A method for preventing blockage in heating tubes for nitrate co-production

Abstract

This invention discloses an anti-clogging method for a heating tube system in nitrate co-production, relating to the field of nitrate co-production technology. Its key technical points include the following steps: Step 1, Speed-up Circulation: A circulation pump is added to the pipeline of the second evaporation system, increasing the fluid flow rate in the evaporator tank of the second evaporation system 2 to 4 times per day to 130% to 160% of the original flow rate; Step 2, Evaporation Circulation: The cubic liquid in the evaporator tank of the second evaporation system is circulated and evaporated. Every 6 to 10 hours, the concentration of the cubic liquid in the evaporator tank of the second evaporation system is reduced, lowering the normal liquid level in the evaporator tank from 40% to 20%, and then water is added to 60%. This invention can improve production efficiency, reduce economic losses, and ensure production safety.

Description

Technical Field

[0001] This invention relates to the field of nitrate co-production technology, and in particular to a method for preventing blockage in heating tubes used in nitrate co-production. Background Technology

[0002] In the co-production of nitrates, the heating tubes, as the core heat exchange equipment, play a crucial role. Their main function is to heat the solution, accelerating the evaporation of water and thus significantly improving the efficiency of nitrate production. However, unfortunately, due to the inevitable presence of impurities in the solution, such as calcium and magnesium ions and crystals, these substances gradually deposit inside the heating tubes, forming blockages that are difficult to remove.

[0003] This phenomenon not only severely hinders the smooth flow of the solution and reduces salt production efficiency, but also, over time, the accumulation of deposits can cause excessive pressure on the equipment, leading to damage. More seriously, once the heating tubes become severely blocked, production often needs to be shut down for cleaning and repair, which not only further reduces production efficiency but also brings huge economic losses and safety risks.

[0004] Given the severity and prevalence of tube blockage in heating tubes, developing an efficient and reliable anti-blockage technology is of paramount importance. This would not only solve current production bottlenecks and improve production efficiency, but also reduce equipment maintenance and replacement costs, extend equipment lifespan, and possess significant practical application value and broad market prospects.

[0005] Currently, our company's nitrate co-production process mainly employs advanced multi-effect vacuum evaporation, mother liquor recovery, and secondary steam pressurization. In the entire process, the nitrate solution first enters the multi-effect vacuum evaporation system, where sodium sulfate and sodium chloride precipitate at different temperatures. Subsequently, these precipitated solids are pumped into a centrifugal dehydration and drying system for further processing, ultimately yielding dried products which are then sent to the storage workshop for packaging and storage. The mother liquor is returned to the evaporation system, achieving resource recycling.

[0006] However, in actual production, we found that the second evaporation system (i.e., system 202) frequently experienced problems such as increased temperature difference, heating chamber pipe blockage, and decreased heat transfer coefficient. These problems not only shortened the production cycle but also frequently led to production shutdowns. Statistics show that from January to June 2023, there were as many as four shutdowns for cleaning and flushing the boiling tanks due to heating chamber pipe blockage. This not only severely impacted output and production time but also directly resulted in economic losses of up to 4 million yuan.

[0007] Therefore, in order to solve this technical problem, we urgently need to develop an effective heating tube anti-clogging technology to improve production efficiency, reduce economic losses and ensure production safety. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention aims to develop an anti-clogging method for heating tubes used in nitrate co-production, thereby improving production efficiency, reducing economic losses, and ensuring production safety.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A method for preventing blockage in a heating tube for nitrate co-production includes the following steps:

[0011] Step 1, Speed-up Circulation: Add a circulation pump to the pipeline of the second evaporation system, and increase the flow rate of the fluid in the evaporation tank of the second evaporation system by the circulation pump 2 to 4 times a day, increasing it to 130% to 160% of the original flow rate;

[0012] Step 2, Evaporation Circulation: The cubic liquid in the evaporator of the second evaporation system is circulated and evaporated. Every 6 to 10 hours, the concentration of the cubic liquid in the evaporator of the second evaporation system is reduced, and the normal liquid level in the evaporator of the second evaporation system is reduced from 40% to 20%, and then water is added to 60%.

