variables,Reactor design concepts. Technology to Improve ......Heavy distillates makes more light ends from breaking more complex sulphur molecules Form of sulphur bonds Sulphur is

2/16/2015 NPTEL PHASE II :Petroleum Refinery Engineering

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Hydro treating process and catalysts Resid hydro processing,Effects of processvariables,Reactor design concepts.

Table:6.5

Technology to Improve HSD Quality[12,1719]

DHDS(35+bar pressure) When one sulfur reduction is required

DHDT(85+bar pressure) Large sulfur reduction & high cetane gain coupled with T95point improvement

Hydrocracker For middle distillate maximisation along with cetaneimprovement & very high sulfur reduction

Purpose

Hydrotreating[12]Remove hetero atoms and saturate carboncarbon bonds Sulfur, nitrogen, oxygen, andmetals removedOlefinic & aromatic bonds saturatedReduce average molecular weight & produce higher yields of fuel productsMinimal crackingMinimal conversion – 10% to 20% typicalProducts suitable for further processing or final blendingReforming, catalytic cracking, hydrocracking

HydrocrackingSevere form of hydroprocessingBreak carboncarbon bondsDrastic reduction of molecular weight50%+ conversionProducts more appropriate for diesel than gasoline

Hydroprocessing Trends[12,1718]

Hydrogen is ubiquitous in refinery and expected to increaseProduces higher yields and upgrade the quality of fuels

The typical refinery runs at a hydrogen deficitAs hydroprocessing becomes more prevalent, this deficit will increaseAs hydroprocessing progresses in severity, the hydrogen demandsincrease dramaticallyDriven by several factorsHeavier and higher sulfur crudesReduction in demand for heavy fuel oilIncreased use of hydrodesulfurization for low sulfur fuelsMore complete protection of FCCU catalystsDemand for high quality cokeIncreased production of diesel

Increased production of diesel[1720]

Catalystic ReformerThe most important source of hydrogen for the refiner



Continuously regenerated reformer: 90 vol%FCCU Offgas5 vol% of hydrogen with methane, ethane and propaneSeveral recovery methods (can be combined)CryogenicPressure swing adsorptionMembrane separationSteamMethane Reforming

Synthesis GasGasification of heavy feedHydrogen recovery – pressure swing adsorption or membrane separationMore expensive than steam reforming but can use low quality by product streams

Sources of Hydrogen[12,1516]

Catalytic ReformerThe most important source of hydrogen for the refinerContinuously regenerated reformer: 90 vol%Semicontinuously regenerated reformer: 80 vol%FCCU Offgas5 vol% hydrogen with methane, ethane and propaneSeveral recovery methods (can be combined)CryogenicPressure swing adsorptionMembrane separationSteamMethane Reforming

Synthesis GasGasification of heavy feedHydrogen recovery – pressure swing adsorption or membrane separationMore expensive than steam reforming but can use low quality by product streams

Reforming Endotherm catalystic reaction 750815°C

Shift Conversion.Exothermic fixed bed catalystic reaction 650°CGas purification.Absortion of CO2 in amine or hot K2CO3 solutionMethanation.Trace amount of carbon monoxide and carbon dioxide removed.Exothermicfixedbed catalystic reaction,700800°C

Table:6.6

Technologies to Improve MS Quality[12,1720]

Reformate Splitter Separation of Benzene rich light cut from rest ofreformate

Isomerisation Benzene Saturation & Octane increase

Continuos catalystic Reforming Octane increase



FCC Gasoline Spiltter Separation of light cut,mid cut & heavy cut

Selective desulpurisation Sulphur reduction Hydroprocessing Catalysts

HydrotreatingDesired function Cobalt molybdenum : sulfur removal and olefin saturation Nickelmolybdenum: nitrogen removal & aromatic saturationReactor configurationFixed bed – temperature to control final sulfur contentSelective catalysts for sulfur removal without olefin saturation Maintaining high octanerating

