Method and system for online monitoring crystallization metastable region of high-impurity-content and low-light-transmittance crystallization system by using image method to assist conductivity method

Abstract

The invention discloses a method and a system for online monitoring a crystallization metastable region of a high-impurity-content and low-light-transmittance crystallization system by an image method assisted conductivity method, and belongs to the field of industrial crystallization data testing. The system comprises a slurry pre-separating tank, a solution receiving tank, a crystal nucleus responder, a crystallization circulating water tank, a slurry conveying pump, a circulating water pump, a crystallization circulating water pump, a combined filter, a circulating water filter, a circulating water heater, first to thirteenth valves and vacuumizing equipment. According to the method, crystal nucleus formation can be quickly responded, the reliability and repeatability of crystallization metastable zone data determination are improved, AMASOX, GE, NKK and other ammonia process desulfurization by-product ammonium sulfate are guided to be properly nucleated in a crystallization metastable zone, crystals with large particle sizes are generated, and separation of ammonium sulfate crystals by a centrifugal machine is facilitated. According to the method, the ammonia desulfurization efficiency is improved, SO2 in the sulfur-containing flue gas is recycled to generate high-quality ammonium sulfate, and the method has certain economic benefits and environmental protection benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial crystallization data testing, and specifically relates to a method and system for online monitoring of a crystallization metastable zone of a high-impurity and low-transmittance crystal system by using an image method assisted by an electrical conductivity method. Background Art

[0002] Ammonium sulfate is a fast-acting fertilizer and biological fertilizer. It is also a way for the steel and coal-fired power industries to utilize SO2 through ammonia desulfurization processes. Currently, the AMASOX ammonia process, GE ammonia process and NKK ammonia process are mainly used. However, in actual operation, there are problems such as small (NH4)2SO4 crystals and centrifuge blockage that cannot be separated. In the industrial crystallization process, controlling the ammonium sulfate solution system in the metastable zone between the supersolution curve and the dissolution curve can avoid explosive nucleation and allow crystal growth. In addition, this type of process introduces various impurities due to flue gas, raw ammonia water and equipment corrosion, including organic impurities such as oils and phenols, fly ash, Al 3 + , Fe 3+ , Cl - This makes the composition of ammonium sulfate mother liquor complex and its transparency low, which increases the difficulty of determining the metastable zone of ammonium sulfate solution crystallization.

[0003] At present, the methods for determining the metastable zone of crystals mainly include visual inspection, Coulter counting method and laser method. The visual inspection method is affected by human factors and the measurement accuracy and repeatability are unstable. The Coulter counting method and laser method are not accurate in determining the solution with low light transmittance, and the crystal nucleus generation cannot respond. Chinese patent CN102680511A discloses a method for online monitoring of solubility, metastable zone and solution concentration in the crystallization process of an organic salt system. The method can determine the dissolution temperature of the system according to the mutation point in the conductivity-temperature relationship curve during the heating process, thereby determining the solubility curve of the solute in the solvent; according to the mutation point in the conductivity-temperature relationship curve during the cooling process, the crystallization temperature of the system can be determined, thereby obtaining the metastable zone of the solution system under the cooling rate. For the recorded conductivity and temperature, the coefficient in the formula is calculated by the least squares method according to the relationship between conductivity and solution saturation temperature, and the relationship between conductivity and solution concentration is obtained, and then the supersaturation of the solution to be tested is calculated. This method is not suitable for inorganic salt systems, which also limits the scope of application of this method. Chinese patent CN110243825A discloses a method for measuring solubility, super solubility and solution concentration in a crystallization process based on an online image method, wherein the method obtains the solubility of the solution according to the initial solid-liquid mass ratio and the crystal mass concentration difference determined by the online image; the crystallization temperature of the system is determined according to the mutation point of the number of crystal particles in the solution system during the cooling process, thereby obtaining the super solubility curve and metastable zone of the system. Chinese patent CN112162003A discloses a device and method for measuring the width of the crystallization metastable zone of a microscale flow system, wherein a solution to be tested having a temperature of an initial test temperature and reaching a saturated state at the initial test temperature is injected into a microchannel at a constant flow rate by an injection pump, and the magnification effect of a microscope on the microchannel is combined, and a camera is used to take real-time photos of the liquid to be tested in the microchannel, so as to capture the crystallization state of the fluid, obtain the crystallization point temperature, and calculate the difference between the initial test temperature and the crystallization point temperature, which is the crystallization metastable zone width of the microscale flow system of the solution to be tested. Chinese patent CN101788464A discloses an online detection method and a special device for solution concentration during dissolution crystallization. After the sample is filtered through a sampling tube equipped with a microfilter at the front end to remove crystal particles in the solution, it is continuously extracted from the crystallization kettle by a sampling pump and sent to the detection pool; an ultraviolet fiber optic spectrometer is used to continuously record the ultraviolet absorption spectrum of the solution in the detection pool and transmit it to a computer for real-time recording, and the measured solution flows back to the crystallization kettle; the computer uses the orthogonal signal correction OSC method to correct the continuously recorded ultraviolet detection spectrum, and then takes the absorbance value at any wavelength within the ultraviolet region of 200-400nm, and uses the least squares method to obtain the calculation coefficient in the Lambert-beer law calculation formula, and then calculates the solute concentration of the solution to be tested at a certain time. The above three methods all have the problem of low accuracy when measuring solutions with low light transmittance.Chinese patent CN104502222A discloses a method for determining the metastable zone of a high-concentration, low-transmittance solution system in response to a microporous membrane. The solution to be tested is added to a crystallization kettle, and the solution to be tested is circulated to keep the temperature, stirring and circulation pump flow rate in the crystallization kettle stable; the steam permeating the membrane returns to the solvent storage tank with the cooling circulating solvent, and the solvent permeating the membrane is weighed and converted into a distillation rate; the concentration of the solution to be tested at each moment is obtained by the total mass of the solvent distilled at each moment; the inflection point moment when the distillation rate decreases is the nucleation moment of the crystal, and the concentration of the solution to be tested at this time is the spontaneous nucleation concentration under this operating condition, and the difference between the spontaneous nucleation concentration and the saturated concentration of the solution to be tested is the metastable zone width of the solution to be tested under this operating condition. This method has the following problems: when many impurities in the ammonium sulfate solution block the microporous membrane material, the evaporation rate also decreases, resulting in the illusion of the formation of tiny crystal nuclei, resulting in a narrowing of the measured metastable zone width.

