A method and system for monitoring the metastable zone of a crystallization system with high impurity content and low light transmittance by image method assisted conductivity method

Abstract

The application discloses a method and system for monitoring a crystallization metastable zone of a high-impurity and low-transmittance crystallization system by means of an image method and an on-line conductivity method, and belongs to the field of industrial crystallization data testing.The system comprises a slurry pre-separation tank, a solution receiving tank, a crystal nucleus response device, 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, a first valve to a thirteenth valve and a vacuumizing device.The application can quickly respond to crystal nucleus formation, improve the reliability and repeatability of crystallization metastable zone data determination, guide AMASOX, GE and NKK and other ammonia desulfurization by-products of ammonium sulfate to form moderate nucleation in the crystallization metastable zone, generate large-sized crystals, and be beneficial to centrifuge separation of the ammonium sulfate crystals.The application not only improves the ammonia desulfurization efficiency, but also produces high-quality ammonium sulfate from SO2 in the sulfur-containing flue gas, and has certain economic benefits and environmental protection benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of industrial crystallization data testing, and particularly relates to a method and system for online monitoring of a crystallization metastable zone of a high-impurity-containing and low-transmittance crystallization system by means of an image method assisted conductivity method. BACKGROUND

[0002] Ammonium sulfate is a quick-acting and biological fertilizer, and is also a way of resource utilization of SO2 by ammonia desulfurization process commonly used in the steel and coal power industries. Currently, AMASOX ammonia method, GE ammonia method and NKK ammonia method are mainly used, but problems such as small (NH4)2SO4 crystal grains, centrifuge plugging and inability to separate exist in actual operation. In the industrial crystallization process, the ammonium sulfate solution system is controlled in the metastable zone between the supersaturation curve and the dissolution curve, so that explosive nucleation can be avoided, and the crystal growth is enabled. In addition, various impurities are introduced into the process due to flue gas, raw material ammonia water and equipment corrosion, including organic impurities such as oils and phenols, and inorganic impurities such as fly ash, Al 3 + , Fe 3+ , Cl - , etc., which makes the composition of the ammonium sulfate mother liquor complex and the transparency low, increasing the difficulty of determination of the ammonium sulfate solution crystallization metastable zone.

[0003] Currently, the main methods for determining the metastable zone of crystals are visual observation, Coulter counting and laser method. Visual observation is affected by human factors, and its accuracy and repeatability are unstable. The accuracy of Coulter counting and laser method is not high when measuring solutions with low transmittance, and the generation of crystal nucleus cannot be responded. Chinese patent CN102680511A discloses a method for online monitoring the solubility, metastable zone and solution concentration of an organic salt system during crystallization. The method can determine the solubility curve of the solute in the solvent according to the mutation point in the relationship curve between conductivity and temperature during the heating process, thereby determining the solubility of the solute in the solvent. The crystallization temperature of the system can be determined according to the mutation point in the relationship curve between conductivity and temperature during the cooling process, thereby obtaining the metastable zone of the solution system at the cooling rate. The coefficients in the formula are 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 measured is calculated. This method is not suitable for inorganic salt systems, which limits the application range of the method. Chinese patent CN110243825A discloses a method for measuring the solubility, supersolubility and solution concentration of a solution during crystallization based on online image method. The method can obtain the solubility of the solution according to the initial solid-liquid mass ratio and the crystal mass concentration difference determined by online image. The crystallization temperature of the solution system during the cooling process is determined according to the mutation point of the number of crystal particles, thereby obtaining the supersolubility curve and the metastable zone of the system. Chinese patent CN112162003A discloses a device and method for measuring the crystallization metastable zone width of a micro-scale flow system. The measured solution with a temperature of the initial test temperature and reaching a saturated state at the initial test temperature is injected into a microchannel at a constant flow rate by a syringe pump. The microchannel is magnified by a microscope, and the measured liquid in the microchannel is photographed in real time by a camera to capture the crystallization state of the fluid and obtain the crystallization point temperature. The difference between the initial test temperature and the crystallization point temperature is calculated, which is the crystallization metastable zone width of the measured solution in the micro-scale flow system. Chinese patent CN101788464A discloses an online detection method and special device for solution concentration during dissolution crystallization. The sample is filtered to remove crystal particles in the solution by a sampling tube with a microfilter at the front end, then continuously extracted from the crystallization kettle by a sampling pump and sent to a detection cell. The ultraviolet absorption spectrum of the solution in the detection cell is recorded continuously by an ultraviolet fiber spectrometer and transmitted to a computer for real-time recording. The measured solution flows back to the crystallization kettle. The orthogonal signal correction (OSC) method is used to correct the continuously recorded ultraviolet detection spectrum in the computer, and then the absorbance value at any wavelength in the ultraviolet region of 200-400 nm is taken. The calculation coefficient in the Lambert-beer calculation formula is calculated by the least squares method, and then the solute concentration of the measured solution at a certain time is calculated. The above three methods all have the problem of low accuracy when measuring solutions with low transmittance.A method for determining the metastable zone of a high-concentration, low-transmittance solution system responsive to a microporous membrane is disclosed in Chinese patent CN104502222A. The solution to be measured is added to a crystallization kettle, and the solution to be measured is circulated. The temperature, stirring, and circulation pump flow rate in the crystallization kettle are kept stable. The vapor that passes through the membrane returns to the solvent tank with the cooled circulating solvent. The solvent that passes through the membrane is weighed and converted into a distillation rate. The concentration of the solution to be measured at each time is obtained by the total mass of the solvent distilled at each time. The inflection point of the distillation rate is the nucleation time of the crystals. At this time, the concentration of the solution to be measured is the spontaneous nucleation concentration under the operating conditions. The difference between the spontaneous nucleation concentration and the saturation concentration of the solution to be measured is the metastable zone width of the solution system under the operating conditions. This method has the following problems: When the ammonium sulfate solution contains many impurities, the microporous membrane material is blocked, and the evaporation rate decreases, which causes the formation of small crystal nuclei and false images, resulting in a narrow metastable zone width.

