DD156841A1 - SUPPLY AND TREATMENT PLANT FOR BROWN CARBON STEAM FUEL GENERATORS - Google Patents

Abstract

The invention relates to a Zuend- and treatment plant for lignite dust fired steam generators and has the goal to completely eliminate the oil or gas demand previously required in Zuenden and starting and in continuous operation. According to the invention, the coal chute is heated by a pulverized coal-fired auxiliary burner, so that the grinder immediately produces combustible coal dust for ignition, auxiliary and main burners. The safety-approved bunkering conditions are produced according to the invention by a cooling section in the treatment plant and the dust is bunkered in a safe manner.

Description

-ι- 228191 7

Title of the invention Ignition and treatment plant for

brown coal dust-fired steam. producer

Area of application of the invention

The invention relates to a Zünd ~ and treatment plant for lignite-fired DE, in which neither oil nor gas for ignition and continuous operation are required.

It can be used in all steam generators equipped with a pulverized coal combustion plant or where the ignition and treatment plant can be installed as main firing.

Characteristic of known technical solutions

As is well known, before starting up the pulverized coal burners in the steam generator, the combustion chamber is heated by gas or oil fired pilot burners and when the ignition temperature is reached, the burners are ignited by the heat transfer from the combustion chamber to the pulverized coal. In dust firing with gruel humid lignite, the resulting dust is simultaneously pre-dried to the ignitability by sucking back hot flue gases from the firebox into the coal mill.

The gas- or oil-fired pilot burners are constantly in operation until the pulverized coal burners are put into operation and, moreover, for stabilization as a support burner.

 »2 -

In iUeillastfahrweise the steam generator and poor coal quality v / earth also stabilized the dust = flame of the pulverized coal burner, the gas or oil-fired pilot burner as a support burner commissioned ·

There has been no lack of attempts to reduce the high oil and gas consumption required · Thus, it is known to improve the coal dust treatment by an arranged in the flue gas suction oil burner «

Furthermore, attempts have been made to operate the pilot burner and the Zündhilfsbrenner with coal dust, but due to the enormously high cost of additional equipment for commissioning and the unsuitability for continuous operation, the experiment had to be set.

In another known method (WP 120533) a partial stream for bunkering and further use for the operation of the support burner is withdrawn from the dust channel after mill. However, the ignition is still done with oil-fired pilot burner, which remains in operation parallel to the support burner until the required temperature is reached in the combustion chamber to treat the coal dust in the grinding drying system sucked back through flue gases and ignite in the combustion chamber ο

Apart from the still quite substantial oil consumption, the investment is quite large. In addition, additional wastewater charges for fuel oil entering the sewage system of power plants arise in the case of heating oil ignition furnaces.

3 -

2281917

Further disadvantages result from the limited bunker capacity in the boiler room on the one hand and the required amount of ignitable dust for a sufficient operating time of the pilot burner on the other hand and by the maximum bunkering temperature of 60 C on the one hand and the required for safe puncture BrennStaubtemperatur of about 100 - 120 C after Grinder on the other hand.

The expenses required to resolve these contradictions have so far been so high that the Pachwelt has refrained from doing so.

Object of the invention

The object of the invention is to completely eliminate the oil or gas requirement previously required for ignition or starting and stopping as well as in continuous operation.

The essence of the invention

The invention has the object to change the grinding drying system and the process so that regardless of the heat supply from the combustion chamber this approached from the cold state, operated with the generated fuel firing and the coal dust can be bunkered safe technically.

According to the invention, this object is achieved in that the coal shaft shaft durph a coal dust bunker connected coal dust-fired auxiliary burner is heated, that the grinder immediately ignited and ready to burn coal dust and that the grinder including associated sifter on a Brüdentrenner with a coal dust bunker leading , cooled coal dust line is connected ·

It is advantageous to realize this dust cooling by cold delivery air and to arrange the auxiliary burner in front of the mouth of the coal feeder in the coal chute in the associated with this Kauchgasrücksaugleitung ·

To cool the dust generated in the grinder can be done by means of a Brüdentrenners and a dust conveyor exchange the Staubfördermedieη, so that the cold feed air to the dust bunker also serves as a cooling medium. The pilot burner can be fired directly from the divider or from the dust bunker of the auxiliary burner · It is also possible to fire the auxiliary burner with prem dust, eg coal dust from the gas cleaning of the briquette factories or * ready to burn dust from the grinding system of a neighboring boiler possible to dispose of ready-to-burn coal dust · The ignition and treatment plant can also be operated as main combustion ·

The invention will be explained in more detail below on an exemplary embodiment · In the flue gas return line 1, the auxiliary burner 4 is arranged in front of the confluence of the coal feeder 2 in the coal chute 3 and is supplied via the dust line 5 from the dust bin 6 with flammable coal dust »

The coal chute 3 opens into the grinder 7 which is connected on the output side to a separator 8. From the separator, a dust line 9 leads directly to the main burner 10 and a further dust line 11 via a separator 12, a dust conveyor 22 and a dust line 13 to the ignition and support burner From the dust conveyor 22, a further dust line 15 is branched off, which via the cyclone 16 with the dust bunker β

228191 7

connected is. The cyclone 16 is also connected to the combustion chamber via the exhaust air line 20.

