Urea hydrolysis ammonia production area steam drainage waste heat utilization system

Abstract

The invention discloses a steam drainage waste heat utilization system for a urea hydrolysis ammonia production area, and belongs to the technical field of urea hydrolysis waste heat utilization. The steam drain cooler is connected with the cold storage tank and a steam drain discharge pipeline of the urea hydrolysis ammonia preparation area, and the steam drain cooler is used for heating a cold medium output by the cold storage tank to form a hot medium and then outputting the hot medium, and cooling steam drain output by the steam drain discharge pipeline and then outputting the steam drain; a heat storage tank; the heat release loop is connected with the heat storage tank and the cold storage tank, and the heat release loop is used for conducting heat exchange on the heat medium output by the heat storage tank to form a cold medium and conveying the cold medium back to the cold storage tank to be stored; a high-temperature heat source contained in steam drainage is transferred into the heat storage medium, heat supply is adjusted according to the actual heat demand of each loop during heat release, and the technical problem that the heat supply amount is inconsistent with the heat demand can be solved.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology in urea hydrolysis, and more specifically, to a system for utilizing the hydrophobic waste heat of steam in a urea hydrolysis ammonia production zone. Background Technology

[0002] Currently, both newly built and existing coal-fired power plants in China generally adopt SCR flue gas denitrification technology to remove nitrogen oxides from flue gas. The denitrification reducing agent preparation system upon which SCR flue gas denitrification technology relies is mainly based on the urea hydrolysis ammonia production process. The urea hydrolyzer reaction heating and product gas pipeline heating in the urea hydrolysis ammonia production area generally use low-pressure saturated steam above 180°C as the required heat source. After releasing heat, the low-pressure saturated steam becomes steam condensate, which is collected and recovered through a condensate pipe and stored in a condensate tank for subsequent urea solution preparation in the urea dissolving tank. Excess condensate is sent back to the main plant boiler room. The temperature of the steam condensate entering the condensate tank is generally above 100°C and is in a vapor-liquid mixed state. To prevent the flash steam condensate from generating severe white smoke at the condensate tank exhaust port, a water spray cooling device is often installed inside the condensate tank. Although the above method can effectively solve the white smoke problem, it requires a large amount of desalination cooling water and does not reasonably recover and utilize the waste heat of the condensate in the condensate tank, resulting in a waste of energy.

[0003] In existing urea hydrolysis ammonia production areas, urea dissolving tanks and urea solution tanks are generally equipped with steam heating coils. The steam heating coils consume a portion of the steam to heat the urea solution inside the tanks. The operating temperature of the urea hydrolyzer is generally 130℃ to 160℃, while the temperature of the urea solution entering the urea hydrolyzer is usually less than 50℃. The lower urea solution feed temperature will reduce the reaction rate of the urea hydrolyzer to some extent, and additional steam is required to heat the urea solution to the operating temperature of the urea hydrolyzer.

[0004] Patent application CN115650252A discloses a "Heat Cascade Utilization System and Method for Denitrified Urea Hydrolysis to Ammonia Production". In this application, a portion of the steam condensate emitted from the urea hydrolyzer enters the coil heat exchanger of the urea solution storage tank through a condensate pipe to maintain the storage temperature of the urea solution; a second portion enters the coil heat exchanger of the urea dissolving tank to maintain the dissolving temperature of the urea solution; and a third portion is used for heat tracing of the urea solution conveying pipeline between the urea solution storage tank and the urea hydrolyzer. All the condensate after the heat exchange of the above three portions enters the condensate tank. Although this application recovers and utilizes the heat in the steam condensate, the operating parameters such as the steam condensate flow rate, temperature, and the heat required for heating each process section are constantly changing. Therefore, it is difficult to effectively match and balance the heat supply and heat demand, which inevitably leads to problems of excess or insufficient heat supply, seriously affecting the stable and reliable operation of the urea hydrolysis to ammonia production system. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that the heat supply and demand are unbalanced when steam condensate is directly transported to the heat exchange of each process section, resulting in the inability to fully utilize the heat contained in the steam condensate. Therefore, this invention proposes a waste heat utilization system for steam condensate in the urea hydrolysis ammonia production area.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This application provides a system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone, wherein the system is connected to the urea hydrolysis ammonia production zone; the system includes: A cold storage tank, wherein a cold medium is stored inside the tank. A steam condensate cooler is provided, which is connected to the cold storage tank and the steam condensate discharge pipe of the urea hydrolysis ammonia production area. The steam condensate cooler is used to heat the cold medium output from the cold storage tank to form a hot medium before outputting it, and to cool the steam condensate output from the steam condensate discharge pipe before outputting it. A heat storage tank, wherein the heat storage tank is used to store the heat medium output from the steam trap cooler; A heat release circuit is connected to the heat storage tank and the cold storage tank. The heat release circuit is used to exchange heat with the heat medium output from the heat storage tank to form a cold medium, and to transport the cold medium back to the cold storage tank for storage.

