Phthalic anhydride tail gas absorption spray tower

Abstract

The utility model discloses a phthalic anhydride tail gas absorption spray tower, which comprises a cylindrical tower body and a tail gas delivery pipe arranged in the middle of the tower body, a spherical filler area, a spray head, a demisting device and a tail gas outlet pipeline are sequentially arranged above the tail gas delivery pipe, a spray pump is arranged outside the tower body, a tail gas dispersion device is connected onto the tail gas delivery pipeline, and the spray head is connected onto the tail gas dispersion device. The tail gas dispersing device is composed of an annular main pipeline and a supporting plate, a plurality of air outlet holes are formed in the lower surface of the annular main pipeline, air outlet pipes are connected to the air outlet holes, and the air outlet pipes are sleeved with liquid blocking covers. According to the phthalic anhydride tail gas absorption spray tower disclosed by the utility model, the phthalic anhydride tail gas can be quickly and uniformly distributed in the spray tower through the tail gas dispersing device.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical equipment, in particular to a phthalic anhydride tail gas absorption spray tower. Background Art

[0002] In the industrial production of phthalic anhydride prepared by catalytic oxidation of o-xylene, the tail gas mainly contains phthalic anhydride and maleic anhydride, and a spray head is needed to hydrolyze phthalic anhydride and maleic anhydride, and the obtained phthalic acid and maleic acid are absorbed by water. In the prior art, the inlet to the tail gas spray tower is a horizontal pipeline, and the tail gas enters the spray tower from the middle of the spray tower through the suction of the induced draft fan. First, due to the concentration of the tail gas inlet, the dispersion of the tail gas in the spray tower is not ideal, resulting in inconsistent tail gas concentration on the same cross section in the spray tower, affecting the spray absorption effect. Often when the expected effect of tail gas absorption is achieved, a higher spray tower needs to be provided. Secondly, the solubility of phthalic acid in water is low at 7g / L (25°C). The tail gas pipeline is arranged horizontally, and the tail gas inlet cross section is vertical, resulting in the hydrolysis of phthalic anhydride in the tail gas when some water droplets fall at the inlet, and the generated phthalic acid accumulates at the tail gas inlet. After working for a long time, the accumulation of phthalic acid increases, affecting the entry of tail gas. Utility Model Content

[0003] In view of this, the utility model provides a phthalic anhydride tail gas absorption spray tower.

[0004] The technical solution adopted by the utility model to solve its technical problems is:

[0005] A phthalic anhydride tail gas absorption spray tower comprises a cylindrical tower body, a tail gas delivery pipe arranged in the middle of the tower body, a spherical filler area, a spray head, a demisting device and a tail gas outlet pipeline are arranged in sequence above the tail gas delivery pipe, a spray pump is arranged outside the tower body, a tail gas delivery pipeline is connected with a tail gas dispersion device, the tail gas dispersion device is composed of an annular main pipeline and a support plate, a plurality of air outlet holes are arranged on the lower surface of the annular main pipeline, the air outlet holes are connected with the air outlet pipe, and the air outlet pipe is sleeved with a liquid blocking cover.

[0006] Furthermore, the annular main pipeline is in the shape of a ring, and the outer diameter D of the ring is 圆环 The inner diameter D of the spray tower 塔体 The ratio is 1 / 3-2 / 3.

[0007] Furthermore, the annular main pipeline 21 is a square ring, and the side length L of the square ring is equal to the inner diameter D of the tower body of the spray tower. 塔体 The ratio is 2 / 5-3 / 5.

[0008] Furthermore, the support plate and the annular main pipe are not on the same plane, and the angle formed by the support plate and the plane where the annular main pipe is located is 45-60°.

[0009] Furthermore, the number of the support plates is 3-6 and they are evenly distributed along the annular main pipeline.

[0010] Furthermore, the outlet pipe takes the connection point between the tail gas inlet pipe and the annular main pipe as the base point, and the aperture of the outlet pipe away from the base point gradually increases, with an increase of 5%.