[0004] It can be seen that the existing determination methods generally have low determination accuracy for low transmittance and high-impurity crystallization systems. Therefore, a measurement method with wide adaptability and high accuracy is needed, especially for the determination of the crystallization metastable zone of an industrial crystallization system with many impurities and low transmittance. SUMMARY

[0005] To solve the problems of low determination accuracy, inapplicability to inorganic salt systems, and narrow application range of the existing determination methods for the crystallization metastable zone of a crystallization system, the present application provides a method and system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystallization system assisted by an image method and an electrical conductivity method.

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

[0007] The system for online monitoring of the crystallization metastable zone of a high-impurity, low-transmittance crystallization system assisted by an image method and an electrical conductivity method provided by the present application comprises a slurry pre-separation tank, a solution receiving tank, a crystal nucleus response device, 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, first to thirteenth valves, and a vacuum pumping device.

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

[0009] A first agitator is installed in the slurry pre-division tank, and a first infrared optical fiber monitoring probe and a first infrared temperature monitoring probe are arranged in 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 arranged in the upper end of the second agitator.

[0011] Two layers of staggered distribution heat-sensitive trays, i.e., a first layer of tray and a second layer of tray, are arranged in the upper part of the crystal nucleus responder, a third infrared optical fiber monitoring probe and a third infrared temperature monitoring probe are arranged on the first layer of tray, and a fourth infrared optical fiber monitoring probe and a fourth infrared temperature monitoring probe are arranged on the second layer of tray;

[0012] Three groups of vertical hydrophobic fine column tubes are arranged in the middle part of the crystal nucleus responder, and a first online extended objective lens high-definition optical microscope intelligent contrast system is arranged on the three groups of vertical hydrophobic fine column tubes;

[0013] A Y-shaped crystal nucleus main response area is arranged in the lower part of the crystal nucleus responder, and a second online extended objective lens high-definition optical microscope intelligent contrast system and a fifth infrared optical fiber monitoring probe are arranged in the Y-shaped crystal nucleus main response area;

[0014] A tenth valve and a liquid discharge port are further arranged in the bottom of the crystal nucleus responder;

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

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

[0017] Further, the application also comprises an intelligent temperature control system connected with the first, second, third, fourth, fifth and sixth infrared temperature monitoring probes respectively; the intelligent temperature control system is used for accurately recording the operating temperature of each module and quickly responding to the formation of crystal nucleus according to the industrial crystallization conditions by adopting the cluster display control mode.

[0018] The application provides a method for monitoring a crystallization metastable zone of a high-impurity and low-transmittance crystallization system by using an image method assisted conductivity method, and a system for monitoring a crystallization metastable zone of a high-impurity and low-transmittance crystallization system by using an image method assisted conductivity method.

[0019] (1) System temperature rising;

[0020] The circulating water heater is started and the heating temperature is set, the circulating water filter, the circulating water pump, the first valve, the second valve, the sixth valve, the eighth valve and the thirteenth valve are started, the heated circulating water passes through the circulating water filter, the circulating water pump and the second valve in sequence, enters the slurry pre-division tank jacket, and then flows back to the circulating water heater from the slurry pre-division tank jacket through the eighth valve and from the solution receiving tank jacket through the sixth valve; the circulating water passes through the circulating water filter, the circulating water pump and the first valve in sequence, enters the crystal nucleus responder jacket, and then flows back to the circulating water heater from the crystal nucleus responder jacket through the thirteenth valve, so that the slurry pre-division tank, the solution receiving tank and the crystal nucleus responder are preheated to 35-95 DEG C.

[0021] (2) Crystal nucleus responder material introduction;

[0022] Open the combined filter, slurry delivery pump and the third valve, industrial ammonium sulfate slurry is introduced into the slurry pre-distribution tank, the first agitator is used to stir the industrial ammonium sulfate slurry in the slurry pre-distribution tank, when the temperature is stable to 35-95℃, stop stirring and stand for 5-10min to pre-precipitate ammonium sulfate solid, the upper part of the industrial ammonium sulfate slurry with low solid content is filtered and impurities and ammonium sulfate crystals are removed after separating ammonium sulfate solid and particulate impurities, to obtain a saturated ammonium sulfate solution with low impurities and high transparency, the saturated ammonium sulfate solution is pumped to the solution receiving tank with a temperature of 35-95℃ by the slurry delivery pump, and is stirred by the second agitator under the condition of constant temperature with a temperature of 35-95℃, and the solution conductivity in the solution receiving tank is converted into the solution concentration, denoted as c0, and the temperature T0 at this time is recorded; open the fourth valve, the fifth valve, the twelfth valve and the vacuum pumping equipment, slowly introduce the saturated ammonium sulfate solution in the solution receiving tank into the upper two layers of staggered distribution heat-sensitive trays of the crystal nucleus response device under the negative pressure of the system, until the solution fills the middle three groups of vertical hydrophobic fine column tubes of the crystal nucleus response device and reaches the lower Y-shaped crystal nucleus main response area of the crystal nucleus response device, stop introducing the solution into the crystal nucleus response device, keep the constant temperature of 35-95℃, complete the test, open the tenth valve of the crystal nucleus response device to discharge the solution through the discharge port.

[0023] (3) Crystal nucleus formation response monitoring;

[0024] Close the first valve, the eleventh valve and the thirteenth valve, open the crystallization circulating water pump, and pass through the circulating water natural cooling circulation process between the crystallization circulating water tank and the jacket of the crystal nucleus response device to realize slow natural cooling of the environment; the conductivity change inflection point of the upper first layer of trays of the crystal nucleus response device and the lower Y-shaped crystal nucleus main response area of the crystal nucleus response device responds to the formation of crystal nucleus, and the first online extended objective lens high-definition optical microscope intelligent contrast system of the three groups of vertical hydrophobic fine column tubes in the middle of the crystal nucleus response device and the second online extended objective lens high-definition optical microscope intelligent contrast system of the Y-shaped crystal nucleus main response area assist in capturing the crystal nucleus formation transient state, assisting in responding to the conductivity change inflection point of the crystal nucleus formation, and recording the temperature value T1 of the crystal nucleus formation, and the computer collects real-time data and automatically forms a crystal nucleus response transient state diagram.

