RU2005726C1 - Method for automatic control of the process of preparing hydrocarbon blend in the synthetic rubber manufacture - Google Patents

Abstract

FIELD: automation of technological process. SUBSTANCE: process of preparing hydrocarbon blend is controlled by a control of the blend composition. The control involves: measuring the consumption of monomers and the consumption of a return fraction on the preparation of the blend; measuring the blend level in the intermediate tank and the blend consumption on the polymerizing process; regulating the consumptions of monomers and of the return fraction on the preparation of the blend; determining a preset blend consumption in the intermediate tank; actuating of controllers of monomer consumption and of the return fraction consumption as a function of the level of a purified return fraction in a surge tank and of the blend composition. According to the method the blend level in the intermediate tank is additionally measured. The blend consumption on the polymerizing process is measured. The solvent consumption on the preparation of the blend is measured and regulated. A preset value of the blend consumption in the intermediate tank is determined as a function of the blend consumption on the polymerizing process and of the blend level in the intermediate tank. A concentrations ratio of the monomers in the blend is determined. The concentration ratio of the solvent and of the monomers in the blend is determined. A ratio of the purified return fraction consumption on the preparation of the blend to the blend consumption in the intermediate tank is determined. A ratio of the first monomer consumption on the preparation of the blend to the blend consumption in the intermediate blend is determined. A ratio of the second monomer consumption on the blend to the blend consumption in the intermediate tank is determined. A ratio of the solvent consumption on the preparation of the blend and the blend consumption in the intermediate tank is determined. A preset ratio value of the second monomer consumption in the intermediate tank is determined. A preset ratio value of the purified return fraction consumption on the preparation of the blend to the blend consumption in the intermediate tank is determined. A preset ratio value of the first monomer consumption on the preparation of the blend to the blend consumption in the intermediate tank is determined. A preset ratio of the solvent consumption on the preparation of the blend to the blend consumption in the intermediate tank is determined. Actuate a controller of the purified return fraction consumption on the preparation of the blend, the controller of the first monomer consumption on the preparation of the blend, a controller of the second monomer consumption and a controller of the solvent consumption on the preparation of the blend. EFFECT: enhanced accuracy of automatic control of the blend composition ( the concentrations ratio of monomers in the blend and the concentrations ratio of the solvent and of the monomer in the blend ) and reduced costs on the manufacturing one ton of the rubber.

Description

 The invention relates to the field of automation of technological processes for the production of synthetic rubbers and can be used in the chemical industry, for example, in the production of low molecular weight divinylpiperylene rubber SKDP-N.

 A known method for automatically controlling the process of preparing a hydrocarbon charge in the production of synthetic rubber by measuring the concentration of monomer in the charge, charge consumption, regulating the flow of monomer in the return fraction for the preparation of the charge, determining from a given concentration of monomer in the charge a predetermined ratio of the flow rate of the monomer and return fraction for cooking charge, correction of the specified ratio by the deviation of the actual concentration of monomer in the charge from the set value and the impact on the costs of the monomer and the return fraction depending on the charge consumption and the adjusted predetermined ratio of the costs of the monomer and return fraction.

 In this method, when forming control actions for the monomer and return fraction flow controllers on the charge preparation, the charge level in the intermediate charge storage tank and the return fraction level in the buffer tank are not taken into account and are not regulated. The known method also does not provide for the regulation of the ratio of monomers in the charge, but provides for the impact on the flow rate of only one monomer.

 The known method also does not provide for the adjustment of a predetermined ratio of the concentration of monomers in a charge and a predetermined ratio of the concentration of solvent and monomers in a charge, which impairs the accuracy of controlling the composition of the charge when two or more monomers are fed to the preparation of the charge.

 The closest in technical essence to the present invention is a method for automatically controlling the process of preparing a hydrocarbon charge in the production of synthetic rubber by automatically controlling the composition of the charge, measuring the flow rate of the monomer and the return fraction for the preparation of the charge, the level of the purified return fraction in the buffer tank, controlling the consumption of monomers and return fraction on the preparation of the mixture, changes in the control actions of the flow control monomer and return fraction depending on the level of the purified return fraction in the buffer tank and the composition of the charge.

 In the known method, when forming control actions, the charge level in the intermediate tank is not taken into account and is not regulated, and the ratio of monomers in the charge is not provided for.

