SU761987A1 - Ammonia sulphate production process automatic control apparatus - Google Patents

Description

The invention relates to devices for automatic control of the process of obtaining ammonium sulfate in centrifuges and can be used in the chemical and coking industry and non-ferrous metallurgy.

Upon receipt of a crystalline product from a saturated solution, for example, ammonium sulfate in the interaction of ammonia, coke oven gas and sulfuric acid, the pulp containing the crystals of the produced salt and the mother liquor are fed into a centrifuge, where centrifugal force separates the crystals from the mother liquor. The mother liquor (centrifugal) is returned to the crystallizer through an intermediate tank - a pan of reverse currents. In the centrifuge, the crystals are washed with water (vapor condensate) to remove free acid (alkali) from the surface of the crystals. The quality of the produced crystalline salt, along with other indicators, is determined by the amount of free acid (alkali) and should not exceed a certain value for this variety.

2

A device is known for automatically controlling the process of producing ammonium sulphate in a plant comprising a crystallizer and a centrifuge containing pulp density, flow rate and pH sensors, ₅ combined with a computing unit [1].

A disadvantage of this device is not optimal regulation of the centrifuge operation, which leads to a decrease in the quality of the crystalline salt produced with an insufficient amount of washing water, and with an excessive amount of washing water - to a violation of the crystallizer water regime, which requires additional energy costs for evaporation of excess water. Such regulation is obtained iz ^ a lack of operational inverse ^15-coupling of the results prrmyvki crystals.

The purpose of the invention is to reduce the water consumption for washing the sulfate and reduce, thereby, energy consumption.

20 The goal is achieved by the fact that

The device is equipped with sensors for water flow and centrifugal pH, measuring unit, regulator, setting device and actuator installed on the line

761987

water supply to the centrifuge and associated with the output of the regulator, the input of which is connected to the setpoint generator and the measuring unit, the latter being connected to the flow and pH sensors and to the computing unit.

From the material balance of the centrifuge for acid we have:

about _k = οΐ-οί,

where OK - the amount of acid in the crystalline product per unit of time

O * - the amount of acid in the pulp per unit of time (consumption);

OK - acid consumption in the centrifugal.

The amount of acid in the pulp is determined by:

Ok - (θη θτβ) ^{, η} ι 1,

• where OO, O _{t6 —} costs of pulp and solid pulp product;

πΐι is the weight fraction of the acid in the liquid phase.

Similarly

О _к = (О „—О _т8 + О«) - td, where 0 $ is the flush water consumption;

t a is the weight fraction of the acid in the centrifugal.

.Then

Ok = (O _p - O _tv ) -t ₁ - (Ό „- Ote + Ov) ·· ¹¹ ! The weight fraction of acid (acidity) is estimated by pH, as measured by the pH meter.

Using the methods of planning an experiment, the indicated material balance equation can be represented with a sufficient degree of accuracy in the form of a polynomial:

О _к = В о + В ι · О η + В г - О _τβ + В з рН _п - - В 4'О c – Βδ-ρΗη,;

Where B o, B ί, B & - control factors

Bz, B d, B 5 regressions (they have a definite value for a given acid and the salt produced);

pH „, pH„ - acidity of the pulp and centrifugate.

The drawing shows a device for the automatic control of the process of obtaining ammonium sulfate.

The device contains a crystal receiver 1, a centrifuge 2, an intermediate tank 3 reverse currents, a sensor 4 and a secondary device 5 measuring the density of the pulp, a sensor 6 and the secondary device 7 measuring the flow rate of the pulp, the sensor 8 and the secondary device 9 measuring the pH of the pulp, measuring 10 solid product in the pulp , a sensor 11 and a secondary device 12 of a centrifugal pH meter, a sensor 13 and a secondary device 14 of a water flow meter, a measuring unit 15, a regulator 16, a setting device 17 and a control valve 18.

The pulp through the crystal receiver 1 enters the centrifuge 2, where the washing water is simultaneously supplied. Centrifuge from centrifuge 2 enters the mold

four

through an intermediate tank of 3 reverse currents, into which the mother liquor settled in the crystal receiver also enters. The density, flow rate and acidity of the pulp are measured respectively by sensors 4, 6, 8 and secondary instruments 5, 7, 9, the signals from which are fed into the meter 10 of the amount of solid product in the pulp. The acidity of the centrifugal is measured by the sensor 11 and the secondary device 14. The signals from the devices 7, 9, 12 and 14 are sent to the measuring unit 15, in which the dependence is realized:

О к - В о + В ι · О _п + В л · + В ₃ ЬН _п - - В 4 <3 "- В 5 · ρΗ _π

The signal is proportional to the content of acid in the product from the output of the measuring unit is fed to the input of the regulator 16, which simultaneously receives a signal from the setting device 17. From the output of the regulator, the signal goes to the regulating valve 18 installed on the water supply line.

Thus, the acidity of the crystalline product, set by the setter, is automatically maintained with a minimum flow rate of wash water.

The use of the proposed automatic system in comparison with the known one provides an improvement in the technical and economic indicators of the production of crystalline salts as a result of reducing energy costs and improving the quality of the crystalline product.

The economic effect from the introduction of the proposed automatic system will be 12 thousand rubles. per year with a gas flow of 150-200 thousand m ² per hour.

Claims (1)

Claim Device for automatic control of the process of obtaining ammonium sulfate in the installation, comprising a crystallizer and a centrifuge, containing density, flow and pH sensors, connected to a computing unit, characterized in that, in order to reduce the water consumption for washing the sulfate and reduce, thereby, energy consumption , it is equipped with sensors for water flow and pH of the centrifugal, measuring unit, regulator, setting device and actuator installed on the water supply line to the centrifuge and connected to the output of the regulator torus, whose input is connected to the measurement unit and setting device, the latter being connected to the flow sensors and the pH and to the computing unit.