HydrocrackingCrystalline silica alumina base with a rare earth metal deposited in the lattice Platinum,palladium, tungsten, and/or nickelFeed stock must first be hydrotreatedCatalysts deactivate and coke does form even with hydrogen present Hydrocrackersrequire periodic regeneration of the fixed bed catalyst systems Channeling caused bycoke accumulation a major concern Can create hot spots that can lead to temperaturerunawaysReactor configuration Ebullient beds – pelletized catalyst bed expanded by upflow offluids Expanded circulating bed – allows continuous withdrawal of catalyst forregeneration

Hydrodesulfurization[12,3133]

SulfurSulfur converted to hydrogen sulfide (H2S) Added hydrogen breaks carbonsulfur bondsand saturates remaining hydrocarbon chainsForm of sulfur bonds Sulfur in naphtha generally mercaptans (thiols) and sulfides Inheavier feeds, more sulfur as disulphides and thiophenesLight ends Heavier distillates make more light ends from breaking more complex sulfurmolecules

Unsaturated carboncarbon bondsOlefins saturated – one hydrogen molecule added for each double bond Olefins prevalentin cracked streams – coker or visbreaker naphtha, catalytic cracker cycle oil, catalyticcracker gasolineAromatic rings hydrogenated to cycloparaffins (naphthenes) Severe operation Hydrogenconsumption strong function of complexity of the aromatics prevalent in heavy distillatehydrotreating, gas oil hydrotreating, hydrocracking

Selective catalysts available for hydrotreating cat gasoline for sulfur removal but not saturateolefins

Maintain high octane ratings

Hydrogen Consumption[12,1216]

Chemical consumption due to hydrogenation reactionsCracking reactions of carboncarbon bonds minimal in hydrotreating, even duringaromatic saturation

Hydrogen is lost in equilibrium with light gases



Amount is significant and may double amount required for sulfur removalHydrogen absorbed in liquid products

Usually small compared to sulfur removal needs – 1 lb/bblHydrogen removed with purge gas

Used to maintain a high purity of hydrogen — light ends dilute the hydrogenconcentrationUsually small compared to sulfur removal needs

General Effects of Process Variables[12,1216]

Reactor inlet temperature and pressureIncreasing temperature increases hydrogenation but decreases the number of activecatalyst sitesTemperature control is used to offset the decline in catalyst activityIncreasing pressure increases hydrogen partial pressure and increases the severity ofhydrogenation

Recycle hydrogenRequire high concentration of hydrogen at reactor outlet Hydrogen amount is muchmore than stoichiometric High concentrations required to prevent coke laydown &poisoning of catalyst Particularly true for the heavier distillates containing resins andasphaltenes

Purge hydrogenRemoves light ends and helps maintain high hydrogen concentration

Naphtha hydrotreated primarily for sulfur removalMostly mercaptans (RSH) and sulfides (R2S)Some disulfides (RSSR), and thiophenes (ring structures)

Cobalt molybdenum on alumina most common catalystChemical hydrogen consumption typically 50 to 250 scf/bbl

For desulfurization containing up to 1 wt% sulfur — 70 to 100 scf/bblSignificant nitrogen and sulfur removal — 250 scf/bbl

Naphtha Hydrotreating Process[12,1216]



Fig:6.10 Naphtha Hydrotreating Process

Liquid hourly space velocity ~ 2Hydrogen Recycle about 2000 scf/bblStripper overhead vapour to saturate gas plant

Recovery of light hydrocarbons and remove H2SFractionator Pentane/hexane overhead to isomerization

Bottom to reformer

Hyrdoprocessing Basics[12,1216,3133]

Fig:6.11 HydroProcessing Family

INTRODUCTION

Why Hydro processing ?Need to increase automotive fuel yield and qualityPetroleum fractions contain organic Sulfur, Nitrogen etc. which cause Increased air pollutionEquipment corrosionDifficulties in further processing (catalyst poisoning etc.)Stringent Government regulation for Sulfur in fuel.



