DD231108A1 - METHOD FOR ACCESS AND STAGE OPERATION OF A CARBURNING HEATER - Google Patents

Abstract

The invention relates to a method for starting and Stuetzbetrieb a pulverized coal firing, wherein the pulverized coal with low coal duty and low Foerderluftmenge approached and the coal dust-Foerdergas mixture is promoted in a sub-burner of the pulverized coal main burner. It should be a driving style of mill and burner with significantly reduced power but higher Zuendstabilitaet be achieved when cold starting. This is achieved by throttling and securing the pulverized coal / foamer gas mixture in the pulverized coal main duct in a controlled manner before the discharge of dust.

Description

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Title of the invention

Method for start-up and support operation of a pulverized coal firing

Field of application of the invention

The invention relates to a method for starting and support operation of a pulverized coal firing for a coal dust-fired steam generator with fan mill operation and an arrangement for carrying out the method.

Characteristic of the known technical solutions

For starting steam generators with pulverized coal firing usually oil burners are ignited, which preheat the Brennkarajner and the steam generator to a power of ca, 20 40 % .

If the combustion chamber temperature is sufficiently high, the fan blades are switched on and the pulverized coal on the main burners is ignited above the burning oil flame. This method has the disadvantage that very large amounts of oil are consumed. In another method, the oil burners are replaced by pulverized coal pilot burners with associated pulverized coal bunkers or pulverized coal generating plants · In this case, an equivalent amount of firing dust must be provided according to the previous oil burner performance and previous oil burner operation, d. H. be bunkered before the startup process. There must be correspondingly large coal dust pilot burner, which have an equivalent heat output for the previous oil burner.

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Another possibility is to promote generated coal dust from the neighboring steam generator via a neighbor steam generator connection directly to the pulverized coal pilot burners of the steam generator to be approached or via an intermediate bunker; in any case, at the same time produce and burn at the pilot burner.

All of these methods have the following disadvantages: The main pulverized coal burners have equivalent coal dust output corresponding to the number of mills and the steam generator power. This pulverized coal output per main burner system or _# per fan mill is very large and can only be controlled within limits of approx. 50-100 % of the mill output. This output depends on the temperature level in the combustion chamber or on the temperature of the sucked off flue gases this is the necessary maintenance of the temperatures in the mill mystery, in particular the temperatures to mill "which may be driven only within certain limits. In addition, the pulverized coal is relatively coarse in this process. For economic reasons (wear in the mill system) the grinding is designed in such a way that the pulverized coal burns optimally in the full load and part load operation of the fan mill (J with minimum grinding and minimal mill wear.) which ensures ignition through · If the fan mill is loaded with a smaller quantity of fuel during the start-up operation, then the mixture at the burner has too low a fuel density, ie at constant delivery volume of the fan mill, too little fuel is given off, so that ignition of the total mixture occurs too low fuel density is not possible

Again, however, the amount of fuel injected at the burner is still so great that it requires considerable pilot burner powers of the oil or pulverized coal burner when the minimum fuel load required for the design of the aer fan mill. Z. 3. requires a coal dust main burner with

a coal dust capacity of 30-4Ot coal dust an oil burner capacity of about 3 t or a pulverized coal burner power of about 8 t. In connection with the long start-up times, a correspondingly large amount of coal dust is required for pulverized coal pilot burner systems or for pulverized coal pilot burners.

Another disadvantage is that in the large main burner powers when switching on the fan mill or the pulverized coal main burner a very large amount of heat is entered into the combustion chamber (with secure ignition of Hauptbrenner-, flame), so that the strong heat supply by irregularities in the Starting process leads to inadmissible overheating or Vorverdampfungen in the water-steam system, which does not allow the startup of the steam generator.

This is also the reason that with coal dust pilot burner flames or oil burner flames relatively long, the combustion chamber must be reheated and thereby store correspondingly large amounts of coal dust or »are to be driven from the neighboring steam generator to the pulverized coal pilot burners.

It has already been proposed to drive the entire pulverized coal from the fan mill of an operating steam generator to the fan mill or to 2 fan mills of the steam generator to be approached, where it is to be ground again and with the addition of hot or cold air into the mill system as a pure primary mixture to the main burner blow. Here it can be assumed that the power of the main burner is throttled to about »50 % . This method has the following disadvantages:

1 »Additional ducts must be used to couple fan mills of neighboring steam generators. This additional locks are necessary or appropriate coal dust pipes must be installed.

