CB426 Petroleum and Petrochemicals course

This presentation is related to petroleum and its derivatives. It was used as lecture material at Indian Institute of Technology Patna.

1. CB426: Petroleum Refinery & Petrochemicals LTPC 3-0-0-6

2. Reference Books W.L. Nelson, Petroleum Refinery Engineering, McGraw Hill, New York, 1961 K. H. Altgelt, M. M. Boduszynski, Composition and analysis of heavy petroleum fractions, Dekker, 1994 J. H. Gary and G. E. Handwork, Petroleum refining technology and economics, 4th Ed., Dekker, 2001

3. What is Petroleum? The petroleum, also called crude oil, is a fossil fuel. Like coal and natural gas, petroleum was formed from the remains of ancient marine organisms, such as plants, algae, and bacteria. Over millions of years of intense heat and pressure, these organic remains (fossils) transformed into carbon-rich compounds. It is thick flammable, brown to black mixture of solid, liquid and gaseous hydrocarbons that occurs naturally beneath the earth’s crust. We rely on as raw materials for fuel and a wide variety of products.

4. What is Petrochemicals? Petrochemicals are the chemical products obtained from petroleum by refining. Petrochemicals are used to manufacture thousands of different products that people use in daily life. Adhesives Cosmetics Fertilizers Paints Rubber Fabrics Plastics

5. Crude oil is black Gold! The world economy runs on the transactions of oil barrels done by the countries Its availability or shortage decides the situation of economy in a country Various other industries are related to petroleum industry

6. Classification of Crude oil Petroleum is a mixture of hydrocarbons and the non-hydrocarbon elements (small quantities of oxygen, sulphur, nitrogen, vanadium, nickel, and chromium) Hydrocarbon present in crude petroleum are classified into 4 general types: (a) Paraffins, (b) Naphthenes, (c) Aromatics, (d) Olefins Paraffins Naphthenes Olefins Aromatics Paraffin series of hydrocarbons is characterized by the rule that the carbon atoms are connected by a single bond and the other bonds are saturated with hydrogen atoms. General formula for paraffins is C n H 2n+2 Simplest paraffin: Methane (CH 4 ) followed by ethane; propane; normal and iso-butane; normal, iso and neo-pentane Naphthenes (Cycloparaffins): Hydrocarbons in which all of the available bonds of the carbon atoms are saturated with hydrogen are called Naphthenes. There are many types of Naphthenes present in crude oil. They are classified according to boiling range and their properties determined with help of correlation factors. Cyclopentane, Cyclohexane, Decahydronaphthene Olefins do not naturally occur in crude oils but formed during processing. Similar to Paraffins but at least two of the carbon atoms are joined by double bonds. General formula is C n H 2n Olefins are generally undesirable in finished products as the double bonds are reactive and the compound are more easily oxidised. Some olefins are desirable as have higher octane number than paraffin compounds with the same number of carbon atoms. Aromatic series of hydrocarbons is chemically and physically very different from the paraffins and Cycloparaffins (Naphthenes) Aromatic hydrocarbons contain a benzene ring which is unsaturated but very stable and behaves similar to saturated compound. Examples: Benzene, Toluene, Ethylbenzene, Ortho-Xylene, Meta-Xylene, Para-Xylene, Naphthalene) Diolefins are also present with 2 hydrogen atoms missing or 2 double bonds present in each molecule. Are extremely active due to double bonds present react with other unsaturated molecules forming HMW gum like solids

7. Crude assay analysis True boiling point distillation analysis °API gravity Correlation Index (CI) Watson characterization factor (K W ) Viscosity gravity constant (VGC) Pour point

8. True boiling point (TBP) analysis ( American Society of Testing and Materials, ASTM 2892 ) It is widely used batch distillation process for characterization of crude oils traditionally for marketing and refining purposes TBP distillation curve is obtained by plotting the cumulative mass or volume distillation fraction with increasing temperature and such a curve give a “footprint” of the composition of crude oils. The shape of these curves is dependent on the volatility of components in a given crude oil Gives information regarding the volatile behaviour of hydrocarbon mixtures It is a method to isolate the specified fraction from a crude oil for testing This method cannot be used for fractions with initial boiling points (IBP) greater than 400°C

9. True boiling point (TBP) analysis (ASTM 2892) Distillation is carried out at atmospheric pressure from IBP to about 210°C vapour temperature and at reduced pressure beyond this temperature Distillation under a partial vacuum avoids cracking of the more complex components Vapor temperatures measured at reduced pressure are translated to “Atmospheric Equivalent Temperature (AET)*” Samples of distillate are collected at specified temperature cut points Mass and density of each fraction are measured and distillation yield by mass is calculated TBP curves in cumulative mass fraction distilled vs. boiling temperature expressed in AET TBP curve describes a given crude oil in terms of its chemical make-up *Maxwell , J. B., and L. S. Bonnell . "Derivation and precision of a new vapor pressure correlation for petroleum hydrocarbons."  Industrial & Engineering Chemistry  49, no. 7 (1957): 1187-1196.

10. True boiling point (TBP) analysis (ASTM 2892) * Behrenbruch , Peter, and Thivanka Dedigama . "Classification and characterisation of crude oils based on distillation properties."  Journal of Petroleum Science and Engineering  57, no. 1-2 (2007): 166-180 . + https ://www.scribd.com/document/371674304/Tbp-Apparatus + Fig.1 TBP Set-up *Fig.2 TBP curve

11. True boiling point (TBP) analysis (ASTM 2892) Idealized method to achieve the best possible separation in distillation column Large number of theoretical plates for liquid-vapour contact An extremely high reflux ratio For number of theoretical plates more than 100 and a high reflux ratio of 100, the distillation curve will be as shown below: Heat P + R R P 50% % volume distillate 7 0% 100% T a T b Temperature (°C)

12. ASTM distillation ASTM distillation is also a batch distillation operation It operates without the presence of a contact plate and a reflux ratio of zero 50% % volume distillate 7 0% 100% T a T b Temperature (°C) Cooling water Heater % volume distilled RR=0 # Plates=0

13. Equilibrium Flash Vaporization distillation Heater Vapor Liquid Feed 50% % volume distillate 7 0% 100% T a T b Temperature (°C) TBP ASTM EFV Flash Drum

14. Important terms IBP: Initial boiling point Temperature at which 1 st drop of distillate appears FBP: Final boiling point Temperature at which highest boiling compound evaporates SL. No. Boiling point Abbreviation Formula 1. Cubic average boiling point CABP 2. Volume average boiling point VABP 3. Weight average boiling point WABP 4. Molar average boiling point MABP 5. Mean average boiling point MeABP SL. No. Boiling point Abbreviation Formula 1. Cubic average boiling point CABP 2. Volume average boiling point VABP 3. Weight average boiling point WABP 4. Molar average boiling point MABP 5. Mean average boiling point MeABP

15. Problem Compound Mol. Wt. (g/ moL ) Density @15°C (g/mL) Boiling point (°C) V (mL) Weight (g) Iso-pentane 72.2 0.62 28 0.1 0.062 3-Methylpentane 86.2 0.66 63 0.2 0.132 Iso-octane 114.2 0.69 99 0.3 0.207 Meta-Xylene 106.2 0.86 139 0.2 0.172 Hexyl cyclohexane 168.3 0.808 225 0.2 0.162 Gasoline consists of a mixture of iso -pentane, 3-Methylpentane, iso -octane, meta-xylene, and hexyl cyclohexane. Calculate MABP, WABP, VABP, CABP, MeABP. MABP=109.3°C, WABP=123.6°C, VABP=117.9°C, CABP=106.5°C, MeABP =107.9°C

16. Average boiling point: ASTM (D86) Distillation Curve  

17. Average boiling point: ASTM (D86) Distillation Curve Drawbacks of ASTM (D86) Distillation Curve Automation Long measurement time ~ 60 mins Precision Large sample volume required: 100 mL Reproducibility Fire extinguisher Fire Hazard Manual filling-Operation bias Limited sample range Errors in volume measurement Manual cleaning required Expensive consumables: Glass flask

18. Average boiling point: ASTM (D2887) Gas Chromatographic method c urve   https://www.agilent.com/cs/library/applications/application-distillation-astm-d2887-8890-gc-5994-0548en-agilent.pdf

19. Average boiling point: ASTM (D2887) Gas Chromatographic method c urve Benefits of ASTM (D2887) Gas Chromatographic Distillation Curve Fully automated High precision Repeatable Reliable Safer Small sample volumes Analysis setup Standard sample: Mix of C5 to C100 n-alkanes Crude oil sample No. of C-atoms B.P. Range (°C) Uses 1-4 0-30°C Natural Gas 5-10 30-180°C Gasoline 10-16 180-260°C Fuel for home, Jet fuel 16-60 260-350°C Diesel fuel >60 350-575°C Motor Oil >70 >490°C Fuel oil for ships >80 >580°C Roofing tar, Road tar

20. Average boiling point: ASTM (D2887) Gas Chromatographic method c urve Analysis setup Standard sample: Mix of C5 to C44 n-alkanes Crude oil sample No. of C-atoms B.P. Range (°C) RT (mins) C5 T5 R5 mins C6 T6 R6 mins C7 T7 R7 mins Up to C44 T44 R44 mins

21. Average boiling point: ASTM (D2887) Gas Chromatographic method c urve https://www.agilent.com/cs/library/applications/application-distillation-astm-d2887-8890-gc-5994-0548en-agilent.pdf Crude Oil sample Boiling point yield curve

22. °API Gravity °API gravity express the gravity or density of crude oil and liquid petroleum products. °API is devised jointly by API-American Petroleum Institute and the NIST-National Institute of Standards and Technology . API Gravity can be calculated as: °   Where °API=Degrees API Gravity SG=Specific Gravity at 60°F, 15.5°C Density is a temperature dependent property. °API gravity increases with increasing temperature as specific gravity decreases with increasing temperature.

23. °API Gravity https://www.engineeringtoolbox.com/api-gravity-d_1212.html °API

24. Correlation Index, CI Characterization of crude oil fractions : Useful in evaluation of individual fractions from crude oil   Where = Mean average boiling point (degree R ankine) = Specific gravity @ 15.6°C (or 60°F)   Crude oil composition CI Straight -chain Paraffins < 29.8 Naphthenic < 57 Aromatic > 75

25. Watson characterization factor, K W Classification of crude oil with respect to hydrocarbon types   Where = Volume or Mean average boiling point (degree R ankine) = Specific gravity @ 15.6°C (or 60°F)   Crude oil composition K w Straight -chain Paraffins 11-12.9 Naphthenic 10-11 Aromatic < 10

26. Viscosity gravity constant, VGC VGC is a useful function for the approximate characterization of the viscous fractions of petroleum   Where = Viscosity in Saybolt Universal Seconds (SUS) = Specific gravity @ 15.6°C (or 60°F)   Fractions VGC Straight -chain Paraffins 0.74-0.75 Naphthenic 0.89-0.94 Aromatic hydrocarbon 0.95- 1.13

27. Pour point It is the lowest temperature at which oil will pour or flow under gravity when it is cooled Petroleum products cannot be stored or transferred through a pipeline when temperature is less than its pour point Standard test procedures for measuring pour points of crude oil or petroleum fractions are described in the ASTM D97 and ASTM D5985 method Pour point of crude oils relates to their paraffin content; the higher the paraffin content, the higher the pour point. Pour point of crude oil varies from -60°C to 30°C

28. Refining processes Distillation & Solvent extraction: Physical separation process Cracking, v isbreaking , coking: Breakdown processes Reforming, alkylation, isomerisation, and polymerization: Rebuilding processes Reforming Alkylation Isomerization Polymerization Is a process to convert low-octane naphthas into high-octane gasoline blending components Is a process in which light gaseous hydrocarbons are combined to produce high-octane components of gasoline Is similar to reforming, the hydrocarbon molecules are rearranged converting normal paraffins to iso-paraffins . Is the process of converting light olefin gases into hydrocarbons of higher molecular weight and high octane number that can be used as gasoline blending stocks Cracking Visbreaking Coking Is a process in which large complex hydrocarbons broken down into smaller lighter components for commercial use Is a mild thermal operation with/without blending with lighter heating oils to reduce viscosity of bottom residue to fuel oil Is a process of upgrading bottoms from fractionating column into higher-value products i.e. petroleum coke

