SU858862A1 - Extraction process automatic control method - Google Patents

Description

(54) METHOD FOR AUTOMATIC CONTROL OF EXTRACTION PROCESS

one

The invention relates to automating the extraction process, and more specifically to automating the management of the process of extracting phosphoric acid and can be used in the metallurgical and chemical industries, in particular in the production of mineral fertilizers.

A known method of controlling the extraction process is by changing the solvent supply to the extractor depending on the temperature of the steam mixture in extractor 1.

There is a known method for automatically controlling the extraction process by varying the supply of phosphoric acid to the extractor depending on its consumption, the consumption of raw materials and the ratio of solid and liquid phases in the pulp, the supply of sulfuric acid to the extractor depending on its consumption, the consumption of raw materials and the concentration of excess sulfuric acid in pulp, changes in the magnitude of the vacuum in the vacuum evaporator, depending on the temperature and concentration of excess phosphoric acid in the extractor, changes in the discharge of the pulp, depending on its level in straktore 2.

The disadvantage of this method is that it does not provide a high quality of the output product due to the lack of precise control.

The purpose of the invention is to increase the productivity and quality of the output product by improving the control accuracy.

This goal is achieved by additionally measuring the flow rate and density of the circulating pulp, and by the sum of the indicated parameters and the flow rates of sulfuric and phosphoric acid, the vacuum value is adjusted, and the supply of phosphoric acid is adjusted by the consumption of sulfuric acid.

The drawing shows an automatic control system for the extraction process, a schematic diagram.

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The method is as follows.

Claims (2)

The concentration of excess sulfuric acid in the reaction zone of extractor 1 is measured by sensor 2 and controlled by regulator 3 by acting on valve 4 to supply sulfuric acid to the extractor. The regulator also receives an additional signal from the compensating device 5, designed to compensate for the effect of disturbance on the change in supply side of the fossil, whose consumption is measured by sensor 6. The temperature in the reaction zone of the extractor 1, measured by sensor 7, is maintained by the regulator 8, by changing the vacuum in the vacuum evaporator 9. The regulator 8 also receives an additional signal from the adder 10, the output of which receives the compensating signals from the compensating devices 11-13, which are proportional to ignals from disturbances due to changes in the amount of fosyr, flow and density of circulating pulp, measured respectively by sensors 6, 14 and 15, as well as from compensating devices 16 and 17, which ensure the condition of autonomy, due to which the temperature control process does not depend on sulfuric and circulating acid, which are measured by sensors 18 and 19, respectively. The ratio of the liquid and solid phases, measured by sensor 20, is adjusted by regulator 21 by changing the circulating acid supply by valve 22. Regulator p It also receives an additional signal from the adder 23, the input of which receives a signal from a compensating device 24, designed to compensate for disturbance from the change in consumption of fossyr, and a signal from a compensating device 25, designed to provide autonomy from the consumption of sulfuric acid, measured by sensor 18. pulp in the extractor, measured by sensor 26, is controlled by regulator 27 by changing the amount of pulp going to be filtered by valve 28. The control process takes place in the following way. If the phosphorus feed to the extractor is not changed, then, in the absence of a control system, this leads to changes in the concentration of excess sulfuric acid, the temperature in the reaction zone and the ratio of the liquid and solid phases. Since the process is inertial and all parameters are interconnected, conventional single-loop systems only react to this after changing these parameters, i.e., some time after changing the phosphorus product, and then with great error. When the feed of phosphorus to the extractor is changed, the compensating devices 5, 11 receive signals to the controllers 3, 8, and 21, respectively. Regulators 3.8 and 21, in turn, compensate for the change in phosphorus feed by changing, respectively, the consumption of sulfuric acid to the extractor, the vacuum in the vacuum evaporator, and the consumption of circulating phosphoric acid. In this way, the values of the concentration of excess sulfuric acid, the temperature and the ratio of the liquid and solid phases are independent of the feed of phosphorus. The independence of the temperature value from changes in the flow rate and density of the circulating pulp is achieved by devices 12 and 13. When the consumption of sulfuric acid in the extractor changes, the compensating devices 17 and 25 receive signals to the controllers B and 21. The controllers 8 and 21, in turn, change the vacuum in the vacuum evaporator and the consumption of phosphoric acid circulating; This ensures the autonomy of the temperature and the ratio of the liquid and solid phases to the consumption of sulfuric acid. The autonomy of the temperature from the consumption of circulating phosphoric acid is provided by a compensating device 16. Claims of the invention A method for automatically controlling the extraction process by changing the supply of phosphoric acid to the extractor depending on its consumption, the consumption of raw materials and the ratio of solid and liquid phases in the pulp, supplying sulfuric acid to the extractor depending on its consumption, raw material consumption and the concentration of excess sulfuric acid in the pulp, changes in the magnitude of the vacuum in the vacuum evaporator depending on the rate The treatment in the extractor, the change in pulp removal depending on its level in the extractor and the removal of circulating pulp, characterized in that, in order to increase the productivity and quality of the output product by increasing the control accuracy, the flow rate and density of the pulp are also measured and by sum The indicated parameters and costs of sulfuric and phosphoric acid correct the size of the vacuum, and the supply of phosphoric acid is adjusted for the consumption of sulfuric acid. Sources of information taken into account in the examination 1. USSR author's certificate - S19202, cl. On 01 D 11/02, 1975. 2. Maizel Yu. A. and others. Automation of the production of phosphorus and phosphorus-containing products. M., “Himi, 1973, p. 183-184.