Multistage oleum absorption tower and process for absorbing sulfur trioxide with oleum

Abstract

The application discloses a multi-stage fuming sulfuric acid absorption tower and a process method for absorbing sulfur trioxide by using the fuming sulfuric acid absorption tower. The multi-stage fuming sulfuric acid absorption tower comprises a primary absorption assembly and a secondary absorption assembly. The primary absorption assembly is provided with a first containing cavity. A first acid distributor is arranged in the first containing cavity and is arranged close to the upper wall surface of the first containing cavity and used for spraying acid liquid into the first containing cavity. The primary absorption assembly is provided with a flue gas inlet communicated with the first containing cavity. The secondary absorption assembly is arranged above the primary absorption assembly. The secondary absorption assembly is provided with a second containing cavity. The second containing cavity is communicated with the first containing cavity and used for receiving flue gas from the first containing cavity. A second acid distributor is arranged close to the upper wall surface of the second containing cavity and used for spraying acid liquid into the second containing cavity. The upper end of the secondary absorption assembly is provided with a flue gas outlet communicated with the second containing cavity. In this way, the sulfur trioxide absorption rate can be improved, and the product purity can be ensured.

Description

Technical Field

[0001] This invention relates to the field of chemical preparation technology, and in particular to a multi-stage fuming sulfuric acid absorption tower and a process for absorbing sulfur trioxide with fuming sulfuric acid. Background Technology

[0002] In the sulfuric acid production process, the fuming sulfuric acid absorption tower is mainly used to absorb sulfur trioxide in the flue gas after conversion to prepare fuming sulfuric acid. In the existing technology, the single tower absorption method is mostly used to absorb sulfur trioxide. The absorption is only carried out by one acid spraying, which is difficult to fully absorb sulfur trioxide in the flue gas. This not only leads to a low sulfur trioxide absorption rate, but also increases the burden of subsequent treatment due to the residual sulfur trioxide in the tail gas. At the same time, if a fuming sulfuric acid product with a qualified concentration is to be obtained, single tower absorption is more likely to be mixed with impurities, affecting the purity of the product. Summary of the Invention

[0003] The main objective of this invention is to propose a multi-stage fuming sulfuric acid absorption tower and a process for absorbing sulfur trioxide with fuming sulfuric acid, aiming to improve the problems of low absorption rate, low qualified rate of fuming sulfuric acid product concentration, and high impurity content in existing fuming sulfuric acid absorption towers.

[0004] To achieve the above objectives, the multi-stage fuming sulfuric acid absorption tower proposed in this invention comprises: A primary absorption assembly extends vertically and has a first accommodating cavity. A first acid separator is disposed within the first accommodating cavity. The first acid separator is disposed near the upper wall of the first accommodating cavity and is used to spray acid liquid into the first accommodating cavity. The primary absorption assembly has a flue gas inlet that communicates with the first accommodating cavity. A secondary absorption assembly is disposed above the primary absorption assembly and extends vertically. The secondary absorption assembly has a second receiving cavity that communicates with the first receiving cavity to receive flue gas from the first receiving cavity. A second acid separator is provided near the upper wall of the second receiving cavity for spraying acid liquid into the second receiving cavity. The secondary absorption assembly also has a flue gas outlet communicating with the second receiving cavity, located at the upper end of the secondary absorption assembly.

[0005] In one embodiment, the flue gas inlet is located on the horizontally upward sidewall of the primary absorption assembly and is positioned close to the lower wall surface of the first accommodating cavity.

[0006] In one embodiment, the secondary absorption assembly further includes a riser pipe, which is disposed on the lower wall of the second accommodating cavity and connected to the first accommodating cavity. The riser pipe is used to allow flue gas to enter the second accommodating cavity from the first accommodating cavity.

[0007] In one embodiment, the secondary absorption assembly further includes a liquid blocking section, which is spaced above the opening of the riser pipe and blocks the opening of the riser pipe.

[0008] In one embodiment, the multi-stage fuming sulfuric acid absorption tower further includes an acid-adding component, which includes two acid-adding structures. The two acid-adding structures are respectively arranged corresponding to the first-stage absorption component and the second-stage absorption component. Each acid-adding structure includes an upper acid section and a lower acid section arranged vertically and upwardly at intervals. The upper acid section is located above the lower acid section. The two upper acid sections are respectively connected to the first acid separator and the second acid separator for adding acid liquid to the first acid separator and the second acid separator respectively.

