Cdu Basic Engineering Design Basis

BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 1 of 13

Basic Engineering Design Basis Part A for Debottlenecking of Crude / Vacuum Distillation units and Naphtha Stabiliser Unit

at BORL- Bina Refinery

(Unit No. 11/12/13)

CLIENT

:

___________________________________________

EIL

:

_________________________________________

1

16.10.2015

ISSUED FOR PACKAGE

GN

SA

SA

0

29.04.2015

CLIENT COMMENT INCORPORATED AND ISSUED FOR APPROVAL

GN

SA

SA

Purpose

Prepared by

Reviewed by

Approved by

Rev. No.

Date

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BASIC ENGINEERING DESIGN BASIS PART- A

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 2 of 12

For Debottlenecking of CDU/VDU/NSU at BORL, Bina

TABLE OF CONTENTS Section #

Contents

Page #

1.0

INTRODUCTION

03

2.0

UNIT CAPACITY

03

3.0

PLANT TURNDOWN CAPACITY

04

4.0

MAJOR CONSTRAINT OF PRESENT DESIGN

04

5.0

FEEDSTOCK SPECIFICATIONS

04

6.0

FEED / PRODUCT SPECIFICATIONS

05

7.0

FEED AND PRODUCT BATTERY LIMIT CONDITIONS

07

8.0

CATALYST AND CHEMICALS

10

9.0

STORAGE INSIDE BATTERY LIMITS

10

10.0

PRIMARY EFFLUENT TREATMENT WITHIN BATTERY LIMITS

10

11.0

SCOPE OF BATTERY LIMIT FACILITIES

10

12.0

SPECIFIC DESIGN CONSIDERATIONS & KEY ISSUES

10

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BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina

1.0

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 3 of 12

INTRODUCTION The CDU unit of BORL Refinery was implemented as part of the New Refinery Project and commissioned in June-2010. Unit has been designed for 65: 35 weight blend of Arabian Light and Arabian Heavy for a crude processing capacity of 6.0MMTPA. BORL intends to augment the processing capacity of CDU from present 6 MMTPA to 7.8 MMTPA by Debottlenecking of the existing unit. BORL has entrusted Engineers India Limited (EIL) with the job of preparation of BEDP for debottlenecking of CDU/VDU & Naphtha Stabilizer. Basic Engineering Design Basis (BEDB) for all facilities, containing technical information agreed between Client and EIL shall be binding on the process design and engineering of units, utility systems and offsite facilities. The BEDBs for each facility are in two parts: Part A: Unit Design Basis providing necessary data for specific process unit / utility systems and offsite facilities. Part B: Basic Engineering Design Basis. This document constitutes Part A of the Basic Engineering Design Basis for preparation of the Basic Engineering Design Package for the debottlenecking of CDU/VDU & naphtha stabilizer unit.

2.0

UNIT CAPACITY Crude Distillation Unit : 7.8 MMTPA of crude feed. Vacuum Unit : Of Matching capacity. Naphtha Stabilizer Unit : Of Matching capacity.

2.1

ONSTREAM FACTOR Stream factor

3.0

:

8280 hrs / year

PLANT TURNDOWN CAPABILITY Turndown desired is 50% of design capacity. However, actual achievable turndown shall be governed by column / heater turndown limitations and shall be indicated later.

4.0

MAJOR CONSTRAINT OF PRESENT DESIGN Following are the major constraints experienced during test run with 100% AM crude:

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BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina



Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 4 of 12

 

Vacuum column overhead condensing capacity is limiting due to lower flow of Cooling Water. Preheat train crude outlet temperature lower by 25 Deg C than design. Desalter outlet salt and BS&W are higher than design (salt 1.2 ~ 1.5 ptb against design of 1.0 ptb and BSW 0.2 vol% againt design of 0.05 vol%)



CDU overhead condensing capacity is limiting with column operating upto 2.7 kg/cm2g



Corrosion/fouling issues in the following sections; o CDU APH and ID fan corrosion (due to high H2S in hot well off gases up to 10.0 vol%) o Fouling of the Kero reboiler resulting in the duty loss o CDU overhead condenser tube side depositions resulting in tube leaks and limiting service life to about one year



Product qualities; o VGO asphaltenes and CCR up to 200 ppmw and 0.6 wt% respectively against the specification of 150 ppmw and 0.5 wt% o Different hot and cold SRGO densities o Lighters in VR (D1160 IBP and 5% in the range of 470 and 525 deg C respectively) and sodium content in the range of 20~25 ppmw against the desired value of 15 ppmw



Vacuum column slop recycle pump not able to discharge slop to vacuum heater inlet due to head limitation Crude heater ID fan is limiting resulting in partial opening of main stack damper at 110% throughput.



