The document provides details about various refinery units including: - Crude Distillation Unit (CDU), Naphtha Hydrotreating Unit (NHT), Isomerization Unit, Continuous Catalytic Reformer (CCR) Unit, Diesel Hydrotreating (DHDT) Unit, Vacuum Gas Oil Hydrotreating (VGO HDT) Unit, Fluidized Catalytic Cracking (FCC) Unit, Hydrogen Generation Unit (HGU), Polypropylene Unit (PPU), Sour Water Stripping (SWS) Unit, and Amine Regeneration Unit. It describes the objectives, key inputs and outputs of each unit.

1. PRESENTATION ON REFINERYUNITS
DESCRIPTION
Presented By:-
ARNAB CHAKRABORTY

2. Refinery Configuration

3. Refinery Units
• CDU / VDU/ NSU(Naph. Stablizn Unit)
• NHT, CCR, Isomerization [MS Block]
• DHDT
• VGO-HDT
• FCC-PC, PRU & FCC
• LPG/FG/Naphtha Treaters
• Delayed Coker Unit
• Polypropylene Unit
• Sulphur Block
• HRU
• HGU
• ATF Merox

4. CDU / VDU Plant Details
Unit Objective:
To separate crude oil into different products
by boiling point differences & Prepare feed
for secondary processing units.

6. Naphtha Hydrotreating Unit Details
Product:
Light Naphtha to Isomerization Unit Feed
Heavy Naphtha to CCR Unit Feed

7. NHT CONTD…..
• Heavy Naptha cut from the atmospheric crude oil distillation column in a refinery is
sent to a ‘Naphtha Hydrotreater Unit’. After the hydrotreater unit, naphtha is sent to
an isomerisation unit or a catalytic reformer unit, which often use reforming
catalysts. Most reforming catalysts contain platinum as the active material. Sulphur
and nitrogen compounds present in naphtha cut from atmospheric distillation
column can deactivate the catalyst and must be removed prior to catalytic
reforming.
• Purpose of the naphtha hydrotrater unit is to remove sulphur and nitrogen
compounds. The naphtha hydro treating unit uses a cobalt-molybdenum catalyst to
remove sulphur by converting it to hydrogen sulphide that is removed along with
unreacted hydrogen. Some of the hydrogen sulphide-hydrogen mixture is recycled
back to the reactor to utilize the unreacted hydrogen, using a compressor.
• Reactor conditions for naphtha hydrotreater unit are around 400-500˚F (205-260˚C)
and pressure of 350-650 psi (25-45 bar). As coke deposits on the catalyst,
reactor temperature must be raised. Once the reactor temperature reaches ~750˚F
(400˚C), the unit is scheduled for shutdown and catalyst replacement.

8. Isomerization Unit Details
• There are two distinct isomerization processes, butane (C4) and pentane/hexane
(C5/C6) Isomerization is a process in petroleum refining that converts n-butane, n-
pentane and n-hexane into their respective isoparaffins of substantially higher
octane number. The straight-chain paraffins are converted to their branched-chain
counterparts whose component atoms are the same but are arranged in a different
geometric structure. Isomerization is important for the conversion of n-butane into
isobutane, to provide additional feedstock for alkylation units, and the conversion
of normal pentanes and hexanes into higher branched isomers for gasoline
blending. Isomerization is similar to catalytic reforming in that the hydrocarbon
molecules are rearranged, but unlike catalytic reforming, isomerization just
converts normal paraffins to isoparaffins.
• Butane isomerization produces feedstock for alkylation. Aluminum chloride
catalyst plus hydrogen chloride are universally used for the low-temperature
processes. Platinum or another metal catalyst is used for the higher-temperature
processes. In a typical low-temperature process, the feed to the isomerization plant
is n-butane or mixed butanes mixed with hydrogen (to inhibit olefin formation) and
passed to the reactor at 230°-340° F and 200-300 psi. Hydrogen is flashed off in a
high-pressure separator and the hydrogen chloride removed in a stripper column.

9. CONTD....
The resultant butane mixture is sent to a fractionator (deisobutanizer) to separate n-
butane from the isobutane product.
• Pentane/hexane isomerization increases the octane number of the light gasoline
components n-pentane and n-hexane, which are found in abundance in straight-run
gasoline. In a typical C5/C6 isomerization process, dried and desulfurized feedstock
is mixed with a small amount of organic chloride and recycled hydrogen, and then
heated to reactor temperature. It is then passed over supported-metal catalyst in the
first reactor where benzene and olefins are hydrogenated. The feed next goes to the
isomerization reactor where the paraffins are catalytically isomerized to
isoparaffins. The reactor effluent is then cooled and subsequently separated in the
product separator into two streams: a liquid product (isomerate) and a recycle
hydrogen-gas stream. The isomerate is washed (caustic and water), acid stripped,
and stabilized before going to storage.
•

10. Simplified block diagram

11. CCR Unit Details
Unit Objective: The purpose of Continuous Catalytic Reformer Unit is to produce high
octane aromatics from paraffin and naphthenes for use as a high octane blending
component.
Reforming : Reforming involves conversion of low octane paraffinic & naphthenic
compounds to aromatics.
Feed Input:
• Hydrotreated Heavy Naphtha cut from Naphtha Hydrotreating unit
• Off gas from Isomerization Unit
Product Details:
• Reformate
• LPG
• Hydrogen

