CN116081231A - Automatic control method for product abundance in material flow material taking control mode - Google Patents

Abstract

The present invention relates to the technical field of uranium isotope separation, in particular to an automatic control method for product abundance in a material flow taking control mode, comprising the following steps: step 1, setting a control signal; step 1.1 selecting a control time point; step 1.2 calculating the abundance Step 1.3 sets the control signal in sections; Step 2, control signal feedback; Step 3, calculates the adjustment amount of the reclaiming pressure; Step 3.1 calculates the instantaneous abundance target value; Step 3.2 calculates the reclaiming target control pressure; Step 4, The regulator controls the pressure adjustment. The invention is a method for adjusting product abundance with high stability, which reduces the pressure adjustment frequency and adjustment range of the abundance in the container receiving stage, especially in the early stage of receiving, and makes the product receiving process more stable.

Description

A method for automatically controlling product abundance under material flow and material taking control mode

Technical Field

The invention relates to the technical field of uranium isotope separation, and in particular to a product abundance automatic control method under a material flow taking control mode.

Background Art

At present, the production line controls the material flow rate and then controls the product material taking method. The excess amount is fed to the final stage of the concentrate end through reflux, and the final stage material taking ratio is changed to adjust the online instantaneous product abundance (hereinafter referred to as instantaneous abundance) to ensure that the average abundance in the container (hereinafter referred to as bottled abundance) reaches the product quality target. There are two main ways to control the product abundance under this method:

Method 1: In the early stage of material collection, the filling abundance is not controlled, and in the later stage of material collection, the material collection control pressure is adjusted significantly at one time to bring the filling abundance back to the control range. Although this method can achieve the product quality target at the end of container collection, the greater the instantaneous abundance fluctuation during the collection process, the greater the separation work loss in the container.

Method 2: When the bottled abundance exceeds the set control range, the instantaneous abundance is gradually adjusted in steps of 0.01 kPa to bring the bottled abundance back to the center limit. This method will increase the adjustment frequency of the product's instantaneous abundance. As the number of adjustments increases, the separation work loss inside the cascade increases accordingly.

Therefore, it is necessary to design an improved product abundance control method to solve the above-mentioned prior art problems.

Summary of the invention

The present invention proposes an automatic product abundance control method under a material flow material taking control mode, which is used to solve the technical problem in the prior art that the product abundance is adjusted frequently and in a large amplitude during the material taking process, which easily leads to difficulty in stable control of the product abundance.

The technical solution of the present invention:

A method for automatically controlling product abundance under a material flow taking control mode comprises the following steps:

Step 1: Set the control signal;

Step 1.1 Select the control time point;

Step 1.2: Calculate the maximum abundance deviation;

Step 1.3: Set the control signal in sections;

Step 2: Control signal feedback;

Step 3, calculating the adjustment amount of the material taking pressure;

Step 3.1: Calculate the instantaneous abundance target value;

Step 3.2: Calculate the target control pressure for material extraction;

Step 4: Regulator controls pressure adjustment.

The step 1.1 of selecting the control time point includes: according to the actual product production data, counting the average time T ₁ when the bottled abundance enters the control limit as the control signal demarcation point.

The step 1.2 calculates the maximum abundance deviation, including: collecting the instantaneous abundance when the external parameters are stable during a certain operation process, calculating the maximum deviation of the instantaneous abundance of the system, combining the control accuracy of the control pressure _P2 of the control device, and calculating the maximum deviation _μbottle of the bottled abundance based on the relationship between the instantaneous abundance, the control pressure and the bottled abundance.

The step 1.3 of setting the control signal in sections includes:

Select μ ₀ as the product control accuracy, that is, the deviation between the bottled abundance and the target product abundance;

Taking T1 as the time node, the upper and lower control limits C _upper and C _lower of the bottle abundance are set in stages. At this time, the upper control line coordinates of the starting point of material collection are (0, C ₀ +μ _bottle ), and the lower control line coordinates are (0, C ₀ -μ _bottle ); the upper control line coordinates when entering the control range T ₁ are (T ₁ , C _upper ), and the lower control line coordinates when entering the control range are (T ₁ , C _lower ).

