EP0972988B1 - Method and apparatus for extracting water from combustion residues mechanically discharged from a wet slag remover - Google Patents

Description

The invention relates to a method for reducing the Water content of combustion residues, which from an oven into a tub of a wet slag remover and carried out from there by mechanical means are, according to the preamble of claim 1 and a device for reducing the water content from combustion residues in a wet slag remover according to the preamble of claim 10.

Combustion residues, for example from waste incineration plants cool down after the combustion process and the dust exposure for subsequent work steps, such as Interim storage and further transport, to be minimized the combustion residues from the furnace into a wet deslagger promoted. The wet purifier has one Tub with a water bath on which the combustion residue records and in which they are cooled. there the combustion residues take a lot of water on. When discharging the combustion residues from the Wet slag remover with mechanical conveyors, e.g. when discharging with one described in DE-A 3 731 140 Chain detoxifier, this water is also carried away. This is partly due to the higher weight of water-containing combustion residues undesirable.

In a generic from JP-A-57 142417 known device, the water-containing residues carried out along a discharge route. At the end of The discharge section is located on the underside Heating element, which heats the residues and a part the water contained in it evaporates. through one arranged above the discharge path The water vapor-containing air is extracted aspirated.

The object of the present invention is therefore to be inexpensive and economical way of water content with mechanical conveyors from a wet deslagger reduce discharged combustion residues.

This problem is solved by a method according to the Features of claim 1 and with a device according to the features of claim 10.

According to the combustion residues, while them by means of a mechanical conveyor a discharge section from a one containing a water bath Tub of a wet slag remover can be carried out with Extracted water with the help of a vacuum device. This The process has the advantage of extracting water can take place continuously in a relatively small space and in contrast e.g. to gravity-induced water withdrawal goes quickly.

The combustion residues are advantageously conveyed onto a filter grate of the vacuum device, which forms a section of the discharge path. With a negative pressure of 0.1 bar to 0.9 bar, water is removed from the combustion residues through the filter grate. Air or vapors are also sucked out by the negative pressure, which then entrains water from the combustion residues. Air flows of 10 to 100 Nm ³ / t combustion residue have proven to be particularly effective, the amount of air varying according to the type and composition of the combustion residue. The extraction of vapors also has the advantage that the temperature of the combustion residues is kept at a high level by the hot vapors during the water removal.

Part of the combustion residues conveyed to the filter grate advantageously remains as permanent Slag bed on the filter grate. The slag bed relieved maintaining negative pressure and serving as an additional filter.

By regular cleaning of the filter grate with compressed air and / or pressurized water can clog the Prevent filter rust. Cleaning is an advantage from the underside opposite the slag bed of the filter grate, as this is the permanent slag bed is not destroyed. A particular advantage with Use compressed air from the bottom of the filter grate here arises because not only by the compressed air the filter grate cleaned but also the slag bed is loosened up.

The combustion residues with a temperature from 60 ° C to 95 ° C on the filter grate of the vacuum device brought, you can with the water withdrawal from the these temperatures lower mechanical bond of the Water in the combustion residues benefit. The Water is easier to remove. As particularly cheap a temperature of 70 ° C to 80 ° C has been found.

Process steps up to a temperature of 60 ° C 95 ° C of the combustion residues in the area of the filter grate are e.g. avoiding cold blowing of combustion residues during the final phase of the combustion process in the oven. This can be done either by preheating the primary air or by throttling the same in last section of the oven can be reached. additionally the heat loss in the wet slag can be minimized, by the walls of at least the tub of the wet purifier be thermally insulated and the water bath in the Tub with heat-insulating floats, which also the Prevent evaporation of the water is covered.

That from the combustion residues via the vacuum device extracted water is pumped in the tub of the wet slag was pumped back. To this The water consumption in the wet purifier can be controlled in this way to reduce.

The device for extracting water from mechanical combustion residues discharged from a wet slag remover has a vacuum device according to claim 10 on. With the filter grate as a section of the Discharge can be the vacuum device with combustion residues be loaded, regardless of whether e.g. on Chain deslagger or a plate deslagger or a other mechanical means of conveying the combustion residues is provided. There are no additional ones Conveyor lines necessary, which e.g. is important if existing systems subsequently with the vacuum device to be equipped.