5.0

FEEDSTOCK SPECIFICATIONS

5.1

DESIGN CASE Debottlenecking of CDU/VDU & Naphtha Stabilizer shall be carried out for following design case:  100% processing of Kuwait. In addition, the following check cases to be studied:

5.2

CHECK CASES 1. 100% Processing of 65: 35 weight blend of Arabian Light and Arabian Heavy. 2. 100 % Basra Light.

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BASIC ENGINEERING DESIGN BASIS PART- A

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 5 of 12

For Debottlenecking of CDU/VDU/NSU at BORL, Bina

For check cases PFDs, Stream Summary and heat & material balance indicating operating conditions at key locations and Major Equipment limitation for each of the cases would be provided. Selected Crude Property: CRUDES

KUWAIT (Design Case) 30.4 7.3 9.4 -58.2

API VISCOSITY@50 °C, cSt VISCOSITY@40 °C, CSt POUR POINT, °C 5.3

Arab Mix (Check Case) 31.3 7.7 10.3 -44.3

Basrah Light (Check Case) 30.0 7.6 9.9 -20.1

ASSAY DATA The following Assay Data are adopted for design/check cases

5.4

(a)

Kuwait (KUWAIT304)

-

Refer Attachment-I

(b)

Arab Mix (AL: AH -65:35) (ARBLT332 +ARAHV277)

-

Refer Attachment-II

(c)

Basra Light (BASRL300)

-

Refer Attachment-III

LIGHT ENDS QUANTITY Wt%

Existing Design AM

KUWAIT

Kuwait (From Assay)

Kuwait (Designed)

C1

0.000

0.000

0.000

0.0062

C2

0.011

0.028

0.004

0.022

C3

0.2702

0.3983

0.175

0.317

iC4

0.1702

0.2359

0.155

0.2808

nC4

0.943

0.8977

0.749

1.3524

iC5

0.5827

0.1319

0.720

0.3969

nC5

1.2498

0.0405

1.260

0.6911

TOTAL

3.227

1.732

3.064

3.064

Note: Based on operating experience, LPG product from NSU varies from 0.9 wt% to 1.9 wt% of crude feed, depending upon type of crude blend being processed in the unit (1.9 wt% LPG for Kuwait case). LPG yield, the FG, LPG and Naphtha section shall be checked for 140 % revamp. However in case if it calls for hardware change which cannot be implemented in 40 day shutdown period, the same will be restricted to maximum achievable capacity.

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BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina

6.0 6.1

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 6 of 12

FEED / PRODUCT SPECIFICATIONS Performance and Product Characteristics for Desalter.

6.1.1 Feed Characteristics (Min) To Be Considered For Design: Desalter crude feed: The bulk crude feed characteristics e.g. API, Viscosity and pour point shall be as per crude assay. Following characteristics, which depend upon crude transportation/ receipt and storage, shall be adopted for desalter design KUWAIT RVP, kg/cm2a Flowing vapour pressure kg/cm2 a Salt content, Lb/1000 barrel (ptb) Bottom sludge (BS&W), % vol

&

water

0.25 6.6 30 1 2.0 (including sediment=0.4%max)

6.1.2 Desalter: The existing unit has single stage desalter. To meet the required desalted crude salt and BS&W content, an additional first stage desalter parallel to existing one and second stage desalter series to both the new and existing first stage desalter with associated facilities shall be considered. Desalted crude characteristics shall be as follows: Outlet salt content BS&W

: 0.5 ptb max, based on inlet salt content of 8 – 30 ptb. : 0.2 vol% (guarantee)

Oil content in brine

: 250 ppmv (Guarantee)

However, desalter vendor is to confirm these values. 6.2

PERFORMANCE AND PRODUCT CHARACTERISTICS FOR CRUDE DISTILLATION / NAPHTHA STABILIZER UNIT Key Specifications for Products: The units shall be designed to meet all product specifications that can be controlled by distillation and indicated below. Other specifications such as sulphur, octane number, cetane number etc, which are not controlled in the units need to achieved in downstream units.

