DE3317404A1 - CARBON DUST BURNER - Google Patents

Description

The invention relates to pulverized coal burners, particularly for hot water or Steam boiler or hot gas generator.

Coal dust burners or dust firing are generally suitable for all types of coal. Dust firings have a thermal output of up to 2,500 MW built! Several individual burners are interconnected in the large units. The output of the individual burners can be up to 70 MW. The lower limit for the use of dust firing is called 1 MW viewed. This limit is essentially due to economic reasons.

The possible uses of the pulverized coal burners range from ceramic ones Industry, the metal industry, via hot gas generators for drying systems, Hot air generators, cement rotary kilns, lime rotary and lime pouring kilns, Gypsum plants to boiler plants. In the case of boiler firing, the use of dust firing has so far been reserved for large power units. The use of ready-to-burn dust is for small power units unusual. One reason for this is the difficulty in dosing. The invention is therefore based on the task of improving the dosage on pulverized coal burners.

According to the invention, this is achieved with a coal dust container which a fluid base, an injector arranged above the fluid base for Has air and a nozzle arranged in the injector air flow. The fluid floor allows different modes of operation. That is, in minimum operation the fluid bottom causes the coal dust in the container to be loosened by air entering. This causes the coal dust to trickle Everywhere, including between the injector and the nozzle, and is entrained into and out of the nozzle by the air stream emerging from the injector fed from the nozzle to the burner. The latter happens, for example, via a line connected to the nozzle in the burner skirt of the pulverized coal burner opens, which surrounds the flame chamber of the burner.

Optionally, the air inlet through the fluid floor can be increased so that that in the area of the injector and the nozzle a fluidized bed with the coal dust particles in the container is created.

An exemplary embodiment of the invention is shown in the drawing. Show it:

Figure 1 is a schematic overall view of the dosing according to the invention. tion for a pulverized coal burner;

FIG. 2 shows a section along the line A-B in FIG.

According to FIG. 1, there is a container 1 with a funnel 2 at the lower end provided, which opens into a cylindrical intermediate piece 3. The cylinder adapter 3 is flanged to the outlet opening of the funnel 2. At the end of the cylindrical intermediate piece facing away from the funnel 2 3, a fluid floor 4 is flanged on. In the exemplary embodiment, the fluid base 4 consists of a spherical cap which is provided with a plurality is provided with evenly distributed small air inlet openings. For this purpose, the fluid floor is designed and located with a double floor inlet openings in the inner floor. The outer floor forms a closed one Outer jacket and is provided with connection openings for connection lines 5. The amount of air supplied through the connecting lines 5 is 0.05-10 m / h. The amount of air depends on the one to be conveyed Amount of coal dust. It must be so large in each case that the container pressure rises and a pressure valve arranged on the container can respond. After the pressure valve responds, air is blown off.

For reproducible values of the amount of dust conveyed, it is advantageous to to fluidize the coal dust always to the same extent. This fluidization takes place between an injector 6 and a nozzle 7. The injector 6 and the nozzle 7 are arranged on the cylindrical intermediate piece 3. The distance between the fluid base, injector and nozzle is preferably 100-200 mm. It should not exceed 500 mm to ensure that the space between the injector and the fluid base is emptied and it is not clogging of the fluid base 4 occurs.

In the exemplary embodiment, an injector and a nozzle are shown in each case. Their number can be four or eight, depending on the requirements

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increase. Ultimately, only the spatial relationships set the top the limits. The injector 6 and nozzle 7 are preferably each separate arranged in an intermediate piece 3, so that the number of injectors and nozzles can be changed as desired by adding or removing spacers 3.

The arrangement varies depending on the geometric configuration of the fluid base of the injector 6 and the nozzle 7. If the fluid base 4 is round, the injector 6 and nozzle 7 sit centrally above the fluid base 4.

In the exemplary embodiment, the injector consists of one fixed in the intermediate piece 3 assembled pipeline with replaceable tip. The passage opening for air in the replaceable injector tip has one Opening width from 5 to 20 mm. Preferably the opening has a diameter from 8 to 10 mm.

