COMMISSION IMPLEMENTING DECISION (EU) 2022/2427
of 6 December 2022
establishing the best available techniques (BAT) conclusions, under Directive 2010/75/EU of the European Parliament and of the Council on industrial emissions, for common waste gas management and treatment systems in the chemical sector
(notified under document C(2022) 8788)
(Text with EEA relevance)
Article 1
Article 2
ANNEX
1.
Best Available Techniques (BAT) conclusions for Common Waste Gas Management and Treatment Systems in the Chemical Sector
SCOPE
DEFINITIONS
General terms |
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Term used |
Definition |
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Channelled emissions to air |
Emissions of pollutants to air through an emission point such as a stack. |
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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 thermal or catalytic oxidisers. |
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Complex inorganic pigments |
A stable crystal lattice of different metal cations. The most important host-lattices are rutile, spinel, zircon, and haematite/corundum, but other stable structures exist. |
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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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Diffuse emissions |
Non-channelled emissions to air. Diffuse emissions include fugitive and non-fugitive emissions. |
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Emissions to air |
Generic term for emissions of pollutants to air including both channelled and diffuse emissions. |
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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 process furnace/heater |
A process furnace/heater that is not a new process furnace/heater. |
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Flue-gas |
The exhaust gas exiting a combustion unit. |
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Fugitive emissions |
Non-channelled emissions to air caused by loss of tightness of equipment which is designed or assembled to be tight. Fugitive emissions can arise from:
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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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Mass flow |
The mass of a given substance or parameter which is emitted over a defined period of time. |
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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 process furnace/heater |
A process furnace/heater in a plant first permitted following the publication of these BAT conclusions or a complete replacement of a process furnace/heater following the publication of these BAT conclusions. |
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Non-fugitive emissions |
Diffuse emissions other than fugitive emissions. Non-fugitive emissions may arise from, for example, atmospheric vents, bulk storage, loading/unloading systems, vessels and tanks (on opening), open gutters, sampling systems, tank venting, waste, sewers and water treatment plants. |
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NOX precursors |
Nitrogen-containing compounds (e.g. acrylonitrile, ammonia, nitrous gases, nitrogen-containing organic compounds) in the input to thermal or catalytic oxidation that lead to NOX emissions. Elemental nitrogen is not included. |
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Operational constraint |
Limitation or restriction connected, for example, to:
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Periodic measurement |
Measurement at specified time intervals using manual or automated methods. |
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Polymer grade |
For each type of polymer, there are different product qualities (i.e. grades) which vary in structure and molecular mass, and are optimised for specific applications. In the case of polyolefins, these may vary regarding the use of co-polymers such as EVA. In the case of PVC, they may vary in the average length of the polymer chain and in the porosity of the particles. |
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Process furnace/heater |
Process furnaces or heaters are:
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 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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Solvent |
Organic solvent as defined in Article 3(46) of Directive 2010/75/EU. |
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Solvent consumption |
Consumption of solvent as defined in Article 57(9) of Directive 2010/75/EU. |
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Solvent input |
The total quantity of organic solvents used as defined in Part 7 of Annex VII to Directive 2010/75/EU. |
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Solvent mass balance |
A mass balance exercise conducted at least on an annual basis according to Part 7 of Annex VII to Directive 2010/75/EU. |
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Thermal treatment |
Treatment of waste gases using thermal or catalytic oxidation. |
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Total emissions |
The sum of channelled and diffuse emissions. |
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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. |
Substances/Parameters |
|
Term used |
Definition |
Cl2 |
Elemental chlorine. |
CO |
Carbon monoxide. |
CS2 |
Carbon disulphide. |
Dust |
Total particulate matter (in air). Unless specified otherwise, dust includes PM2,5 and PM10. |
EDC |
Ethylene dichloride (1,2-Dichloroethane). |
HCl |
Hydrogen chloride. |
HCN |
Hydrogen cyanide. |
HF |
Hydrogen fluoride. |
H2S |
Hydrogen sulphide. |
NH3 |
Ammonia. |
Ni |
Nickel. |
N2O |
Dinitrogen oxide (also referred to as nitrous oxide). |
NOX |
The sum of nitrogen monoxide (NO) and nitrogen dioxide (NO2), expressed as NO2. |
Pb |
Lead. |
PCDD/F |
Polychlorinated dibenzo-p-dioxins and -furans. |
PM2,5 |
Particulate matter which passes through a size-selective inlet with a 50 % efficiency cut-off at 2,5 μm aerodynamic diameter as defined in Directive 2008/50/EC of the European Parliament and of the Council(2). |
PM10 |
Particulate matter which passes through a size-selective inlet with a 50 % efficiency cut-off at 10 μm aerodynamic diameter as defined in Directive 2008/50/EC. |
SO2 |
Sulphur dioxide. |
SOX |
The sum of sulphur dioxide (SO2), sulphur trioxide (SO3), and sulphuric acid aerosols, expressed as SO2. |
TVOC |
Total volatile organic carbon, expressed as C. |
VCM |
Vinyl chloride monomer. |
VOC |
Volatile organic compound as defined in Article 3(45) of Directive 2010/75/EU. |
ACRONYMS
Acronym |
Definition |
CLP |
Regulation (EC) No 1272/2008 of the European Parliament and of the Council(3) on classification, labelling and packaging of substances and mixtures. |
CMR |
Carcinogenic, mutagenic or toxic for reproduction. |
CMR 1A |
CMR substance of category 1A as defined in Regulation (EC) No 1272/2008 as amended, i.e. carrying the hazard statements H340, H350, H360. |
CMR 1B |
CMR substance of category 1B as defined in Regulation (EC) No 1272/2008 as amended, i.e. carrying the hazard statements H340, H350, H360. |
CMR 2 |
CMR substance of category 2 as defined in Regulation (EC) No 1272/2008 as amended, i.e. carrying the hazard statements H341, H351, H361. |
DIAL |
Differential absorption LIDAR. |
EMS |
Environmental Management System. |
EPS |
Expandable polystyrene. |
E-PVC |
PVC produced by emulsion polymerisation. |
EVA |
Ethylene-vinyl acetate. |
GPPS |
General-purpose polystyrene. |
HDPE |
High-density polyethylene. |
HEAF |
High-efficiency air filter. |
HEPA |
High-efficiency particle air. |
HIPS |
High-impact polystyrene. |
IED |
Directive 2010/75/EU on industrial emissions. |
I-TEQ |
International toxic equivalent – derived by using the equivalence factors in Part 2 of Annex VI to Directive 2010/75/EU. |
LDAR |
Leak detection and repair. |
LDPE |
Low-density polyethylene. |
LIDAR |
Light detection and ranging. |
LLDPE |
Linear low-density polyethylene. |
OGI |
Optical gas imaging. |
OTNOC |
Other than normal operating conditions. |
PP |
Polypropylene. |
PVC |
Polyvinyl chloride. |
REACH |
Regulation (EC) No 1907/2006 of the European Parliament and of the Council(4) concerning the registration, evaluation, authorisation and restriction of chemicals. |
SCR |
Selective catalytic reduction. |
SNCR |
Selective non-catalytic reduction. |
SOF |
Solar occultation flux. |
S-PVC |
PVC produced by suspension polymerisation. |
ULPA |
Ultra-low penetration air. |
GENERAL CONSIDERATIONS
Best Available Techniques
Emission levels associated with the best available techniques (BAT-AELs) and indicative emission levels for channelled emissions to air
Source of emissions |
Reference oxygen level (OR) |
Process furnace/heater using indirect heating |
3 dry vol-% |
All other sources |
No correction for the oxygen level |
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 value of three consecutive samplings/measurements of at least 30 minutes each(5). |
BAT-AELs for diffuse VOC emissions to air
BAT-AELs for total emissions to air for the production of polymers or synthetic rubbers
Production of polyolefins or synthetic rubbers
Production of PVC
Production of viscose
1.1.
