Improved urea sampling device

Abstract

The invention provides an improved urea sampling device, which relates to the technical field of urea sampling devices, and comprises an intelligent sampling module, a multistage temperature control transmission module, an online processing analysis module, a self-cleaning control module and an energy efficiency optimization module. Anti-crystallization total cross-section sampling is achieved by arranging the intelligent sampling module, the problems that an existing device is limited in sampling point coverage range and insufficient in sample representativeness are solved, the overall working condition in a urea production main pipeline can be truly reflected, and meanwhile the multi-stage temperature control transmission module, the self-cleaning control module and the like are combined; according to the device, crystallization blockage caused by improper temperature control in the sampling process is avoided, the sampling continuity is guaranteed through cooperative work of all the modules, the sampling accuracy and energy efficiency are improved, and the defects of an existing device in the aspects of accuracy, continuity and energy efficiency are effectively overcome.

Description

Technical Field

[0001] This invention belongs to the technical field of urea sampling devices, specifically relating to an improved urea sampling device. Background Technology

[0002] In the urea production process, real-time sampling and analysis of molten urea is a key step in ensuring product quality and optimizing the production process. However, existing urea sampling devices face many technical challenges in practical applications, which seriously affect the accuracy, continuity and energy efficiency of sampling. In the sampling process, existing equipment often has limited sampling point coverage, making it difficult to achieve full-section sampling. This results in insufficient representativeness of the obtained samples, which cannot truly reflect the overall operating conditions within the urea production pipeline. At the same time, urea melt is prone to crystallization during sampling due to improper temperature control, falling below its critical crystallization temperature and causing blockage of the sampling pipeline. Furthermore, there is a lack of an effective backup path switching mechanism. Once a blockage occurs, the machine must be shut down for treatment, which seriously affects the continuity of sampling. Summary of the Invention

[0003] The present invention provides an improved urea sampling device to solve at least one of the technical problems mentioned above.

[0004] To address the aforementioned technical problems, this invention discloses an improved urea sampling device, comprising: The intelligent sampling module is used to perform anti-crystallization full-section sampling based on the real-time operating conditions of the urea production pipeline to obtain urea molten liquid; A multi-stage temperature control transmission module is used to perform multi-stage temperature control on the urea molten liquid output by the intelligent sampling module to maintain supersaturated stable flow and obtain a supersaturated solution. The online processing and analysis module is used to eliminate bubbles, dynamically detect concentrations, and cool samples of supersaturated solutions delivered by the multi-stage temperature-controlled transmission module. The self-cleaning control module is used to trigger anti-crystallization operation based on the concentration data from the online processing and analysis module and the viscosity data from the multi-level temperature control transmission module. The energy efficiency optimization module is used to dynamically adjust the heating power and cooling energy consumption based on the operating status of the sampling device.

[0005] Preferably, the intelligent sampling module includes: The full-section sampling unit is used to extract molten urea liquid from the main urea production line through a double-helix sampling tube with 20° inclined guide fins on the inner wall. The path switching unit is used to switch to a backup sampling tube when crystallization blockage occurs in the urea sampling pipeline. The temperature maintenance unit is used to control the output sample temperature within the range of 132-135℃ via a PTC heater.

[0006] Preferably, the multi-level temperature control transmission module includes: Dual-mode heat tracing unit, used to activate electric heat tracing tape or steam heat tracing based on the status of the transmission pipeline; The dynamic temperature control unit is used to adjust the heating power based on real-time viscosity data collected by the online viscosity monitor; Temperature stabilization unit is used to maintain temperature fluctuations of ≤±0.5℃ during the transmission process through a vacuum insulation layer.

[0007] Preferably, the dynamic temperature control unit includes: The viscosity monitoring subunit is used to collect the viscosity value of supersaturated solutions in real time. ; The power regulation subunit is used to adjust the heat tracing power based on a viscosity threshold. When 120cP≤ Increase the heat tracing power by 10% when the output is less than 150 cP. when Increase the heat tracing power by 20% when the output is ≥150cP.

