2_g valavarasu

HYDROTREATING/ HYDROPROCESSING OF NEW GENERATION CATALYSTS

Dr. G. VALAVARASUDeputy Manager (R&D)

Chennai Petroleum Corp. Ltd.

Simplified Flow Scheme of an Oil Refinery with Possible Locations of Hydrotreating Units

Why Hydrotreating/ Hydroprocessing?

• Refiners are faced with the need to convert heavy components of crude barrel into lighter, more valuable products. This situation is due to the following:

- Increasingly heavier crudes with high impurity levels (sulfur, nitrogen, metals etc)

- Lower demand for heavy fuel oils - Increasing market demand for gasoline, middle distillates (Jet

fuel, kerosene and diesel)- Environmental pressure to upgrade the quality of petroleum

fractions (Especially diesel and gasoline)- Improved engine designs requiring high quality fuels (high octane

gasoline, high cetane diesel)

Hydrotreating/ Hydroprocessing plays a pivotal role to meet the multiple challenges faced by today’s refining industry.

SPECIFICATIONS OF DIESEL

Characteristics

Euro- III

Euro-IV

Bharat-II

Bharat-

III

Bharat -

IV Density at 15oC, kg/m3

820-845

-

820-860

820-845

820-845

Kinematic Viscosity at 40oC, cSt 2.0-4.5 - 2.0-5.0 2.0-4.5 2.0-4.5 Flash Point, oC 55 - 35 35 35 Pour Point, oC, max., Winter - - 3 3 - Summer - - 15 15 - Cetane Number, min 51 51 48 51 51 Cetane Index, min 46 - - 46 48 RCR on 10% Residue, max. 0.3 - 0.3 0.3 0.3 Total Sulfur, wt.%, max. 0.035 0.005 0.05 0.035 0.005 Polycyclic Aromatic Hydrocarbon (PAH), wt.%, max. 11 11 - 11 11 Distillation, 85 vol.% Recovery at oC, max. - - 350 - - Distillation, 95 vol.% Recovery at oC, max.

360 360 370 360 360

SPECIFICATIONS OF GASOLINE

Characteristics

Bharat-II

Euro – III/ Bharat-

III

Euro – IV/ Bharat -

IV Density @ 15oC, gm/cc

0.710-0.770

0.720-0.775

0.720-0.775

RON, Min 88 91

91

MON, Min - 81

81

Sulfur, wt.%, max. 0.05 0.015

0.005

Benzene content, vol.%, max. 3.0

1

1.0

Olefin content, vol.%, max. - 21

21

Aromatics content, vol.%, max. - 42

35

Diesel Specifications – Need for Improvement Compound

Harmful Effects

Sulfur

• Increases emissions of SOx and nonmethane HC • Can lead to corrosion and wear of engine systems and thus

decreases relative engine life • Contributes to fine particulate emissions • Affects efficiency of exhaust after-treatment systems by sulfur

poisoning

Aromatics • Affect combustion and the formation of particulates and PAH emissions

• Influences flame temperature and NOx emissions

PAH • Increases engine deposits • Increases tailpipe emissions • Affects formation of particulates in the exhaust • Increases PAH emissions

Diesel Specifications – Need for Improvement

Compound

Harmful Effects

Cetane No

• Decreases engine crank time at a given engine speed • Reduces NOx, HC and CO emissions • Reduces fuel consumption • Reduces combustion noise

Density and Viscosity

• Reduces particulate emissions • Reduces particulate and NOx emissions from heavy duty engines • Increases fuel consumption and reduces power output • Reduces CO2 emissions

T95 • Reduces coking, tailpine emissions of soot/smoke/PM • Reduces NOx emissions • Reduces particulate matter

Gasoline Specifications – Need for Improvement

Compound

Harmful Effects

Sulfur

• Increases emissions of SOx and HC • Poisons the catalyst in catalytic converter and thus reduces its

efficiency • Affects ignition time and temperature and hence reductions its

efficiency across full range of air/fuel ratios

Olefins • Lead to deposit formation and increased emissions of reactive (ozone-forming) hydrocarbons and toxic compounds

• Thermally unstable and lead to gum formation and deposits in the engine’s fuel intake system

Aromatics • Increases engine deposits and tailpipe emissions including CO2

• Affects deposit formation, particularly in combustion chamber • Produces carcinogenic benzene in exhaust gas due to combustion