General BAT conclusions
1.1.1.
Environmental management systems
BAT 1.
In order to improve the overall environmental performance, BAT is to elaborate and implement an environmental management system (EMS) that incorporates all of the following features:
Note
Applicability
BAT 2.
In order to facilitate the reduction of emissions to air, BAT is to establish, maintain and regularly review (including when a substantial change occurs) an inventory of channelled and diffuse emissions to air, as part of the environmental management system (see BAT 1), that incorporates all of the following features:
Note for diffuse emissions
Applicability
1.1.2.
Other than normal operating conditions (OTNOC)
BAT 3.
In order to reduce the frequency of the occurrence of OTNOC and to reduce emissions to air during OTNOC, BAT is to set up and implement a risk-based OTNOC management plan as part of the environmental management system (see BAT 1) that includes all of the following features:
1.1.3.
Channelled emissions to air
1.1.3.1.
General techniques
BAT 4.
In order to reduce channelled emissions to air, BAT is to use an integrated waste gas management and treatment strategy that includes, in order of priority, process-integrated recovery and abatement techniques.
Description
BAT 5.
In order to facilitate the recovery of materials and the reduction of channelled emissions to air, as well as to increase energy efficiency, BAT is to combine waste gas streams with similar characteristics, thus minimising the number of emission points.
Description
BAT 6.
In order to reduce channelled emissions to air, BAT is to ensure that the waste gas treatment systems are appropriately designed (e.g. considering the maximum flow rate and pollutant concentrations), operated within their design ranges, and maintained (through preventive, corrective, regular and unplanned maintenance) so as to ensure optimal availability, effectiveness and efficiency of the equipment.
1.1.3.2.
Monitoring
BAT 7.
BAT is to continuously monitor key process parameters (e.g. waste gas flow and temperature) of waste gas streams being sent to pretreatment and/or final treatment.
BAT 8.
BAT is to monitor channelled emissions to air 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.
Substance/Parameter(7) |
Process(es)/Source(s) |
Emission points |
Standard(s)(8) |
Minimum monitoring frequency |
Monitoring associated with |
Ammonia (NH3) |
Use of SCR/SNCR |
Any stack |
EN 21877 |
Once every 6 months(9) (10) |
BAT 17 |
All other processes/sources |
BAT 18 |
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Benzene |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
1,3-Butadiene |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Carbon monoxide (CO) |
Thermal treatment |
Any stack with a CO mass flow of ≥ 2 kg/h |
Generic EN standards(11) |
Continuous |
BAT 16 |
Any stack with a CO mass flow of < 2 kg/h |
EN 15058 |
Once every 6 months(9) (10) |
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Process furnaces/heaters |
Any stack with a CO mass flow of ≥ 2 kg/h |
Generic EN standards(11) |
Continuous(12) |
BAT 36 |
|
Any stack with a CO mass flow of < 2 kg/h |
EN 15058 |
Once every 6 months(9) (10) |
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All other processes/sources |
Any stack with a CO mass flow of ≥ 2 kg/h |
Generic EN standards(11) |
Continuous |
BAT 18 |
|
Any stack with a CO mass flow of < 2 kg/h |
EN 15058 |
Once every year(9) (13) |
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Chloromethane |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
CMR substances other than CMR substances covered elsewhere in this table(18) |
All other processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Dichloromethane |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Dust |
All processes/sources |
Any stack with dust mass flow ≥ 3 kg/h |
Generic EN standards(11), EN 13284-1 and EN 13284-2 |
Continuous(14) |
BAT 14 |
Any stack with dust mass flow < 3 kg/h |
EN 13284-1 |
Once every year(9) (13) |
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Elemental chlorine (Cl2) |
All processes/sources |
Any stack |
No EN standard available |
Once every year(9) (13) |
BAT 18 |
Ethylene dichloride (EDC) |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Ethylene oxide |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Formaldehyde |
All processes/sources |
Any stack |
EN standard under development |
Once every 6 months(9) |
BAT 11 |
Gaseous chlorides |
All processes/sources |
Any stack |
EN 1911 |
Once every year(9) (13) |
BAT 18 |
Gaseous fluorides |
All processes/sources |
Any stack |
No EN standard available |
Once every year(9) (13) |
BAT 18 |
Hydrogen cyanide (HCN) |
All processes/sources |
Any stack |
No EN standard available |
Once every year(9) (13) |
BAT 18 |
Lead and its compounds |
All processes/sources |
Any stack |
EN 14385 |
Once every 6 months(9) (15) |
BAT 14 |
Nickel and its compounds |
All processes/sources |
Any stack |
EN 14385 |
Once every 6 months(9) (15) |
BAT 14 |
Nitrous oxide (N2O) |
All processes/sources |
Any stack |
EN ISO 21258 |
Once every year(9) (13) |
– |
Nitrogen oxides (NOX) |
Thermal treatment |
Any stack with a NOX mass flow of ≥ 2,5 kg/h |
Generic EN standards(11) |
Continuous |
BAT 16 |
Any stack with a NOX mass flow of < 2,5 kg/h |
EN 14792 |
Once every 6 months(9) (10) |
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Process furnaces/heaters |