[0004] It can be seen that for crystal systems with low transmittance and high impurities, the existing measurement methods generally have the problem of low measurement accuracy. Therefore, it is necessary to develop a measurement method with a wide range of adaptability and high accuracy, especially a method suitable for the determination of the crystal metastable zone of industrial crystal systems with high impurities and low transmittance. Summary of the invention

[0005] In order to solve the problems of low measurement accuracy, unsuitability for inorganic salt systems and narrow application range in the existing methods for measuring the crystallization metastable zone of a crystallization system, the present invention provides a method and system for online monitoring of the crystallization metastable zone of a high-impurity and low-transmittance crystallization system using an image method assisted by a conductivity method.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] The present invention provides an image-assisted conductivity method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system, comprising a slurry pre-dividing tank, a solution receiving tank, a crystal nucleus responder, a crystallization circulating water tank, a slurry delivery pump, a circulating water pump, a crystallization circulating water pump, a combined filter, a circulating water filter, a circulating water heater, a first valve to a thirteenth valve, and a vacuum pump;

[0008] The circulating water heater is connected to the circulating water filter; the circulating water filter is connected to the circulating water pump; the circulating water pump is connected to the slurry pre-dividing tank jacket through the second valve, and the circulating water pump is connected to the crystal nucleus responder jacket through the first valve; the slurry pre-dividing tank is connected to the combined filter; the combined filter is connected to the slurry delivery pump; the slurry delivery pump is connected to the solution receiving tank through the third valve; the slurry pre-dividing tank is connected to the solution receiving tank jacket through the eighth valve, the solution receiving tank is connected to the vacuum pumping device through the fourth valve, the solution receiving tank is connected to the crystal nucleus responder through the fifth valve, and the solution receiving tank jacket is connected to the circulating water heater through the sixth valve; the crystal nucleus responder is connected to the vacuum pumping device through the twelfth valve, the crystal nucleus responder jacket is connected to the circulating water heater through the thirteenth valve, and the crystal nucleus responder jacket is connected to the crystallization circulating water tank; the crystallization circulating water tank is connected to the circulating water heater through the eleventh valve, the ninth valve, the seventh valve and the sixth valve; the crystallization circulating water tank is connected to the crystallization circulating water pump; the crystallization circulating water pump is connected to the circulating water heater through the ninth valve and the seventh valve;

[0009] A first agitator is installed in the slurry pre-separation tank, and a first infrared optical fiber monitoring probe and a first infrared temperature monitoring probe are placed on the upper end of the first agitator;

[0010] A second agitator is installed in the solution receiving tank, and a second infrared optical fiber monitoring probe and a second infrared temperature monitoring probe are placed on the upper end of the second agitator.

[0011] The upper part of the crystal core responder is provided with two layers of staggered distribution of thermal sensitive trays, namely the first layer tray and the second layer tray, a third infrared optical fiber monitoring probe and a third infrared temperature monitoring probe are placed on the first layer tray, and a fourth infrared optical fiber monitoring probe and a fourth infrared temperature monitoring probe are placed on the second layer tray;

[0012] The central part of the crystal core responder is provided with three groups of vertical hydrophobic thin tubes, and a first online extended objective lens high-definition optical microscope intelligent comparison system is placed on the three groups of vertical hydrophobic thin tubes;

[0013] The lower part of the crystal core responder is provided with a Y-shaped crystal core main response area, and a second online extended objective lens high-definition optical microscope intelligent comparison system and a fifth infrared optical fiber monitoring probe are placed in the Y-shaped crystal core main response area;

[0014] The bottom of the crystal core responder is also provided with a tenth valve and a liquid discharge port;

[0015] A sixth infrared temperature monitoring probe is placed in the crystallization circulating water tank;

[0016] A fifth infrared temperature monitoring probe is placed in the circulating water heater.

[0017] Furthermore, the present invention also includes an intelligent temperature control system, which is respectively connected to the first infrared temperature monitoring probe, the second infrared temperature monitoring probe, the third infrared temperature monitoring probe, the fourth infrared temperature monitoring probe, the fifth infrared temperature monitoring probe and the sixth infrared temperature monitoring probe; the intelligent temperature control system is used to accurately record the operating temperature of each module according to industrial crystallization conditions using an integrated display control method, and quickly respond to crystal nucleus formation.

[0018] The present invention provides a method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystallization system by an image method assisted by a conductivity method, which is implemented by using the system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystallization system by an image method assisted by a conductivity method, and the method comprises the following steps:

[0019] (1) System temperature rise;

[0020] Turn on the circulating water heater and set the heating temperature, turn on the circulating water filter, circulating water pump, the first valve, the second valve, the sixth valve, the eighth valve and the thirteenth valve, the heated circulating water passes through the circulating water filter, the circulating water pump, the second valve in turn into the slurry pre-separation tank jacket, then from the slurry pre-separation tank jacket through the eighth valve into the solution receiving tank jacket, and from the solution receiving tank jacket through the sixth valve back to the circulating water heater; the circulating water passes through the circulating water filter, the circulating water pump, the first valve in turn into the crystal nucleus responder jacket, and then from the crystal nucleus responder jacket through the thirteenth valve back to the circulating water heater, so that the slurry pre-separation tank, the solution receiving tank, and the crystal nucleus responder are preheated to 35-95°C;

[0021] (2) Nucleus responder lead;

[0022] Open the combined filter, the slurry delivery pump and the third valve, introduce the industrial ammonium sulfate slurry into the slurry pre-separation tank, stir the industrial ammonium sulfate slurry in the slurry pre-separation tank with the first agitator, and when the temperature stabilizes to 35-95°C, stop stirring and let it stand for 5-10 minutes to pre-precipitate ammonium sulfate solid. The industrial ammonium sulfate slurry with low solid content in the upper part is filtered through the combined filter to remove impurities and ammonium sulfate crystals, and then the ammonium sulfate solid and particulate impurities are separated to obtain a saturated ammonium sulfate solution with low impurity content and high transparency. The saturated ammonium sulfate solution is pumped to a solution receiving tank with a temperature of 35-95°C by a slurry delivery pump and is heated to 35-95°C. Use the second stirrer to stir under the constant temperature condition, and convert the solution conductivity in the solution receiving tank into solution concentration, recorded as c0, and record the temperature T0 at this time; open the fourth valve, the fifth valve, the twelfth valve and the vacuum equipment, and slowly introduce the saturated ammonium sulfate solution in the solution receiving tank into the two layers of staggered thermal-sensitive tower plates on the upper part of the crystal core responder under the negative pressure of the system, until the solution fills the three groups of vertical hydrophobic thin tubes in the middle of the crystal core responder and reaches the Y-shaped crystal core main response area at the lower part of the crystal core responder, stop the crystal core responder from feeding, maintain a constant temperature of 35-95°C, and after the test, open the tenth valve of the crystal core responder to discharge the liquid through the liquid discharge port;

[0023] (3) Monitoring of crystal nucleation response;

[0024] Close the first valve, the eleventh valve and the thirteenth valve, start the crystallization circulation water pump, open the natural cooling circulation process of the circulating water between the crystallization circulation water tank and the crystal nucleus responder jacket, and realize the slow natural cooling of the ambient temperature; the conductivity change inflection point of the first layer of tower plate on the upper part of the crystal nucleus responder and the Y-shaped crystal nucleus main response area at the lower part of the crystal nucleus responder responds to the crystal nucleus formation, and the first online extended objective lens high-definition optical microscope intelligent comparison system of the three groups of vertical hydrophobic thin tubes in the middle of the crystal nucleus responder and the second online extended objective lens high-definition optical microscope intelligent comparison system of the Y-shaped crystal nucleus main response area assist in capturing the crystal nucleus formation transient, assist in responding to the conductivity change inflection point of the crystal nucleus formation, and record the temperature value T1 of the crystal nucleus formation at the same time, and the computer collects real-time data and automatically forms a crystal nucleus response transient diagram;

[0025] (4) Mapping of the crystallization metastable zone;

[0026] The above steps are repeated multiple times at 35-95°C and the obtained parameters are recorded. A solubility curve is drawn according to the temperature of the saturated ammonium sulfate solution in the solution receiving tank and the concentration converted from the conductivity. A super solubility curve is drawn according to the conductivity change inflection point of the first layer of tower plate on the upper part of the crystal nucleus responder and the Y-type crystal nucleus main response area at the lower part of the crystal nucleus responder, the corresponding temperature T1 and the crystal nucleus response transient diagram. The curve between the solubility curve and the super solubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

[0027] Furthermore, in step (1), the circulating water heater is turned on and the heating temperature is set to 30-100°C.

