SU1530568A1 - Method of automatic control of process of decomposition of fluorspar in ovens - Google Patents

Abstract

The invention relates to the automation of technological processes, namely the automation of the decomposition of fluorspar in tube furnaces with external heating, can be used in the chemical industry in the production of hydrogen fluoride and allows you to increase the degree of decomposition of fluorspar and reduce the content of sulfuric acid in the solid reaction product. The method involves calculating the optimal temperature profile of the reaction mass in the furnace based on the measured flow rates of the liquid and solid flows at the furnace inlet, the temperature of the reaction gas at the furnace exit, the composition of the liquid flow at the furnace entrance and the solid reaction product at the furnace exit. Comparing it with the measured temperature profile and, if there is a deviation, the calculation of the required temperature profile in the zones of the heating chamber of the furnace from the measured values of the flow rates of the liquid and solid flows at the furnace inlet, the composition of the liquid flow and the calculated optimum temperature profile of the reaction mass in the furnace and the stabilization of this temperature profile in zones of the heating chamber of the furnace by changing the heat supply to these zones. 1 il.

Description

The input flow rates are stabilized by regulator 1 and dispenser 2. The temperatures of the heating chamber zones are measured by thermocouples, the thermoelectric power from which regulators 6-8 come to the computing device. Regulators 6-8 provide by means of electric heaters 9-11 only maintaining the temperatures of the heating chamber zones corresponding to the specified values, but do not maintain the desired temperature profile of the reaction mass, due to destabilizing factors (deposition of reaction products on the inner surface of the drum, changes in composition and costs of input process streams)

The temperatures of the reaction gas and the reaction mass are measured by sensors 12-13. The composition of the input process flows and the blade is monitored by sensors 1b and 17c.

In addition to the listed technological parameters, data on the composition of the fluorescent lunaTa are entered into the computing device.

The method is implemented as follows.

Using the input information, the computing device calculates the optimal temperature profile of the reaction mass.

To find the optimum temperature values of the reaction mass, an optimization problem is solved, for example, by scanning, in order to minimize the residual content of calcium fluoride and sulfuric acid in the solid (dump) of the furnace at the corresponding values for the input and regime parameters.

The set of regression equations is used as a mathematical model of the mapping dependence between the adjustable parameters and the r-tti regulating effects, input and mode parameters.

The first three regression equations establish the relationship between the temperature tpj, the reaction gas, the residual content of sulfuric acid Xn, calcium fluoride XQJF, in the dump, and the consumption of fluorspar and mixture of acids G, the temperatures of the reaction mass in the first zone t, in the second zone t ij and the third zone tj and fluoride concentrations

hydrogen. and sulfuric acid in a mixture of acids:

one

X и ,, 2 + 0, ЗСсаР, -65.5С „at / С 4, iSO, + 11.7 (С„, с, 04 / СсаР,) -t-0.03t +

-bO, 006 (GcQF) -32.1 (GH 504 / f CaF,) + 0, OOz4 + 0.009CHSR, -18.8t, jCnF /

 - 1t ((GH s04 / CaF 2 + 0.14t (GH-iO, 0, / GcaF i (1)

tp., 152.1-169, AP Hf / CHiSOA- -31.5 (Gn S04 / GcQF5),, 05t3-t4-0, 02 (GcoF, 2 (GH, sO, / GCqF / - - +0, , + 3,7Gc, F (, / / Gcc. ,,,, 9tuCHF / CH c, 04 + 24,5t5CHF / CH, S04-7, 9t (GH, c, 0, / GcoFn) V

(2)

Xc "f 1, H-0.02Gcaf +0.29 (GH,", 04 / / GcoP) -0.01t, + 0.01 (GcQF) -4, 7 (0 H, ", 04 / GcqF, ) + 0.00034 + 4-b

+ 0,, OOt, Gcof „-0,

/ Sleep Code

(3)

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Restrictions are: a limit on the mass flow rate of input flows Gcaf 0.21-0.29; GH5S04 0.22-0.40; restriction on operating parameters of the furnace t, 50-100; t5 140-210; t3 210-270; tnp 580-630; 570-600,4, gr. 460-560, the limit on the temperature of the reaction gas

tp.z 160-190,

restriction on the residual content of calcium fluoride and sulfuric acid in the dump 0.002-0.02; -Hnos, o. 0.005-0.15 | as well as characteristics of the composition of input streams:

, 068-0.089; CcaFa 0.95-0.96;

Sn, 504 0 89-0 92.

