An automatic control system for ammonium chloride crystal particles

Abstract

The invention discloses an automatic control system for ammonium chloride crystal particles, and relates to the technical field of ammonium chloride production. The system is composed of a crystallizer unit, a sensor unit, an actuator unit, a controller unit, and a data storage and analysis unit. The automatic control system for ammonium chloride crystal particles of the invention significantly improves the quality of ammonium chloride crystal particles through the coordinated work of a multi-stage crystallizer and the precise coordination between the units. In a primary crystallizer, the conditions for forming crystal nuclei can be accurately controlled to ensure the stability of the number and quality of crystal nuclei. In an intermediate crystallizer stage, the optimized temperature, additive and stirring control strategies promote the uniform growth of crystals and effectively improve the crystal morphology. In a final crystallizer, the high consistency of product particle size is ensured by means of precise particle size screening and environmental control. Through the multi-stage precise control, the particle size distribution of ammonium chloride crystals is more concentrated, and the purity of the product is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ammonium chloride production, and in particular relates to an automatic control system for ammonium chloride crystal particles. Background Art

[0002] In the field of chemical production, ammonium chloride is an important basic chemical raw material, widely used in agriculture, medicine, textile and other industries. The characteristics of its crystal particles, such as purity, particle size distribution, crystal morphology, etc., are directly related to the quality and application performance of the product. Therefore, it is of great economic value and market demand to achieve precise control of the ammonium chloride crystallization process and produce high-quality ammonium chloride crystal products.

[0003] However, the traditional ammonium chloride crystallization process lacks the means of fine control over the crystallization process in terms of controlling the crystal particles, and cannot automatically adjust the working state according to the different stages of crystallization. In terms of temperature control, it can often only be roughly adjusted, and it is difficult to meet the temperature accuracy requirements of each stage in the multi-stage crystallization process, resulting in uneven crystal growth and a wide particle size distribution. At the same time, the addition of additives is also a fixed dose, and it cannot be dynamically optimized according to the crystal growth conditions in real time, which affects the crystallization effect and product quality. Moreover, the connection between different crystallization stages of the traditional process is not smart enough, and the adjustment of material transmission and equipment operating parameters lacks coordination, which easily leads to energy waste and low production efficiency. Summary of the invention

[0004] The purpose of the present invention is to make up for the deficiencies of the prior art and provide an automatic control system for ammonium chloride crystal particles. The system realizes the refined management of the crystallization process through the coordinated work and precise control of a multi-stage crystallizer, improves product quality, and enhances its competitiveness in the market. At the same time, the precise control strategy reduces production energy consumption, reduces refrigeration capacity and steam consumption by optimizing the crystallization conditions at each stage, and promotes efficient utilization of resources.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] An automatic control system for ammonium chloride crystal particles, the system is composed of a crystallizer unit, a sensor unit, an actuator unit, a controller unit and a data storage and analysis unit;

[0007] The crystallizer unit is composed of a multi-stage crystallizer, including a primary crystallizer, an intermediate crystallizer and a final crystallizer, and the crystallizers at each stage are connected in sequence to realize the sequential flow of materials, wherein the primary crystallizer is equipped with a stirring device for preliminary formation of crystal nuclei, the intermediate crystallizer is provided with a guide plate to guide the flow direction of the material for preliminary growth and regularization of the crystal shape, and the final crystallizer is equipped with a high-precision particle size screening device to screen the crystal particles in real time to ensure the particle size consistency of the final product;

[0008] The sensor unit is equipped with a temperature sensor, a liquid level sensor and a particle size sensor in each level of the crystallizer. The temperature sensor is used to accurately measure the temperature change during the crystallization process, the liquid level sensor is used to monitor the liquid level in the crystallizer, and the particle size sensor is used to dynamically detect the particle size of the ammonium chloride crystal particles. The sensor unit collects the temperature, liquid level and particle size parameters in each level of the crystallizer in real time and transmits the data to the controller unit;

[0009] The actuator unit includes a coolant flow regulating valve, an additive adding pump, an agitator speed regulating device, and a material conveying pump and valve. The coolant flow regulating valve adjusts the coolant flow of each level of crystallizer according to the controller instruction, the additive adding pump accurately adds additives to each level of crystallizer, the agitator speed regulating device adjusts the agitator speed in each level of crystallizer, and the material conveying pump and valve control the conveying of materials between each level of crystallizer. The actuator unit performs corresponding operations based on the parameters collected by the sensor according to the instructions of the controller unit.

[0010] The controller unit receives the data transmitted by the sensor unit, generates control instructions according to the control algorithm, accurately controls the entire crystallization system, coordinates the working state of each level of crystallizer, the action of the actuator unit and the interaction with other units, and the control algorithm includes:

[0011] Temperature control: For the target temperature T target , the actual temperature is T actual , the coolant flow adjustment coefficient is k t , then the opening adjustment amount of the coolant flow control valve ΔV t The calculation formula is ΔV t =k t (T actual -T target );

[0012] Additive control: For target particle size D target The actual particle size is D actual , the additive amount adjustment coefficient is k d , then the flow adjustment of the additive pump ΔV d The calculation formula is ΔV d =k d (Dtarget -D actual );

[0013] Agitator speed control: In the early stage of crystallization, for the initial speed N0, the liquid level height H, and the liquid level influence coefficient k h1 , then the formula for calculating the agitator speed N1 is N1=N0+k h1 (H-H0), where H0 is the initial liquid level. During the crystallization process, the speed reduction factor is k h2 , the crystallization progress is P, then the agitator speed N2 calculation formula is N2 = N1-k h2 P;

[0014] The data storage and analysis unit is connected to the controller unit, and stores sensor data, system operating parameters and historical control records during the operation of each level of crystallizer in real time. By conducting in-depth analysis of the data, data support is provided for system optimization and intelligent control, and the analysis results are fed back to the controller unit to achieve automatic optimization and real-time adjustment of the system.