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BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 7 of 12

ASTM D 86/1160 distillation shall be reported for all column draw offs streams including combined gas oil, RCO and VGO. Products from Crude, Vacuum Distillation & Stabilizer Units LPG  Vapour Pressure at 40oC, kg/cm2g 10.4 max o  Evaporation temperature for 95 vol%, C 2.0 max  C2 & lighter content, wt% 0.2 max Stabilized Naphtha  Cut point IBP-150 C as feed to NHT unit  C4 content : 0.5 wt% max.  RVP : 0.4 kg/cm2a max Kerosene  Expected cut point 150 – 220 C on crude TBP.  This stream is routed to ATF treating unit for production of ATF.  Flash point : 40 C (minimum)  Kero sulphur : 0.235 wt% max  LGO section shall be suitable for dropping Kero to achieve; o Kero sulphur as 0.235 wt% max o Kero cut point 150- 220 C on crude TBP Gas Oils  This consists of Light gas oils (LGO), Heavy gas oils (HGO) from crude column and vacuum diesel from Vacuum column.  Expected cut point 220- 370 C on crude TBP.  This stream is routed to DHT unit.  Flash point : 66 C (minimum)  ASTM D86 95% point not exceeds 368 C. Hot well gasses  Will be included in stream summary and reported as obtained. No specifications. Hot well slop oil  Report as obtained. No specifications Vacuum Diesel  This stream shall be blended to other diesel streams from Crude column with in CDU/VDU battery limit. Light Vacuum Gas oils (LVGO)  Expected cut point 370-450 C on crude TBP.  Shall be blended with HVGO inside CDU/VDU battery limit to get a Vacuum Gas oil (VGO) stream.

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BASIC ENGINEERING DESIGN BASIS PART- A

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 8 of 12

For Debottlenecking of CDU/VDU/NSU at BORL, Bina

Heavy Vacuum Gas oils (HVGO)  Expected cut point 450-565 C on crude TBP.  Shall be blended with LVGO inside CDU/VDU battery limit to get a Vacuum Gas oil (VGO) stream. VGO, which is to be routed to downstream Hydrocracker unit shall meet the following key specifications. S.No . 1 2 3 4

Properties

Specifications

Total metals, (Ni+V) ppmw Asphaltenes, C7 insolubles, ppmw Chevrom Test Method (CTM) Sodium, wppm max CCR wt%

2 max. 150 max. 1.0 0.5 max

Vacuum slop  Slop draw provision shall be retained and provision for slop recycled to vacuum furnace as well as to VR circuit shall be kept. Slop is not a product. Vacuum Residue As feed to Delayed Coker Unit for further processing with max sodium limits as 15 ppmw. The Sodium level in VR shall be controlled by desalter and caustic dosing system. 7.0 FEED AND PRODUCT BATTERY LIMIT CONDITIONS Battery Limit Conditions: The battery limit temperature and pressure conditions for the incoming and outgoing process streams as per existing unit are indicted below.

Incoming/Outgoing Streams

Crude

Operating Mechanical design Conditions Pres. Temp oC Pressure Temp oC Kg/cm2 g Kg/cm2g INCOMING LINES 1

Source/Destination

8.0

30

13

65

Crude Storage Tank

Stripped sour water

3.0

70

17

120

SWS

Flushing oil

6.0

Amb

16.5

65

Offsite

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BASIC ENGINEERING DESIGN BASIS PART- A

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 9 of 12

For Debottlenecking of CDU/VDU/NSU at BORL, Bina

Incoming/Outgoing Streams

Caustic 20 wt%

Operating Conditions Pres. Temp oC 2 Kg/cm g 6.0 40

Hot Oil

11

Mechanical design

260

Source/Destination

Pressure Kg/cm2g 18

Temp oC 65

Offsites

14.8

275

MS block

OUTGOING LINES LPG

19.5

40

31.9

65

LPG Treating Unit

Stabilised Naphtha 1

3.0

40

14.5

65

NHT feed tank

6.0

108

14.5

218

NHT unit feed

5.0

40

16.5

65

5.0

40

16.5

65

Product Storage (out side Bina Refinery) ATF treating Unit

5.0

40

16.5

65

Diesel blending

3.0

40

16.5

65

Fuel oil blending

6.0

40

24

65

DHDT Feed Tank

11.0

160

24

190

DHDT unit hot feed

3.0

40

24

65

FLO Tank

12.0

80

29.3

100

HCU Feed Tank

13.0

170

29.3

190

HCU unit hot feed

9.5*

170

31

180

VR Storage

8.0

186

31

220

DCU hot feed

4.5

45

65

Sour water stripper

White slops

7.0

40

24

65

White Slop tank

Black slops

4.0

80~160

31

180

Black Slop tank

Brine

3.0

45

31.4

65

ETP

Kerosene

1 Gas Oil (LGO+HGO), Slop oil (from Hot well) and Vacuum diesel 1 VGO (HVGO +LVGO) Vacuum Residue

Sour water

1

1

1 13.0

*@75% Flow The above are the minimum pressure values at the battery limit of CDU/VDU. Designer to update these values consistent with the downstream units and tankage requirements during the progress of the offsite design. 8.0 CATALYST AND CHEMICALS Suitable provision for chemical dosing along with CI probes shall be kept in the unit for higher TAN and Calcium crude processing. Maximum TAN will be limited to 1.0 with existing conventional metallurgy along with chemical dosing.

