Lopa Report _Nsrp_Unit 020_Rev1.Pdf

LOPA REVALIDATION Study Report Project/MOC Name Consultant Walame N.G., Pragna Consultants, India Session Day 16 days, from 26/Mar/2024 to 12/Apr/2024 Study Location NSRP office, Nghi So

LOPA REVALIDATION Study Report

Project/MOC Name

Consultant Walame N.G., Pragna Consultants, India

Session Day 16 days, from 26/Mar/2024 to 12/Apr/2024

Study Location NSRP office, Nghi Son, Vietnam

No of Recommendations 42

Recording Software Sphera Phapro

Thanh Hoa, Date – Month – Year,

LOPA Leader Project director, Pragna

CONFIDENTIAL INFORMATION

COPYRIGHT RESERVED The information and design details in this document are the property of Pragna Consultants Pvt Ltd and/or its associates Except as provided below the document is issued on the strict condition that except with the written permission of Pragna Consultants Pvt Ltd

it must not be reproduced, copied or communicated to any third party, nor be used for any purpose other than that stated in the particular enquiry, order or contract with which it is issued The reservation of copyright in this document extends from each date appearing there-on and in respect of the subject matter as it appeared at that relevant date

REVISION HISTORY

incorporated

Contents

1 PURPOSE AND SCOPE 4

2 EXECUTIVE SUMMARY 4

3 PROCESS DESCRIPTION 5

4 LOPA WORKSHOP AND FINDINGS 6

4.1 LOPA Team members & Attendance 6

4.2 HAZOP Node List 6

4.3 LOPA Sessions 7

4.5 LOPA Worksheets 9

4.6 LOPA Recommendation 10

4.7 Existing Independent Protection Layers (IPLs) 10

4.8 CONCLUSION AND FUTURE STUDY 11

5 LOPA STUDY DETAILS 11

5.1 Assumptions 11

5.2 Tolerability and ALARP Criteria 11

5.3 LOPA Procedure 11

5.4 Independent Protection Layers (IPL 12

5.5 Safety Instrumented Functions (SIF) 12

5.6 Safety Integrity Level (SIL) 12

5.7 Reference standards/procedures 13

6 ATTACHMENTS 13

Attachment 6.1 Attendance sheet 13

Attachment 6.2 LOPA Recommendations 13

Attachment 6.3 LOPA Worksheets 13

Attachment 6.4 LOPA IPL List 13

Attachment 6.5 NSRP Risk Assessment Matrix 13

Attachment 6.6 NSRP ALARP – Risk Triangle 13

Attachment 6.7 NSRP Tolerability Criteria Excerpts 13

Attachment 6.8 List of SIF with SIL 13

Attachment 6.9 LOPA Flow Chart 13

Attachment 6.10 List of Identical node equipment 13

1 PURPOSE AND SCOPE

NSRP Refinery and Petrochemical Plant located in Nghi Son, Tinh Gia District, Thanh Hoa, Vietnam engaged the services of Pragna Consultants Pvt Ltd ( PC), India to conduct revalidation of the HAZOP Study followed by LOPA based SIL Classification study for their utility unit 20 along with other selected units This report was prepared by Pragna Consultants Pvt Ltd (PC), India based on the discussions held during the LOPA based SIL Classification Workshop for Unit 020 with the NSRP technical and operation teams

2 EXECUTIVE SUMMARY

This report was prepared for M/s NSRP by Pragna Consultants Pvt Ltd ( PC) This report documents the results of the LOPA SIL ( SIL ) classification study conducted at the 020 units at the Plant located at Nghi Son Vietnam

The tool adopted for the SIL classification is Layers of Protection Analysis ( LOPA ) LOPA

is a semi-quantitative tool for analyzing and assessing risks on a process plant The LOPA study depends and builds on the information developed during HAZOP study It assigns risk levels to the scenario, systematically calculates the residual risks and identifies requirement of additional safeguards/ protection layers Through this process, the need

to have any Safety Instrumented Functions (SIFs) and their performance requirements are identified SIL classification is the process of arriving at the SIL requirements of the facility

The objectives of the LOPA study are to:

o Further analyze, through a semi-quantitative tool, the risk Scenarios identified in the HAZOP stage that has Personnel safety, Environment, asset damage and community impacts with RAM 5, 4 and 3E risk levels

o Clearly document all causes for the scenario, all conditions affecting the consequences, existing Independent Protection Layers (IPLs) including Safety Instrumented Functions (SIFs)

o Assign failure rates, numerical values and probability of failure on demand to causes, conditions and protection layer

o Calculate the event frequency for the subject scenario and compare it with the Tolerable event frequency for the scenario to arrive at the LOPA GAP, which indicates if the existing risk is acceptable as per corporate risk guideline

o Provide recommendation if any additional risk reduction measures are required for the subject scenario

o All instrumented IPLs listed in Attachment 6.7 are included in the Preventative Maintenance program and are tested periodically

o The risk reduction factor for a BPCS (which does not conform to IEC 61511 or IEC 61508) used as a protection layer shall be equal to or below 10 ( PFD 0.1 )

o SIF spurious activation not used as an Initiating event

The LOPA report can be used to provide a traceable path from the identified risk scenarios to the performance requirements of each Independent Protection Layer or Safety Instrumented Function (SIF) It offers the user a structured, repeatable process to ensure that all identified risks are controlled, and the risk level is reduced to a tolerable level