2. The reduced amount of fuel per burner is distributed to all the part burners of the main pulverized coal burner of a mill. This is due to the addition of air to the delivery volume

a reduction in the concentration of the pulverized coal flame, so that the ignition conditions are deteriorated,

3. This solution is expensive and requires appropriate space or »favorable locations of fan mills, which allow the installation of connecting lines.

4. At the same time, the associated fan mills and burner systems of adjacent steam generators must be operational and operational for this process. Disruptions to a mill mean that the system can not be used «

A partial solution for the operation of a fan mill when starting a steam generator with low fuel performance has become known in which a bound to a mill system pulverized coal pilot burner system is operated and that parallel to the main burner system coal dust lines are shut off with a flap or a slider. The coal dust conveying gas mixture is promoted by the higher pressure loss of the still open pulverized coal pipe to a partial burner of a pulverized coal main burner with a larger form and thus also a part of this coal dust conveying gas mixture of pulverized coal pilot burner system and its separator. In this case, a larger amount of dust is deposited per unit time and promoted to pilot burner · Furthermore, it is possible with this method to promote via an additional approach line from the mill system directly to a pilot burner *

The system assumes that cold flue gas is sucked in and the coal is comminuted, but remains relatively moist (lack of heat supply) ·

The described method has the disadvantage; that a high volume flow is maintained to promote the pulverized coal and thus the conveying speed in the pulverized coal channel to mill system remains approximately the same. This in turn means that relatively coarse and moist dust discharged or promoted to pulverized coal pilot burner system and thus no ignition stability is achieved.

Object of the invention

The aim of the invention is to develop a method for start-up and support operation of a steam generator with the aid of small pulverized coal pilot burner systems (small burner output and small bunker volume).

Explanation of the essence of the invention

The invention has for its object to achieve a driving style of fan mill and main burner system with significantly reduced power and a higher Zöndstabilitit when cold starting.

Is this is achieved in that according to the invention d _a s pulverized coal feed gas Geraisch in the pulverized coal main channel controlled from dust line division throttled and spotted · In order to realize the deposited coal dust, the invention bunkered and / or with or without a carrier gas to the part burner in operation of the pulverized coal Main burner or the pulverized coal gas burner or an inlet opening

assigned to the combustion chamber.) Depending on your needs

25% to 75 % of the pulverized coal pipes and Hauptbrenneröffnungen closed by means of flap or slide, so that due to the large pressure loss, which occurs through the transport of the conveying gas through the open part of the pulverized coal burner, the delivery volume extremely throttled * is. The throttling takes place only in the area of the division of the pulverized coal pipes, so that in the area of classifier and also in the area of the common pulverized coal channel no division change takes place until the division. This reduces the conveying speed extremely strongly in this channel area. Due to the lowered conveying speed, a reduced conveying capacity of the pulverized coal occurs when raw lignite is added in accordance with the laws of conveying technology. According to the FRUUDESCHEN model law Fr = w2 / d · g (w conveying speed, d - grain diameter, g - gravitational acceleration) which describes the pneumatic conveying of grain sizes, the conveying speeds for a conveying

of the grain proport ional de r root from the ratio of the diameters: W2 / W1 = * Y dg / d *.

If som.it the conveying speed w ^ of the delivery volume halved by the throttling in the coal dust lines, this means that the max. to be conveyed grain diameter d ₂ to about 70% of the initial diameter d- go back. This means that the mean grain diameter of the grain to be conveyed is greatly reduced. This is achieved by the fact that coarse grain particles can not be conveyed in the coal dust channel according to Sichter up to the region of the coal dust line distribution due to the low conveying speed and fall back into the mill system or into the classifier. There they go back to the mill system via the semolina return and are ground again. Thus, there will be a constant precipitation of coarse dust particles in the coal dust channel with low conveying speed, which leads to the top grinding of coal dust mixture.

embodiment

Reference to exemplary embodiments, the invention is explained in detail. The drawing shows:

1 shows the arrangement of the throttled conveying path in conjunction with a pulverized coal pilot burner system on a combustion chamber,

2: the design of the coal dust duct after mill and before the distribution of dust lines for throttling the conveyor cross-section with flap,

3: the design of the coal dust channel after mill and before the distribution of dust lines for throttling the conveyor cross-section with slider,

4 shows the arrangement of the throttled conveying path in conjunction with a pulverized coal and dust burner system acting on the pulverized coal main burner, including the control thereof,

Fig. 5: the arrangement of the electrical ignition device in the partial burner.

