A new type of accident chlorine gas absorption device

Abstract

The utility model belongs to chlorine gas absorption technical field, specifically disclose a novel accident chlorine gas absorption device, including primary accident tower and secondary accident tower, the secondary accident tower is fixed in primary accident tower top, is connected with the draught fan in the secondary accident tower top, is provided with chlorine gas release pipeline in primary accident tower side, is provided with the secondary sodium circulating pump in primary accident tower bottom and is connected with secondary sodium circulating pump's input, is connected with secondary sodium heat exchanger in secondary sodium circulating pump's output, is connected with secondary sodium circulating pipeline between secondary sodium heat exchanger and primary accident tower, the position of secondary accident tower near top is equipped with lye pipeline, is connected chlorine gas ascending pipeline between primary accident tower and second accident tower, is connected with secondary sodium descending pipeline between secondary accident tower and secondary sodium circulating pipeline, the fresh lye is from secondary accident tower top and is entered, and the accident release chlorine gas or overpressure release chlorine gas is from primary accident tower bottom and is entered, realizes countercurrent absorption in series connection's primary accident tower and secondary accident tower.

Description

Technical Field

[0001] This utility model relates to the field of chlorine absorption technology, specifically a novel emergency chlorine absorption device. Background Technology

[0002] Production units using chlorine, such as chlor-alkali plants, must adopt a closed structure for liquid chlorine storage areas or loading and unloading areas, and install chlorine absorption devices. In the event of a chlorine leak in the workshop or plant, the chlorine absorption device will absorb and treat the collected leaked gas until it meets emission standards before being released. This will prevent major personnel poisoning incidents.

[0003] Chlorine absorption units typically consist of primary and secondary absorption towers connected in series, each equipped with a sodium hypochlorite circulation system. A 15-30% wt alkaline solution is usually used to absorb chlorine and react it to form a sodium hypochlorite solution. Once the sodium hypochlorite solution is saturated, it is pumped out for disposal.

[0004] Common chlorine absorption device processes include: Figure 1 As shown. The alkali solution is sourced from either gravity flow in an elevated tank or pump delivery from an alkali pool.

[0005] Chlorine absorption devices, as safety protection devices, do not directly generate economic benefits. Therefore, production units face problems such as large footprint (large number of devices), high equipment investment and backup (a large amount of chloride ions are present in the process system, considering corrosiveness), high overall energy consumption (easily generates a large amount of unsaturated sodium hypochlorite solution), and difficulty in personnel maintenance (chlorine ions can easily cause many leaks).

[0006] Some manufacturers have optimized their chlorine absorption units to use countercurrent absorption between primary and secondary absorption tower systems. The alkali solution enters only from the top of the secondary emergency tower, while emergency chlorine enters from the bottom of the primary absorption tower. This countercurrent absorption between the gas and liquid phases significantly reduces the amount of unsaturated sodium hypochlorite solution circulating between the systems. However, this approach still presents challenges such as large footprint (numerous equipment), high equipment investment and backup capacity (due to the presence of large amounts of chloride ions in the process system and their corrosiveness), and difficulty in personnel maintenance (chloride ions easily cause numerous leaks). Summary of the Invention

[0007] The purpose of this invention is to provide a novel chlorine gas absorption device for accidents, which solves the problems mentioned in the background art.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a novel emergency chlorine absorption device, comprising a primary emergency tower and a secondary emergency tower, wherein the secondary emergency tower is fixed above the primary emergency tower, an induced draft fan is connected above the secondary emergency tower, the primary emergency tower stores sodium hypochlorite solution inside, a chlorine gas venting pipeline is provided on the side of the primary emergency tower, a sodium hypochlorite circulation pump is provided at the bottom of the primary emergency tower and connected to the inlet of the sodium hypochlorite circulation pump, a sodium hypochlorite heat exchanger is connected to the outlet of the sodium hypochlorite circulation pump, a sodium hypochlorite circulation pipeline is connected between the sodium hypochlorite heat exchanger and the primary emergency tower, an alkali solution pipeline is provided near the top of the secondary emergency tower, a chlorine gas rising pipeline is connected between the primary and secondary emergency towers, and a sodium hypochlorite descending pipeline is connected between the secondary emergency tower and the sodium hypochlorite circulation pipeline. Fresh alkali solution enters from the top of the secondary emergency tower, while chlorine gas released during emergencies or overpressure releases enters from the bottom of the primary emergency tower. Countercurrent absorption is achieved within the series-connected primary and secondary emergency towers. During overpressure releases of chlorine gas in non-accident conditions, the circulating sodium hypochlorite solution only enters the primary emergency tower. This not only ensures that emergency chlorine gas is treated to the required standards but also effectively increases the concentration of the circulating sodium hypochlorite solution, reducing the amount of unsaturated sodium hypochlorite solution discharged. Separate primary and secondary chlorine gas circulation systems are no longer used; the circulating sodium hypochlorite solution is stored in the bottom of the primary emergency tower. Since the absorption reaction between chlorine and fresh alkali solution mainly occurs in the primary emergency tower, the sodium hypochlorite heat exchanger is optimized to a single unit, but the heat exchange area is considered to accommodate the total absorption reaction volume.

