Separation and concentration device for urea production

Abstract

The utility model relates to a separation and concentration device for urea production, which comprises: a spraying assembly, the spraying assembly comprises a top nozzle and a plurality of annular nozzles, the top nozzle is connected with a top spraying pipe, and the annular nozzles are arranged on annular spraying pipes; and the separation assembly comprises a plurality of blades distributed along the circumference, and the blades are fixed between the top ring plate and the bottom ring plate. According to the separation and concentration device for urea production, the scaling cleaning effect can be improved, the content of biuret is reduced, and the separation efficiency is improved.

Description

Technical Field

[0001] This disclosure generally relates to the field of chemical equipment, and more specifically, to a separation and concentration apparatus for urea production. Background Technology

[0002] In the urea production process, the concentration rate of urine directly affects the quality of urea. The urine concentrations obtained by the first and second stage evaporation separators in the urea production unit must reach 95% and 99.7% respectively before it can successfully enter the next stage for granulation.

[0003] However, the first and second stage evaporator separators often experience problems such as crystallization, scaling, or excessive biuret content during operation. Urea crystallization or scaling directly clogs the gas-liquid separation elements in the equipment, resulting in substandard urine concentration. Furthermore, cleaning scaling and crystallization significantly increases maintenance workload, prolongs downtime, and reduces production efficiency. The presence of biuret is detrimental to crop seed germination and causes discoloration of straw; when producing acetal plastics from urea, a biuret content of 0.3% or higher easily causes the plastic to yellow.

[0004] Chinese patent application CN117839235A discloses a urea evaporation and separation device, whose separator includes multiple flushing nozzles inserted at the top of the separator and a scraping mechanism disposed on the inner wall of the separator for online cleaning of crystallized scale and biuret. However, because the flushing nozzles are located at the top of the separator, the scale and biuret on the lower inner wall of the separator and the scraping mechanism are difficult to clean thoroughly, resulting in poor scale removal and high biuret content.

[0005] Therefore, how to provide a separation and concentration device that improves the scaling and cleaning effect, reduces the biuret content, and increases the separation efficiency is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0006] In view of this, the present disclosure provides a separation and concentration apparatus for urea production to improve scaling and cleaning effects, reduce biuret content and increase separation efficiency.

[0007] Specifically, this disclosure provides a separation and concentration device for urea production, comprising: a spray assembly including a top nozzle and a plurality of ring nozzles, the top nozzle being connected to a top spray pipe and the ring nozzles being arranged on the ring spray pipe; and a separation assembly including a plurality of blades distributed circumferentially, the blades being fixed between a top ring plate and a bottom ring plate.

[0008] Optionally, the separation and concentration device further includes a reflux assembly, which includes a first baffle and a second baffle arranged on the outer periphery of the blade, wherein the first baffle is in fluid communication with the downcomer through a notch.

[0009] Optionally, the annular nozzle is a flat jet nozzle, which is oriented toward the blade; the top nozzle is a conical nozzle, which is arranged vertically downwards.

[0010] Optionally, the separation and concentration device is generally conical, including a cone apex and a cone body, the cone apex being connected to the top ring plate and the cone body being connected to the bottom ring plate.

[0011] Optionally, the top nozzle is installed above the cone apex, and the annular spray pipe is fixed to the cone apex.

[0012] Optionally, the top nozzle and the cone apex are connected by a support rib.

[0013] Optionally, the reflux assembly further includes a liquid collection pipe, which is in fluid communication with the downcomer.

[0014] Optionally, an inspection port is provided on the top of the cone.

[0015] Optionally, a reinforcing ring is welded to the lower surface of the bottom ring plate.

[0016] Compared with the prior art, the separation and concentration apparatus for urea production provided in this disclosure has at least the following beneficial effects:

[0017] 1. By linking the cone-shaped nozzle with the jet nozzle, full-coverage spraying and rinsing of key components (blades, cone tip) is achieved, effectively preventing crystal adhesion. This design significantly reduces flow channel blockage caused by scaling, substantially reduces downtime maintenance frequency, extends equipment continuous operation cycle, and improves overall production efficiency.

