Minimum Wood Fuel Requirements; Content; Non-Wood Biomass Fuels - Viessmann VIESMANN VITOLIGNO 300-H Technical Manual

Principles of wood combustion

1.4 Minimum wood fuel requirements

Content

When buying wood for combustion, it is important to ensure that foreign
matter (e.g. stones, metal parts, brick fragments, plastics, etc.) is avoi-
ded. This would change the composition of the fuel and therefore the
critical parameters of the combustion process. All wood-based fuel
must be free from foreign bodies such as metal particles, stones,
masonry remnants or plastics.
Chlorine Cl
Sulphur S
Total Cl, S
Ash content total
Alkali oxides in the ash (K O and Na
2
SB start of ash sintering
Exceeding the above limits will shorten the service life of the combus-
tion chamber and the solid fuel boiler. This also means that the amount
of maintenance work increases and shorter service intervals.
The proportion of dust-like and fine-grained materials should also be
minimised (in accordance with ÖNORM M 7133).

Non-wood biomass fuels

Non-wood fuels made from biomass such as needles, leaves, cereals,
straw, husks, fruit stones, etc. as a fuel are generally unsuitable for a
fault-free operation, and are therefore not permissible.
VITOLIGNO 300-H
(cont.)
mg/kg
mg/kg
mg/kg
g/kg
O) g/kg
2
°C
The values must not exceed or fall below the following limits (per kg of
dry fuel) for the non-combustible content (ash at an analysis temper-
ature of 815 °C):
Limit Comparison with natural wood from forests
Max. 300
Max. 1000
Max. 1000
Max. 15.0
Max. 1.0
min. 1000
Max. percentage of finest woodchips, dust (wood particles < 1.0 mm
as per ÖNORM M 7133): 10.0 % of total mass
In some cases, the fuel properties (elemental composition, ash sinter-
ing point, etc.) differ considerably from those of wood. Combustion in
a solid fuel boiler can lead to impairment of the combustion charac-
teristics and greater stress on the fireclay lining and heat exchanger
surfaces. Warranty claims can therefore only be asserted when using
approved fuels.
1
10
120
130
5.0
0.35
approx. 1200
VIESMANN
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