A method and system for controlling pre-wash acid water content in hydrofluoric acid production

Abstract

The invention relates to a method and system for controlling the water content of pre-washing acid in hydrofluoric acid production, wherein the method comprises: S1, receiving setting parameters of a hydrofluoric acid production process input by an operator; S2, collecting variable parameters of the hydrofluoric acid production process read by a DCS; S3, based on the setting parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, using a preset target function for predicting the hydrofluoric acid water content of the pre-washing acid to obtain a predicted value of the hydrofluoric acid water content of the pre-washing acid; S4, receiving a set value of the water content of the pre-washing acid, a set value of the temperature of a mixed acid tank and constraints input by the operator; S5, adjusting the water content of the pre-washing acid in the hydrofluoric acid production process based on the predicted value of the hydrofluoric acid water content of the pre-washing acid and the set value of the water content of the pre-washing acid, the set value of the temperature of a mixed acid tank and constraints input by the operator.

Description

Technical Field

[0001] The present invention relates to the technical field of anhydrous hydrofluoric acid production in fluorine chemical industry, and in particular to a method and system for controlling the content of pre-wash acid water in hydrofluoric acid production. Background Art

[0002] The hydrofluoric acid unit is the most important production unit in the fluorine chemical industry, and hydrofluoric acid products are the main raw materials for the production of lithium batteries, chips, display screens, etc. The products are closely related to the national economy and people's lives. With the rapid development of the national economy and the gradual improvement of people's living standards, the market's requirements for the quality of hydrofluoric acid products are also gradually increasing. The main quality indicators of hydrofluoric acid products include purity, moisture content, sulfur dioxide content, sulfate content, etc. The moisture content of the pre-wash acid will affect the conversion rate of the hydrofluoric acid preparation reaction and the impurity content of the product. If the ratio of 98% sulfuric acid to 105% sulfuric acid is not properly controlled, the concentration of sulfuric acid after mixing in the mixed acid tank is not appropriate, and the control is easy to cause impurities such as water, sulfur dioxide, and sulfuric acid to enter the anhydrous hydrofluoric acid product, making the quality control of anhydrous hydrofluoric acid more difficult. At the same time, the equipment is severely corroded, which reduces the production and operation cycle of the device. In order to improve the quality of hydrofluoric acid products, it is necessary to stably control the moisture content of the sulfuric acid raw material entering the mixed acid tank. The current control scheme is generally to collect samples for testing and analysis in the laboratory, and the operator adjusts the ratio of sulfuric acid to fluorite, 98% sulfuric acid and 105% sulfuric acid according to the test results, and controls the moisture content of the sulfuric acid raw material before mixing within a certain range, thereby improving the quality of the hydrofluoric acid product. Due to the lack of effective detection means, it is impossible to obtain the moisture content of the sulfuric acid raw material in the mixed acid tank in real time. This scheme is based on the laboratory analysis results of the quality of the hydrofluoric acid product, has a large lag, is not timely, and cannot achieve automatic control, and cannot provide convenient conditions for the subsequent impurity removal unit of the hydrofluoric acid product. At the same time, due to the lack of a data platform, it also brings huge challenges to the intelligence of the device. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method and system for controlling the water content of pre-wash acid in hydrofluoric acid production, which solves the technical problem that the current main control method is that the production operator adjusts the ratio of 98% sulfuric acid to 105% sulfuric acid according to the laboratory analysis result data to achieve manual adjustment, and the laboratory analysis result of the water content of the pre-wash acid has a large hysteresis, the adjustment of the ratio of 98% sulfuric acid to 105% sulfuric acid is delayed, and the water content of the pre-wash acid is difficult to control.

[0005] (II) Technical solution

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] In a first aspect, an embodiment of the present invention provides a method for controlling the content of pre-wash acid water in hydrofluoric acid production, the method comprising:

[0008] S1. receiving setting parameters of the hydrofluoric acid production process input by an operator;

[0009] S2. Collect variable parameters of the hydrofluoric acid production process read by DCS;

[0010] S3, based on the set parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, using a preset objective function for predicting the water content of the pre-washing acid hydrofluoric acid, obtaining a predicted value of the water content of the pre-washing acid hydrofluoric acid;

[0011] S4, receiving the pre-wash acid moisture setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator;

[0012] S5. Adjust the pre-wash acid water content in the hydrofluoric acid production process based on the predicted value of the pre-wash acid hydrofluoric acid water content and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and constraints input by the operator.