[0018] 2. The shape, angle and spacing of the blades can be dynamically adjusted according to the process parameters of different evaporation stages (such as single-stage evaporation and two-stage evaporation). This flexibility allows the device to adapt to the separation requirements of different concentrations, temperatures and material characteristics, expanding the application range of the equipment while maintaining high-efficiency separation performance.

[0019] 3. The synergistic effect of the first and second baffles ensures that the condensate is evenly distributed within the device and rapidly guided to the collection system. This design avoids eccentric load problems caused by localized liquid accumulation, reduces mechanical stress damage to the equipment, and optimizes the gas-liquid separation path, enhancing separation uniformity and stability, and ensuring consistent product quality.

[0020] 4. By reducing crystallization and flow channel resistance, the energy consumption of equipment operation is reduced; the efficient separation process shortens the material residence time, inhibits the formation of by-products (such as biuret), and improves product purity. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of this disclosure, the embodiments of this disclosure will be further explained and described with reference to the following drawings. These drawings are only used to more conveniently and specifically describe the embodiments of this disclosure and are not intended to limit this disclosure. In the drawings:

[0022] Figure 1 This is a front cross-sectional view of a separation and concentration apparatus for urea production according to one embodiment of the present disclosure;

[0023] Figure 2 This is a top view of a separation and concentration apparatus for urea production according to one embodiment of the present disclosure;

[0024] Figure 3 yes Figure 1 A partially enlarged schematic diagram of square frame II;

[0025] Figure 4 yes Figure 1 A partially enlarged schematic diagram of box I in the middle;

[0026] Figure 5 This is a partially enlarged schematic diagram of a blade according to one embodiment of the present disclosure.

[0027] In the diagram: 1-Cone apex, 11-Inspection port; 2-Cone body; 3-Spray assembly, 31-Top nozzle, 32-Ring nozzle, 33-Top spray pipe, 34-Ring spray pipe; 4-Separation assembly, 41-Blade, 42-Top ring plate, 43-Bottom ring plate, 431-Reinforcing ring; 5-Recirculation assembly, 51-First baffle, 52-Second baffle, 53-Notch, 54-Downcomer, 55-Accumulation pipe, 551-Tear hole; 6-Supporting rib. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, specific embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. These embodiments are provided by way of example only. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the described embodiments of this disclosure, all other embodiments obtained by those skilled in the art without inventive effort are also within the scope of protection claimed by this disclosure.

[0029] In the description of this disclosure, it should be noted that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure 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 disclosure.

[0030] In the description of this disclosure, unless otherwise expressly specified and limited, the terms "set," "install," "connect," "link," "fix," etc., should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0031] One embodiment of this disclosure provides a separation and concentration apparatus for urea production. For example... Figure 1 As shown, the separation and concentration device is generally conical, comprising a cone apex 1 and a cone body 2. Both cone apex 1 and cone body 2 can be made of corrosion-resistant materials such as stainless steel, duplex stainless steel, titanium alloy, or nickel-based alloys (e.g., Hastelloy C-276). For example, in high-temperature and highly corrosive environments, using titanium alloys can significantly extend equipment life; while in cost-sensitive scenarios, duplex stainless steel (e.g., S32205) can be used to balance corrosion resistance and economy. Furthermore, the inner wall of the cone can be coated with a ceramic coating (e.g., alumina or silicon carbide coating) to further enhance wear resistance and anti-fouling properties. The connection between cone apex 1 and cone body 2 is not limited to welding; flange connections or bolt fastening can also be used for modular assembly and disassembly. For large-scale units, cone body 2 can be designed as a segmented structure connected by annular flanges to adapt to different production scale requirements.

