SU1722553A2 - Mixer - Google Patents

Abstract

The invention relates to devices for automatic control of the chemical and petrochemical industry, in particular to devices for preparing a liquid mixture, and allows to expand the functionality by automatically varying the performance of the mixture with a given concentration of the controlled component in the preparation of aggressive, crystallizing, viscous and etc. mixtures and improving the accuracy of determining the concentration of the prepared mixture by eliminating fluctuations in the initial concentration of the monitored component. The device for preparing a liquid mixture additionally contains a flow meter on the line of uncontrolled concentration of flow, a computing unit and a mass flow controller for the prepared liquid mixture, and the output of the node for determining the concentration of the controlled component of the prepared mixture is connected to one of the inputs of the computing unit, the second input connected to the flow meter output of uncontrolled flow, and the output of the computing unit is connected to the input of the mass flow controller of the prepared mixture , controlling the actuator on the line supplying uncontrolled concentration of the stream to the mixer. 1 il. with s

Description

The invention relates to devices for the preparation of a liquid mixture with automatic control and regulation of the concentration of one of the components and is in addition to auth. Mg 997769.

A device containing a mixer, a node for controlling the flow of a monitored component, a unit for determining the concentration of a monitored component, made in the form of a block of thermal sensors mounted together with a mixer, is known.

directly on the process pipeline, the thermal sensors being made in the form of a block of thermocouples and the number of junctions of each of the thermal sensors is directly proportional to the mass flow and heat capacity of the corresponding flow.

The mixer body and the outer surfaces of the thermal sensors are covered with a layer of thermal insulating material, such as polyurethane foam.

A disadvantage of the known device is the inability to vary

Ca

Yu

automatically blend the performance of the mixture with a given concentration of the monitored component in the preparation of aggressive, crystallizing, viscous, etc. mixes.

There is a limit on the maximum throughput of the mixture — the cross section of the ejector nozzle for introducing the monitored component into the process stream. However, within this limitation on the production requirement, it is often important to maintain different blend performance while maintaining a given concentration of one of the components. Direct control of the mass flow rate of the mixture in the case of aggressive, crystallizing, viscous, etc. mixtures is difficult when using the known device.

In addition, variations in the initial concentration of the monitored component affect the accuracy of determining the concentration of the prepared mixture and the stabilization of the mass flow rate of the prepared mixture.

 The aim of the invention is to expand the functionality by automatically1 varying the productivity of the mixture with a given concentration of the controlled component in the preparation of aggressive, crystallizing, viscous, etc. mixtures, as well as stabilization of the mass flow rate of the prepared mixture when the initial concentration of the controlled component fluctuates ..

This goal is achieved by the fact that the flowmeter on the supply line of the uncontrolled concentration of the flow into the mixer, the computing unit and the mass flow controller of the prepared liquid mixture are additionally introduced into the device.

The output of the node for determining the concentration of the controlled component in the prepared mixture is connected to one of the inputs of the computing unit, the second input of which is connected to the output of the flow meter of the uncontrolled flow, and the output of the computing unit is connected through the mass flow controller of the prepared mixture to the actuator on the supply line uncontrolled concentration of the flow in the mixer.

The drawing schematically shows the proposed device.

A device for preparing a liquid mixture contains a housing 1, which is mounted directly in the process line, a mixer in the form of blades 2, successively installed along the course of the flow, a pipe 3 with a controlled

valve 4 for supplying the controlled component, ejector 5 for introducing the monitored component into the process flow, thermocouple unit b installed on the initial mixture flow, thermocouple unit 7 installed on the monitored component flow, thermocouple unit 8 mounted on the finished mixture flow, converters 9 and 10 and the secondary control device 11.

The surfaces of housing 1 and thermocouple blocks 6–8 are thermally insulated with a layer of heat insulating material 12.

The flow of the concentration-uncontrolled flow is measured by a standard flow meter 13. Signals proportional to the concentration of the monitored component in the prepared mixture, and signals proportional to the flow of the uncontrolled flow are implemented by the computing unit 14 connected to the controller (secondary regulating device) of the mass flow of the prepared liquid mixture, which is connected to the valve 16 on the supply line of uncontrolled concentration of the stream to the mixer.