Advantageously, the water is in one on the bottom of the filter grate arranged tub or funnel-shaped suction chamber, which has a Pump is connected to the wet slag remover.

The filter grate is advantageously opposite one discharge level defined by the mechanical conveyor of the discharge route. Part of the on the filter grate conveyed combustion residues can form a permanent slag bed on the filter grate, about the further combustion residues to reduce their water content can be conveyed away.

In a preferred embodiment, the filter grate Openings up to 10mm in diameter, preferably of 5mm, on which is preferably against the bottom of the filter grate expand conically. So designed Openings largely prevent the openings from becoming blocked.

In another embodiment, are against the bottom of the filter grate are provided, by means of which the filter grate comes from below Compressed air and / or pressurized water can be cleaned. The The compressed air can also be supplied via an outlet the suction chamber. For this, the outlet is in one with a line connecting a vacuum pump Valve for controlling the compressed air supply opened and on second valve for controlling the vacuum closed.

Further preferred embodiments are the subject of further dependent claims.

Fig. 1

eine Prinzipskizze der Vorrichtung zum Entziehen von Wasser aus Verbrennungsrückständen mit Nassentschlacker und Unterdruckvorrichtung;

Fig. 2

eine Draufsicht auf zwei Absaugkammern der Unterdruckvorrichtung, wobei eine Absaugkammer ohne Filterrost, die andere dagegen mit montiertem Filterrost dargestellt ist; und

Fig. 3

einen Schnitt entlang der Linie III-III in Fig. 2 durch die fertig montierte Absaugkammer mit Filterrost.

The device is explained in more detail below using an example using the drawings. Show:

Fig. 1

a schematic diagram of the device for extracting water from combustion residues with wet slag and vacuum device;

Fig. 2

a plan view of two suction chambers of the vacuum device, one suction chamber without filter grate, the other, however, is shown with the filter grate installed; and

Fig. 3

a section along the line III-III in Fig. 2 through the assembled suction chamber with filter grate.

1 schematically shows a device 10 for reducing the water content of combustion residues 11 shown, which is discharged from a wet deslagger 12 become. In a tub 14 of the wet slag remover 12, the Walls 13, 13 ', 13' 'are provided with thermal insulation 15 are, there is a water bath 16, which with heat insulating Floats 17, e.g. with foam glass balls, is covered. In the tub 14 and the water bath 16 protrudes a slag shaft 18 through which the combustion residues 11 from a furnace 19 into the wet slag remover 12 arrive. The heat insulation 15 and the floats 17 prevent cooling of the water bath 16 and thus excessive heat loss from the combustion residues 11, so the latter ultimately with an ideal Temperature of 60 ° C to 95 ° C for drainage.

By preheating or throttling primary air 1, which in an end region 19 'of the furnace 19 can be supplied the combustion residues 11 with one compared to combustion residues 11 from normal combustion processes increased temperature in the wet deflasker 12 are introduced, which makes the preferred temperature from 60 ° C to 95 ° C more easily reached for drainage can be.

The combustion residues are removed from the bottom wall 13 'of the tub 14 11 over an incline leading upwards Wall 13 '' of the wet deslagger 12 using a mechanical Funding means 20 discharged from the wet slag cleaner 12. In the example shown here, compare also Fig. 3, as a conveyor 20 is a chain deslacker 21 with one in guide profiles 22 and over sprockets 24 guided chain 23 shown. The sloping wall 13 '' forms part of a discharge section 26, in the End region 25, a filter grate 32 of a vacuum device 34 forms a section 25 'of the discharge section 26.

So that the heat-insulating float 17 is not together with the combustion residues 11 by means of the mechanical Funding means 20 discharged from the water bath 16 be at the water level, easily immersed in water, a lock 31 which prevents that the float 17 to the inclined wall 13 '' and thus get into the area of the discharge section 26. The lock 31 can on the side walls or the ceiling of the Wet purifier 12 attached and for example in shape a board or a plate or in the form of a stable curtain.