At this time, the following bottle abundance control signal calculation equation (1) can be obtained:

Similarly, we can get the following lower limit equation (2):

Where: C _upper —— upper control limit;

C _lower ——lower control limit;

C ₀ —— target product abundance;

_μbottle – maximum deviation of bottle abundance;

μ ₀ ——Daily control accuracy of bottled abundance;

T ₁ ——the shortest time for bottled abundance to enter the control limit range;

——瓶装丰度进入控制线的速率；

- the rate at which bottled abundance enters the control line;

The step 2: control signal feedback includes: collecting the instantaneous abundance at the current moment, calculating the current bottle abundance, the upper and lower limits of the control signal, and comparing them. As long as the bottle abundance does not satisfy C _lower ≤ C _bottle ≤ C _upper , a control adjustment signal is issued.

The step 3.1 of calculating the instantaneous abundance target value includes:

Calculate the target control value of the instantaneous abundance of the product in the later stage according to the current container bottle abundance, bottle loading, target loading of the container and target abundance;

In formula (3):

C _target ——Late instantaneous abundance target control value

_mbottles - the current container's loading capacity

C _Bottle - The bottle abundance of the current container

_m0 ——Target loading volume of product container

C ₀ ——product target abundance.

The step 3.2 of calculating the target control pressure of the material extraction includes:

According to the linear relationship between product feed amount and product abundance, the relative change relationship between product feed amount and product instantaneous abundance is obtained by fitting, as shown in the following formula (4):

δG _P =β ₀ +β ₁ δC _P …………(4)

The product take-off volume can be converted into the control pressure before the orifice plate, i.e. after the regulator, through the orifice plate, as shown in the following formula (5):

G _P = kP ₂ d ² ………………(5)

Where:

d——orifice plate diameter, in cm;

k——orifice coefficient;

P ₂ ——regulator control pressure, unit kPa;

G _P ——product material extraction amount, unit: g/s;

Combined with the orifice calculation formula, the functional relationship between the material extraction pressure _P2 and the instantaneous abundance change is obtained; the target value of the later instantaneous abundance and the current average instantaneous abundance are substituted to calculate the target pressure.

Step 4: Regulator control pressure adjustment, including:

Set the pressure control deviation △P. When the deviation between the online operating pressure and the target pressure exceeds the set value, the regulator valve opening is slightly opened or slightly closed to adjust the regulator pressure value to the target value. When the online operating pressure is lower than the target pressure, the regulator valve opening is slightly opened; when the online operating pressure is higher than the target pressure, the regulator valve opening is slightly closed.

Beneficial effects of the present invention:

The present invention is applicable to intelligent control of product abundance under material flow control and material taking in the field of centrifugal separation. The present invention is a product abundance adjustment method with high stability, which reduces the pressure adjustment frequency and adjustment range of abundance in the container receiving stage, especially in the early stage of receiving, and the product receiving process is more stable. The average standard deviation of container bottling abundance is generally less than 0.00004.

DETAILED DESCRIPTION

The following is a detailed description of a method for automatically controlling product abundance under a material flow taking control mode of the present invention in conjunction with an embodiment.

A method for automatically controlling product abundance under a material flow taking control mode comprises the following steps:

Step 1: Set the control signal;

Step 1.1 selects the control time point, including: according to the actual product production data, the average time T ₁ at which the bottled abundance enters the control limit is counted as the control signal demarcation point.

Step 1.2 calculates the maximum abundance deviation, including: collecting the instantaneous abundance when the external parameters are stable during a certain operation process, calculating the maximum deviation of the system's instantaneous abundance, combining the control accuracy of the control pressure _P2 of the control equipment, and calculating the maximum deviation of the bottled abundance _μbottle based on the relationship between the instantaneous abundance, the control pressure and the bottled abundance.