[0011] Furthermore, the air outlet pipe is composed of a first pipe and 2123, the first pipe is arranged perpendicular to the plane where the annular main pipe is located, and the angle between the first pipe and 2123 is an obtuse angle.

[0012] Furthermore, the included angle between the first tube and the second tube is an obtuse angle, and the obtuse angle is 120-150°.

[0013] Furthermore, the first tube and the air outlet are connected by threads, the first tube is provided with external threads, and the air outlet is provided with internal threads.

[0014] Furthermore, the first tube and the air outlet adopt a plug-in structure, and the upper end of the first tube and the lower end of the air outlet are interference fit.

[0015] The beneficial effects of the utility model are:

[0016] The phthalic anhydride tail gas absorption spray tower provided by the utility model comprises a cylindrical tower body, a tail gas delivery pipe arranged in the middle of the tower body, a spherical filling area, a spray head, a demisting device and a tail gas outlet pipeline are arranged in sequence above the tail gas delivery pipe, a spray pump is arranged outside the tower body, a tail gas dispersion device is connected to the tail gas delivery pipeline, the tail gas dispersion device is composed of an annular main pipeline and a support plate, a plurality of air outlet holes are arranged on the lower surface of the annular main pipeline, the air outlet holes are connected to the air outlet pipe, and a liquid blocking cover is arranged on the air outlet pipe. By adding a tail gas dispersion device to the tail gas input pipeline, the tail gas can be dispersed at multiple points after entering the spray tower, and the tail gas can be quickly and evenly dispersed in the spray tower, thereby increasing the absorption efficiency of the spray tower and the tail gas treatment effect. The setting of the liquid blocking cover can prevent the circulating spray liquid falling from the top from entering the air outlet pipe from the outlet of the air outlet pipe, causing the phthalic anhydride in the tail gas to be hydrolyzed and aggregated here, and the air outlet pipe is blocked due to long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 It is a structural schematic diagram of a phthalic anhydride tail gas absorption spray tower of the utility model;

[0019] Figure 2 for Figure 1 A bottom view of the tail gas dispersion device of the spray tower shown;

[0020] Figure 3 for Figure 2 A schematic diagram of the three-dimensional structure shown;

[0021] Figure 4 This is a schematic structural diagram of an air outlet pipe and a liquid retaining cover in another embodiment of the utility model;

[0022] In the figure: 100, spray tower, 1, exhaust gas conveying pipe, 2, exhaust gas dispersion device, 21, annular main pipeline, 211, air outlet, 212, air outlet pipe, 2121, liquid blocking cover, 2122, first pipe, 2123, second pipe, 22, support plate, 3, spherical filler area, 4, spray head, 5, demisting device, 6, exhaust gas outlet pipeline, 7, spray pump, 8, induced draft fan. DETAILED DESCRIPTION

[0023] Now the utility model is described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, which only illustrates the basic structure of the utility model in a schematic manner, so it only shows the components related to the utility model.

[0024] like Figure 1-3 As shown, the utility model provides a phthalic anhydride tail gas absorption spray tower 100, the tower body of the spray tower 100 is cylindrical, and is placed upright on a platform. The lower part is a circulating spray liquid storage area, and the middle part is provided with a tail gas dispersion device 2 arranged on the same plane as the tail gas conveying pipe 1, the tail gas conveying pipe 1 and the tail gas dispersion device 2 are connected by a pipeline, a spherical filler area 3 is arranged above the tail gas dispersion device 2, a spray head 4 is arranged above the spherical filler area 3, a demisting device 5 is arranged above the spray head 4, a tail gas outlet pipeline 6 is arranged at the top of the tower body, the tail gas outlet pipeline 6 is connected to the induced draft fan 8, and the induced draft fan 8 provides power and direction for the tail gas flow, a spray pump 7 is arranged outside the tower body of the spray tower 100, the inlet of the spray pump 7 is arranged in the spray liquid storage area, and the outlet is connected to the spray head 4 to provide circulating spray liquid to the spray head 4.