A serves between the water bath 16 and the filter grate 32 along the sloping wall 13 '' of the wet purifier 12 extending route section 27 of the discharge route 26 as a draining line. As explained in more detail below will lose the combustion residues 11 on this Section 27 due to gravity a first part of the water discharged from the water bath 16. To have the combustion residues 11 cover the entire discharge path 26 including filter grate 32 happens, they arrive at Interim storage via a shaft 28 in a bunker 29th

The filter grate 32 has a suction chamber on its underside 33 30 on that via a line 36 with a vacuum container 38 and over this with a vacuum source 40 is connected in the form of a vacuum pump. The vacuum container 38 is also a Peristaltic pump designed pump 42 with the tub 14 of the wet slag remover 12 connected. With the help of the pump 42 becomes the polluted water that the combustion residues 11 is withdrawn into the tub 14 of the wet slag remover 12 pumped back. About the vacuum device 34 can also vapors 43, i.e. Water vapor, and possibly hot gases contained in the furnace 19, aspirated through the combustion residues 11 which also contributes to the drainage Combustion residues 11 at a favorable temperature keep from 60 ° C to 95 ° C.

In the example shown in Fig. 2, two are side by side arranged suction chambers 30a, 30b of the vacuum device 34 pictured. The two suction chambers 30a, 30b are shown in plan view, with suction chamber 30a is shown with mounted filter grate 32, while suction chamber 30b without filter grate 32 is shown. 3 is the suction chamber 30a with the filter grate 32 installed in section along the line III-III shown in Fig. 2 shown. The direction of discharge A is in each case by a Arrow marked.

The suction chambers 30a, 30b are designed as troughs, which by frame plates 44, 44 ', end walls 46, 46' and a bottom plate 48 are formed. The immediately adjacent side walls of the suction chambers 30a, 30b are formed by a common frame plate 44 '. The suction chambers are via the frame plates 44, 44 ' 30a, 30b on a support structure 45 of the discharge section 26 attached. At about the lowest Point 49 of the suction chambers 30a designed as tubs, 30b, an outlet 50 is provided which leads into a tube 52 a pipe flange 54 opens. With the help of the pipe flange 54, the tube 52 can be connected to a second tube 53 or a Hose 53 'are connected as shown with dashed lines Lines is indicated in Fig. 3. The tube 52 forms together with the pipe flange 54 and the hose 53 'or the second pipe 53 is the line 36 shown in FIG. 1 between the suction chamber 30 and the vacuum container 38th

As can be clearly seen in FIGS. 2 and 3, the End walls 46, 46 'and on the frame plates 44, 44' Support strips 56 arranged with a seal 58 on the the filter grate 32 rests in the assembled state. As a fastening unit for the filter grate 32 is in the discharge direction A the suction chamber 30 upstream of the two Under hook bars 60 connecting frame plates 44, 44 'are provided. The lower hook beam takes over when assembled 60 in cooperation with an approximately perpendicular to Under hook bar 61 protruding from the filter grate 32 Function of an abutment. In discharge direction A of the suction chamber 30 are located below the front wall 46 two fastening flanges arranged on the frame plates 44, 44 ' 62 provided. The mounting flanges 62 have fastening openings 64, which are against the central longitudinal axis 66 of the suction chamber 30a, 30b open are. The filter grate 32 has a front plate 68 and one fastening plate each 70 fastening elements 67, such as screws, pins or bolts connected. The in Example shown here used as fastener 67 Screws can from the central longitudinal axis 66 Suction chamber 30a, 30b forth laterally into the fastening openings 64 will be introduced. You will be using a Nut 72 secured and the filter grate 32 between the Lower hook beam 61 and the mounting flanges 62 clamped.

The filter grate 32 is a route section in the discharge direction A. 27 upstream of the discharge section 26. On this Section 27 becomes the combustion residues 11 with the help of the chain detoxifier already mentioned 21 on a transport surface 73 along the sloping wall 13 '' of the wet slag remover 12 transported upwards. On the chain 23 of the chain deslagger 21 are drivers 76 attached, each one across the discharge path Have 26 extending traverse 78. The trusses 78 take from the bottom 13 'of the tub 14 of the wet purifier 12 each with combustion residues 11 and push this ahead. In the area of route section 27 and in section 25 'of the discharge section 26 Trusses 78 with their lower edges 78 'along one Discharge level 74 out opposite the transport surface 73 a little, i.e. for example 1 cm apart is, as can be seen in Fig. 3. This can be done the combustion residues 11 escaping water due to gravity, also known as the draining line Route section 27 of the discharge route 26 down into run back the tub 14 of the wet slag remover 12. The Combustion residues 11 already lose on this Section 27 a part of the from the tub 14th of the wet slag remover 12 with discharged water.

