TAKREER Ruwais Refinery Expansion

1620 Ethylene Recovery Unit

Capacity : 1,490 T/d of ROG feedstock from USGP

Main Feed : Refinery off-gas from the Fuel Gas Absorber in the Unsaturated

Gas Plant and Deethanizer vent from PRU. Objective : To recover polymer-grade ethylene product after removing

contaminants and separating out fuel gas and C3+ streams.

Separation of Refinery Off Gas (ROG) into high

value products Polymer Grade Ethylene C3+ Stream(recycled to PRU For propylene

recovery) By-product Fuel Gas

ERU - OVERVEIW

Contaminants are removed by adsorption in: Dryers RSH/COS Removal Beds – Dryers and the RSH/COS Removal Beds are regenerated on a short cycle – DeOxo Reactor is regenerated infrequently Arsine removal Beds Mercury removal beds Product specs are met by the Acetylene polishing

Process requires removal of contaminants

Main Components of ERU

Contaminant Removal Components

1. DeOxo Reactors

2. Caustic Tower

3. Dryer Beds

4. RSH/COS Removal Beds

5. Arsine Removal Bed

6. Mercury Removal Bed

7. Acetylene Polisher

Main Separation Components of ERU

1. Deethanizer

2. HRS Modules

3. Demethanizer

4. C2 Splitter

5. C2 Refrigeration

6. C3 RefrigerationSera3 Ref

DeOxo Reactors

Removes O2, NOx, and some acetylenes including butadiene from ROG feedstock

DMDS is injected to moderate the reactor catalyst temperature and reduce undesirable hydrogenation reaction

DeOxo Steam heater – preheats feed stream to 190oC using superheated HP steam

Catalyst requires regeneration after 18 months

ROG outlet stream is cooled to 55 deg oC before entering the Caustic Tower.

Caustic Tower

Removes acid gases H2S and CO2 and ammonia by reaction with caustic

PRU vent gas, containing some CO2, will be added to the feed before it enters the Caustic Tower

ROG passing overhead is cooled by propylene refrigerant and the condensed water is separated out before it is reheated and routed to the dryers

Dryer Beds

Two Dryer Beds provide uninterrupted dehydration of treated ROG

While one bed is in service, the other is regenerating or on standby

The switching and regenerating sequences are automatic

Each vessel operates on a minimum 36-hour drying cycle

RSH / COS Removal Beds

Remove ammonia, mercaptans, COS, H2S, and CO2

A parallel vessel is provided for regeneration while the other is in service

They are regenerated on a 72-hour cycle

Arsine & Murcury Removal Bed

ARSINE REMOVAL BED :

Removes arsine and trace sulphur compounds by a chemical reaction

Fixed, non-regenerable type bed consisting of R9-12 lead Oxides

MERCURY REMOVAL BED :

Removes mercury by adsorption

Fixed, non-regenerable type bed sulphur impregnated carbon

Deethanizer

Removes heavier components from ROG and routes them to PRU

Deethanizer overhead stream is essentially free of C3’s

Overhead stream is compressed in Deethanizer Heat Pump, cooled, flashed, and used as Deethanizer and Demethanizer reflux

Heat source to the Deethanizer Reboiler is C3 refrigerant, which is being chilled in the reboiler

Deethanizer bottoms flow to PRU

HRS Modules

Vapor from the Deethanizer Reflux Drum is partially

condensed with refrigerant and sends liquid to Demethanizer

Remaining vapor is split into two streams:1. Sent to bottom of HRS Rectifier2. Partially condensed with refrigerant and fed into HRS Rectifier

HRS Rectifier overhead stream is partially condensed with

the liquid used as reflux and the vapor routed into the Demethanizer overhead stream

HRS Rectifier bottoms flow to the Demethanizer

Demethanizer

Demethanizer overhead stream is partially condensed with refrigerant using a core-type exchanger in the top of

the column, with the liquid used as reflux and the vapor expanded and used to condense HRS Rectifier overheads