What is Hydroprocessing[12,3135] Hydrotreating

Remove hertro atoms and saturation of carboncarbon bondsNitrogen,oxygen and metals removedOlefinic and Aromatic bonds saturatedReduced average molecular weight and produce higher yields of fuel products

Hydrotreating[12,3035]

Catalystic Hydrogenation process to remove contaminats(S,N,O) to upgrade fuel quality withnegligible effect on their boiling rangeAlso saturate olefins/aromatics to improve CetaneDegree of hydroprocessing depends uppon the nature of feedstock & extends of pollutantsremoval requiredUsed to upgrade Gasoline,Diesel and Lube base stocks.

Hydrotreating[12,3035]

Sulphur is converted to hydrogen sulphide H2SAdded hydrogen breaks carbonsulphur bonds & saturates remainining hydrogencarbonsCreates some light ends

Heavy distillates makes more light ends from breaking more complex sulphur moleculesForm of sulphur bonds

Sulphur is naphtha Mercaptans(Thiols) and sulfidesIn heavier feeds,more sulphur as Disulphides and Thiopenes

Nitrogen is converted to ammonia(NH3)Pyridines and Pyyroles are nitrogen containing compondsNitrogen removal minor in naphtha hydrotreatingAs the feeds become heavier denitrogenation becomes more significant,such as heavydistillate and gas oil hydrotreatingNitrogen removal requires about 4 times as much hydrogen as equivalents of sulphurremoval

Major Hydrotreating Reactions[12,3035] Removal of Hetro Atoms



Major hydrotreating reaction[12,3035]

HydrotreatingEffect of Process Variables[12,3035] Reactor inlet temperature and pressure

Increasing temperature increases hydrogenation but decreases the number of active catalystsitesTemperature control is used to offset the decline in catalyst activityIncreasing pressure increases hydrogen partial pressure and the increases the severity ofhydrogenation

Recycle Hydrogen Requires high concentration of hydrogen reactor outlet

Hydrogen amount is much more than stoichiometricHigh concentration require to prevent coke laydown and poisoning of catalystParticularly true for the heavier distillate containing resins and asphaltenes

Pure Hydrogen

Help to maintain high hydrogen concentration

Increases severity



Naphtha HydrotreatingDistillate(Light and Heavy) hydrotreatingGas oil hydrotreating

Fig:6.12 Hydrogen Consumption

Fig:6.13 HydroProcessing Catalyst share in Refinery

Hydrotreating Trends[12,24,3035] Trend is more hydroprocessing is driven by several factors :

Heavier and higher sulphur crudesReduction in demand for heavy fuel oilIncreased used of hydrodesulfurization for low sulphur fuels



More complete protection Of FCCU cactalystDemand of high quality coke

Fig:6.14 Catalyst in DHDS/DHDT Reactor



Fig:6.15 Catalyst in Hydrocracking Reactor

Challenges in HydroProcessing[12,3035]

Design of new catalyst formulation for :Diesel end point reductionSelective ring opening for cetane improvement with less hydrogen consumption

Design of improved reactor internalsProcess and catalyst for slurry reaction based hydroprocessing

Table:6.7

Reaction ChemistryIndicative Quality Changes

Reaction Hydrogen Density BoilingPoint Cetane

moles kg/m3°C Number

12 2 40 16.5 +10

123 3 110 28 +45

124 5 90 16.5 +30

Good Distributors

Decrease radial thermal distributionsIncrease volume for catalyst loading

Leading to

Increased cycle lengthHigher throughputIncrease conversionImproved product quality



Improved product consistency

Naphtha HydrotreatingHydrogen Consumption[12,3035]

For desulphurisation containing upto 1 wt% sulphur 70 to 100 scf/bblHigher nitrogen levels increase hydrogen consumption proportionatelySignifant nitrogen and sulphur removal250 scf/bbl

