DD260412A3 - METHOD FOR ACCESSING A CARBON STEAM GENERATOR - Google Patents

Abstract

The invention relates to a method for starting a coal dust-fired steam generator, wherein the zuendfaehige coal dust is generated at the same time and should be made available to be approached steam generator. This is achieved in that a run as Anfahrmuehle operating pulverized coal of the approaching steam generator started, the pulverized coal Teilstroeme via controllable cross-connections in an in-service steam generator and the Anfahrmuehle is driven stable, and that then according to the Anfahrregime the steam generator to be approached the Kohlenstaubteilstroeme the Anfahrmuehle is gradually promoted in the steam generator to be approached. Fig. 1

Description

For this 3 pages drawings

Field of application of the invention

The invention relates to a method for starting a pulverized coal-fired steam generator, wherein the pulverized coal conveying gas mixture is produced with operating pulverized coal mills and coal dust sub-lines to partial burners of pulverized coal main burners, and that for starting with a pulverized coal Anfahrmühle a coal dust conveying gas Generated mixture and is promoted in the steam generator to be approached.

Characteristic of the known technical solutions

For the start of coal dust-fired steam generators, the use of coal dust and also the use of coal dust is known. A disadvantage of pulverized coal pilot burner systems is that the coal dust must be bunkered for a long time or is deposited on an operating adjacent steam generator from the mill system and is blown over Zündstaubquerverbindungsleitungen on approaching steam generator via pilot burner.

Characteristic of all these solutions is also that the coal dust is diverted as a partial flow from a mill system and bunkered or driven in through traffic to the neighboring steam generator. This is necessary because the Ventiiatormühleleistung is a multiple of the heat output of a pilot burner.

Again, it is also not possible to approach the mills in a cold steam generator and operate with hot flue gases, since the hot flue gases or the hot air are not available to a cold steam generator. For this solution has been proposed to bring hot fumes via the flue gas recirculation of an adjacent steam generator by means of a cross-connection to the mill system of a steam generator to be approached or suck, then to take this mill very early in operation. In this solution, although the hot flue gases lead to the earlier commissioning of the fan mill or hot flue gases lead to start a mill, but then it is not possible in the startup process to burn the coal dust generated in the mill systems to main or Zündbrennern.

The reason for this is the high minimum power that can be driven with a mill, so that the dust discharge behavior with minimum conveying speed is ensured in the classifier and pulverized coal pipes. Too low dust loads at large quantities of conveying gas also prevent in these solutions, an ignition-stable mixture of a main burner.

The total heat output of the fan mill continues to exceed the gradual heat input necessary in the steam generator and thus the start-up gradient of the water-steam system.

The above-mentioned technical solutions have the following disadvantages:

For stocked Zündstaub correspondingly large bunkers must be present, which are placed in the boiler house or outside the boiler house. These must be able to absorb the coal dust for at least one start-up process.

Large investment costs for steel construction, bunkers and pipes are necessary. For starting by means of direct traffic generated by neighboring steam generators and diverted from mills Zündstaub to be approached steam generator Kohlenstaubzündbrennern correspondingly long Zündstaubleitungen are required, which must be supplied with large fan for pneumatic delivery or which in Ejektorzündbrennern (steam-powered vacuum generation at the burner) high steam consumption or Preßluftverbräuche need to generate the negative pressure and thus the ignition is deteriorated in the burner area and the Zündbereitschaft is not present. In addition, only limited amounts of dust and thus burner performance can be realized over long Zündstaubleitungen.

It is known to grind separately via additional starting mills raw lignite coal or hard coal to ignite and operate from there via Zündstaubleitungen the pilot burner of a steam generator. This has the disadvantage that an additional mill with the associated piping systems must be installed.

In addition, it must also be ensured in this system via intermediate bunkers that the minimum mill performance of this additional mill is intercepted in the first phase of the startup, because the Zündbrennerleistung yes only gradually from zero to the maximum load may be raised.