[0025] The tail gas dispersion device 2 is composed of an annular main pipeline 21 and a support plate 22. The annular main pipeline 21 is installed inside the spray tower through the support plate 22 and is concentric with the tower body. A plurality of air outlet holes 211 are provided on the lower surface of the annular main pipeline 21. The air outlet holes 211 are connected to air outlet pipes 212. The air outlet pipes 212 are evenly distributed on the lower surface of the annular main pipeline. A conical liquid blocking cover 2121 is provided on the outer side of the air outlet pipe 212. The liquid blocking cover 2121 can prevent the circulating spray liquid falling from above from entering the air outlet position of the air outlet pipe 212. During operation, phthalic anhydride tail gas enters from the tail gas delivery pipe 1 and is distributed through the annular main pipeline 21 and the air outlet pipe 212, so that the phthalic anhydride tail gas enters the spray tower 100 at multiple points on the horizontal cross section, which has a good dispersion effect. At the same time, the liquid blocking cover 2121 can prevent the circulating spray liquid from falling on the outer wall of the air outlet pipe 212, further reducing the accumulation of phthalic anhydride at the air outlet of the air outlet pipe 212.

[0026] In some embodiments, the support plate 22 and the annular main pipe 21 are not on the same plane, the angle formed by the support plate 22 and the plane where the annular main pipe 21 is located is 45-60°, and the number of support plates is 3-6 and evenly distributed.

[0027] In some embodiments, the annular main pipe 21 is annular, with an outer diameter D 圆环 The inner diameter D of the spray tower 100 塔体 The ratio is 1 / 3-2 / 3.

[0028] In some embodiments, the annular main pipeline 21 is a square ring, and the side length L is equal to the inner diameter D of the spray tower 100. 塔体 The ratio is 2 / 5-3 / 5.

[0029] The outlet pipe 212 takes the connection point between the exhaust inlet pipe 1 and the annular main pipe 21 as the base point, and the aperture of the outlet pipe 212 away from the base point gradually increases by 5%, and the maximum aperture of the outlet pipe 212 is not greater than the diameter of the annular main pipe 21. The increased aperture can make up for the smaller outflow due to the distance from the gas source, ensuring that the amount of gas flowing out in the horizontal cross-section direction is basically the same.

[0030] like Figure 4As shown, in some embodiments, the outlet pipe 212 is composed of a first pipe 2122 and a second pipe 2123, the first pipe 2122 and the plane where the annular main pipeline 21 are located are perpendicular, the angle formed between the second pipe 2123 and the first pipe 2122 is an obtuse angle, and a liquid shield is provided on the second pipe 2123. The outer diameter of the first pipe 2122 matches the aperture of the outlet hole 211, so that the first pipe 2122 can be installed in the outlet hole 211, and the second pipe 2123 is set to change the flow direction of the incoming tail gas by rotating the first pipe 2122, and adjust the distribution of the tail gas on the horizontal cross section without changing the annular main pipeline 21. The angle is an obtuse angle preferably of 120-150°. If the angle is too small, the water vapor in the tower body will condense at the outlet of the second pipe 2123, which is not easy to fall and contact with the tail gas, causing phthalic anhydride to be hydrolyzed here, and the hydrolysis product phthalic acid accumulates here, causing blockage due to long-term operation; if the angle is too large, the effect of regulating the outflow direction of the tail gas will be reduced.

[0031] The first tube 2122 and the air outlet 211 are connected by threads, that is, the first tube 2122 is provided with external threads, and the air outlet 211 is provided with internal threads. The first tube 2122 and the air outlet 211 can also adopt a plug-in structure, and the upper end of the first tube 2122 and the air outlet 211 are interference fit.

