A method for evaluating the control loop of a distillation column

Abstract

This invention proposes a method for evaluating the control loop of a distillation column, belonging to the field of operational loop evaluation for chemical distillation columns. The method includes the following steps: selecting a distillation column control loop; calculating the automatic start-up rate of the control loop; calculating the mean and variance of the controlled variable in manual mode; calculating the mean, variance, and integral of the absolute value of the error of the controlled variable in automatic mode; calculating the viscosity of the actuator in manual mode; calculating the viscosity of the actuator in automatic mode; calculating the mean score and variance score of the control loop in manual mode; calculating the mean score, variance score, and integral of the error of the control loop in automatic mode; and calculating the automatic start-up rate, evaluation score in manual mode, and evaluation score in automatic mode. This method can quantitatively analyze the control quality of a distillation column control loop and has strong application value.

Description

Technical Field

[0001] This invention relates to the field of evaluation of operating loops in chemical distillation columns, and more particularly to a method for evaluating control loops in distillation columns. Background Technology

[0002] As a core piece of equipment for separating mixtures in the chemical, petroleum, and pharmaceutical industries, the level of operation of distillation columns directly affects product quality, energy consumption, and production efficiency.

[0003] Currently, there is limited research on methods for evaluating the operating status of distillation columns. Some research exists on loop evaluation in power systems, such as methods for evaluating the error status of secondary loops (CN202411472868.1), evaluating the performance of temperature control loops (CN202311100060.6), evaluating the performance of PID control loops (CN202311382820.7), and evaluating the performance of control loops in distributed control systems (CN202210859982.4). These loop evaluation methods primarily focus on the control performance under automatic operation, neglecting the evaluation of manual operation in distillation column systems. Furthermore, their implementation is difficult. This invention proposes a distillation column control loop evaluation method that can calculate the automatic operation rate of the distillation column loop and normalize the control quality scores under both automatic and manual operation. It calculates the evaluation scores under both manual and automatic operation conditions, featuring clear calculation formulas, quantitative measurement, and rapid implementation, making it highly valuable for application. Summary of the Invention

[0004] This invention proposes a method for evaluating the control loop of a distillation column, belonging to the field of operational loop evaluation for chemical distillation columns. The method includes the following steps: selecting a distillation column control loop; calculating the automatic start-up rate of the control loop; calculating the mean and variance of the controlled variable in manual mode; calculating the mean, variance, and integral of the absolute value of the error of the controlled variable in automatic mode; calculating the viscosity of the actuator in manual mode; calculating the viscosity of the actuator in automatic mode; calculating the mean score and variance score of the control loop in manual mode; calculating the mean score, variance score, and integral of the error of the control loop in automatic mode; and calculating the automatic start-up rate, the evaluation score of the control loop in manual mode, and the evaluation score of the control loop in automatic mode. This method can quantitatively analyze the control quality of a distillation column control loop and has strong practical application value.

[0005] A method for evaluating the control loop of a distillation column, characterized by comprising the following steps:

[0006] Step 1: Select a control loop of the distillation column system and perform sampling according to a certain sampling period. collection n The controlled variable PV, the setpoint SP, the actuator command value MV, and the actuator feedback value MV of this control loop are: f Automatic activation status Au, For investment, This indicates that the automatic system has not been activated.

[0007] Step 2: Calculate the automatic activation rate of the control loop. :

[0008] Step 3: Calculate the mean value of the controlled variable in the control loop under manual mode. :

[0009] Step 4: Calculate the variance of the controlled variable fluctuation in the control loop under manual mode. :

[0010] Step 5: Calculate the mean value of the controlled variable in the control loop under automatic mode. ;

[0011] Step 6: Calculate the variance of the controlled variable fluctuation in the control loop under automatic mode. ;

[0012] Step 7: Calculate the integral of the absolute value of the error of the controlled variable in the automatic state. ;

[0013] Step 8: Calculate the viscosity of the actuator in the control loop under manual mode. ;

[0014] Step 9: Calculate the viscosity of the actuator in the control loop under automatic mode. ;

[0015] Step 10: Based on the expected mean value of the controlled variable in the control loop under manual mode. Calculate the mean score of the control loop in manual mode. ;

[0016] Step 11: Based on the expected variance of the controlled variable under manual conditions Calculate the fluctuation variance score of the control loop in manual mode. ;

[0017] Step 12: Based on the expected mean value of the controlled variable in the control loop under automatic state. Calculate the mean score of the control loop in automatic mode. ;