[0028] Furthermore, in step (1), deionized water is used as a standard solution to calibrate the conductivity measurement points of the circulating water in the slurry pre-separation tank, the solution receiving tank and the second layer of the tower plate on the upper part of the crystal core responder.

[0029] Furthermore, in step (1), circulating water from a circulating water heater is circulated between the slurry pre-separation tank, the solution receiving tank, the crystal nucleus responder, the crystallization circulating water tank and the circulating water heater to simulate the temperature of the ammonium sulfate slurry / solution under industrial crystallization conditions.

[0030] Furthermore, in step (2), the industrial ammonium sulfate slurry is stirred in the slurry pre-separation tank using a first agitator, and the stirring rate ranges from 40 to 400 r / min.

[0031] Furthermore, in step (2), a second stirrer is used for stirring at a constant temperature of 35 to 95° C., and a stirring rate ranges from 40 to 300 r / min.

[0032] Furthermore, in step (2), saturated ammonium sulfate solution is used as a standard solution to calibrate the conductivity measurement points of the solution in the first layer of the upper tray and the lower Y-shaped crystal core main response area of ​​the crystal core responder.

[0033] Furthermore, the temperature of the circulating water in the circulating water heater is detected by the fifth infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the industrial ammonium sulfate slurry in the slurry pre-separation tank are detected by the first infrared optical fiber monitoring probe and the first infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the solution receiving tank are detected by the second infrared optical fiber monitoring probe and the second infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the first layer of tower plate on the upper part of the crystal nucleus responder are detected by the third infrared optical fiber monitoring probe and the third infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the second layer of tower plate on the upper part of the crystal nucleus responder are detected by the fourth infrared optical fiber monitoring probe and the fourth infrared temperature monitoring probe; the conductivity of the circulating water and the solution in the Y-shaped crystal nucleus main response area at the lower part of the crystal nucleus responder is detected by the fifth infrared optical fiber monitoring probe; and the temperature of the circulating water in the crystallization circulating water tank is detected by the sixth infrared temperature monitoring probe.

[0034] The beneficial effects of the present invention are:

[0035] The present invention combines the wet desulfurization process and the crystallization metastable zone determination technology to creatively develop a determination method suitable for online monitoring of the crystallization metastable zone of the ammonium sulfate slurry crystallization system, and proposes a method and system for online monitoring of the crystallization metastable zone of the high-impurity, low-transmittance crystallization system using an image method assisted by an electrical conductivity method, the purpose of which is to quickly respond to the formation of crystal nuclei, improve the reliability and repeatability of the crystallization metastable zone data determination, and guide the ammonium sulfate byproduct of ammonia desulfurization such as AMASOX, GE and NKK to nucleate appropriately in the crystallization metastable zone, produce crystals with larger particle sizes, and facilitate the separation of ammonium sulfate crystals by a centrifuge. The present invention not only improves the efficiency of ammonia desulfurization, but also recycles SO2 in sulfur-containing flue gas to produce high-quality ammonium sulfate, which has certain economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a simplified flow chart of a method for online monitoring of the crystallization metastable zone (CGMZ) of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method.

[0037] Figure 2 The intelligent contrast system of the online extended objective high-definition optical microscope assists in capturing the instantaneous image of crystal nucleus formation.

[0038] Figure 3 Schematic diagram of the crystallization metastable zone of industrial ammonium sulfate slurry crystallization system. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0040] In a first aspect, the present invention provides a method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method.

[0041] The invention discloses an image-assisted conductivity method for online monitoring of the crystal metastable zone (CGMZ) of a high-impurity, low-transmittance crystal system, which is particularly suitable for the determination of the crystal nucleation response and metastable zone of an industrial ammonium sulfate slurry crystal system with high impurities and low transmittance. The specific implementation process is as follows:

[0042] (1) System construction;

[0043] according to Figure 1The test system is built by connection method. The system mainly includes: slurry pre-dividing tank V-1, solution receiving tank V-2, crystal nucleus responder V-3, crystallization circulating water tank V-4, slurry delivery pump PU-1, circulating water pump PU-2, crystallization circulating water pump PU-3, combined filter STN-1, circulating water filter STN-2, circulating water heater HEAT-1, first infrared fiber optic monitoring probe CIR01, second infrared fiber optic monitoring probe CIR02, third infrared fiber optic monitoring probe CIR03, fourth infrared fiber optic monitoring probe CIR04, fifth Infrared fiber optic monitoring probe CIR05, first infrared temperature monitoring probe TIR01, second infrared temperature monitoring probe TIR02, third infrared temperature monitoring probe TIR03, fourth infrared temperature monitoring probe TIR04, fifth infrared temperature monitoring probe TIR05, sixth infrared temperature monitoring probe TIR06, first online extended objective lens high-definition optical microscope intelligent comparison system YGR01, second online extended objective lens high-definition optical microscope intelligent comparison system YGR02, first valve 1 to thirteenth valve 13, vacuum equipment and intelligent temperature control system.

[0044] Among them, a first agitator V-11 is installed in the slurry pre-dividing tank V-1, and a first infrared optical fiber monitoring probe CIR01 and a first infrared temperature monitoring probe TIR01 are placed on the upper end of the first agitator V-11.

[0045] Among them, a second agitator V-21 is installed in the solution receiving tank V-2, and a second infrared fiber optic monitoring probe CIR02 and a second infrared temperature monitoring probe TIR02 are placed on the upper end of the second agitator V-21.

[0046] Among them, two layers of staggered distribution of thermal sensitive tower plates (first tower plate V-31 and second tower plate V-32) are arranged inside the upper part of the crystal core responder V-3. At the same time, the third infrared optical fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03 are placed on the first tower plate V-31, and the fourth infrared optical fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04 are placed on the second tower plate V-32; three sets of vertical hydrophobic Thin tube array V-33, and the first online extended objective lens high-definition optical microscope intelligent comparison system YGR01 is placed on the three groups of vertical hydrophobic thin tube arrays V-33; a Y-type crystal nucleus main response area V-34 is arranged at the lower part of the crystal nucleus responder V-3, and the second online extended objective lens high-definition optical microscope intelligent comparison system YGR02 and the fifth infrared optical fiber monitoring probe CIR05 are placed in the Y-type crystal nucleus main response area V-34; the bottom of the crystal nucleus responder V-3 is also provided with a tenth valve 10 and a liquid discharge port.

[0047] Among them, the sixth infrared temperature monitoring probe TIR06 is placed in the crystallization circulation water tank V-4.

[0048] Among them, the fifth infrared temperature monitoring probe TIR05 is placed in the circulating water heater HEAT-1.