Benzene • A human carcinogen • Specification on Benzene in gasoline is the most direct way to limit

evaporative and exhaust emissions of benzene from automobiles

Gasoline Specifications – Need for Improvement

Compound

Harmful Effects

Octane

• Affects fuel consumption, drivability and power

Volatility • Increases vapour locking • Increases evaporative emissions • Affects ease of starting and good warm-up performance

T50 • Improves starting and warm-up performance • Affects vapour lock index

Salient Aspects of Hydrotreating/ Hydroprocessing

• Hydroprocessing technology could upgrade the heavy components of crude oil apart from improving the quality of fuels

• Hydroprocessing includes a variety of technologies to fulfill the following objectives:- Removal of heteroatoms (S, N, metals etc.)- Saturation of unsaturated hydrocarbons- Cracking of heavy hydrocarbons

• Hydrotreating is a catalytic reaction takes place in the presence of hydrogen at elevated temperature and pressure

Classification of Hydroprocessing

Hydrocracking Mild Hydrocracking Hydrotreatment

Fuels Lube

DistillateResid

Hydrodesulfurisation Hydrodenitrogenation

Hydrodemetalisation Hydrogenation

Hydroisomerisation

Hydroprocessing

Lube/Wax Hydrofinishing

Industrial Applications of Hydrotreating

• Naphtha Hydrotreating

- Pretreatment of reformer feed for removal of sulfur, metals- Selective desulfurization from FCC gasoline

• Hydrotreatment of Pyrolysis Gasoline

- Desulfurization and selective hydrogenation

• Kerosene/ Jet fuel Hydrotreating

- Desulfurization and Denitrogenation - Aromatic & Olefin saturation

• Diesel Hydrotreating

- Desulfurization and Denitrogenation- Aromatic & Olefin saturation- Hydrodewaxing

Industrial Applications of Hydrotreating

• Lube Oil/ Wax Hydrotreating

• Vacuum Gas Oil Hydrotreating

- Desulfurization- Denitrogenation- Demetallisation- Hydrogenation- Reduction of CCR

• Residue Hydrotreating

- Desulfurization- Denitrogenation- Demetallisation- Saturation- Reduction of CCR- Partial Cracking

Hydrotreating Reactions

Desirable Reactions

• Hydrodesulfurization (HDS)• Hydrodenitrogenation (HDN)• Hydrodeoxygenation (HDO)• Hydrodearomatization (HDA)• Saturation of olefins• Hydrodemetallation (HDM)

Undesirable Reactions

• Hydrocracking• Coking

Hydrodesulfurization

• Mercaptans, sulfides and disulfides are easiest to remove and converted tocorresponding saturated or aromatic compounds and H2S

• Sulfur combined into cycles of aromatic structure such as thiophenes, benzothiophenes, dibenzothiophenes and substituted dibenzothiophenes are more difficult to desulfurize

• Exothermic reaction • Consumes hydrogen

S

+ 6 H2 H2S +

Benzothiophene R R

Typical Sulfur Compounds Present in Fuels

Fuel Boiling Range in oC

Sulfur Compounds

Gasoline 25-225 Mercaptanes (RSH), Sulfides (R2S),Disulfides (RSSR), Thiophene and its alkylated derivatives, benzothiophene

Jet Fuel/ Kerosene

130-300 Mercaptanes, Benzothiophene, alkylated benzothiophenes

Diesel Fuel 160-380 Alkylated benzothiophenes , dibenzothiophenes, alkylated dibenzothiophenes

Hydrodenitrogenation

• Nitrogen compounds are removed as ammonia• Slower reaction than HDS• Exothermic reaction • Consumes hydrogen

N

+ 7 H2 NH3 +

QuinolineR R

Hydrodeoxygenation

• Fatty acids, naphthenic acids, alcohols, aldehydes and phenols are some are the organic nitrogen compounds present in fractions

• Organic oxygen compounds are removed as water• Water is later removed during stripping• Exothermic reaction • Consumes hydrogen

OH

+ H2 + H2O

R R

Hydrodearomatization

• Thermodynamic equilibrium limited • Exothermic and the number of molecules decreases• Favored by low temperature and high pressure

Polyaromatics Hydrogenation

+ 2 H2 + 3 H2

Naphthalene Tetralin Decalin

Monoaromatics Hydrogenation

R

+ 3 H2

R

Saturation of Olefins

• Olefins are not found in straight run fractions, but present in cracked stocks• Very rapid reaction • Highly exothermic • Consumes hydrogen