[0013] Preferably, the setting parameters of the hydrofluoric acid production process input by the operator in S1 include:

[0014] Pre-wash acid moisture setting value Y sp , Mixed acid tank temperature setting value T sp 、The minimum value F of the constraint range of 98% sulfuric acid flow rate f1 1f_min 、The maximum value F of the constraint range of 98% sulfuric acid flow rate f1 1f_max 、The minimum value F of the constraint range of 105% sulfuric acid flow rate f2 2f_min , the maximum value F of the constraint range of 105% sulfuric acid flow f2 2f_max .

[0015] Preferably, the variable parameters of the hydrofluoric acid production process read by the DCS in the hydrofluoric acid production process collected in S2 include: the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank, the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank, the actual flow rate f3 of fluorite calcium fluoride entering the reactor in the hydrofluoric acid production process, the actual flow rate f4 of 98% sulfuric acid entering the absorption tower, and the temperature T3 of the mixed acid tank in the hydrofluoric acid production process.

[0016] Preferably, before S1, the method further includes:

[0017] S0, collecting the variable parameters of the hydrofluoric acid production process in the historical stage and the corresponding actual hydrofluoric acid water content of the pre-wash acid, and using the least squares method to minimize the sum of squares of the errors for the historical data and the laboratory data to determine the objective function for predicting the hydrofluoric acid water content of the pre-wash acid;

[0018] Among them, the objective function of the water content prediction of pre-wash acid hydrofluoric acid is:

[0019] Y m =ɑ0+ɑ1·p1+ɑ2·p2+ɑ3·f 3+ ɑ4·T 3+ ɑ5·T3·T3;

[0020] Among them, Y m It indicates the predicted value of water content of pre-wash acid hydrofluoric acid;

[0021] ɑ j (j=0, 1, 2, 3, 4, 5) is the regression coefficient;

[0022] p1 is the total acid to fluorite ratio of 98% sulfuric acid and 105% sulfuric acid;

[0023] p2 is a ratio of 98% sulfuric acid to 105% sulfuric acid.

[0024] Preferably,

[0025] The total acid to fluorite ratio p1 of 98% sulfuric acid and 105% sulfuric acid is calculated in advance by formula (1);

[0026] Wherein, formula (1) is:

[0027]

[0028] ρ1 is the density of 98% sulfuric acid;

[0029] ρ2 is the density of 105% sulfuric acid;

[0030] ρ3 is the density of fluorite calcium fluoride.

[0031] Preferably,

[0032] Among them, the ratio p2 of 98% sulfuric acid to 105% sulfuric acid is calculated by formula (2);

[0033] Wherein, formula (2) is:

[0034]

[0035] Preferably, S5 specifically includes:

[0036] S51, based on the predicted value Y of the pre-wash acid hydrofluoric acid water content mThe target value F1 of the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank are obtained by using the pre-set process setting objective function and the pre-wash acid water content setting, the mixed acid tank temperature setting and the constraint conditions input by the operator;

[0037] The process setting objective function is:

[0038] MIN(Y m , T3) = f(F1, F2, Y sp , T sp );

[0039] F1 is the calculated target value for 98% sulfuric acid;

[0040] F2 is the calculated target value for 105% sulfuric acid;

[0041] f() is the model prediction algorithm MPC.

[0042] S52, controlling the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank to be respectively the same as the target value F1 of the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank, so as to adjust the pre-wash acid water content in the hydrofluoric acid production process.

[0043] Preferably,

[0044] The constraints include:

[0045] -ε1 <Y m -Y sp <ε1;

[0046] -ε2 <T3-T sp <ε2;

[0047] P 1p_min <p1<P 1p_max ;

[0048] F 1f_min <f1<F 1f_max ;

[0049] F 2f_min <f2<F 2f_max ;

[0050] Where: ε1 is the first preset value;

[0051] ε2 is a second preset value;

[0052] P 1p_min It is the minimum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid;

[0053] P 1p_max It is the maximum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid;

[0054] F 1f_min is the minimum value of the constraint range of 98% sulfuric acid flow rate f1;

[0055] F 1f_max is the maximum value of the constraint range of 98% sulfuric acid flow rate f1;

[0056] F 2f_min The minimum value of the constraint range of 105% sulfuric acid flow rate f2;

[0057] F 2f_max It is the maximum value of the constraint range of 105% sulfuric acid flow rate f2.

