Voc collection and storage device for by-products of hydrochloric acid based on chlorinated benzene production

Abstract

This utility model discloses a VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, relating to the field of chlorobenzene production technology. The device includes a sealed storage tank with a hydrochloric acid inlet / outlet on one side of the tank's bottom for introducing and discharging hydrochloric acid. The tank's interior is fitted with a wax seal structure that conforms to the tank's inner wall and is movable up and down along the tank, positioned above the hydrochloric acid inlet / outlet. A one-way valve is located at the top of the tank, connecting to the interior and allowing gas to escape only from the inside. A pressure balancing mechanism is also installed at the top of the tank to introduce inert gas to balance the internal pressure.

Description

Technical Field

[0001] This utility model relates to the field of chlorobenzene production technology, specifically to a VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production. Background Technology

[0002] Volatile organic compounds (VOCs) are a class of organic compounds that are easily volatilized at room temperature and are widely present in the environment and industrial production. The release of large amounts of VOCs has had a significant negative impact on the environment, including air pollution and photochemical ozone formation, and also significantly endangers human health.

[0003] In the production of chlorobenzene, a large amount of chlorobenzene, hydrogen chloride, and unreacted benzene are generated during the chlorination process and escape from the top of the reactor. After a spray absorption process, the hydrogen chloride gas carries some benzene and chlorobenzene to form hydrochloric acid, a byproduct, which is stored in a hydrochloric acid storage tank. Because VOCs such as benzene and chlorobenzene volatilize during the storage of the byproduct hydrochloric acid, they are highly flammable and explosive. To prevent benzene and chlorobenzene from accumulating to the explosive limit, the hydrochloric acid storage tank is currently an open, atmospheric pressure tank with a wax seal. This type of tank results in fugitive emissions of waste gas, without effective collection and treatment of VOCs. Therefore, the applicant recognizes that in order to meet environmental protection requirements and reduce VOC hazards, it is urgent to solve the problem of fugitive emissions of waste gas. Utility Model Content

[0004] Therefore, this utility model provides a VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, to solve the problems existing in the above-mentioned technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, is characterized by comprising a sealed storage tank, wherein a hydrochloric acid inlet and outlet are provided at the bottom of one side of the storage tank for introducing and discharging hydrochloric acid, and a wax sealing structure is provided inside the storage tank, wherein the wax sealing structure is fitted to the inner wall of the storage tank, the wax sealing structure is movable up and down along the storage tank, and the wax sealing structure is positioned above the hydrochloric acid inlet and outlet.

[0007] The top of the storage tank is equipped with a one-way valve, which connects to the inside of the storage tank, so that the gas inside the storage tank can only be discharged from the inside to the outside.

[0008] The top of the storage tank is also equipped with a pressure balancing mechanism, which is used to fill the storage tank with inert gas to balance the internal pressure.

[0009] Optionally, the wax seal structure is a disc-shaped structure adapted to the cross-sectional shape of the storage tank, and the wax seal structure is fitted to the side wall of the storage tank.

[0010] The storage tank has a support member located on the inner wall near the hydrochloric acid inlet and outlet. There are at least two support members, which are used to support the wax seal structure.

[0011] Optionally, the wax seal structure is made of paraffin wax or natural wax.

[0012] Optionally, four supports are provided, and the four supports are distributed in a circumferential array around the storage tank.

[0013] Optionally, the one-way valve is a one-way breather valve.

[0014] Optionally, the inert gas is nitrogen.

[0015] Optionally, the pressure balancing mechanism includes a nitrogen generator, an inflation pipeline, and an automatic pressure reducing valve. The nitrogen outlet of the nitrogen generator is connected to the inflation pipeline, the inflation pipeline is connected to the top of the storage tank, and the automatic pressure reducing valve is located on the inflation pipeline.

[0016] The storage tank is equipped with a pressure sensor, which is electrically connected to an automatic pressure reducing valve.

[0017] Optionally, the top of the storage tank is configured as a conical structure that is smaller at the top and larger at the bottom, and the one-way valve is located at the top of the conical structure of the storage tank.

[0018] This utility model has at least the following beneficial effects:

[0019] This invention utilizes a wax-sealing structure installed inside the storage tank. This structure floats above the hydrochloric acid solution when it is introduced, reducing the volatilization of the hydrochloric acid and any entrained benzene and chlorobenzene. Even if volatilization occurs, it can be discharged through a one-way valve at the top of the tank, maintaining a suitable pressure within the tank. When hydrochloric acid is discharged from the inlet and outlet, a negative pressure environment is created inside the tank. At this time, an inert gas is introduced into the tank through a pressure balancing device to maintain a slight negative pressure, preventing air from entering the tank and reacting with benzene and chlorobenzene to cause an explosion. This also avoids problems such as overpressure, rupture, or negative pressure collapse. Attached Figure Description

[0020] To more clearly illustrate the prior art and the present invention, the accompanying drawings used in the description of the prior art and the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other drawings from the provided drawings without any creative effort.

