Commission Implementing Decision
of 9 October 2014
establishing best available techniques (BAT) conclusions, under Directive 2010/75/EU of the European Parliament and of the Council on industrial emissions, for the refining of mineral oil and gas
(notified under document C(2014) 7155)
(Text with EEA relevance)
(2014/738/EU)
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)Article 13(1) of Directive 2010/75/EU requires the Commission to organise an exchange of information on industrial emissions between it and Member States, the industries concerned and non-governmental organisations promoting environmental protection in order to facilitate the drawing up of best available techniques (BAT) reference documents as defined in Article 3(11) of that Directive.
(2)In accordance with Article 13(2) of Directive 2010/75/EU, the exchange of information is to address the performance of installations and techniques in terms of emissions, expressed as short- and long-term averages, where appropriate, and the associated reference conditions, consumption and nature of raw materials, water consumption, use of energy and generation of waste and the techniques used, associated monitoring, cross-media effects, economic and technical viability and developments therein and best available techniques and emerging techniques identified after considering the issues mentioned in points (a) and (b) of Article 13(2) of that Directive.
(3)‘BAT conclusions’ as defined in Article 3(12) of Directive 2010/75/EU are the key element of BAT reference documents and lay down the conclusions on best available techniques, their description, information to assess their applicability, the emission levels associated with the best available techniques, associated monitoring, associated consumption levels and, where appropriate, relevant site remediation measures.
(4)In accordance with Article 14(3) of Directive 2010/75/EU, BAT conclusions are to be the reference for setting permit conditions for installations covered by Chapter II of that Directive.
(5)Article 15(3) of Directive 2010/75/EU requires the competent authority to set emission limit values that ensure that, under normal operating conditions, emissions do not exceed the emission levels associated with the best available techniques as laid down in the decisions on BAT conclusions referred to in Article 13(5) of Directive 2010/75/EU.
(6)Article 15(4) of Directive 2010/75/EU provides for derogations from the requirement laid down in Article 15(3) only where the costs associated with the achievement of the emission levels associated with the BAT disproportionately outweigh the environmental benefits due to the geographical location, the local environmental conditions or the technical characteristics of the installation concerned.
(7)Article 16(1) of Directive 2010/75/EU provides that the monitoring requirements in the permit referred to in point (c) of Article 14(1) of the Directive are to be based on the conclusions on monitoring as described in the BAT conclusions.
(8)In accordance with Article 21(3) of Directive 2010/75/EU, within 4 years of publication of decisions on BAT conclusions, the competent authority is to reconsider and, if necessary, update all the permit conditions and ensure that the installation complies with those permit conditions.
(9)The Commission established a forum composed of representatives of Member States, the industries concerned and non-governmental organisations promoting environmental protection by Decision of 16 May 2011 establishing a forum for the exchange of information pursuant to Article 13 of Directive 2010/75/EU on industrial emissions(2).
(10)In accordance with Article 13(4) of Directive 2010/75/EU, the Commission obtained the opinion of the forum, established by Decision of 16 May 2011, on the proposed content of the BAT reference document for the refining of mineral oil and gas on 20 September 2013 and made it publicly available.
(11)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 BAT conclusions for the refining of mineral oil and gas, as set out in the Annex, are adopted.
Article 2Application and Interpretation
1.The BAT conclusions referred to in Article 1 apply in the United Kingdom.
2.In this Decision—
“BAT conclusions” has the meaning given in Article 2 of Decision 2012/134/EU (“Decision 2012/134/EU”) establishing the best available techniques (BAT) conclusions under Directive 2010/75/EU of the European Parliament and of the Council on industrial emissions for the manufacture of glass;
“best available techniques” has the meaning given in Article 2 of Decision 2012/134/EU.
3.In the Annex, references to “Member States” are to be read as if the United Kingdom were a Member State.
ANNEXBAT CONCLUSIONS FOR THE REFINING OF MINERAL OIL AND GAS
SCOPE
These BAT conclusions cover certain industrial activities specified in Section 1.2 of Annex I to Directive 2010/75/EU, namely ‘1.2. Refining of mineral oil and gas’.
In particular, these BAT conclusions cover the following processes and activities:
| Activity | Subactivities or processes included in activity |
|---|---|
| Alkylation | All alkylation processes: hydrofluoric acid (HF), sulphuric acid (H2SO4) and solid-acid |
| Base oil production | Deasphalting, aromatic extraction, wax processing and lubricant oil hydrofinishing |
| Bitumen production | All techniques from storage to final product additives |
| Catalytic cracking | All types of catalytic cracking units such as fluid catalytic cracking |
| Catalytic reforming | Continuous, cyclic and semi-regenerative catalytic reforming |
| Coking | Delayed and fluid coking processes. Coke calcination |
| Cooling | Cooling techniques applied in refineries |
| Desalting | Desalting of crude oil |
| Combustion units for energy production | Combustion units burning refinery fuels, excluding units using only conventional or commercial fuels |
| Etherification | Production of chemicals (e.g. alcohols and ethers such as MTBE, ETBE and TAME) used as motor fuels additives |
| Gas separation | Separation of light fractions of the crude oil e.g. refinery fuel gas (RFG), liquefied petroleum gas (LPG) |
| Hydrogen consuming processes | Hydrocracking, hydrorefining, hydrotreatments, hydroconversion, hydroprocessing and hydrogenation processes |
| Hydrogen production | Partial oxidation, steam reforming, gas heated reforming and hydrogen purification |
| Isomerisation | Isomerisation of hydrocarbon compounds C4, C5 and C6 |
| Natural gas plants | Natural gas (NG) processing including liquefaction of NG |
| Polymerisation | Polymerisation, dimerisation and condensation |
| Primary distillation | Atmospheric and vacuum distillation |
| Product treatments | Sweetening and final product treatments |
| Storage and handling of refinery materials | Storage, blending, loading and unloading of refinery materials |
| Visbreaking and other thermal conversions | Thermal treatments such as visbreaking or thermal gas oil process |
| Waste gas treatment | Techniques to reduce or abate emissions to air |
| Waste water treatment | Techniques to treat waste water prior to release |
| Waste management | Techniques to prevent or reduce the generation of waste |
These BAT conclusions do not address the following activities or processes:
the exploration and production of crude oil and natural gas;
the transportation of crude oil and natural gas;
the marketing and distribution of products.
Other reference documents which may be relevant for the activities covered by these BAT conclusions are the following:
| Reference document | Subject |
|---|---|
| Common Waste Water and Waste Gas Treatment/Management Systems in the Chemical Sector (CWW) | Waste water management and treatment techniques |
| Industrial Cooling Systems (ICS) | Cooling processes |
| Economics and Cross-media Effects (ECM) | Economics and cross-media effects of techniques |
| Emissions from Storage (EFS) | Storage, blending, loading and unloading of refinery materials |
| Energy Efficiency (ENE) | Energy efficiency and integrated refinery management |
| Large Combustion Plants (LCP) | Combustion of conventional and commercial fuels |
| Large Volume Inorganic Chemicals — Ammonia, Acids and Fertilisers Industries (LVIC-AAF) | Steam reforming and hydrogen purification |
| Large Volume Organic Chemical Industry (LVOC) | Etherification process (MTBE, ETBE and TAME production) |
| Waste Incineration (WI) | Waste incineration |
| Waste Treatment (WT) | Waste treatment |
| General Principles of Monitoring (MON) | Monitoring of emissions to air and water |
GENERAL CONSIDERATIONS
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, these BAT conclusions are generally applicable.