 The known method provides for the effect on the flow rate of only one monomer and does not provide for the adjustment of the given ratio of the concentration of monomers in the charge and the given ratio of the concentrations of solvent and monomers in the mixture, which impairs the accuracy of the regulation of the composition of the charge when two or more monomers are fed to the preparation of the mixture and ultimately negatively affects the quality of the resulting rubber.

 The known control method does not provide for the measurement and regulation of the flow rate of the solvent for the preparation of the charge, the formation of the control action of the flow rate controller of the solvent for the preparation of the charge.

 In addition, in cases where not one, but two or more monomers are fed to the preparation of the charge, it is advisable to use not the ratio of the monomer and return fractions as the intermediate controlled variable, but the ratio of the costs of each of the flows and the charge consumption, i.e. the ratio of the costs of the return fraction for the preparation of the charge and the charge in the intermediate tank, the ratio of the costs of the first monomer for the preparation of the charge and the charge in the intermediate tank, the ratio of the costs of the second monomer for the preparation ihty and charge in the intermediate tank and the ratio of solvent cost of preparing the charge and the charge in the intermediate tank.

 The essence of the invention lies in the fact that according to the method for automatically controlling the process of preparing a hydrocarbon charge in the production of synthetic rubber, for example, low molecular weight divinylpiperylene rubber SKDP-N, which consists in automatically controlling the composition of the charge, measuring the consumption of monomers and the return fraction for preparing the charge, the level of purified return fractions in the buffer tank, regulating the flow rates of the monomer and the return fraction for the preparation of the mixture, changing the control effect depending on the level of the purified return fraction in the buffer tank and the composition of the charge, they additionally measure the charge level in the intermediate tank, measure and regulate the solvent flow rate for preparing the charge, determine the set value of the charge flow into the intermediate tank, depending on the flow rate charge for polymerization and the level of the charge in the intermediate tank, determine the ratio of the concentration of monomers in the charge, determine the ratio of the concentrations of solvent and mono jers in the charge. The ratio of the costs of the purified return fraction for the preparation of the charge and the charge to the intermediate tank, the ratio of the costs of the first monomer for the preparation of the charge and the charge to the intermediate tank, the ratio of the costs of the second monomer are determined by the costs of the purified return fraction, the first monomer, the second monomer and the solvent for preparing the charge on the preparation of the charge and charge into the intermediate tank and the ratio of solvent consumption for the preparation of the charge and charge into the intermediate tank.

 The predetermined ratio of the flow rates of the second monomer for the preparation of the charge and the charge into the intermediate tank is determined from the initial value of this ratio and the level of the purified return fraction in the buffer tank. A control action is generated for the flow rate regulator of the second monomer depending on the value of the ratio of the flow rates of the second monomer on the preparation of the charge and the charge into the intermediate tank, the set value of this ratio and the set value of the charge flow into the intermediate tank.

 The set value of the ratio of the concentration of monomers in the mixture and the set value of the ratio of the concentrations of solvent and monomers in the mixture are adjusted depending on the deviations of their current values from those set by the operator-technologist.

 The set value of the ratio of the costs of the purified return fraction for the preparation of the mixture and the mixture into the intermediate tank is determined from the adjusted set value of the ratio of the concentration of monomers in the mixture and the adjusted set value of the ratio of the concentration of solvent and monomers in the mixture.

 Determine the set value of the ratio of the first monomer to prepare the mixture and the mixture into the intermediate tank using the adjusted set value of the ratio of monomer concentrations in the mixture, the adjusted set value of the ratio of solvent to monomer concentrations in the mixture and the set value of the ratio of the purified return fraction to the charge and charge into the intermediate tank.

 The predetermined value of the ratio of the costs of the solvent for the preparation of the charge and the mixture into the intermediate tank is determined by the adjusted set value of the ratio of the concentrations of the solvent and the monomers in the charge, the set value of the ratio of the costs of the return fraction for the preparation of the mixture and the charge into the intermediate tank.

 A control action is formed for the flow regulator of the purified return fraction on the preparation of the charge, depending on the value of the ratio of the costs of the purified return fraction on the preparation of the charge and the charge in the intermediate tank, the set value of this ratio and the target value of the charge in the intermediate tank.

