A hot air circulating arsenic removal system and method

Abstract

This invention provides a hot air circulation arsenic removal system and method. The system includes: an arsenic removal group comprising multiple arsenic removal furnaces; in one sub-cycle, the multiple arsenic removal furnaces respectively have loading / unloading, drying, reduction, sublimation, and cooling operating states; each arsenic removal furnace can only be in one operating state in one sub-cycle; a drying group connected to the arsenic removal group for providing a first hot air to the arsenic removal group; a hot air group connected to the arsenic removal group for providing a second hot air to the arsenic removal group; and a flue gas treatment group connected to the arsenic removal group for receiving and treating the flue gas from the arsenic removal group. This application utilizes hot air circulation to sublimate arsenic and remove it from the brick stack in the form of waste gas, thereby achieving arsenic removal; multiple arsenic removal furnaces share the drying group, hot air group, and flue gas treatment group, and the operating states of the multiple arsenic removal furnaces are rationally allocated in one sub-cycle, so that the production needs of multiple arsenic removal furnaces can be met with a limited number of drying groups, hot air groups, and flue gas treatment groups, thus reducing costs.

Description

Technical Field

[0001] This invention belongs to the technical field of arsenic removal from materials, specifically relating to a hot air circulating arsenic removal system and method. Background Technology

[0002] Due to the nature of the production materials, some brick stacks currently in production require arsenic removal treatment to transform them from hazardous solid waste into ordinary solid waste, ensuring safety and preventing harm to human health. The existing technology uses wet arsenic removal; however, wet arsenic removal has insufficient purification depth, low capacity, and high processing costs, failing to meet the needs of modern production. Summary of the Invention

[0003] To overcome the above-mentioned technical defects, the present invention provides a hot air circulation arsenic removal system and method, which can improve the arsenic removal capacity of brick stacks and reduce costs.

[0004] This invention is implemented according to the following technical solution:

[0005] This invention provides a hot air circulating arsenic removal system, comprising:

[0006] The arsenic removal group includes multiple arsenic removal furnaces; in one sub-cycle, the multiple arsenic removal furnaces have loading and unloading, drying, reduction, sublimation and cooling working states respectively; each arsenic removal furnace can only be in one working state in one sub-cycle; each arsenic removal furnace rotates to another working state in the next sub-cycle according to the current working state, following the working state of loading and unloading, drying, reduction, sublimation and cooling.

[0007] A hot air generating unit, which is connected to the arsenic removal unit, is used to provide hot air to the arsenic removal unit;

[0008] A flue gas treatment unit, which is connected to the arsenic removal unit, is used to receive and treat the flue gas from the arsenic removal unit.

[0009] This application utilizes hot air circulation to sublimate arsenic and remove it from the brick stack as waste gas, thereby achieving arsenic removal treatment. The multiple arsenic removal furnaces in this application share a hot air generation group and a flue gas treatment group, and the working status of multiple arsenic removal furnaces is reasonably allocated in one sub-cycle, so that the production needs of multiple arsenic removal furnaces can be met with a limited number of hot air generation groups and flue gas treatment groups, thereby reducing costs and increasing production capacity.

[0010] In one embodiment, the hot air generating group includes: a drying group connected to the arsenic removal group for providing a first hot air to the arsenic removal group; a hot air group connected to the arsenic removal group for providing a second hot air to the arsenic removal group; and the hot air group connected to the flue gas treatment group for receiving exhaust gas generated by the flue gas treatment group.

[0011] In one embodiment, the hot air circulation arsenic removal system further includes a cold air unit connected to the arsenic removal unit for supplying cold air to the arsenic removal unit.

[0012] Alternatively, it can be used to provide a third hot air to the arsenic removal unit after being mixed with the second hot air.

[0013] Alternatively, it can be used to provide a first airflow and a second airflow, wherein the first airflow is directed to the arsenic removal group as cold air, and the second airflow is mixed with the second hot air to provide the arsenic removal group as a third hot air;

[0014] The temperature of the third hot air is higher than that of the first hot air.