Averaging periods and reference conditions for emissions to air
Unless stated otherwise, emission levels associated with the best available techniques (BAT-AELs) for emissions to air given in these BAT conclusions refer to concentrations, expressed as mass of emitted substance per volume of waste gas under the following standard conditions: dry gas, temperature of 273,15 K, pressure of 101,3 kPa.
| For continuous measurements | BAT-AELs refer to monthly average values, which are the averages of all valid hourly average values measured over a period of one month |
| For periodic measurements | BAT-AELs refer to the average value of three spot samples of at least 30 minutes each |
For combustion units, catalytic cracking processes, and waste gas sulphur recovery units, reference conditions for oxygen are shown in Table 1.
Table 1
Reference conditions for BAT-AELs concerning emissions to air
a In case of applying BAT 58. | ||
| Activities | Unit | Oxygen reference conditions |
|---|---|---|
| Combustion unit using liquid or gaseous fuels with the exception of gas turbines and engines | mg/Nm3 | 3 % oxygen by volume |
| Combustion unit using solid fuels | mg/Nm3 | 6 % oxygen by volume |
| Gas turbines (including combined cycle gas turbines — CCGT) and engines | mg/Nm3 | 15 % oxygen by volume |
| Catalytic cracking process (regenerator) | mg/Nm3 | 3 % oxygen by volume |
| Waste gas sulphur recovery unita | mg/Nm3 | 3 % oxygen by volume |
Conversion of emissions concentration to reference oxygen level
The formula for calculating the emissions concentration at a reference oxygen level (see Table 1) is shown below.
Where:
:
emissions concentration referred to the reference oxygen level OR
:
reference oxygen level
:
emissions concentration referred to the measured oxygen level OM
:
measured oxygen level.
Averaging periods and reference conditions for emissions to water
Unless stated otherwise, emission levels associated with the best available techniques (BAT-AELs) for emissions to water given in these BAT conclusions refer to values of concentration (mass of emitted substances per volume of water) expressed in mg/l.
Unless stated otherwise, the averaging periods associated with the BAT-AELs are defined as follows:
| Daily average | Average over a sampling period of 24 hours taken as a flow-proportional composite sample or, provided that sufficient flow stability is demonstrated, from a time-proportional sample |
| Yearly/Monthly average | Average of all daily averages obtained within a year/month, weighted according to the daily flows |
DEFINITIONS
For the purpose of these BAT conclusions, the following definitions apply:
| Term used | Definition |
|---|---|
| Unit | A segment/subpart of the installation in which a specific processing operation is conducted |
| New unit | A unit first permitted on the site of the installation following the publication of these BAT conclusions or a complete replacement of a unit on the existing foundations of the installation following the publication of these BAT conclusions |
| Existing unit | A unit which is not a new unit |
| Process off-gas | The collected gas generated by a process which must be treated e.g. in an acid gas removal unit and a sulphur recovery unit (SRU) |
| Flue-gas | The exhaust gas exiting a unit after an oxidation step, generally combustion (e.g. regenerator, Claus unit) |
| Tail gas | Common name of the exhaust gas from an SRU (generally Claus process) |
| VOC | Volatile organic compounds as defined in Article 3(45) of Directive 2010/75/EU |
| NMVOC | VOC excluding methane |
| Diffuse VOC emissions | Non-channelled VOC emissions that are not released via specific emission points such as stacks. They can result from ‘area’ sources (e.g. tanks) or ‘point’ sources (e.g. pipe flanges) |
| NOX expressed as NO2 | The sum of nitrogen oxide (NO) and nitrogen dioxide (NO2) expressed as NO2 |
| SOX expressed as SO2 | The sum of sulphur dioxide (SO2) and sulphur trioxide (SO3) expressed as SO2 |
| H2S | Hydrogen sulphide. Carbonyl sulphide and mercaptan are not included |
| Hydrogen chloride expressed as HCl | All gaseous chlorides expressed as HCl |
| Hydrogen fluoride expressed as HF | All gaseous fluorides expressed as HF |
| FCC unit | Fluid catalytic cracking: a conversion process for upgrading heavy hydrocarbons, using heat and a catalyst to break larger hydrocarbon molecules into lighter molecules |
| SRU | Sulphur recovery unit. See definition in Section 1.20.3 |
| Refinery fuel | Solid, liquid or gaseous combustible material from the distillation and conversion steps of the refining of crude oil. Examples are refinery fuel gas (RFG), syngas and refinery oils, pet coke |
| RFG | Refinery fuel gas: off-gases from distillation or conversion units used as a fuel |
| Combustion unit | Unit burning refinery fuels alone or with other fuels for the production of energy at the refinery site, such as boilers (except CO boilers), furnaces, and gas turbines. |
| Continuous measurement | Measurement using an ‘automated measuring system’ (AMS) or a ‘continuous emission monitoring system’ (CEMS) permanently installed on site |
| Periodic measurement | Determination of a measurand at specified time intervals using manual or automated reference methods |
| Indirect monitoring of emissions to air | Estimation of the emissions concentration in the flue-gas of a pollutant obtained through an appropriate combination of measurements of surrogate parameters (such as O2 content, sulphur or nitrogen content in the feed/fuel), calculations and periodic stack measurements. The use of emission ratios based on S content in the fuel is one example of indirect monitoring. Another example of indirect monitoring is the use of PEMS |
| Predictive Emissions monitoring system (PEMS) | System to determine the emissions concentration of a pollutant based on its relationship with a number of characteristic continuously monitored process parameters (e.g. fuel-gas consumption, air/fuel ratio) and fuel or feed quality data (e.g. the sulphur content) of an emission source |
| Volatile liquid hydrocarbon compounds | Petroleum derivatives with a Reid vapour pressure (RVP) of more than 4 kPa, such as naphtha and aromatics |
| Recovery rate | Percentage of NMVOC recovered from the streams conveyed into a vapour recovery unit (VRU) |
1.1.General BAT conclusions for the refining of mineral oil and gas
The process-specific BAT conclusions included in Sections 1.2 to 1.19 apply in addition to the general BAT conclusions mentioned in this section.
1.1.1.Environmental management systems
BAT 1.In order to improve the overall environmental performance of plants for the refining of mineral oil and gas, BAT is to implement and adhere to an environmental management system (EMS) that incorporates all of the following features:
commitment of the management, including senior management;
definition of an environmental policy that includes the continuous improvement for the installation by the management;
planning and establishing the necessary procedures, objectives and targets, in conjunction with financial planning and investment;
implementation of the procedures paying particular attention to:
structure and responsibility
training, awareness and competence
communication
employee involvement
documentation
efficient process control
maintenance programmes
emergency preparedness and response
safeguarding compliance with environmental legislation.
checking performance and taking corrective action, paying particular attention to:
monitoring and measurement (see also the reference document on the General Principles of Monitoring)
corrective and preventive action
maintenance of records
independent (where practicable) internal and external auditing in order to determine whether or not the EMS conforms to planned arrangements and has been properly implemented and maintained;
review of the EMS and its continuing suitability, adequacy and effectiveness by senior management;
following the development of cleaner technologies;
consideration for the environmental impacts from the eventual decommissioning of the installation at the stage of designing a new plant, and throughout its operating life;
application of sectoral benchmarking on a regular basis.
Applicability
The scope (e.g. level of detail) and nature of the EMS (e.g. standardised or non-standardised) will generally be related to the nature, scale and complexity of the installation, and the range of environmental impacts it may have.
1.1.2.Energy efficiency
BAT 2.In order to use energy efficiently, BAT is to use an appropriate combination of the techniques given below.
