WO1995024591A1

WO1995024591A1 - Process and device for operating a pressure-loaded, lignite-fed, circulating fluidised bed furnace for composite power stations

Info

Publication number: WO1995024591A1
Application number: PCT/EP1995/000395
Authority: WO
Inventors: Hartmut Höhne; Franz Bauer; Hans-Joachim Krautz; Kurt STRÖER; Dieter Koritz; Hans-Joachim Meier; Jens Biet; Krystian Lipa; Michael Warnatz; Detlef Lemke
Original assignee: Veag Vereinigte Energiewerke Ag
Priority date: 1994-03-09
Filing date: 1995-02-03
Publication date: 1995-09-14
Also published as: AU1664895A

Abstract

In a new mode of operation, crude lignite (33) is previously dried and burned in the fluidised bed furnace (1). The thus generated smoke gas (4) is partially desulfurised, the solids contained in the smoke gas are separated in a cyclone (5) and returned to the fluidised bed furnace, and the crude gas (6) from the cyclone is cleaned in a hot gas filter (7). According to the invention, a gaseous heat transfer medium and/or a humidity binding or evaporating solid is added to and mixed with the crude lignite during its transport and/or crushing, then introduced (34) into the fluidised bed furnace. In order to increase the temperature of the smoke gas, a lignite dust-combustion air mixture is further blown into the fluidised bed furnace and/or smoke gas path and the smoke gas is further desulfurised.

Description

The invention relates to a method and an arrangement for operating a pressure-charged circulating fluidized bed combustion operated with lignite for a combined cycle power plant.

5

For the pneumatic conveyance of raw lignite in a fluidized bed furnace, it is necessary to dry the raw lignite in separate drying plants to such an extent that a free-flowing material is produced.

10 Separate drying systems, however, represent a high material and energy expenditure and require their own process control.

For predrying broken raw lignite before it is introduced into the fluidized bed furnace, it is known to use a special drying regime with steam fluid bed dryers, tube dryers and the like. Ä. To provide (e.g. DE 38 32 579; DD 232 338).

20 Furthermore, it has been known for a long time to dry the brown coal by introducing it into the solid circulation line of the fluidized bed furnace (for example DE 31 07 355; DE 36 25 992). However, it was found that this drying process is not suitable for pre-evaporation of the

25 to reach the lignite's humidity, because the extraction path is too short. The arrangement of special mixing aids also showed no improvement.

Due to the difficult to control drying, the combustion of the brown coal only produces flue gases with a temperature level which cannot be used as hot gases for a gas turbine or a waste heat boiler without further heating stages. In addition, there is the problem of desulphurization and dedusting of these 35 flue gases, keeping the fine dust away from the gas turbine and recognizing the contents of these fine dust. The flue gas generated by burning lignite in the reactor of the fluidized bed furnace is partially desulfurized in the fluidized bed and in the free space by the absorbers supplied, the solids of large grain size are separated off in the cyclone and returned to the reactor, and the raw gas is cleaned after cyclone in a hot gas filter and as clean gas in a gas turbine and / or fed into a waste heat boiler. The clean gas must be partially desulfurized in order to comply with the permissible pollutant emission values. To reduce NO _x in the flue gas and to improve the combustion behavior of the fuel, it is known to introduce gaseous fuels and / or additional air in the free space of the reactor or in the flue gas duct before or after the separator (DE 39 33 286, 35 44 887, 36 13 300 ). Although this is associated with an increase in the temperature of the flue gas, the heat introduced is not a decisive factor for a substantial increase in the temperature of the flue gas for the purpose of use in a gas turbine or a waste heat boiler. In addition, an additional fuel supply for the fluidized bed combustion operated with lignite is required.

When generating hot gas in a fluidized bed furnace or in a fluidized bed gasification system, despite the cyclone separation and hot gas filter cleaning, the hot gas contains particles which, particularly on the blades of gas turbines, lead to buildup and corrosion damage, but above all to a reduction in efficiency and the service life of the Restrict the turbine.

There has been no shortage of attempts to avoid these disadvantages.

It is known to endure particles using precision filters or multiple filters (DE 30 31 923.35 06 102)

Additive addition precipitate (DE 42 30 482, 24 21 927) by

Separate agglomeration (DE 42 30 482, 36 40 743) by To separate the conditioning (DE 27 01 498, 36 16 805, DE 42 22 870), to remove it by forming a protective layer (DE 32 11 583, 39 26 479), to flush it away by cleaning technologies, to discharge it through outlets on the gas turbines (DE 20 33 353, 27 32 344, 30 36 525, 38 05 961) or by neutralizing the characteristic parameters (DE 22 12 255, 30 24 474).

The sealing of the filter candles in a receiving base are complex sealing constructions (DE 39 38 264, DE 37 19 944) or weight-loaded seals (DE 42 40 202, 32 34 321, 15 07 846).

In addition, monitoring arrangements (DD 201 855, DD 228 176) or shut-off arrangements for defective filter cartridges (DE 40 08 742) are required for monitoring, which require further expenditure. Despite these expenses, the tightness is not guaranteed, so that the resulting dust loads of the clean gas lead to malfunctions such. B. lead in the gas turbine.

However, these measures can only be carried out with considerable technical and technological expenditure and require considerable intervention in the system to be considered, with the desired advantages generally not being achievable.