[0025] (4) Crystallization metastable zone mapping;

[0026] Repeat the above steps several times at 35-95℃ 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, draw an oversolubility curve according to the conductivity change inflection point of the upper first layer of trays of the crystal nucleus response device, the lower Y-shaped crystal nucleus main response area of the crystal nucleus response device, the corresponding temperature T1 and the crystal nucleus response transient state diagram, and the curve between the solubility curve and the oversolubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

[0027] Further, in step (1), the circulating water heater is started and the heating temperature is set to 30-100 DEG C.

[0028] Further, in step (1), the conductivity measuring points of the circulating water in the slurry pre-distributing tank, the solution receiving tank and the second layer of the upper part of the crystal nucleus response device are calibrated with deionized water as the standard solution.

[0029] Further, in step (1), the circulating water from the circulating water heater is circulated between the slurry pre-distributing tank, the solution receiving tank, the crystal nucleus response device, the crystallization circulating water tank and the circulating water heater to simulate the temperature of the ammonium sulfate slurry / solution under the industrial crystallization condition.

[0030] Further, in step (2), the industrial ammonium sulfate slurry is stirred in the slurry pre-distributing tank by the first stirrer, and the stirring rate is 40-400 r / min.

[0031] Further, in step (2), the second stirrer is used to stir under the constant temperature condition of 35-95 DEG C, and the stirring rate is 40-300 r / min.

[0032] Further, in step (2), the conductivity measuring points of the solution in the first layer of the upper part of the crystal nucleus response device and the Y-shaped crystal nucleus main response area of the lower part are calibrated with the saturated ammonium sulfate solution as the standard solution.

[0033] Further, 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-distributing tank are detected by the first infrared 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 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 upper part of the crystal nucleus response device are detected by the third infrared 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 upper part of the crystal nucleus response device are detected by the fourth infrared 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 of the lower part of the crystal nucleus response device are detected by the fifth infrared 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 application are:

[0035] The application combines the wet desulfurization process and the crystallization metastable zone determination technology to 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 and low-transmittance crystallization system by means of the image method assisted by the conductivity method, so as to quickly respond to the crystal nucleus formation, improve the reliability and repeatability of the determination of the crystallization metastable zone data, guide the moderate nucleation of the ammonium sulfate by-product of the ammonia desulfurization of AMASOX, GE and NKK in the crystallization metastable zone, generate crystals with a larger particle size, and be beneficial to the separation of the ammonium sulfate crystals by the centrifuge. The application not only improves the ammonia desulfurization efficiency, but also produces high-quality ammonium sulfate from SO2 in the sulfur-containing flue gas, and has certain economic and environmental benefits. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 A flowchart of a method (CGMZ) for online monitoring of the crystallization metastable zone of a high-impurity and low-transmittance crystallization system by means of the image method assisted by the conductivity method.

[0037] Figure 2 An online intelligent contrast system of the high-definition optical microscope assisted by the objective lens is used to capture the transient graph of the crystal nucleus formation.

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

[0039] The application will be further described in detail below with reference to the drawings.

[0040] In a first aspect, the application provides a method for online monitoring of the crystallization metastable zone of a high-impurity and low-transmittance crystallization system by means of the image method assisted by the conductivity method.

[0041] The method (CGMZ) for online monitoring of the crystallization metastable zone of a high-impurity and low-transmittance crystallization system by means of the image method assisted by the conductivity method is especially suitable for the determination of the crystal nucleation response and the metastable zone of the high-impurity and low-transmittance industrial ammonium sulfate slurry crystallization system, and the specific implementation process is as follows:

[0042] (1) System building;

[0043] According to Figure 1The test system is built in a connection mode, and mainly comprises: a slurry pre-distribution tank V-1, a solution receiving tank V-2, a crystal nucleus response device 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 combined filter STN-1, a circulating water filter STN-2, a circulating water heater HEAT-1, a first infrared optical fiber monitoring probe CIR01, a second infrared optical fiber monitoring probe CIR02, a third infrared optical fiber monitoring probe CIR03, a fourth infrared optical fiber monitoring probe CIR04, a fifth infrared optical fiber 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 online extended objective lens high-definition optical microscope intelligent comparison system YGR01, a second online extended objective lens high-definition optical microscope intelligent comparison system YGR02, first to thirteenth valves 1-13, a vacuumizing device and an intelligent temperature control system.

[0044] The first agitator V-11 is arranged in the slurry pre-distribution tank V-1, and the first infrared optical fiber monitoring probe CIR01 and the first infrared temperature monitoring probe TIR01 are arranged in the upper end of the first agitator V-11.

[0045] The second agitator V-21 is arranged in the solution receiving tank V-2, and the second infrared optical fiber monitoring probe CIR02 and the second infrared temperature monitoring probe TIR02 are arranged in the upper end of the second agitator V-21.

[0046] The two layers of staggered distribution heat-sensitive trays (the first layer of tray V-31 and the second layer of tray V-32) are arranged in the upper part of the crystal nucleus response device V-3, the third infrared optical fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03 are arranged on the first layer of tray V-31, and the fourth infrared optical fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04 are arranged on the second layer of tray V-32; the three groups of vertical hydrophobic fine column pipes V-33 are arranged in the middle part of the crystal nucleus response device V-3, and the first online extended objective lens high-definition optical microscope intelligent comparison system YGR01 is arranged on the three groups of vertical hydrophobic fine column pipes V-33; the Y-shaped crystal nucleus main response area V-34 is arranged in the lower part of the crystal nucleus response device 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 arranged in the Y-shaped crystal nucleus main response area V-34; the tenth valve 10 and the liquid discharge port are further arranged at the bottom of the crystal nucleus response device V-3.

[0047] The sixth infrared temperature monitoring probe TIR06 is arranged in the crystallization circulating water tank V-4.

[0048] The fifth infrared temperature monitoring probe TIR05 is arranged in the circulating water heater HEAT-1.