29. Simple Refinery Flow Separation Finishing Dewaxing Conversion 1 1. LPG: Propane + Butane 2 . Light straight run Naphtha: Pentane + Slightly heavier Naphtha range material 2 3 . Kerosene + gas oil 3 Lubricating oil + Wax 4 4. Vacuum distillation residue 5 5 . Heavy gas oil 6 6 . VDR 7 7. Light or heavy gas oil 8 8 . By-product from CC unit 9 9 9. Heavy Naphthas 10 10. VDR

30. Cracking process Heavier fractions are converted into lighter fractions by application of heat with/without catalyst Thermal cracking Catalytic cracking Carried out without catalyst Carried out with catalyst Accomplished by heating feed: 450° to 750°C at 1-70 atms Accomplished by heating feed: 480 to 550°C at 0.7 to 1.4 atms Catalysts: Synthetic composites of alumina/silica Acid treated natural clays Zeolites Ease of cracking depends upon the boiling range and chemical nature of feed Accelerates the reactions Modify yield and nature of product Important reactions: Decomposition; Dehydrogenation; Isomerization; Polymerisation Production of gasoline from gas oil Gasoline obtained is superior in quality

31. Cracking process CH 3 (CH 2 ) 8 CH 3 -------  CH 3 (CH 2 ) 4 CH 3 + CH 3 -CH 2 -CH=CH 2 n- Decane n- Hexane 1-Butene 2CH 3 -CH 2 -CH=CH 2 ↔ CH 3 -CH 2 -C-C=CH 3 CH 3 CH 3 CH 3 1-Butene iso-Octene

32. Visbreaking process Visbreaking is a thermal cracking process carried at 470° to 520°C and 4-20 atms Residues from vacuum distillation units with/without blended with gas oils subjected to thermal treatment to produce heavy furnace oil (fuel oil) Meet the requirement of viscosity and pour point Visbreaking depends upon the temperature and time Thermal severity index (TSI) is a measure of “Thermal severity” under reaction conditions - TSI= Thermal severity index (TSI) is a measure of “Thermal severity” under reaction conditions

33. Coking process Residues from refinery is the feed for coking It is the severe thermal (480-590°C) cracking of vacuum residue Due to high severity of thermal cracking during coking, the residue feed is completely converted to gas, light ( naphthas ) and medium (gas oils) distillates, and petroleum coke C oke used as a fuel or as a filler for manufacturing anodes for the electrolysis of alumina 

34. Reforming process Naphtha splitter Light Naphtha to Gasoline pool Heavy Naphtha Catalytic Reformer H 2 High Octane Gasoline Distillation Crude oil Naphtha Reforming is a process of preparing high-octane gasoline Can be performed with/without a catalyst Upgrading by rearrangement or reforming of molecules without affecting the molecular weight Catalysts used: Chromia-alumina; Platinum on a silica-alumina/alumina base

35. Reforming process H 2 C CH 2 H 2 C CH 2 CH 2 CH CH 3 CH 3 + 3H 2 Methyl cyclohexane Toluene H 2 C CH 3 H 2 C CH 2 CH 2 CH 2 CH 3 CH 3 + 4 H 2 Toluene n -heptane

36. Crude oil desalting process Process water Wash water pump Crude oil Crude charge water Mixing valve Static mixer Electrostatic De-salter (electrically powdered) Atmospheric distillation Desalted crude Deoiler hydrocyclone Effluent water to VOC stripper Emulsion breaking chemicals

37. Atmospheric and Vacuum Distillation Units Steam Steam Steam Pump arounds (several) Desalter 120-150°C Furnace exit 400°C max Stripping steam t ray 32 Wash tray 1 To Light End Unit (LEU) 43°C Water Naphtha Cooling water Kerosene Light gas oil Heavy gas oil 380°C Vacuum distillation unit Atmospheric residue Lubricating oil To deasphalting and coking Vacuum distillate residue (VDR) 1 atm 0.004 atm 0.04 atm Fuel oil Furnace Gas LPG Stabilized Naphtha Atmospheric distillation unit

38. Topping refinery Important units in the topping refinery operation Equipment Function Furnace Preheating of crude oil Heat exchangers Exchange heat between fractions and crude oil Condensers To condense the out let stream and send back Fractionating towers: ADU and VDU Separation of spectrum of products based on relative volatility Steam-stripping columns Secondary column for further rectification Pumps and connecting pipes Connecting equipment/units Storage and accumulation tanks For storage

39. Operational data for ADU and VDU Parameters ADU Tower diameter (in meters) 2.5-12 No. of trays 25-40 ∆P max / tray 0.015 atm ∆P b/w flash zone to tower top 0.5 atm ∆P b/w furnace outlet to flash zone 0.4 atm Pressure at tower top 1.5 atm Tower top temperature 100-110°C Reflux drum pressure 1.5 atm Steam per barrel of crude processed 5 kg Parameters VDU Tower diameter (in meters) Up to 14 Pressure at tower top 0.02 atm Tower top temperature 225-250°C Steam per barrel of crude processed 0.3 to 5 kg

40. Light Gas Recovery Pre-treatment Desalting H 2 O+Salts Crude Oil Atmospheric distillation CH 4 , C 2 H 6 C 3 -C 4 Saturates Isomerization n-C 4 Alkylation i -C 4 Un-saturates Polymerization Propylene Butylene Ammonia Manufacturer Light Polymer: C 6 -C 9 Propylene tetramer: C 12 Butane LPG Fuel or Synthesis gas Fuel or Synthesis gas H 2 SO 4 NaOH NH 3 Sulphur removal Catalytic Reforming Petrol (Low grade) Benzene Detergent Manufacturer Sulfonated/ Sulfated detergents H 2 N 2 Gasoline (High Octane) Gasoline pool i-Octane H 2 S to H 2 SO 4 Naphtha splitter Heavy Naphtha Kerosene Naphtha Catalytic cracking Gas Oil Kerosene Diesel Fuels Diesel/Jet Fuel Domestic heating oil V vacuum distillation Visbreaking Fuel oil D easphalting Phenol solvent extraction Deasphalted oil T reated oil MEK solvent Dewaxing Treating Blending Additives Lube oil Wax Acid Treating Lubricating Oils Paraffin Wax Asphalt Coking Petroleum coke

41. Refinery processes Refinery processes Physical processes Chemical processes Distillation Absorption Extraction Adsorption Crystallization Cracking Reforming Polymerization Alkylation Isomerization Hydrodealkylation Hydrogenation Unit Operations Unit Processes

42. Chemistry of Cracking P rocesses C racking involves the thermochemical conversion of hydrocarbons by heating at high temperatures of 400-700°C in the absence of oxygen Purpose is to crack larger hydrocarbons to smaller hydrocarbon molecules Both non-catalytic and catalytic cracking is applicable in petroleum refinery Use of catalyst in cracking reduces the severity of operating conditions and increases the selectivity of product formation with less side reactions Fixed bed catalytic cracking was applied in 1936 Moving and fluidized bed catalytic cracking was applied in 1945

43. Chemistry of Cracking P rocesses Thermal cracking mechansims Free radicals are formed by the cleavage of C-C or C-H bonds with each fragment retaining one of the pair of shared electrons that make up the bond These free radicals are highly reactive species C 4 H 10 ----- C 4 H 9 . + H . Initiation C 4 H 9 . -----  C 3 H 6 + CH 3 . Propagation CH 3 . + RH -----  CH 4 + R . Propagation R . -----  Olefin + R 1 . Propagation 2R 1 . -----  Olefin + Alkane Termination C 1 and C 2 gaseous hydrocarbons are major products from thermal cracking Free radical chain reaction Thermal polymerization: Polymerization of olefins forms larger HCs than present in the feedstock Thermal coking: Free carbon is formed on complete degradation of HCs. RH ----- → x C + y H

44. Catalytic Cracking Mechanisms Catalytic cracking produces no C1 and C2 gaseous HCs Secondary and Tertiary HCs isomers are formed Relatively less coke (free carbon) is formed. In case feedstock containing aromatics: Aromatic rings are stable but long alkyl chain attached to the rings are subjected to cracking Iso -Octane CH 3 -C-CH 2 -CH-CH 3 CH 3 CH 3 CH 3

45. Cracking process conditions Process parameters to be optimized: (i) Optimum time, (ii) Temperature, (iii) Pressure, (iv) Catalyst-to-feed ratio and these process specifications depend on feed, reactivity, desired product, and coking tendency Feed Process Time (seconds) Temperature (°C) Pressure (atm) Thermal cracking CH 4 HC ≡CH production 0.1 1350 1 C 2 H 6 H 2 C=CH 2 production 1 800 12 Gas oil Thermal cracking 60 600 21 Residual crude Coking ---- 500 2-3 Catalytic cracking Gas oil High yield of petrol fraction Space velocity: 0.5-3/hr Catalyst-oil wt. ratio: 5-20 ---- 480 1.7-2

46. Houdry catalytic cracking reactor Houdry introduced continuous catalytic cracking process in 1936 Reactor type: Fixed bed reactor packed with natural alumina-silica catalyst pellets 10 min make-clean cycle Expensive tubular reactor and shell side molten salt circulated Expensive alloy for reactor construction to withstand oxidation/reduction Furnace 800°C Gas oil Strip w/steam ~ 5mins Combustion gases Gas Gasoline Light gas oil Heavy gas oil Hot air Alumina-silica catalyst

47. Moving/fluidized bed catalytic cracking reactor In moving /fluidized bed, the catalyst is moved from cracking to regenerating section control Catalyst selection: Composition, form, regenerative properties, poisoning, aging etc. Catalyst composition Acid-treated silica-alumina Synthetic oxide: 13-15% Al 2 O 3 87-85% SiO 2 b) Natural clays of bentonite and kaolin c) synthetic alumina/silica + zeolites (introduced in 1965) 3-4 mm pellets for moving bed 20-80 mesh micro-spherical synthetic catalyst for fluidized bed Fine powder with an average particle size of 60–75 μm ( particle size distribution ranging from 20 to 120 μm ) Catalyst is poisoned by metals: Fe, Ni, V, Cu Catalyst should have high tolerance to Sulphur Once through reactor the yield is up to 50%; recycle leads to yield above 50% is standard to give highest petrol yield

48. Moving/fluidized bed catalytic cracking reactor Balance b/w cracking and coking rates to decide optimum temperature Increasing pressure reduces unsaturation and octane number, increases coke production but increases reactor throughput Note: Light olefin gases such as ethylene, propylene, butylene are polymerized to HMWs HCs increasing the ON that can be used as gasoline blending stocks. 5-20 wt. ratio used with 0.3-0.6% coke levels in reactor Balancing of mechanical loss of catalyst is essential and additions dropping to 10-25% of initial value Deliberate additional discard is practiced where cracking capacity is tight 1.4 -2 atm best range ~500°C best average

49. Advantage of catalytic over thermal cracking Produces high quality (80-90 ON) petrol from any crude Selective cracking and less light ends More Isomerization Greater portion of aromatics Less polymerization Relatively little coke Greater ability to tolerate high “ Sulphur ” feedstocks Uniformity of temperature and pressure control

50. Fluidized bed CC unit Distillation column Steam Feed Air Lift Cracked Product Slurry Regenerated catalyst Spent catalyst Regenerator Flue gas to stack Cyclones Recycle Gas oil Reflux drum Gas Petrol

51. Moving bed CC unit (700-750°C) (150°C) 500°C https://www.e-education.psu.edu/fsc432/content/fluid-catalytic-cracking-fcc

52. Thermal coking Coking processes are implemented to refine heavy end of crudes Coking is the most severe thermal process to treat VDR On thermal cracking during coking, VDR is completely converted to gas, light and medium distillates, and coke 3 different coking processes are used in refinery: (i) Delayed coking, (ii) Fluid coking, and (iii) Flexi-coking Common objective of coking is to maximize the distillate product yield by rejecting large quantities of carbon residue known as petroleum coke Petroleum coke find applications as fuel or as filler manufacturing anodes Petroleum coke is characterized by its sulphur and metal contents Out of 3 coking process, delayed coking is the preferred approach Typical yields from a complete coking operation Light ends 5 wt. % Petrol 20 wt. % Gas oil 60-65 wt. % Coke 10-15 wt. %

