SU1542610A1 - Reaction vessel - Google Patents

Abstract

The invention relates to reactors for producing phosphoric acid by increasing the efficiency of the operation by improving the conditions of decomposition and crystal formation. The reactor includes a housing divided into sections by partitions, in each of which there are agitators and a vacuum evaporator installed in the upper part of the housing. In the submerged-type vacuum evaporator, a vertical partition is installed, which divides it into sections, and inlet and outlet connections are mounted in each of these sections, immersed in one and in different sections of the housing. 1 il.

Description

The invention relates to equipment used to produce extraction phosphoric acid at the stage of phosphate decomposition and crystallization of calcium sulfate using a vacuum method for cooling the reaction slurry, and can also be used in other processes in which excessive heat of chemical reactions is released.

The purpose of the invention is to increase the working efficiency by improving the conditions of decomposition and crystal formation.

FIG. 1 shows a reactor cross section; in fig. 2 - the same, top view.

The reactor consists of a housing 1 with a lid 2, the internal volume of which is divided into sections (I, II, HI, 1Y) by partitions 3. In the sections there are agitators 4. A vacuum evaporator 5 of submerged type is installed in the upper part of the case. A vertical partition 6 is mounted in the vacuum evaporator, which divides it into sections a and b. And in each of the sections a and b posted inlet and outlet nozzles

for the pulp, respectively for section a7 and 8, for section b - 9 and 10. These nozzles are immersed under the level of the pulp in the reactor sections: inlet nozzles 7 and 9 are in one section III, and the output nozzles

8 and 10 - in different sections I and IY.

In one of the partitions 3, the circulator 11 of the pulp is placed in a special mine with the inlet and outlet windows for the pulp. In the lid 2 in sections I and III there are nozzles for injecting reagents 12 and 13 and for discharging reaction products 14 in sections III and IV. Section IV contains a device 15 for outputting the production pulp to filtration.

The reactor operates as follows.

Source reagents: phosphate, sulfuric acid and dilution solution enter housing 1, in sections I and II, limited by partitions 3 and cover 2, through nozzles 12 and 13. Mixers 4 mix the reagents in sections. At that, the reaction of phosphate decomposition with a mixture of sulfuric and phosphoric acids, as well as crystallisation

4 K

05

calcium sulfate solution. This releases excess heat of reaction.

In order to intensify the processes of decomposition and crystal formation, intensive recycling of the reaction pulp in the decomposition zone of the reactor (sections I, II, III) is carried out with the help of a circulator 11 through a vacuum evaporator 5. The reaction pulp from section I flows over into the partition 3 section II and then with the circulator 11 is injected into section III.

Section III creates a small difference in the level of the pulp compared to section I, which allows the pulp through pipes 7 and 8 and the section of the vacuum evaporator to flow through the vacuum evaporator like a siphon, vipip in it, and thus steam and heat, t . e. remove excess heat of reaction.

The vacuum evaporator 5 through the gas path is connected to a vacuum system for the absorption of fluorine gas and vapor condensation, which creates a given amount of discharge in it, regulating the heat removal. The production part of the pulp flows from section III to section IY through nozzles 9 and 10 and section b in a vacuum evaporator limited by partition 6. At the same time, the pulp cools down in section IY of the reactor, in which its maturation occurs, i.e. re-growth of calcium sulphate crystals and removal of residual supersaturation of the solution in CaO. The latter circumstance becomes possible due to the cooling down of the production part of the pulp in section b of the vacuum evaporator. This leads to a decrease in the degree of growth of filtration equipment and an increase in its service life due to a decrease in the corrosive properties of the pulp due to a decrease in its temperature.

The fluorine gas released into the gas volume of the reactor is discharged from under the cover 2 through the nozzle 14 into the sanitary absorption system. The production part of the pulp is brought out by the device 15 for filtration.

It should be noted that the reaction pulp flows recycled in the decomposition zone and section a of the vacuum evaporator, as well as from section III to section IV and in section b of the vacuum evaporator, differ sharply in size. Their ratio, respectively, is approximately equal to (40-10): 1. This circumstance allows uneven heat removal from these pulp flows: the temperature gradient of the pulp passing in section a,

ranges from 0.1 to 3 ° C, and in section b from 5 to 30 ° C.

The cross sections of the sections in the vacuum evaporator are taken in proportion to the heat removal from the pulp of the decomposition and maturation zones of the reactor according to

Ј- &,

F, Q2

Q where F and Qi are the cross-sectional area of section a and the amount of heat removed in the decomposition zone of the reactor;

FI and Q2, respectively, for section B of the reactor mature zone. 5 For the processes for producing an EPC, the FI.sub.F ratio is typically (5-15): 1. For the decomposition zone, it is important that there are no local temperature and concentration zones in the pulp, favorably affecting the degree of extraction from phosphate and obtaining homogeneous calcium sulfate crystals.

For the ripening zone, it is important to provide a predetermined degree of pulp cooling to remove the residual supersaturated CaO solution. Both of these conditions are met by the proposed reactor design, which makes it possible to increase its efficiency by improving the condition of decomposition and crystal formation. This is typical of modern two-temperature processes for the preparation of EPA, in which the pulp temperature is maintained at 90-100 ° C in the decomposition zone of the reactor, and 75-80 ° C in the ripening zone.

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Claims (1)

Invention Formula The reactor, comprising a vessel divided into sections by partitions, in each of which there are agitators, and a flooded type vacuum evaporator installed in the upper part of the case, with inlet and outlet pipes located below the level of the reaction slurry in adjacent sections, and a device for circulating reaction pulp, characterized in that, 5 in order to increase the efficiency by improving the conditions of decomposition and crystal formation, the vacuum evaporator is equipped with a vertical partition forming the chambers, in each of which the inlet and outlet nozzles are installed, the inlet nozzles are located in one section, and the output in different sections of the reactor vessel. 1542610 А-А To vacuum Pulp on fmypr 10 J5 Pulp on the filter V 10 Head A Telesntsky Editor and KasardaTehred and WereScorrector And Muska Order 361 Circulation 413 Subscription VNIIPI I State Committee on Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production and publishing combine “Patent, Uzhgorod, Gagarin str., 101 eleven L / eleven h 15 Fig.I 1i