CS230266B1 - Method of and apparatus for continuously preparing melt of condensed ammonium phosphates - Google Patents

Abstract

A process of continuous preparation of a melt of condensed ammonium phosphates by the reaction of phosphoric acid or a solution of ammonium phosphates in phosphoric acid with gaseous ammonia which is dosed into the reaction medium in excess and comprising neutralizing-dehydrating reaction between liquid phase and gaseous ammonia, takes place by continuous contact of phases in a film layer which is formed in the reaction medium by gradual pouring of the liquid phase under gravity and also by its dispersion with gaseous phase formed by a mixture of gradually warmed-up gaseous ammonia and gradually warmed-up steam. The apparatus comprises a standup through-flow film reactor (1) having one supporting bottom (2) with organized and/or non-organized filling (3), a supply of liquid phase containing phosphoric acid (4) and a supply of gaseous ammonia (5). The film reactor can also contain distribution partitions (6), directing the flow of reaction mixture in the filling, building-in (7) and/or static mixer (8). <IMAGE>

Description

The present invention relates to a process for the continuous preparation of a melt of condensed ammonium phosphates and to apparatus for carrying out the process.

Melt of condensed ammonium phosphates, containing a mixture of ammonium dihydrogen phosphate and condensed ammonium phosphates, characterized by the following chemical formula:

(NH 2) m H ( _{n +} 2) -ηιΡηθ ^ ι + Ιι where n> 2 amgn + 2, is the basic starting material - an intermediate in the production of clear or suspension liquid fertilizer suspensions. Several methods for its preparation are now known. The most elaborate and can be said that today the most widespread are the methods based on atmospheric or pressure neutralization of phosphoric acids of different concentration and purity with ammonia.

Various types of reactors, mainly of the tubular type, are used for the production of melt of condensed ammonium phosphates. T-reactors. The design of these reactors is protected by a variety of patents and copyright certificates, e.g., U.S. Pat. no. 2,985,513;

382 059; 3,420,624; 3,464,808; 3,723,086;

502 441; 3,503,706; 3,649,175; 3,650,727;

788 817; 3,733,191; 3,949,058; 3,734,708;

775 534; 3,939,255; 3,947,261; 3,950,495;

988 140; 4,250,147; French Pat. No. 1,493,803; South African Patent No. 67/5,808; DOS č. 1,909,438; 2,114,055; 2,308,716; Swedish Pat. no. 366 · 012 and Czechoslovak. AO č. 180 802.

Miscellaneous modified tubular reactors in connection with the production of condensed ammonium phosphates; · Swift. reactor, also published literature. The following may be cited: Chem. Eng. 21 (8), 60 (1972); Agric. Chem. 28, (2), 12 (1973); Fer.t. Solns. 17, (2) 44 (1973); ISMA Praha 1974 - Meline Ř. S .: "Production of High Polyphosphate Liquid Fertilizer by Pipe · Reactor Process"; Chim. · Prom. No. 10, 752-755 (1975); Phosp. and Potass. 90, 25 (1977) and Chem. Avg. 28, 53, (5), 229 (1978).

Although the use of tubular reactors has made substantial progress in the development of a device for producing a melt of condensed ammonium phosphates, they have some disadvantages. They require the processing of preheated and to a different degree concentrated phosphoric acid, which necessitates increased demands on technological energy consumption. The assembly of technological equipment tends to be

230268 quite complicated and therefore relatively labor intensive; the rupture of the technological units increases the possibility of an accident, worsens the overall energy balance of the process and the equipment is also demanding on the built-up space. Most of the tubular reactors used require pressurized metering of phosphoric acid, thereby increasing the corrosion resistance of the equipment used to dispense hot process acid. The processes usually do not allow the processing of extractive phosphoric acids containing a higher proportion of contaminants (especially Mg, Al, Fe, F and also organic substances), foaming of the reaction mixture and formation of incrusts on the reactor walls, negatively affecting the hydrodynamics of the process. They do not allow rational use. The heat released in the neutralization reaction, the design of tubular reactors in most cases, assumes the use of metallic construction materials. which, due to the extremely high corrosion aggressiveness of the reaction mixture, belong to the group of expensive and often limited materials available (silver, tantalum, stainless steels with relatively high Mo and Cr content). The use of tubular reactors assumes great accuracy and at least the proportionality of the dosing of the two basic reactants, usually imposes increased demands on the operation and observance of the operational discipline and therefore is not always the case. guaranteeing the achievement of the necessary level of operational certainty of the production equipment as a whole.