53. Process conditions for coking Higher temperatures result in higher yields of gas, petrol, and coke Gases obtained from thermal coking are more olefinic Petrol (~20 wt. %) is not stable hence hydrogenation treatment required to improve its stability Higher pressures are not desirable yielding more gaseous products and coke Optimum temperature and pressure condition for coking: ~500°C and 2-4.5 atms

54. Delayed coking process Steam is added to prevent coking in the heater Necessary heat for coking is provided in the heater whereas coking takes place in coke drum hence the process is called “delayed coking” Hot vapours from the top of the coke drums are quenched by incoming VDR feed in fractionator to prevent coking in fractionator The heat from the hot vapours provide the sensible heat to feed to strip the light fractions of VDR 2-4.5atms 500°C https://www.e-education.psu.edu/fsc432/content/delayed-coking Hot vapours & steam

55. Fluidized coking process https://www.e-education.psu.edu/fsc432/content/fluid-and-flexi-coking Coker Unit

56. Flexi-coking process https://www.e-education.psu.edu/fsc432/content/fluid-and-flexi-coking Fuel gas of Synthesis gas: H 2 , CO, CO 2 , CH 4 Coker Unit

57. Catalytic Reforming Catalytic reforming is used to convert HCs to aromatics Aromatics like Toluene have high ON of 104 Aromatics used as a raw material for petrochemical industries Catalytic reforming feedstock are HCs fractions : Naphtha grades Naphtha is a generic name given to light HCs boiling in the gasoline range (60-200°C) Light Naphthas < 100°C Intermediate Naphthas Heavy Naphthas > 150°C

58. Common reactions in Catalytic reforming of Naphthas Dehydrogenation (Endothermic reactions) CH 3   CH 3   3H 2 Cyclization CH 3 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 3   n-heptane Dimethyl cyclopentane CH 3 CH 3   CH 3 M ethyl cyclohexane M ethyl cyclohexane Toluene - H 2

59. Common reactions in Catalytic reforming of Naphthas Isomerization   CH 3 Hydrocracking (not desirable) CH 3 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 3   n-heptane Propane C 3 H 8 Methyl cyclohexane + H 2 E thyl cyclopentane   -3H 2 + C 4 H 10 Butane ON is less than aromatics

60. Catalytic Reforming Catalysts Catalytic reforming, dehydrogenation catalyst are required Catalysts coupled to “ Alumina ” or “ Silica-alumina ” base matrix: Platinum Molybdenum oxide Chromium oxide Cobalt molybdate “ Pt ” though expensive is best option in terms of selectivity and lack of hydrocracking In catalytic reforming, whatever carbon depositing takes place on catalyst surface can be removed by steam or air oxidation Reforming is done under high H 2 pressure so that many catalyst poisons ( S and N ) are hydrogenated and easily removed from the catalyst surface High H 2 pressure suppress coking of catalyst to larger extent Heavy metals such as “ Pb ” and “ As ” permanently damage “ Pt ” catalyst

61. Catalytic Reforming Catalysts Thermodynamically, it is predicted that dehydrogenation is feasible at low pressures and high temperature High temperature also favours hydrocracking and carbon deposition Carbon deposition can be suppressed by high hydrogen pressures with use of product hydrogen recycle A comprise is made b/w catalyst activity and yield of reformate of a given ON with process conditions Catalyst Platinum Pressure 15-30 atm Temperature 470-525°C Space velocity 1.5 kg/hr of feed per kg catalyst

62. Catalytic reforming: Dehydrogenation Catalytic reformates make excellent blending stocks since they contain no olefins R eformates are also oxidation resistant (stable) Reformates have high octane no. ( ≥ 80) R eformate are low in sulphur and gum Broader boiling range making good cold weather petrol Produced reformates form basis for the aromatic petrochemical industry 10 2 30 4 50 20 4 60 8 100 Pressure (atm) % mole yield aromatics (Toluene) 500°C 3 00°C M ethyl cyclohexane (Reactant) Toluene (Product)

63. Catalytic reforming: Dehydrogenation Crude oil Distillation column Heavy ends H 2 Recycle gas Light ends Reformate #1 *Reactor #2 Reactor #3 Reactor Hydrogenation Purifier Naphtha stock/ Gasoline low grade stock (To remove S and N) Primary Heater Excess H 2 gas #2 Heater #3 Heater Furnace *Fixed bed reactor “Pt” catalyst size 1.5-3 mm

64. Catalytic Alkylation Alkylation is addition of any alkyl functional group to a compound Alkylation processes are similar to those of polymerization but olefins reacts specifically with iso-paraffins Alkylate produced is a higher quality product for petrol blending: High ON ~ 85-95 Stable & saturated branched paraffins Alkylation units are more expensive to build and operate but the demand of these units is high due to high ON products A refinery has economic justification for both alkylation and polymerization units, selective olefin feed preparation is used to maximize capacity 2-butene which polymerizes least rapidly, is separated from catalytic cracking distillate for alkylation feedstock Iso-paraffins are produced in isomerization units

65. Catalytic Alkylation Reactions Olefins Iso-paraffin Alkylates + C 3 -C 4 : Propene and B utene HMWs iso-paraffins (a) Carbonium ion formation C-C=C-C + H 2 SO 4 C-C-C-C + HSO 4 + - Butene (Olefin) Acid catalyst Carbonium ion Initiation C-C-C-C + C-C-C + C H Carbonium ion C-C-C-C + C-C C C Iso-butane ( Iso-paraffin) n-Butane ( n-paraffin) Reactive iso-paraffin carbonium ion + Propagation C-C C C + + C-C=C-C Butene (Olefin) iso-paraffin carbonium ion C-C-C-C-C C C + C Carbonium ion intermediate Addition

66. Catalytic Alkylation Reactions C-C C C + + C-C=C-C Olefin iso-paraffin carbonium ion C-C-C-C-C C C + C Carbonium ion intermediate Addition C-C-C-C-C C C + C + C-C-C C H Iso-paraffin Carbonium ion intermediate C-C-C-C-C C C C + C-C C C + iso-paraffin carbonium ion Regeneration 2,2,3 Tri-methyl pentane

67. Catalytic Alkylation Reactions Olefins Iso-paraffin Alkylates + C 3 -C 4 : Propene and iso-butene HMWs iso-paraffins (a) Carbonium ion formation C=C-C + H 2 SO 4 C-C-C + HSO 4 + - Propene (Olefin) Acid catalyst Carbonium ion Initiation C-C-C + C-C + C C Carbonium ion C-C-C + C-C C C Iso -butane ( Iso -paraffin) Propane ( n-paraffin) Reactive iso -butyl ( iso -paraffin) carbonium ion + Propagation C C C C C-C + + C=C-C Propene ( Olefin) iso-paraffin carbonium ion C-C-C-C + C Carbonium ion intermediate Addition

68. Catalytic Alkylation Reactions C-C-C-C C C + C + Carbonium ion intermediate C-C-C-C C C C + C-C C C + iso-paraffin carbonium ion (Regeneration of c arbonium ion) Regeneration 2,2,3 Tri-methyl butane (Alkylate) + C=C-C Propene ( Olefin) iso-paraffin carbonium ion C-C-C-C + C Carbonium ion intermediate Addition C C C-C C C Iso-butane ( Iso-paraffin) C C C-C +

69. Catalytic Alkylation: Catalysts Sulfuric acid (H 2 SO 4 ) Hydrofluoric (HF) 85% acidity, circulated @ 4-10°C in emulsion from containing 50% acid Competitive with H 2 SO 4 but consumes only 1/10 th the weight of H 2 SO 4 used Acid consumption : 0.05-0.2 ton acid per ton feed requiring H 2 SO 4 plant near refinery and spent acid disposal for economical operation HF requires extreme safety in handling Produces lower grade alkylate Operates @ 37°C level, requiring no refrigeration HF distilled and recycled as compared to H 2 SO 4 spent acid disposal

70. Catalytic Alkylation: Reaction conditions Parameter Conditions Temperature Sulfuric acid (H 2 SO 4 ) Best yield : Low T H 2 SO 4 catalyst more T sensitive 0°C lower limit because of viscosity effect 21°C upper limit because of sulfation reaction Hydrofluoric (HF) No effect of T on HF in the T range of -20°C to 60°C Standard temperature: 37°C Pressure Feed Reaction time Just above bubble point pressure of mixture of HCs No real effect of increasing pressure Iso-butane/olefin ratio: to avoid polymerization, a large excess of iso-butane is used ranging from 5:1 to 15:1 Contact time : 5-50 min depending upon the type of liquid-liquid contact Reactions are exothermic

71. Catalytic Alkylation : H 2 SO 4 process H 2 SO 4 process Removal of mercaptans Removal of residual acid 4-10°C Recycle of Iso-butane

72. Catalytic Alkylation : HF process Caustic wash Drier Settler HF Stripper Deisobutanizer Depropanizer Olefin feed + C 4 Feed Fresh caustic Spent caustic H 2 O Acid oils Impeller reactor HF Rerun Column C 3 HF Make n-Butane + Alkylate i-C 4 Defluorinator (Caustic wash or adsorption by bauxite adsorbent) HF HF Process Removal of mercaptans Recycle of Iso-butane Recycle of Iso-butane (to supress polymerization)

73. Isomerization Catalytic isomerization of n-paraffins (less ON) to isomers for alkylation feedstock is a necessary refinery operation Reaction : Reaction is mildly exothermic Catalysts: AlCl 3 -HCl promoted adsorbed on porous carriers or used as a liquid Both vapour & liquid phase catalytic isomerization reactions are in commercial practice Catalyst: 0.3-1.5 tons of isomer per kg of catalyst Reaction conditions : T, P, space velocity, feed purification Temperature: Balance b/w equilibrium which is favoured @ low T and rates 100-150°C used with 40-50% conversion and recycle to achieve 98% yield Pressure: No effect on reaction, 17-27 atm, used as an economic balance b/w throughput and reactor vessel costs Space velocity: 0.5-2.5 m 3 /hr feed per m 3 of catalyst Feed purification : Must remove water, S & mercaptans compounds which can react with AlCl 3 50 100 150 50 100 Mol % of iso-paraffin i-C 5 i-C 4

74. Isomerization Drier Reactor *AlCl 3 Recovery Flash drum AlCl 3 make up Vapour fraction: Light Ends to HCl absorber HCl Stripper HCl HCl make-up Caustic Wash Fractionator Fresh caustic Spent Caustic n -Paraffin Recycle n -Paraffin feed Isomerized product * AlCl 3 is volatile at reaction condition and soluble in liquid HCs (Removal of HCl traces)

75. Hydrodealkylation Combined hydrogenation and de-alkylation process is employed Petroleum refinery is a source of aromatics Development of catalytic reforming processes Development of improved separation processes for isolating high purity aromatics Reforming produces about equal yields of benzene, toluene, and xylene; market for benzene is high Dominant benzene is obtained from hydrogenation and de-alkylation process Hydrodealkylation of Toluene Hydrodealkylation of Xylene o,m,p-C 6 H 4 (CH 3 ) 2 + H 2 → C 6 H 5 CH 3 + CH 4 C 6 H 5 CH 3 + H 2 → C 6 H 6 + CH 4 C 6 H 5 C 2 H 5 + H 2 → C 6 H 6 + C 2 H 6 Hydrodealkylation of Ethylbenzene C 6 H 5 CH 3 + H 2 → C 6 H 6 + CH 4 2C 6 H 6 + H 2 → C 12 H 10 + H 2

76. Hydrodealkylation Rani, J., Thakur, P. and Majumder , S., 2023. Energy integration of hydrodealkylation (HDA) of toluene. Materials Today: Proceedings. Reaction conditions: Temperature: 500-600°C Pressure: 20-60 bar Addition of CH 4 is a strategic decision that enhances safety, temperature control, reactivity control, and economic efficiency Catalyst offers lower temperatures and higher selectivity Catalyst: Platinum supported on silica-alumina, chromium oxide 600°C/20-60 bars C 6 H 5 CH 3 + H 2 → C 6 H 6 + CH 4 Unreacted Toluene + Biphenyl side reaction product

