Gas purifying and cooling device

Abstract

The gas purifying and cooling device comprises a tower and an air cooler, the tower comprises a tower barrel, a plurality of sections of cooling tube bundles are arranged in the tower, a distributor is arranged above each section of tube bundle, a plurality of spray heads are arranged above the distributor, the spray heads are evenly distributed along the same circumference, and the spray heads are connected with a urine inlet; a condensate buffer cavity and a steam buffer cavity are respectively arranged outside the tower barrel, the cooling tube bundle consists of a plurality of heat exchange tubes, a horizontal tube section at the lower end of each heat exchange tube penetrates through the side wall of the tower barrel and extends into the condensate buffer cavity, and a horizontal tube section at the upper end of each heat exchange tube penetrates through the side wall of the tower barrel and extends into the steam buffer cavity; the distributor is provided with a conical collector along the periphery of the barrel, a material distribution disc is arranged in the middle of the distributor, and a conical collector is arranged in the middle of the distribution disc. The device has the beneficial effects that erosion corrosion of the heat exchange tubes is prevented, the service life of the heat exchange tubes is prolonged, the blockage problem of the heat exchange tube bundle is reduced, and the shutdown frequency is reduced.

Description

Technical Field

[0001] The invention belongs to the field of chemical equipment, and in particular relates to a gas purification and cooling device in melamine production. Background Art

[0002] At present, in the production of melamine, the washing tower is one of the most important key equipment. Its process is to wash the process circulating gas with urea to remove impurities such as solid particles in the process circulating gas, and at the same time use one or more sections of heat exchange tubes with equal spacing in the tower to form a heat exchange tube bundle to reduce the gas temperature. The specific process is: the urea solution is mixed with the process gas through the nozzle, and passes through the heat exchange tube bundle for heat exchange and cooling, so that the process circulating gas is cooled to complete the purification and cooling process, and then enters the next gas-liquid separation process. The steam condensate in the heat exchange tube is heated and vaporized and enters the air cooler. After condensation, it returns to the condensation buffer chamber for recycling.

[0003] In actual operation, it was found that the urine inlet was unevenly distributed, which affected the purification effect. The urine was sprayed directly onto the straight section of the tube bundle through the nozzle. After a period of time, the straight section was blocked and corroded. The condensed gas from the air cooler was occasionally accompanied by steam when it returned to the condensate buffer chamber, which affected the condensation effect. The vertical sections of each heat exchange tube in the heat exchange tube bundle are distributed along multiple layers of concentric circles. The upper and lower ends of the vertical sections of each heat exchange tube are transitioned to the horizontal sections through curved sections, and the bending radius of the curved sections at the upper and lower parts of the same layer of heat exchange tubes is the same, the bending radius of the curved sections of the outer layer of heat exchange tubes is smaller, and the bending radius of the curved sections of the inner layer of heat exchange tubes is larger. As a result, the spacing between the curved sections of each layer is small, which can easily cause scaling and blockage between the curved sections at the lower end. Summary of the invention

[0004] The purpose of the present invention is to provide a set of purification cooling device, set a distributor, solve the blockage and corrosion problems caused by uneven urine distribution, and extend the design operation cycle. Set a liquid separator at the outlet of the air cooler to solve the problem of steam entrainment.

[0005] The technical solution of the present invention is as follows: a gas purification and cooling device, comprising: a tower 1, an air cooler 15, wherein the tower 1 comprises a tower cylinder 17, the upper part of which is provided with a scrubbing gas inlet 18, the lower end of which is provided with a liquid phase outlet 19, the upper part of the cylinder is provided with a urine inlet 3, a plurality of cooling tube bundles 8 are arranged inside the tower 1, a distributor 5 is arranged above each tube bundle 8, a plurality of nozzles 4 are arranged above the distributor 5, the plurality of nozzles 4 are evenly distributed along the same circumference, and the nozzles 4 are connected to the urine inlet 3; the tower cylinder 17 is respectively provided with The condensate buffer chamber 12 and the steam buffer chamber 7 are welded to the tower 1 to form a closed cavity. The cooling tube bundle 8 is composed of a plurality of heat exchange tubes. The lower horizontal tube section of each heat exchange tube passes through the side wall of the tower cylinder 17 and extends to the inside of the condensate buffer chamber 12. The upper horizontal tube section of each heat exchange tube passes through the side wall of the tower cylinder 17 and extends to the inside of the steam buffer chamber 7. The distributor 5 is a conical collector along the cylinder, with a material distribution plate 20 in the middle, and a conical collector 21 in the middle of the distribution plate 20.

