S_Bose

7/31/2019 S_Bose

1/44

11

APPROACH TO

REFINING PROCESSES

7/31/2019 S_Bose

2/44

THE FIRST STILL LIES STILL

Beginning of Petroleum Refining in India

In 1890s Crude Oil used to be

distilled in DIGBOI in CastIron pans called Stills.

Bottom portion of one such

still of 9 feet dia is still kept atDigboi Refinery.

A refinery was commissionedin 1901 at Digboi with 500Barrels per Day capacity

7/31/2019 S_Bose

3/44

OUTLINE1. Introduction

2. Physic a l Proc esses

3. Thermal Proc esses

4. Ca ta lytic Proc esses

5. Conversion of Heavy Residues6. Trea tment of Refinery Gas Streams

7/31/2019 S_Bose

4/44

INTRODUCTION

Oil refining is a key ac tivity in the CPI.

Over 600 refineries worldwide have a tota l

annual c apac ity of more than 3500 x 10 6

tonnes.

Goal of oil refining is mainly twofold:i. produc tion of fuels for transportation, power

generation and hea ting; andii. produc tion of raw materials for the CPI.

Oil refineries are c omplex plants, but arerela tively mature and highly integra ted .

7/31/2019 S_Bose

5/44

Overview

After desalting and dehydration , c rude issepara ted into frac tions by distillation .

The distilled frac tions c an not be used direc tly.The reason for suc h a c omplex set ofproc esses is the d ifferenc e between the c rudeoil properties and the needs of the m arket.Another reason for c omplexity is

environmental . Legisla tion demands c leanerproduc ts and is the m ajor drive for proc essimprovement and develop ment of novel

processes.

7/31/2019 S_Bose

6/44

COMPLETE REFINERY

CrudeOil

Jetty / Pipeline

OM&S SeparationUnits

ConversionUnits

OM&S(Intermediates)

OM&S (Product Blending &Dispatch)Finishing

Units

MarketingQualityControl

Power &Utilities

Welfare / Admn.

Waste

Treatment Round the clock operation

7/31/2019 S_Bose

7/44

Physic a l and Chemic a l proc esses

ChemicalPhysical

Thermal CatalyticDistillationSolvent extra c tion

Prop a ne d ea sp ha ltingSolvent d ewa xingBlending

VisbreakingDela yed c oking

Flexic oking

HydrotreatingCa ta lytic reforming

Ca ta lytic c ra c kingHydrocrackingCa ta lytic d ew a xingAlkylationPolymerizationIsomerization

7/31/2019 S_Bose

8/44

Flow sc heme of a modern refinery

7/31/2019 S_Bose

9/44

Desalting/ dehydra tion

Crude o il often c ontains wa ter, inorganic sa lts , suspendedsolids, and wa ter-soluble trac e metals.Step 0 in the refining proc ess is to remove these c ontam inantsso as to red uc e c orrosion , p lugg ing, and fouling of eq uipment

and to p revent poisoning c a talysts in proc essing units.The typ ic al method of c rude-oil desalting is electrostaticseparation.

In desa lting, waterand c hemic alsurfactant(demulsifiers) aread ded to the c rude ,whic h is hea ted so thatsa lts and otherimpurities d issolve ora ttac h to the wa ter;

then held in a tank tosettle out .

7/31/2019 S_Bose

10/44

Desalting/ dehydra tion

The c rude oil feedstoc k is heated to 110 150 C toreduc e visc osity and surfac e tension for easier mixingand separa tion of the water. The tem pera ture is limitedby the vapor pressure o f the c rude o il.High-voltage elec trosta tic c harges are a pplied a t thesettling tank to c onc entra te suspend ed wa ter g lob ulesin the bottom of the settling tank .