1.1.3.Solid materials storage and handling
BAT 3.In order to prevent or, where that is not practicable, to reduce dust emissions from the storage and handling of dusty materials, BAT is to use one or a combination of the techniques given below:
store bulk powder materials in enclosed silos equipped with a dust abatement system (e.g. fabric filter);
store fine materials in enclosed containers or sealed bags;
keep stockpiles of coarse dusty material wetted, stabilise the surface with crusting agents, or store under cover in stockpiles;
use road cleaning vehicles.
1.1.4.Monitoring of emissions to air and key process parameters
BAT 4.BAT is to monitor emissions to air by using the monitoring techniques with at least the minimum 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.
a Continuous measurement of SO2 emissions may be replaced by calculations based on measurements of the sulphur content of the fuel or the feed; where it can be demonstrated that this leads to an equivalent level of accuracy. | |||
b Regarding SOX, only SO2 is continuously measured, while SO3 is only periodically measured (e.g. during calibration of the SO2 monitoring system). | |||
c Refers to the total rated thermal input of all combustion units connected to the stack where emissions occur. | |||
d Or indirect monitoring of SOX. | |||
e Monitoring frequencies may be adapted if, after a period of one year, the data series clearly demonstrate a sufficient stability. | |||
f SO2 emissions measurements from SRU may be replaced by a continuous material balance or other relevant process parameter monitoring, provided appropriate measurements of SRU efficiency are based on periodic (e.g. once every 2 years) plant performance tests. | |||
g Antimony (Sb) is monitored only in catalytic cracking units when Sb injection is used in the process (e.g. for metals passivation). | |||
h With the exception of combustion units firing only gaseous fuels. | |||
| Description | Unit | Minimum frequency | Monitoring technique |
|---|---|---|---|
(i) SOX, NOX, and dust emissions | Catalytic cracking | Continuousab | Direct measurement |
Combustion units ≥ 100 MWc and calcining units | Continuousab | Direct measurementd | |
Combustion units of 50 to 100 MWc | Continuousab | Direct measurement or indirect monitoring | |
Combustion units < 50 MWc | Once a year and after significant fuel changese | Direct measurement or indirect monitoring | |
| Sulphur recovery units (SRU) | Continuous for SO2 only | Direct measurement or indirect monitoringf | |
(ii) NH3 emissions | All units equipped with SCR or SNCR | Continuous | Direct measurement |
(iii) CO emissions | Catalytic cracking and combustion units ≥ 100 MWc | Continuous | Direct measurement |
| Other combustion units | Once every 6 monthse | Direct measurement | |
(iv) Metals emissions: Nickel (Ni), Antimony (Sb)g, Vanadium (V) | Catalytic cracking | Once every 6 months and after significant changes to the unite | Direct measurement or analysis based on metals content in the catalyst fines and in the fuel |
| Combustion unitsh | |||
(v) Polychlorinated dibenzodioxins/furans (PCDD/F) emissions | Catalytic reformer | Once a year or once a regeneration, whichever is longer | Direct measurement |
BAT 5.BAT is to monitor the relevant process parameters linked to pollutant emissions, at catalytic cracking and combustion units by using appropriate techniques and with at least the frequency given below.
a N and S monitoring in fuel or feed may not be necessary when continuous emission measurements of NOX and SO2 are carried out at the stack. | |
| Description | Minimum frequency |
|---|---|
| Monitoring of parameters linked to pollutant emissions, e.g. O2 content in flue-gas, N and S content in fuel or feeda | Continuous for O2 content. For N and S content, periodic at a frequency based on significant fuel/feed changes |
BAT 6.BAT is to monitor diffuse VOC emissions to air from the entire site by using all of the following techniques:
sniffing methods associated with correlation curves for key equipment;
optical gas imaging techniques;
calculations of chronic emissions based on emissions factors periodically (e.g. once every two years) validated by measurements.
The screening and quantification of site emissions by periodic campaigns with optical absorption-based techniques, such as differential absorption light detection and ranging (DIAL) or solar occultation flux (SOF) is a useful complementary technique.
Description
See Section 1.20.6.
1.1.5.Operation of waste gas treatment systems
BAT 7.In order to prevent or reduce emissions to air, BAT is to operate the acid gas removal units, sulphur recovery units and all other waste gas treatment systems with a high availability and at optimal capacity.
Description
Special procedures can be defined for other than normal operating conditions, in particular:
during start-up and shutdown operations;
during other circumstances that could affect the proper functioning of the systems (e.g. regular and extraordinary maintenance work and cleaning operations of the units and/or of the waste gas treatment system);
in case of insufficient waste gas flow or temperature which prevents the use of the waste gas treatment system at full capacity.
BAT 8.In order to prevent and reduce ammonia (NH3) emissions to air when applying selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR) techniques, BAT is to maintain suitable operating conditions of the SCR or SNCR waste gas treatment systems, with the aim of limiting emissions of unreacted NH3.
BAT-associated emission levels: See Table 2.
Table 2
BAT-associated emission levels for ammonia (NH3) emissions to air for a combustion or process unit where SCR or SNCR techniques are used
BAT 9.In order to prevent and reduce emissions to air when using a sour water steam stripping unit, BAT is to route the acid off-gases from this unit to an SRU or any equivalent gas treatment system.
It is not BAT to directly incinerate the untreated sour water stripping gases.
1.1.6.Monitoring of emissions to water
BAT 10.BAT is to monitor emissions to water by using the monitoring techniques with at least the frequency given in Table 3) 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.
1.1.7.Emissions to water
BAT 11.In order to reduce water consumption and the volume of contaminated water, BAT is to use all of the techniques given below.
BAT 12.In order to reduce the emission load of pollutants in the waste water discharge to the receiving water body, BAT is to remove insoluble and soluble polluting substances by using all of the techniques given below.
BAT-associated emission levels: See Table 3.
BAT 13.When further removal of organic substances or nitrogen is needed, BAT is to use an additional treatment step as described in Section 1.21.2.
Table 3
BAT-associated emission levels for direct waste water discharges from the refining of mineral oil and gas and monitoring frequencies associated with BATa
a Not all parameters and sampling frequencies are applicable to effluent from gas refining sites. | |||
b Refers to a flow-proportional composite sample taken over a period of 24 hours or, provided that sufficient flow stability is demonstrated, a time-proportional sample. | |||
c Moving from the current method to EN 9377-2 may require an adaptation period. | |||
d Where on-site correlation is available, COD may be replaced by TOC. The correlation between COD and TOC should be elaborated on a case-by-case basis. TOC monitoring would be the preferred option because it does not rely on the use of very toxic compounds. | |||
e Where total-nitrogen is the sum of total Kjeldahl nitrogen (TKN), nitrates and nitrites. | |||
f When nitrification/denitrification is used, levels below 15 mg/l can be achieved. | |||
| Parameter | Unit | BAT-AEL(yearly average) | Monitoringb frequency and analytical method (standard) |
|---|---|---|---|
| Hydrocarbon oil index (HOI) | mg/l | 0,1-2,5 | Daily EN 9377- 2c |
| Total suspended solids (TSS) | mg/l | 5-25 | Daily |
| Chemical oxygen demand (COD)d | mg/l | 30-125 | Daily |
| BOD5 | mg/l | No BAT-AEL | Weekly |
| Total nitrogene, expressed as N | mg/l | 1-25f | Daily |
| Lead, expressed as Pb | mg/l | 0,005-0,030 | Quarterly |
| Cadmium, expressed as Cd | mg/l | 0,002-0,008 | Quarterly |
| Nickel, expressed as Ni | mg/l | 0,005-0,100 | Quarterly |
| Mercury, expressed as Hg | mg/l | 0,0001-0,001 | Quarterly |
| Vanadium | mg/l | No BAT-AEL | Quarterly |
| Phenol Index | mg/l | No BAT-AEL | Monthly EN 14402 |
| Benzene, toluene, ethyl benzene, xylene (BTEX) | mg/l | Benzene: 0,001-0,050 No BAT-AEL for T, E, X | Monthly |
1.1.8.Waste generation and management
BAT 14.In order to prevent or, where that is not practicable, to reduce waste generation, BAT is to adopt and implement a waste management plan that, in order of priority, ensures that waste is prepared for reuse, recycling, recovery or disposal.