Furthermore, it is known to approach via Rauchgasrücksaug transverse connections a fan mill to be approached steam generator with cold steam generator.

It is also known that fan mills can work directly to the main burner system of adjacent mills via cross connections in the pulverized coal pipes.

Both solutions have the disadvantage that the complete coal or dust power of a fan mill are blown into the steam boiler to be approached for starting up.

Even with fan mills firing the goal is to take part burner of the main burner system with switched off other part burners of a mill system individually in order to operate these individual part burners as Kohlenstaubzündbrenner.

Object of the invention

The aim of the invention is to approach a steam generator to be supplied in the cold state without coal dust stable.

Explanation of the essence of the invention

The invention has for its object to produce the coal dust at the same time and to provide the steam generator to be approached.

This is achieved in that according to the invention operated as Anfahrmühle operating coal dust mill approached the steam generator, the coal dust partial flows promoted via controllable cross-connections in an operating steam generator and the Anfahrmühle is driven stable and that thereafter according to the Anfahrregime the steam generator to be approached the coal dust Partial flows of the Anfahrmühle is gradually promoted in the steam generator to be approached.

embodiment

Reference to an embodiment of the invention will be explained in more detail. The drawings show:

Fig. 1: the arrangement of Anfahrmühlen coupled with dust collectors and the cross connections between adjacent steam generators in principle;

Fig. 2: the integration of the separator of the Anfahrmühle on the steam generator in principle; Fig. 3: the arrangement of the cross connections with the circuit options between adjacent mills of adjacent steam generators in principle.

Two adjacent steam generators A; B have the combustion chambers 19 (Fig. 1). At the combustion chambers 19 are the mills C on the steam generator A; D; e; F installed. At the steam generator B, the mills are C; D; e; F installed. The mills are connected to the coal feed 28 and to the conveying gas line 29 designed as a collecting line. The conveying gas manifolds 29 are connected via the hot air transverse connection 20. The mills are connected to the main burners 17 via pulverized coal mains 30, dust distributors 26 and main burner stacks 18. The main burner dust pipes 18.1... 18.5 are arranged downstream of the dust distributors 26 per mill and lead into five main burners 17.1... 17.5, which are arranged in a plane of the combustion chamber 19. On the steam generator A are located in the main burner overhead lines 18.1 C ... 18.5 D, the dust diverter 1.1 A ...- 1.5 A, which are connected via the dust lines 2.1 ... 2.5 with the separators 3.1 ... 3.5.

At the steam generator B, the branch flap 1 B is arranged in the coal dust main 3OE, which is connected via the branch line 31 with the dust manifold 27 to which via the dust lines 2.1 ... 2.5 also the associated separator 3.1 ... 3.5 are connected. Below the separators 3.1 ... 3.5 are pressure-resistant slide 8.1 ... 8.5 and the trigger devices 7.1 ... 7.5 (Fig.2). These draw-off devices 7.1 ... 7.5 are on both sides by the pressure-resistant slide 14.1 ... 14.5; 15.1 ... 15.5 designed lockable and open on the slide side 14 via Zündstaubleitungen 9.1 ... 9.5 in the Ejektorbrenner 10.1 ... 10.5, which have the steam pipes 11.1 ... 11.5. The pressure-resistant slide 15.1 ... 15.5 both steam generator A; B are connected via interconnections 13.1 ... 13.5 according to their assignment. The exhaust air ducts 4.1 ... 4.5 of the separators 3.1 ... 3.5 are connected to the secondary air part of the ejector burners 10.1 ... 10.5 via the pressure-resistant slides 5.1 ... 5.5 and via the exhaust hoods 6.1 ... 6.5

 The mode of action is explained by means of various operating cases:

1. starting process

If the steam generator A is started, the steam generator B must be in operation. The hot air transverse connection 20 is opened. The conveying gas line 29 A is between the mills D; C of the steam generator A shut off, so that only the mill D is flowed through by the hot air cross-20 with hot air.