Any stack with a NOX mass flow of ≥ 2,5 kg/h |
Generic EN standards(11) |
Continuous(12) |
BAT 36 |
|
Any stack with a NOX mass flow of < 2,5 kg/h |
EN 14792 |
Once every 6 months(9) (10) |
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All other processes/sources |
Any stack with a NOX mass flow of ≥ 2,5 kg/h |
Generic EN standards(11) |
Continuous |
BAT 18 |
|
Any stack with a NOX mass flow of < 2,5 kg/h |
EN 14792 |
Once every 6 months(9) (10) |
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PCDD/F |
Thermal treatment |
Any stack |
EN 1948-1, EN 1948-2, EN 1948-3 |
Once every 6 months(9) (15) |
BAT 12 |
PM2,5 and PM10 |
All processes/sources |
Any stack |
EN ISO 23210 |
Once every year(9) (13) |
BAT 14 |
Propylene oxide |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Sulphur dioxide (SO2) |
Thermal treatment |
Any stack with a SO2 mass flow of ≥ 2,5 kg/h |
Generic EN standards(11) |
Continuous |
BAT 16 |
Any stack with a SO2 mass flow of < 2,5 kg/h |
EN 14791 |
Once every 6 months(9) (10) |
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Process furnaces/heaters |
Any stack with a SO2 mass flow of ≥ 2,5 kg/h |
Generic EN standards(11) |
Continuous(12) |
BAT 18, BAT 36 |
|
Any stack with a SO2 mass flow of < 2,5 kg/h |
EN 14791 |
Once every 6 months(9) (10) |
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All other processes/sources |
Any stack with a SO2 mass flow of ≥ 2,5 kg/h |
Generic EN standards(11) |
Continuous |
BAT 18 |
|
Any stack with a SO2 mass flow of < 2,5 kg/h |
EN 14791 |
Once every 6 months(9) (10) |
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Tetrachloromethane |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Toluene |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Trichloromethane |
All processes/sources |
Any stack |
No EN standard available |
Once every 6 months(9) |
BAT 11 |
Total volatile organic carbon (TVOC) |
Production of polyolefins(16) |
Any stack with a TVOC mass flow of ≥ 2 kg C/h |
Generic EN standards(11) |
Continuous |
BAT 11, BAT 25 |
Any stack with a TVOC mass flow of < 2 kg C/h |
EN 12619 |
Once every 6 months(9) (10) |
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Production of synthetic rubbers(17) |
Any stack with a TVOC mass flow of ≥ 2 kg C/h |
Generic EN standards(11) |
Continuous |
BAT 11, BAT 32 |
|
Any stack with a TVOC mass flow of < 2 kg C/h |
EN 12619 |
Once every 6 months(9) (10) |
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All other processes/sources |
Any stack with a TVOC mass flow of ≥ 2 kg C/h |
Generic EN standards(11) |
Continuous |
BAT 11 |
|
Any stack with a TVOC mass flow of < 2 kg C/h |
EN 12619 |
Once every 6 months(9) (10) |
1.1.3.3.
Organic compounds
BAT 9.
In order to increase resource efficiency and to reduce the mass flow of organic compounds sent to the final waste gas treatment, BAT is to recover organic compounds from process off-gases by using one or a combination of the techniques given below and to reuse them.
Technique |
Description |
|
a. |
Absorption (regenerative) |
See Section 1.4.1. |
b. |
Adsorption (regenerative) |
See Section 1.4.1. |
c. |
Condensation |
See Section 1.4.1. |
Applicability
BAT 10.
In order to increase energy efficiency and to reduce the mass flow of organic compounds sent to the final waste gas treatment, BAT is to send process off-gases with a sufficient calorific value to a combustion unit that is, if technically possible, combined with heat recovery. BAT 9 has priority over sending process off-gases to a combustion unit.
Description
Applicability
BAT 11.
In order to reduce channelled emissions to air of organic compounds, BAT is to use one or a combination of the techniques given below.
Technique |
Description |
Applicability |
|
a. |
Adsorption |
See Section 1.4.1. |
Generally applicable. |
b. |
Absorption |
See Section 1.4.1. |
Generally applicable. |
c. |
Catalytic oxidation |
See Section 1.4.1. |
Applicability may be restricted by the presence of catalyst poisons in the waste gases. |
d. |
Condensation |
See Section 1.4.1. |
Generally applicable. |
e. |
Thermal oxidation |
See Section 1.4.1. |
Applicability of recuperative and regenerative thermal oxidation to existing plants may be restricted by design and/or operational constraints. Applicability may be restricted where the energy demand is excessive due to the low concentration of the compound(s) concerned in the process off-gases. |
f. |
Bioprocesses |
See Section 1.4.1. |
Only applicable to the treatment of biodegradable compounds. |
Substance/Parameter |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period)(19) |
Total volatile organic carbon (TVOC) |
< 1 -20 (20) (21) (22) (23) |
Sum of VOCs classified as CMR 1A or 1B |
< 1 -5 (24) |
Sum of VOCs classified as CMR 2 |
< 1 -10 (25) |
Benzene |
< 0,5 -1 (26) |
1,3-Butadiene |
< 0,5 -1 (26) |
Ethylene dichloride |
< 0,5 -1 (26) |
Ethylene oxide |
< 0,5 -1 (26) |
Propylene oxide |
< 0,5 -1 (26) |
Formaldehyde |
1 -5 (26) |
Chloromethane |
< 0,5 -1 (27) (28) |
Dichloromethane |
< 0,5 -1 (27) (28) |
Tetrachloromethane |
< 0,5 -1 (27) (28) |
Toluene |
< 0,5 -1 (27) (29) |
Trichloromethane |
< 0,5 -1 (27) (28) |
BAT 12.
In order to reduce channelled emissions to air of PCDD/F from thermal treatment of waste gases containing chlorine and/or chlorinated compounds, BAT is to use techniques a. and b., and one or a combination of techniques c. to e., given below.
