EP0000698A1 - Apparatus for preparing hexagonal phosphorous pentoxide - Google Patents

Apparatus for preparing hexagonal phosphorous pentoxide Download PDF

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EP0000698A1
EP0000698A1 EP7878100295A EP78100295A EP0000698A1 EP 0000698 A1 EP0000698 A1 EP 0000698A1 EP 7878100295 A EP7878100295 A EP 7878100295A EP 78100295 A EP78100295 A EP 78100295A EP 0000698 A1 EP0000698 A1 EP 0000698A1
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cooling
combustion chamber
chamber
condensation chamber
phosphorus pentoxide
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German (de)
French (fr)
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EP0000698B1 (en
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Gerhard Dr. Hartlapp
Werner Kowalski
Robert Queck
Theo Dahmen
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Hoechst AG
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Hoechst AG
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00Phosphorus; Compounds thereof
    • C01B25/12Oxides of phosphorus

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  • the present invention relates to a device for producing hexagonal phosphorus pentoxide, consisting of a water-cooled combustion chamber for phosphorus, which is followed by a cooled condensation chamber for the hexagonal phosphorus pentoxide (P 4 0 10 ).
  • Phosphorus pentoxide occurs in several solid modifications.
  • the hexagonal shape is used almost exclusively for technical purposes.
  • the polymeric glass-like modifications are inert and therefore entirely undesirable.
  • phosphorus pentoxide is obtained by burning elemental yellow phosphorus.
  • the resulting phosphorus pentoxide vapor is condensed on cooled surfaces.
  • this method has been carried out using devices which consist of a combustion chamber equipped with a phosphorus combustion nozzle and which is cooled from the outside by sprinkling with water.
  • This combustion chamber is connected to a condensation chamber which carries an exhaust pipe and a discharge device for P 2 O 5 (US Pat. No. 1,700,708).
  • this device has the disadvantage that it is not possible to produce hexagonal P205 in a targeted manner since part of the F 2 O 5 formed is already condensed in the combustion chamber. Since this condensation takes place within a very wide temperature range, products are obtained which consist of a mixture of the various modifications of P 2 O 5 .
  • DT-PS 1 300 527 It is also known from DT-PS 1 300 527 to use a device for the simultaneous production of hexagonal phosphorus pentoxide and polyphosphoric acid, which consists of a cooled combustion chamber, which at the same time represents the condensation chamber for the P 2 O 5 , which is connected via an exhaust pipe with a reaction tower Connection is established in which the exhaust gases of the combined combustion / condensation chamber are absorbed by circulating phosphoric acid to form polyphosphoric acid.
  • the devices used to carry out the known methods also have the disadvantage in common that direct heat transfer by radiation from the very hot phosphor flame to material already deposited cannot be prevented. In a short time, this leads to an at least partial conversion of the crystalline P 2 O 5 into glassy products.
  • a device for the production of hexagonal phosphorus pentoxide which consists of a coolable combustion chamber 1 which is equipped with a two-component combustion nozzle 2 for elementary phosphorus and one via a shut-off device 7 with a Collection container 8 for phosphorus pentoxide connected condensation chamber 4 is connected downstream, which carries an exhaust pipe 9.
  • This preferably horizontally arranged combustion chamber 1 is provided on its inner wall with cooling tubes 10 and connected to the condensation chamber 4 via a gas cooler 3, the gas cooler 3 consisting of a cooling tube system 5 , which ends in the manner of an open dip tube above the bottom of the condensation chamber 4, the walls of which are provided with a cooling device 6.
  • the cooling tubes 10 in the combustion chamber 1 and the cooling tube system 5 of the gas cooler 3 advantageously consist of spiral-wound tube bundles, which are expediently made of stainless steel.
  • condensation chamber 4 and gas cooler 3 are dimensioned such that the diameter of the condensation chamber 4 is a multiple of the diameter of the cascooler 3.
  • FIG. 1 A preferred embodiment of the device according to the invention is shown schematically in FIG. 1 below.
  • FIG. 2 shows an enlarged section which shows the deposition of the polymeric phosphorus pentoxide in the gussets formed by the tubes 5.
  • the combustion chamber 1 in which yellow phosphorus is burned in a two-substance nozzle 2 with a gas containing O 2 , consists of several sections of water-cooled stainless steel tubes 10 with an outer protective jacket.
