Acid gas absorption box

Abstract

The utility model discloses an acid gas absorption box which comprises a box body and an absorption frame in the box body, and a gas inlet and a gas outlet are arranged on a side plate of the box body. The absorption frames are flat absorption liquid channels with upper and lower openings, the flat absorption liquid channels are arranged in a staggered mode, and airflow flows in the box body in a zigzag mode. Two sides of a vertical plate of the absorption frame are hermetically connected with end plates, upper and lower ends of the vertical plate are connected with fixing plates, and the fixing plates are hermetically connected with a top plate and a bottom plate of the box body through connecting pieces. Through holes are evenly distributed in the vertical plate, grooves are formed around the through holes, the outer surface of the vertical plate is covered with a thin film, and the thin film is fixed through pressing strips matched with the grooves. The absorption frames are arranged in parallel or connected in series through flat bent pipes. In order to strengthen gas-liquid contact, the vertical plate is in a flat plate shape, an arc plate shape or a wave shape. According to the utility model, the gas-liquid channel is relatively independent, the gas-liquid contact area is large, the contact time is long, and the removal of acid gas is enhanced.

Description

Technical Field

[0001] This invention is applied in the chemical industry and relates to the removal of acidic gases from ethylene cracking gas, specifically an absorption box for absorbing acidic gases. Background Technology

[0002] During ethylene production, the cracked gas from hydrocarbon cracking needs to be compressed, have acid wash gases removed, dried, and refrigerated in a compression system. The acidic gases in the cracked gas are mainly carbon dioxide, hydrogen sulfide, and other gaseous sulfides, which are typically removed by alkaline washing or by washing with monoethanolamine and diethanolamine absorbents. The waste alkaline solution after alkaline washing needs to be treated to meet discharge standards, and the treatment cost for large quantities of waste alkaline solution is high. Ethanolamine absorbents have drawbacks such as equipment corrosion, volatility, and high regeneration energy consumption. CN119499859A describes a CO2 capturing absorbent, capturing and regenerating device, and capturing process, using ionic liquids as a novel acidic gas absorbent. Ionic liquids have advantages such as high thermal stability, low vapor pressure, and low corrosivity; their vapor pressure is almost zero, resulting in minimal loss during use. They also exhibit good absorption capacity and regeneration ability. Ionic liquids are highly designable and have ideal absorption effects, gradually becoming a major research focus for acidic gas absorption.

[0003] CN202161913U discloses an acidic gas absorption device. The absorbent liquid is pumped out, passes through a cooler, and then flows at high speed through a Laval nozzle. A negative pressure is created in the gas-liquid mixing chamber, drawing in acidic gas and mixing it with the highly turbulent absorbent liquid. The liquid resulting from the reaction of the absorbed gas and absorbent liquid flows out of the absorber and into an absorbent liquid storage tank for further absorption of acidic gas until all effective components in the absorbent liquid have been absorbed and reacted. CN204768217U discloses a device for removing acidic gases from chemical exhaust gases. The absorbent liquid inlet at the top of a spray absorption tower is connected to a spray head, and the chemical exhaust gas inlet is connected to an upward-facing jet nozzle. The spray head is located directly above the jet nozzle, and a conical shielding cap is installed on the jet nozzle, causing the gas to turbulently flow. This greatly increases the contact area between the mist-like absorbent liquid and the gas, improving absorption efficiency. The gas-liquid contact area and contact time of the above-mentioned technical solutions limit the absorption efficiency of acidic gases. Based on the technology of absorbing acidic gases with absorbent liquid, this utility model combines membrane permeability technology to develop an absorption box that can permeate and absorb acidic gases, thereby improving the absorption efficiency of acidic gases by increasing the gas-liquid contact area and contact time. Utility Model Content

[0004] The technical problem solved by this utility model is to provide an acid gas absorption box that uses a membrane to absorb acid gas through acid gas and ionic liquid to remove acid gas from cracked gas, increase the gas-liquid contact area and contact time, and improve the absorption efficiency of acid gas.

[0005] The technical solution adopted by this utility model is as follows: The acidic gas absorption box of this utility model includes a box body and an absorption frame inside the box body. The absorption frame is a flat absorption liquid channel with openings at the top and bottom. The absorption frames are alternately staggered in the box body, and the airflow flows in a zigzag pattern inside the box body. The box body is composed of a top plate, a bottom plate, and side plates. Gas inlets and gas outlets are provided on opposite side plates. The absorption frame includes a vertical plate, a fixed plate, and an end plate. The two sides of the vertical plate are sealed and fixedly connected to the end plates. The upper and lower ends of the vertical plate are fixedly connected to the fixed plates. The fixed plates are sealed and fixedly connected to the top plate and the bottom plate by connectors. The vertical plate has through holes evenly distributed. Grooves are provided on the outer surface around the through holes. The outer surface of the vertical plate is covered with a thin film, which is fixed by pressure strips that cooperate with the grooves.