The by burning brown coal z. B. generated in a pressure-charged circulating fluidized bed combustion hot gas for a gas turbine or a waste heat boiler (combined cycle power plant) is pre-cleaned in a cyclone and cleaned in a filter candle (e.g. VGB 1992 pp. 1 - 13, DE 31 44 675). The desulfurization of the Sθ3-containing hot gas takes place on the basis of the absorbers (lime) introduced in the fluidized bed (approx. 30%) and in the free space (approx. 50%) of the fluidized bed reactor. The clean gas present after the filter candle with a max. Dust content of 5 mg / m ^ N (permissible low clean gas dust content) still has an Sθ3 ~ content of approx. 20%. In order to comply with the Sθ3 emissions after the gas turbine or waste heat boiler, it is necessary to reduce the Sθ3 content considerably, so that considerable expenditures for absorbents, desulfurization plant technology and management are necessary. Another problem for the operation of the pressure-charged circulating fluidized bed combustion is the entry of raw lignite.

The supply of pre-crushed raw lignite to a circulating pressure-charged fluidized bed furnace is generally carried out by means of fuel feed and metering directly on the circumference into the fluidized bed (e.g. DE 36 19 141, DE 37 26 643, 40 07 635, 40 29 065, 41 05 227).

In order to achieve an even distribution in the fluidized bed, considerable technical and / or technological measures are necessary. The supply of the fuel via a swirl shaft also has advantages in terms of conveyor technology, but the operational management is extremely complex.

The invention is therefore based on the object of developing a method and an arrangement for a new mode of operation of a circulating pressure-charged fluidized-bed furnace operated with raw lignite.

This is achieved in that, according to the invention, a gaseous heat transfer medium and / or a moisture-binding or a moisture-evaporating solid is added to the raw lignite on the conveying path and / or in the comminution process, and mixed with this and introduced into the fluidized-bed furnace and that a lignite dust is used to increase the temperature of the flue gas Combustion air mixture additionally blown into the fluidized bed combustion and / or flue gas path and the flue gas is further desulfurized. To implement the method, metering devices for the gaseous heat transfer medium and for the moisture-binding solid are arranged on the raw lignite conveying path and / or on the comminution devices, and that the solid circulation line, the bedding material discharge line and the filter ash are jointly or optionally The delivery line and the raw lignite delivery line are integrated via closure devices in a pressure vessel provided with pressure medium lines and the pressure vessel is integrated into the fluidized bed furnace via the circulation line with closure device and that a lignite dust / combustion air mixture duct is connected to the air stages of the fluidized bed furnace and / or to the flue gas duct is involved.

The invention is explained in more detail using an exemplary embodiment. The accompanying drawing shows:

- Fig. 1: The principle of coaling and predrying the

Raw lignite for fluidised bed solids using gaseous heat transfer media and moisture

- Fig. 2: The principle of coaling and predrying the

Raw lignite for fluidized bed combustion using moisture-evaporating solids

- Fig. 3: The formation of the drying pressure vessel after

Fig. 2

- Fig. 4: The principle of the supply for the lignite dust-combustion air mixture

- Fig. 5: The basic structure of the ceramic filter candle arranged in the hot gas path - Fig. 6: The formation and arrangement of the ceramic

Candle filter

7: The formation of the sealing surfaces of the filter candle according to FIG. 6

- Fig. 8: The principle of feeding the raw lignite over the container arrangement

- Fig. 9: The arrangement principle of particle size reduction

- Fig. 10: The arrangement of sound generators on the

Channel section according to FIG. 9

- Fig. 11: The arrangement for coupling the excitation and

Detection arrangement for the determination of alkalis

The conveyor 1 is integrated into the intermediate bunker 3 via the crusher 2 (FIG. 1). The intermediate bunker 3 has the connections 4; 5; 6; 7 for flue gas 8; 9; 10; 11 on. The intermediate bunker 3 also has the connection 12, in which the line 14 and the metering and driving medium connection 15 are integrated and connected to the connection 7 via the line 18. The connections 4; 5; 6; 7 distributed over the height and circumference of the intermediate bunker 3. The intermediate bunker 3 has the vapor line 27. The intermediate bunker 3 is connected to the pressure-charged feed bunker 21 via the conveyor 19. The crusher 20 is optionally integrated into the conveyor 19. The feed hopper 21 is connected via the pneumatic conveyor 22 having the conveying air line 34 to the pressure-charged fluidized bed furnace 23, which has the primary air line 24, the inflow floor 32 and the flue gas duct 25. It is readily possible to additionally apply flue gas and quicklime in the crusher 2, conveyor 1, conveyor 19, crusher 20 and / or feed hopper 21.

The mode of action is as follows:

The mine-moist raw lignite with a moisture> 50% and a grain size> 60 mm reaches the crusher 2 via the conveyor 1 and is pre-crushed there, so that a grain size of ≤ 40 mm is achieved. The raw lignite 26 thus broken is conveyed into the intermediate bunker 3. Via the connections 4; 5; 6; 7 becomes flue gas 8; 9; 10; 11 introduced at the following temperatures:

Port 4 - flue gas 8: 70 ° C

Port 5 - flue gas 9: 150 ° C

Port 6 - flue gas 10: 180 ° C

Port 7 - flue gas 11: 230 ° C

The various temperature levels can also be reached by a staged supply of the flue gas flow. At the same time, the flue gas 16 reaches a temperature of 230 ° C. as a partial flow via line 18 to the metering and driving medium connection 15, at which the quicklime 17 is present via line 14. As a result, the flue gas (propellant) / quicklime mixture 13 reaches the intermediate bunker 3 via the connection 12, and the raw lignite stream achieves a substantially improved flow behavior at the bunker outlet.