7/31/2019 S_Bose

11/44

Crude d istilla tionStep 1 in the refining proc ess is the separa tion of c rude oilinto va rious frac tions or stra ight-run c uts by d istillation. Themain frac tions or "cuts" ob ta ined have spec ific boiling-point ranges and c an be c lassified in order of dec rea singvolatility into g ases, light distilla tes, middle d istillates,hea vy vac uum distilla tes and residuum.

The desalted c rude feedstoc k is prehea ted usingrec overed proc ess hea t.The feedstoc k then flows to a d irec t-fired c rude chargeheater then into the vertic a l distilla tion c olumn just ab ovethe bottom , a t pressure slightly a bove a tmospheric and a t

tem pera tures rang ing from 340-370C (above thesetem pera tures undesirable thermal c rac king may oc c ur ).All but the heaviest frac tions flash into vapor a t the feed-entry loc a tion of the c olumn.

7/31/2019 S_Bose

12/44

Liquid and vapor flows in a tray c olumn

7/31/2019 S_Bose

13/44

Crude d istilla tion

Unc ondensed vapours lea ve c olumnoverhead, are c ondensed outside a ndstored in overhead ac c umulator drum.Part of this liquid is refluxed ba c k to thec olumn a t top , and part is withdrawn a sthe top frac tion.Heavy residuum is d rawn out fromc olumn bottom.To furthe r d istill the residuum from thea tmospheric tower, without thermalcracking, reduc ed pressure is required .

As the ho t vapor rises in the tower, portions of the vapor a rec ondensed a t suc c essively higher stag es in the tower, andthe various produc ts e.g ., d iesel, ke rosene, gasoline aredrawn off as liquids (through side-draw strippers).

The proc ess takes p lac e in vacuum distillation tower. The princ iples

of vac uum distilla tion are same, exc ep t that larger diam eterc olumns a re used to m ainta in c om parable va por veloc ities a t thereduc ed pressures.

7/31/2019 S_Bose

14/44

At mospheric & Vacuum Dist il lat ion Unit

Crude Oil

P r e - t

o p p i n g

HGO

LGO

Kero / ATF

Heavy Naphtha

Light Naphtha

RCO

A t m o s p h e r i c

LPG

Stabilized Naphtha To Steam Ejector

VR

Vac Slop

LDO

LVGO

HVGO

V a c u u m

S

T

A

B

Desalter

UnstabilisedNaphtha

T=130-140Deg C

T= 200 Deg C

T= 370 o C

T= 415 oC

Pr= 40-60 mm Hg a

Furnace

Furnace

7/31/2019 S_Bose

15/44

Streams from Atm. Distillation

Crude

oil

Strea m b .p .,o C

Application KeyProperty

Trea tment

Gas Refinery fuel H 2S Aminescrubbing

LPG Domestic / Industrial fuel

Cu c orrosion,Weathering

Causticwash,Merox

Naphtha 30 140 MS blend ,

feed forPetrochemical / fertilzer

Cu c orrosion ,

Componentanalysis(PIONA)

Catalytic

reforming / isomeriz-ation

Kerosine / ATF

140 270140 240

Dom estic fuel / Jet fuel

Smoke p t. / Freeze p t.,

Ag c orr.

Merox / Hydro-

treatment

Gas Oil 240 370 Diesel fuel S c ontent,Cetane no.

Hydro-treatment

Red uc edcrude > 370 Furtherconversion,Furnac e Oil

Vacuumdistillation

7/31/2019 S_Bose

16/44

Catalyt ic Reforming React ions

7/31/2019 S_Bose

17/44

Semi- regenerat ive Cat alyt ic Reforming UnitFlow Scheme

7/31/2019 S_Bose

18/44

Effect of process var iables on Reforming

l f

7/31/2019 S_Bose

19/44

Cont inuous Catalyt ic Reforming UnitFlow Scheme

NHDT

LSRN (85-160)