[0008] Preferably, the online processing and analysis module includes: A bubble elimination unit is used to break up dissolved gases based on a received supersaturated solution using 40kHz ultrasound. The optical detection unit is used to project a 650nm laser beam onto the bubble-free solution after the bubble elimination unit, measure the refraction angle offset through a refractive sensor, and calculate the real-time urea concentration value based on the refraction angle-concentration mapping relationship. The rapid cooling unit is used to cool the solution processed by the optical detection unit to below 25°C within 3 seconds via a microchannel heat exchanger.

[0009] Preferably, the optical detection unit includes: A laser emitting unit is used to project a 650nm collimated laser beam into the solution in a constant-temperature analysis cell; The refraction angle acquisition unit is used to obtain the refraction angle shift of the laser beam after passing through the solution. ; Concentration calculation unit, used based on the formula C=K×( - Calculate the urea concentration, where K is the concentration conversion factor. The reference angle is the pure water, and C is the mass percentage concentration of the urea solution.

[0010] Preferably, the self-cleaning control module includes: Crystallization prediction unit, used based on concentration data C and viscosity data Perform crystallization risk classification: If C≥40% and A pulse of ≥120 cP lasting for 5 minutes is classified as a Level 1 risk. If C≥45% and A pulse of ≥150 cP lasting for 3 minutes is classified as a level 2 risk. The pulse backflush unit is used to release pulses into the sampling and transmission pipelines based on the secondary risk assessment results. Specifically: In the event of a Level 1 risk, a 0.4 MPa nitrogen pulse is released into the sampling and transmission pipeline for 5 seconds. At level 2 risk, a 0.6 MPa steam pulse is released into the sampling and transmission pipeline for 3 seconds.

[0011] Preferably, the energy efficiency optimization module includes: The load prediction unit is used to predict the sampled flow rate for the next 30 minutes based on the urea production load curve. The dynamic power adjustment unit is used to proportionally adjust the heat tracing power based on the predicted flow rate. When the predicted flow rate is less than 60% of the design value, the heating power should be reduced to 70%. When the predicted flow rate is ≥ 90% of the design value, the heating power is increased to 110%. The waste heat recovery unit is used to recover waste heat from steam tracing via a plate heat exchanger, which is then supplied to the rapid cooling unit of the online processing and analysis module. Specifically: Waste heat from steam condensate at a temperature ≥100℃ is recovered and transported to the coolant inlet of the microchannel heat exchanger through a heat medium circulation system, reducing the energy consumption of the cooling unit by 40%-60%.

[0012] Preferably, it further includes a temperature buffer module, which is connected between the rapid cooling unit and the closed-loop recovery module, and includes: The stepped cooling chamber includes three temperature control zones: 80±2℃ zone, 50±2℃ zone, and 30±1℃ zone. Residence time controller, according to formula ;in, Total stay time The real-time concentration of urea solution detected by the online processing and analysis module; The crystallization inhibitor injection unit injects 0.1‰ polyacrylamide solution when a temperature drop rate > 15℃ / second is detected.

[0013] Preferably, it also includes a closed-loop recovery module, which is connected to the output of the temperature buffer module and is used to perform graded recovery or harmless treatment of the cooled sample. The closed-loop recovery module includes: The recovery pump unit is used to pump the sample output from the temperature buffer module into the recovery pipeline at a flow rate of 0.5-2L / min. The recovery pump adopts frequency conversion control, and its speed is linked to the sampling frequency of the online processing and analysis module. The precision filtration unit has a built-in PTFE filter element with a 1μm pore size, which is used to intercept tiny crystalline particles that may be present in the sample. The filter element is automatically triggered to replace when the pressure difference between the inlet and outlet exceeds 0.15MPa. The anti-crystallization conveying unit maintains the temperature of the recovery pipeline at 80-90℃ through a heat tracing jacket and is equipped with a spiral flow guiding structure to reduce flow dead angles. The temperature control accuracy of the heat tracing jacket is ±1℃. The pressure regulating unit is used to stabilize the output pressure of the recovery pipeline at 0.3-0.5MPa. When the pressure fluctuation of the urea production main pipeline exceeds ±0.1MPa, it automatically cuts off the recovery path and starts the bypass circulation.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves anti-crystallization full-section sampling through an intelligent sampling module, ensuring the representativeness and authenticity of the samples. The multi-stage temperature control transmission module maintains supersaturated stable flow to avoid crystallization problems during transmission. The online processing and analysis module enables efficient processing and analysis of samples. The self-cleaning control module can trigger anti-crystallization operation in time to reduce the risk of pipeline blockage. The energy efficiency optimization module dynamically adjusts energy consumption to improve the energy efficiency of the device. The collaborative work of each module improves the accuracy, stability and energy efficiency of urea sampling. This invention achieves full-section sampling without crystallization by setting up an intelligent sampling module, which solves the problems of limited sampling point coverage and insufficient sample representativeness in existing devices. It can truly reflect the overall operating conditions within the urea production pipeline. At the same time, combined with multi-level temperature control transmission modules and self-cleaning control modules, it avoids crystallization blockage caused by improper temperature control during the sampling process. Moreover, the coordinated work of each module ensures the continuity of sampling, improves the accuracy and energy efficiency of sampling, and effectively addresses the shortcomings of existing devices in terms of accuracy, continuity and energy efficiency. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall improved urea sampling device of the present invention. Detailed Implementation

