DE29825240U1 - Wet pocket system used in steam generator, has wet pocket formed with rising portion for mechanically discharging fine-grain and unmelted ash, and feeding unit for transferring and transporting water and ash for subsequent treatment - Google Patents

Abstract

The system includes a wet pocket (2) filled with water for cooling the coal in the coal dust firing of a steam generator which produces and discharges ash after the coal dust firing. A surge water portion drains the ash resulting from the coal dust firing. The wet pocket has a rising portion for mechanically discharging fine-grain and unmelted ash with the water from the surge water portion. A feeding unit (19) is used for transferring and transporting water and ash for subsequent treatment. An independent claim is included for the steam generator with wet pocket system.

Description

The Invention is directed to a wet scrubber system with a Water filled Wet bagger for cooling the more dusty in the combustion Coal arising in the pulverized coal firing of a steam generator Ash after discharge from the pulverized coal firing and with a swinging dehydrator drainage the resulting ash. Furthermore, the invention is directed a steam generator with wet scrubber system.

The demand for low NO _x combustion of fuels resulted in a finer grinding of the raw coal and at combustion chamber temperatures below the melting point of the ash. The resulting in such a pulverized coal ash is correspondingly fine-grained and takes on the cooling in the water bath of the wet ash on large amounts of water. Due to the high water content, this ash always brings difficulties in the further promotion, the bunkering and the marketing of the ashes.

The extremely wet ashes, whose residual moisture can be 50% or more, can with downstream belt conveyors poorly promoted become. About that In addition, soiling is in the entire lower strand of the conveyor can not be avoided. Steep or inclined conveyors under a slope from bigger than 10 ° are only conditionally or not at all possible. The bunkering of ashes in coarse silos is through with solids contaminated dripping water at the silo outlet with heavy soiling connected below the silo. The onward transport with trucks brings further pollution by a subsequent post-drainage on the vehicle along the entire transport route.

The difficulties mentioned above have not yet been satisfactorily solved. An increase in the combustion chamber temperature, which would have resulted in a different ash structure with a lower tendency to absorb water, failed because of the requirement for low levels of NO _x in the flue gas. Dewatering of the wet ash with the help of centrifuges or vacuum belt filters or by means of drainage facilities directly at the wet-box was not a decisive success.

From the EP 0 029 235 A1 For example, a system and method for removing ash removed from a coal-fired combustor is known. Here, the ash from the combustion chamber passes into a water-filled ash funnel from which it is attracted periodically or intermittently. Before emptying the ash hopper, the ash has a water content of 25%. The ashes are removed from the ash hopper by means of a stream of water, which sets a mixture of 20% ash and 80% water. The hydraulically conveyed ash is fed to a container, from which it is added for dewatering in a Schwingentwässerer. After the treatment of the ash in the Schwingentwässerer reaches the ash or the Schwingentwässerer leaving mixture again a water content of 25%.

From the DE 40 41 381 C1 For example, a wet ash pan in the form of an arcuate discharge chute for quenching slag in a water bath is known, which can be vibrated by means of a vibration generator to aid in dewatering the slag. This wet scrubber is used in connection with a coal combustion process and is characterized by the fact that the combustion residues are pushed out discontinuously by means of a discharge piston from the Ausschubschurre. A disadvantage of the method to be carried out with this device is that a discontinuous discharge takes place and that the entire device, ie the Ausschubschurre total is vibrated. Vibrations must be avoided for static reasons but especially in wet ash for coal dust combustion chambers, which are designed as a scraper conveyor with circumferential scraper chain with arranged thereon scrape, as they are known from DE 23 25 923 C2 are known.

Of the Invention is based on the object in a coal dust firing especially fine-grained and in non-molten form and in a water bath chilled Efficiently deashing ashes.

The The above object is achieved by a wet scrubber system solved with the features of claim 1. Advantageous embodiments The invention are the subject of the respective subclaims.

Farther the above object is achieved by a steam generator according to the invention solved with the features of claim 5.

Schwingentwässerer are z. B. from DE-OS 28 56 431 and DE-P5 30 13 668 known per se. These vibrating dehydrators have been used for drainage, screening and cleaning of sands. It turned out surprisingly that the special ash from a no _x-poor pulverized coal can be as far dehydrate by means of such Schwingentwässerers that the difficulties may have been effectively resolved.

Several embodiments The invention is illustrated in the drawings and will be described below explained in more detail.

It demonstrate

1 schematically a wet scrubber system,

2 a Schwingentwässerer in a wet scrubber system and

3 a Schwingentwässerer at another point within a wet scrubber system.

From a steam generator is only the lower part of a combustion chamber 1 shown, which is provided with a Kohlenstaubfeuerung. The coal dust firing is operated so that the content of nitrogen oxides in the flue gas is minimized.