77. Polymerization Olefinic feed polymerizes to form dimer and trimer of C 3 and C 4 olefins from catalytic cracking converted to a liquid blending component for gasoline pool with improved ON Reactions are highly exothermic i.e. 11-16 kcal of heat per gmol of olefinic feed Catalyst: Acid catalysts are required. Solid catalysts are favoured. 65% H 2 SO 4 at 20-36°C (cold process) or at 93°C (hot process) Liquid H 3 PO 4 acid, phosphoric acid on inert carrier such as silica or Kieselgurh Cu 2 P 2 O 7 (Copper pyrophosphate) catalyst supported on charcoal Reaction conditions: T, P, t and reaction rate Temperature : (a) Sufficiently high for acceptable rate but too high T i.e. 400-500°C gives tar deposition (b) 150-220°C acceptable range for solid catalysts Pressure: (a) High P increases conversion at lower T and reduces HMWs polymer formation; (b) 25-100 atm. better range Reaction time : (a) Balance for satisfactory conversion to petrol without excessive high HMW polymer formation (b) Space velocity of 0.7-3 kg/hr feed per kg of catalyst (c) Reaction rates vary with type of crude oil

78. Polymerization: Reaction Carbonium ion formation: C=C-C-C C-C + C C Carbonium ion H + (acid catalyst) C-C + C C (b) Addition reaction: C-C + C C Olefin + C-C-C-C-C C C C + Carbonium ion Olefin Intermediate Carbonium ion

79. Polymerization: Reaction (c) Regeneration: 2,2,4 Tri-methyl pentene (d) Isomerization reaction: C-C-C-C + Carbonium ion C-C-C-C-C C C C + C-C-C=C-C C C C + H + ↔ Carbonium ion C-C + C C Intermediate Carbonium ion

80. Polymerization: Block diagram C 3 -C 4 Olefin Feed Spent Caustic Fresh Caustic Water wash Cooling water Tubular reactor (5-15cm dia tubes) Depropanizer Debutanizer Butanes to isomerization Propane H 2 Stabilizer H 2 Polymer Gasoline Waste water (Removal of mercaptans ) (Remove traces of alkali) Highly exothermic reaction; requires proper control of temperature to avoid HMWs formation Polymer gasoline is stable after mild hydrogenation Propane Mixer Mixer

81. Treatment of petroleum products/fractions Physical impurities Chemical impurities Sand/mud/moisture/catalyst dust/solvent droplets Gas treatment: Washed with water & dried Liquid-settling or by using dehydrating agent Sulphur/Nitrogen/ Oxygen Major impurity H 2 S, Mercaptans,CS 2

82. Removal of sulphur compounds Removal of S: Sweeting processes Mercaptans (Methyl mercaptan: CH 3 SH) are oxidised to disulphide Physical extraction process-H 2 S is extracted using ethanolamine In situ destruction of S compounds-treatment of M ercaptans with 93% H 2 SO 4 Catalytic desulphurization-Hydrogenation and hydrolysis of CS 2 in presence of a catalyst Methyl mercaptan ( CH 3 SH): S containing volatile organic pollutant (SVOC ) highly toxic strong volatility belongs to malodorous gas posing a threat to human life and health Oxidation of these mercaptans to disulfides by contacting the rich caustic stream with a solid catalyst in the presence of oxygen followed by separation of the disulfides from the treated caustic. Doctor solution: Sodium plumbite (a solution of lead oxide in caustic soda) H 2 S disgusting rotten egg odour H 2 S in high concentration can rapidly paralyze human’s nerve, which means it is hard to notice the danger because H 2 S will immediately kill people H 2 S adsorption by liquid reagents (basic aqueous solution or ethanolamine) is a widely accepted strategy to collect H 2 S gas in industry

83. Removal of sulphur compounds Destruction of S compounds by H 2 SO 4 acid Reacted with concentrated H 2 SO 4 Acid sludge is disposed Catalytic desulphurization In catalytic desulphurization reactions: Molecule bearing S is not removed (as seen in extraction or acid treatment) but only S atoms are picked up. M aterial loss is negligible with possible recovery of S. Cu-Cr-Al catalyst Cu- Cr- Va catalyst Co- Mo oxide catalyst (widely used catalyst) RSH + H 2 SO 4 ----  RSHSO 4 + H 2 O RSH + RSHSO 4 ---  (RS) 2 SO 2 + H 2 O (RS) 2 SO 2 --------  R 2 S 2 + SO 2

84. Lead doctoring process Removal of S: Sweeting processes Mercaptans (Methyl mercaptan: CH 3 SH) are oxidised to disulphide Lead doctoring process Reaction: Na 2 PbO 2 + 2RSH ->(RS) 2 Pb + 2NaOH ( RS) 2 Pb +S -> R 2 S 2 + PbS Catalyst regeneration PbS + 2NaOH + ½ O 2 -> Na 2 PbO 2 + S + H 2 O

85. Merox process Removal of S: Sweeting processes Mercaptans (Methyl mercaptan: CH 3 SH) are oxidised to disulphide Merox process: Catalyst contains cobalt phthalocyanine deslofenamide, tetrasolfonamide, tetrasulfonate dissolved in fresh NaOH Extraction Reaction: General equation: NaOH + RSH ---->NaSR + H 2 O Redox step NaSR +H 2 O + 1/2 O 2 ----> 2NaOH + R 2 S 2 2RSH + 1/2 O 2 -------  H 2 O + R 2 S 2 Merox-catalyst

86. Lead doctoring process: Sodium plumbite Reactor-1: Na 2 PbO 2 + 2RSH ->(RS) 2 Pb + 2NaOH Sweet product Reactor-2: (RS) 2 Pb +S -> R 2 S 2 + PbS 5-15 mins S Drain Fresh caustic- Sodium plumbite sol n Sour gasoline Regenerator Air Air Discharge solution T=100°C P= 1-5 Atms Settler-1 Settler-2 Ratio of doctor sol n : Gasoline is 1:5 Time of contact : 0.5-1 min (Black suspension) PbS + 2NaOH + ½ O 2 -> Na 2 PbO 2 + S + H 2 O Recycle Na 2 PbO 2 Discharge sol n

87. Merox process Extractor Merox Separator Air Towers (2) Towers (1) Sweet product Air Air Recycled Merox Disulphides Separator Pump Sour Gasoline Merox NaOH + RSH ---->NaSR + H 2 O NaSR +H 2 O + 1/2 O 2 ----> 2NaOH + R 2 S 2 Treated Gasoline stream + H 2 O + NaOH + Co salt + NaSR *Co-salt Compressor *Proprietary Liquid catalyst: Co-salt complex Merox http://www.hitekengineers.com/liquid-liquid-extraction-column.html

88. Catalytic desulfurization Separator Sweet Product Furnace Heater Catalytic reactors Sour gasoline Cooler 400°C 400°C H 2 S Vaporized Gasoline Cu-Cr-Al catalyst Cu- Cr- Va catalyst Co- Mo oxide catalyst H 2 gas

89. Treatment of lube oil fraction Treatment is done to improve the quality of lube oil (lubricating oil) Fluidity of oil Oil viscosity Colour and stability Viscosity index (VI) is an important characteristic of lube oil. Desirable is “viscosity remain constant across a wide temperature range” Lubricant with higher VI is more desirable as it provides more stable lubricating film over a wider temperature range Treatment methods for lube oil Clay treatment Solvent treatment Dewaxing

90. Treatment of lube oil fraction V iscosity index is calculated from: W here is viscosity at 40°C of an oil with VI = 0 is viscosity at 40°C with a VI = 100 is viscosity of the tested oil at 40°C. The values of L and H for a specific viscosity of oil is available in ASTM D2270*   *ASTM International, “Standard Practice for Calculating viscosity index from Kinematic Viscosity at 40 °C and 100 °C,” ASTM International, Conshohocken, PA, 2016.

91. Solvent extraction method Solvent treatment focuses on improvement of certain characteristics of lube oil Lube oil is used to maintain fluidity, viscosity at operational conditions Solvent treatment is carried out to improve VI by removal of: (a) Heavy Aromatics and heavy naphthenes, (b) Asphalt, and (c) Wax Solvent extraction method: (a) Phenol solvent, (b) Furfural solvent, (c) N-methyl pyrrolidone (NMP) These solvents remove aromatic compounds responsible for increase in the viscosity C 5 H 9 NO

92. Solvent extraction method Phenol solvent extraction Furfural solvent extraction T range: 60-100°C Solvent: Feed ratio: 1.5-2.5 Lube fraction: Paraffinic/Naphthenic Raffinate yield: 50-90% depending upon the amt. of solvent used. Higher solvent amt. provides better quality of Raffinate but less yield Phenol treated lubes posses good oxidation stability with less sludge formation and carbon deposition T range: 75-125°C Solvent: Feed ratio: 1-2 Used for: Lube oil, Gasoline, Diesel Widely used solvent Raffinate does not possess much solvent Has tendency to react with O 2 forming HMWs and losing its solvent properties, hence require N 2 inert atmosphere

93. Problem 2 Compound Con. (g/L) BP (°C) V (L) Iso-pentane 72.2 28 0.1 3-methylpentane 86.2 63 0.2 Iso-octane 114.2 99 0.3 Meta-xylene 106.2 139 0.2 Hexylcyclohexane 168.3 225 0.2 Calculate: Weight average boiling point (WABP) and plot: Percentage yield (%) vs. BP (°C) for the given data set form ADU

94. Viscosity Index of Hydrocarbons Viscosity index of Hydrocarbons Type of Hydrocarbon Viscosity index n-Paraffins i-Paraffins Mono-cyclic naphthenes Bi-cyclic naphthenes Aromatics 175 155 142 70 50

95. Lube oil extraction process: Furfural Oil feed Inert gas Raffinate (Lube oil) to Dewax Process Raffinate Stripper Inert gas to Recycle Furfural accumulator Furfural stream Furnace Furnace Inert gas Extract stripper Furfural Extract Extraction Tower Furfural rich extract Lube oil rich raffinate Furfural rich fraction 60-90°C 10-14 atms

96. Lube oil extraction process: Furfural Inert N 2 gas is used as a stripping medium as furfural solvent is prone to polymerization on exposure to steam and air Furfural extraction process is designed to produce lube oil having desirable lube oil qualities High viscosity index (VI): Removal of heavy aromatics and naphthenes Stability Colour Critical operating variables for furfural extraction unit: Furfural-to-oil ratio: It has greatest effect on the quality and yield of the raffinate Extraction temperature: T is selected as a function of lube oil viscosity and miscibility Extract recycle ratio: Extent of separation b/w the lube oil and aromatics

97. Lube oil extraction process: NMP Oil feed Steam Stripper Steam Raffinate (Lube oil) to Dewax Process Raffinate Stripper NMP accumulator NMP stream Furnace Furnace Steam Stripper Steam Extract stripper NMP flash Extract Extraction Tower NMP rich extract Lube oil rich raffinate NMP rich flash

98. Lube oil extraction process: NMP This process was developed as a replacement for phenol extraction because of the safety, health, and environmental problems associated with the use of phenol NMP possess 69 % lower viscosity than phenol at 50°C C omplete miscibility of NMP with water, no azeotrope formation of NMP with water Recovery of NMP is better than that for phenol, and NMP losses are only 25 to 50% those of phenol The lower viscosity of NMP gives greater throughput for a given size tower For a given solvent-to-oil ratio for NMP and phenol extraction, the quality of product obtained is same but raffinate oil yields average 3 to 5% higher for the NMP extraction.