The combustion chamber 13 of an 815 t / h steam generator has the fan mills 1.1; 2.1; 3.1; 4.1; 5.1; 6.1 (Fig. 1). Oie pulverized coal pipes after fan mill divide into two coal dust pipes 1.2; 1.3; 2.2; 2.3; 3.2; 3.3; 4.2; 4.3; 5.2; 5.3; 6.2; 6.3. Here are immediately before the division of the mills 1 ·! 2.1; 3.1; 5.1 slide 1.4; 2.4; 3.4; 5.4 mounted such that each of a coal dust channel 1 * 3; 2.3; 3.3; 5.3 closable and the open © coal dust channel 1.2; 2.2; 3.2; 5.2 is partially closed. Immediately in front of the sliders 1.4; 2.4; 3.4; 5.4 are the branch channels 1.5; 2.5; 3.5; 5.5 to the cyclone bunker systems 1.6; 2.6; 3.6; 5 * 6 attached. In this case, the exhaust gas of the cyclone bunker system 1.6; 2.6; 3.6 via the exhaust pipes 1.8; 2.8; 3.8 in the flue gas recirculation of the mills 1 * 1; 2.1; 3.1 passed and the exhaust of the cyclone bunker system 5.6 introduced via the exhaust pipe 5.8 in the second train 14 of the steam generator in the area after economizer · Below the cyclone bunker systems are Zündstaubleitungen to the pulverized coal pilot burners 1.7; 2.7; 3.7; 5.7 attached. The pulverized coal ignition burners are equipped with electrical ignition devices, eg with electric ignition cassettes or electric ignition lances, depending on the type of choice, which thermocouples and temperature indicators 1.10; 2.10; 3.10; 5.10. These temperature displays are with the Drehzahlverstelleinrichtungen the allocators of the fan mills 1.1; 2.1; 4.1; 5.1 coupled * The fan mills have current consumption indicators, which in the mills 1.1; 2.1; 4.1; 5.1 are also coupled to the Drehzahlverstelleinrichtungen the allocators.

The sifter 15 is connected after the mills 1 via the intermediate piece 16 and mill shifter 29 with the coal dust channel 17 (FIGS. 2 and 3). At the coal dust channel 17, the division of the two pulverized coal pipes 2 closes; 3, which

Divided by intermediate walls 19 in carbon dust fingers to ensure a uniform coal dust distribution to the main pulverized coal burner ~. The flap 13 is housed in the coal dust channel 17 in the recess 20 (Fig. 2) so as not to wear too much in continuous operation and folded state »

In the pulverized coal channel 17, the slide 4 is arranged (FIG. 3), which completely closes the pulverized coal pipe 3 and the pulverized coal pipe 2 partially.

The mode of action is mating:

The steam generator should be started, the bunker 1.6; 2.6; 3.6; 5.6 are filled with pulverized coal (Fig. 1) · The bunker content is z. B. 4 tons of coal dust ·

The electrical ignition devices are put into operation and the pulverized coal pilot burners preheated · After exceeding a prescribed ignition temperature at the temperature indicators 1 * 10; 2 * 10; 3.10; 5.10, coal dust on the coal dust pilot burner 1.7; 2 · 7; 3.7; 5 "7 and stably ignited (eg pilot flame 5 · 9) ·

Above a time relay or manual control, the time is determined, according to which the starting operation of the fan mills and in which order is made when operating pulverized coal pilot burners.

This will be explained using the example of the fan mill 5.1. After a time interval of z. B. 10 min complete and the pulverized coal conduit 5.2 is partially closed with the rail _r about 5.4, the Kohlenstaubleiturig 5.3. Thereafter, the mill 5.1 is put into operation. The hot flue gases of the pilot flame 5.9 are sucked in via the flue gas back suction and the mill 5.1 preheated. The conveying gas temperature will rise to mill 5.1 (temperature measuring point 5.11). After reaching a max. Temperature, the allocator of the mill 5.1 will go into operation with a given allocator speed.

