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WO1997045675A1 - Procede pour recycler les cendres generees par les chaudieres a production de vapeur - Google Patents

Procede pour recycler les cendres generees par les chaudieres a production de vapeur Download PDF

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Publication number
WO1997045675A1
WO1997045675A1 PCT/EP1997/002954 EP9702954W WO9745675A1 WO 1997045675 A1 WO1997045675 A1 WO 1997045675A1 EP 9702954 W EP9702954 W EP 9702954W WO 9745675 A1 WO9745675 A1 WO 9745675A1
Authority
WO
WIPO (PCT)
Prior art keywords
ashes
process according
fuel
boiler
ash
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP1997/002954
Other languages
English (en)
Inventor
Alberto Carrea
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Magaldi Ricerche e Brevetti SRL
Original Assignee
Magaldi Ricerche e Brevetti SRL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Magaldi Ricerche e Brevetti SRL filed Critical Magaldi Ricerche e Brevetti SRL
Priority to AU30328/97A priority Critical patent/AU3032897A/en
Publication of WO1997045675A1 publication Critical patent/WO1997045675A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J1/00—Removing ash, clinker, or slag from combustion chambers
    • F23J1/02—Apparatus for removing ash, clinker, or slag from ash-pits, e.g. by employing trucks or conveyors, by employing suction devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • F23C9/06—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber for completing combustion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
    • F23J2900/01003—Ash crushing means associated with ash removal means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K2201/00—Pretreatment of solid fuel
    • F23K2201/50—Blending
    • F23K2201/501—Blending with other fuels or combustible waste
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/12—Heat utilisation in combustion or incineration of waste

