SO3 recovery system and use method thereof

Abstract

The invention relates to the technical field of sulfuric acid preparation, in particular to an SO3 recovery system and a using method thereof.The gas outlet of an acid mist collecting device is connected with the gas inlet of a first SO3 absorption tower, the gas outlet of the first SO3 absorption tower is connected with the gas inlet of a drying tower, the gas outlet of the drying tower is connected with the input end of a negative pressure fan, and the input end of the negative pressure fan is connected with the output end of a second SO3 absorption tower; the output end of the negative pressure fan is connected with a gas inlet of the conversion device, a gas outlet of the conversion device is connected with a gas inlet of the second SO3 absorption tower, a gas outlet of the second SO3 absorption tower is connected with a gas inlet of the tail gas desulfurization device, and a gas outlet of the tail gas desulfurization device is connected with the chimney; liquid outlets of the first SO3 absorption tower and the second SO3 absorption tower are connected with the circulating tank. The two SO3 absorption towers are arranged, and an acid mist collecting system and an SO2 conversion system are combined, so that the acid mist recovery rate is increased, and the environmental pollution caused by acid mist emission is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sulfuric acid preparation, in particular to a SO3 recovery system and a use method thereof. BACKGROUND

[0002] In chemical production, oleum is an important chemical raw material, which is widely used in the production process of dye, pharmaceutical, explosive and other industries. However, in the loading process of oleum, due to its strong volatility, SO3-containing acid mist is easily generated.

[0003] SO3 is a gas with strong corrosion, if directly discharged into the atmosphere, it will cause serious harm to the environment. It combines with moisture in the air to form sulfuric acid mist, which not only corrodes the surrounding equipment and buildings, but also leads to the formation of acid rain, destroys the ecological balance, and poses a great threat to the growth of plants and animals and human health. At the same time, the direct emission of SO3 is also a waste of resources, which reduces the economy of production. In order to solve the problem of SO3 volatilization in the loading process of oleum, some SO3 recovery devices have appeared in the prior art. However, these devices often have the problem of low recovery efficiency, a large amount of SO3 cannot be effectively recovered, and part of the acid mist is still discharged into the atmosphere. In addition, the existing recovery system has a relatively simple structure, lacks deep treatment of the gas, and the tail gas after recovery treatment may still contain a certain amount of SO3 and other harmful gases, which is difficult to meet the increasingly strict environmental protection standards. In addition, the stability and reliability of part of the recovery system are poor. In the long-term operation process, equipment blockage, corrosion and other problems are easy to occur, which affects the normal operation of the system, increases the maintenance cost and downtime. Moreover, the existing recovery system usually cannot realize effective recycling of the absorption liquid, causing waste of the absorbent and increasing the operation cost. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a SO3 recovery system and a use method thereof.

[0005] To achieve the above purpose, the technical scheme of the present application is as follows:

[0006] A SO3 recovery system, comprising an acid mist collecting device, a first SO3 absorption tower, a drying tower, a negative pressure fan, a conversion device, a second SO3 absorption tower, a tail gas desulfurization device, a chimney, a circulating tank and a solution pump; the upper part of the first SO3 absorption tower and the second SO3 absorption tower are each provided with an air outlet and a liquid inlet, and the lower part of each is provided with an air inlet and a liquid outlet; the acid mist collecting device is arranged at a fuming acid loading point, the air outlet of the acid mist collecting device is connected to the air inlet of the first SO3 absorption tower, the air outlet of the first SO3 absorption tower is connected to the air inlet of the drying tower, the air inlet of the drying tower is also connected to an SO2 flue gas pipeline, the air outlet of the drying tower is connected to the input end of the negative pressure fan, the output end of the negative pressure fan is connected to the air inlet of the conversion device, the air outlet of the conversion device is connected to the air inlet of the second SO3 absorption tower, the air outlet of the second SO3 absorption tower is connected to the air inlet of the tail gas desulfurization device, and the air outlet of the tail gas desulfurization device is connected to the chimney; the input end of the solution pump is connected to the circulating tank, and the output end of the solution pump is provided with a first branch and a second branch, the first branch is connected to the liquid inlet of the first SO3 absorption tower, and the second branch is connected to the liquid inlet of the second SO3 absorption tower; the liquid outlets of the first SO3 absorption tower and the second SO3 absorption tower are both connected to the circulating tank.