[0016] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0017] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0018] The present invention provides the following embodiments. Example 1 This invention provides an improved urea sampling device, such as... Figure 1 As shown, it includes: The intelligent sampling module is used to perform anti-crystallization full-section sampling based on the real-time operating conditions of the urea production pipeline to obtain urea molten liquid; A multi-stage temperature control transmission module is used to perform multi-stage temperature control on the urea molten liquid output by the intelligent sampling module to maintain supersaturated stable flow and obtain a supersaturated solution. The online processing and analysis module is used to eliminate bubbles, dynamically detect concentrations, and cool samples in the supersaturated solution delivered by the multi-stage temperature-controlled transmission module. The self-cleaning control module is used to trigger anti-crystallization operation based on the concentration data from the online processing and analysis module and the viscosity data from the multi-level temperature control transmission module. The energy efficiency optimization module is used to dynamically adjust the heating power and cooling energy consumption based on the operating status of the sampling device.

[0019] In this embodiment, anti-crystallization full-section sampling means that the sampling point covers the entire cross-section of the pipeline and the sampling temperature is maintained at 132-135℃, which is higher than the critical crystallization temperature of urea.

[0020] The working principle and beneficial effects of the above technical solution are as follows: the intelligent sampling module performs anti-crystallization full-section sampling based on the real-time operating conditions of the urea production pipeline to obtain urea molten liquid; the multi-stage temperature control transmission module performs multi-stage temperature control on the urea molten liquid output by the intelligent sampling module to maintain supersaturated stable flow and obtain a supersaturated solution; the online processing and analysis module performs bubble elimination, dynamic concentration detection and sample cooling on the supersaturated solution transported by the multi-stage temperature control transmission module; the self-cleaning control module triggers anti-crystallization operation based on the concentration data of the online processing and analysis module and the viscosity data of the multi-stage temperature control transmission module; and the energy efficiency optimization module dynamically adjusts the heating power and cooling energy consumption based on the operating status of the sampling device. The intelligent sampling module enables full-section sampling to prevent crystallization, ensuring the representativeness and authenticity of the samples. The multi-stage temperature control transmission module maintains supersaturated stable flow to avoid crystallization during transmission. The online processing and analysis module enables efficient processing and analysis of samples. The self-cleaning control module can trigger anti-crystallization operation in time to reduce the risk of pipeline blockage. The energy efficiency optimization module dynamically adjusts energy consumption to improve the energy efficiency of the device. The collaborative work of each module improves the accuracy, stability and energy efficiency of urea sampling. This invention achieves full-section sampling without crystallization by setting up an intelligent sampling module, which solves the problems of limited sampling point coverage and insufficient sample representativeness in existing devices. It can truly reflect the overall operating conditions within the urea production pipeline. At the same time, combined with multi-level temperature control transmission modules and self-cleaning control modules, it avoids crystallization blockage caused by improper temperature control during the sampling process. Moreover, the coordinated work of each module ensures the continuity of sampling, improves the accuracy and energy efficiency of sampling, and effectively addresses the shortcomings of existing devices in terms of accuracy, continuity and energy efficiency.

[0021] Example 2 Based on Example 1, the intelligent sampling module includes: The full-section sampling unit is used to extract molten urea liquid from the main urea production line through a double-helix sampling tube with 20° inclined guide fins on the inner wall. The path switching unit is used to switch to a backup sampling tube when crystallization blockage occurs in the urea sampling pipeline. The temperature maintenance unit is used to control the output sample temperature within the range of 132-135℃ via a PTC heater.

