Calculation method for standard blanking interval of aluminum electrolysis cell

Abstract

The invention relates to the technical field of aluminum electrolysis, in particular to a method for calculating a standard blanking interval of an aluminum electrolysis cell, which comprises the following steps of: S1, subdividing production time periods according to daily conditions of the electrolysis cell; s2, correcting the theoretical initial reference blanking interval NB0 according to the blanking feeding rate eta to obtain the initial reference blanking interval NBt0 = NB0 * eta; s3, obtaining a judgment factor TRGt and a reference blanking interval adjustment amplitude NBadj, obtaining a previous period reference blanking interval NBt-1, judging and calculating the reference blanking interval adjustment amplitude NBadj and the previous period reference blanking interval NBt-1 through the judgment factor TRGt to obtain a current period reference blanking interval NBt, and performing safety protection; and when the electrolysis is carried out to the next time period, the step is executed again. The reference blanking interval is automatically adjusted by designing a calculation method, and the refinement, intelligence and digitization level of electrolysis production management is improved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum electrolysis, and in particular to a method for calculating a reference material unloading interval of an aluminum electrolysis cell. Background Art

[0002] Electrolytic aluminum production is an important part of my country's aluminum industry and accounts for a relatively high proportion in the production of nonferrous metallurgical industry. Modern electrolytic aluminum production management is mainly divided into two aspects: inter-electrode distance management and alumina concentration management. In alumina concentration management, the alumina raw materials produced by electrolysis are supplied through interval feeding. The feeding rate of alumina is often characterized by the feeding interval. The theoretical feeding interval that matches the actual aluminum production efficiency of the electrolytic cell is called the reference feeding interval (NormalBreak—NB). However, it is difficult to accurately match the alumina feeding rate of the aluminum electrolytic cell with the actual aluminum production efficiency. In production, fluctuation management of over-feeding (~0.7NB) and under-feeding (~1.2NB) is often implemented. When the amount of material is excessive, the high concentration area in the aluminum electrolytic cell will not be able to dissolve alumina in time due to the local high concentration, resulting in precipitation and even the formation of a hard crust on the bottom of the furnace, increasing the horizontal current in the aluminum liquid and affecting the stability of the electrolytic cell; when the amount of material is insufficient, the low concentration area in the aluminum electrolytic cell will increase the possibility of flickering effect or even full cell effect due to the local low alumina concentration, increase energy consumption and reduce current efficiency; the periodic changes of excess and insufficient in the electrolytic cell will frequently cause impacts on the electrolyte superheat, local thermal balance and interface stability, and lose current efficiency. Therefore, it is very important to determine the reference feeding interval.

[0003] However, there is no standard algorithm or monitoring method for calculating the benchmark unloading interval. For a long time, the setting of this parameter has been based on the experience of production managers. Even under the same management concept, the benchmark unloading interval issued by different managers for the same electrolytic cell may deviate and be difficult to unify. With the increasingly urgent demand for intelligent and digital upgrades in my country's aluminum electrolysis industry in recent years, this problem has become more and more prominent, and it is urgent to develop an intelligent benchmark unloading interval calculation method. Summary of the invention

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for calculating the benchmark unloading interval of an aluminum electrolytic cell. By designing a calculation method, automatic adjustment of the benchmark unloading interval is achieved, thereby improving the refinement, intelligence and digitization level of electrolytic production management.

[0005] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0006] A method for calculating a reference feeding interval of an aluminum electrolytic cell comprises the following steps:

[0007] S1. Obtain the daily production management situation of the electrolytic cell, and subdivide the production period according to the daily production management situation of the electrolytic cell;

[0008] S2. Obtain the theoretical initial reference material cutting interval NB0 and the material cutting slot feeding rate η, and modify the theoretical initial reference material cutting interval NB0 according to the material cutting slot feeding rate η. The initial reference material cutting interval NB is calculated by the following formula t0 :

[0009] NB t0 =NB0×η;

[0010] S3. Obtain historical data and obtain the judgment factor TRG through historical data t Adjustment range NB with reference material cutting interval adj , obtain the previous period benchmark unloading interval NB t-1 , through the judgment factor TRG t Determine and calculate the adjustment range NB of the reference cutting interval adj The interval between the previous period and the benchmark material cutting is NB t-1 Get the current period benchmark unloading interval NB t , for safety protection; when the electrolysis proceeds to the next period, this step is performed again;

[0011] When this step is executed for the first time, the previous reference material cutting interval NB t-1 The value of is the initial reference blanking interval NB obtained in step S2 t0 The value of; when this step is executed later, the previous period benchmark unloading interval NB t-1 The value is the current period benchmark unloading interval NB of the previous period t The value of .