[0049] The connection relationship between the above components is:

[0050] The circulating water heater HEAT-1 is connected to the circulating water filter STN-2 through a pipeline; the circulating water filter STN-2 is connected to the circulating water pump PU-2 through a pipeline; the circulating water pump PU-2 is connected to the jacket of the slurry pre-division tank V-1 through a pipeline and the second valve 2, and the circulating water pump PU-2 is connected to the jacket of the crystal nucleus responder V-3 through a pipeline and the first valve 1; the slurry pre-division tank V-1 is connected to the combined filter STN-1 through a pipeline; the combined filter STN-1 is connected to the slurry delivery pump PU-1 through a pipeline; the slurry delivery pump PU-1 is connected to the solution receiving tank V-2 through a pipeline and the third valve 3; the slurry pre-division tank V-1 is connected to the jacket of the solution receiving tank V-2 through a pipeline and the eighth valve 8, the solution receiving tank V-2 is connected to the vacuum pumping equipment through a pipeline and the fourth valve 4, and the solution receiving tank V-2 is connected to the vacuum pumping equipment through a pipeline and the fourth valve 4. The crystal nucleus responder V-3 is connected to the crystal nucleus responder V-3 through the pipeline and the fifth valve 5, and the solution receiving tank V-2 jacket is connected to the circulating water heater HEAT-1 through the pipeline and the sixth valve 6; the crystal nucleus responder V-3 is connected to the vacuum equipment through the pipeline and the twelfth valve 12, the crystal nucleus responder V-3 jacket is connected to the circulating water heater HEAT-1 through the pipeline and the thirteenth valve 13, the crystal nucleus responder V-3 jacket is connected to the crystallization circulating water tank V-4 through the pipeline, the crystallization circulating water tank V-4 is connected to the circulating water heater HEAT-1 through the pipeline, the eleventh valve 11, the ninth valve 9, the seventh valve 7 and the sixth valve 6; the crystallization circulating water tank V-4 is connected to the crystallization circulating water pump PU-3 through the pipeline; the crystallization circulating water pump PU-3 is connected to the circulating water heater HEAT-1 through the pipeline, the ninth valve 9 and the seventh valve 7.

[0051] In the present invention, the intelligent temperature control system is respectively connected to the first infrared temperature monitoring probe TIR01, the second infrared temperature monitoring probe TIR02, the third infrared temperature monitoring probe TIR03, the fourth infrared temperature monitoring probe TIR04, the fifth infrared temperature monitoring probe TIR05, and the sixth infrared temperature monitoring probe TIR06. The intelligent temperature control system is mainly used to accurately record the operating temperature of each module in an integrated display control mode according to industrial crystallization conditions, quickly respond to crystal nucleus formation, and improve the reliability and repeatability of crystallization metastable zone data determination.

[0052] (2) System temperature rise;

[0053] Before the system is put into operation, it should be ensured that there are no leaks in the pipeline, the sealing is good, the instruments are in good condition, the power supply to the energized equipment is completed, and the conductivity measuring points are calibrated and ready for use.

[0054] Turn on the circulating water heater HEAT-1 and set the heating temperature to 30-100°C. During the heating process, the temperature of the circulating water is detected by the fifth infrared temperature monitoring probe TIR05; turn on the circulating water filter STN-2, the circulating water pump PU-2, the first valve 1, the second valve 2, the sixth valve 6, the eighth valve 8 and the thirteenth valve 13, so that the heated circulating water enters the slurry pre-separation tank V-1 jacket, the solution receiving tank V-2 jacket and the crystal nucleus responder V-3 jacket respectively. Specifically, the circulating water passes through the circulating water filter STN-2, the circulating water pump PU-2, the first valve 1, the second valve 2, the sixth valve 6, the eighth valve 8 and the thirteenth valve 13 in sequence. -2, the second valve 2 enters the slurry pre-separation tank V-1 jacket, and then from the slurry pre-separation tank V-1 jacket through the eighth valve 8 into the solution receiving tank V-2 jacket, from the solution receiving tank V-2 jacket through the sixth valve 6 back to the circulating water heater HEAT-1; the circulating water passes through the circulating water filter STN-2, the circulating water pump PU-2, the first valve 1 into the crystal nucleus responder V-3 jacket, and then from the crystal nucleus responder V-3 jacket through the thirteenth valve 13 back to the circulating water heater HEAT-1, so that the slurry pre-separation tank V-1, the solution receiving tank V-2, the crystal nucleus responder V-3 jacket The responder V-3 is preheated to 35-95°C. During the heating process, the conductivity and temperature of the circulating water in the slurry pre-separation tank V-1 are detected by the first infrared optical fiber monitoring probe CIR01 and the first infrared temperature monitoring probe TIR01. The conductivity and temperature of the circulating water in the solution receiving tank V-2 are detected by the second infrared optical fiber monitoring probe CIR02 and the second infrared temperature monitoring probe TIR02. The conductivity and temperature of the circulating water in the first layer of the tower plate V-31 on the upper part of the crystal nucleus responder V-3 are detected by the third infrared optical fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03. The conductivity and temperature of water are detected by the fourth infrared fiber optic monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04, and the conductivity and temperature of circulating water in the second layer tower plate V-32 on the upper part of the crystal nucleus responder V-3 are detected by the fifth infrared fiber optic monitoring probe CIR05. At the same time, the conductivity of circulating water in the Y-shaped crystal nucleus main response area V-34 at the lower part of the crystal nucleus responder V-3 is detected. At the same time, deionized water is used as the standard solution to calibrate the conductivity measuring points of circulating water in the slurry pre-separation tank V-1, the solution receiving tank V-2 and the second layer tower plate V-32 on the upper part of the crystal nucleus responder V-3.

[0055] At this point, the circulating water from the circulating water heater HEAT-1 can be circulated between the slurry pre-separation tank V-1, the solution receiving tank V-2, the crystal nucleus responder V-3, the crystallization circulating water tank V-4 and the circulating water heater HEAT-1 to simulate the temperature of the ammonium sulfate slurry / solution under industrial crystallization conditions.

[0056] (3) Nucleus responder lead-in;

[0057] Open the combined filter STN-1, the slurry delivery pump PU-1 and the third valve 3, introduce the industrial ammonium sulfate slurry into the slurry pre-separation tank V-1, and obtain a saturated ammonium sulfate slurry with a low solid content after stirring, heat preservation and pre-precipitation in the slurry pre-separation tank V-1. Specifically, the industrial ammonium sulfate slurry is stirred by the first agitator V-11 in the slurry pre-separation tank V-1 to stabilize the temperature. The stirring rate range is 40 to 400 r / min. At the same time, the conductivity and temperature of the industrial ammonium sulfate slurry in the slurry pre-separation tank V-1 are detected by the first infrared optical fiber monitoring probe CIR01 and the first infrared temperature monitoring probe TIR01. When the temperature is stable When the temperature reaches 35-95°C, stop stirring and let stand for 5-10 minutes to pre-precipitate ammonium sulfate solid. The industrial ammonium sulfate slurry with low solid content in the upper part is filtered through the combined filter STN-1 to remove impurities and ammonium sulfate crystals, and then the ammonium sulfate solid and particulate impurities are separated to obtain a saturated ammonium sulfate solution with low impurity content and high transparency. The saturated ammonium sulfate solution is pumped to the solution receiving tank V-2 with a temperature of 35-95°C through the slurry delivery pump PU-1, and stirred by the second stirrer V-21 under the constant temperature condition of 35-95°C, and the stirring rate ranges from 40 to 300 r / min. At the same time, the second infrared optical fiber monitoring probe CI R02 and the second infrared temperature monitoring probe TIR02 detect the conductivity and temperature of the solution in the solution receiving tank V-2, and convert the conductivity into solution concentration, recorded as c0, and record the temperature T0 at this time; open the fourth valve 4, the fifth valve 5, the twelfth valve 12 and the vacuum equipment, and slowly introduce the saturated ammonium sulfate solution in the solution receiving tank V-2 into the two layers of staggered thermal sensitive trays (the first layer tray V-31 and the second layer tray V-32) on the upper part of the crystal nucleus responder V-3 under the negative pressure of the system to buffer the solution delivery pressure and avoid errors caused by splashing and hanging on the wall. At the same time, the third infrared fiber optic monitoring probe CIR03 and The third infrared temperature monitoring probe TIR03 detects the conductivity and temperature of the solution in the first layer of the tower plate V-31, and the fourth infrared optical fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04 detect the conductivity and temperature of the solution in the second layer of the tower plate V-32, until the solution fills the three groups of vertical hydrophobic thin tubes V-33 in the middle of the crystal core responder V-3 and reaches the Y-type crystal core main response area V-34 at the bottom of the crystal core responder V-3. At the same time, the fifth infrared optical fiber monitoring probe CIR05 detects the conductivity of the solution in the Y-type crystal core main response area V-34, stops the crystal core responder V-3 from feeding, and maintains a constant temperature of 35 to 95°C. After the test is completed, open the tenth valve 10 of the crystal core responder V-3 to drain the liquid through the liquid discharge port. All signals of temperature, conductivity and pump flow are centrally controlled and displayed, and the conductivity of the saturated ammonium sulfate solution in the solution receiving tank V-2 is converted into concentration in real time, and the conductivity is displayed in real time.

