Viadrus HERCULES E68 5 A, Руководство по эксплуатации и установке, Страница: 23 / 40

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It is necessary to observe maximum wood humidity of 16-18 %. The higher wood humidity, the lower boiler power. During combustion
of wet wood, water is separated and condensed on walls of the proper boiler drum and chimney body; it causes increased creation of
tar and water steam, which decreases the service life. Insufficient combustion also causes corrosion of cast iron, so called "metal
dusting", when carbon is diffused into material, and - by this - material decomposes to powder (dust). This process is gradual and
long-term. The flow of flue gases with solid particles then causes wearing or erosion of the material from the surface, and by this the
thickness of the section wall gradually attenuates, and this can cause perforation of the boiler drum.
Fuel has to be stored in dry place.
Influence of wood humidity on the calorific value and specific weight
Fuel type
Water
content
Calorific value Volume weight
[%] [MJ/kg] [kg/prm]
Broad-leaved wood (Beech) 15 14.605 475
Broad-leaved wood (Beech) 50 7.585 791
Needle-leaved wood (Pine) 15 15.584 340
Needle-leaved wood (Pine) 50 8.161 567
[prm], [rm] = 1 m
3
of stacked logs, contents 60-75% of wood (stacked cubic meter)
The tabulated values are drawn from the Internet-portal of TZB-info.
Reference example of calorific value of a fully-loaded boiler
Water
content
Weight of
fuel in the
loading
chamber of
the boiler
type 16
beech wood*
Theoretically
usable
thermal
energy of the
boiler
type 16
beech wood*
Weight of
fuel in the
loading
chamber of
the boiler
type 16
pine-wood
Theoretically
usable
thermal
energy of the
boiler
type 16
pine-wood
[%] [kg] [MJ] [kg] [MJ]
15 13 169 9.3 129
50 21.6 88 15.5 68
* Fuel used upon certification of the boiler.
Do not use for combustion: plastics, domestic waste, chemically treated remnants of wood, old paper, wood chips, pilers, waste from
boards pressed from bark or from chipboards.
▶
Follow instructions for boiler operation.
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While operating the boiler, follow recommended operational temperature.
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Operated the boiler with the approved fuel.
Dry wood
Humidity lower than 18%
High calorific
value
Semi-dry wood
Humidity between 18% and
25%
Middle calorific
value
Wet wood
Humidity more than 25%
Low calorific
value