[0012] Furthermore, step S3 includes the following steps:

[0013] S31, obtaining historical data, the historical data including the number of effects AE in the previous period t-1 , flicker effect times GAE t-1 , high frequency noise HN t-1 , low frequency noise LN t-1 and pressure difference ΔV t-1 The voltage difference is the difference between the working voltage and the set voltage. The judgment factor TRG for the current period is calculated through historical data. t ,Right now:

[0014] TRG t =f(AE t-1 , GAE t-1 , HN t-1 , LN t-1 , ΔV t-1 )

[0015] S32, determine the judgment factor TRG of the current period t The upper limit of TRG up_limit And the lower limit TRG down_limit , and determine the adjustment range NB of the reference cutting interval adj ;

[0016] Make logical judgment 1:

[0017] When TRG t ≥TRG up_limit When the alarm signal is output, the current period benchmark unloading interval NB is manually set t ;

[0018] Make logical judgment 2:

[0019] When TRG down_limit <TRG t <TRG up_limit The current period benchmark unloading interval NB is calculated by the following formula: t :

[0020] NB t =NB t-1 -NB adj ;

[0021] When TRG t ≤TRG down_limit The current period benchmark unloading interval NB is calculated by the following formula: t :

[0022] NB t =NB t-1 +NB adj .

[0023] Furthermore, the step S3 further comprises the following steps:

[0024] S33, determine the upper limit NB of the reference material cutting interval up_limit and set the lower limit NB down_limit , for security protection;

[0025] When NB t >NB up_limit When up_limit The value is used as the benchmark unloading interval NB for the current period t ;

[0026] When NB t <NB down_limit When down_limit The value is used as the benchmark unloading interval NB for the current period t ;

[0027] When NB down_limit ≤NB t ≤NB up_limit When the current period of benchmark material cutting interval NB t No adjustments are made and it is issued as an instruction.

[0028] Furthermore, in step S1, the length of the subdivided time period is 1 to 72 hours.

[0029] Furthermore, the length of the subdivision period is determined by the health score of the electrolyzer:

[0030] When the health score is between 90 and 100, the period is 12 hours;

[0031] When the health score is between 80 and 90, the time period is 8 hours;

[0032] When the health score is between 70 and 80, the time period is 4 hours;

[0033] When the health score is between 60 and 70, the time period is 2 hours;

[0034] When the health score is less than 60 points, the time period is 1 hour.

[0035] Furthermore, in the step S2, the theoretical initial reference blanking interval NB0 is calculated through the aluminum tapping task.

[0036] Furthermore, the calculation of the reference unloading interval is restarted according to the electrolytic cell conditions and production conditions.

[0037] The beneficial effects of the present invention are:

[0038] The method for calculating the reference unloading interval of an aluminum electrolytic cell of the present invention divides the electrolytic production into time periods, and automatically adjusts the reference unloading interval in each time period based on historical data of the electrolytic cell and a scientific calculation method, forming a mathematical model, which is solidified into a control system, thereby reducing manual interference in electrolytic production management, being able to quickly and accurately calculate the reference unloading interval, solving the current situation in which this parameter has long been based on the experience of production managers, and improving the intelligence and digitization level of electrolytic production management. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention is a flow chart of a method for calculating a reference unloading interval of an aluminum electrolytic cell. DETAILED DESCRIPTION

[0040] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art.

[0041] like Figure 1 As shown, a method for calculating the reference feeding interval of an aluminum electrolytic cell comprises the following steps:

[0042] S1. Obtain the daily production management situation of the electrolytic cell, and subdivide the production period according to the daily production management situation of the electrolytic cell;

[0043] S2. Obtain the theoretical initial reference material cutting interval NB0 and the material cutting slot feeding rate η, and modify the theoretical initial reference material cutting interval NB0 according to the material cutting slot feeding rate η. The initial reference material cutting interval NB is calculated by the following formula t0 :

[0044] NB t0 =NB0×η;

[0045] S3. Obtain historical data and obtain the judgment factor TRG through historical data t Adjustment range NB with reference material cutting interval adj , obtain the previous period benchmark unloading interval NB t-1 , through the judgment factor TRG t Determine and calculate the adjustment range NB of the reference cutting interval adj The interval between the previous period and the benchmark material cutting is NB t-1 Get the current period benchmark unloading interval NB t , for safety protection; when the electrolysis proceeds to the next period, this step is performed again;

[0046] When this step is executed for the first time, the previous reference material cutting interval NB t-1 The value of is the initial reference blanking interval NB obtained in step S2 t0 The value of; when this step is executed later, the previous period benchmark unloading interval NB t-1 The value is the current period benchmark unloading interval NB of the previous period t The value of .