Hydrodemetallation

• Metals present as organo metallic compounds• Nickel and Vanadium compounds in crude oil concentrated in residue• Metals are adsorbed on the catalyst during hydrotreating• Results in catalyst deactivation and shortening of catalyst life

M-porphyrinH2

(H2S)MxSy + H-porphyrin

Hydrocracking

• Undesirable side reaction during hydrotreating• Breaking of longer hydrocarbons into shorter molecules in presence of

hydrogen• Consumes hydrogen• Reduces product yield• High temperature favors higher hydrocracking reaction

CmH2m+2 + CpH2p+2 [m+p= n]CnH2n+2

Coking

• Heavy molecules adsorbed on catalyst sites condense and polymerize to form carbonaceous deposit called coke

• Coke is more than 90% carbon• Reduces the catalyst activity by depositing on active sites• Regeneration of catalyst restores the original activity• Low temperature and high hydrogen pressure reduces coking reactions

Polyaromatics Alkylation Cyclization+ Olefins - H2 - H2 Coke

Precursors

Hydrotreating Process Schematic

Process Variables

• Reactor Temperature- Reactor temperature is an important operating variable to control HDT

reactions- Should be kept at optimum levels to limit undesirable reactions

• Hydrogen Partial Pressure- Results from operating pressure, hydrogen make-up and recycle rates

and purity- Higher pressure favors desirable reactions (HDS and hydrogenation) and

decreases undesirable reactions (Hydrocracking and coking)• Liquid Hourly Space Velocity

- Important process variable to control HDT reactions- Ratio of liquid feed rate to catalyst volume- Lower LHSV favors desirable reactions

• H2/Oil Ratio- Fixed considering the stability and life of catalyst

Typical Hydrotreating Conditions of Various Streams

Refinery Stream

Temperature, deg C

Pressure, kg/cm2

LHSV, h-1 H2/Oil Ratio, m3/m3

Naphtha 290-370 14-40 2-6 50-150

Jet Fuel/ Kerosene

315-360 20-40 1-3 100-250

Diesel 315-400 30-100 0.5-2 150-300

Vacuum Gas Oil

370-425 50-150 0.5-2 200-500

Residue/ Fuel Oil

380-450 80-200 0.5-1.5 200-800

Hydrotreating Catalysts

Catalysts play an important role in hydrotreating by means of enhancing the rate of specific reactions

Group VI B metals (chromium, molybdenum and tungsten) are active for desulfurization, especially when promoted with metalsfrom Group VIII (cobalt, nickel etc.)

The catalysts are usually supported on high surface area alumina(100-300 m2/g)

Hydrotreating Catalysts

CoO-MoO3/ Al2O3 and NiO-MoO3/ Al2O3 are the commonly used catalysts

NiW / Al2O3 is used for special applications

Molybdenum or tungsten is the active desulfurization component

Nickel or cobalt act as a promoter to increase catalyst activity

In certain applications such as aromatic saturation and cetane improvement, supported noble metals (Pt/ Pd) are employed in pure reaction environment

Activity Ranking of Sulfides and Sulfide Couples of Group VI-B and Group VIII metals

Hydrogenation of aromatics and olefins

Metals in zero valent state: Pt > Rh > Ni > Pd >Co (Aromatics)Rh > Pd >Pt >Ni > Co (Olefins)Pure sulfides:Mo > W >>Ni >CoSulfur Pairs at optimum:

Ni-W > Ni-Mo > Co-Mo > Co-W

Hydrodesulfurization Pure sulfides:Mo > W >> Ni > Co

Sulfide Pairs at optimum:Co-Mo > Ni-Mo > Ni-W > Co-W

Hydrodenitrogenation Pure sulfides:Mo > W > Ni > Co

Sulfide Pairs at optimum:Ni-Mo = Ni-W > Co-Mo > Co-W

The various pairs of non-noble metal sulfides that are possible, do not have the same activity for various conversions. The ranking of sulfides and sulfide couples of metals by order of activity is illustrated in the following table:

Chemical Composition of the Active Components

• Chemical composition plays a crucial role in determining the overall activity of the catalyst.

• For optimum conversions, the ratios of Group VI-B to Group VIII metals are always in the range of 0.25 – 0.40.

• Concentration by wt. of the metals is usually as follows:

» Co, Ni : 1 – 4 %

» Mo : 8 – 25 %

» W : 12 – 25 %

Catalyst Activation

• Hydrotreating catalysts are supplied in oxide form and these catalysts have to be activated before the start of the process.