Step 1.3 sets the control signal in sections, including:

Select μ ₀ as the product control accuracy, that is, the deviation between the bottled abundance and the target product abundance;

Taking T1 as the time node, the upper and lower control limits C _upper and C _lower of the bottle abundance are set in stages. At this time, the upper control line coordinates of the starting point of material collection are (0, C ₀ +μ _bottle ), and the lower control line coordinates are (0, C ₀ -μ _bottle ); the upper control line coordinates when entering the control range T ₁ are (T ₁ , C _upper ), and the lower control line coordinates when entering the control range are (T ₁ , C _lower ).

At this time, the following bottle abundance control signal calculation equation (1) can be obtained:

Similarly, we can get the following lower limit equation (2):

Where:

C _upper —— upper control limit;

C _lower ——lower control limit;

C ₀ —— target product abundance;

_μbottle – maximum deviation of bottle abundance;

μ ₀ ——Daily control accuracy of bottled abundance;

T ₁ ——the shortest time for bottled abundance to enter the control limit range;

——瓶装丰度进入控制线的速率；

- the rate at which bottled abundance enters the control line;

Step 2, control signal feedback; including: collecting the instantaneous abundance at the current moment, calculating the current bottled abundance, the upper and lower limits of the control signal, and comparing them. As long as the bottled abundance does not satisfy C _lower ≤ C _bottle ≤ C _upper , a control adjustment signal is issued.

Step 3, calculating the adjustment amount of the material taking pressure;

Step 3.1 Calculate the instantaneous abundance target value, including:

Calculate the target control value of the instantaneous abundance of the product in the later stage according to the current container bottle abundance, bottle loading, target loading of the container and target abundance;

In formula (3):

C _target ——Late instantaneous abundance target control value

_mbottles - the current container's loading capacity

C _Bottle - The bottle abundance of the current container

_m0 ——Target loading volume of product container

C ₀ ——product target abundance.

Step 3.2 calculates the target control pressure for material extraction, including:

According to the linear relationship between product feed amount and product abundance, the relative change relationship between product feed amount and product instantaneous abundance is obtained by fitting, as shown in the following formula (4):

δG _P =β ₀ +β ₁ δC _P …………(4)

The product take-off volume can be converted into the control pressure before the orifice plate, i.e. after the regulator, through the orifice plate, as shown in the following formula (5):

G _P = kP ₂ d ² ………………(5)

Where:

d——orifice plate diameter, in cm;

k——orifice coefficient;

P ₂ ——regulator control pressure, unit kPa;

G _P ——product material extraction amount, unit: g/s;

Combined with the orifice calculation formula, the functional relationship between the material extraction pressure _P2 and the instantaneous abundance change is obtained; the target value of the later instantaneous abundance and the current average instantaneous abundance are substituted to calculate the target pressure.

Step 4: The regulator controls the pressure adjustment, including:

Set the pressure control deviation △P. When the deviation between the online operating pressure and the target pressure exceeds the set value, the regulator valve opening is slightly opened or slightly closed to adjust the regulator pressure value to the target value. When the online operating pressure is lower than the target pressure, the regulator valve opening is slightly opened; when the online operating pressure is higher than the target pressure, the regulator valve opening is slightly closed.

Example

Example: Taking the abundance adjustment of a centrifugal cascade product as an example, the receiving container starts receiving materials at 22:36 on March 14, 2022. The target product abundance of the container is 4.0%, and the target loading volume of the container is 6000 kg.

Step 1: Set up the control feedback signal

Step 1.1 Select control time points

According to actual operation statistics, taking into account the non-steady-state process of scheme conversion, it generally takes 10 measurement points (including 1 non-steady-state process measurement once every 2 hours and 1 steady-state process measurement once every 4 hours) for about 30 hours for the bottled abundance of the production line to enter the control range. Therefore, T1=30h is used, and a segmented control signal is established with 30h as the boundary.

Step 1.2 Calculate the maximum abundance deviation

In the actual production process of a 4.65% product, when the external parameters and auxiliary parameters fluctuated within the range, 218 instantaneous data were collected under the same control pressure P _2. By statistically analyzing the distribution of this group of data, the maximum deviation of the instantaneous abundance was about 0.011%. The regulating device used on the product extraction pipeline of the current production line is a regulator, and its pressure control accuracy is σ _P = 0.01kPa.

