AU651870B2

AU651870B2 - Dressing brown coal by carbonisation to coke prior to combustion

Info

Publication number: AU651870B2
Application number: AU12336/92A
Authority: AU
Inventors: Bernd Krodel; Reinhard Schneider
Original assignee: VEAG Vereinigte Energiewerke AG
Current assignee: VEAG Vereinigte Energiewerke AG
Priority date: 1991-02-15
Filing date: 1992-02-13
Publication date: 1994-08-04
Anticipated expiration: 2012-02-13
Also published as: DE59206243D1; DE4105127A1; EP0571445B1; AU1233692A; JPH06504568A; EP0571445A1; WO1992014803A1

Description

OPI DATE 15/n9/92 AOJP DATE 29/10/92

IN'

IN'I l,*t APPLN. ID 1236 92 PCT NUMBER PCT/DEq2/n0103OBER

DIE

ENS (PCT) (51) Internationale Patentklassifikation 5 Internationale Veriffentlichungsnummer: WO 92/14803 5/06, F01K 23/06 Al (43) Internationales Veroffentlichungsdatum: 3. September 1992 (03.09.92) (21) Internationales Aktenzeichen: PCT/DE92/00103 (81) Bestimmungsstaaten: AT (europiisches Patent), AU, BE (europaisches Patent), BG, CA, CH (europiisches Pa- (22) Internationales Anmeldedatum: 13. Februar 1992 (13.02.92) tent), DE (europiisches Patent), DK (europfisches Patent), ES (europaisches Patent), FR (europtiisches Patent), GB (europiisches Patent), GR (europlisches Pa- Priorittitsdaten: tent), HU, IT (europaisches Patent), JP, LU (europlii- P41 05 127.0 15. Februar 1991 (15.02.91) DE sches Patent), MC (europaisches Patent), NL (europiisches Patent), RO, RU, SE (europaisches Patent).

(71) Anmelder: VEAG VEREINIGTE ENERGIEWERKE AK- TIENGESELLSCHAFT [DE/DE]; Allee der Kosmo- Veriffentlicht nauten 29, D-1140 Berlin Mit internationalem Recherchenbericht.

(72) Erfinder: KRODEL, Bernd B.-Brecht-Str. 16, D-7544 Vetschau SCHNEIDER, Reinhard Neue Siedlung 4, D-7501 Kunersdorf (DE).

(74)Anwalt: VEAG VEREINIGTE ENERGIEWERKE AK- TIENGESELLSCHAFT; Referat Patent- und Lizenzwesen, Allee der Kosmonauten 29, D- 140 Berlin (DE).

651870 (54)Title: PROCESS FOR DRESSING BROWN COAL FOR COMBINED GAS AND STEAM PROCESSES (54) Bezeichnung: VERFAHREN ZUR BRAUNKOHLENAUFBEREITUNG FOR GAS-DAMPF-KOMBIPROZESSE (57) Abstract The invention concerns a process for dressing brown coal for combined gas and steam processes in heat-generating installations. The aim of the invention is to achieve substantial reduction of the CO 2 emission per useful effect unit by reduced use of fossil energy carriers; the devices for drying raw brown coal are to be connected to the heat-generating installation in such a manner that the energy of the exhaust vapours is fully utilized. To this end, raw brown coal is dried and dried brown coal is pyrolysed in two separate filled shaft reactors, but in direct succession; the drying reactor is heated indirectly with saturated steam and the pyrolysis reactor is heated indirectly with live steam 130 bar, 500 from a steam boiler with a pressurized-fluidized bed combustor; the coke is conveyed from the pyrolysis reactor into the same steam boiler and the pyrolysis gas, from which the dust is removed in the reactor, is conveyed from the same steam boiler into an additional burner which raises the temperature of the fluidized bed exha"st gases.

