Risk Analysis and Control for Industrial Processes - Gas, Oil and Chemicals

A System Perspective for Assessing and Avoiding Low-Probability, High-Consequence Events

Hans J Pasman

• Publisher: Butterworth-Heinemann
• Year: 2015
• Print ISBN: 9780128000571
• eBook ISBN: 9780128009123
• Topic: Technologie et ingénierie
• Subtopic: Ingénierie de la chimie et de la biochimie

Risk Analysis and Control for Industrial Processes - Gas, Oil and Chemicals provides an analysis of current approachesfor preventing disasters, and gives readers anoverview on which methods to adopt.The book covers safety regulations, history and trends, industrial disasters, safety problems, safety tools, and capital and operational costs versus the benefits of safety, all supporting project decision processes.Tools covered include present day array of risk assessment, tools including HAZOP, LOPA and ORA, but also new approaches such as System-Theoretic Process Analysis (STPA), Blended HAZID, applications of Bayesian data analytics, Bayesian networks, and others. The text is supported by valuable examples to help the reader achieve a greater understanding on how to perform safety analysis, identify potential issues, and predict the likelihood they may appear.- Presents new methods on how to identify hazards of low probability/high consequence events- Contains information on how to develop and install safeguards against such events, with guidance on how to quantify risk and its uncertainty, and how to make economic and societal decisions about risk- Demonstrates key concepts through the use of examples and relevant case studies

Chapter 1

Industrial Processing Systems, Their Products and Hazards

Abstract

Major risks posed by process industry are caused by different types of hazard potential. High-consequence risk means that the hazard will have impact over a substantial distance from a source. Possible effects on people and the environment can be by fire, blast, fragments, and also by spread of toxic materials. As an introduction to the next chapters, accident events are described with common substances such as ammonium-nitrate fertilizer, gasoline, and liquefied petroleum gas. Also, dust explosions, reactor runaway in synthesis processes of, for example, pharmaceuticals, and transportation accidents with hazardous materials and pipelines are described. These substances are needed to energize our mobility and to provide for our foodstuffs, clothing, and construction. Although ways were found to produce and handle them relatively safely, we should do better. For this, it is imperative that predictive risk analysis is performed and risks reduced to an adequate level.

Keywords

BLEVE; Detonation; Hazard potential; Hazardous materials; Hazardous substance properties; Industrial process accidents; Risk; Runaway; Transportation risks; Vapor cloud explosion

Accidents will happen, but forewarned is forearmed.

Eighteenth-century English proverb

Introductory remarks

Dealing with high-consequence, low-probability process industry risk sources, exposing their immediate environment to major hazards and acute effects, ought to start with discussing the dreadful tragedy caused by an accident in the Union Carbide plant in Bhopal, India, in 1984. It is certainly not the purpose here to describe this catastrophe in any detail, but this largest of all industrial disasters shall be mentioned. A toxic cloud of methyl-isocyanate escaped from a storage tank after it was heated up in a decomposition reaction with clean water (a so-called runaway reaction). The water entered the tank by accident. Due to the low wind speed and relatively cool night conditions, the growing cloud stayed low near the ground while slowly drifting from the plant to an adjacent neighborhood of migrant makeshift housing in which many slept. The cloud caused thousands of fatalities and many more suffered from toxic effects, some of which continue to this day. For complete details of this accident, see Lees' Loss Prevention in the Process Industries¹ or books especially about the case such as by Shrivastava² or Pietersen.³ The underlying nontechnical causes of the disaster are of a nature that still may be found today, such as economic slump, a shrinking market, competition pressure, cost cuts, an almost endless row of short-staying top managers, downsizing of personnel and a shortage of competent employees, bad maintenance, miscommunication, neglected training of safety and emergency procedures, and a local government not having the strength to maintain a strict policy with respect to industrial safety and environmental protection. Fortunately, over the years our know-how to arrange preventive and protective measures has grown tremendously, and this book wants to demonstrate what has been achieved as well as what methods we can further develop to cope with the complexity of technology and organization. We need goods that industry produces, but ethics require that everything shall be done to prevent harm of employees or the public.

In this chapter, a quick “tour d'horizon” will be made qualitatively to show the effects of various hazardous phenomena that underlie the risks of processing systems and their products, which we shall encounter in the rest of the book. We give brief examples of disasters caused by some known products that are indispensable to our lives, such as mineral fertilizers, car fuels, and pharmaceuticals. These substances can exhibit nasty properties when brought into certain conditions of dispersal, heat, confinement, and contamination. Of course, industry tries as much as possible to avoid using materials with distinct hazardous properties such as high toxicity and explosiveness/flammability, but lack of better substitutes, and economics, can leave not much choice on practical grounds. Despite the hazardous properties of many materials, the process/chemical industry belongs to one of the safest industrial sectors in the world. The fact that their reputation is often perceived as bad may have much to do with past disasters and that, when rare disasters do happen, they can be on a large scale. In addition, most people are not familiar with the methodology of how hazards can be identified and how well these can be controlled so as to minimize the associated risks. This book aims to contribute to a better understanding of these issues and to indicate ways to make further progress.