[0022] The working principle and beneficial effects of the above technical solution are as follows: the full-section sampling unit in the intelligent sampling module realizes the swirling extraction of urea melt on the main urea production line through the double helix sampling tube with 20° inclined guide fins on the inner wall; the path switching unit switches the backup sampling tube when crystallization blockage occurs in the urea sampling pipeline; and the temperature maintenance unit controls the output sample temperature within the range of 132-135℃ through the PTC heater. The full-section sampling unit's double-helix sampling tube, combined with 20° inclined guide fins, achieves swirling extraction, covering the entire cross-section of the pipe and ensuring comprehensive and representative sampling. The path switching unit promptly switches to a backup tube when the pipeline is blocked, ensuring the continuity of the sampling process. The temperature maintenance unit controls the sample temperature at 132-135℃, which is higher than the critical crystallization temperature of urea, effectively preventing crystallization of the sample during the sampling stage and improving the reliability of sampling.

[0023] Example 3 Based on Example 1, the multi-level temperature control transmission module includes: Dual-mode heat tracing unit, used to activate electric heat tracing tape or steam heat tracing based on the status of the transmission pipeline; The dynamic temperature control unit is used to adjust the heating power based on real-time viscosity data collected by the online viscosity monitor; A temperature stabilization unit is used to maintain temperature fluctuations of ≤±0.5℃ during the transmission process through a vacuum insulation layer; The dynamic temperature control unit includes: The viscosity monitoring subunit is used to collect the viscosity value of supersaturated solutions in real time. ; The power regulation subunit is used to adjust the heat tracing power based on a viscosity threshold. When 120cP≤ Increase the heat tracing power by 10% when the output is less than 150 cP. when Increase the heat tracing power by 20% when the output is ≥150cP.

[0024] The working principle and beneficial effects of the above technical solution are as follows: the dual-mode heat tracing unit in the multi-stage temperature control transmission module starts the electric heat tracing tape or steam heat tracing based on the state of the transmission pipeline, and the dynamic temperature adjustment unit collects the viscosity value of the supersaturated solution in real time through the viscosity monitoring subunit. The power regulation subunit adjusts the heating power based on a viscosity threshold. When 120cP ≤ Increase the heat tracing power by 10% when the output is less than 150 cP. When the power is ≥150cP, the heat tracing power is increased by 20%, and the temperature stabilization unit maintains the temperature fluctuation during the transmission process ≤±0.5℃ through the vacuum insulation layer; The dual-mode heat tracing unit can flexibly select between electric heat tracing tape and steam heat tracing according to the condition of the transmission pipeline, adapting to different working conditions. The dynamic temperature control unit is based on viscosity value. Precisely adjust the heating power according to the change, when 120cP ≤ Increase power by 10% when <150cP, when At ≥150cP, the power is increased by 20% to ensure that the viscosity of the supersaturated solution remains stable within a suitable range and to maintain stable flow. The temperature stabilization unit controls temperature fluctuations to ≤±0.5℃ through a vacuum insulation layer, reducing the impact of temperature changes on the solution state, further preventing crystallization, and improving the stability of the transmission process.

[0025] Example 4 Based on Example 1, the online processing and analysis module includes: A bubble elimination unit is used to break up dissolved gases based on a received supersaturated solution using 40kHz ultrasound. The optical detection unit is used to project a 650nm laser beam onto the bubble-free solution after the bubble elimination unit, measure the refraction angle offset through a refractive sensor, and calculate the real-time urea concentration value based on the refraction angle-concentration mapping relationship. A rapid cooling unit is used to cool the solution processed by the optical detection unit to below 25°C within 3 seconds via a microchannel heat exchanger. The optical detection unit includes: A laser emitting unit is used to project a 650nm collimated laser beam into the solution in a constant-temperature analysis cell; The refraction angle acquisition unit is used to obtain the refraction angle shift of the laser beam after passing through the solution. ; Concentration calculation unit, used based on the formula C=K×( - Calculate the urea concentration, where K is the concentration conversion factor. The reference angle is the pure water, and C is the mass percentage concentration of the urea solution.

