REFINERIES

1. REFINERIES GROUP 6: Blázquez Díaz, Mª Luisa Chasco Aristimuño, Javier Eloy Espejo Gonzalez, Pablo Pereda Mateo, Ignacio

2. INTRODUCTION Petroleum refineries are complex plants, where the combination and sequence of processes is usually very specific to the characteristics of the raw materials (crude oil) and the products to be produced. The European Refinery industry: The mineral oil and gas refinery industry is an important and strategic industry. Mineral oil refineries alone provide 42% of EU energy requirements and 95% of the fuels required for transport. About 100 mineral oil refineries have been identified in EU, Switzerland and Norway and together they process around 700 million tonnes per year. Estimations show that the mineral oil refinery sector has 55000 direct employees and some 35000 indirect employees.

3. INTRODUCTION This figure shows only the main pollutants generated by refineries, but more than 90 specific compounds have been identified. The great majority are pollutants to air.

4. RAW MATERIAL AND ENERGY CONSUMPTION Heat and electricity are needed to run a refinery. The fairly extensive heat requirement is generally satisfied by fuel combustion. Electricity can be generated in the refinery and it can be bought from the grid. Normally, most or all of the gaseous and liquid refinery fuels used are by-products of refinery processes. The composition and quality of these fuels vary with the crude oils processed.

5. RAW MATERIAL CONSUMPTION Water and steam are used in the various refinery processes to assist the distillation process or the cracking of hydrocarbons and in scrubbing, quenching or (steam) stripping. Petroleum refineries use relatively large volumes of water: in the processes; in steam generation and, especially, in cooling systems. The principal raw material input to petroleum refineries is crude oil Coke is burnt in the catalytic cracking regenerator and coking process and represents a heat production source in the refinery. Coal, as imported fuel, is not applied in European refineries. Refinery fuel gas (RFG) The majority of the fuel used in a refinery is gas (methane, ethane and ethylene in combination with excess hydrogen).

6. RAW MATERIAL CONSUMPTION • THE MAIN OPERATIONS: PURPOSE AND PRINCIPLE & FEED AND PRODUCT STREAMS: • Alkylation: The purpose of alkylation is to yield high-quality motor fuel blending Low-molecular weight olefins (C3-C5) and isobutane are used as alkylation unit feedstocks.

7. RAW MATERIAL CONSUMPTION 2. Base oil production: Although only 20 % of EU+ refineries produce base oil. The feedstocks to a conventional base oil complex are waxy distillate side-streams from vacuum distillation units and the extract from deasphalting units. 3. Catalytic cracking: Catalytic cracking is the most widely used conversion process for upgrading heavier hydrocarbons into more valuable lower boiling hydrocarbons. Normally the main feed stream to a catalytic cracking unit (catcracker) is the heavy vacuum distillate stream from the vacuum distillation unit.

8. RAW MATERIAL CONSUMPTION 4. Catalytic reforming: So the purpose of a catalytic reformer is to upgrade these streams for use as a gasoline blendstock. The typical feedstocks to catalytic reformer units are the hydrotreated straight-run heavy naphtha stream from the crude distillation unit and, if applicable, the hydrotreated heavy naphtha stream from the hydrocracker unit and medium catcracked naphtha stream. 5. Coking processes: Coking is a severe thermal cracking process used primarily to reduce refinery production of low-value residual fuel oils and transform it into transportation fuels, such as gasoline and diesel. As the coking process is a thermal destruction process, the quality of the feed in terms of metal content, Concarbon number and other contaminants is not critical. As a matter of fact, coking is predominantly used when the feed has a high Concarbon number and contains high quantities of impurities which cannot be handled in catalytic conversion processes.

9. ENERGY CONSUMPTION The capacity of the combustion plants in a refinery varies widely from less than 10 to up to 200 megawatts thermal input (MWth), and the total installed capacity ranges from several hundred to more than 1500 MWhth in the largest refineries.

10. EMISSIONS • Emissions to the atmosphere: Typically, more than 60 % of refinery air emissions are related to the production of energy for the various processes. The main air emissions from a refinery are CO2, SOx, NOx, VOC and particulates (dust, soot and associated heavy metals (mainly V and Ni)).

