrations are defined as follows.
|
Averaging period |
Definition |
|
Average of values obtained during one month |
Flow-weighted average value from 24-hour flow-proportional composite samples obtained during 1 month under normal operating conditions (3) |
|
Average of values obtained during one year |
Flow-weighted average value from 24-hour flow-proportional composite samples obtained during 1 year under normal operating conditions (3) |
Flow-weighted average concentrations of the parameter (cw ) are calculated using Equation 3:
|
Equation 3: |
|
where:
|
n |
= |
number of measurement periods; |
|
ci |
= |
average concentration of the parameter during ith measurement period; |
|
qi |
= |
average flow rate during ith measurement period. |
Where BAT-AEPLs refer to specific emission loads, expressed as load of emitted substance per unit of production output, the average specific emission loads are calculated using Equation 1.
Acronyms and definitions
For the purposes of these BAT conclusions, the following acronyms and definitions apply.
|
Term used |
Definition |
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|
BAT-AEPL |
Environmental performance level associated with BAT, as described in Commission Implementing Decision 2012/119/EU (4). BAT-AEPLs include emission levels associated with the best available techniques (BAT-AELs) as defined in Article 3(13) of Directive 2010/75/EU |
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BTX |
Collective term for benzene, toluene and ortho-/meta-/para-xylene or mixtures thereof |
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CO |
Carbon monoxide |
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|
Combustion unit |
Any technical apparatus in which fuels are oxidised in order to use the heat thus generated. Combustion units include boilers, engines, turbines and process furnaces/heaters, but do not include waste gas treatment units (e.g. a thermal/catalytic oxidiser used for the abatement of organic compounds) |
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|
Continuous measurement |
Measurement using an ‘automated measuring system’ permanently installed on site |
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Continuous process |
A process in which the raw materials are fed continuously into the reactor with the reaction products then fed into connected downstream separation and/or recovery units |
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|
Copper |
The sum of copper and its compounds, in dissolved or particulate form, expressed as Cu |
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|
DNT |
Dinitrotoluene |
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|
EB |
Ethylbenzene |
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EDC |
Ethylene dichloride |
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|
EG |
Ethylene glycols |
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EO |
Ethylene oxide |
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Ethanolamines |
Collective term for monoethanolamine, diethanolamine and triethanolamine, or mixtures thereof |
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|
Ethylene glycols |
Collective term for monoethylene glycol, diethylene glycol and triethylene glycol, or mixtures thereof |
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|
Existing plant |
A plant that is not a new plant |
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Existing unit |
A unit that is not a new unit |
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|
Flue-gas |
The exhaust gas exiting a combustion unit |
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|
I-TEQ |
International toxic equivalent – derived by using the international toxic equivalence factors, as defined in Annex VI, part 2 to Directive 2010/75/EU |
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|
Lower olefins |
Collective term for ethylene, propylene, butylene and butadiene, or mixtures thereof |
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|
Major plant upgrade |
A major change in the design or technology of a plant with major adjustments or replacements of the process and/or abatement units and associated equipment |
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|
MDA |
Methylene diphenyl diamine |
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|
MDI |
Methylene diphenyl diisocyanate |
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MDI plant |
Plant for the production of MDI from MDA via phosgenation |
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|
New plant |
A plant first permitted on the site of the installation following the publication of these BAT conclusions or a complete replacement of a plant following the publication of these BAT conclusions |
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|
New unit |
A unit first permitted following the publication of these BAT conclusions or a complete replacement of a unit following the publication of these BAT conclusions |
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|
NOX precursors |
Nitrogen-containing compounds (e.g. ammonia, nitrous gases and nitrogen-containing organic compounds) in the input to a thermal treatment that lead to NOX emissions. Elementary nitrogen is not included |
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|
PCDD/F |
Polychlorinated dibenzo-dioxins and -furans |
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|
Periodic measurement |
Measurement at specified time intervals using manual or automated methods |
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|
Process furnace/heater |
Process furnaces or heaters are:
It should be noted that, as a consequence of the application of good energy recovery practices, some of the process furnaces/heaters may have an associated steam/electricity generation system. This is considered to be an integral design feature of the process furnace/heater that cannot be considered in isolation. |
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|
Process off-gas |
The gas leaving a process which is further treated for recovery and/or abatement |
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|
NOX |
The sum of nitrogen monoxide (NO) and nitrogen dioxide (NO2), expressed as NO2 |
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|
Residues |
Substances or objects generated by the activities covered by the scope of this document, as waste or by-products |
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|
RTO |
Regenerative thermal oxidiser |
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|
SCR |
Selective catalytic reduction |
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|
SMPO |
Styrene monomer and propylene oxide |
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|
SNCR |
Selective non-catalytic reduction |
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|
SRU |
Sulphur recovery unit |
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|
TDA |
Toluene diamine |
||||
|
TDI |
Toluene diisocyanate |
||||
|
TDI plant |
Plant for the production of TDI from TDA via phosgenation |
||||
|
TOC |
Total organic carbon, expressed as C; includes all organic compounds (in water) |
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|
Total suspended solids (TSS) |
Mass concentration of all suspended solids, measured via filtration through glass fibre filters and gravimetry |
||||
|
TVOC |
Total volatile organic carbon; total volatile organic compounds which are measured by a flame ionisation detector (FID) and expressed as total carbon |
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|
Unit |
A segment/subpart of a plant in which a specific process or operation is carried out (e.g. reactor, scrubber, distillation column). Units can be new units or existing units |
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|
Valid hourly or half-hourly average |
An hourly (or half-hourly) average is considered valid when there is no maintenance or malfunction of the automated measuring system |
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|
VCM |
Vinyl chloride monomer |
||||
|
VOCs |
Volatile organic compounds as defined in Article 3(45) of Directive 2010/75/EU |
1. GENERAL BAT CONCLUSIONS
The sector-specific BAT conclusions included in Sections 2 to 11 apply in addition to the general BAT conclusions given in this section.
1.1. Monitoring of emissions to air
|
BAT 1: |
BAT is to monitor channelled emissions to air from process furnaces/heaters in accordance with EN standards and with at least the minimum frequency given in the table below. If EN standards are not available, BAT is to use ISO, national or other international standards that ensure the provision of data of an equivalent scientific quality.
|
|
BAT 2: |
BAT is to monitor channelled emissions to air other than from process furnaces/heaters in accordance with EN standards and with at least the minimum frequency given in the table below. If EN standards are not available, BAT is to use ISO, national or other international standards that ensure the provision of data of an equivalent scientific quality.
|
1.2. Emissions to air
1.2.1. Emissions to air from process furnaces/heaters
|
BAT 3: |
In order to reduce emissions to air of CO and unburnt substances from process furnaces/heaters, BAT is to ensure an optimised combustion.
