EP1085264A1 - Process and apparatus for water cooling of a combustion grate - Google Patents

Abstract

A waste heat boiler (3) is connected in downstream of the fire chamber (2) and supplied with supply water (23) of which a part is removed after the water pump (25) and before the water regulating valve (26) from the water pipe (22) and directed through at least one pressure drop point (20) from where it is then supplied as cooling water (15) to the cooling channels (14). On passing through the cooling channels the cooling water is heated up to at least saturated steam temperature and is then supplied to the remote heat supply device or economiser.

Description

Technical field

The invention relates to a method for cooling a grate for a combustion chamber by means of water and a grate for the combustion of solids, in particular Waste such as household and urban waste, which essentially consists of in rows and side by side water-cooled grate covering units.

State of the art

It is known prior art, lumpy solids, such as. B. waste, in one Combustion chamber in which primary air is added and a downstream one Afterburning chamber in which secondary air is added to burn. The solid is usually reacted on a combustion grate. Such grids usually consist of several rows of grids, one behind the other arranged and overlap like a roof tile, alternating fixed and movable rows are arranged. The rows are out Rust covering units, e.g. B. from tightly connected narrow Grate bars or larger grate plates.

With air-cooled combustion grates, the primary air is under the grate fed and flows in from the underwind zones through openings in the grate the solid bed above. This cools the grate (Thomé-Kozmiensky, K. J .: Thermal waste treatment, EF publishing house for energy and Umwelttechnik GmbH, 2nd edition 1994, p. 157). The combustion air is thus first used for cooling and then for combustion. With the Linking the combustion air and the cooling air must compromise between fire control and cooling, which adversely affect the Limit the area of use of the grate. In addition, the Combustion air ducts / slits easily because they are in direct contact with the burning garbage. Such a blockage then also blocks the Cooling air so that cooling fails.

• Die notwendigen Luftmengen bedingen sehr grosse Luftzufuhr- und Luftabfuhrleitungen, die schwierig in die Rostkonstruktion zu integrieren sind.
• Der Leistungsbedarf für die Kühlluftpumpen ist gross, da die Gasgeschwindigkeit der Kühlluft in den Platten hoch sein muss, um einen genügend guten Wärmeübergang zu erreichen, und damit ist der Druckabfall ebenfalls gross.

Grate cooling systems in which the heat is dissipated with a separate air circuit have the following disadvantages:

• The necessary air volumes require very large air supply and air discharge lines, which are difficult to integrate into the grate construction.
• The power requirement for the cooling air pumps is high, since the gas velocity of the cooling air in the plates must be high in order to achieve a sufficiently good heat transfer, and the pressure drop is therefore also great.

In addition to the air-cooled combustion grates, there are also water-cooled ones Combustion grates with a cooling water system separated from the primary air known, for example in EP 0 621 449 B1, EP 0 757 206 and DE 44 00 992 C1 described.

• Eine Wärmenutzung der abgeführten Wärmemenge ist wegen dem tiefen Temperaturniveau nur schwer oder überhaupt nicht möglich.
• Um bei einer Komponentenhavarie oder bei einem Ausfall des Wärmeabnehmers die Kühlung sicherzustellen, muss ein Notkühlsystem eingesetzt werden, was zusätzliche Investitionskosten verursacht.
• Es muss durch geeignete Massnahmen verhindert werden, dass sich in den Rostplatten/Roststäben Dampfpolster bilden, welche die Kühlung lokal verunmöglichen und zu gefährlichen Dampfschlägen führen können.
• Wasserzufuhr und Wasserabfuhr erfolgen über flexible Wasserschläuche, welche schadensanfällig sind.
• Da die Rosttemperatur immer relativ tief liegt, geht die Wärmeenergie, die zur besseren Verbrennung durch die Luftvorwärmer zugeführt wird, anstelle in da Müllbett zu einem beträchtlichenTeil in das Kühlwasser.