[0007] Furthermore, the heat release circuit is connected to the heat storage tank via a heat medium transport pipeline, and the heat release circuit is connected to the cold storage tank via a cold medium main pipeline; a heat medium transport pump is installed on the heat medium transport pipeline; the heat release circuit includes: a first pipeline, a second pipeline, and a third pipeline.

[0008] Furthermore, one end of the first pipeline is connected to the hot medium conveying pipeline, and the other end is connected to the cold medium main pipeline; the first pipeline is connected to: First manual valve; A first electric valve is used to switch the on / off state between the first pipeline and the heat medium conveying pipeline. Urea dissolving tank; The first electric regulating valve adjusts its opening degree according to the temperature of the urea solution inside the urea dissolving tank. A first check valve is used to prevent the cold medium from flowing back into the urea dissolving tank; The second manual valve is used to switch the on / off state between the first pipeline and the main cold medium pipeline.

[0009] Furthermore, one end of the second pipeline is connected to the hot medium conveying pipeline, and the other end is connected to the cold medium main pipeline; the second pipeline is connected to: Third manual valve; The second electric valve is used to switch the on / off state between the second pipeline and the heat medium conveying pipeline. Urea solution storage tank; The second electric regulating valve adjusts its opening degree according to the temperature of the urea solution inside the urea solution storage tank. The second check valve is used to prevent the cold medium from flowing back into the urea solution storage tank; The fourth manual valve is used to switch the on / off state between the second pipeline and the main cold medium pipeline.

[0010] Furthermore, the urea solution storage tank is connected to a urea solution delivery pipeline, and the urea solution delivery pipeline is equipped with a urea solution delivery pump.

[0011] Furthermore, one end of the third pipeline is connected to the hot medium conveying pipeline, and the other end is connected to the cold medium main pipeline; the third pipeline is connected to: Fifth manual valve; The third electric valve is used to switch the on / off state between the third pipeline and the heat medium conveying pipeline. A urea solution heater, wherein the urea solution heater is connected to the urea solution delivery pipeline; The third electric regulating valve adjusts its opening degree according to the temperature of the urea solution output by the urea solution heater; A third check valve is used to prevent the cold medium from flowing back into the urea solution heater; The sixth manual valve is used to switch the on / off state between the third pipeline and the cold medium main pipeline.

[0012] Furthermore, a thermometer is installed on the cold medium main pipeline, and the hot medium transfer pump is a variable frequency pump, the frequency of which is adjusted according to the measured value of the thermometer.

[0013] Furthermore, a cold medium delivery pipeline is provided between the steam condensate cooler and the cold storage tank, and a cold medium delivery pump is provided on the cold medium delivery pipeline. The cold medium delivery pump is a variable frequency pump, and the frequency of the cold medium delivery pump is adjusted according to the temperature of the steam condensate output by the steam condensate cooler.

[0014] Furthermore, an auxiliary electric heater is installed inside the heat storage tank.

[0015] Furthermore, the steam condensate cooler and the urea solution heater are plate heat exchangers or shell-and-tube heat exchangers.

