Energy-saving urea production system

Abstract

The invention relates to the technical field of urea preparation, and particularly discloses an energy-saving urea production system which is characterized in that a carbon dioxide stripping tower and a high-pressure ammonia ejector are respectively connected with a first high-pressure methylamine condenser, and a second high-pressure methylamine condenser is connected between the first high-pressure methylamine condenser and a urea synthesis tower; the second high-pressure methylamine condenser can be externally connected with a carbon dioxide compressor, and the urea synthesis tower is connected with the upper part of the carbon dioxide stripping tower so as to input a urea mixture into the carbon dioxide stripping tower. According to the energy-saving urea production system, the second high-pressure methylamine condenser is additionally arranged, so that the recovery rate and the utilization rate of synthetic reaction heat are improved.

Description

Technical Field

[0001] The invention relates to the technical field of urea preparation, and in particular to an energy-saving urea production system. Background Art

[0002] The raw materials for urea production mainly include coal or natural gas, air and water vapor. After a series of treatments, coal and natural gas can be converted into synthetic ammonia and carbon dioxide, which are the key raw materials for urea production. The synthesis reaction of urea is a balanced chemical reaction, which is generally believed to be completed in two steps: excess liquid ammonia reacts with carbon dioxide to form ammonium carbamate; ammonium carbamate is heated to form urea.

[0003] The Chinese patent document with the authorization announcement number CN107001247B discloses a urea production device, including a reactor, a stripper, a condenser and a scrubber, wherein the reactor, the stripper, the condenser and the scrubber are connected end to end, and the condenser and the reactor are connected separately. Ammonia is supplied to the condenser and carbon dioxide is supplied to the stripper, and the carbon dioxide after stripping enters the condenser and synthesizes with ammonia to form ammonium carbamate, referred to as methylammonium. The synthesis reaction is an exothermic reaction, and the condenser absorbs the heat released to achieve heat recovery and reuse. Then the methylammonium mixture enters the reactor and is heated to generate urea and water. Then the urea-containing aqueous solution is concentrated in the stripper to achieve material recycling.

[0004] However, the above-mentioned urea production device is only provided with a single condenser to utilize the synthesis reaction heat, which easily results in a low recovery rate and utilization rate of the synthesis reaction heat. Summary of the invention

[0005] The present invention provides an energy-saving urea production system, aiming to solve the problem of low recovery rate and utilization rate of synthesis reaction heat in the related art.

[0006] The energy-saving urea production system of the present invention comprises a carbon dioxide stripping tower, a first high-pressure methylammonium condenser, a high-pressure ammonia injector and a urea synthesis tower, characterized in that the carbon dioxide stripping tower and the high-pressure ammonia injector are respectively connected to the first high-pressure methylammonium condenser, a second high-pressure methylammonium condenser is connected between the first high-pressure methylammonium condenser and the urea synthesis tower, the second high-pressure methylammonium condenser can be externally connected to a carbon dioxide compressor, and the urea synthesis tower is connected to the upper part of the carbon dioxide stripping tower to input a urea mixture into the carbon dioxide stripping tower.

[0007] Preferably, the energy-saving urea production system also includes a high-pressure scrubber, which has a gas inlet and a gas outlet, and the gas inlet is connected to the top of the urea synthesis tower; the high-pressure scrubber is connected to a high-pressure methylammonium pump, and the high-pressure scrubber also has a methylammonium liquid outlet, and the methylammonium liquid outlet is connected to the high-pressure ammonia injector.

[0008] Preferably, the second high-pressure methylammonium condenser includes a shell and a condenser tube, the shell is divided into a water inlet chamber, a condensation chamber and a water outlet chamber in sequence along the left-right direction, the cavity wall of the condensation chamber is provided with a reactant inlet and a reactant outlet which are opposite to each other up and down and staggered left and right, the reactant inlet is connected to the first high-pressure methylammonium condenser, and the reactant outlet is connected to the urea synthesis tower; a plurality of the condenser tubes are arranged in the condensation chamber, and the two ends are respectively connected to the water inlet chamber and the water outlet chamber.