[0032] The material of the gas distribution device 2 is acid-corrosion-resistant material, preferably polypropylene, which is cheap, easy to process, light in weight, and convenient to install.

[0033] The technical solution disclosed in the utility model can allow the phthalic anhydride tail gas entering the spray tower 100 to be distributed at multiple positions on the same cross section by connecting the tail gas dispersion device at the outlet of the tail gas delivery pipe 1, avoiding concentration at one point, so that the phthalic anhydride tail gas in the spray tower 100 is evenly distributed, and the contact with the circulating spray liquid sprayed by the spray head 4 is more sufficient, thereby improving the absorption efficiency and absorption quality of the phthalic anhydride tail gas. By adding a tail gas dispersion device to the tail gas input pipeline, the tail gas can be dispersed at multiple points after entering the spray tower, allowing the tail gas to be quickly and evenly dispersed in the spray tower, increasing the absorption efficiency of the spray tower and the tail gas treatment effect. The setting of the liquid shield 2121 can prevent the circulating spray liquid falling from above from entering the outlet of the outlet pipe, causing the phthalic anhydride in the tail gas to be hydrolyzed and aggregated here, and the outlet pipe is blocked due to long-term use.

[0034] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without departing from the scope of the utility model through the above description. The technical scope of this utility model is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A phthalic anhydride tail gas absorption spray tower, comprising a cylindrical tower body, a tail gas delivery pipe arranged in the middle of the tower body, a spherical filler area, a spray head, a demisting device and a tail gas outlet pipeline are arranged in sequence above the tail gas delivery pipe, and a spray pump is arranged outside the tower body, characterized in that: The exhaust gas delivery pipeline is connected with an exhaust gas dispersion device, which is composed of an annular main pipeline and a support plate. A plurality of air outlet holes are arranged on the lower surface of the annular main pipeline, and an air outlet pipe is connected to the air outlet holes. A liquid blocking cover is provided on the air outlet pipe.

2. The phthalic anhydride tail gas absorption spray tower according to claim 1, characterized in that, The annular main pipeline is in the shape of a ring, and the outer diameter D of the ring 圆环 The inner diameter D of the spray tower 塔体 The ratio is 1 / 3-2 / 3.

3. The phthalic anhydride tail gas absorption spray tower according to claim 1, characterized in that, The annular main pipeline is a square ring, and the side length L of the square ring is equal to the inner diameter D of the tower body of the spray tower. 塔体 The ratio is 2 / 5-3 / 5.

4. The phthalic anhydride tail gas absorption spray tower according to claim 2, characterized in that, The support plate and the annular main pipe are not on the same plane, and the angle formed by the support plate and the plane where the annular main pipe is located is 45-60°.

5. The phthalic anhydride tail gas absorption spray tower according to claim 1, characterized in that, The number of the support plates is 3-6 and they are evenly distributed along the annular main pipeline.

6. The phthalic anhydride tail gas absorption spray tower according to claim 1, characterized in that, The outlet pipe takes the connection point between the tail gas inlet pipe and the annular main pipe as the base point, and the aperture of the outlet pipe away from the base point gradually increases, with an increase range of 5%.

7. The phthalic anhydride tail gas absorption spray tower according to claim 1, characterized in that: The air outlet pipe is composed of a first pipe and a second pipe. The first pipe is arranged perpendicular to the plane where the annular main pipe is located, and the angle between the first pipe and the second pipe is an obtuse angle.

8. The phthalic anhydride tail gas absorption spray tower according to claim 7, characterized in that, The obtuse angle is 120-150°.

9. The phthalic anhydride tail gas absorption spray tower according to claim 7, characterized in that: The first tube and the air outlet are connected by threads, the first tube is provided with external threads, and the air outlet is provided with internal threads.

10. The phthalic anhydride tail gas absorption spray tower according to claim 7, characterized in that: The first tube and the air outlet adopt a plug-in structure, and the upper end of the first tube and the lower end of the air outlet are interference fit.

Images