Most of the reported deficiencies have been solved by the use of continuous working. dispersing · neutralization-dehydration reactors, the basis of which; is bubbling the liquid reaction mixture. gas phase (čsl. AO číslo / 210 335, 205. 849} ^.; ...

/ .. Certain shortcomings in the use of bubbling. column type reactors. is the fact that. that. the apparatus operates with a liquid phase retention, preferably in a system where the liquid phase. The reaction mixture consists of a melt, which requires adherence to the stated procedure for the reaction. .powering equipment to. mainly during its decommissioning.

All the above mentioned disadvantages are in. substantially eliminated by the method of continuously preparing the melt of condensed ammonium phosphates by acid reaction. phosphorous containing 50 to 80% P2O5 at a temperature of 15 to 300 ° C, or by reacting a solution of ammonium phosphates in phosphoric acid with gaseous ammonia, which is added to the reaction medium in excess of the amount of ammonia bound in the melt in the form of ammonium phosphates in that the neutralization / dehydration reaction intercalates. the phosphorus - containing phase and the ammonia gas are in the form of a continuous phase contact in the. film layer. The film layer is in the reaction medium. it is formed by the gradual flow of the liquid phase under the influence of gravitational force and also by its dispersion of the gaseous phase, consisting of a mixture of successively superheated ammonia gas and successively superheated water vapor, over the surface of the reaction medium with surface contact of 7.10 ° to 1.8. lO ³ m2. m ³ , preferably 4.5.101. to 9.8. . 102. m2. m-third

The flow velocity of the gas phase flow ω is 1,102 to 1, preferably 2,10 ^-1 to 2,10 ° m. s ^-1 , wherein the gaseous mixture flows concurrently with the liquid phase flow.

The extra-layer fluid flow rate ω is characterized as the ratio of the volume flow rate of the fluid (eg, the vapor phase of the reaction mixture) to the cross-sectional area of the empty device (no charge).

The melt of condensed ammonium phosphates can be prepared on an apparatus according to the invention in which: consists in that it consists of a film reactor with at least one carrier bottom on which an organized and / or unorganized charge is deposited, wherein for a ratio of equivalent particle diameter of the charge de, defined as a diameter of a sphere equal to the volume of the particle the charge, and the inside diameter of the film reactor body, or the length of its longest side D, are:. ”10“ ³ á de / D gg 4,5.10 ~ l, for specific filling volume, so-called. the voidness ε holds that. 28 g ε gg 96 per cent,. preferably 60 <ε <. For a ratio of the total charge height H to the internal diameter of the reactor body, or the length of its longest side D, 1.1 gg H / D g 14.8, further comprising a liquid phase supply, is 80%. . containing. acid. phosphorus, which. mouth above. filling layer, gas supply. ammonia and, where applicable, distribution counters,. regulating the flow of the reaction mixture in the charge,. vostavbu. and / or a static mixer.

Specific volume volume,. called. gapiness. ε is a layer characteristic, being. defined as. ratio. volume of free space in. layer. k. volume of the entire layer

where Lo = height compact layer, i. the height of the particulate layer without gaps and L = the height of the layer.

The specific void volume of the layer greatly affects the value of the pressure losses. For particles of regular shapes, the specific void volume depends mainly on their shape and size, respectively. from the ratio of the particle diameter to the diameter of the device in which the layer is deposited. The spacing of the regular-shaped particle layers also depends on how the layer is formed.

An advantage of the process and apparatus of the present invention is that it makes it possible to rationally utilize the heat released in the reaction of the hot liquid phase containing phosphoric acid with ammonia gas; creates optimal conditions for heterogeneous reactions in the liquid and gas phase system; it imposes at least energy consumption requirements when dispensing a phosphoric acid-containing liquid reactant. The device furthermore enables a compact design of the reactor node with a smaller number of individual technological parts (dehydrate, reaction mixture separator and the like) and with minimized space requirements for the location of the technological part of the plant; the device is simple and does not contain any rotating parts; the device works with a high level of operational reliability and its function requires minimal demands on the operator.

One of many modifications of the device according to the invention is shown schematically in the attached figure.