[0058] On the other hand, this embodiment also provides a pre-wash acid water content control system in hydrofluoric acid production, the system comprising:

[0059] A receiving module, used for receiving setting parameters of a hydrofluoric acid production process input by an operator;

[0060] The acquisition module is used to collect the variable parameters of the hydrofluoric acid production process read by the DCS;

[0061] A prediction module, for obtaining a predicted value of the hydrofluoric acid water content of the pre-washing acid by using a preset objective function for predicting the hydrofluoric acid water content of the pre-washing acid based on the set parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS;

[0062] A constraint module, used for receiving the pre-wash acid moisture set value, the mixed acid tank temperature set value and constraint conditions input by the operator;

[0063] The control module is used to adjust the pre-wash acid water content in the hydrofluoric acid production process based on the predicted value of the pre-wash acid hydrofluoric acid water content and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator.

[0064] Preferably, the system further comprises:

[0065] The prompt module is used to output information to remind the operator to adjust the constraints when the constraints cannot be met.

[0066] (III) Beneficial effects

[0067] The beneficial effects of the present invention are as follows: a method and system for controlling the water content of pre-wash acid in hydrofluoric acid production of the present invention adopts the setting parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, adopts the pre-set target function of the hydrofluoric acid water content prediction of the pre-wash acid, obtains the predicted value of the hydrofluoric acid water content of the pre-wash acid; based on the predicted value of the hydrofluoric acid water content of the pre-wash acid and the pre-wash acid water content setting value, the temperature setting value of the mixed acid tank and the constraint conditions input by the operator, the water content of the pre-wash acid in the hydrofluoric acid production process is adjusted. The water content of the pre-wash acid is predicted by the pre-set target function of the hydrofluoric acid water content prediction of the pre-wash acid, eliminates the lag of all laboratory data, and realizes the automatic and stable control of the water content of the pre-wash acid. The technical problem that the current main control method is that the production operator adjusts the ratio of 98% sulfuric acid to 105% sulfuric acid according to the laboratory analysis result data to achieve manual adjustment, and the laboratory analysis result of the water content of the pre-wash acid has a large lag, the ratio adjustment of 98% sulfuric acid to 105% sulfuric acid is lagging, and the water content of the pre-wash acid is difficult to control is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 A flow chart of a method for controlling the content of pre-wash acid water in hydrofluoric acid production according to the present invention;

[0069] Figure 2 This is a flow chart of a method for controlling the content of pre-wash acid water in hydrofluoric acid production in Embodiment 2 of the present invention;

[0070] Figure 3 This is a schematic diagram of the structure of a control system for pre-wash acid water content in hydrofluoric acid production in Example 2 of the present invention;

[0071] Figure 4 This is a schematic diagram of the structure of another control system for pre-wash acid water content in hydrofluoric acid production in Example 2 of the present invention;

[0072] Figure 5 A schematic diagram showing the comparison effect between the predicted value of the water content of pre-wash acid hydrofluoric acid obtained by using a method for controlling the water content of pre-wash acid in hydrofluoric acid production of the present invention and laboratory data;

[0073] Figure 6 The present invention is a process flow chart of the reaction part of the hydrofluoric acid product preparation in the prior art. DETAILED DESCRIPTION

[0074] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0075] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. 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 described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0076] The process diagram of the hydrofluoric acid product preparation reaction is as follows: Figure 6 As shown, 98% sulfuric acid raw materials are divided into two routes. One route first enters the absorption tower to absorb the gas in the tail gas, and then enters the pre-washing acid tank. The sulfuric acid in the pre-washing acid tank is circulated by a pump to absorb the crude hydrofluoric acid gas in the pre-purification tower. The other route directly enters the mixed acid tank; 105% sulfuric acid directly enters the mixed acid tank and is mixed with 98% before entering the reactor; fluorite enters the reactor after raw material drying, and fluorite reacts with sulfuric acid in the reactor to generate crude hydrofluoric acid gas that enters the pre-purification tower for pre-purification.

[0077] Embodiment 1

[0078] The method for controlling the pre-wash acid water content in the production of hydrofluoric acid in this embodiment is aimed at the above Figure 6 The control method in the hydrofluoric acid product preparation reaction part process shown in FIG.