[0015] Furthermore, in the primary crystallizer process, the control algorithm of the controller unit controls the temperature, and for the primary crystallizer target temperature T p-target , the allowable temperature fluctuation range is ±ΔT p The actual temperature collected by the temperature sensor in real time is T p-actual , for T p-actual >T p-target +ΔT p When the coolant flow rate adjustment coefficient is k tp1 , then the opening of the coolant flow control valve increases by ΔV tp1 The calculation formula is ΔV tp1 =k tp1 (T p-actual -(T p-target +ΔT p )), for T p-actual <T p-target -ΔT p When the coolant flow rate adjustment coefficient is k tp2 , then the opening of the coolant flow control valve decreases by ΔV tp2 The calculation formula is ΔV t p2=k tp2 ((T p-target -ΔT p )-T p-actual ), and at the same time, the relationship between the reaction heat release rate and time in the primary crystallizer, that is, the reaction heat release rate q r The function that changes with time t is q r=a1t+b1, where a1 and b1 are thermal reaction coefficients, which dynamically compensate the coolant flow, and the compensation coefficient is k c1 , then the compensated coolant flow adjustment ΔV tc1 =ΔV tc1 =k c1 (a1t+b1), the final adjustment amount of the coolant flow control valve is ΔV t-p =ΔV tp1 +ΔV tp2 +ΔV tc1 ;

[0016] In terms of additive control, for the primary crystallizer, the target nucleus number density is n p-target , the actual nucleus number density through the particle size sensor data is n p-actual , the additive amount adjustment coefficient is k dp1 , then the flow adjustment of the additive pump ΔV dp1 The calculation formula is ΔV dp1 =k dp1 (n p-target -np-actual), in addition, the relationship between the crystal nucleation rate and the temperature and stirring intensity, that is, the crystal nucleation rate r n The relationship between temperature T and stirring speed is r n =c1T 2 +d1N+e1, where c1, d1 and e1 are the crystal nucleation reaction coefficients. The amount of additive added is corrected according to the current temperature and mixing speed, that is, the correction coefficient is k m1 , then the corrected additive amount adjustment amount ΔV dm1 for The final adjustment of the additive pump is ΔV d-p =ΔV dp1 +ΔV dm1 .

[0017] Furthermore, in the primary crystallizer process, the control algorithm of the controller unit is in the stirring control aspect, and the initial stirring speed of the primary crystallizer is N p0 , the crystal nucleus formation stirring intensity coefficient is k s1 , according to the nucleation rate r n Calculate the expected stirring speed N p-expect , the calculation formula is N p-expect =N p0 +k s1 r n.o When the actual stirring speed is adjusted, the speed adjustment step is ΔN p , when N p-expect -N p-actual >ΔN p Each time the stirring speed is increased by ΔNp , when N p-expect -N p-actual <-ΔN p When the stirring speed is reduced by ΔN each time p , until |N p-expect -N p-actual |≤ΔN p ;

[0018] In terms of material delivery control, the judgment threshold for completion of nucleation in the primary crystallizer is n p-threshold , for the crystal nucleus number density n obtained through the particle size sensor data p-actual ≥n p-threshold When the material is delivered to the intermediate crystallizer, the controller unit starts the material delivery pump to deliver the primary crystal product to the intermediate crystallizer. At the same time, according to the liquid level height H monitored by the liquid level sensor, p-actual , adjust the flow rate Q of the material delivery pump p-transfer , the level-flow ratio coefficient is k q1 , then Q p-transfer =k q1 H p-actual , so that the material can be transported to the intermediate crystallizer smoothly and in appropriate amounts.

[0019] Furthermore, in the process of the intermediate crystallizer, the control algorithm of the controller unit controls the temperature, and the target temperature of the intermediate crystallizer is T m-target , the allowable temperature fluctuation range is ±ΔT m The actual temperature collected by the temperature sensor in real time is T m-actual , when T m-actual >T m-target +ΔT m When the coolant flow rate adjustment coefficient is k tm1 , then the opening of the coolant flow control valve increases by ΔV tm1 The calculation formula is ΔV tm1 =k tm1 (T m-actual -(T m-target +ΔT m )), when T m-actual <T m-target -ΔT m When the coolant flow rate adjustment coefficient is k tm2 , then the opening of the coolant flow control valve decreases by ΔV tm2 The calculation formula is ΔV t m2=k tm2 ((T m-target -ΔT m )-T m-actual ), using the relationship between the crystallization heat release rate in the intermediate crystallizer and the crystal growth progress, that is, the crystallization heat release rate q cAs the crystal growth progresses P m The function of change is Among them, a2, b2 and c2 are the crystallization heat release coefficients, and the coolant flow rate is dynamically compensated. The compensation coefficient is k c2 , then the compensated coolant flow adjustment ΔV tc2 for The final adjustment amount of the coolant flow control valve is ΔV t-m =ΔV tm1 +ΔV tm2 +ΔV tc2 ;

[0020] In terms of additive control, the target crystal growth rate of the intermediate crystallizer is V m-target , the actual crystal growth rate through the particle size sensor data is v m-actual , the additive amount adjustment coefficient is k dm2 , then the flow adjustment of the additive pump ΔV dm2 The calculation formula is ΔV dm2 =k dm2 (v m-target -v m-actual ), using the relationship between crystal growth rate and temperature, stirring intensity and additive concentration, that is, the crystal growth rate v g The relationship between temperature T, stirring speed N and additive concentration C is v g =d2T 3 +e2N 2 +f2C+g2, where d2, e2, f2 and g2 are adjustment coefficients. The amount of additive added is corrected according to the current temperature, stirring speed and additive concentration. The correction coefficient is k m2 , then the corrected additive amount adjustment amount ΔV dm3 for The final adjustment of the additive pump is ΔV d-m =ΔV dm2 +ΔV dm3 .