Technique |
Description |
Applicability |
|
Specific techniques to reduce PCDD/F emissions |
|||
a. |
Optimised catalytic or thermal oxidation |
See Section 1.4.1. |
Generally applicable. |
b. |
Rapid waste-gas cooling |
Rapid cooling of waste gases from temperatures above 400 °C to below 250 °C to prevent the de novo synthesis of PCDD/F. |
Generally applicable. |
c. |
Adsorption using activated carbon |
See Section 1.4.1. |
Generally applicable. |
d. |
Absorption |
See Section 1.4.1. |
Generally applicable. |
Other techniques not primarily used to reduce PCDD/F emissions |
|||
e. |
Selective catalytic reduction (SCR) |
See Section 1.4.1. When SCR is used for NOX abatement, an adequate catalyst surface of the SCR system also provides for the partial reduction of the emissions of PCDD/F. |
Applicability to existing plants may be restricted by space availability and/or by the presence of catalyst poisons in the waste gases. |
Substance/Parameter |
BAT-AEL (ng I-TEQ/Nm3) (Average over the sampling period) |
PCDD/F |
< 0,01 -0,05 |
1.1.3.4.
Dust (including PM
10
and PM
2,5
) and particulate-bound metals
BAT 13.
In order to increase resource efficiency and to reduce the mass flow of dust and particulate-bound metals sent to the final waste gas treatment, BAT is to recover materials from process off-gases by using one or a combination of the techniques given below and to reuse them.
Technique |
Description |
|
a. |
Cyclone |
See Section 1.4.1. |
b. |
Fabric filter |
See Section 1.4.1. |
c. |
Absorption |
See Section 1.4.1. |
Applicability
BAT 14.
In order to reduce channelled emissions to air of dust and particulate-bound metals, BAT is to use one or a combination of the techniques given below.
Technique |
Description |
Applicability |
|
a. |
Absolute filter |
See Section 1.4.1. |
Applicability may be limited in the case of sticky dust or when the temperature of the waste gases is below the dew point. |
b. |
Absorption |
See Section 1.4.1. |
Generally applicable. |
c. |
Fabric filter |
See Section 1.4.1. |
Applicability may be limited in the case of sticky dust or when the temperature of the waste gases is below the dew point. |
d. |
High-efficiency air filter |
See Section 1.4.1. |
Generally applicable. |
e. |
Cyclone |
See Section 1.4.1. |
Generally applicable. |
f. |
Electrostatic precipitator |
See Section 1.4.1. |
Generally applicable. |
Substance/Parameter |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period) |
Dust |
< 1 -5 (30) (31) (32) (33) |
Lead and its compounds, expressed as Pb |
< 0,01 -0,1 (34) |
Nickel and its compounds, expressed as Ni |
< 0,02 -0,1 (35) |
1.1.3.5.
Inorganic compounds
BAT 15.
In order to increase resource efficiency and to reduce the mass flow of inorganic compounds sent to the final waste gas treatment, BAT is to recover inorganic compounds from process off-gases by using absorption and to reuse them.
Description
Applicability
BAT 16.
In order to reduce channelled emissions to air of CO, NO
X
and SO
X
from thermal treatment, BAT is to use technique c. and one or a combination of the other techniques given below.
Technique |
Description |
Main inorganic compounds targeted |
Applicability |
|
a. |
Choice of fuel |
See Section 1.4.1. |
NOX, SOX |
Generally applicable. |
b. |
Low-NOX burner |
See Section 1.4.1. |
NOX |
Applicability to existing plants may be restricted by design and/or operational constraints. |
c. |
Optimisation of catalytic or thermal oxidation |
See Section 1.4.1. |
CO, NOX |
Generally applicable. |
d. |
Removal of high levels of NOX precursors |
Remove (if possible, for reuse) high levels of NOX precursors prior to thermal or catalytic oxidation, e.g. by absorption, adsorption or condensation. |
NOX |
Generally applicable. |
e. |
Absorption |
See Section 1.4.1. |
SOX |
Generally applicable. |
f. |
Selective catalytic reduction (SCR) |
See Section 1.4.1. |
NOX |
Applicability to existing plants may be restricted by space availability. |
g. |
Selective non-catalytic reduction (SNCR) |
See Section 1.4.1. |
NOX |
Applicability to existing plants may be restricted by the residence time needed for the reaction. |
Substance/Parameter |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period) |
Nitrogen oxides (NOX) from catalytic oxidation |
5 -30 (36) |
Nitrogen oxides (NOX) from thermal oxidation |
5 -130 (37) |
Carbon monoxide (CO) |
No BAT-AEL(38) |
BAT 17.
In order to reduce channelled emissions to air of ammonia from the use of selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) for the abatement of NO
X
emissions (ammonia slip), BAT is to optimise the design and/or operation of SCR or SNCR (e.g. optimised reagent to NO
X
ratio, homogeneous reagent distribution and optimum size of the reagent drops).
Substance/Parameter |
BAT-AEL (mg/Nm3) (Average over the sampling period) |
Ammonia (NH3) from SCR/SNCR |
< 0,5 -8 (39) |
BAT 18.
In order to reduce channelled emissions to air of inorganic compounds other than channelled emissions to air of ammonia from the use of selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) for the abatement of NO
X
emissions), channelled emissions to air of CO, NO
X
and SO
X
from the use of thermal treatment, and channelled emissions to air of NO
X
from process furnaces/heaters, BAT is to use one or a combination of the techniques given below.
Technique |
Description |
Main inorganic compounds targeted |
Applicability |
|
Specific techniques to reduce emissions to air of inorganic compounds |
||||
a. |
Absorption |
See Section 1.4.1. |
Cl2, HCl, HCN, HF, NH3, NOX, SOX |
Generally applicable. |
b. |
Adsorption |
See Section 1.4.1. For the removal of inorganic substances, the technique is often used in combination with a dust abatement technique (see BAT 14). |
HCl, HF, NH3, SOX |
Generally applicable. |
c. |
Selective catalytic reduction (SCR) |
See Section 1.4.1. |
NOX |
Applicability to existing plants may be restricted by space availability. |
d. |
Selective non-catalytic reduction (SNCR) |
See Section 1.4.1. |
NOX |
Applicability to existing plants may be restricted by the residence time needed for the reaction. |
Other techniques not primarily used to reduce emissions to air of inorganic compounds |
||||
e. |
Catalytic oxidation |
See Section 1.4.1. |
NH3 |
Applicability may be restricted by the presence of catalyst poisons in the waste gases. |
f. |
Thermal oxidation |
See Section 1.4.1. |
NH3, HCN |
Applicability of recuperative and regenerative thermal oxidation to existing plants may be restricted by design and/or operational constraints. The applicability may be restricted where the energy demand is excessive due to the low concentration of the compound(s) concerned in the process off-gases. |
Substance/Parameter |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period) |
Ammonia (NH3) |
2 -10 (40) (41) (42) |
Elemental chlorine (Cl2) |
< 0,5 -2 (43) (44) |
Gaseous fluorides, expressed as HF |
≤ 1 (43) |
Hydrogen cyanide (HCN) |
< 0,1 -1 (43) |
Gaseous chlorides, expressed as HCl |
1 -10 (45) |
Nitrogen oxides (NOX) |
10 -150 (46) (47) (48) (49) |
Sulphur oxides (SO2) |
< 3 -150 (48) (50) |
1.1.4.
