CS810188A3 - Combustion chamber for atmospheric stationary fluidized bed combustion - Google Patents

Description

8Ί01 - 8g «>

BACKGROUND OF THE INVENTION The present invention relates to a combustion chamber for atmospheric stationary fluidized bed combustion.

Known technical concepts of stationary atmospheric fluidized bed combustion excel by inexpensive desulphurisation of flue gases by adding basic sorbents to the fluidized bed material. However, the far-reaching problem of NOx is not solved in the known fluidized bed combustion

According to German patent application P 36 23 177.0, known methods for reducing the emission of nitric oxide, such as combustion air grading, have been effectively combined with one another to effect fluids and internal drift circulation, so that all reactive for low-emission combustion can occur in the fluidized bed. .

The atmospheric fluidized bed according to the patent application P 36 23 177.0 has a water-cooled nozzle bottom 3 under the cylindrical water jacket. The hot gas to heat the fluidized bed material to the ignition temperature of the fuel, eventually the primary air, reaches through the primary air box arranged directly below the bottom of the nozzles cooled by the water of the forked forked air nozzles.

The air for the stepped inlet is fed in a controlled manner through a housing arranged below the housing of the primary air fork of the branched air nozzles. The air nozzles are adjustable in height by means of an adjusting device.

The fuel is divided, for example, by a sorting screen device into a coarse and fine fraction. The coarser portion is supplied to the fluidized bed from above, while the fine-grained fuel is introduced into the plane of the plane between the primary air nozzles and the air jets. The coarse particles thus remain in the fluidized bed for a very long time. When dropped, the particles are gassed and burned to a fine grain size. Then the particles remain in the bed and do not fall through it.

The possibility of height adjustment of the graduated air inlet nozzles and the conical widening of the fluidized bed cross section, for example by removing the lining thickness upwardly into the graduated air supply nozzle plane 4, can optimize the air inlet graduation and fluidized bed fluidization according to the type of fuel being fed into the combustion slowing industry. with the effect of reducing the formation of nitric oxide. The conical extension has a diversion from the vertical 30 '.

Submerged heating surfaces extend into the expanded fluidized bed. These heating surfaces start at the end of the expansion and are arranged so that, with a slight change in the height of the fluidized bed layer, the power of the heat generator is changed to a limited extent, with the height adjustment of the scales for a graded air supply.

The fluidized-bed material is separated from the flue gas stream in an unobstructed 1.3 m free space up to a certain size, and through the injector nozzle it reaches over the chute and the filling opening and into the area between the primary air nozzles and the nozzles. a stepped air supply to the fluidized bed. They enter the upper free space, then pass through the separator, out of the combustion chamber and can be cooled, for example, in the downstream heating surfaces.

In order to allow undisturbed discharge of the ash from the fluidized bed, the bottom with the nozzles is conical at a certain 5 angle from 15 to 45 *, here 30 * to the horizontal plane. The air inlet nozzles are forked, so that a uniformly tight spacing, for example 100 nozzle outlet apertures per square meter, does not interfere with conveying the ash to its discharge opening arranged concentrically below the nozzle bottom.

In the old version, the nozzles have 6 holes with a diameter of 4 mm, each branch has 4 branches. From the number of nozzle exit openings per square meter and the number of openings of each branch, the number of branches is 1m2. The number of branches and the number of branches in the branch indicates the number of branches. SUMMARY OF THE INVENTION It is an object of the invention to further improve the known solution of the patent application P 36 23 177.0.

These requirements are fulfilled by the combustion chamber for atmospheric stationary combustion in a fluidized bed with a stepped air supply according to the invention, the principle that a ring for graduated air inlet and / or into the fluidized bed, or are returned to the wall of the immersion heater chamber, by slipping 5 to 8 * to the horizontal plane and / or to extend the fluidized bed in the region of the immersion heater tubes 6 between the lining lying thereon and a circular gap formed above it .

According to a preferred embodiment of the invention, the nozzle orifices of the graduated air supply ring are directed downwards at an angle of 30 to 50 degrees to the horizontal plane.

The immersion heater tubes are preferably guided in the fluidized bed area back to the inner wall of the chamber with the same inclination with which they are introduced into the fluidized bed.

An example of an embodiment of a combustion chamber according to the invention is shown in the attached drawing.

The fluidized bed shown in the drawing differs from the above-described known fluidized bed in that a ring 15 is provided in the upper region of the fluidized fluidized bed for a graduated air supply. Ring 16 is height adjustable. The ring 15 is further divided into a plurality of chambers. Each air chamber is provided with its own air supply pipe 17. An air dispensing valve 18 is arranged in each supply line 17. Furthermore, the fluidized bed apparatus according to the invention differs from the known fluidized bed apparatus 7 as described above in that it has a single place for fuel-to-coal supply in a plurality of different supply points and in that it only has bottom nozzles for supplying air instead of lower ones. and hornítrysek.

In addition, in the illustrated embodiment, the immersion heating tubes have an exit angle of about 7 * to the horizontal plane. The inclination angle may be between 5 and 8.

The submersible heating surfaces in the fluidized bed region back to the inner wall of the chamber at the same angle of inclination. On the submersible heating surfaces, a conduit or holder 16 for the height-adjustable ring 15 is provided for a stepped air supply.

The nozzles 3 have apertures of 3 to 4 mm in diameter and are directed downward at an angle of 30 to 50 °.

By combining the above-described features, in particular by the height adjustment of the ring 15 for the graduated air supply, a partial injection of the carbon monoxide combustion air which is boosted by the fuel supply is made possible.

Finally, the expansion of the fluidized bed is effected in that the lining is disturbed in the region of the immersion heating surfaces. There, the bedding material is stored, which creates a great transition from a thick lining to a thin lining. This results in a circular gap between the lower lining and the upper lining.

Claims (3)

PATENT CLAIMS A fluidized bed combustion chamber for atmospheric stationary combustion with a graded combustion air supply, with a coarse fraction of a fluidized bed fuel and with an internal recirculation of a portion of solid particles emerging from the fluidized bed into a fluidized bed, wherein the air nozzles are arranged in a height adjustable and horizontal plane in the fluidized bed region cross-section extends upwards, according to the patent. (patent application P 36 23 177.0), characterized in that a ring (15) for the stepped air supply is positioned in the upper fluidized bed fluidized area and / or intervened in the fluidized bed or is led back to the chamber wall a submerged heating tube (8) with an inclination of 5 to 8 * to the horizontal plane and / or an expansion of the fluidized bed in the region of the heating tubes (8) between the lining and the lining above is formed by a circular diameter. ! 10 2. The combustion chamber according to claim 1, wherein the nozzle orifices of the ring (15) for the air inlet are directed downwardly at an angle of 30 to 50 degrees to the horizontal plane. 3. The combustion chamber of claim 1, wherein said immersion heating tubes (8) are guided in the fluidized bed region back to the inner wall of the same inclined chamber to be introduced into said fluidized bed.