The device works as follows.

Through the process pipeline into the housing 1 under pressure enters uncontrolled concentration stream, such as water. In the zone of the ejector 5, the water flow captures a controlled component, for example sulfuric acid, coming through pipe 3 with a controlled valve 4. In the zone of the blades 2, the flows acquire a turbulent motion and mix. As a result of the thermal mixing effect, the flow temperature of the prepared mixture changes, which is fixed temperature sensors 6-8. The thermo-EMF, arising at the temperature sensors, is converted by converters 9 and 10 into a pneumatic signal, which is fed to the secondary device 11 with a regulating unit.

The effect of the control unit of the secondary device 11 on the valve 4 stabilizes the set value of the concentration of the monitored component.

The dependence of the magnitude of the temperature increase on the change in the concentration of the monitored component is determined experimentally for each mixture by comparison with laboratory tests.

Diluted with a solution of corrosive components (for example, sulfuric acid) are more dangerous in the corrosion process, therefore, direct measurement of the mass flow rate of the prepared mixture is difficult.

In the proposed device, a standard flow meter 13 measures the flow of an uncontrolled flow concentration (non-aggressive, non-corrosive-capable). Signals proportional to the concentration of the monitored component of sulfuric acid in the mixture, and signals proportional to the flow of the uncontrolled concentration of water flow go to computing unit 14, implementing them depending

pgi ggi + m2 TTTF

where mi + rrv2 is the mass flow rate of the prepared mixture, kg / h;

mi - mass flow of uncontrolled flow, kg / h;

T2 - mass flow rate of the controlled component, kg / h;

C is the concentration of the controlled component in the prepared liquid mixture, fractions of a unit.

From the computing unit 14, the output signal goes to the mass flow controller 15, which controls the actuating mechanism (valve) 16 on the flow line of the uncontrolled flow to the mixer,

Thus, by changing the setting of the productivity of the prepared mixture to the mass flow controller 15, the flow rate of the prepared mixture is affected by the flow rate of water,

This results in a more dilute solution of the prepared mixture, then the device operates according to the prototype scheme, and valve 4 changes the flow rate of the component being monitored, which leads to the restoration of the value of a given concentration of the component being monitored in the mixture being prepared.

Example. Continuous preparation of a solution of sulfuric acid in the production of styrene-butadiene rubber at Sumgait plant CK.

The specified capacity tz 16000 kg / h; given concentration Ci is 0.015; the concentration of the initial sulfuric acid C2 O., 90-0.96 wt.%; the amount of heat released upon dilution with 1 kg-mole of 100% H2SO4 to 1.5 wt.% solution of H2 SO4, - Q 18089 kcal / kg-mol (1); the amount of heat released upon dilution with 1 kg-mole of 100% H2SO4 to 96% by weight (1) is Q2 2256 kcal / kg-mole; the same, up to 90 wt.%. (1) -Oz 4986 kcal / kg-mol. We calculate the absolute and relative errors in determining the concentration of the prepared 1.5 wt.%

solution when changing the concentration of the original 96% sulfuric acid to 90%.

1, The temperature difference resulting from the dilution of 96% N25Cm to 1.5%

And P, where gp5 is the mass of 1.5% ms Srz

of a solution of LBSM when diluted with 1 kg-mol Q4 Qi-Q2 18089-2256 15833 kcal / kg-mol,

2. When diluted with 1 kg-mol 96% H2S04 to 1.5% H2SCM solution

QQ

yo 6533kg Cpz 0.985,

GP5:

0.015

where ms is the mass of a 1.5% aqueous solution of H23Sm at a dilution of 1 kg / mol H2S04J

Срз - heat capacity of 1.5% H2S04 solution

l t- - 15833 ncOr Atl 6533-0.985 2 46С-3. When diluted with 1 kg-mol 90% H2SO4 to 1.5% H2SO4 solution and maintain the temperature difference by diluting At 2.46 ° C

Q4 Qi - Oz - 18089 - 4986 - 13103 kcal / kg-mole NazSm

 SIM where M is the amount of kg-mole of 100% H2S04

M

2,46 € 533 0,985

 1,208 kg-mole

13103

H2S04

or amount of 100% sulfuric acid (in kg)

gp4 1,208 -98 118,38 kg.