[0032] The separation and concentration device also includes a spray assembly 3 and a separation assembly 4. For example... Figure 1 and Figure 2As shown, the separation assembly 4 includes multiple blades 41 distributed circumferentially, which are welded between the top ring plate 42 and the bottom ring plate 43. In an alternative embodiment, in addition to welding, the blades 41 can also be fixed between the top ring plate 42 and the bottom ring plate 43 by bolts, facilitating later replacement or angle adjustment. A reinforcing ring 431 is welded to the lower surface of the bottom ring plate 43 to enhance its strength. The blades 41 can be made of 316L stainless steel, titanium alloy, or carbon steel coated with polytetrafluoroethylene (PTFE) to reduce droplet adhesion. The surface of the blades 41 is polished to effectively reduce fluid resistance. Figure 5 As shown, the blades 41 are formed in an arc shape with a spiral tapering flow channel design. The gas-liquid mixture enters the blade area and changes direction multiple times within the spiral tapering flow channel. Droplets collide and coalesce due to inertial impact, flowing downwards along the blade surface. Depending on specific process requirements, parameters such as the number, height, spacing, helix angle, and arrangement of the blades 41 can be adjusted to meet the separation needs of different evaporation stages (single / two stages) and different materials. In alternative embodiments, the flow channel design of the blades 41 is not limited to an arc-shaped spiral tapering design; wavy, serrated, or segmented flow channels can also be used. For example, a wavy flow channel can enhance droplet collision efficiency by periodically changing the fluid direction; a segmented flow channel can be set with different inclination angles in different areas to adapt to dynamic velocity changes in the gas-liquid mixture. Furthermore, the arrangement of the blades 41 can be optimized to be staggered or concentric circles to increase the separation path length. For high-viscosity materials, the blade spacing can be reduced to 10-15 mm, and the surface can be polished to Ra≤0.4μm to further reduce resistance. In the two-stage evaporation section, the helix angle of blade 41 can be adjusted from 45° to 60° to match the requirements of separating urine with higher concentrations. Furthermore, the optimal radius of curvature and spacing of the blade flow channel can be determined through CFD (Computational Fluid Dynamics) simulation.

[0033] The spray assembly 3 includes a top nozzle 31 and several annular nozzles 32. The top nozzle 31 is connected to the top spray pipe 33, and the annular nozzles 32 are arranged on the annular spray pipe 34. Specifically, the annular nozzles 32 can be flat jet nozzles, oriented towards the blades 41. The liquid sprayed from the flat jet nozzles washes the blades 41 to prevent crystallization on the blade surface, and also provides kinetic energy to the internal medium, increasing the flow rate of the urine-liquid mixture and improving the separation effect. The top nozzle 31 is a conical nozzle, installed above the cone apex 1, with the conical nozzle arranged vertically downwards to wash the upper surface of the cone apex 1 and prevent crystallization on the upper surface of the cone apex 1. Preferably, atomizing nozzles made of wear-resistant and corrosion-resistant materials (such as Hastelloy) are used to ensure uniform droplet size. The top nozzle 31 is connected to the cone apex 1 by a supporting rib 6. One end of the supporting rib 6 is welded to the conical nozzle, and the other end is welded to the cone 2 to ensure stable operation of the conical nozzle. The annular spray pipe 34 is fixed to the cone apex 1 by a connector. In alternative embodiments, the top nozzle 31 and annular nozzle 32 of the spray assembly 3 can be designed in various ways. The top nozzle 31 can be a rotary nozzle or an ultrasonic atomizing nozzle, in addition to a conical nozzle. For example, a rotary nozzle forms a uniform fan-shaped spray through centrifugal force, covering a larger area; an ultrasonic atomizing nozzle can produce micron-sized droplets, enhancing the dissolution ability of fine crystals. The flat jet nozzle of the annular nozzle 32 can be replaced with a fan-shaped nozzle or a vortex nozzle, where the vortex nozzle enhances the scouring force through a swirling effect. In addition to Hastelloy, the nozzle material can also be silicon carbide or silicon nitride ceramics, which are particularly suitable for media containing solid particles. The arrangement of the spray pipes 33 and 34 can be further optimized: for example, the annular spray pipe 34 can adopt a double-layer or multi-layer annular layout, with each layer independently controlling the spray pressure to adapt to scaling areas of different heights. Furthermore, the top spray pipe 33 can integrate a temperature sensor and a flow meter, linked with a central control system to achieve real-time adjustment of spray parameters. For example, when an abnormal increase in surface temperature is detected on blade 41, the spray volume of the corresponding nozzle is automatically increased to prevent crystal formation.