BAT 15.In order to reduce the amount of sludge to be treated or disposed of, BAT is to use one or a combination of the techniques given below.
BAT 16.In order to reduce the generation of spent solid catalyst waste, BAT is to use one or a combination of the techniques given below.
1.1.9.Noise
BAT 17.In order to prevent or reduce noise, BAT is to use one or a combination of the techniques given below:
make an environmental noise assessment and formulate a noise management plan as appropriate to the local environment;
enclose noisy equipment/operation in a separate structure/unit;
use embankments to screen the source of noise;
use noise protection walls.
1.1.10.BAT conclusions for integrated refinery management
BAT 18.In order to prevent or reduce diffuse VOC emissions, BAT is to apply the techniques given below.
1.2.BAT conclusions for the alkylation process
1.2.1.Hydrofluoric acid alkylation process
BAT 19.In order to prevent hydrofluoric acid (HF) emissions to air from the hydrofluoric acid alkylation process, BAT is to use wet scrubbing with alkaline solution to treat incondensable gas streams prior to venting to flare.
Description
See Section 1.20.3.
Applicability:
The technique is generally applicable. Safety requirements, due to the hazardous nature of hydrofluoric acid, are to be considered
BAT 20.In order to reduce emissions to water from the hydrofluoric acid alkylation process, BAT is to use a combination of the techniques given below.
1.2.2.Sulphuric acid alkylation process
BAT 21.In order to reduce the emissions to water from the sulphuric acid alkylation process, BAT is to reduce the use of sulphuric acid by regenerating the spent acid and to neutralise the waste water generated by this process before routing to waste water treatment.
1.3.BAT conclusions for base oil production processes
BAT 22.In order to prevent and reduce the emissions of hazardous substances to air and water from base oil production processes, BAT is to use one or a combination of the techniques given below.
1.4.BAT conclusions for the bitumen production process
BAT 23.In order to prevent and reduce emissions to air from the bitumen production process, BAT is to treat the gaseous overhead by using one of the techniques given below.
1.5.BAT conclusions for the fluid catalytic cracking process
BAT 24.In order to prevent or reduce NOX emissions to air from the catalytic cracking process (regenerator), BAT is to use one or a combination of the techniques given below.
I.Primary or process-related techniques, such as:
II.Secondary or end-of-pipe techniques, such as:
BAT-associated emission levels: See Table 4.
Table 4
BAT-associated emission levels for NOX emissions to air from the regenerator in the catalytic cracking process
a When antimony (Sb) injection is used for metal passivation, NOX levels up to 700 mg/Nm3 may occur. The lower end of the range can be achieved by using the SCR technique. | ||
| Parameter | Type of unit/combustion mode | BAT-AEL(monthly average)mg/Nm3 |
|---|---|---|
| NOX, expressed as NO2 | New unit/all combustion mode | < 30-100 |
| Existing unit/full combustion mode | < 100-300a | |
| Existing unit/partial combustion mode | 100-400a | |
The associated monitoring is in BAT 4.
BAT 25.In order to reduce dust and metals emissions to air from the catalytic cracking process (regenerator), BAT is to use one or a combination of the techniques given below.
I.Primary or process-related techniques, such as:
II.Secondary or end-of-pipe techniques, such as:
BAT-associated emission levels: See Table 5.
Table 5
BAT-associated emission levels for dust emissions to air from the regenerator in the catalytic cracking process
The associated monitoring is in BAT 4.
BAT 26.In order to prevent or reduce SOX emissions to air from the catalytic cracking process (regenerator), BAT is to use one or a combination of the techniques given below.
I.Primary or process-related techniques, such as:
II.Secondary or end-of-pipe techniques, such as:
BAT-associated emission levels: See Table 6.
Table 6
BAT-associated emission levels for SO2 emissions to air from the regenerator in the catalytic cracking process
a Where selection of low sulphur (e.g. < 0,5 % w/w) feed (or hydrotreatment) and/or scrubbing is applicable, for all combustion modes: the upper end of the BAT-AEL range is ≤ 600 mg/Nm3. | ||
| Parameter | Type of units/mode | BAT-AEL(monthly average)mg/Nm3 |
|---|---|---|
| SO2 | New units | ≤ 300 |
| Existing units/full combustion | < 100-800a | |
| Existing units/partial combustion | 100-1 200a | |
The associated monitoring is in BAT 4.
BAT 27.In order to reduce carbon monoxide (CO) emissions to air from the catalytic cracking process (regenerator), BAT is to use one or a combination of the techniques given below.
BAT-associated emission levels: See Table 7.
Table 7
BAT-associated emission levels for carbon monoxide emissions to air from the regenerator in the catalytic cracking process for partial combustion mode
a May not be achievable when not operating the CO boiler at full load. | ||
| Parameter | Combustion mode | BAT-AEL(monthly average)mg/Nm3 |
|---|---|---|
| Carbon monoxide, expressed as CO | Partial combustion mode | ≤ 100a |
The associated monitoring is in BAT 4.
1.6.BAT conclusions for the catalytic reforming process
BAT 28.In order to reduce emissions of polychlorinated dibenzodioxins/furans (PCDD/F) to air from the catalytic reforming unit, BAT is to use one or a combination of the techniques given below.
1.7.BAT conclusions for the coking processes
BAT 29.In order to reduce emissions to air from the coking production processes, BAT is to use one or a combination of the techniques given below:
Primary or process-related techniques, such as:
BAT 30.In order to reduce NOX emissions to air from the calcining of green coke process, BAT is to use selective non-catalytic reduction (SNCR).
Description
See Section 1.20.2.
Applicability
The applicability of the SNCR technique (especially with respect to residence time and temperature window) may be restricted due to the specificity of the calcining process.
BAT 31.In order to reduce SOX emissions to air from the calcining of green coke process, BAT is to use one or a combination of the techniques given below.
BAT 32.In order to reduce dust emissions to air from the calcining of green coke process, BAT is to use a combination of the techniques given below.
BAT-associated emission levels: See Table 8
Table 8
BAT-associated emission levels for dust emissions to air from a unit for the calcining of green coke
The associated monitoring is in BAT 4.
1.8.BAT conclusions for the desalting process
BAT 33.In order to reduce water consumption and emissions to water from the desalting process, BAT is to use one or a combination of the techniques given below.
1.9.BAT conclusions for the combustion units
BAT 34.In order to prevent or reduce NOX emissions to air from the combustion units, BAT is to use one or a combination of the techniques given below.
I.Primary or process-related techniques, such as:
II.Secondary or end-of-pipe techniques, such as:
BAT-associated emission levels: See Table 9, Table 10 and Table 11.
Table 9
BAT-associated emission levels for NOX emissions to air from a gas turbine
a BAT-AEL refers to combined emissions from the gas turbine and the supplementary firing recovery boiler, where present. | ||
b For fuel with high H2 content (i.e. above 10 %), the upper end of the range is 75 mg/Nm3. | ||
| Parameter | Type of equipment | BAT-AELa(monthly average)mg/Nm3 at 15 % O2 |
|---|---|---|
| NOX expressed as NO2 | Gas turbine (including combined cycle gas turbine — CCGT) and integrated gasification combined cycle turbine (IGCC)) | 40-120 (existing turbine) |
20-50 (new turbine)b | ||
The associated monitoring is in BAT 4.