Usually, when calculating the product filling abundance, the product collection process is divided into several collection processes at the same time interval, so as to obtain the calculation formula of the filling abundance:

Where:

P _i ——regulator control pressure in the i-th time interval;

Δt——time interval, the value is usually 4h;

——时间间隔内平均瞬时丰度；

——mean instantaneous abundance within a time interval;

At this time, the absolute deviation of bottled abundance is:

in:

The calculated maximum deviation of bottled abundance is _μbottle =0.015%.

Step 1.3 Set up equations in sections

Select product control accuracy μ ₀ = 0.002%, μ _bottle = 0.015%. At this time, the upper limit control line coordinates of the product at the starting point of material collection are (0, 4.0% + 0.015%), and the lower limit control line coordinates are (0, 4.0% - 0.015%); when entering the control range at time T ₁ , the upper limit control line coordinates are (30, Cupper), and the lower limit control line coordinates are (30, Clower) when entering the control range.

At this time, the upper limit equation of the bottle abundance control line can be obtained

Lower limit equation

Step 2: Control signal feedback

At 9:00 on March 16, 2022, the current container filling volume is 1077kg, and the control pressure is 4.94kPa. The filling abundance is calculated to be 3.9942% at this time. The container has been running for 34.4 hours, exceeding 30 hours. The control signal values C _upper = 4.002% and C _lower = 3.998%. The filling abundance is less than C _lower, which exceeds the control limit, and a control signal is issued.

Step 3: Calculation of material reclaim pressure adjustment

Step 3.1 Calculation of instantaneous abundance control target value

According to formula (1), the instantaneous abundance control target value can be calculated as

Step 3.2 Calculate the target control pressure for material extraction

The relative change of product abundance is linearly related to the relative change of product feed quantity. The data is fitted to obtain a univariate linear regression model of the relative change of product abundance and feed quantity.

δG _P =-2.00×10 ^-5 -1.224δC _P

Through the orifice calculation formula, ignoring the minimum term, the product feed volume is converted into the regulator control pressure, and the functional relationship between the change of product instantaneous abundance and the control pressure can be obtained:

Where:

P2 _target —— product material taking control pressure target value;

P ₂ ——Current product taking control pressure;

C _target —— product instantaneous abundance control target value;

C _{instantaneous} - average instantaneous abundance of the current product;

Substituting the instantaneous abundance target value of 4.0013% and the current average instantaneous abundance of 3.9935%, the target pressure of 4.928 kPa is calculated.

Step 4: Regulator Control Pressure Adjustment

The set deviation value △P is 0.007kPa. At this time, the difference between the target control pressure and the online pressure is -0.012kPa, which exceeds the set deviation value and is lower than the current online pressure. The online operating pressure is greater than the target pressure. Therefore, the regulator valve is slightly closed and the regulator control pressure is adjusted to 4.93kPa.

The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present invention.

Claims (8)

1. The automatic control method for the product abundance in the material flow material taking control mode is characterized by comprising the following steps:

step 1, setting a control signal;

step 1.1, selecting a control time point;

step 1.2, calculating the maximum deviation of abundance;

step 1.3, setting control signals in a segmented mode;

step 2, control signal feedback;

step 3, calculating the material taking pressure adjustment quantity;

step 3.1, calculating an instantaneous abundance target value;

step 3.2, calculating a material taking target control pressure;

and 4, controlling pressure adjustment by a regulator.

2. The method for automatically controlling the abundance of a product in a material taking control mode according to claim 1, wherein the method comprises the following steps: the step 1.1 selects a control time point, including: according to actual product production data, counting average time T of entering control limit value of bottled abundance ₁ As a control signal demarcation point.

