BE378172A

BE378172A -

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Publication number: BE378172A
Authority: BE

Description

       

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    "PROCEDE   DE FABRICATION DE   SULFATE   NEUTRE   D'AMMONIAQUE   PAR OBTENTION DIRECTE DE CRISTAUX PAR VOIE SECHE, SANS FORMATION   D'EAUX-MERES   ET SUBSIDIAIREMENT SUPPRESSION DE L'ESSORAGE ET 
DE LA DESSICATION DES CRISTAUX" 
La partie correspondant au brevet français n    663.046   du 17 Février 1928, est la suivante : 
Dans la fabrication industrielle du sulfate d'ammo- niaque la fixation de l'ammoniaque sur l'acide sulfurique est obtenue par barbotage du gaz ammoniac dilué et hydraté dans un excès d'acide sulfurique dilue; ce qui conduit à obtenir un sel acide nageant dans les eaux-mères. L'essorage donne un sel resté acide et hydraté. sel qu'on fait ensuite sécher 

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 après neutralisation. 



   Ce procédé ordinairement usité peut donc être consi- déré comme une cristallisation du sulfate par voie humide, dans une solution acide. 



   Par opposition à ce système, la présente invention obtient par voie sèche, des   cristaux   neutres de sulfate d'am-   moniaque.   On n'utilise en effet, dans la présente invention, ni liquide hydraté acide, ni yn hydrata d'ammoniaque, ni du gaz ammoniacal hydraté, ni aucun liquide dissolvant pour pro- voquer par voie de saturation de la solution, la cristallisa- tion du sulfate d'ammoniaque. 



   La présente invention conduit directement à   l'obten-   tion d'un sulgate neutre sans cristallisation aqueuse ou humide et on supprime ainsi les opérations d'égouttage, esso- rage, neutralisation et séchage. 



   Le gaz ammoniac utilisé est du gaz anhydre, gazeux ou liquéfié tel, par exemple, qu'il est normalement produit dans les procédés de synthèse actuels. (Claude, Casale, etc..). 



   L'acide sulfurique utilisé est de l'oléum, mélange de mono-hydrateet d'une certaine quantité d'anhydride. On fait réagir directement le gaz ammoniac, l'oléum et la quan- tité d'eau   nécessaire     à   obtenir avec l'oléum de l'acide sul- furique mono-hydrate. On met les trois corps ci-dessus en contact   en.   pulvérisant les liquides dans une enceinte où on fait également arriver le gaz ammoniaque. 



   Dans l'enceinte, il a été,   s'il   y a lieu, préalable- ment fait un vide partiel, par exemple, en déplaçant l'air par le gaz ammoniac avant l'entrée en réaction de l'acide.. 



   On règle les arrivées d'eau, d'acide et de gaz ammo- niac de manière à maintenir un vide déterminé. Le gaz ammoniac est employé en excès par rapport à la saturation normale de l'acide de manière à obtenir un sulfate neutre sans eaux-mères, 

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 la réaction ayant lieu en milieu ammoniacal gazeux. 



   L'enceinte   où-   se produit la réaction est refroidie pour   éliminer   le dégagement calorifique produit par les réac-   tions,   On peut, du reste, pour ce refroidissement, utiliser les frigories produites par la détente de l'ammoniaque liquéfié lorsqu'on emploie le gaz sous cette forme; cette utilisation pouvant être faite soit directement dans xxxxxxxx l'enceinte   où   soit indirectement dans une chambre déterte spécoiale se produit la réaction/renfermant un faisceau tubulaire et dans lequel circule 1'solde avant la réaction. 



   Le sulfate produit par voie sèche, est collecté par gravité dans la partie inférieure de la chambre de réaction   d'au   il est évacué en continu, au moyen d'un robinet écluseur étanche, commandé. Le sulfate débouche dans une nochers étanohe munie d'un arbre portant des palettes, disposées en ailettes pour retourner le sel, le faire avancer vers un ro- binet extracteur et 1'évacuer à   l'atmosphère.   



   Cette nochère est placée sous vide réduit de manière à permettre l'élimination des dernières parties de gaz ammoniac non saturé qui a pu rester interposé entre les   cristaux..   