[0018] Step 13: Based on the expected variance of the controlled variable under automatic conditions Calculate the fluctuation variance score of the control loop in automatic mode. ;

[0019] Step fourteen: Integrate the absolute value of the expected error of the controlled variable under automatic state. Calculate the integral score of the absolute value of the error of the control loop in automatic mode. ;

[0020] Step 15, based on the results obtained in Step 8 Step 10 and the result obtained in step 11 The evaluation score of the control loop under manual operation is obtained. ;

[0021] Step sixteen, based on the results obtained in step nine Step Twelve Step Thirteen and the result obtained in step fourteen The evaluation score of the control loop under automatic operation is obtained. ;

[0022] Step 17: Obtain the automatic engagement rate of the control loop. Evaluation score of the control loop in manual operation mode Evaluation score of the control loop in automatic operation mode. .

[0023] Furthermore, in step two, the automatic activation rate of the control loop is calculated using the following formula. :

[0024] (1);

[0025] in i Indicates the first i At each data collection moment, Indicates the first i The collected automatic deployment status data;

[0026] In step three, the mean value of the controlled variable in the control loop under manual mode is calculated using the following formula. :

[0027] (2);

[0028] in j Indicates the first j At each data collection moment, This indicates the automatic activation status statistics, i.e. From time to time , From time to time ; express j The values ​​of the controlled variables, and From time to time , From time to time .

[0029] Furthermore, in step four, the variance of the controlled variable fluctuation in the control loop under manual mode is calculated using the following formula. :

[0030] (3);

[0031] Formula (3) means that... Calculations are performed when the time is right, otherwise the calculation is skipped. j The formula (3) is used to calculate the data at each acquisition time.

[0032] In step five, the mean value of the controlled variable in the control loop under automatic state is calculated using the following formula. :

[0033] (4);

[0034] in p Indicates the first p At each data collection moment, This indicates the automatic activation status statistics, i.e. From time to time , From time to time ; express p The values ​​of the controlled variables, and From time to time , From time to time .

[0035] Furthermore, in step six, the variance of the controlled variable fluctuation in the control loop under automatic state is calculated using the following formula. :

[0036] (5);

[0037] in Formula (5) means that... Calculations are performed when the time is right, otherwise the calculation is skipped. p The formula (5) is used to calculate the data at each acquisition time.

[0038] In step seven, the integral of the absolute value of the error of the controlled variable in the automatic state is calculated using the following formula. :

[0039] (6);

[0040] in x Indicates the first x At each data collection moment, Formula (6) means that... Calculations are performed when the time is right, otherwise the calculation is skipped. x The formula (6) is used to calculate the data at each acquisition time.

[0041] Furthermore, in step eight, the viscosity of the actuator in the control loop under manual mode is calculated using the following formula. :

[0042] (7);

[0043] in z Indicates the first z At each data collection moment, When the formula (7) is expressed, it means that the formula (7) is in Calculations are performed when the time is right, otherwise the calculation is skipped. z The formula (7) is used to calculate the data at each acquisition time.

[0044] In step nine, the viscosity of the actuator in the control loop under automatic state is calculated using the following formula. :

[0045] (8);

[0046] in y Indicates the first y At each data collection moment, When the formula (8) is expressed, it means that the formula (8) is in Calculations are performed when the time is right, otherwise the calculation is skipped. y The formula (8) is used to calculate the data at each acquisition time.

[0047] Furthermore, in step ten, based on the expected mean value of the controlled variable of the control loop in manual mode... Calculate the mean score of the control loop in manual mode. :

[0048] (9);

[0049] In step eleven, the fluctuation variance score of the control loop in manual mode. :

[0050] (10).

[0051] 7. In step twelfth, the average score of the control loop in automatic mode is calculated. :

[0052] (11);

[0053] In step thirteen, the fluctuation variance score of the control loop in automatic mode is calculated. :

[0054] (12).

[0055] Furthermore, in step fourteen, the integral score of the absolute value of the error of the control loop in automatic mode is calculated. :

[0056] (13).

[0057] Furthermore, in step fifteen, the evaluation score of the control loop in manual operation mode. :

[0058] (14)

[0059] in , and Weighting systems typically include... ,and , , .

[0060] Furthermore, in step sixteen, the evaluation score of the control loop in its automatic operation state is... :

[0061] (15)

[0062] in , , and For weighted systems, there are generally... ,and , , and .

[0063] Step 17: Obtain the automatic engagement rate of the control loop. Evaluation score of the control loop in manual operation mode Evaluation score of the control loop in automatic operation mode. .