Definitions

  • the present invention relates to a process for treating ashes which are generated by steam producing boilers. More particularly the present invention relates to a process readmitting the ashes into the combustion chamber, preferably by using an ash dry extraction apparatus.
  • the process according to the invention provides a considerable improvement of the efficiency of a coal dust or other solid fuel boiler when the bottom ashes which are there generated have a high unburnt percentage or contents.
  • the process includes a set of steps, which will be better disclosed in detail in the following, such steps allowing the bottom ashes which have been generated during the combustion step, to be recirculated to the fuel silos for a reintroduction thereof into the boiler.
  • the above second advantage makes the use of the present process convenient also when the unburnt matter contents of the bottom ashes is not high, thus providing a broader possibility of using such a process.
  • the ashes treatment could be simplified by introducing into the boiler also the bottom ashes, in view of their negligible effect on the operating conditions of both the combustion chamber and the downstream apparatus.
  • Claims 13-16 set forth particular embodiments of plants for carrying out the process according to the present invention.
  • FIG. 1 diagrammatically shows one plant embodiment which allows to carry out the process according to the invention
  • FIG. 2 diagrammatically shows a second plant embodiment which allows to carry out the process according to the invention
  • FIG. 3 diagramatically shows a third plant embodiment which allows to carry out the process according to the invention.
  • FIG. 4 diagrammatically shows a fourth plant embodiment which allows to carry out the process according to the invention.
  • the process according to the present invention is for use in steam producing boilers.
  • the process according to the present invention includes the following operations or main steps: a) dry extracting the ashes from the combustion chamber bottom and possibly cooling them to such temperatures which are compatible with the characteristics of the machinery which are in turn required and used for the further treating operations; b) crushing the ashes to a size which is compatible with the characteristics of the conveying system used for the ash recirculation, or with the fuel milling system, according to which of the above situations is more restrictive; and c) conveying the ashes from the discharge port of the crushing system to the fuel feeding silos for their reintroduction into the boiler.
  • the following apparatus and systems, according to the plant characteristics could be used.
  • the ash temperature at the extractor discharge port with respect to the temperature allowed by the downstream apparatus should be considered.
  • the dry extraction of the present process has the great advantage in respect of the wet systems that it allows the immediate reintroduction of the extracted bottom ashes into the fuel silos without having to remove water from the extracted material or to properly locate the ashes, for its drying in the open air.
  • the water contents of the wet ashes is in any case an energy loss because of the heat which will be taken away by the water evaporation.
  • a single crushing step (and for this purpose a single or double roller crusher could be used) or a double crushing step could be used in order to further reduce the ash size, if required by their output size (this situation could be when the ash conveying system to the silos is pneumatic-type).
  • the reintroduction of ashes into the combustion chamber be carried out according to the following criteria, i.e. that said reintroduction is carried out by solid fuel pulverization mills.
  • the proper time for reintroducing ashes into the fuel cycle could be chosen in the most suitable way according to the circumstances, complying with the configuration of the fresh fuel feeding system.
  • a possible way complying with such criteria is to mix the recycling ashes with the fresh fiiel on the belts feeding fuel to the fuel silos.
  • This system on the one hand provides a homogenous blend of the ashes and fuel, on the other hand needs some attention in order to avoid dust production when the dry and powdery ashes are discharged on the fresh fuel and further it requires that the system of feeding fresh fuel to the silos must be always operating.
  • the first problem dust production
  • the second problem will be solved by inserting, at the most convenient position, a storage tank which is able to contain the whole matter which is produced during the maximum stop time of the fresh fuel feeding apparatus.
  • the matter conveyance from the discharge port of the crushing system to said position could be carried out either by a mechanic apparatus or a conveying pneumatic one.
  • a possible change within the object of the present invention could be a process in which a very high crushing (pulverization) is carried out thus avoiding the use of fresh fuel mills in order to obtain such a pulverization (such an embodiment could be advantageous when the mills are considered a bottle-neck in the energy production).
  • the produced pulverized ashes could be introduced directly, by a pneumatic conveying system, into the feeding tubes of the mixture (primary air and fuel dust) upstream from the boilers.
  • a pneumatic conveying system design of the present process is extremely important whenever a temporary storing tank is interposed between two process apparatus (as it could be convenient in order to limit any charge peaks or discontinuously use the downstream conveying system as to limit its wear), particularly as far as the proper tank is concerned.
  • This is because of the inherent danger (due to the possible content of unbumt matter in the ashes) of causing a self combustion phenomenon which while it will not be hard because of the lack of flying matter into the ashes, is always a possible danger to be avoided.
  • Such temporary storing tanks will be missing or, if the plant design makes them preferable, they should be provided with an inerting system or should be so designed as to avoid the. above phenomena unless the matter dwell time being so short that the self combustion start will not be possible.
  • a further possible feature of the present invention which is of main importance, is the possibility of providing the system with an alternative path, possibly also to be used as a redundance conveying system, for discharging the matter from the recirculating circuit. While the experience teaches that the recirculate inert matter is like the inert fresh fuel (from the point of view of the percentage between bottom and light ashes) it is always advisable to provide a matter purge system whenever there is a progressive tendency of the recirculating matter to increase.
  • Such an alternative path could also be a simple matter discharge port and in such a case it should be placed, while in accordance with other requirements, in a position as upstream as possible in the system component sequence in order to use it also as a discharge port in emergency situations.
  • a plant 100 is shown using a belt extractor 18, a crusher 20 able to reduce the ash size to a size which is compatible with both the next conveying system and the pulverization solid fiiel system requirements and further a mechanical conveying system comprised of a cup elevator 24 and an ash wetting apparatus 28 which is used only in order to avoid dust at the extractor itself discharge port 26.
  • the wetting apparatus discharges the ashes directly on fresh fuel feeding belts 30, 32 in order to obtain a good mixing of fresh fuel and recirculated ashes. Starting from such a point the fresh fuel and ashes mix will travel along the usual feeding path toward the combustion chamber, firstly being discharged into the various silos 34.
  • 12 is a boiler provided with a proper (mechanic or hydraulic) seal, 14 a transition hopper, 16 a set of bottom valves, 22 a separator valve placed between the crusher and the cup elevator and 22A an emergency discharge port for valve 22.
  • FIG 2 a plant 200 similar to the above plant 100 is shown but further having a storage tank 36 for temporary storing ashes because the fresh fuel feeding apparatus is not continuously operating; such a storage tank 36 is provided with a proper inerting system 38 in order to eliminate the possible danger of ashes, burning or self burning.
  • the emergency discharge port is indicated by 36A because it is provided in the storage tank.
  • a storage tank extractor 22 is provided between the storage tank 36 and the cup elevator.
  • FIG. 3 a plant 300 using a pneumatic conveyor system 44 to reintroduce the ashes to silos 34 is shown; the system also uses a belt extractor 18 placed under the combustion chamber 12 and further a crusher 20 in order to reduce the ash size; a storage tank 36 of a proper volume provides a temporarv storing means for complying with the possible not continuous operation of the pneum: cic conveying apparatus, which indeed will operate discontinuously.
  • a further crusher 20A operates as a pneumatic transport feeder/batcher, such a further crusher is advisable when a further reduction of the ash size is required by the pneumatic conveyor apparatus (which is able to convey only not too large grains) requirements or whenever ash reaggregation into the storage tank 36 is possible, such a reaggregation will cause clogging of the pneumatic conveying system.
  • the pneumatic conveyance (which in such a case is a vacuum type one) provides the ash transport to a separator provided with a filter 42 for the de- pulverization of the transport air; the ashes will fall on the separator bottom from which they will be extracted (at the end of the pneumatic conveying step) by the wetting apparatus itself which has in such a case a dual function.
  • the wetting apparatus 28 will discharge the wet ashes on the belt feeding coal to silos.
  • FIG 4 a recirculating plant 400 is shown, such a plant being used whenever the dry ashes are collected in a hopper 14 placed under the combustion chamber and discontinuously evacuated therefrom and using a vacuum pneumatic conveying apparatus 44.
  • the hopper is evacuated according to a preset cycle, by using the crushing system (generally comprised of a number of parallel placed crushers 20) and the exhaustor 40 of the pneumatic conveying apparatus, from such a point the system is like the embodiment of the previous figure, where a set of ash admitting valves has been assigned the reference number 22.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Processing Of Solid Wastes (AREA)
  • Gasification And Melting Of Waste (AREA)

