Explosion Prevention in the Biomass Industry

Biomass safety is more important that ever before. Biomass energy is now becoming the biggest growth in Green field installations, as countries come to terms with their waste problems. Processes handling a combination of Dust, Gas and Vapour hazards are beginning to be developed, requiring the full range of Explosion prevention and protection systems available.

Renewable energies witnessed a 19 percent growth in 2011, making it the ninth year of double digit growths for renewable.

What implications does this have for biomass safety? If you look at the news section of our website, explosions are being reported every month from Wood processing facilities, Bio diesel plant, Sewage treatment, Grain Silos, Coal fired plants, saw dust mills (with pine beetle killed wood coming in dryer), even the pellet drying plants are seeing incidents.

Key Solutions for Biomass Safety

Isolation by dry chemical powder isolation

One of the most integral elements to biomass safety is isolation. It’s absolutely imperative you have the right explosion isolation equipment in place.

ATEX Dry Chemical or Hot Water Isolation Systems provide an effective means of isolating the flame front growth of an advancing deflagration. With the same features as an ATEX Suppression system they suppress the advancing flame front and mitigate the advancing pressure wave.

When the Isolation device receives a ‘fired’ signal from a control system and/or sensor it fires the gas generators, releasing the valve. Extinguishing chemical is then discharged under 60bar pressure into the protected plant. Having such measures in place is key to biomass safety

This is the first system to address the high cost and supervision requirements of traditional systems. Compared to previous systems which employ complex monitoring and actuation devices, the ATEX Powder Isolation system comprises simply a valve and two gas generators. This makes for high reliability and low maintenance biomass safety equipment. The dual gas generator valve actuator provides redundancy for added safety. Another major benefit, on-site refurbishment dramatically reduces downtime after a device(s) discharge.

Flameless Venting

The ATEX Flameless Explosion Vent is a safe indoor venting solution for explosion protection of indoor processes in personnel areas and again is an integral element for biomass safety. It uses a stainless steel mesh filter to quench vented explosions and arrest flames.

The ATEX Flameless Vent System was developed in response to a specific need, i.e. explosion venting inside buildings. Traditional explosion venting technologies require a safe venting area (usually outdoors), where there is no risk of secondary explosions or harm to personnel. Explosion vented plant has to be ducted out to a designated (external) safe area (usually within 3 to 6 metres). The only alternative was to strengthen vessels to withstand greater explosion pressures and/or to install relatively expensive explosion suppression systems.

The ATEX Flameless design allows venting of explosions without the attendant risks of an external fireball and without the use of vent ducts. It is essentially a flame-arrester comprising a porous, heat-absorbing surface in the form of a cage. The vented explosion enters the cage, the gases are cooled as they pass through the porous surface, dust is filtered out and the flame is quenched. The internal surface-area of the ATEX Flameless vent is designed so that the effective vent area is almost the same as if the vent itself was free.

Recent Explosions

Nothing highlights the importance of proper biomass safety more than the many (Often tragic) incidences that take place every year. Biomass safety is not about protecting your equipment –  it’s about protecting lives.

Egger Hexham chipboard plant in June 2013.  Their wood burning biomass incinerator caught fire.

Buena Vista Biomass power plant, California in May 2013.  Two people injured one seriously, catastrophic mechanical failure.

Koda Energy CHP plant Minnesota exploded April 2013 igniting a fire in 2 of its fuel storage silos that burned for a week.

Biomass One Incinerator in Oregon, burst into flames September 15th and 18th in 2012. This is supposed to be caused by Spontaneous combustion in the woodchip pile.

Dong Energy biomass incinerator in Copenhagen experienced a fire in August 2012 that began in its electrical conveyer system and spread on to its wood pellet silos.

Amager Power station in Copenhagen burns biomass and coal. In May 2012 three people injured from wood dust explosion caused by a cleaning process called “bang and clean” using small explosions of oxygen and methane to clean boiler but this time used to unblock a plug of wood pellets.  Fire returned to the facility also in December 2012.

Avedore Conveyor roller ignites dust to silo. Fire-fighters, Tilbury a technically challenging fire. Again showing just how important biomass safety is.

Rwe’s Tilbury Power station in Essex had a biomass fire in February 2012 in its converted coal silos probably from smouldering wood pellets on an external source above the silo.

On Monday 27 February 2012 at approximately 07.25 hrs a fire broke out in the bunker house for Units 9 and 10 at Tilbury Power Station. The fire was brought under control by 14.48 hrs but smouldering of remaining fuel in the bunkers continued for a number of days. The fire developed from smouldering wood pellets in one of the bunkers, that had been initiated by hot dust and embers falling into the bunker. (Saturday 25 February at around 12.15 hrs) The smouldering had been detected and controlled immediately by capping the affected area with high expansion fire suppressant foam. Further applications of foam and increased monitoring of the area continued throughout the weekend.  The plant was out of service during that time and no material was added to or removed from the smouldering bunker.

A huge fire ripped through the wood pellet storage facility in the Port of Tyne in October 2011. It is thought to be from spontaneous combustion inside the silo.

Three workers killed in the Brilon Chipboard plant in Germany in February 2010 cause unknown.

The most recent tragic event at Wood Flour Mills in Bosley Cheshire July 2015 where the site was also struck by fires in 2010 and 2012. Wood is processed at the plant into a fine powder and the resulting “wood flour”, with a consistency like sand, is used to make laminate flooring. Days later search teams have not found all the bodies under the rubble.

Explosion Hazards offers the very best in biomass safety solutions. If you’re unsure what biomass safety measures you should implement into your operation, contact us today and we’ll find a solution that meets all of your specific requirements.

We can use nearly 50 years of experience to make you a safe ATEX compliant company