[0015] In one embodiment, the cooling air unit is connected to the flue gas treatment unit and is used to receive exhaust gas generated by the flue gas treatment unit.

[0016] In one embodiment, the arsenic removal furnace is connected to the drying group via a drying valve, and is used to receive the first hot air when the drying valve is opened;

[0017] The arsenic removal furnace is connected to the cold air group and the hot air group via a reduction valve, and is used to receive the third hot air when the reduction valve is opened;

[0018] The arsenic removal furnace is connected to the hot air group via a sublimation valve, and is used to receive the second hot air when the sublimation valve is opened;

[0019] The arsenic removal furnace is connected to the cold air group via a cooling valve, and is used to receive the cold air when the cooling valve is opened;

[0020] The arsenic removal furnace is connected to the flue gas treatment group via a circulation valve, which is used to input flue gas into the flue gas treatment group when the circulation valve is opened.

[0021] In one embodiment, the hot air circulating arsenic removal system further includes a dehumidification group, which is connected to the arsenic removal furnace via a dehumidification valve and is used to discharge the flue gas containing water vapor inside the arsenic removal furnace when the dehumidification valve is opened.

[0022] In one embodiment, the flue gas treatment group includes a flue gas treatment device and a condensation and arsenic collection device;

[0023] The condensation and arsenic collection device is connected to the arsenic removal furnace via a low-temperature direct exhaust valve, and is used to receive flue gas in the arsenic removal furnace when the low-temperature direct exhaust valve is opened.

[0024] The flue gas treatment device is connected to the condensation and arsenic collection device and is used to receive flue gas from the condensation and arsenic collection device.

[0025] In one embodiment, the drying unit includes a drying fan and a first heat exchanger, the first heat exchanger being connected to the arsenic removal furnace, the flue gas treatment unit and the drying fan, for transferring the heat of the flue gas discharged from the arsenic removal furnace to the airflow output by the drying fan to form a first hot air.

[0026] In one embodiment, the hot air assembly includes a hot air blower, a heating device, and a second heat exchanger, wherein the air outlet of the hot air blower is connected to the heating device.

[0027] The second heat exchanger is connected to the air inlet of the arsenic removal furnace, the flue gas treatment group and the hot air blower, and is used to transfer the heat of the flue gas discharged from the arsenic removal furnace to the airflow that is about to enter the hot air blower.

[0028] The present invention also provides a hot air circulation arsenic removal method, which includes:

[0029] S1: Based on the working status of multiple arsenic removal furnaces in the previous sub-cycle, adjust the working status of multiple arsenic removal furnaces in the current sub-cycle and perform corresponding work in the order of loading and unloading, drying, reduction, sublimation and cooling, until multiple arsenic removal furnaces complete the current sub-cycle.

[0030] The production cycle includes multiple sub-cycles; each of the arsenic removal furnaces is in only one working state in one sub-cycle, and the multiple arsenic removal furnaces have loading and unloading, drying, reduction, sublimation and cooling working states in one sub-cycle;

[0031] S2: When the arsenic removal furnace is in the loading and unloading state, take out the brick stack that has been dearsenic removed and put it back into the brick stack to be dearsenic removed, and repeat the operation of step S1. Attached Figure Description

[0032] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0033] Figure 1 This is a schematic diagram of the hot air circulation arsenic removal system of the present invention;

[0034] Figure 2 This is one of the partial schematic diagrams of the hot air circulation arsenic removal system of the present invention;

[0035] Figure 3 This is a schematic diagram of the arsenic removal furnace in the hot air circulating arsenic removal system of the present invention;

[0036] Figure 4 This is a second partial schematic diagram of the hot air circulation arsenic removal system of the present invention. Detailed Implementation

[0037] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] To better illustrate the present invention, the invention will now be described in further detail with reference to the accompanying drawings.