(57) Zusammenfassung Die Erfindung betrifft emn Verfahren zur Braunkohlenaufbereitung Rir Gas-Dampf-Koinbiprozesse in WMrmeerzeugungsanlagen. Der Erfindung liegt die Aufgabe zugrunde, elne deutliche Reduzierung der C0 2 -Emission je Nutzleistungseinheit durch verringerten Einsatz fossiler Energietrfiger zu erreichen, wobei die Trocknungseinrichtungen f'Or Rohbraunkohle so mit der Wfirmeerzeugu ngsani age verbunden werden, daRt elne volistandige energetische Verwertung des Biidens realisiert wird. Dies wird erf'indungsgemHU dadurch erreicht, d6~ die Trocknung von Rohbraunkohle und eine Pyrolyse von Trockenbraunkohle in zwei voneinander getrennten Schiittungsschacht-Reaktoren, jedoch in unmittelbarer Abfolge durchgeftlhrt werden, wobei der Trocknungsreaktor mnit Sattdampf und der Pyrolyse-Reaktor mit Frischdampf 130 bar, 500 IC) aus einem Dampfkessel mit einer Druck-Wirbelschicht-Feuerung indirekt beheizt werden, der Koks aus demn Pyrolyse-Reaktor in denselben Dampfkessel und das reaktorintern entstaubte Pyrolysegas in einen Zusatzbrenner zur Temperaturerhi6hung der Wirbel- .'chicht-Abgase aus gleichem Dampfkessel geleitet werden.

LEDIGLUCH ZUR INFORMATION Code, die zur Identifizicrung von PCT-Veriragsstaatcn auf den KoplFb~gen der Schriften, die 1 ntternationale Anmeldu ngen gemnfss demn PCI' verd1ffentlichen.

Austfuiiun Barbaidub IBulgarieu Ziiitrul Arr Lkji1j3J.11t RepuhlL C6ilt dvirL, Dhoemurk Fruiikru.ich Gjhiuia~ i Uingarn RepubIlL Korca i .hiuiiIn Sri Lak iLuxembhurg Mulluba Mungulul Mailawi Niu.JerlanJL! Runlliflun Russin1hu NHdrutinn Sudn Sdiwedern Vcrulidic Stuaten von AmriLu -1- PROCESS FOR DRESSING BROWN COAL FOR COMBINED GAS-STEAM PROCESSES The invention concerns a process for dressing brown coal for combined gas-steam processes in heat or power generating plants.

Known is a plant arrangement for drying raw coal prior to its use in the generation of electricity in condensation power plants. The known arrangement enables to fully utilise the condensation heat of the exhaust vapours but neither an exhaust vapour reverse compression nor a separate electric exhaust vapour dedusting are carried out. The drying is carried out in a filled shaft reactor provided with diaphragm tube walls which act as heating surfaces. Bleed steam from the main turbine of 15 the power plant is used as heating steam and supplied to the filled shaft reactor. The exhaust vapour obtained therefrom is de:usted at the exit into the exhaust vapour channel, i.e. when leaving the dryer, by means of a filter wall which can be steam cleaned (DD-PS 281 137) According to DD-PS 281 237, the energy of the exhaust vapour is fully utilised as secondary energy only in that it is divided into several and qualitatively different applications; this division requires an expensive integration of different appliances into the overall conception of the plant. In addition, this plant arrangement is intended exclusively for power plants in which the generation of electricity is effected in "pure" condensation operation only.

Further, it is also known to operate a combined gas and steam process in a power plant according to DE-OS 39 07 217. The process divides itself into two separate technological concepts or stages, of which the concept shown in Fig. 1 includes the operation of the pre-stage gas turbine with natural gas. This solution is a trivial one and has been employed commercially for a number of S:17950H/12.4.94 -2years. The second concept, shown in Fig. 2, includes a pressurised fluidised bed coal gasification of a partial coal flow. Since an additional fluidised bed drying of the steam is performed prior to the partial coal gasification, and the drying process is not energetically interconnected with the combined unit, the drying process has to be performed with reverse compression of the exhaust vapour and external vapour dedusting, both of which require a considerable amount of electric power.