[0079] See also Figure 1 This embodiment provides a method for controlling the content of pre-wash acid water in hydrofluoric acid production, the method comprising:

[0080] S1. Receive the setting parameters of the hydrofluoric acid production process input by the operator, including:

[0081] Pre-wash acid moisture setting value Y sp , Mixed acid tank temperature setting value T sp 、The minimum value F of the constraint range of 98% sulfuric acid flow rate f1 1f_min 、The maximum value F of the constraint range of 98% sulfuric acid flow rate f1 1f_max 、The minimum value F of the constraint range of 105% sulfuric acid flow rate f2 2f_min , the maximum value F of the constraint range of 105% sulfuric acid flow f2 2f_max .

[0082] S2. Collect the variable parameters of the hydrofluoric acid production process read by DCS, including: the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank, the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank, the actual flow rate f3 of fluorite calcium fluoride entering the reactor in the hydrofluoric acid production process, the actual flow rate f4 of 98% sulfuric acid entering the absorption tower, and the temperature T3 of the mixed acid tank in the hydrofluoric acid production process.

[0083] S3. Based on the setting parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, a pre-set objective function for predicting the water content of the pre-washing acid hydrofluoric acid is used to obtain a predicted value of the water content of the pre-washing acid hydrofluoric acid.

[0084] S4, receiving the pre-wash acid moisture setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator.

[0085] S5. Adjust the pre-wash acid water content in the hydrofluoric acid production process based on the predicted value of the pre-wash acid hydrofluoric acid water content and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and constraints input by the operator.

[0086] In the practical application of this embodiment, before S1, the following steps are also included:

[0087] S0. Collect the variable parameters of the hydrofluoric acid production process in the historical stage and the corresponding actual hydrofluoric acid water content of the pre-wash acid, and use the least squares method to minimize the sum of squares of errors for the historical data and laboratory data to determine the objective function of the pre-wash acid hydrofluoric acid water content prediction.

[0088] Among them, the objective function of the water content prediction of pre-wash acid hydrofluoric acid is:

[0089] Y m =ɑ0+ɑ1·p1+ɑ2·p2+ɑ3·f 3+ ɑ4·T 3+ ɑ5·T3·T3;

[0090] Among them, Y m Indicates the predicted value of water content in pre-wash acid hydrofluoric acid.

[0091] ɑ j (j=0, 1, 2, 3, 4, 5) is the regression coefficient.

[0092] p1 is the total acid to fluorite ratio of 98% sulfuric acid and 105% sulfuric acid.

[0093] p2 is a ratio of 98% sulfuric acid to 105% sulfuric acid.

[0094] The total acid ratio of 98% sulfuric acid to 105% sulfuric acid to fluorite p1 is calculated in advance by formula (1).

[0095] Wherein, formula (1) is:

[0096]

[0097] ρ1 is the density of 98% sulfuric acid.

[0098] ρ2 is the density of 105% sulfuric acid.

[0099] ρ3 is the density of fluorite calcium fluoride.

[0100] The ratio p2 of 98% sulfuric acid to 105% sulfuric acid is calculated by formula (2).

[0101] Formula (2) is:

[0102]

[0103] Specifically, S5 includes:

[0104] S51, based on the predicted value Y of the pre-wash acid hydrofluoric acid water content m The pre-set process setting objective function is used with the pre-wash acid moisture setting, mixed acid tank temperature setting and constraints input by the operator to obtain the target value F1 of the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank.

[0105] The constraints include:

[0106] -ε1 <Y m -Y sp <ε1;

[0107] -ε2 <T3-T sp <ε2;

[0108] P 1p_min <p1<P 1p_max ;

[0109] F 1f_min <f1<F 1f_max ;

[0110] F 2f_min <f2<F 2f_max ;

[0111] Wherein: ε1 is the first preset value.

[0112] ε2 is a second preset value.

[0113] P 1p_min It is the minimum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid.

[0114] P 1p_max It is the maximum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid.

[0115] F 1f_min It is the minimum value of the constraint range of 98% sulfuric acid flow rate f1.

[0116] F 1f_maxIt is the maximum value of the constraint range of 98% sulfuric acid flow rate f1.

[0117] F 2f_min It is the minimum value of the constraint range of 105% sulfuric acid flow rate f2.

[0118] F 2f_max It is the maximum value of the constraint range of 105% sulfuric acid flow rate f2.

[0119] The process setting objective function is:

[0120] MIN(Y m , T3) = f(F1, F2, Y sp , T sp );

[0121] F1 is the calculated target value for 98% sulfuric acid.

[0122] F2 is the calculated target value for 105% sulfuric acid.

[0123] f() is the model prediction algorithm MPC.

[0124] S52, controlling the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank to be respectively the same as the target value F1 of the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank, so as to adjust the pre-wash acid water content in the hydrofluoric acid production process.

