Combustion trials

Optimization of the combustion settings to the biofuels

Mixed biofuels and traditional wood pellets don’t have the same physical and chemical characteristics, which can have consequences when burning:

• More ashes production and slag formation due to a higher silica content and a lower melting ash temperature
• Corrosion of boilers and acid emissions due to chlorine, nitrogen or sulphur in larger proportion.

Carrying out tests of performance on biofuel pellets will allow us to select the most appropriate biofuels to benchmark different recent technical possibilities of improvement and then find the best fittings between type of pellets & combustion settings.

Biofuels preparation

For combustion experiments, different kind of biofuels are produced:

• Bulk or baled grasses for industrial units;
• Biofuels pellets for individual and collective boilers: energy crop (i.e. hemp, see energy cereals), or crop residues (straw, vineyard shoots…)

Physical and chemical composition of the biofuels are characterised so that we can explain their energy characteristics and environmental impact in terms of gas emission and ash content.

Checking combustion performances in pilot lab conditions

First, herbaceous biofuels are tested in lab conditions to check combustion conditions and atmospheric emissions. Then we select the most competitive pellets which will be tested in real conditions.

Each biofuel is tested for 2 days, according to a recommended protocol, and compared to wood pellets combustion.

The following parameters are monitored:

• Combustion and boiler yields
• Emissions atmospheric of CO, NOx, SO2, VOC, HAP, Dust

One trials campaign is planned in 2010 and another one in 2011
 

Description du protocole d’essai en laboratoire

Checking combustion performances in real conditions

Then, combustion conditions and atmospheric emissions of biofuels are checked on individual, collective and industrial multi-fuel boilers, in real conditions.

10 owners of multi-fuel boilers spread on the territory of the project have been selected : 1 for industrial application, 2 for collective application and 7 for domestic heating.

On each site, one type of biofuel is tested for a month and compared to conventional wood fuel (wood chips and wood pellet). Same parameters than in lab tests are monitored.

The aim of these tests is to supply recommendation for the adequacy between boiler technology, tuning boilers and main physical and chemical characteristics of mixed herbaceous pellets.
Pilot sites presentation Téléchargez

Description du protocole d’essai de combustion en sites pilotes
Présentation des sites pilotes (FR)
Synthesis of the first measurement campaign (FR)

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