Stripping tower suitable for high-temperature negative-pressure corrosion working condition

Abstract

The utility model relates to a stripping tower suitable for high-temperature negative-pressure corrosion working condition in the field of chemical industry, which at least comprises four shell rings which are sequentially connected from top to bottom, an end cover is arranged on the top surface of a first shell ring, a gas outlet is arranged at the top of the end cover, a demister is arranged at the bottom of the first shell ring, a sulfuric acid inlet is arranged on the side wall of a second shell ring, and a gas outlet is arranged at the bottom of the second shell ring. A packing layer is arranged at the lower section of the third shell ring, a packing pressing plate with a grid structure is arranged on the top surface of the packing layer, a packing supporting plate with a grid structure is arranged at the bottom of the packing layer, a damp and hot gas inlet is formed in the side wall of the fourth shell ring, and a liquid phase outlet is formed in the bottom of the fourth shell ring. The steam stripping device is suitable for high-temperature negative-pressure corrosion working conditions, simple in structure, low in manufacturing cost, easy to overhaul, good in steam stripping effect and capable of flexibly adjusting the steam stripping effect.

Description

Technical Field

[0001] The utility model relates to a stripping column of an AHF device in the chemical industry field, specifically a stripping column applicable to high-temperature and negative-pressure corrosion working conditions. Background Art

[0002] The reacted sulfuric acid contains a certain amount of HF, and the HF in the sulfuric acid is removed in the stripping column. 60% - 90% sulfuric acid is obtained at the bottom of the stripping column, and the stripped gas-phase components enter the subsequent absorption and washing system.

[0003] To improve the stripping effect, the operating temperature in the stripping column is 150 - 200°C and it operates under negative pressure; the medium contains high-concentration sulfuric acid and a small amount of F - plasma, and the comprehensive corrosion is very strong at high temperatures. The HF concentration in the stripped gas-phase components is high, and HF has strong corrosiveness and permeability in a humid and high-temperature environment. The liquid phase contains a small amount of SiO2 and has certain abrasiveness.

[0004] The existing stripping columns have the following problems: 1) It is difficult to select the cylinder wall material under the conditions of high temperature and high corrosion, strong-permeability medium, and negative-pressure working conditions. Using high-alloy materials has a high investment, while using a steel-lined fluoroplastic structure, the fluoroplastic lining at the process medium inlet and outlet and local high-temperature areas is easily damaged, the cylinder wall is easily corroded, the service life is short, the maintenance and replacement are relatively frequent, and the structural reliability is poor. 2) The tower body structure is relatively fixed, and it cannot flexibly control the stripping effect and is not convenient for maintenance; 3) The stripping efficiency still needs to be further improved. Summary of the Invention

[0005] The purpose of the utility model is to solve the above technical problems and provide a stripping column applicable to high-temperature and negative-pressure corrosion working conditions, which has a simple structure, low manufacturing cost, is easy to maintain, has a good stripping effect, and can flexibly adjust the stripping effect.

[0006] The stripping column of the utility model at least includes four cylinder sections connected in sequence from top to bottom. Among them, the top surface of the first cylinder section is provided with an end cover, a gas outlet is provided at the top of the end cover, a demister is provided at the bottom of the first cylinder section, a sulfuric acid inlet is provided on the side wall of the second cylinder section, a packing layer is installed in the lower section of the third cylinder section, a packing pressing plate with a grid structure is provided on the top surface of the packing layer, and a packing support plate with a grid structure is provided at the bottom. A humid gas inlet is provided on the side wall of the fourth cylinder section, and a liquid phase outlet is provided at the bottom.

[0007] A liquid distributor is provided at the bottom of the second cylinder section.

[0008] A liquid collection and distribution cone is provided on the bottom surface of the packing support plate at the bottom of the third cylinder section, and the reduced-diameter end of the liquid collection and distribution cone extends into the fourth cylinder section.

[0009] The barrel wall structures of the second barrel section and the fourth barrel section are composed of, from outside to inside, a steel shell, a fluoroplastic lining, and a hard non-metallic lining ring in sequence. The hard non-metallic lining ring can be selected from carbon materials, graphite materials, silicon carbide, etc.

[0010] The hard non-metallic lining ring is formed by splicing multiple arc-shaped lining tiles, and resin mortar is filled in the splicing gaps.

[0011] Two adjacent lining tiles are fitted and locked by means of a concave-convex structure.

[0012] The barrel sections are detachably connected.

[0013] The third barrel section and the fourth barrel section are taken as a group, and more than two groups can be connected continuously.