  • the use of a combustion chamber 1 consisting of tube bundles 10 has the advantage that intensive cooling is ensured in all sections of this chamber by the forced guidance of the cooling water.
  • x is deposited as a result of cooling glassy polymeric phosphoric p entoxid (P 2 0 5) in the interstices, forming the tubes together. This is desirable here because the cooling tubes underneath are protected by this layer.
  • the outside wall temperature of the cooled pipes can thus be kept below 100 ° C; on the other hand, the surface temperature of the protective layer made of (P205) x is approximately 650 ° C.
  • the temperatures in front of the phosphor nozzle reach up to 2000 ° C. These high temperatures ensure complete oxidation of the P 4 to P 4 0 10 and do not need to be reduced by using a large excess of air or oxygen.
  • the O 2 content in the exhaust gas can rather be reduced to near the stoichiometric value, preferably down to ⁇ 2% 0 2 . This is important for the later Ab separation of the P 4 0 10 from the gas flow because the separation is better, the less exhaust gas has to leave the condensation chamber 4 again.
  • the amount of exhaust gas can be further reduced and the degree of separation improved accordingly if the dry air usually used for combustion is enriched with pure oxygen to about 40 volume% O 2 .
  • the gaseous P 4 0 10 leaves the combustion chamber at a temperature of 800 to 900 ° C.
  • this hot gas flows through the spirally turned and water-cooled tube bundle 5 made of stainless steel, which is arranged vertically as an “immersion tube”.
  • Additional polymeric phosphorus pentoxide is deposited on the cooled pipe surface.
  • the 800 to 900 ° C hot gas from the combustion chamber 1 heats this layer up to approx. 650 ° C.
  • the (P 2 O 5 ) x starts to evaporate again.
  • the layer here on the wall of the first cooling section is in evaporation equilibrium with the hot gas flowing past from the combustion chamber, ie the layer only reaches a certain thickness. Following the course of the temperature, it is only weakly formed in the upper part of the cooling device 3 at the connection to the combustion chamber 1, only weakly with a falling temperature.
  • the gas containing P 4 0 10 is cooled from the combustion chamber 1 to a temperature of 650 to 400 ° C. It has then been cooled down to such an extent that it can be suddenly cooled to ⁇ 300 ° C. when it enters the condensation chamber 4.
  • this pre-cooling in which one separates the polymeric phosphorus pentoxides for the formation of the above-described equilibrium state, it is achieved that there are no transition states with condensation of other phosphorus pentoxide modifications in the subsequent condensation chamber 4, but that the P 4 O 10 is only reflected in the desired hexagonal modification.
  • the hexagonal product is then deposited on these cooled surfaces of the condensation chamber 4, which have a wall temperature of 100 ° C. It collects in the lower part of the condensation chamber 4 and is discharged into a collecting container 8 via a lock 7. Based on the phosphorus used, the yield of hexagonal F4010 is more than 90%.
  • the degree of separation can be increased to more than 94% by using a combustion gas which is enriched with oxygen up to approx. 40 volume% 0 2 .
  • the exhaust gas that emerges from the condensation chamber 4 through the nozzle 9 has a temperature of 100 to 120 ° C.
  • the relatively small amounts of exhaust gas which only have a minimal content of P 4 0 10 , can then be cleaned without great effort, if necessary, by washing with water, phosphoric acid or the like before they are passed into the atmosphere.
  • the advantage of the device according to the invention is essentially that it prevents the direct heat radiation of the phosphorus flame onto deposited P 2 O 5 and also enables a targeted cooling of the reaction product, with a relatively large temperature difference in and in a relatively small space in the first cooling phase the second phase in a relatively large space a relatively small temperature difference is achieved.
  • the gas containing F 4 O 10 expands into the cooled condensation chamber 4, which surrounds the cooling device 3 over a wide area, which results in a further sudden cooling of the gas.
  • Hexagonal loose P 4 0 10 settles on the cooled walls of the condensation chamber 4 .
  • Pneumatic tapping devices knock the product off the walls. It collects in the lower part. the condensation chamber 4. 355 kg of phosphorus pentoxide are discharged here every hour.
  • the product is free of suboxides, reacts spontaneously with water and is free of glass-like impurities in the polymeric form of P 2 O 5 .
  • the yield based on the elemental phosphorus used, is 91%.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
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Abstract

