EP0003831A1 - Process for burning waste containing salt in a fluidized bed - Google Patents
Process for burning waste containing salt in a fluidized bed Download PDFInfo
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- EP0003831A1 EP0003831A1 EP79100508A EP79100508A EP0003831A1 EP 0003831 A1 EP0003831 A1 EP 0003831A1 EP 79100508 A EP79100508 A EP 79100508A EP 79100508 A EP79100508 A EP 79100508A EP 0003831 A1 EP0003831 A1 EP 0003831A1
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- Prior art keywords
- fluidized bed
- mass
- salt
- bed mass
- fluidized
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- 150000003839 salts Chemical class 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000002699 waste material Substances 0.000 title 1
- 239000000463 material Substances 0.000 claims description 18
- 238000002485 combustion reaction Methods 0.000 claims description 13
- 238000005243 fluidization Methods 0.000 abstract 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 17
- 239000004576 sand Substances 0.000 description 9
- 239000006004 Quartz sand Substances 0.000 description 8
- 239000010801 sewage sludge Substances 0.000 description 7
- 239000000446 fuel Substances 0.000 description 6
- 239000003513 alkali Substances 0.000 description 5
- 239000010802 sludge Substances 0.000 description 4
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 4
- 150000001805 chlorine compounds Chemical class 0.000 description 3
- 239000012717 electrostatic precipitator Substances 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 239000012065 filter cake Substances 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229910001514 alkali metal chloride Inorganic materials 0.000 description 1
- 229910052936 alkali metal sulfate Inorganic materials 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000010327 methods by industry Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000010841 municipal wastewater Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
- F23G5/30—Incineration of waste; Incinerator constructions; Details, accessories or control therefor having a fluidised bed
Definitions
- the invention relates to a process for the combustion of salt-laden residues in a fluidized bed furnace, in particular the combustion of sewage sludge loaded with salts.
- Residues especially sewage sludge, are burned in fluidized bed furnaces with a sand bed at temperatures above 800 ° C.
- the object of the invention is to operate the combustion of salt-laden, in particular alkali chloride and sulfate-laden residues in the fluidized bed furnace in such a way that continuous, undisturbed operation is economically achieved.
- the present invention relates to a process for the combustion of salt-laden residues in a fluidized bed at temperatures of 730 to 900 ° C and with the removal of fluidized bed material, which is characterized in that before reaching a salt concentration in the fluidized bed material, in which the fluidized bed material at Operating temperature bakes together, part of the fluidized bed mass is discharged and replaced by fresh fluidized material.
- the combustion of salt-laden residues is also guaranteed to be trouble-free and economical.
- it has proven useful to increase the salt content to only half the critical value and to replace approx. 10% of the fluidized bed mass - in most cases, the quartz sand. If the salinity in - The fluidized bed mass is still sufficiently far from the critical concentration, a continuous concentration measurement is not necessary, and fluctuations in the composition of the sludge are also not critical.
- the salt concentration in the fluidized bed mass continuously or discontinuously at intervals of 3 to 10 hours, preferably once per shift.
- the conductivity of a suspension from a certain amount of fluidized bed mass with a certain amount of water is a sufficiently precise measure of its salt concentration.
- the removal of a part of the fluidized bed mass is automated via a rotary valve depending on the analysis result, with a correspondingly large amount of fresh sand being added to the remaining fluidized bed mass, so that the salt concentration in the fluidized bed mass again reaches a low predetermined value for trouble-free operation.
- it has been found sufficient to periodically regenerate the fluidized bed mass when a predetermined salt concentration in the fluidized bed mass is reached for example by replacing 10% of the fluidized bed mass with a corresponding amount of fresh fluidized material, for example sand).
- the temperature in the fluidized bed is reduced.
- the salt concentration at which the fluidized bed mass must be partially renewed can thereby be increased and more economical operation can be achieved due to the lower consumption of eddy material.
- the afterburning temperature can be controlled by additional burners above the fluidized bed. This afterburning does not disturb the combustion in the fluidized bed.
- the temperature in the fluidized bed is approximately 650 to 730 ° C., preferably 700 to 730 ° C., while in the post-combustion zone it is set to approximately 850 ° C., preferably 850 to 870 ° C.
- This variant is particularly suitable for the combustion of sludge containing alkali chloride and sulfate, since the sulfates remain partly in the fluidized bed mass to be removed, while the chlorides essentially escape with the ash and are separated in the downstream electrostatic precipitator.
- different materials can be used as the fluidized bed material.
- quartz sand which is known per se, has proven successful in the present process.
- boiler ash from the combustion of hard coal in granular form is preferably used.