[0026] The working principle and beneficial effects of the above technical solution are as follows: In the online processing and analysis module, the bubble elimination unit uses 40kHz ultrasound to break up dissolved gases in the received supersaturated solution; the laser emission unit of the optical detection unit projects a 650nm collimated laser beam into the solution in the constant temperature analysis cell; and the refraction angle acquisition unit obtains the refraction angle shift of the laser beam after passing through the solution. The concentration calculation unit is based on the formula C=K×( - The urea concentration is calculated, and the rapid cooling unit cools the solution processed by the optical detection unit to below 25°C within 3 seconds through a microchannel heat exchanger. The bubble elimination unit uses 40kHz ultrasound to break up dissolved gases, avoiding interference from bubbles in subsequent detection and ensuring detection accuracy. The optical detection unit uses a 650nm laser beam combined with a refractive sensor, using the formula C=K×( - The concentration was calculated, and the mapping relationship between the refraction angle offset and the concentration was used to achieve accurate dynamic detection of the concentration. The rapid cooling unit cooled the solution to below 25°C within 3 seconds through a microchannel heat exchanger, which improved the sample cooling efficiency, laid the foundation for subsequent processing, and improved the efficiency and accuracy of online processing and analysis as a whole.

[0027] Example 5 Based on Example 1, the self-cleaning control module includes: Crystallization prediction unit, used based on concentration data C and viscosity data Perform crystallization risk classification: If C≥40% and A pulse of ≥120 cP lasting for 5 minutes is classified as a Level 1 risk. If C≥45% and A pulse of ≥150 cP lasting for 3 minutes is classified as a level 2 risk. The pulse backflush unit is used to release pulses into the sampling and transmission pipelines based on the secondary risk assessment results. Specifically: In the event of a Level 1 risk, a 0.4 MPa nitrogen pulse is released into the sampling and transmission pipeline for 5 seconds. At level 2 risk, a 0.6 MPa steam pulse is released into the sampling and transmission pipeline for 3 seconds.

[0028] The working principle and beneficial effects of the above technical solution are as follows: the crystallization prediction unit in the self-cleaning control module is based on concentration data C and viscosity data. The crystallization risk classification is performed. If C≥40% and η≥120cP lasts for 5 minutes, it is judged as a level 1 risk. If C≥45% and η≥150cP lasts for 3 minutes, it is judged as a level 2 risk. The pulse backflush unit releases a pulse to the sampling and transmission pipeline based on the risk judgment result. In the case of level 1 risk, a 0.4MPa nitrogen pulse is released to the sampling and transmission pipeline for 5 seconds. In the case of level 2 risk, a 0.6MPa steam pulse is released for 3 seconds. The crystallization prediction unit classifies risks by setting specific concentration and viscosity thresholds and durations. Level 1 risk corresponds to C ≥ 40% and ≥120 cP lasting for 5 minutes, Level 2 risk corresponds to C≥45% and With a pulse pressure of ≥150 cP for 3 minutes, the system can accurately identify the crystallization risk level. The pulse backflush unit releases pulses with corresponding parameters according to different risk levels. For level one risk, a 0.4 MPa nitrogen pulse is used for 5 seconds, and for level two risk, a 0.6 MPa steam pulse is used for 3 seconds. This can effectively remove crystals in the pipeline, prevent blockage, ensure the continuous and stable operation of the device, and reduce maintenance costs.

[0029] Example 6 Based on Example 1, the energy efficiency optimization module includes: The load prediction unit is used to predict the sampled flow rate for the next 30 minutes based on the urea production load curve. The dynamic power adjustment unit is used to proportionally adjust the heat tracing power based on the predicted flow rate. When the predicted flow rate is less than 60% of the design value, the heating power should be reduced to 70%. When the predicted flow rate is ≥ 90% of the design value, the heating power is increased to 110%. The waste heat recovery unit is used to recover waste heat from steam tracing via a plate heat exchanger, which is then supplied to the rapid cooling unit of the online processing and analysis module. Specifically: Waste heat from steam condensate at a temperature ≥100℃ is recovered and transported to the coolant inlet of the microchannel heat exchanger through a heat medium circulation system, reducing the energy consumption of the cooling unit by 40%-60%.