This is chemical hydrogen consumption

Add for mechanical loss and loss with the light hydrocarbon vapours



Fig:6.16 Naphtha HydrotreatingProcess

Naphtha Hydrotreating Process[12,3035]

Feed & hydrogen fed to furnaceVapors passed down flow over the catalyst bed

Outlet vapors about 370°COutlet cooled and flashed at 370°C to separate light ends

Exchange with feed(for heat integration)Final exchange with cooling waterSingle stage flash adequateBulk of flash gas recycled

Flashed liquid fed to stripper for removal of light ends of hydrogen sulphide and sour water

Distillate Hydrotreating

In general , all liquid distillate Streams contain sulfur compounds that must be removedneeds the treatment.Saturation of aromatics in diesel is essential to improve the cetane number.

Distillate HydrotreatingHydrogen Consumption[12,3035]

Light distillate hydrotreating (kerosene and jet fuel) requires more hydrogen than Naphthahydrotreating.

Heavy distillate (diesel) hydrotreating consumption quite variable

Can consume considerable quantities of hydrogen at higher severityHydrogen consumption and operating pressure are a function of the stream being treated,the degree of sulfur and nitrogen removal, olefin saturation, aromatic ring saturation,…..

Typical conditions – 300oC – 425oC ; 300 psig and greater Modest temperature rise sincereactions are exothermic

Hydrogen recycle rate starts at 2,000 scf/bbl;Consumption of 100 to 400 scf/bblConditions highly dependent upon feedstockDistillate (jet fuel & diesel) with 85% 95% sulfur removal

300 psig & hydrogen consumption of 200300 scf/bblSaturation of diesel for cetane number improvementover 800 scf/bbl hydrogen & up to 1,000 psig



Fig:6.17 Typical Distillate Hydrotreater for Base Metal Catalyst

Gas Oil Hydrotreating[12,3035]

Catalystic cracker feed stocks (atmospheric gas oil, light vacuum gas oil, solvent deasphaltinggas oil) hydrotreated severely Sulfur removal Opening of aromatic rings removal of heavymetalsDesulphurization of gas oil can be achieved with a relatively modest decomposition ofstructures Gas oils can be contaminated with resins and asphaltenes deposited inhydrotreater.Require catalyst replacement with a shorter run length than determined by deactivationGuard chamber may be installed to prolong bed life Nickel Molybdenum catalyst system fromsevere hydrotreating

Gas Oil Hydrotreating Process[12,3035]

Normally requires two reactors with two bedsEffluent from the second reactor is flashed in to two stagesHighpressure flash provides recycle of hydrogen gasLowpressure flash separates light ends for hydrogen sulfide recoveryLowpressure flash liquid is treated as gas oil and sent to catalyst crackerThe initial temperature is expected to be of the order of 350°CHydrogenation highly exothermiccare must be taken to avoid runaways

Hydrocracking Trends[12,3035] Hydrocracking does a better job of processing aromatic rings without cooking than catalysticcracking

Hydrogen reduced to hydrogenate polynuclear aromatics(PNAs)



Reduce the frequency of aromatic considensation

Hetroatom and metals prevalents in resins and asphaltenes poison hydroprrocessing catalyst

Feedstock selection is much more sophisticated than determination of CCR

Distribution of aromatic,naphthenic and paraffinic structure is important

Hydrocracking Feeds

Typical FeedsCat cracker "cycle oil"Cat cracker "cycle oil"Highly aromatic with sulphur,small ring and polynuclear aromatics,catalyst fines usuallyhas high vescosityHydrocracked to form high yield of jet fuel,kerosene,diesel & heating oil