The grate cooling systems that dissipate heat at water temperatures below 100 ° C have the following disadvantages:

• It is difficult or even impossible to use the amount of heat dissipated due to the low temperature level.
• In order to ensure cooling in the event of a component breakdown or in the event of a heat consumer failure, an emergency cooling system must be used, which causes additional investment costs.
• Appropriate measures must be taken to prevent steam cushions from forming in the grate plates / grate bars, which can make cooling locally impossible and lead to dangerous steam strikes.
• Water supply and drainage take place via flexible water hoses, which are prone to damage.
• Since the grate temperature is always relatively low, the thermal energy which is supplied by the air preheaters for better combustion goes to a considerable extent in the cooling water instead of in the garbage bed.

• Eine Wärmenutzung der abgeführten Wärmemenge ist zwar möglich, erfordert aber in der Regel einen Wärmetauscher. Wird die Wärme nach aussen abgegeben, z. B. in eine Fernwärmesystem, so ist die Gleichzeitigkeit des Betriebes von Rostkühlung und Fernwärme nicht immer gegeben.
• Um bei Komponentenhavarie oder beim Ausfall des Wärmeabnehmers die Kühlung sicherzustellen, muss ein Notkühlsystem eingesetzt werden, welches zusätzliche Investitionskosten verursacht.
• Es muss durch geeignete Massnahmen verhindert werden, dass sich in den Rostplatten/Roststäben Dampfpolster bilden, welche die Kühlung lokal verunmöglichen und zu gefährlichen Dampfschlägen führen können.
• Wasserzufuhr und Wasserabfuhr erfolgen über flexible Wasserschläuche, welche schadensanfällig sind.
• Zum Teil geht auch hier die Wärmeenergie, die zur besseren Verbrennung durch den Luftvorwärmer zugeführt wird, anstelle in das Müllbett in das Kühlwasser.

The grate cooling systems that dissipate heat at water temperatures above 100 ° C (water pressure> 1 bar) have the following disadvantages:

• It is possible to use the amount of heat dissipated, but it usually requires a heat exchanger. If the heat is released to the outside, e.g. B. in a district heating system, the simultaneous operation of grate cooling and district heating is not always given.
• In order to ensure cooling in the event of a component breakdown or in the event of a heat consumer failure, an emergency cooling system must be used, which causes additional investment costs.
• Appropriate measures must be taken to prevent steam cushions from forming in the grate plates / grate bars, which can make cooling locally impossible and lead to dangerous steam strikes.
• Water supply and drainage take place via flexible water hoses, which are prone to damage.
• Here, too, part of the heat energy that is supplied by the air preheater for better combustion goes into the cooling water instead of the garbage bed.

• Da die Wassergeschwindigkeit gering ist, ist die Bildung von Dampfpolstern nicht auszuschliessen, so dass lokal die Kühlung verunmöglicht wird. Dieses Problem könnte zwar mit einer Umwälzpumpe gelöst werden, aber das verteuert einerseits das System, andererseits hängt dann die Betriebssicherheit des Systems an der Funktion der Pumpe.
• Die Wasserzufuhr und die Wasserabfuhr können nicht über flexible Schläuche erfolgen, da die Temperatur und der Druck des Wassers zu hoch sind. Der Naturumlauf erfordert relativ grosse Rohre für die Zu- und Abfuhr des umlaufenden Wassers. Mit diesen grossen Rohren ist es praktisch unmöglich, die bewegten Rohrreihen mit Wasser zu versorgen.

The grate cooling systems, which dissipate the heat with boiler water from the drum (water pressure approx. 40 bar, cooling takes place in natural circulation or forced circulation), as is known, for example, from DE 195 08 899 A1, have the following disadvantages:

• Since the water speed is low, the formation of steam cushions cannot be ruled out, so that local cooling is impossible. This problem could be solved with a circulation pump, but on the one hand this makes the system more expensive, on the other hand the operational reliability of the system depends on the function of the pump.
• The water supply and the water drainage cannot take place via flexible hoses, because the temperature and the pressure of the water are too high. Natural circulation requires relatively large pipes for the supply and discharge of the circulating water. With these large pipes, it is practically impossible to supply the moving rows of pipes with water.