[0030] The working principle and beneficial effects of the above technical solution are as follows: The load prediction unit in the energy efficiency optimization module predicts the sampling flow rate for the next 30 minutes based on the urea production load curve. The dynamic power adjustment unit adjusts the heat tracing power proportionally according to the predicted flow rate. When the predicted flow rate is less than 60% of the design value, the heat tracing power is reduced to 70%. When the predicted flow rate is greater than or equal to 90% of the design value, the heat tracing power is increased to 110%. The waste heat recovery unit recovers the waste heat of steam condensate with a temperature ≥100℃ through a plate heat exchanger and transports it to the coolant inlet of the microchannel heat exchanger through a heat medium circulation system, thereby reducing the energy consumption of the cooling unit by 40%-60%. The load prediction unit predicts the sampled flow rate based on the production load curve, and the dynamic power adjustment unit adjusts the heat tracing power accordingly. When the flow rate is 60% lower than the design value, the power is reduced to 70%, and when it is 90% or higher, it is increased to 110%, so that the heat tracing power matches the actual demand and avoids energy waste. The waste heat recovery unit recovers the waste heat of steam condensate at ≥100℃ and uses it for the cooling unit, reducing cooling energy consumption by 40%-60%. Overall, the optimization of heat tracing and cooling energy consumption is achieved, the energy efficiency ratio of the device is improved, and operating costs are saved.

[0031] Example 7 Based on Embodiment 1, a temperature buffer module is also included. The temperature buffer module is connected between the rapid cooling unit and the closed-loop recovery module, and includes: The stepped cooling chamber includes three temperature control zones: 80±2℃ zone, 50±2℃ zone, and 30±1℃ zone. Residence time controller, according to formula ;in, Total stay time The real-time concentration of urea solution detected by the online processing and analysis module; The crystallization inhibitor injection unit injects 0.1‰ polyacrylamide solution when a temperature drop rate > 15℃ / second is detected.

[0032] The working principle and beneficial effects of the above technical solution are as follows: The temperature buffer module is connected between the rapid cooling unit and the closed-loop recovery module. The stepped cooling chamber includes three temperature control zones: 80±2℃, 50±2℃, and 30±1℃. The residence time controller controls the total residence time according to the formula t=0.5+0.1(C-30) (where t is the total residence time and C is the real-time concentration of urea solution detected by the online processing and analysis module). The crystallization inhibitor injection unit injects 0.1‰ polyacrylamide solution when the temperature drop rate is detected to be >15℃ / second. The three-stage temperature control zone of the stepped cooling chamber enables gradual cooling of the sample, avoiding crystallization caused by rapid cooling. The residence time controller adjusts the total residence time according to the real-time concentration C using the formula t=0.5+0.1(C-30). The higher the concentration, the longer the residence time, ensuring that the cooling process is sufficient and uniform. The crystallization inhibitor injection unit injects 0.1‰ polyacrylamide solution when the cooling rate is too fast, effectively inhibiting crystal formation, protecting the subsequent closed-loop recovery module, and improving the stability and reliability of the system.

[0033] Example 8 Based on Example 1, a closed-loop recovery module is also included. This closed-loop recovery module is connected to the output of the temperature buffer module and is used for graded recovery or harmless treatment of the cooled sample. The closed-loop recovery module includes: The recovery pump unit is used to pump the sample output from the temperature buffer module into the recovery pipeline at a flow rate of 0.5-2L / min. The recovery pump adopts frequency conversion control, and its speed is linked to the sampling frequency of the online processing and analysis module. The precision filtration unit has a built-in PTFE filter element with a 1μm pore size, which is used to intercept tiny crystalline particles that may be present in the sample. The filter element is automatically triggered to replace when the pressure difference between the inlet and outlet exceeds 0.15MPa. The anti-crystallization conveying unit maintains the temperature of the recovery pipeline at 80-90℃ through a heat tracing jacket and is equipped with a spiral flow guiding structure to reduce flow dead angles. The temperature control accuracy of the heat tracing jacket is ±1℃. The pressure regulating unit is used to stabilize the output pressure of the recovery pipeline at 0.3-0.5MPa. When the pressure fluctuation of the urea production main pipeline exceeds ±0.1MPa, it automatically cuts off the recovery path and starts the bypass circulation.