[0006] Furthermore, a liquid inlet is provided below the bottom plate, and a liquid outlet is provided above the top plate, with the absorption frames arranged in parallel. Alternatively, the absorption frames are connected in series via flat-bent tubes, with a liquid outlet and a liquid inlet at both ends of the series-connected absorption frames.

[0007] Furthermore, the pore size of the through-holes in the film is 20-50 nanometers, and the thickness of the film does not exceed 500 micrometers.

[0008] Furthermore, the upright plate is flat, curved, or wavy.

[0009] The beneficial effects of this utility model are: This utility model adopts a combination of membrane permeability and absorbent liquid to absorb and remove acidic gases in the pyrolysis gas. The gas and liquid channels are relatively independent, the gas and liquid contact area is large, the contact time is long, and the acidic gas removal rate is high. Attached Figure Description

[0010] Figure 1 This is the main view of the structure in Example 1;

[0011] Figure 2 for Figure 1 A magnified view of a portion of the image;

[0012] Figure 3 for Figure 1 A schematic diagram of the AA cross-section;

[0013] Figure 4 for Figure 1 BB cross-sectional diagram;

[0014] Figure 5 This is a schematic diagram of a structure in Example 2;

[0015] Figure 6 This is a schematic diagram of another structure in Example 2;

[0016] Figure 7 This is a schematic diagram of the structure of Example 3;

[0017] Attached reference numerals: 1-Liquid outlet, 2-Top plate, 3-Absorption frame, 4-Gas outlet, 5-Bottom plate, 6-Liquid inlet, 7-Gas inlet, 8-Side plate;

[0018] 31-Vertical plate, 32-Film, 33-Through hole, 34-Pressure strip, 35-Connector, 36-Fixing plate, 37-End plate;

[0019] 41-Flat bend pipe. Detailed Implementation

[0020] The accompanying drawings of this utility model illustrate the absorption liquid flowing from bottom to top and the pyrolysis gas flowing from left to right, but this is not intended to limit the structural direction of this utility model. In the drawings, dashed arrows indicate the gas flow direction, and solid arrows indicate the liquid flow direction. Example

[0021] The structure of the acid gas absorption box in this embodiment is shown in the attached figure. Figure 1-4 As shown, it includes a housing and an absorption frame 3 installed inside the housing. The housing consists of a top plate 2, a bottom plate 5, and side plates 8, as shown in the attached diagram. Figure 1 As shown, an air inlet 7 is provided on the left side plate, an air outlet 4 is provided on the right side plate, a liquid inlet 6 is provided above the bottom plate 5, and a liquid outlet 1 is provided below the top plate 2. The direction of liquid flow is perpendicular to the direction of gas flow.

[0022] The absorption frame 3 has an opening structure at the top and bottom, including a vertical plate 31 and an end plate 37, as shown in the attached figure. Figure 2 and attached Figure 3 As shown, the two vertical plates are sealed and fixedly connected to end plates 37 on both sides, thus forming a liquid channel with openings at the top and bottom of the absorption frame 3. The upper and lower ends of the vertical plate 31 are sealed and fixedly connected to fixing plates 36. The upper fixing plate 36 is sealed and fixedly connected to the top plate 2 using connectors 35, and the upper opening of the absorption frame 3 is connected to the liquid outlet 1; the lower fixing plate 36 is sealed and fixedly connected to the bottom plate 5 using connectors 35, and the lower opening of the absorption frame 3 is connected to the liquid inlet 6. Through holes 33 are evenly distributed on the vertical plate 31, and grooves are formed on the outer surface around the through holes 33. A film 32 covers the outer surface of the vertical plate 31, and a pressure strip 34 cooperates with the grooves to fix the film 32, as shown in the attached diagram. Figure 4 As shown. A vertical plate 31 is used to fix and support the membrane 32, preventing damage to the membrane and improving its service life. The membrane separates the gas and liquid, making the gas and liquid channels relatively independent.

[0023] Multiple flat absorption frames 3 are installed inside the chamber to increase the gas-liquid contact area. The absorption frames 3 are arranged alternately and staggered inside the chamber, as shown in the attached diagram. Figure 3 As shown, this causes the pyrolysis gas to flow in a zigzag pattern within the chamber, creating turbulence, increasing the contact time between the gas and the membrane, and ensuring sufficient contact.