Presentation of the invention

The invention tries to avoid these disadvantages. You have the task is based on a simple, efficient method for cooling a grate for one Fire chamber using water and a suitable grate for burning Develop solids, especially waste, that ensure that always cooling water in sufficient quantity, with sufficient pressure and in impeccable quality is available, so on an emergency cooling system can be dispensed with. The grate should be made of inexpensive material. In addition to the movable and fixed rows of grate bars also the central beams, side end panels and the fall of the grate be coolable in the same way. The heat consumption should be ensured in all operating cases his.

According to the invention, this is the case with a method according to the preamble of Claim 1 achieved in that part of the feed water after the Feed pump and before the feed water control valve from the feed line removed and passed over at least one pressure drop point and then the cooling channels in the grate lining units as cooling water Middle beams, side walls and falling of the grate is fed, the Cooling water when flowing through the cooling channels at least close to Saturated steam temperature is heated and then fed to a customer becomes.

As the perfect functioning of the water supply for every boiler operation (Water treatment, water supply, boiler feed pump) indispensable Prerequisites is always a great deal of effort is put into this Ensure water supply. By now the cooling water for the Incineration grate is tapped from this safe source, d. H. as cooling water demineralized, degassed boiler feed water is used for the grate advantageously ensures that there is always sufficient cooling water with enough pressure and in perfect quality is available.

Another advantage is that when an existing grate furnace is converted on the grate cooling according to the invention, the cooling system without large additional effort connected to the existing feed water pump because the amount of water delivered by the feed pump does not increase becomes. Because a discharge of the amount of heat dissipated into the drum of the boiler is always possible, it can also advantageously dispense with an emergency cooling system become.

According to the invention, the object of the invention is in accordance with a grate Preamble of claim 9 achieved in that the cooling channels one have a comparatively small inner diameter, its maximum size is designed in such a way that water and steam do not separate, and that the connecting lines (supply and discharge lines) to move Grate parts have an inner diameter that is smaller than that Inner diameter of the cooling channels. The supply lines are between Feed water pump and feed water control valve with the feed water line connected, and there is at least one pressure drop point in the supply lines arranged.

The advantage of the invention is that the cooling system with little Water is operable because all the warmth and part of the sensible Evaporation heat can be used. Therefore, the cooling tubes can only have a small diameter. This in turn has the advantage of being dangerous there is no steam / water separation.

Thanks to the 100% safe water supply, no emergency running properties for The grate covering units must be granted as material for the cast rust covering units no expensive high-alloy steel castings are used become, which leads to a cost reduction.

It is expedient if, as a consumer of the heated cooling water or Cooling water / steam mixture used either the drum of the boiler (then cooling takes place at the pressure and temperature level of the Drum and the coolant temperature and the material temperature in the Row of grate pads is about constant), or other customers, such as. B. District heating supplier, feed water tank, air preheater are used at where the steam pressure can be lower than the drum pressure, which advantageously causes a lower grate unit temperature.

It is also advantageous if the cooling water / steam mixture is one Steam separator is fed, the separated steam into the drum is passed and the remaining saturated water into the feed water is returned. It can also be used to preheat the cooling water.

It is advantageous if there is a pressure drop in the at least one pressure drop point is generated in the cooling water, which is at least ¼ of the pressure drop between the exit from the feed water pump and the entry into the drum. In this way, an approximately constant level is achieved in all cooling circuits Cooling water flow reached.

Furthermore, it is expedient if orifices, thin pipes, as pressure drop points or valves are used, the latter having the disadvantage that they are expensive are.

It is advantageous if the supply and discharge lines for the cooling water are included at least one expansion circle are executed. As a result of the small It is the diameter of the lines and the arranged expansion circles thus possible without problems the thermal expansions and the movements to compensate for the moving grate covering units or a partial grate.

Finally, it is expedient if there are several per row of grate coverings parallel cooling circuits are provided, the number of which depends on the thermal Load on the parts to be cooled is dependent.

Brief description of the drawing

Several exemplary embodiments of the invention are shown in the drawing.