[0058] (4) Monitoring of crystal nucleation response;

[0059] Close the first valve 1, the eleventh valve 11 and the thirteenth valve 13, open the crystallization circulating water pump PU-3, open the natural cooling circulation process of the circulating water between the crystallization circulating water tank V-4 and the crystal nucleus responder V-3 jacket, realize the slow natural cooling of the ambient temperature, and at the same time detect the temperature of the circulating water in the crystallization circulating water tank V-4 through the sixth infrared temperature monitoring probe TIR06. Specifically, the circulating water between the jacket of the crystal nucleus responder V-3 flows back to the circulating water heater HEAT-1 through the crystallization circulating water tank V-4, the crystallization circulating water pump PU-3, the ninth valve 9, the seventh valve 7, and the sixth valve 6 in turn. Then the circulating water passes through the circulating water heater HEAT-1, the circulating water filter STN-2, the circulating water pump PU-2, and the second valve 2 in turn to enter the slurry pre-separation tank V-1 jacket, and then enters the solution receiving tank V-2 jacket from the slurry pre-separation tank V-1 jacket through the eighth valve 8, and flows back to the circulating water heater HEAT-1 from the solution receiving tank V-2 jacket through the sixth valve 6. The conductivity change inflection point of the first layer tower plate V-31 on the upper part of the crystal nucleus responder V-3 and the Y-shaped crystal nucleus main response area V-34 at the lower part of the crystal nucleus responder V-3 responds to the crystal nucleus formation. The first online extended objective lens high-definition optical microscope intelligent comparison system YGR01 of the three groups of vertical hydrophobic fine tubes V-33 in the middle part of the crystal nucleus responder V-3 and the second online extended objective lens high-definition optical microscope intelligent comparison system YGR02 of the Y-shaped crystal nucleus main response area V-34 assist in capturing the crystal nucleus formation transient and assist in responding to the conductivity change inflection point of the crystal nucleus formation. At the same time, the temperature value T1 of the crystal nucleus formation is recorded. The above parameters are displayed locally and centrally. The computer collects real-time data and automatically forms a crystal nucleus response transient diagram.

[0060] (5) Mapping of the crystallization metastable zone;

[0061] Repeat the above steps (1) to (4) multiple times at a temperature of 35 to 95°C and record the obtained parameters. Draw a solubility curve based on the temperature and conductivity-converted concentration of the saturated ammonium sulfate solution in the solution receiving tank V-2. Draw a super solubility curve based on the conductivity change inflection point of the first layer tower plate V-31 on the upper part of the crystal nucleus responder V-3, the Y-type crystal nucleus main response area V-34 at the lower part of the crystal nucleus responder V-3, the corresponding temperature T1 and the crystal nucleus response transient diagram. The curve between the solubility curve and the super solubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

[0062] In the present invention, the conductivity measurement points of the slurry pre-dividing tank V-1, the solution receiving tank V-2, and the second layer tower plate V-32 on the upper part of the crystal nucleus responder V-3 use deionized water as the standard solution, and the conductivity measurement points of the solution in the first layer tower plate V-31 on the upper part of the crystal nucleus responder V-3 and the lower Y-shaped crystal nucleus main response area V-34 use saturated ammonium sulfate solution as the standard solution. The present invention not only realizes the detection of the conductivity of the saturated ammonium sulfate solution and the calculation of the solubility, but also realizes the multi-point measurement of the conductivity inside the crystal nucleus responder V-3, and quickly responds to the formation of crystal nuclei.

[0063] In the second aspect, the present invention provides a system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystallization system by using an image-assisted conductivity method, which is used to implement the method provided in the first aspect of the present invention for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystallization system by using an image-assisted conductivity method.

[0064] The invention discloses an image-assisted conductivity method for online monitoring of the crystal metastable zone of a high-impurity, low-transmittance crystal system, which mainly comprises: a combined filtering system, a crystal nucleus response detection system and an intelligent temperature control system.

[0065] In the present invention, the combined filtration system comprises graded filter cloth and microporous membrane, which realizes the filtration of impurities of different particle sizes and improves the transparency of industrial ammonium sulfate slurry. The combined filtration system mainly comprises: a combined filter STN-1 and a circulating water filter STN-2.

[0066] In the present invention, the crystal nucleus response detection system mainly includes a negative pressure feeding system, a crystal nucleus response monitoring system and an online extended objective lens high-definition optical microscope intelligent comparison system. The negative pressure feeding system is used to simulate the vacuum degree of the system crystallization process, the crystal nucleus response monitoring system is used to monitor the inflection point of the conductivity change before and after the crystal nucleus response and its corresponding temperature, and the online extended objective lens high-definition optical microscope intelligent comparison system is used to assist in responding to the transient state of crystal nucleus formation.

[0067] In the present invention, the negative pressure feeding system mainly includes: a vacuum pumping device, a first valve 4 and a twelfth valve 12.

[0068] In the present invention, the crystal nucleus response monitoring system mainly includes: a slurry pre-division tank V-1, a solution receiving tank V-2, a crystal nucleus responder V-3, a crystallization circulating water tank V-4, a slurry delivery pump PU-1, a circulating water pump PU-2, a crystallization circulating water pump PU-3, a circulating water heater HEAT-1, a first infrared fiber optic monitoring probe CIR01, a second infrared fiber optic monitoring probe CIR02, a third infrared fiber optic monitoring probe CIR03, a fourth infrared fiber optic monitoring probe CIR04, a fifth infrared fiber optic monitoring probe CIR05, a first infrared temperature monitoring probe TIR01, a second infrared temperature monitoring probe TIR02, a third infrared temperature monitoring probe TIR03, a fourth infrared temperature monitoring probe TIR04, a fifth infrared temperature monitoring probe TIR05, a sixth infrared temperature monitoring probe TIR06, a first valve 1 to a third valve 3, a fifth valve 5 to an eleventh valve 11, and a thirteenth valve 13.