[0016] The beneficial effects of this invention are as follows: This application provides a waste heat utilization system for steam condensate in a urea hydrolysis ammonia production area. Based on heat storage technology, it smooths out heat peaks and fills valleys, transferring the high-temperature heat source contained in the steam condensate to the heat storage medium. The stored heat is then released through a heat release circuit. During heat release, the heating supply is adjusted according to the actual heat demand of each circuit. This allows the heat to be used to maintain the storage temperature of the urea solution and also to raise the temperature of the urea solution, solving the technical problem of inconsistent heat supply and demand and ensuring full utilization of waste heat. The waste heat utilization system for steam condensate in a urea hydrolysis ammonia production area provided by this application is highly operable, has significant energy-saving and consumption-reducing effects, and has good environmental and economic benefits, with broad application prospects. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a urea hydrolysis ammonia production zone steam hydrophobic waste heat utilization system provided in an embodiment of the present invention.

[0018] The markings in the diagram are as follows: 1. Cold storage tank; 11. Cold medium transfer pump; 12. Thermometer; 2. Steam trap cooler; 3. Thermal storage tank; 31. Auxiliary electric heater; 32. Heat transfer pump; 4. Heat release circuit; 41. First pipeline; 411. First manual valve; 412. First electric valve; 413. First electric regulating valve; 414. Urea dissolving tank; 415. First check valve; 416. Second manual valve; 42. Second pipeline; 421. Third manual valve; 422. Second electric valve; 423. Second electric regulating valve; 424. Urea solution storage tank; 425. Second check valve; 426. Fourth manual valve; 427. Urea solution delivery pipeline; 428. Urea solution delivery pump; 43. Third pipeline; 431. Fifth manual valve; 432. Third electric valve; 433. Third electric regulating valve; 434. Urea solution heater; 435. Third check valve; 436. Sixth manual valve. Detailed Implementation

[0019] 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 a part of the embodiments of the present invention, and not all of the 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.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions 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. When the 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.

[0023] Please see Figure 1 The embodiment of this application shows a waste heat recovery system for steam condensate from a urea hydrolysis ammonia production zone. In practical applications, the waste heat recovery system is connected to the urea hydrolysis ammonia production zone and the urea hydrolyzer. The waste heat recovery system recovers waste heat from the steam condensate discharged from the urea hydrolysis ammonia production zone. On the one hand, it can reduce the temperature of the steam condensate to prevent flash evaporation when the steam condensate enters the condensate tank. On the other hand, it can increase the temperature of the urea solution to reduce the amount of steam consumed in the subsequent urea hydrolysis reaction.

[0024] The steam condensate waste heat utilization system includes: a cold storage tank 1, a steam condensate cooler 2, a heat storage tank 3, and a heat release circuit 4; wherein, the cold storage tank 1 stores a cold medium inside the tank; as one embodiment of this application, it is preferred to use a medium with a large specific heat capacity and low heat transfer resistance, such as water or heat transfer oil, as the cold medium.

[0025] The steam condensate cooler 2 is connected to the cold storage tank 1 via a cold medium conveying pipeline, on which a cold medium conveying pump 11 is installed. The cold medium output from the cold storage tank 1 is pressurized by the cold medium conveying pump 11 and enters the steam condensate cooler 2 along the cold medium conveying pipeline. The steam condensate cooler 2 is also connected to the steam condensate discharge pipeline of the urea hydrolysis ammonia production area. The steam condensate output from the urea hydrolysis ammonia production area is conveyed into the steam condensate cooler 2 along the steam condensate discharge pipeline. The steam condensate contains a portion of the steam formed by flash evaporation. In the steam condensate cooler 2, the cold medium and the steam condensate undergo indirect contact heat exchange. The cold medium recovers the high-temperature heat contained in the steam condensate, causing the steam condensate to cool down from above 100°C to about 90°C. After cooling, the steam condensate is completely cooled into liquid water and output from the steam condensate cooler 2. The liquid water subsequently enters the condensate tank without flash evaporation, thus effectively solving the problem of white smoke coming out of the condensate tank exhaust port. At the same time, there is no need to spray desalination cooling water into the condensate tank, reducing production costs.

[0026] In a preferred embodiment of this application, the cold medium transfer pump 11 is a variable frequency pump, and the frequency of the cold medium transfer pump 11 is adjusted according to the temperature of the steam condensate at the steam condensate outlet on the steam condensate cooler 2; if the steam condensate temperature is higher than the preset value, the cold medium transfer pump 11 controls to appropriately increase the cold medium pumping flow rate, and vice versa.