[0034] Optionally, the separation and concentration device further includes a reflux assembly 5. The reflux assembly 5 includes a first baffle 51 and a second baffle 52 arranged around the outer periphery of the blade 41. The blade 41 is not welded to either the first baffle 51 or the second baffle 52. The first baffle 51 is in fluid communication with the downcomer 54 through a notch 53. A notch 53 is provided at the connection between the lower end of the first baffle 51 and the cone apex 1, allowing the condensate on the cone apex 1 to pass through the notch 53 and enter the downcomer 54. The second baffle 52 is located near the downcomer 54, and its function is to evenly distribute the condensate on the cone apex 1 around the circumference of the cone apex 1, preventing it from concentrating in one place and allowing the cone apex 1 to bear an eccentric load. The reflux assembly 5 also includes a collection pipe 55, with a tear hole 551 on its bottom plate, in fluid communication with the downcomer 54. The downcomer 54 and the collection pipe 55 are welded together by a stiffener 56. The tear hole 551 serves to drain the condensate. The liquid separated from the blades 41 and the cone tip 1 flows through the cone 2 into the downcomer 54 under gravity, then into the collection pipe 55. After overflowing from the collection pipe 55, it is collected as the original liquid for further separation. In an alternative embodiment, the first baffle 51 and the second baffle 52 can be made of fiberglass or plastic-lined steel to reduce weight and enhance corrosion resistance. The shape of the baffles can be optimized as arc-shaped or baffle type. For example, an arc-shaped baffle can guide the condensate to flow tangentially, reducing eddy current generation. In addition to a straight pipe structure, the downcomer 54 can also be designed as a spiral downcomer to accelerate liquid discharge using centrifugal force. The tear orifice 551 of the collection pipe 55 can be replaced with an adjustable throttle valve to control the discharge speed of the collected liquid by adjusting the opening. Furthermore, a filter screen (pore size ≤ 50 μm) can be added to the collection pipe 55 to intercept solid particles and prevent clogging of downstream equipment. For high-load conditions, the reflux assembly 5 can be configured with a two-stage collection pipe, with the first stage for coarse separation and the second stage for fine separation, further improving liquid purity. Under extreme conditions, the downcomer 54 can be connected to an external vacuum pump to assist in drainage through negative pressure, ensuring continuous system operation.

[0035] Optionally, an access port 11 is provided on the cone top 1 to facilitate maintenance and repair work. In alternative embodiments, the design of the access port 11 can be further optimized as a quick-opening manhole or a sight glass integrated structure. For example, a quick-opening manhole uses a hinge and snap-lock device, which can be opened within 5 minutes, significantly shortening maintenance time. The sight glass can be made of high-temperature resistant borosilicate glass and equipped with LED lighting and a camera to achieve real-time monitoring of the internal status. In addition, a self-cleaning device can be added to the cone top 1, such as arranging a rotating spray arm around the access port 11 to periodically and automatically flush the inner wall of the cone top. For areas prone to scaling, an electric heating element (such as an armored heating wire) can be embedded in the inner wall of the cone top 1 to dissolve the attached crystals through periodic heating. Another alternative is to use magnetic anti-scaling technology, installing a permanent magnet array on the outer wall of the cone top 1 to inhibit the formation of hard scale by changing the crystal morphology of the urine medium.