[0009] In one embodiment, the acid feeding section includes an acid feeding port, which is opened on the side wall of the primary absorption component or the secondary absorption component and is disposed near the upper wall surface of the first accommodating cavity or the second accommodating cavity. The acid feeding port is connected to the first acid separator or the second acid separator. The lower acid section includes a lower acid port, which is opened on the side wall of the primary absorption component or the secondary absorption component and is located near the lower wall surface of the first accommodating cavity or the second accommodating cavity.

[0010] In one embodiment, the primary absorption component is made of Q345R steel; and / or, The secondary absorption component is made of high-silicon stainless steel.

[0011] In one embodiment, the primary absorption assembly includes an outer shell and an inner liner. The outer shell is fitted over the outer side of the inner liner and is fixedly connected to the secondary absorption assembly. The inner liner encloses and forms the first accommodating cavity.

[0012] In one embodiment, the material of the lining includes acid-resistant brick.

[0013] This invention also proposes a process for absorbing sulfur trioxide with fuming sulfuric acid. Based on the above-mentioned multi-stage fuming sulfuric acid absorption tower, the process for absorbing sulfur trioxide with fuming sulfuric acid includes: Flue gas is introduced into the first receiving cavity from the flue gas inlet so that it comes into direct contact with the acid sprayed by the first acid separator. The acid sprayed by the first acid separator performs primary absorption of sulfur trioxide in the flue gas to obtain primary treated flue gas. The flue gas after primary treatment is introduced from the first accommodating cavity into the second accommodating cavity so as to come into direct contact with the acid sprayed by the second acid separator. The acid sprayed by the second acid separator performs secondary absorption of sulfur trioxide in the flue gas after primary treatment to obtain flue gas after secondary treatment. The flue gas after secondary treatment is discharged from the flue gas outlet of the multi-stage fuming sulfuric acid absorption tower.

[0014] In the technical solution of this invention, during the production of sulfur trioxide from flue gas, flue gas is first introduced into the first accommodating cavity of the primary absorption assembly. At this time, the flue gas enters the first accommodating cavity through the flue gas inlet. Simultaneously, the first acid separator operates, spraying acid liquid into the first accommodating cavity. The acid liquid drips downwards, causing the flue gas to move upwards within the first accommodating cavity, ensuring sufficient countercurrent contact with the acid liquid. This allows the primary absorption assembly to achieve the first absorption of sulfur trioxide from the flue gas within the first accommodating cavity. The flue gas that has completed the first absorption can then... The flue gas continues to move upwards, entering the second cavity from the first cavity. At this time, the second acid separator in the second cavity sprays acid into the second cavity, and the acid in the second cavity drips downwards. The flue gas that has completed the first absorption can continue to move upwards in the second cavity to fully countercurrently contact the acid in the second cavity, thereby achieving the second absorption of sulfur trioxide in the flue gas in the second cavity. The flue gas that has completed the second absorption continues to move upwards to be discharged from the flue gas outlet of the multi-stage fuming sulfuric acid absorption tower and enter the next process. This configuration, through the combined arrangement of the primary and secondary absorption components, enables the flue gas to undergo two sulfur trioxide absorption processes within independent physical spaces. Through multi-stage absorption, the sulfur trioxide absorption rate is increased while sulfuric acid production is reduced by 98%, ensuring that the exhaust gas meets emission standards. Furthermore, the acid solutions in the first and second accommodating chambers are independent of each other, further preventing mixing between the acid solutions in the first and second accommodating chambers and ensuring the purity of the product. This achieves a state of continuous gas phase and disconnected liquid phase between stages. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of an embodiment of the multi-stage fuming sulfuric acid absorption tower provided by the present invention; Figure 2 This is a schematic flow chart of an embodiment of the process for absorbing sulfur trioxide with fuming sulfuric acid provided by the present invention.

[0017] Explanation of icon numbers: 100. Multi-stage fuming sulfuric acid absorption tower; 1. Primary absorption assembly; 11. First acid separator; 12. Flue gas inlet; 2. Secondary absorption assembly; 21. Second acid separator; 22. Flue gas outlet; 23. Riser pipe; 24. Liquid blocking section; 3. Acid adding assembly; 31. Upper acid section; 32. Lower acid section.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0022] In the sulfuric acid production process, the fuming sulfuric acid absorption tower is mainly used to absorb sulfur trioxide in the flue gas after conversion to prepare fuming sulfuric acid. In the existing technology, the single tower absorption method is mostly used to absorb sulfur trioxide. The absorption is only carried out by one acid spraying, which is difficult to fully absorb sulfur trioxide in the flue gas. This not only leads to a low sulfur trioxide absorption rate, but also increases the burden of subsequent treatment due to the residual sulfur trioxide in the tail gas. At the same time, if a fuming sulfuric acid product with a qualified concentration is to be obtained, single tower absorption is more likely to be mixed with impurities, affecting the purity of the product.

