DE2930258A1 - COMBUSTION METHOD FOR MOISTURE Bark - Google Patents

Description

1 July 24, 1979

D / Su

DipUng.W.Dahlke

Dipl.-Ing. H.-]. Lippert

Patent attorneys
Frankenfotster Strasse 137
5060 Bergisch Gladbach 3

POHJAN SAHA OY JäminkipohYes, Finland

"Combustion method for moist tree bark"

This invention relates to a method of burning wetter Tree bark especially without the use of additional thermal energy in smaller systems.

In large-scale industry, tree bark and wood waste are produced in Kesselj systems with combined firing burned, with temperatures so high that the moisture in the furnace evaporates and the

I said waste wood and debarking in this way Extraction of the thermal energy contained in them can be eliminated. However, this conception is insignificant because of its Efficiency and the high price of combi-firing boiler systems not suitable for smaller businesses. For this reason, a single-stage, pure wood and bark firing should be aimed for, as can be found today in several hundred companies in the Nordic countries. These are already in operation However, systems make too high demands with regard to the moisture content of the bark and wood waste. The previous

030010/0654

Experience has shown that with the previous devices only bark is sufficiently good and with sufficient; Can burn power, the humidity of which is not more than 60 %, based on the total mass. For bark with more than 60 % moisture, however, an additional oil furnace is still required; necessary.

The combustion method according to the invention provides the aforementioned Deficiency eliminated. The main features of the invention go out

Claim 1 emerges. ;

Tests carried out have shown that superheated flue gas vapor does not reach its dew point until around 70 ^° C., which is probably due to the flow velocity.

The basic idea of our invention is therefore to use the thermal energy of the flue gas for drying to such an extent that the dew point is only reached outside the actual drying drum or the like when the bark is indirectly heated, whereby the moisture contained in the flue gases does not change with the drying bark comes into contact. The remaining energy is passed under the bark silo, for example, whereby the preheating of the bark with the remaining, low temperature level - below 100 ⁰ C - is also used and the condensation of the flue gas moisture takes place at the same time in the same room, so that their Heat of evaporation is used.

030010/0654

The operational sequence according to the method according to the invention designed system is, for example, the following:

Moist wood waste and / or bark containing more than 60 % water are transported from the storage silo with a screw conveyor into a rotating drum dryer and from the other end of the same with a screw conveyor into the furnace of the boiler system. The arising there in the combustion flue gases are countercurrently supplied to the waste wood and / or bark in the drum dryer, which visited a F _e of are less than 40%, preferably dried below 30% before it enters the combustion chamber. The flue gases are discharged from the drying drum before reaching their dew point, that is to say at a temperature of about 100 ^{° C. and under the!} The bottom of the storage silo passed through into the chimney.

The moisture contained in the flue gases condenses and transfers its thermal energy to that of the drying drum at the bottom of the silo debarking and / or wood waste to be supplied with simultaneous preheating of the same.

When working according to the method described above, excellent results were achieved even with a moisture content of over 65% , thus saving import energy sources such as oil.

The invention is not limited to the example given above; so the debarking and wood waste warehouse does not need

of a silo and the actual dryer not to be formed by a drum dryer.

030010/065 *

Claims (2)

July 24, 1979 D / Su Dipl.-Ing. W. Dahllce
Dipl.-Ing. H.-J. Lippert Pu (ent απ w oiled
Frankenforster Strasse 137
5060 Bergisch Giadbadi 3 POHJAN SAHA OY
Jäminkipohja, Finland Claims η 7) Process for burning moist tree bark and / or wood waste, in which the wood waste and / or bark ; goods coming from the store in the countercurrent process with from the furnace, where this good is burned, outgoing smoke is dried, thereby marked that the flue gases, before reaching their dew point, the indirect preheating of the actual direct Wood and / or debarking waste to be supplied for drying are supplied. 2. Method according to claim 1, characterized shows that the flue gases leaving the drying drum at a temperature of about 100 ^° C. are passed under the floor of the wood and / or debarking waste silo before they are introduced into the chimney. 030010 ^ 0654