• The active state of these catalysts which are mostly Mo, W, Ni, Co or a combination of these metals on alumina support is in the form of sulfides.

• Sulfiding of the catalyst is done as the activation step in the start-up procedure (In-situ presulfiding)

• Sulfiding is performed in the presence of liquid agents such as DMDS or with hydrogen sulfide gas

• Sulfidation is an exothermic process and therefore the procedure employed has a significant influence on the type of active sites generated and thereby on the catalyst activity and stability.

Typical Shapes of Hydrotreating Catalyst Particles

Typical Properties of Hydrotreating Catalysts

Property CoMo NiMo

Physical Properties

Shape Extrudate Trilobe Extrudate Trilobe

Diameter, mm 2.5 2.2

Length, mm 6.1 5.8

Surface area, m2/g 176 245

Pore volume, ml/g 0.51 0.39

Bulk density, kg/m3 750 850

Chemical Properties

MoO3, wt% 20.5 22.8

NiO, wt% 2.35 4.5

P, wt% 1.35 0.9

Na2O, wt% 0.05 -

Diesel Quality Improvements – Challenges

• Deepdesulfurization• Increase of Cetane number• Reduction of T95• Reduction of PAH

Reactivity of Various Organic Sulfur Compounds versus their ring sizes and positionsof alkyl substitutions on the ring (Song C., Catalysis Today)

The different types of S compounds in distillatesTypical S compounds Approximate content (ppm) in

SR diesel Cracked diesel

Reactivity over HDS

catalysts.

Sulfides; disulfides 5000 300 Moderate

Benzothiophenes (alkyl) (I) 1700 7300 Very easy

Non-beta-substituted

dibenzothiophenes (II)

1000 1900 Easy

Mono-beta substituted

dibenzothiophenes (III)

1500 2300 Moderate

Di-beta-substituted

dibenzothiophenes (IV)

600 900 Difficult

Other ring S-compounds 5500 2800 Moderate

Typical structures of the benzothiophene compounds:

SR

R S S SRR

RR

RR R

RR

(I) (II) (III) (IV)

Why is it difficult to desulfurize diesel to 50 ppm or less?

Due to the presence of sterically hindered S-compounds thatcannot adsorb easily on the CUS sites.

[Mobil, 1996]

Relative reactivity of different S compounds over HDS catalysts

SSCH3 CH3

S S

Slow Reaction

Fast Reaction

DMDBT

DBT

Adsorption Difficult

Adsorption Easy

CH3CH3

Schematic representation of the steric effect of methyl groupson adsorption of 4,6-DMDBT at CUS sites

Experiments carried out with pure 4,6-DMDBT suggest that it undergoes transformation in threedifferent ways over the complex catalysts:

S

R R

S

R

R R

S

R

RRR

H2

-H2S

-H2S Direct

-H2S

Dealkylation

R

4,6 DMDBT

DMDBT

Me DBT

DBT

DBT

Alkyl BT

Alk. DMDBT

Diesel feed; 15,000 ppm

Deep HDS40 ppm S

4,6 DMDBT

Alk. DMDBT

2500 ppm S4,6 DMDBT

DMDBT

4,Me DBT

PFPD analysis of Scompounds in differentdiesel oils

HDS

TECHNOLOGICAL OPTIONS TO IMPROVE THE QUALITY OF DIESEL

• Getting the most of existing units – Higher Reactor Temperature– Reducing Throughputs– Increasing Hydrogen Partial Pressure– Reducing Hydrogen sulfide Partial Pressure– Increasing H2/Oil ratio– Improved Reactor Internals

• Additional Reactor Volumes

• Catalyst Options

• New Technologies






• Development of new generation high activity HDS catalysts

Albermale STARS, NEBULA etc.Criterion CENTINELHaldor Topsoe TrimetallicNanoparticulate catalysts

ROLE OF R&D IN CLEAN FUELS PROGRAM

• Pilot plant evaluation of various feedstocks - diesel, gasoline, kerosene and lube oil base stocks

• Catalyst selection for various applications from pilot plant data• Optimization of operating parameters (Temperature, pressure, LHSV

and H2/oil ratio etc)• Data generation for kinetic modeling and simulation of DHDS,

catalytic reformer and hydrocracker units

R&D HYDROPROCESSING FACILITIES

• Hydrotreating Pilot Plant• High Pressure Reactor System• Catalytic Reformer Micro Reactor Unit• Parr Autoclave Reactor