[0013] Preferably, the method further includes a third step, which is to reduce the calcium and magnesium content: the calcium and magnesium content in the brine is reduced by using quicklime and flue gas, so that the calcium and magnesium content is reduced to 3 ppm / l to 5 ppm / l, and the calcium and magnesium content in the evaporator of the second evaporation system does not exceed 50 ppm.

[0014] Preferably, the device for measuring calcium and magnesium concentration in step three is a calcium and magnesium ion sensor.

[0015] Preferably, in the speed-up cycle of step one, the steam inlet flow rate of the second evaporation system is reduced to no more than 0.2 MPa.

[0016] Preferably, in step one, the rate-increasing cycle is repeated 3 times per day, and the flow rate is adjusted to 150% of the original flow rate.

[0017] Preferably, the evaporation cycle interval in step two is 8 hours, which reduces the Baumé degree from 27 to 25.

[0018] Preferably, the method further includes step four, real-time monitoring: setting up a sensor group, which includes a temperature sensor, a pressure sensor, and a flow rate sensor, and the temperature sensor, pressure sensor, and flow rate sensor respectively monitor the temperature, pressure, and flow rate parameters within the second evaporation system.

[0019] The present invention has the following beneficial effects:

[0020] I. Reduce heating tube blockage and improve production efficiency; Increased circulation speed: By adding a circulation pump to the pipeline of the second evaporation system and increasing the fluid flow rate to 130% to 160% (preferably 150%) of the original flow rate 2 to 4 times a day (preferably 3 times), it is possible to effectively avoid the formation of sediments due to low flow rate. The higher flow rate can flush away impurities attached to the pipe wall, thereby significantly reducing the blockage of the heating tubes; Evaporation circulation: Every 6 to 10 hours (preferably 8 hours), reduce the concentration of the liquid in the evaporator of the second evaporation system and reduce the normal liquid level from 40% to 20%, then add water to 60%, while accelerating circulation for 30 minutes. This step not only reduces the concentration of the liquid, reducing sediments caused by excessive concentration, but also further removes potential blockage risks by diluting with water and accelerating circulation; The above technical means significantly reduce the blockage rate of the heating tubes, thereby reducing the number of shutdowns for flushing and boiling tanks due to pipe blockage and extending the production cycle;

[0021] It improved production efficiency and made the nitrate co-production process more stable and reliable;

[0022] II. Optimizing heat transfer efficiency and saving energy; reducing calcium and magnesium content: The calcium and magnesium content in the brine is reduced to 3 ppm / l to 5 ppm / l using calcium lime and flue gas, and the calcium and magnesium content in the evaporator of the second evaporation system is controlled to not exceed 50 ppm; this step effectively reduces the decrease in heat transfer efficiency caused by the deposition of calcium and magnesium impurities; monitoring and control system: Although the document does not directly mention that the technical solution includes a monitoring and control system, based on the needs of actual operation, it can be reasonably inferred that this method may combine a system for real-time monitoring of parameters such as temperature, pressure, and flow rate in the heating tubes, and adjust the operating parameters by automatically measuring the solid-liquid ratio to ensure that the heating tubes operate in the best condition; the above technical means optimize heat transfer efficiency, making heat transfer more efficient, thereby saving energy costs; and reducing the risk of equipment overheating and damage caused by decreased heat transfer efficiency;

[0023] 3. Reduce equipment maintenance and replacement costs; increase circulation and evaporation cycle: by periodically increasing the flow rate and reducing the concentration of the feed liquid, equipment wear and blockage caused by deposit accumulation are reduced; reduce calcium and magnesium content: reduce equipment corrosion and deposit accumulation caused by calcium and magnesium impurities, and extend the service life of the equipment; significantly reduce the frequency and cost of equipment maintenance and replacement; improve the reliability and stability of the equipment, and reduce downtime caused by equipment failure;

[0024] IV. Improving Product Quality and Output: Overall Anti-Blocking Strategy: A complete anti-blocking strategy is formed by comprehensively implementing measures such as speed-up cycles, evaporation cycles, and reducing calcium and magnesium content; Real-time Monitoring and Control System: By combining a real-time monitoring and control system, potential problems can be detected and adjusted in a timely manner, ensuring the stability and continuity of the production process; improving product quality and stability; increasing output, and bringing greater economic benefits to the enterprise;