[0009] Preferably, the shell has a first partition for separating the water inlet chamber and the condensation chamber and a second partition for separating the condensation chamber and the water outlet chamber. The first partition and the second partition are both rotatably assembled on the shell, and the two ends of the condensation tube are respectively fixedly connected to the first partition and the second partition; the shell is provided with a driving device for driving at least one of the first partition and the second partition to rotate.

[0010] Preferably, a scraper capable of sliding along the axial direction is provided in the condenser, and the scraper is used to scrape off scale in the condenser during sliding. A transmission assembly is connected between the scraper and the shell so that the scraper can slide during revolution.

[0011] Preferably, the scraper member comprises a scraper ring, the outer circumferential surface of the scraper ring is in contact with the inner wall of the condenser tube, and the scraper ring is provided with a plurality of water holes.

[0012] Preferably, the transmission assembly includes a threaded guide and a gear mechanism, the threaded guide is coaxially rotatably arranged in the condenser, and the center hole of the scraper ring is threadedly sleeved on the threaded guide; the gear mechanism connects the threaded guide and the housing, and the gear mechanism is used to drive the threaded guide to rotate when the threaded guide revolves.

[0013] Preferably, the transmission assembly further comprises a guide rod, wherein the guide rod is disposed in the condenser tube and extends in the axial direction of the condenser tube, and the scraper ring is slidably connected to the guide rod.

[0014] Preferably, a mounting plate is provided in the water outlet cavity, the mounting plate is fixedly connected to the second partition plate, one end of the threaded guide is rotatably mounted on the mounting plate, and one end of the guide rod is fixedly mounted on the mounting plate.

[0015] Preferably, the gear mechanism includes a transmission gear ring and a transmission gear, the multiple condenser tubes form a multiple distribution circles from the inside out, the transmission gear ring is arranged with multiple gears from the inside out, the multiple transmission gear rings and the multiple distribution circles correspond to each other, the transmission gear ring is fixed on the shell; the transmission gear is arranged at the other end of the threaded guide and meshes with the adjacent transmission gear ring.

[0016] By adopting the above technical solution, the beneficial effects of the present invention are as follows: 1. The present invention realizes further synthesis of the intermediate product methylammonium and further formation and collection of synthesis reaction heat by adding a second high-pressure methylammonium condenser, thereby increasing the subsequent generation of urea and improving the recovery rate and utilization rate of the synthesis reaction heat.

[0017] 2. The present invention uses the revolution of the condenser tube to stir the gas-liquid mixture, thereby accelerating the contact and collision between the gas molecules and the liquid molecules in the gas-liquid mixture, thereby promoting the mass transfer process of carbon dioxide and ammonia, allowing them to participate in the reaction more fully, thereby increasing the generation rate of methylammonium and the purity of methylammonium. In addition, the revolving condenser tube can also alternately exchange heat with the gas-liquid mixture, so that the heat of the synthesis reaction is quickly dispersed to the entire reaction system, avoiding the occurrence of local overheating, thereby maintaining the uniformity of the reaction temperature.

[0018] 3. The present invention realizes automatic scraping of scale on the inner wall of the condenser tube through the sliding of the scraper ring, thereby ensuring the heat exchange effect of the condenser tube. Since the outer cylindrical surface of the scraper ring fits the inner wall of the condenser tube, the scraper ring has a supporting effect on the condenser tube, thereby reducing the deformation and collapse of the heat exchange tube, and realizing proper protection of the heat exchange tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of equipment of the energy-saving urea production system of the present invention.

[0020] Figure 2 It is a cross-sectional schematic diagram of the second high-pressure methylammonium condenser of the present invention.

[0021] Figure 3 The present invention Figure 2 A magnified schematic diagram of center A.

[0022] Figure 4 It is a three-dimensional schematic diagram of the first partition to the second partition portion of the present invention.

[0023] Figure 5 It is an exploded schematic diagram of the condenser to the threaded guide part of the present invention.