With the flue gas 8; 9; 10; 11, the gradual drying of the raw lignite 26 takes place, the moisture (water) bound and free in the raw lignite 26 being removed via the vapor line 27 as vapors 29. The vapor 29 with a temperature of 90 ° C to 110 ° C is, for. B. conveyed into a combustion chamber or a vapor cleaning device. The through the smoke 8; 9; 10; 11 gradual thermal treatment of the raw lignite 26 leads to surface drying and to gradual chipping of the dried surface layers on the individual grain of the raw lignite 26. This process is repeated continuously over the height of the intermediate bunker 3. With the introduced propellant-quicklime mixture 13, the further thermal Treatment of the raw lignite 26 so that the wet surface exposed by the flaking off of the dried surface layer on the single grain is coated with the quicklime introduced. This in turn binds this surface moisture. The raw lignite 31 treated in this way arrives in the conveyor 19 and is mechanically comminuted step by step on the conveying path in that further surface layers on the individual grain flake off. The exposed wet surface is coated again with the quicklime and the surface moisture is thus bound again. If the raw brown coal 26; 31 should have a grain size <6 mm, the raw brown coal 31 is further crushed in the crusher 20. In particular, the dry surface layers on the individual grain are separated and the exposed wet surface is covered with quicklime again. The raw lignite 31 then passes into two mutually pressure-charged feed bunkers 21. The raw lignite 31 has a surface moisture <40% and a grain size <6 mm, so that a free-flowing raw lignite 26 is produced. The treated raw lignite 26 is conveyed by means of the driving medium 33 through the pneumatic conveyor 22 into the pressure-charged fluidized bed furnace 23. Flue gas, pressurized air or steam can be used as the driving medium 33, so that further drying takes place. The S0 _X released in the combustion process is bound by the raw lignite 26 coated with the quicklime, so that the desulfurization of the flue gases 28 takes place within the fluidized bed furnace 23. The following advantages are achieved by the invention:

1. Generation of a free-flowing raw brown coal suitable for pneumatic conveying.

2. Drying, crushing and binding of the surface moisture takes place in the existing conveying process.

3. The provision of the dry medium and quicklime does not require any special system technology or

Driving style.

4. Avoiding the formation of bridges in the intermediate bunker.

5. Simple technical and technological solution for binding the S0 _X released in the combustion process.

The reactor 1 of the fluidized bed furnace has the primary air supply 2, the bed ash discharge 3 and the flue gas duct 4 (FIG. 2).

The flue gas duct 4 is integrated in the cyclone 5. The cyclone 5 is connected via the raw gas channel 6 to the hot gas filter 7 with filter ash discharge 27. The hot gas filter 7 is integrated above the clean gas duct 8 and the gas turbine 9 into the waste heat boiler 10 with the exhaust duct 20. The compressor 11 is connected to the primary air supply 2 via the pressure line 12. The circulation line 13 of the cyclone 5 is integrated into the lower part of the pressure container 15 via the closure device 14. The brown coal feed 16 with the closure device 17 and the compressed air line 18 with the closure device 19 is integrated in the upper part of the pressure vessel 15. The compressed air line 18 is integrated in the pressure line 12. The line 21 branches off from the flue gas line 4 and is connected to the circulation line 13 via the closure device 22. The circulation line 28 with closure device 29 connects the pressure vessel 15 to the reactor 1. The circulation line 13 is optionally connected via line 23 to the bed ash discharge 3 and / or via line 24 to the filter ash discharge 25. The circulation line 13 can also be integrated into the pressure vessel 15 in such a way that it is connected to the distribution device 32 arranged in the pressure vessel 15 (FIG. 3). The distribution device 32 has openings for the discharge of solid and flue gas.

The mode of action is as follows:

The pressure container 15 is opened with the closure device 17 and the closure devices 14; 19; 22 filled with raw lignite 33 to about 70%. Then the closure device 17 is closed and the closure devices 14; 22 open. The cooled solids 27 to be returned from the cyclone 5 arrive together with the flue gas 26 in the pressure vessel 15, flow through the raw lignite, so that an effective heat exchange takes place. At the same time, the pressure vessel 15 is biased by the flue gas 26. Then the closure devices 14; 17; 22 closed and the closure device 19 opened. With the compressed air 35 from the compressor 11 from the pressure line 12, the pressure vessel 15 is tensioned via the pressure line 18. After a pressure of approximately 14 bar has been reached, the closure device 19 is closed and the closure device 29 is opened, so that the crude lignite-solid mixture 34 is conveyed from the pressure vessel 15 via the circulation line 28 into the reactor 1. The raw lignite is further pre-dried so that a combustion-active raw lignite is produced. Then the closure device 29 is closed and the closure device 17 is opened so that the cycle can be carried out again. The cycle - filling, tensioning, emptying - of the pressure container can of course also be carried out with several containers. The drying of the raw lignite 16 is also readily ensured with cooled bedding materials 30 to be returned from the reactor 1 and / or cooled filtering materials 31 to be returned from the hot gas filter 7. If the heat balance of the heat transfer medium is sufficient, a high drying effect of the brown coal is possible. If the heat balance of the heat transfer medium is not sufficient, it is possible to achieve a partial drying effect of the brown coal or to dry only a partial flow of the brown coal with a high drying effect and to combine the partial flows before fluidized bed combustion. The surface moisture of the moist lignite entered certainly prevents coking if the heat transfer medium has temperatures leading to coking. The vapors generated in the pressure vessel serve to further loosen the brown coal and are relieved of work in the gas turbine at the end of the process.

The reactor 1 has the primary air supply 2, the

Fuel feed 3, the solids return 4, the

Secondary air step 5, the tertiary air step 6 and the flue gas duct 7 (FIG. 4).

The flue gas duct 7 is integrated in the cyclone 8, which is connected to the solids return 4. The

Raw gas channel 9 of the cyclone 8 is integrated in the hot gas filter 10 with filter candle 11. The clean gas channel 12 of the hot gas filter 10 is connected to the gas turbine 13 and the waste heat boiler 14.