Die vorliegende Erfindung betrifft eine Vorrichtung zur Herstellung von hexagonalem Phosphorpentoxid, bestehend aus einer Verbrennungskammer (1), die an ihrer Innenwand mit Kühlrohren (10) versehen ist und ferner über einen Gaskühler (3) mit einer Kondensationskammer (4) in Verbindung steht, wobei der Gaskühler (3) aus einem Kühlrohrsystem (5) besteht, das in der Art eines offenen Tauchrohres oberhalb des Bodens der Kondensationskammer (4) endet, deren Wände mit einer Kühlvorrichtung (6) versehen sind.The invention relates to a device for producing hexagonal phosphorus pentoxide, consisting of a combustion chamber (1), which is provided with cooling tubes (10) on its inner wall and is also connected to a condensation chamber (4) via a gas cooler (3) the gas cooler (3) consists of a cooling pipe system (5) which ends in the manner of an open immersion pipe above the bottom of the condensation chamber (4), the walls of which are provided with a cooling device (6).

Description

Die vorliegende Erfindung betrifft eine Vorrichtung zur Herstellung von hexagonalem Phosphorpentoxid, bestehend aus einer wassergekühlten Verbrennungskammer für Phosphor, der eine gekühlte Kondensationskammer für das hexagonale Phosphorpentoxid (P4010) nachgeschaltet ist.The present invention relates to a device for producing hexagonal phosphorus pentoxide, consisting of a water-cooled combustion chamber for phosphorus, which is followed by a cooled condensation chamber for the hexagonal phosphorus pentoxide (P 4 0 10 ).

Phosphorpentoxid tritt in mehreren festen Modifikationen auf. Für technische Zwecke kommt fast ausschließlich die hexagonale Form zur Anwendung. Insbesondere die polymeren glasartigen Modifikationen sind reaktionsträge und darum durchweg unerwünscht.Phosphorus pentoxide occurs in several solid modifications. The hexagonal shape is used almost exclusively for technical purposes. In particular, the polymeric glass-like modifications are inert and therefore entirely undesirable.

Man gewinnt Phosphorpentoxid technisch durch Verbrennen von elementarem gelben Phosphor. Der entstehende Phosphorpentoxid-Dampf wird an gekühlten Flächen kondensiert.Technically, phosphorus pentoxide is obtained by burning elemental yellow phosphorus. The resulting phosphorus pentoxide vapor is condensed on cooled surfaces.

Zur Durchführung dieses Verfahrens benutzte man bislang Vorrichtungen, die aus einer mit einer Phosphorverbrennungsdüse bestückten Brennkammer bestehen, die durch Berieseln mit Wasser von außen gekühlt wird. Diese Brennkammer ist mit einen Kondensationsraum verbunden, der einen Abgasstutzen sowie eine Austragsvorrichtung für P2O5 trägt (US-PS 1 700 708). Diese Vorrichtung hat jedoch den Nachteil, daß damit eine gezielte Herstellung von hexagonalem P205 nicht möglich ist, da bereits in der Brennkammer ein Teil des entstandenen F2O5 kondensiert wird. Da diese Kondensation innerhalb eines sehr weiten Temperaturbereiches erfolgt, fallen dabei Produkte an, die aus einem Gemisch der verschiedenen Modifikationen des P2O5 bestehen.To date, this method has been carried out using devices which consist of a combustion chamber equipped with a phosphorus combustion nozzle and which is cooled from the outside by sprinkling with water. This combustion chamber is connected to a condensation chamber which carries an exhaust pipe and a discharge device for P 2 O 5 (US Pat. No. 1,700,708). However, this device has the disadvantage that it is not possible to produce hexagonal P205 in a targeted manner since part of the F 2 O 5 formed is already condensed in the combustion chamber. Since this condensation takes place within a very wide temperature range, products are obtained which consist of a mixture of the various modifications of P 2 O 5 .

Bekannt ist ferner aus der DT-PS 1 300 527 zur gleichzeitigen Herstellung von hexagonalem Phosphorpentoxid und Polyphosphorsäure eine Vorrichtung einzusetzen, die aus einer gekühlten Brennkammer besteht, welche gleichzeitig die Kondensationskammer für das P2O5 darstellt, die über eine Abgasleitung mit einem Reaktionsturm in Verbindung steht, in welchem die Abgase der kombinierten Brenn-/Kondensationskammer von im Kreislauf geführter Phosphorsäure unter Bildung von Polyphosphorsäure absorbiert werden.It is also known from DT-PS 1 300 527 to use a device for the simultaneous production of hexagonal phosphorus pentoxide and polyphosphoric acid, which consists of a cooled combustion chamber, which at the same time represents the condensation chamber for the P 2 O 5 , which is connected via an exhaust pipe with a reaction tower Connection is established in which the exhaust gases of the combined combustion / condensation chamber are absorbed by circulating phosphoric acid to form polyphosphoric acid.

Nachteilig an dieser Vorrichtung ist u.a., daß sie nur dann verwendbar ist, wenn die P205 - Herstellung mit der Gewinnung von Polyphosphorsäure gekoppelt ist.One disadvantage of this device is that it can only be used if the P205 production is coupled with the production of polyphosphoric acid.

Bekanntlich ist die Verbrennungswärme von elementarem Phosphor außerordentlich hoch. Damit an den Wänden der kombinierten Brenn-/Kondensationskammer eine Abscheidung von hexagonalem Phosphorpentoxid überhaupt erreicht werden kann, muß aufgrund der um die Phosphorverbrennungsdüse herum herrschenden hohen Temperaturen, die Kammer sehr groß dimensioniert sein und die Verbrennung des Phosphors mit einem großen Luftüberschuß (20 bis-50 Gewichts%) erfolgen. .It is known that the heat of combustion of elemental phosphorus is extremely high. In order for hexagonal phosphorus pentoxide to be deposited on the walls of the combined combustion / condensation chamber at all, the chamber must be very large due to the high temperatures prevailing around the phosphorus combustion nozzle and the combustion of the phosphorus with a large excess of air (20 to 50% by weight). .

