RU2084946C1 - Method for automatic control of mixing raw material with batched component - Google Patents

Abstract

FIELD: oil refining, chemical, and other industries. SUBSTANCE: method for automatic control of mixing loose material (batched component) and liquid (raw material) involves control of batched component concentration in mixture by varying batched component solution feed; controlling action is formed proceeding from desired concentration of batched component solution and concentration of batched component in mixture, as well as metered flow rates of batched component solution and raw material. EFFECT: enlarged functional capabilities. 1 dwg

Description

 The invention relates to processes for mixing bulk materials (dosed component) and liquid (raw materials) and can be used in the refining, chemical and other industries.

A known method of automatically controlling the process of mixing liquids, providing for the regulation of the concentration of the mixture by changing the flow of one of the source liquids [1]
Closest to the claimed solution is a method for automatically controlling the concentration, which consists in regulating the concentration of the dosed component in the mixture by changing the flow of its solution [2]
The disadvantage of this method is that the accuracy of the concentration control is determined mainly by the metrological characteristics of the concentration sensor, which, in many cases, worse than the characteristics of the flow sensors. Therefore, in the case of frequent changes in raw material costs, the dynamics of the regulatory process may not meet the requirements and the quality of regulation will be low.

 In addition, the use of an analyzer that measures the composition of the mixture leads to a delay in regulation by the amount of transport delay, the value of which depends on the distance between the flowmeters and the analyzer and the speed of the flows.

 The objective of the invention is to increase the accuracy of concentration control in the case of frequent fluctuations in the consumption of raw materials.

 The drawing shows a block diagram of a device for implementing the proposed method.

It contains a container 1 for storing the initial solution of the dosed component, a component concentration adjuster 2 in the initial solution C _p , connected by the output through the computing unit 3 to the first input of the multiplication unit 4, the second input of which is connected to the flow sensor 5 of the solution V _p , and the output to the input regulator 6; a setter 7 of the concentration of the dosage component in the mixture C _d.k. connected to the inputs of the computing unit 3 and the multiplication unit 8, the second input of which is connected to the flow sensor 9 of the raw material V _c , and the output to the second input of the controller 6, connected by the output to the actuator 10 on the solution supply line of the dosed component.

 The device operates as follows.

 In the initial position, the actuator 10 is closed, the solution of the dosed component and the raw materials are not received. Before starting the preparation, the concentration of the dosed component in the initial solution is established (set) on the dial 2, and on the dial 7 the concentration of the dosed component in the mixture after raw materials with the solution of the dosed component, i.e. preset concentration. In this case, the raw material does not contain a metered component.

The output signals of the setter 7 and setter 2 are converted in the computing unit 3 in accordance with the possibility of V _{output 3} C _p - (1-C _p ): C _d.k. , and the output signal of the block goes to the input of the multiplication block 4. Since the second outputs of blocks 4 and 8 are zero (the dosed component solution and raw materials are not supplied), the output signals of these blocks and controller 6 remain zero, the actuator 10 does not change its position ( closed).

 When supplying raw materials for the preparation of the solution, a non-zero signal appears at the second input of the multiplication unit 8, therefore, a non-zero signal arrives at one input of the regulator 6, and a zero signal at the second input.

 In the controller 6, an output signal is formed according to the law of PI control.

 The output signal of the controller 6 increases, the actuator 10 begins to open, the solution of the dosed component enters the feedstock. A nonzero signal arrives at the second input of the controller, controller 7 controls the actuator 10 depending on the size of the output signal mismatch of multiplication units 4 and 8, the transition process ends, and a constant flow rate of the dosed component solution is established.

 A change in the concentration of the component in the mixture or a change in the concentration of the solution of the dosed component is carried out by setting new concentrations on the adjusters 7 and 2. As a result, the output signals of blocks 4 and 8 will change, the output signal of the controller 6 will begin to change the position of the actuator 10, and after the end of the transition process, a new value of the flow rate of the solution of the dosed component will be established.

 In accordance with the invention, the use of concentration sensors is excluded, therefore, the dynamic properties of the control system are improved. This reduces the time of the transition process and the deviation of the concentration of the dosed component in the mixture from the set one.

Claims (1)

A method for automatically controlling the process of mixing raw materials and the dosed component, including measuring the flow rate V _{from the} raw materials and controlling the flow rate of the solution of the dosed component, characterized in that they generate a signal proportional to the set concentration value C _{p of the} solution of the dosed component, measure the flow rate V _{r of the} solution of the dosed component proportional to a given value the concentration C _{d. a} metering component in the mixture, calculated signal proportional to the current value of V _{d flow. to the} dosed component in accordance with the dependence
V _{d . to} V _p [C _p (1 C _p ) • C _{d . to} ]
calculating a signal proportional to a predetermined value _{of a} flow rate V _{d. d . to the} dosed component in accordance with the dependence
V _{s and d. d . to} V _s • C _{d . to}
and the regulatory action is formed in accordance with the difference of the signals calculated above.