   Ce gaz ammoniac ainsi récupéré est renvoyé dans la chambre de réaction où il rentre en circuit ou est oondensé séparément. 



   La partie   oorrespondant à   la première addition fran- çaise n    35.702,   relative au brevet français n  663.046, est la suivante : 
Le brevet précité décrit un procédé d'obtentionde sulfate neutre d'ammoniaque anhydre, obtenu par voie de cris- tallisation sèche en faisant réagir   directement   le gaz ammoniaque en excès et anhydre sur un mélange d'oléum et d'eau. ' 
Le sulfate recueilli dans le procédé indiqué peut se présenter sous forme de cristaux très fins (sulfate neige). 



   La présente invention est relative à un procédé 

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 permettant d'éviter la production de sulfate en petits cris- taux. 



   On utilise le mode opératoire décrit   dansx   le brevet préoité et on fait réagir dans l'appareil décrit et au milieu d'une atmosphère d'ammoniaque anhydre en excès, de l'oléum à un degré de concentration en anhydride variant entre 20 et 70%. L'eau nécessaire   à   la transformation de l'oléum en mond-hydrate est introduite sous la forme de vapeur saturée ou surchauffée*   à   une température déterminée. 



   La chambre de réaction est soigneusement calorifugée. 



  La chaleur dégagée par la formation du mono-hydrate d'une part (oléum et vapeur   d'eau)   et du sulfate d'ammoniaque d'autre part (acide sulfurique mono-hydraté et ammoniaque sec) est suffisante pour que le sulfate d'ammoniaque produit soit im- médiatement fondu. On règle le degré de concentration de l'oléum et la température de la vapeur d'eau de manière que cette température se maintienne aux environs de 160 degrés. 



  On peut ainsi extraire de la chambre de réaction du sulfate d'ammoniaque liquide que l'on fait refroidir. Il se prend en masse et est ensuite concassé suivant les besoins. 



   La partie relative à la deuxième addition française n  35.577, relative au brevet français 663.046 est la suivante : 
Dans le brevet principal français n    663.046   est XX XXXXXXXXXX décrit un procédé d'obtention directe de sulfate neutre d'ammoniaque anhydre à partir de ga z ammoniac anhydre, d'oléum et d'eau. 



   La première addition n  35,702 relative au brevet précité constate le fait que le sulfate d'ammoniaque préparé par le procédé peut être aggloméré par fusion en utilisant pour cette fusion la ohaleur dégagée par la réaction. 



   La présente, invention a pour objet : 
1 ) les perfectionnements suivants : 

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Pour éviter de porter le sulfate neutre d'ammoniaque à la température élevée nécessaire à sa fusion et d'opérer sous une forte pression d'ammoniac, nécessaire à la stabilité du sel neutre à cette température, on traite d'abord l'acide sulfurique ou l'écléum, ou le mélange des deux par l'ammoniaque gazeux anhydre de façon à ne former que du sulfate acide d'am- moniaque qui fond à 1400 environ ou un mélange de sulfate acide et de sulfate neutre d'ammonium fondant soit à plus basse, soit à plus haute température. 



   La masse fondue est pulvérisée par un moyen quelcon- que dans une atmosphère de gaz ammoniac anhydre à une pression queloonque et la neutralisation du produit obtenue est coin- plétée par contact avec le gaz ammoniao anhydre à la pression atmosphérique ou sous toute autre   pression,   à une température déterminée avec ou sans agitation.

   Ces diverses phases de la fabrication peuvent être réalisées dans un seul ou plusieurs appareils, en continu ou en discontinu, 
2 ) Le produit obtenu par le procédé ci-dessus, qui se présente sous un aspect physique différent du produit habituel,   REVENDICATIONS   
1 - Procédé d'obtention par voie de cristallisation sèche sans formation   d'eaux-mères   du sulfate neutre d'ammoniaque cristallisé consistant à faire réagir directement du gaz am- moniao en excès et anhydre sur un mélange d'oléum et d'eau.