[0047] Specifically, step S3 includes the following steps:

[0048] S31, obtaining historical data, the historical data including the number of effects AE in the previous period t-1 , flicker effect times GAE t-1 , high frequency noise HNt-1 , low frequency noise LN t-1 and pressure difference ΔV t-1 The voltage difference is the difference between the working voltage and the set voltage. The judgment factor TRG for the current period is calculated through historical data. t ,Right now:

[0049] TRG t =f(AE t-1 , GAE t-1 , HN t-1 , LN t-1 , ΔV t-1 )

[0050] S32, determine the judgment factor TRG of the current period t The upper limit of TRG up_limit And the lower limit TRG down_limit , and determine the adjustment range NB of the reference cutting interval adj ;

[0051] Make logical judgment 1:

[0052] When TRG t ≥TRG up_limit When the alarm signal is output, the current period benchmark unloading interval NB is manually set t ;

[0053] Make logical judgment 2:

[0054] When TRG down_limit <TRG t <TRG up_limit The current period benchmark unloading interval NB is calculated by the following formula: t :

[0055] NB t =NB t-1 -NB adj ;

[0056] When TRG t ≤TRG down_limit The current period benchmark unloading interval NB is calculated by the following formula: t :

[0057] NB t =NB t-1 +NB adj .

[0058] Specifically, the step S3 further includes the following steps:

[0059] S33, determine the upper limit NB of the reference material cutting interval up_limit and set the lower limit NBdown_limit , for security protection;

[0060] When NB t >NB up_limit When up_limit The value is used as the benchmark unloading interval NB for the current period t ;

[0061] When NB t <NB down_limit When down_limit The value is used as the benchmark unloading interval NB for the current period t ;

[0062] When NB down_limit ≤NB t ≤NB up_limit When the current period of benchmark material cutting interval NB t No adjustments are made and it is issued as an instruction.

[0063] Specifically, in step S1, the length of the subdivided time period is 1 to 72 hours.

[0064] Specifically, the length of the subdivision period is determined by the health score of the electrolyzer:

[0065] When the health score is between 90 and 100, the period is 12 hours;

[0066] When the health score is between 80 and 90, the time period is 8 hours;

[0067] When the health score is between 70 and 80, the time period is 4 hours;

[0068] When the health score is between 60 and 70, the time period is 2 hours;

[0069] When the health score is less than 60 points, the time period is 1 hour.

[0070] The method for obtaining the health score can be obtained by using the online digital electrolytic cell health evaluation calculation method provided in Chinese Patent Publication No. CN110093632A.

[0071] Specifically, in step S2, the theoretical initial value NB0 of the reference unloading interval is calculated through the aluminum tapping task.

[0072] The calculation method of the aluminum output task can adopt a calculation method of the aluminum output task of an aluminum electrolytic cell provided by Chinese Patent Publication No. CN110413938B.

[0073] Specifically, the calculation of the reference feed interval is restarted according to the electrolytic cell conditions and production conditions. When the composition and physical and chemical properties of the alumina raw material undergo significant changes, the calculation is restarted and the above calculation process is repeated.

[0074] Embodiment 1:

[0075] In this embodiment, according to the health evaluation calculation method of Chinese Patent Publication No. CN110093632A, the health of the electrolytic cell is 95 points, and the length of the corresponding subdivision period is 12 hours, that is, every 12 hours is a subdivision period.

[0076] In this embodiment, step S3 is performed later, so step S2 is not calculated here, and the previous period benchmark unloading interval NB is directly calculated. t-1 Use 63.7 seconds.

[0077] In this embodiment, the judgment factor TRG t In step S31, the following formula is used for calculation:

[0078] TRG t =f(AE t-1 , GAE t-1 , HN t-1 , LN t-1 , ΔV t-1 )

[0079] =a1×AE t-1 +a2×GAE t-1 +a3×HN t-1 +a4×LN t-1 +a5×ΔV t-1

[0080] Among them, a1, a2, a3, a4 and a5 are weight coefficients. In this embodiment, a1 = 0.7, a2 = 0.25, a3 = 0.02, a4 = 0.02, a5 = 0.01, and the effect number AE of the previous period is t-1 =1, number of flickering effects GAE t-1 =3, high frequency noise HN t-1 =5, low frequency noise LN t-1 =1, pressure difference ΔV t-1 =7, substitute the value into the above formula to calculate the judgment factor TRG t is 1.64.