[0125] The invention discloses a method for controlling the water content of pre-wash acid in hydrofluoric acid production. The method adopts the setting parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, adopts the pre-set target function of the hydrofluoric acid water content prediction of the pre-wash acid, obtains the predicted value of the hydrofluoric acid water content of the pre-wash acid; and adjusts the water content of the pre-wash acid in the hydrofluoric acid production process based on the predicted value of the hydrofluoric acid water content of the pre-wash acid and the pre-wash acid water content setting value, the temperature setting value of the mixed acid tank and the constraint conditions. The water content of the pre-wash acid is predicted by the pre-set target function of the hydrofluoric acid water content prediction of the pre-wash acid, eliminates the hysteresis of all laboratory data, and realizes the automatic and stable control of the water content of the pre-wash acid. The method solves the technical problems that the current main control method is that the production operator adjusts the ratio of 98% sulfuric acid to 105% sulfuric acid according to the laboratory analysis result data to realize manual adjustment, and the laboratory analysis result of the water content of the pre-wash acid has a large hysteresis, the ratio adjustment of 98% sulfuric acid to 105% sulfuric acid is delayed, and the water content of the pre-wash acid is difficult to control.

[0126] Embodiment 2

[0127] See also Figure 2This embodiment provides a method for controlling the content of pre-wash acid water in hydrofluoric acid production, the method comprising:

[0128] 101. Collect the variable parameters of the hydrofluoric acid production process in the historical stage and the corresponding actual hydrofluoric acid water content of the pre-wash acid, and use the least squares method to minimize the sum of squares of errors for the historical data and laboratory data to determine the objective function of the hydrofluoric acid water content prediction of the pre-wash acid.

[0129] Among them, the objective function of the water content prediction of pre-wash acid hydrofluoric acid is:

[0130] Y m =ɑ0+ɑ1·p1+ɑ2·p2+ɑ3·f 3+ ɑ4·T 3+ ɑ5·T3·T3;

[0131] Among them, Y m Indicates the predicted value of water content in pre-wash acid hydrofluoric acid.

[0132] ɑ j (j=0, 1, 2, 3, 4, 5) is the regression coefficient.

[0133] p1 is the total acid to fluorite ratio of 98% sulfuric acid and 105% sulfuric acid.

[0134] p2 is a ratio of 98% sulfuric acid to 105% sulfuric acid.

[0135] The total acid ratio of 98% sulfuric acid to 105% sulfuric acid to fluorite p1 is calculated in advance by formula (1).

[0136] Wherein, formula (1) is:

[0137]

[0138] ρ1 is the density of 98% sulfuric acid.

[0139] ρ2 is the density of 105% sulfuric acid.

[0140] ρ3 is the density of fluorite calcium fluoride.

[0141] Among them, the ratio p2 of 98% sulfuric acid to 105% sulfuric acid is calculated by formula (2);

[0142] Formula (2) is:

[0143]

[0144] Since the on-site production process load is constantly changing, the actual flow rate f3 of fluorite calcium fluoride entering the reactor in the hydrofluoric acid production process will be adjusted according to the actual situation. Automatic control is not considered. Only the change of fluorite calcium fluoride feed is considered that the total acid amount of sulfuric acid needs to be matched. Therefore, the total acid and fluorite ratio calculation formula of 98% sulfuric acid and 105% sulfuric acid is calculated according to formula (1) and formula (2).

[0145] 102. Receive the set parameters of the hydrofluoric acid production process input by the operator, including:

[0146] Pre-wash acid moisture setting value Y sp , Mixed acid tank temperature setting value T sp 、The minimum value F of the constraint range of 98% sulfuric acid flow rate f1 1f_min 、The maximum value F of the constraint range of 98% sulfuric acid flow rate f1 1f_max 、The minimum value F of the constraint range of 105% sulfuric acid flow rate f2 2f_min , the maximum value F of the constraint range of 105% sulfuric acid flow f2 2f_max .

[0147] 103. Collect variable parameters of the hydrofluoric acid production process read by DCS, including: the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank, the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank, the actual flow rate f3 of fluorite calcium fluoride entering the reactor in the hydrofluoric acid production process, the actual flow rate f4 of 98% sulfuric acid entering the absorption tower, and the temperature T3 of the mixed acid tank in the hydrofluoric acid production process.

[0148] 104. Based on the set parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, a pre-set objective function for predicting the water content of the pre-washing acid hydrofluoric acid is used to obtain a predicted value of the water content of the pre-washing acid hydrofluoric acid.