HYDROTREATING PILOT PLANT

• Procured from Xytel India pvt limited, Pune during 1998• Designed for temperatures upto 550oC and pressures upto 250 kg/cm2

• Two reactors in series with 500 ml volume each • 5 zone electric furnace to maintain isothermal temperature profile• Liquid Flow Rate – up to 6 lit/h• H2 Rate – 600 SLPH• Hydrotreating/Hydrocracking/Isodewaxing studies can be carried out

in the unit using different catalysts and feedstock

HYDROTREATING PILOT PLANT

HIGH PRESSURE REACTOR SYSTEM

• Procured from Vinci Technologies, France during 1993• Designed for temperatures up to 600oC and pressures up to 300 kg/cm2

• Single reactor with 500 ml volume• 4 zone split type electric furnace to maintain isothermal temperature

profile• Liquid Flow Rate – up to 600 ml/h• H2 Rate – 30 - 300 SLPH• Hydrotreating/ Isodewaxing studies can be carried out in the unit using

different catalysts and feedstock

HIGH PRESSURE REACTOR SYSTEM

R&D ACTIVITIES – HDS OF DIESEL

• Pilot plant evaluation of different new generation high activitycatalysts for DHDS application to generate base data on their performance. These data will be useful during catalyst change over in DHDS unit

• Evaluation of indigenous DHDS catalyst samples

• Evaluation of different process technologies for the selection of suitable technology for DHDS or other applications

• Generation of kinetic data for various HDT reactions

New Generation Hydrotreating Catalysts – A Case Study

• CPCL has a DHDS unit with a capacity of 1.85 MMTPA to produce Bharat II and Bharat III diesel.

• The unit has two reactors in series

• For producing Euro IV diesel meeting 50 ppmw sulfur, it was decided to add additional high volume reactor in the existing unit with investment cost more than 100 crores

• Suggestion from CPCL R&D was sought from Dev./ PE


• CPCL R&D suggested the use of high activity catalyst in the existing unit in place of additional reactor facility to meet Euro IV diesel sulfur spec.

• CPCL R&D generates data base on new high activity HDT catalysts as part of its pilot plant evaluations

• By utilization of this data base on different new generation catalysts along with the use of in-house developed process model, CPCL R&D suggested the possibility of producing 50 ppmw sulfur in diesel by catalyst change over instead of opting new reactor with high investment cost.

Industrial Reactor Pilot Plant Reactor

Length 10 – 25 m 0.5 – 2.0 mDiameter 1 – 4 m 0.5 – 4.0 cmGas Velocity 14.8 – 2200 cm/s 1.48 – 220 cm/sLiquid Velocity 0.8 – 2.5 cm/s 0.08 – 0.25 cm/sWetting Complete PartialFlow Regime Trickle/Slug Flow TrickleAxial Dispersion Negligible Significant in some casesCatalyst Irrigation Very Good PoorMass Transfer Very Good PoorChanneling and Wall Effects Negligible SignificantMode of Operation Non-Isothermal Isothermal

Differences between Pilot Plant and Industrial Trickle Bed Reactors

Schematic Diagram of of Pilot Plant Reactor

Schematic Diagram of Trickle Bed Reactor Model

Gas Phase:

(For Pilot Plant Reactor Simulation – Where 0 mm ≤ z ≤ 900 mm)

⎟⎟⎠

⎞⎜⎜⎝

⎛−−= l

HH

Hp

lH

G

H CHP

akuRT

dzdP

2

2

2

2

2 … (A 1.1)

⎟⎟⎠

⎞⎜⎜⎝

⎛−−= l

SHSH

SHp

lSH

G

SH CHP

akuRT

dzdP

2

2

2

2

2 … (A 1.2)

⎟⎟⎠

⎞⎜⎜⎝

⎛−−= l

NHNH

NHp

lNH

G

NH CHP

akuRT

dzdP

3

3

3

3

3 … (A 1.3)

⎟⎟⎠

⎞⎜⎜⎝

⎛−−= l

HCHC

HCp

lHC

G

HC CHP

akuRT

dzdP

… (A 1.4)

Liquid Phase: For reactive zones

(For Pilot Plant Reactor Simulation – Where 250 mm ≤ z 700 mm)

{ ( )}sH

lHs

sH

lH

H

Hp

lH

L

lH CCakC

HP

akudz

dC2222

2

2

2

2 1−+⎟

⎟⎠

⎞⎜⎜⎝

⎛−= … (A 1.9)