[0034] The working principle and beneficial effects of the above technical solution are as follows: The closed-loop recovery module is connected to the output end of the temperature buffer module. The recovery pump unit pumps the sample output from the temperature buffer module into the recovery pipeline at a flow rate of 0.5-2L / min. The recovery pump adopts frequency conversion control and the speed is linked with the sampling frequency of the online processing and analysis module. The precision filtration unit has a built-in 1μm pore size polytetrafluoroethylene filter element to intercept any small crystalline particles that may exist in the sample. When the pressure difference between the inlet and outlet of the filter element exceeds 0.15MPa, a replacement prompt is automatically triggered. The anti-crystallization conveying unit maintains the temperature of the recovery pipeline at 80-90℃ through a heat tracing jacket and sets a spiral guide structure to reduce flow dead angles. The temperature control accuracy of the heat tracing jacket is ±1℃. The pressure regulating unit stabilizes the output pressure of the recovery pipeline at 0.3-0.5MPa. When the pressure fluctuation of the urea production main pipeline exceeds ±0.1MPa, the recovery path is automatically cut off and the bypass circulation is started. The frequency conversion control of the recovery pump unit is linked to the sampling frequency, ensuring that the recovery flow rate matches the sampling volume and avoiding over- or under-recovery. The 1μm PTFE filter element of the precision filtration unit effectively traps tiny crystalline particles, protecting the recovery pipeline. When the pressure difference exceeds 0.15MPa, it automatically prompts for filter element replacement, facilitating timely maintenance. The heat tracing jacket of the anti-crystallization conveying unit maintains the temperature at 80-90℃ with a temperature control accuracy of ±1℃. Combined with the spiral guide structure, it reduces dead angles and prevents crystal formation. The pressure regulating unit stably outputs pressure at 0.3-0.5MPa. When the pressure fluctuation is too large, it activates the bypass circulation to ensure recovery safety. This achieves efficient graded recovery or harmless treatment of samples, improving resource utilization and reducing waste and pollution.

[0035] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An improved urea sampling device, characterized in that: include: The intelligent sampling module is used to perform anti-crystallization full-section sampling based on the real-time operating conditions of the urea production pipeline to obtain urea molten liquid; A multi-stage temperature control transmission module is used to perform multi-stage temperature control on the urea molten liquid output by the intelligent sampling module to maintain supersaturated stable flow and obtain a supersaturated solution. The online processing and analysis module is used to eliminate bubbles, dynamically detect concentrations, and cool samples in the supersaturated solution delivered by the multi-stage temperature-controlled transmission module. The self-cleaning control module is used to trigger anti-crystallization operation based on the concentration data from the online processing and analysis module and the viscosity data from the multi-level temperature control transmission module. The energy efficiency optimization module is used to dynamically adjust the heating power and cooling energy consumption based on the operating status of the sampling device.

2. The improved urea sampling device according to claim 1, characterized in that: The intelligent sampling module includes: The full-section sampling unit is used to extract molten urea liquid from the main urea production line through a double-helix sampling tube with 20° inclined guide fins on the inner wall. The path switching unit is used to switch to a backup sampling tube when crystallization blockage occurs in the urea sampling pipeline. The temperature maintenance unit is used to control the output sample temperature within the range of 132-135℃ via a PTC heater.

3. The improved urea sampling device according to claim 1, characterized in that: The multi-level temperature control transmission module includes: Dual-mode heat tracing unit, used to activate electric heat tracing tape or steam heat tracing based on the status of the transmission pipeline; The dynamic temperature control unit is used to adjust the heating power based on real-time viscosity data collected by the online viscosity monitor; Temperature stabilization unit is used to maintain temperature fluctuations of ≤±0.5℃ during the transmission process through a vacuum insulation layer.

4. An improved urea sampling device according to claim 3, characterized in that: The dynamic temperature control unit includes: The viscosity monitoring subunit is used to collect the viscosity value of supersaturated solutions in real time. ; The power regulation subunit is used to adjust the heat tracing power based on a viscosity threshold. When 120cP≤ Increase the heat tracing power by 10% when the output is less than 150 cP. when Increase the heat tracing power by 20% when the output is ≥150cP.

