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CHAPTER 1

INTRODUCTION

Chemical industry has been traditionally percept to contribute to the presence

of threats to lives. It serves as a source of menace to workers and public as well as to

the environment. Direct harm to human is caused by the industrial related accidents

and the exposure to the hazardous materials involved. On the other hand, chemical

industry may also cause environmental destruction by its large input of greenhouse

gases emissions to the atmosphere. It also results in massive consumption of the

earths infinite resources which, in turn, plays an important role in environmental

destruction. As a result, a global concern has been raised over sustainable

development in order to keep continuous socioeconomic development as well as to

protect the environment.

The broadly accepted definition of sustainable development refers to the

development that meets the needs of the present without compromising the ability offuture generations to meet their own needs (Hassim, 2010). This definition declares

that Human beings are at the top of concerns for sustainable development. Humans

are entitled to a healthy and productive life in harmony with nature (UNCED, 1992)

(Moldan et al., 2012). Sustainable development is a multi-dimensional concept. It is

divided into three pillars which are economic, environmental, and social sustainability

(Hassim, 2010).

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Among the three pillars of sustainability which are the economic,

environmental and social, the environmental sustainability has received far more

attention. Many programs have been launched to support environmental

sustainability. Many, short and long-term commitments have been made by many

governments around the world to support environmental protection related issues. On

the other hand, many chemical companies have joined programs such as Responsible

Care which has been launched since 1985 (Hook, 1996) (Hassim, 2010). The aim of

such programs is to make progress towards sustainability in order to achieve the

betterment of society, environment and economy. The continuous improvement of

environmental, health and safety performance is also an essential target for which

these programs have been launched.

Based on the above-mentioned definition of sustainable development, human

well-being is at the center of concerns in order to achieve sustainable development. It

is also considered as an essential indicator of progress towards development

sustainable (Moldan et al., 2012). Health and safety are top consideration when

assessing the well-being of human. It has been stated by Hassim (2010) that health

and safety are an important part of the integrated responsibility in social sustainability

(Hassim, 2010). Furthermore, (Al-Sharrah et al., 2010) have pointed that health and

safety of workers are also part of sustainability indicators (Hassim, 2010).

Chemical plants are among the workplaces that may adversely affect workers

well-being. The plants also may contribute to impacts upon the environment by the

contaminants releases during either normal plants operation or catastrophic accidents.

Apart from that, chemical plants are undeniably the main source of the growth of

national income. This reflects the impact of such plants on the three pillars of

sustainable development.

Previously in chemical industries, economic and technical aspects used to be

the most important considerations taken into account when making decisions relatedto new process development. However, nowadays safety, health, and environmental

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aspects have been given an increasing attention as essential criteria to be taken into

account in choosing the chemical process route (Hassim and Edwards, 2006).

Based on public image, chemical plants are known as an inherently hazardous

to both workers and community in surrounding area as well as to the environment.

Such an impression becomes worsen after a series of catastrophic events involving

chemical plants including explosions of Flixborough plant in 1974, fires in Piper

Alpha Oil Platform in 1976 and toxic releases in Bhopal in 1984. These accidents

caused an immediate fatalities, severe injuries and serious illnesses to the workers and

public community. As for the environment, the negative impacts on the ecosystem

may be resulted from releases during normal operation or loss of containment due to

catastrophic accidents e.g. the Deep Water Horizon Oil Spill in April 2010.

In an attempt to control the hazards in chemical plants, added-on protective

systems are installed as the most reliable defense system for the plant. However,

inherent safety is a new and better approach that aims to reduce or even to avoid the

hazards inherently rather than controlling them by added-on systems. It is introduced

after the Flixborough explosion, which was later formalized as inherently safer design

(Hassim, 2010). The concept of inherent safety was brought up by Trevor Kletz in

1970s. Following the massive researches related to inherent safety, the idea was

extended to cover also the environment and occupational health aspects. The

integrated consideration of all the three aspects based on inherent safety concept was

later known as inherent safety, health and environment (ISHE) (Hassim and Edwards,

2006).

In relation to evaluation of ISHE at early process design stage, a number of

index methods have been proposed (Hassim et al., 2008). Most works have been

focusing on the development of these index methods for inherent SHE assessment in

chemical process development and design. The idea is to make the process to be

inherently safer, healthier and environmentally friendlier through better selection ofchemicals, operating conditions and technologies.

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Most of the attention has been directed to safety aspect. On the other hand,

occupational health has received limited concern. In integrated ISHE methods health

has always been discussed only as minor part of the other aspects. Among the studies

that focus exclusively on occupational health were conducted by Johnson (2001)

(Occupational Health Hazard Index), and Hassim & Edwards (2006) (Process Route

Healthiness Index) (Hassim and Edwards, 2006).