{ ( )}sSH

lSHs

sSH

lSH

SH

SHp

lSH

L

lSH CCakC

HP

akudz

dC2222

2

2

2

2 1−+⎟

⎟⎠

⎞⎜⎜⎝

⎛−= … (A 1.10)

{ ( )}sNH

lNHs

sNH

lNH

NH

NHp

lNH

L

lNH CCakC

HP

akudz

dC3333

3

3

3

3 1−−⎟

⎟⎠

⎞⎜⎜⎝

⎛−= … (A 1.11)

( )sS

lSs

sS

L

lS CCak

udzdC

−−=1 … (A 1.12)

( )sN

lN

sN

L

lN CCk

udzdC

−−=1 … (A 1.13)

( )sO

lOs

sO

L

lO CCak

udzdC

−−=1 … (A 1.14)

( )sGO

lGO

sGO

L

lGO CCk

udzdC

−−=1 … (A 1.15)

( )sWN

lWN

sWN

L

lWN CCk

udzdC

−−=1 … (A 1.16)

( )sHC

lHC

sHC

L

lHC CCk

udzdC

−−=1 … (A 1.17)

( )sPoly

lPoly

sPoly

L

Poly CCkudz

dC−−=

1 … (A 1.18)l

( )sDi

lDi

sDi

L

lDi CCk

udzdC

−−=1 … (A 1.19)

( )sMono

lMono

sMono

L

lMono CCk

udzdC

−−=1 … (A 1.20)

( )

( )sMono

lMono

sMono

L

lMono

sNaph

lNaph

sNaph

L

lNaph

CCkudz

dC

CCkudz

dC

−=−=

−=

1

1

… (A 1.21)

Heat Balance Equation:

(For Industrial Reactor Simulation Operated Under Non-Isothermal Conditions)

( ) ( ) ( ) ( )

( ) ( ) ( )MonoMonDiDiPolyPoly

GOGOOONNSSR

pL

HrHrHr

HrHrHrHrdz

dTCu

Δ−+Δ−+Δ−

Δ−+Δ−+Δ−+Δ−=

ξηξηξη

ξηξηξηξηρ

… (A 1.22)

Across Liquid-Solid Interface:

( ) ⎟⎠⎞

⎜⎝⎛ ++++++++=− OHCWNGOMonoDiPolyNSB

sH

lHs

sH rrrrrrrrrCCak 32

23

222ηξρ

… (A 1.23)

( ) SBsS

lSs

sS rCCak ηξρ=− … (A 1.24)

( ) SBs

SHl

SHss

SH rCCak ηξρ−=−222

… (A 1.25)

( ) NBsN

lNs

sN rCCak ηξρ=− … (A 1.26)

( ) NBsNH

lNHs

sNH rCCak ηξρ

23

333−=− … (A 1.27)

( ) OBsO

lOs

sO rCCak ηξρ=− … (A 1.28)

( ) OBs

OHl

OHss

OH rCCak ηξρ−=−222

… (A 1.29)

( ) GOBsGO

lGOs

sGO rCCak ηξρ=− … (A 1.30)

( ) WNBs

WNlWNs

sWN rCCak ηξρ−=− … (A 1.31)

( ) HCBsHC

lHCs

sHC rCCak ηξρ−=− … (A 1.32)

( ) PolyBsPoly

lPolys

sPoly rCCak ηξρ=− … (A 1.33)

( ) DiBsDi

lDis

sDi rCCak ηξρ=− … (A 1.34)

( ) MonoBsMono

lMonos

sMono rCCak ηξρ=− … (A 1.35)

( ) NaphBsNaph

lNaphs

sNaph rCCak ηξρ=− … (A 1.36)

Kinetic Equations Based on Surface Concentrations of Reactants:

( ) ( )( )2,

2

2

2

1

1 sSHad

msH

msS

SappSCk

CCkr

+= … (A 1.37)

sNNkappN Ckr ,= … (A 1.38)

sOOappO Ckr ,= … (A 1.39)

( ) sGOGO Ckkr 21 += … (A 1.40)

sWN

sGOWN CkCkr 32 +−= … (A 1.41)

sWN

sGOHC CkCkr 31 −−= … (A 1.42)

sDiPoly

sPolyPolyPoly CkCkr −−= … (A 1.43)

sMonoDi

sDiDiDi CkCkr −−= … (A 1.44)

sNaphMono

sMonoMonoMono CkCkr −−= … (A 1.45)

