Concentrated sulfuric acid dehydration device for chlorine drying system

Abstract

The utility model relates to a concentrated sulfuric acid dehydration device for a chlorine drying system, which comprises a bubble-cap tower and a packed tower, and is technically characterized in that the tail end of a concentrated sulfuric acid overflow pipeline of a tower kettle at the lower part of the bubble-cap tower is connected with an observation sight glass, the other end of the observation sight glass is connected with an inlet at the lower part of a dehydration tank through a feeding pipeline, and the dehydration tank is filled with anhydrous sodium sulfate; the other end of the concentrated solution outlet pipeline of the dehydration tank is connected with the bottom of the packed tower, an overhaul bypass is arranged between the concentrated solution outlet pipeline of the dehydration tank and the feeding pipeline, a gas-liquid balance pipeline is arranged at the top of the dehydration tank, and the other end of the gas-liquid balance pipeline is communicated with a tower kettle at the lower part of the bubble-cap tower; and the feeding pipeline is additionally provided with a high-position branch communicated with the gas-liquid balance pipeline. According to the device, the concentration of concentrated sulfuric acid entering the packed tower is increased, the chlorine drying effect is improved, the use amount of concentrated sulfuric acid is reduced, the utilization rate of concentrated sulfuric acid is improved, anhydrous sodium sulfate is recycled, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chlor-alkali production equipment, and particularly relates to a concentrated sulfuric acid dehydration device for a chlorine drying system. Background Technique

[0002] Concentrated sulfuric acid is a strong mineral acid with high corrosiveness and is a sulfuric acid solution with a mass fraction greater than or equal to 70%. Concentrated sulfuric acid has strong oxidizing properties at high concentrations, which is one of the biggest differences between it and ordinary sulfuric acid or ordinary concentrated sulfuric acid. At the same time, concentrated sulfuric acid contains a large number of undissociated sulfuric acid molecules, so it also has water absorption and dehydration properties.

[0003] In the process of chlor-alkali production, the water absorption property of concentrated sulfuric acid and the characteristic of not reacting with chlorine gas are often used to dry chlorine gas. Concentrated sulfuric acid first flows from top to bottom in a bubble-cap column and directly contacts with chlorine gas. After that, the concentration of concentrated sulfuric acid changes from 98% to 95%, and then it overflows into a packed column. After passing through a circulation pump, it directly contacts with chlorine gas from top to bottom and becomes 75% dilute sulfuric acid. Finally, it overflows into a dilute acid tank and is treated as hazardous waste. This operation will cause waste of resources. Therefore, in order to reduce the consumption of concentrated sulfuric acid, the existing technology is to evaporate the excess water in the dilute sulfuric acid by steam heating, and then use circulating water and chilled water to cool down to achieve the concentration increase and recycling of dilute sulfuric acid. However, there are still the following problems: This recovery process has high energy consumption, requires high-quality materials for equipment pipelines, has high production costs, and does not have practical application value. Content of the Utility Model

[0004] The purpose of the utility model is to provide a concentrated sulfuric acid dehydration device for a chlorine drying system with reasonable configuration and reliable use, which can dehydrate the 95% concentrated sulfuric acid overflowing from the intermediate process of the chlorine drying system, namely the bubble-cap column, so as to increase the concentration of concentrated sulfuric acid entering the packed column, improve the drying effect on chlorine gas, reduce the usage amount of concentrated sulfuric acid, improve the utilization rate of concentrated sulfuric acid, and at the same time realize the recycling of anhydrous sodium sulfate and reduce the production cost.

[0005] The technical solution of the utility model is as follows:

[0006] A concentrated sulfuric acid dehydration device for a chlorine gas drying system, comprising a bubble cap tower and a packed tower. The top of the bubble cap tower is provided with a concentrated sulfuric acid feeding pipeline, and the lower tower kettle of the bubble cap tower is provided with a concentrated sulfuric acid overflow pipeline. The technical key points are as follows: The end of the concentrated sulfuric acid overflow pipeline is connected to an observation sight glass, and the other end of the observation sight glass is connected to the lower inlet of a dehydration tank through a feeding pipeline. The dehydration tank is filled with anhydrous sodium sulfate, a by-product of chlor-alkali production. The upper side wall of the dehydration tank is provided with a concentrated liquid outlet pipeline, and the other end of the concentrated liquid outlet pipeline is connected to the concentrated sulfuric acid inlet at the bottom of the packed tower. A two-stage circulation pump communicating with its tower kettle is arranged outside the bubble cap tower, and the outlet pipeline of the two-stage circulation pump is communicated with the first layer of tower plates of the bubble cap tower. A circulation pipeline is arranged between the bottom and the top of the packed tower, and a one-stage circulation pump is arranged on the circulation pipeline. A maintenance bypass is arranged between the concentrated liquid outlet pipeline and the feeding pipeline of the dehydration tank. The top of the dehydration tank is provided with a gas-liquid balance pipeline, and the other end of the gas-liquid balance pipeline is communicated with the lower tower kettle of the bubble cap tower. The feeding pipeline is also provided with a high-level branch communicated with the gas-liquid balance pipeline.