99. Dewaxing of Lube oil Lube oil heavy fraction contains high amt. of wax which causes viscosity to increase High wax content affects viscosity and flow property of oil Pour point is also affected due to wax presence Lube oil stocks must be dewaxed or will not flow properly at ambient temperature Dewaxing is done in order to regulate oil flow property and pour point Dewaxing is one of the most important and most difficult processes in lubricating oil manufacturing Dewaxing by the application of refrigeration to crystallize the wax and solvent to dilute the oil portion sufficiently to permit rapid filtration to separate the wax from the oil

100. Dewaxing of Lube oil: Solvent dewaxing 2 principal solvents used in solvent dewaxing processes: Propane Ketones Solvent act as a diluent for the high molecular-weight oil fractions to reduce the oil viscosity and provide sufficient liquid volume to permit pumping & filtering Difference in both methods lies in the equipment used for refrigeration and solvent recovery portion of the process About 85% of dewaxing units based on ketone solvent

101. D ewaxing method Readily available, less expensive, and easier to recover Large differences b/w filtration temperatures and pour point of finished oils (5-25°C) Direct chilling can be accomplished High filtration rates can be obtained because of its low viscosity at very low temperatures Small difference b/w filtration temperature & pour point of dewaxed oil (5-10°C) Lower pour point capability Lower refrigeration requirements Fast chilling rate; Shock chilling can be used to improve process operation Good filtration rates but lower than for propane Propane dewaxing method Ketone dewaxing method

102. Ketone dewaxing method MEK Accumulator Inert Rotary filters Cooler Lube oil feed Chiller unit Wax Filterate Steam Steam Wax to storage Inert Gas Wax strippers Stripped Solvent Vapours Oil stripper Inert Gas Dewaxed Oil to storage MEK makeup Wax Rundown

103. Composition of lube oil Lube oil is composed of 80-90% of petroleum hydrocarbon distillates: Property Paraffinic oil Naphthenic oil Chemical structure Long carbon chains Multiple carbon rings Resistance to oxidation High Medium Pour point High Low Viscosity High Low Volatility Low High Specific gravity Low High

104. Propane deasphalting process Deasphalting is removal of the asphaltene portion of the feedstock for catalytic conversion units Catalyst performance is greatly impaired by heavy metals and carbon presence of feedstock for CCU Asphaltene HMW aromatic compounds contains most metals which make up most of the asphalt portion of the residue Asphaltenes are composed mainly of polyaromatic carbon ring units with o Oxygen Nitrogen S ulfur heteroatoms, combined with trace amounts of heavy metals: vanadium and nickel and aliphatic side chains of various lengths Molecular structure of Asphaltene

105. Propane deasphalting process Asphaltene portion in the lube oil results in the following High pour points L arge viscosity changes with temperature (low VI) Poor oxygen stability, poor colour , high cloud points high carbon- and sludge forming tendencies. S olubility of Lube oil HC in propane decreases with an increase in temperature In 40-60°C T range, propane has solvent properties: Lube oil HC are propane soluble Propane at critical T of 96.8°C: Lube oil HC are insoluble In 40-96.8°C T range: HMW asphaltenes are insoluble in propane Separation by distillation is generally by molecular weight of the components and solvent extraction is by type of molecule Propane deasphalting falls in between these categories because separation is a function of both molecular weight and type of molecular structure

106. Propane deasphalting process Oil feed Extraction Tower Asphalt heater HP oil vaporizer Propane accumulator CW H 2 O Propane LP Oil stripper 157°C 15 atm 154°C 0.3 atm Cooler De-asphalted Oil HP Asphalt flash tower 274°C 15 atm LP Asphalt stripper Asphalt Steam Propane compressor 60°C 33 atm 4 0°C Steam Steam Propane vapours Propane vapours Propane vapours Asphalt rich phase

107. Natural Gas Sweeting For commercial applications such as CNG, Power generation etc. Natural gas should meet specific requirements for quality Should not contain higher levels of CO 2 , NO x , and H 2 S To regulate emissions and release of toxic gases, authorities mandate natural gas producers to minimize S content in their products. Sour gas must be sweetened before it is sent out from the refinery or gas processing plant Natural gas is termed as ‘sweet gas’, if it contains only trace quantities of H 2 S and CO 2 Sweet gas is pure natural gas and is non-corrosive, requires little refining, and we can transport and market it safely

108. Natural Gas Sweeting Reasons for gas sweetening process : Removal of the contaminants from gas is required for the reason of: Corrosion control Toxicity Gas/Liquid product specifications To prevent poisoning of catalyst in downstream facilities Control of the overall heating value of the natural gas To meet environmental requirements: CO 2 , H 2 S are very common contaminants in Natural gas Reason for CO 2 removal for gas sweetening When combined with water forms carbonic acid (H 2 CO 3 ) which is corrosive CO 2 reduces the BTU value of the gas If present in 2-3% gas is not saleable Reason for H 2 S removal for gas sweetening Extremely toxic gas Highly corrosive Reason for Mercaptans (R-SH): Removal for gas sweetening It has smell If comes in contact with bacteria (inside the final product storage) then released H 2 S 2R-SH Bacteria → R-SSR + H 2 S

109. Natural Gas Sweeting Gas well Temp Pressure Raw Gas Condensate (Oil) & water removal Condensate to an Oil refinery Waste H 2 O Acid gas Removal Acid gases (H 2 S, CO 2 ) Sulphur Unit Claus Process Metal S Unreacted H 2 S/ SO x / CS 2 etc. Tail gas Treating Off gas to initiator Dehydration (Removal of H 2 O in Glycol unit) Mercury Removal ( Adsorption on activated Carbon /other sorbents ) Molecular Sieves Activated carbon N 2 Rejection N 2 Rich Gas Cryogenic Process Adsorption Process Absorption Process NGL Recovery Turbo-expander & D emethanizer Absorption To sales gas pipeline

110. Types of gas sweetening techniques Chemical reaction process for gas sweetening: Amine process MEA (Mono ethanol amine: HOCH₂ CH ₂NH ₂ ) DEA (Diethanol amine: HN(CH₂CH₂OH)₂ ) DGA (Diglycolamine: C 4 H 11 NO 2 ) DIPA (Di- iso Propanol Amine: C 6 H 15 NO 2 ) MDEA (Methyl Dethanol Amine: CH 3 N(C 2 H 4 OH) 2 )

111. Natural Gas Composition and Specifications Natural gas as recovered at the wellhead consists of mostly methane (CH 4 ) , ethane (C 2 H 6 ) , propane (C 3 H 8 ) , butane (C 4 H 10 ) , and pentane (C 5 H 12 ) Impurities found in natural gas Water : Most gas produced contains water, which must be removed. Concentrations range from trace amounts to saturation S species : If the H 2 S concentration is greater than 2 to 3%, carbonyl sulphide (COS), carbon disulphide (CS 2 ), elemental S and M ercaptans may be present Mercury : Trace quantities of mercury may be present in some gases; level reported vary from 0.01 to 180 μ g/m 3 . Typically, the mercury level in pipeline gas should be reduced to 0.01 μ g/m 3 Diluents : The gases CO 2 , H 2 S, NO x Oxygen : A significant amt. of corrosion in gas processing is related to O 2 contamination

112. Specifications for Pipeline Q uality G as https://www.e-education.psu.edu/fsc432/content/natural-gas-composition-and-specifications

113. Amine Process      

114. Claus Process Claus process is the most significant elemental ‘S’ recovery process from gaseous H 2 S Gases with >25% H 2 S content is suitable for recovery of ‘S’ from the Claus process H 2 S produced in desulphurization of recovery products is converted to ‘S’ in Claus plant Thermal stage Catalytic stage H 2 S is oxidised @ temperatures above 850°C and precipitates to elemental ‘S’ ∆H=-187 KJ/mol Air: Acid gas ratio is controlled in such a way that all of the H 2 S is converted to SO 2 Main portion of the hot gas in the combustion is cooled down leading to condensation of elemental ‘S’ formed.   H 2 S is oxidised @ temperatures above 850°C and precipitates to elemental ‘S’ A small portion of the process gas (containing 20-30% of sulphur content in the feed stream) goes to the catalytic stage. In presence of activated alumina or titanium dioxide the following reaction takes place: ∆H=-41.8 KJ/mol  

115. Claus Process ∆H =-187 KJ/mol   (H 2 S + CO) Elemental ‘S’ Elemental ‘S’ (S+ H 2 S + SO 2 ) ∆H=-518 KJ/mol   H 2 S + SO 2 ∆H=-41.8 KJ/mol   TiO 2 Al 2 O 3 TiO 2 Al 2 O 3 TiO 2 Al 2 O 3 Heating is necessary to prevent ‘S’ condensation in the catalyst bed Catalytic conversion is maximized @lower T but should be above the dew point of ‘S’ i.e. 115°C

116. Claus Process If acid gas feed to the combustion chamber contains COS and CS 2 , they are hydrolyzed in the catalytic reactor: Tail gas from Claus process still containing combustible components and Sulphur compounds (H 2 S, H 2 , and CO) burned in incineration unit  

117. Dehydration process Glycol dehydration is a liquid desiccant system for the removal of water from natural gas and natural gas liquid Most common and economical means of H 2 O removal from natural gas stream Glycols typically seen in industry include: Triethylene glycol ( TEG ) : HOCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 OH Diethylene glycol (DEG): (HOCH 2 CH 2 ) 2 O Ethylene glycol (MEG): CH 2 OHCH 2 OH Tetraethylene glycol (TREG): HOCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 O CH 2 CH 2 OH Issues with presence of H 2 O in natural gas : @ low ‘T’ H 2 O can freeze in piping @ high ‘T’ forms hydrate with CO 2 and CH 4 plugging equipment & piping Free water phase containing portions of acid gas and can cause corrosion Pipeline quality specification for gas that the H 2 O content < 100 mg/mL

118. Dehydration process https://en.wikipedia.org/wiki/Glycol_dehydration HC vapours HC liquids The reboiler temperature is limited to 204°C to prevent thermal degradation of glycol Elevated pressure for absorption

119. Mercury removal from Natural gas Wang, Jiaxin , Ying Liu, Tao Wang, Mohamed A. Serageldin , and Wei-Ping Pan. "A review on mercury in natural gas and its condensate: Accurate characterization and efficient control technologies for total and speciated mercury." Fuel 355 (2024): 129526. ‘ Hg ’ presence in Natural gas: conc n <10 ppb to >1 ppm ‘ Hg ’ removal is critical It is toxic Poisons catalysts used in downstream processing units Can damage downstream equipment through liquid-metal embrittlement Corrosion leading to crack initiation and propagation in equipment constructed of aluminium Damage to equipment results in numerous equipment failures, unscheduled shutdowns ‘Hg’ in natural gas and its condensate mainly originate from source rocks that undergo thermal conversion to become hydrocarbons Presence of Hg compounds Monomethyl mercury HgS, Hg 2 Cl 2 Dialkyl mercury Elemental Hg

120. Mercury removal process http:// www.pall.com Provide consistent gas quality for Hg content typically < 10ng/m 3 Purpose of having liquid/gas coalesce is to remove liquid H 2 O & HC that shorten adsorbent life Purpose of having gas particle filters is to remove protect metering, downstream processes and other instrumentation from abrasive adsorbent fines

121. Feedstock of Petrochemical These are the chemicals that are made from petroleum and natural gas About 5% of the oil and gas consumed each year is needed to make all the petrochemical products Petrochemicals play an important role on our food, clothing, shelter and leisure Typical feedstocks to petrochemical processes include: C1 compound : Methane & Synthesis gas C2 compound : Ethylene & Acetylene C3 compound : Propylene C4 compound : Butanes and Butenes Aromatic compound : Benzene

122. C1 compound: Methane & Synthesis gas Methane Synthesis gas ( H 2 and CO) Steam (catalyst) / O 2 Carbon black Hydrogen NH 3 N 2 from Air Pyrolysis Partial combustion H 2 and CO 2 Steam Acetylene Dimer Chloroprene HCl Vinyl Chloride/acetate HCl/Acetic acid Chloroethylenes Chlorine alkali Hydrogen cyanide Acrylonitrile Air O 2 CO 2 Urea Ammonia nitrate Nitric acid Air Methanol Formaldehyde Air (Catalyst) Methyl chloride Methylene dichloride Chloroform Carbon tetrachloride HCl Chloromethanes Chlorine Catalyst

123. Methanol Industry Cost of methanol production for a unit producing 5,000 metric tonnes per day methanol based on 2012 coal prices in China and USA and 2012 natural gas prices in China, Middle East, and USA.  Feedstock Coal China Coal USA Natural gas China Natural gas USA Natural gas Middle East Feedstock cost 50 $/ MT* 70 $/MT 12 $/ mmBTU + 4 $/mmBTU 1 $/mmBTU Total capital investment, $ Million 1,240 1,500 930 1,160 1,260 Operating cost, $/MT           Raw material 61.41 99.78 469 160 43 Utilities 73.97 51.53 9 5 5 Fixed cost 38.09 41.93 26 30 33 Cash cost of production 173.47 193.24 504 195 79 Depreciation 60.61 74.4 43 58 63 Return on capital 74.36 89.76 56 70 76 Total cost of production 308.44 357.4 603 323 219 W.H. Calkins, Chemicals from methanol. Catal . Rev. Sci. Eng. 26(3 and 4), 347–358 (1984) *MT : Metric ton; + mmBTU : Metric million British Thermal Unit

124. Methanol formation from Synthesis gas Synthesis gas High P and moderate T conditions Methanol Side reactions:       ∆H ≈ - ve   C 2 H 5 OH; CH 3 CH 2 CH 2 OH (CH 3 ) 2 O Mixed catalyst : Oxides of Zn, Cr, Mn, Al Properties and uses CH 3 OH is a colourless liquid that boils @ 65°C It solidifies @ -94°C It forms explosive mixture with air and burn with a non-luminous flame It is completely miscible in water It is used as rocket fuel, solvents, and antifreeze

125. Methanol formation from Synthesis gas Flash drum Settler KMnO 4 Ether Tower CH 3 OH Tower Water Heavy Alcohols Methanol Crude Methanol Fuel gas Let down to 14 atms Reactor: 200-350 atms 300-375°C Steam Purge gas Ether CO + H 2 (1:2.25) Synthesis gas Recycle: H 2 & CO Vapours Thick walled reactor needs to be designed Undesired alcohols formation reduces the yield of product KMnO 4 removes the HCs such ketones & aldehydes formed as side products

126. Formaldehyde production Reactions: Oxidation: Pyrolysis:   Undesired Reactions:   Silver or Zinc oxide catalyst on wire gauge Atmospheric pressure & 500-600°C Uses of HCHO Formaldehyde is stable in only water and there, 37% HCHO sol n with 3-15% methanol (stabilizer) is produced as formalin Formalin is used as a preservative Resins used in the manufacture of composite wood products Building material and insulation Zn-Ag oxide catalysts (Nanoparticles) SEM image Movahedi , F., Masrouri , H. and Kassaee , M.Z., 2014. Immobilized silver on surface-modified ZnO nanoparticles: As an efficient catalyst for synthesis of propargylamines in water.  Journal of Molecular Catalysis A: Chemical ,  395 , pp.52-57.