[0024] Figure 6 It is a schematic structural diagram of the gear mechanism part of the present invention.

[0025] Reference numerals: 100. Carbon dioxide stripping tower; 200. The first high-pressure methylammonium condenser; 300. High-pressure ammonia injector; 400, urea synthesis tower; 401, overflow pipe; 500, high pressure scrubber; 501, gas inlet; 502, gas outlet; 503, methylammonium liquid outlet; 600. Carbon dioxide compressor; 700. The second high-pressure methylammonium condenser; 1. Shell; 11. Water inlet chamber; 111. Water inlet; 112. Water outlet; 12. Condensation chamber; 121. Reactant inlet; 122. Reactant outlet; 13. Water outlet chamber; 131. Mounting plate; 14. First baffle; 15. Second baffle; 2. Condenser; 31. Drive motor; 32. Drive gear; 33. Drive gear ring; 4. Scraper ring; 41. Water hole; 51. Threaded guide; 52. Guide rod; 53. Drive gear ring; 54. Drive gear. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0027] Combine the following Figures 1 to 6 The energy-saving urea production system of the present invention is described.

[0028] like Figure 1 As shown, the energy-saving urea production system of the present invention includes a carbon dioxide stripping tower 100, a first high-pressure methylammonium condenser 200, a high-pressure ammonia injector 300, a urea synthesis tower 400, and a high-pressure scrubber 500.

[0029] The top of the carbon dioxide stripping tower 100 and the top of the high-pressure ammonia injector 300 are respectively connected to the top of the first high-pressure methylammonium condenser 200. The bottom of the carbon dioxide stripping tower 100 is externally connected to a carbon dioxide compressor 600, which is used to introduce carbon dioxide gas into the carbon dioxide stripping tower 100, and the carbon dioxide gas enters the first high-pressure methylammonium condenser 200 through the top of the carbon dioxide stripping tower 100; the high-pressure ammonia injector 300 is used to input liquid ammonia into the first high-pressure methylammonium condenser 200, and ammonia and carbon dioxide react in the first high-pressure methylammonium condenser 200 to generate ammonium carbamate and release heat, thereby realizing the first step of ammonium carbamate, i.e., the preparation of methylammonium. The heat of the synthesis reaction is absorbed by the condensing medium in the first high-pressure methylammonium condenser 200 as a heating heat source for the medium-pressure decomposition system.

[0030] A second high-pressure methylammonium condenser 700 is connected between the first high-pressure methylammonium condenser 200 and the urea synthesis tower 400, and the second high-pressure methylammonium condenser 700 can be externally connected to a carbon dioxide compressor 600. The gas-liquid mixture after the reaction in the first high-pressure methylammonium condenser 200 enters the second high-pressure methylammonium condenser 700, and the carbon dioxide compressor 600 simultaneously introduces carbon dioxide gas into the second high-pressure methylammonium condenser 700, whereby the remaining ammonia and carbon dioxide gas in the gas-liquid mixture further react to continue to generate methylammonium, and the heat of the synthesis reaction is absorbed by the condensing medium in the second high-pressure methylammonium condenser 700 as a heating heat source for the low-pressure decomposition system. It should be noted that the carbon dioxide gas introduced into the carbon dioxide stripping tower 100 and the second high-pressure methylammonium condenser 700 by the carbon dioxide compressor 600 can be diverted in proportion. For example, the carbon dioxide gas entering the carbon dioxide stripping tower 100 accounts for 85%, and the carbon dioxide gas entering the second high-pressure methylammonium condenser 700 accounts for 15%. This can ensure the adequacy of the reaction in the first high-pressure methylammonium condenser 200 and the second high-pressure methylammonium condenser 700.

[0031] Afterwards, the gas-liquid mixture (temperature of about 183° C.) in the second high-pressure methylammonium condenser 700 enters the urea synthesis tower 400 and is heated to decompose methylammonium into urea and water.