[0027] The cold medium exchanges heat with the steam condensate in the steam condensate cooler 2 to form a hot medium. The heat storage tank 3 is connected to the steam condensate cooler 2 and is used to store the hot medium output from the steam condensate cooler 2. In the above technical solution, the storage temperature of the hot medium in the heat storage tank 3 is controlled between 75°C and 85°C. As one embodiment of this application, an auxiliary electric heater 31 is provided inside the heat storage tank 3. The auxiliary electric heater 31 only operates when the steam condensate waste heat utilization system is started or when the temperature of the hot medium in the heat storage tank 3 is lower than the preset value. The auxiliary electric heater 31 is used to supplement the heat medium in the heat storage tank 3 with heat. Under other operating conditions, the auxiliary electric heater 31 does not operate.

[0028] The heat release circuit 4 is connected to the heat storage tank 3 via a heat medium conveying pipeline, and the heat release circuit 4 is connected to the cold storage tank 1 via a cold medium main pipeline. A heat medium conveying pump 32 is installed on the heat medium conveying pipeline. The heat medium output from the heat storage tank 3 is pressurized by the heat medium conveying pump 32 and then enters the heat release circuit 4 along the heat medium conveying pipeline. The heat release circuit 4 is used to exchange heat with the heat medium output from the heat storage tank 3 to form a cold medium, and then transport the cold medium back to the cold storage tank 1 for storage. As one embodiment of this application, the heat release circuit 4 is composed of a first pipeline 41, a second pipeline 42, and a third pipeline 43 connected in parallel.

[0029] The heat medium entering the first pipeline 41 is used to maintain the storage temperature of the urea solution. One end of the first pipeline 41 is connected to the heat medium conveying pipeline, and the other end is connected to the cold medium main pipeline. The first pipeline 41 is connected to: a first manual valve 411, a first electric valve 412, a first electric regulating valve 413, a urea dissolving tank 414, a first check valve 415, and a second manual valve 416. After the heat medium enters the heat release circuit 4, it enters the urea dissolving tank 414 along the first pipeline 41 and flows through the heating coil of the urea dissolving tank 414. The heat medium indirectly contacts and exchanges heat with the urea solution in the urea dissolving tank 414 in the heating coil of the urea dissolving tank 414. The heat medium releases heat to heat the urea solution and maintain the temperature of the urea solution in the tank. At 40℃ to 50℃, after heat exchange, the hot medium forms a cold medium that leaves the urea dissolving tank 414 and is transported back to the cold storage tank 1 along the cold medium main pipeline. In the above technical solution, the first manual valve 411 and the first electric valve 412 are used to switch the on / off state between the first pipeline 41 and the hot medium conveying pipeline. The first electric regulating valve 413 automatically adjusts its opening according to the temperature of the urea solution in the urea dissolving tank 414, and adjusts the heat exchange by changing the flow rate of the hot medium in the heating coil, thereby realizing dynamic control of the temperature of the urea solution in the urea dissolving tank 414. The first check valve 415 is used to prevent the cold medium from flowing back into the heating coil in the urea dissolving tank 414. The second manual valve 416 is used to switch the on / off state between the first pipeline 41 and the cold medium main pipeline.

[0030] The heat medium entering the second pipeline 42 is used to maintain the storage temperature of the urea solution. One end of the second pipeline 42 is connected to the heat medium conveying pipeline, and the other end is connected to the cold medium main pipeline. The second pipeline 42 is connected to: a third manual valve 421, a second electric valve 422, a second electric regulating valve 423, a urea solution storage tank 424, a second check valve 425, and a fourth manual valve 426. After entering the heat release circuit 4, the heat medium enters the urea solution storage tank 424 along the second pipeline 42 and flows through the heating coil of the urea solution storage tank 424. The heat medium indirectly contacts and exchanges heat with the urea solution inside the urea solution storage tank 424 in the heating coil, releasing heat to heat the urea solution and maintain the temperature of the urea solution inside the tank at a certain level. At temperatures ranging from 40°C to 50°C, the heat medium exchanges heat to form a cold medium that leaves the urea solution storage tank 424 and flows into the cold medium main pipeline for transport back to the cold storage tank 1. In the above technical solution, the third manual valve 421 and the second electric valve 422 are used to switch the on / off state between the second pipeline 42 and the heat medium conveying pipeline. The second electric regulating valve 423 automatically adjusts its opening according to the temperature of the urea solution in the urea solution storage tank 424, and adjusts the heat exchange by changing the flow rate of the heat medium in the heating coil, thereby realizing dynamic control of the urea solution temperature in the urea solution storage tank 424. The second check valve 425 is used to prevent the cold medium from flowing back into the heating coil in the urea solution storage tank 424. The fourth manual valve 426 is used to switch the on / off state between the second pipeline 42 and the cold medium main pipeline.

