RU1787152C - Set-up for preparing granular mineral fertilizers - Google Patents

Abstract

The invention relates to the chemical industry, in particular to the production of mineral fertilizers. The purpose of the invention is to increase productivity and expand technological functions due to the possibility of obtaining ammophos and diammophos on one plant. The goal is achieved in that in a plant for the production of granular mineral fertilizers, including a device for the preparation of dilute phosphoric acid and cooling ammonia, two series-mounted reactors, a drum-granulator-dryer, a crushing, classification and cooling system, between the series-mounted reactors are capacitive apparatus and pulp collector with a steam separator. 1 ill.

Description

The invention relates to the field of chemical industry, in particular to the production of mineral fertilizers.

The purpose of the invention is to increase productivity and expand technological functions by providing ammophos and diammophos in one plant.

Examples of the method.

The drawing shows the proposed installation for the production of granular mineral fertilizers.

The installation includes a collection tank 1 of extraction phosphoric acid (concentration of 52-54% PaOs). a collection container 2 for diluting the acid with the spent absorption liquid from the tanks. Next, a ammonia self-cooler 5, a tubular reactor 6 with pipelines for supplying liquid ammonia 7 and phosphoric acid 8 and a slurry pipe 9, a capacitive apparatus 10, a pulp collector 11 with a mixer and a steam separator 12, a second tubular reactor 13 with a pulp feed pipe 14 from a collector 11 and supply of ammonia 15 from the self-cooler 16 and the slurry pipe 17 of the pulp supply of ammonium phosphates to the apparatus BGS 18 (drum pellet torus dryer).

The 6.13 tubular reactor consists of a mixing head and a reaction tube. In order to prevent ammonia from entering the apparatus 10 and the formation of an explosive mixture, a blocking system is installed that automatically cuts off the reagent supply for various types of malfunctions.

In order to avoid pulp getting into technological communications on pipelines of liquid ammonia 7, 15 and phosphoric

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acid 8 installed check valves 21,:.

In order to prevent ammonia from entering the BGS 18 apparatus and the formation of an explosive mixture, blocking systems were installed to cut off the ammonia supply for various types of malfunctions, as well as to cut off the pulp from the reactor 13.

The pulp is transferred from the collection vessel 11 to the tubular reactor 13 by a pump 22, the acid from the collection vessel 2 to the tubular reactor 6 by the pump 23.

Automatic control of the flow of oxygen and ammonia in the tubular reactor 6 and the flow of ammonia and pulp in the tubular reactor 13 and automatic control of the pressure in the apparatus 10 are provided.

The apparatus 18 is a rotatable drum with a speed of 4 rpm, mounted with an inclination angle of 3 °. The heat carrier is generated in the furnace 24.

The elevator 25, the screens 26, the apparatus of the FS gushing layer are connected in series with the apparatus 18. 27, finished product conveyor 28.

The apparatus also contains estruses 29 for returning the fine fraction to the BGS apparatus, a hammer mill 30 for grinding a large fraction of the product, and a process gas purification system.

The gas purification system includes an absorber 31, a spray trap 32, sewage collectors 33 and 34, and pipelines. Supplying gases and absorption liquid. ..

The operation of the installation is described in two versions: by the examples of the preparation of diammonium phosphate and ammophos.

The process for producing diammonium phosphate is carried out as follows.

Phosphoric acid with a concentration of 52- 54% RaOb enters the collection tanks 1, from where it is sent to the collection tanks 2, where it is mixed with the spent absorption liquid coming from the tanks. Diluted to a concentration of 38-48% PaOs (phosphoric acid) by pump 23 through line 8, they are sent to pipe reactor 6, where liquid ammonia also flows through line 7 from self-cooler 5.

 Formed from the pulp after the first tubular reactor with a molar ratio of МНз: НзР04 1.25-1.45 enters the TO tank, in which the pressure is automatically maintained no more than 2.3 kgf / cm2. Further, the pulp enters the pulp collector 11, where the separation is carried out. the excess steam. From the collector 11, the pump 22 passes through the pipeline 14 to the tubular reactor 13, where ammonia from the self-cooler 16 is simultaneously supplied.

the reactor 13, the pulp is adjusted to a molar ratio Г 1Нз: НзР04 1,6-1,7, and by gravity through the pulp line 17 it enters directly into the BSS apparatus through the nozzle.