Gas oil from visbreakerAromatic

Gas oil from delayed cockerAromatic olefinic with sulphur

Residue Hydrotreating[12,3035] Residuum technology is widely used for pretreating residuum to produce RFCC feed,hydrotreatingcoker feed,hydrotreating visbreaker/FCC feed or to produce Low sulphur Fuel Oil(LSFO)Most new residuum hydrotreating units pretreat for an RFCC,allowing a very high conversion tohigh value product with this combined processingThe RDS process reduces metals,sulphur,nitrogen and carbon residue in the residuumBy pretreating the residuum with an RDS,the yields and quality of RFCC products are greatlyimproved Residue Hydrocracking This technology provides the means to convert residuum to lighter petroleum fraction such asnaphthna and distillates are greater than 70% conversion of heavy residual 975° F (524° C)materialThe unconverted residue is usually blended as fuel oil as if the conversion is less than 80%Conversion greater than 80% & as high as 97% has been achieved commercially but theunconverted residue may be unstable as a fuel oil blend stockAlong with high conversion,feed desulphurization of 8085% is typical for most designs Hydrotreating of Diesel[12,3035] Unionfining Fixed bed catalysic process developed by UOPAdopted for diesel HydrodesulphurizationKey Features

Operates at about 36 Kg/cm2

Operates at about 360400°C temperature



Hydrogen is consumedHeat is releasedProducts are saturatedProducts are nearly free of hetero atoms(S,N,O)

HYDROTREATING FLOW SHEET[12,3035]

Fig:6.18 Hydrotreating Flow Sheet

DHDS Process Variable[12,3035]

Some important process variable affects the catalyst stability and product qualityThese variable needs to be monitored regularly for consistent operation & longer cycle lengthThe Process Variables :

Reactor temperatureFeed rate qualityLiquid Hourly Space VelocityRecycle gas rateH2S partial pressure

DHDS Process Variable Reactor Temperature

Temperature of the reactor effluent is more than that of the reactor inlet streamThe hydesulphurisation reaction are exothermicThe reactor temperature is most vital control parameterBest way to control reactor temperature is to control WABT by adjusting quench flowIncreasing reactor temperature increases severity of reaction of constants like H2 partialpressure



Higher reactor temperature causes more hetero atom(S,N,O) removal and saturationHigher reaction leads to higher catalyst deactivation (more coke deposit) and lower cycletime of plantHigher reactor temperature may have adverse impact on treated diesel color stability

Feed Quality & Rate

DHDS feed streams are SR Gas oil,LCO from FCCU,gas oil from CIDW,kerosene cuts etc.Straight run components are easier to treatCracked product /unsaturated are difficult to process as they require more heat duringreactionRegular monitoring of SG,sulphur contents of feed is vitalHigher S content in feed requires more severity,H2 consumption and H2S reaction

Liquid hourly space velocity is defined as M3/Hr of feed (at 15°C)per M3 of catalystDesign value of LSHV depends upon feed stock quality,product quality stipulation andchanneling that may occur inside reactor,leading to unusual deactivation of catalyst bedOperate near design value,do not go below trundown ratio

H2 Partial Pressure[12,3035]

This is the design criteria and critical process variable for good hetero atom(S,N,O) removalIt is defined as System Pressure * H2 PurityLower H2 partial pressure reduces reaction rateLower H2 partial pressure increases rate of coke deposition on catalystLower H2 partial pressure leads to higher reactor temperature the (S,N,O)removal andreduce cycle length

Recycle Gas Rate Higher Recycle Gas Flow Rate Helps in

Supplying excess H2 is to ensure reaction completionAbsorbing heat of reaction to control bed temperatureEnsuring good linear velocity in heater and exchange to control temperatureAnother related process variable is gasto oil ratio and has same effect.It is defined as Totalgas flow(NM3/Hr)/Feed rate(NM3/Hr)at 15°C

