Sulfur trioxide gas impurity removal device

Abstract

The utility model relates to the field of electronic-grade sulfuric acid production equipment, in particular to a sulfur trioxide gas impurity removal device which is arranged at the rear end of a fuming sulfuric acid evaporator and comprises a cooling device and a defoaming device, and a gas inlet pipeline of the cooling device is connected with an outlet of the fuming sulfuric acid evaporator through an external pipeline. A gas outlet pipeline of the cooling device is connected with a feeding port of the defoaming device through a pipeline, a discharging port of the defoaming device is connected with follow-up equipment of a production line, gas sulfur trioxide firstly passes through the cooling device, the temperature of the gas sulfur trioxide is reduced to about 80 DEG C, then the gas sulfur trioxide is conveyed into the defoaming device, and the gas sulfur trioxide is discharged out of the production line. Acid mist in sulfur trioxide gas is removed in the defoaming device, so that the purity and the quality of sulfur trioxide are improved, meanwhile, damage to equipment caused by a high-temperature acid environment is avoided, and the service life of the device is effectively prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of electronic grade sulfuric acid production equipment, especially to a sulfur trioxide gas impurity removal device. BACKGROUND

[0002] Sulfur trioxide is the main material in the industrial preparation of sulfuric acid process, and the concentration and purity of sulfur trioxide have a direct impact on the quality and yield of sulfuric acid, so the monitoring and control of sulfur trioxide are crucial in the entire production process.

[0003] In traditional industrial production, liquid sulfur trioxide is mainly prepared by heating fuming sulfuric acid. This process is mainly carried out in a fuming sulfuric acid evaporator, and the free sulfur trioxide is released by heating. A small amount of water may be brought in during the evaporation process, which will react with sulfur trioxide to generate acid mist. Since liquid is more likely to dissolve impurities such as iron ions and nickel ions, the content of impurities such as iron ions and nickel ions entrained in the acid mist is usually several tens of times that of sulfur trioxide gas. The presence of these impurities will reduce the purity and quality of the final product.

[0004] In the industrial process, there are usually two methods for removing impurities from sulfur trioxide gas. The first method is to use natural cooling process to remove impurities by extending the connecting pipeline between the fuming sulfuric acid evaporator and the subsequent equipment. During the pipeline transportation of sulfur trioxide gas, small droplets containing metal impurities will deposit in the pipeline under the action of gravity, and the waste liquid in the pipeline will be discharged by the staff on a regular basis. However, this method not only increases the demand for production space and improves the cost of pipeline maintenance and repair for operators, but also makes it difficult to ensure the effect of impurity removal.

[0005] The second method is to directly set the impurity removal equipment at the rear end of the fuming sulfuric acid evaporator. Although this method is more direct, the temperature of sulfur trioxide gas evaporated from the evaporator is usually as high as 120℃ or even higher, which makes the impurity removal equipment exposed to high temperature and acidic environment for a long time, shortens its service life and increases the equipment maintenance cost.

[0006] Therefore, there is an urgent need for a new device that can remove impurities from sulfur trioxide gas evaporated from the evaporator. Not only can it effectively remove impurities from sulfur trioxide gas, but also can ensure the long-term stable operation of the equipment in high temperature environment, prolong the service life of the equipment, reduce the maintenance cost, and improve the efficiency and reliability of the entire production process. TECHNICAL FIELD

[0007] To solve the problems mentioned in the background art and overcome the above shortcomings, the utility model provides the following technical solutions:

[0008] The sulfur trioxide gas impurity removal device is arranged at the rear end of the oleum evaporator, and comprises a cooling device and a defoaming device, wherein the gas inlet pipeline of the cooling device is connected with the outlet of the oleum evaporator through an external pipeline, the gas outlet pipeline of the cooling device is connected with the feeding port of the defoaming device through a pipeline, and the discharging port of the defoaming device is connected with the subsequent equipment of the production line.