 The control action of the flow rate controller of the first monomer on the preparation of the charge is formed depending on the ratio of the flow rates of the first monomer for the preparation of the charge and the charge into the intermediate tank, the set value of this ratio and the target value of the charge to the intermediate tank.

 The control action of the solvent flow regulator on the preparation of the charge is formed depending on the value of the ratio of the solvent consumption on the preparation of the charge and the charge into the intermediate tank and the set value of this ratio and the set value of the charge flow into the intermediate tank.

 The combination of new control methods, in combination with the known ones, provides an increase in the accuracy of automatic control of the composition of the mixture (the ratio of the concentrations of monomers in the mixture and the ratio of the concentrations of solvent and monomers in the mixture) and a reduction in the cost of producing a ton of rubber. This occurs for the following reasons.

 Measurement and regulation of the charge level in the intermediate tank enables the control system to quickly respond to changes in this level and prevent large deviations of the charge level in one direction or another.

 This, on the one hand, provides a reserve for management, i.e., the possibility of changing the costs of the purified return fraction, monomers, solvent, and the charge consumption for polymerization both in the direction of decreasing and increasing.

 On the other hand, by maintaining the level within predetermined limits, the exclusion of such situations when overfilling or emptying of the tank occurs is achieved. Such situations would lead to sharp changes in these costs or to a halt in the polymerization process. Both that and another negatively affect the accuracy of regulation of the composition of the mixture and will lead to an increase in the cost of obtaining a ton of rubber.

The proposed automatic control method involves adjusting the predetermined ratio of the concentration of monomers in the mixture and the predetermined ratio of the concentrations of solvent and monomers in the mixture, which significantly improves the accuracy of regulation of the composition of the mixture when two or more monomers are fed to the preparation of the mixture and ultimately positively affects the quality of the rubber obtained. This is because, in this case, when the ratio of the monomer concentrations in the charge deviates from the set value, the set value of the ratio of the first monomer consumption for the preparation of the charge and the charge into the intermediate tank (S _dhz ), as well as the specified the value of the ratio of the costs of the purified return fraction for the preparation of the charge and the charge in the intermediate tank (S _VSHZ ). And since the determination of the ratios S _dhz , S _hsh is based on the material balance of the _mixture preparation unit, the adjustment will eliminate the deviation, and this will happen in an optimal way.

Similarly, the correction of the specified ratio of the concentration of solvent (S _W ) and monomers in the charge is carried out. In this case, the change will affect not only the relation S _w3w , but also S _w3w , S _w3w (formulas 19, 20, 21).

The proposed control method also provides for the measurement and regulation of the solvent flow rate for the preparation of the charge and the formation of the control action of the solvent flow rate regulator for the preparation of the charge, which makes it possible to change the ratio S _tf .

 As an intermediate value in the proposed control method, it is not the ratio of the costs of the monomer and the purified return fraction, but the ratio of the costs of each of the flows and the charge rate, i.e., the ratio of the costs of the purified return fraction for the preparation of the charge and the charge into the intermediate tank, the ratio of the costs of the first monomer for the preparation of a charge and a charge in an intermediate tank, the ratio of the costs of the second monomer for the preparation of a mixture and a charge in an intermediate tank and a ratio of the solvent on the preparation of the mixture and the mixture in the intermediate tank. These ratios are more stable than, for example, the ratio of the flow rates of the monomer and the purified return fraction, and to a greater extent depend on the regulated values - on the ratio of the concentrations of monomers in the charge and the ratio of the concentrations of solvent and monomers in the charge.

 The invention is illustrated by an example of its implementation and the drawing, which shows a system that implements this method of automatic control.

 The diagram shows: a mixer 1, an intermediate tank 2 for storing the charge, a pump 3, a process unit 4 for polymerization and degassing, a distillation column 5, a buffer tank 6 for storing the return fraction, a pump 7, a control computer complex (UVK) 8, a level 9 sensor the charge in the intermediate tank 2, the charge flow sensor 10 for polymerization, a chromatograph 11, the sensor 12, a regulator 13 and a valve 14 for controlling the flow rate of the return fraction for the preparation of the charge, a sensor 15, a regulator 16 and a valve 17 for regulating the flow of solvent to the charge preparation, a sensor 18, a regulator 19 and a valve 20 for regulating the flow rate of the first monomer (divinyl) for preparing a charge, a sensor 21, a regulator 22 and a valve 23 for regulating the flow rate of the second monomer (piperylene) for preparing the charge and a sensor 24 for the return fraction in the buffer capacity 6.