[0036] The working principle of this separation and concentration device is as follows: the liquid sprayed from the top nozzle 31 and the ring nozzle 32 washes and peels off the crystalline medium adhering to the surface of the cone. Simultaneously, when the gas carrying droplets enters the blade separator, the fluid undergoes multiple rapid flow direction changes within the specially designed blade bundle space. During these changes, due to inertial forces, the droplets collide continuously with the blades; at the same time, the fluid rotates within the special flow channel structure of the blades. As the droplet kinetic energy decreases, the radius of rotation decreases sharply. The droplets and mist agglomerate due to surface tension colliding with the blade surface, resulting in increased coalescence and separation from the gas, adsorbing and coalescing on the blade surface. The collected liquid, under its own gravity, flows perpendicularly to the gas along the special channels of the blade structure towards the downcomer for collection, and then is discharged into the collection pipe through the downcomer, thus achieving gas-liquid separation.

[0037] It should be understood that the accompanying drawings in the embodiments of this disclosure only relate to structures relevant to the embodiments of this disclosure, while other structures can be referenced to conventional designs. The devices and / or structures in the various embodiments provided in this disclosure can be combined, modified, and / or changed to form new technical solutions. Without inventive effort, these technical solutions should also be included within the scope of protection claimed in this disclosure.

[0038] It should be understood that the specific examples provided in the embodiments described herein are for the purpose of illustrating the embodiments of this disclosure in detail and are not intended to limit the scope of this disclosure. The embodiments in this disclosure can be practiced without these specific examples. In some embodiments, structures and / or techniques well known to those skilled in the art have not been shown in detail so as not to obscure the understanding of this disclosure.

[0039] While preferred embodiments of the present disclosure have been shown and described herein, it will be readily understood by those skilled in the art that these embodiments are provided by way of example only. Various variations, modifications, and substitutions will occur to those skilled in the art without departing from the present disclosure. It should be understood that various alternatives to the embodiments of the present disclosure described herein are optionally used to implement the present disclosure. The scope of the present disclosure is intended to be defined by the appended claims, and thereby covers apparatuses, structures, and their equivalents within the scope of those claims.

Claims

1. A separation and concentration device for urea production, characterized in that, include: The spray assembly (3) includes a top nozzle (31) and a plurality of ring nozzles (32). The top nozzle (31) is connected to the top spray pipe (33), and the ring nozzles (32) are arranged on the ring spray pipe (34). as well as The separation component (4) includes a plurality of blades (41) distributed along the circumference, the blades (41) being fixed between the top ring plate (42) and the bottom ring plate (43).

2. The separation and concentration apparatus for urea production according to claim 1, characterized in that, The separation and concentration device further includes a reflux assembly (5), which includes a first baffle (51) and a second baffle (52) arranged on the outer periphery of the blade (41), wherein the first baffle (51) is in fluid communication with the downcomer (54) through a notch (53).

3. The separation and concentration apparatus for urea production according to claim 1 or 2, characterized in that, The annular nozzle (32) is a flat jet nozzle, which is oriented toward the blade (41); and the top nozzle (31) is a conical nozzle, which is arranged vertically downwards.

4. The separation and concentration apparatus for urea production according to claim 1, characterized in that, The separation and concentration device is generally conical, including a cone top (1) and a cone body (2), wherein the cone top (1) is connected to the top ring plate (42) and the cone body (2) is connected to the bottom ring plate (43).

5. The separation and concentration apparatus for urea production according to claim 4, characterized in that, The top nozzle (31) is installed above the cone top (1), and the annular spray pipe (34) is fixed on the cone top (1).

6. The separation and concentration apparatus for urea production according to claim 5, characterized in that, The top nozzle (31) is connected to the cone top (1) by a supporting rib plate (6).

7. The separation and concentration apparatus for urea production according to claim 2, characterized in that, The reflux assembly (5) further includes a liquid collection pipe (55), and the liquid collection pipe (55) is in fluid communication with the downcomer (54).

8. The separation and concentration apparatus for urea production according to claim 4, characterized in that, An inspection port (11) is provided on the top of the cone (1).

9. The separation and concentration apparatus for urea production according to claim 1, characterized in that, A reinforcing ring (431) is welded to the lower surface of the bottom ring plate (43).

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