Dies hat zur Folge, daß dabei zwangsläufig große Abgasmengen mit einer relativ hohen Temperatur (380 bis 410°C) anfallen, was aufwendige Absorptionsvorrichtungen notwendig macht, da in der Brenn-/Kondensationskammer nur etwa 43 % des entstandenen Phosphorpentoxides abgeschieden und. der Rest aus dieser Kammer ausgetragen wird.The consequence of this is that large amounts of exhaust gas with a relatively high temperature (380 to 410 ° C.) are inevitably produced, which necessitates complex absorption devices, since only about 43% of the phosphorus pentoxide formed is separated off and deposited in the combustion / condensation chamber. the rest is discharged from this chamber.

Insbesondere dann, wenn die Herstellung von Phosphorpentoxid nicht unmittelbar mit der Gewinnung von Ortho- oder Polyphosphorsäure gekoppelt ist, stellt dies sowohl verfahrenstechnisch als auch wirtschaftlich einen großen Nachteil dar.Particularly when the production of phosphorus pentoxide is not directly linked to the production of orthophosphoric or polyphosphoric acid, this represents a major disadvantage both in terms of process technology and economically.

Die zur Durchführung der bekannten Arbeitsweisen verwendeten Vorrichtungen haben außerdem den Nachteil gemeinsam, daß eine direkte Wäremübertragung durch Strahlung von der sehr heißen Phosphorflamme auf bereits abgeschiedenes Material nicht verhindert werden kann. Dies führt in kurzer Zeit zu einer zumindest teilweisen Umwandlung des kristallinen P2O5 in glasige Produkte.The devices used to carry out the known methods also have the disadvantage in common that direct heat transfer by radiation from the very hot phosphor flame to material already deposited cannot be prevented. In a short time, this leads to an at least partial conversion of the crystalline P 2 O 5 into glassy products.

Überraschenderweise wurde nun gefunden, daß sich diese Nachteile überwinden lassen, wenn man zur Herstellung von hexagonalem Phosphorpentoxid eine Vorrichtung einsetzt, die aus einer kühlbaren Verbrennungskammer 1 besteht, die mit einer Zweistoffverbrennungsdüse 2 für elementaren Phosphor bestückt ist und der eine über ein Absperrorgan 7 mit einem Auffangbehälter 8 für Phosphorpentoxid verbundene Kondensationskammer 4 nachgeschaltet ist, die einen Abgasstutzen 9 trägt.Diese vorzugsweise horizontal angeordnete Verbrennungskammer 1 ist an ihrer Innenwand mit Kühlrohren 10 versehen und über einen Gaskühler 3 mit der Kondensationskammer 4 verbunden, wobei der Gaskühler 3 aus einem Kühlrohrsystem 5 besteht, das in der Art eines offenen Tauchrohres oberhalb des Bodens der Kondensationskammer 4 endet, deren Wände mit einer Kühlvorrichtung 6 versehen sind.Surprisingly, it has now been found that these disadvantages can be overcome if a device is used for the production of hexagonal phosphorus pentoxide which consists of a coolable combustion chamber 1 which is equipped with a two-component combustion nozzle 2 for elementary phosphorus and one via a shut-off device 7 with a Collection container 8 for phosphorus pentoxide connected condensation chamber 4 is connected downstream, which carries an exhaust pipe 9. This preferably horizontally arranged combustion chamber 1 is provided on its inner wall with cooling tubes 10 and connected to the condensation chamber 4 via a gas cooler 3, the gas cooler 3 consisting of a cooling tube system 5 , which ends in the manner of an open dip tube above the bottom of the condensation chamber 4, the walls of which are provided with a cooling device 6.

Die Kühlrohre 10 in der Verbrennungskammer 1 und das Kühlrohrsystem 5 des Gaskühlers 3 bestehen vorteilhafterweise aus spiralförmig gewundenen Rohrbündeln, die zweckmäßigerweise aus Edelstahl gefertigt sind.The cooling tubes 10 in the combustion chamber 1 and the cooling tube system 5 of the gas cooler 3 advantageously consist of spiral-wound tube bundles, which are expediently made of stainless steel.

Wichtig ist auch, daß Kondensationskammer 4 und Gaskühler 3 so dimensioniert sind, daß der Durchmesser der Kondensationskammer 4 ein Mehrfaches des Durchmessers des Caskühlers 3 beträgt.It is also important that the condensation chamber 4 and gas cooler 3 are dimensioned such that the diameter of the condensation chamber 4 is a multiple of the diameter of the cascooler 3.

Durch die erfindungsgemäße Vorrichtung ergeben sich eine Reihe von Vorteilen:

  • 1) das erhaltene Produkt besteht aus der hexagonalen Form des P4010 und enthält keine polymeren Anteile;
  • 2) die Ausbeute beträgt mehr als 90 %;
  • 3) die Dimensionen der Anlage können relativ klein gehalten werden.
A number of advantages result from the device according to the invention:
  • 1) the product obtained consists of the hexagonal form of the P4010 and contains no polymer components;
  • 2) the yield is more than 90%;
  • 3) the dimensions of the system can be kept relatively small.