Diffuse VOC emissions to air
1.1.4.1.
Management system for diffuse VOC emissions
BAT 19.
In order to prevent or, where that is not practicable, to reduce diffuse VOC emissions to air, BAT is to elaborate and implement a management system for diffuse VOC emissions, as part of the environmental management system (see BAT 1), that includes all of the following features:
Applicability
1.1.4.2.
Monitoring
BAT 20.
BAT is to estimate fugitive and non-fugitive VOC emissions to air separately at least once every year by using one or a combination of the techniques given below, as well as to determine the uncertainty of this estimation. The estimation distinguishes between VOCs classified as CMR 1A or 1B and VOCs that are not classified as CMR 1A or 1B.
Note
Technique |
Description |
Type of emissions |
||||||
a. |
Use of emission factors |
See Section 1.4.2. |
Fugitive and/or non-fugitive |
|||||
b. |
Use of a mass balance |
Estimation based on the difference in the mass of the substance inputs to and outputs from the plant/production unit, taking into account the generation and destruction of the substance in the plant/production unit. A mass balance may also consist of measuring the concentration of VOCs in the product (e.g. raw material or solvent). |
||||||
c. |
Use of thermodynamic models |
Estimation using the laws of thermodynamics applied to equipment (e.g. tanks) or particular steps of a production process. The following data are generally used as input for the model:
|
BAT 21.
BAT is to monitor diffuse VOC emissions from the use of solvents by compiling, at least once every year, a solvent mass balance of the solvent inputs and outputs of the plant, as defined in Part 7 of Annex VII to Directive 2010/75/EU and to minimise the uncertainty of the solvent mass balance data by using all of the techniques given below.
Technique |
Description |
|||||||||
a. |
Full identification and quantification of the relevant solvent inputs and outputs, including the associated uncertainty |
This includes:
|
||||||||
b. |
Implementation of a solvent tracking system |
A solvent tracking system aims to keep control of both the used and unused quantities of solvents (e.g. by weighing unused quantities returned to storage from the application area). |
||||||||
c. |
Monitoring of changes that may influence the uncertainty of the solvent mass balance data |
Any change that could influence the uncertainty of the solvent mass balance data is recorded, such as:
|
Applicability
BAT 22.
BAT is to monitor diffuse VOC emissions to air 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.
Type of sources of diffuse VOC emissions(51) (52) |
Type of VOCs |
Standard(s) |
Minimum monitoring frequency |
Sources of fugitive emissions |
VOCs classified as CMR 1A or 1B |
EN 15446(58) |
Once every year(53) (54) (55) |
VOCs not classified as CMR 1A or 1B |
Once during the period covered by each LDAR programme (see BAT 19 point iii.)(56) |
||
Sources of non-fugitive emissions |
VOCs classified as CMR 1A or 1B |
EN 17628 |
Once every year |
VOCs not classified as CMR 1A or 1B |
Once every year(57) |
Note
Applicability
1.1.4.3.
Prevention or reduction of diffuse VOC emissions
BAT 23.
In order to prevent or, where that is not practicable, to reduce diffuse VOC emissions to air, BAT is to use a combination of the techniques given below with the following order of priority.
Note
Technique |
Description |
Type of emissions |
Applicability |
|||||||||||||||
|
||||||||||||||||||
a. |
Limiting the number of emission sources |
This includes:
|
Fugitive and non-fugitive emissions |
Applicability may be restricted by operational constraints in the case of existing plants. |
||||||||||||||
b. |
Use of high-integrity equipment |
High-integrity equipment includes, but is not limited to:
The use of high-integrity equipment is especially relevant to prevent or minimise:
High-integrity equipment is selected, installed and maintained according to the type of process and the process operating conditions. |
Fugitive emissions |
Applicability may be restricted by operational constraints in the case of existing plants. Generally applicable to new plants and major plant upgrades. |
||||||||||||||
c. |
Collecting diffuse emissions and treating off-gases |
Collecting diffuse VOC emissions (e.g. from compressor seals, vents and purge lines) and sending them to recovery (see BAT 9 and BAT 10) and/or abatement (see BAT 11). |
Fugitive and non-fugitive emissions |
Applicability may be restricted:
|
||||||||||||||
|
||||||||||||||||||
d. |
Facilitating access and/or monitoring activities |
To ease maintenance and/or monitoring activities, the access to potentially leaky equipment is facilitated, e.g. by installing platforms, and/or drones are used for monitoring. |
Fugitive emissions |
Applicability may be restricted by operational constraints in the case of existing plants. |
||||||||||||||
e. |
Tightening |
This includes:
|
Fugitive emissions |
Generally applicable. |
||||||||||||||
f. |
Replacement of leaky equipment and/or parts |
This includes the replacement of:
|
Fugitive emissions |
Generally applicable. |
||||||||||||||
g. |
Reviewing and updating process design |
This includes:
|
Non-fugitive emissions |
Applicability may be restricted in the case of existing plants due to operational constraints. |
||||||||||||||
h. |
Reviewing and updating operating conditions |
This includes:
|
Non-fugitive emissions |
Generally applicable. |
||||||||||||||
i. |
Using closed systems |
This includes:
Off-gases from closed systems are sent to recovery (see BAT 9 and BAT 10) and/or abatement (see BAT 11). |
Non-fugitive emissions |
Applicability may be restricted by operational constraints in the case of existing plants and/or by safety concerns. |
||||||||||||||
j. |
Using techniques to minimise emissions from surfaces |
This includes:
|
Non-fugitive emissions |
Applicability may be restricted by operational constraints in the case of existing plants. |
1.1.4.4.
BAT conclusions for the use of solvents or the reuse of recovered solvents
Parameter |
BAT-AEL (percentage of the solvent inputs) (yearly average) (59) |
Diffuse VOC emissions |
≤ 5 % |
1.2.
Polymers and synthetic rubbers
1.2.1.
BAT conclusions for the production of polyolefins
BAT 24.
BAT is to monitor the TVOC concentration in polyolefin products, at least once every year for each representative polyolefin grade produced during the same year, 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.
