Viessmann KOB PYROTEC, Technical Manual

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1.1 Principles of pellet combustion for generating heat
What are wood pellets?
Wood pellets are made from 100% natural wood residues. This raw material is waste matter created by the wood industry in large volumes
through planing or sawing. Wood remnants are compressed under high pressure and formed into pellets, i.e. pressed into a cylindrical shape.
The raw material is stored and transported in completely dry conditions. The system user should also ensure completely dry storage conditions.
Perfect and effective combustion can only be ensured under these conditions.
Fuel requirements
For combustion in the PYROTEC, use pellets with a diameter of 6 mm,
a length from 5 to 30 mm (20 % up to 45 mm) with a maximum residual
moisture content of 10 %.
The wood pellets used for combustion in the PYROTEC must comply
with the requirements of DIN
plus or ÖNORM M 7135.
Demand DINplus Ö-NORM
M 7135
Abrasion resistance %
≤ 2.3 ≤ 2.3
Raw density kg/dm 3
≥ 1.12 ≥ 1.12
Water content %
≤ 10 ≤ 10
Ash content %
≤ 0.5 ≤ 0.5
Net calorific value MJ/kg
≥ 18 ≥ 18
kWh/kg
≥ 5 ≥ 5
Sulphur content %
≤ 0.04 ≤ 0.04
Chlorine content %
≤ 0.02 ≤ 0.02
Nitrogen content %
≤ 0.3 ≤ 0.3
Compression additive %
≤ 2 ≤ 2
Ext. production control yes –
Quality characteristics
High quality pellets:
■ smooth shiny surface
■ uniform length
■ low proportion of dust
■ sink in water
Low quality pellets:
■ cracked rough surface
■ severely varying length
■ high proportion of dust
■ float in water
Forms of delivery
In their loose form, pellets are transported by silo tanker and blown into
the storage room via a hose system. Careful handling of pellets enables a low proportion of dust, perfect
boiler charging and a constant wood boiler output.
1.2 Principles of woodchip combustion for generating heat
What are woodchips?
Woodchips are made from 100% natural wood from forests and plan-
tations. This raw material comes in the form of trunks or branches. The
wood is then processed with high speed cutting tools in accordance
with ÖNORM M 7133. The raw material is stored and transported in completely dry condi-
tions. The system user should also ensure completely dry storage
conditions. Perfect and effective combustion can only be ensured
under these conditions.
Fuel requirements
For combustion in the PYROTEC, use woodchips with a maximum
percentage of coarse chippings of 20%, a maximum cross-section of
5 cm² and a maximum length of 12 cm (5 % with max. 16 cm). The
water content of the woodchips may be max. 50 % (W50).
Bulk density S (kg/m³, water content W (%), size G (mm) as per ÖNORM M 7133
S 200
W20 G30/50 Soft natural woodchips from forest thinnings
S 250 W20 to W35 G30/50 Soft natural woodchips from forest thinnings
S 300 W20 to W35 G30/50 Soft/hard natural woodchips from forest thinnings
S 300 W35 to W50 G30/50 Soft natural woodchips from forest thinnings
S 350 W20 to W35 G30/50 Hard natural woodchips from forest thinnings
S 350 W35 to W50 G30/50 Soft/hard natural woodchips from forest thinnings
S 350 W50 to W60 G30/50 Soft natural woodchips from forest thinnings
S 400 W35 to W50 G30/50 Hard natural woodchips from forest thinnings
S 400 W50 to W60 G30/50 Soft/hard natural woodchips from forest thinnings
Quality characteristics
Good woodchips:
■ As per ÖNORM M 7133
■ Size up to G30 or G50
■ Max. 5 % outliers
■ Smooth surfaces
Principles of wood combustion
PYROTEC
5
5822 511 GB
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