Initial Conditions for the Simulation of Pilot Plant and Industrial Trickle Bed Reactor

⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜

⎝

⎛

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

=

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

0,

22

33

22

22

22

33

22

0,22

RR

lNaph

lNaph

lMono

lMono

lDi

lDi

lPoly

lPoly

lWN

lWN

lGO

lGO

lO

lO

lN

lN

lS

lS

lHC

lHC

lOH

lOH

lNH

lNH

lSH

lSH

lH

lH

HCHC

OHOH

NHNH

SHSH

HH

TT

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

CC

PP

PP

PP

PP

PP

At Reactor Inlet: At Reactor Outlet:

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Property Value

Density at 15 oC, gm/cc 0.8575Viscosity at 40 oC, cSt 3.90Pour Point, oC 0Aniline Point, oC 71Flash Point, oC 118Rams Bottom CarbonResidue, wt.%

0.1221

Sulfur, wt.% 1.11Nitrogen, ppmw 120Olefins, wt.% 6.1Total Aromatics, wt.% 37.40

Polyaromatics, wt.% 3.50Diaromatics, wt.% 10.10Monoaromatics, wt.% 23.80

Total Saturates, wt.% 62.60Naphthenes, wt.% 19.25Paraffins, wt.% 43.35

ASTM D-86 Distillation

IBP, oC 1645 vol.%, oC 234

10 vol.%, oC 24720 vol.%, oC 26430 vol.%, oC 27550 vol.%, oC 29470 vol.%, oC 31680 vol.%, oC 33190 vol.%, oC 350

FBP, oC 370

Properties of Diesel Feedstock

Experimental Data on the Effect of Liquid Hourly Space Velocity on Product Sulphur - Catalyst-A

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.5 1.0 1.5 2.0 2.5 3.0LHSV, h-1

Sulp

hur,

wt.%

TR - 320 oCTR - 340 oCTR - 360 oC

Catalyst - A

Experimental Data on the Effect of Reactor Temperature on Product Sulphur - Catalyst-A

0.00

0.05

0.10

0.15

0.20

0.25

0.30

310 320 330 340 350 360 370

Reactor Temperature, TR, oC

Sul

phur

, wt.%

Catalyst - A LHSV - 1.0 h-1

LHSV - 1.5 h-1

LHSV - 2.0 h-1

LHSV - 2.5 h-1

23 m3

17 m3

40 m3

135 m3

Schematic Diagram of Industrial Trickle Bed Reactors

Parameter Industrial ReactorOperating Point

Model Prediction % Deviation

Reactor Pressure, kg/cm2 44 44 -H2/oil Ratio 160 160 -Feed Rate, m3/h 270 270 -Reactor Temperature, oC 340 340 -Concetration in Reactor outlet:Sulfur, wt.% 0.0145 0.0156 -7.58Nitrogen, ppmw 38 42 -10.53Olefins, wt.% 3.0 3.01 -0.33Polyaromatics, wt.% 1.1 1.01 8.18Diaromatics, wt.% 6.0 6.22 -3.66Monoaromatics, wt.% 26.6 26.56 0.15Naphthenes, wt.% 19.5 19.29 0.15Wild Naphtha, wt.% 0.9 0.85 5.55Light Hydrocarbons, wt.% 0.1 0.11 -10.00

Simulation of Industrial Reactors - Model Prediction vs. Operating Data

Reactor Temperature, oC

290 310 330 350

Reactor Pressure, kg/cm2 44 44 44 44H2/oil Ratio 160 160 160 160Feed Rate, m3/h 270 270 270 270Concetration in Reactor outlet:

Sulfur, wt.% 0.0939 0.0383 0.0115 0.0035Nitrogen, ppmw 66 55 44 34Olefins, wt.% 3.61 3.33 3.06 2.79Polyaromatics, wt.% 1.46 0.84 0.74 1.50Diaromatics, wt.% 6.87 5.37 5.11 7.99Monoaromatics, wt.% 26.09 27.02 27.15 25.49Naphthenes, wt.% 19.28 19.30 19.31 19.29Wild Naphtha, wt.% 0.73 0.79 0.85 0.89Light Hydrocarbons, wt.% 0.06 0.08 0.11 0.14

Performance Prediction of Industrial Reactors with Catalyst-A and Catalyst-C:Effect of Reactor Temperature on Product Quality

Case 1: Catalyst-A in Reactor 1 and Catalyst-C in Reactor 2.