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

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

[0051] In the application, the intelligent temperature control system is connected with 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 respectively. The intelligent temperature control system is mainly used for accurately recording the operation temperature of each module, responding to the crystal nucleus formation quickly and improving the reliability and repeatability of the crystallization metastable zone data measurement according to the industrial crystallization conditions.

[0052] (2) System temperature rise;

[0053] Before the system works, it should be ensured that the pipeline has no leakage point, the sealing performance is good, the instrument is intact, the power supply of the live equipment is completed, and the conductivity measuring point is corrected and ready for use.

[0054] The circulating water heater HEAT-1 is turned on and the heating temperature is set to 30-100°C, and the temperature of the circulating water is detected by the fifth infrared temperature monitoring probe TIR05 during the heating process; 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 are turned on, so that the heated circulating water enters the slurry pre-division tank V-1 jacket, the solution receiving tank V-2 jacket and the crystal nucleus response device V-3 jacket, respectively, specifically, the circulating water passes through the circulating water filter STN-2, the circulating water pump PU-2 and the second valve 2 in sequence, enters the slurry pre-division tank V-1 jacket, and then passes through the eighth valve 8 from the slurry pre-division tank V-1 jacket to enter the solution receiving tank V-2 jacket, and then flows back to the circulating water heater HEAT-1 from the solution receiving tank V-2 jacket through the sixth valve 6; the circulating water passes through the circulating water filter STN-2, the circulating water pump PU-2 and the first valve 1 in sequence, enters the crystal nucleus response device V-3 jacket, and then flows back to the circulating water heater HEAT-1 from the crystal nucleus response device V-3 jacket through the thirteenth valve 13, so that the slurry pre-division tank V-1, the solution receiving tank V-2 and the crystal nucleus response device V-3 are preheated to 35-95°C, and the conductivity and temperature of the circulating water in the slurry pre-division tank V-1 are detected by the first infrared fiber monitoring probe CIR01 and the first infrared temperature monitoring probe TIR01 during the heating process, the conductivity and temperature of the circulating water in the solution receiving tank V-2 are detected by the second infrared 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 trays V-31 at the upper part of the crystal nucleus response device V-3 are detected by the third infrared fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03, the conductivity and temperature of the circulating water in the second layer of trays V-32 at the upper part of the crystal nucleus response device V-3 are detected by the fourth infrared fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04, and the conductivity of the circulating water in the Y-shaped crystal nucleus main response area V-34 at the lower part of the crystal nucleus response device V-3 is detected by the fifth infrared fiber monitoring probe CIR05 at the same time, and the conductivity measuring points of the circulating water in the slurry pre-division tank V-1, the solution receiving tank V-2 and the second layer of trays V-32 at the upper part of the crystal nucleus response device V-3 are corrected with deionized water as a standard solution.

[0055] At this point, the circulating water from the circulating water heater HEAT-1 can circulate between the slurry pre-division tank V-1, the solution receiving tank V-2, the crystal nucleus response device 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) Crystal nucleus response device for introducing material;

[0057] The combined filter STN-1, the slurry delivery pump PU-1 and the third valve 3 are opened, the industrial ammonium sulfate slurry is introduced into the slurry pre-distribution tank V-1, and after stirring, heat preservation and pre-precipitation in the slurry pre-distribution tank V-1, a saturated ammonium sulfate slurry with a low solid content is obtained. Specifically, the first stirrer V-11 is used to stir the industrial ammonium sulfate slurry in the slurry pre-distribution tank V-1 to stabilize the temperature, and the stirring rate ranges from 40 to 400 r / min. Meanwhile, the first infrared optical fiber monitoring probe CIR01 and the first infrared temperature monitoring probe TIR01 are used to detect the conductivity and temperature of the industrial ammonium sulfate slurry in the slurry pre-distribution tank V-1. When the temperature is stabilized to 35-95℃, the stirring is stopped and the ammonium sulfate solid is pre-precipitated for 5-10 min. The upper industrial ammonium sulfate slurry with a low solid content is filtered and impurities and ammonium sulfate crystals are removed through the combined filter STN-1, and then the ammonium sulfate solid and particulate impurities are separated to obtain a saturated ammonium sulfate solution with low impurities and high transparency. The saturated ammonium sulfate solution is pumped to the solution receiving tank V-2 at a temperature of 35-95℃ by the slurry delivery pump PU-1, and is stirred at a temperature of 35-95℃ by the second stirrer V-21. The stirring rate ranges from 40 to 300 r / min. Meanwhile, the second infrared optical fiber monitoring probe CIR02 and the second infrared temperature monitoring probe TIR02 are used to detect the conductivity and temperature of the solution in the solution receiving tank V-2, and the conductivity is converted into the solution concentration, denoted as c0, and the temperature T0 at this time is recorded. 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 upper two layers of staggered distribution heat-sensitive trays (the first layer of trays V-31 and the second layer of trays V-32) in the crystal nucleus response device V-3 under the system negative pressure, so as to buffer the solution delivery pressure and avoid errors caused by the splashing and wall-hanging of the solution. Meanwhile, the third infrared optical fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03 are used to detect the conductivity and temperature of the solution in the first layer of trays V-31, and the fourth infrared optical fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04 are used to detect the conductivity and temperature of the solution in the second layer of trays V-32. Until the solution fills the three groups of vertical hydrophobic fine column tubes V-33 in the middle of the crystal nucleus response device V-3 and reaches the Y-shaped crystal nucleus main response area V-34 at the lower part of the crystal nucleus response device V-3, and the fifth infrared optical fiber monitoring probe CIR05 is used to detect the conductivity of the solution in the Y-shaped crystal nucleus main response area V-34. The material introduction of the crystal nucleus response device V-3 is stopped, and the temperature is kept at 35-95℃. After the test is completed, the tenth valve 10 of the crystal nucleus response device V-3 is opened to discharge the solution through the discharge port. The signals of all temperatures, conductivities and pump flow rates are centrally controlled and displayed, and the conductivity of the saturated ammonium sulfate solution in the solution receiving tank V-2 is converted into the concentration in real time, and the conductivity is displayed in real time.