11. EMISSIONS

12. EMISSIONS • Particulate emissions: The concern with particulate emissions stems from health effects. The main emission sources are process furnaces/ boilers, catalytic cracker regenerators, coke plants, incinerators, decoking & sootblowing of furnaces and the flare. The range of emissions found in European refineries is from 100 to 20000 tonnes of particulates emitted per year.

13. EMISSIONS • Emissions to water: The main water contaminants are hydrocarbons, sulphides, ammonia and some metals

14. EMISSIONS • Soil and groundwater contamination: The main sources of contamination of soil and groundwater by oil are typically those places along the handling and processing train of crude to products where hydrocarbons can be lost to the ground. These are commonly associated with the storage, transfer, and transport of the hydrocarbons themselves or of hydrocarbon-containing water. The possibility of contamination by other substances such as contaminated water, catalysts and wastes also exists.

15. BEST AVAILABLE TECHNIQUES (BAT) BAT assessment : • Environmental performance is the main criterion used to determine BAT. Moreover, a technique considered to be BAT should have a demonstrated applicability within the refinery sector or in another industrial sector. • A technique considered to be BAT needs to be economically viable within the sector. , it is considered economically viable within the refinery sector if it • has already been applied on a certain number of occasions within the refinery sector or other similar industrial sectors. • Operational data and applicability are criteria considered as limitations for the implementation of BAT in certain circumstances General applicability problems • in the implementation of techniques in existing installations are, for example, space, operational problems…

16. Generic (whole refinery) BAT What is a BAT? They are techniques for continuous improvement of environmental performance. They provide the framework for ensuring the identification, adoption of and adherence to BAT options that, whilst often down-to-earth, are important. These good housekeeping/management techniques/tools often prevent emissions.

17. Purposes of BAT • Implement and adhere to an Environmental Management System • Improve stability of unit operation by applying advanced process control and limiting plant upsets, thereby minimising times with elevated emissions (e.g. shutdowns and startups) • Apply good practices for maintenance and cleaning • Implement environmental awareness and include it in training programmes • Implement a monitoring system that allows adequate processing and emission control. • Improve the energy efficiency (reduction of all air pollutants generated by combustion) by enhancing heat integration and recovery throughout the refinery, applying energy conservation techniques and optimising the energy production/consumption. • Reduce sulphur dioxide emissions. • Reduce nitrogen oxides emissions. • Reduce particulate emission • Reduce volatile organic carbons emissions • Reduce discharges to water

18. BAT for reduce sulphur dioxide emissions • Quantifying the sulphur emissions from various refinery sources to identify the main emitters in each specific case. • Using BAT applicable to SO2 emission reduction in the energy system, catcrackers and cokers • Reducing SO2 emissions from typically small contributors

19. BAT for reduce nitrogen oxides emissions • Quantifying the NOx emission sources in order to identify the main emitters (e.g. furnaces and boilers, the FCC regenerators and gas turbines) in each specific case • Using BAT applicable to NOx reduction in the energy system and catcracker

20. BAT for reduce particulate emission • Quantifying the particulate emission sources (especially furnaces and boilers, the FCC regenerators and cokers) in order to identify the main emitters in each specific case. • Minimising the particulate emissions from solids handling situations (catalyst loading/unloading, coke handling, sludge transport) by applying good housekeeping and control techniques. • Using BAT applicable to particulate reduction in the energy system, catcrackers and cokers

21. BAT for reduce volatile organic carbons emissions • Quantifying VOC emission sources in order to identify the main emitters in each specific case • Using a maintenance drain-out system • Selecting and using low-leakage valves such as graphite-packed valves or equivalent (especially important for control valves) for lines containing product with a high vapour pressure. • Using low leak pumps (e.g. seal-less designs, double seals, with gas seals or good mechanical seals) on product lines carrying fluid with a high vapour pressure • Minimising flanges (easier to apply in the design stage), installing sealing rings on leaking flanges • Blinding, plugging or capping open-ended vent and drain valves • Routing relief valves with high potential VOC emissions to flare • Routing compressor vents with high potential for VOC emissions back to process and when not possible (e.g. vent compressor distance pieces) to refinery flare for destruction • Using totally closed loop in all routine samplers that potentially may generate VOC emissions • Minimising flaring • Using BAT applicable to VOC reduction in storage and handling