VBN

Off Gas to

FG system

SEPARATOR

H2 RICHGAS TO PSA

Off Gas to

FG system

LPG

STABILIS

ER

Reformate to MS Poolvia RSU

COL OVHDRECEIVER

RGC

T=520-540 Deg C

Pr. 17.0

kg/cm2g

Pr. 17.0kg/cm2g

Regenerator

Recontacting drum

T =-10 deg c

7/31/2019 S_Bose

20/44

Diesel Hydro Desulphurisation (DHDS) Unit

Reactor

Fuel gas

H2 Recycle

H2 MakeUp

High Pr.Separator

DesulphurizedDiesel

Wildnaphtha

FeedFurnace

S

T

R

I

P

P

ER

Off. gas

COL OVHDRECEIVER

Steam

Temp. 350Deg C

Pr. 35-40kg/cm2g

Lean Amine

Rich Amine

A bsorber

7/31/2019 S_Bose

21/44

DHDS / DHDT :Produc t Yields & Opera ting Conditions

1. Typic al Product Yields, wt.% on feed

No. Produc ts DHDS DHDT End Use

1. Off Gas 1.4 1.8 Refinery Fuel Gasafter Amine Wash

2. Wild

Naphtha

1.3 2.0 Naphtha a fter

stabilization3. Diesel 97.2 96.1 Diesel Pool

2. Typ ica l Opera ting Conditions

DHDS DHDT

Tempera ture, o C 340 390 330 370

System Pressure, kg / c m 2(g) 40 50 90 105

7/31/2019 S_Bose

22/44

Sec ondary proc essing of VDU streamsNo VDU Product Quality Processing

1. VGO & SO High S. LowCetane no.

Hydrotreatment (DHDT) for Sulphur andCetane No./ LOBS

2. LO High S. HeavyHydrocarbons

Fluid Ca talytic Crac king (FCC) unit / Hydro-Crac king Unit(HCU) / LOBS

3. IO High S. HeavyHydrocarbons


4. HVGO High S. HeavyHydrocarbons


5. Vac uum Slop HeavyHydrocarbons,Fuel oil Produc t

Visbrea ker unit / Coker/ Fluid Ca talyticCrac king (FCC) unit

6. Vac uumResidue

Residue Bitumen Blowing Unit / VBU / Coker/ Propane De-Asphalting (PDA) unit

7/31/2019 S_Bose

23/44

Lube Base Oil Proc essing

Crude Selec tion

Multi-step manufac turing proc ess

7/31/2019 S_Bose

24/44

BASE OIL COMPONENT PROPERTIES

PROPERTYN-

PARAFFINSISO-

PARAFFINSNAPHTHENES AROMATICS

VI HIGH HIGH MEDIUM LOW

POUR PT HIGH LOW LOW LOW

OXIDATION

STABILITYGOOD GOOD FAIR LOW

THERMALSTABILITY

GOOD GOOD FAIR LOW

b l h l h

7/31/2019 S_Bose

25/44

A t m o s p

h e r i c d

i s t i l l a t i o n

Crudeoil

V a c u u m

d i s t i l l a t i o n

H y

d r o

f i n

i s h i n g

Propane De- Asphalting

Gas

NaphthaKeroDiesel

RCO

VR DAO

VacuumDistillates

WaxyRaffinate

De-waxedoils

Group ILOBS150N

500N

HNBN/150BS

VGO

Properties controlled by Process UnitsKV,

Flash Point VI, CCR Pour PointColour &Stability

Lube Base Oil Proc essing Philosophy

SolventDewaxing

Unit

S o

l v e n t

E x

t r a c

t i o n

( F u r f u r a

l & N M P )

CatalyticDewaxingUnit

Group II LOBS

100N150N500N

150BSH2

H2

VI,Pour Point,Colour&Stability

EXTRACTION UNIT

7/31/2019 S_Bose

26/44

EXTRACTION UNIT

Feed stoc k : - Vac . Distillatesex VDU

- DAO ex PDA

Purpose : Extrac tion ofaromatic s using Furfura l assolvent to improve VI of

LOBS.Products : - Raffinate

- Aroma tic extrac t.

