SU1685501A1 - Reactor for producing phosphoric acid - Google Patents

Abstract

The invention relates to equipment for carrying out heat and mass transfer processes in the production of phosphoric acid and reduces power consumption while maintaining productivity. The reactor comprises a housing, closed by a lid, divided by vertical partitions and a transverse diaphragm into sections, equipped with a cooling unit and circulating screws. The cooling unit is located above the central section of the reactor, provided with intake ports that connect it to the sections enclosed above the transverse diaphragm, and is a hollow cylindrical body, the lower section of which is plugged below the pulp level, and in the upper part there is an annular air-distributing device with a coaxially located Discharge fitting The distribution device is made in the form of inclined radial plates, in terms of partially overlapping each other and forming a canal between them air passageways. 1 з.п f-ly, 3 ill. (Ls

Description

The invention relates to equipment for carrying out heat and mass transfer processes in the process of producing phosphoric acid.

The aim of the invention is to simplify the design of the reactor, reducing energy consumption and metal consumption while maintaining performance.

Structurally, the reactor can be made in two ways.

FIG. 1 shows a general view of the reactor; in fig. 2 - section A-A in FIG. one; in fig. 3 is a variant of section A-A in FIG. one.

The reactor is an apparatus with central 1 and peripheral 2 annular sections. Peripheral section on top closed by transverse flooded diaphragm

3, provided with ring guides 4 in which the cyclic screws 5 are installed. A pulp cooling assembly casing 6 is installed above the central section 1. Vertical partitions 7 are located between diaphragm circulators on the diaphragm, dividing the volume of the narphals, the diaphragm into separate sections, a row of which are connected by the intake ports 8 to the cooling unit. The cooling air is supplied to the cooling unit through the duct 9. In the second variant, the reactor is divided by two vertical partitions 10 to central 1 and two peripheral segment-section sections communicating in the bottom zone. Peripheral sections are closed on top of two flooded pol00 (L

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diaphragms 11, above which the working volume of the reactor is also divided into a number of sections by means of vertical partitions 7 installed between circulation screws.

The cooling unit is a hollow cylindrical body b, in the upper part of which an annular air distribution device 12 is installed with a coaxially located drain nipple 13. The lower part of the body is buried in the sublevel of the slurry, and the depth of the body and drain nipple should exceed the sum of the resistance values of the air distribution device and a layer of pulp over it in order to avoid air breakthrough down. The cooling air is supplied through the duct 9 under the air distribution device to the annular volume formed by the housing and the drain fitting.

The reactor operates as follows.

The pulp fills the reactor above the transverse diaphragm 3 in the first embodiment or above the semi-diaphragms 11 in the second embodiment. When the circulator 5 is turned on, intensive pulp circulation begins in it. At the same time, the pulp rises from the bottom zone of the reactor upward along the peripheral sections 2 to the guides of the 4 circulator-screws and enters the volume above the diaphragm. The pulp from the sections 7 enclosed with the help of vertical partitions through the intake openings 8 is fed into the housing 6 of the cooling cooling. The pulp pumped over by the remaining circulating screws is dropped directly into the central section 1 of the reactor, where it is mixed with the cooled pulp coming from the cooling unit through the drain fitting 13.

In the cooler, the slurry is poured onto the surface of the annular air distribution device 12 and under the action of the air flow into the casing 6, tangentially through the duct 9 and exiting at a speed of 2H-30 m / s through the slots between the inclined radial plates 14, is intensively rotated and saturated with air. The cooling effect is achieved due to a high degree of air dispersion, a decrease in the size of gas bubbles, and therefore an increase in the surface of the interfacial contact of liquid and gas fuzz. At the same time, the degree of dispersion of air in the pulp increases due to the turbulence of the aci1 1 pulp flow as it moves over the gas channels of the air distribution device. The rotational movement of the pulp contributes to the subsequent intensive separation of the gas phase from the liquid. The pulp released from the gas bubbles is discharged to the central section of the reactor via drain fitting 13, and the air saturated with water vapor and acid gases is withdrawn into the absorption system.

Two pulp circuits are created in the reactor — through the cooling unit and

Directly in the working volume of the reactor, they are intensively mixed in the central section.

Phosphate raw materials in the form of pulp and the dilution solution are fed to the central

section of the reactor. Sulfuric acid is supplied either to the central section, or to the cooler, or distributed at both these points. Filtration of the slurry is carried out through a flow elbow,

the inlet of which is recessed below the level of the pulp.

As is known, for the phosphoric acid production process, the temperature difference between the cooled and cooled pulp is

one of the determining parameters influencing the process of crystal formation. In order to produce larger and more homogeneous calcium sulphate crystals, the crystal formation process must be carried out in

the most mild conditions, which is determined by the minimum temperature difference of the pulp and its intensive mixing. In the proposed reactor with air cooling unit temperature difference

is minimal and its value can be easily adjusted with the help of an adjustable cooling air supply depending on the system load. Moreover, unlike the prototype, this regulation can be carried out in a wider range.

Claims (2)

Claim 1. A reactor for producing phosphoric acid, comprising a housing, a lid, vertical partitions fixed on a transverse diaphragm, dividing the inner space into sections, in each of which circulators are placed, and a cooling unit, characterized in that simplifying the reactor design, reducing energy consumption and metal content while maintaining performance, the cooling unit is designed as a hollow cylindrical body with vertical fins attached to it, separating over-diaphragmatic space into sections communicating by typesetting windows with a hollow cylinder, equipped with an air distribution device with a central drain fitting located coaxially in the upper part, while the lower part of the cylinder is located under the diaphragm in the central section. 2. The reactor according to claim 1, characterized by 1, that in the air distribution device is made in the form of inclined radial, partially overlapping plates, which form gaps between each other for the passage of gas. i Absorption gas Air I i t Faye. one / -BUT I FIG. 2 Aa eleven eleven YU Figz