[0021] Furthermore, in the intermediate crystallizer process, the control algorithm of the controller unit is in the stirring control aspect, and the initial stirring speed of the intermediate crystallizer is N m0 , the crystal growth stirring intensity coefficient is k s2 , according to the crystal growth rate v g Calculate the expected stirring speed N m -expect, calculated as N m -expect=N m0 +k s2 v g When the actual stirring speed is adjusted, the speed adjustment step is ΔNm , when N m-expect -N m-actual >ΔN m Each time the stirring speed is increased by ΔN m , when N m-expect -N m-actual <-ΔN m When the stirring speed is reduced by ΔN each time m , until |N m-expect -N m-actual |≤ΔN m .

[0022] In terms of material circulation control, the minimum particle size for qualified crystal growth in the intermediate crystallizer is D m-min , the maximum particle size is D m-max , the crystal size is monitored in real time by the particle size sensor. m-actual <D m-min Keep the material circulating in the intermediate crystallizer. m-actual >D m-max When the material circulation pump is started, the material returns to the intermediate crystallizer to continue growing. The flow rate of the circulation pump is Q m-recycle According to the particle size deviation ΔD m =D m-actual -D m-max Adjust the circulation flow ratio coefficient to kr1, then Q m-recvcle =k r1 ΔD m , so that the crystals grow evenly.

[0023] Furthermore, in the final crystallizer process, the control algorithm of the controller unit controls the temperature, and the final crystallizer target temperature is T f-target , the temperature fluctuation range is ±ΔT f The actual temperature collected by the temperature sensor in real time is T f-actual , when T f-actual >T f-target +ΔT f When the coolant flow rate adjustment coefficient is k tf1 , then the opening of the coolant flow control valve increases by ΔV tf1 The calculation formula is ΔV tf1 =k tf1 (T f-actual -(T f-target +ΔT f )), when T f-actual <T f-target -ΔT f When the coolant flow rate adjustment coefficient is k tf2 , then the opening of the coolant flow control valve decreases by ΔV tf2 The calculation formula is ΔVt f2=k tf2 ((T f-target -ΔT f )-T f-actual ), according to the crystal growth state function S f =h1P f +i1,P f is the final crystal growth progress in the crystallizer, h1 and i1 are growth adjustment coefficients, and the coolant flow rate is fine-tuned, and the fine-tuning coefficient is k c3 , then the coolant flow adjustment amount after fine-tuning ΔV tc3 =ΔV tc3 =k c3 S f , the final adjustment amount of the coolant flow control valve is ΔV t-f =ΔV tf1 +ΔV tf2 +ΔV tc3 ;

[0024] In terms of additive control, the final crystallizer target product particle size distribution uniformity index is U f-target The actual uniformity index calculated by the particle size sensor data is U f-actual , the additive amount adjustment coefficient is k df1 , then the flow adjustment of the additive pump ΔV df1 The calculation formula is ΔV df1 =k df1 (U f-target -U f-actual ), at the same time, the additive modifies the crystal surface and removes impurities in the final crystallization stage, and the additive effect function is E f =j1C f +k1, where C f is the final additive concentration in the crystallizer, j1 and k1 are additive adjustment coefficients, and the additive amount is corrected according to the current additive concentration. Assume that the correction coefficient is k m3 , then the corrected additive amount adjustment amount ΔV df2 =ΔV df2 =k m3 E f , the final adjustment amount of the additive adding pump is ΔV d-f =ΔV df1 +ΔV df2 .

[0025] Furthermore, in the final crystallizer process, the control algorithm of the controller unit is in the stirring control aspect, and the initial stirring speed of the final crystallizer is N f0 , the final product quality stirring intensity coefficient is k s3 , according to the crystal growth state Sf Calculate the expected stirring speed N f -expect, calculated as N f -expect=N f0 +k s3 S f When the actual stirring speed is adjusted, the speed adjustment step is ΔN f , when N f-expect -N f-actual >ΔN f Each time the stirring speed is increased by ΔN f , when N f-expect -N f-actual <-ΔN f When the stirring speed is reduced by ΔN each time f , until |N f-expect -N f-actual |≤ΔN f ;

[0026] In terms of discharge control, the minimum particle size of the final crystallizer product is D f-min , the maximum particle size is D f-max , the crystal size is monitored in real time by the particle size sensor. f-actual ≥D f-min And D f-actual ≤D f-max When D f-actual <D f-min and D f-actual >D f-max When the material returns to the intermediate crystallizer, the material return device is started to return the unqualified crystals to the intermediate crystallizer for continued growth.

[0027] Furthermore, the controller unit responds to the data collected by the sensor and generates precise control instructions according to the control algorithm, specifically including:

[0028] Primary crystallization stage: The controller controls the temperature and additive concentration in the primary crystallizer by adjusting the coolant flow regulating valve and the additive adding pump according to the primary crystallization temperature and concentration. At the same time, the agitator speed regulating device is started to promote rapid mixing of materials to form uniform crystal nuclei. The temperature, liquid level and particle size changes in the primary crystallizer are continuously monitored. According to the data of the liquid level sensor, the material delivery pump is started to deliver the primary crystal product to the intermediate crystallizer.