For this purpose, on the one hand the raw coal is largely ground up and on the other hand in the combustion chamber 1 maintained a combustion chamber temperature which is below the melting point of the ash contained in the coal. The resulting ash during the combustion of the coal falls therefore fine-grained and dry, that is not melted on.

The ash passes according to 1 from the combustion chamber 1 for cooling in a wet scrubber 2 , The wet-boxer 2 consists of a trough filled with extinguishing water 3 which has a horizontal and a rising part. The wet-boxer 2 is with a water inlet 4 , an overflow 5 and an emptying line 6 Mistake. For sealing against the outside atmosphere is the lower part of the walls of the combustion chamber 1 by a dip 7 extended into the water bath inside the wet-bag 2 dips.

Inside the wet bag 2 runs a scraper chain conveyor 8th around. This scraper chain conveyor 8th carries the ash cooled in the water bath over a drop 9 at the end of the sloping part of the wet bag 2 out. The discharged ashes will be from one below the drop 9 arranged inclined conveyor 10 to an ash silo 11 promoted. The feeder can also be omitted, and the ash directly into the ash silo 11 be encouraged. The ash silo 11 is with a discharge organ 12 over the ash silo 11 on a conveyor belt 13 or a transport vehicle is emptied.

Due to its special structure, the ashes during cooling decrease within the water bath of the wet ash 2 large amount of water on. This water content, which can be up to 50% or more, interferes with the further transport and bunkering of the ashes. For this purpose, within the wet scrubber system is a Schwingentwässerer 14 arranged. This swing drainage 14 can be right behind the drop 9 of the wet-bag 2 ( 3 ), behind the discharge of the feederhouse 10 or, as in 2 pictured below the ash silo 11 be arranged.

For the basic structure of the Schwingentwässerers 14 include a swingable, with a vibratory drive 15 provided sieve box 16 in which a sieve plate 17 is arranged. The sieve box 16 has a discharge device on one end face 18 for the dewatered good. In the area of the other front side is located above the sieve tray 17 a task device 19 for the wet ash.

On the sieve bottom 17 the Schwingentwässerers 14 From the abandoned, wet ashes, the water is separated, located in a drip pan 20 which collects below the sieve box 16 is provided. At the lower part of the drip tray 20 is a lead 21 connected to a cyclone 22 or a cyclone plant consisting of several cyclones. In the line 21 is a pump 23 arranged the separated water to the cyclone 22 inflated. In the cyclone 22 are separated from the water, the suspended matter, which via a to the solids discharge of the cyclone 22 connected line 24 to the Schwingentwässerer 14 to be led back. The purified water gets out of the cyclone 22 either discharged or to the drip tray 20 returned and over the outlet 28 the drip tray 20 deducted ( 2 ). In the cyclone 22 also flows one with the overflow 5 of the wet-bag 2 connected line 25 one. The cleaning of the extinguishing water from the wet-box 2 can thus be integrated into the system of dewatering the ashes.

The dewatered ashes will go over the discharge facility 18 from the Schwingentwässerer 14 discharged and reaches a conveyor belt 26 that she z. B. in a silo 27 promotes. The ash has after treatment in the Schwingentwässerer 14 such a water content that it can be further promoted and stored without difficulty. In addition, the dewatered ashes characterized by a uniform water content, which facilitates the further processing of the ash.

Claims (5)

Wet scrubber system with a water-filled wet scrubber ( 2 ) for cooling the ashes of pulverized coal burning in the pulverized coal firing of a steam generator after the discharge from the coal dust tion and with a vibrating water separator ( 14 ) for dewatering the resulting ash, characterized in that the wet scrubber plant a wet scrubber ( 2 ) with a rising part with mechanical discharge of the fine-grained and in non-molten form incurred in the wet-type and ( 2 ) Water absorbing ash and a wet ash ( 2 ) downstream vibrating water ( 14 ) with a task device ( 19 ) for the wet ash to remove adhering water and transfer of the ashes into a transportable and further processable state. Wet scrubber system according to claim 1, characterized in that the Schwingentwässerer ( 14 ) immediately behind the discharge ( 19 ) of the wet bag ( 2 ) is arranged. Wet scrubber system according to claim 1, characterized in that the Schwingentwässerer ( 14 ) behind the dropping off of a conveyor ( 10 . 13 ) or below a silo ( 11 ) is arranged. Wet scrubber system according to one of claims 1 to 3, characterized in that the wet scrubber ( 2 ) an overflow ( 5 ), the line ( 25 ) with a cyclone ( 22 ) or a cyclone plant, and that the cyclone ( 22 ) or the cyclone plant has a solids discharge which is conductive ( 24 ) with the task side of the Schwingentwässerers ( 14 ) and that the water overflow of a drip pan ( 20 ) of the Schwingentwässerers ( 14 ) by line ( 21 ) with the cyclone ( 22 ) or the cyclone plant is connected. Steam generator with wet scrubber after a the claims 1 to 4 for drainage of during operation of the steam generator resulting ash.