Optimised combustion is achieved by good design and operation of the equipment which includes optimisation of the temperature and residence time in the combustion zone, efficient mixing of the fuel and combustion air, and combustion control. Combustion control is based on the continuous monitoring and automated control of appropriate combustion parameters (e.g. O2, CO, fuel to air ratio, and unburnt substances). |
|
BAT 4: |
In order to reduce NOX emissions to air from process furnaces/heaters, BAT is to use one or a combination of the techniques given below.
BAT-associated emission levels (BAT-AELs): See Table 2.1 and Table 10.1. |
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BAT 5: |
In order to prevent or reduce dust emissions to air from process furnaces/heaters, BAT is to use one or a combination of the techniques given below.
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BAT 6: |
In order to prevent or reduce SO2 emissions to air from process furnaces/heaters, BAT is to use one or both of the techniques given below.
|
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1.2.2. Emissions to air from the use of SCR or SNCR
|
BAT 7: |
In order to reduce emissions to air of ammonia which is used in selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) for the abatement of NOX emissions, BAT is to optimise the design and/or operation of SCR or SNCR (e.g. optimised reagent to NOX ratio, homogeneous reagent distribution and optimum size of the reagent drops).
BAT-associated emission levels (BAT-AELs) for emissions from a lower olefins cracker furnace when SCR or SNCR is used: Table 2.1. |
1.2.3. Emissions to air from other processes/sources
1.2.3.1.
|
BAT 8: |
In order to reduce the load of pollutants sent to the final waste gas treatment, and to increase resource efficiency, BAT is to use an appropriate combination of the techniques given below for process off-gas streams.
|
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BAT 9: |
In order to reduce the load of pollutants sent to the final waste gas treatment, and to increase energy efficiency, BAT is to send process off-gas streams with a sufficient calorific value to a combustion unit. BAT 8a and 8b have priority over sending process off-gas streams to a combustion unit.
Applicability: Sending process off-gas streams to a combustion unit may be restricted due to the presence of contaminants or due to safety considerations. |
|
BAT 10: |
In order to reduce channelled emissions of organic compounds to air, BAT is to use one or a combination of the techniques given below.
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BAT 11: |
In order to reduce channelled dust emissions to air, BAT is to use one or a combination of the techniques given below.
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BAT 12: |
In order to reduce emissions to air of sulphur dioxide and other acid gases (e.g. HCl), BAT is to use wet scrubbing.
Description: For the description of wet scrubbing, see Section 12.1 |
1.2.3.2.
|
BAT 13: |
In order to reduce emissions to air of NOX, CO, and SO2 from a thermal oxidiser, BAT is to use an appropriate combination of the techniques given below.
|
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1.3. Emissions to water
|
BAT 14: |
In order to reduce the waste water volume, the pollutant loads discharged to a suitable final treatment (typically biological treatment), and emissions to water, BAT is to use an integrated waste water management and treatment strategy that includes an appropriate combination of process-integrated techniques, techniques to recover pollutants at source, and pretreatment techniques, based on the information provided by the inventory of waste water streams specified in the CWW BAT conclusions. |
1.4. Resource efficiency
|
BAT 15: |
In order to increase resource efficiency when using catalysts, BAT is to use a combination of the techniques given below.
|
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BAT 16: |
In order to increase resource efficiency, BAT is to recover and reuse organic solvents.
Description: Organic solvents used in processes (e.g. chemical reactions) or operations (e.g. extraction) are recovered using appropriate techniques (e.g. distillation or liquid phase separation), purified if necessary (e.g. using distillation, adsorption, stripping or filtration) and returned to the process or operation. The amount recovered and reused is process-specific. |
1.5. Residues
|
BAT 17: |
In order to prevent or, where that is not practicable, to reduce the amount of waste being sent for disposal, BAT is to use an appropriate combination of the techniques given below.
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1.6. Other than normal operating conditions
|
BAT 18: |
In order to prevent or reduce emissions from equipment malfunctions, BAT is to use all of the techniques given below.
|
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BAT 19: |
In order to prevent or reduce emissions to air and water occurring during other than normal operating conditions, BAT is to implement measures commensurate with the relevance of potential pollutant releases for:
|
2. BAT CONCLUSIONS FOR LOWER OLEFINS PRODUCTION
The BAT conclusions in this section apply to the production of lower olefins using the steam cracking process, and apply in addition to the general BAT conclusions given in Section 1.
2.1. Emissions to air
2.1.1. BAT-AELs for emissions to air from a lower olefins cracker furnace
Table 2.1
BAT-AELs for emissions to air of NOX and NH3 from a lower olefins cracker furnace
|
Parameter |
(daily average or average over the sampling period) (mg/Nm3, at 3 vol-% O2) |
|
|
New furnace |
Existing furnace |
|
|
NOX |
60–100 |
70–200 |
|
NH3 |
< 5–15 (21) |
|
The associated monitoring is in BAT 1.
2.1.2. Techniques to reduce emissions from decoking
|
BAT 20: |
In order to reduce emissions to air of dust and CO from the decoking of the cracker tubes, BAT is to use an appropriate combination of the techniques to reduce the frequency of decoking given below and one or a combination of the abatement techniques given below.
|
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2.2. Emissions to water
|
BAT 21: |
In order to prevent or reduce the amount of organic compounds and waste water discharged to waste water treatment, BAT is to maximise the recovery of hydrocarbons from the quench water of the primary fractionation stage and reuse the quench water in the dilution steam generation system.
Description: The technique consists of ensuring an effective separation of organic and aqueous phases. The recovered hydrocarbons are recycled to the cracker or used as raw materials in other chemical processes. Organic recovery can be enhanced, e.g. through the use of steam or gas stripping, or the use of a reboiler. Treated quench water is reused within the dilution steam generation system. A quench water purge stream is discharged to downstream final waste water treatment to prevent the build-up of salts in the system. |
|
BAT 22: |
In order to reduce the organic load discharged to waste water treatment from the spent caustic scrubber liquor originating from the removal of H2S from the cracked gases, BAT is to use stripping.
Description: For the description of stripping see Section 12.2. The stripping of scrubber liquors is carried out using a gaseous stream, which is then combusted (e.g. in the cracker furnace). |
|
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.
