Major Refining Process Technologies and Options To Meet Future Fuel Specifications

1. Major Refining Process Technologies and Options To Meet Future Fuel Specifications

2. Major Refining Process Technologies Detailed Analysis

3. Product Quality and Policy • A steady evolution in product specifications caused by an endless wave of fresh environmental regulations plays a major role in the development of petroleum refining technologies • India has also put in place Auto Fuel policy prepared by group of experts and accepted by the government of India for the implementation in the country. The policy provides a clear cut road map for changes in vehicular technology and corresponding fuel quality for the whole country. It is estimated that the existing domestic oil refineries in addition to the investment of Rs 10,000 crores already made to achieve Euro stage II / Bharat Stage II auto fuel specifications would need to incur an additional investment of around Rs.18,000 crores by the year 2005. Further investment of around Rs.12,000 crores will need to be made during the period 2005-2010.

4. Constraints Faced by Refiners • Spiraling crude cost • Current refinery configuration not able to meet clean fuels specifications for MS and HSD. • Lower distillate production (production of more bottoms) • Need to produce value added products • Older technologies (High energy consumption) • Environmental issues

5. Road Map for Vehicular Emission Norms

7. Gasoline Specifications

8. Major Changes in specifications • Sulphur Reduction • Benzene Reduction • Aromatics Reduction • Octane Retention • RVP Limitation • Olefins Limitation

9. Sulphur Reduction In gasoline Pool • Main Sulphur contributor in Gasoline pool is FCC Naphtha • Generally reducing ‘S’ in FCC naphtha may enable refinery to meet pool Sulphur specifications

10. FCC Naphtha Treatment Strategies to reduce ‘S’ content of FCC Naphtha may include : • Processing of low Sulphur crudes • End Point reduction of FCC Naphtha • FCC Feed hydrotreating • FCC Naphtha hydro treatment

11. FCC Feed Hydrotreating A large variety of technologies are available for FCC Feed hydro treatment. The benefits of these technologies are: • Reduction in FCC gasoline Sulphur • Improvement in FCC yields with respect to gasoline & LPG • LCGO Sulphur reduction • Lower FCC emissions However, all the technologies require large capital investments, and Hydrogen requirements are also very high.

12. FCC Naphtha Hydrotreating A large variety of technologies are available for FCC Naphtha hydro treatment. However, the main challenge is to retain Octane No. Available technologies are: • Conventional Hydrotreating • Selective Hydrotreating • Non – Selective Hydrotreating combined with Octane Recovery • Developing technologies e.g. Adsorption & selective hydrotreating combined with Sorption

13. FCC Naphtha Hydrotreating • Conventional Hydrotreating Conventional Hydrotreating achieves desulphurization with almost complete olefins saturation. Therefore causes substantial octane loss. Hence, may not be preferable with existing configurations of most of Indian Refineries that rely on FCC naphtha heavily to meet octane specification of MS Pool.

14. FCC Naphtha Hydrotreating • Selective Hydrotreating Selective Hydrotreating achieves desulphurization with very little olefins saturation, hence loss of octane is very minimal. This technology may be suitable for most of Indian Refineries.

15. FCC Naphtha Hydrotreating • Non-Selective Hydrotreating with Octane recovery Non-Selective Hydrotreating with Octane recovery achieves desulphurization with partial or total olefins saturation and employs other reactions e.g. Isomerization to gain lost octane during desulfurization. This technology may be the best suited for Indian refineries as some amount of LPG is also generated but proven ness of technology remains a issue.

16. FCC Naphtha Hydrotreating • Developing technologies Although new developing technologies are very promising yet the reliability and proven ness of the technology is an issue while selecting the technology for FCC Naphtha treatment.

17. FCC Naphtha Hydrotreating • Other Options Other options to meet gasoline Sulphur may also be built in while deciding the configuration of refinery. This may include routing heart-cut of FCC Naphtha splitter to Reformer. However, such strategies require thorough study as it may give rise to problems like benzene increase in reformate and also would require additional capacity in reformer.

18. Benzene Reduction In gasoline Pool • Main Benzene contributor in Gasoline pool is Reformer • If the reformer already exists, the choices to reduce benzene content in reformate are limited to options like lower operating severity, lower operating pressure and changes in catalyst formulation. However, these changes have limited effect on benzene content of reformate.