Eine bevorzugte Ausgestaltung der erfindungsgemäßen Vorrichtung ist in der nachfolgenden Figur 1 schematisch dargestellt.A preferred embodiment of the device according to the invention is shown schematically in FIG. 1 below.

Figur 2 zeigt einen vergrößerten Ausschnitt,der die Abscheidung des polymeren Phosphorpentoxides in den von den Rohren 5 gebildeten Zwickeln darstellt.FIG. 2 shows an enlarged section which shows the deposition of the polymeric phosphorus pentoxide in the gussets formed by the tubes 5.

Die Verbrennungskammer 1, in der gelber Phosphor in einer Zweistoffdüse 2 mit einem 02-haltigen Gas verbrannt wird, besteht aus mehreren Abschnitten wassergekühlter Edelstahlrohre 10 mit einem äußeren Schutzmantel. Die Verwendung einer aus Rohrbündeln 10 bestehenden Verbrennungskammer 1 hat den Vorteil, daß in allen Abschnitten dieser Kammer durch die Zwangsführung des Kühlwassers eine intensive Kühlung gewährleistet ist. An der Innenwand der Rohrbündel 10 wird in den Zwickeln, welche die Rohre miteinander bilden, infolge der Kühlung glasartiges polymeres Phosphor- pentoxid (P205)x abgeschieden. Dies ist hier erwünscht, weil durch diese Schicht die darunterliegenden Kühlrohre geschützt werden. Die Außenwandtemperatur der gekühlten Rohre läßt sich so unter 100°C halten; hingegen beträgt die Oberflächentemperatur der Schutzschicht aus (P205)x etwa 650°C. Die Temperaturen vor der Phosphordüse reichen bis zu 2000°C. Diese hohen Temperaturen gewährleisten eine vollständige Oxidation des P4 zu P4010 und brauchen nicht durch Verwendung eines großen Luft- bzw. Sauerstoffüberschusses herabgesetzt werden. Der O2-Gehalt im Abgas kann vielmehr bis nahe dem stöchiometrischen Wert, vorzugsweise bis auf ~ 2 % 02 gesenkt werden. Dies ist wichtig für die spätere Abscheidung des P4010 aus dem Gasstrom, weil die Abscheidung umso besser ist, je weniger Abgas die Kondensationskammer 4 wieder verlassen muß.The combustion chamber 1, in which yellow phosphorus is burned in a two-substance nozzle 2 with a gas containing O 2 , consists of several sections of water-cooled stainless steel tubes 10 with an outer protective jacket. The use of a combustion chamber 1 consisting of tube bundles 10 has the advantage that intensive cooling is ensured in all sections of this chamber by the forced guidance of the cooling water. On the inner wall of the tube bundle 10 is, x is deposited as a result of cooling glassy polymeric phosphoric p entoxid (P 2 0 5) in the interstices, forming the tubes together. This is desirable here because the cooling tubes underneath are protected by this layer. The outside wall temperature of the cooled pipes can thus be kept below 100 ° C; on the other hand, the surface temperature of the protective layer made of (P205) x is approximately 650 ° C. The temperatures in front of the phosphor nozzle reach up to 2000 ° C. These high temperatures ensure complete oxidation of the P 4 to P 4 0 10 and do not need to be reduced by using a large excess of air or oxygen. The O 2 content in the exhaust gas can rather be reduced to near the stoichiometric value, preferably down to ~ 2% 0 2 . This is important for the later Ab separation of the P 4 0 10 from the gas flow because the separation is better, the less exhaust gas has to leave the condensation chamber 4 again.

Die Abgasmenge kann weiter verringert, der Abscheidegrad entsprechend verbessert werden, wenn die gewöhnlich zur Verbrennung verwendete trockene Luft mit reinem Sauerstoff auf ca. 40 Volumen% O2 angereichert wird.The amount of exhaust gas can be further reduced and the degree of separation improved accordingly if the dry air usually used for combustion is enriched with pure oxygen to about 40 volume% O 2 .

Das gasförmige P4010 verläßt die Verbrennungskammer mit einer Temperatur von 800 bis 900°C.The gaseous P 4 0 10 leaves the combustion chamber at a temperature of 800 to 900 ° C.

In der Kühlvorrichtung 3 durchströmt dieses heiße Gas die vertikal als "Tauchrohr" angeordnete spiralförmige gedrehten und wassergekühlten Rohrbündel 5 aus Edelstahl.In the cooling device 3, this hot gas flows through the spirally turned and water-cooled tube bundle 5 made of stainless steel, which is arranged vertically as an “immersion tube”.