127. Formaldehyde production CH 3 OH evaporator Methanol Catalytic Reactor Light Ends Stripper Scrubber Heated Air Air Vent gases (H 2 , CO 2 ) Water Alcohol Stripper Aqueous HCHO 37% sol n Recycle CH 3 OH vapor Pyrolysis reaction:   Oxidation reaction:  

128. Water C2 Petrochemicals Ethylene Polyethylene Catalyst Vinyl acetate Oxygen/acetic acid catalyst Ethylene oxide Ethylene chlorohydrin Oxygen /Catalyst Hypochlorous acid Ethylene dichloride Chlorine Ethanol amines Ammonia Ethylene glycol Water Polyglycols Di and Triethylene glycols Glycol ether & polyglycol (ether) HCN Acrylonitrile Alkali Dehydrogenation Vinyl chloride HCL Ethylene dibromide Bromine Ethyl chloride HCl Ethyl alcohol Water (catalyst) Acetaldehyde Sulfuric esters H 2 SO 4 Ethyl benzene Styrene Refinery cracked gas Cracking of ethane, propane Alcohols/alkyl phenol Benzene Acetic Acid

129. Ethylene dichloride production Reactions:   Undesired product: Uses of ethylene dichloride It is used in production of vinyl chloride Used as an intermediate in the production of tetrachloroethylene Used as an solvent in textile , metal cleaning and adhesive industries HCl & C 2 H 6 is also formed Reaction occurs in a liquid phase reactor with ethylene dichloride serving as the liquid medium Catalyst: FeCl 3 or ethylene dibromide ; T=50°C and P=1.5-2 atm Reaction is exothermic Crude product is washed with NaOH so as to remove HCl

130. Ethylene dichloride production Catalyst: FeCl 3 /C 2 H 2 Br 2 Chlorine Ethylene HCl scrubber 6-8% NaOH sol n Off gases H 2 /CH 4 /C 2 H 4 /C 2 H 6 Wash Refrig Water Caustic Wash 6-8% NaOH sol n Reactor Heat control loop Settler Fractionator Crude C 2 H 4 Cl 2 Wash Ethylene Dichloride Heavy Ends Heterogeneous reaction Reaction medium:   40-60°C 1.5-2 atm Gaslift reactors https://en.wikipedia.org/wiki/Iron(III)_chloride Vapours:   Liquid:   Liquid:   Removal of HCl

131. Vinyl chloride production Reaction in gaseous form:   Uses of Vinyl chloride It is a monomer in formation of PVC which is used in making of pipes, wire coatings, packaging material Industrially used as an extraction solvent for sensitive products It is used as aerosol propellant It is used in making of C hloroacetaldehyde Catalyst: Charcoal is used as the catalyst The reaction is a reversible gas phase reaction The product is stabilized using a stabilizer as vinyl chloride is highly reactive without stabilizer Quenching is done in order to inhibit the reverse reaction Source: Google images

132. Vinyl chloride production C 2 H 4 Cl 2 storage 4 atms/ 500°C Tubular Pyrolysis Furnace EDC Quencher Vinyl chloride Fractionator EDC Fractionator Vinyl chloride Stabilizer Polyvinyl chloride Vapor C 2 H 4 Cl 2 Cold Liquid EDC Quench HCl Flue gas Dryer C 2 H 4 Cl 2 Vapor recylce Removal of moisture Steam Vapor C 2 H 4 Cl 2 Liquid C 2 H 4 Cl 2

133. Ethylene Oxide production Reaction:   Uses of Ethylene Oxide It is used in manufacturing of following petrochemicals: Ethanol amines Mono ethylene glycol (MEG) Diethylene glycol (DEG) Non ionic surfactants Glycol ethers It is used as a permanent antifreeze for automobile radiators In making of non-ionic detergents Ethylene to air ratio : 3-10% (Air is used in excess) Side reaction products : CO 2 and H 2 O Catalyst: Silver oxide on alumina Operating T and P: T=250-300°C and 8-20 atm Supressing agent for side reaction: EDC  

134. Ethylene Oxide production H 2 O Steam H 2 O absorber Desorber Recycle H 2 O Recycle Purge Stream Stripper Stripper Light ends + H 2 O Heavy ends (Side reactions: Glycols due to presence of H 2 O) Ethylene oxide Ethylene Air Fixed bed tubular reactor: 250-300°C CO 2 /N 2 / Steam/Air Ethylene oxide Air/CO 2 /N 2 / Steam Ethylene oxide in H 2 O H 2 O Ethylene oxide + Light ends +Heavy ends + H 2 O Dowtherm Volume ratio of Ethylene to air ratio is critical Undesired hydration reaction leads to glyco l Fluidized bed reactors instead of packed bed reactors helps to avoid hot spots 8-20 atm + DOWTHERM ™ is a synthetic organic thermal fluid mixture of two highly stable compounds (biphenyl (C12H10) and diphenyl oxide (C12H10O)

135. Ethylene Glycol production Reactions:   Ethylene Glycol (Ethane 1,2 diol)     Diethylene glycol Triethylene glycol Monoethylene glycol Operating conditions: T=200°C and P=15 atms Volume ratio of Ethylene oxide to water: 10:1 maximizes MEG production H igher glycols is inevitable as ethylene oxide reacts faster with ethylene glycols than with water Reaction can be catalysed either by acids or bases or can occur at netural pH under elevated temperature with excess water Ethylene oxide

136. Ethylene Glycol production Uses of Ethylene Oxide MEG is used in making polyesters (polymer) find applications in clothing, food packaging, and plastic bottles Polyester DEG is making coolants, pesticides, rubber compounding, plasticizer, polyurethane, alkyl resins Ethylene glycols also used in pharmaceuticals and cosmetics

137. Ethylene Glycol production Water Ethylene oxide Water recycle Evaporator Series Drying Still Reactor Fractionator Reactor (200°C and 15 atms) Fractionator Fractionator Heavy ends MEG D EG TEG

138. Acetic acid production Reaction:   Ethanol Acetaldehyde Acetic acid Uses of Acetic acid It is used in pharmaceutical industry Used as a plasticizer Used as a solvent Used in production of Vinyl acetate, esters Used as a preservative Used as a food additive Used as a flavouring agent K 2 Cr 2 O 7 (Potassium dichromate) is a strong oxidising agent Primary alcohols are oxidized to carboxylic acids in two stages - first to an aldehyde and then to the acid.   O H “Oxygen atom from oxidising agent” O H     OH O

139. Vinyl acetate production Reaction: Uses of Vinyl acetate Adhesives Paints and coating industries Textiles Plastics Paper and board industries Polyvinyl acetate emulsions & resins Reaction occurs in presence of ‘ Pd ’ and ‘ CuCl 2 ’ catalyst Operating condition: T= 423-463 K ; P=6-10 atms By-product formation: H 2 O , gases mainly containing CO 2 OH O   O ∆H ≈ - ve

140. Vinyl acetate production Acetic Acid Container (Evaporator) Reactor Product Container Oxygen + Ethylene Injector Heat Exchanger https://www.researchgate.net/figure/A-schematic-of-the-vinyl-acetate-production_fig1_241111755 T = 423-463 K ; P=6-10 atms Packed bed of ‘ Pd ’ and ‘ CuCl 2 ’ catalyst Vinyl acetate CO 2 Waste water

141. Styrene from Ethyl benzene Reactions:   Uses of Styrene Step1: Alkylation of benzene Catalyst used: AlCl 3 granules Operating T and P: T=95°C and 1 atm   Step1: Alkylation of Benzene Step2: Dehydrogenation of ethylbenzene Styrene is mainly used for making : P lastics toys H ousing for machines R efrigerator door and air conditioner cases Latex, synthetic rubber, and polystyrene resins P lastic packaging, disposable cups and containers, insulation and other products   Step2: Dehydrogenation of ethylbenzene Catalyst used: SnO or FeO Operating T : T=800°C

142. Styrene from Ethyl benzene Catalytic Dehydro unit Quench Tower Unsaturated Steam (3-5% wetness) Ethyl benzene Benzene column H 2 O Vent Ethyl Benzene column Superheated steam (To maintain T) C 6 H 6 C 6 H 5 -CH 3 to recovery 90°C Finishing column Styrene Tar 800°C/FeO catalyst Side reactions:   Vac. Component B.P (°C) Benzene 80 Toluene 111 Ethyl benzene 136 Styrene 145 Vac. Vac. Cooling coils Ethyl benzene, Styrene, heavy end

143. Styrene from Ethyl benzene Major engineering problems: Unsaturated steam is used for quenching instead of water to avoid additional unwanted reactions. Styrene, benzene, toluene, and ethylbenzene are closely boiling systems hence vacuum distillation Ethyl benzene is prone to fire hazard hence its handling is hard Styrene oxide is a derivative of styrene which is carcinogenic hence its formation must be prevented

144. C3 Petrochemicals Propylene is used in many of the world’s largest and fastest growing synthesis materials and thermoplastics https://www.blueweaveconsulting.com/report/global-propylene-market/report-sample Global Propylene Market to Boost In Coming Years – Projected To Reach 132.1 Metric Tons In 2028, at a CAGR of 6.1 %

145. C3 Petrochemicals Refinery Grade Chemical Grade Propylene CH 3 CH=CH 2 Cumene Iso-propyl alcohol Oxo alcohol Propylene oxide Acrylonitrile Propylene is a by-product of steam crackers Recovery of propylene from FCC light ends Propane dehydrogenation

146. C3 Petrochemicals Product profile of C3 petrochemical: Propylene Miscellaneous chemicals 1-butanol 2 ethyl hexanol Allyl chloride Epichlorohydrin Polymer Polypropylene Polyacrylamide Nylon 66 Acrylic sheets Propylene oxide Polyether polyols Glycol ethers Isopropyl amines Propylene carbonate 1-butanol 2 ethyl hexanol Allyl chloride Epichlorohydrin Polypropylene Polyacrylamide Nylon 66 Polyether polyols Glycol ethers Isopropyl amines Propylene carbonate

147. C3 Petrochemicals Product profile of C3 petrochemical: Propylene Propylene glycol Polyester resins Food additives Cellophane Paints and coatings Plasticizers Functional fluids Antifreeze Acrylonitrile Acrylic fiber Acrylic acid Acrylates Methyl methacrylates Adiponitrile Isopropanol Acetone Cosmetics Solvents Pharmaceuticals, isopropyl acetate Polyols Polyurethane and Polyester Methyl methacrylates Adiponitrile Acetone isopropyl acetate Polyurethane

148. Polypropylene: C3 Petrochemicals Polypropylene is a low density, semi-crystalline, thermoplastic polymer Polypropylene processes are based on low pressure processes using Ziegler-Natta catalyst Its properties are similar to polyethylene but it is slightly harder and more heat resistant It is a white, mechanically rugged material and has a high chemical resistance Polymerization Resin degassing Pelletizing Product Propylene Catalyst Google images