Table 10
BAT-associated emission levels for NOX emissions to air from a gas-fired combustion unit, with the exception of gas turbines
a For an existing unit using high air pre-heat (i.e. > 200 °C) or with H2 content in the fuel gas higher than 50 %, the upper end of the BAT-AEL range is 200 mg/Nm3. | ||
| Parameter | Type of combustion | BAT-AEL(monthly average)mg/Nm3 |
|---|---|---|
| NOX expressed as NO2 | Gas firing | 30-150 for existing unita |
30-100 for new unit | ||
The associated monitoring is in BAT 4.
Table 11
BAT-associated emission levels for NOX emissions to air from a multi-fuel fired combustion unit with the exception of gas turbines
a For existing units < 100 MW firing fuel oil with a nitrogen content higher than 0,5 % (w/w) or with liquid firing > 50 % or using air preheating, values up to 450 mg/Nm3 may occur. | ||
b The lower end of the range can be achieved by using the SCR technique. | ||
| Parameter | Type of combustion | BAT-AEL(monthly average)mg/Nm3 |
|---|---|---|
| NOX expressed as NO2 | Multi-fuel fired combustion unit | 30-300 |
The associated monitoring is in BAT 4.
BAT 35.In order to prevent or reduce dust and metal emissions to air from the combustion units, BAT is to use one or a combination of the techniques given below.
I.Primary or process-related techniques, such as:
II.Secondary or end-of-pipe techniques, such as:
BAT-associated emission levels: See Table 12.
Table 12
BAT-associated emission levels for dust emissions to air from a multi-fuel fired combustion unit with the exception of gas turbines
a The lower end of the range is achievable for units with the use of end-of-pipe techniques. | ||
b The upper end of the range refers to the use of a high percentage of oil burning and where only primary techniques are applicable. | ||
| Parameter | Type of combustion | BAT-AEL(monthly average)mg/Nm3 |
|---|---|---|
| Dust | Multi-fuel firing | 5-50 |
5-25 for new unit < 50 MW | ||
The associated monitoring is in BAT 4.
BAT 36.In order to prevent or reduce SOX emissions to air from the combustion units, BAT is to use one or a combination of the techniques given below.
I.Primary or process-related techniques based on a selection or a treatment of the fuel, such as:
II.Secondary or end-of-pipe techniques:
BAT-associated emission levels: See Table 13 and Table 14.
Table 13
BAT-associated emission levels for SO2 emissions to air from a combustion unit firing refinery fuel gas (RFG), with the exception of gas turbines
a In the specific configuration of RFG treatment with a low scrubber operative pressure and with a refinery fuel gas with an H/C molar ratio above 5, the upper end of the BAT-AEL range can be as high as 45 mg/Nm3. | |
| Parameter | BAT-AEL(monthly average)mg/Nm3 |
|---|---|
| SO2 | 5-35a |
The associated monitoring is in BAT 4.
Table 14
BAT-associated emission levels for SO2 emissions to air from multi-fuel fired combustion units, with the exception of gas turbines and stationary gas engines
This BAT-AEL refers to the weighted average emissions from existing multi-fuel fired combustion units within the refinery, with the exception of gas turbines and stationary gas engines.
| Parameter | BAT-AEL(monthly average)mg/Nm3 |
|---|---|
| SO2 | 35-600 |
The associated monitoring is in BAT 4.
BAT 37.In order to reduce carbon monoxide (CO) emissions to air from the combustion units, BAT is to use a combustion operation control.
Description
See Section 1.20.5.
BAT-associated emission levels: See Table 15.
Table 15
BAT-associated emission levels for carbon monoxide emissions to air from a combustion unit
| Parameter | BAT-AEL(monthly average)mg/Nm3 |
|---|---|
| Carbon monoxide, expressed as CO | ≤ 100 |
The associated monitoring is in BAT 4.
1.10.BAT conclusions for the etherification process
BAT 38.In order to reduce emissions to air from the etherification process, BAT is to ensure the appropriate treatment of process off-gases by routing them to the refinery fuel gas system.
BAT 39.In order to prevent upset of the biotreatment, BAT is to use a storage tank and an appropriate unit production plan management to control the toxic components dissolved content (e.g. methanol, formic acid, ethers) of the waste water stream prior to final treatment.
1.11.BAT conclusions for the isomerisation process
BAT 40.In order to reduce emissions to air of chlorinated compounds, BAT is to optimise the use of chlorinated organic compounds used to maintain catalyst activity when such a process is in place or to use non-chlorinated catalytic systems.
1.12.BAT conclusions for the natural gas refinery
BAT 41.In order to reduce sulphur dioxide emissions to air from the natural gas plant, BAT is to apply BAT 54.
BAT 42.In order to reduce nitrogen oxides (NOX) emissions to air from the natural gas plant, BAT is to apply BAT 34
BAT 43.In order to prevent emissions of mercury when present in raw natural gas, BAT is to remove the mercury and recover the mercury-containing sludge for waste disposal.
1.13.BAT conclusions for the distillation process
BAT 44.In order to prevent or reduce waste water flow generation from the distillation process, BAT is to use liquid ring vacuum pumps or surface condensers.
Applicability
May not be applicable in some retrofit cases. For new units, vacuum pumps, either in or not in combination with steam ejectors, may be needed to achieve a high vacuum (10 mm Hg). Also, a spare should be available in case the vacuum pump fails.
BAT 45.In order to prevent or reduce water pollution from the distillation process, BAT is to route sour water to the stripping unit.
BAT 46.In order to prevent or reduce emissions to air from distillation units, BAT is to ensure the appropriate treatment of process off-gases, especially incondensable off-gases, by acid gas removal prior to further use.
Applicability
Generally applicable for crude and vacuum distillation units. May not be applicable for stand-alone lubricant and bitumen refineries with emissions of less than 1 t/d of sulphur compounds. In specific refinery configurations, applicability may be restricted, due to the need for e.g. large piping, compressors or additional amine treating capacity.
1.14.BAT conclusions for the products treatment process
BAT 47.In order to reduce emissions to air from the products treatment process, BAT is to ensure the appropriate disposal of off-gases, especially odorous spent air from sweetening units, by routing them to destruction, e.g. by incineration.
Applicability
Generally applicable to products treatment processes where the gas streams can be safely processed to the destruction units. May not be applicable to sweetening units, due to safety reasons.
BAT 48.In order to reduce waste and waste water generation when a products treatment process using caustic is in place, BAT is to use cascading caustic solution and a global management of spent caustic, including recycling after appropriate treatment, e.g. by stripping.
1.15.BAT conclusions for storage and handling processes
BAT 49.In order to reduce VOC emissions to air from the storage of volatile liquid hydrocarbon compounds, BAT is to use floating roof storage tanks equipped with high efficiency seals or a fixed roof tank connected to a vapour recovery system.
Description
High efficiency seals are specific devices for limiting losses of vapour, e.g. improved primary seals, additional multiple (secondary or tertiary) seals (according to quantity emitted).
Applicability
The applicability of high efficiency seals may be restricted for retrofitting tertiary seals in existing tanks.
BAT 50.In order to reduce VOC emissions to air from the storage of volatile liquid hydrocarbon compounds, BAT is to use one or a combination of the techniques given below.