3, the filter grate 32 is opposite the discharge plane 74 is set back. The Distance to the lower edge 78 'of the filter grate 32 moving trusses 78 is between 2 cm and 10 cm, preferably 4 cm to 7 cm. Through this distance can a permanent slag bed on the filter grid 32 80 are built, via which the driver 76 of the chain deslagger 21 with their traverses 78 more Can convey combustion residues 11 away. The top one Slag layer of the slag bed 80 can under Circumstances removed and newly introduced Combustion residues are newly formed. The Slag bed 80 on the filter grate 32 makes it easier to from the suction chamber 30a, 30b to the filter grid 32 maintain negative pressure and acts also as an additional filter.

The filter grate 32 points in a grid in this example arranged openings 82 with a radius of 5mm on, which expand conically towards its underside 33. The grid spacing 83 between the centers of the in approximately circular openings 82 are between 10 and 40 mm, preferably at 25 mm.

In the first end wall 46 'seen in the discharge direction A the suction chamber 30 are two directed against the filter grate 32 Nozzles 84 are provided, by means of which the filter grate 32 cleaned with pressurized water 85 and / or pressurized air 85 ' can be. The nozzles 84 can both with compressed air 85 'and operated with pressurized water 85. It however, different nozzles 84 can also be provided, one for compressed air 85 ', the other for pressurized water 85 are provided. The nozzles 84 can be moved, controllable or rigidly stored. It is also conceivable such nozzles 84 in the other end wall 46 or in one to arrange the frame plates 44, 44 'or the base plate 48. Compressed air 85 'can also pass through the outlet 50 in the bottom plate 48 of the suction chamber 30 against the filter grate 32 are pressed. To do this, line 36 must connected to a compressed air supply 88 via a valve 86 be, as shown in Fig. 1. Another one Valve 86 'or via a two-way valve 86.86' must the line 36 from the vacuum pump and the vacuum container be uncouplable. When applied of the filter grate with a correspondingly large volume flow the compressed air 85 'loosens the slag bed 80 and can perceive its filter function better. The pressure water 85 is next to the bottom 33 of the filter grate 32 also flushed the line 36 and cleaned. A cleaning cycle can be, for example Cleaning with pressurized water 85 every 10 min and one cleaning with compressed air 85 'every 60 min, using compressed air 85 'and pressurized water 85 each set for about 10s become. The vacuum drops in this short time from.

Are a plurality of filter gratings 32 in a discharge section 26 can be arranged one behind the other and / or next to one another Cleaning the grids are done serially, so never all Gratings have a falling negative pressure at the same time.

In the example shown, two filter gratings 32 are side by side with two suction chambers 30 as section 25 'of Discharge section 26 is provided. But it is also conceivable that the two filter gratings 32 on their underside by one common suction chamber 30 are enclosed. ever according to the width of the discharge path 26 and the stability requirements but can also only one or more than two filter gratings 32 and suction chambers 30 may be provided.

If necessary, as mentioned, several filter gratings can also be used 32 and suction chambers 30 in the discharge direction A one behind the other be arranged. The suction chambers 30 can take place be designed as a tub as a funnel. The section 25 'of the discharge path 26 through the filter grate 32 is not necessarily formed in the end region 25 the discharge path 26 may be arranged. Likewise need to the openings 82 are not necessarily conical towards the underside 33 of the filter grate 32 expand.

If instead of the chain deslagger 21 e.g. a plate purifier provided, the filter grate 32 is opposite one through the transport surface 73 of the plate deslaker defined discharge level 74 arranged set back. In such a case, the transport of combustion residues 11 via the filter grate 32, can this be designed as a shaking bed and for example also arranged inclined downwards in the discharge direction A. his.

The reduction of the water content according to the invention Method and the device according to the invention 10 can also be used with cold or lukewarm combustion residues 11 perform. This saves costs for thermal insulation and changing the combustion process but reduces efficiency.