Hier spielt sich folgender Vorgang ab:The following process takes place here:

An der gekühlten Rohrfläche scheidet sich weiteres polymeres Phosphorpentoxid ab. Das 800 bis 900°C heiße Gas aus der Verbrennungskammer 1 erhitzt diese Schicht bis auf ca. 650°C. Bei dieser Temperatur beginnt das (P2O5)x wieder zu verdampfen. Die hier an der Wand des ersten Kühlabschnittes befindliche Schicht steht im Verdampfungsgleichgewicht mit dem vorbeistreichenden heißen Gas aus der Brennkammer, d.h. die Schicht erreicht nur eine bestimmte Stärke. Dem Temperaturverlauf folgend ist sie im oberen Teil der Kühlvorrichtung 3 an der Verbindung zur Verbrennungskammer 1, nur schwach, nach unten hin mit fallender Temperatur stärker ausgebildet.Additional polymeric phosphorus pentoxide is deposited on the cooled pipe surface. The 800 to 900 ° C hot gas from the combustion chamber 1 heats this layer up to approx. 650 ° C. At this temperature the (P 2 O 5 ) x starts to evaporate again. The layer here on the wall of the first cooling section is in evaporation equilibrium with the hot gas flowing past from the combustion chamber, ie the layer only reaches a certain thickness. Following the course of the temperature, it is only weakly formed in the upper part of the cooling device 3 at the connection to the combustion chamber 1, only weakly with a falling temperature.

In dieser Kühlvorrichtung 3 erfolgt die Abkühlung des P4010-haltigen Gases aus der Verbrennungskammer 1 auf eine Temperatur von 650 bis 400°C. Es ist dann soweit abgekühlt worden, daß es beim Eintritt in die Kondensationskammer 4 schlagartig auf< 300°C abgekühlt werden kann. Durch diese Vorkühlung,bei der man die Abscheidung des polymeren Fhosphorpentoxides zur Ausbildung des oben beschriebenen Gleichgewichtszustandes gezielt in Kauf nimmt, wird erreicht, daß es in der nachfolgenden Kondensationskammer 4 nicht zu Übergangszuständen mit Kondensationen von anderen Phosphorpentoxidmodifikationen kommt, sondern daß sich das P4O10 hier nur in der gewünschten hexagonalen Modifikation niederschlägt.In this cooling device 3, the gas containing P 4 0 10 is cooled from the combustion chamber 1 to a temperature of 650 to 400 ° C. It has then been cooled down to such an extent that it can be suddenly cooled to <300 ° C. when it enters the condensation chamber 4. By this pre-cooling, in which one separates the polymeric phosphorus pentoxides for the formation of the above-described equilibrium state, it is achieved that there are no transition states with condensation of other phosphorus pentoxide modifications in the subsequent condensation chamber 4, but that the P 4 O 10 is only reflected in the desired hexagonal modification.

An diesen gekühlten Flächen der Kondensationskammer 4, die einer Wandtemperatur von 100°C haben, schlägt sich dann das hexagonale Produkt nieder. Es sammelt sich im unteren Teil der Kondensationskammer 4 an und wird über eine Schleuse 7 in einen Auffangbehälter 8 ausgetragen. Bezogen auf den eingesetzten Phosphor'beträgt die Ausbeute an hexagonalem F4010 mehr als 90 %. Durch Verwendung eines Verbrennungsgases, das mit Sauerstoff bis ca. 40 Volumen% 02 angereichert ist, läßt sich der Abscheidegrad auf mehr als 94 % steigern. Das Abgas, das aus der Kondensationskammer 4 durch den Stutzen 9 austritt, besitzt eine Temperatur von 100 bis 120°C. Die relativ geringen Abgasmengen, die nur noch einen minimalen Gehalt an P4010 aufweisen, lassen sich dann ohne großen Aufwand, falls erforderlich, durch Waschen mit Wasser, Phosphorsäure oder dergleichen reinigen, bevor sie in die Atmosphäre geleitet werden.The hexagonal product is then deposited on these cooled surfaces of the condensation chamber 4, which have a wall temperature of 100 ° C. It collects in the lower part of the condensation chamber 4 and is discharged into a collecting container 8 via a lock 7. Based on the phosphorus used, the yield of hexagonal F4010 is more than 90%. The degree of separation can be increased to more than 94% by using a combustion gas which is enriched with oxygen up to approx. 40 volume% 0 2 . The exhaust gas that emerges from the condensation chamber 4 through the nozzle 9 has a temperature of 100 to 120 ° C. The relatively small amounts of exhaust gas, which only have a minimal content of P 4 0 10 , can then be cleaned without great effort, if necessary, by washing with water, phosphoric acid or the like before they are passed into the atmosphere.