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3. BAT CONCLUSIONS FOR AROMATICS PRODUCTION
The BAT conclusions in this section apply to the production of benzene, toluene, ortho-, meta- and para-xylene (commonly known as BTX aromatics) and cyclohexane from the pygas by-product of steam crackers and from reformate/naphtha produced in catalytic reformers; and apply in addition to the general BAT conclusions given in Section 1.
3.1. Emissions to air
|
BAT 24: |
In order to reduce the organic load from process off-gases sent to the final waste gas treatment and to increase resource efficiency, BAT is to recover organic materials by using BAT 8b. or, where that is not practicable, to recover energy from these process off-gases (see also BAT 9). |
|
BAT 25: |
In order to reduce emissions to air of dust and organic compounds from the regeneration of hydrogenation catalyst, BAT is to send the process off-gas from catalyst regeneration to a suitable treatment system.
Description: The process off-gas is sent to wet or dry dust abatement devices to remove dust and then to a combustion unit or a thermal oxidiser to remove organic compounds in order to avoid direct emissions to air or flaring. The use of decoking drums alone is not sufficient. |
3.2. Emissions to water
|
BAT 26: |
In order to reduce the amount of organic compounds and waste water discharged from aromatic extraction units to waste water treatment, BAT is either to use dry solvents or to use a closed system for the recovery and reuse of water when wet solvents are used. |
|
BAT 27: |
In order to reduce the waste water volume and the organic load discharged to waste water treatment, BAT is to use an appropriate combination of the techniques given below.
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3.3. Resource efficiency
|
BAT 28: |
In order to use resources efficiently, BAT is to maximise the use of co-produced hydrogen, e.g. from dealkylation reactions, as a chemical reagent or fuel by using BAT 8a. or, where that is not practicable, to recover energy from these process vents (see BAT 9). |
3.4. Energy efficiency
|
BAT 29: |
In order to use energy efficiently when using distillation, BAT is to use one or a combination of the techniques given below.
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3.5. Residues
|
BAT 30: |
In order to prevent or reduce the amount of spent clay being sent for disposal, BAT is to use one or both of the techniques given below.
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4. BAT CONCLUSIONS FOR ETHYLBENZENE AND STYRENE MONOMER PRODUCTION
The BAT conclusions in this section apply to the production of ethlybenzene using either the zeolite or AlCl3 catalysed alkylation process; and the production of styrene monomer either by ethylbenzene dehydrogenation or co-production with propylene oxide; and apply in addition to the general BAT conclusions given in Section 1.
4.1. Process selection
|
BAT 31: |
In order to prevent or reduce emissions to air of organic compounds and acid gases, the generation of waste water and the amount of waste being sent for disposal from the alkylation of benzene with ethylene, BAT for new plants and major plant upgrades is to use the zeolite catalyst process. |
4.2. Emissions to air
|
BAT 32: |
In order to reduce the load of HCl sent to the final waste gas treatment from the alkylation unit in the AlCl3-catalysed ethylbenzene production process, BAT is to use caustic scrubbing.
Description: For the description of caustic scrubbing, see Section 12.1. Applicability: Only applicable to existing plants using the AlCl3 catalysed ethylbenzene production process. |
|
BAT 33: |
In order to reduce the load of dust and HCl sent to the final waste gas treatment from catalyst replacement operations in the AlCl3-catalysed ethylbenzene production process, BAT is to use wet scrubbing and then use the spent scrubbing liquor as wash water in the post-alkylation reactor wash section.
Description: For the description of wet scrubbing, see Section 12.1. |
|
BAT 34: |
In order to reduce the organic load sent to the final waste gas treatment from the oxidation unit in the SMPO production process, BAT is to use one or a combination of the techniques given below.
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BAT 35: |
In order to reduce emissions of organic compounds to air from the acetophenone hydrogenation unit in the SMPO production process, during other than normal operating conditions (such as start-up events), BAT is to send the process off-gas to a suitable treatment system. |
4.3. Emissions to water
|
BAT 36: |
In order to reduce waste water generation from ethylbenzene dehydrogenation and to maximise the recovery of organic compounds, BAT is to use an appropriate combination of the techniques given below.
|
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BAT 37: |
In order to reduce emissions to water of organic peroxides from the oxidation unit in the SMPO production process and to protect the downstream biological waste water treatment plant, BAT is to pretreat waste water containing organic peroxides using hydrolysis before it is combined with other waste water streams and discharged to the final biological treatment.
Description: For the description of hydrolysis see Section 12.2. |
4.4. Resource efficiency
|
BAT 38: |
In order to recover organic compounds from ethylbenzene dehydrogenation prior to the recovery of hydrogen (see BAT 39), BAT is to use one or both of the techniques given below.
|
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|
BAT 39: |
In order to increase resource efficiency, BAT is to recover the co-produced hydrogen from ethylbenzene dehydrogenation, and to use it either as a chemical reagent or to combust the dehydrogenation off-gas as a fuel (e.g. in the steam superheater). |
|
BAT 40: |
In order to increase the resource efficiency of the acetophenone hydrogenation unit in the SMPO production process, BAT is to minimise excess hydrogen or to recycle hydrogen by using BAT 8a. If BAT 8a is not applicable, BAT is to recover energy (see BAT 9). |
4.5. Residues
|
BAT 41: |
In order to reduce the amount of waste being sent for disposal from spent catalyst neutralisation in the AlCl3-catalysed ethylbenzene production process, BAT is to recover residual organic compounds by stripping and then concentrate the aqueous phase to give a usable AlCl3 by-product.
Description: Steam stripping is first used to remove VOCs, then the spent catalyst solution is concentrated by evaporation to give a usable AlCl3 by-product. The vapour phase is condensed to give a HCl solution that is recycled into the process. |
|
BAT 42: |
In order to prevent or reduce the amount of waste tar being sent for disposal from the distillation unit of ethylbenzene production, BAT is to use one or a combination of the techniques given below.
|
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|
BAT 43: |
In order to reduce the generation of coke (which is both a catalyst poison and a waste) from units producing styrene by ethylbenzene dehydrogenation, BAT is to operate at the lowest possible pressure that is safe and practicable. |
|
BAT 44: |
In order to reduce the amount of organic residues being sent for disposal from styrene monomer production including its co-production with propylene oxide, BAT is to use one or a combination of the techniques given below.
|
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5. BAT CONCLUSIONS FOR FORMALDEHYDE PRODUCTION
The BAT conclusions in this section apply in addition to the general BAT conclusions given in Section 1.