[0058] (4) Crystal nucleus formation response monitoring;

[0059] Close the first valve 1, the eleventh valve 11 and the thirteenth valve 13, open the crystallization circulating water pump PU-3, and open the circulating water natural cooling circulation process between the crystallization circulating water tank V-4 and the jacket of the crystal nucleus response device V-3, so as to realize slow natural cooling of the ambient temperature, and 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 in the jacket of the crystal nucleus response device 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, and then the circulating water flows back to the circulating water heater HEAT-1 from the solution receiving tank V-2 through the eighth valve 8. The conductivity change inflection point of the first layer of trays V-31 on the upper part of the crystal nucleus response device V-3 and the Y-shaped crystal nucleus main response area V-34 on the lower part of the crystal nucleus response device V-3 responds to the formation of crystal nucleus, and the first online extended objective high-definition optical microscope intelligent contrast system YGR01 of the three groups of vertical hydrophobic fine columnar pipes V-33 in the middle part of the crystal nucleus response device V-3 and the second online extended objective high-definition optical microscope intelligent contrast system YGR02 of the Y-shaped crystal nucleus main response area V-34 assist in capturing the crystal nucleus formation transient state, and 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. The above parameters are displayed locally and centrally, and the computer collects real-time data and automatically forms a crystal nucleus response transient state diagram.

[0060] (5) Crystallization metastable zone mapping;

[0061] Repeat steps (1) to (4) above several times under the condition that the temperature is 35-95℃, and record the obtained parameters. According to the temperature and the concentration converted by the conductivity of the saturated ammonium sulfate solution in the solution receiving tank V-2, a solubility curve is drawn. According to the conductivity change inflection point of the first layer of trays V-31 on the upper part of the crystal nucleus response device V-3, the Y-shaped crystal nucleus main response area V-34 on the lower part of the crystal nucleus response device V-3, the corresponding temperature T1 and the crystal nucleus response transient state diagram, an oversolubility curve is drawn. The curve between the solubility curve and the oversolubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

[0062] In the present application, the conductivity measuring point of the slurry pre-distribution tank V-1, the solution receiving tank V-2 and the upper second layer tray V-32 of the crystal nucleus response device V-3 takes deionized water as the standard solution, and the conductivity measuring point of the solution in the upper first layer tray V-31 and the lower Y-shaped crystal nucleus main response area V-34 of the crystal nucleus response device V-3 takes saturated ammonium sulfate solution as the standard solution. The present application 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 in the crystal nucleus response device V-3 and the rapid response of the crystal nucleus formation.

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

[0064] The system for online monitoring of the crystallization metastable zone of a high-impurity and low-transmittance crystallization system by the image-assisted conductivity method provided in the present application mainly comprises a combined filtration system, a crystal nucleus response detection system and an intelligent temperature control system.

[0065] In the present application, the combined filtration system is graded with filter cloths and microporous membranes, which realizes the filtration of impurities with 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 application, the crystal nucleus response detection system mainly comprises a negative pressure feeding system, a crystal nucleus response monitoring system and an online extended objective high-definition optical microscope intelligent comparison system. The negative pressure feeding system is used to simulate the vacuum degree of the crystallization process of the system, the crystal nucleus response monitoring system is used to monitor the conductivity change inflection point and the corresponding temperature before and after the crystal nucleus response, and the online extended objective high-definition optical microscope intelligent comparison system is used to assist the formation of the transient state of the response crystal nucleus.

[0067] In the present application, the negative pressure feeding system mainly comprises a vacuumizing device, a first valve 4 and a twelfth valve 12.

[0068] In the application, the crystal nucleus response monitoring system mainly comprises: a slurry pre-distribution tank V-1, a solution receiving tank V-2, a crystal nucleus response device V-3, a crystallization circulating water tank V-4, a slurry conveying 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 optical fiber monitoring probe CIR01, a second infrared optical fiber monitoring probe CIR02, a third infrared optical fiber monitoring probe CIR03, a fourth infrared optical fiber monitoring probe CIR04, a fifth infrared optical fiber 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] The first agitator V-11 is arranged in the slurry pre-distribution tank V-1, and the first infrared optical fiber monitoring probe CIR01 and the first infrared temperature monitoring probe TIR01 are arranged in the upper end of the first agitator V-11.

[0070] The second agitator V-21 is arranged in the solution receiving tank V-2, and the second infrared optical fiber monitoring probe CIR02 and the second infrared temperature monitoring probe TIR02 are arranged in the upper end of the second agitator V-21.

[0071] The two layers of staggered distribution heat-sensitive trays (a first layer of trays V-31 and a second layer of trays V-32) are arranged in the upper part of the crystal nucleus response device V-3, the third infrared optical fiber monitoring probe CIR03 and the third infrared temperature monitoring probe TIR03 are arranged on the first layer of trays V-31, and the fourth infrared optical fiber monitoring probe CIR04 and the fourth infrared temperature monitoring probe TIR04 are arranged on the second layer of trays V-32; the three groups of vertical hydrophobic fine column pipes V-33 are arranged in the middle part of the crystal nucleus response device V-3, and the first online extended objective high-definition optical microscope intelligent comparison system YGR01 is arranged on the three groups of vertical hydrophobic fine column pipes V-33; the Y-shaped crystal nucleus main response area V-34 is arranged in the lower part of the crystal nucleus response device V-3, and the second online extended objective high-definition optical microscope intelligent comparison system YGR02 and the fifth infrared optical fiber monitoring probe CIR05 are arranged in the Y-shaped crystal nucleus main response area V-34; the tenth valve 10 and the liquid discharge port are further arranged at the bottom of the crystal nucleus response device V-3.

[0072] The sixth infrared temperature monitoring probe TIR06 is arranged in the crystallization circulating water tank V-4.

[0073] The fifth infrared temperature monitoring probe TIR05 is arranged in the circulating water heater HEAT-1.

[0074] In the application, the online extended objective high-definition optical microscope intelligent comparison system mainly comprises a first online extended objective high-definition optical microscope intelligent comparison system YGR01 and a second online extended objective high-definition optical microscope intelligent comparison system YGR02.