Demethanizer bottoms flow to the C2 Spliter

C2 Splitter

Separates ethylene from ethane

Overhead stream is partially condensed with liquid

C2 collecting the C2 Refrigerant Surge Drum for reflux / withdrawal and the vapor feeding the third stage of the C2 Refrigerant Compressor

Ethane from the bottom of the C2 Splitter is vaporized

by condensing part of the ethylene refrigerant and is used for chilling the Deethanizer overhead before being sent to Battery Limits as fuel gas

C2 Refrigeration

. A three-stage Ethylene Refrigerant Compressor supplies refrigerant to various users at the -61°C, -83°C and the -100°C levels, respectively

Ethylene from the final stage discharge is desuperheated against propylene refrigerant with part being condensed by reboiling the C2 Splitter and part by vaporizing the C2 Splitter bottoms

The balance is condensed using -40°C propylenerefrigerant

C3 Refrigeration

A three-stage Propylene Refrigerant Compressor supplies refrigerant to various users

at the 5°C, -19°C and the -40°C levels, respectively

Propylene is condensed against cooling water

Catalyst Preparation & Regeneration

Deoxo Reactor-1620-D-002A/BAre regenerated on an infrequent basis (once

every 1-2 years)Reactor is heated with N2 & then LP steam

superheated to 250 deg.C using Electric Heater 1620-B-001.

The Air is supplied from plant air system The carbon is burned off until there is no rise

in bed tempAfter regeneration the catalyst required

reduction with N2 and H2During reduction ,the gas is circulated using

blower 1620-K-001 after being cooled in Air cooler 1620-EA-002 and fed to KO drum1620-D-031.

Catalyst Preparation & Regeneration

Catalyst is fresh is requires both reduction and sulphiding.DMDS is injected into N2/H2

The DMDS is dissociated into H2S when heated.

The hot N2/H2 and H2S are fed to the reactor and gas is is circulated through the Air cooler 1620-EA-002,KO drum 1620-D-031 and Blower 1620-k-001

Sulphiding is done before off gas is charged to the Caustic Tower

Catalyst Preparation & Regeneration

ROG Dryer regenerationThe ROG Dryer are regenerated once every 36 hourDuring the heating step, ERU Rasidue gas from Gas compressor 1620-K-002 to the Dryer regeneration steam heater 1620-E-026The heating step heats the bed at a controlled rate with the max. Temp. of the gas at 232 deg.CThe cooling step uses cold Regen Gas bypassing Regen Gas Steam Heater via TV-257B

The hot regen gas is sent to the Fuel Gas Header

Catalyst Preparation & Regeneration

RSH/COS Removal BedsThe dry ROG gas flows to the RSH/COS removal beds 1620-D-005A/BEach vassel contain BASF Selexsorb Cos and Selexsorb CD adsorbent The RSH/COS Removal Beds are regenerated once every 72 hoursThe regeneration gas is sent from residue gas compressor 1620-K-003 and electric heater 1620-B-001 to heat the gas going to RHS/COS Bed

The peak temp. for regeneration will be 290 deg.C

Catalyst Preparation & Regeneration

Arsine removal BedsThe Arsine removal bed 1620-D-006 which is fixed non regenerable typeThe bed material consist pf R9-12 lead oxides

The Mercury removal bedsThe Mercury removal bed 1620-D-007 which is contain non regenerable fixed bad

The bed material consist of sulphur impregnated carbon

Complex control in ERU

Total 15 no. complex control in ERU1.Residue gas –compressor K-003 discharge temperature control P &ID 5578-E2-1620-PRP-D-132

2.Regeneration system back pressure control P &ID 5578-E2-1620-PRP-D-116

3.Regeration system differential Pressure Control P &ID 5578-E2-1620-PRP-D-116

4.ROG Dryer D-004A/B Sequence control P &ID 5578-E2-1620-PRP-D-109 & P &ID 5578-E2-1620-PRP-D-110

