Protecting modern engineered systems has become increasingly difficult due to their complexity and the difficulty of predicting potential failures. With the added threat of terrorism, the desire to design systems resilient to potential faults has increased. The concept of a resilient system – one that can withstand unanticipated failures without disastrous consequences – provides promise for designing safer systems. Resilience has been recognized in research settings as a desired end product of specific systems, but resilience as a general, inherent, measurable property of systems had yet to be established. To achieve this goal, system resilience was related to an established concept, the resiliency of a material. System resilience was defined as the amount of energy a system can store before reaching a point of instability. The energy input into each system as well as the system’s exergy were used to develop system stress and system strain variables. Process variable changes to four test systems – a steam pipe, a water pipe, a water pump, and a heat exchanger – were applied to obtain series of system stress and system strain data that were then graphed to form characteristic system response curves. Resilience was quantified by performing power-law regression on each curve to determine the variable ranges where the regression line accurately described the data and where the data began to deviate from that power-law trend. Finally, the four test systems were analyzed in depth by combining them into an overall system using the process simulator ASPEN. The ranges predicted by the overall system data were compared to the ranges predicted for the individual equipment. Finally, future work opportunities were outlined to show potential areas for expansion of the methodology.

Protecting modern engineered systems has become increasingly difficult due to their complexity and the difficulty of predicting potential failures. With the added threat of terrorism, the desire to design systems resilient to potential faults has increased. The concept of a resilient system – one that can withstand unanticipated failures without disastrous consequences – provides promise for designing safer systems. Resilience has been recognized in research settings as a desired end product of specific systems, but resilience as a general, inherent, measurable property of systems had yet to be established. To achieve this goal, system resilience was related to an established concept, the resiliency of a material. System resilience was defined as the amount of energy a system can store before reaching a point of instability. The energy input into each system as well as the system’s exergy were used to develop system stress and system strain variables. Process variable changes to four test systems – a steam pipe, a water pipe, a water pump, and a heat exchanger – were applied to obtain series of system stress and system strain data that were then graphed to form characteristic system response curves. Resilience was quantified by performing power-law regression on each curve to determine the variable ranges where the regression line accurately described the data and where the data began to deviate from that power-law trend. Finally, the four test systems were analyzed in depth by combining them into an overall system using the process simulator ASPEN. The ranges predicted by the overall system data were compared to the ranges predicted for the individual equipment. Finally, future work opportunities were outlined to show potential areas for expansion of the methodology.

This study is aimed at exploring new process safety metrics for measuring the process safety performance in processing industries. Following a series of catastrophic incidents such as the Bhopal chemical tragedy (1984) and Phillips 66 explosion (1989), process safety became a more important subject than ever. These incidents triggered the development and promulgation of the Process Safety Management (PSM) standard in 1992. While PSM enables management to optimize their process safety programs and organizational risks, there is an emerging need to evaluate the process safety implementation across an organization through measurements. Thus, the process safety metric is applied as a powerful tool that measures safety activities, status, and performance within PSM. In this study, process safety lagging metrics were introduced to describe the contribution of process related parameters in determining the safety performance of an organization. Lagging metrics take process safety incidents as the numerator and divide it by different process-related denominators. Currently a process lagging metric (uses work hours as denominator) introduced by the Center for Chemical Process Safety (CCPS) has been used to evaluate the safety performance in processing industries. However, this lagging metric doesn't include enough process safety information. Therefore, modified denominators are proposed in this study and compared with the existing time-based denominator to validate the effectiveness and applicability of the new metrics. Each proposed metric was validated using available industry data. Statistical unitization method has converted incident rates of different ranges for the convenience of comparison. Trend line analysis was the key indication for determining the appropriateness of new metrics. Results showed that some proposed process-related metrics have the potential as alternatives, along with the time-based metric, to evaluate process safety performance within organizations.