The starting mill D from the steam generator A is ready for operation.

Dampers 1.1 A ... 1.5A and sliders 5.1 A ... 5.5A; 8.1A ... 8.5A; 15.1 A ... 15.5A; 15.1 B ... 15.5B; 14.1 B ... 14.5B and the steam pipe 11.1 B ... 11.5B to the ejector burners 10.1 B ... 10.5B are opened. The sliders 14.1 A ... 14.5A; 8.1 B ... 8.5B are closed. The starting mill D of the steam generator A is put into operation and charged with minimum amount of coal. The pulverized coal is separated by dust diverters 1.1 A ... 1.5 A, separators 3.1 A ... 3.5 A, draw-off devices 7.1 A ... 7.5 A, cross-connections 13.1 ... 13.5, draw-off devices 7.1 B ... 7.5 B to the ejector burners 10.1 B ... 10.5B sucked and blown into the hot combustion chamber 19 of the steam generator B. The operation management is automatically carried out and checked by means of the function group circuit "start-up readiness." The ejector burners 10.1 A ... 10.5A are then ready for operation located automatically or manually controlled balanced mill.

The exhaust air blown in via the separators 3.1 A ... 3.5A, the exhaust air ducts 4.1 A ... 4.5A via the out-of-operation ejector burners 10.1 A ... 10.5A at their secondary air box has a low residual dust proportion corresponding to the separation efficiency (approx %). These dust contents of about 0.012 gr / m ³ are well below the minimum ignition limits of mixtures. Even their absolute amount, as unburned dust content, is far below the quantity of unburned material produced when the dust burners are switched on and carried along in the flue gas stream. They are mostly deposited in the E-filter.

After the "start-up readiness", the ejector burners 10.1 A ... 10,5A can be put into operation in any desired sequence and time duration, after the connection of an ejector burner 10, its electrical ignition device and steam line 11A are put into operation and then the assigned slide 14A opened and the slide 15A, 15B and the steam line 11 B closed.

It is possible to control the ejector burners 10 in their fuel flow rate. This is done via the suction of the ejector burner by adjusting the steam supply and also via the change in the coal feed to the mill. At the same time, different burner outputs can be set at the same time. The separation efficiency at the separators is automatically controlled by the independent adjustment of the filling level in the separator. A monitoring of the amount of conveying air to the starting mill D protects them from spilling.

It will also be possible, after a certain Anwärmzustand the mill D of the steam generator A via the closing of dust 1 single main burner in operation. For example, after operation, the ejector burners 10.4A; 10.2A the switch 1.3 is closed and the main burner 17.3 is put into operation, if appropriate ignition safety is ensured.

It is also possible, prior to the ignition of the Ejektorbrenner 10 during cold start operation via the hot air cross-connection 20 and the starting mill D of the steam generator A with cold air from the primary fan mixed hot air to blow the main burners 17 or ejector burners 10 in the combustion chamber 19 to preheat them.

2. Minimum load and support burner operation

The ignition stability at partial load, minimum technical load and holding operation of the steam boiler can be largely secured by the Ejektorbrenner 10. For these cases z. For example, for the steam boiler A, the pulverized coal of the starting mill D has been driven completely onto the ejector burners 10.1 A ... 10.5 A via the dust compartments 1.1 ... 1.5. The switching operations are carried out automatically via the "auxiliary burner operation" function group, thus ensuring a boiler output of 25%, but it is also possible to ensure the partial load of the steam boiler in the event of a shortage of coal or other disruptions over long periods of time.

3. Start in the event of failure of your own starting mill

If the steam boiler A is started and the own starting mill D or the hot air transverse connection 20 is not ready for operation, then the commissioning of the ejector burners 10.1 A ... 10.5A takes place via the starting mill E of the adjacent steam generator B. In this case, after switching " Supporting burner operation "on the steam boiler B in operation, the individual ejector burners 10.1 A ... 10.5A are connected with their cross connections 13.1 ... 13.5

the cold combustion chamber 19A must be expected with high steam consumption and additional ignition aids. It is also possible to take secondary air from the lower part of the main burner 17E for this ejector burner operation or to use the air in the combustion chamber 19 for combustion.