[0007] Further, a mixed acid device is further included, which is arranged inside the circulating tank, the output end of the solution pump is further provided with a third branch, the third branch is connected to the liquid inlet of the mixed acid device, the liquid inlet of the mixed acid device is further connected to a water pipe, and the liquid outlet of the mixed acid device is in communication with the inside of the circulating tank.

[0008] Further, the drying tower is filled with 3% concentrated sulfuric acid, the bottom of the drying tower is provided with an acid concentration sensor, and the liquid outlet of the drying tower is connected to the circulating tank.

[0009] Further, the first SO3 absorption tower and the second SO3 absorption tower are each internally provided with a spraying layer and a filler layer, and the spraying layer is located above the filler layer.

[0010] Further, the circulating tank is filled with 98% concentrated sulfuric acid, and the circulating tank is provided with a stirring device.

[0011] The application further includes the following technical solutions:

[0012] A use method of the above SO3 recovery system, comprising the following steps:

[0013] S1, start the negative pressure fan and the solution pump, the acid mist generated by the smoking acid enters the acid mist collecting device and the first SO3 absorption tower in turn under the action of the negative pressure fan, the acid mist flows from bottom to top in the first SO3 absorption tower, and the 98% concentrated sulfuric acid in the circulating tank enters the first SO3 absorption tower and the second SO3 absorption tower from top to bottom under the action of the solution pump; the SO3 in the acid mist is absorbed by the 98% concentrated sulfuric acid in the first SO3 absorption tower, and the generated first absorption liquid is discharged into the circulating tank through the liquid outlet of the first SO3 absorption tower;

[0014] S2, the acid mist after the first SO3 absorption tower enters the drying tower to remove water together with the SO2 flue gas, and then enters the conversion device to produce SO3;

[0015] S3, the SO3 produced by the conversion device flows from bottom to top into the second SO3 absorption tower under the action of the negative pressure fan, and is absorbed by the 98% concentrated sulfuric acid flowing from top to bottom in the second SO3 absorption tower, and the generated second absorption liquid is discharged into the circulating tank through the liquid outlet of the second SO3 absorption tower; the waste gas generated by the second SO3 absorption tower is desulfurized by the tail gas desulfurization device and then discharged through the chimney.

[0016] Compared with the prior art, the beneficial effects of the present application are:

[0017] The present application provides a SO3 recovery system and a use method thereof, by setting two SO3 absorption towers, combining the acid mist collecting system and the SO2 conversion system, the acid mist enters the acid mist collecting device and the first SO3 absorption tower through the negative pressure in the SO2 conversion system, which improves the recovery rate of the acid mist, and the acid mist after absorption can enter the second SO3 absorption tower again after passing through the drying tower and the conversion device with the SO2 flue gas, which improves the recovery rate of SO3 and effectively reduces the pollution of acid mist emission to the environment. At the same time, the system is provided with a mixed acid device, which supplements water into the circulating tank to dilute sulfuric acid, so that the concentration of sulfuric acid in the circulating tank is maintained at 98%, which ensures the stable operation of the system. The drying tower is filled with 93% concentrated sulfuric acid, and the acid concentration sensor arranged at the bottom of the drying tower is linked with the liquid supplementing device, when the acid concentration is lower than 90%, the concentrated sulfuric acid is automatically supplemented, and the dilute acid is discharged into the circulating tank for diluting sulfuric acid, which not only realizes the stable control of the concentration of sulfuric acid in the drying tower, but also reasonably utilizes the dilute acid, further optimizes the treatment and utilization of sulfuric acid in the system, and improves the resource utilization rate and the reliability of the system operation. BRIEF DESCRIPTION OF DRAWINGS

