DE3124908A1 - "ARRANGEMENT FOR DRAINING AND COOLING ASCCHE FROM A FLUID BED COMBUSTION CHAMBER" - Google Patents

Description

Arrangement for draining and cooling ash from one Fluidized bed combustion chamber

The invention relates to an arrangement for draining and cooling ash from a fluidized bed combustion chamber.

A lot of ash is constantly forming in a fluidized bed combustion chamber, on the one hand from the fuel and on the other hand in Form of used or worn bed material that is used for desulfurization. Except the need for this To get rid of ashes is. it is important to use their heat content, in order to achieve a good economy of the combustion chamber. At the same time you get that the remaining coal is finally burned.

The invention is based on the object of developing an arrangement of the type mentioned above, with which the removal der.assche and the utilization of their heat content in a simple and in an economical manner.

To solve this problem, an arrangement according to the preamble of claim 1 proposed that, according to the invention, the features mentioned in the characterizing part of claim 1

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An advantageous further development of the invention is in the dependent claim called.

In the arrangement according to the invention, cooling air is blown upwards through the discharged ash. It is important to that the speed of the cooling air is so low that the ash is not fluidized in the shaft. This avoids mixing of cold and warm ashes in the shaft, so that a uniform temperature drop is obtained throughout the ash layer.

Based on the embodiment shown schematically in the figure

game of an arrangement according to the invention, this will be explained in more detail.

The figure shows a fluidized bed combustion chamber, the outer jacket is denoted by 1 and which has an air chamber 2 at the bottom. Air is blown in via a duct 3, which passes through the perforated Floor 4 flows up into the bed mass into which Fuel is blown in. For this purpose a large number of fuel nozzles are usually provided in the bottom 4, which are not shown in the figure.

Discharge shafts for ash are arranged at suitable points in the bottom of the combustion chamber, the upper section of which is made from a relatively narrow ash tube 6, which is attached to the bottom 4

- 4 is connected. The tube 6 opens into a further section

7 of the shaft, where the ashes spread over a double floor 8,9. Cooling air is passed through the pipe 10 between the floors

8 and 9 and passed through holes in the upper floor 9 upwards. Because the shaft section 7 is wide, large. Amounts of cooling air are passed through the ash in a countercurrent, without it being fluidized. The heat exchange in This countercurrent heats the air on its way through the ashes, and by choosing the appropriate amount of air, one can use the Maintain the upper area of the ash located in the shaft section 7 at such a temperature that coal residues are burnt can take place in the upper area of the ash column. A certain proportion of the cooling air passes through the pipe 6. The ashes in the pipe 6 has such a high temperature that the remaining coal is burned to the extent that the oxygen content of the after allows air flowing above. Only a limited part of the remaining coal in the ashes has to be burned in shaft section 7 in which one has a safe excess of oxygen.

The used 'cooling air is through a special pipe 11 directly up into the combustion chamber, where it is used as heated secondary air. This only gives you a very limited upward flow of air in the ash tube 6 so that the ashes can smoothly slide down through this pipe.

Bushings 12 are arranged between the floors 8 and 9, through which the ashes after cooling down in the funnel-shaped

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gen part 13 of the shaft passed down. The ash is then passed down through the pipe 14 into an ash conveyor 15 in a known manner.

As can be seen from what has been said, the inventive idea can be used both in overpressure combustion chambers and in combustion chambers that operate at atmospheric pressure. This is just a question of the choice of air pressure for the cooling air and the dimensions of the walls and other parts of the shaft.

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Claims (2)

"Protection claims: /1.J Arrangement for draining and cooling ash from a Fluidized bed combustion chamber, characterized in that a drain shaft (6) is arranged at the bottom (4) of the combustion chamber is, which opens into an ash chamber (7) with a discharge arrangement (1-3-15) on the floor and with arrangements (.8, 9) for blowing cooling air into the ashes under the Mouth of the drain shaft (6) is provided, and that between the ash chamber (7) and the combustion chamber a pipe connection (11) for conducting cooling air into the combustion chamber is available. 2. Arrangement according to claim 1, characterized in that the lower part of the ash chamber (7) under the injection arrangement for cooling air merges into a funnel-shaped part (I3), whose lowest point is connected to an ash conveyor (14, 15).