[0023] This invention proposes a multi-stage fuming sulfuric acid absorption tower, which aims to improve the problems of low absorption rate, low qualified rate of fuming sulfuric acid product concentration, and high impurity content in existing fuming sulfuric acid absorption towers.

[0024] Please see Figure 1 In one embodiment of the present invention, the multi-stage fuming sulfuric acid absorption tower 100 includes a primary absorption assembly and a secondary absorption assembly 2. The primary absorption assembly 1 extends vertically and has a first receiving cavity. A first acid separator 11 is disposed within the first receiving cavity and is positioned near the upper wall of the first receiving cavity for spraying acid solution into the first receiving cavity. The primary absorption assembly 1 has a flue gas inlet 12 communicating with the first receiving cavity. The secondary absorption assembly 2 is disposed above the primary absorption assembly 1 and extends vertically. The secondary absorption assembly 2 has a second receiving cavity communicating with the first receiving cavity to receive flue gas from the first receiving cavity. A second acid separator 21 is disposed near the upper wall of the second receiving cavity for spraying acid solution into the second receiving cavity. The secondary absorption assembly 2 also has a flue gas outlet 22 communicating with the second receiving cavity and is located at the upper end of the secondary absorption assembly 2.

[0025] In the technical solution of this invention, during the production of sulfur trioxide from flue gas, flue gas is first introduced into the first accommodating cavity of the primary absorption assembly 1. At this time, the flue gas enters the first accommodating cavity through the flue gas inlet 12. Simultaneously, the first acid separator 11 operates, spraying acid liquid into the first accommodating cavity. The acid liquid drips downwards, causing the flue gas to move upwards within the first accommodating cavity, ensuring sufficient countercurrent contact with the acid liquid. This allows the primary absorption assembly 1 to achieve the first absorption of sulfur trioxide from the flue gas within the first accommodating cavity. The flue gas that has completed the first absorption can then... The flue gas can continue to move upward to enter the second cavity from the first cavity. At this time, the second acid separator 21 in the second cavity can spray acid into the second cavity. The acid in the second cavity also drips downward. The flue gas that has completed the first absorption can continue to move upward in the second cavity to fully countercurrent contact with the acid in the second cavity, thereby achieving the second absorption of sulfur trioxide in the flue gas in the second cavity. The flue gas that has completed the second absorption continues to move upward to be discharged from the flue gas outlet 22 of the multi-stage fuming sulfuric acid absorption tower 100 and enter the next process. This configuration, through the combined arrangement of the primary absorption component 1 and the secondary absorption component 2, enables the flue gas to achieve two sulfur trioxide absorption operations within independent physical spaces. Through multi-stage absorption, the sulfur trioxide absorption rate is improved while reducing sulfuric acid production by 98%, ensuring that the exhaust gas meets emission standards. Furthermore, the acid solutions in the first and second accommodating chambers are independent of each other, further preventing the mixing of acid solutions in the first and second accommodating chambers and ensuring the purity of the product. This achieves a state of continuous gas phase and disconnected liquid phase between stages.

[0026] It should be noted that, in this invention, in order to ensure the continuous gas phase and disconnected liquid phase communication between the primary absorption component 1 and the secondary absorption component 2, the first accommodating cavity and the second accommodating cavity are configured to be in a communication form that allows only gas to pass through.

[0027] It is understood that, in this invention, in order to further increase the contact area between the acid and the flue gas and ensure sufficient contact between the acid and the flue gas in the first and second accommodating cavities, the acid spray nozzles of the first acid separator 11 and the second acid separator 21 can be configured with a densely distributed fine pore structure. In this way, the acid sprayed by the first acid separator 11 and the second acid separator 21 can be dispersed into fine droplets by the milled pore structure, uniformly covering the cross-section of the first and second accommodating cavities, maximizing the contact area with the flue gas.