149. Polypropylene: C3 Petrochemicals Fluidized Bed Reactor 1 Unreacted Gas separator Fluidized bed Reactor 2 Catalyst Unreacted Gas separator Propylene to resin loading Ziegler-Natta catalyst Ziegler-Natta catalyst Operating condition : T =35°C and P=32 atms Catalyst: TiCl 4 on MgCl 2 in slurry from in mineral oil Propylene monomer Polypropylene Degassing Unit

150. Acrylonitrile: C3 Petrochemicals Reactions:   Uses of Acrylonitrile Reaction conditions: Catalyst used: * Mo-Bi oxide Operating T and P: T = 400-500°C and 1.5-3 atm pressure Stoichiometric ratio: C 3 H 6 : NH 3 : O 2 =1:1:1.5   A crylic fibers Nitrile rubber Adiponitrile and acrylamide ABS (acrylonitrile butadiene styrene) and SAN (Styrene acrylonitrile) plastic By-products: Acetonitrile Hydrogen cyanide * Bereś , J., Janik , A. and Wasilewski , J., 1969. Preparation of bismuth-molybdenum catalysts. Journal of Catalysis, 15(2), pp.101-105. (  

151. Acrylonitrile: C3 Petrochemicals Reaction kinetics: 3 reactants and a solid catalyst is used. Selectivity is critical to avoid side reactions Multiple cyclone separators required to avoid loss of Mo-Bi catalyst Propylene contamination with 30% propane is inevitable hence propane must be fractionated Cynahydrins (RHOHCN) forms during reaction which further dissociate to form volatile contaminants. Hence, oxalic acid is used to decrease dissociation reaction. Component BP Acrylonitrile 78°C Acetonitrile 82°C acrylonitrile-water azeotrope 69.5°C acetonitrile-water azeotrope 75.5°C Patent no.: US2415662A

152. Cumene: C3 Petrochemicals Reactions:   Uses of Cumene Reaction conditions: Catalyst used: Solid Phosphoric acid on alumina Operating T and P: T=350°C and 25 atm pressure Stoichiometric ratio: C 6 H 6 : C 3 H 6 = 2:1 M anufacture other chemicals such as Phenol , Acetone , A cetophenone , and Methyl styrene It is used as a thinner in paints and enamels It is a component of high octane motor fuels By-product: Di-isopropyl benzene        

153. Cumene: C3 Petrochemicals https://richardturton.faculty.wvu.edu/files/d/0a396264-d517-4a27-9510-eeea01c214ed/cumene-a.pdf Vaporizer T=350°C P=25 atm T=40°C P=25 atm Separator Distillation Tower

154. Isopropanol: C3 Petrochemicals Reactions: Step1: Sulfation Step2: Hydrolysis   Isopropyl acid sulphate (Gas) (Liquid)   Side reaction: Di-isopropyl ether formation   Reaction conditions: Operating T and P: Room temperature and 20-25 atm pressure

155. Isopropanol: C3 Petrochemicals US6906229B1: Process for hydrolyzing di-isopropyl ether to isopropyl alcohol by catalytic distillation using a solid acid catalyst

156. Petrochemicals from Aromatics Main aromatics as raw materials for Chemical synthesis are: Benzene (B) Toluene (T) Xylene (X) Naphthalene (N) Primary sources for BTXN raw materials are: Oil Coal BTXN Chemicals CH 3 CH 3 CH 3 CH 3 CH 3 CH 3 CH 3

157. Petrochemicals from Aromatics Pertinent properties: Molecular weight: 148.1 g/ moL M.P.: 130.6°C B.P: 284.5°C Density @ 4°C: 1.53 g/cm 3 Ignition temperature: 588°C Solubility: Slightly soluble in hot water and ether, sublimes below the melting point Grades: Technical (99-99.8%), Pure (>99.8%) as flakes or pellets Phthalic anhydride Uses of phthalic anhydride Used in making resins and plasticizer Google images Quantitative requirements Basis: 1 ton of Phthalic anhydride (75% yield) Naphthalene 1.15 ton Air 22.6 ton Ortho-Xylene 0.96 ton Air 20.1 ton C₆H₄(CO)₂O

158. Petrochemicals from Aromatics Reactions: a) Produced by the oxidation of “ Naphthalene ” and “ Ortho-Xylene ” Phthalic anhydride +   +   + 2   + 3   V 2 O 5 400°C V 2 O 5 480°C- 600°C + 3   Vanadium pentoxide catalyst Google image ∆H = -ve

159. Petrochemicals from Aromatics Major side reactions: Complete combustion ( 15-20% yield) Minor side reactions produces 3-5% yield Maleic anhydride as by-product Phthalic anhydride +     +   +   +         + +

160. Petrochemicals from Aromatics Process flow diagram H 2 O Precipitator Fluidized bed reactor Naphthalene or Ortho-Xylene Vent gases to H 2 O scrubber Fluidized bed Condenser Tar Steam Phthalic Anhydride Pellets or re-melted and flaked Air

161. Petrochemicals from Aromatics Reactions: (a) Peroxidation: Cumene + Air Cumene Hydro Peroxide (b) Hydrolysis: Cumene Hydro peroxide + H 2 SO 4 Phenol + Acetone Phenol For Peroxidation: Aqueous emulsion is prepared using emulsification agents Operating conditions: Normal T & P Emulsification agent: NaOH (Alkali) For hydrolysis: 10-25% H 2 SO 4 (Aqueous) is used Operating conditions: 55-65°C and atmospheric pressure conditions Side by-products: Acetone Acetophenone Methyl styrene

162. Petrochemicals from Aromatics Cumene Air Oxidizer Cleavage H 2 SO 4 H 2 O Fractionator Acetone Fractionator Fractionator Fractionator Crystallizer Phenol Acetophenone H 2 Methyl Styrene + Cumene Recycle Cumene Vac. Vac. Vac. Alkali Crude Phenol Wash Tower

163. Petrochemicals from Butene and Butadiene Adiponitrile (ADN): N ≡C-(CH 2 ) 4 -C≡N Molar mass: 108.14 g/mol Boiling point: 295°C Density: 970 kg/m 3 Viscous colourless dinitrile and is an important precursor to the polymer Nylon 66 1,3-Butadiene is hydrocyanated to Adiponitrile (ADN) in 2 steps: CH 2 =CH-CH=CH 2 CH 2 =CH-CH 2 -CH 2 -C ≡N 1,3-Butadiene 4-Pentenenitrile CH 2 =CH-CH 2 -CH 2 -C ≡ N N ≡C-(CH 2 ) 4 -C≡ N 4-Pentenenitrile Adiponitrile 1,3-Butadiene: CH 2 =CH-CH=CH 2 HCN HCN

164. Petrochemicals from Butene and Butadiene 1,3-Butadiene is hydrocyanated to Adiponitrile (ADN) in 2 steps: CH 2 =CH-CH=CH 2 CH 2 =CH-CH 2 -CH 2 -C ≡N 1,3-Butadiene 4-Pentenenitrile Liquid phase reaction T : 110°C P : 15 atm Conversion : 90% with selectivity of Pentenenitrile of 97% Catalyst : Ni and Tri (-o- Tolyl ) phosphite CH 2 =CH-CH 2 -CH 2 -C ≡N N ≡C-(CH 2 ) 4 -C≡N 4-Pentenenitrile Adiponitrile Liquid phase reaction T : 50°C P : 8 atm Conversion : 50% with 92% selectivity to ADN 1,3-Butadiene: CH 2 =CH-CH=CH 2 Structure of a  Herrmann's catalyst , which is derived from tris ( o- tolyl )phosphine Google image HCN HCN

165. Petrochemicals from Butene and Butadiene Chloroprene: CH 2 =CH-C=CH 2 Cl Chloroprene by chlorination of 1,3-butadiene Chloroprene : 3 rd place as industrially important monomer Polymer : Neoprene R (Stability towards Sunlight & Oil) Application : Many specialized uses such as roofing and flexible hose CH 2 =CH-CH=CH 2 + Cl 2 CH 2 =CH-CH-CH 2 Cl Cl + CH 2 -CH=CH-CH 2 Dilute Alkali, T: 85°C CH 2 -CH=CH-CH 2 + Cl Cl Cl Cl CH 2 =CH-C=CH 2 Cl 2-Chloro-Buta-1,3-diene c is-dichloro-2-butene trans-dichloro-2-butene 3,4-dichloro-1-butene

166. Petrochemicals from Butene and Butadiene Chloroprene: CH 2 =CH-C=CH 2 Cl Gas phase chlorination @ T:250°C Cis- dichloro-2-butene Trans-dichloro-2-butene 3,4-dichloro-1-butane Dehydrochlorination with dilute alkali sol n @ 85°C Chloroprene with a yield of 90-95% is attained Oxidation inhibitors are added to avoid polymerization of chloroprene

167. Petrochemicals from Butene and Butadiene 1,4-Butanediol: HO-(CH 2 ) 4 -OH 1,4-Butanediol by acetoxylation reaction of 1,3-Butadiene: 2 CH 2 =CH-CH=CH 2 CH 3 COOH 1,4-Diacetoxy-2-butene H 3 C-C-O-CH 2 -CH=CH-CH 2 - O-C-CH 3 1,4-Diacetoxy-2-butane + O 2 O O H 2 2H 2 O H 3 C-C-O-CH 2 -CH 2 -CH 2 -CH 2 - O-C-CH 3 O O HO-CH 2 -CH 2 -CH 2 -CH 2 - OH HO-CH 2 -CH 2 -CH 2 -CH 2 - OH Butane 1, 4-diol + 2CH 3 COOH T : 90-95°C P : 58 atm Catalyst : Pd and Te on active carbon BD conversion : 80-85% with a selectivity of 88% Acetoxylation reaction : (Acetic acid + Oxygen contained air) T : 66°C (zone 1) and 110°C (zone 2) P : 87 atm Catalyst : Pd active carbon BD conversion : complete conversion with 97% selectivity to butane derivative Hydrogenation reaction

168. Petrochemicals from Butene and Butadiene 1,4-Butanediol: HO-(CH 2 ) 4 -OH 1,4-Butanediol by acetoxylation reaction of 1,3-Butadiene: 2 CH 2 =CH-CH=CH 2 CH 3 COOH 1,4-Diacetoxy-2-butene H 3 C-C-O-CH 2 -CH=CH-CH 2 - O-C-CH 3 1,4-Diacetoxy-2-butane + O 2 O O H 2 2H 2 O H 3 C-C-O-CH 2 -CH 2 -CH 2 -CH 2 - O-C-CH 3 O O HO-CH 2 -CH 2 -CH 2 -CH 2 - OH HO-CH 2 -CH 2 -CH 2 -CH 2 - OH Butane 1, 4-diol + 2CH 3 COOH 1 st stage : 70% of diacetoxybutane is converted 2 nd stage: Rest of the diacetoxybutane is converted to 1,4-Butanediol Hydrolysis reaction

169. Upgrading C4 and C5 streams Steam cracking/FCC Naphtha C4 HCs: Butene-1, 2-Butane, Iso-Butylene C5 HCs: Olefins, Diolefins Naphtha grades Naphtha is a generic name given to light HCs boiling in the gasoline range (60-200°C) Light Naphthas < 100°C Intermediate Naphthas Heavy Naphthas > 150°C

170. Steam cracking Steam crackers are large and complex units at the heart of petroleum complexes producing important building blocks ethylene, propylene, butadiene, aromatics, and acetylene Raw materials to steam crackers: Naphtha, LPG, ethane, butane Hydrocarbon feedstock cracking in the presence of steam and a temperature of b/w 800-870°C Cracked gas separated into valuable products such as ethylene, propylene, acetylene, butadiene, and BTX Olefin’s reactivity and versatility is the reason for their tremendous growth/demand Cracking reaction https://www.sciencedirect.com/topics/chemistry/steam-cracking