 Four streams are fed to the preparation of the charge: the stream of the return fraction (crude) from the polymerization and degassing unit 4, the stream of the first monomer (divinyl), the stream of the second monomer (piperylene), the stream of solvent (toluene).

 The purified return fraction, the first monomer and solvent are fed to a volumetric mixer 1. The second monomer is fed to the distillation column 5. The return fraction from the polymerization and degassing unit is also fed to this column. In the column 6, the return fraction is purified (regenerated) and the second monomer is purified. The purified return fraction containing the solvent, the first and second monomers, a small amount of impurities, is fed from the column 5 into the buffer tank 6.

 The purified return fraction from the buffer tank 6 is pumped to the mixer 1 by the pump 7, into which the first monomer and solvent are also fed.

 In some cases, a scheme can be applied in which the second monomer is supplied not to distillation column 5, but to a volumeless mixer 1. The proposed automatic control method can be applied without changes.

 The prepared hydrocarbon mixture flows from the mixer 1 into the intermediate tank 2, from where it is pumped to the polymerization and degassing unit 4, where the finished product is obtained - synthetic rubber.

 A method for automatically controlling the process of preparing a hydrocarbon charge in the production of synthetic rubber is as follows.

 Using chromatograph 11, chromatographic analysis of the hydrocarbon charge is carried out. Sampling for chromatographic analysis is carried out after mixer 1. According to the results of chromatographic analysis of the mixture, the concentration of monomers in the mixture and the concentration of solvent in the mixture are determined.

 The flow rates of monomers and the purified return fraction for the preparation of the charge, the level of the purified return fraction in the buffer tank 6, the charge consumption for polymerization are measured. Regulate the costs of the monomer and the return fraction for the preparation of the mixture.

 Additionally measure the level of the charge in the intermediate tank 2, the charge of the charge for polymerization, measure and control the flow of solvent for the preparation of the charge.

где F_шпi - расход шихты на полимеризацию, кг/ч; Δ₂ - зона свободного изменения уровня шихты в емкости 2, % ; в этой зоне работает регулятор уровня с заниженными настройками;
H_2i, H_2з - текущее и заданное значение уровня в промежуточной емкости 2, % ; E_2i - рассогласование между текущим и заданным значением уровня в промежуточной емкости 2, % ;
Δt - дискретность формирования и выдачи управляющих воздействий, ч;
К₁, К₂, К₃, К₄ - настоечные параметры.Determine the set value of the charge flow into the intermediate tank 2 (F _si ) depending on the charge consumption for polymerization and the charge level in the intermediate tank 2:
E _2i = H _2i - H _2з (1)
F _wzi =

where F _spi - charge consumption for polymerization, kg / h; Δ ₂ - zone of free change in the level of the charge in the tank 2,%; in this zone, a level control with low settings works;
H _2i , H _2z - current and set value of the level in the intermediate tank 2,%; E _2i - the mismatch between the current and the set value of the level in the intermediate tank 2,%;
Δt - discreteness of the formation and issuance of control actions, h;
K ₁ , K ₂ , K ₃ , K ₄ - tincture parameters.

, (4)
K_тмi=

, (5) где С_д, С_п, С_т - соответственно концентрация первого мономера (дивинила), второго мономера (пиперилена), растворителя (толуола) в шихте, масс доли; К_дпi - соотношение концентраций мономеров в шихте;
К_тмi - соотношение концентраций растворителей и мономеров в шихте.Determine the ratio of the concentrations of monomers in the mixture and the ratio of the concentrations of solvent (toluene) and monomers in the mixture;
K _dpi =

, (4)
K _tmi =

, (5) where С _d , С _p , С _t are respectively the concentration of the first monomer (divinyl), the second monomer (piperylene), solvent (toluene) in the charge, mass fraction; To _dpi - the ratio of the concentrations of monomers in the mixture;
To _tmi - the ratio of the concentrations of solvents and monomers in the mixture.