- This material offers further advantages over the use of quartz sand in the method according to the invention, e.g. B.
- the throughput of sewage sludge is significantly higher and less air is needed to whirl up.
- the low fluid bed density enables better burnout.
- kettle ash also has a lower reactivity compared to e.g. B. alkali chlorides and alkali sulfates as quartz sand.
- the pressed filter cake (sewage sludge) is pumped from a buffer tank via 1 into the fluidized bed furnace 2 and burned.
- the throughput is 3500 kg sewage sludge per hour with a solids content of approx. 10 to 12% with a grate area of approx. 7 m 2 .
- the non-combustible part consisting of ash and entrained salts, is largely discharged with the fluidizing air at 3, cooled and separated in the downstream electrostatic precipitator. It depends on the temperature in the fluidized bed, how much salt accumulates on the fluidized material and at what concentrations it cakes comes in the fluidized bed mass.
- the fuel is added at 4.
- the fuel supply is adjusted by the controller 5 so that the fluidized bed temperature does not exceed 730 ° C.
- the required flue gas temperature of 850 ° C is ensured by a temperature-controlled 6 additional fuel feed 7 in the furnace chamber.
- the required combustion air is sucked in by a radial blower 8 via mufflers, heated in the air preheater 9 and blown into the furnace 10 from below.
- the furnace pressure is regulated by a suction fan (not shown).
- Fluidized bed mass is withdrawn discontinuously in accordance with the salt load via the cellular wheel lock 11 and a trough chain conveyor 12.
- Fresh quartz sand is added at 13 by a pneumatic conveying device 14.
- the metering container 16 is filled via the time-controlled valve 15 and the sample is mixed via 17 in the vessel 18 with 1000 ml of distilled water 19 and the conductivity 20 of the suspension is measured. If the salt content is more than 5% by weight, about 10% of the fluidized bed is discharged via the rotary valve 11 and replaced by adding 13 new quartz sand.
- the logical connections are Valves with the process computer not shown, as well as known control and regulating devices for operating the furnace.
- the pressed filter cake (sewage sludge) is pumped from a buffer tank via 1 into the fluidized bed furnace 2 and burned.
- the throughput rate is at a grid area of about 7 m 2 4200 kg of sewage sludge per hour with a solids content of about 10 to 12 '%.
- the non-combustible part consisting of ash and entrained salts, is largely discharged with the fluidizing air at 3, cooled and separated in the downstream electrostatic precipitator. It depends on the temperature in the fluidized bed, how much salt accumulates on the fluidized material and from which concentrations there are accretions in the fluidized bed mass.
- the fuel is added at 4.
- the fuel supply is adjusted by the controller 5 so that the fluidized bed temperature does not exceed 730 ° C.
- the required flue gas temperature of 850 ° C is ensured by a temperature-controlled 6 additional fuel feed 7 in the furnace chamber.
- the required combustion air is sucked in by a radial blower 8 via mufflers, heated in the air preheater 9 and blown into the furnace 10 from below.
- the furnace pressure is regulated by a suction fan (not shown).
- Fluidized bed mass is discontinuously according to the salt load via the rotary valve 11 and one Trough chain conveyor 12 removed.
- Fresh kettle ash at 13 is added by a pneumatic conveying device 14.
- the metering container 16 is filled via the time-controlled valve 15 and the sample is mixed with 1000 ml of distilled water 19 in the vessel 18 via 17 and the conductivity 20 of the suspension is measured. If the salt content is more than 5% by weight, about 10% of the fluidized bed is discharged via the rotary valve 11 and replaced again by adding fresh kettle ash 13.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluidized-Bed Combustion And Resonant Combustion (AREA)
- Gasification And Melting Of Waste (AREA)
- Incineration Of Waste (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Verbrennung von salzbeladenen Rückständen in einem Wirbelbettofen, insbesondere die Verbrennung von mit Salzen beladenen Klärschlämmen.The invention relates to a process for the combustion of salt-laden residues in a fluidized bed furnace, in particular the combustion of sewage sludge loaded with salts.