[0025] In summary, this anti-clogging method for the heating tubes in nitrate co-production has significant beneficial effects. It not only reduces the clogging of the heating tubes and improves production efficiency, but also optimizes heat transfer efficiency, saves energy costs, reduces equipment maintenance and replacement costs, and improves product quality and yield. These beneficial effects work together in the nitrate co-production process, making this method highly valuable in practical applications and promising in the market. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] A method for preventing clogging in heating tubes used in nitrate co-production, such as... Figure 1 As shown, it includes the following steps:

[0030] Step 1, Increased Circulation: Add a circulation pump to the piping of the second evaporation system, and increase the fluid flow rate in the evaporator tank of the second evaporation system by the circulation pump 2 to 4 times a day, raising it to 130% to 160% of the original flow rate. By adding a circulation pump to the piping of the second evaporation system and increasing the fluid flow rate to 130% to 160% (preferably 150%) of the original flow rate 2 to 4 times a day (preferably 3 times), it is possible to effectively avoid the fluid stagnation in the pipes and the formation of deposits due to excessively low flow rate. The higher flow rate can flush away impurities attached to the pipe walls, thereby significantly reducing the blockage of the heating tubes.

[0031] Step 2, Evaporation Circulation: The cubic liquid in the evaporator of the second evaporation system is circulated and evaporated. Every 6 to 10 hours, the concentration of the cubic liquid in the evaporator of the second evaporation system is reduced from 40% to 20%, and then water is added to 60%. Every 6 to 10 hours (preferably 8 hours), the concentration of the liquid in the evaporator of the second evaporation system is reduced from 40% to 20%, and then water is added to 60%, while accelerating the circulation for 30 minutes. This step not only reduces the concentration of the liquid, reducing the sediment caused by excessive concentration, but also further eliminates the potential risk of blockage by diluting with water and accelerating the circulation. The above technical means significantly reduce the blockage rate of the heating tubes, thereby reducing the number of shutdowns for flushing and boiling the tank due to tube blockage and extending the production cycle.

[0032] The process also includes a third step: reducing the calcium and magnesium content. This involves using quicklime and flue gas to lower the calcium and magnesium content in the brine to 3 to 5 ppm / l, ensuring that the calcium and magnesium content in the evaporator of the second evaporation system does not exceed 50 ppm. A calcium and magnesium ion sensor is used to measure the calcium and magnesium concentration in this step. The quicklime and flue gas method utilizes a chemical reaction to convert calcium and magnesium ions in the brine into insoluble precipitates, effectively reducing the calcium and magnesium content. Reducing the calcium and magnesium content in the brine to 3 to 5 ppm / l and ensuring that the calcium and magnesium content in the evaporator of the second evaporation system does not exceed 50 ppm helps to further reduce the blockage of the heating tubes caused by calcium and magnesium deposition. The calcium and magnesium ion sensor monitors the calcium and magnesium concentration in the brine in real time to ensure the effectiveness of the chemical reaction and adjust operating parameters promptly to maintain the calcium and magnesium content within the target range. Through the combined effect of the three steps—accelerated circulation, evaporation circulation, and reduction of calcium and magnesium content—blockage of the heating tubes can be effectively prevented. Acceleration cycles and evaporation cycles reduce the formation and accumulation of sediments through physical scouring and chemical dilution, while reducing calcium and magnesium content reduces sediment production at its source.

[0033] In the speed-up cycle of step one, the steam flow rate to the second evaporation system is reduced to no more than 0.2 MPa. The speed-up cycle increases the fluid velocity in the heating tubes, utilizing the fluid's shear force and scouring effect to reduce impurity deposition on the tube walls. The higher flow rate helps flush away already deposited impurities while preventing new impurities from depositing. Furthermore, reducing the steam flow rate to the second evaporation system to no more than 0.2 MPa reduces steam impact on the tube walls and scaling, further protecting the heating tubes. The speed-up cycle is performed three times per day; this frequency ensures sufficient time for high-speed scouring in the heating tubes without excessively disrupting the normal production process. Adjusting the flow rate to 150% of the original flow rate achieves the scouring effect without placing excessive pressure on the pumps and pipelines.

