Detachable anti-material-accumulation dry purification boiling device and electrolytic flue gas dry purification method based on detachable anti-material-accumulation dry purification boiling device

Abstract

The invention provides a detachable anti-accumulation dry purification boiling device and an electrolytic flue gas dry purification method based on the same, a gas chamber of the boiling device is divided into a left gas chamber and a right gas chamber which are symmetrical, the sections of the two gas chambers are semi-arc-shaped on the inner side and square on the outer side, and the two gas chambers are provided with gasification gas inlet holes and gas inlet valves corresponding to the gasification gas inlet holes; a gasification plate is correspondingly arranged in each of the left gas chamber and the right gas chamber, the shape of the gasification plate is matched with the section of the corresponding gas chamber, and the gasification plate is arranged to form a certain inclined angle with the horizontal plane; the gasification plate is detachably fixed in the gas chamber through the locking flange and the gasification locking counter flange; a plurality of quick-opening holes are formed in the side part of the air chamber of the boiling device, so that base slag at the bottom can be cleaned in time. The air chamber of the boiling device is designed to be divided into chambers, so that the boiling device is convenient to mount and dismount, the problems that accumulated slag at the bottom of the boiling device cannot be cleaned, a boiling plate is blocked, and fluorine-loaded aluminum oxide is unsmooth to convey are thoroughly solved, and the safety and reliability of equipment operation are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial electrolytic flue gas treatment, and in particular relates to a detachable anti-accumulation material dry purification boiling device and an electrolytic flue gas dry purification method based thereon. Background Art

[0002] Industrial aluminum electrolysis cells use fluoride salt-alumina melt as electrolyte and carbon materials as electrodes for electrolysis. Liquid aluminum metal is precipitated on the cathode, and anode gas mainly composed of CO2 is produced on the anode. At the same time, flue gas mainly composed of atmospheric pollutants such as fluoride, dust, and sulfur dioxide is also emitted, which is collectively referred to as electrolytic flue gas with anode gas. The main harmful components in electrolytic flue gas are fluoride, dust and sulfur dioxide.

[0003] In accordance with the requirements of the national environmental protection standards "Aluminum Industry Pollutant Emission Standard" (GB25465-2010), "Aluminum Industry Pollutant Emission Standard" (GB25465-2010) Amendment (2013), "Occupational Exposure Limits for Hazardous Factors in Industrial Workplaces" (GBZ2-2007) and "Aluminum Industry Standard Conditions" (revised in 2013) issued by the Ministry of Industry and Information Technology, it is necessary to efficiently collect the flue gas emitted by the electrolytic cell, improve the working environment of the electrolytic workshop, and centrally manage the electrolytic flue gas to recover the harmful components so that the flue gas can be discharged in compliance with the standards.

[0004] For the recovery of fluoride in electrolytic flue gas, alumina dry adsorption purification recovery is usually adopted. Its basic principle is to complete it through the principle of adsorption reaction. Adsorption is a surface effect. The larger the specific surface area of ​​the adsorbent, the stronger its adsorption capacity. The higher the boiling point of the adsorbate, the easier it is to be adsorbed, and vice versa. Adsorption is generally divided into physical adsorption and chemical adsorption.

[0005] Al2O3 has a high porosity, a large specific surface area, and is an amphoteric compound. It has good adsorption for acidic gases and asphalt volatiles. Experiments have shown that Al2O3 adsorbs HF mainly by chemical adsorption, followed by physical adsorption. The result of chemical adsorption is that on the surface of Al2O3, each Al2O3 molecule adsorbs two HF molecules to form a monolayer adsorption compound.

[0006] For physical adsorption, the boiling point of the adsorbate is of decisive significance. For chemical adsorption, in addition to the boiling point, the reactivity of the adsorbent and the adsorbate is also extremely important. HF has the characteristics of high boiling point, strong chemical activity, and is easily adsorbed by Al2O3.