5.1. Emissions to air
|
BAT 45: |
In order to reduce emissions of organic compounds to air from formaldehyde production and to use energy efficiently, BAT is to use one of the techniques given below.
Table 5.1 BAT-AELs for emissions of TVOC and formaldehyde to air from formaldehyde production
The associated monitoring is in BAT 2. |
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5.2. Emissions to water
|
BAT 46: |
In order to prevent or reduce waste water generation (e.g. from cleaning, spills and condensates) and the organic load discharged to further waste water treatment, BAT is to use one or both of the techniques given below.
|
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5.3. Residues
|
BAT 47: |
In order to reduce the amount of paraformaldehyde-containing waste being sent for disposal, BAT is to use one or a combination of the techniques given below.
|
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6. BAT CONCLUSIONS FOR ETHYLENE OXIDE AND ETHYLENE GLYCOLS PRODUCTION
The BAT conclusions in this section apply in addition to the general BAT conclusions given in Section 1.
6.1. Process selection
|
BAT 48: |
In order to reduce the consumption of ethylene and emissions to air of organic compounds and CO2, BAT for new plants and major plant upgrades is to use oxygen instead of air for the direct oxidation of ethylene to ethylene oxide. |
6.2. Emissions to air
|
BAT 49: |
In order to recover ethylene and energy and to reduce emissions of organic compounds to air from the EO plant, BAT is to use both of the techniques given below.
|
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|
BAT 50: |
In order to reduce the consumption of ethylene and oxygen and to reduce CO2 emissions to air from the EO unit, BAT is to use a combination of the techniques in BAT 15 and to use inhibitors.
Description: The addition of small amounts of an organochlorine inhibitor (such as ethylchloride or dichloroethane) to the reactor feed in order to reduce the proportion of ethylene that is fully oxidised to carbon dioxide. Suitable parameters for the monitoring of catalyst performance include the heat of reaction and the CO2 formation per tonne of ethylene feed. |
|
BAT 51: |
In order to reduce emissions of organic compounds to air from the desorption of CO2 from the scrubbing medium used in the EO plant, BAT is to use a combination of the techniques given below.
Table 6.1 BAT-AEL for emissions of organic compounds to air from the desorption of CO2 from the scrubbing medium used in the EO plant
The associated monitoring is in BAT 2. |
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|
BAT 52: |
In order to reduce EO emissions to air, BAT is to use wet scrubbing for waste gas streams containing EO.
Description: For the description of wet scrubbing, see Section 12.1. Scrubbing with water to remove EO from waste gas streams before direct release or before further abatement of organic compounds. |
|
BAT 53: |
In order to prevent or reduce emissions of organic compounds to air from cooling of the EO absorbent in the EO recovery unit, BAT is to use one of the techniques given below.
|
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6.3. Emissions to water
|
BAT 54: |
In order to reduce the waste water volume and to reduce the organic load discharged from the product purification to final waste water treatment, BAT is to use one or both of the techniques given below.
|
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6.4. Residues
|
BAT 55: |
In order to reduce the amount of organic waste being sent for disposal from the EO and EG plant, BAT is to use a combination of the techniques given below.
|
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7. BAT CONCLUSIONS FOR PHENOL PRODUCTION
The BAT conclusions in this section apply to the production of phenol from cumene, and apply in addition to the general BAT conclusions given in Section 1.
7.1. Emissions to air
|
BAT 56: |
In order to recover raw materials and to reduce the organic load sent from the cumene oxidation unit to the final waste gas treatment, BAT is to use a combination of the techniques given below.
|
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|
BAT 57: |
In order to reduce emissions of organic compounds to air, BAT is to use technique d given below for waste gas from the cumene oxidation unit. For any other individual or combined waste gas streams, BAT is to use one or a combination of the techniques given below.
Table 7.1 BAT-AELs for emissions of TVOC and benzene to air from the production of phenol
The associated monitoring is in BAT 2. |
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7.2. Emissions to water
|
BAT 58: |
In order to reduce emissions to water of organic peroxides from the oxidation unit and, if necessary, to protect the downstream biological waste water treatment plant, BAT is to pretreat waste water containing organic peroxides using hydrolysis before it is combined with other waste water streams and discharged to the final biological treatment.
Description: For the description of hydrolysis, see Section 12.2. Waste water (mainly from the condensers and the adsorber regeneration, after phase separation) is treated thermally (at temperatures above 100 °C and a high pH) or catalytically to decompose organic peroxides to non-ecotoxic and more readily biodegradable compounds. Table 7.2 BAT-AEPL for organic peroxides at the outlet of the peroxides decomposition unit
|
|
BAT 59: |
In order to reduce the organic load discharged from the cleavage unit and the distillation unit to further waste water treatment, BAT is to recover phenol and other organic compounds (e.g. acetone) using extraction followed by stripping.
Description: Recovery of phenol from phenol-containing waste water streams by adjustment of the pH to < 7, followed by extraction with a suitable solvent and stripping of the waste water to remove residual solvent and other low-boiling compounds (e.g. acetone). For the description of the treatment techniques, see Section 12.2. |
7.3. Residues
|
BAT 60: |
In order to prevent or reduce the amount of tar being sent for disposal from phenol purification, BAT is to use one or both of the techniques given below.
|
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8. BAT CONCLUSIONS FOR ETHANOLAMINES PRODUCTION
The BAT conclusions in this section apply in addition to the general BAT conclusions given in Section 1.
8.1. Emissions to air
|
BAT 61: |
In order to reduce ammonia emissions to air and to reduce the consumption of ammonia from the aqueous ethanolamines production process, BAT is to use a multistage wet scrubbing system.
Description: For the description of wet scrubbing, see Section 12.1. Unreacted ammonia is recovered from the off-gas of the ammonia stripper and also from the evaporation unit by wet scrubbing in at least two stages followed by ammonia recycling into the process. |
8.2. Emissions to water
|
BAT 62: |
In order to prevent or reduce emissions of organic compounds to air and emissions to water of organic substances from the vacuum systems, BAT is to use one or a combination of the techniques given below.
|
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8.3. Raw material consumption
|
BAT 63: |
In order to use ethylene oxide efficiently, BAT is to use a combination of the techniques given below.
|
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9. BAT CONCLUSIONS FOR TOLUENE DIISOCYANATE (TDI) AND METHYLENE DIPHENYL DIISOCYANATE (MDI) PRODUCTION
The BAT conclusions in this section cover the production of:
|
— |
dinitrotoluene (DNT) from toluene; |
|
— |
toluene diamine (TDA) from DNT; |
|
— |
TDI from TDA; |
|
— |
methylene diphenyl diamine (MDA) from aniline; |
|
— |
MDI from MDA; |
and apply in addition to the general BAT conclusions given in Section 1.