[0021] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which this utility model can be implemented. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0022] Figure 1 This is a schematic diagram of the principle structure of one embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Storage tank; 2. Hydrochloric acid inlet and outlet; 3. Wax seal structure; 4. Check valve; 5. Pressure balancing mechanism; 51. Nitrogen generator; 52. Gas filling pipeline; 53. Automatic pressure reducing valve; 6. Support components. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] In the description of this utility model, unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," "fourth," etc. (if present), in the specification, claims, and accompanying drawings of this utility model are intended to distinguish the objects they refer to. For solutions with a sequential flow, this terminology need not be interpreted as describing a specific order or sequence; for solutions with device structures, this terminology does not distinguish between matters of importance or positional relationships.

[0027] Furthermore, the terms “comprising,” “having,” and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are expressly listed, but may also include other steps or units that are not expressly listed but are inherent to these processes, methods, products, or devices, or steps or units added based on further optimizations of the inventive concept.

[0028] like Figure 1 As shown, this utility model discloses a VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production. It includes a sealed storage tank 1. The bottom of one side of the storage tank 1 is provided with a hydrochloric acid inlet and outlet 2 for introducing and discharging hydrochloric acid. The storage tank 1 is provided with a wax sealing structure 3 inside. The wax sealing structure 3 is fitted to the inner wall of the storage tank 1 and can move up and down along the storage tank 1. The wax sealing structure 3 is located above the hydrochloric acid inlet and outlet 2.

[0029] The top of the storage tank 1 is equipped with a one-way valve 4, which connects to the inside of the storage tank 1, so that the gas inside the storage tank 1 can only be discharged from the inside to the outside.

[0030] The top of the storage tank 1 is also provided with a pressure balancing mechanism 5, which is used to fill the storage tank 1 with inert gas to balance the internal pressure of the storage tank 1.

[0031] The aforementioned storage tank 1 can be made of the same material as the existing hydrochloric acid storage tank, and its shape is set as a cylindrical or cuboid structure, generally set as a cylindrical structure. The bottom of the outer side of the storage tank 1 is provided with hydrochloric acid inlet and outlet 2, which is used to connect to the chlorobenzene production device, and to pass the hydrochloric acid, a by-product of the production process, into the storage tank 1. At the same time, the hydrochloric acid solution will also contain volatile benzene and chlorobenzene.

[0032] The storage tank 1 is equipped with a wax sealing structure 3. The wax sealing structure 3 uses the buoyancy of the hydrochloric acid solution to float above the hydrochloric acid solution. At the same time, it floats up and down according to the liquid level of the hydrochloric acid solution. The setting of the wax sealing structure 3 can reduce the volatilization of hydrochloric acid, benzene and chlorobenzene. At the same time, the wax sealing structure 3 fits the tank wall of the storage tank 1 as closely as possible without affecting the up and down floating.

[0033] In addition, to prevent the wax seal structure 3 from falling off, a support 6 is installed on the inner wall of the storage tank 1 at a position 21-2cm above the hydrochloric acid inlet and outlet to support the wax seal structure 3 when there is no hydrochloric acid in the storage tank 1.

[0034] The aforementioned one-way valve 4 is installed at the top of the storage tank 1, which can discharge the volatile gas from the storage tank 1 when hydrochloric acid solution, benzene and chlorobenzene evaporate, thus avoiding overpressure and explosion.

[0035] The gas pressure balance structure can prevent air absorption when a negative pressure is formed inside the storage tank 1 during the discharge of hydrochloric acid. Inert gas can be introduced into the storage tank 1 through the gas pressure balance mechanism 5 to prevent explosion, while maintaining a slightly negative pressure environment inside the storage tank 1.

[0036] In one specific embodiment, the wax sealing structure 3 is a disc-shaped structure adapted to the cross-sectional shape of the storage tank 1, and the wax sealing structure 3 is fitted to the side wall of the storage tank 1.

[0037] A support member 6 is provided on the inner wall of the storage tank 1 near the hydrochloric acid inlet / outlet 2. At least two support members 6 are provided to support the wax seal structure 3.

[0038] The wax seal structure 3 mentioned above is made of paraffin wax or natural wax and is designed to fit the shape of the storage tank 1. Paraffin wax is generally used because it is low in cost, has good sealing performance, and is easy to process.

[0039] In a further embodiment, four support members 6 are provided, and the four support members 6 are distributed in a circumferential array around the storage tank 1.

[0040] The support member 6 is set to four, which support the wax sealing structure 3 from multiple directions, ensuring the stability of the support and preventing the wax sealing structure 3 from tilting and getting stuck on the can wall.

[0041] In one specific embodiment, in order to facilitate the discharge of volatile gases from storage tank 1, the one-way valve 4 is a one-way breather valve.

[0042] To prevent air from being drawn into storage tank 1, the inert gas is nitrogen. Nitrogen is relatively inexpensive.