Hazards of Hydrogen[12,1316,3035]Hydrogen gas is colorless and odorless and not detectable by human senses Properties of Hydrogen What Is Hydrogen?Hydrogen is a colorless, odorless, tasteless, flammable nontoxic gas. It is the lightest of all gases,with a specific gravity of 0.0695. The hydrogen content of atmospheric air at sea level is 0.5 ppm.Hydrogen has two isomers (forms): orthohydrogen, in which the two atomic nuclei spin in thesame direction; and parahydrogen, in which they spin in opposite directions. There is nodifference in the chemical properties of the two forms of hydrogen, but there are slight differences



in physical properties. Gaseous hydrogen is a mixture of 75% orthohydrogen and 25% parahydrogen at room temperature; this mixture is called normal hydrogen (CGA G5 1991). Hydrogen Has Unique Properties[12,1316]Several unique properties contribute to the hazards associated with gaseous and liquid hydrogensystems:

Hydrogen is flammable over a wide range of concentrations.The ignition energy for hydrogen is very low.A single volume of liquid hydrogen expands to about 850 volumes of gas at standardtemperature and pressure when vaporized. At 7,000 ft elevation, this expansion rate isincreased to approximately 1,000 volumes of gas at standard temperature.Hydrogen is able to reduce the performance of some containment and piping materials, suchas carbon steel.

Properties of Hydrogen continued[1316] FlammabilityHydrogen burns with a nearly invisible bluish flame, unless it is contaminated with impurities, inwhich case a paleyellow flame is easily visible in the dark. The temperature of burning hydrogenin air is high 2050 oC (3,713 oF), as compared with 1250 oC (2,276 oF) for gasoline), and warmhydrogen gas rises rapidly because of its buoyancy. Hydrogen forms a flammable mixture over awide range of concentrations in air and requires a minimum ignition source, only onetenth of theenergy required for gasoline vapors. It is the combination of these factors that contributes to theflammability hazard associated with hydrogen gas. (See the table below for a summary of thephysical properties of hydrogen.) EmbrittlementBecause of its small molecular size, hydrogen can easily pass through porous materials and iscapable of being absorbed by some containment materials, which can result in loss of ductility orembrittlement. At elevated temperatures, this process is accelerated. Because of the possibility ofhydrogen embrittlement of some materials, piping and component materials that are not subjectto this form of degradation should be selected.Recommended materials include 300seriesstainless steels, copper, and brass. Properties of Hydrogen continued The following table lists the physical properties and characteristics of hydrogen and their values.

Table:6.8

Physical Properties and Characteristics of Hydrogen

Property/Characteristic Values(approximate)Color NoneOdor NoneToxicity Nontoxic

Density/Liquid(boiling point) 4.4lb/ft3 (0.07 g/cm3)Boiling Point(1atm) 423.2 F (252.9°C)

Critical Temperature(188.2 paisa) 400.4 F(240.2°C)stoichiometric mixture in air 29 vol %Flammability limits in air 475 vol %



Detonation limits in air 1860 vol %Minimum ignition energy in air 20 ujAutoignition temperature 1,085 °F(585 °C)

Volume Expansion

Liquid(252.9°C) to gas (252.9°C)

gas(from 252.9°C to 20 °C)

liquid(252.9°C)to gas (20°C)

1:53

1:16

1:848

Hazards of Hydrogen[1316,36] Flammability and Explosivity are Primary HazardsThe primary physical hazards associated with hydrogen gas are its flammability and explosivity.This is because hydrogen can form a flammable mixture with air over a wide range ofconcentrations (4%Ð75%), and very low energy is needed to ignite hydrogenair mixtures. Oncehydrogen is ignited, the reaction can proceed either by deflagration (subsonic propagation) ordetonation (supersonic propagation). Deflagration in a closed volume can cause a pressureincrease of almost eight times the initial pressure. Detonation from a lowenergy ignition source ispossible in hydrogenair mixtures of 18 to 60% vol% that are well mixed and confined. Althoughhydrogen air mixtures have the same calorific value per pound as TNT, the rate of energyrelease is much slower for hydrogenair mixtures.Hydrogen detonations, although rare, are characterized by pressure increases so rapid thatpressurerelief devices are usually ineffective. When using hydrogen in enclosed areas, consultNational Fire Protection Association documents 68 and 69. Effects on HealthHydrogen is nontoxic and has even been used as a filler for oxygen sources for underwater diving.The primary health effect associated with hydrogen is the possibility that it could displace air in apoorly ventilated or confined space, resulting in asphyxiation. However, because it is flammable atonly 4% in air, the most significant concern should be the physical hazard of flammability and thepossibility of burns resulting from fires and explosions. When working with liquid hydrogen, thereis an additional health hazard of cryogenic burns.