[0149] 105. Receive the pre-wash acid moisture set value, the mixed acid tank temperature set value and the constraint conditions input by the operator.

[0150] 106. Adjust the pre-wash acid water content in the hydrofluoric acid production process based on the predicted value of the pre-wash acid hydrofluoric acid water content and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and constraint conditions input by the operator.

[0151] Specifically, 106 specifically includes: based on the predicted value Y of the pre-wash acid hydrofluoric acid water content m The pre-set process setting objective function is used with the pre-wash acid moisture setting, mixed acid tank temperature setting and constraints input by the operator to obtain the target value F1 of the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank.

[0152] The constraints include:

[0153] -ε1 <Y m -Y sp <ε1;

[0154] -ε2 <T3-T sp <ε2;

[0155] P 1p_min <p1<P 1p_max ;

[0156] F 1f_min <f1<F 1f_max ;

[0157] F 2f_min <f2<F 2f_max ;

[0158] Wherein: ε1 is the first preset value.

[0159] ε2 is a second preset value.

[0160] P 1p_min It is the minimum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid.

[0161] P 1p_max It is the maximum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid.

[0162] F 1f_min It is the minimum value of the constraint range of 98% sulfuric acid flow rate f1.

[0163] F 1f_max It is the maximum value of the constraint range of 98% sulfuric acid flow rate f1.

[0164] F 2f_min It is the minimum value of the constraint range of 105% sulfuric acid flow rate f2.

[0165] F 2f_max It is the maximum value of the constraint range of 105% sulfuric acid flow rate f2.

[0166] The process setting objective function is:

[0167] MIN(Y m , T3) = f(F1, F2, Y sp , T sp );

[0168] F1 is the calculated target value for 98% sulfuric acid.

[0169] F2 is the calculated target value for 105% sulfuric acid.

[0170] f() is the model prediction algorithm MPC.

[0171] The actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank are controlled to be the same as the target value F1 of the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank, respectively, so as to adjust the pre-wash acid water content in the hydrofluoric acid production process.

[0172] The present invention discloses a method for controlling the water content of pre-wash acid in hydrofluoric acid production. The method adopts the setting parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, adopts the pre-set target function for predicting the hydrofluoric acid water content of the pre-wash acid, obtains the predicted value of the hydrofluoric acid water content of the pre-wash acid; and adjusts the water content of the pre-wash acid in the hydrofluoric acid production process based on the predicted value of the hydrofluoric acid water content of the pre-wash acid and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator. The water content of the pre-wash acid is predicted by the pre-set target function for predicting the hydrofluoric acid water content of the pre-wash acid, eliminates the hysteresis of all laboratory data, and realizes the automatic and stable control of the water content of the pre-wash acid.

[0173] Embodiment 3

[0174] See also Figure 3 This embodiment provides a control system for pre-wash acid water content in hydrofluoric acid production, the system comprising:

[0175] The receiving module is used to receive the setting parameters of the hydrofluoric acid production process input by the operator.

[0176] The acquisition module is used to acquire the variable parameters of the hydrofluoric acid production process read by the DCS.

[0177] The prediction module is used to obtain the predicted value of the hydrofluoric acid water content of the pre-washing acid based on the set parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, using a preset objective function for predicting the water content of the pre-washing acid hydrofluoric acid.

[0178] The constraint module is used to receive the pre-wash acid moisture set value, the mixed acid tank temperature set value and the constraint conditions input by the operator.

[0179] The control module is used to adjust the pre-wash acid water content in the hydrofluoric acid production process based on the predicted value of the pre-wash acid hydrofluoric acid water content and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator.

[0180] See also Figure 4 The system in this embodiment also includes: a prompt module, which is used to output information to remind the operator to adjust the constraints when the constraints cannot be met.

[0181] In this embodiment, a control system for the water content of pre-wash acid in hydrofluoric acid production utilizes the exothermic thermodynamic properties of the mixture of sulfuric acid and water to achieve predictive calculation and predictive control of the water content of pre-wash acid. In this embodiment, each module in a control system for the water content of pre-wash acid in hydrofluoric acid production can be implemented on the central control APC-Studio 3.0 intelligent design platform.

[0182] This embodiment provides a control system for pre-wash acid water content in hydrofluoric acid production, which can execute a method for controlling pre-wash acid water content in hydrofluoric acid production in each of the above embodiments.