[0064] Compared with existing technologies, the beneficial effects of this invention are as follows: Addressing the limited research on evaluation methods for the operating status of distillation columns, this technical solution proposes a method for evaluating the control loop of a distillation column. This method enables the calculation of the automatic start-up rate of the distillation column loop and the normalized scoring of control quality under automatic and manual states. It calculates evaluation scores for both manual and automatic operation states. This technical solution considers the system operating quality under both automatic and manual states. Furthermore, this technical solution allows for quantitative, visual, and multi-dimensional analysis of the distillation column system, guiding control optimization and evaluating control quality before and after optimization, thus possessing significant value. Attached Figure Description

[0065] Figure 1 This invention provides a method for evaluating the control loop of a distillation column. Detailed Implementation

[0066] A method for evaluating the control loop of a distillation column, the process is as follows: Figure 1 As shown, the feature is that it includes the following steps:

[0067] A method for evaluating the control loop of a distillation column, characterized by comprising the following steps:

[0068] 101: Select a control loop of the distillation column system and, according to a certain sampling period... collection n The controlled variable PV, the setpoint SP, the actuator command value MV, and the actuator feedback value MV of this control loop are: f Automatic activation status Au, For investment, This indicates that automatic operation is not activated. In this embodiment, the light component content loop in the top product of the distillation column system is selected. The controlled variable is the light component content in the top product of the distillation column system. The set value of the controlled variable is the set value of the light component content in the top product of the distillation column system, the actuator command value is the reflux flow rate, and the actuator feedback value is the actual value of the reflux flow rate. Second, ;

[0069] 102: Calculate the automatic activation rate of this control loop using the following formula. :

[0070] (1)

[0071] in i Indicates the first i At each data collection moment, Indicates the first i The collected automatic deployment status data; in this embodiment ;

[0072] 103: Calculate the mean value of the controlled variable in the control loop under manual mode using the following formula. :

[0073] (2)

[0074] in j Indicates the first j At each data collection moment, This indicates the automatic activation status statistics, i.e. From time to time , From time to time ; express j The values ​​of the controlled variables, and From time to time , From time to time In this embodiment, the average light component content in the top product of the distillation column system under manual operation is... ;

[0075] 104: Calculate the variance of the controlled variable fluctuation in the manual mode using the following formula. :

[0076] (3)

[0077] Formula (3) means that... Calculations are performed when the time is right, otherwise the calculation is skipped. j The formula (3) is used to calculate the variance of light component content fluctuation in the top product of the distillation column system in this embodiment under manual operation. ;

[0078] 105: Calculate the mean value of the controlled variable in the control loop under automatic state using the following formula. :

[0079] (4)

[0080] in p Indicates the first p At each data collection moment, This indicates the automatic activation status statistics, i.e. From time to time , From time to time ; express p The values ​​of the controlled variables, and From time to time , From time to time In this embodiment, the average light component content in the top product of the distillation column system under automatic loop operation is... ;

[0081] 106: Calculate the variance of the controlled variable fluctuation in the automatic state using the following formula. :

[0082] (5)

[0083] in Formula (5) means that... Calculations are performed when the time is right, otherwise the calculation is skipped. p The formula (5) is used to calculate the variance of light component content fluctuation in the top product of the distillation column system in this embodiment under automatic loop conditions. ;

[0084] 107: Calculate the integral of the absolute value of the error of the controlled variable in the automatic state using the following formula. :

[0085] (6)

[0086] in x Indicates the first x At each data collection moment, Formula (6) means that... Calculations are performed when the time is right, otherwise the calculation is skipped. x The formula (6) is used to calculate the content of light components in the top product of the distillation column system in this embodiment under automatic loop conditions. ;

[0087] 108: Calculate the viscosity of the actuator in manual mode using the following formula. :

[0088] (7)

[0089] in z Indicates the first z At each data collection moment, When the formula (7) is expressed, it means that the formula (7) is in Calculations are performed when the time is right, otherwise the calculation is skipped. z The formula (7) is used to calculate the content of light components in the top product of the distillation column system in this embodiment; the viscosity of the actuator in the manual state of the loop. ;

[0090] 109: Calculate the viscosity of the actuator in the control loop under automatic conditions using the following formula. :

[0091] (8)

