Implementing a PSM in a New Ethylene Production
Project
Pablo Ricardo Barrera
Braskem – South Basic Petrochemical Unit (UNIB-RS)
Porto Alegre, Rio Grande do Sul, Brazil
[email protected]
ABSTRACT
The process safety management in a petrochemical company is a key factor for
sustainability, since it is intended to prevent or minimize the consequences of a major
accident due to a release of toxic, reactive, flammable or explosive substance from a
process.
This work aims to present an approach to implement a Process Safety Management (PSM)
in the project of a new Ethylene plant that will be constructed at Braskem - Basic
Petrochemical Unit in the South Petrochemical Complex, Brazil and was conceived to
produce Ethylene in an Ethanol basis. The start-up is schedule for September/2010. All the
13 elements of the PSM proposed for this plant were based on OSHA 3132 (29 CFR
1910.119) and have being considered in each phase of the Enterprise: design, pre-startup
and operating phase. The relation between these elements is also presented, the chronology
of implementation and the expected results for each phase. The incorporation of current
practices, considering the 27 and 10 year experience of two existing Ethylene units
(naphtha basis), such as technical standards, operational and management practices, is
also considered an important synergy factor.
1
INTRODUCTION
The process safety management in a petrochemical company is a key factor for
sustainability, since it is intended to prevent or minimize the consequences of a major
accident due to a release of toxic, reactive, flammable or explosive substance from a
process.
Braskem, the leading petrochemical company in Latin America, is committed, since its
foundation, to act in accordance with the principles of sustainable development. Thus, we
decided to build a new ethylene plant from a renewable raw material, ethanol, instead of
traditional plants that use naphtha and condensate. The startup is schedule to September
2010.
The implementation of the process safety management in all phases of the project,
starting with conceptual design, is a key factor to the success of the enterprise.
2
PROCESS SAFETY MANAGEMENT
The following is a schematic representation where the elements of the PSM are
presented in 4 dimensions: Documentation, Analysis, Plans and procedures, Qualification.
The elements were divided between the pre-startup, startup and normal operation. The
relationship between the elements is also presented.
Figure 1- Pre-startup phase.
Figure 2- Transition from pre-startup to operation phase
Figure 3- Operation phase and the learning process
2.1 Process Safety Information
The new ethylene plant used as a technological route the catalytic dehydration of
ethanol, and the basis of design was obtained from a similar plant, which was built in the
60th on a site of Braskem in Maceió-Alagoas and now is deactivated.
An extensive review of the project was undertaken in order to update it in accordance of
current engineering standards. New process flow diagrams (PFD) including material and
energy balances, piping and instrument diagrams (P&Id) and data sheet of equipments are
examples of documentation that were prepared.
In this step, an important factor was the incorporation of Best Practices considering the
27 and 10 year experience of two existing Ethylene units (naphtha basis), such as technical
standards, operational and management practices. Examples of these improvements
include:
1 Adoption of closed drainage systems (sumps)
2 SDCD (philosophy and standard)
3 Strategy for control and protection of compressors (ethylene and propylene
refrigerant)
4 Standard for emergencies combat system (fixed protection)
2.2 Process Hazard Analysis
The project went through an extensive and systematic risk analysis that began with a
preliminary hazard analysis, which involved more than 500 risk scenarios. This step was
performed after the completion of the conceptual engineering design.
By the end of Basic Engineering, extensive HAZOP studies were conducted resulting in
more than 1000 risk scenarios and 300 recommendations for risk mitigation.
For those risk scenarios that presented safety instrumented system (SIS) as a safeguard,
Safety Integrity Level (SIL) studies were performed.
Figure 4- Risk Matrix for Outside Battery Limit (OSBL) PHA studies
Another important study was a quantitative risk analysis to determine the best location
of the new large (3000 m3) ethylene storage sphere. There were three possibilities, two
behind the current cryogenic ethylene tanks and another one near the park spheres. After
this analysis the location was chosen based on financial risks associated.
Industrial area 3
Position 2 (Sphere)
Position 3 (Sphere)
Industrial area 4
Industrial area 2
Tank area 2
Pumps
Industrial area
5
Industrial area 1
Tank area 1
Tank area 3
Pumps
Position 1 (Sphere)
Figure 5- Alternative positions for ethylene storage sphere
2.3 Operating Procedures
Operating procedures are being developed, considering the result of these two previous
steps: Process Hazard Analysis and Process safety information.
These procedures will meet all requirements of OSHA 3132 (PSM) and covers:
- Commissioning;
- Initial startup;
- Normal operations;
- Emergency operations including shutdown;
- Normal shutdown; and
- Startup following a turnaround, or after an emergency shutdown.
Figure 6- Schematic model of Emergency Operating Procedure (example)
2.4 Emergency Planning and Response
The UNIB-RS has a complete and comprehensive system of planning and response to
emergencies, consisting of:
- Material resources: firewater system, fire fighting vehicles and other emergency devices;
- Human resources: professionally trained fire response personnel shift divided in
administrative and shift staff;
- Procedures: pre planning and emergency procedures in ISO format.
For the new plant, was necessary to expand the firefighting water system, and the
development of new procedures for emergency response (pre-planning) specific to the new
plant, especially to emergency response involving ethanol scenarios, which is a polar
substance, different of most hydrocarbons, which are nonpolar.
PRÉ PLANO DE EMERGÊNCIA
PCEM
EQUIPAMENTO
DADOS DO
EQUIPAMENTO
• Diâmetro
interno:4.40mt
•Comprimento:13.20m
• Volume total vaso:
223.2m³
• Volume fase líquida
(60%): 130m³
• PSV: alívio para
flare.