[0029] Intermediate crystallization stage: The controller adjusts the coolant flow rate and additive addition amount according to the target temperature and concentration of the intermediate crystallizer, and reduces the agitator speed at the same time. Based on the feedback from the particle size sensor, the material circulation pump returns the crystals that have not yet reached the standard to the intermediate crystallizer for continued growth, so that the crystal size distribution is uniform;

[0030] Final crystallization stage: control the temperature in the final crystallizer, adjust the coolant flow and additive addition, further reduce the agitator speed, use the particle size screening device in the final crystallizer to monitor the discharge particle size in real time, and return particles that do not meet the size requirements to the intermediate crystallizer for continued growth.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The automatic control system for ammonium chloride crystal particles of the present invention significantly improves the quality of ammonium chloride crystal particles through the coordinated work of multi-stage crystallizers and the precise coordination between various units. In the primary crystallizer, the conditions for crystal nucleus formation can be accurately controlled to ensure the stability of the number and quality of crystal nuclei. In the intermediate crystallizer stage, the optimized temperature, additive and stirring control strategies promote the uniform growth of crystals and effectively improve the crystal morphology. The final crystallizer ensures the high consistency of product particle size by means of precise particle size screening and environmental control. Through this multi-stage precise control, the particle size distribution of ammonium chloride crystals is more concentrated, the product purity is improved, and the impurity content is reduced, thereby improving the market competitiveness of the product and meeting the growing market demand for high-quality ammonium chloride products.

[0033] (2) The intelligent coordination of the working states of the crystallizers at various levels and the precise movement of the actuators of the present invention greatly shorten the crystallization cycle and improve the output per unit time. The precise temperature control reduces unnecessary energy consumption, the optimized additive addition strategy reduces the waste of additives, and the efficient material transportation and circulation mechanism avoids the backlog and waste of materials. The automated operation of the system reduces manual intervention, reduces labor costs and losses caused by human operational errors, and promotes the ammonium chloride production industry to develop in the direction of high efficiency, energy saving and sustainability.

[0034] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a flow chart of an automatic control system for ammonium chloride crystal particles;

[0037] Figure 2 This is a structural diagram of the actuator unit in an automatic control system for ammonium chloride crystal particles. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] See also Figure 1 and Figure 2 As shown, this embodiment describes in detail the specific application process of this automatic control system for ammonium chloride crystal particles in an ammonium chloride production workshop. Through cold crystallization tests, the effects of various additives and their usage amounts on the particle size of ammonium chloride crystal particles and the crystallization temperature are studied, and a comprehensive inspection of the system is carried out to ensure that the connection between the crystallizer unit, sensor unit, actuator unit, controller unit, and data storage and analysis unit is stable and the signal transmission is normal.

[0040] In the specific implementation, first, for the crystallizer unit, confirm that the connecting pipes of the primary crystallizer, the intermediate crystallizer and the final crystallizer have no leakage, and the valves are opened and closed normally. According to the production requirements, the initial working parameters of each level of crystallizer are set in the controller unit, including the target temperature range of the primary crystallizer, the target temperature range of the intermediate crystallizer, and the target temperature range of the final crystallizer; set the target crystal nucleus number density of the primary crystallizer, the target crystal growth rate of the intermediate crystallizer, and the target product particle size distribution uniformity index of the final crystallizer; set the initial speed of the agitator in each level of crystallizer, and at the same time, set the initial working parameters of the actuator units such as the material delivery pump and the additive addition pump, start the system, and the raw material liquid enters the primary crystallizer. The temperature sensor monitors the temperature in the primary crystallizer in real time, and the initial actual temperature is T p-actual1 When T p-actual1 >T p-target +ΔT p (where T p -target is the target temperature of the primary crystallizer, ΔT p is the allowable temperature fluctuation range), according to the temperature control algorithm, the coolant flow adjustment coefficient is k tp1 , the opening increase of the coolant flow control valve ΔV tp1 =k tp1 (T p-actual1 -(T p-target +ΔT p )) to increase the coolant flow rate and reduce the temperature in the crystallizer; when T p-actual1 <Tp-target -ΔT p When the coolant flow rate adjustment coefficient is k tp2 , the opening of the coolant flow control valve decreases by ΔV tp2 =k tp2 ((T p-target -ΔT p )-T p-actual1 At the same time, considering the relationship between the reaction heat release rate and time in the primary crystallizer (assuming that the reaction heat release rate q r =a1t+b1, where a1 and b1 are coefficients determined based on experimental data), and the compensation coefficient is k c , the compensated coolant flow adjustment ΔV tc1 =k c1 (a1t+b1), the final adjustment amount of the coolant flow control valve is ΔV t-p =ΔV tp1 +ΔV tp2 +ΔV tc1 The liquid level sensor monitors the liquid level in the primary crystallizer. The liquid level is H p-actual1 According to the material delivery control algorithm, the controller unit is ready to start the material delivery pump and estimate the number density n of crystal nuclei in the primary crystallizer according to the particle size sensor. p-actual1 , when n p-actual1 <n p-target (where n p-target is the target nucleus density of the primary crystallizer), according to the additive control algorithm, the additive addition adjustment coefficient is k dp1 , flow adjustment of additive adding pump ΔV dp1 =k dp1 (n p-target -n p-actual1 ), and at the same time, considering the relationship between the crystal nucleation rate and the temperature and stirring intensity (the crystal nucleation rate r n =c1T 2 +d1N+e1, where c1, d1 and e1 are the crystal nucleus reaction coefficients), according to the current temperature T p-actual1 and stirring speed N p-actual1 , the correction factor is k m1 , the revised additive amount adjustment amount The final adjustment of the additive pump is ΔV d-p =ΔV dp1 +ΔV dm1 The agitator speed regulating device adjusts the agitator speed according to the agitation control algorithm. The initial agitation speed of the primary crystallizer is set to N p0 The desired nucleation stirring intensity coefficient is k s1 , according to the nucleation rate r n Calculate the expected stirring speed Np -expect1=N p0 +k s1 r n When the actual stirring speed is adjusted, the speed adjustment step is set to ΔN p , when N p-expect1 -N p-actual1 >ΔN p Each time the stirring speed is increased by ΔN p ; When N p-expect1 -N p-actual1 <-ΔN p When the stirring speed is reduced by ΔN each time p , until |N p-expect1 -N p-actual1 |≤ΔN p , when the nucleus number density n estimated by the particle size sensor data p-actual1 ≥n p-threshold (where n p-threshold When the liquid level height H is monitored by the liquid level sensor, the controller unit starts the material delivery pump to deliver the primary crystal product to the intermediate crystallizer. p-actual1 , adjust the flow rate Q of the material delivery pump p -transfer=k q1 H p-actual1 (where k q1 is the liquid level-flow ratio coefficient), ensuring that the material is transported to the intermediate crystallizer smoothly and in appropriate amounts.