Of course, the variants shown are arbitrarily coupled together. In particular, it is possible to dispense with the hot air cross-connection 20 or to take it out of operation at the appropriate preheating state of the conveying gas line 29 (FIG. It is also possible, with relatively dry coals, in particular hard coal, to take the mills with cold conveying gases from the line 29 into operation.

By promoting a highly dust-laden conveying gas-dust mixture via the cross connections 13 {Fig. 1), these lines need only have a relatively small diameter, so that even over existing support structures, the wiring is to be realized.

A special case of operation exists if the mills are designed as fan mills and thus the conveying gas line 29 (FIG. 1, 2) is replaced by flue gas back suction 32 (FIG. In this case, to start the mill D from the steam generator A of a flue gas transverse connection 40 (FIG. 3) or a hot gas generator 39 must supply the starting mill D with hot conveying gases for the treatment of the fuel. In this case, flue gas is used as the conveying gas via the pulverized coal main pipe 30 (FIGS. 1 and 2).

To this as completely as possible to keep away from the Ejektorbrennern 10, the coal supply to the Zündstaubleitung 9 and cross connection 13 via the slide position 8 is dimensioned so that a constant amount of dust is stored in the separator 3, which connects the Rauchgasabsaugung from the separator 3 to Ejektorbrenner 10. In this case, again a dust-rich conveying gas congestion b mixture is produced with ambient air and promoted to Ejektorbrener 10 via Luftansaugöffnungen in the extraction device.

For the operating case that the Zündstaubleitungen 10 and cross connections 13 are operated with pneumatic pressure boosting (eg, when operating with ignition vortex burners), the slider 8 is replaced by a cell wheel as an arbiter. This is followed by a distributor, which optionally gives up on the Zündstaubleitung 10 or cross connection 13 the dust. Both delivery lines must be operated with fans or other compressed air generators. Again, the flue gas or conveying gas is separated from the dust in the separator.

Of course, this operating case can also be coupled with the variants already described (FIG. 1, 2). The steam generator A with the starting mill E and the adjacent steam generator B with the starting mill D have the four main part burner 17.1 ... 17.4, which with the mills E; D via the coal dust main pipe 30 with the mill shifter 37; 38 and the dust distributor 26 and the dust lines 2.1 ... 2.4 are connected (Figure 3). From the combustion chamber 19, the flue gas recirculation 32 is branched off, which in the suction side of the mills E; D opens. In the flue gas recirculation, the coal feed opens 28th

In addition, for coupling the mill systems E; D the sliders 33.1 ... 33.3; 34.1 ... 34.3; 35.1 ... 35.3 arranged. Between the branches of the dust lines 2.1 ... 2.3 of the steam generator A; B are connected via the slide 33.1 ... 33.3 the cross connections 13.1 ... 13.3.

In a further embodiment, either the flue gas transverse connection 40 with the necessary slides 5; 14; 15 or the transverse connection 36 with the mill slides 37; 38 arranged.

Furthermore, the cross connections are 13.1 ... 13.3 replaced by the cross connections 41.1 ... 41.3, which branch off from the dust lines 2.1 ... 2.3 and open via the slide 33.1 ... 33.3 of the mill D in the flue gas recirculation 32 of the mill E. , Again, it is possible, the cross-connection 36 with the mill slides 37; 38 to install. According to the requirements is z. B. to the main part burners 17.4, through which the first commissioning of the burner takes place, arranged an electric ignition device 12 or another ignition device. The mode of action is described by means of different variants, variant 1

As cross connection only the cross connections 13.1 ... 13.3 are installed. The following circuit state is established: The steam generator Aistin operation, the steam generator B sol I are approached. The sliders 34.1 A ... 34.3 A are closed. The slides 35.1 A ... 35.3 A; 33.1 A ... 33.3Are opened. The mill E is out of order. The sliders 33.1 B ... 33.3B; 34.1 B ... 34.3B are opened. The slides 35.1 B ... 35.3B are closed. The mill D is put into operation after a certain warm-up time of the steam generator B, that is, via the flue gas recirculation 32 B warm flue gases are sucked. This can be done after a warm-up of the steam generator B. But it is also possible that over hot gas generator or Zündbrennkammern 39, the flue gas recirculation, z. B. is also heated by Kohlenstaubzündbrenneranlagen.