Treated phosphoric acid, or a solution of NH4H2PO4 in phosphoric acid, continuously flows into the vertically positioned reactor through the liquid phase inlet 4 located in the upper part of the reactor body 1. The acid-reactive phosphorus-containing liquid reactant flows down the organized and / or unorganized cartridge 3 located on at least one carrier day 2. For a ratio of equivalent particle diameter of the cartridge d _e , defined as a diameter of a sphere equal to the volume of the cartridge particle The particle diameter is the same as the particle diameter) and the internal diameter of the reactor body D is that d _e / D is 0.005 to 0.45.

Any suitable natural materials may be used as the unorganized filler. Suitable, artificially manufactured cartridges are made in a variety of shapes such as Raschig, Lessing, Pall Rings, Crutch Seats, Cannon Cartridge and the like, and are also available in a variety of sizes. In terms of liquid phase separation, it has proven advantageous if the upper portion of the cartridge 3 is made up of particles for which the value of the de / D ratio discussed above is less than or equal to ^1.10-1 . It is also advantageous if the top layer of the cartridge is closed by a conical lamination of the cartridge particles, the inlet of the liquid phase opening just above the top of the cone.

The ammonia gas is fed to the neutralization-dehydration reactor via an inlet 5, which also opens either above the top layer of the cartridge 3 or extends to the top half of the cartridge layer 3. The phosphorus-containing liquid phase flows over the surface of the cartridge by shaking gravity. The presence of ammonia gas in the system results in an exothermic neutralization reaction between the dosing components. The formation of the film layer and the vigorous equalization of the concentration differences at the interfacial interface also significantly contribute to the entrainment of the liquid phase by the gas phase, which consists of gaseous ammonia and the reaction mixture released by superheated steam.

Because the contact of the reacting phases occurs in the film layer, favorable conditions are created for both the neutralization and the dehydration reaction.

It has also been found appropriate to incorporate into the interior of the reactor body 1 distribution baffles 6 which direct the flow of the reaction mixture over the surface of the charge, thereby achieving uniform wetting of the charge and further intensifying contact of the reacting phases. In certain circumstances, it is also possible to deepen the course of the neutralization-dehydration reaction by optionally incorporating a suitable installation 7 and / or a static mixer 8 into the interior of the reactor body 1.

The liquid phase of the reaction mixture which gradually changes its character by flowing over the surface of the reaction heat-heated charge 3 as a result of a continuously deepening neutralization and dehydration reaction and, in the case of processing, in particular phosphorous raw materials containing organic substances, also foams. This results in the formation of a certain "closure" which prevents the free passage of ammonia gas through the device and the movement of the reaction mixture through the device takes the form of a piston flow.

By passing the reaction mixture, both liquid and gaseous, through the last perforated carrier bottom 2, the foamed melt of condensed ammonium phosphates flows out of the reactor and can be further processed by direct dissolution, reaction with some of the constituents which are the source of the primary, secondary or trace plant nutrients, by granulation, or by flax treatment into its dosage form. The unreacted ammonia gas contained in the gas phase of the reaction mixture is particularly advantageous to use in some of the other stages of the process (e.g., to bind it in a weakly acidic aqueous melt solution while adjusting the acidity of the final product, etc.).

Example 1

We have examined the process for the production of condensed ammonium ions of the present invention on models of a neutralization-dehydration reactor apparatus constructed in accordance with the second point of its object, and this has been incorporated into a continuously operating apparatus assembly.

The neutralization-dehydration reactor consisted of a metal reactor housing of vertical cylinder shape, a total height of 1200 mm and an inner diameter of 155 mm. Approximately 20 mm from the bottom edge, a perforated support bottom comprising 37 circular openings, each 12 mm in diameter, was fitted into the reactor body. An unorganized filling consisting of earthenware Raschig rings of 230266 bones of 25.4 X 25.4 mm with a wall thickness of 3.6 mm was deposited on the carrier bottom to a height of 900 mm, which corresponded to 16.97.10 ~ ³ m ^{3 of} filling forming 3.225 m ^{2 of} contact the surface of which the average void volume, the so-called. the void ε, was 71% and the ratio of the equivalent particle diameter of the charge d _e to the inside diameter of the reactor body D was: d ^e / D = 22.87 / 155 = 1.47.1ο ^-1 .