[0069] Among them, a first agitator V-11 is installed in the slurry pre-dividing tank V-1, and a first infrared optical fiber monitoring probe CIR01 and a first infrared temperature monitoring probe TIR01 are placed on the upper end of the first agitator V-11.

[0070] Among them, a second agitator V-21 is installed in the solution receiving tank V-2, and a second infrared fiber optic monitoring probe CIR02 and a second infrared temperature monitoring probe TIR02 are placed on the upper end of the second agitator V-21.

[0071] Among them, two layers of staggered distribution of thermal sensitive tower plates (first tower plate V-31 and second tower plate V-32) are arranged inside the upper part of the crystal core responder V-3. At the same time, the third infrared optical fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03 are placed on the first tower plate V-31, and the fourth infrared optical fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04 are placed on the second tower plate V-32; three sets of vertical hydrophobic Thin tube array V-33, and the first online extended objective lens high-definition optical microscope intelligent comparison system YGR01 is placed on the three groups of vertical hydrophobic thin tube arrays V-33; a Y-type crystal nucleus main response area V-34 is arranged at the lower part of the crystal nucleus responder V-3, and the second online extended objective lens high-definition optical microscope intelligent comparison system YGR02 and the fifth infrared optical fiber monitoring probe CIR05 are placed in the Y-type crystal nucleus main response area V-34; the bottom of the crystal nucleus responder V-3 is also provided with a tenth valve 10 and a liquid discharge port.

[0072] Among them, the sixth infrared temperature monitoring probe TIR06 is placed in the crystallization circulation water tank V-4.

[0073] Among them, the fifth infrared temperature monitoring probe TIR05 is placed in the circulating water heater HEAT-1.

[0074] In the present invention, the online extended objective lens high-definition optical microscope intelligent comparison system mainly includes: a first online extended objective lens high-definition optical microscope intelligent comparison system YGR01 and a second online extended objective lens high-definition optical microscope intelligent comparison system YGR02.

[0075] In the present invention, the intelligent temperature control system is mainly used to accurately record the operating temperature of each module by using an integrated display control method according to industrial crystallization conditions, quickly respond to crystal nucleus formation, and improve the reliability and repeatability of crystallization metastable zone data determination.

[0076] The connection relationship between the above components is:

[0077] The circulating water heater HEAT-1 is connected to the circulating water filter STN-2 through a pipeline; the circulating water filter STN-2 is connected to the circulating water pump PU-2 through a pipeline; the circulating water pump PU-2 is connected to the jacket of the slurry pre-division tank V-1 through a pipeline and the second valve 2, and the circulating water pump PU-2 is connected to the jacket of the crystal nucleus responder V-3 through a pipeline and the first valve 1; the slurry pre-division tank V-1 is connected to the combined filter STN-1 through a pipeline; the combined filter STN-1 is connected to the slurry delivery pump PU-1 through a pipeline; the slurry delivery pump PU-1 is connected to the solution receiving tank V-2 through a pipeline and the third valve 3; the slurry pre-division tank V-1 is connected to the jacket of the solution receiving tank V-2 through a pipeline and the eighth valve 8, the solution receiving tank V-2 is connected to the vacuum pumping equipment through a pipeline and the fourth valve 4, and the solution receiving tank V-2 is connected to the vacuum pumping equipment through a pipeline and the fourth valve 4. The crystal nucleus responder V-3 is connected to the crystal nucleus responder V-3 through the pipeline and the fifth valve 5, and the solution receiving tank V-2 jacket is connected to the circulating water heater HEAT-1 through the pipeline and the sixth valve 6; the crystal nucleus responder V-3 is connected to the vacuum equipment through the pipeline and the twelfth valve 12, the crystal nucleus responder V-3 jacket is connected to the circulating water heater HEAT-1 through the pipeline and the thirteenth valve 13, the crystal nucleus responder V-3 jacket is connected to the crystallization circulating water tank V-4 through the pipeline, the crystallization circulating water tank V-4 is connected to the circulating water heater HEAT-1 through the pipeline, the eleventh valve 11, the ninth valve 9, the seventh valve 7 and the sixth valve 6; the crystallization circulating water tank V-4 is connected to the crystallization circulating water pump PU-3 through the pipeline; the crystallization circulating water pump PU-3 is connected to the circulating water heater HEAT-1 through the pipeline, the ninth valve 9 and the seventh valve 7. The intelligent temperature control system is respectively connected to the first infrared temperature monitoring probe TIR01, the second infrared temperature monitoring probe TIR02, the third infrared temperature monitoring probe TIR03, the fourth infrared temperature monitoring probe TIR04, the fifth infrared temperature monitoring probe TIR05, and the sixth infrared temperature monitoring probe TIR06.

[0078] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0079] Example 1

[0080] The method of the present invention for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system by an image method-assisted conductivity method has the following specific implementation process:

[0081] (1) System construction;

[0082] according to Figure 1 The test system is built in the connection method, the system pipeline has no leaks, the sealing is good, the instruments are put into use in good condition, the power supply to the energized equipment is completed, and the conductivity measuring points are calibrated and ready for use.

[0083] (2) System temperature rise;

[0084] Turn on the circulating water heater HEAT-1 and set the heating temperature to 74°C. During the heating process, the temperature of the circulating water is detected by the fifth infrared temperature monitoring probe TIR05. Deionized water is used as the standard solution to calibrate the conductivity measuring points of the slurry pre-separation tank V-1, the solution receiving tank V-2, and the second layer of the tower plate V-32 on the top of the crystal nucleus responder V-3; turn on the circulating water filter STN-2, the circulating water pump PU-2, the first valve 1, the second valve 2, the sixth valve 6, the eighth valve 8 and the thirteenth valve 13, so that the heated circulating water enters the slurry pre-separation tank V-1 jacket, the solution receiving tank V-2 jacket and the crystal nucleus responder V-3 jacket respectively, so that the slurry pre-separation tank V-1, the solution receiving tank V-2, and the crystal nucleus responder V-3 are preheated to 74°C.

[0085] (3) Nucleus responder lead-in;

[0086] Open the combined filter STN-1, the slurry delivery pump PU-1 and the third valve 3, introduce the industrial ammonium sulfate slurry into the slurry pre-separation tank V-1, use the first agitator V-11 to stir the industrial ammonium sulfate slurry in the slurry pre-separation tank V-1 to stabilize the temperature, and the stirring rate range is 150r / min. When the temperature stabilizes to 74°C, stop stirring and let it stand for 8 minutes to pre-precipitate ammonium sulfate solid. The industrial ammonium sulfate slurry with a low solid content in the upper part is filtered through the combined filter STN-1 to remove impurities and ammonium sulfate crystals, and then the ammonium sulfate solids and particulate impurities are separated to obtain a saturated ammonium sulfate solution with low impurity content and high transparency. The saturated ammonium sulfate solution is pumped to the solution receiving tank V-2 with a temperature of 74°C by the slurry delivery pump PU-1, and is stirred by the second agitator V-21 at a constant temperature of 74°C, and the stirring rate range is 1 50r / min, and at the same time, the conductivity and temperature of the solution in the solution receiving tank V-2 are detected by the second infrared optical fiber monitoring probe CIR02 and the second infrared temperature monitoring probe TIR02, and the conductivity is converted into solution concentration, recorded as c0=0.464, and the temperature T0=74°C is recorded at this time; the fourth valve 4, the fifth valve 5, the twelfth valve 12 and the vacuum pumping equipment are opened, and the saturated ammonium sulfate solution in the solution receiving tank V-2 is slowly introduced into the two layers of staggered thermal sensitive trays on the upper part of the crystal nucleus responder V-3 under the negative pressure of the system to buffer the solution delivery pressure and avoid the error caused by splashing and hanging on the wall of the solution, until the solution fills the three groups of vertical hydrophobic thin tubes V-33 in the middle of the crystal nucleus responder V-3 and reaches the Y-type crystal nucleus main response area V-34 at the bottom of the crystal nucleus responder V-3, and the crystal nucleus responder V-3 is stopped to feed, and the constant temperature is maintained at 74°C. After the test, the tenth valve 10 of the crystal nucleus responder V-3 is opened to discharge the liquid through the liquid discharge port.