[0183] Experimental results

[0184] See also Figure 5 , a comparison diagram of the effect of a method for controlling the pre-wash acid water content in hydrofluoric acid production performed by a control system for the pre-wash acid water content in hydrofluoric acid production provided by this embodiment and the effect of laboratory test data is provided. It can be clearly seen that the control of the pre-wash acid water content in hydrofluoric acid production using the present invention is very close to the prediction of the laboratory test data and is ahead of the laboratory data.

[0185] The present invention discloses a method for controlling the water content of pre-wash acid in hydrofluoric acid production. The method adopts the setting parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, adopts the pre-set target function for predicting the hydrofluoric acid water content of the pre-wash acid, obtains the predicted value of the hydrofluoric acid water content of the pre-wash acid; and adjusts the water content of the pre-wash acid in the hydrofluoric acid production process based on the predicted value of the hydrofluoric acid water content of the pre-wash acid and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator. The water content of the pre-wash acid is predicted by the pre-set target function for predicting the hydrofluoric acid water content of the pre-wash acid, eliminates the hysteresis of all laboratory data, and realizes the automatic and stable control of the water content of the pre-wash acid.

[0186] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0187] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0188] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0189] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0190] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0191] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A method for controlling the content of pre-wash acid water in hydrofluoric acid production, characterized in that: The method comprises: S1. receiving setting parameters of the hydrofluoric acid production process input by an operator; S2. Collect variable parameters of the hydrofluoric acid production process read by DCS; The variable parameters of the hydrofluoric acid production process read by the DCS in the hydrofluoric acid production process collected in S2 include: the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank, the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank, the actual flow rate f3 of fluorite calcium fluoride entering the reactor in the hydrofluoric acid production process, the actual flow rate f4 of 98% sulfuric acid entering the absorption tower, and the temperature T3 of the mixed acid tank in the hydrofluoric acid production process; S3, based on the set parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS, using a preset objective function for predicting the water content of the pre-washing acid hydrofluoric acid, obtaining a predicted value of the water content of the pre-washing acid hydrofluoric acid; S4, receiving the pre-wash acid moisture setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator; S5, based on the pre-wash acid hydrofluoric acid water content predicted value and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and the constraints input by the operator, adjusting the pre-wash acid water content in the production hydrofluoric acid process; Before S1, it also includes: S0, collecting the variable parameters of the hydrofluoric acid production process in the historical stage and the corresponding actual hydrofluoric acid water content of the pre-wash acid, and using the least squares method to minimize the sum of squares of the errors for the historical data and the laboratory data to determine the objective function for predicting the hydrofluoric acid water content of the pre-wash acid; Among them, the objective function of the water content prediction of pre-wash acid hydrofluoric acid is: <h2 style=";text-align:left;direction:ltr">Y<h2 style=";text-align:left;direction:ltr"> m <h2 style=";text-align:left;direction:ltr"> =ɑ0+ɑ1·p1+ɑ2·p2+ɑ3·f<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> ɑ4·T<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> ɑ5·T3·T3; Among them, Y m It indicates the predicted value of water content of pre-wash acid hydrofluoric acid; ɑ j (j=0, 1, 2, 3, 4, 5) is the regression coefficient; p1 is the total acid to fluorite ratio of 98% sulfuric acid and 105% sulfuric acid; p2 is a ratio of 98% sulfuric acid to 105% sulfuric acid.

2. The method according to claim 1, characterized in that The setting parameters of the hydrofluoric acid production process input by the operator in S1 include: Pre-wash acid moisture setting value Y sp , Mixed acid tank temperature setting value T sp 、The minimum value F of the constraint range of 98% sulfuric acid flow 1f _ min 、98% of the maximum value of the sulfuric acid flow constraint range F 1f _ max 、The minimum value F of the constraint range of 105% sulfuric acid flow 2f _ min , the maximum value F of the constraint range of 105% sulfuric acid flow 2f _ max .

3. The method according to claim 2, characterized in that in, The total acid to fluorite ratio p1 of 98% sulfuric acid and 105% sulfuric acid is calculated in advance by formula (1); Wherein, formula (1) is: ρ1 is the density of 98% sulfuric acid; ρ2 is the density of 105% sulfuric acid; ρ3 is the density of fluorite calcium fluoride.