[0014] In the present utility model, multiple barrel sections can be detachably connected, such as by using a flange connection method. On the one hand, it is easy to assemble, overhaul, and replace; on the other hand, the barrel sections can be increased or decreased according to the stripping requirements, with good flexibility and adaptability. On this basis, the third and fourth barrel sections are taken as a group, and more than two groups can be connected to form stripping more than twice. A liquid distributor is provided at the bottom of the second barrel section, which is beneficial to the uniform distribution of the liquid; a liquid collection and distribution cone is provided on the bottom surface of the packing support plate at the bottom of the third barrel section to drain the liquid, prevent the high-temperature liquid from forming wall flow, form a preliminary redistribution of the liquid, and improve the contact between the liquid and gas phases; and it reduces the corrosion and abrasion erosion of the wall part, effectively protecting the local fluoroplastic lining. A fluoroplastic lining is still used at the local high-temperature barrel section to form a dense corrosion-resistant layer, a hard non-metallic lining ring is provided to separate most of the media, and the hard non-metallic lining ring tightly supports the fluoroplastic lining, reducing the creep deformation of the fluoroplastic lining at high temperature, or the risk of being sucked inwards or peeled off towards the inside under a negative pressure condition, and improving the high-temperature creep resistance and negative pressure resistance.

[0015] The structure of the present utility model is simple, easy to produce and manufacture, with low investment and operation costs, good stripping efficiency, good flexibility and adaptability, easy to overhaul and maintain, and applicable to high-temperature negative-pressure corrosion conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the present utility model.

[0017] Figure 2 It is a partial cross-sectional view of the second barrel section and the fourth barrel section.

[0018] Among them, 1 - end cover, 1.1 - gas outlet, 2 - first cylinder section, 2.1 - demister, 3 - second cylinder section, 3.1 - sulfuric acid inlet, 3.2 - liquid distributor, 4 - third cylinder section, 4.1 - packing pressing plate, 4.2 - packing layer, 4.3 - packing support plate, 4.4 - liquid collection and distribution cone, 5 - fourth cylinder section, 5.1 - humid and hot gas inlet, 5.2 - liquid phase outlet, 6.1 - steel shell, 6.2 - fluoroplastic lining, 6.3 - fluoroplastic lining weld, 6.4 - hard non-metallic lining ring, 6.5 - groove, 6.6 - resin mortar. Detailed implementation manners

[0019] The present utility model will be further explained with reference to the accompanying drawings as follows:

[0020] See Figure 1 , the stripping tower of the present utility model includes four cylinder sections connected in sequence from top to bottom, and the cylinder sections are detachably connected.

[0021] Among them, the top surface of the first cylinder section 2 is provided with an end cover 1, the top of the end cover 1 is provided with a gas outlet 1.1, the bottom of the first cylinder section 2 is provided with a demister 2.1 for removing liquid droplets in the gas phase, the side wall of the second cylinder section 3 is provided with a sulfuric acid inlet 3.1, and the bottom is provided with a liquid distributor 3.2 to evenly distribute the liquid phase. The lower section of the third cylinder section 4 is equipped with a packing layer 4.2, the top surface of the packing layer 4 is provided with a packing pressing plate 4.1 with a grid structure, the bottom is provided with a packing support plate 4.3 with a grid structure, and the bottom surface of the packing support plate 4.3 is provided with a liquid collection and distribution cone 4.4. The reduced-diameter end of the liquid collection and distribution cone 4.4 extends into the fourth cylinder section 5. The side wall of the fourth cylinder section 5 is provided with a humid and hot gas inlet 5.1 and the bottom is provided with a liquid phase outlet 5.2.

[0022] The inventor has studied and found that: generally, the cylinder section can be composed of a steel shell 6.1 and a fluoroplastic lining 6.2. However, during operation, the cylinder sections where the sulfuric acid inlet 3.1 and the humid and hot gas inlet 5.1 are located have high operating temperatures, and the reliability of the fluoroplastic lining decreases under high-temperature working conditions, or it is easily damaged under the repeated action of thermal expansion and contraction during startup and shutdown. Moreover, the steel shell cannot resist medium corrosion, and the leakage of the medium may bring safety risks.

[0023] The inventors' design structure for the cylinder walls of the second cylinder section 3 and the fourth cylinder section 5 is as follows: from the outside to the inside, it consists of a steel shell 6.1, a fluoroplastic lining 6.2, and a hard non-metallic lining ring 6.4 in sequence. Preferably, after setting the fluoroplastic lining 6.2 on the steel shell 6.1, a layer of hard non-metallic lining ring 6.4 is built inside. If the diameter of the steel shell 6.1 is small, the hard non-metallic lining ring 6.4 can be made into an integral circular ring structure. However, if the diameter of the steel shell 6.1 is large, the hard non-metallic lining ring is composed of multiple arc-shaped lining tiles that are fitted and locked together using a concave-convex structure. The gap between the adjacent two lining tiles is filled with resin mortar 6.6 to tightly support the fluoroplastic lining 6.2. In this way, the fluoroplastic lining 6.2 forms a complete dense corrosion-resistant layer to protect the steel shell 6.1.

