DE19931346C1 - Drying method for brown coal supplied to steam turbine power plant uses turbulence layer drier heated via vapor compressed via compressor driven by steam turbine coupled to steam turbine power plant - Google Patents

Abstract

The drying method uses indirect drying of the brown coal via a turbulence layer drier (3), with part of the vapor extracted from the latter compressed and used for heating the turbulence layer drier, the remainder used as the turbulence layer. The compressor (6) is driven by a steam turbine (7) supplied with steam from the steam turbine power plant (1).

Description

The invention relates to a method for drying in one Steam turbine power plant raw lignite to be burned, in which Raw lignite from indirect drying in a fluidized bed dryer undergoes and a subset of that from the fluidized bed dryer withdrawn vapors compressed in a compressor and for heating the Fluid bed dryer is used and a different subset in the Fluid bed dryer is introduced as a fluidizing medium.

In this as a so-called WTA drying process and from the DE 195 18 644 A1 known method, the compressor for compression of the vapors powered by an electric drive. Because of the big one The vapor compressor has a very high capacity in large systems Power requirement that already makes great demands on the vehicle during the start-up process electrical network. In addition, in the steam turbine power plant Main turbine and the generator assigned to it correspondingly larger to interpret.

It is the object of the present invention, a method of Specify generic type in which these problems are avoided and the high power requirements of the compressor are easily met becomes.

This task is solved in that the compressor of one Drive steam turbine is driven, at least with steam from the Water-steam cycle of the steam turbine power plant is fed.  

This procedure does not impose any requirements on the network posed. The drive must be used when designing the main turbine and generator of the vapor compressor are no longer taken into account.

The drive steam turbine is preferably heated with steam from the hot Reheat fed. The drive steam turbine can also with Tapping steam fed from the main turbine or from the high pressure part become.

Advantageously, the drive steam turbine for the Vapor compressor steam for additional indirect heating of the Fluid bed dryer can be removed.

This additional steam becomes like the fed vapors in the Fluidized bed dryer condensed. In the so-called DWT process for Drying raw lignite using the fluidized bed dryer withdrawn vapors are condensed is the indirect heating of the Fluid bed dryer with steam known per se. Furthermore, it is from DE 196 12 186 A1 known, in addition to the indirect heating of the Fluid bed dryer tapping steam from the steam turbine power plant for the use indirect heating of the fluidized bed drying. This is about however, it is bleed steam from the main turbine of the Steam turbine power plant.

When using steam from the compressor drive turbine, it can make sense to drive the drive turbine completely in the counter pressure and the to supply the entire exhaust steam from the drive turbine to the fluidized bed dryer and condense there.

Finally, it is also possible that a partial flow of the uncompressed Vapor is passed over a heat exchanger in which from the water Steam circuit of the steam turbine power plant introduced feed water evaporates and the generated steam is fed to the compressor drive turbine becomes.

The invention will now be explained in more detail with the aid of the attached figures. It shows:  

Fig. 1 is a block diagram of a first embodiment in which the drive steam turbine is fed with steam from the hot reheat a lignite drying with a downstream steam turbine power plant,

Fig. 2 is a partial view corresponding to Fig. 1, wherein bleeder steam from the compressor drive turbine of the fluidized bed dryer can be supplied,

Fig. 3 is a view comparable to Fig. 2, wherein the compressor drive turbine having no own capacitor, and

Fig. 4 is a partial representation comparable to Fig. 1, in which a partial flow of non-compressed vapors is used to generate steam for the vapor compressor drive turbine.

Referring to FIG. 1 a steam turbine power plant 1 is a drying installation 2 of the upstream for drying raw lignite to be combusted RBK. The raw lignite RBK to be dried is fed to a fluidized bed dryer 3 . The vapors formed during drying are passed through a vapor filter 4 . A partial flow 5 a of the dedusted vapors is compressed in a vapor compressor 6 , which is driven by a vapor compressor drive turbine 7 , and fed to the heating surface 8 of the fluidized bed dryer 3 in order to heat it indirectly.

A partial stream 5 b of the dedusted vapors is fed to the fluidized bed dryer 3 as a fluidizing medium via a vapor circulation blower 8 , which is driven by an electric motor 9 .

The steam power plant 1 is shown schematically in FIG. 1 by a steam generator 10 , to which the dried lignite is fed via line 11 for combustion. A steam turbine brewing group 12 with an HP main turbine 13 and an MD / LP main turbine is assigned to the steam generator. A condenser 15 is connected downstream of the MD / LP turbine 14 and the condensate is fed again to the steam generator via line 15 '. The turbines drive a generator 16 . A hot ZÜ line 17 is provided between the steam generator 10 and the MD / LP main turbine 14 in a conventional manner. This representation of the steam power plant 1 is schematic. Further details of the water-steam cycle are not shown for the sake of simplicity.

Steam is withdrawn from the hot ZÜ 17 via a line 18 and fed to the vapor compressor drive turbine 7 . The vapor from the vapor compressor drive turbine is condensed into a condenser 19 .

In the embodiment according to FIG. 2, an additional heating surface 20 is provided in the fluidized bed dryer 3 , which is supplied with steam removed from the drive turbine 7 via a line 21 .

In the embodiment according to FIG. 3, the additional heating surface 20 in the fluidized bed dryer 3 is acted upon via line 21 'with the vapor of the vapor compressor drive turbine 7 , which is driven completely in counter pressure. A separate condenser for the drive turbine can then be omitted because all of the exhaust steam supplied via line 21 'to the heating surface 20 is condensed in the fluidized bed dryer.

In the embodiment according to FIG. 4, part of the steam required for driving the vapor compressor drive turbine is generated by passing a partial stream 5 c of the vapors over a heat exchanger 22 , in which the water-steam circuit of the steam power plant is removed via line 23 Water evaporates and the steam is fed via line 24 to the vapor compressor drive turbine 7 .

Combinations of the procedures are conceivable.

Claims (5)

1.Procedure for drying raw lignite to be burned in a steam turbine power plant, in which raw lignite is subjected to indirect drying in a fluidized bed dryer and a portion of the vapors drawn off from the fluidized bed dryer are compressed in a compressor and used for heating the fluidized bed dryer and another portion in the fluidized bed dryer is introduced as a fluidizing medium, characterized in that the compressor ( 6 ) is driven by a drive steam turbine ( 7 ) which is fed at least with steam from the water-steam circuit ( 17 ) of the steam turbine power plant ( 1 ). 2. The method according to claim 1, characterized in that the drive steam turbine ( 7 ) with steam from the hot reheat of the steam turbine power plant ( 1 ) is fed. 3. The method according to claim 1 or 2, characterized in that from the drive steam turbine ( 7 ) steam ( 21 ) for an additional indirect treatment ( 20 ) of the fluidized bed dryer ( 3 ) is removed. 4. The method according to any one of claims 1 to 3, characterized in that during operation of the drive steam turbine ( 7 ) completely in the counter pressure, the entire exhaust steam ( 21 ) of the drive turbine ( 7 ) is fed to the fluidized bed dryer ( 3 ) and condensed there. 5. The method according to any one of claims 1 to 4, characterized in that a partial stream ( 5 c) of the uncompressed vapors is passed into a heat exchanger ( 22 ) in which feed water is fed from the water-steam circuit of the steam turbine power plant ( 1 ) ( 23 ) evaporates and the generated steam ( 24 ) is fed to the compressor drive turbine ( 7 ).