, (6)
^Sдшi⁼

, (7)
S_пшi=

, (8)
^Sтшi⁼

, (9) где F_вi - текущее значение расхода возвратной фракции на приготовление шихты, кг/ч;
F_дi - текущее значение расхода первого мономера (дивинила) на приготовление шихты, кг/ч;
F_пi - текущее значение расхода второго мономера (пиперилена) в ректификационную колонну (на приготовление шихты), кг/ч; F_тi - текущее значение расхода растворителя (толуола) на приготовление шихты, кг/ч.The ratio of the costs of the purified return fraction for the preparation of the charge and the charge to the intermediate tank, the ratio of the costs of the first monomer for the preparation of the charge and the charge to the intermediate tank, the ratio of the costs of the second monomer for preparation charge and charge into an intermediate tank, the ratio of solvent consumption for the preparation of a charge and charge into an intermediate tank:
S _lsi =

, (6)
^S dshi ⁼

, (7)
S _pshi =

, (8)
^S tshi ⁼

, (9) where F _вi is the current value of the flow rate of the return fraction for the preparation of the mixture, kg / h;
F _di - the current value of the flow rate of the first monomer (divinyl) for the preparation of the mixture, kg / h;
F _pi - the current value of the flow rate of the second monomer (piperylene) into the distillation column (for the preparation of the charge), kg / h; F _ti - the current value of the consumption of solvent (toluene) for the preparation of the mixture, kg / h

S_пшзi=

sign E_6i,

где Н_6i, H_6зi - значение уровня возвратной фракции в буферной емкости и его заданное значение, % ;
Н₆ ^min1, H₆ ^max1 - минимальное и максимальное допустимые значения уровня, при нарушении которых включается регулятор уровня в буферной емкости, % ; E_6i - рассогласование между значением уровня возвратной фракции в буферной емкости 6 и его заданным значением, % ; S_nшзо, S_nшзi - начальное и заданное значение соотношений расходов второго мономера на приготовление шихты и шихты в промежуточную емкость 2; К₅, К₆, К₇ - настроечные параметры.A predetermined value of the ratio of the flow rates of the second monomer for preparing the charge and the charge into the intermediate tank is determined from the initial value of this ratio and the level of the purified return fraction in the buffer tank 6;
H _{6 zi} =

S _pshzi =

sign E _6i ,

where H _6i , H _6i - the level value of the return fraction in the buffer tank and its predetermined value,%;
H ₆ ^min1 , H ₆ ^max1 - the minimum and maximum permissible level values, in violation of which the level controller in the buffer tank is switched on,%; E _6i - the mismatch between the value of the level of the return fraction in the buffer tank 6 and its predetermined value,%; S _nшзо , S _nшзi - the initial and predetermined value of the ratio of the costs of the second monomer for the preparation of the charge and charge in the intermediate tank 2; K ₅ , K ₆ , K ₇ - tuning parameters.

 Moreover, the second monomer, necessary for the preparation of the mixture, is supplied in most cases not to the volumeless mixer 1, similarly to other components of the mixture, but to the input of the distillation column 5.

K₉(S_пшi-S_пшзi)Δt , (16) где S_пшi, S_пшзi - соотношение расходов возвратной фракции на приготовление шихты и шихты в промежуточную емкость 2 и его заданное значение;
F_шзi - заданное значение расхода шихты в промежуточную емкость 2, кг/ч; К₈, К₉ - настроечные параметры;
Δt - дискретность формирования управляющего воздействия, ч.The control action of the flow rate controller of the second monomer is formed depending on the value of the ratio of the flow rates of the second monomer to the preparation of the charge and the charge into the intermediate tank 2, the set value of this ratio and the set value of the charge flow into the intermediate tank 2:
F _pzi = S _psci · F _szi + K ₈ (S _psci -S _pscci ) +

K ₉ (S _psci -S _psczi ) Δt, (16) where S _psci , S _pscci - the ratio of the costs of the return fraction for the preparation of the charge and charge in the intermediate tank 2 and its predetermined value;
F _Шзi - set value of the charge flow into the intermediate tank 2, kg / h; K ₈ , K ₉ - tuning parameters;
Δt - discreteness of the formation of the control action,