The compressor 15 is connected to the primary air supply 2 via the duct 16. In the secondary air step

5 (A) and / or the tertiary air level 6 (B) are the brown coal dust pipes 17; 18 involved, which are connected to the brown coal dust supply 19. The additional additional air step 20 (C) with brown coal dust line 21 is arranged above the tertiary air step 18.

It is easily possible to integrate the brown coal dust line 22 with additional air line 23 before (D) and / or the brown coal dust line 24 with additional air line 25 after (E) the cyclone 8 in the flue gas duct 7 and / or the raw gas duct 9.

The mode of action is as follows:

In the reactor 1, the brown coal 25, the combustion air 26, the recycled solids 27 from the cyclone and other absorbents to be fed are burned. The flue gases 28 produced in this way are partially desulfurized in the fluidized bed and in the free space of the reactor 1, so that the SO 3 content is reduced by approximately 80%. To increase the temperature of the partially desulfurized flue gases 29 in the secondary air step 5 and / or in the tertiary air step 6 and / or additional air step 20 via the brown coal dust lines 17; 18; 21 supplied brown coal dust 30 burned (A; B; C). To further increase the temperature, it is easily possible to use the brown coal dust lines 22; 24 lignite dust 30 and via the additional air lines 23; 25 Bring combustion air via burner devices (not shown) into the flue gas duct 7 and / or raw gas duct 9 and burn them. The raw gas freed from the solids of coarser grains in the cyclone 8 contains very fine particles of absorbents (e.g. lime), solids (ash from lignite and lignite dust) and gaseous SO3 (approx. 20%). In the hot gas filter 10, the raw gas 9 is cleaned and partially desulfurized, in that the filter cake of the filter candle 11, which is constantly formed from fine lime and fine pockets, absorbs the S03 components and CaS04 is formed. When the filter candle 11 is cleaned, the filter cake assembled in this way is withdrawn from the hot gas filter 10. In addition, the filter candle 11 and the solids and gaseous particles contained in the flue gas are bound to the filter cake. B. alumina, fail. That is, the very fine parts of the substances mentioned are also bound to the surface of the filter cake and fall out of the circuit when the filter candle 11 is cleaned. This largely avoids corrosion attacks on the blades of the gas turbine.

The following advantages are achieved by the invention:

1. A significant increase in the efficiency of the overall processes is achieved by increasing the temperature.

2. In spite of the brown coal dust being introduced, a favorable partial desulfurization occurs in the free space of the reactor and on the filter candle.

3. Despite the introduced brown coal dust and the combustion air, the system does not malfunction due to the changed quantity balance.

The pressure-charged circulating fluidized bed furnace has the reactor 1 with lignite feed 2, primary air step 3, secondary air step 4 and tertiary air step 5 (FIG. 5). The reactor is connected to the cyclone 7 via the hot gas channel 6. The cyclone 7 is connected to the brown coal supply 2 via the circulation line 8. The raw gas channel 9 of the cyclone 7 is integrated in the ceramic filter 10. The raw gas space 11 with ash removal 12 and the clean gas space 13 with cleaning device 14 is formed in the container 21 and the filter candle 15 is arranged. The clean gas duct 16 of the filter container 21 is connected to the waste heat boiler 18 via the gas turbine 17. The compressed air line 19 of the compressor 20 is with the air steps 3; 4; 5 connected.

The mode of action is as follows:

The hot gas is generated in the reactor by burning the supplied lignite, the combustion air and the absorbents in the form of lime and regenerated solids, the Sθ3 ~ content in the fluidized bed of the reactor 1 is reduced by about 30%. Around 50% of the SO3 content of the hot gas is reduced in the free space of the reactor. The hot gas, which has an Sθ3 content of approximately 20% and solids, enters the cyclone 7. The solid fraction of larger grain size in the form of lime and ash is separated off in the cyclone 7 and returned to the reactor 1. The raw gas pre-cleaned in this way passes from the cyclone 7 into the ceramic filter 10. The raw gas has the solid content of small particles in the form of fine lime and fine pockets as well as the SO3. This raw gas flows into the raw gas space 11 and to the filter candle 15. The filter cake 22, consisting of fine lime and fine pocket, is formed on the filter candle 15. The SO3 of the raw gas is bound to the surface of this filter cake 22 and CaS04 is formed. This binding of the SO3 to the surface of the filter cake 22 is possible as long as the surface of the filter cake 22 is newly formed by further fine lime and fine pocket in the raw gas. If the pressure loss through the filter candle 15 becomes too high due to the growth of the filter cake 22, the cleaning device 14 causes a blast of compressed air into the interior of the filter candle 15. As a result, the filter cake 22 is detached from the surface. The detached particles are removed from the filter container 21. The cleaned and partially desulfurized clean gas enters the gas turbine 17 and the waste heat boiler 18, the pollutant emissions (fine dust, SO3) being reduced to the permissible limit values. In addition, the solids and gaseous particles in the flue gas are bound to the filter cake 22 of the filter candle 15, which are released due to the combustion of the brown coal in the form of alkali metal compounds and the additives added to bind these compounds, e.g. B. alumina, fail. This means that the very fine parts of the substances mentioned are also bound to the surface of the filter cake and fall out of the circuit when the filter candle is cleaned. This largely avoids corrosion attacks on the blades of the turbine.