[0007] For the above-mentioned concentrated sulfuric acid dehydration device for a chlorine gas drying system, a chlorine gas inlet pipeline is arranged on the side wall of the packed tower at a position below the anhydrous sodium sulfate packing layer. A chlorine gas conveying pipeline is arranged between the top of the packed tower and the lower tower kettle of the bubble cap tower, and a chlorine gas output pipeline is arranged at the top of the bubble cap tower.

[0008] For the above-mentioned concentrated sulfuric acid dehydration device for a chlorine gas drying system, a sprayer communicated with the circulation pipeline is arranged inside the top of the packed tower.

[0009] For the above-mentioned concentrated sulfuric acid dehydration device for a chlorine gas drying system, a first control valve is arranged at the end of the feeding pipeline close to the dehydration tank, a second control valve is arranged at the starting end of the concentrated liquid outlet pipeline of the dehydration tank, a third control valve is arranged at the starting end of the gas-liquid balance pipeline, a fourth control valve is arranged on the maintenance bypass, and a fifth control valve is arranged at the end of the gas-liquid balance pipeline.

[0010] The beneficial effects of the present utility model are as follows:

[0011] 1. The 98% concentrated sulfuric acid in the bubble cap tower flows from top to bottom and directly contacts the chlorine gas countercurrently, turning into 95% concentrated sulfuric acid. The concentrated sulfuric acid in the tower kettle of the bubble cap tower is sent to the first layer of tower plates through a two-stage circulation pump for circulation. The 95% concentrated sulfuric acid overflowing from the tower kettle of the bubble cap tower enters the dehydration tank after passing through the observation sight glass. The dehydrated concentrated sulfuric acid enters the packed tower and is sent to the top of the packed tower through a one-stage circulation pump, flowing from top to bottom and directly contacting the chlorine gas countercurrently to remove the water in the chlorine gas. Compared with the existing process where the 95% concentrated sulfuric acid in the bubble cap tower directly overflows into the packed tower, the present utility model improves the concentration of the sulfuric acid entering the packed tower by adding a dehydration tank, not only improving the dehydration effect but also reducing the consumption of concentrated sulfuric acid and the production cost.

[0012] 2. The desiccant inside the dehydration tank uses anhydrous sodium sulfate, a byproduct of chlor-alkali production. Utilizing its characteristics of being insoluble in concentrated sulfuric acid and its water absorption property, it is used for further concentration of 95% concentrated sulfuric acid. Anhydrous sodium sulfate, as a byproduct of chlor-alkali production, is generally treated as hazardous waste. In this application, using it as a desiccant not only saves the procurement cost of the desiccant but also provides a new direction for the use of the byproduct anhydrous sodium sulfate.

[0013] 3. A gas-liquid balance pipeline is connected between the top of the dehydration tank and the bubble-cap column to ensure the smooth overflow of concentrated sulfuric acid.

[0014] 4. An overhaul bypass is provided between the concentrated liquid outlet pipeline of the dehydration tank and the feeding pipeline. When replacing or replenishing the desiccant, it can be switched to the overhaul bypass without affecting the normal overflow of concentrated sulfuric acid, so as to ensure stable production. Brief Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the present utility model.

[0016] In the figure: 1. Bubble-cap column, 2. Observation sight glass, 3. Gas-liquid balance pipeline, 4. Dehydration tank, 5. Packed column, 6. Overhaul bypass, 7. Second-stage circulation pump, 8. First-stage circulation pump, 9. Concentrated sulfuric acid feeding pipeline. Detailed Description of the Embodiment

[0017] The present utility model will be described in detail according to the accompanying drawings of the specification.

[0018] As Figure 1 shown, the concentrated sulfuric acid dehydration device for the chlorine drying system includes a bubble-cap column 1 and a packed column 5. The top of the bubble-cap column 1 is provided with a concentrated sulfuric acid feeding pipeline 9, and the lower tower kettle of the bubble-cap column 1 is provided with a concentrated sulfuric acid overflow pipeline.

[0019] Among them, the end of the concentrated sulfuric acid overflow pipeline is connected to the observation sight glass 2, and the other end of the observation sight glass 2 is connected to the lower inlet of the dehydration tank 4 through a feeding pipeline. The dehydration tank 4 is filled with anhydrous sodium sulfate, a byproduct of chlor-alkali production. The upper side wall of the dehydration tank 4 is provided with a concentrated liquid outlet pipeline, and the other end of the concentrated liquid outlet pipeline is connected to the concentrated sulfuric acid inlet at the bottom of the packed column 5. A second-stage circulation pump 7 communicated with its tower kettle is arranged outside the bubble-cap column 1, and the outlet pipeline of the second-stage circulation pump 7 is communicated with the first-layer tower plate of the bubble-cap column 1. A circulation pipeline is provided between the bottom and the top of the packed column 5, a first-stage circulation pump 8 is arranged on the circulation pipeline, and a sprayer communicated with the circulation pipeline is arranged inside the top of the packed column 5.