Low flue gas temperatures prevail in the flue gas recirculation. Due to the throttling of the delivery volume only a very low conveying speed is achieved (FIG. 3)

 By throttling on the slide 4 is the cross section

21 of the pulverized coal pipe 3 is complete and the cross section

22 of the pulverized coal pipe 2 partially closed, so that only a free cross section 23 is still available for pulverized coal pipe. Thus, a throttling of the delivery volume is achieved, so that despite increased pressure build-up according to mill 5.1, the speed in the coal dust channel 17 is only about 50 % of the full speed · D. h ·, the low Fördergeschweindigkeit with the flow 24 leads to the precipitation of coarse coal dust 25th

This will take place in particular in the region of the slide 4, since there takes place a deflection or impact of the pulverized coal particles on the slide 4 and the flow 26 enters. This accelerates the precipitation of coarse pulverized coal 25 and the dropping of the pulverized coal into the sifter 15. This pulverized coal 25 falls back into the mill 1 through the classifier 15 and semolina return, is ground again and, with a correspondingly good degree of dusting, is conducted via the flow 24 into the pulverized coal conduit 2. There, the flow rate will approximately correspond to that of the normal operation of the pulverized coal main burners This sighting process in the coal dust channel 17, the pulverized coal is ground extremely fine, has about 5 to S times greater surface area compared to normal operation, is only slightly dried and has high dust moisture · The promotion takes place at high dust densities per amount of conveying gas. That is, compared to the dust-conveying gas mixture of 200 to 300 g / m ^ in normal operation, the amount of dust to 500 to 600 g / ra and further increased · The fine grinding and high dust densities on the main pulverized coal burner cause in the cold combustion chamber 13, the main burner flame 5.12 (FIG. 1) stably burns

and needs to be supported only by a small pulverized coal pilot 5.9.

Is due to the amounts of precipitated coarse coal dust, the dust load and the semolina circulation increase in the mill system such that the max. permissible current consumption I _{mav of} the mill drive is exceeded, the allocator speed will go to O and the fan mills will retract · If the current consumption has fallen back to the value I _ή , the assigner will start up again. This ensures that a max * dust flow is conveyed via the flow 24 to the still open pulverized coal lines 2 and a maximum ignition stability of the main burner flame 5, 12 is ensured. Should the pulverized coal pilot burner 5.7 burn unstably in this mode of operation, or the pilot ignite 5.9, the temperature of the thermocouple 5.10 drops abruptly. This signal is used to immediately take the Mill 5.1 out of order or at least the Zuteilerdrehzahl to 0 scale back _"t If the temperature rises 5.10 back on the firing range, d * h. The pulverized coal firing burner is stably ignited, so according to the specifications after a certain time, the mill 5.1 is put back into operation.

It is also possible to replace the thermocouple 5 × 10 by a flame monitoring system «

If the flap 18 is arranged (FIG. 2), this becomes as far as the channel intermediate wall of the dust lines 2; 3 striking and forming sloping roof leads to increased deflection of the flow 26 with an increased backflow of precipitated coarse coal dust 25 in the recess 20 in the sifter 15 · Here ensures the absence of throttling at the entrance of the flow 24 in the coal dust line 2 Flow rate in the carbon dust fingers formed by the intermediate walls 19 a safe transport of the enriched coal dust mixture.

But it is also possible, the flap 18 to be arranged so that a funnel-shaped inlet channel for pulverized coal pipe 2 ent

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stands. In this case, a homogeneous flow 24 without backflow in the coal dust channel 17 is achieved. The precipitation of coarse coal dust takes place already in the lower channel area. This process is enhanced by dif fusorartige Kanalervveiterung in the region of the intermediate piece 16 or just above. However, the same effect is also achieved if the branch duct 5 (FIG. 2) is guided to the cyclone bunker system 5.6 (FIG. 1) or cyclone (FIG. 4). Then, the homogeneous flow 24 is conveyed over the entire cross section of the coal dust channel 17 and also sucked fine dust in the branch channel 5. In this case, it is possible to integrate the branch channel 5 in the area of the open pulverized coal pipe 2 or in the area of classifier to increase the efficiency of the separation stream 26. Another solution can be used for stable ignition of pulverized coal main burner parts when approaching adjacent steam generator · In this case, the branch channel 5 (Figure 2) directly with a pulverized coal pipe 2; 3 or connected only to a single pulverized coal burner finger 43 (Figure 5) of a mill main burner system of an adjacent steam generator. '· ^: *'. , The increased pressure build-up in front of the flap 18 is used here to blow ignitable fine dust over the main burner parts of the adjacent steam generator and there .A stable ignition flame to produce. Optionally, the used mill-main burner system of the adjacent steam generator can be in or out of operation.