14V54
• Sentido predominante dos ventos: SUDESTE
• Itinerário: RUAS N, 19, M, 18.
• Ruas à isolar: 16/G-19/F-21A/G-N/16-N/21A
DADOS FISICO-QUÍMICOS
• Produto: PROPENO (GÁS)
• P.F. (ºC): -108 ºC
• Temp. de Ignição (ºC): 497 ºC
• Densidade do Líquido (água=1): 0,514 (a 1 atm)
• Densidade Vapor (ar=1): 1,46
• Temp. de Armazenamento (ºC): 38ºC (LIQUÍDO)
• Pressão de Trabalho: 19Kgf/cm²
• Solubilidade em água: APRECIÁVEL
• Limites de explosividade: 2,4 % - 10,1%
• Fórmula: C3H6
• Temp. crítica: 91,8ºC
RECURSOS NECESSÁRIOS
RECURSOS MATERIAIS
• 01 válvula de abertura dos spray’s do • proteção respiratória ( + 06)
14V54/57 entre 13R02A e rua “19” .
• 02 Bombas de AF com
• 02 hidrantes canhões e 01 hidrante vazão de 925 m³/h – Pressão
canhão de 04 bocais na rua 18.
de 12.6kgf/cm².
• 02 canhões willians.
• 01 ambulância.(preventivo).
• 02 margaridas no pipe rack área 14
• Viatura líder.
• 02 mangueira de 2 ½”, 08 mangueiras de 1 • 01 VGE (preventivo)
½”, 04 chaves união storz, 02 derivantes e
04 esguichos de 1 ½” no total.
TOXICIDADE
• ONU: 1077 (Gás)
• LT: asfixiante simples
• Classe: 2,3
•Ação
no
organismo:
(causa
queimadura (fase liquída) nos olhos,
pele, e trato respiratório. Em ambiente
confinado, concentrações altas diminui
o oxigênio e em concentrações
menores causa dor de cabeça e
tonturas.
RECURSOS HUMANOS
• 13 brigadistas da OE Turno.
(01motorista da VGE, 01 brigadista
para acionar spray´s, 01 líder
intervenção e 01 líder resgate,02
coordenadores (líder executivo,
coordenador geral) 06 brigadista para
linha padrão e/ou canhões.
• 01 motorista ambulância.
CENÁRIOS ACIDENTAIS / AÇÃO
VAZAMENTO EM QUALQUER UM DOS FLANGES JUNTO AO VASO:
•
Acionar sistema de sprays para, contenção e diluição do gás;
•
Tentar reaperto do flange se possível, caso contrário, parar 14C01 e 14C21;
•
Isolar vaso através da 14MOV04
•
Despressurizar o vaso enviando produto (fase líquida) através da linha de fundo para 14V51/52/53 e fase gasosa
para flare via PSV's e 14PV86;
•
Injeção de N2;
•
Aplicar neblina d'água para diluição do gás nas áreas adjacentes;
•
Avaliar o deslocamento da nuvem de gás, isolar a área e orientar evasão num raio aproximado de 500m;
VAZAMENTO SEGUIDO DE FOGO:
•
Acionar sistema de sprays na rua 19, para refrigeração do vaso em emergência e do vaso vizinho;
•
Não apagar o fogo;
•
Tentar reduzir sua intensidade com aplicação de neblina d'água ou diminuindo a pressão interna do vaso enviando
produto (fase líquida) através da linha de fundo para 14V51/52/53 e fase gasosa para flare via PSV's e 14PV86;
•
Parar 14C01 e 14C21;
•
Isolar vaso através da 14MOV04;
•
Posicionar o Posto de Comando na rua "M" com 18 e orientar os isolamentos de ruas e definição das Zonas de
Ação;
•
Observar constantemente o resfriamento do vaso com fogo e o vaso vizinho;
EXPLOSÃO DE NUVEM DE GÁS:
•
•
•
•
Parada imediata da produção e abandono de área.
Acionar alarme de emergência "Abandono de Área".
Avisar as demais áreas.
Reavaliar as consequências após explosão e controlar os incêndios secundários(efeito dominó).
•
•
INCÊNDIO TIPO JATO DE FOGO(FLASH FIRE).
Avaliar se há vazamento e eliminá-lo.
Figure 7- Schematic model of Pre Planning (example)
2.5 Pre startup safety review
For this project two Design Review are scheduled, which aims to verify if the safety
aspects are properly addressed, such as recommendations coming from the HAZOP studies
and if the Detailed engineering is being conducted in accordance with the specifications of
Basic engineering. Two Pre startup safety review will also take place, the first one when
project implementation is around 60% and another with 95%, in order to verify if
implementation of the project, Construction and equipment are in accordance with design
specifications allowing the plant for startup.
2.6 Training
For the project, an extensive and comprehensive systematic of training will be
conducted considered all the information compiled in the previous steps.
2.7 Other elements
Again, it is possible to highlight the synergy achieved by the installation of new plant in
a petrochemical complex that already has two ethylene production units. The new plant will
be inserted in a context where PSM elements such as Mechanical Integrity, Work Permit,
Management of Change, Incidents investigation and Compliance audits, have already
established and in use practices.
3
CONCLUSION
Consider the implementation of management tools such as the PSM since the beginning
of a project becomes an imperative key factor for projects success.
All the initial and structured planning in process safety, reduce project costs, and also
ensures a reliable and safe operation.