[0028] In one embodiment, to further enhance the contact reaction between flue gas and acid, the first and second accommodating cavities are further filled with a regular packing layer. The packing layer has multiple holes formed along the vertical direction. The arrangement of the multiple holes not only provides a channel for the rising flue gas, but also provides sufficient adhesion surface for the acid to form a stable liquid film. Furthermore, during the rising process of the flue gas, the packing layer can also cut and divert the rising flue gas, causing the flue gas to form a turbulent state in the accommodating cavity, which greatly prolongs the contact time between the flue gas and the acid.

[0029] Of course, to ensure that the flue gas discharged from the multi-stage fuming sulfuric acid absorption tower 100 through the flue gas outlet 22 meets emission requirements, in one embodiment of the present invention, a flue gas concentration monitoring probe is also provided at the flue gas outlet 22 of the secondary absorption component 2. The flue gas concentration monitoring probe is electrically connected to an external control system and can monitor the residual sulfur trioxide concentration in the discharged flue gas in real time. When the concentration is detected to exceed a preset threshold, the control system will automatically adjust the acid spray volume of the first acid separator 11 and the second acid separator 21, or adjust the flue gas inlet speed, to ensure that the finally discharged flue gas always meets the standards. At the same time, it can also dynamically optimize the absorption process parameters based on the monitoring data to achieve energy-saving and efficient operation.

[0030] It should also be noted that, since the flue gas enters the first accommodating cavity through the flue gas inlet 12 and then moves upward within the first accommodating cavity to contact the acid solution, in order to extend the movement path of the flue gas and thus extend the contact time between the flue gas and the acid solution, in one embodiment of the present invention, the flue gas inlet 12 is located on the horizontally upward sidewall of the primary absorption component 1, and is positioned close to the lower wall of the first accommodating cavity. With this configuration, after the flue gas enters from a position close to the lower wall of the first accommodating cavity, it needs to flow upward along the entire height of the first accommodating cavity to enter the secondary absorption component 2, maximizing the movement path of the flue gas within the first accommodating cavity, allowing for a longer contact reaction time between the flue gas and the falling acid solution, and further improving the primary absorption efficiency of sulfur trioxide.

[0031] Furthermore, since the secondary absorption component 2 is located above and connected to the primary absorption component 1, when the flue gas enters the second accommodating cavity from the first accommodating cavity, the flue gas is positioned close to the lower wall of the second accommodating cavity. At this time, the flue gas also needs to flow upward along the entire height of the second accommodating cavity before it can be discharged from the flue gas outlet 22. This further prolongs the contact time between the flue gas and the acid sprayed by the second acid separator 21, thereby enhancing the secondary absorption efficiency.

[0032] Understandably, to ensure sufficient contact time between the flue gas and the acid sprayed by the second acid separator 21 within the second accommodating cavity, in one embodiment of the present invention, the secondary absorption assembly 2 further includes a riser pipe 23. The riser pipe 23 is disposed on the lower wall of the second accommodating cavity and communicates with the first accommodating cavity. The riser pipe 23 is used to allow flue gas to enter the second accommodating cavity from the first accommodating cavity. This configuration... After the flue gas enters the riser pipe 23 from the first accommodating cavity, it is transported upwards along the riser pipe 23 to a position near the lower wall of the second accommodating cavity for release. This allows the flue gas inlet in the second accommodating cavity to be positioned close to its lower wall, meaning that if the flue gas needs to exit from the flue gas outlet 22 located at the upper end of the second accommodating cavity, the flue gas must flow through the entire second accommodating cavity, significantly extending the contact time between the flue gas and the acid sprayed by the second acid separator 21. Simultaneously, the riser pipe 23 prevents the acid in the first accommodating cavity from entering the second accommodating cavity due to liquid carried by the flue gas or splashing, further ensuring the liquid phase separation between the two accommodating cavities and maintaining the purity of the product.

[0033] Of course, when the riser pipe 23 is provided, in order to ensure a continuous gas phase and a disconnected liquid phase connection between the primary absorption component 1 and the secondary absorption component 2, in one embodiment of the present invention, the riser pipe 23 is bent downwards. Thus, in this embodiment, When the flue gas enters the riser pipe 23 from the first accommodating cavity, it flows along the bend in the pipe opening until it flows into the second accommodating cavity. Meanwhile, the acid dripping from the first accommodating cavity is blocked by the bend in the pipe opening and cannot enter the second accommodating cavity through the riser pipe 23. Furthermore, the acid dripping from the second accommodating cavity is also blocked by the side wall of the bend in the pipe opening and cannot flow into the first accommodating cavity. Structurally, this completely separates the liquid phase between the two accommodating cavities without affecting the smooth flow of flue gas, further enhancing the design advantages of continuous gas phase and separated liquid phase. Simultaneously, the bend in the pipe opening also guides the rising flue gas, allowing it to diffuse more evenly after entering the second accommodating cavity, preventing excessively high local flue gas concentrations from affecting absorption efficiency.