Der Vorteil der erfindungsgemäßen Vorrichtung besteht also im wesentlichen darin, daß sie die direkte Wärmestrahlung der Phosphorflamme auf abgeschiedenes P2O5 verhindert und außerdem eine gezielte Abkühlung des Reaktionsproduktes ermöglicht, wobei in der ersten Abkühlungsphase in einem relativ kleinen Raum eine relativ große Temperaturdifferenz und in der zweiten Phase in einem relativ großen Raum eine relativ geringe Temperaturdifferenz erzielt wird.The advantage of the device according to the invention is essentially that it prevents the direct heat radiation of the phosphorus flame onto deposited P 2 O 5 and also enables a targeted cooling of the reaction product, with a relatively large temperature difference in and in a relatively small space in the first cooling phase the second phase in a relatively large space a relatively small temperature difference is achieved.

Beispielexample

Pro Stunde werden 100 1 (170 kg) elementarer, flüssiger, gelber Phosphor von ca. 75°C in einer Brennkammer 1, deren gekühlte Wände aus Edelstahlrohrbündeln 10 bestehen, mit trockener Luft von 5,0 bar verbrannt. Die 02-Bestimmung im Abgas ergibt einen Wert von 2,0 % 02. Das P4O10- haltige Gas wird mit einer Temperatur von 900°C in die Gaskühlvorrichtung 3, die ebenfalls aus wassergekühlten Bündeln von Edelstahlrohren 5 besteht, geleitet. An deren Wänden setzt sich polymeres Phosphorpentoxid ab. Dadurch wird der Anfang der Kühlvorrichtung 3 soweit isoliert, daß die Temperatur des glasartigen Belages auf deren Wand auf ca. 650°C steigt. Zum Ende des Kühlrohres nimmt die Temperatur des Belages bis auf 400°C ab.100 1 (170 kg) of elementary, liquid, yellow phosphorus of approx. 75 ° C. per hour are burned in a combustion chamber 1, the cooled walls of which consist of stainless steel tube bundles 10, with dry air of 5.0 bar. The 0 2 determination in the exhaust gas gives a value of 2.0% 0 2 . The P 4 O 10 -containing gas is conducted at a temperature of 900 ° C. into the gas cooling device 3, which also consists of water-cooled bundles of stainless steel tubes 5. Polymeric phosphorus pentoxide is deposited on the walls. As a result, the beginning of the cooling device 3 is insulated to such an extent that the temperature of the glass-like coating on its wall rises to approximately 650 ° C. At the end of the cooling pipe, the temperature of the coating drops to 400 ° C.

Das F4O10-haltige Gas expandiert in die gekühlte Kondensationskammer 4, welche die Kühlvorrichtung 3 weiträumig umschließt, was eine weitere schlagartige Abkühlung des Gases zur Folge hat. An den gekühlten Wänden der Kondensationskammer 4 setzt sich hexagonales lockeres P4010 ab. Mit Hilfe pneumatischer Klopfvorrichtungen wird das Produkt von den Wänden abgeklopft. Es sammelt sich im unteren Teil. der Kondensationskammer 4. Stündlich werden hier 355 kg Phosphorpentoxid ausgetragen. Das Produkt ist frei von Suboxiden, reagiert spontan mit Wasser und ist frei von glasartigen Verunreinigungen der polymeren Form des P2O5.The gas containing F 4 O 10 expands into the cooled condensation chamber 4, which surrounds the cooling device 3 over a wide area, which results in a further sudden cooling of the gas. Hexagonal loose P 4 0 10 settles on the cooled walls of the condensation chamber 4 . Pneumatic tapping devices knock the product off the walls. It collects in the lower part. the condensation chamber 4. 355 kg of phosphorus pentoxide are discharged here every hour. The product is free of suboxides, reacts spontaneously with water and is free of glass-like impurities in the polymeric form of P 2 O 5 .

Die Ausbeute, bezogen auf den eingesetzten elementaren Phosphor, beträgt 91 %.The yield, based on the elemental phosphorus used, is 91%.

Claims (5)