This chapter is written particularly for those without the substantial background in chemistry and physics that determines the hazardous potentials of substances, while for specialists it may present a quick overview of the relevant aspects. The hazard potential we will consider is one that may impact over a substantial distance from a source. It can be physical, for example, water in contact with hot, molten metal; it can be a toxic hazard to life in the environment, for example, due to a large spill of crude oil or a radioactive one by an escape of nucleides. The examples we shall describe in this chapter are mostly hazards due to energy release by a chemical (explosive) decomposition or by combustion. Details on properties and mechanisms can be found in an abundance of literature, while for further guidance, many details and references in Lees' Loss Prevention in the Process Industries¹ is recommended. Those who do not need all of the details and may be afraid to lose themselves in 3600 pages can opt for consulting the more modest Lees' Process Safety Essentials.⁴ Note that throughout the book, when process safety is mentioned, it is meant to include plant safety. In the strict sense of the word, process is only the producing mechanism, while plant has the connotation of the area, the premises, where the processes influenced by human and organizational factors take place. In fact, our scope will be even wider because we shall also include the risks of storage and transportation.

The tour starts with the process of nitrogen fixation to form ammonia and the production of ammonium nitrate, which are the basic ingredients of fertilizers without which the world population cannot be fed. Ammonia is a gas, toxic to humans, that can explode when mixed with air; ammonium nitrate is a solid and can explode in all three types of possible, chemically energized explosions. It has produced disastrous accidents after being involved in a fire, being contaminated, or being overheated by other means. Several case histories will be briefly described that will provide insight into the complex phenomena one has to deal with and which will be further explained in Chapter 3. Then we turn to fuels, or rather energy carriers: gasoline, natural gas, liquefied petroleum gas (LPG), and hydrogen. Due to the massive quantities needed to keep the world moving and heated, one after the other of these fuels has been involved in explosions, which may display some similar effects but can also be distinctly different in the way they develop. Next, we shall turn to dust explosions and the many combustible materials that have surprised people with the vigorous way “innocent” substances such as sugar and sawdust can explode and harm victims. Further, we shall look at pharmaceutical materials and the reactor runaway events that can occur in their preparation and the damage this can cause. Finally, a few recent transportation accidents will be briefly reviewed.

For those who are interested in an historical overview of industrial disasters that have occurred, there are the lists on Wikipedia⁵ and of Abdolhamidzadeh et al.⁶ The latter is focused on 224 domino-effect accidents—when a mishap starts on a small scale but then escalates via surrounding chemicals, process equipment, or neighboring plants. This list provides an overview of cases from various parts of the world and ones with no fatalities but is missing nondomino cases. As part of Marsh Insurance Ltd, Marsh's Risk Consulting Practice publishes compilations of the largest 100 accidents in the hydrocarbon-chemical industry.⁷ As an insurer, Marsh obtains an overview of insured property losses; examples of losses in two sectors over a period from 1971 to 2011 are shown in Chapter 9, Figure 9.1. In Chapter 3 (Section 3.6.2), a number of incident databases are mentioned.

1.1. General global outlook

The world's population has grown numerically, and rapidly, during the last century; this is due in part to the fast-advancing capabilities of medical care. The expectation is that in due time the number of inhabitants on earth will decline; in fact, the growth rate has already fallen to a current value of 1.1% p.a. Nevertheless, between 1990 and 2010 the world population still increased by 30% or in absolute numbers from 5.3 to 6.9 billion. The projection of long-term decline is partly based on the belief that the standard of living in general will increase so that the immediate fear of starving to death in old age, when not looked after by one's progeny, disappears and the necessity to produce a wealth of descendants reduces. The trend of decreasing population growth can clearly be seen in all industrialized countries, even to such an extent that in a number of countries the population is already shrinking. However, there is only one way to raise the standard of living: industrializing and generating the power to drive it all.

Agriculture was of course a solution to mankind when the hunter-scavenger ran out of resources, but with the present size of the earth's population, agriculture without an industrial base would fall very short of being able to feed us all. In fact, our survival is entirely dependent on the process industries. The basic ingredient for artificial fertilizer is ammonia, a compound of the elements nitrogen and hydrogen (NH₃), which had been produced on an industrial scale as a side product in coal distillation, the “mother” of industrial chemistry. As the yield was very limited, other production routes were sought. The solution was direct synthesis from the rather inert gas nitrogen, which makes up about 80% of the air around us, and hydrogen to form ammonia. This reaction is called nitrogen fixation. Part of the ammonia can then be oxidized to nitric acid, with which it is then combined with the remaining ammonia to form ammonium nitrate (AN), the main constituent of mineral fertilizers. The production of pure nitrogen and hydrogen...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Foreword
• Preface
• Acknowledgments
• Chapter 1. Industrial Processing Systems, Their Products and Hazards
• Chapter 2. Regulation to Safeguard against High-Consequence Industrial Events
• Chapter 3. Loss Prevention History and Developed Methods and Tools
• Chapter 4. Trends in Society and Characteristics of Recent Industrial Disasters
• Chapter 5. Sociotechnical Systems, System Safety, Resilience Engineering, and Deeper Accident Analysis
• Chapter 6. Human Factors, Safety Culture, Management Influences, Pressures, and More
• Chapter 7. New and Improved Process and Plant Risk and Resilience Analysis Tools
• Chapter 8. Extended Process Control, Operator Situation Awareness, Alarm Management
• Chapter 9. Costs of Accidents, Costs of Safety, Risk-Based Economic Decision Making: Risk Management
• Chapter 10. Goal-oriented versus Prescriptive Regulation
• Chapter 11. The Important Role of Knowledge and Learning
• Chapter 12. Risk, Risk Perception, Risk Communication, Risk Acceptance: Risk Governance
• Chapter 13. Conclusions: The Way Ahead
• Index