[0009] The main body of the cooling device is a tank body, and the tank body is provided with an air inlet and an air outlet at the top, respectively. In order to facilitate the connection with the oleum evaporator, a sulfur trioxide gas inlet pipeline and a gas outlet pipeline are arranged on the transverse direction of the tank body of the cooling device, respectively. The gas inlet pipeline is arranged close to the end of the oleum evaporator, and the gas outlet pipeline is arranged at the other end. A gas transmission plate with a jacket is arranged in the tank body, and the gas transmission plate is connected with the gas inlet pipeline and the gas outlet pipeline. Sulfur trioxide gas enters from the gas inlet pipeline and passes through the gas transmission plate. Air exchanges heat with sulfur trioxide gas outside the gas transmission plate.

[0010] Further, the air inlet is arranged close to the gas outlet pipeline, and the air outlet is arranged close to the gas inlet pipeline. In this way, the flowing direction of sulfur trioxide gas passing through the gas transmission plate is opposite to that of air outside the gas transmission plate, so that the temperature of sulfur trioxide gas at the gas outlet pipeline can be more accurately controlled, the temperature fluctuation at the gas outlet pipeline is reduced, and the safety of the system is improved.

[0011] Further, a fan is arranged at the air outlet, so as to facilitate the extraction of air used for heat exchange in the cooling device.

[0012] Further, the temperature of air sent from the air inlet is 40-45℃, and the temperature of air used for heat exchange should not be too low, so as to avoid the condensation of sulfur trioxide gas passing through the gas transmission plate and ensure that sulfur trioxide discharged from the gas outlet pipeline is still in gaseous form.

[0013] Further, the transmission plates between the gas inlet pipeline and the gas outlet pipeline can be arranged in various forms, such as a serpentine arrangement or a parallel arrangement.

[0014] The defoaming device comprises a shell, a filter screen and a distance rod. The shell is provided with a feeding port, a discharging port and a liquid discharge port on the outside. The filter screen is fixed in the shell and is fixed and positioned by the distance rod, so as to maintain the structural integrity and stability of the filter screen and realize effective gas-liquid separation.

[0015] Further, the filter screen is made of polytetrafluoroethylene.

[0016] Further, a plurality of grid structures are arranged between the filter screens, the filter screens are separated at intervals, and the interval of the grid structures is adjusted by the distance rods; the grid structures support the filter screens to prevent the filter screens from collapsing, and the filtering efficiency can be optimized by controlling the interval of the grid structures, thereby reducing the maintenance problems caused by excessive density or sparseness of the filter screens;

[0017] Further, the grid structure is a steel lining polytetrafluoroethylene grid material;

[0018] Further, the grid structure is a tile-shaped grid plate;

[0019] Further, the feed inlet is arranged at the bottom of one side of the skimming device shell, the discharge outlet is arranged at the top of the skimming device shell, and the bottom of the shell is provided with a liquid discharge port.

[0020] Compared with the prior art, the beneficial effects of the utility model are:

[0021] 1. The sulfur trioxide gas impurity removal device is first configured with a cooling device at the rear end of the fuming sulfuric acid evaporator, can reduce the temperature of the sulfur trioxide gas to about 80 DEG C, then transports the cooled sulfur trioxide gas to the skimming device, removes the acid mist in the sulfur trioxide gas in the skimming device, reduces the metal impurities and moisture in the sulfur trioxide gas, and significantly improves the purity and quality of the sulfur trioxide, which not only improves the quality of the product, but also avoids the damage of the high-temperature acidic environment to the equipment by reducing the device, effectively prolongs the service life of the device.

[0022] 2. By arranging the air inlet on the cooling device closer to the gas outlet pipeline, the air transported into the cooling device is used to cool the sulfur trioxide gas entering the gas transmission plate in the form of countercurrent heat exchange, the whole heat exchange process maintains the maximum temperature difference, thereby improving the heat transfer efficiency, and also helps to accurately control the temperature of the sulfur trioxide gas output from the gas outlet pipeline, ensuring the stability and controllability of the whole process.

[0023] 3. A fan is arranged at the air outlet of the cooling device to extract the air after heat exchange in the cooling device, the air after heat exchange can be recycled as hot air, and heat recovery is realized.