1. Vorrichtung zur Herstellung von Phosphorpentoxid, bestehend aus einer kühlbaren Verbrennungskammer (1), die mit einer Zweistoffverbrennungsdüse (2) für elementaren Phosphor bestückt und der eine über ein Absperrorgan (7) mit einem Auffangbehälter (8) für Phosphorpentoxid verbundene Kondensationskammer (4) nachgeschaltet ist, die einen Abgasstutzen (9) trägt, dadurch gekennzeichnet, daß zur Herstellung von hexagonalem Phosphorpentoxid die Verbrennungskammer (1) an ihrer Innenwand mit Kühlrohren (10) versehen ist,und daß die Verbrennungskammer (1) über einen Gaskühler (3) mit der Kondensationskammer (4) in Verbindung steht, wobei der Gaskühler (3) aus einem Kühlrohrsystem (5) besteht, das in der Art eines offenen Tauchrohres oberhalb des Bodens der Kondensationskammer (4) endet, deren Wände mit einer Kühlvorrichtung (6) versehen sind.1. Device for the production of phosphorus pentoxide, consisting of a coolable combustion chamber (1) which is equipped with a two-substance combustion nozzle (2) for elementary phosphorus and which has a condensation chamber (4) connected via a shut-off device (7) with a collecting container (8) for phosphorus pentoxide. is connected downstream, which carries an exhaust pipe (9), characterized in that for the production of hexagonal phosphorus pentoxide, the combustion chamber (1) is provided on its inner wall with cooling tubes (10), and that the combustion chamber (1) is provided with a gas cooler (3) is connected to the condensation chamber (4), the gas cooler (3) consisting of a cooling pipe system (5) which ends in the manner of an open immersion pipe above the bottom of the condensation chamber (4), the walls of which are provided with a cooling device (6) . 2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet,daß die Verbrennungskammer (1) horizontal angeordnet ist.2. Device according to claim 1, characterized in that the combustion chamber (1) is arranged horizontally. 3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Kühlrohre (10) in der Verbrennungskammer (1) und das Kühlrohrsystem (5) des Gaskühlers (3) aus spiralförmig gewundenen 'Rohrbündeln besteht.3. Apparatus according to claim 1 or 2, characterized in that the cooling tubes (10) in the combustion chamber (1) and the cooling tube system (5) of the gas cooler (3) consists of spirally wound 'tube bundles. 4. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß die Rohrbündel aus Edelstahl gefertigt sind.4. The device according to claim 3, characterized in that the tube bundle are made of stainless steel. 5. Vorrichtung nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der Durchmesser der Kondensationskammer (4) ein Mehrfaches des Durchmessers des Gaskühlers (3) beträgt.5. Device according to one of claims 1 to 4, characterized in that the diameter of the condensation chamber (4) is a multiple of the diameter of the gas cooler (3).
EP78100295A 1977-08-16 1978-07-03 Apparatus for preparing hexagonal phosphorous pentoxide Expired EP0000698B1 (en)

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DE19772736765 DE2736765A1 (en) 1977-08-16 1977-08-16 DEVICE FOR MANUFACTURING HEXAGONAL PHOSPHORUS PENTOXIDE
DE2736765 1977-08-16

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EP0000698A1 true EP0000698A1 (en) 1979-02-21
EP0000698B1 EP0000698B1 (en) 1981-08-05

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CA (1) CA1097034A (en)
DE (2) DE2736765A1 (en)
IT (1) IT1106883B (en)

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EP0242678A2 (en) * 1986-04-25 1987-10-28 Hoechst Aktiengesellschaft Process for the preparation of phosphorus pentoxide with reduced reactivity

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DE3033109A1 (en) * 1980-09-03 1982-04-22 Hoechst Ag, 6000 Frankfurt METHOD FOR PRODUCING PHOSPHOROXIDE OXIDE USING THE REACTION HEAT
DE3315630A1 (en) * 1983-04-29 1984-10-31 Hoechst Ag, 6230 Frankfurt METHOD AND DEVICE FOR PRODUCING PHOSPHOROXIDE OXIDE USING THE REACTION HEAT
US4713228A (en) * 1983-05-23 1987-12-15 Fmc Corporation Heat recovery in the manufacture of phosphorus acids
DE3926105A1 (en) * 1989-08-08 1991-02-14 Metallgesellschaft Ag DEVICE FOR CATALYTICALLY CONVERTING AN H (ARROW DOWN) 2 (ARROW DOWN) S AND SO (ARROW DOWN) 2 (ARROW DOWN) CONTAINING GAS MIXTURE
MX2011004915A (en) * 2008-11-12 2011-05-30 Willem J Schipper Process for the manufacture of p4o6 with high yield.
KR20130041183A (en) * 2010-07-08 2013-04-24 솔베이(소시에떼아노님) Manufacture of lipo2f2 and crystalline lipo2f2
EP2605646B1 (en) 2010-08-18 2016-07-20 Monsanto Technology LLC Early applications of encapsulated acetamides for reduced injury in crops
CN113226535B (en) * 2018-11-19 2023-12-15 孟山都技术公司 Process for preparing phosphorus oxide and phosphoric acid

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SU179752A1 (en) * Научно исследовательский институт удобрени , инсектофунгици Method of producing phosphorus anhydride
GB197863A (en) * 1922-07-06 1923-05-24 Richard Threlfall Improved manufacture of phosphorus pentoxide
US2132360A (en) * 1936-05-19 1938-10-04 American Agricultural Chem Co Vaporizing and oxidizing phosphorus
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EP0242678A3 (en) * 1986-04-25 1989-02-01 Hoechst Aktiengesellschaft Process for the preparation of phosphorus pentoxide with reduced reactivity

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IT1106883B (en) 1985-11-18
JPS5510527B2 (en) 1980-03-17
IT7850721A0 (en) 1978-08-11
JPS5443195A (en) 1979-04-05
DE2860894D1 (en) 1981-11-05
AT377957B (en) 1985-05-28
ATA590878A (en) 1984-10-15
US4219533A (en) 1980-08-26
DE2736765A1 (en) 1979-03-01
EP0000698B1 (en) 1981-08-05
CA1097034A (en) 1981-03-10

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