Rückstände, insbesondere Klärschlämme, werden in Wirbelschichtöfen mit Sandbett bei Temperaturen von über 800°C verbrannt. Beim Verbrennen von Rückständen aus kommunalen Kläranlagen treten dabei kaum Probleme auf; muß dagegen der Schlamm aus Industriekläranlagen behandelt werden, treten an dem Ofen öfters Betriebsstörungen auf, weil aufgrund eines viel höheren Salzgehaltes (im Mittel häufig mehr als 10 % der Trockensubstanz) im Wirbelbett sich das Salz anreichert, es bei Temperaturen über 730°C zu einem Aufschmelzen des Salzes und zu Anbackungen und einem Sintern der Wirbelbettmasse kommen kann, und es in ungünstigen Fällen zu einem glasartigen Zusammenbacken kommt, was erhebliche Stillstands- und Ausfallzeiten wegen der Ausräumungsarbeiten zur Folge hat.Residues, especially sewage sludge, are burned in fluidized bed furnaces with a sand bed at temperatures above 800 ° C. There are hardly any problems when burning residues from municipal wastewater treatment plants; on the other hand, if the sludge from industrial sewage treatment plants has to be treated, malfunctions often occur in the furnace, because due to a much higher salt content (on average often more than 10% of the dry matter) in the fluidized bed, the salt accumulates at temperatures above 730 ° C Melting of the salt and caking and sintering of the fluidized bed mass can occur and, in unfavorable cases, glass-like caking occurs, which results in considerable downtimes and downtimes due to the removal work.
Die Salze in den Schlämmen bestehen zum größten Teil aus Alkalichloriden und -sulfaten. Dabei hat sich gezeigt, daß bei einer Gesamtsalzbelastung der Wirbelbettmasse von 10 Gew.-% bei 800°C und Quarzsand als Wirbelgut kein störungsfreier Betrieb des Ofens mehr möglich ist.Most of the salts in the sludge consist of alkali chlorides and sulfates. It has been shown that with a total salt load of 10% by weight of the fluidized bed material at 800 ° C. and quartz sand as fluidized material, trouble-free operation of the furnace is no longer possible.
Nach Verfahrenstechnik 9 (1975), Nr. 12, Seite 624 gibt es mehrere Wege, um auch anorganisch oder organisch belasteten Sondermüll, der beim Verbrennen zum Kleben oder Schmelzen neigt, im Wirbelbett zu behandeln, nämlich
- a) durch Anheben der Reaktionstemperatur, so daß die betreffenden Salze vollständig verdampfen,
- b) durch Absenken der Reaktionstemperatur bis unterhalb des Schmelzpunktes,
- c) durch Zugabe von Zuschlagstoffen, die die Schmelztemperatur anheben.
- a) by raising the reaction temperature so that the salts in question evaporate completely,
- b) by lowering the reaction temperature to below the melting point,
- c) by adding additives that raise the melting temperature.
Aus Chemie, Ingenieur, Technik, 41. Jahrgang 1969, Nr. 10, Seite 615 ff. ist es ferner bereits bekannt, bei Änderungen in der Kornverteilung des Wirbelbetts von Zeit zu Zeit Wirbelmasse aus dem Bett abzuführen oder neuen Sand zuzugeben.From Chemie, Ingenieur, Technik, 41st year 1969, No. 10, page 615 ff., It is also already known to remove eddy mass from the bed or to add new sand from time to time when the grain distribution of the fluidized bed changes.
Diese bekannten Wege sind jedoch insbesondere bei Schlämmen, die zum größten Teil Alkalichloride und -sulfate als Salz enthalten, wirtschaftlich nicht vertretbar und in der Regel zur Erzielung eines ungestörten Betriebes nicht gangbar.However, these known routes are not economically justifiable, in particular in the case of sludges which contain, for the most part, alkali metal chlorides and sulfates as salts, and are generally not practicable for achieving undisturbed operation.
Aufgabe der Erfindung ist es, die Verbrennung salzbeladener, insbesondere alkalichlorid- und -sulfatbeladene Rückstände im Wirbelschichtofen so zu betreiben, daß ein kontinuierlicher ungestörter Betrieb wirtschaftlich erreicht wird.The object of the invention is to operate the combustion of salt-laden, in particular alkali chloride and sulfate-laden residues in the fluidized bed furnace in such a way that continuous, undisturbed operation is economically achieved.
Gegenstand der vorliegenden Erfindung ist ein Verfahren zur Verbrennung von salzbeladenen Rückständen in einem Wirbelbett bei Temperaturen von 730 bis 900 °C und bei Abziehen von Wirbelbettmasse, das dadurch gekennzeichnet ist, daß vor Erreichen einer Salzkonzentration in der Wirbelbettmasse,-bei der die Wirbelbettmasse bei der Betriebstemperatur zusammenbäckt, ein Teil der Wirbelbettmasse ausgeschleust und durch frisches Wirbelgut ersetzt wird.The present invention relates to a process for the combustion of salt-laden residues in a fluidized bed at temperatures of 730 to 900 ° C and with the removal of fluidized bed material, which is characterized in that before reaching a salt concentration in the fluidized bed material, in which the fluidized bed material at Operating temperature bakes together, part of the fluidized bed mass is discharged and replaced by fresh fluidized material.