[0006] Furthermore, the steam outlet 6 on the steam buffer chamber 7 is connected to the air cooler inlet 14, the air cooler outlet 16 is connected to the separator tank 11, the liquid phase outlet of the separator tank 11 is connected to the condensate inlet 13 on the condensate buffer chamber 12 through a process pipeline, and the gas phase outlet 10 of the separator tank 11 is connected to the air cooler inlet 14 through a process pipeline.

[0007] Furthermore, the liquid separator 11 is arranged at the outlet of the air cooler 15, the lower part of the liquid separator 11 is provided with a condensate outlet, and the upper part of the liquid separator 11 is provided with a steam outlet.

[0008] Furthermore, the heat exchange tubes in the cooling tube bundle 8, except for the outermost heat exchange tubes, are all asymmetric heat exchange tubes, the bending radii of the bent tube sections at the bottom of all heat exchange tubes are the same, and the diameters of the heat exchange tubes are the same.

[0009] Furthermore, the diameter of the distribution plate 20 of the distributor 5 corresponds to the distribution range of the vertical tube sections of the heat exchange tubes of the tube bundle 8 below the distribution plate 20, and the multiple distribution holes on the distribution plate 20 are respectively coaxially arranged with the vertical tube sections of the heat exchange tubes below it.

[0010] Furthermore, a heat tracing pipe 9 is provided on the outer wall of the tower body 1 between the condensate buffer chamber 12 and the steam buffer chamber 7 .

[0011] Furthermore, the nozzle 4 is connected to the urine inlet 3 through the outer ring tube 2 of the cylinder.

[0012] Furthermore, the diameter of the distribution holes on the distribution plate 20 is φ20-φ25 mm.

[0013] The beneficial effects of the present invention are as follows: the arrangement of a nozzle and a distributor above each tube bundle facilitates the distribution of urine, prevents erosion and corrosion of the heat exchange tube, prolongs the service life of the heat exchange tube, reduces the blockage problem of the heat exchange tube bundle, reduces the number of parking times, and effectively prevents urine from forming a short circuit, thereby enhancing the cooling effect. The air cooler forms a closed-loop condensation system with the condensation buffer chamber and the steam buffer chamber outside the washing tower to ensure full liquefaction, avoid steam entrainment, and prevent condensate from being lost. No liquid replenishment is required during the entire production cycle, thereby saving energy. The use of asymmetric heat exchange tubes increases the spacing between the lower curved tube sections, thereby reducing the scaling problem of the lower curved tube sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the present invention;

[0015] Figure 2 It is a schematic diagram of the distribution plate of the distributor in the present invention;

[0016] Figure 3 for Figure 2 A top view of

[0017] Figure 4 It is a top view schematic diagram of the nozzle and the outer ring tube of the barrel in the present invention;

[0018] Figure 5 Schematic diagram of asymmetric heat exchange tubes.

[0019] In the figure: 1. tower; 2. outer ring pipe of the cylinder; 3. urine inlet; 4. nozzle; 5. distributor; 6. steam outlet; 7. steam buffer chamber; 8. tube bundle; 9. outer coil; 10. steam outlet; 11. liquid separator; 12. condensate buffer chamber; 13. condensate inlet; 14. air cooler inlet; 15. air cooler; 16. air cooler outlet; 17. tower cylinder; 18. scrubbing gas inlet; 19. liquid phase outlet; 20. distributor distribution plate; 21. cone collector; 22. cone shell. DETAILED DESCRIPTION

[0020] In order to explain the technical solution of this patent more clearly and completely, the technical solution will be described below in conjunction with specific embodiments and drawings.

[0021] See also Figure 1 A gas purification and cooling device includes a tower 1, an air cooler 15, and a liquid separator 11, wherein the tower 1 includes a tower barrel 17, a washing gas inlet 18 is provided at the upper part of the tower barrel 17, a liquid phase outlet 19 is provided at the lower end, and a urine inlet 3 is provided at the upper part of the tower barrel 17. A plurality of cooling tube bundles 8 are provided inside the tower 1, and a condensate buffer chamber 12 and a steam buffer chamber 7 are provided outside the tower 1, respectively, and each buffer chamber is welded to the tower barrel 17 to form a closed cavity.