The coal feed 28 B goes into operation. In the fan mill D, the conveying gas-dust mixture is treated and pressed through the coal dust main line 30 and the Staubverteiier26in the dust lines 2.1 B ... 2.4B. When the electric ignition device 12 is in operation, the partial main burner 17.4 is put into operation and stably ignited by the mill Teilommand of the conveying gas-pulverized coal mixture, while the remaining part streams of the conveying gas-dust mixture via the slide system 33; 34; 35 is deflected and is conveyed via the cross connections 13.1 ... 13.3 to the adjacent burner system of the mill E of the steam generator A and is blown on the main burner 17.1 A ... 17.3 A at the neighboring steam boiler.

According to the necessary warming up condition of the combustion chamber 19B are optionally on the slide 33; 34; 35 cross connections 13.1 ... 13.3 switched off, in order to put the partial main burners 17.1 ... 17.3 B into operation. Variant 2

It is additionally the flue gas transverse connection 40 with the sliders 5; 14; 15 installed.

As a supplement to variant 1, the flue gas transverse connection 40 can go into operation when the heating chamber 19B is low, or in the absence of the hot gas generator 39, the slides 15A; 5 A; 5B; 14 B are opened and the slides 14 A; 15B to be closed. This is sucked on the flue gas recirculation 32 A, the flue gas transverse connection 40 and the flue gas Rücksaugung 32 B hot flue gas from the steam generator A. The further operation is carried out as in variant 1

Variant 3 The cross connections 41.1 ... 41.3 are installed as cross connections. The following circuit state is established: The

Steam generator A is in operation, the steam generator B is to be put into operation. The mill E is in operation, all four partial main burners 17.1 A ... 17.4As are in operation. The mill D of the cold steam generator B should be approached. The slides 35.1 B ... 35.3B are closed, the slides 33.1 B ... 33.3B are open. (The slides 34.1 ... 34.3 can be omitted.) After a certain warm-up time of the flue gas recirculation 32 B hot gas generator 39 or preheated combustion chamber 19B or via the operation described in Variant 2 with flue gas transverse connection 40, the coal feed 28B is put into operation with mill D in operation The pulverized coal conveying gas mixture of the pulverized coal main pipe 30 is now stably ignited with partial flow via the main burner 17.4B and the electric igniter 12 in the combustion chamber 19B to be approached, while the remaining conveying gas dust quantities via the open slide 33.1 B ... 33.3B and the cross connections 41.1 ... 41.3 into the flue gas return 32Abzw. be sucked into the mill door or the mill entrance of the mill E. The mill E in operation will thereby reduce its own intake of hot flue gas volume from the flue gas return 32A. This can also be enhanced by partially closing the slider 14A or other throttle device. Also a reduction of the coal supply 28 A is possible.

The produced in the mill D Fördergasstaubstrom is fed through the mill E again, further processed the dust and injected via the coal dust main 3OA, the dust lines 2.1 A ... 2.4A and the main burner 17.1 A ... 17.4A in the combustion chamber 19 A. and burned there.

In variant 3, the advantage over variant 1 and 2 is that on the suction power of the mill E an additional suction effect of Fördergasstaubgemische from the dust lines 2.1 ... 2.3 B takes place and thus the risk of dust deposits in the cross-connection and the reduction of the delivery gas quantities the associated lower speeds in the cross-connection compared to the speeds in the dust line 2.4B, which leads to its own burner, is avoided.