Fig. 1

einen Längsschnitt einer schematisch dargestellten Müllverbrennungsanlage;

Fig. 2

eine schematische Darstellung des Kühlsystems eines wassergekühlten Rostes mit nachgeschaltetem Kessel in einer ersten Ausführungsvariante der Erfindung, bei welcher als Abnehmer des erwärmten Kühlwassers bzw. des Wasser/Dampf-Gemisches die Trommel des Kessels fungiert und Ventile als Druckabfallstellen eingesetzt sind;

Fig. 3

eine schematische Darstellung des Kühlsystems eines wassergekühlten Rostes mit nachgeschaltetem Kessel in einer zweiten Ausführungsvariante der Erfindung, bei welcher als Abnehmer des erwärmten Kühlwassers bzw. des Wasser/Dampf-Gemisches die Trommel des Kessels fungiert und Blenden als Druckabfallstellen eingesetzt sind;

Fig. 4

eine dritte Ausführungsvariante der Erfindung analog zu Fig.2, bei welcher als Abnehmer des erwärmten Kühlwassers bzw. des Wasser/Dampf-Gemisches der Speisewassertank fungiert;

Fig. 5

eine vierte Ausführungsvadante der Erfindung analog zu Fig.2, bei welcher als Abnehmer des erwärmten Kühlwassers bzw. des Wasser/Dampf-Gemisches der Luftvorwärmer fungiert;

Fig. 6

eine fünfte Ausführungsvariante der Erfindung analog zu Fig.2, bei welcher als Abnehmer des Wasser/Dampf-Gemisches ein Dampfabscheider fungiert, von welchem den Dampf in die Trommel und das Sattwasser in das Speisewasser geführt wird;

Show it:

Fig. 1

a longitudinal section of a schematically illustrated waste incineration plant;

Fig. 2

a schematic representation of the cooling system of a water-cooled grate with a downstream boiler in a first embodiment of the invention, in which the drum of the boiler acts as a consumer of the heated cooling water or the water / steam mixture and valves are used as pressure drop points;

Fig. 3

a schematic representation of the cooling system of a water-cooled grate with a downstream boiler in a second embodiment of the invention, in which the drum of the boiler acts as a consumer of the heated cooling water or the water / steam mixture and orifices are used as pressure drop points;

Fig. 4

a third embodiment of the invention analogous to FIG. 2, in which the feed water tank acts as a consumer of the heated cooling water or of the water / steam mixture;

Fig. 5

a fourth embodiment of the invention analogous to Figure 2, in which acts as a consumer of the heated cooling water or the water / steam mixture of the air preheater;

Fig. 6

a fifth embodiment of the invention analogous to Figure 2, in which acts as a consumer of the water / steam mixture, a steam separator, from which the steam is fed into the drum and the saturated water into the feed water;

Only the elements essential for understanding the invention are shown. The direction of flow of the media is indicated by arrows.

Way of carrying out the invention

The invention is explained below using exemplary embodiments and FIG. 1 to 6 explained in more detail.

Fig. 1 shows a longitudinal section of a schematically shown Waste incineration plant, which essentially consists of a water-cooled Combustion grate 1, a combustion chamber 2 arranged above it and one downstream boiler 3 with vertical empty trains 4 and a horizontal one Bundle train 5 exists. The firing material 6, in this case garbage, is placed on the grate 1 abandoned and burned with the supply of primary air 7 and 8 secondary air. The The resulting smoke gases 9 enter the boiler 3 and flow under them Dissipation of heat through the vertical empty trains 4 and the horizontal Bundle train 5 of the boiler 3 and are then not shown Flue gas cleaning system supplied. To this extent, such systems are known.

Fig. 2 shows a schematic representation of the cooling system of the water-cooled grate 1 with downstream boiler 3 in a first Embodiment variant of the invention. The grate 1 consists essentially of several rows (10.1, 10.2, 10.3 ...) of side by side Grate covering units 11. In Fig. 2 are examples of a thermally highly stressed Row 10.1 and two low thermal loads rows 10.2 and 10.3 are shown, the row 10.2 is a fixed grating unit row and the row 10.3 is to represent a moving row of grate pads and the two rows 10.2 and 10.3 are connected by a flexible connecting line 38. The Grate covering units 11 can be narrow grate bars or wider grate plates. Adjacent rows overlap like tiles. It can be lengthways of the grate alternately moving and fixed rows may be arranged or all rows can be moved. The grate 1 also has side walls 12 on.