[0022] See also Figure 5 The cooling tube bundle 8 is composed of a plurality of heat exchange tubes, the number of which is determined according to the required heat exchange amount, and each heat exchange tube has a vertical tube section, the upper and lower ends of which are respectively transitioned to the horizontal tube section through the curved tube section. The vertical tube sections of each heat exchange tube constituting the cooling tube bundle 8 are distributed along the multi-layer concentric circles centered on the axis of the tower 1, the lower horizontal tube section of each heat exchange tube passes through the side wall of the tower barrel 17 and extends to the inside of the condensate buffer chamber 12, and the upper horizontal tube section of each heat exchange tube passes through the side wall of the tower barrel 17 and extends to the inside of the steam buffer chamber 7. A distributor 5 is arranged above each cooling tube bundle 8, and the distributor 5 mainly includes a distribution plate 20, a conical collector 21 and a conical shell 22, and a plurality of distribution holes are opened on the distribution plate 20. A conical collector 21 is arranged in the middle of the distribution plate 20, and the diameter of the conical collector 21 is determined by the circular un-pipeline area formed in the middle of the tube bundle 8, and the size of the circular un-pipeline area is determined by the number, diameter, spacing and other factors of the heat exchange tubes. The distribution plate 20 is connected to the cone shell 22, and the cone shell 22 is welded to the tower cylinder 17. A plurality of nozzles 4 are evenly arranged in the tower cylinder 17 above the distributor 5. Figure 4 The nozzles 4 are evenly distributed along the same circumference, and the nozzles 4 are connected to the same outer ring tube 2 provided outside the tower cylinder 17, and the outer ring tube 2 is connected to the total inlet 3 of the washing liquid. The tower cylinder 17 is provided with a condensate buffer chamber 12 and a steam buffer chamber 7, respectively. The steam buffer chamber 7 is provided with a steam outlet 6, which is connected to the air cooler inlet 14. The air cooler outlet 16 is connected to the liquid separator 11. The liquid phase outlet of the liquid separator 11 is connected to the condensate inlet 13 on the condensate buffer chamber 12 through a process pipeline, and the gas phase outlet 10 of the liquid separator 11 is connected to the air cooler inlet 14 through a process pipeline.

[0023] One air cooler 15 corresponds to one or more cooling tube bundles 8, and can realize heat exchange of one or more tube bundles 8. In this embodiment, there are 4 cooling tube bundles 8 and 2 air coolers 15, and every 2 cooling tube bundles 8 correspond to one air cooler 15. The liquid separator 11 is small in size and can be directly set on the pipeline. Each air cooler 15 is equipped with a liquid separator 11.

[0024] The heat exchange tubes in the cooling tube bundle 8 described in this embodiment, except for the outermost heat exchange tubes, are all asymmetric heat exchange tubes. The asymmetric heat exchange tubes refer to the heat exchange tubes having different bending radii at the upper and lower bending sections, forming an asymmetric shape. The bending radii of the lower bending sections of all heat exchange tubes are the same. The diameters of the above heat exchange tubes are the same. Figure 5 The lower end of the asymmetric heat exchange tube bundle has the same bending radius of the heat exchange tubes, which increases the length of the vertical tube section, improves the heat exchange effect, and makes the vertical tube section less prone to scaling. At the same time, the spacing between the lower curved tube sections of the heat exchange tubes is also increased, which can also reduce the scaling problem of the lower curved tube sections.

[0025] The diameter of the distribution plate 20 of the distributor 5 described in this embodiment corresponds to the distribution range of the vertical pipe sections of the heat exchange tubes of the tube bundle 8 below the distribution plate 20, and the multiple distribution holes on the distribution plate 20 are respectively coaxially arranged with the vertical pipe sections of the heat exchange tubes below it.

[0026] In this embodiment, distribution holes with different diameters of φ20-φ25 mm are formed on the distribution plate 20, and the distribution hole closest to the center of the tower 1 has the smallest diameter.

[0027] The condensate buffer chamber 12 and the steam buffer chamber 7 described in this embodiment are respectively welded to the tower cylinder 17 to form a closed cavity for storing condensate or steam and playing a certain buffering role.

[0028] See also Figure 5 In this embodiment, the distance between the outer wall of the condensate buffer chamber 12 and the steam buffer chamber 7 and the outer wall of the tower barrel 17 is set to L, generally L = 180 ~ 240mm, the width of the condensate buffer chamber 12 and the steam buffer chamber 7 extends outward from the horizontal pipe section of the innermost layer of heat exchange tubes and the horizontal pipe section of the outermost layer of heat exchange tubes by a distance H, and H is generally about 150mm.

[0029] The outer wall of the tower cylinder 17 described in this embodiment is provided with a heating coil 9 between the condensate buffer chamber 12 and the steam buffer chamber 7 to heat the cylinder.

[0030] In this embodiment, a heating coil 9 is arranged on the outer wall of the tower barrel 17 between the upper end of the condensate buffer chamber 12 and the lower end of the steam buffer chamber 7. The specification of the heating coil 9 is DN25, and one or more groups can be arranged and coiled on the above-mentioned position of the tower barrel 17 at the same time.