[0032] An overflow pipe 401 is inserted in the urea synthesis tower 400, and the bottom of the overflow pipe 401 is connected to the upper part of the carbon dioxide stripping tower 100. After the reaction, the gas-liquid mixture of the urea synthesis tower 400 contains unreacted reactants, products after the reaction, and products of other reactions, etc. The liquid components, such as urea, water, and methylammonium, enter the upper part of the carbon dioxide stripping tower 100 through the overflow pipe 401, and transfer heat and mass with the rising carbon dioxide gas. Under the stripping effect of the carbon dioxide gas and the heating and decomposition of the external steam, the unreacted substances are decomposed, which promotes the continued generation of urea. The urea synthesis liquid (containing urea, water, and methylammonium) exiting the carbon dioxide stripping tower 100 enters the medium-pressure decomposition system or the low-pressure decomposition system after decompression to continue decomposition, thereby achieving further decomposition of methylammonium and fully utilizing the synthesis reaction heat in the first high-pressure methylammonium condenser 200 and the second high-pressure methylammonium condenser 700. The post-treatment part of the urea synthesis liquid is a well-known technology in the art and will not be repeated here.

[0033] As can be seen from the above, by adding the second high-pressure methylammonium condenser 700, further synthesis of the intermediate product methylammonium and further formation and collection of synthesis reaction heat are achieved, which not only increases the subsequent urea production, but also improves the recovery rate and utilization rate of the synthesis reaction heat.

[0034] The high pressure washer 500 has a gas inlet 501 and a gas outlet 502, wherein the gas inlet 501 is connected to the top of the urea synthesis tower 400. The high pressure washer 500 is connected to a high pressure methylammonium pump and has a methylammonium liquid outlet 503, which is connected to the high pressure ammonia injector 300.

[0035] After the reaction, the gas components in the urea synthesis tower 400, such as ammonia, carbon dioxide, hydrogen, and nitrogen (temperature is about 170°C), enter the high-pressure scrubber 500 from the top of the urea synthesis tower 400 and the gas inlet 501, and are contacted and washed with the methylammonium liquid from the high-pressure methylammonium pump, thereby removing ammonia and carbon dioxide in the gas phase. Afterwards, the remaining gas components are discharged from the gas outlet 502 and post-processed, while the methylammonium liquid flows into the high-pressure ammonia injector 300 through the methylammonium liquid outlet 503, and enters the first high-pressure methylammonium condenser 200 together with the liquid ammonia sprayed from the high-pressure ammonia injector 300, and then participates in the subsequent reaction, thereby improving the utilization rate of the methylammonium liquid, residual ammonia and carbon dioxide.

[0036] It can be understood that the connection between the above-mentioned devices is pipeline connection, which facilitates the circulation of various chemical materials.

[0037] Continue to refer Figures 1 to 3 The second high-pressure methylammonium condenser 700 includes a shell 1 and a condenser 2. The shell 1 is divided into a water inlet chamber 11, a condensation chamber 12 and a water outlet chamber 13 in sequence along the left-right direction. The wall of the condensation chamber 12 is provided with a reactant inlet 121 and a reactant outlet 122 which are opposite to each other and staggered left and right. The reactant inlet 121 is connected to the first high-pressure methylammonium condenser 200, and the reactant outlet 122 is connected to the urea synthesis tower 400. A plurality of condensers 2 are evenly arranged in the condensation chamber 12. The condensers 2 extend along the left-right direction and the two ends are respectively connected to the water inlet chamber 11 and the water outlet chamber 13. The left and right ends of the shell 1 are respectively provided with a water inlet 111 and a water outlet 112. The water inlet 111 is connected to the water inlet chamber 11, and the water outlet 112 is connected to the water outlet chamber 13.

[0038] In this embodiment, the condensing medium of the second high-pressure methylammonium condenser 700 is cooling water, which enters the water inlet chamber 11 through the water inlet 111, is divided and enters multiple condensing tubes 2, and then merges through the water outlet chamber 13 and is discharged through the water outlet 112. At the same time, the gas-liquid mixture of the first high-pressure methylammonium condenser 200 enters the condensing chamber 12 through the reactant inlet 121, and is discharged through the reactant outlet 122. When the cooling water circulates in the condensing tube 2, it can exchange heat with the gas-liquid mixture, thereby realizing the condensation of the gas-liquid mixture during the reaction, and recovering the synthesis reaction heat for its reuse.