171. Feedstock to Steam crackers

172. Steam crackers Schematics of a typical steam cracking furnace Feed : Mixture of Naphtha, LPG, ethane diluted with steam Reaction conditions : High temperature (~ 850°C); short reaction time; residence time in furnace reduced to milliseconds (supersonic gas velocities) Steam cracking furnaces : Process units consisting of: Coil bundle : Endothermic Cracking reactions take place Furnace : Provides heat to the coil (endothermic reactions) Radiant section : Coils placed in radiant section face 800°C temperature Convective section : Gas-gas heat exchangers utilized to preheat the feed Quencher : To stop the reaction to avoid the coke formation Steam cracking products: Ethylene, Propylene, Butadiene https://www.sciencedirect.com/topics/chemistry/steam-cracking EP0523762A1 Thermal cracking furnace and process

173. Upgrading of C 4 and C 5 cuts Large amounts of C 4 and C 5 compounds are produced along with ethylene in steam crackers and FCC Quantity and composition of C 4 and C 5 stream depends on the severity of the steam cracker operation and feedstock being processed C 4 and C 5 streams are important source of feedstock for: Oxygenates Synthetic rubber Chemical intermediates Typical C4 cuts from steam cracking contains Iso -Butane 2% Iso-Butene 26% 1-Butene 14% 1,3-Butadiene 3% 2-Butene 5% Cis-2-Butene 4% CH 3 -CH-CH 3 CH 3 CH 2 = C-CH 3 CH 2 =CH-CH 2 -CH 3 CH 3 -CH=CH-CH 3 Iso-Butane Iso-Butene 1,3-Butadiene 1-Butene 2-Butene CH 3 CH 2 =CH-CH=CH 2 https://www.accessengineeringlibrary.com/content/book/9781259643132/chapter/chapter25?implicit-login=true

174. Upgrading of C 4 and C 5 cuts Large amounts of C 4 and C 5 compounds are produced along with ethylene in steam crackers and FCC Quantity and composition of C 4 and C 5 stream depends on the severity of the steam cracker operation and feedstock being processed C 4 and C 5 streams are important source of feedstock for: Oxygenates Synthetic rubber Chemical intermediates Typical C5 cuts from steam cracking contains C 4 1% n-Pentene 26% Isopentane 24% Butene 12% Methyl cyclopentene 1.5% Isoprene 13.5% Pentadiene 9% Cyclopentadiene 7.5% CH 2 =CH-CH 2 -CH 2 -CH 3 CH 3 CH 3 -CH-CH 2 - CH 3 CH 3 -CH=CH-CH 3 CH 3 CH 3 CH 3 =C-CH = CH 2 CH 3 -CH=CH-CH=CH 2 n-Pentene Isopentane Butene Methyl cyclopentene Isoprene Cyclopentadiene 1,3-Pentadiene

175. Oxygenates (Alcohols and Ethers) Oxygenate compounds : Alcohols, Carboxylic acids, Ketones, Ethers and Phenols Only alcohols and ethers used as oxygenates in gasoline Oxygenates are ideal substitutes for aromatics in high performance gasoline Aromatics apart from being carcinogenic increase the formation of PM and the emission of unburned HCs which are responsible for photochemical contamination Oxygenates as gasoline pool objectives are: Increase the octane index Contributes to a more complete combustion in engine Reduces the exhaust emissions Reduces formation of CO up to 46% wt . w.r.t to a typical gasoline Significant savings in emissions of CO 2 , VOC’s and irregular emissions as aromatics (Benzene)

176. Oxygenates (Alcohols and Ethers) Oxygenates commonly used in Gasoline Component Formula ON Oxygen % wt. MTBE (CH 3 ) 3 C OCH 3 110-112 18 ETBE (CH 3 ) 3 C OCH 2 CH 3 110-112 16 TAME (CH 3 ) 2 C 2 H 5 C OCH 3 103-105 16 Streicher, C., Asselineau, L. and Forestiere, A., 1995. Separation of alcohol/ether/hydrocarbon mixtures in industrial etherification processes for gasoline production. Pure and applied chemistry, 67(6), pp.985-992.

177. Reactions: Oxygenate production CH 3 -C=CH 2 CH 3 + CH 3 -OH ↔ CH 3 -O-C-CH 3 CH 3 CH 3 (Iso-butene) (MTBE) CH 2 =C-CH 2 -CH 3 CH 3 + CH 3 -CH 2 -OH ↔ CH 3 -CH 2 -O-C-CH 3 CH 3 CH 2 ( Iso -Pentene) ( Ethy Tert -amyl ether) CH 3 Catalyst : Special cross-linked sulfonic acid resin catalyst Temperature: Reaction temperature is <100°C Etherification process (Liquid phase reaction): Sulfonic group

178. Process flow diagram for Oxygenate production 3 reactions taking place in fixed bed catalytic reactors: Etherification of branched olefins Selective hydrogenation of unwanted di-olefins Hydro-isomerization of olefin by double bond switch Hydro-isomerization transforms a molecule into different isomers in the presence of hydrogen and a catalyst. The functionalities of olefins, mainly for industrial and pharmaceutical purposes, vary by the location of CCDB on the alkene chains herein

179. Oxygenates: Overview Oxygenates can be used as ON enhancers to make low aromatics unleaded gasoline In early 90’s MTBE had majority of growth as the fastest-growing gasoline pool component High performance vehicle engines demanded high quality gasoline thereby there was a continuing need to increase ON of the refinery gasoline pool In late 90’s, US regulators phase outed MTBE from many markets in early 20 th century due to ground water contamination TAME and ETBE are also used as gasoline blending ethers Ethers are generally favoured over alcohols in gasoline blending for 2 reasons: Very low water solubility Low blending VP

180. Oxygenates: Alcohols vs. Ethers Alcohols Ethers Advantages: High blending ON Renewable (From fermentation of sugar/grain) Allow reduction of aromatics in gasoline Disadvantages: High blending RVP Expensive, overall energy inefficient Possible formation of formaldehyde on combustion Ground water soluble High concentrations increase NO x Advantages: Low blending RVP with high blending octane Better miscibility with gasoline than alcohols Low production cost Allow reduction of aromatics in gasoline Disadvantages: High concentrations increase NO x Possible ground water contamination Other health effects not clearly established Environmental benefits not proven Anselmi , P., Matrat , M., Starck , L. and Duffour , F., 2019. Combustion characteristics of oxygenated fuels Ethanol-and Butanol-gasoline fuel blends, and their impact on performance, emissions and Soot Index (No. 2019-01-2307). SAE Technical Paper.

181. Oxygenates: Alcohols versus Ethers Alcohol/Ether Wt.% O 2 VP (bar g) ON Methanol 49.9 4.1 117 Ethanol 34.7 1.3 114 MTBE 18.2 0.5 109 ETBE 15.7 0.3 110 TAME 15.7 0.2 105

182. Oxygenates: Chemistry Main reactions: CH 2 =C CH 3 CH 3 + CH 3 OH CH 3 -C-OCH 3 CH 3 CH 3 Iso-butene Methanol MTBE CH 2 =C CH 3 CH 3 + CH 3 CH 2 OH CH 3 -C-OCH 2 CH 3 CH 3 CH 3 Iso-butene Methanol ETBE

183. Oxygenates: Chemistry Main reactions: CH 3 CH=C CH 3 CH 3 + CH 3 OH CH 3 CH 2 -C-OCH 3 CH 3 CH 3 Iso -Pentene Methanol TAME Reactions are reversible and exothermic Conversions to ethers favoured by low temperature Acidic ion exchange catalyst used Typical reaction conditions 60 to 90°C around 14 atm Excessive temperature is not recommended because resin fouling can occur Reaction is conducted with a small excess alcohol relative to that required for the stoichiometric reaction Equilibrium is displaced towards the ether production to favour higher conversion per pass Production of high octane ether is maximized and production of lower octane oligomers is minimized Process temperature is more efficiently and securely controlled

184. Oxygenates: Chemistry Other reactions: CH 3 -C=CH 2 CH 3 + H 2 O CH 3 -C-CH 3 CH 3 OH Iso-Butene Water TBA CH 3 OH + CH 3 OH CH 3 OCH 3 + H 2 O Other side reactions: CH 3 -CH=CH-CH 3 + CH 3 OH CH 3 -C-CH 2 -CH 3 H O CH 3 Methyl Sec. Butyl Ether 2-Butene

185. Oxygenates: Chemistry Other side reactions: CH 3 -CH=CH-CH 3 + H 2 O CH 3 -C-CH 2 -CH 3 H OH Sec. Butyl Alcohol 2-Butene

186. H ülls one stage MTBE, ETBE, and TAME process

187. Polymerization: Polymer Gasoline Polymerization is an alternative to alkylation Olefin molecules (C 3 & C 4 ) are reacted together to produce larger olefins boiling in the gasoline range Polymerization produces about 0.7 barrels of polymer gasoline per barrel of olefin feed as compared with about 1.5 barrels of alkylate by alkylation The properties of polymer gasoline listed in the below table: Polymerization Alkylation RON 96-97 90 MON 82-83 89 (RON+MON)/2 89 90 RVP (bar g) 0.64 0.4

188. Polymerization: Reactions Reactions are exothermic Reaction mechanism is similar to that of polymerization of ethylene to polyethylene but conversion is low. Molecules formed are in the gasoline range and not macromolecule Catalyst used is phosphoric acid on an inert support (e.g. H 3 PO 4 acid mixed with K ieselguhr-natural clay)

189. Polymerization Process Sulphur in the feed poisons the catalyst Feed (propane, propylene, butylene, butane) is contacted with amine to remove H 2 S, caustic washed to remove mercaptan, water scrubbed to remove caustic and dried passing through molecular sieve bed Small amount of water (350-400 ppm) is added to promote ionization of the acid before olefin feed is heated and passed over the catalyst bed Both packed bed and tubular reactors can be used for temperature control ( heat of reaction removed in tubular reactors by steam generation) Polymerization operating conditions Temperature : 175-235 o C (usually 200-220 o C ) Pressure : 27-102 atm

190. Polymerization Process Propane and butane in the feed act as diluents and a heat sink to help control the rate of reaction and rate of heat release .

191. Polybutadiene Butadiene extraction process Extractive distillation C 4 -feed Distillation Propyne: CH 3 -C ≡CH 1,3-Buatadiene 1,2-Buatadiene Solvent degassing Rich NMP NMP Solvent recovery C 4 -acetylene: Vinyl acetylene CH 2 =CH-C ≡CH Regenerated NMP C 4 -vapor Crude butadiene Heavy fractions

192. Polybutadiene 1,3-Butadiene polymerization: CH 2 =CH-CH=CH 2 Polymerization --[--CH 2 -CH ≡ CH-CH 2 --] n -- 1,3-Butadiene obtained in the C 4 - cut stream from steam crackers 1,3-Butadiene is an important ingredient for petrochemicals 1,3-Butadiene used as a monomer for elastomers production (a) Polybutadiene rubber (b) Styrene butadiene rubber (c) Acrylonitrile butadiene rubber Polybutadiene rubber: Tires/Tyres production, Conveyor belt, Water hoses, G askets,Golf ball, Fuel in space shuttle

193. Solution polymerization Process description Polybutadiene rubber Solvents Heptane and Toluene Catalyst Ziegler-Nata catalysts system Tri-alkyl aluminium Nickel naphthalene Boron Tri-fluoride Reactor CSTR Conversion achieved 90-95% Feed composition (Vol %) 20% Monomer 80% Solvent Reaction Exothermic (NH 3 as heat extractor, (-33°C[-28°F])) Reaction sensitivity Moisture content of reactants

194. Fuel Additives Fuel additives are chemical substances added in small quantities for: Improving fuel performance properties Control fuel quality during production Control emissions Need for additives primarily due to: Lower fuel quality Greater engine demand Benefits of Additives use: Utilization of lower grade crude Enhanced fuel stability Fuel economy Drivability ease Longer engine life Lower exhaust emission

195. Fuel additives and their functions Additives and their functions Detergent and dispersant: Keep the engine clean, keep the sludge in suspension. Antioxidant : prevents formation of sludge and deposits; slows down the rate of oxidation of the hydrocarbons. Corrosion/Rust inhibitor: Prevents corrosion/rust on ferrous and non ferrous surfaces. Foam inhibitors: Minimizes foam formation. Lubricity additive: improves lubricity and reduces wear. Octane boosters: improves octane number of the gasoline.

196. Oxidation and anti-oxidation additives Hydrocarbon degradation process induced by: Oxygen Heat Metal surface, metal ions Irradiation (ultraviolet, daylight ) Impurities (e.g. free radicals from fuel combustion) May lead to: Viscosity increase Sludge formation Formation of organic acids leads to corrosion Foam Colour darkening