improving hf alkylation operational safety...

Ian Willetts, Schneider Electric

Cristina Martinez, PDVSA

Improving HF Alkylation Operational Safety Through the Use of Operator Training Simulators

Agenda

� Introduction

� What is Multi-Purpose Dynamic Simulation

� Driving Safe Operation in HF Alkylation Units

� Unique Challenges in developing OTS for HF Alkylation

� PDVSA Puerto La Cruz Experience

Alkylation

●Alkylation is the process of synthesizing isooctane (alkylate) through the reaction of iso-butane with C3 and C4 olefins using either sulfuric or hydrofluoric acid

●Both H2SO4 and HF Acids are extremely hazardous chemicals and require careful management to ensure safety

●Alkylation has grown in importance driven by the growth of FCCs and Coker Units which produce olefins or alkenes from the heavier crude components

●Europe and North America produces approximately one million barrels per day of alkylate in 75% of the world’s HF Alky Units

●SimSci has dedicated solutions to help refiners operate their alkylation units safely and profitably including Operator Training Simulators and the Acid Catalyst Analyzer

What is Multi-Purpose Dynamic Simulation?

Multi-Purpose Dynamic Simulation One Simulator for the Life of the Project

Equipment Design

CheckoutControls

Train Personnel

ImprovePerformance

design testing

• Test control system modifications

• APC Pre-tuning

• Alarm Management

• Control and process design testing

Procedures

• User interface familiarization

• Startup training

• Emergency response training

• I&C diagnostic training

• Validation of operating Procedures

Test instrument ranges

• Control logic and graphic design verification and correction

• Graphic display improvement

• Pre-tune control loops

• Test instrument rangesanalysis

• Process equipment design

• Relief system design

• Control strategy validation

• Process operability analysis

PROCESS

ENGINEERING

CONTROLS

CONFIGURATION

INITIAL

START

PLANT

OPERATION

Driving Safe Operation in HF Alkylation Units

Safety Competency Pyramid

●New operators can learn to start up, shut down and operate the plant in a completely safe environment, on the simulator, before they are entrusted with the real plant

●Can be used to help operating companies with:

˃ Understanding process fundamentals

˃ Preventing accidents

˃ Teaching best practices

˃ Adoption of rules and procedures

˃ Analyzing impact of operations on plant safety

˃ Critical situation preparedness

˃ Routine re-training

˃ Lessons learned analysis

API Recommended Practice 751

●The American Petroleum Institute Recommended Practice Number 751 (Third Edition June 2007) specifically discusses the safe operation of HF Alkylation Units

●Two key requirements of API Recommended Practice 751 are:

1. Maintaining a process hazards management plan involving a process hazards analysis. The RP states that the hazards analysis should consider routine operations; start-up; shutdown; upset and failure conditions and emergencies..

2. Training - Training is required to ensure the persons assigned to the facility possess the required knowledge and skills to carry out their duties, including start-up, shutdown, and emergency procedures

●An Operator Training Simulator can add great value to a company’s hazard management plan and a company’s training program helping to drive the highest level of safety

October 07, 2015 Presented by Cristina Martinez

Improving HF Alkylation Operational Safety

through the use of Operator Training Simulators

CONTENT

Unique Challenges of developing an OTS for HF

Alkylation

PDVSA Puerto la Cruz Experience

OTS SCOPE

DA-2

DA-3

FCC

051-052

ALK

NHT REF

HDT

G91

G95

JET A-1

DSL HDT

RESIDUE

DSL MARINO

PARAFFIN

GLP

MESA 30°

MEREY

16°

AW/SB 40°

PARAFINOSO

Crude Oils PRODUCTS

DA-4

DA-1

DSL

OTS Phase II

Unique Challenges of developing an OTS for HF Alkylation

CONVERSION UNITS

FCCU ALKYLATION

80% AGO

20% AR

DRY GAS

F. iC4

LCO HCO DO

REFORMATE

G95

FUEL

GASAMINE

NAPHTHA

C3C4

ALKYLATE

DOMESTIC

GAS

C4

C3


Amine/Caustic

Treatment

Olefin

From FCCTo Gas System

Fresh IC4

Water

Dryers

T-1

Fresh Acid

IC4 Recycle

ASO/CBM

IC4 from Depropanizer

Acid Rerun Tower T-6

Acid to Reactor

Depropanizer

HF to Acid Recontactor

Accumulator

IC4 Recycle

Isostripper

Propane

Defluorinator Propane

KOH Treater

Alkylate

Alkylate

Product

Butane

Defluorinator

Butane

Debutanizer

HF Stripper

Acid from Recontactor

Acid

Recontactor

DR

-2

D-6

E-41

T-21

T-2

T-22

T-3

D-8E-11

E-42

Acid Settler

Reactor D-4

T-6

T-1

4

T-9

T-1

3

T-7

T-8

T-4

E-15

E-20

Deethanizer

PROCESS DESCRIPTION


AccumulatorD-7

KOH Treater

KOH Treater

Solubility of propane into HF

Fractionation

Feed Conditioning Reaction and

Regeneration

Product Treatment

L-L separation of propane and HF Temp profile and HF-propane separationTemperature decreaseHF content