[0075] In the application, the intelligent temperature control system is mainly used for accurately recording the operation temperature of each module, responding to the formation of crystal nucleus quickly, and improving the reliability and repeatability of the determination of the metastable zone data of crystallization under the industrial crystallization conditions by adopting the display control mode.

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

[0077] The circulating water heater HEAT-1 is connected with the circulating water filter STN-2 through a pipeline; the circulating water filter STN-2 is connected with the circulating water pump PU-2 through a pipeline; the circulating water pump PU-2 is connected with the slurry pre-division tank V-1 jacket through a pipeline and the first valve 1, and is connected with the crystal nucleus responder V-3 jacket through a pipeline and the second valve 2; the slurry pre-division tank V-1 is connected with the combined filter STN-1 through a pipeline; the combined filter STN-1 is connected with the slurry delivery pump PU-1 through a pipeline; the slurry delivery pump PU-1 is connected with the solution receiving tank V-2 through a pipeline and the third valve 3; the slurry pre-division tank V-1 is connected with the solution receiving tank V-2 jacket through a pipeline and the eighth valve 8, the solution receiving tank V-2 is connected with the vacuumizing equipment through a pipeline and the fourth valve 4, the solution receiving tank V-2 is connected with the crystal nucleus responder V-3 through a pipeline and the fifth valve 5, and the solution receiving tank V-2 jacket is connected with the circulating water heater HEAT-1 through a pipeline and the sixth valve 6; the crystal nucleus responder V-3 is connected with the vacuumizing equipment through a pipeline and the twelfth valve 12, the crystal nucleus responder V-3 jacket is connected with the circulating water heater HEAT-1 through a pipeline and the thirteenth valve 13, the crystal nucleus responder V-3 jacket is connected with the crystallization circulating water tank V-4 through a pipeline, and the crystallization circulating water tank V-4 is connected with the circulating water heater HEAT-1 through a 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 with the crystallization circulating water pump PU-3 through a pipeline; the crystallization circulating water pump PU-3 is connected with the circulating water heater HEAT-1 through a pipeline, the ninth valve 9 and the seventh valve 7. The intelligent temperature control system is connected with 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 respectively.

[0078] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0079] Example 1

[0080] The present invention provides a method for online monitoring of the metastable region of a crystallization system with high impurity content and low transmittance using an image-assisted conductivity method. The specific implementation process is as follows:

[0081] (1) System setup;

[0082] according to Figure 1 The test system was built using the connection method. The system pipelines were leak-free and well-sealed. The instruments were in good working order. The live equipment was powered on and the conductivity measurement points were calibrated and ready for use.

[0083] (2) The system heats up;

[0084] Turn on the circulating water heater HEAT-1 and set the heating temperature to 74℃. During the heating process, the temperature of the circulating water is detected by the fifth infrared temperature monitoring probe TIR05. The conductivity measurement points of the slurry pre-separation tank V-1, solution receiving tank V-2, and the second tray V-32 on the upper part of the crystal nucleus responder V-3 are calibrated using deionized water as the standard solution. Turn on the circulating water filter STN-2, circulating water pump PU-2, first valve 1, second valve 2, sixth valve 6, eighth valve 8, and thirteenth valve 13 to allow the heated circulating water to enter the jackets of the slurry pre-separation tank V-1, solution receiving tank V-2, and crystal nucleus responder V-3, thereby preheating the slurry pre-separation tank V-1, solution receiving tank V-2, and crystal nucleus responder V-3 to 74℃.

[0085] (3) Nucleus responder lead;

[0086] Open the combined filter STN-1, slurry delivery pump PU-1 and the third valve 3, introduce the industrial ammonium sulfate slurry into the slurry pre-division tank V-1, and use the first agitator V-11 to stir the industrial ammonium sulfate slurry in the slurry pre-division tank V-1 to stabilize the temperature, the stirring rate ranges from 150 r / min, when the temperature is stabilized to 74℃, stop stirring and stand for 8 min to pre-precipitate ammonium sulfate solids, the upper part of the industrial ammonium sulfate slurry with lower solid content is filtered through the combined filter STN-1 to remove impurities and ammonium sulfate crystals, and then separates ammonium sulfate solids and particulate impurities 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 at a temperature of 74℃ by the slurry delivery pump PU-1, and is stirred at a constant temperature of 74℃ using the second agitator V-21, the stirring rate ranges from 150 r / min, 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 the solution concentration, denoted as c0=0.464, and the temperature at this time is recorded as T0=74℃; open the fourth valve 4, the fifth valve 5, the twelfth valve 12 and the vacuum pumping equipment, slowly introduce the saturated ammonium sulfate solution in the solution receiving tank V-2 into the upper two layers of staggered distribution heat-sensitive trays in the crystal nucleus response device V-3 under the system negative pressure, to buffer the solution delivery pressure and avoid errors caused by the solution splashing and hanging on the wall, until the solution fills the middle three groups of vertical hydrophobic fine column tubes V-33 in the crystal nucleus response device V-3 and reaches the Y-shaped crystal nucleus main response area V-34 at the lower part of the crystal nucleus response device V-3, stop introducing the solution into the crystal nucleus response device V-3, and keep the constant temperature at 74℃. After the test is completed, open the tenth valve 10 of the crystal nucleus response device V-3 to discharge the solution through the discharge port.

[0087] (4) Crystal nucleus formation response monitoring;

[0088] Close the first valve 1, the eleventh valve 11 and the thirteenth valve 13, open the crystallization circulating water pump PU-3, and open the circulating water natural cooling circulation process between the crystallization circulating water tank V-4 and the jacket of the crystal nucleus response device V-3 to achieve slow natural cooling of the environment. The conductivity change inflection point of the first layer of trays V-31 at the upper part of the crystal nucleus response device V-3 and the Y-shaped crystal nucleus main response area V-34 at the lower part of the crystal nucleus response device V-3 responds to the formation of crystal nucleus, and the first online extended objective high-definition optical microscope intelligent contrast system YGR01 of the three groups of vertical hydrophobic fine column tubes V-33 in the middle part of the crystal nucleus response device V-3 and the second online extended objective high-definition optical microscope intelligent contrast system YGR02 of the Y-shaped crystal nucleus main response area V-34 assist in capturing the crystal nucleus formation transient state, assisting in responding to the conductivity change inflection point of the crystal nucleus formation, and recording the temperature value T1=53.5℃ of the crystal nucleus formation, the above parameters are displayed locally and centrally, the computer collects real-time data and automatically forms a crystal nucleus response transient state diagram.