Polyolefin product |
Standard(s) |
Monitoring associated with |
HDPE, LDPE, LLDPE |
No EN standard available |
BAT 20, BAT 25 |
PP |
||
EPS, GPPS, HIPS |
Note
Applicability
BAT 25.
In order to increase resource efficiency and to reduce emissions to air of organic compounds, BAT is to use all of the techniques given below, as far as applicable.
Technique |
Description |
Applicability |
|
a. |
Chemical agents with low boiling points |
Solvents and suspension agents with low boiling points are used. |
Applicability may be restricted by operational constraints. |
b. |
Lowering the VOC content in the polymer |
The VOC content in the polymer is lowered, e.g. by using low-pressure separation, stripping or closed-loop nitrogen purge systems, devolatilisation extrusion (see Section 1.4.3). The techniques for lowering the VOC content depend on the type of polymer product and production process. |
Devolatilisation extrusion may be restricted by product specifications for the production of HDPE, LDPE and LLDPE. |
c. |
Collection and treatment of process off-gases |
Process off-gases arising from the use of technique b. as well as from the finishing step, e.g. extrusion and degassing silos, are collected and sent to recovery (see BAT 9 and BAT 10) and/or abatement (see BAT 11). |
Applicability may be restricted by operational constraints and/or due to safety concerns (e.g. avoiding concentrations close to the lower/upper explosive limit). |
Polyolefin product |
Unit |
BAT-AEL (Yearly average) |
HDPE |
g C per kg of polyolefins produced |
0,3 -1,0 (60) |
LDPE |
0,1 -1,4 (61) (62) |
|
LLDPE |
0,1 -0,8 |
|
PP |
0,1 -0,9 (60) |
|
GPPS and HIPS |
< 0,1 |
|
EPS |
< 0,6 |
1.2.2.
BAT conclusions for the production of polyvinyl chloride (PVC)
BAT 26.
BAT is to monitor channelled emissions to air 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.
Substance |
Emission points |
Standard(s) |
Minimum monitoring frequency(63) |
Monitoring associated with |
VCM |
Any stack with a VCM mass flow of ≥ 25 g/h |
Generic EN standards(64) |
Continuous(65) |
BAT 29 |
Any stack with a VCM mass flow of < 25 g/h |
No EN standard available |
Once every 6 months(66) (67) |
BAT 27.
BAT is to monitor the residual vinyl chloride monomer concentration in PVC slurry/latex, at least once every year for each representative PVC grade produced during the same year, in accordance with EN standards.
Substance |
Standard(s) |
Monitoring associated with |
VCM |
EN ISO 6401 |
BAT 30 |
Note
BAT 28.
In order to increase resource efficiency and to reduce the mass flow of organic compounds sent to the final waste gas treatment, BAT is to recover the vinyl chloride monomer from process off-gases by using one or a combination of the techniques given below, and to reuse the recovered monomer.
Technique |
Description |
|
a. |
Absorption (regenerative) |
See Section 1.4.1. |
b. |
Adsorption (regenerative) |
See Section 1.4.1. |
c. |
Condensation |
See Section 1.4.1. |
Applicability
BAT 29.
In order to reduce channelled emissions to air of vinyl chloride monomer from the recovery of vinyl chloride monomer, BAT is to use one or a combination of the techniques given below.
|
Technique |
Description |
Applicability |
a. |
Absorption |
See Section 1.4.1. |
Generally applicable |
b. |
Adsorption |
See Section 1.4.1. |
|
c. |
Condensation |
See Section 1.4.1. |
|
d. |
Thermal oxidation |
See Section 1.4.1. |
Applicability of recuperative and regenerative thermal oxidation to existing plants may be restricted by design and/or operational constraints. Applicability may be restricted where the energy demand is excessive due to the low concentration of the compound(s) concerned in the process off-gases. |
Substance |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period) |
VCM |
< 0,5 -1 (68) (69) |
BAT 30.
In order to reduce emissions to air of vinyl chloride monomer, BAT is to use all of the techniques given below.
Technique |
Description |
|||||||||||
a. |
Appropriate VCM storage facilities |
This includes:
|
||||||||||
b. |
Vapour balancing |
See Section 1.4.3. |
||||||||||
c. |
Minimisation of emissions of residual VCM from equipment |
This includes:
|
||||||||||
d. |
Lowering the VCM content in the polymer by stripping |
See Section 1.4.3. |
||||||||||
e. |
Collection and treatment of process off-gases |
Process off-gases from the use of technique d. are collected and sent to VCM recovery (see BAT 28) and/or abatement (see BAT 29). |
PVC type |
Unit |
BAT-AEL (Yearly average) |
S-PVC |
g VCM per kg of PVC produced |
0,01 -0,045 |
E-PVC |
0,25 -0,3 (70) |
PVC type |
Unit |
BAT-AEL (Yearly average) |
S-PVC |
g VCM per kg of PVC produced |
0,01 -0,03 |
E-PVC |
0,2 -0,4 |
1.2.3.
BAT conclusions for the production of synthetic rubbers
BAT 31.
BAT is to monitor the TVOC concentration in synthetic rubbers, at least once every year for each representative synthetic rubber grade produced during the same year, 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.
Substance/Parameter |
Standard(s) |
Monitoring associated with |
VOCs |
No EN standard available |
BAT 32 |
Note
Applicability
BAT 32.
In order to reduce emissions to air of organic compounds, BAT is to use one or a combination of the techniques given below.
|
Technique |
Description |
a. |
Lowering the VOC content in the polymer |
The VOC content in the polymer is lowered by using stripping or devolatilisation extrusion (see Section 1.4.3). |
b. |
Collection and treatment of process off-gases |
Process off-gases are collected and sent to recovery (see BAT 9 and BAT 10) and/or abatement (see BAT 11). |
Substance/Parameter |
Unit |
BAT-AEL (Yearly average) |
TVOC |
g C per kg of synthetic rubber produced |
0,2 -4,2 |
1.2.4.
BAT conclusions for the production of viscose using CS
2
BAT 33.
BAT is to monitor channelled emissions to air 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.
Substance(71) |
Emission points |
Standard(s) |
Minimum monitoring frequency |
Monitoring associated with |
Carbon disulphide (CS2) |
Any stack with a mass flow of ≥ 1 kg/h |
Generic EN standards(72) |
Continuous(73) |
BAT 35 |
Any stack with a mass flow of < 1 kg/h |
No EN standard available |
Once every year(74) |
||
Hydrogen sulphide (H2S) |
Any stack with a mass flow of ≥ 50 g/h |
Generic EN standards(72) |
Continuous(73) |
|
Any stack with a mass flow of < 50 g/h |
No EN standard available |
Once every year(74) |
BAT 34.