In this solution as well, the shutdown of cross connections 41 will now be carried out in favor of the commissioning of partial main burners 17.1 B ... 17.3B. In this case, the ignition of the further pulverized coal flames 17.1 B ... 17.3B can preferably take place via the partial main burner 17.4 already provided with ignition aids (electrical 'ignition device) with its stable flame.

When installed flue gas transverse connection 40 but all slides 5a; 15A; 14A; 5B; 14B; 15B to be opened so that either optionally flue gases from the steam generator B or the steam generator A can be sucked.

Variant 4

In addition to the cross connections 41.1 ..141.3 is the cross-connection 36 with the mill slides 37; 38 installed.

The following circuit state is produced when starting the steam generator B and in operation steam generator A: The mill shifter 37; 38 are closed, the cross-connection 41.1 ... 41.3 is ready for operation. Both mills E; D are put into operation at the same time. This hot hot gases are sucked in via the flue gas Rücksaugaugung 32A and through the mill E, the cross-connection 36, the mill D, the coal dust main 30 partially blown into the main burner 17.4 and sucked back through the cross connections 14.1 ... 14.3 in the flue gas Rücksaugung 32 A. After a certain Anwärmzustand both mill systems, the coal feed 28 A is put into operation and thus generated in the mill E ignitable Fördergasstaubgemisch which completely conveyed via the cross-connection 36 to the mill D, where again completely ground and processed through the coal dust main 30 and the dust manifold 26 as Partial flow is blown on the main burner 17.4B, there stably ignited and burned and the remaining part streams are sucked back to the mill E via the cross-connection 41.1 ... 41.3.

The cooling supply 28 A is greatly throttled, since practically about 75% of Fördergasstaubgemisches in circulation between the mills E; D is driven.

This variant has the advantage that without flue gas cross-connection 40 and without a warm-up of the steam generator B or without hot gas generator 39, the fan mill D approached from the cold state, completely put into operation with minimal load or normal load and doing an extremely ground and thus ignitable mixture on Teilhauptbrenner 17.4 is ignited.

Also in this variant, according to the preheating and warming up of the combustion chamber 19 B, a shutdown of the cross connections 41.1 ... 41.3 in favor of the commissioning of partial main burners 17.1 B ... 17.3B performed.

Variant 5:

The cross connections 36 and the cross connections 13.1 ... 13.3 are installed.

The circuit state of the slide is such that by series connection of the mills E; D, which are put into operation at the same time, hot flue gases via the flue gas recirculation 32 and coal 28 A ei η conveying gas mixture from mill E via the cross-connection 36 with closed mill shifter 37 A; 38 B to mill D, where it is ground again and processed via the coal dust main line 3OB blown as a partial flow at the main burner 17.4B and ignited by ignition and the remaining partial flows of Fördergasstaubgemisches via the cross connections 13.1 ... 13.3 and the sub-main burner 17.1 A ... 17.3A is injected into the combustion chamber 19A.

This variant has the advantage that also through the series connection the conveying gas dust mixture is ground to a maximum and prepared and thus prepared for ignition in the cold combustion chamber 19B. At the same time, there is the advantage, compared to variant 4, that only one transverse connection 13.1... 13.3 is necessary, whereas when installing the transverse connection 41.1... 41.3, two transverse connections 41...

In particular, the variants without greater cross-connection 36; 40 ensure that low Fördergasstaubmengen be promoted as subsets through these cross-connections and thus small pipe diameter with the possibility of execution as pressure-resistant piping can be installed. Thus, the explosion safety is ensured by the compressive strength for the cross-connections with the risk of deposits.

In summary, the following effects are achieved:

A start-up mill working on the steam generator delivers highly enriched pulverized coal conveying gas mixture to coal pulverized coal burners in parallel according to their grinding performance.