Are the grate covering units 11 side by side in several grate tracks arranged, then these grate tracks are separated from one another by central beams 13 Cut. In the grate covering units 11, the side walls 12, the central beam 13 and the fall of the grate, not shown, cooling channels 14 for Application of cooling water 15 is arranged, which in Fig. 2 only in the Grate covering unit row 10.3 is shown schematically. The cooling channels 14 are preferably coils cast into the grate covering units 11, which are connected to supply lines 16 and discharge lines 17, the Lines 16, 17 are thin tubes, each of which has an expansion circle 18 can have. The cooling channels 14 are comparatively small Inner diameter, for example 14 mm. This is designed in such a way that there is no separation of water and steam in the pipes. The Inner diameter of the feed lines 16 is much smaller than that Inner diameter of the cooling channels 14, for example 8 mm. The Inner diameter of the discharge lines 17 is due to the Vapor phase slightly larger than that of supply lines 16, but still much smaller than the diameter of the cooling channels 14 in the Grate covering units 11.

In each supply line 16 are a three-way valve 19 and at least one Pressure drop point 20 installed. In the present first exemplary embodiment 2, these pressure drop points are 20 throttle valves.

The supply lines 16 all branch off from a line 21, which in turn branches off from the feed water line 22, in which boiler feed water 23 from Feed water tank 24 via the feed water pump 25 and that Feed water control valve 26 via the economizer 27 in the drum 28 of the Boiler 3 is passed. The branching of line 21 from line 22 takes place after the feed water pump 25 and before the feed water control valve 26.

The discharge lines 17 of the cooling systems each have check valves 29 and open into a collecting line 30 which connects to the drum 28 of the boiler 3 connected. The drum 28 is still with an evaporator 31 and a superheater 32 with a water injection 33, which via a Injector 36 is regulated in connection.

The cooling system of the grate consists of several connected in parallel Subsystems. A subsystem for cooling is shown by way of example in FIG. 2 of the side walls 12, a subsystem for the cooling of a row of grating units 10.1 in the thermally highly stressed part of the grate 1, a subsystem for the Cooling of two grate lining unit rows 10.2 and 10.3 in the thermally lower loaded part of the grate 1 and a subsystem for cooling the central beams 13.

For cooling the grate covering units 11, the side walls 12 and the central beams 13 cooling water 15 is used, which is a partial stream of demineralized degassed feed water 23 for the operation of the boiler 3. This cooling water 15 fits the economizer 27, it is after the feed water pump 25 and before the feed water control valve 26 removed from the feed line 22 and flows via line 15 into the supply lines 16 of the parallel subsystems of the Cooling system. By choosing this withdrawal point after the Feed water pump 25 and before the feed water control valve 26 is a secure cooling water supply with largely constant pressure guaranteed.

The grate cooling thus takes place parallel to the economiser operation. Because part of the Boiler feed water is used as cooling water 15, stands for grate cooling there is always enough water available, which is also perfect Quality and sufficient pressure.

The supply and discharge of the cooling water 15 to the grate components to be cooled 11, 12, 13 takes place via lines 16 and 17, which pipes with very small Are diameters. Thanks to this small diameter, they are so flexible that the movement of the grate covering units or a partial grate, the z. B. +/- 350 mm may be involved without further ado. The one shown in Fig. 2 In variant embodiments, expansion circles 18 are provided in the lines 16, 17 to compensate for the movement or the thermal expansions. Of course, the lines 16, 17 can also be made without expansion circles 18 be formed, as in FIG. 2 in the partial cooling system of the central beam 13 is shown.

In each subsystem is in the cooling water 15 on the at least one in the Line 16 arranged throttle valve 20 causes a pressure drop, which at least ¼ of the pressure drop between the outlet from the Feed water pump 25 and entry into the drum 28 is.

The cooling water 15 is used for cooling the grate covering units 11 Side walls 12 and the central beam 13 at least up to close to the Saturated steam temperature warmed up. In the normal case, the cooling water 15 except for the Saturated steam temperature warmed so that part of the water 15 evaporates. The Cooling water can also be completely or to a large extent (steam content> 0.3) evaporate, d. H. cooling is based on the single-tube boiler principle.