[0043] Specifically, the pressure balancing mechanism 5 includes a nitrogen generator 51, an inflation line 52, and an automatic pressure reducing valve 53. The nitrogen outlet of the nitrogen generator 51 is connected to the inflation line 52, the inflation line 52 is connected to the top of the storage tank 1, and the automatic pressure reducing valve 53 is installed on the inflation line 52.

[0044] A pressure sensor is installed inside the storage tank 1, and the pressure sensor is electrically connected to the automatic pressure reducing valve 53.

[0045] By setting a nitrogen generator 51 as a nitrogen source, and connecting it to the inside of the storage tank 1 through the gas filling pipe 52, nitrogen is filled into the storage tank 1 through the gas outlet pipe when gas filling is required.

[0046] To determine whether nitrogen needs to be added, a pressure sensor installed in storage tank 1 is used. When some hydrochloric acid is discharged, a negative pressure is formed in storage tank 1. When the pressure reaches the preset value of the pressure sensor, the control system transmits a control signal to the automatic pressure reducing valve 53 to open, and nitrogen is added into storage tank 1. When the pressure in storage tank 1 reaches the preset micro-negative pressure state, the automatic pressure reducing valve 53 is closed to stop adding nitrogen.

[0047] The nitrogen generator 51 mentioned above can adopt a commercially available structure, the specific structure of which will not be described in detail here.

[0048] It should be noted that the above-described method of detecting the pressure of storage tank 1 and feeding back control signals to automatic pressure reducing valve 53 is existing technology and will not be elaborated here.

[0049] In a further embodiment, the top of the storage tank 1 is configured as a conical structure that is smaller at the top and larger at the bottom, and the one-way valve 4 is disposed at the top of the conical structure of the storage tank 1.

[0050] By setting the top of storage tank 1 into a conical structure, it is easier to discharge gas.

[0051] The hydrochloric acid storage tank, a byproduct of the production of dichlorobenzene, is a closed tank structure. The hydrochloric acid storage tank has a sealed structure, is equipped with an automatic nitrogen sealing valve and a single exhalation valve, and has a paraffin float inside.

[0052] The paraffin floating plate is in full contact with the liquid level in the tank, effectively reducing the amount of organic matter volatilization;

[0053] In the gas phase space between the upper part of the floating roof and the top of the tank, the single exhale valve and the air pressure balancing mechanism 5 work together to maintain the space in a slightly negative pressure state, preventing air from entering the tank and reacting with benzene and chlorobenzene to cause an explosion. It can also avoid problems such as overpressure, rupture or negative pressure collapse, and ensure the safety of the storage tank.

[0054] The above specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0055] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

[0056] The present invention has been described in a relatively specific and detailed manner above through general description and specific embodiments. It should be noted that, without departing from the concept of the present invention, various modifications and improvements can be made to these specific embodiments, all of which fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, characterized in that: The storage tank includes a sealed container. The bottom of one side of the storage tank is provided with a hydrochloric acid inlet and outlet for introducing and discharging hydrochloric acid. The storage tank is provided with a wax sealing structure inside. The wax sealing structure is fitted to the inner wall of the storage tank and can move up and down along the storage tank. The wax sealing structure is located above the hydrochloric acid inlet and outlet. The top of the storage tank is equipped with a one-way valve, which connects to the inside of the storage tank, so that the gas inside the storage tank can only be discharged from the inside to the outside. The top of the storage tank is also equipped with a pressure balancing mechanism, which is used to fill the storage tank with inert gas to balance the internal pressure.

2. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, as described in claim 1, is characterized in that: The wax seal structure is a disc-shaped structure adapted to the cross-sectional shape of the storage tank, and the wax seal structure is fitted to the side wall of the storage tank. The storage tank has a support member located on the inner wall near the hydrochloric acid inlet and outlet. There are at least two support members, which are used to support the wax seal structure.

3. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, as described in claim 1, is characterized in that: The wax seal structure is made of paraffin wax or natural wax.

4. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, according to claim 2, is characterized in that: The support is provided in four parts, and the four support members are distributed in a circular array around the storage tank.

5. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, according to claim 1, is characterized in that: The one-way valve is a one-way breather valve.

6. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, according to claim 1, is characterized in that: The inert gas is nitrogen.

7. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, according to claim 1, is characterized in that: The pressure balancing mechanism includes a nitrogen generator, an inflation pipeline, and an automatic pressure reducing valve. The nitrogen outlet of the nitrogen generator is connected to the inflation pipeline, the inflation pipeline is connected to the top of the storage tank, and the automatic pressure reducing valve is located on the inflation pipeline. The storage tank is equipped with a pressure sensor, which is electrically connected to an automatic pressure reducing valve.

8. The VOCs collection and storage device for hydrochloric acid, a byproduct of chlorobenzene production, according to claim 1, is characterized in that: The top of the storage tank is configured as a conical structure that is smaller at the top and larger at the bottom, and the one-way valve is located at the top of the conical structure of the storage tank.

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