Reactor Temperature, oC

290 310 330 350

Reactor Pressure, kg/cm2 44 44 44 44H2/oil Ratio 160 160 160 160Feed Rate, m3/h 270 270 270 270Concetration in Reactor outlet:

Sulfur, wt.% 0.1935 0.0435 0.0158 0.0058Nitrogen, ppmw 68 57 46 35Olefins, wt.% 3.58 3.30 3.03 2.76Polyaromatics, wt.% 1.35 0.78 0.71 1.49Diaromatics, wt.% 6.52 5.08 4.95 7.96Monoaromatics, wt.% 26.26 27.14 27.23 25.50Naphthenes, wt.% 19.28 19.31 19.32 19.29Wild Naphtha, wt.% 0.72 0.78 0.84 0.88Light Hydrocarbons, wt.% 0.06 0.08 0.10 0.13

Case 1: Catalyst-A in Reactor 1 and Catalyst-C in Reactor 2.

Performance Prediction of Industrial Reactors with Catalyst-A and Catalyst-D:Effect of Reactor Temperature on Product Quality

Simulation of Industrial Trickle Bed Reactor - Effect of Feed Rate on Product Sulphur

0.00

0.01

0.02

0.03

0.04

0.05

0.06

200 220 240 260 280 300 320 340

Feed Rate, m3/h

Sulp

hur,

wt.%

Industrial Reactor Operating Point

TR - 330 oCTR - 340 oCTR - 350 oC

Reactor 1 - Catalyst AReactor 2 - Catalyst B

Simulation of Industrial Trickle Bed Reactor - Effect of Reactor Temperature on Product Sulphur

0.00

0.02

0.04

0.06

0.08

0.10

0.12

300 310 320 330 340 350 360

Reactor Temperature, TR, oC

Sulp

hur,

wt.%

Industrial Reactor Operating Point

Feed Rate - 250 m3/hFeed Rate - 270 m3/h

Reactor 1 - Catalyst AReactor 2 - Catalyst B

Temperature Profile of Industrial Trickle Bed Reactor System - Simulated

330332334336338340342344346348350352354356358360

0 50 100 150 200

Tem

pera

ture

, o C

Reactor 1 Bed 1

Reactor 1 Bed 2

Reactor 1 Bed 3

Reactor 2 Bed 1


• Simulations showed the possibility of producing diesel with < 50 ppmw sulfur in existing DHDS unit

• Based on R&D suggestion, it was decided to go for competitive bidding for selection of suitable high activity catalyst

• Three catalyst samples supplied by different vendors evaluated in pilot plant for their activity

• Based on catalyst activity, Grace Catalyst system was chosen for the unit

• The unit is running successfully for more than 3 years with production of < 50 ppmw sulfur

• MAKFining Premium Distillates Technology

– Mobil, Akzo Nobel, Kellog and Total Fina

• SYN Technologies– ABB Lummus, Criterion and Shell

Global Solutions

• MQD Unionfining - UOP

• Prime-D Technology - Axens

• Selective Adsorption– SARS by PSU

• Reactive Adsorption– S-Zorb by Philips Petroleum

• Oxidative Desulfurization– ASR by Unipure

• Biodesulfurization– Energy Biosystems


Novel Processes/TechnologiesRecently Commercialized Processes

SynSat/SynShift Process:• Uses catalysts developed by Criterion• Counter current flows of gas and liquid streams• Inter stage stripper to separate gas and liquid products• SynHDS for ultra deep HDS• SynSat/SynShift for Cetane Improvement, Aromatic saturation and T95 improvement

MQD Unionfining Process• Based on multifunctional catalysts optimized to achieve

varied product qualities• Latest HDS catalysts for ultra deep HDS• AS-250 catalyst for aromatic saturation• HC-80 and DW-10 catalysts for PP improvement

SARS-HDSCS Process• Being developed at PSU• Couples selective adsorption of organic sulfur compounds with HDS• More efficient for ULSD• Consumes less H2

ASR-2 Process• Produces ultra low sulfur fuels ( < 10 pppm) from a feed sulfur of 1500 ppm

(announced both for Gasoline and Diesel)• Based on oxidation chemistry and reactions are carried out at lower

temperature (100oC) and pressure (just enough to contain the vapour) • Uses H2O2 (oxidizing agent) and organic acid catalyst to convert sulfur

compounds to sulfones• Does not require H2 and fired heaters

Thank you

2_g valavarasu

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