Assessing hazards due to energetic or reactive chemicals is a challenging and complicated task and has received considerable attention from industry and regulatory bodies. Thermal analysis techniques, such as Differential Scanning Calorimeter (DSC), are commonly employed to evaluate reactivity hazards. A simple classification based on energy of reaction (-H), a thermodynamic parameter, and onset temperature (To), a kinetic parameter, is proposed with the aim of recognizing more hazardous compositions. The utility of other DSC parameters in predicting explosive properties is discussed. Calorimetric measurements to determine reactivity can be resource consuming, so computational methods to predict reactivity hazards present an attractive option. Molecular modeling techniques were employed to gain information at the molecular scale to predict calorimetric data. Molecular descriptors, calculated at density functional level of theory, were correlated with DSC data for mono nitro compounds applying Quantitative Structure Property Relationships (QSPR) and yielded reasonable predictions. Such correlations can be incorporated into a software program for apriori prediction of potential reactivity hazards. Estimations of potential hazards can greatly help to focus attention on more hazardous substances, such as hydroxylamine (HA), which was involved in two major industrial incidents in the past four years. A detailed discussion of HA investigation is presented.

In the area of process safety, many efforts have focused on studying methods to prevent the transition of the state of the system from a normal state to an upset and/or catastrophic state, but many unexpected changes are unavoidable, and even under good risk management incidents still occur. The aim of this work is to propose the principles and factors that contribute to the resilience of the chemical process, and to develop a systematic approach to evaluate the resilience of chemical processes in design aspects. Based on the analysis of transition of the system states, the top-level factors that contribute to Resilience were developed, including Design, Detection Potential, Emergency Response Planning, Human, and Safety Management. The evaluation framework to identify the Resilience Design Index is developed by means of the multifactor model approach. The research was then focused on developing complete subfactors of the top-level Design factor. The sub-factors include Inherent Safety, Flexibility, and Controllability. The proposed framework to calculate the Inherent Safety index takes into account all the aspects of process safety design via many sub-indices. Indices of Flexibility and Controllability sub-factors were developed from implementations of well-known methodologies in process design and process control, respectively. Then, the top-level Design index was evaluated by combining the indices of the sub-factors with weight factors, which were derived from Analytical Hierarchical Process approach. A case study to compare the resilience levels of two ethylene production designs demonstrated the proposed approaches and gave insights on process resilience of the designs.

Resumo: Uma reação descontrolada pode levar a uma série de efeitos, como o transbordo do conteúdo de um reator e até mesmo à sua ruptura, e é fonte de constante atenção dos profissionais de engenharia que atuam na indústria química. Se materiais inflamáveis participam ou são produtos da reação, a ruptura do vaso pode causar fogo e explosão. As ondas de choque e o "efeito míssil" resultante dessa explosão podem causar sérios danos materiais e às pessoas. Se materiais tóxicos estão envolvidos pode haver a formação de nuvem de gás tóxica. O presente trabalho discorre sobre o mecanismo exotérmico das reações químicas e sobre o sistema de transferência de calor em reatores encamisados como ferramentas de suporte ao gerenciamento de segurança de processos químicos industriais. Salienta, também, a importância do gerenciamento das modificações dos processos e instalações, cuja falta contribui com os acidentes industriais, uma vez que alteram o nível de segurança original de um projeto. A apresentação do estudo de caso de um incidente relacionado com reação química descontrolada permite a aplicação dos conceitos de reações exotérmicas, transferência de calor e segurança de processo no gerenciamento dos riscos e manutenção da segurança das instalações e das pessoas. Conclui-se, então, que é importante o envolvimento dos profissionais das diferentes áreas como: projetos, manutenção, produção, tecnologia de produtos, segurança do trabalho e meio ambiente, na segurança das instalações industriais. Esse inter-relacionamento é uma das formas de assegurar a sustentabilidade empresarial e social por meio da preservação das instalações e da integridade física das pessoas. / Abstract: A runaway reaction can result in serious effects, since a process-vessel overflow until its rupture. It is a dauly concern of the engineers working in chemical industries. If flammable products are present or if they are finished products of the process, the vessel rupture can result in fire and explosion. Installations and people can suffer consequences of the shock wave and missile effect of this explosion. If toxic products are involved, it can cause a toxic gas cloud. This work present the kinetic parameters of exothermic reactions and heat transfer in process vessel jackets as a tool for process safety management in chemical industries. It mentions also the needs of management of changes, whose absence can contribute to industrial incidents once they can change the original safety level of the projects. The case study, an incident related to a runaway reaction, allows the application of exothermic reactin concepts, as well heat transfer and process safety management. Risk assessment concept and its importance in maintaining the installation and people's safety level are also described. Finally, it is noticed how important is the commitment of experts from different departments, asproject, maintenance, production, product technology, occupational safety and environmental protection, to guarantee industrial process safety. This inter-departmental relationship is a way to warrantee business and social sustainability once it maintains the safe facilities and the people's health. / Orientador: José Antonio Perrella Balestieri / Coorientador: Paulo Magalhães Filho / Banca: João Andrade de Carvalho Júnior / Banca: Messias Borges Silva / Mestre

