The chemical industry is making products using chemical reactions on derivatives of natural resources, such as natural gas, crude oil, air, etc. In general there are two types of production plants in which these reactions will take place: batch and full continuous processes. Full continuous plants are in general seen as high cost, technically complex and are often reflected as world scale plants. They are mostly located near harbors because high volumes need to be displaced with either ships and/or via pipeline. Batch operations are mostly situated at the end of the synthesis route of high performance products. Although the technology is less complex, the know how is now comprised in the execution of the synthesis (recipe handling) and the quality of the end product.
Both rely on the manufacturing of intermediates which can be either toxic, flammable or even explosive. In any chemical process being run at a large scale, process safety should be well understood in order to avoid serious incidents. As the scale of a process increases beyond lab scale, very specific (physico)chemical aspects of the process will come into play.
This course can be divided in two parts, the first part concerning batch processing and reactive chemical hazards, the second part concerning continuous processing and the associated (mechanical) process hazards.
In the part on batch processing, the focus will be on the hazards which can arise from the chemical reactivity of the products involved in the reaction. This reactivity can produce heat and/or gas, and both can lead to unsafe operation if not properly controlled. Guidelines will be given for:
- the identification of these hazards in early stage,
- general methods to quantify this hazard and the possible consequences, and
- the experimental procedures needed to obtain the necessary data.
Key aspects in process safety like the runaway scenario, criticality classes, proper heat transfer, influence of gas generation, thermal stability, reactive hazards in waste streams,… will be discussed. Examples of chemical reactive incidents in the industry will be used.
In the second part the focus will be more on continuous processing, where other unit operations such as storage tanks and distillation columns are connected to the chemical reactor. These plants are being operated around the clock and others aspect of process safety such as mechanical integrity will play a more prominent role. These plants will typically only be stopped for reasons such as fouling, catalyst deactivation or legal inspections.
Finally and as a red line throughout the course, important process safety concepts will be illustrated and a basic insight will be given in critical management systems such as “Management of Change” and “Incident Reporting”.