Process Safety Aspects

A range of reactions have been reported which take place between two solids under the influence of mechanical agitation such as ball milling. A reasonably large range of reachon types has been reported [59]. Concerns over homogeneity and reproducibility at scale plus process safety aspects of the control of exothermic reachons may mean that this technology could only be of interest in a very limited number of cases. 

Percentage of personnel having the process safety aspects of their Job defined in writing X... 

This chapter presented a comprehensive overview of all process safety aspects applicable for revamp projects. It provides a quick reference for practicing engineers and also students. Note the following key points for achieving sustainable revamps. 

Koc, R., Kazantzis, N. K., Ma, Y. H. (2011). Process safety aspects in water-gas-shift (WGS) membrane reactors used for pure hydrogen production. Journal of Loss Prevention in the Process Industries, 24, 852—869. 

In this book we examine the application of the practice of PSSR to the physical plant hardware, software, engineering, and management activities, and documentation associated with operating chemical processes. Although we focus on the ehemical process industries (CPI) and specifically the associated process safety aspects, the concept of PSSR and its benefits apply to almost any human endeavor, espeeially in the manufacturing realm. 

Understanding the behavior of all the chemicals involved in the process—raw materials, intermediates, products and by-products, is a key aspect to identifying and understanding the process safety issues relevant to a given process. The nature of the batch processes makes it more likely for the system to enter a state (pressure, temperature, and composition) where undesired reactions can take place. The opportunities for undesired chemical reactions also are far greater in batch reaction systems due to greater potential for contamination or errors in sequence of addition. This chapter presents issues, concerns, and provides potential solutions related to chemistry in batch reaction systems. 

Contractors If contractors are working at a toller s site, this element of process safety demands that they be informed of any hazards the new toll could present. If contractors are specifically involved with the toll in question and the company is subject to PSM compliance, other aspects of this element must be met. 

Transportation should be considered when assessing risks associated with planned or existing plants. The design of new chemical processing units should include at the earliest opportunity a qualitative or quantitative risk assessment of the whole system including production, use, and transportation in order to minimize overall risk. A brief discussion of the inherent safety aspects of transportation is included in Chapter 5. 

Chapter 8, room processes and aspects, air distribution, safety issues... 

This model is unique in its description of what constitutes a management system, and its effort to address the planning, organizing, implementing, and control aspects of process safety management systems. 

Sociotechnical approach (control of error through changes in management policy and culture) Occupational/process safety Effects of organizational factors on safety Policy aspects Culture Interviews Surveys Organizational redesign Total Quality Management More frequent in recent years... 

New systems or processes may also need to be qualified from an operational safety perspective. This is particularly relevant in the case of chemical synthesis involving exothermic reactions. Critical safety aspects are usually identified using hazard operability or HAZOP assessments and studies. For example, a HAZOP analysis of an exothermic reaction vessel would involve consideration of the consequence of failure of the motors for mixers or circulation pumps for cooling water. Thus, the qualification of such a system would involve checks and assessment to ensure that the system/process can be operated safely and that pressure relief valves or other emergency measures are adequate and functional. 

As with the case of mass, there are several approaches to metrics for this aspect. One can simply sum numbers and/or mass of chemicals possessing hazards in different areas for example, process safety, occupational exposure, or environmental hazard. Typically, most companies will use a banding approach for materials that allows a quick identification of the hazard category, and usually marries hazard with a suggested control approach for example, layers of protection, pressure relief valves, and so on. One is then able to rapidly identify issues and potential opportunities for elimination, substitution, or control. 

Koller, G. (2000) Identification and Assessment of Relevant Environmental, Health and Safety Aspects during Early Phases of Process Development. Technische Wissenschaften Eth Zurich, Zurich. 

Whether voluntarily or not, as companies phase out chemicals of concern, they are subsequently faced with the challenging task of finding alternative chemicals or processes to serve the same desired functions. Simply because a chemical is not a known hazard does not make it benign. To avoid going from the frying pan to the fire so to speak, it is necessary to assess and compare alternatives. In this section we describe several tools and approaches for assessing the human and environmental health and safety aspects of chemicals. They include ... 

Based upon laboratory and mini- or pilot-plant experiments process flow-sheets are prepared that also take environmental and safety aspects into consideration. Studies on these aspects are carried out in parallel with chemistry and engineering research in the form of so-called Integrated Process Development (see Heinzle and Hungerbiihler, 1997). 

Although there are many biocide alternatives available on the market, for example enzyme technology or bio-dispersants, there appears to be a continued requirement for the use of biocides in order to reduce the levels of microbiological contamination entering the paper making process. The increased awareness of environmental and safety aspects will continue to play an important role on the selection of biocides for paper making processes. The use of legislation to select biocides must be done in parallel with each plants internal risk assessment. No one biocide active will meet all the criteria set out by different European countries and hence the use of these actives must be carefully assessed on a plant by plant basis. 

In addition, many other aspects must be considered when developing a catalytic reaction for industrial use these include catalyst separation, stability and poisoning, handling problems, space-time yield, process sensitivity and robustness, toxicity of metals and reagent, and safety aspects, as well as the need for high-pressure equipment. 

Full Scale Production—Reevaluation of chemical reaction hazards Newly revealed reactivity hazards from plant operations Management of changes Update of safety procedures as required Ongoing interaction of process safety with engineering, production, economic, andcommercial aspects of the process... 

In order to prevent incidents, a process plant must not only be well-designed, but also properly operated and maintained. To ensure that all safety aspects receive adequate priority, the commitment to safety from all levels of management is essential. In practice, conflicts of interest may arise between safety and other goals such as production demands and budgets. In these cases, the management attitude will be decisive. In reality, such a conflict of interests is only an apparent one because safety, efficiency, and product quality all depend on a reliable production facility with a low frequency of technical troubles and safety problems. 

Essentially all aspects of chemical process safety, including issues related to chemical reactivity, are dynamic. 

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