The boiler 1 with the fuel supply 2 of the air line 3, fan 4 and suction air line 5 has the flue gas duct 6 (FIG. 6). The flue gas duct 6 is connected to the ceramic candle filter 7. The clean gas line 8 leads to the gas turbine 9. The ceramic candle filter 7 consists of the filter space 10, the leakage gas space 11 and the clean gas space 12. The leakage gas space 11 is connected to the leakage gas line 13 having the controller 27, which in the gas heat exchanger 25, the suction air line 5, in the low-pressure region 14 or into the exhaust pipe 15 of the gas turbine 9. The ceramic candle filter 7 has the filter candle 16 with the sealing surfaces 17.1; 17.2 on (Fig. 7). The sealing surface 17.1 is arranged in the base 18 as a partition between the filter space 10 and the leak gas space 11. The sealing surface 17.2 is arranged in the base 19 provided between the leak gas space 11 and the clean gas space 12. The mode of action is as follows:

The flue gases 20 of the boiler 1 are introduced via the flue gas duct 6 into the filter space 10 of the ceramic candle filter 7, passed through the filter candles 16 and dedusted. The cleaned (dedusted) clean gas 21 is passed via the gas turbine 9 into the exhaust line 15. The exhaust gas 22 after the gas turbine 9 with a low pressure-temperature level is fed to the further process. If leaks occur on the sealing surfaces 17.1; 17.2, the dust-laden leakage gas quantities 23 and the clean gas leakage quantities 24 are passed from the leakage gas space 11 via the leakage gas line 13 as leakage gas 26 into the gas heat exchanger 25, into the suction air line 5 before the fan 4, into the vacuum region 14 or into the exhaust gas line 15 to the gas turbine 9. With the help of the controller 27, the pressure level in the leakage gas chamber 11 is set such that the pressure P2 of the leakage gas 26 is slightly below the pressure P3 of the clean gas 21 in the clean gas chamber 12, so that the leakage gas quantities 23; 24 be kept low. The pressure Pi of the flue gas is greater than the pressure P2; P3 of the leak gas 26 and the clean gas 21.

The following advantages are achieved by the invention:

- Simple construction of the sealing surfaces on the candle filter

- No additional space required in the filter room for sealing surface pressure systems

- Use of the amount of leakage gas in the heat release process

- Filter candle breaks have no effect on the clean gas quality The fluidized bed pressure vessel 1 with the fluidized bed combustion 2 has the air supply 3 with fan 4 (FIG. 8). The fluidized bed firing 2 has the nozzle base 5 with the air nozzles 6 and the fuel gas discharge line 7. The fuel tanks 8.1 ... 8.n are arranged above and / or to the side of the fluidized bed pressure tank 1. The fuel tanks 8 have the fuel supply 9 with lock 10 and the additive line 11. The primary crusher with screening plant 12 is arranged in the coal transport system 28. The fuel tank 8 has the nozzle base 13 and the air chamber 14 with the air line 15, in which the fan 16 is arranged. In the upper part 17 of the fuel tank 8 there is the air / dust line 18. The air / dust line 18 has the connection 19 as a primary, secondary or tertiary air line in the nozzle base 5 and / or the connection 20 with controller 21 as a combustion air line on. Immediately above the nozzle base 13, the fuel tube 22 with the regulator 23 and the dip tube 24 with the mouth 25 is arranged in the region of the fluidized bed 26.

The mode of action is as follows:

Fuel 27 is fed to the crusher 12 via the coal transport system 28 and comminuted accordingly. The crushed coal 29 passes through the lock 10 in the

Fuel tank 8. At the same time additive 30 over the

Additive line 11 fed. The so brought

Fuel-additive mixture is loosened by compressed air 31 above the nozzle base 13 and kept flowable.

The loosening air 32 reaches the fluidized bed 33 as

Combustion fluidized bed air 34 in the nozzle base 5 and / or via the integration 20 and the controller 21 as combustion air 35 in the fluidized bed combustion 2. The loosened, flowable fuel-additive mixture 36 in the fuel tank 8 reaches the fuel tube 22, from there via the controller

23 for fuel load control of fluidized bed combustion 2 in the dip tube 24. Via the mouth 25, the mixture 36 is fed directly into the fluidized bed 26. To maintain a continuous flow of fuel to the fluidized bed, the corresponding fuel tank 8.1; 8.2; 8.n loaded, tensioned and emptied. The pressure in the fuel tanks 8 is greater than the pressure in the fluidized bed pressure tank 1. The fuel tank 8.1 is loaded in the depressurized state. After the coal has been charged, the fuel and additive supply is shut off in a pressure-resistant manner and the fuel tank is charged with compressed air 31 and then emptied. The cycle loading, clamping, emptying is controlled accordingly.

The fluidized bed combustion or the fluidized bed gasification 1 has the primary air line 2, the fuel supply 3, the solids return 4 and the hot gas duct 5 (FIG. 9)

The hot gas duct 5 is integrated in the cyclone 6. The cyclone 6 is connected to the hot gas filter 8 via the raw gas channel 7. The clean gas duct 9 is integrated into the gas turbine 10, which is coupled to the compressor 11. The compressor 11 has the air inlet 12 and the exhaust air line 13, which is connected to the primary air line 2. The gas turbine 10 is connected to the waste heat boiler 15 via the exhaust gas duct 14. The clean gas duct 9 has the coupled sound generator 16 before entering the gas turbine 10. The clean gas duct 9 has the duct section 22 with the length L, on the wall of which the sound generator 16. 1; 16. 2; 16. 3 are coupled (Fig. 10).