The heat from the rust components to be cooled is combined with the water or removed the water / steam mixture. Flows per subsystem of the cooling system very little cooling water 15, so all the sensible heat and part of it Evaporation heat is used. Therefore, the cooling channels 14, that is Cooling pipes only of a relatively small diameter. Here again has the advantage that steam and water do not separate. Thanks to the always safe Water supply for cooling does not require the guarantee of emergency running properties, so that no expensive high-alloyed as rust material Cast steel can be used, but cheaper low-alloy material can be used.

The heated cooling water or water / steam mixture is discharged on the outlet side the lines 17 into a collecting line 30 and from there into the drum 28 guided. The cooling takes place at a pressure and temperature level that is only slightly above that of the drum 28. The advantage is that the delivery of the dissipated amount of heat in the drum 28 is always possible.

Since the amount of heat generated in different grate covering unit rows 10.1, 10.2 can be very different, it is advantageous to have an automatic scheme to provide. This is based on the dashed line in the middle of FIG. 2 clarifies. A TCA temperature control system measures the outlet temperature of the heated cooling medium in line 17. The corresponding signals are passed to the valve 20, which depends on the respective Temperature level controls the amount of cooling water to be supplied 15, d. H. at a high temperature value, the valve 20 will open further, so that more Cooling water 15 is passed into the corresponding cooling channels 14 than at one lower temperature. In this way, the cooling can be optimized in which case slightly superheated steam is generated (single-tube boiler principle).

Fig. 3 shows a schematic representation of the cooling system water-cooled grate with downstream boiler in a second Embodiment variant of the invention. This differs from that in FIG. 1 illustrated and described above only in that as Pressure drops 20 orifices can be used. This is compared to that first embodiment variant cheaper. Thin tubes or manually operated needle valves can be used.

It is possible to use the heated cooling water or the cooling water Lead steam to another customer. The warmed up Cooling water supplied to part of the steam network. In which the pressure is deeper is than the drum pressure. This is shown in Figures 4 to 6.

Fig. 4 shows a third embodiment of the invention analogous to Fig. 2, in which as a consumer of the heated cooling water 15 or the water / steam mixture not the boiler 28, but the feed water tank 24 functions.

In the variant shown in Fig. 5, however, the customer is the Air preheater (economiser 27) or, as shown in dashed lines, one District heating supply device 34.

In the case of these variants described, the vapor pressure which is set can be lower than the drum pressure, which is advantageously a deeper one Rust surface temperature.

Finally, it is according to the further embodiment variant shown in FIG. 6 the invention also possible, the manifold 30 in a steam separator 35th lead so that the water / steam mixture gets into the steam separator, the separated steam then into the drum 28 of the boiler 3 lead and the remaining saturated water into the feed water tank 24 attributable, thereby additionally the cooling water 15 via a Heat exchanger 37 can be preheated.

It is also advantageous if the water supply line 16 to a moving Grid lining unit row 10.3 leads, this via a flexible connecting line 38 is connected to a fixed grating unit row 10.2 and the Discharge line 17 from the fixed grate lining unit row 10.2 to Bus line 30 leads. In this case, the discharge line 17 can have a larger diameter, since it does not have to be flexible and that in it contained water / steam mixture creates only a small pressure drop.

Of course, the invention is not limited to that described Embodiments limited.

Reference list

1

rust

2nd

Firebox

3rd

Waste heat boiler

4th

Empty train

5

Bundle train

6

Firing material, solids (waste)

7

Primary air

8th

Secondary air

9

Flue gases

10th

Grid lining unit series

11

Rust covering unit, e.g. B. grate bar, grate plate

12th

Side wall

13

Middle bar

14

Cooling channel in pos. 11, 12, 13

15

cooling water

16

Supply line to item 14

17th

Discharge line from item 14

18th

Expansion circle

19th

Three-way valve

20th

Pressure drop point, e.g. B. throttle valve, orifice, thin tube

21

Line for item 15, branched off from item 22

22

Feed water pipe

23

Feed water

24th

Feed water tank

25th

Feed water pump

26

Feed water control valve

27

Economiser

28

Drum (customer)