5. An improved urea sampling device according to claim 1, characterized in that: The online processing and analysis module includes: A bubble elimination unit is used to break up dissolved gases based on a received supersaturated solution using 40kHz ultrasound. The optical detection unit is used to project a 650nm laser beam onto the bubble-free solution after the bubble elimination unit, measure the refraction angle offset through a refractive sensor, and calculate the real-time urea concentration value based on the refraction angle-concentration mapping relationship. The rapid cooling unit is used to cool the solution processed by the optical detection unit to below 25°C within 3 seconds via a microchannel heat exchanger.

6. An improved urea sampling device according to claim 5, characterized in that: The optical detection unit includes: A laser emitting unit is used to project a 650nm collimated laser beam into the solution in a constant-temperature analysis cell; The refraction angle acquisition unit is used to obtain the refraction angle shift of the laser beam after passing through the solution. ; Concentration calculation unit, used based on the formula C=K×( - Calculate the urea concentration, where K is the concentration conversion factor. The reference angle is the pure water, and C is the mass percentage concentration of the urea solution.

7. An improved urea sampling device according to claim 1, characterized in that: The self-cleaning control module includes: Crystallization prediction unit, used based on concentration data C and viscosity data Perform crystallization risk classification: If C≥40% and A pulse of ≥120 cP lasting for 5 minutes is classified as a Level 1 risk. If C≥45% and A pulse of ≥150 cP lasting for 3 minutes is classified as a level 2 risk. The pulse backflush unit is used to release pulses into the sampling and transmission pipelines based on the secondary risk assessment results. Specifically: In the event of a Level 1 risk, a 0.4 MPa nitrogen pulse is released into the sampling and transmission pipeline for 5 seconds. At level 2 risk, a 0.6 MPa steam pulse is released into the sampling and transmission pipeline for 3 seconds.

8. An improved urea sampling device according to claim 1, characterized in that: The energy efficiency optimization module includes: The load prediction unit is used to predict the sampled flow rate for the next 30 minutes based on the urea production load curve. The dynamic power adjustment unit is used to proportionally adjust the heat tracing power based on the predicted flow rate. When the predicted flow rate is less than 60% of the design value, the heating power should be reduced to 70%. When the predicted flow rate is ≥ 90% of the design value, the heating power is increased to 110%. The waste heat recovery unit is used to recover waste heat from steam tracing via a plate heat exchanger, which is then supplied to the rapid cooling unit of the online processing and analysis module. Specifically: Waste heat from steam condensate at a temperature ≥100℃ is recovered and transported to the coolant inlet of the microchannel heat exchanger through a heat medium circulation system, reducing the energy consumption of the cooling unit by 40%-60%.

9. An improved urea sampling device according to claim 1, characterized in that: It also includes a temperature buffer module, which is connected between the rapid cooling unit and the closed-loop recovery module, and includes: The stepped cooling chamber includes three temperature control zones: 80±2℃ zone, 50±2℃ zone, and 30±1℃ zone. Residence time controller, according to formula ;in, Total stay time The real-time concentration of urea solution detected by the online processing and analysis module; The crystallization inhibitor injection unit injects 0.1‰ polyacrylamide solution when a temperature drop rate > 15℃ / second is detected.

10. An improved urea sampling device according to claim 1, characterized in that: It also includes a closed-loop recovery module, which is connected to the output of the temperature buffer module and is used to perform graded recovery or harmless treatment of the cooled sample. The closed-loop recovery module includes: The recovery pump unit is used to pump the sample output from the temperature buffer module into the recovery pipeline at a flow rate of 0.5-2L / min. The recovery pump adopts frequency conversion control, and its speed is linked to the sampling frequency of the online processing and analysis module. The precision filtration unit has a built-in PTFE filter element with a 1μm pore size, which is used to intercept tiny crystalline particles that may be present in the sample. The filter element is automatically triggered to replace when the pressure difference between the inlet and outlet exceeds 0.15MPa. The anti-crystallization conveying unit maintains the temperature of the recovery pipeline at 80-90℃ through a heat tracing jacket and is equipped with a spiral flow guiding structure to reduce flow dead angles. The temperature control accuracy of the heat tracing jacket is ±1℃. The pressure regulating unit is used to stabilize the output pressure of the recovery pipeline at 0.3-0.5MPa. When the pressure fluctuation of the urea production main pipeline exceeds ±0.1MPa, it automatically cuts off the recovery path and starts the bypass circulation.

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