[0041] Then, after the primary crystallization product enters the intermediate crystallizer, the temperature sensor continuously monitors the temperature, that is, the actual temperature monitored is T m-actual1 , when T m-actual1 >T m-target +ΔT m (where T m-target is the target temperature of the intermediate crystallizer, ΔT m is the allowable temperature fluctuation range), the coolant flow adjustment coefficient is k tm1 , the opening increase of the coolant flow control valve ΔV tm1 =k tm1 (T m-actual1 -(T m-target +ΔT m )); When T m-actual1 <T m-target -ΔT m When the coolant flow rate adjustment coefficient is k tm2 , the opening of the coolant flow control valve decreases by ΔV tm2 =k tm2 ((T m-target -ΔT m)-T m-actual1 ), considering the relationship between the crystallization heat release rate and the crystal growth progress in the intermediate crystallizer (crystallization heat release rate Where a2, b2 and c2 are the crystallization heat release coefficients, P m is the crystal growth progress), and the compensation coefficient is k c 2. Coolant flow adjustment after compensation The final adjustment amount of the coolant flow control valve is ΔV t-m =ΔV tm1 +ΔV tm2 +ΔV tc2 , the particle size sensor monitors the crystal size, and the actual crystal growth rate is v m-actual1 , when v m-actual1 <v m-target (where v m-target is the target crystal growth rate of the intermediate crystallizer), according to the additive control algorithm, the additive addition adjustment coefficient is k dm2 , flow adjustment of additive adding pump ΔV dm2 =k dm2 (v m-target -v m-actual1 ). At the same time, consider the relationship between crystal growth rate and temperature, stirring intensity and additive concentration (assuming that the crystal growth rate v g =d2T 3 +e2N 2 +f2C+g2, where d2, e2, f2 and g2 are adjustment coefficients, T is temperature, N is stirring speed, and C is additive concentration). m-actual1 , stirring speed N m -actual1 and additive concentration C m -actual1, correction factor is k m2 , the corrected additive amount adjustment amount The final adjustment of the additive pump is ΔV d -m=ΔV dm2 +ΔV dm3 The agitator speed regulating device adjusts the agitator speed according to the agitation control algorithm. The initial agitation speed of the intermediate crystallizer is set to N m0 , the desired crystal growth stirring intensity coefficient is k s2 , according to the crystal growth rate v g Calculate the expected stirring speed N m-expect1 =N m0 +k s2 v g When the actual stirring speed is adjusted, the speed adjustment step is ΔN m , when N m-expect1 -Nm-actual1 >ΔN m Each time the stirring speed is increased by ΔN m , when N m-expect1 -N m-actual1 <-ΔN m When the stirring speed is reduced by ΔN each time m , until |N m-expect1 -N m-actual1 |≤ΔN m , assuming that the minimum particle size of the crystal growth in the intermediate crystallizer is D m-min , the maximum particle size is D m-max , when the crystal size is D m-actual1 <D m-min When D m-actual1 >D m-max When the material circulation pump is started, part of the material is returned to the intermediate crystallizer for further growth. The flow rate of the circulation pump is Q m-recycle According to the particle size deviation ΔD m =D m-actual1 -D m-max Adjust the circulation flow ratio coefficient to k r1 , then Q m-recycle =k r1 ΔD m Ensure uniform crystal growth.

[0042] Afterwards, the material after being processed in the intermediate crystallizer enters the final crystallizer, and the temperature sensor continuously monitors the temperature, and the actual temperature is T f-actual1 , when T f-actual1 >T f-target +ΔT f (where T f-target is the final crystallizer target temperature, ΔT f is the allowable temperature fluctuation range), the coolant flow adjustment coefficient is k tf1 , the opening increase of the coolant flow control valve ΔV tf1 =k tf1 (T f-actual1 -(T f-target +ΔT f )); When T f-actual1 <T f-target -ΔT f When the coolant flow rate adjustment coefficient is k tf2 , the opening of the coolant flow control valve decreases by ΔV tf2 =k tf2( (T f-target -ΔT f )-T f-actual1), considering that the crystallization process in the final crystallizer is nearing the end, according to the crystal growth state (assuming that the crystal growth state function is S f =h1P f +i1, where P f is the final crystal growth progress in the crystallizer, h1 and i1 are growth adjustment coefficients) to fine-tune the coolant flow rate, and the fine-tuning coefficient is k c3 , the coolant flow adjustment amount after fine-tuning ΔV tc3 =k c3 S f , the final adjustment amount of the coolant flow control valve is ΔV t-f =ΔV tf1 +ΔV tf2 +ΔV tc3 The particle size sensor monitors the crystal particle size and calculates the actual product particle size distribution uniformity index as U f-actual1 , when U f-actual1 <U f-target (Where U f -target is the final crystallizer target product particle size distribution uniformity index), according to the additive control algorithm, the additive addition adjustment coefficient is k df1 , flow adjustment of additive adding pump ΔV df1 =k df1 (U f-target -U f-actual1 ), and at the same time, consider the effect of additives on crystal surface modification and impurity removal in the final crystallization stage (assuming that the additive effect function is E f =j1C f +k1, where C f is the final additive concentration in the crystallizer, j1 and k1 are additive adjustment coefficients), according to the current additive concentration C f-actual1 Correct the amount of additives added, the correction factor is k m3 , the corrected additive amount adjustment ΔV df2 =k m3 E f , the final adjustment amount of the additive adding pump is ΔV d-f =ΔV df1 +ΔV df2 The agitator speed regulating device adjusts the agitator speed according to the agitation control algorithm. The initial agitation speed of the final crystallizer is set to N f0 , the desired final product quality stirring intensity coefficient is k s3 , according to the crystal growth state S f Calculate the expected stirring speed N f-expect1 =N f0 +k s3 S f When the actual stirring speed is adjusted, the speed adjustment step is set to ΔNf , when N f-expect1 -N f-actual1 >ΔN f Each time the stirring speed is increased by ΔN f ; When N f-expect1 -N f-actual1 <-ΔN f When the stirring speed is reduced by ΔN each time f , until |N f-expect1 -N f-actual1 |≤ΔN f , assuming that the minimum particle size of the final crystallizer product is D f-min , the maximum particle size is D f-max , when the crystal size D f-actual1 ≥D f-min And D f-actual1 ≤D f-max When D f-actual1 <D f-min or D f-actual1 >D f-max When the material return device is started, the unqualified crystals are returned to the intermediate crystallizer for further growth. The flow rate of the return device is Q f-return According to the particle size deviation ΔD f =D f-actual1 -D f-min (When D f -actual1<D f-min ) or ΔD f =D f-actual1 -D f-max (When D f -actual1>D f-max When the return flow ratio coefficient is kr2, Q f -return=k r2 ΔD f , ensuring the quality of the final product.