[0031] In one embodiment of this application, the urea solution storage tank 424 and the urea hydrolyzer are connected by a urea solution delivery pipeline 427, and a urea solution delivery pump 428 is installed on the urea solution delivery pipeline 427; the urea solution stored in the urea solution storage tank 424 is pressurized by the urea solution delivery pump 428 and then enters the urea hydrolyzer for reaction along the urea solution delivery pipeline 427. The heat medium entering the third pipeline 43 is used to raise the feed temperature of the urea solution to the urea hydrolyzer. One end of the third pipeline 43 is connected to the heat medium conveying pipeline, and the other end is connected to the cold medium main pipeline. The third pipeline 43 is connected to: a fifth manual valve 431, a third electric valve 432, a third electric regulating valve 433, a urea solution heater 434, a third check valve 435, and a sixth manual valve 436. The urea solution heater 434 is connected to the urea solution conveying pipeline 427. The urea solution flows along the urea solution conveying pipeline 427, passes through the urea solution heater 434 for heating, and is then sent to the urea hydrolyzer. After entering the exothermic circuit 4, the heat medium enters the urea solution heater 434 along the third pipeline 43, where it indirectly contacts and exchanges heat with the urea solution, utilizing the heat medium as... The urea solution heater 434 heats the urea solution, ensuring its temperature is between 70°C and 80°C before entering the urea hydrolyzer. This increases the reaction rate of the urea solution in the hydrolyzer and reduces the steam consumption during the heating reaction. After heat exchange, the hot medium forms a cold medium that leaves the urea solution heater 434 and flows into the cold medium main pipeline back to the cold storage tank 1 for storage. In the above technical solution, the fifth manual valve 431 and the third electric valve 432 are used to switch the on / off state between the third pipeline 43 and the hot medium conveying pipeline. The third electric regulating valve 433 automatically adjusts its opening according to the temperature of the urea solution after heat exchange. The third check valve 435 is used to prevent the cold medium from flowing back into the urea solution heater 434. The sixth manual valve 436 is used to switch the on / off state between the third pipeline 43 and the cold medium main pipeline.

[0032] In the above technical solution, a thermometer 12 is installed on the cold medium main pipeline to measure the temperature of the cold medium before it enters the cold storage tank 1; the hot medium transfer pump 32 is a variable frequency pump, and the frequency of the hot medium transfer pump 32 is adjusted according to the measurement value of the thermometer 12 so that the temperature of the cold medium before it enters the cold storage tank 1 is between 50°C and 60°C.

[0033] As a preferred embodiment of this application, the steam condensate cooler 2 and the urea solution heater 434 can be plate heat exchangers or shell-and-tube heat exchangers with a design heat exchange end difference of not less than 5°C.

[0034] This application provides a waste heat utilization system for steam condensate in a urea hydrolysis ammonia production area. Based on heat storage technology, it smooths out heat peaks and fills valleys, transferring the high-temperature heat source contained in the steam condensate to the heat storage medium. The stored heat is then released through a heat release circuit 4. During heat release, the heating supply is adjusted according to the actual heat demand of each circuit. This allows the heat to be used to maintain the storage temperature of the urea solution and also to raise the temperature of the urea solution, solving the technical problem of inconsistent heat supply and demand and ensuring full utilization of waste heat. The waste heat utilization system for steam condensate in a urea hydrolysis ammonia production area provided by this application is highly operable, has significant energy-saving and consumption-reducing effects, and has good environmental and economic benefits, with broad application prospects.