The ammophos preparation process is carried out as follows.

Phosphoric acid with a concentration of 52-54% PaOs enters the collection camp.

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compilations 2 where mixing takes place

acid with spent absorption

fluid coming from tanks. ;

The acid diluted to a concentration of 405 to 45% PaOs is pumped into the tubular reactor 6 by pump 23, where ammonia is also sent. Formed from the pulp with a molar ratio of МНз. НзРОз 0.7-0.75 enters the capacitive apparatus 10 and then to the collection

0 pulp 11, From the collector 11, the pulp is sent to the second tubular reactor 13. In the reactor 13, the pulp is mixed with ammonia and neutralized to a molar ratio MH3: H3P4 of 1.05-1.25 °. Further by gravity she

5 enters the BGS apparatus. The further processing of the product is similar to that for the production of diammonium phosphate. .

The granular product is dried in the BGS 18 apparatus due to the self-evaporation of moisture from the pulp, heat of the flue gases, and heated particles of the reture.

The dried purge from the apparatus 18 is fed with an elevator 2.5 into the screens 26, where it is divided into three fractions.

5 A fine fraction of up to 1 mm from the screens 26 flows downstream of the streams 29 into the intake chamber of the apparatus 18 and the head of the apparatus for conveying the curtain is transported by the reverse screw. A large fraction (more than 4 mm) from a group of 0 hot water enters the hammer mill 30, then to the elevator 25 and then to sieving.

The commercial fraction (1-4 mm) from the screens 26 enters the apparatus of the gushing layer FS 27, where it is cleaned of dust and cooled. The cleaned and chilled product is conveyed via conveyor 2.8 to a finished product warehouse.

The dust-gas mixture after the apparatus BHS 18 is fed into the absorber 31 dl

0 purification from dust, ammonia and fluoride compounds. The absorber is irrigated through a nozzle with a solution of ammonium phosphates supplied by centrifugal pumps from the collection of absorption liquid. Exhaust gas from the absorber is discharged through the upper part of the absorber through a spray trap 32. The spent absorption liquid is pumped to the supply tank. Purified gases after the spray 32

fans are emitted into the atmosphere.

The connection of two tubular reactors through a capacitive apparatus by increasing the contact time of phosphoric acid with ammonia allows a deeper neutralization reaction and, as a result, a significant reduction in the ammonia content in the gas phase and the possibility of controlling the degree of ammonization before the 2nd stage of neutralization, which contributes to improve installation performance.

: The serial connection of two tubular reactors through a buffer tank with a steam separator allows the removal (excess) of moisture and thereby reduce the moisture content of the pulp supplied for drying from 25-30 to 15-20%, reduce the moisture saturation of the exhaust flue gases and to provide the moisture content in the product necessary for the drying process in the BHS apparatus.

Thus, the proposed installation for the production of mineral fertilizers allows you to get a new positive effect, which consists in the possibility of obtaining several types of mineral fertilizers in one installation (according to the non-flow chart) and increase its productivity due to:

greater completeness of the neutralization reaction of the extraction of phosphoric acid with ammonia;

reducing the intensity of the process by separating the stages of neutralization in space and time;

the possibility of smoothly adjusting the degree of emmonization before the second stage of neutralization;

separating excess moisture before the second stage of neutralization;

improving the processability.

At the proposed installation, it is possible to obtain mineral fertilizers with trace elements (copper, boron and others),

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A plant for the production of granular mineral fertilizers, including devices for the preparation of dilute phosphoric acid and cooling ammonia, two reactors in series, a drum pellet dryer, a crushing, classification and cooling system, characterized in that, in order to increase productivity and expand technological functions due to the possibility of obtaining ammophos and diammonium phosphate in one plant, a capacitive apparatus is located between successively installed reactors and a collection of the pulp from the steam trap.

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Compiled by R. Gerasimov

Editor T. Khorina Tehred M. Morgenthal Corrector N. Revska

Order 267 Circulation Subscription

VNIIIPI of the State Committee for Inventions and Discover at the USSR State Committee for Science and Technology 113035, Moscow, Zh-35, Rauska nab., 4/5

Production and Publishing Plant Patent, Uzhhorod, 101 Gagarin St.