An additional 100 mm layer of unorganized cartridge, consisting of ceramic Raschig rings, characterized by dimensions of 12.7 x 12.7 mm and a wall thickness of 1.8 millimeters, was placed on an already specified cartridge. The filling layer thus formed, whose average void volume, so-called &quot; the gap was about 70%, corresponding to 0.692 m ^{2 of} contact surface. The ratio of the equivalent diameter of the charge particles in this layer to the inside diameter of the reactor body was d _e / D = 11.44 / 155 = 7.38.10 ² . The last third layer of the cartridge, placed on the previous cartridge, was 75 mm thick and consisted of 6.35 X 6.35 mm ceramic Raschig rings, 0.76 mm thick.

The ratio of the equivalent diameter of the particle charge d _e, defined as the diameter of a sphere whose volume is equal to the volume of the particle charge and the internal diameter of the reactor body D was rov5 45 Ný d _e / D = ~ ² The last 3,52.10

155 the top layer of an unorganized cartridge, the average void volume, the so-called &quot; gap ε = 72 ° / o, a contact surface of 1.12 m ² was created. All fill layers used represented a total contact surface area of 5.037 m ² . The phosphoric acid and ammonia gas feed lines were part of a flange cover enclosing the reactor body from the top and exit approximately 50 mm above the last charge layer, whereby the acid supply was placed in the vertical axis of the reactor body.

The reactor body was insulated over the entire height with an approximately 80 mm thick basalt wool layer. A thermometer well filled with silicone oil with a thermometer was built in the lower third of the height of the reactor body.

We worked with partially concentrated commercial extraction acid, so-called. of a black type, specified before its concentration by the following chemical composition:

- total P2O5 content 54,91% (determined photometrically) - P2O5 content determined 56,27% by acidity conversion - iron content 0,49% Fe - aluminum content 0,387% AI - magnesium content 0,132% Mg - calcium content 0,064% Ca - content fluorine 0.456% F.

The acid of said quality, after concentrating to% P2O5 (as determined by photometry) on a continuously operating film evaporator, flowed through the liquid cap and a centrally located liquid phase feed at 1250 g / min. ¹ into an already specified reactor. The average temperature of the acid fed to the neutralization-dehydration reactor was 135.5 ° C.

On average, 286.1 g of ammonia gas were metered into the equipment under test by ammonia supply. The temperature in the lower third of the reactor height stabilized at 276 ° C after about 30 minutes of operation.

Under these conditions, we obtained, on average, 1274 g of a strongly foamed melt, specified by such an average content of basic ingredients: 11.7 - 62.8 - 0 (% N -% P2O5 -% K2O), with an average of 13.9% P2O5 bound in the form of orthophosphates and 48,9% of P2O5 in the form of condensed ammonium phosphates (average conversion - conversion to condensed phosphates α = 77,9%).

The prepared melt of condensed ammonium phosphates was directly processed into a liquid NP-fertilizer of the type 10-34-0 in the next step without any interruption, while we bound on average an average of 104.9 g of NH3 from the gaseous reaction phase into a weakly acidic melt solution.

The liquid NP-fertilizer obtained in this manner was a weakly acidic reaction (pH = 6.0) and had an average density of 1390 kg. m ^-3 . In terms of phase stability, the final product showed no changes even at long-term storage at -15 ° C.

Examples 2 to 17

The neutralization-dehydration reactor used during this series of experiments was involved in the assembly of a model continuously operating apparatus for the preparation of polyphosphate type nitrogen-phosphorus liquid fertilizers and consisted of:

A cylindrical reactor body made of impregnated graphite of 1000 mm height, 155X17.5 mm diameter, 37 holes of 12 mm diameter having been drilled in its bottom of 20 mm, thereby forming a perforated support base for receiving the filler;

- an unorganized filling consisting essentially of reinforced rings of graphite tubes 38/24 and 30/10 mm;

- phosphoric acid and ammonia gas inlets above the filler layer.

For the particles of the unorganized filler used, their characteristics were obtained by measurement and conversion, which are summarized in Table 1. First

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The first experiments with this type of graphodure packed-bed reactor were made with extraction H3PO4 which was continuously fed through a film evaporator into the reactor. On average, 6.65 was dosed during the first experiment. . 10 ~ 3 kg of unconcentrated H3PO4. ' with ¹ (23.94 kg. tq H 3 PO 4 .h ¹ ), while in further experiments. the average acid feed rate gradually increased by 64.4; 124.7 and 160.9 ·%, so in the last trial of this series, the average dose was already taken. 17.35 .. 10 ~ 3 kg H3PO4.S-1. In proportion to the gradual decrease of the concentration of trihydrogenphosphoric acid flowing from the evaporator into the reactor (due to the increased feeding of acid into the evaporator) in the individual experiments, the degree of conversion of monophosphates in the liquid phase of the reaction mixture to condensed phosphates. The highest average value of the degree of conversion in the melt samples taken during the experiment was 71.2%. The lowest proportion of condensed phosphates (61.4%) was determined in the melt samples of experiment 165, when the highest mass tested was used. at an acid dosing rate (17.35, 10; i kg. s -1) within the evaluated series of experiments. A continuous free flow of acid to the reactor was maintained during all experiments.