[0034] In step one, the evaporation cycle is performed three times daily, with the flow rate adjusted to 150% of the original rate. Evaporation cycling reduces the concentration of the liquid in the evaporator, decreasing the solute content in the solution and thus reducing the likelihood of crystallization. Simultaneously, diluting the liquid with water alters the Baumé degree of the solution, further influencing the crystallization process. A lower Baumé degree reduces the supersaturation of the solute in the solution, slowing down the crystallization rate and reducing the risk of pipe blockage. The evaporation cycle interval is 8 hours. This interval ensures sufficient time for the liquid to undergo concentration changes and crystallization during evaporation, while preventing excessively high concentrations that could quickly clog the pipes.

[0035] In step two, the evaporation cycle is spaced 8 hours apart, allowing the Baumé degree to decrease from 27 to 25. This decrease in Baumé degree from 27 to 25 significantly affects the crystallization process of the solution, reducing the likelihood of tube blockage.

[0036] The process also includes step four, real-time monitoring: setting up a sensor group, including temperature sensors, pressure sensors, and flow rate sensors, which monitor the temperature, pressure, and flow rate parameters within the second evaporation system. Changes in these parameters reflect the operating status of the heating tubes and the fluid flow, providing a basis for timely adjustments to operating parameters. When the sensors detect abnormal parameters, the automatic control system can respond quickly and take measures to ensure the stability and safety of the production process.

[0037] In summary, this invention effectively prevents the blockage of heating tubes in the nitrate co-production process by implementing measures such as accelerated circulation, evaporation circulation, reduction of calcium and magnesium content, and real-time monitoring. This improves production efficiency, extends equipment lifespan, reduces production costs, and enhances product quality. Furthermore, this technical solution is logical and feasible, providing strong support for production optimization in nitrate co-production enterprises.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0040] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for preventing blockage in a heating tube for nitrate co-production, characterized in that: Includes the following steps: Step 1, Speed-up Circulation: Add a circulation pump to the pipeline of the second evaporation system, and increase the flow rate of the fluid in the evaporation tank of the second evaporation system by the circulation pump 2 to 4 times a day, increasing it to 130% to 160% of the original flow rate; Step 2, Evaporation Circulation: The cubic liquid in the evaporator of the second evaporation system is circulated and evaporated. Every 6 to 10 hours, the concentration of the cubic liquid in the evaporator of the second evaporation system is reduced, and the normal liquid level in the evaporator of the second evaporation system is reduced from 40% to 20%, and then water is added to 60%.

2. The anti-clogging method for a heating tube in a nitrate co-production plant according to claim 1, characterized in that: It also includes step three, which is to reduce the calcium and magnesium content: the calcium and magnesium content in the brine is reduced by using quicklime and flue gas, so that the calcium and magnesium content is reduced to 3 ppm / l to 5 ppm / l, and the calcium and magnesium content in the evaporator of the second evaporation system does not exceed 50 ppm.

3. The anti-clogging method for a heating tube for nitrate co-production according to claim 2, characterized in that: The device used to measure calcium and magnesium concentration in step three is a calcium and magnesium ion sensor.

4. The anti-clogging method for a heating tube for nitrate co-production according to claim 1, characterized in that: In the growth cycle of step one, the steam inlet flow rate of the second evaporation system is reduced to no more than 0.2 MPa.

5. The anti-clogging method for a heating tube in a nitrate co-production plant according to claim 1, characterized in that: In step one, the rate of increase is cycled three times a day, and the flow rate is adjusted to 150% of the original flow rate.

6. The anti-clogging method for a heating tube for nitrate co-production according to claim 1, characterized in that: The evaporation cycle in step two has an interval of 8 hours, which reduces the Baumé degree from 27 to 25.

7. The anti-clogging method for a heating tube for nitrate co-production according to claim 1, characterized in that: It also includes step four, real-time monitoring: setting up a sensor group, which includes a temperature sensor, a pressure sensor, and a flow rate sensor, and the temperature sensor, pressure sensor, and flow rate sensor respectively monitor the temperature, pressure, and flow rate parameters in the second evaporation system.

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