In another solution, the duct 5 (Figure 2) is incorporated into the suction side of the mill main burner system of the adjacent steam generator. When in operation or out of service dispatcher fine dust is supplied, this ground again, then injected with or without dust from the allocator of the adjacent steam generator on the main burner and ignited stable. If the intake of cold flue gases of the adjacent steam generator to be approached is reduced by a slide, only a fine dust conveying gas mixture is sucked in via the branch channel 5. In this case, over hot

or adding cold air in the mill system to be approached, the mixture is enriched with air, eligible for support and capable of being ignited. Again, it is possible that this adjacent mill main burner system is additionally equipped with a flap 18 for foreclosure of a coal dust channel 3 in order to make the advantages already described again take effect.

In the cyclone 6, the branch channel 35 is integrated via the diffuser 30 (FIG. 4). The branch channel 5 opens into the classifier 15 of the fan mill 1 and can be shut off via a pressure-resistant slide 27. At the entrance to the sifter 15, the trigger device 28 is arranged. The pulverized coal channel and classifier 15 is separated by the mill valve 29. The coal dust channel 17 opens via the pulverized coal pipes 2; 3 in the main burner 33. The slider 4 blocks the pulverized coal pipe 3 from. The mill 1 sucks on the flue gas recirculation 31 from the combustion chamber 13 to flue gases and can be shut off by the Rauchgasrücksaugschieber 32 ·

In the cyclone 6, the dip tube 41 is further integrated. The dip tube 41 is connected via the pipe bend 42 with the exhaust pipe 8, - wherein between the dip tube 41 and the exhaust pipe 8, a ratio of the cross-sectional areas of preferably 3: is particularly favorable. The exhaust pipe 8 opens into the flue gas duct of the steam generator, which is located between two heating surfaces. The entry into the flue gas channel is shut off via the pressure-resistant slide 34.

The gas outlet from the cyclone 6 via the exhaust pipe with the pressure-resistant slide 34 into the combustion chamber 13 above the Nachbrennrostes 35. The cyclone 6 is in its outlet with the pressure-resistant cell wheel 36, the outlet opens into the pulverized coal pipe 2, completed. Above the display 11 for the temperature of the mill and the controller 37 is a control via the control line 38 of the drive from the cellular wheel 36 possible. The system is designed by the slide 27 via cyclone 6 to the cellular wheel 26 and slider 34 pressure resistant.

The mode of action is the following:

When starting the fan mill 1, the slide 4 is operated so that the pulverized coal pipe 3 is closed and the Fördervoluraen is promoted only on the pulverized coal pipe 2. In this case, a throttling of the conveyor cross-section and an increase of the pressure in the mill xm classifier 15 and in the coal dust channel 17 occurs · Thus, fine dust is conveyed through the channel 17 due to the lower conveying speed ^ and with increased speed through the coal dust line 2 to partial burner 43 of the pulverized coal main burner 33 is pressed. At the same time, however, pulverized coal conveying gas mixture is conveyed to the cyclone 6 via the draw-off device 28 and the branch line 35. The separated pulverized coal is likewise fed to the partial burner 43 via the cell wheel 36 which is in operation, thus enriching the conveying gas extremely strongly with pulverized coal that the ignition stability is also ensured in the cold combustion chamber 13 · This system can be put into operation so early that the fan cooling system can be switched on earlier than before, even at low flue gas recirculation temperatures and low combustion chamber temperature. For ignition assistance, it is also possible to divide the partial burner into a plurality of pulverized coal fingers and thereby to provide the uppermost pulverized coal finger 43 × 1 of an electrical ignition device, thus securing the ignition of the dusty mixture (FIG. 5).