BAT 51.In order to prevent or reduce emissions to soil and groundwater from the storage of liquid hydrocarbon compounds, BAT is to use one or a combination of the techniques given below.
a Techniques ii and iii may not be generally applicable where tanks are dedicated to products that require heat for liquid handling (e.g. bitumen), and where no leak is likely because of solidification. | ||
| Technique | Description | Applicability |
|---|---|---|
(i) Maintenance programme including corrosion monitoring, prevention and control | A management system including leak detection and operational controls to prevent overfilling, inventory control and risk-based inspection procedures on tanks at intervals to prove their integrity, and maintenance to improve tank containment. It also includes a system response to spill consequences to act before spills can reach the groundwater. To be especially reinforced during maintenance periods | Generally applicable |
(ii) Double bottomed tanks | A second impervious bottom that provides a measure of protection against releases from the first material | Generally applicable for new tanks and after overhaul of existing tanksa |
(iii) Impervious membrane liners | A continuous leak barrier under the entire bottom surface of the tank | Generally applicable for new tanks and after an overhaul of existing tanksa |
(iv) Sufficient tank farm bund containment | A tank farm bund is designed to contain large spills potentially caused by a shell rupture or overfilling (for both environmental and safety reasons). Size and associated building rules are generally defined by local regulations | Generally applicable |
BAT 52.In order to prevent or reduce VOC emissions to air from loading and unloading operations of volatile liquid hydrocarbon compounds, BAT is to use one or a combination of the techniques given below to achieve a recovery rate of at least 95 %.
a A vapour destruction unit (e.g. by incineration) may be substituted for a vapour recovery unit, if vapour recovery is unsafe or technically impossible because of the volume of return vapour. | ||
| Technique | Description | Applicabilitya |
|---|---|---|
Vapour recovery by: (i) Condensation (ii) Absorption (iii) Adsorption (iv) Membrane separation (v) Hybrid systems | See Section 1.20.6 | Generally applicable to loading/unloading operations where annual throughput is > 5 000 m3/yr. Not applicable to loading/unloading operations for sea-going vessels with an annual throughput < 1 million m3/yr |
BAT-associated emission levels: See Table 16.
Table 16
BAT-associated emission levels for non-methane VOC and benzene emissions to air from loading and unloading operations of volatile liquid hydrocarbon compounds
a Hourly values in continuous operation expressed and measured according to European Parliament and Council Directive 94/63/EC (OJ L 365, 31.12.1994, p. 24). | |
b Lower value achievable with two-stage hybrid systems. Upper value achievable with single-stage adsorption or membrane system. | |
c Benzene monitoring may not be necessary where emissions of NMVOC are at the lower end of the range. | |
| Parameter | BAT-AEL(hourly average)a |
|---|---|
| NMVOC | 0,15-10 g/Nm3bc |
| Benzenec | < 1 mg/Nm3 |
1.16.BAT conclusions for visbreaking and other thermal processes
BAT 53.In order to reduce emissions to water from visbreaking and other thermal processes, BAT is to ensure the appropriate treatment of waste water streams by applying the techniques of BAT 11.
1.17.BAT conclusions for waste gas sulphur treatment
BAT 54.In order to reduce sulphur emissions to air from off-gases containing hydrogen sulphides (H2S), BAT is to use all of the techniques given below.
a May not be applicable for stand-alone lubricant or bitumen refineries with a release of sulphur compounds of less than 1 t/d | ||
| Technique | Description | Applicabilitya |
|---|---|---|
(i) Acid gas removal e.g. by amine treating | See Section 1.20.3 | Generally applicable |
(ii) Sulphur recovery unit (SRU), e.g. by Claus process | See Section 1.20.3 | Generally applicable |
(iii) Tail gas treatment unit (TGTU) | See Section 1.20.3 | For retrofitting existing SRU, the applicability may be limited by the SRU size and configuration of the units and the type of sulphur recovery process already in place |
BAT-associated environmental performance levels (BAT-AEPL): See Table 17.
Table 17
BAT-associated environmental performance levels for a waste gas sulphur (H2S) recovery system
a Sulphur recovery efficiency is calculated over the whole treatment chain (including SRU and TGTU) as the fraction of sulphur in the feed that is recovered in the sulphur stream routed to the collection pits. When the applied technique does not include a recovery of sulphur (e.g. seawater scrubber), it refers to the sulphur removal efficiency, as the % of sulphur removed by the whole treatment chain. | |
| BAT-associated environmental performance level (monthly average) | |
|---|---|
| Acid gas removal | Achieve hydrogen sulphides (H2S) removal in the treated RFG in order to meet gas firing BAT-AEL for BAT 36 |
| Sulphur recovery efficiencya | New unit: 99,5 – > 99,9 % |
| Existing unit: ≥ 98,5 % | |
The associated monitoring is described in BAT 4.
1.18.BAT conclusions for flares
BAT 55.In order to prevent emissions to air from flares, BAT is to use flaring only for safety reasons or for non-routine operational conditions (e.g. start-ups, shutdown).
BAT 56.In order to reduce emissions to air from flares when flaring is unavoidable, BAT is to use the techniques given below.
1.19.BAT conclusions for integrated emission management
BAT 57.In order to achieve an overall reduction of NOX emissions to air from combustion units and fluid catalytic cracking (FCC) units, BAT is to use an integrated emission management technique as an alternative to applying BAT 24 and BAT 34.
Description
The technique consists of managing NOX emissions from several or all combustion units and FCC units on a refinery site in an integrated manner, by implementing and operating the most appropriate combination of BAT across the different units concerned and monitoring the effectiveness thereof, in such a way that the resulting total emissions are equal to or lower than the emissions that would be achieved through a unit-by-unit application of the BAT-AELs referred to in BAT 24 and BAT 34.
This technique is especially suitable to oil refining sites:
with a recognised site complexity, multiplicity of combustion and process units interlinked in terms of their feedstock and energy supply;
with frequent process adjustments required in function of the quality of the crude received;
with a technical necessity to use a part of process residues as internal fuels, causing frequent adjustments of the fuel mix according to process requirements.
BAT-associated emission levels: See Table 18.
In addition, for each new combustion unit or new FCC unit included in the integrated emission management system, the BAT-AELs set out under BAT 24 and BAT 34 remain applicable.
Table 18BAT-associated emission levels for NOx emissions to air when applying BAT 57
The BAT-AEL for NOx emissions from the units concerned by BAT 57, expressed in mg/Nm3 as a monthly average value, is equal to or less than the weighted average of the NOx concentrations (expressed in mg/Nm3 as a monthly average) that would be achieved by applying in practice at each of those units techniques that would enable the units concerned to meet the following:
for catalytic cracking process (regenerator) units: the BAT-AEL range set out in Table 4 (BAT 24);
for combustion units burning refinery fuels alone or simultaneously with other fuels: the BAT-AEL ranges set out in Tables 9, 10 and 11 (BAT 34).
This BAT-AEL is expressed by the following formula:
Notes:
1.The applicable reference conditions for oxygen are those specified in Table 1.
2.The weighing of the emission levels of the individual units is done on the basis of the flue-gas flow rate of the unit concerned, expressed as a monthly average value (Nm3/hour), which is representative for the normal operation of that unit within the refinery installation (applying the reference conditions under Note 1).
3.In case of substantial and structural fuel changes which are affecting the applicable BAT-AEL for a unit or other substantial and structural changes in the nature or functioning of the units concerned, or in case of their replacement or extension or the addition of combustion units or FCC units, the BAT-AEL defined in Table 18 needs to be adjusted accordingly.