3. The method for automatically controlling the abundance of a product in a material taking control mode according to claim 2, wherein the method comprises the following steps: the step 1.2 calculates the maximum deviation of abundance, including: collecting instantaneous abundance when external parameters are stable in a certain operation process, calculating the maximum deviation of the instantaneous abundance of a system, and combining control equipment to controlPressure P ₂ Calculating the maximum deviation mu of the bottled abundance according to the relation among the instantaneous abundance, the control pressure and the bottled abundance _{Bottle (B)} 。

4. A method for automatically controlling product abundance in a flow take-off control according to claim 3, wherein: the step 1.3 of setting the control signal in a segmented manner comprises the following steps:

select μ ₀ The product control precision is the deviation of the bottle abundance and the target product abundance;

taking T1 as a time node, and setting a control upper limit C of bottled abundance in a segmented manner _upper And lower limit C _lower At this time, the upper limit control line coordinates (0, C) ₀ +μ _{Bottle (B)} ) Lower limit control line coordinates (0, C ₀ -μ _{Bottle (B)} ) The method comprises the steps of carrying out a first treatment on the surface of the Enter control range T ₁ Time upper limit control line coordinates (T ₁ ,C _upper ) Lower limit control line coordinates (T ₁ ,C _lower )。

At this time, the following calculation equation (1) of the bottled abundance control signal can be obtained

Lower limit equation (2) of the same theory

Wherein: c (C) _uppr -controlling the upper limit value;

C _lower -control lower limit value;

C ₀ -target product abundance;

μ _{bottle (B)} -maximum deviation of bottled abundance;

μ ₀ -daily control accuracy of bottled abundance;

T ₁ bottled abundance access controlThe shortest time of the limit range;

-the rate at which the bottled abundance enters the control line. />

5. The method for automatically controlling the abundance of a material in a material taking control mode according to claim 4, wherein the method comprises the following steps: the step 2: control signal feedback, comprising: collecting instantaneous abundance at the current moment, calculating the current bottled abundance and upper and lower limit values of control signals, and comparing, so long as the bottled abundance does not meet C _lower ≤C _{Bottle (B)} ≤C _upper And sending out a control adjustment signal.

6. The method for automatically controlling the abundance of a material in a feeding and withdrawing control mode according to claim 5, wherein: the step 3.1 calculates the target value of instantaneous abundance, which comprises the following steps:

calculating a target control value of the instantaneous abundance in the later period of the product according to the current container bottle abundance, the bottle loading capacity, the target container loading capacity and the target abundance;

in the formula (3):

C _target -post-transient abundance target control value

m _{Bottle (B)} Current container load

C _{Bottle (B)} -bottled abundance of the current container

m ₀ Target load of product container settings

C ₀ -product target abundance.

7. The method for automatically controlling the abundance of a material in a feeding and withdrawing control mode according to claim 6, wherein: step 3.2 calculates a take-off target control pressure, comprising:

fitting to obtain a relative change relation between the product taking amount and the instantaneous abundance of the product according to a linear relation between the product taking amount and the product abundance, wherein the relative change relation is represented by the following formula (4):

δG _P ＝β ₀ +β ₁ δC _P …………(4)

the product taking amount can be converted into a pore plate through the pore plate, namely the pressure is controlled after the regulator, and the following formula (5) is adopted:

G _P ＝kP ₂ d ² ………………(5)

wherein:

d, pore diameter of pore plate, unit cm;

k-orifice plate coefficient;

P ₂ -regulator control pressure, unit kPa;

G _P -product take-off, in g/s;

combining with a pore plate calculation formula to obtain a material taking pressure P ₂ Functional relationship with instantaneous abundance changes; substituting the target value of the later-period instantaneous abundance and the current average instantaneous abundance, and calculating to obtain the target pressure.

8. The method for automatically controlling the abundance of a material in a feeding and withdrawing control mode according to claim 7, wherein: step 4: the regulator controls pressure regulation, including:

setting a pressure control deviation delta P, and when the deviation between the online running pressure and the target pressure exceeds a set value, adjusting the pressure value of the regulator to the target value through slightly opening and slightly closing the valve opening of the regulator; and slightly opening the regulator valve opening when the online operation pressure is smaller than the target pressure, and slightly closing the regulator valve opening when the online operation pressure is larger than the target pressure.