[0024] The hard non-metallic lining ring 6.4 can be made of carbon materials, graphite materials, silicon carbide, etc. The hard non-metallic lining ring 6.2 prevents the high-temperature medium from directly acting on the surface of the fluoroplastic lining, avoids the abrasion of the medium on the fluoroplastic lining, and due to the isolation of the hard non-metallic lining ring, the temperature on the surface of the fluoroplastic lining is reduced, extending the service life; the hard non-metallic lining ring tightly supports the fluoroplastic lining, reducing the creep deformation of the fluoroplastic lining at high temperatures, or the risk of being sucked inwards or peeled off towards the inside under negative pressure conditions, improving the high-temperature creep resistance and negative pressure resistance.

[0025] Process: The feed medium (sulfuric acid with a concentration of 60% - 90% and containing a small amount of HF) enters the second cylinder section 3 from the sulfuric acid inlet 3.1, and evenly enters the packing section 4.2 of the third cylinder section 4 through the liquid distributor 3.2. The wet and hot gas enters the fourth cylinder section 5 from the wet and hot gas inlet 5.1. The sulfuric acid encounters the wet and hot gas and dilutes with heat release. The solubility of HF in the sulfuric acid decreases and becomes a gas phase and comes out. The HF that comes out goes up with the wet and hot gas, passes through the demister 2.1, removes the large particle liquid droplets, and then is discharged from 1.1 on the end cover 1. After the sulfuric acid is diluted and stripped, it is discharged from the bottom liquid phase outlet 5.2, achieving the purpose of stripping HF in the sulfuric acid with the wet and hot gas.

[0026] As another implementation, the third cylinder section 4 and the fourth cylinder section 5 are in a group and can be connected continuously in two groups, thus forming the effect of two-stage packing and two-stage stripping. After testing, for the two-stage packing, the HF overflow effect can be increased from 70% to 85% - 90% after stripping.

Claims

1. A stripping tower suitable for high temperature negative pressure corrosion conditions, comprising at least four cylinder sections connected in sequence from top to bottom, wherein: An end cover is provided on the top surface of the first cylinder segment, and a gas outlet is provided on the top of the end cover. The invention is characterized in that a demister is provided at the bottom of the first cylinder segment, a sulfuric acid inlet is provided on the side wall of the second cylinder segment, a packing layer is provided on the lower section of the third cylinder segment, a packing pressure plate with a grid structure is provided on the top surface of the packing layer, and a packing support plate with a grid structure is provided on the bottom, a hot and humid gas inlet is provided on the side wall of the fourth cylinder segment, and a liquid phase outlet is provided on the bottom.

2. The stripping tower suitable for high temperature negative pressure corrosion conditions as claimed in claim 1, characterized in that: A liquid distributor is provided at the bottom of the second cylinder section.

3. The stripping tower suitable for high temperature negative pressure corrosion conditions as claimed in claim 1, characterized in that: A liquid collecting and distributing cone is provided on the bottom surface of the filler support plate at the bottom of the third cylinder section, and the reduced diameter end of the liquid collecting and distributing cone extends into the fourth cylinder section.

4. The stripping tower suitable for high temperature negative pressure corrosion conditions as claimed in claim 1, characterized in that: The cylinder wall structure of the second cylinder segment and the fourth cylinder segment is composed of a steel shell, a fluoroplastic lining and a hard non-metallic lining ring from the outside to the inside.

5. The stripping tower suitable for high temperature negative pressure corrosion conditions as claimed in claim 4, characterized in that: The hard non-metal lining ring is formed by splicing a plurality of arc-shaped lining tiles, and resin cement is filled in the gaps between the spliced ​​pieces.

6. The stripping tower suitable for high temperature negative pressure corrosion conditions as claimed in claim 5, characterized in that: Two adjacent lining tiles are locked together using a concave-convex structure.

7. The stripping tower suitable for high temperature negative pressure corrosion conditions according to any one of claims 1 to 6, characterized in that: The cylinder sections are detachably connected.

8. The stripping tower suitable for high temperature negative pressure corrosion conditions according to claim 7, characterized in that: The third cylinder segment and the fourth cylinder segment form a group, and two or more groups can be connected continuously.

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