[0009] In a preferred embodiment of this invention, both the primary and secondary emergency towers are vertically arranged and fixed with a common cylindrical body. The primary and secondary emergency towers are vertically stacked using the common cylindrical body and supports, thus securing them.

[0010] As a preferred embodiment of this invention, the sodium circulation pipeline is equipped with a pH meter. When the pH meter reading is low, fresh alkali solution needs to be added to ensure complete chlorine absorption.

[0011] As a preferred embodiment of this invention, two chlorine gas release pipelines are provided, which are respectively used to receive chlorine gas released in case of an accident and chlorine gas released due to overpressure.

[0012] As a preferred embodiment of this invention, the sodium hypochlorite circulation pipe is connected to a sodium hypochlorite discharge pipe, which is used for discharging concentrated sodium hypochlorite solution.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] This invention connects a primary emergency tower and a secondary emergency tower in series. The alkali solution enters from the top of the secondary emergency tower, while the chlorine gas is released from the bottom of the primary emergency tower. Countercurrent absorption is achieved in the primary and secondary emergency towers connected in series. The circulating sodium hypochlorite solution generated in non-accident conditions only enters the primary emergency tower. This not only ensures that the chlorine gas in the accident is treated to meet the standards, but also reduces the amount of fresh alkali solution used to absorb the chlorine gas, and effectively reduces the amount of unsaturated sodium hypochlorite solution circulating in the process system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the existing chlorine absorption unit for an emergency tower.

[0016] Figure 2 This is a schematic diagram of the structure of this utility model.

[0017] In the diagram: 1. Primary emergency tower; 2. Secondary emergency tower; 3. Exhaust fan; 4. Chlorine gas venting pipeline; 5. Sodium hypochlorite circulation pump; 6. Sodium hypochlorite heat exchanger; 7. Sodium hypochlorite circulation pipeline; 8. Alkali solution pipeline; 9. Chlorine gas rising pipeline; 10. Sodium hypochlorite falling pipeline; 11. Sodium hypochlorite discharge pipeline; 12. Common cylinder. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] In the description of this utility model, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] Please see Figure 2This utility model provides a technical solution: a novel emergency chlorine absorption device, comprising a primary emergency tower 1 and a secondary emergency tower 2, wherein the secondary emergency tower 2 is fixed above the primary emergency tower 1, and an induced draft fan 3 is connected above the secondary emergency tower 2; the primary emergency tower 1 stores sodium hypochlorite solution inside, and a chlorine gas venting pipeline 4 is provided on the side of the primary emergency tower 1; a sodium hypochlorite circulation pump 5 is provided at the bottom of the primary emergency tower 1 and connected to the inlet of the sodium hypochlorite circulation pump 5; a sodium hypochlorite heat exchanger 6 is connected to the outlet of the sodium hypochlorite circulation pump 5; a sodium hypochlorite circulation pipe 7 is connected between the sodium hypochlorite heat exchanger 6 and the primary emergency tower 1; an alkali solution pipeline 8 is provided near the top of the secondary emergency tower 2; a chlorine gas rising pipe 9 is connected between the primary emergency tower 1 and the secondary emergency tower 2; and a sodium hypochlorite descending pipe 10 is connected between the secondary emergency tower 2 and the sodium hypochlorite circulation pipe 7. Fresh alkali solution enters from the top of the secondary emergency tower 2, while chlorine gas released during emergencies or overpressure releases enters from the bottom of the primary emergency tower 1. Countercurrent absorption is achieved within the series-connected primary and secondary emergency towers 2. During non-accident conditions, the circulating sodium hypochlorite solution generated from handling overpressure released chlorine gas only enters the primary emergency tower 1. This not only ensures that emergency chlorine gas is treated to the required standards but also effectively increases the concentration of the circulating sodium hypochlorite solution, reducing the amount of unsaturated sodium hypochlorite solution discharged. Separate primary and secondary chlorine gas circulation systems are no longer used; the circulating sodium hypochlorite solution is stored in the bottom of the primary emergency tower 1. Since the absorption reaction between chlorine gas and fresh alkali solution mainly occurs in the primary emergency tower 1, the sodium hypochlorite heat exchanger 6 is optimized to one unit, but the heat exchange area is considered to accommodate the total amount of absorption reaction.