4. The method according to claim 3, characterized in that in, The ratio p2 of 98% sulfuric acid to 105% sulfuric acid is calculated by formula (2); Wherein, formula (2) is:

5. The method according to claim 4, characterized in that S5 specifically includes: S51, based on the predicted value Y of the pre-wash acid hydrofluoric acid water content m The target value F1 of the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank are obtained by using the pre-set process setting objective function and the pre-wash acid water content setting, the mixed acid tank temperature setting and the constraint conditions input by the operator; The process setting objective function is: <h2 style=";text-align:left;direction:ltr">MIN(Y<h2 style=";text-align:left;direction:ltr"> m <h2 style=";text-align:left;direction:ltr"> (T3) + (F1, F2, Y)<h2 style=";text-align:left;direction:ltr"> sp <h2 style=";text-align:left;direction:ltr"> T<h2 style=";text-align:left;direction:ltr"> sp <h2 style=";text-align:left;direction:ltr"> ); F1 is the calculated target value for 98% sulfuric acid; F2 is the calculated target value for 105% sulfuric acid; f() is the model prediction algorithm MPC; S52, controlling the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank to be respectively the same as the target value F1 of the actual flow rate f1 of the 98% sulfuric acid entering the mixed acid tank and the target value F2 of the actual flow rate f2 of the 105% sulfuric acid entering the mixed acid tank, so as to adjust the pre-wash acid water content in the hydrofluoric acid production process.

6. The method according to claim 5, characterized in that The constraints include: -ε1 <Y m -AND sp <ε1; -e2 <T3-T sp <ε2; P 1p _ min <p1<P 1p _ max ; F 1f _ min <f1<F 1f _ max ; F 2f _ min <f2<F 2f _ max ; Where: ε1 is the first preset value; ε2 is the second preset value; P 1p _ min is the minimum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid; 1p _ max It is the maximum value of the total acid to fluorite ratio p1 constraint range of 98% sulfuric acid and 105% sulfuric acid.

7. A pre-wash acid water content control system in hydrofluoric acid production, characterized in that: The system comprises: A receiving module, used for receiving setting parameters of a hydrofluoric acid production process input by an operator; The acquisition module is used to collect the variable parameters of the hydrofluoric acid production process read by the DCS; The variable parameters of the hydrofluoric acid production process read by the DCS include: the actual flow rate f1 of 98% sulfuric acid entering the mixed acid tank, the actual flow rate f2 of 105% sulfuric acid entering the mixed acid tank, the actual flow rate f3 of fluorite calcium fluoride entering the reactor in the hydrofluoric acid production process, the actual flow rate f4 of 98% sulfuric acid entering the absorption tower, and the temperature T3 of the mixed acid tank in the hydrofluoric acid production process; A prediction module, for obtaining a predicted value of the hydrofluoric acid water content of the pre-washing acid by using a preset objective function for predicting the hydrofluoric acid water content of the pre-washing acid based on the set parameters of the hydrofluoric acid production process input by the operator and the variable parameters of the hydrofluoric acid production process read by the DCS; The objective function is obtained by collecting the variable parameters of the hydrofluoric acid production process in the historical stage and the corresponding actual hydrofluoric acid water content of the pre-wash acid, and using the least squares method to minimize the sum of squares of errors for the historical data and laboratory data to determine the objective function for predicting the hydrofluoric acid water content of the pre-wash acid; Among them, the objective function of the water content prediction of pre-wash acid hydrofluoric acid is: <h2 style=";text-align:left;direction:ltr">Y<h2 style=";text-align:left;direction:ltr"> m <h2 style=";text-align:left;direction:ltr"> =ɑ0+ɑ1·p1+ɑ2·p2+ɑ3·f<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> ɑ4·T<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> ɑ5·T3·T3; Among them, Y m It indicates the predicted value of water content of pre-wash acid hydrofluoric acid; ɑ j (j=0, 1, 2, 3, 4, 5) is the regression coefficient; p1 is the total acid to fluorite ratio of 98% sulfuric acid and 105% sulfuric acid; p2 is the ratio of 98% sulfuric acid to 105% sulfuric acid; A constraint module, used for receiving the pre-wash acid moisture set value, the mixed acid tank temperature set value and constraint conditions input by the operator; The control module is used to adjust the pre-wash acid water content in the hydrofluoric acid production process based on the predicted value of the pre-wash acid hydrofluoric acid water content and the pre-wash acid water content setting value, the mixed acid tank temperature setting value and the constraint conditions input by the operator.

8. The system according to claim 7, characterized in that The system further comprises: The prompt module is used to output information to remind the operator to adjust the constraints when the constraints cannot be met.

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