[0034] In another embodiment of the present invention, the secondary absorption assembly 2 further includes a liquid-blocking section 24, which is spaced above the opening of the riser pipe 23 and blocks the opening of the riser pipe 23. With this configuration, when the acid in the second accommodating cavity drips downwards, it is effectively blocked by the liquid-blocking section 24, preventing it from directly falling into the opening of the riser pipe 23 and flowing into the first accommodating cavity, thus physically cutting off the liquid flow path between the two accommodating cavities. Simultaneously, after the flue gas flows upwards from the opening of the riser pipe 23, it diffuses outwards under the obstruction of the liquid-blocking section 24, uniformly entering the second accommodating cavity and forming a more thorough countercurrent contact with the acid sprayed by the second acid separator 21, further enhancing the effect of secondary absorption.

[0035] It is understood that the present invention does not limit the specific structural form of the liquid blocking part 24. In one embodiment of the present invention, the liquid blocking part 24 can be configured as a circular baffle with a diameter larger than the diameter of the opening of the gas riser 23, and the edge of the circular baffle is bent downward to form a retaining edge, which can not only block the dripping acid liquid from entering the gas riser 23 in all directions, but also guide the flue gas to diffuse smoothly in all directions.

[0036] In another embodiment of the present invention, the liquid blocking part 24 can also be configured as a conical baffle with the tip of the conical baffle facing upward. In this way, when the acid in the second accommodating cavity drips downward, the dripping acid will slide down the conical surface of the conical baffle and will not accumulate above the opening of the riser pipe 23. At the same time, after the flue gas flows upward from the opening of the riser pipe 23, it will diffuse into the second accommodating cavity from between the conical baffle and the riser pipe 23, ensuring the smooth diffusion of the flue gas and improving the secondary absorption efficiency.

[0037] Furthermore, in this invention, since the first acid separator 11 and the second acid separator 21 continuously spray acid into the first and second accommodating cavities, in order to avoid the accumulation of acid in the first and second accommodating cavities and to ensure that the first acid separator 11 and the second acid separator 21 can continuously maintain the spraying of acid, in one embodiment of this invention, the multi-stage fuming sulfuric acid absorption tower 100 further includes an acid-adding component 3. The acid-adding component 3 includes two acid-adding structures, which are respectively arranged corresponding to the first-stage absorption component 1 and the second-stage absorption component 2. Each acid-adding structure includes an upper acid section 31 and a lower acid section 32 arranged vertically and upwardly. The upper acid section 31 is located above the lower acid section 32. The two upper acid sections 31 are respectively connected to the first acid separator 11 and the second acid separator 21 for adding acid to the first acid separator 11 and the second acid separator 21 respectively. With this configuration, when the first acid separator 11 and the second acid separator 21 need to spray acid into the first and second accommodating cavities respectively, the upper acid section 31 of the two acid-adding structures can supply acid to the first acid separator 11 and the second acid separator 21 respectively to maintain the normal operation of the acid spraying work of the first acid separator 11 and the second acid separator 21. Afterwards, the acid that has come into contact with the flue gas accumulates on the lower wall surface of the first and second accommodating cavities. At this time, the lower acid section 32 of the two acid-adding structures can respectively discharge the acid accumulated in the first and second accommodating cavities, thereby avoiding the continuous accumulation of acid in the first and second accommodating cavities, which would cause the liquid level to become too high and then backflow back into the first acid separator 11, the second acid separator 21, or the riser pipe 23, disrupting the liquid phase disconnection state of the two-stage absorption components.