The exhaust gases of the Brüdentrenners 12 τ / earth via an exhaust gas conveyor 17 and the line 18 to the combustion chamber · The dust conveyor 22 has a compressed air connection 21 »Via the line 19 kann.Fervemdstaub be supplied or dust. When igniting and starting the steam generator, the grinder 7 is first put into operation and supplied from the dust bin 6 via the dust line 5 of the auxiliary burner 4 with coal dust and ignited. After the grinding system has been heated to the required mill drying temperature by the auxiliary burner 4, the coal feeder 2 is put into operation.

The pilot burner 14 is supplied with combustible coal dust and ignited via the dust line 11, the breaker 12 and the dust line 13. After the pilot burner burns stably, the dust line 9 is opened to the main burner and put into operation. The auxiliary ignition burner 4 remains in operation until the flue gases to be sucked back from the combustion chamber via the flue-gas line 1 have the same temperature as that produced by the auxiliary burner.

In Stützfeuerbetrieb the pilot burner 14 and also the auxiliary burner 4 are taken to the extent required in operation. To secure the required stock of fuel dust, the dust bunker 6 is constantly refilled via the dust line 15 and the cyclone 16.

The necessary for the ignition flammable dust is generated during normal or partial load operation dea grinding unit 7 and cooled via the compressed air connection 21 and the accumulation conveyor 22 in the coal dust line 15 and. conveyed and bunkered in the dust bin 6 · The conveying air is separated in the cyclone 16 and over the. Line 20 added to the combustion chamber «If the temperature of the sucked-up flue gases is too low to produce a bunker and ignitable dust, the auxiliary burner 4 can be put into operation«

The plant according to the invention has the advantage that it can now be approached from the cold state of the combustion chamber and the amount of pulverized fuel required for a startup process is so low that the dustbin volcanoes (- ^ 5 nr) which are permissible in the boiler house are largely protected.

is exceeded (approx. 1 m / 30 min start-up time) · The maximum bunkering temperature of 60 ⁰ G is adhered to and a coal dust is produced which is bunker-capable and ignitable and allows ignition, start-up and operation of the furnace. In addition, additional expenses such as separate heated transfer station with GIeisanschlußj tank farm with pump, day tank in the boiler house, piping with heat tracing and burner accounts. On the other hand, bunkering can take place without additional safety measures due to the cooled coal dust line 15. The simplified technology increases the functional safety and the occupational safety factor.

Claims (2)

Inducement 1 "ignition" and treatment plant for lignite-fired steam generators consisting of a grinder with classifier, a coal chute with a collector sucked back with sucked flue gases, a coal dust bunker, an ignition and one or more main burners, characterized in that the coal chute (3) by a in that the pulverized coal fired auxiliary burner (4) is heated so that the grinder (7) immediately supplies ignitable and combustible pulverized coal, and that the grinder (7), including the associated separator (8), is passed through a broth separator (8). 12) and a dust conveyor (22) with a cyclone (16) and thus the coal dust bunker (6) leading, cooled coal dust line (15) is connected » 2. Ignition and treatment plant according to item 1, characterized in that the pumped medium in the pulverized coal pipe (15) is cold conveying air * 3 · Ignition and treatment plant according to item 1, characterized in that the auxiliary burner (4) is arranged before the coal incidence in the flue gas return line (1) » 4 · Ignition and treatment plant according to items 1 to 3, characterized in that the ignition and support burner (14) from the dust conveyor (22) on the dust line (13) is fired ». , -. 5 »Ignition and treatment plant according to item 1 to 3, characterized in that the ignition and support burner (14) is fired with dust from bunker (6) * 6 · Ignition and treatment plant according to items 1 to 3, characterized in that in the bunker (6) Premdstaub is bunkered from another processing plant via coal dust line (19) · 7ο ignition and treatment plant according to items 1 to 3, characterized in that the dust is discharged to other Ver * consumers over the coal dust line (19). 8 «ignition and treatment plant according to point 1,2 and 5, characterized in that the ignition and support burner (14) is the main burner * 1 sheet of drawings -