Wenn erfindungsgemäß dafür gesorgt wird, daß die kritische Salzkonzentration, bei der die Wirbelbettmasse bei Betriebstemperatur zusammenbäckt, nicht erreicht wird, ist auch die Verbrennung von salzbeladenen Rückständen störungsfrei und wirtschaftlich gewährleistet. In der Praxis hat es sich bewährt, den Salzgehalt größenordnungsmäßig nur auf den halben kritischen Wert ansteigen zu lassen und jeweils ca. 10 % der Wirbelbettmasse - in den meisten Fällen ist das Quarzsand - auszuwechseln. Wenn der Salzgehalt in - der Wirbelbettmasse noch hinreichend weit von der kritischen Konzentration entfernt ist, ist eine laufende Konzentrationsmessung-nicht erforderlich, auch Schwankungen der Zusammensetzung des Schlammes sind nicht kritisch. Um aber andererseits auch nicht zu wenig beladenen Sand unnötig auszutragen, ist es zweckmäßig, kontinuierlich oder diskontinuierlich in Abständen von 3 bis 10 Stunden, vorzugsweise einmal pro Schicht, die Salzkonzentration in der Wirbelbettmasse zu messen. Die Leitfähigkeit einer Suspension aus einer bestimmten Menge Wirbelbettmasse mit einer bestimmten Menge Wasser ist ein hinreichend genaues Maß für deren Salzkonzentration. In einer bevorzugten Ausführungsform der vorliegenden Erfindung wird die Entnahme eines Teils der Wirbelbettmasse über eine Zellenradschleuse in_Abhängigkeit vom Analysenergebnis automatisiert, wobei der restlichen Wirbelbettmasse eine entsprechend große Menge frischen Sandes hinzugefügt wird, so daß die Salzkonzentration in der Wirbelbettmasse wieder einen geringen vorgegebenen Wert erreicht, bei dem ein störungsfreier Betrieb möglich ist. Es hat sich in vielen Fällen als ausreichend herausgestellt, bei Erreichen einer vorgegebenen Salzkonzentration in der Wirbelbettmasse periodisch (indem beispielsweise 10 % der Wirbelbettmasse durch eine entsprechende Menge frischen Wirbelgutes, z.B. Sand, ersetzt werden), die Wirbelbettmasse zu regenerieren.If it is ensured according to the invention that the critical salt concentration at which the fluidized bed mass cakes at operating temperature is not reached, the combustion of salt-laden residues is also guaranteed to be trouble-free and economical. In practice, it has proven useful to increase the salt content to only half the critical value and to replace approx. 10% of the fluidized bed mass - in most cases, the quartz sand. If the salinity in - The fluidized bed mass is still sufficiently far from the critical concentration, a continuous concentration measurement is not necessary, and fluctuations in the composition of the sludge are also not critical. On the other hand, in order not to unnecessarily discharge sand that is not too heavily loaded, it is expedient to measure the salt concentration in the fluidized bed mass continuously or discontinuously at intervals of 3 to 10 hours, preferably once per shift. The conductivity of a suspension from a certain amount of fluidized bed mass with a certain amount of water is a sufficiently precise measure of its salt concentration. In a preferred embodiment of the present invention, the removal of a part of the fluidized bed mass is automated via a rotary valve depending on the analysis result, with a correspondingly large amount of fresh sand being added to the remaining fluidized bed mass, so that the salt concentration in the fluidized bed mass again reaches a low predetermined value for trouble-free operation. In many cases it has been found sufficient to periodically regenerate the fluidized bed mass when a predetermined salt concentration in the fluidized bed mass is reached (for example by replacing 10% of the fluidized bed mass with a corresponding amount of fresh fluidized material, for example sand).