In this case, the upper air channel 49 can be closed at its burner inlet via a pivotable flap 45. The flap 45 is rigidly connected to the electric ignition cartridge 40, which is pivoted into the burner mouthpiece (pivoting range 47) and with the flap 45 the return stage 45 · 1 forms ·

If, during the start-up of the main burner via the burner finger 43, the high concentration of pulverized coal mixture is injected through the addition of ignition dust via the cellular wheel 36, the following effect occurs

Extending through the barrier of the upper air passage 49 forming recess stage 45.1 into this field for the estimation of particulate matter delivery gas mixture with the formation of a Rezirkulationswirbels 46. Here, the recirculation vortex formed by the heated to above 500 ⁰ C ignition cassette 40 is heated 46 and stably ignited , The oxygen required for this is taken from the conveying gas, which is optionally enriched by adding hot or cold air in the mill system with [oxygen. However, it is also possible, via openings in the flap 45 to add secondary air and / or via openings in the region of the sealing box 48 through the ignition cassette to preheat secondary air into the return step 45.1. In this case, by directional arrangement of the openings this secondary air jet still reinforce the recirculation vortex.

But it is also possible to operate with good fuel, the swivel flap 45 without ignition cartridge 40 and o.g. To achieve ignition effect.

After the mill is transferred to full load, the ignition cartridge 40 is taken out of service and swung back into the sealing box 48, wherein the flap 45 closes the burner mouth.

Of course, the ignition cartridge 40 by any other ignition device, for. B. by a heated electrically or with superheated tube or a retractable and retractable Zundstab or gas or * ölzündbrenner. But it is also possible to replace the cell wheel with a slider and the deposited amount of dust with. allocate small amounts of conveying gas directly to the main burner with the slide open. In continuous operation, it is possible to integrate the cyclone outlet directly via the line 44 above or ^ Lm ignition of the main burner in the combustion chamber and there to introduce dust-rich conveying gas (Fig. 4) and thus temporarily replace the pulverized coal pilot burner.

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In a further embodiment of the invention, it is also possible that a trouser piece is mounted below the cyclone 6, wherein a channel part leads via the cellular wheel 36 to the partial burner 43 and the other channel part of the trouser piece via another cell wheel and the line 44 to the pulverized coal pilot burner 7 leads. Thus, it is also RiOgIiCh ₁ pulverized coal ignition burner 7 during the driving process A _n to operate. But it is also possible to connect an additional bunker with pressure-resistant slide between cyclone 6 and line 44 after the trouser piece to achieve additional storage capacity for the pulverized coal pilot burner 7. In this case, the cyclone bunker system is used to start the steam generator from the cold state with out of service fan mill and only after a certain preheat the combustion chamber 13, the fan cooling system is taken at partially closed slide 4 in operation and the cell wheel 36 for enrichment of the partial burner 43 used. If the bunker reserve for the coal dust pilot burner 7 is used up, a high ignition stability of the partial burners 43 with extremely low steam generator load can be run for a long time without oil insert with several mill systems with closed pulverized coal lines 3 and operating cell wheels 26. But even in continuous operation of the fan mill 1 in the low temperature range to mill 1, ie at high load or, in poor fuel quality, the cyclone bunker system with open slide 27; 34 be connected via the trigger device 28 to the grinding system and the classifier 15. In this case, the cyclone 6 will fill with dust, close in the region of the dip tube 41 and a constant Iriertgassörom is secure through small openings in the dip tube 41 below the cyclone deck, the flow of the cyclone 6 dust ivy. If the fuel calorific value or the ignition stability of the fuel now drops and the mill output must be increased, the temperature in mill 1 (delivery gas temperature 11) drops below the limit value 1 " _M , then an impulse is imparted to the drive of the cellular wheel 36 via the regulator 37 exercised, so that

