Insights for Safer, More Productive Fuel Pellet Production
New eBook: Taking the Mystery Out of Combustible Dust Control
Section 1 – What’s the Risk of Combustible Dust?
- Safety
- Productivity
- Compliance
Section 2 – How to Manage Combustible Dust
- Manual Housekeeping – In-House
- Manual Housekeeping – Vendor-Supplied
- Industrial Dust Control Fans
- What About Dust Collection Systems?
“For all wood pellet manufacturers,” explains Andy Galis, Operations Manager at Greene Team Pellet Fuel Company, “the number one challenge is controlling combustible dust, especially the dry powder-like dust. Despite our best efforts to contain the dust, it still becomes airborne—and that is where the issue is.”
Galis explains, “We did some calculations for our mill, and even if we contained 99.99% of the dry dust going into the pellet mill, that would still lead to over 130 pounds of dry dust becoming airborne per week from each pellet mill.”
“And this dust is highly flammable,” Galis continued. “Once moisture content of the dust drops below 25% H2O, you have the chance for an explosion. Our dust typically exits the dryer around 10% H2O. It’s the smallest pieces that escape suction, and these are typically around 3% H2O, making them even more dangerous. Once the dust is that dry, we treat it like gasoline.”
SonicAire Fan Systems Blow Other Solutions Away
“The key to preventing combustible dust events in pellet manufacturing is keeping the airborne dust from settling on elevated horizontal surfaces,” notes Galis. “If an explosion were to happen, that dust gets rattled off the horizontal surface and then could potentially fuel a secondary (typically more dangerous) explosion.”
According to Galis, “The way to prevent this is with SonicAire oscillating fans. We installed four in our facility, and we’re amazed at how clean the overhead areas are staying. There is practically zero dust in the rafters. We couldn’t be happier with the performance of the SonicAire fans. It makes our plant much safer.”
What is Combustible Dust?
A layer of dust equal to the thickness of a single paper clip can have the capacity to explode, according to OSHA and the NFPA. And according to the annual Combustible Dust Incident Report, there were 194 combustible dust events in the United States in 2018, resulting in 39 injuries and one fatality. A 2018 U.S. Chemical Safety Board (CSB) report recorded a total of 59 fatalities associated with combustible dust incidents over the previous 11 years.
No single sector of industry is responsible for these tragedies. The CSB has reported dust explosions across multiple industries, including lumber, food, plastics, metal, chemical, boat building and electrical manufacturing. Types of dusts include, but are not limited to metal dust, such as aluminum and magnesium; wood dust; plastic or rubber dust; fiber; lint; biosolids; coal dust; organic dust, such as flour, sugar, paper, soap, and dried blood; and dusts from certain textiles. In fact, OSHA has identified over 130 sources of dust that can create the potential for combustible dust events. It’s an issue that is present across the marketplace.
Industry facility managers have responded to the problem of combustible dust with improved housekeeping measures to help mitigate the risk of these disasters occurring. Unfortunately, manual methods and dust collection systems typically aren’t enough to keep up with the accumulation of dust. These manual cleaning methods are also costly and difficult to manage, often requiring shut-downs for manufacturing and significant ongoing maintenance budgets.
How SonicAire Can Help
Fortunately, a better solution for your combustible dust challenges is available. SonicAire’s industrial dust control fans offer a proactive approach. This precision dust-control technology prevents combustible dust accumulation, effectively mitigating the risk of disaster.
The SonicAire Solution
SonicAire proprietary technology combines two methods to control dust flow.
SonicAire fans use high-velocity airflow to clean overhead areas. The strength of this airflow effectively prevents the accumulation of combustible dust particles on overhead structures in the facility.
Typical airflow includes upward thermal currents which naturally lift and carry particles to overhead areas of facilities, where dust quickly accumulates and can become a fire hazard. SonicAire industrial dust control fans prevent these upward thermal currents from holding dust in the air.
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Taking the Mystery Out of Combustible Dust Control
Insights for Safer, More Productive Fuel Pellet Production
FAQs on Combustible Dust
How can dust explode?
Five conditions must be present to cause a combustible dust event. This is referred to as the “Dust Explosion Pentagon.”
- Dust: An application that generates dust.
- Dispersion: Accumulated dust that has spread over the area to form a suspended dust cloud.
- Confinement: Interior conditions that trap the dust cloud.
- Oxidant: Oxygen in the surrounding air.
- Ignition source: This could be something as minor as static electricity or a spark from metal scraping metal.
Here’s how the Dust Explosion Pentagon works: As products are created or handled, the process inevitably creates dust (#1), which then travels on air currents and settles on various equipment and structural elements in the surroundings. In a confined area (#3), such as a manufacturing facility, the dust can also become suspended (#2) in the air (#4). Open flames, a spark from equipment, or even extreme heat can provide the ignition source (#5) to complete the pentagon.
When this happens, the suspended, contained dust can explode. This can ignite layers of dust that have accumulated in the facility, further spreading the fire.
What are primary and secondary combustible dust explosions?
As referred to in the previous question, when combustible dust ignites, it can cause more than one event. When the pentagon is complete, the first explosion occurs. This is referred to as the primary explosion.
This explosion may disturb or loosen other accumulated dust in the area. As this dust forms another cloud, it ignites as well. This explosion, referred to as a secondary dust explosion, can cause more destruction than the initial one.
These explosions and subsequent fires can cause devastating structural damage, personal injury and loss of life. Between 2006 and 2017, combustible dust incidents in the U.S. resulted in 66 fatalities and 337 injuries, according to reports by the Chemical Safety and Hazard Investigation Board (CSB).
What is deflagration?
Deflagration is simply the heating of a material until it rapidly burns. It involves the release of heat by a burning substance, which ignites and spreads fire. A gas stove and the burning of gasoline in an automobile are common, safe examples of deflagration. During a combustible dust event, deflagration happens so quickly that it produces pressure that can cause explosions.
What regulations guide combustible dust safety and compliance?
For safe and legal operation, facilities must adhere to standards set by OSHA and the National Fire Protection Association (NFPA). Several Federal OSHA standards are mandatory, and many states have adopted OSHA-approved plans that adhere to these standards.
The standards set by the NFPA are created by experts in fire safety. While their recommendations are not legally binding, the NFPA standards are often used to create OSHA state and federal regulations. The most recent standard set by the NFPA is NFPA 652: Standard on the Fundamentals of Combustible Dust. This document includes requirements for the completion of dust hazard analyses (DHA) as well as hazard management steps for mitigation and prevention.
How can facility managers prevent combustible dust events?
Appropriate housekeeping measures are key to the prevention of combustible dust events. Facility managers can take proactive steps to minimize dust accumulation and mitigate risk.