[0081] In this embodiment, the upper limit TRG of the judgment factor is up_limit is 3, the lower limit TRG is determined down_limit =1, the adjustment range of the reference cutting interval is NB adj is 0.2, and the above data is substituted into step S32 for logical judgment.t 1.64, between the upper limit TRG up_limit And the lower limit TRG down_limit The current period benchmark unloading interval NB t for:

[0082] NB t =NB t-1 -NB adj =63.7-0.2=63.5 seconds.

[0083] In this embodiment, the upper limit NB of the reference material feeding interval is set to up_limit Set the lower limit to 80 seconds. down_limit The above data is substituted into step S33 for safety protection. The NBt calculated in the previous step is 63.5 seconds, which is between the set upper limit NB up_limit and set the lower limit NB down_limit , then issue the instruction for the benchmark unloading interval NB for the current period t It is 63.5 seconds.

[0084] When the composition, physical and chemical properties of the alumina raw materials undergo significant changes, restart and repeat the above calculation process.

[0085] Embodiment 2:

[0086] In this embodiment, according to the health evaluation calculation method of Chinese Patent Publication No. CN110093632A, the health of the electrolytic cell is 75 points, and the length of the corresponding subdivision period is 4 hours, that is, every 4 hours is a subdivision period.

[0087] In this embodiment, step S3 is performed later, so step S2 is not calculated here, and the previous period benchmark unloading interval NB is directly calculated. t-1 Use 77 seconds.

[0088] In this embodiment, the judgment factor TRG t In step S31, the following formula is used for calculation:

[0089] TRG t =f(AE t-1 , GAE t-1 , HN t-1 , LN t-1 , ΔV t-1 )

[0090] =a1×AE t-1 +a2×GAE t-1

[0091] Among them, a1 and a2 are weight coefficients. In this embodiment, a1=0.8, a2=0.2, and the effect times AE in the previous period aret-1 =0, flickering effect times GAE t-1 =1, the operating system of this embodiment does not consider high-frequency noise HN t-1 , low frequency noise LN t-1 and pressure difference ΔV t-1 , Substitute the value into the above formula to calculate the judgment factor TRG t is 0.2.

[0092] In this embodiment, the upper limit TRG of the judgment factor is up_limit is 2, the lower limit TRG is determined down_limit The adjustment range of the reference material cutting interval is NB. adj is 0.2, and the above data is substituted into step S32 for logical judgment. t 0.2, which is less than the lower limit TRG down_limit , then the benchmark unloading interval NB for the current period t for:

[0093] NB t =NB t-1 +NB adj =77+0.2=77.2 seconds.

[0094] In this embodiment, the upper limit NB of the reference material feeding interval is set to up_limit 77 seconds, set the lower limit NB down_limit is 60 seconds. Substitute the above data into step S33 for security protection. The NB calculated in the previous step is t 77.2 seconds, which is greater than the upper limit NB up_limit , then issue the instruction for the benchmark unloading interval NB for the current period t It is 77 seconds.

[0095] When the composition, physical and chemical properties of the alumina raw materials undergo significant changes, restart and repeat the above calculation process.

[0096] Embodiment 3:

[0097] This embodiment is basically the same as the second embodiment, except that: in the calculation of step S31, the number of effects AE in the previous period of this embodiment is t-1 =4, flickering effect times GAE t-1 =10, the judgment factor TRG is calculated t is 5.2. Judgment factor TRG t Greater than the upper limit TRG up_limit , output alarm signal, lead to manual adjustment, manually input the benchmark unloading interval NB of the current period t is 60 seconds.

[0098] Embodiment 4:

[0099] This embodiment is basically the same as the embodiment 1, except that: instead of using the values ​​provided in the embodiment 1, this embodiment uses the current period reference unloading interval NB t The upper limit of the standard unloading interval is 59.5 seconds. up_limit Set the lower limit to 80 seconds. down_limit The current period benchmark unloading interval is NB, which is 60 seconds. t Less than the set lower limit NB down_limit , then issue the instruction for the benchmark unloading interval NB for the current period t is 60 seconds.