Made available in DSpace on 2014-06-11T19:30:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-02Bitstream added on 2014-06-13T18:40:03Z : No. of bitstreams: 1 agostini_ms_me_guara.pdf: 1053270 bytes, checksum: 333773ee7fb2c0c333504f2f2b92b553 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Uma reação descontrolada pode levar a uma série de efeitos, como o transbordo do conteúdo de um reator e até mesmo à sua ruptura, e é fonte de constante atenção dos profissionais de engenharia que atuam na indústria química. Se materiais inflamáveis participam ou são produtos da reação, a ruptura do vaso pode causar fogo e explosão. As ondas de choque e o efeito míssil resultante dessa explosão podem causar sérios danos materiais e às pessoas. Se materiais tóxicos estão envolvidos pode haver a formação de nuvem de gás tóxica. O presente trabalho discorre sobre o mecanismo exotérmico das reações químicas e sobre o sistema de transferência de calor em reatores encamisados como ferramentas de suporte ao gerenciamento de segurança de processos químicos industriais. Salienta, também, a importância do gerenciamento das modificações dos processos e instalações, cuja falta contribui com os acidentes industriais, uma vez que alteram o nível de segurança original de um projeto. A apresentação do estudo de caso de um incidente relacionado com reação química descontrolada permite a aplicação dos conceitos de reações exotérmicas, transferência de calor e segurança de processo no gerenciamento dos riscos e manutenção da segurança das instalações e das pessoas. Conclui-se, então, que é importante o envolvimento dos profissionais das diferentes áreas como: projetos, manutenção, produção, tecnologia de produtos, segurança do trabalho e meio ambiente, na segurança das instalações industriais. Esse inter-relacionamento é uma das formas de assegurar a sustentabilidade empresarial e social por meio da preservação das instalações e da integridade física das pessoas. / A runaway reaction can result in serious effects, since a process-vessel overflow until its rupture. It is a dauly concern of the engineers working in chemical industries. If flammable products are present or if they are finished products of the process, the vessel rupture can result in fire and explosion. Installations and people can suffer consequences of the shock wave and missile effect of this explosion. If toxic products are involved, it can cause a toxic gas cloud. This work present the kinetic parameters of exothermic reactions and heat transfer in process vessel jackets as a tool for process safety management in chemical industries. It mentions also the needs of management of changes, whose absence can contribute to industrial incidents once they can change the original safety level of the projects. The case study, an incident related to a runaway reaction, allows the application of exothermic reactin concepts, as well heat transfer and process safety management. Risk assessment concept and its importance in maintaining the installation and people's safety level are also described. Finally, it is noticed how important is the commitment of experts from different departments, asproject, maintenance, production, product technology, occupational safety and environmental protection, to guarantee industrial process safety. This inter-departmental relationship is a way to warrantee business and social sustainability once it maintains the safe facilities and the people's health.