[0007] Although the dry adsorption purification and recovery technology in the electrolytic aluminum industry is relatively mature, there are many problems in the actual operation process and poor adaptability, especially when dealing with large flue gas volumes in 600KA electrolytic cells, the problems are more prominent, and the most critical ones are the defluorination reactor and boiling device. For the vertical radial multi-point reactor, the dry purification dust collector with the bottom air intake of the dust collector hopper is just a simple expansion of the boiling device. There are the following main problems:

[0008] 1) The limited site space will inevitably increase the diameter of a single reactor, and the corresponding boiling device must also be enlarged, resulting in uneven flow field distribution, poor alumina distribution, and uneven fluidizing air distribution in the boiling device;

[0009] 2) The boiling device has no slope. For boiling devices with large cross-sections, its fluidity is poor, and the adsorbed alumina is not discharged to the overflow port, resulting in an increase in alumina in the boiling bed, and alumina runs to the reactor inlet flue, causing the inlet flue to be blocked by accumulation of materials;

[0010] 3) The slag at the bottom of the boiling device with a large cross-section cannot be cleaned, blocking the boiling plate, making the alumina unable to boil, causing the alumina to break, block and stagnate, and form agglomerates;

[0011] 4) The boiling device with a large cross-section is a whole boiling gasification plate. If the boiling gasification plate is broken, it cannot be replaced. In addition, the positioning of the bolt holes of the boiling gasification plate cannot be guaranteed during installation, and the boiling gasification plate cannot be tightened, making installation difficult.

[0012] Therefore, how to achieve uniform distribution of alumina and fluidizing air in a large-diameter boiling device, as well as convenient maintenance and disassembly of the boiling gasification plate, is a problem that needs to be solved. Summary of the invention

[0013] In view of the problems existing in the prior art, the object of the present invention is to provide a detachable anti-deposit material dry purification boiling device and an electrolytic flue gas dry purification method based thereon.

[0014] The objective of the present invention is achieved through the following technical solutions:

[0015] The first aspect of the present invention provides a detachable anti-accumulation material dry purification boiling device, which is arranged at the connection between the dust collector ash hopper and the flue gas reactor (specifically at the connection between the ash hopper and the upper part of the reactor); ensuring the flow state of the material at the bottom of the ash hopper, wherein the boiling device includes a boiling device air chamber, a gasification plate, a quick opening hole and a gasification air inlet hole;

[0016] The boiling device air chamber is divided into two symmetrical air chambers, left and right, the cross-sections of the two air chambers are semicircular arc inside and square outside, and both air chambers are provided with gasification air inlet holes and corresponding air inlet valves;

[0017] A gasification plate is provided in each of the left and right air chambers, the shape of the gasification plate matches the cross section of the corresponding air chamber, and the gasification plate is arranged to have a certain inclination angle with the horizontal plane; the gasification plate is detachably fixed in the air chamber by a locking flange and a gasification locking counter flange;

[0018] A plurality of quick-opening holes are arranged on the side of the air chamber of the boiling device to realize timely cleaning of the bottom slag.

[0019] Furthermore, the inclination angle between the gasification plate and the horizontal plane is not less than 3°.

[0020] Furthermore, the number of the quick opening holes is n, where n≥2.

[0021] Furthermore, a baffle is provided above the gasification air inlet hole.

[0022] The second aspect of the present invention provides a method for dry purification of electrolytic flue gas using the boiling device of the first aspect, comprising the following steps:

[0023] The electrolytic flue gas to be treated enters the flue gas reaction device vertically upward through the air inlet flue. In the flue gas reaction device, the hydrogen fluoride gas (HF) in the electrolytic flue gas undergoes a chemical reaction and adsorption reaction with alumina (AL2O3), turning the hydrogen fluoride gas into a solid form - fluorine-carrying alumina;

[0024] The fluorine-loaded aluminum oxide falls into the detachable anti-accumulation material dry purification boiling device of the first aspect at the bottom of the flue gas reaction device:

[0025] First, by controlling the air inlet valves on the two air chambers, the air sent by the high-pressure centrifugal fan is sent into the air chamber of the boiling device through the gasification air inlet hole. The air evenly penetrates the gasification plate in the air chamber, so that the fluorine-loaded alumina on the upper part of the gasification plate boils evenly.

[0026] Since the gasification plate is set at a certain inclination angle with the horizontal plane, the fluorine-carrying aluminum oxide on the gasification plate flows to the return material connection port for recycling;

[0027] Secondly, after running for a certain period of time, the quick opening hole is opened regularly to clean the base slag at the bottom of the gasification plate, so as to ensure that the fluorine-carrying alumina on the gasification plate flows to the return material connection port for recycling;

[0028] Finally, when the gasification plate is damaged or needs to be replaced, the gasification plates in the left and right air chambers are replaced simultaneously or separately by disassembling the locking flange and the gasification locking counter-flange.