Nach einer weiteren Ausführungsform des erfindungsgemäßen Verfahrens wird die Temperatur im Wirbelbett herabgesetzt. Die Salzkonzentration, bei der die Wirbelbettmasse teilweise erneuert werden muß, kann dadurch erhöht werden und durch den geringeren Wirbelgutverbrauch ein wirtschaftlicherer Betrieb erreicht werden. Die Nachverbrennungstemperatur kann durch zusätzliche Brenner oberhalb des Wirbelbettes gesteuert werden. Durch diese Nachverbrennung wird die Verbrennung im Wirbelbett nicht gestört. Bei dieser Variante beträgt die Temperatur im Wirbelbett etwa 650 bis 730 °C, vorzugsweise 700 bis 730 °C, während sie in der Nachverbrennungszone auf etwa 850°C, vorzugsweise 850 bis 870°C eingestellt wird. Diese Variante eignet sich insbesondere für die Verbrennung alkalichlorid- und sulfathaltiger Schlämme, da hierbei die Sulfate zum Teil in der abzuführenden Wirbelbettmasse verbleiben, während die Chloride im wesentlichen mit der Alsche entweichen und im nachgeschalteten Elektrofilter abgeschieden werden.According to a further embodiment of the method according to the invention, the temperature in the fluidized bed is reduced. The salt concentration at which the fluidized bed mass must be partially renewed can thereby be increased and more economical operation can be achieved due to the lower consumption of eddy material. The afterburning temperature can be controlled by additional burners above the fluidized bed. This afterburning does not disturb the combustion in the fluidized bed. In this variant, the temperature in the fluidized bed is approximately 650 to 730 ° C., preferably 700 to 730 ° C., while in the post-combustion zone it is set to approximately 850 ° C., preferably 850 to 870 ° C. This variant is particularly suitable for the combustion of sludge containing alkali chloride and sulfate, since the sulfates remain partly in the fluidized bed mass to be removed, while the chlorides essentially escape with the ash and are separated in the downstream electrostatic precipitator.
Bei dem erfindungsgemäßen Verfahren können verschiedene Materialien als Wirbelbettmasse eingesetzt werden. Gut bewährt hat sich bei dem vorliegenden Verfahren die an sich bekannte Verwendung von Quarzsand. Bevorzugt wird jedoch Kesselasche aus der Steinkohleverbrennung in granulierter Form eingesetzt. Dieses Material bietet gegenüber der Verwendung von Quarzsand bei dem erfindungsgemäßen Verfahren weitere Vorteile, z. B. ist der Durchsatz an Klärschlamm bedeutend höher und es wird weniger Luft zum Aufwirbeln gebraucht. Ferner ermöglicht die niedrige Fließbettdichte einen besseren Ausbrand. Insbesondere weist Kesselasche auch eine geringere Reaktionsfähigkeit gegenüber z. B. Alkalichloriden und Alkalisulfaten als Quarzsand auf. Obwohl die Dichten von Kesselasche und Sand nahezu identisch sind, unterscheiden sich die Schüttgutdichten. Ungemahlene Kesselasche hat mit 1350 kg/m3 und gemahlene Kesselasche mit 1230 kg/m3 eine erheblich niedrigere Schüttgutdichte als Sand mit 1550 kg/m3. Diese Kesselasche besitzt jedoch ein größeres Hohlraumvolumen und ein nicht.vollständiges Umhüllen der unregelmäßig geformten Kesselascheteilchen erhöht das Hohlraumvolumen weniger als bei Sand. Dadurch tritt auch bei längerer Betriebszeit nur eine geringfügige Steigerung der Lockerungsgeschwindigkeit auf. Des weiteren steht Kesselasche günstiger als Sand ein.In the method according to the invention, different materials can be used as the fluidized bed material. The use of quartz sand, which is known per se, has proven successful in the present process. However, boiler ash from the combustion of hard coal in granular form is preferably used. This material offers further advantages over the use of quartz sand in the method according to the invention, e.g. B. The throughput of sewage sludge is significantly higher and less air is needed to whirl up. Furthermore, the low fluid bed density enables better burnout. In particular, kettle ash also has a lower reactivity compared to e.g. B. alkali chlorides and alkali sulfates as quartz sand. Although the densities of ash and sand are almost identical, the bulk densities differ. Unmilled kettle ash has 1350 kg / m 3 and milled kettle ash 1230 kg / m 3 a significantly lower bulk density than sand with 1550 kg / m 3 . However, this kettle ash has a larger void volume and an incomplete coating of the irregularly shaped kettle ash particles increases the void volume less than with sand. As a result, there is only a slight increase in the loosening speed even with a longer operating time. Furthermore, kettle ash is cheaper than sand.