[0031] The working process of the cooling purification device described in this embodiment is as follows: urine is evenly distributed on the outer ring tube 2 of the cylinder through the urine inlet 3 outside the tower 1, and then sprayed on the distributor 5 through the nozzle 4. The scrubbing gas enters from the scrubbing gas inlet 18 of the upper cylinder of the tower 1, merges with the urine coming from the nozzle 4 on the upper part of the cylinder, and then flows downward, passes through the distribution holes on the distribution plate 20 on the distributor 5, see Figure 2 and Figure 3, fully contacting with the tube bundle 8, exchanging heat, and completing the cooling process. Urine enters the tower 1 from the top nozzle 4, washes the scrubbing gas for the fourth time, then the urine goes downward, continues downward after heat exchange, and washes the scrubbing gas for the third time together with the urine entering the tower 1 from the second nozzle 4, then the urine goes downward, continues downward after heat exchange, and washes the scrubbing gas for the second time together with the urine entering the tower 1 from the third nozzle 4, then the urine goes downward, continues downward after heat exchange, and washes the scrubbing gas for the first time together with the urine entering the tower 1 from the bottom nozzle 4, and finally all the urine is discharged from the tower 1 from the liquid phase outlet 19. The condensate enters the heat exchange tube from the condensate buffer chamber 12, exchanges heat with the material mixed with solid particles in the tower 1, and then enters the air cooler 15 through the steam buffer chamber 7 and the air cooler inlet 14, and then enters the separator tank 11 from the air cooler outlet 16. The condensate comes out of the separator tank 11 and is transported to the condensate buffer chamber 12 through the process pipeline.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Other equivalent changes made using the patent concept of the present invention should all fall within the patent protection scope of the present invention.

Claims

1. A gas purification and cooling device, comprising: A tower (1), an air cooler (15), wherein the tower (1) comprises a tower cylinder (17), the upper part of which is provided with a scrubbing gas inlet (18), the lower end of which is provided with a liquid phase outlet (19), and the upper part of the cylinder is provided with a urine inlet (3), characterized in that: A plurality of cooling tube bundles (8) are arranged inside the tower (1), a distributor (5) is arranged above each tube bundle (8), a plurality of nozzles (4) are arranged above the distributor (5), the plurality of nozzles (4) are evenly distributed along the same circumference, and the nozzles (4) are connected to the urine inlet (3); A condensate buffer chamber (12) and a steam buffer chamber (7) are respectively arranged outside the tower barrel (17), and each buffer chamber is welded to the tower (1) to form a closed chamber. The cooling tube bundle (8) is composed of a plurality of heat exchange tubes, and the lower horizontal tube section of each heat exchange tube passes through the side wall of the tower barrel (17) and extends to the inside of the condensate buffer chamber (12), and the upper horizontal tube section of each heat exchange tube passes through the side wall of the tower barrel (17) and extends to the inside of the steam buffer chamber (7); The distributor (5) is a conical collector along the periphery of the cylinder, a material distribution plate (20) is arranged in the middle, and a conical collector (21) is arranged in the middle of the distribution plate (20).

2. A gas purification and cooling device according to claim 1, characterized in that: The steam outlet (6) on the steam buffer chamber (7) is connected to the air cooler inlet (14), the air cooler outlet (16) is connected to the separator tank (11), the liquid phase outlet of the separator tank (11) is connected to the condensate inlet (13) on the condensate buffer chamber (12) through a process pipeline, and the gas phase outlet (10) of the separator tank (11) is connected to the air cooler inlet (14) through a process pipeline.

3. A gas purification and cooling device according to claim 1, characterized in that: The liquid separator (11) is arranged at the outlet of the air cooler (15), and a condensate outlet is arranged at the lower part of the liquid separator (11), and a steam outlet is arranged at the upper part.

4. A gas purification device according to claim 1, characterized in that: The heat exchange tubes in the cooling tube bundle (8), except for the outermost heat exchange tubes, are all asymmetric heat exchange tubes, the bending radii of the bent tube sections at the bottom of all the heat exchange tubes are the same, and the diameters of the heat exchange tubes are the same.

5. A gas purification device according to claim 1, characterized in that: The diameter of the distribution plate (20) of the distributor (5) corresponds to the distribution range of the vertical pipe sections of the heat exchange tubes of the tube bundle (8) below the distribution plate (20), and the multiple distribution holes on the distribution plate (20) are respectively coaxially arranged with the vertical pipe sections of the heat exchange tubes below it.

6. A gas purification device according to claim 1, characterized in that: A heat tracing pipe (9) is arranged on the outer wall of the tower cylinder (1) between the condensate buffer chamber (12) and the steam buffer chamber (7).

7. A gas purification device according to claim 1, characterized in that: The spray head (4) is connected to the urine inlet (3) through the outer ring tube (2) of the cylinder.

8. A gas purification device according to claim 5, characterized in that: The diameter of the distribution holes on the distribution plate (20) is φ20-φ25 mm.

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