The U.S. Chemical Safety and Hazard Investigation Board (CSB) released a contractor report stemming from the 2017 fatal dust explosion at the Didion Milling facility in Cambria, Wis. The document, “Dust Hazard Learning Review,” gathered feedback from industries that handle combustible dust to identify the key barriers to improvement in the control and mitigation of combustible dust hazards.
 

Designed to recycle nitrogen to increase the amount of nitrogen in the process air to 85 percent to render combustion impossible, the fluid-bed drying system has an integral baghouse dust collector set directly above the fluid-bed drying zone to create a sealed system. 

The U.S. Chemical Safety Board (CSB), as part of its investigation into the May 2017 Didion Mill explosion, issued “Call to Action: Combustible Dust” to gather comments on the management and control of combustible dust from companies, regulators, inspectors, safety training providers, researchers, unions and workers affected by dust-related hazards.

This article will discuss how typical powder dryers operate, what hazards they present and strategies that can be used to manage the risk of fire and explosion inside of this equipment. Read the first part of this two-article series to learn about the conditions that allow fires and explosions to occur inside of drying equipment and the potential sources of ignition that can trigger industrial dryer fires and explosions.

Handling and processing of powders at elevated temperatures is widespread in many industries. The range of temperatures associated with these operations varies depending on the nature of the material and the intent of the operation (drying, melting, agglomeration etc.).

Uncontrolled and unplanned fires and explosions in the plant are obviously undesirable.