K₁₁(K_дпi-K $\genfrac{}{}{0ex}{}{\text{оп}}{\text{дп}}$ _з)Δt , (17)
K $\genfrac{}{}{0ex}{}{\text{с}}{\text{т}}$ _мзi= K_тмзо+K₁₂(K_тмi-K $\genfrac{}{}{0ex}{}{\text{оп}}{\text{тм}}$ _з)+

K₁₃(K_тмi-K $\genfrac{}{}{0ex}{}{\text{оп}}{\text{тм}}$ _з) , (18) где К_дпi - текущее значение соотношения концентраций мономеров в шихте;
К_дпз ^оп - заданное оператором-технологом значение соотношения концентраций мономеров в шихте;
К_дпзо - начальное заданное значение соотношения концентраций мономеров в шихте; К_дпзi ^c - скорректированное заданное значение соотношения концентраций мономеров в шихте, К₁₀, К₁₁, К₁₂, К₁₃ - настроечные параметры.The set value of the ratio of the concentrations of monomers in the mixture and the set value of the ratio of the concentrations of the solvent (toluene) and the monomers in the mixture are adjusted depending on the deviations of their current values from those set by the operator-technologist:
K $\genfrac{}{}{0ex}{}{\text{with}}{\text{d}}$ _psi = K _dzzo + K ₁₀ (K _dpi -K $\genfrac{}{}{0ex}{}{\text{op}}{\text{dp}}$ _h ) +

K ₁₁ (K _dpi -K $\genfrac{}{}{0ex}{}{\text{op}}{\text{dp}}$ _h ) Δt, (17)
K $\genfrac{}{}{0ex}{}{\text{with}}{\text{t}}$ _Msi = K _tmzo + K ₁₂ (K _tmi -K $\genfrac{}{}{0ex}{}{\text{op}}{\text{tm}}$ _h ) +

K ₁₃ (K _tmi -K $\genfrac{}{}{0ex}{}{\text{op}}{\text{tm}}$ _h ), (18) where K _dpi is the current value of the ratio of monomer concentrations in the mixture;
To _DPZ ^op - set by the operator-technologist value of the ratio of the concentration of monomers in the mixture;
To _DLO - the initial set value of the ratio of the concentrations of monomers in the mixture; K _dpi ^c - the adjusted set value of the ratio of monomer concentrations in the charge, K ₁₀ , K ₁₁ , K ₁₂ , K ₁₃ - tuning parameters.

(19) где С_пв - концентрация второго мономера в очищенной возвратной фракции (принимается постоянной), масс. доли;
С_х - концентрация примесей в углеводородной шихте, масс. доли.Determine the set value of the ratio of the costs of the purified return fraction for the preparation of the mixture and the mixture into an intermediate tank according to the adjusted set value of the ratio of the concentration of monomers in the mixture, the adjusted set value of the ratio of the concentration of solvent and monomers in the mixture:
S _vshi =

(19) where C _pv is the concentration of the second monomer in the purified return fraction (assumed constant), mass. shares;
C _x is the concentration of impurities in the hydrocarbon charge, mass. share.

^{_ S}вшзi

(20) где С_дд - концентрация первого мономера в его потоке (принимается постоянной), масс. доли;
С_дв - концентрация первого мономера в очищенной возвратной фракции (принимается постоянной), масс. доли.Determine the set value of the ratio of the first monomer consumption for the preparation of the mixture and the mixture into the intermediate tank using the adjusted set value of the ratio of the monomer concentrations in the mixture, the adjusted set value of the ratio of the solvent and monomer concentrations in the mixture, the set value of the ratio of the purified return fraction consumption for the preparation of the mixture and charges in the intermediate tank:
^S dhzi ⁼

^{_ S} high school

(20) where C _dd is the concentration of the first monomer in its stream (assumed constant), mass. shares;
C _dv is the concentration of the first monomer in the purified return fraction (assumed constant), mass. share.

-S_вшзi·C_тв , (21) где С_тв - концентрация растворителя в возвратной фракции (принимается постоянной), масс. доли.Determine the set value of the ratio of the flow rate of the solvent (toluene) for the preparation of the charge and the mixture into the intermediate tank 2 by the adjusted set value of the ratio of the concentrations of the solvent (toluene) and monomers (divinyl and piperylene) in the charge, the set value of the ratio of the costs of the purified return fraction for the preparation of the charge and charge in the intermediate tank 2:
S _tshzi =

-S _vshzi · C _tv , (21) where C _tv is the concentration of solvent in the return fraction (assumed constant), mass. share.