[0018] The embodiments of the present application are further described below with reference to the accompanying drawings, in which:

[0019] Figure 1 The structure schematic diagram of the SO3 recovery system embodiment is shown;

[0020] Fig. 1 is an acid mist collecting device, 2 is a first SO3 absorption tower, 3 is a drying tower, 4 is a negative pressure fan, 5 is a conversion device, 6 is a second SO3 absorption tower, 7 is a tail gas desulfurization device, 8 is a chimney, 9 is a circulating tank, 10 is a solution pump, and 11 is a mixed acid device. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with specific examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application.

[0022] Reference is made to the accompanying drawings Figure 1 A SO3 recovery system includes an acid mist collecting device 1, a first SO3 absorption tower 2, a drying tower 3, a negative pressure fan 4, a conversion device 5, a second SO3 absorption tower 6, a tail gas desulfurization device 7, a chimney 8, a circulating tank 9, and a solution pump 10. The upper part of the first SO3 absorption tower 2 and the second SO3 absorption tower 6 are each provided with a gas outlet and a liquid inlet, and the lower part of each is provided with a gas inlet and a liquid outlet. The acid mist collecting device 1 is arranged at a point where the acid smoke is loaded, the gas outlet of the acid mist collecting device 1 is connected to the gas inlet of the first SO3 absorption tower 2, the gas outlet of the first SO3 absorption tower 2 is connected to the gas inlet of the drying tower 3, the gas inlet of the drying tower 3 is also connected to a SO2 flue gas pipeline, the gas outlet of the drying tower 3 is connected to the input end of the negative pressure fan 4, the output end of the negative pressure fan 4 is connected to the gas inlet of the conversion device 5, the gas outlet of the conversion device 5 is connected to the gas inlet of the second SO3 absorption tower 6, the gas outlet of the second SO3 absorption tower 6 is connected to the gas inlet of the tail gas desulfurization device 7, and the gas outlet of the tail gas desulfurization device 7 is connected to the chimney 8. The input end of the solution pump 10 is connected to the circulating tank 9, the output end of the solution pump 10 is provided with a first branch and a second branch, the first branch is connected to the liquid inlet of the first SO3 absorption tower 2, the second branch is connected to the liquid inlet of the second SO3 absorption tower 2, and the liquid outlets of the first SO3 absorption tower 2 and the second SO3 absorption tower 6 are both connected to the circulating tank 9.

[0023] In an embodiment of the present application, a mixed acid device 11 is further included, which is arranged inside the circulating tank 9, the output end of the solution pump 10 is further provided with a third branch, the third branch is connected to the liquid inlet of the mixed acid device 11, the liquid inlet of the mixed acid device 11 is further connected to a water pipe, the liquid outlet of the mixed acid device 11 is in communication with the inside of the circulating tank 9, and water is supplemented into the circulating tank 9 through the mixed acid device, which is used to dilute the sulfuric acid in the circulating tank 9, so that the concentration of the sulfuric acid in the circulating tank 9 is maintained at 98%.

[0024] In one embodiment of the present application, the drying tower 3 is filled with 93% concentrated sulfuric acid, the bottom of the drying tower 3 is provided with an acid concentration sensor, and the liquid outlet of the drying tower 3 is connected to the circulating tank 9; the acid concentration sensor is linked to the liquid supplementing device, and when the acid concentration is lower than 90%, concentrated sulfuric acid is automatically supplemented, and the dilute acid is discharged from the liquid outlet of the drying tower 3 into the circulating tank 9 for diluting the sulfuric acid in the circulating tank 9, so that the concentration of the sulfuric acid in the circulating tank 9 is maintained at 98%.

[0025] In one embodiment of the present application, the first SO3 absorption tower 2 and the second SO3 absorption tower 6 are both internally provided with a spraying layer and a packing layer, and the spraying layer is located above the packing layer.