9.1. Emissions to air
|
BAT 64: |
In order to reduce the load of organic compounds, NOX, NOX precursors and SOX sent to the final waste gas treatment (see BAT 66) from DNT, TDA and MDA plants, BAT is to use a combination of the techniques given below.
|
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|
BAT 65: |
In order to reduce the load of HCl and phosgene sent to the final waste gas treatment and to increase resource efficiency, BAT is to recover HCl and phosgene from the process off-gas streams of TDI and/or MDI plants by using an appropriate combination of the techniques given below.
|
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|
BAT 66: |
In order to reduce emissions to air of organic compounds (including chlorinated hydrocarbons), HCl and chlorine, BAT is to treat combined waste gas streams using a thermal oxidiser followed by caustic scrubbing.
Description: The individual waste gas streams from DNT, TDA, TDI, MDA and MDI plants are combined to one or several waste gas streams for treatment. (See Section 12.1 for the descriptions of thermal oxidiser and scrubbing.) Instead of a thermal oxidiser, an incinerator may be used for the combined treatment of liquid waste and the waste gas. Caustic scrubbing is wet scrubbing with caustic added to improve the HCl and chlorine removal efficiency. Table 9.1 BAT-AELs for emissions of TVOC, tetrachloromethane, Cl2, HCl and PCDD/F to air from the TDI/MDI process
The associated monitoring is in BAT 2. |
|
BAT 67: |
In order to reduce emissions to air of PCDD/F from a thermal oxidiser (see Section 12.1) treating process off-gas streams containing chlorine and/or chlorinated compounds, BAT is to use technique a, if necessary followed by technique b, given below.
BAT-associated emission levels (BAT-AELs): See Table 9.1. |
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9.2. Emissions to water
|
BAT 68: |
BAT is to monitor emissions to water with at least the frequency given below and in accordance with EN standards. If EN standards are not available, BAT is to use ISO, national or other international standards that ensure the provision of data of an equivalent scientific quality.
|
|
BAT 69: |
In order to reduce the load of nitrite, nitrate and organic compounds discharged from the DNT plant to waste water treatment, BAT is to recover raw materials, to reduce the waste water volume and to reuse water by using an appropriate combination of the techniques given below.
BAT-associated waste water volume: See Table 9.2. |
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|
BAT 70: |
In order to reduce the load of poorly biodegradable organic compounds discharged from the DNT plant to further waste water treatment, BAT is to pretreat the waste water using one or both of the techniques given below.
Table 9.2 BAT-AEPLs for discharge from the DNT plant at the outlet of the pretreatment unit to further waste water treatment
The associated monitoring for TOC is in BAT 68. |
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|
BAT 71: |
In order to reduce waste water generation and the organic load discharged from the TDA plant to waste water treatment, BAT is to use a combination of techniques a., b. and c. and then to use technique d. as given below.
Table 9.3 BAT-AEPL for discharge from the TDA plant to waste water treatment
|
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|
BAT 72: |
In order to prevent or reduce the organic load discharged from MDI and/or TDI plants to final waste water treatment, BAT is to recover solvents and reuse water by optimising the design and operation of the plant.
Table 9.4 BAT-AEPL for discharge to waste water treatment from a TDI or MDI plant
The associated monitoring is in BAT 68. |
|
BAT 73: |
In order to reduce the organic load discharged from a MDA plant to further waste water treatment, BAT is to recover organic material using one or a combination of the techniques given below.
|
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9.3. Residues
|
BAT 74: |
In order to reduce the amount of organic residues being sent for disposal from the TDI plant, BAT is to use a combination of the techniques given below.
|
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10. BAT CONCLUSIONS FOR ETHYLENE DICHLORIDE AND VINYL CHLORIDE MONOMER PRODUCTION
The BAT conclusions in this section apply in addition to the general BAT conclusions given in Section 1.
10.1. Emissions to air
10.1.1. BAT-AEL for emissions to air from an EDC cracker furnace
Table 10.1
BAT-AELs for emissions to air of NOX from an EDC cracker furnace
|
Parameter |
(daily average or average over the sampling period) (mg/Nm3, at 3 vol-% O2) |
|
NOx |
50–100 |
The associated monitoring is in BAT 1.
10.1.2. Techniques and BAT-AEL for emissions to air from other sources
|
BAT 75: |
In order to reduce the organic load sent to the final waste gas treatment and to reduce raw material consumption, BAT is to use all of the techniques given below.
|
|||||||||||||||||||||||||
|
BAT 76: |
In order to reduce emissions to air of organic compounds (including halogenated compounds), HCl and Cl2, BAT is to treat the combined waste gas streams from EDC and/or VCM production by using a thermal oxidiser followed by two-stage wet scrubbing.
Description: For the description of thermal oxidiser, wet and caustic scrubbing, see Section 12.1. Thermal oxidation can be carried out in a liquid waste incineration plant. In this case, the oxidation temperature exceeds 1 100 °C with a minimum residence time of 2 seconds, with subsequent rapid cooling of exhaust gases to prevent the de novo synthesis of PCDD/F. Scrubbing is carried out in two stages: Wet scrubbing with water and, typically, recovery of hydrochloric acid, followed by wet scrubbing with caustic. Table 10.2 BAT-AELs for emissions of TVOC, the sum of EDC and VCM, Cl2, HCl and PCDD/F to air from the production of EDC/VCM
The associated monitoring is in BAT 2. |
|
BAT 77: |
In order to reduce emissions to air of PCDD/F from a thermal oxidiser (see Section 12.1) treating process off-gas streams containing chlorine and/or chlorinated compounds, BAT is to use technique a, if necessary followed by technique b, given below.
BAT-associated emission levels (BAT-AELs): See Table 10.2. |
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|
BAT 78: |
In order to reduce emissions to air of dust and CO from the decoking of the cracker tubes, BAT is to use one of the techniques to reduce the frequency of decoking given below and one or a combination of the abatement techniques given below.
|
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10.2. Emissions to water
|
BAT 79: |
BAT is to monitor emissions to water with at least the frequency given below and in accordance with EN standards. If EN standards are not available, BAT is to use ISO, national or other international standards that ensure the provision of data of an equivalent scientific quality.
|
|
BAT 80: |
In order to reduce the load of chlorinated compounds discharged to further waste water treatment and to reduce emissions to air from the waste water collection and treatment system, BAT is to use hydrolysis and stripping as close as possible to the source.