The reaction mixture flowed through the reactor uniformly, no unevenness in the reaction mixture or deficiencies in the function of the reactor to be tested were observed. The function of the reactor during the last two experiments was particularly favorably evaluated. series (164 'and 165), where the flow of the reaction mixture through the reactor' has reached a clear piston character. During the experiments. A to D was used with an extract acid of the same design and quality, except that the acid. - was pre-concentrated and in individual / experiments of the series discussed, it was only heated to 110-115 ° C by flowing through the evaporator without further evaporation: (the evaporator walls were tempered to a temperature below the boiling point of the acid 140-155 ° C). C). In this way, we managed to do more. rate of change of H3PO4 concentration in experimental determination of reactor capacity. .

In the individual experiments of this series, the following average dosing rates of H3BO4 were used (11.84; 16.22; 19.52 and 22.56). 10 ³ kg · H3PO4. with “1,” which replied · (7.39; 10.12; 12.18 · and 14.08). . ΙΟ. ³ kilograms P2O5. s_1. .

Recalculation based on the specified volumetric values. reaction mass. The mixture at the outlet of the reactor (305 to 563 kg .. m 3) was determined to have a mean residence time. of the reaction mixture decreased proportionally with increasing. . by dosing H3PO4 and NH3 (g) z. .245. up to 273 to 81 to 90 seconds. The degree of conversion of inonophos-7 formates to condensed phosphate ranged from 61.1 to 67.5%.

In two further experiments (167 A, B), the function of the reactor with the co-current flow of the reactants was tested in the case of the use of thermal trihydrogenphosphoric acid. The results of the experiments confirmed the possibility of using a packed-bed reactor of the described construction also for the preparation of KFA melt from the thermal H3PO4. However, it has been shown that achieving the optimum performance of a packed-bed reactor for thermal acid treatment would require maintaining a relatively narrow range of mass feed rates of H3PO4 and ammonia for the packed-bed reactor. In the processing of thermal trihydrogenphosphoric acid, the reaction mixture does not form a foam, as with the use of extraction H3PO4, where it fills the entire void space in the filler layer and is the cause of the spatial flow of the reaction mixture. In the case of thermic H3PO4 dosing, it flows down the surface of the filler in the form of a film layer, whereby its reaction with ammonia gas occurs by contacting the reacting phases at the phase interface.

Therefore, in the case of the thermal acid, it is important to work with optimal liquid-phase wetting of the filler, to use a finer filler with a larger surface and to prevent the formation of so-called &quot; the chimney flow of ammonia gas in the filler layer. The different character of the reaction mixture during the thermal acid tests was likely to negatively affect the size of the interfacial surface, resulting in a reduction in the degree of conversion of monophosphates to condensed phosphates by an absolute 10 to 20 · ·% compared to melt samples prepared under comparable extraction conditions. acid. It can be assumed that even in the case of a packed reactor of the tested type, the addition of additives reducing the surface tension of the reaction mixture and promoting its foaming (e.g., one of the lignosulfonic acid derivatives, etc.) would favorably influence the degree of molecular dehydration. . · Phosphoric trihydrogen acid.

During experiments 168 / A, B, the procedure was carried out with the already specified extraction H3PO4 so-called. black type. These experiments have been swept to experimentally investigate the possibility of using a · · · · · · · · · · vertical flow reactor · reaction mixture for high temperature neutralization of commercial trihydrogenphosphoric acids containing 52-54% • P2O5, · without prior concentration with ammonia gas. The achieved results of the experiments confirmed the fundamental suitability of the packed reactor of the supported structure for the studied process.

Moderate test results such as. An overview of some of the measured and calculated parameters for the tests with graphodure neutralization-dehydration-packed reactors is given in. Tables 2 and 3.