Das erfindungsgemäße Verfahren ist in einem vereinfachten Schema in der Zeichnung dargestellt und wird im folgenden beispielhaft einmal mit Quarzsand und einmal mit Kesselasche als Wirbelbettmasse erläutert:The process according to the invention is shown in a simplified diagram in the drawing and is explained in the following by way of example once with quartz sand and once with kettle ash as a fluidized bed material:
Der gepreßte Filterkuchen (Klärschlamm) wird aus einem Pufferbehälter über 1 in den Wirbelschichtofen 2 eingepumpt und verbrannt. Die Durchsatzleistung beträgt bei einer Rostfläche von ca. 7 m2 3500 kg Klärschlamm pro Stunde mit einem Feststoffgehalt von ca. 10 bis 12 %. Der unbrennbare Anteil, bestehend aus Asche und mitgeführten Salzen, wird bei 3 zum größten Teil mit der Wirbelluft ausgetragen, abgekühlt und im nachgeschalteten Elektrofilter abgeschieden. Es hängt von der Temperatur im Wirbelbett ab, wieviel Salz sich am Wirbelgut ansammelt und ab welchen Konzentrationen es dabei .zu Anbackungen in der Wirbelbettmasse kommt. Der Brennstoff wird bei 4 zugegeben. Die Brennstoffzufuhr wird durch den Regler 5 so eingestellt, daß die Wirbelbett-Temperatur 730°C nicht überschreitet. Die erforderliche Rauchgastemperatur von 850°C wird durch eine temperaturgeregelte 6 Zusatzbrennstoffeinspeisung 7 im Ofenraum gewährleistet. Die erforderliche Verbrennungsluft wird durch ein Radialgebläse 8 über Schalldämpfer angesogen, im Luftvorwärmer 9 aufgeheizt und von unten 10 in den Ofen eingeblasen. Der Ofendruck wird durch ein (nicht gezeichnetes) Saugzuggebläse geregelt.The pressed filter cake (sewage sludge) is pumped from a buffer tank via 1 into the fluidized bed furnace 2 and burned. The throughput is 3500 kg sewage sludge per hour with a solids content of approx. 10 to 12% with a grate area of approx. 7 m 2 . The non-combustible part, consisting of ash and entrained salts, is largely discharged with the fluidizing air at 3, cooled and separated in the downstream electrostatic precipitator. It depends on the temperature in the fluidized bed, how much salt accumulates on the fluidized material and at what concentrations it cakes comes in the fluidized bed mass. The fuel is added at 4. The fuel supply is adjusted by the controller 5 so that the fluidized bed temperature does not exceed 730 ° C. The required flue gas temperature of 850 ° C is ensured by a temperature-controlled 6 additional fuel feed 7 in the furnace chamber. The required combustion air is sucked in by a
Wirbelbettmasse wird entsprechend der Salzbeladung diskontinuierlich über die Zellenradschleuse 11 und einen Trogkettenförderer 12 abgezogen. Die Zugabe von frischem Quarzsand bei 13 erfolgt durch eine pneumatische Fördereinrichtung 14.Fluidized bed mass is withdrawn discontinuously in accordance with the salt load via the
Es hat sich in diesem Beispiel als ausreichend herausgestellt, wenn für die Messung der Salzbeladung alle 2 Stunden, entweder manuell oder automatisch, ca. 100 g des Wirbelbettgutes entnommen werden. Über das zeitgesteuerte Ventil 15 wird der Dosierbehälter 16 gefüllt und die Probe über 17 in dem Gefäß 18 mit 1000 ml destilliertem Wasser 19 vermischt und die Leitfähigkeit 20 der Suspension gemessen. Beträgt der Salzgehalt mehr als 5 Gew.-%, so werden über die Zellenradschleuse 11 ca. 10 % des Wirbelbettes ausgetragen und durch Zugabe von frischem Quarzsand über 13 wieder ersetzt. Im Verfahrensschema in der Figur sind die logischen Verbindungen der Ventile mit dem Prozeßrechner nicht dargestellt, ebensowenig wie bekannte Steuer- und Regeleinrichtungen zum Betrieb des Ofens.In this example, it turned out to be sufficient if approximately 100 g of the fluidized bed material were removed every 2 hours, either manually or automatically, for measuring the salt load. The metering container 16 is filled via the time-controlled