Description: For the description of hydrolysis and stripping, see Section 12.2. Hydrolysis is carried out at alkaline pH to decompose chloral hydrate from the oxychlorination process. This results in the formation of chloroform which is then removed by stripping, together with EDC and VCM. BAT-associated environmental performance levels (BAT-AEPLs): See Table 10.3. BAT-associated emission levels (BAT-AELs) for direct emissions to a receiving water body at the outlet of the final treatment: See Table 10.5. Table 10.3 BAT-AEPLs for chlorinated hydrocarbons in waste water at the outlet of a waste water stripper
The associated monitoring is in BAT 79. |
|
BAT 81: |
In order to reduce emissions to water of PCDD/F and copper from the oxychlorination process, BAT is to use technique a. or, alternatively, technique b together with an appropriate combination of techniques c., d. and e. given below.
Table 10.4 BAT-AEPLs for emissions to water from EDC production via oxychlorination at the outlet of the pretreatment for solids removal at plants using the fluidised-bed design
The associated monitoring is in BAT 79. Table 10.5 BAT-AELs for direct emissions of copper, EDC and PCDD/F to a receiving water body from EDC production
The associated monitoring is in BAT 79. |
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10.3. Energy efficiency
|
BAT 82: |
In order to use energy efficiently, BAT is to use a boiling reactor for the direct chlorination of ethylene.
Description: The reaction in the boiling reactor system for the direct chlorination of ethylene is typically carried out at a temperature between below 85 °C and 200 °C. In contrast to the low-temperature process, it allows for the effective recovery and reuse of the heat of reaction (e.g. for the distillation of EDC). Applicability: Only applicable to new direct chlorination plants. |
|
BAT 83: |
In order to reduce the energy consumption of EDC cracker furnaces, BAT is to use promoters for the chemical conversion.
Description: Promoters, such as chlorine or other radical-generating species, are used to enhance the cracking reaction and reduce the reaction temperature and therefore the required heat input. Promoters may be generated by the process itself or added. |
10.4. Residues
|
BAT 84: |
In order to reduce the amount of coke being sent for disposal from VCM plants, BAT is to use a combination of the techniques given below.
|
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|
BAT 85: |
In order to reduce the amount of hazardous waste being sent for disposal and to increase resource efficiency, BAT is to use all of the techniques given below.
|
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11. BAT CONCLUSIONS FOR HYDROGEN PEROXIDE PRODUCTION
The BAT conclusions in this section apply in addition to the general BAT conclusions given in Section 1.
11.1. Emissions to air
|
BAT 86: |
In order to recover solvents and to reduce emissions of organic compounds to air from all units other than the hydrogenation unit, BAT is to use an appropriate combination of the techniques given below. In the case of using air in the oxidation unit, this includes at least technique d. In the case of using pure oxygen in the oxidation unit, this includes at least technique b. using chilled water.
Table 11.1 BAT-AELs for emissions of TVOC to air from the oxidation unit
The associated monitoring is in BAT 2. |
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|
BAT 87: |
In order to reduce emissions of organic compounds to air from the hydrogenation unit during start-up operations, BAT is to use condensation and/or adsorption.
Description: For the description of condensation and adsorption, see Section 12.1. |
|
BAT 88: |
In order to prevent benzene emissions to air and water, BAT is not to use benzene in the working solution. |
11.2. Emissions to water
|
BAT 89: |
In order to reduce the waste water volume and the organic load discharged to waste water treatment, BAT is to use both of the techniques given below.
|
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|
BAT 90: |
In order to prevent or reduce emissions to water of poorly bioeliminable organic compounds, BAT is to use one of the techniques given below.
Applicability: Only applicable to waste water streams carrying the main organic load from the hydrogen peroxide plant and when the reduction of the TOC load from the hydrogen peroxide plant by means of biological treatment is lower than 90 %. |
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12. DESCRIPTIONS OF TECHNIQUES
12.1. Process off-gas and waste gas treatment techniques
|
Technique |
Description |
|
Adsorption |
A technique for removing compounds from a process off-gas or waste gas stream by retention on a solid surface (typically activated carbon). Adsorption may be regenerative or non-regenerative (see below). |
|
Adsorption (non-regenerative) |
In non-regenerative adsorption, the spent adsorbent is not regenerated but disposed of. |
|
Adsorption (regenerative) |
Adsorption where the adsorbate is subsequently desorbed, e.g. with steam (often on site) for reuse or disposal and the adsorbent is reused. For continuous operation, typically more than two adsorbers are operated in parallel, one of them in desorption mode. |
|
Catalytic oxidiser |
Abatement equipment which oxidises combustible compounds in a process off-gas or waste gas stream with air or oxygen in a catalyst bed. The catalyst enables oxidation at lower temperatures and in smaller equipment compared to a thermal oxidiser. |
|
Catalytic reduction |
NOx is reduced in the presence of a catalyst and a reducing gas. In contrast to SCR, no ammonia and/or urea are added. |
|
Caustic scrubbing |
The removal of acidic pollutants from a gas stream by scrubbing using an alkaline solution. |
|
Ceramic/metal filter |
Ceramic filter material. In circumstances where acidic compounds such as HCl, NOX, SOX and dioxins are to be removed, the filter material is fitted with catalysts and the injection of reagents may be necessary. In metal filters, surface filtration is carried out by sintered porous metal filter elements. |
|
Condensation |
A technique for removing the vapours of organic and inorganic compounds from a process off-gas or waste gas stream by reducing its temperature below its dew point so that the vapours liquefy. Depending on the operating temperature range required, there are different methods of condensation, e.g. cooling water, chilled water (temperature typically around 5 °C) or refrigerants such as ammonia or propene. |
|
Cyclone (dry or wet) |
Equipment for removal of dust from a process off-gas or waste gas stream based on imparting centrifugal forces, usually within a conical chamber. |
|
Electrostatic precipitator (dry or wet) |
A particulate control device that uses electrical forces to move particles entrained within a process off-gas or waste gas stream onto collector plates. The entrained particles are given an electrical charge when they pass through a corona where gaseous ions flow. Electrodes in the centre of the flow lane are maintained at a high voltage and generate the electrical field that forces the particles to the collector walls. |
|
Fabric filter |
Porous woven or felted fabric through which gases flow to remove particles by use of a sieve or other mechanisms. Fabric filters can be in the form of sheets, cartridges or bags with a number of the individual fabric filter units housed together in a group. |
|
Membrane separation |
Waste gas is compressed and passed through a membrane which relies on the selective permeability of organic vapours. The enriched permeate can be recovered by methods such as condensation or adsorption, or can be abated, e.g. by catalytic oxidation. The process is most appropriate for higher vapour concentrations. Additional treatment is, in most cases, needed to achieve concentration levels low enough to discharge. |
|
Mist filter |
Commonly mesh pad filters (e.g. mist eliminators, demisters) which usually consist of woven or knitted metallic or synthetic monofilament material in either a random or specific configuration. A mist filter is operated as deep-bed filtration, which takes place over the entire depth of the filter. Solid dust particles remain in the filter until it is saturated and requires cleaning by flushing. When the mist filter is used to collect droplets and/or aerosols, they clean the filter as they drain out as a liquid. It works by mechanical impingement and is velocity-dependent. Baffle angle separators are also commonly used as mist filters. |