The nozzle 7 is provided with a funnel, the opening angle of which is 15 to 90 °, preferably 30 to 45 °. ' ^:

The distance between the injector 6 and the nozzle 7 can be changed. By Change in distance affects the delivery rate of coal dust. That is, if the distance is too great, the delivery can no longer be regulated. In to the funding decreases at a small distance. It becomes zero when the interchangeable Injector head is in the funnel of the nozzle. Optionally, the injector can also be moved or the injector and nozzle become common emotional. For a movable arrangement, the injector 6 and nozzle 7 are smooth and movably mounted in the jacket of the intermediate piece 3.

The opening width of the nozzle is smaller, at most equal to that of the injector 6. With an opening width of 8 to 10 mm in the injector 6 there is one Nozzle bore 3 to 5 mm in diameter provided.

The fluidization of the coal dust in the area of the injector 6 and the Nozzle 7 ensures that the coal dust particles move easily between nozzle 7 and injector 6 and from the injector air stream into the funnel the nozzle 7 and from there into the nozzle 7 itself.

The air flow emerging from the nozzle 7 is conveyed by a pipe .8 led to the burner and opens there into the space surrounding the flame Burner shirt, which is formed, for example, by a ceramic jacket will. ■ '

The entire process is significantly influenced by the tank pressure. Therefore, a pressure control with suitable pressure gauges is provided. In the exemplary embodiment, a manometer switches a solenoid valve z. B. at 1 bar tank pressure. This tank pressure builds up after a while Time when the fluid floor is pressurized with 2 bar air pressure. At the same time there is an injection pressure of. 1.5 bar provided. With this setting ensures that sufficient air can flow into the container. Incoming air fluidizes the coal dust to be discharged.

When so much pressure has built up in the container that the switching point the pressure gauge is reached, the pressure gauge actuates a solenoid valve. Air is released from the container via the solenoid valve. The pressure control and the air outlet are denoted by 9 in FIG. After the pressure has dropped to 0.05 bar, the solenoid valve is closed again and the fluidization process continues with a renewed increase in pressure in the container.

The above pressure setting is particularly suitable for short conveying distances from the nozzle 7 suitable for the burner shirt, not shown. The pressure is influenced on the length of the conveying path and the cross-section of the conveying line. Injection pressures change with increasing length of the conveying path and flow pressure at the fluid floor. Further, the pressure at which the solenoid valve is operated to blow air is increased.

If the conveying path is longer, for example 20 to 30 m, there is a. Pressure of 4 bar at the fluid base, while the injector pressure is 3.5 bar. The associated switching point of the pressure gauge is 3 bar. The operating pressure of the container 1 depends on the length of the conveying path between 0.5 and 4 bar. Without further ado, however, excessively long conveying paths can be achieved by correspondingly higher pressures of z. B. 8 bar taken into account.

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Claims (10)

Γ T.i / pulverized coal burners, especially for hot water eggs or steam boilers or hot gas generator with a coal dust metering, characterized in that the metering from a coal dust container (1) with Fluid base (4), an injector arranged above the fluid base (4) (6) and a nozzle (7) arranged in the injector air flow. 2. pulverized coal burner according to claim 1, characterized in that the flui
amounts to. 3 the amount of air supplied to the fluid floor (4) between 0.05 and 10 m / hour. 3. pulverized coal burner according to claim 1 or 2, characterized in that that the distance between the fluid base (4) on the one hand and the injector (6) and the nozzle (7) on the other hand between 50 and 500 mm, preferably 100-200 mm. -. 4. pulverized coal burner according to one or more of claims 1 to 3 ,. characterized in that the nozzle (7) is provided with a funnel is, the opening angle of which is 50-90 °, preferably 30-45 °. 5. pulverized coal burner according to one or more of claims 1-4, characterized characterized in that the air passage opening in the injector (6) has an opening width of 5-20 mm, preferably 8-10 mm. 6. pulverized coal burner according to one or more of claims 1-5, characterized in that the distance between the nozzle (7) and injector 3-6 mm. 7. pulverized coal burner according to one or more of claims 1-6, characterized characterized in that the opening width of the nozzle (7) is less than or equal to that of the injector (.6). 8. pulverized coal burner according to claim 7, characterized in that the Nozzle with an opening width of 8-10 mm in the injector has an opening width of 3-5 mm. 9. pulverized coal burner according to one or more of claims 1-8, characterized marked that the container (1) is provided with a pressure limiter (9) * 10. pulverized coal burner according to claim 9, characterized in that the Tank pressure is 0.5-4 bar.