The performance of the Kohlenstaubzündbrenner depends on the number of necessary Zündbrenner and after the performance of the so-called Anfahrmühle. In this case, the entire Fördergasstaubstrom the mill is not passed to the existing main burner system, but via branch lines to dust cyclones, which are connected upstream of an underlying Zündstaubleitungs Zündbrennersystem. The exhaust gas from the cyclone is optionally introduced into the steam generator to be approached or into an adjacent steam generator.

Thus, when starting according to the minimum mill performance and the number of pilot burner all these pilot burns by switching on the Anfahrmühle at the same time go into operation and thus the heat of combustion is supplied to the steam generator (which would lead to driving over the Anfahrgradienten), is the beginning of commissioning of Anfahrmühle about ignition dust-side cross-connections below the cyclones between adjacent. .

Steam generator systems of the ignition dust from all cyclones of the Anfahrmühle promoted via the cross connection directly to pilot burners of the adjacent steam generator and blown there into the already in operation steam generator. This heat supply in the operating in-line steam generator is not a problem, since this is already in operation with a considerable heat and the additional heat only leads to a small gradient change or the automatic control, the heat output of their own mills is reduced according to the increased heat through the cross connection.

In the first phase of the starting process, therefore, the entire amount of pulverized coal of the Anfahrmühlein the cyclones switched on and injected via the associated cross-connections to the pilot burners of the adjacent operating steam generator. Only when this operation is stable, according to the existing start-up regime, the operation of the pilot burner of its own steam generator to be approached. Now, depending on your needs, the cross-connections can be blocked in favor of commissioning your own pulverized coal firing burner.

It is thus possible to take one after the other in arbitrary periods, the pilot burner of the steam generator to be started in operation and to supply as partial flow of the starting mill with ignition dust. At the end of the connection of all pilot burner of the approaching steam generator, the Anfahrmühle can still work with a minimum allowable load and then increase the performance of the AnfahrmühIe the performance of Kohlenstaubzündbrenner evenly to maximum mill performance. It is also possible thereafter to uniformly vary the performance of the pilot burners in accordance with mill performance. It is advantageous that the ignition of the approaching steam generator and the combined ignition-delivery system is designed only on the Zündstaubleitung from its own separator to its own pilot burner and must ignite optimally for this distance, while the cross connection to the neighboring steam generator with the associated larger Luftfördergasmengen or the amount of steam necessary for a Saugbrenner for sucking the pulverized coal gas mixture to ignition difficulties on the adjacent steam generator and its pilot burners may result.

However, this is not a problem, since ever this steam generator is in operation and stable burning, so that the coal dust does not have to ignite the burner, but it is sufficient if it is blown only in the steam generator, since it can burn there by the stable fire. Thus, there is the advantage that the pilot burner only has to optimally design the short line piece from the separator to the burner of the steam generator to be approached, while the long conveyor lines with additional energy required for the secondary steam generator do not simultaneously have to require a stable ignition at this adjacent coal dust burner.

Of course, it is also possible to direct ignition dust lines without ignition separator or main burners of the own steam generator and via cross connection to ignition or main burners of the adjacent steam generator and produce similar Umschaltmaßnahmen parts of the dust-conveying gas mixture of the mill in the production of a stable mixture from the fan mill To lead neighboring steam generator, in order to obtain lower heat output in the ignition at the directly-blown pilot burners or main burners of their own Anfahrmühle.

After the distribution of the pulverized coal main line in several dust lines, which lead to the partial burners, they are shut off and connectable via cross connections with the main part burners of a fan mill burner system of the adjacent steam generator. In this case, the deducted from the approaching steam generator coal dust-flue gas mixture of a locked-off pulverized coal main burner can be initiated via cross-connections to the opposite main burner part or in the flue gas recirculation of the adjacent mill system of an operating steam generator. In both cases, it is ensured that the cold mill to be approached at the approaching cold mill is completely charged with conveying gas-dust mixture, d. h., That their load can be so large that the reliability in terms of gas production and dust extraction is secured in the channels and in the operation of the burner classifier system.