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BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina

9.0

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 10 of 12

STORAGE INSIDE BATTERY LIMITS No additional facility required.

10.0 PRIMARY EFFLUENT TREATMENT WITHIN BATTERY LIMITS None. 11.0 SCOPE OF BATTERY LIMIT FACILITIES Facilities within battery limits to be finalised during design shall be consistent with offsite to facilitate smooth transfer of feed, products, utilities and chemicals. 12.0 SPECIFIC DESIGN CONSIDERATIONS & KEY ISSUES 12.1.0 ATMOSPHERIC/VACUUM DISTILLATION UNIT 1) Following over-design philosophy shall be considered. 

For checking adequacy of the existing equipment, no de-rating factor shall be considered assuming that all existing equipments are available as per original design. No over-design margin to be considered for existing equipment adequacy check.



In case of new/replaced equipment, over-design margin to be considered as per EIL’s standard practices.

2) Constraints in any of the section shall be studied & suitably mitigated for design case. 3) Hotwell off gases after suitable H2S removal facilities shall be routed to CDU heaters or safely vented to atmosphere. Hotwell off gases Treatment facility should be designed for 100% Kuwait crude oil processing case. The following is the flow and composition of Hot well off gases: HOT WELL GAS

Design Case 1

H2S H2 N2 CO CO2 O2 C1

MOL% 10.17 4.28 30.67

Format No. 3-0241-1071 Rev. 1

Design Case 2 WT% 13.57 0.26 0.86 0.26 16.79

MOL% 13.02 4.3 1.00 0.26 34.25

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Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 11 of 12

For Debottlenecking of CDU/VDU/NSU at BORL, Bina

C2 C3 C3= Total C3 i-C4 n-C4 iC4= 1C4= Cis C4= Trans C4= Total C4 i-C5 n-C5 C5+ C6 Total C5 + C6 TOTAL FLOW (KG/HR)

17.46 14.47 1.44 15.91 8.61 3.99 2.71 0.672 0.2 1.77 17.95 1.41 2.1 0.08 3.59 100

11.02

11.99

23.09

17.13

22.82

12.84

11.33

5.2

100 2580

100

Design case 1: Actual Plant operating Data. Design case 2: Theoretically Calculated Data. 4) The existing overhead ejector system originally designed as 3 stage ejector system is to be implemented for debottlenecking as Hybrid system with last stage as LRVP (to be reviewed) 5) EIL shall ensure that all revamp modifications shall be implementable in 40 engineering days during turnaround.

6) Each section of crude and vacuum column shall be revamped to the maximum possible achievable capacity with hardware modifications that can be implemented in 40 days shut down period. Section wise hydraulic study report with max loading in each section shall be provided.

7) As per “OWNERS REQUIREMENT” Preflash drum will be considered in design. However CDU heater will be revamped to the max possible achievable capacity with modifications which can be implemented in 40 days shut down time. 8) Adequacy of existing vacuum column feed inlet flash device shall be checked if found not adequate then latest generation and proven Vacuum column feed inlet device shall be considered.

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BASIC ENGINEERING DESIGN BASIS PART- A For Debottlenecking of CDU/VDU/NSU at BORL, Bina

Document No. A702-011-02-41-PDB-001 Rev. No. 1 Page 12 of 12

9) Provision for routing CDU overhead excess gases (from accumulator) to heater after amine treatment shall be considered. 10) CDU Column overhead condenser shall be modified by addition of a new third shell (11-EE00-101C) in parallel to existing two shells (11-EE-00-101A/B) To improve the reliability of crude overhead condensers, following requirements shall be considered; o Crude preheat temperature (inlet temperature for first stage condensers EE101) shall be increased to avoid the shock condensation which is currently being experienced o Based upon the current experience of frequent failure of overhead condensers, a third condenser shall be considered for redundancy. 11) TI shall be provided in crude outlet of each exchanger in preheat trains 12) New Cooling Water Booster Pump for VDU overhead ejector condenser to improve VDU column vacuum 13) Strainer in the cooling water for VDU overhead ejector condenser to arrest fills from cooling tower 14) High TAN crude processing study shall be included. Provision for Corrosion/Fouling protection for processing high TAN crudes shall be considered i. High temp corrosion inhibitor dosing points ii. Corrosion probes at strategic locations iii. Provision of Antifoulant dosing in crude iv. Wash water injection in crude preheat train shall be considered 15) Margin shall be kept for slop processing of 20 Mt/hr

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