4. Concentration of the prepared solution.

118.38

C2

6533

100 1.81 wt.%.

5, Absolute error in the preparation of 1.5 wt.% Solution of sulfuric acid

4b. 1.81 - 1.5 0.31 wt.%.

6. The relative error in the preparation of 1.5 May. % sulfuric acid solution

5ot

0ab.

  -100 20%.

1.5 1.5 Measurement and regulation of the mass flow rate of the prepared 1.5% solution of sulfuric acid from the initial 96% sulfuric acid,

1. The required amount of 100% H2SO4 to prepare a solution

those tzs1 16000 -0.015 240 kg / h.

2. Consumption of 96% H2SO4 for the continuous preparation of a 1.5% solution of H25C

GP7:

t H-250

3. Water consumption for dilution of 96% H2S04

mi1 - (1-C) tz - (1-0.96) - (1-0.015) - - {16000-0.04 250) - 0.985 16000 -10 - -15750 kg / h.

mi

one

 15750 15750 С 1 - 0.015 0.985

4. tz1

-15990 kg / h

5. The relative error of the method for determining the mass flow rate of the prepared solution

L .. yyura. , 063%

6. When changing the initial concentration of sulfuric acid from 96 to 90%, the required amount of 90% H2SO4 to prepare a solution

gleM 240 108 0,900,90

GO8:

322.1 kg.

hh

15678 / 1-0,0181 15697

7. Water consumption for dilution of 90% H2.S04

mi (1-C2) tz - (1-0.9) TV (1-0.0181) - - (16000-0.1 322.1) 15710-32 - 15678 kg / h.

6 Mass flow rate of the prepared solution

J.-J2L

1-C2

kg / h

9. To maintain the concentration of the prepared solution of 1.5 wt.% When changing the initial concentration of sulfuric acid from 96 to 90 wt.%.

Water consumption for reading will be: mi -. m3 (1-Ci) - 15967 (1-0.015) 15967 -0.985 15727 kg / h.

10. The relative error of the method for determining the mass flow rate of the prepared solution

-.

 0.2%

The overall relative error of the complex of technical means when regulating the mass flow rate of the prepared solution according to the proposed technical solution

0

five

0

five

d oJ +: 1.52 + 12 + 2.52

 0.04 + 2.25 + 1 + 6.25 954 3.09 “3%.

Thus, controlling the mass flow rate of the prepared 1.5 wt.% Solution of sulfuric acid by changing the flow rate of water supplied to the preparation, allows to compensate for the variation of the initial concentration of sulfuric acid from 96 to 90% and maintain the concentration of the prepared solution with an accuracy comparable to that of laboratory analysis.

The functionality of the device is expanded by automatically varying the productivity of the finished mixture with a predetermined concentration of the controlled component, which is especially important in the production of aggressive, crystallizing, viscous, etc. in the preparation. mixes.

In addition, the use of the proposed device makes it possible to stabilize the mass flow rate of the prepared liquid mixture when the initial concentration of the controlled component fluctuates.

Claims (1)

The invention of the device for the preparation of a liquid mixture according to ed. St. Ns 997769, characterized in that, in order to extend the functionality by automatically varying the productivity of the mixture with a given concentration of the controlled component in the preparation of aggressive crystallizing, viscous, etc. mixtures, as well as stabilization of the mass flow rate of the mixture being prepared when the initial concentration of the monitored component fluctuates, the device additionally contains a flow meter and an actuator on the flow line of the uncontrolled concentration of the flow into the mixer, the computing unit and the mass flow controller of the prepared liquid mixture, the output of the node determining the concentration of the controlled component a4 V 552-t- (56z + 572-l- 58T, where 5з-0.2% (method error); 5b w 1.5% (standard flow meter error); 5% H (error of the dividing block); dv «| 2.5% (regulator error). In the prepared mixture, this is connected to one of the inputs of the computing unit, the second input of which is connected with the flow meter of an uncontrolled flow concentration, and the output of the computing unit is connected through a mass flow controller to the actuator on the uncontrolled flow line to the mixer.