[0087] (4) Monitoring of crystal nucleation response;

[0088] Close the first valve 1, the eleventh valve 11 and the thirteenth valve 13, open the crystallization circulation water pump PU-3, open the natural cooling circulation process of the circulating water between the crystallization circulation water tank V-4 and the crystal nucleus responder V-3 jacket, and realize the slow natural cooling of the ambient temperature. The conductivity change inflection point of the first layer tower plate V-31 on the top of the crystal nucleus responder V-3 and the Y-type crystal nucleus main response area V-34 at the bottom of the crystal nucleus responder V-3 responds to the crystal nucleus formation, and the first online extended objective lens high-definition optical microscope intelligent comparison system YGR01 of the three groups of vertical hydrophobic thin tubes V-33 in the middle of the crystal nucleus responder V-3 and the second online extended objective lens high-definition optical microscope intelligent comparison system YGR02 of the Y-type crystal nucleus main response area V-34 assist in capturing the crystal nucleus formation transient, assist in responding to the crystal nucleus formation conductivity change inflection point, and record the temperature value T1 = 53.5 ° C of the crystal nucleus formation at the same time. The above parameters are displayed locally and centrally, and the computer collects real-time data and automatically forms a crystal nucleus response transient diagram.

[0089] (5) Mapping of the crystallization metastable zone;

[0090] Repeat the above steps (1) to (4) for many times under the condition of a temperature of 74°C and record the obtained parameters. Draw a solubility curve according to the temperature and conductivity-converted concentration of the saturated ammonium sulfate solution in the solution receiving tank V-2. According to the conductivity change inflection point of the first layer tray V-31 on the upper part of the crystal nucleus responder V-3, the Y-shaped crystal nucleus main response area V-34 on the lower part of the crystal nucleus responder V-3 and the corresponding temperature T1 and the crystal nucleus response transient diagram, as shown in FIG. Figure 2 As shown, a super solubility curve is drawn, and the curve between the solubility curve and the super solubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

[0091] Example 2

[0092] This embodiment is the same as embodiment 1, except that: 0＝ 55℃,c 0＝ 0.440g / g, T 1＝ 31.5℃.

[0093] Example 3

[0094] This embodiment is the same as embodiment 1, except that: 0＝ 59℃,c 0＝ 0.444g / g, T 1＝ 33.5℃.

[0095] Example 4

[0096] This embodiment is the same as embodiment 1, except that: 0＝ 62℃,c 0＝ 0.446g / g, T 1＝ 34.5℃.

[0097] Example 5

[0098] This embodiment is the same as embodiment 1, except that: 0＝ 65℃,c 0＝ 0.452g / g, T 1＝ 38.5℃.

[0099] Example 6

[0100] This embodiment is the same as embodiment 1, except that: 0＝ 68℃,c 0＝ 0.456g / g, T 1＝ 41.2℃.

[0101] Example 7

[0102] This embodiment is the same as embodiment 1, except that: 0＝ 70℃,c 0＝ 0.458g / g, T 1＝ 43.0℃.

[0103] Example 8

[0104] This embodiment is the same as embodiment 1, except that: 0＝ 78℃,c 0＝ 0.470g / g, T 1＝ 62.5℃.

[0105] Example 9

[0106] This embodiment is the same as embodiment 1, except that: 0＝ 80℃,c 0＝ 0.476g / g, T 1＝ 75.0℃.

[0107] Example 10

[0108] This embodiment is the same as embodiment 1, except that: 0＝ 82℃,c 0＝ 0.481g / g, T 1＝ 79.0℃.

[0109] The summary results of T0, c0, and T1 data in Examples 1 to 10 are shown in Table 1. The solubility curve, super solubility curve, and the crystallization metastable zone of the industrial ammonium sulfate slurry crystal system between the two curves are shown in Table 1. Figure 3 shown.

[0110] Table 1 Crystallization metastable zone parameters of industrial ammonium sulfate slurry crystallization system

[0111] Serial number <![CDATA[T0 / ℃]]> <![CDATA[c0 / (g / g)]]> <![CDATA[T1 / ℃]]> 1 74 0.464 53.5 2 55 0.440 31.5 3 59 0.444 33.5 4 62 0.446 34.5 5 65 0.452 38.5 6 68 0.456 41.2 7 70 0.458 43.0 8 78 0.470 62.5 9 80 0.476 75.0 10 82 0.481 79.0

[0112] The present invention discloses a method and system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system by an image-assisted conductivity method. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The products of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the products described herein without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

Claims

1. A system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method, characterized in that: It includes slurry pre-dividing tank, solution receiving tank, crystal nucleus responder, crystallization circulating water tank, slurry delivery pump, circulating water pump, crystallization circulating water pump, combined filter, circulating water filter, circulating water heater, first valve to thirteenth valve, vacuum equipment; The circulating water heater is connected to the circulating water filter; the circulating water filter is connected to the circulating water pump; the circulating water pump is connected to the slurry pre-dividing tank jacket through the second valve, and the circulating water pump is connected to the crystal nucleus responder jacket through the first valve; the slurry pre-dividing tank is connected to the combined filter; the combined filter is connected to the slurry delivery pump; the slurry delivery pump is connected to the solution receiving tank through the third valve; the slurry pre-dividing tank is connected to the solution receiving tank jacket through the eighth valve, the solution receiving tank is connected to the vacuum pumping device through the fourth valve, the solution receiving tank is connected to the crystal nucleus responder through the fifth valve, and the solution receiving tank jacket is connected to the circulating water heater through the sixth valve; the crystal nucleus responder is connected to the vacuum pumping device through the twelfth valve, the crystal nucleus responder jacket is connected to the circulating water heater through the thirteenth valve, and the crystal nucleus responder jacket is connected to the crystallization circulating water tank; the crystallization circulating water tank is connected to the circulating water heater through the eleventh valve, the ninth valve, the seventh valve and the sixth valve; the crystallization circulating water tank is connected to the crystallization circulating water pump; the crystallization circulating water pump is connected to the circulating water heater through the ninth valve and the seventh valve; A first agitator is installed in the slurry pre-separation tank, and a first infrared optical fiber monitoring probe and a first infrared temperature monitoring probe are placed on the upper end of the first agitator; A second agitator is installed in the solution receiving tank, and a second infrared optical fiber monitoring probe and a second infrared temperature monitoring probe are placed on the upper end of the second agitator; The upper part of the crystal core responder is provided with two layers of staggered distribution of thermal sensitive trays, namely the first layer tray and the second layer tray, a third infrared optical fiber monitoring probe and a third infrared temperature monitoring probe are placed on the first layer tray, and a fourth infrared optical fiber monitoring probe and a fourth infrared temperature monitoring probe are placed on the second layer tray; The central part of the crystal core responder is provided with three groups of vertical hydrophobic thin tubes, and a first online extended objective lens high-definition optical microscope intelligent comparison system is placed on the three groups of vertical hydrophobic thin tubes; The lower part of the crystal core responder is provided with a Y-shaped crystal core main response area, and a second online extended objective lens high-definition optical microscope intelligent comparison system and a fifth infrared optical fiber monitoring probe are placed in the Y-shaped crystal core main response area; The bottom of the crystal core responder is also provided with a tenth valve and a liquid discharge port; A sixth infrared temperature monitoring probe is placed in the crystallization circulating water tank; A fifth infrared temperature monitoring probe is placed in the circulating water heater.