(26)

, (27)
S_тшi=

, (28)
S_вшi=

, (29)
Формируют управляющее воздействие регулятору расхода очищенной возвратной фракции на приготовление шихты в зависимости от значения соотношения расходов очищенной возвратной фракции на приготовление шихты и шихты в промежуточную емкость 2 заданного значения этого соотношения и заданного значения расхода шихты в промежуточную емкость 2:
F_взi= F_вшзi·F_шзi+K₁₄(S_вшi-S_вшзi)+

K₁₅(S_вшi-S_вшзi)Δt , (30) где К₁₄, К₁₅ - настроечные коэффициенты.Formulas for determining the set value of the ratio of the flow rates of the first monomer for the preparation of the charge and the charge in the intermediate tank, the set value for the ratio of the costs of the purified return fraction for the preparation of the mixture and the charge in the intermediate tank, as well as the set value of the ratio of the solvent consumption for the preparation of the mixture and the charge in the intermediate tank 2 obtained by converting and solving a system of equations compiled on the basis of the equations of material balance of the mixture preparation unit This system of equations can be represented as follows:
F + F _{Bi Ti} ˙C _tv = F _shi ˙ C _Ti (22)
F _di ˙ C _dd + F _bi ˙ C _dv = F _wi ˙ C _di , (23)
_Bi F ˙ C _nB = F _shi ˙C _pi, (24)
C _ti + C _di + C _pi + C _xi = 1, (25)

(26)

, (27)
S _tshi =

, (28)
S _lsi =

, (29)
The control action of the flow regulator of the purified return fraction on the preparation of the charge is formed, depending on the value of the ratio of the costs of the purified return fraction on the preparation of the charge and the charge in the intermediate tank 2 of a given value of this ratio and the given value of the charge flow into the intermediate tank 2:
F _vzi = F _vshi · F _szi + K ₁₄ (S _vshi -S _vshzi ) +

K ₁₅ (S _vshi -S _vshzi) Δt, (30) where R _14, R ₁₅ - tuning coefficients.

K₁₇(S_дшi-S_дшзi)Δt , (31) где К₁₆, К₁₇ - настроечные коэффициенты.The control action of the flow rate controller of the first monomer on the preparation of the charge is formed depending on the ratio of the flow rates of the first monomer for the preparation of the charge and the charge in the intermediate tank, the set value of this ratio and the target value of the charge flow into the intermediate tank 2:
F _dzi = F _dszi · F _szi + K ₁₆ (S _dshi -S _dshzi ) +

K ₁₇ (S _dshi -S _dshzi ) Δt, (31) where K ₁₆ , K ₁₇ are tuning factors.

K₁₉(S_тшi-S_тшзi)Δt ,
(32) где К₁₈, К₁₉ - настроечные коэффициенты.Form the control action of the solvent flow regulator on the preparation of the charge, depending on the value of the ratio of the solvent consumption for the preparation of the charge and the charge in the intermediate tank, the set value of this ratio and the target value of the charge in the intermediate tank 2:
F _tzi = F _tszi · F _szi + K ₁₈ (S _tshi -S _tshzi ) +

K ₁₉ (S _tshi -S _tshzi ) Δt,
(32) where K ₁₈ , K ₁₉ are tuning factors.

 An experimental verification of the proposed automatic control method, carried out in the production of low molecular weight divinylpiperylene rubber SKDP-N, confirmed its effectiveness.

At this facility, the volume (capacity) of the intermediate tank 2 for storing the charge is 4 m ³ , and the volume of the buffer tank for storing the return fraction is 10 m ³ . The ratio of the concentration of monomers in the mixture was set at 0.5, the ratio of the concentration of solvent and monomers in the mixture was set at 0.2.

 The concentration of divinyl in the flow of divinyl varied in the range of 92-95%. The content of divinyl, piperylene and toluene in the return fraction varied respectively in the range: 5-10%, 57-73%, 16-30%. The limits of the measurement of expenses: divinyl (0-1552 kg / h), piperylene (0-1403 kg / h), toluene (0-390 kg / h), return fraction (0-2350 kg / h).