19. Benzene Reduction In gasoline Pool Benzene reduction options : • Avoid Benzene Production • Convert or destroy benzene • Recover Benzene for Petrochemical production

20. Benzene Reduction In gasoline Pool • Avoid Benzene Production: Pre-fractionation process scheme to reduce benzene content in reformate includes distillation of benzene precursors from the feed to reformer through a naphtha splitter. The precursors for benzene are Cyclohexane (CH), Methylcyclopentane (MCP) and the benzene contained in the Naphtha. The light naphtha containing the benzene precursors can be routed to a C5/C6 Isomerization Unit. This is the least expensive solution but has limitation of C7 content in ISOM feed. Also, since some benzene still will be formed in Reformer due to dealkalization of heavier aromatics and the dehydrocyclization of paraffins, this configuration will still not eliminate total benzene production in Reformer.

21. Benzene Reduction In gasoline Pool • Convert/ destroy Benzene : Another option is to postfractionate / extract the reformate and then hydrogenate the benzene into Cyclohexane which can then be routed to an ISOM unit to regain the octane loss in hydrotreating. The benzene rich stream from Reformate splitter can also be used as petrochemicals feed stock

22. Aromatics Reduction In gasoline Pool • It may be difficult to meet aromatics specifications along with octane specification if the MS Pool is only a mix of Reformate and light naphtha / isomerate. In such case, octane boosting additives may be required. • FCC Naphtha may dilute the aromatics in total pool but it has its own limitations due to high Sulphur and olefins content. • Another option can be to reduce severity of operation in reformer but this will decrease the octane of reformate and also the hydrogen production. • Changing feed cut points may also have little effect on Aromatics from Reformer

23. Aromatics Reduction In gasoline Pool • Other options for reduction in aromatics content of gasoline pool can be production of Petrochemicals after extraction / fractionation of reformate. • However, most of the refineries will have to manage the aromatics by dilution effect either through isomerate or through FCC Naphtha and / or ethrification / alkylation.

24. Olefins Management In gasoline Pool • FCC gasoline is the main contributor for the olefins in MS Pool. • FCC Naphtha hydrotreating can reduce olefins but with octane loss. • Etherification of C5 cut of FCC Naphtha can help in achieving olefins targets. However, oxygenates future is uncertain.

25. Octane Management In gasoline Pool Octane recovery may be achieved by : • Light Naphtha Isomerization • Etherification • Alkylation • Reforming

26. Octane Management In gasoline Pool • Light Naphtha Isomerization: Benefits of this process are that the Isomerate produced from ISOM Unit is a good diluent in terms of sulfur, aromatics and olefins and provides octane boost to the gasoline pool. However, requires large capital investment and have limitations of high RVP.

28. Octane Management In gasoline Pool • Etherification: Since, oxygenates future is uncertain, this process may not be considered as a good option. • Alkylation: Benefits of this process are that the Alkylate is a good diluent in terms of sulfur, aromatics and olefins and provides octane boost to the gasoline pool. However, HF acid usage in the process posses a safety issue.

29. Octane Management In gasoline Pool • Reforming: Reformate is the main constituent of today’s MS pool which contributes towards octane improvement. However, due to its high aromatic content, its use has to be limited in order to achieve total MS quality.

30. Octane properties of bases for gasoline pool.

31. Catalytic Reforming • Catalytic reforming is used to improve the quality of naphtha from the crude distillation unit.  The catalytic reforming unit uses a catalyst to allow the chemical reactions to take place under "reasonable" temperatures and pressure and "encourage" the desired hydrocarbons to be produced. • This process provides higher octane material to the gasoline pool to help meet the octane specifications on the gasoline.  The process also produces hydrogen which is used to remove sulfur from refinery streams in the hydrotreating processes. 

