The Harrington Group

The Dangers of Wood Pellet Plant Facilities

Posted on Thursday, January 9th, 2014

Photo: Frieda Squires/The Providence Journal

An explosion occurred on August 20, 2013 at Inferno Pellets Co. in East Providence, Rhode Island and the resulting fire, which spread throughout most of the 300,000 square-foot factory, took about four hours for firefighters to bring under control. One employee was injured by the explosion and subsequently released from Rhode Island Hospital after being treated for first and second degree burns.

In September 2013, another wood pellet incident was reported. This time, a dust explosion occurred at the Nature’s Flame facility in Rotoakawa, New Zealand. Also in September, an explosion incident was reported at the Anderson Hardwoods Pellet facility in Louisville, Kentucky, where at least one person was taken to the hospital with injuries.

Going back a little further, on October 20, 2011, an explosion and fire occurred at the New England Wood Pellet facility in Jaffrey, New Hampshire, which originated in the facility’s dust conveyor system. The large ensuing fire took approximately 14 hours to extinguish by over 100 firefighters from 14 different departments. OSHA was brought in to investigate the incident, which resulted in the company being fined a total of $147,000 for safety violations including, “poor dust collection system design” and “no explosion prevention / protection”.

In June of 2011, a dust explosion and resulting fire knocked down operations for a month at the Georgia Biomass facility near Waycross, Georgia, one of the world’s largest wood pellet manufacturing facilities. The $175 million plant had only been open for about a month when the incident occurred. According to plant manager, Ken Ciarletta, an investigation cited an overheated roller/bearing assembly in a pelletizer as the likely ignition source.

Clearly, the process of manufacturing wood pellets involves all the right ingredients for explosions and fires to occur with a concerning frequency the potential to cause serious injuries, damage to property, and interruption of production.

What are Wood Pellets and Biomass Fuels?

For many years, wood pellets were referred to as, well, “wood pellets”.  Recently, wood pellets are being referred to as one form of a broader category known as biomass fuels. The term biomass refers to materials that have originated from living, or recently living, organisms. Most often, it refers to plant material. Biomass, including wood, can be used directly (through combustion) or indirectly to create heat and electricity. In order to use biomass indirectly to create heat or electricity, it must first be converted into some form of biofuel. There are various types of biomass fuels, or biofuels; however wood pellets are the most common type, and are generally made from compacted sawdust.

Wood pellets and other biofuels are considered to sustainable.  Reportedly, they can help to reduce reliance on fossil fuels, like oil, to produce heat and energy. Because of this, the industry is expected to boom in the upcoming years. As the manufacturing of wood pellets grows to meet demand, it is fair to predict that the number of explosions and fires will increase in direct proportion.

Stay tuned for part two of this series: Fire Prevention Tips for Wood Pellet Plants.

By , CEO and Founder of Harrington Group, Inc.

 

Be Sociable, Share!

Join Our E-Newsletter

If you would like more information, or believe your firm could benefit from Harrington Group’s expertise, we invite you to contact us. Our engineers are trained to listen to your needs and concerns, and help you move forward to find the Best Total Solution.

1 Comment »

  1. I read your overview of the dangers of wood pellet plant facilities. It is a good introduction to the subject. You may be interested in the fact that the use of a wide variety of scrap wood materials is quite common. The problem is that these materials are not always pre-mixed into a multi-particle sized, fairly homogeneous raw material feed stream to the hammermills prior to compression. This mistake can cause problems at the interface of the hammers and screens. A two ton batch of very fine sawdust fed into the mill followed by wood chips or shavings imposes an impossible task on the milling process. The fines plug the screens and cause frictional heating and possible fires if the mesh of the screen is too small. The wood shavings require a different feed rate, rpm of rotor and screen size. Premixing the feed materials allows the designer to establish a range of operating parameters that prevent the frictional heating conditions.

    The second issue is that the basic rule of high risk equipment being aspirated by a dedicated, explosion protected system and low risk equipment by a second dedicated, explosion protected system is not always followed.

    The two incidents HRC investigated used one dust collector with pick-up points at the sawdust dumping station, mill, compactor, conveyor belts and bucket elevators. The flash back from the milling chamber propagated to the dumping station where the operator of the bulldozer was protected from the fireball by the large plow. Similarly, fireballs exited the milling chamber, feed conveyor to the compactor and bucket elevator.

    In closing, these systems are very basic dust handling processes that are not always being properly analyzed for dust explosion hazards.

    Comment by George Petino, Jr. — January 15, 2014 @ 3:13 pm

RSS feed for comments on this post. TrackBack URL

Leave a comment