29

check valve

30th

Manifold

31

Evaporator

32

Superheater

33

Water injection

34

District heating supply facility

35

Steam trap

36

Injector

37

Heat exchanger

38

flexible connecting line

TCA

Temperature control system

Claims (14)

Method for cooling a grate (1) for a combustion chamber (2) by means of Water (15), with a waste heat boiler (3) downstream of the combustion chamber (2) is connected downstream via a feed water line (22) Feed water pump (25) and feed water control valve (26) feed water (23) is supplied, and the grate (1) consists essentially of several in rows (10) juxtaposed grate covering units (11) and side walls (12) and possibly middle bar (13) and crashes, within which the cooling water (15) is guided along in cooling channels (14), thereby characterized in that part of the feed water (23) after the Feed water pump (25) and before the feed water control valve (26) from the Feed water line (22) removed and via at least one Pressure drop point (20) is passed and then as cooling water (15) Cooling channels (14) is supplied, the cooling water (15) at Flow through the cooling channels (14) at least close to Saturated steam temperature is heated and then a consumer (24, 27, 28, 34, 35) is supplied. A method according to claim 1, characterized in that the cooling water (15) heated to saturated steam when flowing through the cooling channels (14) is and thus part of the cooling water (15) is evaporated. A method according to claim 1 or 2, characterized in that the heated cooling water or cooling water / steam mixture of the drum (28) of the Waste heat boiler (3) is supplied. A method according to claim 1 or 2, characterized in that the heated cooling water or cooling water / steam mixture part of the Steam network is supplied, in which the pressure is lower than that Drum pressure is. A method according to claim 2, characterized in that the Cooling water / steam mixture is fed to a steam separator (35) separated steam is passed into the drum (28) and that remaining saturated water is returned to the feed water tank (24) becomes. Method according to one of claims 1 to 5, characterized in that a pressure drop in the cooling water in the at least one pressure drop point (20) (15) is generated, which is at least ¼ of the pressure drop between the Leaving the feed water pump (25) and entering the consumer (24, 27, 28, 34, 35). Grate (1) for the combustion of solids (6), which according to the method is cooled according to one of claims 1 to 6, wherein the grate (1) in essentially of several arranged in rows (10) side by side Grate covering units (11) and side walls (12) and optionally Center bar (13) and crashes, each with cooling channels arranged therein (14) for the application of cooling water (15) and from supply (16) and Discharge lines (17) and flexible connecting lines (38) for the Cooling channels (14), and the grate (1) a waste heat boiler (3) is connected downstream via a feed water line (22) Feed water pump (25) and feed water control valve (26) feed water (23) can be supplied, characterized in that the cooling channels (14) one have a comparatively small inner diameter, the maximum Size is designed so that no separation of water and steam takes place, and that the lines (16, 17, 38) to the cooling channels (14), which in moving grate lining units (11) are, pipes are with one Inner diameter, which is smaller than the inner diameter of the Cooling channels (14), and wherein the supply lines (16) between Feed water pump (25) and feed water control valve (26) with the Feed water line (22) are connected and in the supply lines (16) at least one pressure drop point (20) is arranged. Grate according to claim 7, characterized in that the pressure drop points (20) Apertures are. Grate according to claim 7, characterized in that the pressure drop points (20) are thin tubes. Grate according to claim 7, characterized in that the pressure drop points (20) are throttle valves. Grate according to claim 7, characterized in that the cooling channels (14) cast pipe coils are. Grate according to claim 7, characterized in that the Zu- (16) and Drainage lines (17) for the cooling water (15) with at least one Expansion circle (18) are executed. Grate according to claim 7, characterized in that several parallel Subsystems of the cooling system are present, the number of which thermal load of the parts to be cooled is dependent. Grate according to claim 7, characterized in that the feed line (16) the cooling water (14) with a moving grate lining unit row (10.3) is connected, which in turn via a flexible connecting line (38) a fixed row of grate pads (10.2) is connected.

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