The initial HAZOP as well as SIL Classification of the unit 020 was conducted by M/s JGCS

at EPC stage in 2014 SIL reliability calculations too was completed at the same time

A total of 26 recommendations were made during the LOPA/SIL workshop A complete list is provided in Attachment 6.2 NSRP organized a multi-disciplinary team knowledgeable in process engineering, operations and plant history to participate in the LOPA study The LOPA study was carried out according to NSRP procedure and International Standard IEC-61511

Ed 2.0 (2016) and IEC61508 Ed 2.0 ( 2010 ) And was conducted from 26th March to 12th April

2024 at Plant

The LOPA recommendations after approval by the management are to be assigned to individuals with target date for completion and to be monitored for implementation There is only one SIF recommended in this study at recommendation number 12 Subsequent steps, will include preparing a Safety Requirement Specification (SRS) for this identified SIF, design

of the SIF and conducting a SIL verification study to verify if the newly designed SIFs meet their intended performance requirements

3 PROCESS DESCRIPTION

The plant facility is for catalytic hydrogenation of the hydrocarbon feed from ATU using hydrogen at 18-19 MPa and temperature as per catalyst activity in the range pf 325-385 C in the two phase flow The product liquid is knocked off, the hydrogen gas is recycled back after the absorption of H2S produced in the hydrogenation at same pressure & the gas is recycled back with the make up fresh hydrogen gas using recycle gas compressor There are two modules of equal capacity & each of the modules have 2 trains Each train has 3 catalytic reactors in series Each reactor has two beds Each bed is provided with quench gas introduction arrangement

The separated liquid hydrocarbon is flashed at pressure of 2.8-3.5 MPa to flash out another gas amount from the liquid This flashed gas is treated to scrub the acid gases like H2S and sent to recompression to enable to recycle it for reaction The rich amine is flashed in flash vessel to separate the free sour gas & the rich amine liquid is sent to ARU The sour gas is sent LRU/RFCC

The hydrogenated liquid recovered as above is fed to fractionator to recover distillate (Unstabilised RHDS naphtha) which is sent to LRU

The middle cut is RHDS diesel which is sent to 153 TK-017/018 tanks

The bottoms is RHDS resids which is sent to storages 152-TK-007/008/009/010

The furnace in the reactor loop uses fuel gas for heat generation to raise temperature & the furnace has some steam generation & superheating coils for heat recovery

4 LOPA WORKSHOP AND FINDINGS

4.1 LOPA Team members & Attendance

LOPA team member is list as below table:

Table 4.1 :- Team List

Department

Expertise

Kien Ha Trung Sr Process Engineer NSRP/TECH/Sec 2

Ivan Stevanus Chandra LOPA Facilitator,

Process Safety

NSRP/ Process Safety

Rodino Reuben G

Tanjuakio

Process Safety Manager

NSRP/ Process Safety

Luong Thien Nguyen Process Safety

Leader

NSRP/ Process Safety

The Attendance is as enclosed in ATTACHMENT 6.1

4.2 HAZOP Node List

HAZOP Node List used for HAZOP study is also the basis for the LOPA study

The unit 020 includes identical equipment with identical design intent but with different tag numbers Hence the hazop and LOPA study was performed for module 1 train 1 The results are to be replicated in Module 2 both trains & 2nd train of Module 1 as Attachment 6.10 of this report

4.3 LOPA Sessions

The LOPA sessions were conducted simultaneously along with the HAZOP as the scenario of RAM 4, 5 or 3E were identified so the sessions are spread over the entire HAZOP schedule

Table 4.2 :- LOPA Sessions

Date

Start/End

Duration days /[Hrs]

Nodes done Description Facilitator Scribe Comment 26/03/24

12/04/24

16/[128] 27 LOPA

Revalidation for Unit 020

Nagesh Gopal Walame

Tran

Ba Toan

Morning of 26 th March was a combined session Utility LOPA

Revalidation team for synchronization The LOPA of Unit 020 was commenced post lunch

on 26/03/24 till completion There was a presentation

on over pressure leading rupture & toxicity HAZARD for 020-V-007

4.4 LOPA Study Summary

The worksheets used for recording the findings are in Attachment 6.3 and recommendations recorded throughout the LOPA workshop are presented in Attachment 6.2 The following Table 4.3 presents the summary of the LOPA workshop proceedings