[0029] Furthermore, the harmful components in the electrolytic flue gas include fluoride, dust and sulfur dioxide.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The existing boiling device has a large air chamber, which is difficult to disassemble and maintain. The dry purification boiling device described in this patent realizes the convenience of installation and disassembly of the boiling device by designing the air chamber of the boiling device in a chamber, and completely solves the problems of the slag accumulation at the bottom of the boiling device that cannot be cleaned, the boiling plate is blocked, and the fluorine-carrying alumina is not smoothly transported, thereby improving the safety and reliability of the equipment operation;

[0032] 2. In the dry purification boiling device described in this patent, the vaporization plate is set at a certain inclination angle with the horizontal plane, which can solve the problem that the fluorine-carrying alumina in the boiling device with a large cross-section cannot flow, and at the same time avoid the situation where the fluorine-carrying alumina in the boiling device increases and runs to the inlet flue;

[0033] 3. In the dry purification boiling device described in this patent, by setting a number of quick opening holes on the side of the air chamber of the boiling device, it is convenient to clean the accumulated slag at the bottom and avoid the boiling of the boiling bed due to compaction and agglomeration. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0035] Figure 1 It is a structural schematic diagram of an existing boiling device;

[0036] Figure 2 This is a schematic structural diagram of a detachable anti-accumulation material dry purification boiling device according to an embodiment of the present application;

[0037] Figure 3 for Figure 2 Schematic side view of the middle AA section;

[0038] Figure 4 for Figure 2 Schematic diagram of the top view of the BB section.

[0039] Among them, the arrow indicates the flow direction of the electrolytic flue gas; 1-boiling device air chamber, 2-gasification plate, 3-locking flange, 4-quick opening, 5-gasification air inlet, 501-baffle, 6-air inlet duct, 7-gasification locking counter flange. DETAILED DESCRIPTION

[0040] It should be noted that the features in the following patent descriptions can be combined with each other without conflict; all other patents obtained by technical personnel in this field without creative work are within the scope of protection of this patent.

[0041] It should be noted that various aspects within the scope of the appended claims are described below. It should be apparent that the various aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the various aspects described herein can be used to implement this device and / or practice this method.

[0042] Example 1

[0043] like Figure 2-Figure 4 As shown, this embodiment provides a detachable anti-accumulation material dry purification boiling device, which is arranged at the bottom of the flue gas reaction device, wherein the boiling device includes a boiling device air chamber 1, a gasification plate 2, a quick opening hole 4 and a gasification air inlet hole 5.

[0044] The boiling device air chamber 1 is divided into two symmetrical air chambers on the left and right. The cross-sections of the two air chambers are semicircular on the inner side and square on the outer side. Both air chambers are provided with gasification air inlet holes 5 and corresponding air inlet valves, so as to realize independent air intake of the two air chambers. Not only can the entire air chamber be directly disassembled from the bottom of the boiling device, but each air chamber can also adjust the air intake volume by switching the size of the air inlet valve according to the ash storage amount in the ash hopper gasification plate.

[0045] In order to avoid direct scouring of the gasification plate by air and extend the service life of the gasification plate, a baffle 501 is provided above the gasification air inlet hole so that the air entering the air chamber of the boiling device is diverted by the baffle.

[0046] A gasification plate 2 is respectively arranged in the left and right air chambers. The shape of the gasification plate matches the cross section of the corresponding air chamber, and the gasification plate is arranged to have a certain inclination angle with the horizontal plane. The gasification plate is detachably fixed in the air chamber by a locking flange and a gasification locking counter flange.

[0047] A plurality of quick-opening holes are arranged on the side of the air chamber of the boiling device to realize timely cleaning of the bottom slag.

[0048] In order to ensure that the ash in the gasification plate can flow naturally driven by the boiling gas, the inclination angle of the gasification plate to the horizontal plane is not less than 3°.

[0049] In this embodiment, according to the actual size of the air chamber of the boiling device, the number of the quick opening holes is 2, and its purpose is to be able to manually clean the slag accumulated at the bottom of the boiling bed regularly.

[0050] The electrolytic flue gas dry purification method using the boiling device comprises the following steps:

[0051] The electrolytic flue gas to be treated (the harmful components are mainly fluoride, dust and sulfur dioxide) enters the flue gas reaction device vertically upward through the air inlet flue 6. In the flue gas reaction device, the hydrogen fluoride gas (HF) in the electrolytic flue gas reacts chemically and adsorbs with alumina (AL2O3), so that the hydrogen fluoride gas is converted into a solid form - fluorine-carrying alumina;

[0052] The fluorine-loaded aluminum oxide falls into the detachable anti-accumulation material dry purification boiling device of the first aspect at the bottom of the flue gas reaction device:

[0053] First, by controlling the air inlet valves on the two air chambers, the air sent by the high-pressure centrifugal fan is sent into the air chamber of the boiling device through the gasification air inlet hole. The air evenly penetrates the gasification plate in the air chamber, so that the fluorine-loaded alumina on the upper part of the gasification plate boils evenly.