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    "PROCESS FOR THE MANUFACTURING OF NEUTRAL AMMONIA SULPHATE BY DIRECT OBTAINING CRYSTALS BY THE DRY METHOD, WITHOUT FORMATION OF MOTHER WATERS AND SUBSIDIARILY REMOVAL OF SPIN AND
DESSICATION OF CRYSTALS "
The part corresponding to French patent n.663.046 of February 17, 1928, is as follows:
In the industrial manufacture of ammonia sulphate, the fixation of ammonia on sulfuric acid is obtained by bubbling dilute and hydrated ammonia gas in an excess of dilute sulfuric acid; which leads to obtaining an acid salt swimming in the mother liquors. Spinning gives a salt that remains acidic and hydrated. salt which is then dried

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 after neutralization.



   This commonly used process can therefore be regarded as a wet crystallization of sulphate in an acid solution.



   In contrast to this system, the present invention obtains dry neutral ammonia sulfate crystals. In fact, neither acidic hydrated liquid, nor ammonia hydrate, nor hydrated ammoniacal gas, nor any dissolving liquid is used in the present invention to cause crystallization by saturation of the solution. ammonia sulfate.



   The present invention leads directly to the production of a neutral sulgate without aqueous or wet crystallization and the operations of draining, spinning, neutralization and drying are thus eliminated.



   The ammonia gas used is anhydrous, gaseous or liquefied gas such as, for example, that it is normally produced in current synthesis processes. (Claude, Casale, etc.).



   The sulfuric acid used is oleum, a mixture of monohydrate and a certain quantity of anhydride. The ammonia gas, the oleum and the quantity of water necessary to obtain the oleum are directly reacted with the sulfuric acid monohydrate. We put the three bodies above in contact in. spraying the liquids in a chamber where ammonia gas is also made to arrive.



   In the enclosure, if necessary, a partial vacuum has been previously created, for example, by displacing the air with ammonia gas before the acid reacts.



   The inflows of water, acid and ammonia gas are regulated so as to maintain a determined vacuum. Ammonia gas is used in excess with respect to the normal saturation of the acid so as to obtain a neutral sulphate without mother liquors,

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 the reaction taking place in a gaseous ammoniacal medium.



   The enclosure where- takes place the reaction is cooled to eliminate the heat release produced by the reactions. We can, moreover, for this cooling, use the frigories produced by the expansion of liquefied ammonia when using the gas in this form; this use can be made either directly in the enclosure where either indirectly in a special detection chamber occurs the reaction / enclosing a tube bundle and in which circulates 1'solde before the reaction.



   The sulphate produced by the dry process is collected by gravity in the lower part of the reaction chamber and is continuously discharged by means of a sealed, controlled lock valve. The sulphate emerges in an ethanol chamber fitted with a shaft carrying pallets, arranged in fins to return the salt, to make it advance towards an extractor valve and to evacuate it to the atmosphere.



   This nocher is placed under a reduced vacuum so as to allow the elimination of the last parts of unsaturated ammonia gas which may have remained interposed between the crystals.



   This ammonia gas thus recovered is returned to the reaction chamber where it enters the circuit or is oondensed separately.



   The part corresponding to the first French addition n.35,702, relating to French patent n. 663,046, is as follows:
The aforementioned patent describes a process for obtaining neutral sulfate of anhydrous ammonia, obtained by dry crystallization by directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water. '
The sulphate collected in the indicated process can be in the form of very fine crystals (snow sulphate).



   The present invention relates to a process

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 to avoid the production of sulphate in small crystals.



   Using the procedure described in the previous patent and reacting in the apparatus described and in the middle of an atmosphere of anhydrous ammonia in excess, oleum at a degree of anhydride concentration varying between 20 and 70%. . The water necessary for the transformation of oleum into mond-hydrate is introduced in the form of saturated or superheated steam * at a determined temperature.



   The reaction chamber is carefully insulated.



  The heat given off by the formation of the monohydrate on the one hand (oleum and water vapor) and of the ammonia sulphate on the other hand (sulfuric acid monohydrate and dry ammonia) is sufficient for the sulphate of ammonia produced is immediately melted. The degree of concentration of the oleum and the temperature of the water vapor are adjusted so that this temperature is maintained around 160 degrees.



  It is thus possible to extract liquid ammonia sulphate from the reaction chamber which is cooled. It sets in mass and is then crushed as needed.