Monitoring associated with BAT 57
BAT for monitoring emissions of NOx under an integrated emission management technique is as in BAT 4, complemented with the following:
a monitoring plan including a description of the processes monitored, a list of the emission sources and source streams (products, waste gases) monitored for each process and a description of the methodology (calculations, measurements) used and the underlying assumptions and associated level of confidence;
continuous monitoring of the flue-gas flow rates of the units concerned, either through direct measurement or by an equivalent method;
a data management system for collecting, processing and reporting all monitoring data needed to determine the emissions from the sources covered by the integrated emission management technique.
BAT 58.In order to achieve an overall reduction of SO2 emissions to air from combustion units, fluid catalytic cracking (FCC) units and waste gas sulphur recovery units, BAT is to use an integrated emission management technique as an alternative to applying BAT 26, BAT 36 and BAT 54.
Description
The technique consists of managing SO2 emissions from several or all combustion units, FCC units and waste gas sulphur recovery units on a refinery site in an integrated manner, by implementing and operating the most appropriate combination of BAT across the different units concerned and monitoring the effectiveness thereof, in such a way that the resulting total emissions are equal to or lower than the emissions that would be achieved through a unit-by-unit application of the BAT-AELs referred to in BAT 26 and BAT 36 as well as the BAT-AEPL set out under BAT 54.
This technique is especially suitable to oil refining sites:
with a recognised site complexity, multiplicity of combustion and process units interlinked in terms of their feedstock and energy supply;
with frequent process adjustments required in function of the quality of the crude received;
with a technical necessity to use a part of process residues as internal fuels, causing frequent adjustments of the fuel mix according to process requirements.
BAT associated emission level: See Table 19.
In addition, for each new combustion unit, new FCC unit or new waste gas sulphur recovery unit included in the integrated emission management system, the BAT-AELs set out under BAT 26 and BAT 36 and the BAT-AEPL set out under BAT 54 remain applicable.
Table 19BAT-associated emission levels for SO2 emissions to air when applying BAT 58
The BAT-AEL for SO2 emissions from the units concerned by BAT 58, expressed in mg/Nm3 as a monthly average value, is equal to or less than the weighted average of the SO2 concentrations (expressed in mg/Nm3 as a monthly average) that would be achieved by applying in practice at each of those units techniques that would enable the units concerned to meet the following:
for catalytic cracking process (regenerator) units: the BAT-AEL ranges set out in Table 6 (BAT 26);
for combustion units burning refinery fuels alone or simultaneously with other fuels: the BAT-AEL ranges set out in Table 13 and in Table 14 (BAT 36); and
for waste gas sulphur recovery units: the BAT-AEPL ranges set out in Table 17 (BAT 54).
This BAT-AEL is expressed by the following formula:
Notes:
1.The applicable reference conditions for oxygen are those specified in Table 1.
2.The weighing of the emission levels of the individual units is done on the basis of the flue-gas flow rate of the unit concerned, expressed as the monthly average value (Nm3/hour), which is representative for the normal operation of that unit within the refinery installation (applying the reference conditions under Note 1).
3.In case of substantial and structural fuel changes which are affecting the applicable BAT-AEL for a unit or other substantial and structural changes in the nature or functioning of the units concerned, or in case of their replacement, extension or the addition of combustion, FCC, or waste gas sulphur recovery units, the BAT-AEL defined in Table 19 needs to be adjusted accordingly.
Monitoring associated with BAT 58
BAT for monitoring emissions of SO2 under an integrated emission management approach is as in BAT 4, complemented with the following:
a monitoring plan including a description of the processes monitored, a list of the emission sources and source streams (products, waste gases) monitored for each process and a description of the methodology (calculations, measurements) used and the underlying assumptions and associated level of confidence;
continuous monitoring of the flue-gas flow rates of the units concerned, either through direct measurement or by an equivalent method;
a data management system for collecting, processing and reporting all monitoring data needed to determine the emissions from the sources covered by the integrated emission management technique.
GLOSSARY
1.20.Description of techniques for the prevention and control of emissions to air
1.20.1.Dust
| Technique | Description |
|---|---|
| Electrostatic precipitator (ESP) | Electrostatic precipitators operate such that particles are charged and separated under the influence of an electrical field. Electrostatic precipitators are capable of operating under a wide range of conditions. Abatement efficiency may depend on the number of fields, residence time (size), catalyst properties and upstream particles removal devices. At FCC units, 3-field ESPs and 4-field ESPs are commonly used. ESPs may be used on a dry mode or with ammonia injection to improve the particle collection. For the calcining of green coke, the ESP capture efficiency may be reduced due to the difficulty for coke particles to be electrically charged |
| Multistage cyclone separators | Cyclonic collection device or system installed following the two stages of cyclones. Generally known as a third stage separator, common configuration consists of a single vessel containing many conventional cyclones or improved swirl-tube technology. For FCC, performance mainly depends on the particle concentration and size distribution of the catalyst fines downstream of the regenerator internal cyclones |
| Centrifugal washers | Centrifugal washers combine the cyclone principle and an intensive contact with water e.g. venturi washer |
| Third stage blowback filter | Reverse flow (blowback) ceramic or sintered metal filters where, after retention at the surface as a cake, the solids are dislodged by initiating a reverse flow. The dislodged solids are then purged from the filter system |
1.20.2.Nitrogen oxides (NOX)
| Technique | Description |
|---|---|
| Combustion modifications | |
| Staged combustion |
|
| Flue-gas recirculation | Reinjection of waste gas from the furnace into the flame to reduce the oxygen content and therefore the temperature of the flame. Special burners using the internal recirculation of combustion gases to cool the root of the flames and reduce the oxygen content in the hottest part of the flames |
| Use of low-NOX burners (LNB) | The technique (including ultra-low-NOX burners) 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 combustion staging (air/fuel) and flue-gas recirculation. Dry low-NOX burners (DLNB) are used for gas turbines |
| Optimisation of combustion | Based on permanent monitoring of appropriate combustion parameters (e.g. O2, CO content, fuel to air (or oxygen) ratio, unburnt components), the technique uses control technology for achieving the best combustion conditions |
| Diluent injection | Inert diluents, e.g. flue-gas, steam, water, nitrogen added to combustion equipment reduce the flame temperature and consequently the concentration of NOX in the flue-gases |
| Selective catalytic reduction (SCR) | The technique is based on the reduction of NOX to nitrogen in a catalytic bed by reaction with ammonia (in general aqueous solution) at an optimum operating temperature of around 300-450 °C. One or two layers of catalyst may be applied. A higher NOX reduction is achieved with the use of higher amounts of catalyst (two layers) |
| Selective non-catalytic reduction (SNCR) | The technique is based on 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 for optimal reaction |
| Low temperature NOX oxidation | The low temperature oxidation process injects ozone into a flue-gas stream at optimal temperatures below 150 °C, to oxidise insoluble NO and NO2 to highly soluble N2O5. The N2O5 is removed in a wet scrubber by forming dilute nitric acid waste water that can be used in plant processes or neutralised for release and may need additional nitrogen removal |
1.20.3.Sulphur oxides (SOX)
| Technique | Description |
|---|---|
| Treatment of refinery fuel gas (RFG) | Some refinery fuel gases may be sulphur-free at source (e.g. from catalytic reforming and isomerisation processes) but most other processes produce sulphur-containing gases (e.g. off-gases from the visbreaker, hydrotreater or catalytic cracking units). These gas streams require an appropriate treatment for gas desulphurisation (e.g. by acid gas removal — see below — to remove H2S) before being released to the refinery fuel gas system |