[0089] (5) Crystallization metastable zone mapping;

[0090] The above steps (1) to (4) were repeated several times at a temperature of 74°C and the parameters were recorded. The solubility curve was plotted according to the temperature and the concentration converted from the conductivity of the saturated ammonium sulfate solution in the solution receiving tank V-2. The supersolubility curve was plotted according to the conductivity change inflection point and the corresponding temperature T1 of the first layer of trays V-31 on the upper part of the crystal nucleus response device V-3, the Y-shaped crystal nucleus main response area V-34 on the lower part of the crystal nucleus response device V-3, and the crystal nucleus response transient diagram, as shown in Figure 2 The curve between the solubility curve and the supersolubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

[0091] Example 2

[0092] This example is the same as Example 1, except that T 0＝ 55°C, c 0＝ 0.440 g / g, T 1＝ 31.5°C.

[0093] Example 3

[0094] This example is the same as Example 1, except that T 0＝ 59°C, c 0＝ 0.444 g / g, T 1＝ 33.5°C.

[0095] Example 4

[0096] This example is the same as Example 1, except that T 0＝ 62°C, c 0＝ 0.446 g / g, T 1＝ 34.5°C.

[0097] Example 5

[0098] This example is the same as Example 1, except that T 0＝ 65°C, c 0＝ 0.452 g / g, T 1＝ 38.5°C.

[0099] Example 6

[0100] This example is the same as Example 1, except that T 0＝ 68°C, c 0＝ 0.456 g / g, T 1＝ 41.2°C.

[0101] Example 7

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

[0103] Example 8

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

[0105] Example 9

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

[0107] Example 10

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

[0109] The T0, c0, T1 data of the above examples 1-10 are shown in table 1, the solubility curve, the supersolubility curve and the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system between the two curves are shown in Figure 3 .

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

[0111] Serial Number [T0 / °C] [c0 / (g / g)] [T1 / °C] 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 application discloses a method and system for online monitoring of a crystallization metastable zone of a high-impurity-content and low-transmittance crystallization system by means of an image method and an electric conductivity method. Those skilled in the art can refer to the content of the application and appropriately improve process parameters. It should be particularly pointed out that all similar replacements and changes are obvious to those skilled in the art, and they are regarded as being included in the application. The product of the application has been described by means of a preferred embodiment, and relevant personnel can obviously make changes or appropriate changes and combinations to the product described in the application without departing from the content, spirit and scope of the application, so as to realize and apply the technical solution of the application.

Claims

1. A system for monitoring the metastable zone of a crystallization system with high impurity content and low light transmittance by image method assisted conductivity method, characterized in that, The slurry pre-distributing tank, the solution receiving tank, the crystal nucleus responder, the crystallization circulating water tank, the slurry delivery pump, the circulating water pump, the crystallization circulating water pump, the combined filter, the circulating water filter, the circulating water heater, the first valve to the thirteenth valve, the vacuumizing equipment are included. The circulating water heater is connected with the circulating water filter; the circulating water filter is connected with the circulating water pump; the circulating water pump is connected with the slurry pre-distributing tank jacket through the second valve, and the circulating water pump is connected with the crystal nucleus responder jacket through the first valve; the slurry pre-distributing tank is connected with the combined filter; the combined filter is connected with the slurry delivery pump; the slurry delivery pump is connected with the solution receiving tank through the third valve; the slurry pre-distributing tank is connected with the solution receiving tank jacket through the eighth valve, the solution receiving tank is connected with the vacuumizing equipment through the fourth valve, the solution receiving tank is connected with the crystal nucleus responder through the fifth valve, and the solution receiving tank jacket is connected with the circulating water heater through the sixth valve; the crystal nucleus responder is connected with the vacuumizing equipment through the twelfth valve, the crystal nucleus responder jacket is connected with the circulating water heater through the thirteenth valve, and the crystal nucleus responder jacket is connected with the crystallization circulating water tank; the crystallization circulating water tank is connected with 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 with the crystallization circulating water pump; the crystallization circulating water pump is connected with the circulating water heater through the ninth valve and the seventh valve. The first agitator is arranged in the slurry pre-distributing tank, and the first infrared optical fiber monitoring probe and the first infrared temperature monitoring probe are arranged in the upper end of the first agitator; The second agitator is arranged in the solution receiving tank, and the second infrared optical fiber monitoring probe and the second infrared temperature monitoring probe are arranged in the upper end of the second agitator; The upper part of the crystal nucleus responder is internally provided with two layers of staggered heat-sensitive trays, the heat-sensitive trays are composed of the first layer of tray and the second layer of tray, the third infrared optical fiber monitoring probe and the third infrared temperature monitoring probe are arranged on the first layer of tray, and the fourth infrared optical fiber monitoring probe and the fourth infrared temperature monitoring probe are arranged on the second layer of tray; The middle part of the crystal nucleus responder is internally provided with three groups of vertical hydrophobic fine pipe columns, and the first online extended objective high-definition optical microscope intelligent contrast system is arranged on the three groups of vertical hydrophobic fine pipe columns; The lower part of the crystal nucleus responder is provided with a Y-shaped crystal nucleus main response area, and the second online extended objective high-definition optical microscope intelligent contrast system and the fifth infrared optical fiber monitoring probe are arranged in the Y-shaped crystal nucleus main response area; The bottom of the crystal nucleus responder is further provided with the tenth valve and a liquid discharge port; The sixth infrared temperature monitoring probe is arranged in the crystallization circulating water tank; The fifth infrared temperature monitoring probe is arranged in the circulating water heater.

2. The system for monitoring the metastable zone of crystallization of a crystallization system with high impurity content and low light transmittance in line by image method assisted conductivity method according to claim 1, characterized in that, The intelligent temperature control system is connected with 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 respectively; the intelligent temperature control system is used for accurately recording the operation temperature of each module and quickly responding to the crystal nucleus formation according to the industrial crystallization conditions in a display control mode.