[0038] Of course, the present invention does not limit the specific structural forms of the upper acid section 31 and the lower acid section 32. In one embodiment of the present invention, the upper acid section 31 includes an upper acid port, which is opened on the side wall of the primary absorption component 1 or the secondary absorption component 2 and is disposed near the upper wall surface of the first accommodating cavity or the second accommodating cavity. The upper acid port is connected to the first acid separator 11 or the second acid separator 21. The lower acid section 32 includes a lower acid port, which is opened on the side wall of the primary absorption component 1 or the secondary absorption component 2 and is disposed near the lower wall surface of the first accommodating cavity or the second accommodating cavity. With this configuration, the external acid delivery pipeline can directly supply fresh acid to the first acid separator 11 and the second acid separator 21 through the upper acid port. The supply path is short, which can quickly respond to the acid demand of the acid separator and maintain a stable spray flow rate. The acid solution, after fully reacting with sulfur trioxide, will converge at the bottom of the first and second accommodating cavities under gravity, and then be promptly discharged through the acid outlet located near the lower wall. This not only allows for precise control of the acid level in the first and second accommodating cavities, avoiding the risk of backflow caused by excessively high levels, but also facilitates the collection, testing, and subsequent processing of the reacted acid solution by staff.

[0039] In other embodiments of the present invention, the upper acid portion 31 and the lower acid portion 32 may be configured in other forms. In actual configuration, they can be selected according to the requirements, and the present invention does not limit them.

[0040] In a further embodiment of the present invention, a flow regulating valve and an acid concentration sensor may also be provided at the acid inlet. The flow regulating valve can accurately control the acid supply amount according to the working requirements of the first acid separator 11 and the second acid separator 21. The acid concentration sensor monitors the concentration of the supplied acid in real time. When the concentration is lower than the preset value, an alarm will be automatically triggered and the system will switch to the high-concentration acid supply channel to ensure that the acid entering the acid separator always maintains the optimal absorption concentration and steadily improves the absorption efficiency of sulfur trioxide.

[0041] Similarly, in a further embodiment of the present invention, a liquid level sensor and a drain valve can also be provided at the acid outlet. When the acid level in the first or second accommodating cavity reaches a preset upper limit, the liquid level sensor will open the drain valve at the acid outlet in conjunction with the liquid level. When the liquid level drops to a preset lower limit, the drain valve will automatically close, thereby realizing automated and precise control of the acid level, reducing manual operation and avoiding abnormal liquid level affecting equipment operation.

[0042] Furthermore, it should be noted that, in order to ensure the service life of the primary absorption component 1 in this invention, in some embodiments, the material of the primary absorption component 1 includes Q345R steel. With this setting, Q345R steel has excellent corrosion resistance and mechanical strength, and can withstand the long-term corrosion of fuming sulfuric acid and sulfur trioxide. At the same time, this material also has good structural strength, and can withstand the flue gas pressure and acid gravity load inside the first accommodating cavity, effectively slowing down the aging and damage rate of the equipment and extending the overall service life.

[0043] Similarly, to ensure the service life of the secondary absorption component 2, in some embodiments, the secondary absorption component 2 is made of high-silicon stainless steel. This high-silicon stainless steel contains a large amount of silicon, which can quickly form a dense and stable silicon oxide protective film in an acidic environment. This protective film can effectively block further corrosion from fuming sulfuric acid and residual sulfur trioxide, maintaining the structural integrity of the secondary absorption component 2 even under long-term continuous operation. Simultaneously, high-silicon stainless steel also possesses excellent high-temperature resistance, adapting to the continuous high temperatures generated inside the second accommodating cavity due to the sulfur trioxide dissolution reaction, preventing cracking and deformation caused by thermal expansion and contraction, further ensuring the long-term stable operation of the secondary absorption component 2, and reducing equipment maintenance costs and replacement frequency.

[0044] It should also be noted that, in this invention, since the secondary absorption component 2 is located above the primary absorption component 1, and the primary absorption component 1 provides support for the secondary absorption component 2, in order to ensure the stability of the support provided by the primary absorption component 1 to the secondary absorption component 2, in one embodiment of this invention, the primary absorption component 1 includes an outer shell and an inner liner. The outer shell is fitted over the outer side of the inner liner and is fixedly connected to the secondary absorption component 2. The inner liner encloses and forms the first accommodating cavity. With this configuration, the outer shell can serve as a support structure for the secondary absorption component 2, supporting it vertically and providing stable support. Simultaneously, the inner liner encloses and forms the first accommodating cavity, providing contact space for the flue gas and acid, ensuring the normal operation of sulfur trioxide absorption within the first accommodating cavity.