Table:6.9

Flammability Limits

Hydrogen Propane

LFL 4.1% 2.1%

UFL 75% 9.5%

Explosive Limits

LEF 18.3 UEL 59

Average velocity in air at 20°C

Hydrogen Oxygen



39MPH 10MPH

Auto ignition temperature °C

Hydrogen Propane

400 450 An invisible spark or static spark from a person can cause ignition

Hydrogen therefore easily ignited and burns rapidlyHydrogenpure air flames are colorlessColorless Hydrogen flames can cause severe burnsFor occuptional exposure H2 is classed as as aphyxiant

References

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2. James H. Gary and Glenn E. Handwerk (2001). Petroleum Refining: Technology andEconomics (4th ed.). CRC Press. ISBN 0824704827.

3. Beychok, Milton (May 1951). "Algebraic Solution of McCabeThiele Diagram". ChemicalEngineering Progress.

4. Seader, J. D., and Henley, Ernest J. (1998). Separation Process Principles. New York: Wiley.ISBN 0471586269.

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submitted to Eindhoven University of Technology, The Netherlands, 2002.9. Hagen, J. Industrial catalysis a practical approach. WILEYVCH Verlag GmbH & Co. KGaA:

Weinheim, 2006.10. Cejka, G.; Corma, A.; Zones, S. Zeolites and Catalysis Synthesis, Reactions and Applications.

WILEYVCH Verlag GmbH & Co. KGaA: Weinheim, 2010.11. Szostak, R. Molecular Sieves: Principles of Synthesis and Identification. Thomson Science,

Division of International Thomson Publishing: UK, 1989.12. Mohanty, P., Pant, K.K., Parikh, J., Sharma, D.K. (2011) Fuel Process. Technol. 92, 600

608.13. Mohanty, P., Pant, K.K., Naik, S. N., Das, L. M., and Vasudevan, P. (2011) ‘Fuel production

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16. Mohanty, P., Patel, M., Pant, K. K. (2012) Sustainable hydrogen from steam reforming ofacetic acid as a model oxygenate over CuZn supported calcium aluminate catalyst.Bioresources Technology 123, 558565.

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hydrocarbons, Catalysis Today, 96, 155160.21. Reza Sadeghbeigi (2000). Fluid Catalytic Cracking Handbook (2nd ed.). Gulf Publishing. ISBN

0884152898.22. Kister, Henry Z. (1992). Distillation Design (1st Edition ed.). McGrawHill. ISBN 007

0349096.23. Karl Kolmetz, Andrew W. Sloley et al. (2004), Designing Distillation Columns for Vacuum

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McGrawHill. ISBN 0070494797.30. Felder, R., Roussea, W. (2005). Elementary Principles of Chemical Processes (3rd ed.). Wiley.

ISBN 9780471687573.31. http://en.wikipedia.org/wiki/Hydrodesulfurization.32. http://alexandria.tue.nl/extra2/200000973.pdf.33. http://www.cbi.com/technologiesservices/hydrodesulfurization/34. http://www.kbr.com/Technologies/Refining/Hydroprocessing/35. http://www.uop.com/products/catalysts/hydrotreating/36. http://www.usmra.com/repository/category/mine_gases/hydrogengassafety.pdf

Documents

variables,Reactor design concepts. Technology to Improve ......Heavy distillates makes more light ends from breaking more complex sulphur molecules Form of sulphur bonds Sulphur is