In order to increase resource efficiency and to reduce the mass flow of CS
2
and H
2
S sent to the final waste gas treatment, BAT is to recover CS
2
by using technique a. and/or technique b. or a combination of technique c. with technique(s) a. and/or b., given below and to reuse the CS
2
, or, alternatively, to use technique d.
Technique |
Main substance targeted |
Description |
Applicability |
|
a. |
Absorption (regenerative) |
H2S |
See Section 1.4.1. |
Generally applicable for the production of casing. For other products, applicability may be restricted where the energy demand is excessive due to high waste gas volume flows (above e.g. 120 000 Nm3/h) or low H2S concentration in the waste gas (below e.g. 0,5 g/Nm3). |
b. |
Adsorption (regenerative) |
H2S, CS2 |
See Section 1.4.1. |
Applicability may be restricted where the energy demand for recovery is excessive if the concentration of CS2 in the waste gas is below e.g. 5 g/Nm3. |
c. |
Condensation |
H2S, CS2 |
See Section 1.4.1. |
|
d. |
Production of sulphuric acid |
H2S, CS2 |
Process off-gases containing CS2 and H2S are used to produce sulphuric acid. |
Applicability may be restricted if the concentration of CS2 and/or H2S in the waste gas is below 5 g/Nm3. |
BAT 35.
In order to reduce channelled emissions to air of CS
2
and H
2
S, BAT is to use one or a combination of the techniques given below.
Technique |
Main substance targeted |
Description |
Applicability |
|
a. |
Absorption |
H2S |
See Section 1.4.1. |
Generally applicable. |
b. |
Bioprocesses |
CS2, H2S |
See Section 1.4.1. |
Applicability may be restricted where the energy demand is excessive due to high waste gas volume flows (e.g. above 60 000 Nm3/h) or high CS2 concentration in the waste gas (e.g. above 1 000 mg/Nm3) or too low H2S concentration. |
c. |
Thermal oxidation |
CS2, H2S |
See Section 1.4.1. |
Applicability of recuperative and regenerative thermal oxidation to existing plants may be restricted by design and/or operational constraints. Applicability may be restricted where the energy demand is excessive due to the low concentration of the compound(s) concerned in the process off-gases. |
Substance |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period)(75) |
CS2 |
5 -400 (76) (77) |
H2S |
1 -10 (78) |
Parameter |
Process |
Unit |
BAT-AEL (Yearly average) |
Sum of H2S and CS2 (expressed as Total S)(79) |
Production of staple fibres |
g Total S per kg of product |
6 -9 |
Casing |
120 -250 |
1.3.
Process furnaces/heaters
BAT 36.
In order to prevent or, where that is not practicable, to reduce channelled emissions to air of CO, dust, NO
X
and SO
X
, BAT is to use technique c. and one or a combination of the other techniques given below.
Technique |
Description |
Main inorganic compounds targeted |
Applicability |
|
Primary techniques |
||||
a. |
Choice of fuel |
See Section 1.4.1. This includes switching from liquid to gaseous fuels, taking into account the overall hydrocarbon balance. |
NOX, SOX, dust |
The switch from liquid to gaseous fuels may be restricted by the design of the burners in the case of existing process furnaces/heaters. |
b. |
Low-NOX burner |
See Section 1.4.1. |
NOX |
For existing process furnaces/heaters, the applicability may be restricted by their design. |
c. |
Optimised combustion |
See Section 1.4.1. |
CO, NOX |
Generally applicable. |
Secondary techniques |
||||
d. |
Absorption |
See Section 1.4.1. |
SOX, dust |
Applicability may be restricted for existing process furnaces/heaters by space availability. |
e. |
Fabric filter or absolute filter |
See Section 1.4.1. |
Dust |
Not applicable when only combusting gaseous fuels. |
f. |
Selective catalytic reduction (SCR) |
See Section 1.4.1. |
NOX |
Applicability to existing process furnaces/heaters may be restricted by space availability. |
g. |
Selective non-catalytic reduction (SNCR) |
See Section 1.4.1. |
NOX |
Applicability to existing process furnaces/heaters may be restricted by the temperature window (800-1 100 °C) and the residence time needed for the reaction. |
Parameter |
BAT-AEL (mg/Nm3) (Daily average or average over the sampling period) |
Nitrogen oxides (NOX) |
30 -150 (80) (81) (82) |
Carbon monoxide (CO) |
No BAT-AEL(83) |
1.4.
Description of techniques
1.4.1.
Techniques to reduce channelled emissions to air
Technique |
Description |
||||||
Absorption |
The removal of gaseous or particulate pollutants from a process off-gas or waste gas stream via mass transfer to a suitable liquid, often water or an aqueous solution. It may involve a chemical reaction (e.g. in an acid or alkaline scrubber). In the case of regenerative absorption, the compounds may be recovered from the liquid. |
||||||
Adsorption |
The removal of pollutants from a process off-gas or waste gas stream by retention on a solid surface (activated carbon is typically used as the adsorbent). Adsorption may be regenerative or non-regenerative. In non-regenerative adsorption, the spent adsorbent is not regenerated but disposed of. In the case of regenerative adsorption, 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. |
||||||
Bioprocesses |
Bioprocesses include the following:
|
||||||
Choice of fuel |
The use of fuel (including support/auxiliary fuel) with a low content of potential pollution-generating compounds (e.g. low sulphur, ash, nitrogen, fluorine or chlorine content in the fuel). |
||||||
Condensation |
The removal of 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, different cooling media are used, e.g. water or brine. In cryogenic condensation, liquid nitrogen is used as a cooling medium. |
||||||
Cyclone |
Equipment for the removal of dust from a process off-gas or waste gas stream based on imparting centrifugal forces, usually within a conical chamber. |
||||||
Electrostatic precipitator |
An electrostatic precipitator (ESP) is a particulate control device that uses electrical forces to move particles entrained within a 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. The pulsating DC voltage required is in the range of 20-100 kV. |
||||||
Absolute filter |
Absolute filters, also referred to as high-efficiency particle air (HEPA) filters or ultra-low penetration air (ULPA) filters, are constructed from glass cloth or fabrics of synthetic fibres through which gases are passed to remove particles. Absolute filters show higher efficiencies than fabric filters. The classification of HEPA and ULPA filters according to their performance is given in EN 1822-1. |
||||||
High-efficiency air filter (HEAF) |
A flat-bed filter in which aerosols combine into droplets. Highly viscous droplets remain on the filter fabric which contains the residues to be disposed of and separated into droplets, aerosols and dust. HEAFs are particularly suitable for treating highly viscous droplets. |
||||||
Fabric filter |
Fabric filters, often referred to as bag filters, are constructed from porous woven or felted fabric through which gases are passed to remove particles. The use of a fabric filter requires the selection of a fabric suitable for the characteristics of the waste gas and the maximum operating temperature. |
||||||
Low-NOX burner |
