Customised fire protection solutions for the pellet production
GreCon fire extinguishing systems ensure the production availability of KWatt Bois, a manufacturer of pellets based in the Pyrenees
The French company KWatt Bois protects its entire pellet production line using GreCon spark extinguishing systems. Production stages as drying, pressing and
storage which are subject to a fire hazard are preventively protected by an individual fire protection solution.
At the foothills of the Pyrenees in the department Ariege, KWatt Bois produces high quality pellets under the brand name "Pepites". These wood pellets are not
only famous in the region but throughout the nation. Directly besides the pellet factory the corporate sawmill and the combined heat and power plant are located.
"The immediate vicinity of these three companies makes an optimisation of our maintenance and the maximum reduction of transport distances possible",
Jean Bouichou, Technical Director of the pellet production lines of KWatt Bois emphasises.
"The sawmill provides for the supply of the wood on the one hand and on the other hand, we receive the heat energy necessary for the production of the
pellets from the combined heat and power plant. We are able to control the complete delivery chain of the Pepites pellets and produce a unique reliable fuel.
Caption 1: Synergies are used – A sawmill and a combined heat and power plant are located in immediate vicinity of the pellet producer.
A constant and homogenous quality is guaranteed
In the sawmill, the trunks are first peeled, cut and sorted according to their purpose.
The produced waste, as peeled off bark or wood of a lower quality, is the raw material for the pellet production.
The production of high-quality pellets can be divided into five production stages: shredding, drying, pressing, refinement/screening and packaging.
"The shredding and drying stages are absolutely necessary for the production of pellets of best quality", Jean Bouichou explains.
"The residual wood, the saw dust and the chips are cautiously shredded in the refinement stage and screened. We are able to produce homogenous pellets in a constant quality
ensuring a calorific value of the pellets of more than 5,000 kWh."
Afterwards the material is processed to pellets in the press. "In contrast to other companies our production is without additives: our pellets are 100% natural",
the Technical Director of the pellet production systems underlines. "The pellets then pass a fine screen to ensure quality. The ash rate is reduced below 0.7% with a
humidity rate of 10%. If the products do not meet the required criteria, they are recycled in the internal boiler. If the quality criteria are met, packaging takes place.
" The company uses two types of packaging: 15 kg bags and storage in silos for bulk delivery.
Caption 2: Pépites – Pellets from the Pyrenees, famous throughout the country.
Fire hazard in several production stages
The risk factors are numerous and manifold. If the material stays in the dryer for a long time, a spontaneous ignition of the material may result. Foreign bodies as stones or metal parts
represent another danger. If they reach the production machine, sparks are inevitably generated which may cause an explosive atmosphere (e.g. filter or silo systems)
when they enter dangerous areas through mechanical or pneumatic transport.
"The production of wood pellets is a complex procedure. Nearly all process stages may be subject to fire. Production tools can be destroyed - and in more serious
cases even all facilities", Yannik Provo, sales engineer of Fagus-GreCon, underlines.
According to Provo, eleven process areas were determined together with the customer that represent an increased fire hazard. "These areas extend from the belt dryer,
the storage silos via the material chutes at the outlet of the dryer, the cooler, and the exhaust systems up to the outfeed of the press."
Extinguishing before a fire breaks out!
To minimise the risks of a fire in the pellet production, the French pellet producer started to protect hazardous areas with GreCon spark extinguishing systems.
Sparks and hot particles are rendered harmless before they can cause damage in a downstream system.
The fire extinguishing system mainly consists of three elements: the spark detection station, the spark detectors and the automatic extinguishing system.
The centre of the spark extinguishing system is the spark detection station. All signals from the individual spark detectors in different areas of the system come in
here and are evaluated. The connected extinguishing units of the corresponding areas are activated within milliseconds.
With more than 100,000 installed spark extinguishing systems, Fagus-GreCon has been demonstrating its competence and experience in the preventive fire protection
for more than 40 years.
Caption 3: Sparks and hot particles are detected by highly sensitive infrared detectors and extinguished by a fine-atomised water fog before damage is caused.
After detailed analysis, the French company decided to use a control centre of the new generation "GreCon CC 7016 Touch". As heart of the protection system, it administers
automatically the peripheral equipment to detect and extinguish sparks.
Caption 4: The GreCon flame detectors monitor the interior of the dryer for potential fire hazards.
Caption 5: The highly sensitive GreCon spark detector FM 1/8 at the exhaust of the pellet cooler
Two years after commissioning of these protection systems, KWatt Bois seems to be completely satisfied: "We are considering the installation of a second press",
Jean Bouichou adds. "The new press would double our production capacity. If we decide to do so, there is no doubt that Fagus-GreCon will be our preferred partner
for this new system.