[0024] In this embodiment, the absorbent enters the absorption frame 3 through the liquid inlet 6. After absorbing the acidic gas in the absorption frame, it flows out through the liquid outlet 1 and is sent to the absorbent regeneration tower. The low-temperature pyrolysis gas enters the chamber through the gas inlet 7. During the turbulent flow process in the chamber, the acidic gas permeates through the membrane 32 into the absorbent in the absorption frame. The pyrolysis gas with the acidic gas removed flows out through the gas outlet 4 and enters the next process.

[0025] The membrane can be made of silicone rubber, polytetrafluoroethylene (PTFE), or polypropylene (PP). Silicone rubber molecular chains have high flexibility and weak intermolecular forces, allowing gas molecules to diffuse easily. PTFE has a highly symmetrical molecular structure, high crystallinity, and relatively large gaps between molecular chains. The methyl groups on the PP molecular chains create gaps between the chains. These membranes exhibit good permeability to acidic gases, good corrosion resistance and chemical stability, and high strength, making them ideal for filtration of acidic gases. To enhance the absorption of acidic gases, the pore size of the membrane should be 20-50 nanometers, and the thickness should preferably not exceed 500 micrometers. To further enhance the absorption of acidic gases, the pressure of the pyrolysis gas should be higher than the pressure of the absorbent liquid within the absorption frame. Increasing the area of ​​the pores and employing turbulent flow of the pyrolysis gas will increase the contact area and opportunity between the gas and the membrane.

[0026] The absorbent uses ionic liquid absorbents, such as modified 1-butyl-3-methylimidazolium tetrafluoroborate or amino acid-based ionic liquids. Example

[0027] This implementation is an improvement on the shape of the absorption frame in Example 1, as shown in the attached figure. Figure 5 and attached Figure 6 As shown, the vertical plate of the absorption frame in Example 1 is flat, while the vertical plate of the absorption frame 3 in this example is arc-shaped or wavy. This serves two purposes: 1) to increase the surface area of ​​the vertical plate, thereby increasing the area of ​​the through holes and the gas-liquid contact area; 2) the change in the cross-sectional dimensions of the gas channels between the absorption frames is more conducive to the formation of gas turbulence. The change in the shape of the vertical plate in this example enhances the absorption of acidic gases in the cracked gas. Example

[0028] The structure of the absorption box in this implementation is shown in the attached figure. Figure 7 As shown, in the above embodiment, the absorption frames are arranged side by side. In this embodiment, the absorption frames 3 are arranged in series by flat bend pipes 41. The flat bend pipes 41 are oblique and cooperate with the alternately staggered absorption frames. This embodiment not only reduces the volume space of the tank, but also allows the inlet and outlet positions of the absorbent liquid to be changed by adjusting the number of absorption frames, which facilitates reasonable pipeline layout according to actual conditions.

[0029] In this invention, all plate materials should preferably be acid-resistant organic polymer materials, such as polytetrafluoroethylene (PTFE) or polypropylene (PP), to improve the service life of the absorption box.

[0030] This invention combines a membrane-permeable membrane with an absorbent liquid to absorb and remove acidic gases from pyrolysis gas. The gas and liquid channels are relatively independent, resulting in a large gas-liquid contact area and long contact time. The flowing absorbent liquid is unaffected by gas partial pressure, leading to a high acidic gas removal rate. This invention has a simple structure and low manufacturing and operating costs.

Claims

1. An acidic gas absorption box, characterized in that: Includes a housing and an absorption frame (3) installed inside the housing. The housing is composed of a top plate, a bottom plate and a side plate. An air inlet and an air outlet are provided on the opposite side plates. The absorption frame (3) is a flat channel with openings at the top and bottom. The absorption frames (3) are alternately staggered. The absorption frame (3) includes a vertical plate (31) and an end plate (37); the two sides of the vertical plate (31) are sealed to the end plate (37), and the two ends of the vertical plate (31) are sealed to the fixing plate (36). The fixing plate (36) is sealed to the top plate and the bottom plate by means of a connector (35); through holes (33) are evenly distributed on the vertical plate (31), and grooves are provided on the outer surface around the through holes (33). A thin film (32) is covered on the outer surface of the vertical plate (31), and the thin film (32) is fixed by a pressure strip (34) that cooperates with the groove.

2. The acidic gas absorption box according to claim 1, characterized in that: A liquid inlet is provided below the bottom plate, and a liquid outlet is provided above the top plate. The absorption frames (3) are arranged in parallel.

3. The acidic gas absorption box according to claim 1, characterized in that: The absorption frame (3) is connected in series via a flat curved tube (41).

4. The acidic gas absorption box according to claim 1, characterized in that: The pore size of the through-holes in the film (32) is 20-50 nanometers, and the thickness of the film (32) is no more than 500 micrometers.

5. The acidic gas absorption box according to claim 1, characterized in that: The vertical plate (31) is flat, curved, or wavy.

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