[0043] Finally, during the entire crystallization process, the sensor unit continuously collects parameters such as temperature, liquid level and particle size in each level of crystallizer, and transmits the data to the controller unit. The controller unit adjusts the actuator unit in real time according to the preset algorithm, and stores the data in the data storage and analysis unit. The data storage and analysis unit regularly conducts in-depth analysis of the stored data, and continuously optimizes and adjusts the coefficients in the control algorithm by mining historical data to improve the system's control accuracy over the crystallization process. The analysis results are fed back to the controller unit to achieve automatic optimization and real-time adjustment of the system, ensuring that the system is always in the best operating state and stably produces high-quality ammonium chloride crystal particle products.

[0044] In summary, this embodiment automatically coordinates the working status of crystallizers at all levels according to the crystallization process, reduces the uncertainty caused by manual intervention, shortens the crystallization cycle, improves production efficiency, and accurately transmits and intelligently circulates materials between crystallizers at all levels, avoiding unnecessary stays and waste, ensuring that the system is always in the best operating state, helping enterprises to achieve long-term stable production and meet the market's continued demand for ammonium chloride products.

[0045] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An automatic control system for ammonium chloride crystal particles, characterized in that: The system consists of a crystallizer unit, a sensor unit, an actuator unit, a controller unit, and a data storage and analysis unit; The crystallizer unit is composed of a multi-stage crystallizer, including a primary crystallizer, an intermediate crystallizer and a final crystallizer, and the crystallizers at each stage are connected in sequence to realize the sequential flow of materials, wherein the primary crystallizer is equipped with a stirring device for preliminary formation of crystal nuclei, the intermediate crystallizer is provided with a guide plate to guide the flow direction of the material for preliminary growth and regularization of the crystal shape, and the final crystallizer is equipped with a high-precision particle size screening device to screen the crystal particles in real time to ensure the particle size consistency of the final product; The sensor unit is equipped with a temperature sensor, a liquid level sensor and a particle size sensor in each level of the crystallizer. The temperature sensor is used to accurately measure the temperature change during the crystallization process, the liquid level sensor is used to monitor the liquid level in the crystallizer, and the particle size sensor is used to dynamically detect the particle size of the ammonium chloride crystal particles. The sensor unit collects the temperature, liquid level and particle size parameters in each level of the crystallizer in real time and transmits the data to the controller unit; The actuator unit includes a coolant flow regulating valve, an additive adding pump, an agitator speed regulating device, and a material conveying pump and valve. The coolant flow regulating valve adjusts the coolant flow of each level of crystallizer according to the controller instruction, the additive adding pump accurately adds additives to each level of crystallizer, the agitator speed regulating device adjusts the agitator speed in each level of crystallizer, and the material conveying pump and valve control the conveying of materials between each level of crystallizer. The actuator unit performs corresponding operations based on the parameters collected by the sensor according to the instructions of the controller unit. The controller unit receives the data transmitted by the sensor unit, generates control instructions according to the control algorithm, accurately controls the entire crystallization system, coordinates the working state of each level of crystallizer, the action of the actuator unit and the interaction with other units, and the control algorithm includes: Temperature control: For the target temperature T target , the actual temperature is T actual , the coolant flow regulation coefficient is k t , then the opening adjustment amount of the coolant flow control valve ΔV t The calculation formula is ΔV t =k t (T actual -T target ); Additive control: For target particle size D target The actual particle size is D actual , the additive amount adjustment coefficient is k d , then the flow adjustment of the additive pump ΔV d The calculation formula is ΔV d =k d (D target -D actual ); Agitator speed control: In the early stage of crystallization, for the initial speed N0, the liquid level height H, and the liquid level influence coefficient k h1 , then the formula for calculating the agitator speed N1 is N1=N0+k h1 (H-H0), where H0 is the initial liquid level. During the crystallization process, the speed reduction factor is k h2 , the crystallization progress is P, then the agitator speed N2 calculation formula is N2 = N1-k h2 P; The data storage and analysis unit is connected to the controller unit, and stores sensor data, system operating parameters and historical control records during the operation of each level of crystallizer in real time. By conducting in-depth analysis of the data, data support is provided for system optimization and intelligent control, and the analysis results are fed back to the controller unit to achieve automatic optimization and real-time adjustment of the system.