[0039] Continue to refer Figures 2 to 4The housing 1 has a first partition 14 for separating the water inlet chamber 11 and the condensation chamber 12 and a second partition 15 for separating the condensation chamber 12 and the water outlet chamber 13. The first partition 14 and the second partition 15 are both rotatably assembled on the housing 1. The two ends of the condensation tube 2 are respectively fixedly connected to the first partition 14 and the second partition 15. The first partition 14 and the second partition 15 support the condensation tube 2. The housing 1 is provided with a driving device for driving the first partition 14 to rotate.

[0040] When the first partition 14 rotates, the second partition 15 is driven to rotate through the condenser tube 2. Thus, the revolution of the condenser tube 2 is realized, and when the gas-liquid mixture enters the condensation chamber 12, it will first be deposited at the bottom of the condensation chamber 12 due to the action of gravity. The revolving condenser tube 2 can stir the gas-liquid mixture, thereby accelerating the contact and collision between the gas molecules and the liquid molecules in the gas-liquid mixture, thereby promoting the mass transfer process of carbon dioxide and ammonia, so that they can participate in the reaction more fully. Through stirring, the collision frequency between the reactant molecules increases, which helps to accelerate the reaction kinetics and increase the generation rate of methylammonium; stirring can promote the full reaction between the reactants, thereby improving the purity of methylammonium. In addition, the revolving condenser tube 2 can also alternately exchange heat with the gas-liquid mixture, so that the heat of the synthesis reaction is quickly dispersed to the entire reaction system, avoiding the occurrence of local overheating, thereby maintaining the uniformity of the reaction temperature.

[0041] The driving device includes a driving motor 31, a driving gear 32 and a driving ring gear 33. The driving ring gear 33 is coaxially fixed on the first partition 14, and the driving gear 32 is meshed with the driving ring gear 33. The driving motor 31 is installed on the shell 1 and connected to the driving gear 32 to drive the driving gear 32 to rotate.

[0042] When the driving gear 32 rotates, it drives the driving gear ring 33 to rotate under the meshing action, and the driving gear ring 33 drives the first partition plate 14 to rotate, thereby realizing the revolution of the condenser tube 2.

[0043] After the second high-pressure methylammonium condenser 700 is used for a long time, scale will continue to accumulate on the inner wall of the condenser tube 2, thereby affecting the heat exchange effect.

[0044] To this end, continue to refer to Figures 2 to 5, a scraper member capable of sliding along the axial direction is provided in the condenser tube 2, and the scraper member includes a scraper ring 4, the outer circumferential surface of the scraper ring 4 is in contact with the inner wall of the condenser tube 2, and a plurality of water holes 41 evenly distributed along the circumference of the scraper ring 4 are provided on the scraper ring 4, and the water holes 41 are used to pass cooling water to prevent the cooling water from being blocked in the condenser tube 2. When the scraper ring 4 slides, the scraper ring 4 can scrape off the scale on the inner wall of the condenser tube 2, and the scraped scale is carried out by the water flow in the condenser tube 2, thereby cleaning the scale, thus ensuring the heat exchange effect of the condenser tube 2. In addition, since the outer circumferential surface of the scraper ring 4 is in contact with the inner wall of the condenser tube 2, the scraper ring 4 has a supporting effect on the condenser tube 2. During long-term use, the condenser tube 2 will generate thermal stress due to the temperature difference between the materials inside and outside the tube. The long-term thermal stress may cause the heat exchange tube to deform, thereby causing collapse and other phenomena, and the supporting effect of the scraper ring 4 on the condenser tube 2 reduces the deformation and collapse of the heat exchange tube, thereby achieving appropriate protection of the heat exchange tube.