3. A method for monitoring the metastable zone of a crystallization system with high impurity content and low light transmittance by image method assisted conductivity method, characterized in that, The system for monitoring the metastable zone of a crystallization system with high impurities and low light transmittance by using the image method and the conductivity method according to claim 1 or 2, and the method comprises the following steps: (1) System temperature rising; Open the circulating water heater and set the heating temperature, open the circulating water filter, circulating water pump, first valve, second valve, sixth valve, eighth valve and thirteenth valve, the heated circulating water passes through the circulating water filter, circulating water pump, second valve into the slurry pre-division tank jacket in turn, and then passes through the eighth valve into the solution receiving tank jacket from the slurry pre-division tank jacket, and then flows back to the circulating water heater from the solution receiving tank jacket through the sixth valve; the circulating water passes through the circulating water filter, circulating water pump, first valve into the crystal nucleus response device jacket in turn, and then flows back to the circulating water heater from the crystal nucleus response device jacket through the thirteenth valve, so that the slurry pre-division tank, solution receiving tank and crystal nucleus response device are preheated to 35-95 DEG C; (2) Crystal nucleus response device material introduction; Open the combined filter, slurry conveying pump and third valve, introduce the industrial ammonium sulfate slurry into the slurry pre-division tank, and use the first stirrer to stir the industrial ammonium sulfate slurry in the slurry pre-division tank; when the temperature is stable at 35-95 DEG C, stop stirring and stand for 5-10 min to pre-precipitate ammonium sulfate solids; the upper industrial ammonium sulfate slurry with low solid content is filtered through the combined filter to remove impurities and ammonium sulfate crystals, and then ammonium sulfate solids and particulate impurities are separated, so that saturated ammonium sulfate solution with low impurities and high transparency is obtained; the saturated ammonium sulfate solution is pumped to the solution receiving tank with a temperature of 35-95 DEG C by the slurry conveying pump, and is stirred by the second stirrer under the condition of constant temperature with a temperature of 35-95 DEG C; the solution conductivity in the solution receiving tank is converted into solution concentration, which is denoted as c0, and the temperature T0 at this time is recorded; open the fourth valve, fifth valve, twelfth valve and vacuumizing equipment, slowly introduce the saturated ammonium sulfate solution in the solution receiving tank into the upper two layers of staggered distribution heat-sensitive trays of the crystal nucleus response device under the negative pressure of the system, until the solution fills the middle three groups of vertical hydrophobic fine column tubes of the crystal nucleus response device and reaches the lower Y-shaped crystal nucleus main response area of the crystal nucleus response device, stop the crystal nucleus response device material introduction, keep the constant temperature at 35-95 DEG C, complete the test, and open the tenth valve of the crystal nucleus response device to discharge the solution through the unloading port; (3) Crystal nucleus formation response monitoring; Close the first valve, eleventh valve and thirteenth valve, open the crystallization circulating water pump, and open the circulating water natural cooling circulation process between the crystallization circulating water tank and the crystal nucleus response device jacket to realize slow natural cooling of the environment; the conductivity change inflection point of the upper first layer of trays of the crystal nucleus response device and the lower Y-shaped crystal nucleus main response area of the crystal nucleus response device responds to the crystal nucleus formation, the first online extended objective lens high-definition optical microscope intelligent comparison system of the middle three groups of vertical hydrophobic fine column tubes of the crystal nucleus response device 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 state, assist in responding to the conductivity change inflection point of the crystal nucleus formation, record the temperature value T1 of the crystal nucleus formation, and the computer collects real-time data and automatically forms a crystal nucleus response transient state diagram. (4) crystallization metastable zone mapping; The above steps are repeated several times at 35-95℃, and the concentration converted from the temperature and conductivity of the saturated ammonium sulfate solution in the solution receiving tank is recorded to draw a solubility curve. The conductivity change inflection point and corresponding temperature T1 of the upper first layer tray of the crystal nucleus response device and the Y-shaped crystal nucleus main response area of the lower part of the crystal nucleus response device and the crystal nucleus response transient diagram are used to draw a supersolubility curve. The curve between the solubility curve and the supersolubility curve is the crystallization metastable zone of the industrial ammonium sulfate slurry crystallization system.

4. The method according to claim 3, wherein the method is characterized in that, In step (1), turn on the circulating water heater and set the heating temperature to 30-100℃.

5. The method according to claim 3, wherein the method is characterized in that, In step (1), use deionized water as a standard solution to calibrate the conductivity measuring points of the circulating water in the slurry pre-distribution tank, the solution receiving tank, and the upper second layer tray of the crystal nucleus response device.

6. The method according to claim 3, wherein the method is characterized in that, In step (1), the circulating water from the circulating water heater circulates between the slurry pre-distribution tank, the solution receiving tank, the crystal nucleus response device, 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 according to claim 3, wherein the method is characterized in that, In step (2), use the first agitator to stir the industrial ammonium sulfate slurry in the slurry pre-distribution tank, with a stirring rate ranging from 40 to 400 r / min.

8. The method according to claim 3, wherein the method is characterized in that, In step (2), use the second agitator to stir under constant temperature conditions at a temperature of 35-95℃, with a stirring rate ranging from 40 to 300 r / min.

9. The method according to claim 3, wherein the method is characterized in that, In step (2), use the first agitator to stir the industrial ammonium sulfate slurry in the slurry pre-distribution tank, with a stirring rate ranging from 40 to 400 r / min.

10. The method of claim 3, wherein the method is used for monitoring the metastable zone width of a crystallization system with high impurity content and low light transmittance. 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-distribution tank are detected by the first infrared 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 fiber monitoring probe and the second infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the upper first layer tray of the crystal nucleus response device are detected by the third infrared fiber monitoring probe and the third infrared temperature monitoring probe; the conductivity and temperature of the circulating water and the solution in the upper second layer tray of the crystal nucleus response device are detected by the fourth infrared 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 of the lower part of the crystal nucleus response device are detected by the fifth infrared 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.

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