| Refinery fuel oil (RFO) desulphurisation by hydrotreatment | In addition to selection of low-sulphur crude, fuel desulphurisation is achieved by the hydrotreatment process (see below) where hydrogenation reactions take place and lead to a reduction in sulphur content |
| Use of gas to replace liquid fuel | Decrease the use of liquid refinery fuel (generally heavy fuel oil containing sulphur, nitrogen, metals, etc.) by replacing it with on-site Liquefied Petroleum Gas (LPG) or refinery fuel gas (RFG) or by externally supplied gaseous fuel (e.g. natural gas) with a low level of sulphur and other undesirable substances. At the individual combustion unit level, under multi-fuel firing, a minimum level of liquid firing is necessary to ensure flame stability |
| Use of SOX reducing catalysts additives | Use of a substance (e.g. metallic oxides catalyst) that transfers the sulphur associated with coke from the regenerator back to the reactor. It operates most efficiently in full combustion mode rather than in deep partial-combustion mode. NB: SOX reducing catalysts additives might have a detrimental effect on dust emissions by increasing catalyst losses due to attrition, and on NOX emissions by participating in CO promotion, together with the oxidation of SO2 to SO3 |
| Hydrotreatment | Based on hydrogenation reactions, hydrotreatment aims mainly at producing low-sulphur fuels (e.g. 10 ppm gasoline and diesel) and optimising the process configuration (heavy residue conversion and middle distillate production). It reduces the sulphur, nitrogen and metal content of the feed. As hydrogen is required, sufficient production capacity is needed. As the technique transfer sulphur from the feed to hydrogen sulphide (H2S) in the process gas, treatment capacity (e.g. amine and Claus units) is also a possible bottleneck |
| Acid gas removal e.g. by amine treating | Separation of acid gas (mainly hydrogen sulphide) from the fuel gases by dissolving it in a chemical solvent (absorption). The commonly used solvents are amines. This is generally the first step treatment needed before elemental sulphur can be recovered in the SRU |
| Sulphur recovery unit (SRU) | Specific unit that generally consists of a Claus process for sulphur removal of hydrogen sulphide (H2S)-rich gas streams from amine treating units and sour water strippers. SRU is generally followed by a tail gas treatment unit (TGTU) for remaining H2S removal |
| Tail gas treatment unit (TGTU) | A family of techniques, additional to the SRU in order to enhance the removal of sulphur compounds. They can be divided into four categories according to the principles applied:
|
| Wet scrubbing | In the wet scrubbing process, gaseous compounds are dissolved in a suitable liquid (water or alkaline solution). Simultaneous removal of solid and gaseous compounds may be achieved. Downstream of the wet scrubber, the flue-gases are saturated with water and a separation of the droplets is required before discharging the flue-gases. The resulting liquid has to be treated by a waste water process and the insoluble matter is collected by sedimentation or filtration According to the type of scrubbing solution, it can be:
According to the contact method, the various techniques may require e.g.:
Where scrubbers are mainly intended for SOX removal, a suitable design is needed to also efficiently remove dust. The typical indicative SOx removal efficiency is in the range 85-98 %. |
| Non-regenerative scrubbing | Sodium or magnesium-based solution is used as alkaline reagent to absorb SOX generally as sulphates. Techniques are based on e.g.:
|
| Seawater scrubbing | A specific type of non-regenerative scrubbing using the alkalinity of the seawater as solvent. Generally requires an upstream abatement of dust |
| Regenerative scrubbing | Use of specific SOX absorbing reagent (e.g. absorbing solution) that generally enables the recovery of sulphur as a by-product during a regenerating cycle where the reagent is reused |
1.20.4.Combined techniques (SOx, NOx and dust)
| Technique | Description |
|---|---|
| Wet scrubbing | See Section 1.20.3 |
| SNOX combined technique | Combined technique to remove SOX, NOX and dust where a first dust removal stage (ESP) takes place followed by some specific catalytic processes. The sulphur compounds are recovered as commercial-grade concentrated sulphuric acid, while NOX is reduced to N2. Overall SOX removal is in the range: 94-96,6 %. Overall NOX removal is in the range: 87-90 % |
1.20.5.Carbon monoxide (CO)
| Technique | Description |
|---|---|
| Combustion operation control | The increase in CO emissions due to the application of combustion modifications (primary techniques) for the reduction of NOX emissions can be limited by a careful control of the operational parameters |
| Catalysts with carbon monoxide (CO) oxidation promoters | Use of a substance which selectively promotes the oxidation of CO into CO2 (combustion) |
| Carbon monoxide (CO) boiler | Specific post-combustion device where CO present in the flue-gas is consumed downstream of the catalyst regenerator to recover the energy It is usually used only with partial-combustion FCC units |
1.20.6.Volatile organic compounds (VOC)
1.20.7.Other techniques
| Technique | Description |
|---|---|
| Techniques to prevent or reduce emissions from flaring | Correct plant design : includes sufficient flare gas recovery system capacity, the use of high-integrity relief valves and other measures to use flaring only as a safety system for other than normal operations (start-up, shutdown, emergency). Plant management : includes organisational and control measures to reduce flaring events by balancing RFG system, using advanced process control, etc. Flaring devices design : includes height, pressure, assistance by steam, air or gas, type of flare tips, etc. It aims at enabling smokeless and reliable operations and ensuring an efficient combustion of excess gases when flaring from non-routine operations. Monitoring and reporting : Continuous monitoring (measurements of gas flow and estimations of other parameters) of gas sent to flaring and associated parameters of combustion (e.g. flow gas mixture and heat content, ratio of assistance, velocity, purge gas flow rate, pollutant emissions). Reporting of flaring events makes it possible to use flaring ratio as a requirement included in the EMS and to prevent future events. Visual remote monitoring of the flare can also be carried out by using colour TV monitors during flare events |
| Choice of the catalyst promoter to avoid dioxins formation | During the regeneration of the reformer catalyst, organic chloride is generally needed for effective reforming catalyst performance (to re-establish the proper chloride balance in the catalyst and to assure the correct dispersion of the metals). The choice of the appropriate chlorinated compound will have an influence on the possibility of emissions of dioxins and furans |
| Solvent recovery for base oil production processes | The solvent recovery unit consists of a distillation step where the solvents are recovered from the oil stream and a stripping step (with steam or an inert gas) in a fractionator. The solvents used may be a mixture (DiMe) of 1,2-dichloroethane (DCE) and dichloromethane (DCM). In wax-processing units, solvent recovery (e.g. for DCE) is carried out using two systems: one for the deoiled wax and another one for the soft wax. Both consist of heat-integrated flashdrums and a vacuum stripper. Streams from the dewaxed oil and waxes product are stripped for removal of traces of solvents |
1.21.Description of techniques for the prevention and control of emissions to water
1.21.1.Waste water pretreatment
| Technique | Description |
|---|---|
| Pretreatment of sour water streams before reuse or treatment | Send generated sour water (e.g. from distillation, cracking, coking units) to appropriate pretreatment (e.g. stripper unit) |
| Pretreatment of other waste water streams prior to treatment | To maintain treatment performance, appropriate pretreatment may be required |
1.21.2.Waste water treatment
| Technique | Description |
|---|---|
| Removal of insoluble substances by recovering oil. | These techniques generally include:
|
| Removal of insoluble substances by recovering suspended solid and dispersed oil | These techniques generally include:
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| Removal of soluble substances including biological treatment and clarification | Biological treatment techniques may include:
One of the most commonly used suspended bed system in refineries WWTP is the activated sludge process. Fixed bed systems may include a biofilter or trickling filter |
| Additional treatment step | A specific waste water treatment intended to complement the previous treatment steps e.g. for further reducing nitrogen or carbon compounds. Generally used where specific local requirements for water preservation exist. |