   The part relating to the second French addition n.35,577, relating to the French patent 663,046 is as follows:
In the main French patent n 663,046 is XX XXXXXXXXXX describes a process for the direct obtaining of neutral anhydrous ammonia sulfate from anhydrous ammonia ga z, oleum and water.



   The first addition no. 35,702 relating to the aforementioned patent recognizes the fact that the ammonia sulphate prepared by the process can be agglomerated by melting using for this melting the ohaeat released by the reaction.



   The present invention relates to:
1) the following improvements:

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To avoid bringing the neutral ammonia sulphate to the high temperature necessary for its fusion and to operate under a high ammonia pressure, necessary for the stability of the neutral salt at this temperature, the sulfuric acid is first treated. or eclum, or the mixture of the two with anhydrous gaseous ammonia so as to form only acid sulfate of ammonia which melts at about 1400 or a mixture of acid sulfate and neutral ammonium sulfate melting either at a lower temperature or at a higher temperature.



   The melt is sprayed by any means into an atmosphere of anhydrous ammonia gas at any pressure, and the neutralization of the product obtained is completed by contact with the anhydrous ammonia gas at atmospheric pressure or any other pressure, at any pressure. a determined temperature with or without agitation.

   These various stages of manufacture can be carried out in one or more devices, continuously or discontinuously,
2) The product obtained by the above process, which has a physical appearance different from the usual product, CLAIMS
1 - A process for obtaining, by dry crystallization without the formation of mother liquors, crystallized neutral ammonia sulphate consisting in directly reacting excess ammonia gas and anhydrous with a mixture of oleum and water.

Claims

2 - A process for obtaining by dry crystallization without the formation of mother liquors of neutral ammonium sulphate crystallized according to claim 1, characterized in that the ammonia gas is used in excess and that the quantities of oleum and water are rigorously dosed to obtain a 100% acid monohydrate, so that the reaction gives a neutral and dry sulfate. without mother liquors. <Desc / Clms Page number 6>

3 - Process for obtaining by dry crystallization without formation of mother liquors crystallized neutral ammonium sulphate, according to the preceding claims, charac- terized in that the frigories originating from the expansion are used. liquid ammonia as produced by automatic synthesis processes, to limit the temperature of formation of ammonia sulfate.

4 - Process for obtaining, by dry crystallization without formation of mother liquors, neutral ammonium sulphate crystallized, according to the preceding claims, charac- terized in that the ammonia gas trapped between the molds crystallized salt is removed by cold evaporation under vacuum, to be absorbed separately or re-energized.

5 - Process for obtaining by dry crystallization without the formation of mother liquors crystallized neutral ammonium sulfate, according to the preceding claims, and means for carrying out the process, characterized in that ' the ammonia gas, the oleum and the quantity of water necessary to be obtained are reacted directly with the oleum of sulfuric acid monohydrate, the above bodies being brought into contact by spraying the liquids in a chamber where the ammonia gas is also made to arrive, preferably a partial vacuum is created beforehand in the chamber, in particular by displacing the air by the ammonia gas before the entry into the reaction of the acid.

6 - Process for obtaining by dry crystallization without formation of mother liquors of the crystallized neutral ammonium sulfate, according to the preceding claims, and means for carrying out the process, characterized in that for on cooling, the frigories produced by the expansion of the liquefied ammonia can be used when the gas is used in this form; this use can <Desc / Clms Page number 7> be made, either directly where the reaction takes place, or directly in a special expansion chamber containing a tube bundle in which the aid circulates before the reaction.

7 - Process for obtaining by dry crystallization without the formation of mother liquors crystallized neutral ammonia sulphate, according to the preceding claims, and means for carrying out the process, characterized in that the sulphate produced is collected by gravity in the lower part of the reaction chamber from where it is continuously evacuated, by means of a sealed, controlled sluice valve, the sulphate opening into a sealed chamber fitted with a shaft bearing pallets, arranged in fins to turn the @ salt. make it flow towards an extractor valve and evacuate it to the atmosphere;

this noohère is placed under reduced vacuum so as to allow the elimination of the last parts of unsaturated ammonia gas which may have remained interposed between the crystals; furthermore, the recovered ammonia gas is returned to the reaction chamber where it enters the circuit or it is condensed separately.