|
Regenerative thermal oxidiser (RTO) |
Specific type of thermal oxidiser (see below) where the incoming waste gas stream is heated by a ceramic-packed bed by passing through it before entering the combustion chamber. The purified hot gases exit this chamber by passing through one (or more) ceramic-packed bed(s) (cooled by an incoming waste gas stream in an earlier combustion cycle). This reheated packed bed then begins a new combustion cycle by preheating a new incoming waste gas stream. The typical combustion temperature is 800–1 000 °C. |
|
Scrubbing |
Scrubbing or absorption is the removal of pollutants from a gas stream by contact with a liquid solvent, often water (see ‘Wet scrubbing’). It may involve a chemical reaction (see ‘Caustic scrubbing’). In some cases, the compounds may be recovered from the solvent. |
|
Selective catalytic reduction (SCR) |
The reduction of NOX to nitrogen in a catalytic bed by reaction with ammonia (usually supplied as an aqueous solution) at an optimum operating temperature of around 300–450 °C. One or more layers of catalyst may be applied. |
|
Selective non-catalytic reduction (SNCR) |
The reduction of NOX to nitrogen by reaction with ammonia or urea at a high temperature. The operating temperature window must be maintained between 900 °C and 1 050 °C. |
|
Techniques to reduce solids and/or liquids entrainment |
Techniques that reduce the carry-over of droplets or particles in gaseous streams (e.g. from chemical processes, condensers, distillation columns) by mechanical devices such as settling chambers, mist filters, cyclones and knock-out drums. |
|
Thermal oxidiser |
Abatement equipment which oxidises the combustible compounds in a process off-gas or waste gas stream by heating it with air or oxygen to above its auto-ignition point in a combustion chamber and maintaining it at a high temperature long enough to complete its combustion to carbon dioxide and water. |
|
Thermal reduction |
NOX is reduced at elevated temperatures in the presence of a reducing gas in an additional combustion chamber, where an oxidation process takes place but under low oxygen conditions/deficit of oxygen. In contrast to SNCR, no ammonia and/or urea are added. |
|
Two-stage dust filter |
A device for filtering on a metal gauze. A filter cake builds up in the first filtration stage and the actual filtration takes place in the second stage. Depending on the pressure drop across the filter, the system switches between the two stages. A mechanism to remove the filtered dust is integrated into the system. |
|
Wet scrubbing |
See ‘Scrubbing’ above. Scrubbing where the solvent used is water or an aqueous solution, e.g. caustic scrubbing for abating HCl. See also ‘Wet dust scrubbing’. |
|
Wet dust scrubbing |
See ‘Wet scrubbing’ above. Wet dust scrubbing entails separating the dust by intensively mixing the incoming gas with water, mostly combined with the removal of the coarse particles by the use of centrifugal force. In order to achieve this, the gas is released inside tangentially. The removed solid dust is collected at the bottom of the dust scrubber. |
12.2. Waste water treatment techniques
All of the techniques listed below can also be used to purify water streams in order to enable reuse/recycling of water. Most of them are also used to recover organic compounds from process water streams.
|
Technique |
Description |
|
Adsorption |
Separation method in which compounds (i.e. pollutants) in a fluid (i.e. waste water) are retained on a solid surface (typically activated carbon). |
|
Chemical oxidation |
Organic compounds are oxidised with ozone or hydrogen peroxide, optionally supported by catalysts or UV radiation, to convert them into less harmful and more easily biodegradable compounds |
|
Coagulation and flocculation |
Coagulation and flocculation are used to separate suspended solids from waste water and are often carried out in successive steps. Coagulation is carried out by adding coagulants with charges opposite to those of the suspended solids. Flocculation is carried out by adding polymers, so that collisions of microfloc particles cause them to bond to produce larger flocs. |
|
Distillation |
Distillation is a technique to separate compounds with different boiling points by partial evaporation and recondensation. Waste water distillation is the removal of low-boiling contaminants from waste water by transferring them into the vapour phase. Distillation is carried out in columns, equipped with plates or packing material, and a downstream condenser. |
|
Extraction |
Dissolved pollutants are transferred from the waste water phase to an organic solvent, e.g. in counter-current columns or mixer-settler systems. After phase separation, the solvent is purified, e.g. by distillation, and returned to the extraction. The extract containing the pollutants is disposed of or returned to the process. Losses of solvent to the waste water are controlled downstream by appropriate further treatment (e.g. stripping). |
|
Evaporation |
The use of distillation (see above) to concentrate aqueous solutions of high-boiling substances for further use, processing or disposal (e.g. waste water incineration) by transferring water to the vapour phase. Typically carried out in multistage units with increasing vacuum, to reduce the energy demand. The water vapours are condensed, to be reused or discharged as waste water. |
|
Filtration |
The separation of solids from a waste water carrier by passing it through a porous medium. It includes different types of techniques, e.g. sand filtration, microfiltration and ultrafiltration. |
|
Flotation |
A process in which solid or liquid particles are separated from the waste water phase by attaching to fine gas bubbles, usually air. The buoyant particles accumulate at the water surface and are collected with skimmers. |
|
Hydrolysis |
A chemical reaction in which organic or inorganic compounds react with water, typically in order to convert non-biodegradable to biodegradable or toxic to non-toxic compounds. To enable or enhance the reaction, hydrolysis is carried out at an elevated temperature and possibly pressure (thermolysis) or with the addition of strong alkalis or acids or using a catalyst. |
|
Precipitation |
The conversion of dissolved pollutants (e.g. metal ions) into insoluble compounds by reaction with added precipitants. The solid precipitates formed are subsequently separated by sedimentation, flotation or filtration. |
|
Sedimentation |
Separation of suspended particles and suspended material by gravitational settling. |
|
Stripping |
Volatile compounds are removed from the aqueous phase by a gaseous phase (e.g. steam, nitrogen or air) that is passed through the liquid, and are subsequently recovered (e.g. by condensation) for further use or disposal. The removal efficiency may be enhanced by increasing the temperature or reducing the pressure. |
|
Waste water incineration |
The oxidation of organic and inorganic pollutants with air and simultaneous evaporation of water at normal pressure and temperatures between 730 °C and 1 200 °C. Waste water incineration is typically self-sustaining at COD levels of more than 50 g/l. In the case of low organic loads, a support/auxiliary fuel is needed. |
12.3. Techniques to reduce emissions to air from combustion
|
Technique |
Description |
|
Choice of (support) fuel |
The use of fuel (including support/auxiliary fuel) with a low content of potential pollution-generating compounds (e.g. lower sulphur, ash, nitrogen, mercury, fluorine or chlorine content in the fuel). |
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Low-NOX burner (LNB) and ultra-low-NOX burner (ULNB) |
The technique is based on the principles of reducing peak flame temperatures, delaying but completing the combustion and increasing the heat transfer (increased emissivity of the flame). It may be associated with a modified design of the furnace combustion chamber. The design of ultra-low-NOX burners (ULNB) includes (air/)fuel staging and exhaust/flue-gas recirculation. |
(1) For any parameter where, due to sampling or analytical limitations, 30-minute sampling is inappropriate, a suitable sampling period is employed.