Schneider-Electric has addressed these challenges by

developing a special thermo calculation set HEXAMER

specifically for this type of process and this is delivered with

the DYNSIM product. The complete solution provides a

perfect environment for executing training exercises

repetitively in a safe environment ensuring effective learning.

HEXAMER


THERMODYNAMIC MODEL CHALLENGE

SCOPE DEFINITION

•Review of P&IDS

•Functional Specification Document

TECHNICAL INFORMATION

• Heat and Mass Balance

• Equipment data sheets

• Controls and Alarms

MODEL DEVELOPMENT

PREFAT TEST

SAT TEST FAT TEST

MODEL FIXES

Definition of timelines,

participation of each department

FINAL MODEL DELIVERY


OTS SOLUTION

OTS SOLUTION

Graphical interface

for operator similar to DCS

Graphical interface

For engineer or instructor



OTSworkers to

operate more

efficiently

CLEAR

UNDERSTANDING

OF PROCESS

DISTURBANCES

highly corrosive acid, lethal if inhaled by humans

MINIMUN

HUMAN

ERROR

OTS

HUMAN

RELIBIALITY

SAFETY

� Phillips Licensor (Now UOP)

HF Catalyst

� Design Capacity: 4500 BPD

� Since 1962 (2271 BPD)

Revamp in 1991 (4500 BPD)

� DCS is ABB MOD300

PLC Refinery HFAU


The operator training was done in

traditional fashion, where

theoretical classes and seminars

were delivered by experienced

senior personnel from PDVSA.

Formal program to train the

operators and new engineers on

the HF Alkylation unit by using the

OTS system


�Personnel is going through different operational scenarios as

in real life but in a safe environment

�Process Engineers make evaluations and continuously update

the operational procedures

�Operators are reproducing process trips or malfunctions to

find causes and implement corrective actions and minimize

future occurrences


is always aware of the danger of catastrophic failure if

the plant is operated with an inadequate I/O ratio

it is possible to show the operator how this operational upset

can occur and what actions he has to perform to successfully

recover the plant from that situation. All these actions have to

be taken repeatedly until the operators feel comfortable of how

to operate the unit


� REACTION TEMPERATURE

� I/O RATIO

� ACID PURITY

� ACID CONSUMPTION

�ACID/HC RATIO

� ALKYLATE OCTANE

KEY OPERATION PARAMETERS

Malfunctions, Scenarios and challenges addressed with the OTS system


INSTRUCTOR VARIABLES @DYNSIM

� Acid loss in the Rerun Tower

�Optimal point of control for the rerun column reduce lose acid

through the bottom, minimize the acid consumption and promote

the reactions efficiency

�Depropanizer overhead pressure is difficult to build up during plant

startup

�The OTS system helps operators to find the optimal way to control

that section during the startup of the plant

�Corrosion problems on the treatment section due to high

n-butane/fluoride rate

�PDVSA is planning to use the simulator for testing of a new way of

operating the debutanizer, to get more volume of n-butane to avoid

corrosion caused by the low velocity trough the heat exchanger

Malfunctions, Scenarios and challenges addressed with the OTS system


Looking to the future

� Refreshing and strengthen knowledge of the experienced staff

at the Alkylation unit

� Test new operational procedures

� Implementation of new control philosophies

� Optimize the operation

� Implement best practices in the refinery operation


Our main project. The target

is to build new process units

to cover the demand of

products (gasoline, jet, diesel)

increasing capacity of the

actual conversion units in

order to meet international

market regulations

DEVELOPMENT OF NEW TECHNOLOGIES

UNDER INTERNATIONAL STANDARDSAPI

ASTM

ASME

Looking to the future


There are numerous ways to provide training to operators and a

holistic training approach will encompass classroom training,

training on the job and various other means. However, state-of-

the-art training with a clear focus on enhancing plant safety

through an operator-centric approach should include an operator

training simulators as a key element.

This argument is supported by the PDVSA Puerto La Cruz Refinery

where the Operator Training Simulator is strongly driving

increased safety at the plant. An Operator Training Simulator is a

critical tool that can be used to provide training well beyond the

control room. Today’s commercial simulation software is now

ready for prime time when it comes to driving improved safety on

HF Alkylation Units.

Conclusion

improving hf alkylation operational safety...

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