[0022] Furthermore, both the primary emergency tower 1 and the secondary emergency tower 2 are vertically arranged and fixed with a common cylindrical body 12. The primary emergency tower 1 and the secondary emergency tower 2 are vertically stacked by using the common cylindrical body 12 and supports to fix the primary emergency tower 1 and the secondary emergency tower 2.

[0023] Furthermore, a pH meter is installed in the sodium circulation pipeline 7. When the pH meter reading is low, fresh alkali solution needs to be added to ensure complete chlorine absorption.

[0024] Furthermore, there are two chlorine gas release pipelines 4, which are used to receive chlorine gas released in case of an accident and chlorine gas released due to overpressure, respectively.

[0025] Furthermore, a sodium hypochlorite discharge pipe 11 is connected to the sodium hypochlorite circulation pipe 7, which is used for discharging concentrated sodium hypochlorite solution.

[0026] The optimized chlorine absorption unit for this accident consists mainly of a primary accident tower 1, a secondary accident tower 2, a sodium hypochlorite heat exchanger 6, and a sodium hypochlorite circulating pump 5. The primary accident tower 1 and the secondary accident tower 2 are supported by a shared cylinder 12. The sodium hypochlorite circulating pump 5 shares a foundation with both the primary and secondary accident towers 1 and 2 and is located nearby. The support and fixation of the sodium hypochlorite heat exchanger 6 can utilize the shared cylinder 12 of the primary and secondary accident towers 2. Due to the compact and concentrated layout, the support and fixation of related pipelines can also be considered on the shared cylinder 12 of the primary and secondary accident towers 1 and 2.

[0027] Furthermore, the alkaline solution and chlorine gas were absorbed in a countercurrent manner in the primary emergency tower 1 and the secondary emergency tower 2, resulting in a reduction in the amount of circulating sodium hydroxide solution produced by the system and an increase in its concentration, leading to a decrease in the diameter of the relevant pipelines.

[0028] The low concentration of sodium hypochlorite solution produced by the primary emergency tower 1 is used as the spray liquid in the primary emergency tower 1. After reacting to form a concentrated sodium hypochlorite solution in the primary emergency tower 1, a large amount of heat is released. After heat exchange by the sodium hypochlorite heat exchanger 6, the temperature is reduced and the absorption effect is improved.

[0029] In summary, the installation of Level 1 and Level 2 accident towers significantly reduces the footprint of the entire accident absorption system. Process optimization also reduces the number of devices, correspondingly lowers equipment investment, reduces overall energy consumption, and greatly reduces the frequency of personnel maintenance.

[0030] The pipelines and pipes in this device are equipped with valves for switching. The use of valves for switching is a mature existing technology, so it will not be described in detail here.

[0031] When no chlorine leak is detected in the enclosed plant, the emergency absorption system operates at low load, using the induced draft fan 3 to achieve low-frequency operation and meet production needs. Once the safety valve on the production unit trips, the overpressure chlorine gas is released into the primary emergency tower 1. At this time, the sodium hypochlorite solution is circulated in the primary emergency tower 1 by the sodium hypochlorite circulation pump 5 to ensure that the overpressure chlorine gas is discharged in compliance with standards.

[0032] When the toxic gas detector in the enclosed plant detects a chlorine concentration ≥1mg / m3, the emergency chlorine absorption system will be activated at full load, the fan and pump speeds will be turned up to maximum, and the alkaline pipeline 8 of the secondary emergency tower 2 will be fully opened. The chlorine will be fully absorbed through the primary emergency tower 1 and the secondary emergency tower 2 to ensure that the chlorine is absorbed to the standard before being discharged.