Quality Monitoring :Raffina te: K.V (100 oC), RI,

Extrac t : Density.

FURFURAL EXTRACTION SCHEME

7/31/2019 S_Bose

27/44

FURFURAL EXTRACTION SCHEME

WASTE WATER

STEAM

A

T O W E R

LP

VAC

B

T

O W E R

E X T R C

T O R

DEAERATED

FEEDSTOCK

FURFURAL

TREATI NG SECTI ON

STEAM

RAFFI NATE RECOVERY

SECTI ON

SOLVENT PURI FI CATI ON

Flash Tow er

MP

HP

S T R

I P P E R

EXTRACT E RECOVERY SECTI ON

R/ D RAFFI NATE

R/ D EXTRACT

VAC

FURFURAL

SOLVENT DE WAXING UNIT

7/31/2019 S_Bose

28/44

Objective

To remove paraffinichydrocarbons so thatLOBS is suitable for lowtemp. ap plic ation

The Proc essExtrac tion a ndc rystalliza tion to a c hievede-waxing, followed byFiltration & SolventRecovery

Solvent : MEK & Toluene ineq ual p rop ortions.

Toluene is oil solvent &MEK is anti wax solvent.Feed c harac terized by

Density, Kin. Visc & RI

LOBS c ha rac terized by KV,P.Pt., VI, Fl.Point,

SOLVENT DE-WAXING UNIT

General Effec ts of Refining on Main

7/31/2019 S_Bose

29/44

gCharac teristic s of Lube Oil Frac tions

General Range of Changes Brought aboutMainCharacteristics Solvent

Refining

Dew axing Hydro

finishing

Viscosity --

V.I. - -Pour Point

C.C.R --

Acidity --

Sulphur --

Colour --

CATALYTIC DE-WAXING UNIT

7/31/2019 S_Bose

30/44

CATALYTIC DE WAXING UNIT

PURGEHYDROTREATING MSDW

HYDROFINISHING

RECYCLE

FEED

MAKE UPHYDROGEN

PRODUCTFRACTIONATION

SECTION

NAPHTHA

DIESEL

GROUP II / GROUP III LOBS PRODUCT

SEPARATOR

HDT. EFFLUENTSTRIPPING & SCRUBBING

SIMPLIFIED PROCESS SCHEME

Fl id i d C l i C ki U i (FCCU)

7/31/2019 S_Bose

31/44

Fluid ized Ca talytic Crac king Unit (FCCU)

Objec tive : To c onvert Heavy Vac uum Gas Oil

to va luable d istilla tes like LPG, Gasoline, Dieselby c a ta lytic c rac king in fluid ized bed .

Feed : VGO/ RCO/ VR/ HydroCrac ker Bottom.

Catalyst : Silic a & Alum ina Zeolite Struc ture

7/31/2019 S_Bose

32/44

FCCU Produc t Qualities & End Uses

7/31/2019 S_Bose

33/44

No Product Qualities End Use

1. Gas H2S rich Off. Gas Refinery Fuel Gas after

Amine scrubbing2. LPG H2S, Mercaptons,

olefins like

Propylene/Butylene

To LPG Pool/Petrochemical feedstock

3. Gasoline High Octane No. andhigh Olefin contents

MS Pool

4. HNaphtha+ LCO

Low Cetane no. HighS, Unsaturates

Diesel Pool afterHydrotreatment

5. CLO High Aromatics, GoodCutter Stock

Fuel Oil

FCCU Produc t Qualities & End Uses

Yield pattern of Different Types of FCC

7/31/2019 S_Bose

34/44

VGO FCC RFCC INDMAX PETROFCC

FEED VGO VGO+VR VGO+VR VGO

FEED QUALITY CCR, WT% 0.74 4.06

7/31/2019 S_Bose

35/44

Hydro cracking Unit

Objec tive : To c onvert Heavy Vac uum

Gas Oil to valuable d istillates like LPG, Naphtha , ATF,Kerosene and Diesel.