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Total reactor body volume, V _R (m ³ ): 10,91.10 '

Filling capacity, V _in (m ³ ): 10,12.10 '

Mean void volume in the filler layer: 67.9

During this series of experiments on a model continuously operating device, a packed neutralization-dehydration reactor made of impregnated graphite according to the invention is used, characterized as follows:

Specification of individual filler layers:

- total reactor body height 1000 mm - reactor body inner diameter 120 mm - number and size of circular holes in perforated bottom:

holes, 0 12 mm

Fill layer Bottom - graphite rings 38,4X6,95 / 29,9 mm Middle layer - graphite rings 30.0 X 10.0 / 88 mm Top layer - ceramic Raschig rings 14,9X2,7 / 14,8 mm Together 1. Volume of filler layer, V ΙΟ “ ³ (m ³ ) 9.78 0.17 0.17 10.12 2. Number of filler particles in layer (pcs) 160 20 71 251 3. Surface of all particles in layer A _s (m ² ) · 1.65 0,047 0,096 1,308 4. Specific surface a. 10 ¹ (m ² .m ^-3 ) 1.19 2.76 5.65 - 5. Gap,% 68.1 55.9 70.7 -

In the individual experiments of this series we processed extraction H ₃ PO _{4 of the} black type commercial grade, containing:

53.62% by weight, total P2O5 (determined by spectrophotometric analysis)

54.39% by weight of P2O5 as determined by acidity conversion

0.23% Fe by weight

0.16% Al

0.16% Mg and a

0.19% by weight of F, or a mixture thereof with industrial sulfuric acid. In the preparation of condensed ammonium phosphates by high temperature neutralization of mixed acids (H3PO4 4-H2SO4) with ammonia gas, the weight ratio P2O5 / S in the acid treated varied from 2,498 to 11,005 during each experiment. The temperature of the mixed acid at the reactor inlet varied from 75 to 110 ° C. An overview of the basic technological parameters is contained in Table 4.

230286 cd H

Experiment number Average dosage [g. min “ ¹ } Mass Temperature Degree of conversion Duration

H3PO4 H2SO4 [96.58%} NH3 ratio of P2O5 / S of mono-phosphorus-continuous reaction mixture · ¹ · ______ Г ___ _ »

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Hot melt condensed phosphonally processed by dissolution in ammonium ammonia obtained during the trial water to stabilize liquid fertilizer.

Owners of this experimental series were continual

Claims (2)

A process for the continuous preparation of a melt of condensed ammonium phosphates by reacting phosphoric acid containing 50 to 80% P2O5 at a temperature of 15 to 300 ° C, or by reacting a solution of ammonium phosphates in phosphoric acid with ammonia gas which is fed into the reaction medium in excess the amount of ammonia bound in the melt in the form of ammonium phosphates, characterized in that the neutralization-dehydration reaction between the phosphorus-containing liquid phase and the gaseous ammonia takes the form of continuous phase contact in the film layer which is formed in the reaction medium also its gas phase scattering, consisting of a mixture of successively superheated ammonia gas and successively superheated water vapor, over the surface of the reaction medium, with a contact surface of 7.10 ° to 1.8.10 ³ m ² . . m ³ , preferably 4.5.10 ¹ to 9.8.10 ² m ² . m ³ and the extra-layer velocity of the gas phase flow ω is 1.10 ~ ² to 1.10 ¹ , preferably 2. VYNALEZU. 10 ~ ^ι and second 10 ° m. s ^-L , wherein the gaseous mixture flows concurrently with the liquid phase flow. 2. Apparatus for the continuous preparation of a melt of condensed ammonium phosphates according to claim 1, comprising a fixed flow-through film reactor, characterized in that the film-reactor body (1) comprises at least one support bottom (2) on which it is arranged and / or unorganized charge (3), where, over the ratio of the equivalent particle diameter of the charge, to the inside diameter of the film reactor body, or the length of its longest side D, 5 .ΙΟ · ³ d _e / D 4,5.10 ¹ , 28 ε 96 percent, preferably 60 <<ε <80 percent, and for the ratio of the total charge height H to the inside diameter of the reactor body, or the length of its longest side D, 1.1 H / D 14.8, further comprising an inlet (4) of a phosphoric acid-containing liquid phase which extends above the layer of filler (3), an inlet (5) of ammonia gas and a distribution baffle (6), built-in (7) and / or static mixer (8).