2. A kind of ammonium chloride crystal particle automatic control system according to claim 1, characterized in that, In the primary crystallizer process, the control algorithm of the controller unit is in terms of temperature control. For the primary crystallizer target temperature T p-target , the allowable temperature fluctuation range is ±ΔT p The actual temperature collected by the temperature sensor in real time is T p-actual , for T p-actual >T p-target +ΔT p When the coolant flow rate adjustment coefficient is k tp1 , then the opening of the coolant flow control valve increases by ΔV tp1 The calculation formula is ΔV tp1 =k tp1 (T p-actual -(T p-target +ΔT p )), for T p-actual <T p-target -ΔT p When the coolant flow rate adjustment coefficient is k tp2 , then the opening of the coolant flow control valve decreases by ΔV tp2 The calculation formula is ΔV t p2=k tp2 ((T p-target -ΔT p )-T p-actual ), and at the same time, the relationship between the reaction heat release rate and time in the primary crystallizer, that is, the reaction heat release rate q r The function that changes with time t is q r =a1t+b1, where a1 and b1 are thermal reaction coefficients, which dynamically compensate the coolant flow, and the compensation coefficient is k c1 , then the compensated coolant flow adjustment ΔV tc1 =ΔV tc1 =k c1 ( a1t+b1 ) , the final adjustment amount of the coolant flow control valve is ΔV t-p =ΔV tp1 +ΔV tp2 +ΔV tc1 ; In terms of additive control, for the primary crystallizer, the target nucleus number density is n p-target , the actual nucleus number density through the particle size sensor data is n p-actual , the additive amount adjustment coefficient is k dp1 , then the flow adjustment of the additive pump ΔV dp1 The calculation formula is ΔV dp1 =k dp1 (n p-target -n p-actual ), in addition, the relationship between the crystal nucleation rate and the temperature and stirring intensity is used, that is, the crystal nucleation rate r n The relationship between temperature T and stirring speed is r n =c1T 2 +d1N+e1, where c1, d1 and e1 are the crystal nucleation reaction coefficients. The amount of additive added is corrected according to the current temperature and mixing speed, that is, the correction coefficient is k m1 , then the corrected additive amount adjustment amount ΔV dm1 for The final adjustment of the additive pump is ΔV d-p =ΔV dp1 +ΔV dm1 .

3. An automatic control system for ammonium chloride crystal particles according to claim 1, characterized in that: In the primary crystallizer process, the control algorithm of the controller unit is in the stirring control aspect, and the initial stirring speed of the primary crystallizer is N p0 , the crystal nucleus formation stirring intensity coefficient is k s1 , according to the nucleation rate r n Calculate the expected stirring speed N p-expect , the calculation formula is N p-expect =N p0 +k s1 r n.o When the actual stirring speed is adjusted, the speed adjustment step is ΔN p , when N p-expect -N p-actual >ΔN p Each time the stirring speed is increased by ΔN p , when N p-expect -N p-actual <-ΔN p When the stirring speed is reduced by ΔN each time p , until |N p-expect -N p-actual |≤ΔN p ; In terms of material delivery control, the judgment threshold for completion of nucleation in the primary crystallizer is n p-threshold , for the crystal nucleus number density n obtained through the particle size sensor data p-actual ≥n p-threshold When the material is delivered to the intermediate crystallizer, the controller unit starts the material delivery pump to deliver the primary crystal product to the intermediate crystallizer. At the same time, according to the liquid level height H monitored by the liquid level sensor, p-actual , adjust the flow rate Q of the material delivery pump p-transfer , the level-flow ratio coefficient is k q1 , then Q p-transfer =k q1 H p-actual , so that the material can be transported to the intermediate crystallizer smoothly and in appropriate amounts.

4. An automatic control system for ammonium chloride crystal particles according to claim 1, characterized in that: In the intermediate crystallizer process, the control algorithm of the controller unit is in temperature control, and the target temperature of the intermediate crystallizer is T m-target , the allowable temperature fluctuation range is ±ΔT m The actual temperature collected by the temperature sensor in real time is T m-actual , when T m-actual >T m-target +ΔT m When the coolant flow rate adjustment coefficient is k tm1 , then the opening of the coolant flow control valve increases by ΔV tm1 The calculation formula is ΔV tm1 =k tm1( T m-actual -(T m-target +ΔT m )), when T m-actual <T m-target -ΔT m When the coolant flow rate adjustment coefficient is k tm2 , then the opening of the coolant flow control valve decreases by ΔV tm2 The calculation formula is ΔV t m2=k tm2 ((T m-target -ΔT m )-T m-actual ), using the relationship between the crystallization heat release rate in the intermediate crystallizer and the crystal growth progress, that is, the crystallization heat release rate q c As the crystal growth progresses P m The function of change is Among them, a2, b2 and c2 are the crystallization heat release coefficients, and the coolant flow rate is dynamically compensated. The compensation coefficient is k c2 , then the compensated coolant flow adjustment ΔV tc2 for The final adjustment amount of the coolant flow control valve is ΔV t-m =ΔV tm1 +ΔV tm2 +ΔV tc2 ; In terms of additive control, the target crystal growth rate of the intermediate crystallizer is v m-target , the actual crystal growth rate through the particle size sensor data is v m-actual , the additive amount adjustment coefficient is k dm2 , then the flow adjustment of the additive pump ΔV dm2 The calculation formula is ΔV dm2 =k dm2 ( v m-target -v m-actual ), using the relationship between crystal growth rate and temperature, stirring intensity and additive concentration, that is, the crystal growth rate v g The relationship between temperature T, stirring speed N and additive concentration C is v g =d2T 3 +e2N 2 +f2C+g2, where d2, e2, f2 and g2 are adjustment coefficients. The amount of additive added is corrected according to the current temperature, stirring speed and additive concentration. The correction coefficient is k m2 , then the corrected additive amount adjustment amount ΔV dm3 for The final adjustment of the additive pump is ΔV d-m =ΔV dm2 +ΔV dm3 .