[0045] A transmission assembly is connected between the scraper and the housing 1 , and the transmission assembly includes a threaded guide 51 , a guide rod 52 and a gear mechanism.

[0046] The threaded guide 51 is coaxially arranged in the condenser 2 and forms an annular gap with the condenser 2. In this way, the threaded guide 51 occupies the axial position of the condenser 2, so that the cooling water can only flow in the annular gap, making the cooling water closer to the tube wall of the condenser 2, thereby improving the heat exchange effect of the cooling water and improving the utilization rate of the cooling water. The center hole of the scraper ring 4 is threadedly sleeved on the threaded guide 51, thereby the scraper ring 4 and the spiral guide are threadedly connected. The guide rod 52 is arranged in the condenser 2 and extends in the axial direction of the condenser 2. It can be understood that the guide rod 52 is located beside the threaded guide 51. One of the water holes 41 of the scraper ring 4 constitutes a sliding hole, and the sliding hole is slidably sleeved on the guide rod 52, thereby realizing the sliding connection between the scraper ring 4 and the guide rod 52.

[0047] A mounting plate 131 is provided in the water outlet chamber 13, and the mounting plate 131 is fixedly connected to the second partition plate 15 via a connecting column. One end of the threaded guide 51 is rotatably mounted on the mounting plate 131, and one end of the guide rod 52 is fixedly mounted on the mounting plate 131. The mounting plate 131 is used to provide a mounting position for the threaded guide 51 and the guide rod 52.

[0048] When the threaded guide 51 rotates, due to the effect of the threaded connection, the scraper ring 4 may rotate synchronously with the threaded guide 51, or may slide relatively along the axial direction of the threaded guide 51. However, under the guidance restriction of the guide rod 52, the scraper ring 4 can only slide along the axial direction of the threaded guide 51, so that the scraper ring 4 slides in the condenser tube 2, and the scale on the tube wall is scraped off.

[0049] Continue to refer Figures 4 to 6The gear mechanism connects the threaded guide 51 and the housing 1, and the gear mechanism includes a transmission gear ring 53 and a transmission gear 54. The plurality of condenser tubes 2 form a plurality of distribution circles from the inside to the outside, and the transmission gear ring 53 is arranged with a plurality of distribution circles from the inside to the outside. The plurality of transmission gear rings 53 and the plurality of distribution circles correspond to each other, and the diameters of the transmission gear rings 53 and the corresponding distribution circles are substantially the same. The transmission gear rings 53 are fixed on the housing 1. The transmission gear 54 is arranged at the other end of the threaded guide 51 and meshes with the adjacent transmission gear rings 53.

[0050] When the condenser 2 revolves, the second partition plate 15 and the mounting plate 131 drive the threaded guide 51 to revolve, and the threaded guide 51 drives the transmission gear 54 to revolve. Under the meshing action of the transmission gear 54 and the transmission gear ring 53, the transmission gear 54 rotates by itself, thereby driving the threaded guide 51 to revolve by itself. When the threaded guide 51 rotates by itself, the scraper ring 4 can slide, thereby removing scale. This arrangement realizes the linkage between the scale removal action and the revolving stirring action of the condenser 2, reduces the use of power equipment, and saves costs.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0052] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0053] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An energy-saving urea production system, comprising a carbon dioxide stripping tower (100), a first high-pressure methylammonium condenser (200), a high-pressure ammonia ejector (300) and a urea synthesis tower (400), characterized in that: The carbon dioxide stripping tower (100) and the high-pressure ammonia injector (300) are respectively connected to the first high-pressure methylammonium condenser (200); a second high-pressure methylammonium condenser (700) is connected between the first high-pressure methylammonium condenser (200) and the urea synthesis tower (400); the second high-pressure methylammonium condenser (700) can be externally connected to a carbon dioxide compressor (600); and the urea synthesis tower (400) is connected to the upper part of the carbon dioxide stripping tower (100) so as to input a urea mixture into the carbon dioxide stripping tower (100).