[0092] in y Indicates the first y At each data collection moment, When the formula (8) is expressed, it means that the formula (8) is in Calculations are performed when the time is right, otherwise the calculation is skipped. y The formula (8) is used to calculate the content of light components in the top product of the distillation column system in this embodiment; the viscosity of the actuator in the automatic state of the loop is calculated using the formula (8) at each acquisition time. ;

[0093] 110: Expected mean value of the controlled variable in the control loop under manual mode. Calculate the mean score of the control loop in manual mode. :

[0094] (9)

[0095] In this embodiment, The content of light components in the top product of the distillation column system is worth noting under manual operation. ;

[0096] 111: Expected Variance of Controlled Variables under Manual Operation Calculate the fluctuation variance score of the control loop in manual mode. :

[0097] (10)

[0098] In this embodiment, The variance score of light component content in the top product of the distillation column system under manual operation. ;

[0099] 112: The expected mean value of the controlled variable in the control loop under automatic conditions. Calculate the mean score of the control loop in automatic mode. :

[0100] (11)

[0101] In this embodiment, The content of light components in the top product of the distillation column system is averaged under automatic loop conditions. ;

[0102] 113: Expected Variance of Controlled Variables under Automatic Conditions Calculate the fluctuation variance score of the control loop in automatic mode. :

[0103] (12)

[0104] In this embodiment, The variance score of the light component content in the top product of the distillation column system under automatic loop conditions. ;

[0105] 114: Integral of the absolute value of the expected error of the controlled variable under automatic conditions Calculate the integral score of the absolute value of the error of the control loop in automatic mode. :

[0106] (13)

[0107] In this embodiment, The integral of the absolute value of the error in the automatic operation of the distillation column system for the content of light components in the top product. ;

[0108] 115: Based on step 108 The result obtained in step 110 And obtained in step 111 The evaluation score of the control loop under manual operation is obtained. :

[0109] (14)

[0110] in , and Weighting systems typically include... ,and , , In this embodiment The evaluation score for the light component content in the top product of the distillation column system under manual operation was obtained. ;

[0111] 116: Based on step 109 The result obtained in step 112 The result obtained in step 113 And obtained in step 114 The evaluation score of the control loop under automatic operation is obtained. :

[0112] (15)

[0113] in , , and For weighted systems, there are generally... ,and , , and In this embodiment The evaluation score for the automatic operation of the distillation column system under the condition of obtaining the light component content in the top product of the column was: ;

[0114] 117: Obtain the automatic engagement rate of this control loop. Evaluation score of the control loop in manual operation mode Evaluation score of the control loop in automatic operation mode. In this embodiment, the automatic start-up rate of the loop containing light components in the top product of the distillation column system is as follows: Evaluation score of the control loop in manual operation mode Evaluation score of the control loop in automatic operation mode. .

Claims

1. A method for evaluating the control loop of a distillation column, characterized in that, Includes the following steps: Step 1: Select a control loop of the distillation column system and collect n data points for that control loop at a certain sampling period Δh: the controlled variable PV, the setpoint SP of the controlled variable, the actuator command value MV, and the actuator feedback value MV. f Step 1: Automatic activation state Au, where Au = 1 indicates activation and Au = 0 indicates automatic activation not in operation; Step 2: Calculate the automatic activation rate η of this control loop; Steps 3 and 4: Calculate the mean value μ of the controlled variable of this control loop in manual mode, respectively. ma and the variance of the controlled variable Steps five through seven: Calculate the mean value μ of the controlled variable in the control loop under automatic mode. au Fluctuation and variance Integral of absolute error (IAE) au Step 8: Calculate the viscosity l of the actuator in the control loop under manual mode. ma Steps nine and ten: Calculate the viscosity l of the actuator in the control loop under automatic conditions. au The average value is worth dividing Step 11: Calculate the fluctuation variance score of the control loop in manual mode. Steps twelve through fourteen: Average score of the control loop in automatic mode. Fluctuation variance score Score of the integral of the absolute value of the error Step 15: Obtain the evaluation score c for the control loop in manual operation mode. ma Step sixteen: Obtain the evaluation score c of the control loop under automatic operation. au Step 17: Obtain the automatic activation rate η of the control loop and the evaluation score c of the control loop in manual operation mode. ma The evaluation score c of the control loop in automatic operation mode. au ; In step eight, the viscosity l of the actuator in the control loop under manual mode is calculated using the following formula. ma : Where z represents the z-th data collection time, Au z =0 indicates that formula (7) is in Au z When = 0, the calculation is performed; otherwise, the calculation of formula (7) at the z-th acquisition time is skipped. In step nine, the viscosity l of the actuator in the control loop under automatic state is calculated using the following formula. au : Where y represents the y-th data collection time, Au y =1 indicates that formula (8) is in Au y When y = 1, the calculation is performed; otherwise, the calculation of formula (8) at the y-th acquisition time is skipped.