[0100] Embodiment 5:

[0101] This embodiment is basically the same as the embodiment 1, except that: in this embodiment, step S3 is executed for the first time. In step S2, according to the aluminum discharge task calculation method of Chinese patent publication number CN110413938B, the theoretical initial reference unloading interval NB0 is calculated to be 65 seconds. In this embodiment, the unloading amount of aluminum oxide in the electrolytic cell has a flying loss of about 2%, so the unloading rate η of aluminum oxide is 98%, and the initial reference unloading interval NB0 is calculated to be t-1 It is 63.7 seconds, which is used as the reference unloading interval NB at the previous moment in S3 t-1 The subsequent calculation is the same as that in Example 1 and will not be repeated here.

[0102] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for calculating the reference feeding interval of an aluminum electrolytic cell, characterized in that: The following steps are involved: S1. Obtain the daily production management situation of the electrolytic cell, and subdivide the production period according to the daily production management situation of the electrolytic cell; S2. Obtain the theoretical initial reference material cutting interval NB0 and the material cutting slot feeding rate η, and modify the theoretical initial reference material cutting interval NB0 according to the material cutting slot feeding rate η. The initial reference material cutting interval NB is calculated by the following formula t0 : NB t0 =NB0×η; S3. Obtain historical data and obtain the judgment factor TRG through historical data t And the adjustment range of the reference cutting interval NBad j , obtain the previous period benchmark unloading interval NBt -1 , through the judgment factor TRGt, calculate the adjustment range of the reference cutting interval NBad j NBt with the previous period benchmark cutting interval -1 Get the current period benchmark unloading interval NB t , for safety protection; when the electrolysis proceeds to the next period, this step is performed again; When this step is executed for the first time, the previous reference material cutting interval NB t-1 The value of is the initial reference blanking interval NB obtained in step S2 t0 The value of; when this step is executed later, the previous period benchmark unloading interval NB t-1 The value is the current period benchmark unloading interval NB of the previous period t The value of .

2. A method for calculating the reference feeding interval of an aluminum electrolytic cell according to claim 1, characterized in that: The step S3 comprises the following steps: S31, obtaining historical data, the historical data including the number of effects AE in the previous period t-1 , flicker effect times GAE t-1 , high frequency noise HN t-1 , low frequency noise LN t-1 and pressure difference ΔV t-1 The voltage difference is the difference between the working voltage and the set voltage. The judgment factor TRG for the current period is calculated through historical data. t ,Right now: TRG=f(AE1,GAE1,HN-1,LN1,ΔV-1) S32, determine the upper limit TRGup_limit and lower limit TRGdown_limit of the judgment factor TRGt in the current period, and determine the adjustment range NBad of the reference feeding interval j ; Make logical judgment 1: When TRGt≥TRGup_limit, an alarm signal is output and the current period benchmark unloading interval NB is manually set. t ; Make logical judgment 2: When TRG down_limit <TRG t <TRG up_limit The current period benchmark unloading interval NB is calculated by the following formula: t : NB t =NB t-1 -NB adj ; When TRG t ≤TRG down_limit The current period benchmark unloading interval NB is calculated by the following formula: t : NB t =NB t-1 +NB adj 。 3. A method for calculating the reference feeding interval of an aluminum electrolytic cell according to claim 2, characterized in that: The step S3 further comprises the following steps: S33, determine the upper limit NB of the reference material cutting interval up_limit and set the lower limit NB down_limit , for security protection; When NB t >NB up_limit When up_limit The value is used as the benchmark unloading interval NB for the current period t ; When NB t <NB down_limit When down_limit The value is used as the benchmark unloading interval NB for the current period t ; When NB down_limit ≤NB t ≤NB up_limit When the current period of benchmark material cutting interval NB t No adjustments are made and it is issued as an instruction.

4. A method for calculating the reference feeding interval of an aluminum electrolytic cell according to claim 1, characterized in that: In the step S1, the length of the subdivided time period is 1 to 72 hours.

5. A method for calculating the reference feeding interval of an aluminum electrolytic cell according to claim 4, characterized in that: The length of the subdivision period is determined by the electrolyzer's health score: When the health score is between 90 and 100, the period is 12 hours; When the health score is between 80 and 90, the period is 8 hours; When the health score is between 70 and 80, the time period is 4 hours; When the health score is between 60 and 70, the time period is 2 hours; When the health score is less than 60 points, the time period is 1 hour.

6. A method for calculating the reference feeding interval of an aluminum electrolytic cell according to claim 1, characterized in that: In the step S2, the theoretical initial reference unloading interval NB0 is calculated through the aluminum discharge task.

7. A method for calculating a reference feeding interval of an aluminum electrolytic cell according to any one of claims 1 to 6, characterized in that: Restart the calculation of the benchmark unloading interval based on the electrolytic cell conditions and production conditions.

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