Blue skies, green risk matrices: Managing the hazards associated with air pollution control equipment

The chemical process industry creates myriad chemicals that make up consumer products, industrial feedstocks, and other important end‐uses. However, the manufacturing of these materials often results in the generation of unwanted materials. These unwanted materials can be byproducts, wastes, or any combination. They may pose hazards to the process, equipment, personnel, the environment, or offsite stakeholders. The hazards are related to the nature of the materials and could range from corrosive, toxic, and/or flammable. Processes are designed to accommodate and manage the hazards of these unwanted materials. Yet, equipment and process operations that are intended to manage releases and impacts can sometimes introduce process safety hazards of their own. An example is unwanted emission of vapor/gas through the vent system from a process vessel that, if not contained and destroyed, could be harmful to the environment. These emissions may be collected and conveyed to a thermal oxidizer, flare, or another pollution control device, but doing so often creates a fire and/or explosion hazard that must be managed. This risk is elevated if multiple vessels are manifolded together. This presentation uses case studies to illustrate process safety hazards associated with environmental management and describes mitigation strategies and lessons learned that have been employed to manage the risks.