Der gepreßte Filterkuchen (Klärschlamm) wird aus einem Pufferbehälter über 1 in den Wirbelschichtofen 2 eingepumpt und verbrannt. Die Durchsatzleistung beträgt bei einer Rostfläche von ca. 7 m2 4200 kg Klärschlamm pro Stunde mit einem Feststoffgehalt von ca. 10 bis 12' %. Der unbrennbare Anteil, bestehend aus Asche und mitgeführten Salzen, wird bei 3 zum größten Teil mit der Wirbelluft ausgetragen, abgekühlt und im nachgeschalteten Elektrofilter abgeschieden. Es hängt von der Temperatur im Wirbelbett ab, wieviel Salz sich am Wirbelgut ansammelt und ab welchen Konzentrationen es dabei zu Anbactungen in der Wirbelbettmasse kommt. Der Brennstoff wird bei 4 zugegeben. Die Brennstoffzufuhr wird durch den Regler 5 so eingestellt, daß die Wirbelbett-Temperatur 730°C nicht überschreitet. Die erforderliche Rauchgastemperatur von 850°C wird durch eine temperaturgeregelte 6 Zusatzbrennstoffeinspeisung 7 im Ofenraum gewährleistet. Die erforderliche Verbrennungsluft wird durch ein Radialgebläse 8 über Schalldämpfer angesogen, im Luftvorwärmer 9 aufgeheizt und von unten 10 in den Ofen eingeblasen. Der Ofendruck wird durch ein (nicht gezeichnetes) Saugzuggebläse geregelt.The pressed filter cake (sewage sludge) is pumped from a buffer tank via 1 into the fluidized bed furnace 2 and burned. The throughput rate is at a grid area of about 7 m 2 4200 kg of sewage sludge per hour with a solids content of about 10 to 12 '%. The non-combustible part, consisting of ash and entrained salts, is largely discharged with the fluidizing air at 3, cooled and separated in the downstream electrostatic precipitator. It depends on the temperature in the fluidized bed, how much salt accumulates on the fluidized material and from which concentrations there are accretions in the fluidized bed mass. The fuel is added at 4. The fuel supply is adjusted by the controller 5 so that the fluidized bed temperature does not exceed 730 ° C. The required flue gas temperature of 850 ° C is ensured by a temperature-controlled 6 additional fuel feed 7 in the furnace chamber. The required combustion air is sucked in by a
Wirbelbettmasse wird entsprechend der Salzbeladung diskontinuierlich über die Zellenradschleuse 11 und einen Trogkettenförderer 12 abgezogen. Die Zugabe von frischer Kesselasche bei 13 erfolgt durch eine pneumatische Fördereinrichtung 14.Fluidized bed mass is discontinuously according to the salt load via the
Es hat sich in diesem Beispiel als ausreichend herausgestellt, wenn für die Messung der Salzbeladung alle 8-10 Stunden, entweder manuell oder automatisch, ca. 100 g des Wirbelbettgutes entnommen werden. Über das zeitgesteuerte Ventil 15 wird der Dosierbehälter 16 gefüllt und die Probe über 17 in dem Gefäß 18 mit 1000 ml destilliertem Wasser 19 vermischt und die Leitfähigkeit 20 der Suspension gemessen. Beträgt der Salzgehalt mehr als 5 Gew.-%, so werden über die Zellenradschleuse 11 ca. 10 % des Wirbelbettes ausgetragen und durch Zugabe von frischer Kesselasche über 13 wieder ersetzt.In this example, it turned out to be sufficient if approximately 100 g of the fluidized bed material were removed every 8-10 hours, either manually or automatically, for measuring the salt load. The metering container 16 is filled via the time-controlled
Claims (6)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2808029 | 1978-02-24 | ||
DE19782808029 DE2808029A1 (en) | 1978-02-24 | 1978-02-24 | COMBUSTION OF SALT-LOADED RESIDUES IN A FLIPPED BED |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0003831A1 true EP0003831A1 (en) | 1979-09-05 |
EP0003831B1 EP0003831B1 (en) | 1980-10-29 |
Family
ID=6032868
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP79100417A Withdrawn EP0003792A3 (en) | 1978-02-24 | 1979-02-13 | Process for burning waste containing salt in a fluidized bed |
EP79100508A Expired EP0003831B1 (en) | 1978-02-24 | 1979-02-21 | Process for burning waste containing salt in a fluidized bed |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP79100417A Withdrawn EP0003792A3 (en) | 1978-02-24 | 1979-02-13 | Process for burning waste containing salt in a fluidized bed |
Country Status (2)
Country | Link |
---|---|
EP (2) | EP0003792A3 (en) |
DE (2) | DE2808029A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0087195A2 (en) * | 1982-02-18 | 1983-08-31 | Unilever N.V. | Method for processing of by-products of the refining of oils and fats |
WO1985002898A1 (en) * | 1983-12-24 | 1985-07-04 | Johan Roos | Combustion oven and process for producing fuel from refuse |
DE3604318A1 (en) * | 1986-02-12 | 1987-08-13 | Metallgesellschaft Ag | METHOD FOR BURNING COW MIST |