Process Safety Management (PSM) is concerned with the safe handling of products, safe production of products and the safe operation of the process as confirmed by Thrower (2013). The Occupational Safety and Health Administration (OSHA) (2012) promulgated the PSM standard in 1992, which incorporated fourteen elements, to decrease the occurrence of process safety incidents. Walt and Frank (2007) described the cracks in the implementation of PSM programs, emanating from major process safety incidents and compliance audits. This was confirmed by the decaying process safety performance observed in recent years. It was thus proposed that an analysis into the diverse process safety incident causes and its comparison against the implemented OSHA PSM program, would suggest its associated shortcomings. The aim of the study was to determine the most effective approach to implement and sustain PSM in an organisation to prevent and manage the occurrence of major industrial catastrophes. A semi-qualitative study was conducted through the employment of a survey questionnaire and published incident investigation reports. A total of fifty random process safety incidents were interpreted from published and accredited secondary literature. Most of the secondary literature was obtained from the Health and Safety Executive (HSE) and Centre for Chemical Process Safety (CCPS) databases. From the study findings, Mechanical Integrity (MI) failures were found to significantly and consistently contribute to process safety incidents. Further analysis specifically concluded that equipment or control failure was the significant cause. Employee Participation (EP) was found to statistically correlate with the other elements. The researcher found that literature agreed with the aforementioned findings and this study verified that the EP element was instrumental in the implementation of the other elements. The researcher used literature to confirm that safety culture and leadership commitment was crucial to effective and sustainable PSM programs. The case study analysis validated this observation. Therefore the most effective approach to implement and sustain PSM was to adopt the DuPont, Centre for Chemical Process Safety (CCPS), Risk Based PSM framework or Energy Institute (EI) models. To conclude, this study was effective as all the objectives and the aim was achieved. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014

Process Safety Management (PSM) is concerned with the safe handling of products, safe production of products and the safe operation of the process as confirmed by Thrower (2013). The Occupational Safety and Health Administration (OSHA) (2012) promulgated the PSM standard in 1992, which incorporated fourteen elements, to decrease the occurrence of process safety incidents. Walt and Frank (2007) described the cracks in the implementation of PSM programs, emanating from major process safety incidents and compliance audits. This was confirmed by the decaying process safety performance observed in recent years. It was thus proposed that an analysis into the diverse process safety incident causes and its comparison against the implemented OSHA PSM program, would suggest its associated shortcomings. The aim of the study was to determine the most effective approach to implement and sustain PSM in an organisation to prevent and manage the occurrence of major industrial catastrophes. A semi-qualitative study was conducted through the employment of a survey questionnaire and published incident investigation reports. A total of fifty random process safety incidents were interpreted from published and accredited secondary literature. Most of the secondary literature was obtained from the Health and Safety Executive (HSE) and Centre for Chemical Process Safety (CCPS) databases. From the study findings, Mechanical Integrity (MI) failures were found to significantly and consistently contribute to process safety incidents. Further analysis specifically concluded that equipment or control failure was the significant cause. Employee Participation (EP) was found to statistically correlate with the other elements. The researcher found that literature agreed with the aforementioned findings and this study verified that the EP element was instrumental in the implementation of the other elements. The researcher used literature to confirm that safety culture and leadership commitment was crucial to effective and sustainable PSM programs. The case study analysis validated this observation. Therefore the most effective approach to implement and sustain PSM was to adopt the DuPont, Centre for Chemical Process Safety (CCPS), Risk Based PSM framework or Energy Institute (EI) models. To conclude, this study was effective as all the objectives and the aim was achieved. / MIng (Development and Management Engineering), North-West University, Potchefstroom Campus, 2014

Process monitoring in the chemical and other process industries has been of great practical importance. Early detection of faults is critical in avoiding product quality deterioration, equipment damage, and personal injury. The goal of this dissertation is to develop process monitoring schemes that can be applied to complex process systems. Neural networks have been a popular tool for modeling and pattern classification for monitoring of process systems. However, due to the prohibitive computational cost caused by high dimensionality and frequently changing operating conditions in batch processes, their applications have been difficult. The first part of this work tackles this problem by employing a polynomial-based data preprocessing step that greatly reduces the dimensionality of the neural network process model. The process measurements and manipulated variables go through a polynomial regression step and the polynomial coefficients, which are usually of far lower dimensionality than the original data, are used to build a neural network model to produce residuals for fault classification. Case studies show a significant reduction in neural model construction time and sometimes better classification results as well. The second part of this research investigates classification trees as a promising approach to fault detection and classification. It is found that the underlying principles of classification trees often result in complicated trees even for rather simple problems, and construction time can excessive for high dimensional problems. Fisher Discriminant Analysis (FDA), which features an optimal linear discrimination between different faults and projects original data on to perpendicular scores, is used as a dimensionality reduction tool. Classification trees use the scores to separate observations into different fault classes. A procedure identifies the order of FDA scores that results in a minimum tree cost as the optimal order. Comparisons to other popular multivariate statistical analysis based methods indicate that the new scheme exhibits better performance on a benchmarking problem.