 The accuracy of automatic control of the ratio of monomer concentrations in the mixture and the ratio of solvent and monomer concentrations in the mixture increased, respectively, from ± 0.046 to ± 0.021 and from ± 0.057 to ± 0025.

 The results of the experimental verification also confirmed the reduction in the cost of obtaining one ton of rubber SKDP-N by reducing the consumption of divinyl by 4.8 kg and the consumption of piperylene by 9.6 kg to produce one ton of rubber.

 (56) Copyright certificate of the USSR N 979381, cl. C 08 F136 / 08, 1982.

 USSR copyright certificate N 1186622, cl. C 08 F 136/08, 1985.

Claims (1)

 METHOD FOR AUTOMATIC CONTROL OF THE PROCESS OF PREPARING A HYDROCARBON CHARGE IN THE PRODUCTION OF SYNTHETIC RUBBER by automatically controlling the composition of the charge, measuring the consumption of monomer and return fraction for the preparation of the charge, the level of the purified return fraction in the buffer meter, and the flow control monomer and return fraction depending on the level of the purified return fraction in the buffer tank and composition and the mixture, characterized in that it additionally measures the level of the mixture in the intermediate tank, the charge consumption for polymerization, measures and regulates the solvent consumption for the preparation of the mixture, determines the set value of the charge mixture in the intermediate tank, depending on the charge for polymerization and the level of the charge in the intermediate tank , determine the ratio of the concentration of monomer in the mixture and the ratio of the concentrations of solvent and monomers in the mixture, determine the costs of the purified return fraction of the first monomer, the second onomer and solvent for the preparation of the mixture, the ratio of the costs of the purified return fraction for the preparation of the mixture and the mixture in the intermediate tank, the ratio of the costs of the first monomer for the preparation of the mixture and the mixture in the intermediate tank, the ratio of the costs of the second monomer for the preparation of the mixture and the mixture in an intermediate tank and the ratio of solvent the preparation of the charge and charge in an intermediate tank, determine the set value of the ratio of the costs of the second monomer for the preparation of the charge and charge in industrial daily capacity according to the initial value of this ratio and the level of the purified return fraction in the buffer tank, form the control action of the flow control of the second monomer depending on the value of the flow ratio of the second monomer to the preparation of the charge and the charge into the intermediate tank, the set value of this ratio and the set value of the charge in intermediate capacity, adjust the set value of the ratio of the concentration of monomers in the mixture and the set value of the ratio of the concentrations of dissolve For the monomers in the charge, depending on the deviations of their current values from the set by the operator-technologist, determine the set value of the ratio of the costs of the purified return fraction for the preparation of the charge and the charge into the intermediate tank according to the adjusted set value of the ratio of the concentration of monomers in the mixture, the adjusted set value of the ratio of the concentration of solvent and monomers in the charge, determine the set value of the ratio of the costs of the first monomer for the preparation of the charge and charge in the intermediate capacity according to the adjusted set value of the ratio of the concentrations of monomers in the mixture, the adjusted set value of the ratio of the concentrations of solvent and monomers in the mixture, the set value of the ratio of the costs of the purified return fraction for the preparation of the charge and the charge into the intermediate tank, determine the set value of the ratio of the costs of the solvent for the preparation of the charge and charge in intermediate capacity according to the adjusted predetermined value of the ratio of the concentration of solvent and monomers in the mixture , the set value of the ratio of the costs of the purified return fraction for the preparation of the charge and the mixture into the intermediate tank according to the adjusted set value of the ratio of the concentrations of the solvent and the monomers in the mixture, the set value of the ratio of the costs of the purified return fraction for the preparation of the mixture and the charge in the intermediate tank, form the control action of the purified flow controller return fraction for the preparation of the charge, depending on the value of the ratio of the costs of the purified return fraction on the preparation of the charge and charge into the intermediate tank, the set value of this ratio and the set value of the charge flow into the intermediate tank, form the control action of the flow controller of the first monomer on the preparation of the charge, depending on the value of the ratio of the flow rates of the first monomer to the preparation of the charge and charge into the intermediate tank, specified the values of this ratio and the set value of the charge flow into the intermediate tank, and also form the control action of the flow controller I used to prepare the charge depending on the ratio of solvent cost of preparing the charge and the charge in the intermediate tank, the set value of this ratio and the set value of the charge flow in the intermediate tank.

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