(2) For PCDD/F, a sampling period of 6 to 8 hours is used.
(3) Time-proportional composite samples can be used provided that sufficient flow stability can be demonstrated.
(4) Commission Implementing Decision 2012/119/EU of 10 February 2012 laying down rules concerning guidance on the collection of data and on the drawing up of BAT reference documents and on their quality assurance referred to in Directive 2010/75/EU of the European Parliament and of the Council on industrial emissions (OJ L 63, 2.3.2012, p. 1).
(5) Generic EN standards for continuous measurements are EN 15267-1, -2, and -3, and EN 14181. EN standards for periodic measurements are given in the table.
(6) Refers to the total rated thermal input of all process furnaces/heaters connected to the stack where emissions occur.
(7) In the case of process furnaces/heaters with a total rated thermal input of less than 100 MWth operated less than 500 hours per year, the monitoring frequency may be reduced to at least once every year.
(8) The minimum monitoring frequency for periodic measurements may be reduced to once every 6 months, if the emission levels are proven to be sufficiently stable.
(9) Monitoring of dust does not apply when combusting exclusively gaseous fuels.
(10) Monitoring of NH3 only applies when SCR or SNCR is used.
(11) In the case of process furnaces/heaters combusting gaseous fuels and/or oil with a known sulphur content and where no flue-gas desulphurisation is carried out, continuous monitoring can be replaced either by periodic monitoring with a minimum frequency of once every 3 months or by calculation ensuring the provision of data of an equivalent scientific quality.
(12) The monitoring applies where the pollutant is present in the waste gas based on the inventory of waste gas streams specified by the CWW BAT conclusions.
(13) The minimum monitoring frequency for periodic measurements may be reduced to once every year, if the emission levels are proven to be sufficiently stable.
(14) All (other) processes/sources where the pollutant is present in the waste gas based on the inventory of waste gas streams specified by the CWW BAT conclusions.
(15) EN 15058 and the sampling period need adaptation so that the measured values are representative of the whole decoking cycle.
(16) EN 13284-1 and the sampling period need adaptation so that the measured values are representative of the whole decoking cycle.
(17) The monitoring applies where the chlorine and/or chlorinated compounds are present in the waste gas and thermal treatment is applied
(18) Where the flue gases of two or more furnaces are discharged through a common stack, the BAT-AEL applies to the combined discharge from the stack.
(19) The BAT-AELs do not apply during decoking operations.
(20) No BAT-AEL applies for CO. As an indication, the CO emission level will generally be 10–50 mg/Nm3 expressed as a daily average or an average over the sampling period.
(21) The BAT-AEL only applies when SCR or SNCR are used.
(22) The lower end of the range is achieved when using a thermal oxidiser in the silver process.
(23) The BAT-AEL is expressed as an average of values obtained during 1 year.
(24) In the case of significant methane content in the emission, methane monitored according to EN ISO 25140 or EN ISO 25139 is subtracted from the result.
(25) EO produced is defined as the sum of EO produced for sale and as an intermediate.
(26) The BAT-AEL only applies to combined waste gas streams with flow rates of > 1 000 Nm3/h.
(27) The BAT-AEL is expressed as a daily average or an average over the sampling period.
(28) The BAT-AEL is expressed as an average of values obtained during 1 year. TDI and/or MDI produced refers to the product without residues, in the sense used to define the capacity of the plant.
(29) In the case of NOX values above 100 mg/Nm3 in the sample, the BAT-AEL may be higher and up to 3 mg/Nm3 due to analytical interferences.
(30) In the case of discontinuous waste water discharges, the minimum monitoring frequency is once per discharge.
(31) The BAT-AEPL refers to the product without residues, in the sense used to define the capacity of the plant.
(32) Where the flue-gases of two or more furnaces are discharged through a common stack, the BAT-AEL applies to the combined discharge from the stack.
(33) The BAT-AELs do not apply during decoking operations.
(34) No BAT-AEL applies for CO. As an indication, the CO emission level will generally be 5–35 mg/Nm3 expressed as a daily average or an average over the sampling period.
(35) The minimum monitoring frequency may be reduced to once every month if adequate performance of the solids and copper removal is controlled by frequent monitoring of other parameters (e.g. by continuous measurement of turbidity).
(36) The average of values obtained during 1 month is calculated from the averages of values obtained during each day (at least three spot samples taken at intervals of at least half an hour).
(37) The lower end of the range is typically achieved when the fixed-bed design is used.
(38) The average of values obtained during one year is calculated from the averages of values obtained during each day (at least three spot samples taken at intervals of at least half an hour).
(39) Purified EDC is the sum of EDC produced by oxychlorination and/or direct chlorination and of EDC returned from VCM production to purification.
(40) The BAT-AEL does not apply when the emission is below 150 g/h.
(41) When adsorption is used, the sampling period is representative of a complete adsorption cycle.
(42) In the case of significant methane content in the emission, methane monitored according to EN ISO 25140 or EN ISO 25139 is subtracted from the result.