Abstract

Procédé permettant de traiter les cendres générées par les chaudières à production de vapeur. Fondamentalement, le procédé permet de réintroduire les cendres dans la chambre de combustion, de préférence au moyen d'un système d'extraction à sec des cendres, de type transporteur à courroie. Il réduit considérablement le pourcentage de matières imbrûlées dans les cendres, ce qui augmente le rendement de la chaudière et donne comme résultat final des cendres très fines qui sont plus faciles à traiter, à utiliser et à éliminer.
PCT/EP1997/002954 1996-05-31 1997-05-29 Procede pour recycler les cendres generees par les chaudieres a production de vapeur Ceased WO1997045675A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU30328/97A AU3032897A (en) 1996-05-31 1997-05-29 Process for recirculating ashes generated by steam producing boilers

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT96MI001114A IT1282773B1 (it) 1996-05-31 1996-05-31 Procedimento di ricircolo di ceneri prodotte da caldaie per la produzione di vapore
ITMI96A001114 1996-05-31

Publications (1)

Publication Number Publication Date
WO1997045675A1 true WO1997045675A1 (fr) 1997-12-04

Family

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Family Applications (1)

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PCT/EP1997/002954 Ceased WO1997045675A1 (fr) 1996-05-31 1997-05-29 Procede pour recycler les cendres generees par les chaudieres a production de vapeur

Country Status (3)

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AU (1) AU3032897A (fr)
IT (1) IT1282773B1 (fr)
WO (1) WO1997045675A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006005574A1 (fr) * 2004-07-09 2006-01-19 Magaldi Power S.P.A. Systeme integre servant a extraire des cendres lourdes, leur conversion en cendres legeres et reduction de matieres non brulees
WO2006013098A1 (fr) * 2004-08-06 2006-02-09 Magaldi Power S.P.A. Installation de transport mecanique a sec de pyrites et de poussier de charbon
WO2007104502A1 (fr) * 2006-03-13 2007-09-20 Magaldi Ricerche E Brevetti S.R.I. Système de broyage et de refroidissement air-eau du mâchefer provenant de fours de chauffage pour carburants solides
US7511013B2 (en) 2004-09-29 2009-03-31 Amr Technology, Inc. Cyclosporin analogues and their pharmaceutical uses
WO2009112328A2 (fr) 2008-03-03 2009-09-17 Clyde Bergemann Drycon Gmbh Système de recyclage des cendres
CN102269415A (zh) * 2011-04-26 2011-12-07 中国电力工程顾问集团西南电力设计院 一种省煤器灰的输送系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6146805A (ja) * 1984-08-11 1986-03-07 Kawasaki Heavy Ind Ltd オイルコ−クスの燃焼方法
EP0252967A1 (fr) 1986-01-10 1988-01-20 Mario Magaldi Appareil d'extraction a sec et en continu de cendres du fond d'une chaudiere.
JPH01111107A (ja) * 1987-10-23 1989-04-27 Kawasaki Heavy Ind Ltd 未燃チャー再燃焼系を有するサイクロン石炭燃焼炉
WO1991013293A1 (fr) * 1990-03-02 1991-09-05 Mario Magaldi Systeme de decharge des cendres de fond provenant de chaudieres a production de vapeur
DE4312897C1 (de) * 1993-04-16 1994-07-07 Ver Energiewerke Ag Verfahren und Anordnung zur Verbrennung von Unverbranntem aus dem Verbrennungsprozeß eines kohlenstaub- und/oder biostoffgefeuerten Dampfkessels