Claims (16)

1. Process for reducing the water content in combustion residues (11) which pass from a furnace (19) into a tank (14) of a wet slag remover (12) and, from there, are discharged along a discharge section (26) by mechanical conveying means (20), water which is discharged from the wet slag remover (12) with the combustion residues (11) being removed by means of a vacuum device (34), characterized in that the combustion residues (11) are conveyed onto a filter grating (32) of the vacuum device (34), which is connected to a vacuum source (40) via its underside (33).
2. Process according to Claim 1, characterized in that the vacuum which is present at the underside (33) of the filter grating (32) is 0.1 bar to 0.9 bar, and the water is preferably trapped in a suction chamber (30) which is arranged on the underside (33) of the filter grating (32).
3. Process according to Claim 2, characterized in that some of the combustion residues (11) which are conveyed onto the filter grating (32) remains on the filter grating (32), where it forms a bed of slag (80).
4. Process according to one of Claims 2 to 3, characterized in that the combustion residues (11) are conveyed from the furnace (19) into the wet slag remover (12) and out of the latter in such a manner that they are at a temperature of from 60° to 95°C, preferably 70°C to 80°C, when they reach the filter grating (32) in order for water to be removed.
5. Process according to Claim 4, characterized in that the heat losses from the combustion residues (11) leaving the furnace (19) in the wet slag remover (12) are minimized by thermal insulation (15) of the walls (13, 13', 13") of the wet slag remover (12) and by adding heat-insulating floating bodies (17) to a water bath (16) which is located in the tank (14) of the wet slag remover (12) and receives the combustion residues (11).
6. Process according to Claim 4 or 5, characterized in that, preferably by preheating and/or throttling primary air (1) at the end of the combustion process, the combustion residues (11) which pass from the furnace (19) into the wet slag remover (12) are at a higher temperature than combustion residues (11) from a combustion process carried out without these measures.
7. Process according to one of Claims 2 to 6, characterized in that vapours (43) and/or hot air are sucked out of the furnace through the combustion residues (11) by means of the vacuum device (34).
8. Process according to one of Claims 2 to 7, characterized in that the filter grating (32) of the vacuum device (34) is regularly cleaned with compressed air (85') and/or pressurized water (85), the cleaning preferably taking place from the underside (33) of the filter grating (32).
9. Process according to one of Claims 1 to 8, characterized in that water which is extracted from the combustion residues (11) is fed back to the wet slag remover (12) via a pump (42).
10. Apparatus for reducing the water content of combustion residues (11) which have passed from a furnace (19) into a wet slag remover (12), comprising a wet slag remover (12) with a tank (14) which contains a water bath (16), a discharge section (26), a mechanical conveying means (20), the conveying means (20) discharging the combustion residues (11) from the tank (14) of the wet slag remover (12) along the discharge section (26), and a vacuum device (34), characterized in that a part (25') of the discharge section (26) is formed by a filter grating (32) of the vacuum device (34), which is connected via its underside (33) to a vacuum source (40).
11. Apparatus according to Claim 10, characterized in that the filter grating (32) is set back, preferably by up to 10 cm, with respect to a discharge plane (74) which is defined by the mechanical conveying means (20).
12. Apparatus according to Claim 10 or 11, characterized in that the filter grating (32) has openings (82) with a diameter of up to 10 mm, preferably of 5 mm, which preferably widen conically towards its underside (33).
13. Apparatus according to one of Claims 10 to 12, characterized in that the filter grating (32), on its underside (33), has a suction chamber (30) which is designed as a tank or funnel (44, 44', 46, 46', 48) and which, approximately at its deepest point (49), has an outlet (50), via which the suction chamber (30) is connected via a pump (42) to the tank (14) of the wet slag remover (12).
14. Apparatus according to Claim 13, characterized in that compressed air (85') can be applied to the filter grating (32) via the outlet (50).
15. Apparatus according to one of Claims 10 to 14, characterized in that nozzles (84) which are directed towards the underside (33) of the filter grating (32) are provided, with the aid of which nozzles the filter grating (32) can be cleaned from the underside (33) using pressurized water (85) and/or compressed air (85').
16. Apparatus according to one of Claims 10 to 15, characterized in that the tank (14) of the wet slag remover (12) has walls (13, 13', 13") with a thermal insulation (15), and that a water bath (16) which is present in the tank (14) of the wet slag remover (12) is covered with thermally insulating floating bodies (17), the floating bodies being prevented from passing into the area of the discharge section (26) by a barrier (31).

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