[0033] 15% liquid alkali comes from the high-level liquid alkali tank or the existing alkali pool via a transfer pump. It first enters the secondary emergency tower 2, where chlorine gas is released and sent to the primary emergency tower 1 via the chlorine gas release pipeline 4 by a blower. The chlorine gas and fresh alkali solution form a countercurrent absorption. The lean sodium hypochlorite solution generated in the secondary emergency tower 2 enters the primary emergency tower 1 through the sodium hypochlorite downcomer pipeline 10. It is sprayed to absorb the chlorine gas released in case of an emergency or overpressure. The concentrated sodium hypochlorite solution generated in the reaction is pressurized by the sodium hypochlorite circulation pump 5 and enters the sodium hypochlorite heat exchanger 6. After being cooled by circulating water, it enters the primary emergency tower 1. After multiple cycles of absorption to saturation, it is discharged through the sodium hypochlorite circulation pump 5.

[0034] Taking a venting gas handling capacity of 10,000 Nm3 / h as an example, the specific configuration of the new emergency chlorine absorption device in this unit is as follows:

[0035] The equipment specifications of the Level 1 emergency tower are DN1600 / 2000×10000mm. The equipment material is carbon steel lined with vinyl resin. The internal parts are new Pall rings of 50x50x1.5 to reduce the height of the packing section.

[0036] The secondary emergency tower has a specification of DN1600×8000mm, is made of fiberglass lined with vinyl ester resin, and uses new 50x50x1.5 Pall rings for internal components to reduce the height of the packing section.

[0037] The sodium hypochlorite heat exchanger is a plate heat exchanger, 60㎡, made of titanium.

[0038] The sodium circulation pump has a specification of Q=67m3 and H=45m, and the material is carbon steel lined with PTFE.

[0039] The specifications of the emergency fan are Q=10000Nm3 / h, and the material of the equipment is FRP.

[0040] After optimization, the total footprint does not exceed 5 square meters, the number of equipment is greatly reduced, the length of related process pipelines is greatly reduced, and the pipe diameter is also reduced. Under the premise of ensuring that chlorine emissions meet standards in case of accidents, equipment investment is reduced accordingly, overall energy consumption is reduced, and the frequency of personnel maintenance is greatly reduced.

[0041] It is worth noting that the entire device is controlled by a master control button. Since the device matched with the control button is a common device and belongs to existing mature technology, its electrical connection relationship and specific circuit structure will not be described in detail here.

[0042] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel chlorine gas absorption device for accidents, characterized in that: The system includes a primary emergency tower (1) and a secondary emergency tower (2). The secondary emergency tower (2) is fixed above the primary emergency tower (1). An induced draft fan (3) is connected above the secondary emergency tower (2). The primary emergency tower (1) stores sodium hypochlorite solution. A chlorine gas venting pipeline (4) is installed on the side of the primary emergency tower (1). A sodium hypochlorite circulation pump (5) is installed at the bottom of the primary emergency tower (1) and connected to the inlet of the sodium hypochlorite circulation pump (5). A sodium hypochlorite heat exchanger (6) is connected to the outlet of the sodium hypochlorite circulation pump (5). A sodium hypochlorite circulation pipe (7) is connected between the sodium hypochlorite heat exchanger (6) and the primary emergency tower (1). An alkali solution pipeline (8) is installed near the top of the secondary emergency tower (2). A chlorine gas rising pipeline (9) is connected between the primary emergency tower (1) and the secondary emergency tower (2). A sodium hypochlorite descending pipeline (10) is connected between the secondary emergency tower (2) and the sodium hypochlorite circulation pipe (7).

2. The novel emergency chlorine absorption device according to claim 1, characterized in that: Both the primary emergency tower (1) and the secondary emergency tower (2) are vertically arranged and fixed with a common cylinder (12).

3. The novel emergency chlorine absorption device according to claim 1, characterized in that: A pH meter is installed inside the secondary sodium circulation pipeline (7).

4. The novel emergency chlorine gas absorption device according to claim 1, characterized in that: There are two chlorine gas release pipelines (4), which are used to receive chlorine gas released in case of an accident and chlorine gas released under overpressure, respectively.

5. A novel emergency chlorine gas absorption device according to claim 1, characterized in that: The sodium circulation pipe (7) is connected to the sodium discharge pipe (11).

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