12. Simplified block diagram

13. DHDT Plant Details
Process Description:-
• In Diesel hydrodesulphurization/hydrotreating process, diesel feed is mixed with
recycle Hydrogen over a catalyst bed in a trickle bed reactor at temperature of 290-
400°C and pressure of 35-125 bar.
• The main chemical reactions in DHDS/DHDT are hydrodesulphurization(HDS),
hydrodenitrification (HDN), and aromatic and olefin saturation. These reactions are
carried on bi-functional catalysts.
• Reactor effluent is separated into gas and liquid in a separator. Gas is recycled back
to the reactor after amine wash along with make-up Hydrogen and liquid is sent to
the stripper for removal of light gases and H2S.
Unit Objective:
The process objective is to maximize production of diesel to meet the Euro IV
specifications.
Feed Input:
Mixture of LGO, HGO, Vacuum Diesel, LKO & HKO, Heavy Naphtha from
CDU/VDU, Coker Naphtha, LCGO from DCU, LCO from FCC Unit and DSO rich
stream from the LPG treating Unit

14. Simplified flow diagram of DHDT

15. VGO HDT Plant Details
Unit Objective:
The main objective of the unit is to produce hydro treated vacuum gas oil having
desired level of hydrogen, low sulphur and low nitrogen for the various design feed
cases. The hydro treated VGO is feedstock for the FCC (Petrochemical) unit.
Feed Input:
The feed stock of this unit is a mixture of Straight Run VGO from CDU/VDU and
HCGO from DCU unit.

16. VGO-HDT process flow diagram

17. FCCU Plant Details
Unit Objective:
The Fluidized Catalytic Cracking unit Petrochemical Complex is a Deep catalytic
cracking unit. The main objective of the unit is to produce feeds to various units
like PPU, M S Block & Offsite.
Feed Input:
Mix of straight run VGO and HCGO from CDU/VDU and DCU .
FCCU Product Details:
• Propylene to PPU
• Fuel Gas to FG Treating Unit
• LPG to LPG Treating Unit
• LCN / MCN Naphtha to MS Block
• LCN/MCN to MS Blending in Offsite

18. Simplified block diagram

19. HGU Plant Details
Unit Objective: To Generate Hydrogen of High Purity Required for Hydro-
processing Units of Refinery (NHT, DHDT, VGOHDT), ISOMER, PP & SRU
TGT.
Feed Input: SR Naphtha from NSU & DHDT Naphtha from DHDT
Product: Hydrogen for DHDT, VGO HDT, PPU, SRU, NHT, HRU

20. PPU Plant Details
Unit Objective: objective of Polypropylene (PPU) unit is to produce Polypropylene
from Propylene,
Polypropylene: Polypropylene is a long chain polymer made from propylene
monomers. After exposing the propylene to both heat and pressure with an active
catalyst, the propylene monomers combine to form a long chain polymer.
Polypropylene is a thermoplastic polymer.
Feed Input: Propylene from Propylene Recovery Unit of FCCU & Propylene
Mounded bullets
Product: Polypropylene Polymer
Uses of Polypropylene: Fibers, Automobiles plastic, Wires and cables etc

21. SWS Unit Details
Unit Objective: The process objective of SWS Unit is to process Sour water streams
generated in refinery process units CDU/VDU, DCU, Flare KOD, ARU, SRU-
TGTU, HGU and DCCU for Single Stage Stripper. Sour Water streams from
VGOHDT and NHTU for Two stage stripper for removal of H2S and NH3.
Feed Input:
Sour Water Stripper – I (SWS-I) : Sour water from CDU/VDU, DCU, Flare KOD,
ARU, TGTU, FFCU
Sour Water Stripper –II (SWS-II) : Sour water from VGO HDT, DHDT, NHTU
Product:
Stripped water to effluent treatment plant or water to CDU/VDU, FCCU, DCU.
Stripped water to effluent treatment plant or water to VGO DHT, DHDT, NHTU

22. Amine Regeneration Unit Details
Gases containing H2S or both H2S and CO2 are commonly referred to as sour gases
or acid gases in the hydrocarbon processing industries.
A typical amine gas treating process (as shown in the flow diagram (below)
includes an absorber unit and a regenerator unit as well as accessory equipment.
In the absorber, the downflowing amine solution absorbs H2S and CO2 from the
upflowing sour gas to produce a sweetened gas stream (i.e., a gas free of hydrogen
sulfide and carbon dioxide) as a product and an amine solution rich in the absorbed
acid gases. The resultant "rich" amine is then routed into the regenerator (a stripper
with a reboiler) to produce regenerated or "lean" amine that is recycled for reuse in
the absorber. The stripped overhead gas from the regenerator is concentrated H2S
and CO2. In oil refineries, that stripped gas is mostly H2S, much of which often
comes from a sulfur-removing process called hydrodesulfurization. This H2S-rich
stripped gas stream is then usually routed into a Claus process to convert it into
elemental sulfur.

23. CONTD....

24. Other plants or units at a glance
Sulphur regeneration unit:-
This unit produces sulphur from the H2S stream and later on the product of this unit
is sold off.
RWTP plant:- : Raw Water Treatment Plant (RWTP) produce filtered and treated
water to meet the requirements of: Cooling water make-up, DM plant feed,
Drinking water, Service water.
Effluent Treatment Plant :-ETP treats effluent water received from various units in
refinery and produce treated water for reuse in Refinery.
RO DM plant :-RO DM is a centralized facility for producing DM water for the
Refinery complex. DM water is required for following purposes: Boiler feed water
makeup for generation of steam, Process water for dilution of chemicals, washing
etc.

25. Flare System Details
Flare system Objective:
The flare system is provided for safe disposal of combustible, toxic gases which, are
relieved from process plants and off sites during start - up, shutdown, normal
operation or in case of an emergency such as:
• Cooling water failure
• General Power failure
• External fire case
• Any other operational failure
• Blocked outlet
• Reflux failure
• Local power failure
• Tube rupture
The refinery complex has two flare systems, one for Hydrocarbon flare for
process units & off-sites handling hydrocarbon and the other for the sulphur
block handling sour flare.

26. THANK YOU