[0026] In one embodiment of the present application, the circulating tank 9 is filled with 98% concentrated sulfuric acid, and the circulating tank 9 is provided with a stirring device.

[0027] A use method of the above-mentioned SO3 recovery system, comprising the following steps:

[0028] S1, start the negative pressure fan 4 and the solution pump 10, the acid mist generated by the fuming acid is sequentially introduced into the acid mist collecting device 1 and the first SO3 absorption tower 2 under the action of the negative pressure fan 4, the acid mist flows from bottom to top in the first SO3 absorption tower 2, and the 98% concentrated sulfuric acid in the circulating tank 9 flows from top to bottom in the first SO3 absorption tower and the second SO3 absorption tower under the action of the solution pump 10; the SO3 in the acid mist is absorbed by the 98% concentrated sulfuric acid in the first SO3 absorption tower, and the generated first absorption liquid is discharged into the circulating tank 9 through the liquid outlet of the first SO3 absorption tower;

[0029] S2, the acid mist after passing through the first SO3 absorption tower enters the drying tower 3 to remove water together with the SO2 flue gas, and then enters the conversion device 5 to produce SO3;

[0030] S3, the SO3 produced by the conversion device 5 flows from bottom to top in the second SO3 absorption tower under the action of the negative pressure fan 4, is absorbed by the 98% concentrated sulfuric acid flowing from top to bottom in the second SO3 absorption tower, and the generated second absorption liquid is discharged into the circulating tank 9 through the liquid outlet of the second SO3 absorption tower; the waste gas generated by the second SO3 absorption tower is desulfurized by the tail gas desulfurization device 7 and then discharged through the chimney 8.

[0031] The application provides a SO3 recovery system and a use method thereof, which combines an acid mist collecting system and an SO2 conversion system by arranging two SO3 absorption towers, and the acid mist enters the acid mist collecting device and the first SO3 absorption tower through the negative pressure in the SO2 conversion system, so that the recovery rate of the acid mist is improved, and the acid mist of the absorbed SO3 can enter the second SO3 absorption tower again after the SO2 flue gas passes through a drying tower and a conversion device, so that the recovery rate of the SO3 is improved, and the pollution of the acid mist emission to the environment is effectively reduced. Meanwhile, the system is provided with a mixed acid device, water is supplemented into a circulating tank to dilute sulfuric acid, so that the concentration of the sulfuric acid in the circulating tank is maintained at 98%, and the stable operation of the system is ensured. The drying tower is filled with 93% concentrated sulfuric acid, and an acid concentration sensor arranged at the bottom of the drying tower is linked with a liquid supplementing device, when the acid concentration is lower than 90%, the concentrated sulfuric acid is automatically supplemented, and the dilute acid is discharged into the circulating tank for diluting the sulfuric acid, so that the stable control of the concentration of the sulfuric acid in the drying tower is realized, the dilute acid can be reasonably utilized, the treatment and utilization of the sulfuric acid by the system are further optimized, and the resource utilization rate and the reliability of the system operation are improved.

[0032] The above describes some example embodiments of the application, and it can be understood that the above embodiments are only used for explaining the application, and do not constitute a limitation on the protection scope of the application. The features in these embodiments can be recombined in a suitable manner, and the schemes obtained thereby are still within the protection scope required by the application. Based on the above embodiments, all other embodiments obtained by those skilled in the art without creative labor, i.e. all modifications, equivalent replacements and improvements, etc. made within the spirit and principles of the application, are within the protection scope required by the application.