[0024] 4. The filter screen in the defoaming device is a polytetrafluoroethylene screen, which has good corrosion resistance, but is prone to collapse and other problems when exposed to a high-temperature environment above 100 DEG C for a long time. The smoke sulfuric acid evaporator is connected to the cooling device before the defoaming device to cool the sulfur trioxide gas, effectively prolonging the service life of the polytetrafluoroethylene screen, and further providing a technical solution using a grid structure. The grid structure has regular holes that allow the sulfur trioxide gas to pass through and fill the filter screen between adjacent grid structures, further improving the stability of the filter screen structure.

[0025] 5. The defoaming device is connected to the subsequent production line, so the effect of using the defoaming device to remove impurities from the sulfur trioxide gas is particularly important. The sulfur trioxide gas inlet is arranged at the bottom of one side of the defoaming device. This design is beneficial to the release of liquid droplets during the upward movement of the gas, allowing the liquid droplets to settle before reaching the top and being discharged separately through the liquid discharge port. This not only improves the heat exchange efficiency, but also prevents liquid accumulation, simplifies the cleaning and maintenance of the equipment, and ensures the efficient operation and long-term stability of the entire system. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Fig. 1 is a schematic view of the cooling device structure in the present application;

[0027] Figure 2 Fig. 2 is a schematic view of the defoaming device structure in the present application;

[0028] Figure 3 Fig. 3 is a connection process diagram of the equipment in the present application;

[0029] 1- cooling device, 11- air inlet, 12- air outlet, 13- gas inlet pipe, 14- gas outlet pipe, 15- tank body,

[0030] 2- defoaming device, 21- feed inlet, 22- discharge outlet, 23- liquid discharge port, 24- filter screen, 25- distance rod, 26- grid structure, 27- shell. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0033] Embodiment 1

[0034] A sulfur trioxide gas impurity removal device, comprising a cooling device 1 and a defoaming device 2 connected with the cooling device 1, and the sulfur trioxide impurity removal device is arranged at the rear end of a fuming sulfuric acid evaporator.

[0035] The structure of the cooling device 1 is shown in Figure 1 The tank body 15 of the cooling device 1 is provided with a gas inlet pipe 13 and a gas outlet pipe 14 in the transverse direction, the gas inlet pipe 13 is connected with the outlet of the fuming sulfuric acid evaporator through a pipe, and the gas outlet pipe 14 is connected with the feed inlet 21 on the shell of the defoaming device 2.

[0036] A gas transmission plate with a jacket is arranged in the tank body 15, and the gas transmission plate is connected with the gas inlet pipe 13 and the gas outlet pipe 14, as shown in Figure 1 The gas transmission plates are arranged in parallel, and in addition, the gas transmission plates can also be arranged in a serpentine shape or other arrangement forms.

[0037] In the tank body 15, air is introduced to exchange heat with the sulfur trioxide gas, the air is introduced into the tank body 15 from the air inlet 11 arranged at the top of the shell 15, and the air is extracted from the air outlet 12 by using a fan, wherein the air inlet 11 is arranged close to the gas outlet pipe 14, the air used for heat exchange and the sulfur trioxide gas flow in opposite directions, the temperature of the air used for heat exchange is 40-45℃, the air flowing in opposite directions can take away the excess heat of the sulfur trioxide gas, and after cooling, the temperature of the sulfur trioxide gas is reduced to about 80℃, so that the sulfur trioxide gas is cooled, the overheat of the evaporated sulfur trioxide gas is avoided to cause damage to the subsequent equipment, the air after heat exchange can be recycled as hot air, and heat recovery is realized.

[0038] As shown in Figure 2 The structure of the defoaming device 2 is shown in the figure, the sulfur trioxide gas is transported from the feed inlet 21 of the defoaming device 2 to the shell 27, acid droplets are entrained in the sulfur trioxide, the acid droplets contain a small amount of water and metal impurities, which affect the purity of the sulfur trioxide gas and the quality of the sulfuric acid product prepared by using the sulfur trioxide gas, so it is necessary to use the defoaming device 2 to remove the impurities of the sulfur trioxide gas, and the obtained sulfur trioxide gas is discharged from the discharge outlet 22 arranged at the top of the shell 27 for unified collection, the acid droplets are gathered at the bottom of the shell 27 and discharged through the liquid discharge port 23 arranged at the bottom of the shell 27, and the recovered acid droplets can be used again after being taken away.