The mode of action is as follows:

The hot gas 19 generated by combustion or gasification of lignite 17 in the fluidized bed combustion or fluidized bed gasification 1 has, due to the lignite 17, the recycled solids 18 and that with the lignite 17 introduced additives solids, which are contained in a wide range of grits with different compositions in the hot gas 19. In the cyclone 6 the solids are separated with a coarse grit belt and returned. The raw gas 20 is cleaned in the hot gas filter 8 in such a way that the solids are separated with a fine grain belt. In contrast, in the clean gas 21 there are still particles with a finest grain size band, which have a different mass spectrum, a different material composition and different binding forces. These properties depend on the fuels and additives used, as well as the combustion process and the cleaning quality of the hot gas filter. So that the particles in the blades of the gas turbine 11 do not lead to buildup, the clean gas 21 is subjected to the sound field of the sound generator 16. Using the sound field, 21 vibrations are generated in the particles in the clean gas, which lead to the destruction of the internal structure and thus to the disintegration of the particles if the binding energy is exceeded. The comminuted particles are passed through the blades of the gas turbine 10 with the stream of the treated clean gas 23, without these leading to substantial buildup on the blades. The sound generator 16 (FIG. 10) is coupled to the wall of the channel section 22 such that the sound generator 16. 1 in the conveying direction of the clean gas 21 with a low frequency fl, the sound generator 16. 2 with a medium frequency f2 and the sound generator 16. 3 is operated at a high frequency f3, the frequencies being set at fl <f2 <f3. The frequencies fl; f2; f3 are determined experimentally and depend on the properties mentioned. Particles of large grain size with very different material composition and small binding forces are crushed with the frequency fl. Particles of the smallest grain size with a uniform material composition and large binding forces are comminuted with the frequency f3, so that the treated clean gas 23 is present. The length L of the channel section 22 and / or the number of sound generators 16.1; 16.2; 16.3 ... 16.n is dependent on the conveying speed of the clean gas 21 and on the quality of the resonance behavior of the particles and must also be determined experimentally.

The following advantages are achieved by the invention:

1. Extend the life of the gas turbine

2. Extension of maintenance intervals

3. Despite the constant amount of dust, the tendency to build up is reduced due to the changed grain spectrum and the increase in the fine grain fraction.

In the hot gas duct 1 in front of the gas turbine, the high-frequency induction coil 2 is inserted as a thermal excitation section and connected to the controllable high-frequency generator 3 (FIG. 11). The quartz light guide 4 is arranged on the hot gas duct 1 via the quartz window 6 as an optical detection arrangement and is connected to the evaluation device 5. Arc electrodes can also be used as the thermal excitation path and can be connected to the controllable direct current generator 9.

It is also readily possible to use the thermal excitation section 2 together with the optical detection arrangement 4 as a component in the hot gas duct 1. The mode of action is as follows:

In the hot gas duct 1, the hot gas generated by the pressure-charged fluidized bed furnace is transported to the gas turbine as a hot gas stream 7 (FIG. 11).

Due to the combustion of brown coal, the hot gas contains u. a. following ingredients:

Na2SO4, - Na2 0; NaCl

K ₂ SO4; K ₂ 0; KC1

The high-frequency energy generated by the high-frequency generator 3 is coupled into the hot-gas stream 7 of the hot-gas duct 1 via the induction coil 2. The thermal energy generated by this splits the above. Alkali compounds so that the alkali atoms emit light with their specific wavelength. This light is detected by the optical detection arrangement 4 and given to the evaluation device 5 and the concentration of the above. Ingredients found.

The following advantages are achieved by the invention:

1. All ingredients contained in the hot gas flow, which lead to corrosion on the gas turbine blades, can be detected directly.

2. Due to the excellent controllability of the energy to be coupled in, there are different ones

Analysis tasks regarding the ingredients can be carried out. List of the reference numerals used for FIG. 1