The calculated and actual temperatures of the reaction mass are compared with each other. If there is a difference between them, corrections for the temperatures of the zones of the heating chamber of the furnace are calculated.

To determine these corrections, for example, the following three equations can be used, which reflect the relationship between the temperature of the reaction mass at 3OHaM (t4, t, t)

and the consumption of fluorspar and sulfuric acid, the concentrations of hydrogen fluoride CHF and sulfuric acid in the input flow and the temperatures of the heating chambers of the first zone, the second zone t

third zone

t, 92.2-0.5Gc, F, -0.28t, 2p-0.7tjtp-657, 6 (GH, so / GcaF,) + 0.007t ep-5, 3G (p С HF / С л04 + 6, 2G (G n, 2 50 /, /

/ GcaFa 0 0 i pCcaF "-3,8t, gr (

It helps to increase the degree of sulfuric acid decomposition of fluorspar to 97.5– 98.5% against 90–95% (by a known method), while simultaneously reducing the content of sulfuric acid in mold plaster to –E% against 13–20% and reducing the expenditure coefficients for hydrofluoric acid. spar varieties FF95A up to 2.17-2.20 tons versus 2.26-2.39 tons, as well as sulfuric acid in terms of monohydrate 3 | 0 tons versus ZL tons per 1 ton of hydrogen fluoride.

/ G

);

t, 209.8-0.18tri2p-0.07 (GeaF,) - U03 (, / Gcaf f O, -131, 6GtaF, CUF / C n, 504 51, 6t (ipCHF / / Сн,.,, ( five)

tr236 + 0,002G 4,% 04 / GcaF -0.7t, jp-b

+ 0,46t52p -0,19t: a, 2p-0,07tQ2pGcaF + + 0, OSY2, yyrr / CH gOD (6)

The computing device generates the corresponding signals at the output that change the controller settings to adjust the temperatures of the heating chamber zones. With a change in the settings of temperature controllers of the heating chamber, the amount of heat input changes. Consequently, there is a reduction in the mismatch between the optimal temperature profile of the reaction mass and the actual temperature profile of the reaction mass.

The advantage of the proposed method in comparison with the known ones is that the optimum temperature profile of the reaction mass is determined for each predetermined point in time and is continuously compared with the actual, and correction is carried out depending on the ratio of the corresponding calculated and measured temperatures of the reaction mass. thermal decomposition of fluorspar can be stabilized with a sufficiently high accuracy and maintained constant during fluctuations with tava and expenses input process streams.

In the production of hydrogen fluoride on furnaces with external electric heating, the proposed method allows (4)

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Claims (1)

Invention Formula A method for automatically controlling the decomposition of fluorspar in furnaces, including controlling the flow of liquid and solid flows into the furnace, the temperature profile in the zones of the heating chamber of the furnace by changing the heat input to these zones and measuring the composition of the solid reaction product at the furnace output, characterized in that increasing the degree of decomposition of fluorspar and reducing the content of sulfuric acid in the solid reaction product; additionally, the temperature profile of the reaction mass in the furnace is measured; the temperature of the reaction The measured gas flow rate of the liquid and solid flows at the furnace inlet, the temperature of the reaction gas at the furnace exit, the composition of the liquid flow at the furnace inlet and the solid reaction product at the furnace exit, calculate the optimum temperature profile of the reaction mass in the furnace; compare it with the measured value; and if the calculated optimum temperature profile of the reaction mass in the furnace deviates from the measured value, calculate the required temperature The profile in the zones of the heating chamber of the furnace according to the measured values of the flow rates of the liquid and solid streams at the inlet of the furnace, the composition of the liquid stream and the calculated optimum temperature profile of the reaction mass in the furnace establish this calculated required temperature profile in the zones of the heating chamber of the furnace by changing the heat input to these zones. Reactionary fas Cbinuwu project-ch I JKuffxyu project