[0035] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone, wherein the system is connected to the urea hydrolysis ammonia production zone; characterized in that, The steam-hydrophobic waste heat recovery system includes: A cold storage tank, wherein a cold medium is stored inside the tank. A steam condensate cooler is provided, which is connected to the cold storage tank and the steam condensate discharge pipe of the urea hydrolysis ammonia production area. The steam condensate cooler is used to heat the cold medium output from the cold storage tank to form a hot medium before outputting it, and to cool the steam condensate output from the steam condensate discharge pipe before outputting it. A heat storage tank, wherein the heat storage tank is used to store the heat medium output from the steam trap cooler; A heat release circuit is connected to the heat storage tank and the cold storage tank. The heat release circuit is used to exchange heat with the heat medium output from the heat storage tank to form a cold medium, and to transport the cold medium back to the cold storage tank for storage.

2. The urea hydrolysis ammonia production zone steam hydrophobic waste heat utilization system according to claim 1, characterized in that, The heat release circuit is connected to the heat storage tank via a heat medium transport pipeline, and the heat release circuit is connected to the cold storage tank via a cold medium main pipeline; a heat medium transport pump is installed on the heat medium transport pipeline; the heat release circuit includes: a first pipeline, a second pipeline, and a third pipeline.

3. The urea hydrolysis ammonia production zone steam hydrophobic waste heat utilization system according to claim 2, characterized in that, One end of the first pipeline is connected to the hot medium conveying pipeline, and the other end is connected to the cold medium main pipeline; the first pipeline is connected to: First manual valve; A first electric valve is used to switch the on / off state between the first pipeline and the heat medium conveying pipeline. Urea dissolving tank; The first electric regulating valve adjusts its opening degree according to the temperature of the urea solution inside the urea dissolving tank. A first check valve is used to prevent the cold medium from flowing back into the urea dissolving tank; The second manual valve is used to switch the on / off state between the first pipeline and the main cold medium pipeline.

4. The urea hydrolysis ammonia production zone steam hydrophobic waste heat utilization system according to claim 2, characterized in that, One end of the second pipeline is connected to the hot medium conveying pipeline, and the other end is connected to the cold medium main pipeline; the second pipeline is connected to: Third manual valve; The second electric valve is used to switch the on / off state between the second pipeline and the heat medium conveying pipeline. Urea solution storage tank; The second electric regulating valve adjusts its opening degree according to the temperature of the urea solution inside the urea solution storage tank. The second check valve is used to prevent the cold medium from flowing back into the urea solution storage tank; The fourth manual valve is used to switch the on / off state between the second pipeline and the main cold medium pipeline.

5. A system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone according to claim 4, characterized in that, The urea solution storage tank is connected to a urea solution delivery pipeline, and the urea solution delivery pipeline is equipped with a urea solution delivery pump.

6. A waste heat recovery system for steam in a urea hydrolysis ammonia production zone according to claim 5, characterized in that, One end of the third pipeline is connected to the hot medium conveying pipeline, and the other end is connected to the cold medium main pipeline; the third pipeline is connected to: Fifth manual valve; The third electric valve is used to switch the on / off state between the third pipeline and the heat medium conveying pipeline. A urea solution heater, wherein the urea solution heater is connected to the urea solution delivery pipeline; The third electric regulating valve adjusts its opening degree according to the temperature of the urea solution output by the urea solution heater; A third check valve is used to prevent the cold medium from flowing back into the urea solution heater; The sixth manual valve is used to switch the on / off state between the third pipeline and the cold medium main pipeline.

7. A system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone according to claim 2, characterized in that, A thermometer is installed on the cold medium main pipeline, and the hot medium transfer pump is a variable frequency pump. The frequency of the hot medium transfer pump is adjusted according to the measurement value of the thermometer.

8. A system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone according to claim 1, characterized in that, A cold medium delivery pipeline is provided between the steam condensate cooler and the cold storage tank. A cold medium delivery pump is provided on the cold medium delivery pipeline. The cold medium delivery pump is a variable frequency pump, and the frequency of the cold medium delivery pump is adjusted according to the temperature of the steam condensate output by the steam condensate cooler.

9. A system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone according to claim 1, characterized in that, An auxiliary electric heater is installed inside the heat storage tank.

10. A system for utilizing the waste heat from steam condensation in a urea hydrolysis ammonia production zone according to claim 6, characterized in that, The steam condensate cooler and the urea solution heater are plate heat exchangers or shell-and-tube heat exchangers.

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