Claims

1. A SO3 recovery system characterized by, The application relates to a sulfuric acid production device, which comprises an acid mist collecting device (1), a first SO3 absorption tower (2), a drying tower (3), a negative pressure fan (4), a conversion device (5), a second SO3 absorption tower (6), a tail gas desulfurization device (7), a chimney (8), a circulating tank (9) and a solution pump (10); the upper parts of the first SO3 absorption tower (2) and the second SO3 absorption tower (6) are provided with gas outlets and liquid inlets, and the lower parts are provided with gas inlets and liquid outlets; the acid mist collecting device (1) is arranged at a sulfuric acid loading point, the gas outlet of the acid mist collecting device (1) is connected with the gas inlet of the first SO3 absorption tower (2), the gas outlet of the first SO3 absorption tower (2) is connected with the gas inlet of the drying tower (3), the gas inlet of the drying tower (3) is also connected with an SO2 flue gas pipeline, the gas outlet of the drying tower (3) is connected with the input end of the negative pressure fan (4), the output end of the negative pressure fan (4) is connected with the gas inlet of the conversion device (5), the gas outlet of the conversion device (5) is connected with the gas inlet of the second SO3 absorption tower (6), the gas outlet of the second SO3 absorption tower (6) is connected with the gas inlet of the tail gas desulfurization device (7), and the gas outlet of the tail gas desulfurization device (7) is connected with the chimney (8); the input end of the solution pump (10) is connected with the circulating tank (9), the output end of the solution pump (10) is provided with a first branch and a second branch, the first branch is connected with the liquid inlet of the first SO3 absorption tower (2), the second branch is connected with the liquid inlet of the second SO3 absorption tower (2), and the liquid outlets of the first SO3 absorption tower (2) and the second SO3 absorption tower (6) are connected with the circulating tank (9).

2. The SO3 recovery system of claim 1, wherein, The device further comprises a mixed acid device (11), the mixed acid device is arranged in the circulating tank (9), the output end of the solution pump (10) is further provided with a third branch, the third branch is connected with the liquid inlet of the mixed acid device (11), the liquid inlet of the mixed acid device (11) is further connected with a water pipe, and the liquid outlet of the mixed acid device (11) is in communication with the inside of the circulating tank (9).

3. The SO3 recovery system of claim 1, wherein, The drying tower (3) is filled with 93% concentrated sulfuric acid, the bottom of the drying tower (3) is provided with an acid concentration sensor, and the liquid outlet of the drying tower (3) is connected with the circulating tank (9).

4. The SO3 recovery system of claim 1, wherein, The first SO3 absorption tower (2) and the second SO3 absorption tower (6) are both internally provided with a spraying layer and a filler layer, and the spraying layer is arranged above the filler layer.

5. The SO3 recovery system of claim 1, wherein, The circulating tank (9) is filled with 98% concentrated sulfuric acid, and the circulating tank (9) is provided with a stirring device.

6. A method of using the SO3 recovery system of claims 1-5, characterized in that, The device comprises the following steps: S1, start the negative pressure fan (4) and solution pump (10), the acid mist generated by the generating agent enters the acid mist collecting device (1) and the first SO3 absorption tower (2) in turn under the action of the negative pressure fan (4), the acid mist flows from bottom to top in the first SO3 absorption tower (2), and the 98% concentrated sulfuric acid in the circulating tank (9) flows from top to bottom in the first SO3 absorption tower and the second SO3 absorption tower under the action of the solution pump (10); the SO3 in the acid mist is absorbed by the 98% concentrated sulfuric acid in the first SO3 absorption tower, and the generated first absorption liquid is discharged into the circulating tank (9) through the liquid outlet of the first SO3 absorption tower; S2, the acid mist after the first SO3 absorption tower enters the drying tower (3) to remove water together with the SO2 flue gas, and then enters the conversion device (5) to produce SO3; S3, the SO3 produced by the conversion device (5) flows from bottom to top in the second SO3 absorption tower under the action of the negative pressure fan (4), is absorbed by the 98% concentrated sulfuric acid flowing from top to bottom in the second SO3 absorption tower, and the generated second absorption liquid is discharged into the circulating tank (9) through the liquid outlet of the second SO3 absorption tower; the waste gas generated by the second SO3 absorption tower is desulfurized by the tail gas desulfurization device (7) and then discharged through the chimney (8).

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