1 conveyor 31 raw lignite

2 crusher 32 inflow floor 3 intermediate bunker 33 propellant

4 Connection 34 conveying air line

5 connection

6 connection

7 Connection 8 flue gas

9 flue gas

10 flue gas

11 flue gas

12 Connection 13 Flue gas / quicklime mixture

14 line

15 Dosing and drive media connection

16 flue gas

17 quicklime 18 pipe

19 sponsors

20 breakers

21 storage bunkers

22 Conveyors 23 Fluidized bed firing

24 primary air line

25 flue gas duct

26 raw lignite

27 vapor line 28 flue gas

29 brothers

30 raw lignite List of the reference numerals used FIGS. 2 and 3

1 reactor

2 Primary air supply 3 Bed ash discharge

4 flue gas duct

5 cyclone

6 raw gas duct

7 hot gas filter 8 clean gas channel

9 gas turbine

10 waste heat boilers

11 compressors

12 pressure line 13 circulation line

14 locking device

15 pressure vessels

16 lignite feed

17 Locking device 18 compressed air line

19 locking device

20 exhaust duct

21 line

22 closure device 23 line

24 line

25 filter ash discharge

26 flue gas

27 solids 28 circulation line

29 locking device

30 bedding

31 filter fabric

32 distribution device 33 raw lignite

34 Raw lignite-solid mixture

35 compressed air List of the reference numerals used for FIG. 4

1 reactor

2 Primary air supply 3 Fuel supply

4 Solids return

5 secondary air supply

6 tertiary air gradation

7 flue gas duct 8 cyclone

9 raw gas duct

10 hot gas filters

11 filter candle

12 clean gas duct 13 gas turbine

14 waste heat boiler

15 compressors

16 channel

17 Lignite dust pipe 18 Lignite dust pipe

19 Lignite dust feed

20 additional air gradation

21 Lignite dust pipe

22 Lignite dust pipe 23 Auxiliary air pipe

24 Lignite dust pipe

25 Auxiliary air line

26 Combustion air

27 solid 28 flue gas

29 flue gas

30 lignite dust List of the reference numerals used for FIG. 5

1 reactor

2 Lignite supply 3 primary air grading

4 secondary air gradation

5 tertiary air gradation

6 hot gas duct

7 cyclone 8 circulation line

9 raw gas duct

10 filters

11 Raw gas room

12 Ash removal 13 Clean gas room

14 cleaning device

15 filter candle

16 clean gas channel

17 gas turbine 18 waste heat boiler

19 compressed air line

20 compressors

21 filter container

22 filter cakes

List of the reference numerals used for FIGS. 6 and 7

1 kettle

2 Fuel supply 3 Air line

4 fans

5 suction air line

6 flue gas duct

7 ceramic candle filter 8 clean gas line

9 gas turbine

10 filter space

11 gas leakage

12 Clean gas room 13 Leak gas line

14 Low pressure area

15 exhaust pipe

16 filter candle 17.1 sealing surface 17.2 sealing surface

18 bottom

19 floor

20 flue gas

21 Clean gas 22 Exhaust gas

23 Leakage gas quantity

24 Clean gas leakage

25 gas heat exchangers

26 leak gas 27 regulator List of the reference numerals used for FIG. 8

1 fluidized bed pressure vessel 36 fuel-additive mixture

2 fluidized bed firing 3 air supply

4 fans

5 nozzle bases

6 air nozzle

7 Fuel gas discharge 8.1 ... 8.n fuel tank

9 Fuel supply

10 lock

11 Additive line

12 screening plant 13 nozzle floor

14 air chamber

15 air line

16 fans

17 Upper part 18 Air / dust line 19 Integration 20 Integration

21 controllers

22 Fuel tube 23 regulator

24 dip tube

25 confluence

26 fluidized bed

27 Fuel 28 Coal transportation system

29 coal

30 additive

31 compressed air

32 loosening air 33 fluid bed

34 Combustion fluidized bed air

35 combustion air List of the reference numerals used for FIGS. 9 and 10

1 fluidized bed firing

2 Primary air line 3 Fuel supply

4 Solids return

5 hot gas duct

6 cyclone

7 Raw gas duct 8 Hot gas filter

9 clean gas channel

10 gas turbine

11 compressors

12 Air inlet 13 Exhaust duct

14 exhaust duct

15 waste heat boilers

16 Ultrasonic generator 16.1 Ultrasonic generator fl 16.2 Ultrasonic generator f2 16.3 Ultrasonic generator f3

17 lignite

18 solid

19 hot gas 20 raw gas

21 clean gas

22 channel section

23 treated clean gas

24 air List of the reference numerals used for FIG. 11

1 hot gas duct

2 high-frequency induction coil 3 high-frequency generator

4 quartz light guides

5 evaluation device

6 quartz windows

7 hot gas flow

Claims

claims

1.Procedure for operating a pressure-charged circulating fluidized-bed combustion operated with lignite for a combined cycle power plant, in which raw lignite is pre-dried and burned in the fluidized-bed combustion and the flue gas generated is partially desulfurized, the solids of the flue gas are separated into a cyclone and returned to the fluidized-bed firing and the raw gas from the Cyclone is cleaned in a hot gas filter, characterized in that a gaseous heat transfer medium and / or a moisture-binding or a moisture-evaporating solid is added to the raw lignite on the conveying path and / or in the comminution process, and mixed with this and introduced into the fluidized bed furnace and in order to increase the temperature of the A lignite dust / combustion air mixture is additionally blown into the fluidized bed combustion and / or flue gas path and the flue gas is further desulfurized.

2. The method according to claim 1, wherein the raw lignite is mixed and predried with the solids and / or bedding materials to be removed and / or bedding materials and / or filtering materials to be removed and separated in a cyclone and returned to the fluidized bed, characterized in that optionally or together the solids, the bedding materials and the filter materials are cooled, entered into a pressure vessel filled with the raw lignite, raw lignite and input substances are mixed, the pressure vessel is tensioned and the mixture is entered into the fluidized bed furnace in a controlled manner.

3. The method according to claim 2, characterized in that the pressure vessel is biased with flue gas and tensioned with compressor air.

4. The method according to claim 2 and 3, characterized in that the flue gas or exhaust gas is drawn off before and / or after the cyclone and / or hot gas filter.

5. The method of claim 1, wherein the pre-dried lignite is burned in the fluidized bed and the flue gas is partially desulfurized, the solids of the flue gas are separated in a cyclone and the raw gas from the cyclone is cleaned in a hot gas filter and as a clean gas of a gas turbine and / or is supplied to a waste heat boiler, characterized in that the brown coal dust / combustion air mixture with the secondary air step and / or tertiary air step is additionally blown in to increase the temperature of the flue gas.

6. The method according to claim 5, characterized in that the lignite dust-combustion air mixture is blown into the free space of the reactor and / or before and / or after the cyclone.

7. The method according to claim 1, wherein the raw lignite is pre-dried, characterized in that the raw lignite is added in the comminution process and / or on the conveying path of the gaseous heat transfer medium and quicklime, the raw lignite is gradually predried, gradually thermally and mechanically comminuted and gradually with the Quicklime is coated.

8. The method according to claim 7, characterized in that the gaseous heat transfer medium and quicklime is placed in a crusher and / or in the crusher discharge and / or in a closed conveyor and / or in the discharge chute and / or in a bunker.

9. The method according to claim 7, characterized in that the raw lignite is conveyed into an intermediate bunker of the coaling plant, the gaseous heat transfer medium is gradually fed to the raw lignite coal stream with increasing temperatures in the conveying direction and the quicklime with a gaseous heat transfer medium in the area of the bunker outlet into the raw lignite coal stream is dosed.

10. The method according to claim 7 to 9, characterized in that the quicklime is added in such a ratio that the quicklime is simultaneously used as an additive for the binding of S0 _X in the combustion of the raw lignite.