22. BAT for reduce discharges to water • apply a water management scheme (as part of the EMS) aimed at reducing: a) the volume of water used in the refinery by: - water stream integration options including water optimisation studies -re-using as much as possible the cleaned waste water -applying techniques to reduce waste water generated within each specific process/activity b) the contamination of water by: - segregation of contaminated, low-contaminated or non-contaminated water streams and, where possible, drainage systems -segregation of “once-through” cooling water from process effluent until after this has been treated -good housekeeping in operation and maintenance of existing facilities -spill prevention and control -applying techniques to reduce contamination of waste water within each specific process/activity

23. EMERGING TECHNIQUES This chapter contains those techniques that may appear in the near future and that may be applicable to the refinery sector. Throughout its history the refining industry has continuously developed new and improved processes in response to changes in feed quality, product specifications, product slates, new product outlets and economic and environmental requirements but These developments have slowed down in recent years for three reasons:

24. EMERGING TECHNIQUES 1. Large oil companies are cutting down on their R&D budgets, and are more and more relying on third parties for new developments in refinery technology and catalytic processes. 2. Technological developments are concentrating on optimising current systems for higher yields, higher energy efficiency and shorter downtimes rather than novel processes. 3. The current tool box of conversion, separation, treatment and environmental technologies seems adequate and sufficient to meet any desired product slate and product specifications for the coming decade as well as meeting stringent regulatory requirements;

25. EMERGING TECHNIQUES • Alkylation: Numerous companies are putting a large R&D effort into the development of a new solid catalyst for the alkylation process. Technology providers claim that these techniques will be ready in the market in one to two years.

26. EMERGING TECHNIQUES • Base oil production: A recently published new technology is the application of membranes for solvent recovery in the solvent extraction/dewaxing processes. Driving force is the reduction in energy consumption. • Energy system: The search for further energy improvements is continuing, with the current focus on attractive cogeneration opportunities and more complex heat integration.

27. EMERGING TECHNIQUES • Catalytic cracking: Some promising lines of investigation for the improvement of the environmental performance of catcrackers are: • the capability to process heavier feedstocks, containing more contaminants such as vanadium and nickel and having a higher Conradson Carbon Residue (CCR) content. Responses that are being developed are: continue the development of more active catalysts and more effective catalyst regeneration. Driving forces are the reduction of residue and higher overall refinery efficiency. • hot ceramic filters can be retrofitted to the underflow of third stage cyclones. • improvement of the catalyst separation by use of a magnet (Kellogg Tech company) • other flue gas desulphurization includes CanSolv’s amine scrubbing system for SO2 removal.

28. EMERGING TECHNIQUES • Hydrogen production: Some promising lines of investigation in hydrogen production technologies are: • the hydrocarb process, in which the residual oil is essentially cracked to carbon and hydrogen. It has been calculated in a refinery of 4.98 t/yr that this process can increase by 40 % the total gasoline production. • methane pyrolysis, which takes advantage of the thermal decomposition of natural gas and the direct production of hydrogen while sequestering the carbon or using the carbon for other commodity purposes. Consequently the CO2 generation is completely eliminated

29. EMERGING TECHNIQUES • Hydrogen-consuming processes: Some promising lines of investigation for the improvement of the environmental performance of energy systems are: • residue hydrotreating and hydroconversion processes (e.g. slurry bed technology). This process has only been demonstrated at semi-commercial scale and no commercial plants are in operation yet. • gasoline deep desulphurization techniques with a lower hydrogen consumption are currently under development. Parameters are not yet available.

30. EMERGING TECHNIQUES • Integrated refinery management: • Leak detection technology: Smart LDAR. This device is able to detect (using laser technology) fugitive hydrocarbon emissions by real time video imaging of the equipment under surveillance. It allows the user to identify at a refinery the zones in which the greatest emissions are located so that an LDAR using sniffing techniques can focus on the high emission items. This technology is under development and a number of technical issues need resolving before it is ready for use as a routine tool.

31. EMERGING TECHNIQUES • Integrated refinery management: 2. Waste gas treatments Some developments to be mentioned are: • sulphur dioxide removal by SO2 capture from flue gas and conversion into liquid sulphur. • biological H2S removal • particulate abatement techniques by new developments including ceramic filters and a rotating particulate separator • CO2 abatement techniques.

32. REFINERIES GROUP 6: Blázquez Díaz, Mª Luisa Chasco Aristimuño, Javier Eloy Espejo Gonzalez, Pablo Pereda Mateo, Ignacio