[0054] Since the gasification plate is set at a certain inclination angle with the horizontal plane, the fluorine-carrying aluminum oxide on the gasification plate flows to the return material connection port for recycling;

[0055] Secondly, after running for a certain period of time, the quick opening hole is opened regularly to clean the base slag at the bottom of the gasification plate, so as to ensure that the fluorine-carrying alumina on the gasification plate flows to the return material connection port for recycling;

[0056] Ensure that the fluorine-loaded alumina does not accumulate on the gasification plate, and at the same time reduce the continuous wear of the fluorine-loaded alumina to form floating ash that is not conducive to sedimentation, which causes the system return material to be discharged unsmoothly.

[0057] Finally, after 3 to 5 years of use, when the vaporizer plate is damaged or needs to be replaced, the vaporizer plates in the left and right air chambers are replaced simultaneously or separately by disassembling the locking flange and the vaporizer locking counter flange.

[0058] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement scheme, a person skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A detachable anti-accumulation material dry purification boiling device, which is arranged at the connection between the dust collector ash hopper and the flue gas reaction device, characterized in that: The boiling device comprises a boiling device air chamber (1), a vaporization plate (2), a quick opening hole (4) and a vaporization air inlet hole (5); The boiling device air chamber (1) is divided into two symmetrical air chambers, left and right, the cross-sections of the two air chambers are both semicircular arc-shaped on the inside and square on the outside, and both air chambers are provided with gasification air inlet holes (5) and corresponding air inlet valves; A gasification plate (2) is respectively arranged in the left and right air chambers, the shape of the gasification plate (2) matches the cross section of the corresponding air chamber, and the gasification plate is arranged to have a certain inclination angle with the horizontal plane; the gasification plate is detachably fixed in the air chamber by means of a locking flange (3) and a gasification locking counter flange (7); A plurality of quick-opening holes (4) are arranged on the side of the gas chamber of the boiling device to realize timely cleaning of the bottom slag.

2. The boiling device according to claim 1, characterized in that The inclination angle between the gasification plate (2) and the horizontal plane is not less than 3°.

3. The boiling device according to claim 1, characterized in that: The number of the quick opening holes (4) is n, where n≥2.

4. The boiling device according to claim 1, characterized in that: A baffle (501) is provided above the gasification air inlet hole (5).

5. A method for dry purification of electrolytic flue gas based on the boiling device according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: The electrolytic flue gas to be treated enters the flue gas reaction device vertically upward through the gas inlet duct (6). In the flue gas reaction device, the hydrogen fluoride gas (HF) in the electrolytic flue gas undergoes a chemical reaction and an adsorption reaction with alumina (AL2O3), so that the hydrogen fluoride gas is converted into a solid form - fluorine-carrying alumina; The fluorine-loaded aluminum oxide falls into the bottom of the flue gas reaction device in the detachable anti-accumulation material dry purification boiling device as claimed in any one of claims 1 to 4: First, by controlling the air inlet valves on the two air chambers, the air sent by the high-pressure centrifugal fan is sent into the air chamber (1) of the boiling device through the gasification air inlet hole (5), and the air evenly penetrates the gasification plate (2) in the air chamber, so that the fluorine-carrying aluminum oxide on the upper part of the gasification plate is evenly boiled; Since the gasification plate is set at a certain inclination angle with the horizontal plane, the fluorine-carrying aluminum oxide on the gasification plate flows to the return material connection port for recycling; Secondly, after a certain period of operation, the quick opening hole (4) is opened regularly to clean the slag at the bottom of the gasification plate, thereby ensuring that the fluorine-carrying alumina on the gasification plate flows to the return material connection port for recycling; Finally, when the gasification plate is damaged or needs to be replaced, the gasification plates in the left and right gas chambers are replaced simultaneously or separately by disassembling the locking flange (3) and the gasification locking counter flange (7).

6. The electrolytic flue gas dry purification method according to claim 5, characterized in that: The harmful components in the electrolytic flue gas include fluoride, dust and sulfur dioxide.

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