2. The method for evaluating a distillation column control loop according to claim 1, characterized in that: In step two, the automatic activation rate η of the control loop is calculated using the following formula: Where i represents the i-th data collection time, Au i This represents the automatic input status data collected for the i-th time. In step three, the mean value μ of the controlled variable of the control loop in manual mode is calculated using the following formula. ma : Where j represents the j-th data collection time, and m represents the automatic activation status statistics, i.e., Au j When = 0, m = 1, Au j When PV = 1, m = 0; jm Let Au represent the values ​​of j controlled variables, and Au j =0 when there is PV jm =PV j Au j =1 when there is PV jm =0.

3. The method for evaluating a distillation column control loop according to claim 2, characterized in that: In step four, the variance of the controlled variable fluctuation in the control loop under manual mode is calculated using the following formula. Au j =0 indicates that formula (3) is in Au j When the value is 0, the calculation is performed; otherwise, the calculation of formula (3) at the j-th acquisition time is skipped. In step five, the mean value μ of the controlled variable in the control loop under automatic state is calculated using the following formula. au : Where p represents the p-th data collection time, and q represents the automatic activation status statistics, i.e., Au p When = 1, then q = 1, Au p When q = 0, then q = 0; PV jp Let Au represent the values ​​of p controlled variables, and Au p =1 indicates PV pq =PV p Au p =0 when there is PV pq =0.

4. The method for evaluating a distillation column control loop according to claim 2, characterized in that: In step six, the variance of the controlled variable fluctuation in the control loop under automatic conditions is calculated using the following formula. Au p =1 indicates that formula (5) is in Au p When = 1, the calculation is performed; otherwise, the calculation of formula (5) at the p-th acquisition time is skipped. In step seven, the integral of the absolute value of the error of the controlled variable in the automatic state is calculated using the following formula. au : Where x represents the x-th data collection time, Au x =1 indicates that formula (6) is in Au x When the value is 1, the calculation is performed; otherwise, the calculation of formula (6) at the xth acquisition time is skipped.

5. The method for evaluating a distillation column control loop according to claim 1, characterized in that: In step ten, the expected mean value of the controlled variable in the control loop under manual mode is used as the basis for the calculation. Calculate the mean score of the control loop in manual mode. In step eleven, the expected variance of the controlled variable under manual conditions is calculated. The fluctuation variance score of the control loop in manual mode 6. The method for evaluating a distillation column control loop according to claim 1, characterized in that: In step twelve, based on the expected mean value of the controlled variable of the loop in automatic mode... Calculate the mean score of the control loop in automatic mode. In step thirteen, based on the expected variance of the controlled variable under automatic conditions... Calculate the fluctuation variance score of the control loop in automatic mode.

7. The method for evaluating a distillation column control loop according to claim 1, characterized in that: In step fourteen, the integral of the absolute value of the expected error of the controlled variable under automatic state is calculated. Calculate the integral score of the absolute value of the error of the control loop in automatic mode.

8. The method for evaluating a distillation column control loop according to claim 1, characterized in that: In step fifteen, based on the l obtained in step eight... ma Step 10 And obtained in step eleven The evaluation score c for the control loop in manual operation mode ma : Where c 1ma c 2ma and c 3ma Weighted systems, typically c 1ma +c 2ma +c 3ma =1, and c 1ma ∈[0,1],c 2ma ∈[0,1-c 1ma ], c 3ma ∈[0,1-c 1ma -c 2ma ].

9. The method for evaluating a distillation column control loop according to claim 1, characterized in that: In step sixteen, based on the l obtained in step nine... au Step Twelve Step Thirteen and the result obtained in step fourteen The evaluation score c for the control loop in automatic operation mode au : Where c 1au c 2au c 3au and c 4au For a weighted system, a typical one is c. 1au +c 2au +c 3au +c 4au =1, and c 1au ∈[0,1]、c 2au ∈[0,1-c 1au ], c 3au ∈[0,1-c 1au -c 2au ] and c 4au ∈[0,1-c 1au -c 2au -c 3au ]; Step 17: Obtain the automatic activation rate η of the control loop and the evaluation score c of the control loop in manual operation mode. ma The evaluation score c of the control loop in automatic operation mode. au .

Images