5. An automatic control system for ammonium chloride crystal particles according to claim 1, characterized in that: In the intermediate crystallizer process, the control algorithm of the controller unit is in the stirring control aspect, and the initial stirring speed of the intermediate crystallizer is N m0 , the crystal growth stirring intensity coefficient is k s2 , according to the crystal growth rate v g Calculate the expected stirring speed N m -expect, calculated as N m -expect=N m0 +k s2 v g When the actual stirring speed is adjusted, the speed adjustment step is ΔN m , when N m-expect -N m-actual >ΔN m Each time the stirring speed is increased by ΔN m , when N m-expect -N m-actual <-ΔN m When the stirring speed is reduced by ΔN each time m , until |N m-expect -N m-actual |≤ΔN m . In terms of material circulation control, the minimum particle size for qualified crystal growth in the intermediate crystallizer is D m-min , the maximum particle size is D m-max , the crystal size is monitored in real time by the particle size sensor. m-actual <D m-min Keep the material circulating in the intermediate crystallizer. m-actual >D m-max When the material circulation pump is started, the material returns to the intermediate crystallizer to continue growing. The flow rate of the circulation pump is Q m-recycle According to the particle size deviation ΔD m =D m-actual -D m-max Adjust the circulation flow ratio coefficient to k r1 , then Q m-recycle =k r1 ΔD m , so that the crystals grow evenly.

6. An automatic control system for ammonium chloride crystal particles according to claim 1, characterized in that: In the final crystallizer process, the control algorithm of the controller unit controls the temperature, and the final crystallizer target temperature is T f-target , the temperature fluctuation range is ±ΔT f The actual temperature collected by the temperature sensor in real time is T f-actual , when T f-actual >T f-target +ΔT f When the coolant flow rate adjustment coefficient is k tf1 , then the opening of the coolant flow control valve increases by ΔV tf1 The calculation formula is ΔV tf1 =k tf1 (T f-actual - ( T f-target +ΔT f )), when T f-actual <T f-target -ΔT f When the coolant flow rate adjustment coefficient is k tf2 , then the opening of the coolant flow control valve decreases by ΔV tf2 The calculation formula is ΔV t f2=k tf2 ((T f-target -ΔT f )-T f-actual ), according to the crystal growth state function S f =h1P f +i1,P f is the final crystal growth progress in the crystallizer, h1 and i1 are growth adjustment coefficients, and the coolant flow rate is fine-tuned, and the fine-tuning coefficient is k c3 , then the fine-tuned coolant flow adjustment amount ΔV tc3 =ΔV tc3 =k c3 S f , the final adjustment amount of the coolant flow control valve is ΔV t-f =ΔV tf1 +ΔV tf2 +ΔV tc3 ; In terms of additive control, the final crystallizer target product particle size distribution uniformity index is U f-target The actual uniformity index calculated by the particle size sensor data is U f-actual , the additive amount adjustment coefficient is k df1 , then the flow adjustment of the additive pump ΔV df1 The calculation formula is ΔV df1 =k df1 (U f-target -U f-actual ), at the same time, the additive modifies the crystal surface and removes impurities in the final crystallization stage, and the additive effect function is E f =j1C f +k1, where C f is the final additive concentration in the crystallizer, j1 and k1 are additive adjustment coefficients, and the additive amount is corrected according to the current additive concentration. The correction coefficient is k m3 , then the corrected additive amount adjustment amount ΔV df2 =ΔV df2 =k m3 E f , the final adjustment amount of the additive adding pump is ΔV d-f =ΔV df1 +ΔV df2 .

7. An automatic control system for ammonium chloride crystal particles according to claim 1, characterized in that: In the final crystallizer process, the control algorithm of the controller unit is in the stirring control aspect, and the initial stirring speed of the final crystallizer is N f0 , the final product quality stirring intensity coefficient is k s3 , according to the crystal growth state S f Calculate the expected stirring speed N f -expect, calculated as N f -expect=N f0 +k s3 S f When the actual stirring speed is adjusted, the speed adjustment step is ΔN f , when N f-expect -N f-actual >ΔN f Each time the stirring speed is increased by ΔN f , when N f-expect -N f-actual <-ΔN f When the stirring speed is reduced by ΔN each time f , until N f-expect -N f-actual |≤ΔN f ; In terms of discharge control, the minimum particle size of the final crystallizer product is D f-min , the maximum particle size is D f-max , the crystal size is monitored in real time by the particle size sensor. f-actual ≥D f-min And D f-actual ≤D f-max When D f-actual <D f-min and D f-actual >D f-max When the material returns to the intermediate crystallizer, the material return device is started to return the unqualified crystals to the intermediate crystallizer for continued growth.

8. An automatic control system for ammonium chloride crystal particles according to claim 1, characterized in that: The controller unit responds to the data collected by the sensor and generates precise control instructions according to the control algorithm, specifically including: Primary crystallization stage: The controller controls the temperature and additive concentration in the primary crystallizer by adjusting the coolant flow regulating valve and the additive adding pump according to the primary crystallization temperature and concentration. At the same time, the agitator speed regulating device is started to promote rapid mixing of materials to form uniform crystal nuclei. The temperature, liquid level and particle size changes in the primary crystallizer are continuously monitored. According to the data of the liquid level sensor, the material delivery pump is started to deliver the primary crystal product to the intermediate crystallizer. Intermediate crystallization stage: The controller adjusts the coolant flow rate and additive addition amount according to the target temperature and concentration of the intermediate crystallizer, and reduces the agitator speed at the same time. Based on the feedback from the particle size sensor, the material circulation pump returns the crystals that have not yet reached the standard to the intermediate crystallizer for continued growth, so that the crystal size distribution is uniform; Final crystallization stage: control the temperature in the final crystallizer, adjust the coolant flow and additive addition, further reduce the agitator speed, use the particle size screening device in the final crystallizer to monitor the discharge particle size in real time, and return particles that do not meet the size requirements to the intermediate crystallizer for continued growth.

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