New report: managing the risk of combustible gas in drum dryers

The Wood Pellet Association of Canada (WPAC) and the BC Forest Safety Council (BCFSC) have released a new report that summarizes the key actions plant operators can take to manage the risk of combustible gas in drum dryers.

In wood pellet production, there is the potential for the formation and ignition of combustible gas, primarily in dryers and burners. Combustible gas, also known as synthesis gas or syngas, is a mixture of flammable hydrocarbons and volatiles (such as methane), carbon monoxide and hydrogen. Combustible gas is formed when biomass is heated in low-oxygen environments. It can accumulate in enclosed areas, like dryers, ducts, cyclones and piping. Ignition of combustible gas can lead to explosions that cause injuries, facility damage and production downtime.

The report, Combustible Gas Risk Reduction in Wood Pellet Production Drum Dryers, is a result of a bow tie analysis workshop conducted in collaboration with staff at Premium Pellet in Vanderhoof, BC and Kayleigh Rayner Brown, MASc, P.Eng. (Obex Risk Ltd.). Bow tie analysis is a hazard analysis tool that wood pellets and medium-density fibreboard manufacturers have previously used to evaluate combustible dust hazards.

Workshop participants emphasized the critical need for workers to better understand the hazardous scenarios that can arise during upset conditions, start-up, or shutdown, normal operation, and confined space entry activities. It’s also important that critical safeguards, including emergency shutdown procedures, operator training, and confined space entry programs are in place and followed.

The report, available to pellet producers across Canada, reinforces the importance of sharing key learnings among the broader sector. It includes important information including:

• The highest-risk operations and activities,
• Conditions that present the risk of combustible gas ignition,
• Measures to ensure the reliability of critical preventative barriers,
• Actions for operations, and
• Bow tie analysis for each hazardous scenario.

Funding for the workshop and the report was provided by the Wood Pellet Association of Canada and the BC Forest Safety Council.

Other combustible gas resources are available at www.pellet.org/safety/. WPAC’s new Operator Training program also includes a module on combustible dust and gas. Register for this free program at www.wpaclearning.com.

Gordon Murray is the executive director of the Wood Pellet Association of Canada. Bill Laturnus is a senior safety advisor, manufacturing, for the BC Forest Safety Council.