8 - Improvements to the process and to the means for obtaining, by dry crystallization, neutral crystallized ammonia sulphate obtained by directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water, characterized in this avoids the formation of sulphate in the form of very fine oristals (snow sulphate), by using the calories resulting from the transformation of the anhydrous into mono-hydrate and from the formation of sulphates which makes it possible to obtain The neutral sulfate of anhydrous ammonia is melted and upon cooling in the atmosphere the crystals agglomerated.

9 - Perforations, according to the preceding claims and more especially according to claim 8, <Desc / Clms Page number 8> to the process and to the means for obtaining by dry crystallization of neutral sulphate of crystallized ammonia obtained by directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water, characterized in that that the oleum which reacts in the middle of an atmosphere of anhydrous ammonia in excess, at a degree of anhydride concentration varying between 20 and 70% water, necessary for the transformation of oleum into monohydrate , is introduced in the form of saturated or superheated steam, at a determined temperature.

10 - Improvements according to the preceding claims and more especially according to claims 8 and 9, to the process and to the means for obtaining, by dry crystallization, neutral crystallized ammonium sulphate obtained by directly reacting gas excess ammonia and anhydrous on a mixture of oleum and water, characterized in that the reaction chamber is carefully insulated, the degree of conoentration of the oleum and the temperature of the water vapor are regulated so that this semi-maintained temperature around 160 degrees C.

11 - Improvements to the process and to the means of obtaining, by dry crystallization, neutral crystallized ammonium sulphate, obtained by directly reacting excess anhydrous ammonia gas with a mixture of oleum and water, characterized in that to avoid bringing the neutral ammonia sulfate to the high temperature necessary for its fusion and to operate under a high ammonia pressure, necessary for the stability of the neutral salt at this temperature, it is treated with 'first sulfuric acid which can have any concentration or oleum,

or mixing the deunts with anhydrous gaseous ammonia so as to form only acidic sulphate of ammonia which melts at about 140 or a mixture of acid sulphate and neutral sulphate of ammonium melting either at lower or at higher temperature. <Desc / Clms Page number 9>

12 - Perfectionnements.d'apr the preceding claims and more especially according to claim 11, to the process and means for obtaining by dry crystallization, neutral crystallized ammonium sulfate, obtained by directly reacting ammonia gas in excess and anhydrous over a mixture of oleum and water, characterized in that the melt is sprayed by any means into an atmosphere of anhydrous ammonia gas at any pressure and the neutralization of the product obtained is completed by contact with anhydrous ammonia gas at atmospheric pressure or under any other pressure, at a determined temperature with or without stirring. These various stages of manufacture can be carried out in one or more devices, continuously or discontinuously.

13 - Improvements to the process and to the means of obtaining, by dry crystallization, neutral crystallized ammonia sulphate, obtained by directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water, characterized in that the product obtained has a physical appearance different from the usual product.

SUMMARY - a) Process for obtaining, by dry crystallization without formation of mother liquors, crystallized neutral ammonia sulphate consisting in directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water . b) Improvements to the process and to the means for obtaining, by dry oristallization, neutral crystallized ammonium sulphate obtained by directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water, characterized in what to avoid the formation of sulphate under <Desc / Clms Page number 10> form of very fine crystals (sulphate snow), using the calories, resulting from the transformation of anhydrous into monohydric and from the formation of sulphate, which makes it possible to obtain in the molten state,

neutral sulphate of anhydrous ammonia and, on cooling in the atmosphere, agglomerated crystals. a) Improvements to the process and to the means for obtaining, by dry crystallization, neutral crystallized ammonium sulphate, obtained by directly reacting excess and anhydrous ammonia gas with a mixture of oleum and water, characterized in that to avoid bringing the neutral ammonia sulphate to the high temperature necessary for its fusion and to operate under a high ammonia pressure, necessary for the stability of the neutral salt at this temperature, one first processes sulfuric acid or oleum,

or the mixture of the two with anhydrous gaseous ammonia so as to form only acid sulphate of ammonia which melts at about 140 or a mixture of acid sulphate and neutral sulphate of ammonium melting either at lower or higher high temperature.