DE3733831A1 (en) * | 1987-10-07 | 1989-04-20 | Saarbergwerke Ag | Process for burning organic substances such as domestic waste, industrial waste and the like, using a fluidised-bed furnace |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3712801A1 (en) | 1987-04-15 | 1988-11-03 | Babcock Werke Ag | METHOD FOR BURNING INSB. SALTY BROWN COAL |
FR2710967B1 (en) * | 1993-10-05 | 1995-12-29 | Fm Ind | Method and unit for the treatment by calcination of hazardous waste. |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2416598A1 (en) * | 1973-06-25 | 1975-01-16 | Coal Industry Patents Ltd | PROCESS FOR BURNING STICKY OR HIGHLY VISCOSE SUBSTANCES IN A FLOATING BED MADE OF INERT OR CATALYTIC MATERIAL |
US3864458A (en) * | 1973-06-11 | 1975-02-04 | Dorr Oliver Inc | Fluid bed incineration of chloride-containing waste streams |
DE2338432A1 (en) * | 1973-07-28 | 1975-02-13 | Metallgesellschaft Ag | SLUDGE BURNING |
DE2402517A1 (en) * | 1974-01-19 | 1975-07-31 | Uhde Gmbh Friedrich | Thermal treatment of impure salt solns. - using a recycle of salt from a fluid bed to the gas space with additional milling |
US3907674A (en) * | 1974-04-24 | 1975-09-23 | Dorr Oliver Inc | Fluid bed incineration of wastes containing alkali metal chlorides |
US4038188A (en) * | 1975-03-14 | 1977-07-26 | The Dow Chemical Company | Method for preventing eutectic caking of sodium chloride at high temperatures |
US4071612A (en) * | 1974-10-15 | 1978-01-31 | Friedrich Uhde Gmbh | Process for the incineration of contaminated salt-bearing solutions |
-
1978
- 1978-02-24 DE DE19782808029 patent/DE2808029A1/en not_active Withdrawn
-
1979
- 1979-02-13 EP EP79100417A patent/EP0003792A3/en not_active Withdrawn
- 1979-02-21 DE DE7979100508T patent/DE2960032D1/en not_active Expired
- 1979-02-21 EP EP79100508A patent/EP0003831B1/en not_active Expired
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3864458A (en) * | 1973-06-11 | 1975-02-04 | Dorr Oliver Inc | Fluid bed incineration of chloride-containing waste streams |
DE2416598A1 (en) * | 1973-06-25 | 1975-01-16 | Coal Industry Patents Ltd | PROCESS FOR BURNING STICKY OR HIGHLY VISCOSE SUBSTANCES IN A FLOATING BED MADE OF INERT OR CATALYTIC MATERIAL |
DE2338432A1 (en) * | 1973-07-28 | 1975-02-13 | Metallgesellschaft Ag | SLUDGE BURNING |
DE2402517A1 (en) * | 1974-01-19 | 1975-07-31 | Uhde Gmbh Friedrich | Thermal treatment of impure salt solns. - using a recycle of salt from a fluid bed to the gas space with additional milling |
US3907674A (en) * | 1974-04-24 | 1975-09-23 | Dorr Oliver Inc | Fluid bed incineration of wastes containing alkali metal chlorides |
US4071612A (en) * | 1974-10-15 | 1978-01-31 | Friedrich Uhde Gmbh | Process for the incineration of contaminated salt-bearing solutions |
US4038188A (en) * | 1975-03-14 | 1977-07-26 | The Dow Chemical Company | Method for preventing eutectic caking of sodium chloride at high temperatures |
Non-Patent Citations (1)
Title |
---|
CHEMIE INGENIEUR TECHNIK, Vol. 41, Nr. 10, Mai 1969, Weinheim, E. ALBRECHT: "Schlammverbrennung im Wirbelschichtofen", Seiten 615-619. * |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0087195A2 (en) * | 1982-02-18 | 1983-08-31 | Unilever N.V. | Method for processing of by-products of the refining of oils and fats |
EP0096946A2 (en) * | 1982-02-18 | 1983-12-28 | Unilever N.V. | Method for processing of by-products of the refining of oils and fats |
EP0087195A3 (en) * | 1982-02-18 | 1984-05-16 | Unilever N.V. | Method for processing of by-products of the refining of oils and fats |
EP0096946A3 (en) * | 1982-02-18 | 1984-08-15 | Unilever N.V. | Method for processing of by-products of the refining of oils and fats |
WO1985002898A1 (en) * | 1983-12-24 | 1985-07-04 | Johan Roos | Combustion oven and process for producing fuel from refuse |
DE3604318A1 (en) * | 1986-02-12 | 1987-08-13 | Metallgesellschaft Ag | METHOD FOR BURNING COW MIST |
US4747356A (en) * | 1986-02-12 | 1988-05-31 | Metallgesellschaft Ag | Process of burning cattle dung |
DE3733831A1 (en) * | 1987-10-07 | 1989-04-20 | Saarbergwerke Ag | Process for burning organic substances such as domestic waste, industrial waste and the like, using a fluidised-bed furnace |
Also Published As
Publication number | Publication date |
---|---|
DE2960032D1 (en) | 1981-01-29 |
DE2808029A1 (en) | 1979-08-30 |
EP0003792A3 (en) | 1979-10-03 |
EP0003831B1 (en) | 1980-10-29 |
EP0003792A2 (en) | 1979-09-05 |
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