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6146805A (ja) * 1984-08-11 1986-03-07 Kawasaki Heavy Ind Ltd オイルコ−クスの燃焼方法
EP0252967A1 (fr) 1986-01-10 1988-01-20 Mario Magaldi Appareil d'extraction a sec et en continu de cendres du fond d'une chaudiere.
JPH01111107A (ja) * 1987-10-23 1989-04-27 Kawasaki Heavy Ind Ltd 未燃チャー再燃焼系を有するサイクロン石炭燃焼炉
WO1991013293A1 (fr) * 1990-03-02 1991-09-05 Mario Magaldi Systeme de decharge des cendres de fond provenant de chaudieres a production de vapeur
EP0471055A1 (fr) 1990-03-02 1992-02-19 Mario Magaldi Systeme de decharge des cendres de fond provenant de chaudieres a production de vapeur.
DE4312897C1 (de) * 1993-04-16 1994-07-07 Ver Energiewerke Ag Verfahren und Anordnung zur Verbrennung von Unverbranntem aus dem Verbrennungsprozeß eines kohlenstaub- und/oder biostoffgefeuerten Dampfkessels

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 010, no. 207 (M - 500) 19 July 1986 (1986-07-19) *
PATENT ABSTRACTS OF JAPAN vol. 013, no. 334 (M - 855) 27 July 1989 (1989-07-27) *

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006005574A1 (fr) * 2004-07-09 2006-01-19 Magaldi Power S.P.A. Systeme integre servant a extraire des cendres lourdes, leur conversion en cendres legeres et reduction de matieres non brulees
AU2005261832B2 (en) * 2004-07-09 2010-04-01 Magaldi Power S.P.A. Integrated system for the extraction of heavy ash, conversion thereof into light ash and reduction of unburnt matter
RU2419742C2 (ru) * 2004-07-09 2011-05-27 Магальди Пауэр С.П.А. Комплексный способ преобразования всех зол, вырабатываемых паровым котлом, в летучие золы с уменьшенным содержанием недогоревшего вещества и система для переработки зол, производимых паровым котлом, таким способом
US8091491B2 (en) 2004-07-09 2012-01-10 Magaldi Power S.P.A. Integrated system for the extraction of heavy ash, conversion thereof into light ash and reduction of unburnt matter
WO2006013098A1 (fr) * 2004-08-06 2006-02-09 Magaldi Power S.P.A. Installation de transport mecanique a sec de pyrites et de poussier de charbon
US7511013B2 (en) 2004-09-29 2009-03-31 Amr Technology, Inc. Cyclosporin analogues and their pharmaceutical uses
WO2007104502A1 (fr) * 2006-03-13 2007-09-20 Magaldi Ricerche E Brevetti S.R.I. Système de broyage et de refroidissement air-eau du mâchefer provenant de fours de chauffage pour carburants solides
EA014566B1 (ru) * 2006-03-13 2010-12-30 МАГАЛЬДИ РИКЕРКЕ Э БРЕВЕТТИ С.р.Л. Система измельчения и воздушно-водяного охлаждения зольного остатка из нагревательных печей для твердых топлив
WO2009112328A2 (fr) 2008-03-03 2009-09-17 Clyde Bergemann Drycon Gmbh Système de recyclage des cendres
WO2009112328A3 (fr) * 2008-03-03 2010-10-21 Clyde Bergemann Drycon Gmbh Système de recyclage des cendres
CN102269415A (zh) * 2011-04-26 2011-12-07 中国电力工程顾问集团西南电力设计院 一种省煤器灰的输送系统
CN102269415B (zh) * 2011-04-26 2013-07-31 中国电力工程顾问集团西南电力设计院 一种省煤器灰的输送系统

Also Published As

Publication number Publication date
AU3032897A (en) 1998-01-05
ITMI961114A0 (it) 1996-05-31
IT1282773B1 (it) 1998-03-31
ITMI961114A1 (it) 1997-12-01

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