2. The system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 1, characterized in that: It also includes an intelligent temperature control system, which is respectively connected to the first infrared temperature monitoring probe, the second infrared temperature monitoring probe, the third infrared temperature monitoring probe, the fourth infrared temperature monitoring probe, the fifth infrared temperature monitoring probe and the sixth infrared temperature monitoring probe; the intelligent temperature control system is used to accurately record the operating temperature of each module according to industrial crystallization conditions using an integrated display control method, and quickly respond to crystal nucleus formation.

3. A method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method, characterized in that: The system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method as described in claim 1 or 2 is implemented, and the method comprises the following steps: (1) System temperature rise; Turn on the circulating water heater and set the heating temperature, turn on the circulating water filter, circulating water pump, the first valve, the second valve, the sixth valve, the eighth valve and the thirteenth valve, the heated circulating water passes through the circulating water filter, the circulating water pump, the second valve in turn into the slurry pre-separation tank jacket, then from the slurry pre-separation tank jacket through the eighth valve into the solution receiving tank jacket, and from the solution receiving tank jacket through the sixth valve back to the circulating water heater; the circulating water passes through the circulating water filter, the circulating water pump, the first valve in turn into the crystal nucleus responder jacket, and then from the crystal nucleus responder jacket through the thirteenth valve back to the circulating water heater, so that the slurry pre-separation tank, the solution receiving tank, and the crystal nucleus responder are preheated to 35-95°C; (2) Nucleus responder lead; Open the combined filter, the slurry delivery pump and the third valve, introduce the industrial ammonium sulfate slurry into the slurry pre-separation tank, stir the industrial ammonium sulfate slurry in the slurry pre-separation tank with the first agitator, and when the temperature stabilizes to 35-95°C, stop stirring and let it stand for 5-10 minutes to pre-precipitate ammonium sulfate solid. The industrial ammonium sulfate slurry with low solid content in the upper part is filtered through the combined filter to remove impurities and ammonium sulfate crystals, and then the ammonium sulfate solid and particulate impurities are separated to obtain a saturated ammonium sulfate solution with low impurity content and high transparency. The saturated ammonium sulfate solution is pumped to a solution receiving tank with a temperature of 35-95°C by a slurry delivery pump and is heated to 35-95°C. Use the second stirrer to stir under the constant temperature condition, and convert the solution conductivity in the solution receiving tank into solution concentration, recorded as c0, and record the temperature T0 at this time; open the fourth valve, the fifth valve, the twelfth valve and the vacuum equipment, and slowly introduce the saturated ammonium sulfate solution in the solution receiving tank into the two layers of staggered thermal-sensitive tower plates on the upper part of the crystal core responder under the negative pressure of the system, until the solution fills the three groups of vertical hydrophobic thin tubes in the middle of the crystal core responder and reaches the Y-shaped crystal core main response area at the lower part of the crystal core responder, stop the crystal core responder from feeding, maintain a constant temperature of 35-95°C, and after the test, open the tenth valve of the crystal core responder to discharge the liquid through the liquid discharge port; (3) Monitoring of crystal nucleation response; Close the first valve, the eleventh valve and the thirteenth valve, start the crystallization circulation water pump, open the natural cooling circulation process of the circulating water between the crystallization circulation water tank and the crystal nucleus responder jacket, and realize the slow natural cooling of the ambient temperature; the conductivity change inflection point of the first layer of tower plate on the upper part of the crystal nucleus responder and the Y-shaped crystal nucleus main response area at the lower part of the crystal nucleus responder responds to the crystal nucleus formation, and the first online extended objective lens high-definition optical microscope intelligent comparison system of the three groups of vertical hydrophobic thin tubes in the middle of the crystal nucleus responder and the second online extended objective lens high-definition optical microscope intelligent comparison system of the Y-shaped crystal nucleus main response area assist in capturing the crystal nucleus formation transient, assist in responding to the conductivity change inflection point of the crystal nucleus formation, and record the temperature value T1 of the crystal nucleus formation at the same time, and the computer collects real-time data and automatically forms a crystal nucleus response transient diagram; (4) Mapping of the crystallization metastable zone; The above steps are repeated multiple times at 35-95°C and the obtained parameters are recorded. A solubility curve is drawn according to the temperature of the saturated ammonium sulfate solution in the solution receiving tank and the concentration converted from the conductivity. A super solubility curve is drawn according to the conductivity change inflection point of the first layer of tower plate on the upper part of the crystal nucleus responder and the Y-type crystal nucleus main response area at the lower part of the crystal nucleus responder, the corresponding temperature T1 and the crystal nucleus response transient diagram. The curve between the solubility curve and the super solubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

4. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: In step (1), the circulating water heater is turned on and the heating temperature is set to 30-100°C.

5. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: In step (1), deionized water is used as a standard solution to calibrate the conductivity measurement points of the circulating water in the slurry pre-separation tank, the solution receiving tank and the second layer of the tower plate on the upper part of the crystal nucleus responder.

6. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: In step (1), circulating water from a circulating water heater is circulated between the slurry pre-separation tank, the solution receiving tank, the crystal nucleus responder, the crystallization circulating water tank and the circulating water heater to simulate the temperature of the ammonium sulfate slurry / solution under industrial crystallization conditions.

7. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: In step (2), the industrial ammonium sulfate slurry is stirred in the slurry pre-separation tank by using a first stirrer, and the stirring rate ranges from 40 to 400 r / min.

8. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: In step (2), stirring is performed using a second stirrer at a constant temperature of 35 to 95° C., with a stirring rate ranging from 40 to 300 r / min.

9. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: In step (2), saturated ammonium sulfate solution is used as a standard solution to calibrate the conductivity measurement points of the solution in the first layer of the upper tray and the lower Y-shaped crystal core main response area of ​​the crystal core responder.

10. The method for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystal system using an image-assisted conductivity method according to claim 3, characterized in that: The temperature of the circulating water in the circulating water heater is detected by the fifth infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the industrial ammonium sulfate slurry in the slurry pre-separation tank are detected by the first infrared optical fiber monitoring probe and the first infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the solution receiving tank are detected by the second infrared optical fiber monitoring probe and the second infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the first layer of the tower plate on the upper part of the crystal nucleus responder are detected by the third infrared optical fiber monitoring probe and the third infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the second layer of the tower plate on the upper part of the crystal nucleus responder are detected by the fourth infrared optical fiber monitoring probe and the fourth infrared temperature monitoring probe; the conductivity of the circulating water and the solution in the Y-shaped crystal nucleus main response area at the lower part of the crystal nucleus responder is detected by the fifth infrared optical fiber monitoring probe; the temperature of the circulating water in the crystallization circulating water tank is detected by the sixth infrared temperature monitoring probe.

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