2. The energy-saving urea production system according to claim 1, characterized in that: The energy-saving urea production system further comprises a high-pressure scrubber (500), wherein the high-pressure scrubber (500) has a gas inlet (501) and a gas outlet (502), wherein the gas inlet (501) is connected to the top of the urea synthesis tower (400); the high-pressure scrubber (500) is connected to a high-pressure methylammonium pump, and the high-pressure scrubber (500) further comprises a methylammonium liquid outlet (503), wherein the methylammonium liquid outlet (503) is connected to the high-pressure ammonia injector (300).

3. The energy-saving urea production system according to claim 1, characterized in that: The second high-pressure methylammonium condenser (700) comprises a shell (1) and a condensing tube (2); the shell (1) is divided into a water inlet chamber (11), a condensing chamber (12) and a water outlet chamber (13) in sequence along the left-right direction; the wall of the condensing chamber (12) is provided with a reactant inlet (121) and a reactant outlet (122) which are opposite to each other in the upper and lower directions and staggered in the left and right directions; the reactant inlet (121) is connected to the first high-pressure methylammonium condenser (200), and the reactant outlet (122) is connected to the urea synthesis tower (400); a plurality of condensing tubes (2) are arranged in the condensing chamber (12), and the two ends thereof are respectively connected to the water inlet chamber (11) and the water outlet chamber (13).

4. The energy-saving urea production system according to claim 3, characterized in that: The shell (1) has a first partition (14) for separating the water inlet chamber (11) and the condensation chamber (12) and a second partition (15) for separating the condensation chamber (12) and the water outlet chamber (13); the first partition (14) and the second partition (15) are both rotatably mounted on the shell (1); the two ends of the condensation tube (2) are respectively fixedly connected to the first partition (14) and the second partition (15); and the shell (1) is provided with a driving device for driving at least one of the first partition (14) and the second partition (15) to rotate.

5. The energy-saving urea production system according to claim 4, characterized in that: The condenser tube (2) is provided with a scraper member capable of sliding along its axial direction, the scraper member being used to scrape off scale in the condenser tube (2) during sliding, and a transmission assembly is connected between the scraper member and the housing (1) so that the scraper member can slide during orbital movement.

6. The energy-saving urea production system according to claim 5, characterized in that: The scraper member comprises a scraper ring (4), the outer circumferential surface of the scraper ring (4) is in contact with the inner wall of the condenser tube (2), and the scraper ring (4) is provided with a plurality of water holes (41).

7. The energy-saving urea production system according to claim 6, characterized in that: The transmission assembly comprises a threaded guide (51) and a gear mechanism; the threaded guide (51) is coaxially rotatably arranged in the condenser (2); the center hole of the scraper ring (4) is threadedly sleeved on the threaded guide (51); the gear mechanism connects the threaded guide (51) and the housing (1), and the gear mechanism is used to drive the threaded guide (51) to rotate when the threaded guide (51) revolves.

8. The energy-saving urea production system according to claim 7, characterized in that: The transmission assembly further comprises a guide rod (52), the guide rod (52) being arranged in the condenser tube (2) and extending in the axial direction of the condenser tube (2), and the scraper ring (4) being slidably connected to the guide rod (52).

9. The energy-saving urea production system according to claim 8, characterized in that: A mounting plate (131) is provided in the water outlet chamber (13), the mounting plate (131) being fixedly connected to the second partition plate (15), one end of the threaded guide member (51) being rotatably mounted on the mounting plate (131), and one end of the guide rod (52) being fixedly mounted on the mounting plate (131).

10. The energy-saving urea production system according to claim 9, characterized in that: The gear mechanism comprises a transmission gear ring (53) and a transmission gear (54); the plurality of condenser tubes (2) form a plurality of distribution circles from the inside out; the transmission gear ring (53) is arranged with a plurality of gears from the inside out; the plurality of transmission gear rings (53) and the plurality of distribution circles correspond to each other; the transmission gear ring (53) is fixed on the housing (1); the transmission gear (54) is arranged at the other end of the threaded guide (51) and meshes with the adjacent transmission gear ring (53).

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