the cellular wheel 36 goes into operation. Thus, pulverized coal from the cyclone 6 is added to the partial burner 43, and the overall performance of the main pulverized coal burner 33 increases. At the same time, the filling level in the bunker 6 drops, the conveying gas dust is sucked in via the branch channel 5 and a separation takes place. Due to the additional extraction of pulverized coal conveying gas Geraisch from the classifier 15 on the take-off device 28 an increase in performance of the fan mill 1 is achieved * that with open slide 4 a higher Fördervoluraen is enforced by the mill, a larger RQckgesaugte amount of flue gas fed through the flue gas Rücksaugung 31 can be given and therefore also correspondingly more fuel can be given to the mill system via the allocator. By this increase in performance of the fan mill, 1 with simultaneous increase in the delivery volume through the additional extraction at the take-off device 28, the temperature per mill 1 (delivery gas temperature 11) rise again or at the same temperature mill, the amount of fuel can be increased through the meter. In this case, a constant coal dust flow through the cyclone 6 and the cellular wheel 36 is additionally conveyed from the classifier 15 and parallel to the pulverized coal conveying gas mixture, which from the coal dust duct via the pulverized coal pipes 2; 3 and the pulverized coal main burner 33 is additionally added via the partial burner 43 to the main pulverized coal burner 33 via the cellular wheel 36.

The system can also be used for sudden carbon problems and coal interruptions, because then 36 additional coal dust on the burner 33 is offered by the commissioning of the cellular wheel.

The following advantages are achieved:

1. The mill system can remain in operation for any length of time even when the steam generator is starting up, with low burner stability that is stable to ignition or partially switched off main burners »

2. The performance of the oil / gas or coal dust pilot burner supporting the pulverized coal surface is smaller.

3. Less oil, gas or bunkered coal dust is needed to start off «

_t 4 «The bunker output can be smaller or bunkers can be saved.

5. The dust can be separated with less power; Fans are saved.

6. The cyclone bunker system can be pressure-proofed «

7. The mill can produce fine dust; the dust loading can

increase"

S. The mill can be put into operation at a lower gas temperature in good time and also grind extremely moist dust and convey it to the burner.

9 · Mill capacity can be increased, fuel with a lower calorific value can be ground «

Claims (6)

invention claim 1. A method for start-up and support operation of a pulverized coal firing, wherein the pulverized coal mill with low coal output and reduced flow rate and the pulverized coal conveying gas mixture is conveyed in a partial burner of the pulverized coal main burner, characterized in that the coal dust conveying gas Geraisch in the coal dust Main channel controlled by dust line division throttled and sighted, 2, method according to item I _1, characterized in that the throttling of the pulverized coal conveying gas mixture is controlled as a function of the temperature at the pulverized coal main burner, 3 · Method according to item 1, characterized in that the throttling of the pulverized coal conveying gas mixture is controlled as a function of the temperature on a pulverized coal pilot burner » 4, method according to item 1, characterized in that the distributor speed is controlled as a function of the temperature at the pulverized coal main burner or at the pulverized coal pilot burner, ' 1 , 5, method according to item 1, characterized in that the allocator speed is controlled in response to the signal of a flame monitoring device. 6, method according to item I _1, characterized in that the distributor speed is controlled as a function of the current consumption of the fan mill, 7, method according to item 6, characterized in that the separated pulverized coal bunkered and / or with or without conveying gas to the operating part burner of the coal main burner or pulverized coal pilot burners or an inlet opening into the combustion chamber. 8. The method according to item 7, characterized in that the pulverized coal is allocated controlled. 9, method according to item 1, characterized in that a part of the pulverized coal conveying gas mixture is controlled deducted before dust line division and deposited in a separator system fine coal dust · JLOv arrangement for carrying out the method »characterized in that arranged before dust line partitioning the dust lines completely and / or partially shut-off closure device and is designed as a deflection and baffle. ,
·>. , -. 11. Arrangement according to item 7, characterized in that prior to the separation of the dust line, a closable line is integrated into the coal dust channel and / or connected to a dust separator system and / or to a mill main burner system of a neighboring steam generator. 12 «arrangement according to item 7, characterized in that in
the grinder of the mill incorporated a lockable line and / or connected to a dust collector system and / or with a mill main burner system. 13 «arrangement according to item 11 and 12, characterized in that the Staubabscheide system is controllably connected to a partial burner of the pulverized coal main burner«. 14, arrangement according to item 11 and 12, characterized in that the Staubabscheide system is controllably connected to a pulverized coal pilot burner. 15. Arrangement according to item 13, characterized in that the non-isolated partial burner or parts of the partial burner of the pulverized coal main burner has an ignition device. 16. Arrangement according to item 13 or 15, characterized in that the secondary air outlet of the unobstructed partial burner or parts of the partial burner has a return stage forming flap, 17. Arrangement according to item 16, characterized in that the flap has the ignition device. 4 sheets of drawings.