Complex control in ERU

5. RSH/COS Removal bed D-005A/B Sequence control P&ID 5578-E2-1620-PRP-D-111 & P&ID 5578-E2-1620-PRP-D-112

6.Deoxo Reactor Steam heater E-002 Control P&ID 5578-E2-1620-PRP-D-102

7.Fresh Caustic Dosing Control P&ID 5578-E2-1620-PRP-D-105 & P&ID 5578-E2-1620-PRP-D-107

8.Regeneration Gas Steam Heater E-026 Control P&ID 5578-E2-1620-PRP-D-114

Complex control in ERU

9.RSH/COS Regeneration Gas Electric Heater B-001 control

P&ID 5578-E2-1620-PRP-D-114

10.E-016 Chiller Overheads Bypass Control P&ID 5578-E2-1620-PRP-D-127

11.Residue Gas Expander EX-003 Capacity Control P&ID 5578-E2-1620-PRP-D-131

12.C2 Splitter Reflux Ration Control P&ID 5578-E2-1620-PRP-D-135

Complex control in ERU

13.Acetylene Polisher ROG temperature control P &ID 5578-E2-1620-PRP-D-11314.Treated ROG Bypass Control P &ID 5578-E2-1620-PRP-D-113B15.Caustic Tower wash water make-up cooler

temperature ControlP &ID 5578-E2-1620-PRP-D-205

REFERENCE DOCUMENTS

1. PFDs2. P&IDS3. CAUSE & EFFECT4. EQUIPMENT DATA SHEET5. O & M MANUAL6. PROCESS DESIGN BASIS7. COMPLEX CONTROL8. CATALYST & CHEMICAL SUMMERY9. PLOT PLAN10. PROCESS EQUIPMENT LIST

CLICK ON DOCUMENT NAME TO OPEN

Cause & Effect

FOR DETAIL SEE THE C& E ESD001-Deoxo reactor shutdown 1 ESD002-Deoxo reactor shutdown 2ESD003- ROG to Deoxo reactor 1620-D-002A/B Press. Low lowESD004-Deoxo reactor regeneration shut down for Reactor bed temp high high 2oo12ESD005-Deoxo reactor regeneration shutdownfor control valve Diff. pressureESD006-Deoxo reactor regeneration shutdown for heater Temp. high highESD007 –Regeneration Blower 1620-K-001 tripESD008-Deoxo reactor regeneration shutdown for KO drum level high high

Cause & Effect

ESD034-Deoxo reactor regeneration shutdown for regeneration Blower flow low lowESD035-Deoxo reactor regeneration shutdown for N2 flowLow lowESD012-Low temp protection for Fuel gas & borouge plant Feed lineESD013-High temp protection for regeneration gas lineESD014- Regen gas 1620-B-001 elect. Heater temp high highESD017- Residue gas expander/Comp. tripESD018-Low temp. protection for regeneration/fuel gas lineESD020-1620-K-004 Ethylene refrig comp trip

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Cause & Effect

ESD021-1620G-007A/B Ethylene product pump isolationESD022-1620-K-005 C3 refrigeration comp. tripESD023-Caustic tower low level trip 1620-C-001ESD024-Caustic dryer feed KO drum low level tripESD025-Deethaniser low level trip 1620-C-002ESD026-Deethaniser reflux drum low level tripESD027 –C2R Surge drum low level tripESD028 –Caustic tank high temp tripESD033- Demethaniser low level tripESD029-Acetelene polisher high temp tripESD030-Acetylene polisher shutdown

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Cause & Effect

ESD031- Acetylen polisher N2 purgeESD032- High temp protection for condensate lineESD201- Reactor/Caustic & Dryer system isolateESD202-C2R System isolate blow down & de pressureESD203-C2R Surge C2 splitter isolate ESD204-1620-EX-003/K003 isolate & de pressureESD207-C3 Refrigeration System isolate & blow downESD011-1620-K-002 Deethaniser heat pump tripESD212-Deethaniser isolation & depressurizationESD213-Demethaniser isolate & depressureESD214-LP flare drum condensate pump start/stopESD300/301- Unit shutdown/Depressurization

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