[0045] In the above embodiments, to extend the service life of the primary absorption component 1 and reduce the rate of acid corrosion of the lining, in a further embodiment of the present invention, the lining material includes acid-resistant brick material. This arrangement provides the acid-resistant brick material with good corrosion resistance. It can maintain structural stability in the environment of long-term contact with fuming sulfuric acid, and will not be damaged or fall off due to acid corrosion. It effectively prevents the acid from directly contacting the outer shell, avoiding corrosion and damage to the outer shell, thereby greatly improving the overall service life of the primary absorption component 1.

[0046] Moreover, acid-resistant bricks also have excellent high-temperature resistance, and can withstand the heat released when sulfur trioxide reacts with sulfuric acid. They will not crack or break due to temperature changes, thus further ensuring the service life of the primary absorption component 1.

[0047] This invention also proposes a process for absorbing sulfur trioxide with fuming sulfuric acid; please refer to [link to relevant documentation]. Figure 2 This process is based on the aforementioned multi-stage fuming sulfuric acid absorption tower 100, and the process for absorbing sulfur trioxide with fuming sulfuric acid includes: S10. The flue gas is introduced into the first accommodating cavity from the flue gas inlet 12 so as to directly contact the acid sprayed by the first acid separator 11. The acid sprayed by the first acid separator 11 performs primary absorption of sulfur trioxide in the flue gas to obtain primary treated flue gas. Understandably, after the flue gas is introduced into the first accommodating cavity through the flue gas inlet 12, the flue gas will move upward in the first accommodating cavity. At this time, the first acid separator 11 sprays acid liquid, and the acid liquid drips downward under the action of gravity. The flue gas and the acid liquid move in opposite directions. In this way, the acid liquid can fully contact the flue gas in the opposite direction, thereby achieving primary absorption of sulfur trioxide in the flue gas, with an absorption efficiency of up to 50%.

[0048] S20. The flue gas after primary treatment is introduced from the first accommodating cavity into the second accommodating cavity so as to directly contact the acid sprayed by the second acid separator 21. The acid sprayed by the second acid separator 21 performs secondary absorption of sulfur trioxide in the flue gas after primary treatment to obtain flue gas after secondary treatment. It is understandable that when the flue gas after primary treatment enters the second accommodating cavity from the first accommodating cavity, the flue gas moves upward, while the acid sprayed by the second acid separator 21 in the second accommodating cavity drips downward, so as to move in the opposite direction to the flue gas after primary treatment, thereby making full contact with the flue gas in the opposite direction to achieve secondary absorption of sulfur trioxide in the flue gas, with an absorption efficiency of up to 20%.

[0049] S30. The flue gas after secondary treatment is discharged from the flue gas outlet 22 into the multi-stage fuming sulfuric acid absorption tower 100.

[0050] Through multi-stage absorption, the flue gas can meet the emission standards. Therefore, the flue gas after secondary treatment continues to move upward to be discharged from the multi-stage fuming sulfuric acid absorption tower 100 through the flue gas outlet 22 and enter the next process.

[0051] In the technical solution of the present invention, firstly, flue gas is introduced into the first accommodating cavity through the flue gas inlet 12. The flue gas will move upward in the first accommodating cavity. At this time, the first acid separator 11 sprays acid liquid, and the acid liquid drips downward under the action of gravity. The flue gas and the acid liquid move in opposite directions. In this way, the acid liquid can fully contact the flue gas in the opposite direction, thereby realizing the primary absorption of sulfur trioxide in the flue gas. After the secondary absorption component 2 completes the primary absorption of the flue gas, the flue gas after primary treatment can enter the second accommodating cavity from the first accommodating cavity and continue to move upward in the second accommodating cavity. At this time, the acid liquid sprayed by the second acid separator 21 in the second accommodating cavity drips downward to move in the opposite direction to the flue gas after primary treatment, thereby making full contact with the flue gas in the opposite direction and realizing the secondary absorption of sulfur trioxide in the flue gas. After the secondary absorption component 2 completes the secondary absorption of the flue gas after primary treatment, the flue gas after secondary treatment can be discharged from the multi-stage fuming sulfuric acid absorption tower 100 through the flue gas outlet 22. This configuration, through the combined arrangement of the primary absorption component 1 and the secondary absorption component 2, enables the flue gas to undergo two sulfur trioxide absorption processes within independent physical spaces. Through multi-stage absorption, the sulfur trioxide absorption rate is increased while sulfuric acid production is reduced by 98%, ensuring that the exhaust gas meets emission standards. Furthermore, the acid solutions in the first and second accommodating chambers are independent of each other, further preventing mixing between the acid solutions in the first and second accommodating chambers and ensuring the purity of the product. This achieves a state of continuous gas phase and disconnected liquid phase between stages.