The technique (including ultra-low-NOX burner) is based on the principles of reducing peak flame temperatures. The air/fuel mixing reduces the availability of oxygen and reduces the peak flame temperature, thus retarding the conversion of fuel-bound nitrogen to NOX and the formation of thermal NOX, while maintaining high combustion efficiency. The design of ultra-low-NOX burners includes (air/)fuel staging and exhaust/flue-gas recirculation. |
||||||
Optimised combustion |
Good design of the combustion chambers, burners and associated equipment/devices is combined with optimisation of combustion conditions (e.g. the temperature and residence time in the combustion zone, efficient mixing of the fuel and combustion air) and the regular planned maintenance of the combustion system according to suppliers’ recommendations. Combustion conditions 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). |
||||||
Optimisation of catalytic or thermal oxidation |
Optimisation of design and operation of catalytic or thermal oxidation to promote the oxidation of organic compounds including PCDD/F present in the waste gases, to prevent PCDD/F and the (re)formation of their precursors, as well as to reduce the generation of pollutants such as NOX and CO. |
||||||
Catalytic oxidation |
Abatement technique which oxidises combustible compounds in a waste gas stream with air or oxygen in a catalyst bed. The catalyst enables oxidation at lower temperatures and in smaller equipment compared to thermal oxidation. The typical oxidation temperature is between 200 °C and 600 °C. For process off-gases with low VOC concentrations (e.g. < 1 g/Nm3), pre-concentration steps may be applied using adsorption (rotor or fixed bed, with activated carbon or zeolites). VOCs adsorbed in the concentrator are desorbed by using heated ambient air or heated waste gas, and the resulting volume flow with higher VOC concentration is directed to the oxidiser. Molecular sieves (‘smoothers’), typically composed of zeolites, may be used before the concentrators or the oxidiser to level down high variations of VOC concentrations in the process off-gases. |
||||||
Thermal oxidation |
Abatement technique which oxidises combustible compounds in a 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. The typical combustion temperature is between 800 °C and 1 000 °C. Several types of thermal oxidation are operated:
For process off-gases with low VOC concentrations (e.g. < 1 g/Nm3), pre-concentration steps may be applied using adsorption (rotor or fixed bed, with activated carbon or zeolites). VOCs adsorbed in the concentrator are desorbed by using heated ambient air or heated waste gas, and the resulting volume flow with higher VOC concentration is directed to the oxidiser. Molecular sieves (‘smoothers’), typically composed of zeolites, may be used before the concentrators or the oxidiser to level down high variations of VOC concentrations in the process off-gases. |
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Selective catalytic reduction (SCR) |
Selective reduction of nitrogen oxides with ammonia or urea in the presence of a catalyst. The technique is based on the reduction of NOX to nitrogen in a catalytic bed by reaction with ammonia at an optimum operating temperature that is typically around 200– 450 °C. In general, ammonia is injected as an aqueous solution; the ammonia source can also be anhydrous ammonia or a urea solution. Several layers of catalyst may be applied. A higher NOX reduction is achieved with the use of a larger catalyst surface, installed as one or more layers. ‘In-duct’ or ‘slip’ SCR combines SNCR with downstream SCR which reduces the ammonia slip from SNCR. |
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Selective non-catalytic reduction (SNCR) |
Selective reduction of nitrogen oxides to nitrogen with ammonia or urea at high temperatures and without catalyst. The operating temperature window is maintained between 800 °C and 1 000 °C for optimal reaction. |
1.4.2.
Techniques to monitor diffuse emissions to air
Technique |
Description |
Differential absorption LIDAR (DIAL) |
A laser-based technique using differential absorption LIDAR (light detection and ranging), which is the optical analogue of radio-wave-based RADAR. The technique relies on the back-scattering of laser beam pulses by atmospheric aerosols, and the analysis of the spectral properties of the returned light collected with a telescope. |
Emission factor |
Emission factors are numbers that can be multiplied by an activity rate (e.g. the production output), in order to estimate the emissions from the installation. Emission factors are generally derived through the testing of a population of similar process equipment or process steps. This information can be used to relate the quantity of material emitted to some general measure of the scale of activity. In the absence of other information, default emission factors (e.g. literature values) can be used to provide an estimate of the emissions. Emission factors are usually expressed as the mass of a substance emitted divided by the throughput of the process emitting the substance. |
Leak Detection and Repair (LDAR) programme |
A structured approach to reduce fugitive VOC emissions by detection and subsequent repair or replacement of leaking components. The LDAR programme consists of one or more campaigns. A campaign is usually conducted over 1 year, where a certain percentage of the pieces of equipment is monitored. |
Optical gas imaging (OGI) methods |
Optical gas imaging uses small lightweight hand-held or fixed cameras which enable the visualisation of gas leaks in real time, so that they appear as ‘smoke’ on a video recorder together with the image of the equipment concerned, to easily and rapidly locate significant VOC leaks. Active systems produce an image with a back-scattered infrared laser light reflected on the equipment and its surroundings. Passive systems are based on the natural infrared radiation of the equipment and its surroundings. |
Solar occultation flux (SOF) |
The technique is based on the recording and spectrometric Fourier Transform analysis of a broadband infrared or ultraviolet/visible sunlight spectrum along a given geographical itinerary, crossing the wind direction and cutting through VOC plumes. |
1.4.3.
Techniques to reduce diffuse emissions
Technique |
Description |
Devolatilisation extrusion |
When the concentrated rubber solution is further processed by extrusion, the solvent vapours (commonly cyclohexane, hexane, heptane, toluene, cyclopentane, isopentane or mixtures thereof) coming from the vent hole of the extruder are compressed and sent to recovery. |
Stripping |
VOCs contained in the polymer are transferred to the gaseous phase (e.g. by using steam). The removal efficiency may be optimised by a suitable combination of temperature, pressure and residence time and by maximising the ratio of free polymer surface to total polymer volume. |
Vapour balancing |
The vapour from a piece of receiving equipment (e.g. a tank) that is displaced during the transfer of a liquid and is returned to the delivery equipment from which the liquid is delivered. |