1.1 Background of study

Several comparison-related studies have been conducted aiming to find if it is

possible to estimate all the SHE properties at inherent level using one single method.

Examples of these studies includes; Rahman et al. (2005) compared ISI (by Edwards

and Lawrence, 1993), another ISI (Heikkila, 1999) and iSafe method (Palaniappan et

al., 2004). Similarly, Hassim and Edwards (2006) compared their PRHI with ISI (by

Edwards and Lawrence, 1993) and EHI (Cave and Edwards, 1997) (Adu et al., 2007).

Adu et al. (2007) have compared 21 SHE index methods (7 safety methods, 4

health, and 10 environmental). Methyl methacrylate (MMA) production was selected

as a case study. They concluded their study and stated that there is no unique merit of

one method over the other in any of the environmental, health and safety aspects. The

appropriate simplicity of a method according to early design phase where it can be

applied is the only merit that separates the methods (Adu et al., 2007).

Hassim et al. (2008) have carried out a study to determine the correlation SHE

properties at inherent level. The study involved 12 SHE index methods four methods

for each. The correlation has been conducted using linear regression. Methyl

methacrylate (MMA) production was selected as a case study. It has been found thatsafety & environment and safety & health factors show the strongest binary

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correlation, whereas, health vs. environment was less correlated. The study also

found that IOHI or ISI method alone can be used as a single index method for

estimating all the EHS properties for route selection in this case study (Hassim et al.,

2008).

Carrying out further studies on correlation between EHS indices is the area of

interest of this research. However in order to totally focus on inherent properties,

only pure inherent based indexes will be considered. Out of the 12 methods, only 6

fall under this category, two for each criterion. Benzene production is the case study

selected for this work. The aim of this correlation is to determine how strong these

indices can be correlated and then to find one index that can be used alone to evaluate

all the EHS properties for route selection in this case study. In addition, the

correlation for MMA production case study was recalculated again, this time only for

those six indices. The results from the MMA case study will be compared to benzene

case study for averaging and validation purpose.

1.2 Problem statement

An arising question is; do the S, H and E properties correlate at inherent level.

That is; is it possible to find a single method that can be used alone to evaluate the

properties of all SHE aspects at inherent level. To find the answer for this question, a

correlation study was conducted to correlate six index methods using three process

routes for benzene production as a case study. Each two methods were selected to

represent one of the three main aspects safety, health and environment.

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1.3 Case study

Benzene is an important product, which is widely used in manufacturing many

products such as tires and rubber. Benzene also is an ingredient of a variety of

painting such as base and top coat paints, lacquers, spray paints, sealers and stains.

Petroleum and oil refineries produce products that contain benzene, such as gasoline,

fuel oils and kerosene. Benzene is used in manufacturing chemical and plastic

products. Examples include resins, adhesives and synthetic products such as nylon,

styrene and Styrofoam. Hence, three process routes for benzene production were

selected as a case study.

The correlation between the six EHS index methods was conducted on three

alternative process routes for manufacturing benzene as a case study. The three routes

are Toluene Hydrodealkylation process (HDA), pyrolysis hydrogenation process route

and catalytic naphtha reforming process route.

1.4 Objective

The aims of this study are:

1. To determine to which extent the EHS properties can be correlated at inherent

level.

2. To determine if it is possible to use only one index to evaluate the EHS properties

at inherent level.

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1.5 Scope

This study will cover a correlation between EHS properties at inherent level.

This study is limited to use six index methods to be used in carrying out this

correlation. Two index methods for each aspect of the three main aspects

(Environment, Health and Safety) will be selected.

Benzene was selected as the case study of this project. Only two process

routes of manufacturing benzene are involved in this study. The two process routes

are; Toluene Hydrodealkylation process (HAD) and pyrolysis process.

The aim of this study is to determine if the EHS properties can be correlated at

the inherent level. Also this study aims to simplify index-based EHS evaluations by

using only one index for the whole EHS evaluation.

1.6 Thesis Organization

The study comprises four chapters beginning with a brief introduction as a

chapter one. In Chapter 2, previous studies and researches related to the sustainability,

inherent safety, and ISHE index methods are presented. The methodology and

calculation methods, equations, relevant ranking and scoring tables, and linear

regression as an analysis method are discussed in Chapter 3. Chapter 4 discusses the

results obtained by applying the selected six index methods on the chosen process

routes of benzene case study. Also the outcomes of the correlation between the six

index methods are discussed in Chapter 4. Finally, conclusion, recommendations for

future works are introduced in Chapter 5.