32. MS Stream Qualities

33. MS Stream Qualities (contd.)

35. GREEN FUELS & EMISSION CONTROL PROJECT, HPCL-MR LPG M S P O O L NAPHTHA HYDROTRTEATER & ISOMERISATION ISOMERATE SR FULL RANGE NAPHTHA NAPHTHA SPLITTER UNIT H2 FG NHT/CCR REFORMATE MAKE UP H2 TREATED LIGHT FCC GASOLINE TREATED HEAVY FCC GASOLINE PURGE GAS FCC NAPHTHA SELECTIVE HYDROGENATION & SPLITTER SECTION PRIME G+ UNIT MAKE UP H2 AXENS UNITS H2 MAKE UP FROM CCR UOP UNITS

36. Product Blending • Product blending is where the different petroleum fractions are combined together to make the final product.  The fractions are mixed so they meet the specifications discussed earlier.  Each product has a specific recipe that calls for the proper mix of petroleum fractions.  For example, in order to make gasoline, the refiner would mix naphtha, reformate, catalytic gasoline, Isomerate, etc., so that the mixture had the required octane number, vapor pressure, sulfur level, aromatics content, etc.  The process requires knowing these values for all of the components going into the blend. 

37. Conclusion • There is no single best solution • All the processes have advantages as well as drawbacks • Optimum solution for technological option for meeting gasoline pool specifications is refinery specific • For optimization of gasoline pool and selecting the best technology, a thorough study is called for taking into considerations specific to each refinery

38. Diesel Specifications

39. Major Changes in specifications • Sulphur Reduction • PAH Reduction • Cetane Improvement • Density Limitation • Reduction of 95% distillation point

40. Sulphur Reduction in Diesel Options for Sulphur reduction in diesel are: • Choose crudes or condensate low in Sulphur levels This option has limitation and can not be sustained due to high price of low Sulphur crudes and also limited possibility of meeting EURO III / IV diesel specifications

41. Sulphur Reduction in Diesel • Purchase low sulfur diesel blend stock This option can be used if such a blend stock is readily available but only small quantities of low sulphur diesel can be produced from this option

42. Sulphur Reduction in Diesel • Install / revamp existing DHDS Unit Option to install a new DHDS / DHDT unit or to revamp the existing DHDS Unit is refinery specific as the hydraulic capacity requirements as well as design limitations / plot area availability factors vary with each refinery. Revamps of most of the existing units may require installation of additional reactor(s), catalyst change and / or improving recycle gas purity.

43. Aromatics Reduction in Diesel Options for Aromatics reduction in diesel are: • Choose high paraffinic crudes Choosing this option will depend upon the availability and overall refinery configuration as well as the profitability of refinery while running such crude. This option may also pose limitations in other process units e.g. Reformer.

44. Aromatics Reduction in Diesel • Purchase low aromatics diesel blend stock This option can be used if such a blend stock is readily available but only small quantities of low aromatics diesel can be produced from this option. Also refiners may opt to route high aromatic diesel streams to alternate products e.g. Fuel oil but this will affect overall refinery profitability and reduce diesel volumes.

45. Aromatics Reduction in Diesel • Severe Hydrotreating Aromatics reduction can be achieved with change in catalyst from CoMo to NiMo but this may limit catalyst bed temperatures due to equilibrium shift at high temperatures or else the conventional catalyst systems can be used at high pressures and low LSHV. For significant reduction of aromatics noble metal catalyst systems may be required which require high capital investment. Thus option for aromatics saturation is also very specific for each refinery.

46. Cetane Number Improvement in Diesel Options for Cetane Number improvement in diesel are: • Use Cetane Improving additives This option will be mainly driven by the economics of this option in comparison to other options and will also depend upon availability of such additives.

47. Cetane Number Improvement in Diesel • Mild hydrocracking & Aromatics saturation This option may call for an additional stage and will depend upon the feed characteristics and therefore is also specific for each refinery.

48. Density Reduction in Diesel Density reduction is achieved during deep hydrodesulphurization and depends upon the feedstock properties as well as on the operating conditions. Around 10-20 Kg/M3 reduction can be expected as a result of sulphur removal and saturation of di- and tri- aromatic compounds. This combined with reduction in 95% distillation temperature will enable refiners to meet density specifications.

49. Reduction of 95% distillation point The best way of reducing 95% distillation point of the diesel is to adjust the draws of the crude distillation tower. This may result in reduction of diesel volume but will also help in density reduction, reduction in heavy aromatic compounds, refractive sulfur compounds that are difficult to treat will be removed from the feed and cold flow properties will also improve. Other option will be to go for mild hydrocracking.

50. Conclusion • There is no universal single solution • Optimum solution for technological option for meeting Diesel pool specifications is refinery specific • Detailed study will help for an integrated solution