As a result, the combined unit has a low overall degree of efficiency of 42-44%. The technical complexity of equipment required by this type of combined unit is substantial since it requires, in addition to the usual equipment of a typical combined unit, a gas turbine, an intermediate air cooling unit, connecting pipelines and channels, a pressurised fluidised bed gasification reactor with associated hot gas deduster and a drying *'.".equipment which is not energetically integrated into the 20 combined unit and therefore requires an extra power 20 supply.

does# It would be beneficial if the present invention could achieve in a power or heat generating plant a considerable reduction of CO 2 emissions per effective power output unit by using smaller amounts of fossil S: 25 energy carriers. Heretofore, it would be advantageous to integrate the drying devices for the raw brown coal into the heat generating plant in such a manner as to fully use the energy of the exhaust vapours.

Accordingly, the present invention provides according to one aspect thereof a process for dressing brown coal for combined gas-steam processes, wherein damp raw brown coal is conveyed through a pre-heater into a filled shaft dryer with indirect heating and internal exhaust vapour dedusting, and the obtained exhaust vapour is conveyed through an exhaust vapour condensating saturated steam generator into an air-heated intermediate S:179505/12.4.94 3 steam superheater, characterised in that the drying of the raw brown coal and a pyrolysis of the dried brown coal are carried out in two separate filled shaft reactors, yet in direct succession, in that the drying reactor and the pyrolysis reactor are indirectly heated with saturated steam and with live steam 130 bar, 500°C), respectively, from a steam boiler having a pressurised fluidised bed combustor, in that the coke is conveyed from the pyrolysis reactor into the steam boiler, and in that the pyrolysis gas, which is dedusted within the reactor, is conveyed into a supplementary burner to increase the temperature of the fluidised bed waste gases from the steam boiler.

The present invention will be more fully understood from the following description of an embodiment thereof drawings, in which: Fig. 1 shows part of a combined gas-steam heating plant having a filled shaft dryer and pyrolysis reactor.

20 As can be seen from Fig. 1, raw brown coal reaches a 0 0 pre-heater 2 of a combined gas-steam heating pla.nt (power plant) through an impact pulveriser chamber 1; the brown .coal is then conveyed into a filled shaft dryer 3. After drying of the coal has been effected, it is then conveyed 25 into a sluice container 4 located below the filled shaft dryer 3. A pyrolysis reactor 5 is situated below the sluice container 4 and is in connection therewith via a pressure-resistant cellular wheel sluice. Exhaust vapours formed in the pre-heater 2 and in the filled shaft dryer 3 are conveyed through a vapour channel 21 into a saturated steam generator 6 in which the exhaust vapour is condensed. Heating surfaces for heating steam 7 and for cooled live steam 8 are provided in the filled shaft dryer 3 and the pyrolysis reactor 5, respectively.

The combined unit includes an air compressor 9 which is S:17950H/12.4.94 -4 connected to an air-heated intermediate steam superheater The intermediate steam superheater 10 is also connected to a steam boiler 11 having a pressurised fluidised bed combustor, which draws a dry coal/coke/pyrolysis gas mixture through pressure pipeline 17 from the pyrolysis reactor 5. A supplementary burner 12 for pyrolysis gas conveyed through line 16 from the head region of the pyrolysis reactor 5 is connected with the steam boiler 11. The supplementary burner 12 produces hot gas which is supplied to a waste gas turbine 13 which is connected to a lost heat plant 14. A saturated steam generator 6 is connected to the cold line 18 of the intermediate steam superheater 10 via a saturated steam supply line 15. exhaust vapour filter 19 is arranged in the top region of the filled shaft dryer 3. A pyrolysis gas filter 20 is arranged in the top region of the pyrolysis reactor 5. The exhaust **vapour originating in the pre-heater 2 and in the Ssaturated steam generator 6 are respectively discharged through a common exhaust vapour condensate discharge line 22.