Feed : VGO / Coker Produc ts

Opera ting Conditions

- Tem pera ture range : 370 420 o C

- System Pressure : 160 170 kg/ c m2(g)

Cata lyst : - Ni/ Mo oxides for hydro-trea ting- Ni/ Mo/ W(Tungsten) for Hyd ro-c rac king

Hydro Cracker Unit Flow Scheme

7/31/2019 S_Bose

36/44

Hydro Cracker Unit Flow Scheme

Wash WaterF-1

F-2

MUC

E-1

R-1 R-2

To MUGPRT

CRV-2 V-3

V-8 V-9

MPU

Gas & LN to LightEnd

Recovery SectionHP Amine

RGC

AmineScrubber

Diesel

HeavyNaphtha

UnconvertedOil

ATF/Kero

HydrocrackingReactor

HVGO

Feed Preheat Ex

G-1

Makeup H2

FeedFilter

V-1

PSA

Ex

MPU

HCU Produc t Qua lities & End Uses

7/31/2019 S_Bose

37/44

HCU Produc t Qua lities & End Uses

No. Product Qualities End Uses1. Gas H 2S rich Off. Gas Refinery Fuel Gas

after Amine Wash

2. LPG H2S Contents LPG Pool after causticwash

3. Naphtha low Octane No. and lowS contents

Hydrogen Unit Feed /CRU feed/ Naphtha

4. ATF /

Kero

Low S and Low

Aromatics

ATF/ Kero.

5. Diesel Low S and High Cetane Euro IV/ III Diesel

6. UnconvertedOil Low S, High Saturates FCCU Feed

Delayed Coking Proc ess

7/31/2019 S_Bose

38/44

Feedstoc k : Vac uum Residue

Good proc ess for inc reasing d istilla tes and minimizingblac k oil prod uc tion.

Produc ts Yields :Ga s+loss 8%LPG 4%Na p htha 6%Ga s oil 43%FO 11%RPC 28%

Gas oil & Naphtha need further trea tment .

Delayed Coking Unit (DCU) flow scheme

7/31/2019 S_Bose

39/44

S

OAKER

NaphthaFR

ACTIONAT

ORFEED

Delayed Coking Unit (DCU) f low scheme

COK

E

CHAMBE

R

T=505 0C

Fuel Oil

Kero

Gas Oil

FurnaceFurnace

Gas/LPG

COK

E

CHAMBE

R

RFO

Pre heat Exchanger

SEP

A R

A TOR

Delayed Coker

7/31/2019 S_Bose

40/44

No Product Qualit ies End Uses

1. Gas H2S rich Off Gas Refinery FG afterAmine Wash

2. LPG Mercaptons, unsaturates LPG after Merox /Caustic wash

3. Naphtha Low Octane, High Olefins NHDT / DHDT feed4. Kerosene High unsatuartes DHDT Feed

5. Gas Oil Low Cetane No. and high

unsaturates

DHDT / HCU feed

6. Fuel Oil Good cutter stock Fuel Oil

7. Coke Low ash, Sulphur contentdepends on feed S

Gasification/ cementind. /ElectrodePreparation

Produc ts Qualities & End Uses

Sulphur Recovery - schemat ic

7/31/2019 S_Bose

41/44

Sulphur Recovery schemat ic

Flow sc heme of a modern refinery

7/31/2019 S_Bose

42/44

7/31/2019 S_Bose

43/44

Thank you

Thank you

BASIC REFINERY OPERATIONS

7/31/2019 S_Bose

44/44

Hydrocarbon molecules in crude do NOT meet customer needs

SEPARATION PROCESSES(Primary Processes)

CONVERSION PROCESSES(Secondary Processes)

FINISHING PROCESSES(Secondary Processes)

Segregate the molecules

Rearrange the molecules

Remove Contaminants

MARKETABLE PRODUCTS

Documents

S_Bose