By branching off a large portion of the conveying gas-stagnation mixture, e.g. 75% or less, it can be ensured that for starting up in the cold steam generator only a small amount of Zündstaubmenge is retracted and ignited at a part burner with relatively small power. This system can be optionally coupled with a flue gas side cross connection. But it is also possible to connect both adjacent fan mills via a dust-side cross-connection in series

The invention achieves the following advantages:

1. It is possible to operate with an installed on the steam generator Betriebsmühle Kohlenstaubzündbrenner or Teilhauptbrenner as Kohlenstaubzündbrenner.

2. It is possible to inject at startup of the steam generator despite commissioning a complete plant mill only small amounts of coal dust as Zündstaub heat output of ignition or partial burners in the combustion chamber and gradually increase or discontinue according to the number of part burner or pilot burner.

2. It is possible to use only one mill for starting the steam generator.

4. Only the minimum amounts of coal dust are conveyed to the adjacent steam generator during a starting process, since the cross connections are switched off stepwise in accordance with the increasing heat input of the steam generator to be approached. This minimizes the delivery energy over longer distances to the neighboring steam generator.

5. It is conveyed mainly Fördergas dust mixture to the neighboring steam generator and thus achieved in particular at high dust loading below Abscheidebunkern minimizing the delivery energy.

6. It is possible to operate the pulverized coal main burners as pilot burners. Kohlenstaubzündbrenneranlagen or consuming oil burner systems can be omitted. Heating oil is saved.

7. It eliminates complex Kohlenstaubbunkerungs- and storage facilities, as the coal dust is promoted in direct traffic from the dust-generating mill to the pilot burner.

Claims (9)

1. A method for starting a coal dust-fired steam generator wherein the pulverized coal conveying gas mixture is produced with operating pulverized coal mills and coal dust sub-pipes to partial burners of pulverized coal main burners, and that generates a coal dust conveying gas mixture for starting with a pulverized coal approach mill and the steam generator to be approached is characterized, characterized in that a run as Anfahrmühle operating pulverized coal mill approached the steam generator, the pulverized coal partial flows conveyed via controllable cross-connections in iri operation steam generator and the Anfahrmühle is driven stable, and that thereafter according to Anfahrregime to approach Steam generator, the pulverized coal partial streams of the Anfahrmühle is gradually fed into the steam generator to be approached. 2. The method according to item 1, characterized in that the pulverized coal partial streams passed as a pulverized coal conveying gas mixture through separators and the separated pulverized coal with or without small conveying gas with or without additional medium as a coal dust conveying gas mixture in the approaching and / or is promoted via controllable cross-connections in the operating steam generator. 3. The method according to item 2, characterized in that the pulverized coal partial streams is conveyed as coal dust-conveying gas mixture in the approaching and / or via controllable cross-connections in the steam generator in operation. 4. The method according to item 2, characterized in that the exhaust gas of the separator is conveyed into the secondary air part of pulverized coal burners or in a negative pressure region of the steam generator to be approached. 5. The method according to item 2, characterized in that the pulverized coal Fördergäs mixture promoted by compressed air and / or steam-driven pulverized coal and from a withdrawal device of the separator either to the pulverized coal suction burner of the approaching steam generator or cross connections through the out of service Extraction devices is promoted to the pulverized coal suction burners of the operating steam generator. 6. The method according to item 1, characterized in that the partial streams of the coal dust conveying gas mixture are conveyed to partial burners of the steam generator in operation. 7. The method according to item!, Characterized in that the partial flows of the conveying gas mixture are promoted to the flue gas back suction or suction of an operating coal dust mill operating steam generator. 8. The method according to item 1, characterized in that the coal dust-conveying gas mixture of a starting mill via controllable cross-connections, the Anfahrmühle of the approaching steam generator is promoted. 9. The method according to item 1, characterized in that the partial flows of the pulverized coal conveying gas mixture of a start-up mill in operation are promoted according to Abfahrregime a steam generator to be removed gradually into the steam generator in operation.