One advantage of the prfc4snt invention is that the combined gas-steam process to generate heat or electric power can be continuously operated with a degree of 25 efficiency of at least 50% and, inter alia, under a "06 partial load by dressing the raw brown coal in that it is dried, the energy of the exhaust vapour is utilised, the volatile components are expelled and coke is prepared.

Particular technical advantages are given in the thermal compression of the exhaust vapour and the pyrolysis gas, by which the operational gas volumes are considerably reduced, which in turn enables dedusting of the exhaust vapour and pyrolysis gas inside the reactors and to design and operate the gas-steam combined plant without an additional fuel gas compressor device.

S:1795OH/12.4.94 5 Dedusting of the pyrolysis gas is carried out using cleanable ceramic filter elements without prior temperature reduction of the gas and in a temperature range between 450 0 C and 500 0 C. The volatile components of the dry coal are expelled by indirect heating by means of live steam, enabling a separation of the energy flow supplied with the dry coal into a coke gas flow and into a pyrolysis gas flow. Thus, an optimum use of the fuel is assured during operation of the combined gas-steam plant.

o .000 9* S *0 *6 S:17950H/1.4.94 *5o2• e •S:7 5H/ 2 4 9

Claims

1. Process for dressing brown coal for combined gas- steam processes, wherein damp raw brown coal is conveyed through a pre-heater into a filled shaft dryer with indirect heating and internal exhaust vapour dedusting, and the obtained exhaust vapour is conveyed through an exhaust vapour condensating saturated steam generator into an air-heated intermediate steam superheater, characterised in that the drying of the raw brown coal and a pyrolysis of the dried brown coal are carried out in two separate filled shaft reactors, yet in direct succession, in that the drying reactor and the pyrolysis reactor are indirectly heated with saturated steam and with live steam 130 bar, 500°C), respectively, from 15 a steam boiler having a pressurised fluidised bed combustor, in that the coke is conveyed from the pyrolysis reactor into the steam boiler, and in that the pyrolysis gas, which is dedusted within the reactor, is conveyed into a supplementary burner to increase the temperature of the fluidised bed waste gases from the steam boiler.

2. Processes according to claim 1, characterised in that the live steam cooled off in the pyrolysis reactor is returned to the steam boiler with pressurised 25 fluidised bed combustor, reheated therein and subsequently conveyed to a steam turbine.

3. Process according to claim 1, characterised in that the dry coal is supplied from the drying reactor to the pyrolysis reactor through a sluice container havi.ig pressure-resistant cellular wheel sluices.

4. Processes according to claim 1, characterised in that deducting of the pyrolysis gas is carried out in the Ah top part of the pyrolysis reactor and the pyrolysis gas, S:17950H/12.4.94 -7 due to thermal compression, is delivered to the supplementary burner under pressure and dust-free. A process according to claim I as herein described with reference to Fig. 1. DATED this3 12th day of April 1994 VEAG VEREINIGTE ENERGIEWERKE By their Patent Attorneys GRIFFITH HACK CO *00 S :17950H/12 .4.94 4 t Abstract The invention concerns a treatment of brown coal for combined gas and steam processes in heat generating plants. The aim of the invention is to achieve considerable reduction of the CO2 emission per actual output unit by reduccd use of fossil energy carriers; the devices for drying brown coal are to be connected to the heat generating plant in such a manner that a complete energy utilisation of the exhaust vapour is realised. To this end raw brown coal is dried and dried brown coal is pyrolysed in two shaft reactors which are separate from each other, yet in direct succession; the drying reactor is heated indirectly with saturated steam and the pyrolysis reactor is heated indirectly with live steam 130 bar, 500*C) from a steam boiler with a pressurised fluidised bed firing equipment- the coke is conveyed from the pyrolysis reactor into the same boiler and the pyrolysis gas, from which the dust is removed in the reactor, is conveyed from the same steam boiler into a supplementary burner which raises the temperature of the fluidised bed exhaust gases.