[0052] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A multi-stage fuming sulfuric acid absorption tower, characterized in that, include: A primary absorption assembly extends vertically and has a first accommodating cavity. A first acid separator is disposed within the first accommodating cavity. The first acid separator is disposed near the upper wall of the first accommodating cavity and is used to spray acid liquid into the first accommodating cavity. The primary absorption assembly has a flue gas inlet that communicates with the first accommodating cavity. A secondary absorption component is disposed above the primary absorption component and extends vertically. The secondary absorption component has a second receiving cavity that is connected to the first receiving cavity to receive flue gas from the first receiving cavity. A second acid separator is provided near the upper wall of the second receiving cavity for spraying acid liquid into the second receiving cavity. The secondary absorption component also has a flue gas outlet that is connected to the second receiving cavity and is located at the upper end of the secondary absorption component.

2. The multi-stage fuming sulfuric acid absorption tower as described in claim 1, characterized in that, The flue gas inlet is located on the horizontally upward side wall of the secondary absorption assembly, and is positioned close to the lower wall surface of the first accommodating cavity.

3. The multi-stage fuming sulfuric acid absorption tower as described in claim 1, characterized in that, The secondary absorption assembly further includes a riser pipe, which is disposed on the lower wall of the second accommodating cavity and connected to the first accommodating cavity. The riser pipe is used to allow flue gas to enter the second accommodating cavity from the first accommodating cavity.

4. The multi-stage fuming sulfuric acid absorption tower as described in claim 3, characterized in that, The secondary absorption assembly also includes a liquid blocking section, which is spaced above the opening of the riser pipe and blocks the opening of the riser pipe.

5. The multi-stage fuming sulfuric acid absorption tower as described in claim 1, characterized in that, The multi-stage fuming sulfuric acid absorption tower also includes an acid-adding component, which includes two acid-adding structures. The two acid-adding structures are respectively arranged corresponding to the first-stage absorption component and the second-stage absorption component. Each acid-adding structure includes an upper acid section and a lower acid section arranged vertically and upwardly. The upper acid section is located above the lower acid section. The two upper acid sections are respectively connected to the first acid distributor and the second acid distributor for adding acid to the first acid distributor and the second acid distributor respectively.

6. The multi-stage fuming sulfuric acid absorption tower as described in claim 5, characterized in that, The acid supply section includes an acid supply port, which is opened on the side wall of the primary absorption component or the secondary absorption component and is located near the upper wall of the first accommodating cavity or the second accommodating cavity. The acid supply port is connected to the first acid separator or the second acid separator. The lower acid section includes a lower acid port, which is opened on the side wall of the primary absorption component or the secondary absorption component and is located near the lower wall surface of the first accommodating cavity or the second accommodating cavity.

7. The multi-stage fuming sulfuric acid absorption tower as described in claim 1, characterized in that, The primary absorption component is made of Q345R steel; and / or, The secondary absorption component is made of high-silicon stainless steel.

8. The multi-stage fuming sulfuric acid absorption tower as described in claim 1, characterized in that, The primary absorption component includes an outer shell and an inner liner. The outer shell is fitted over the outer side of the inner liner and is fixedly connected to the secondary absorption component. The inner liner encloses and forms the first accommodating cavity.

9. The multi-stage fuming sulfuric acid absorption tower as described in claim 8, characterized in that, The material of the inner lining includes acid-resistant brick.

10. A process for absorbing sulfur trioxide with fuming sulfuric acid, characterized in that, Based on the multi-stage fuming sulfuric acid absorption tower as described in any one of claims 1 to 9, the process for absorbing sulfur trioxide with fuming sulfuric acid includes: Flue gas is introduced into the first accommodating cavity from the flue gas inlet so that it comes into direct contact with the acid sprayed by the first acid separator. The acid sprayed by the first acid separator performs primary absorption of sulfur trioxide in the flue gas to obtain primary treated flue gas. The flue gas after primary treatment is introduced from the first accommodating cavity into the second accommodating cavity so that it comes into direct contact with the acid sprayed by the second acid separator. The acid sprayed by the second acid separator performs secondary absorption of sulfur trioxide in the flue gas after primary treatment to obtain flue gas after secondary treatment. The flue gas after secondary treatment is discharged from the flue gas outlet of the multi-stage fuming sulfuric acid absorption tower.

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