11. The method according to claim 1, wherein the pre-broken raw lignite is introduced into the circulating pressure-charged fluidized bed via a metering device, characterized in that the broken raw lignite is introduced as a quasi-thick material flow by means of gravity conveyance and is guided on a conveying path into the region of the fluidized bed.

12. The method according to claim 11, characterized in that the raw lignite is loosened, loaded, tensioned and conveyed through air in an allotment container arrangement.

13. The method according to claim 11 and 12, characterized in that the air introduced into the distribution container arrangement is introduced as primary, secondary and tertiary air into the fluidized bed furnace.

14. The method according to claim 11 to 13, characterized in that a dust-air mixture formed in the distribution container arrangement is introduced under, in and / or over the fluidized bed.

15. The method according to claim 11, characterized in that an additive is introduced into the distribution container arrangement with the coal.

16. The method according to claim 1 and 5, wherein the solids are separated from the flue gas in a cyclone and the raw gas is cleaned in a ceramic filter, characterized in that the filter candle of the ceramic filter is used for desulfurization of the raw gas, the Sθ2 ~ containing raw gas on the surface of the filter cake formed from fine lime and fine bag of the filter candle desulfurized to form CaSO 4 and the filter cake is cleaned in a manner known per se.

17. The method according to claim 16 for operating the candle filter, wherein the flue gas is introduced into a filter space, cleaned via the filter candles and discharged as clean gas from a clean gas space, characterized in that a leak gas is formed between the filter space and the clean gas space and passed into a negative pressure area of the flue gas generation system is, the pressure of the leakage gas is set lower than that of the clean gas.

18. The method according to claim 1 and 5, wherein the clean gas to avoid sticking to a part of the system acted upon by the clean gas, in particular on the blades of a gas turbine, characterized in that the clean gas with an electrical, piezoelectric, magnetic, sound, ultrasound , Shock wave, laser or microwave field is applied and the particles are crushed by the forces acting on the particles and exerted by the field.

19. The method according to claim 18, characterized in that the clean gas is supplied with the field of a frequency corresponding to the natural frequency of the particles.

20. The method according to claim 18 and 19, characterized in that the clean gas fl in the flow direction starting at low to higher frequencies fl; f2; f3 ... fn is applied, the frequencies fl <f2 <f3 ... <fn being set.

21. Arrangement for operating a pressure-charged circulating fluidized bed combustion operated with lignite for a combined cycle power plant, predrying being provided before fluidized bed firing and the flue gas duct being integrated into a hot gas filter via a cyclone and the cyclone separator being connected to the fluidized bed firing via a solids return, characterized in that on the raw lignite Conveyor path and / or metering devices for the gaseous heat transfer medium and for the moisture-binding solid are arranged and that together or optionally the solid circulation line, the bedding material discharge line and the filter ash delivery line as well as the raw lignite delivery line are integrated via closure devices in a pressure vessel provided with pressure medium lines and the pressure vessel via the circulation line with closure device into the US is integrated and that a lignite dust-combustion air mixture channel is integrated in the air stages of the fluidized bed combustion and / or in the flue gas duct.

22. The arrangement according to claim 21, characterized in that an intermediate bunker with connections for the gaseous heat transfer medium and with a propellant medium connection for quicklime is integrated in the conveying path.

23. The arrangement according to claim 21, characterized in that a multiple pressure vessel arrangement is provided.

24. The arrangement according to claim 21 for supplying raw lignite to the fluidized bed furnace, a coal conveying line being integrated into the fluidized bed furnace via a distributor device, characterized in that the coal conveying line is integrated into the fluidized bed furnace from above and with one up to the region of Fluidized bed guided conveyor and dip tube is connected.

25. Arrangement according to claim 24, characterized in that the coal conveying line is integrated in an allotment container arrangement, the containers of which are provided with a fluidized bed having an air line and the allotment container arrangement is connected to the fluidized bed furnace via an exhaust air line and as primary air, Secondary air, tertiary air and / or burnout air line is integrated.

26. The arrangement according to claim 21, characterized in that the lignite dust-combustion air mixture channel in the secondary and / or tertiary air lines and / or in the free space of the fluidized bed combustion and / or in the flue gas channel is integrated before and / or after the cyclone.

27. The arrangement according to claim 21 and 26, wherein the raw gas channel after cyclone in a filter space of a ceramic filter and a clean gas channel is integrated in the clean gas space, characterized in that the filter candle of the ceramic filter has a filter cake formed from fine lime and fine pocket.

28. The arrangement according to claim 27, characterized in that a leakage gas space is arranged between the filter space and the flue gas space, the filter candles are arranged via leakage gas sealing surfaces in the base plates of the filter and clean gas space and in the leakage gas space one with a negative pressure area of the flue gas generation system connected leakage gas line is integrated.

29. Arrangement according to claim 21 and 28 to avoid the adherence of particles carried in a clean gas line to a part of the system acted upon by the clean gas, in particular to the blades of a gas turbine, characterized in that a field generator, for. B. an electrical discharge device, a traveling field generator, an alternating field generator, a piezoelectric device, a shock wave generator, a microwave generator, an ultrasonic generator or a laser generator with different adjustable frequencies is coupled to a defined exposure path.

30. Arrangement according to claim 21 and 27 to 29 for the determination of alkalis in a hot gas flow at temperatures above 1000 ° C, wherein a thermal excitation section is used for the purpose of emission of the alkalis, characterized in that a high-frequency induction coil or as the thermal excitation section an arc electrode section is inserted directly into the hot gas duct and an optical detection arrangement known per se, which couples out the emitted light radiation, is arranged.

With this 10 sheets of drawings