[0020] An inspection bypass 6 is provided between the concentrated liquid outlet pipeline and the feeding pipeline of the dehydration tank 4. A gas-liquid balance pipeline 3 is provided at the top of the dehydration tank 4, and the other end of the gas-liquid balance pipeline 3 is communicated with the lower tower kettle of the bubble-cap column 1. The feeding pipeline is additionally provided with a high-position branch communicated with the gas-liquid balance pipeline 3. A first control valve is provided at the end of the feeding pipeline close to the dehydration tank 4, a second control valve is provided at the starting end of the concentrated liquid outlet pipeline of the dehydration tank 4, a third control valve is provided at the starting end of the gas-liquid balance pipeline 3, a fourth control valve is provided on the inspection bypass 6, and a fifth control valve is provided at the end of the gas-liquid balance pipeline 3.

[0021] In this embodiment, a chlorine gas inlet pipeline is provided on the side wall of the packed tower 5 at a position below the anhydrous sodium sulfate packing layer. A chlorine gas transmission pipeline is provided between the top of the packed tower 5 and the lower tower kettle of the bubble-cap column 1. A chlorine gas output pipeline is provided at the top of the bubble-cap column 1.

[0022] Working principle:

[0023] In the bubble-cap column 1, 98% concentrated sulfuric acid flows from top to bottom and directly contacts chlorine gas in countercurrent, becoming 95% concentrated sulfuric acid. The concentrated sulfuric acid in the tower kettle of the bubble-cap column 1 is sent to the first layer of tower plate of the bubble-cap column 1 by the second-stage circulation pump 7 for circulation. The 95% concentrated sulfuric acid overflowing from the tower kettle of the bubble-cap column 1 enters the dehydration tank 4 after passing through the observation sight glass 2. The dehydrated concentrated sulfuric acid enters the packed tower 5 and is sent to the top of the packed tower 5 by the first-stage circulating acid pump 8. It flows from top to bottom and directly contacts chlorine gas in countercurrent to remove the water in the chlorine gas.

[0024] The above has described the embodiments of the present invention in detail, but the above content is only the preferred embodiments of the present invention and cannot be considered as limiting the implementation scope of the present invention. All equal changes and improvements made within the scope of the present invention should still fall within the scope covered by this patent.

Claims

1. A concentrated sulfuric acid dehydration device for a chlorine drying system, comprising a bubble tower and a packing tower, wherein a concentrated sulfuric acid feeding pipeline is provided at the top of the bubble tower, and a concentrated sulfuric acid overflow pipeline is provided at the bottom of the bubble tower, characterized in that: The end of the concentrated sulfuric acid overflow pipeline is connected to an observation mirror, and the other end of the observation mirror is connected to the lower inlet of the dehydration tank by a feeding pipeline. The dehydration tank is filled with anhydrous sodium sulfate, a by-product of chlor-alkali production. A concentrated liquid outlet pipeline is provided on the upper side wall of the dehydration tank, and the other end of the concentrated liquid outlet pipeline is connected to the concentrated sulfuric acid inlet at the bottom of the packing tower. A two-stage circulation pump connected to the tower kettle of the bubble tower is provided on the outside of the bubble tower, and the outlet pipeline of the two-stage circulation pump is connected to a layer of tower plates of the bubble tower. A circulation pipeline is provided between the bottom and the top of the packing tower, and a section of the circulation pump is provided on the circulation pipeline. A maintenance bypass is provided between the concentrated liquid outlet pipeline of the dehydration tank and the feeding pipeline. A gas-liquid balance pipeline is provided on the top of the dehydration tank, and the other end of the gas-liquid balance pipeline is connected to the lower tower kettle of the bubble tower. The feeding pipeline is further provided with a high-level branch connected to the gas-liquid balance pipeline.

2. The concentrated sulfuric acid dehydration device for chlorine drying system according to claim 1, characterized in that: A chlorine inlet pipeline is arranged on the side wall of the packing tower below the anhydrous sodium sulfate packing layer, a chlorine delivery pipeline is arranged between the top of the packing tower and the lower tower kettle of the bubble tower, and a chlorine output pipeline is arranged on the top of the bubble tower.

3. The concentrated sulfuric acid dehydration device for chlorine drying system according to claim 1, characterized in that: A sprayer connected to the circulation pipeline is provided on the inner side of the top of the packed tower.

4. The concentrated sulfuric acid dehydration device for a chlorine drying system according to claim 1, characterized in that: A first control valve is provided at the feeding pipeline near the dehydration tank end, a second control valve is provided at the starting end of the concentrated liquid outlet pipeline of the dehydration tank, a third control valve is provided at the starting end of the gas-liquid balance pipeline, a fourth control valve is provided on the maintenance bypass, and a fifth control valve is provided at the end of the gas-liquid balance pipeline.

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