Table 4.3 LOPA Study Summary

Node number

IPLs SIFs R

Node: 2 Reactor Feed System including

Furnaces

Node: 4 Hot High Pressure Separator

(HHPS) system

Node: 5 High Pressure H2S Absorber

including Recycle Gas Compressor

Node: 6 Hot Low Pressure System including

Cold Low Pressure Flash Drum (CLPFD)

Table 4.3 LOPA Study Summary

Node number

IPLs SIFs R

Node: 8 fractionator overhead pressure 4 10 27 6 2 1 3

Node: 14 Atmospheric Fractionator Bottom

System

Node: 15 Atmospheric Fractionator

Overhead System

Node: 16 Fractionator Overhead

Compressor System

Node: 17 RHDS Diesel Sidecut Stripper

System

Node: 20 Reactor Furnace Convection and

Firing Section

Node: 27 Start-up including Rundown Flash

System

The number of LOPA scenarios for train 1 of Module 1 are 27 in number with following statistics

12 LOPA GAP <= 0.1 Risk fully tolerable and ALARP

10 0.1 < LOPA GAP < = 1 Risk tolerable but not ALARP

For the Module 2 & train 2 of module 1 LOPA scenario number 1 to 4 , 6,7, 10,12,& 14 are applicable

The number of LOPA scenarios for train 2 & Module 2 are 9 in number with following statistics

Scenario count LOPA GAP Description

6 LOPA GAP <= 0.1 Risk fully tolerable and ALARP

2 0.1 < LOPA GAP < = 1 Risk tolerable but not ALARP

A complete listing of the LOPA Recommendations generated during the study is provided in Attachments The LOPA worksheets generated during the study are also provided The LOPA recommendations developed during the study are offered for further review and evaluation These recommendations are not necessarily the only solutions to the risks identified More appropriate solutions may become apparent when an operational review of the recommendations is undertaken Each recommendation must be carefully studied to ensure that it meets the intended goal of solving a risk and that its implementation does not create other hazards or complications

4.5 LOPA Worksheets

The top of the worksheet describes the node number and name

The first column represents the LOPA scenario description The CAT column shows the dominant consequence category such as PPL ( people safety ), AST ( Asset damage ), ENV ( environment ) and COM ( community ) S column shows the consequence severity Next columns show the initiating events which are the initiating causes and their frequency of occurrence per year Conditional modifiers and enabling events with their probabilities are indicated next Safeguard ( non-IPLs) are list of IPLs which are not given any credit for risk reduction All IPLs with their tag number , PFD values , IPL category are given next Next columns shows the LOPA GAPs, viz MEL shows the calculated value of Mitigated Event Likelihood, PFD shows the ratio of MEL to the TEF ( Tolerable Event Frequency ) appropriate for the scenario severity Next column RRF is the reciprocal of the PFD Next two column show

if the scenario meets tolerable and ALARP criteria.PS Time and TSO are additional data to be recorded if available LOPA recommendations with their priority and who is responsible for further action are indicated last

Conditional Modifiers are conditions which if existing at the time of the scenario can affect the outcome of the scenario Conditional Modifiers utilized during the subject study is as follows Control of Personnel ( CoP ) is arrived at as the probability of personnel in affected area calculated as 30 minutes in each shift of 12 hrs This value comes to 0.04 However the value

is to be restricted to 0.1 as per LOPA procedure Hence value of 0.1 is used

The other modifier used is vessel rupture probability as per guidelines in the LOPA SIL methodology & the same is in the range of 0.1 to 0.3

Ignition probability is also used as another parameter wherever applicable & the same is also

as per LOPA SIL methodology & the same is in the range of 0.1 to 0.3

The following table provides the used values of modifiers in different scenarios

Table for modifiers & values in different LOPA scenarios

Modifier

LOPA scenario number

Refer to Attachment 6.3 for LOPA Worksheet

4.6 LOPA Recommendation

Total of 26 recommendations were identified during the LOPA study These are enlisted in Attachment 6.2 under three different categories as described in 4.5 above

It is anticipated that NSRP will convert the recommendations into actions and assign the appropriate action party and track actions to resolution The action undertaken shall either eliminate risk or mitigate the risk by reducing the likelihood or consequences to reduce the risk

to the acceptable level If for any reason an action is not implemented, the justification for this should be documented

4.7 Existing Independent Protection Layers (IPLs)

The LOPA study identified 31 IPLs of the following types in 020 unit:

Count

96 46.83 Alarm

10 4.88 DCS Control

1 0.49 DCS Interlock

29 14.15 PLC Interlock

9 4.39 Mechanical

14 6.83 SOP & Others

The IPL safeguards already at site and given credit for risk reduction are listed in Attachment 6.4