[0039] The liquid discharge port 23 and the discharge outlet 22 are arranged on the center line of the tank body, so that the gas or liquid can be quickly discharged after being gathered.

[0040] The filter screen 24 is arranged inside the shell 27, and the filter screen 24 is fixed on the shell 27 by the distance rod 25. In order to further improve the firmness of the filter screen 24, a steel lining polytetrafluoroethylene grid structure 26 can be arranged between the filter screens 24. The distance rod 25 is used to adjust the interval of the grid structure 26, the filter screen 24 is filled between the adjacent grid structures 26, which can provide support for the filter screen 24 and adjust the density of the filter screen 24. In order to further improve the support ability of the grid structure 26 to the filter screen 24, the grid structure 26 is a tile row grid plate.

[0041] The sulfur trioxide gas carrying acid drops enters the shell 27 through the feed port 1, passes through the filter screen 24 through the holes on the grid structure 26. The acid drop liquid phase is heavier than the sulfur trioxide gas, and the acid drop is condensed on the filter screen 24. The acid drop is separated from the gas under the action of gravity, and the acid drop drops to the bottom of the shell 27. The sulfur trioxide gas is discharged from the discharge port 22 at the top of the shell 27.

[0042] The above is only the preferred embodiment of the present application, it should be pointed out that, for those skilled in the technical field, without departing from the principles of the present application, can also make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A sulfur trioxide gas polishing device, disposed at the downstream end of a fuming sulfuric acid evaporator, characterized by: The sulfur trioxide gas impurity removal device comprises a cooling device (1) and a defoaming device (2), the gas inlet pipeline (13) of the cooling device (1) is connected with the outlet of the fuming sulfuric acid evaporator through an external pipeline, the gas outlet pipeline (14) of the cooling device (1) is connected with the feeding port (21) of the defoaming device (2) through a pipeline, and the discharging port (22) of the defoaming device (2) is connected with subsequent equipment of the production line. The main body of the cooling device (1) is a tank body (15), the tank body (15) is provided with an air inlet (11) and an air outlet (12) at the top, respectively, and the tank body (15) is provided with a sulfur trioxide gas inlet pipeline (13) and a gas outlet pipeline (14) on the transverse direction, respectively; a gas transmission plate is arranged in the tank body (15), and the gas transmission plate is connected with the gas inlet pipeline (13) and the gas outlet pipeline (14) in communication. The defoaming device (2) comprises a shell (27), a filter screen (24) and a distance rod (25), the shell (27) is provided with a feeding port (21), a discharging port (22) and a liquid discharge port (23) on the outer side; the filter screen (24) is fixed in the shell (27), and the filter screen (24) and the shell (27) are fixed by the distance rod (25).

2. The sulfur trioxide gas impurity removal device of claim 1, wherein: The air inlet (11) is arranged close to the gas outlet pipeline (14), and the air outlet (12) is arranged close to the gas inlet pipeline (13).

3. The sulfur trioxide gas impurity removal device of claim 2, wherein: The air outlet (12) is provided with a fan.

4. The sulfur trioxide gas impurity removal device of claim 1, wherein: The transmission plates between the gas inlet pipeline (13) and the gas outlet pipeline (14) are arranged in a serpentine shape or in parallel.

5. The sulfur trioxide gas impurity removal device of claim 1, wherein: The filter screen (24) is a polytetrafluoroethylene filter screen.

6. The sulfur trioxide gas impurity removal device of claim 5, wherein: A plurality of grid structures (26) are arranged between the filter screens (24), and the grid structures (26) are adjusted in intervals by the distance rod (25).

7. The sulfur trioxide gas impurity removal device of claim 6, wherein: The grid structure (26) is made of steel lining polytetrafluoroethylene material.

8. The sulfur trioxide gas impurity removal device of any one of claims 6 or 7, wherein: The grid structure (26) is a tile-shaped grid plate.

9. The sulfur trioxide gas impurity removal device of claim 1, wherein: The feeding port (21) is arranged at the bottom of one side of the shell (27) of the defoaming device (2), the discharging port (22) is arranged at the top of the shell (27), and the shell (27) is provided with a liquid discharge port (23) at the bottom.

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