[0039] It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0040] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0041] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0043] Combination Figures 1 to 4 As shown, the present invention provides a hot air circulation arsenic removal system, which includes:

[0044] The arsenic removal group 10 includes multiple arsenic removal furnaces 110; in one sub-cycle, the multiple arsenic removal furnaces 110 have loading and unloading, drying, reduction, sublimation and cooling working states respectively; each arsenic removal furnace 110 can only be in one working state in one sub-cycle; each arsenic removal furnace 110 rotates to another working state in the next sub-cycle according to the current working state, following the working state of loading and unloading, drying, reduction, sublimation and cooling.

[0045] A hot air generating group, connected to the arsenic removal group, is used to provide hot air to the arsenic removal group; the hot air generating group includes: a drying group 20, connected to the arsenic removal group 10, for providing first hot air to the arsenic removal group 10;

[0046] Hot air unit 30, which is connected to the arsenic removal unit 10, is used to provide a second hot air to the arsenic removal unit 10;

[0047] Flue gas treatment unit 40, which is connected to the arsenic removal unit 10, is used to receive and treat the flue gas from the arsenic removal unit 10.

[0048] It should be noted that the arsenic removal furnace 110 of the present invention performs arsenic removal treatment on brick stacks in five working states, specifically:

[0049] Loading and unloading status: Take out the brick stacks that have been dearseniced and put the brick stacks to be dearseniced into the dearsenic removal furnace 110;

[0050] Drying process: The brick stacks to be dearsenic removed in the dearsenic removal furnace 110 are dried.

[0051] Reduction state: The brick stacks to be dearsenic removed in the dearsenic removal furnace 110 are subjected to reduction treatment so that elemental arsenic is displaced from the brick stacks;

[0052] Sublimation state: The brick stacks to be dearsenic removed in the dearsenic removal furnace 110 are subjected to sublimation treatment, so that the elemental arsenic is sublimated into a gaseous state;

[0053] Cooling process: Cooling treatment is performed on the arsenic-removed brick stacks inside the arsenic removal furnace 110.

[0054] To fully understand the technical content of this invention, the present invention will be specifically described using an example of five arsenic removal furnaces 110 sharing one drying group 20, one hot air group 30, and one flue gas treatment group 40. The five arsenic removal furnaces 110 are designated as arsenic removal furnace #1, #2, #3, #4, and #5. Within one sub-cycle (which can be set to one day), arsenic removal furnace #110 is in the loading / unloading state, arsenic removal furnace #2 is in the drying state, arsenic removal furnace #3 is in the reduction state, arsenic removal furnace #4 is in the sublimation state, and arsenic removal furnace #5 is in the cooling state. That is, within one sub-cycle, the multiple arsenic removal furnaces 110 respectively have loading / unloading, drying, reduction, sublimation, and cooling operating states; each arsenic removal furnace 110 can only be in one operating state within one sub-cycle.

[0055] This invention rationally allocates the working states of the five arsenic removal furnaces 110. Within one sub-cycle, furnace #1 is in the loading / unloading state, where workers remove the arsenic-removed brick stacks and place the brick stacks to be removed into furnace #1. Furnace #2 is in the drying state, where the drying unit 20 provides first hot air to furnace #2 to dry the brick stacks to be removed, and to expel the moisture (moisture-laden flue gas) generated by the brick stacks to be removed, preventing moisture from affecting the subsequent reduction and sublimation states. Furnace #3 is in the reduction state, where hot air... The second hot air provided by the air group 30 is mixed and cooled before being input into the No. 3 arsenic removal furnace 110 to reduce the brick stacks to be dearsenic removed in the No. 3 arsenic removal furnace 110, so that elemental arsenic is displaced from the brick stacks; the No. 4 arsenic removal furnace 110 is in a sublimation state, and the second hot air provided by the hot air group 30 is input into the No. 4 arsenic removal furnace 110 to sublimate the arsenic that has been reduced to elemental arsenic in the No. 4 arsenic removal furnace 110, so that the elemental arsenic is sublimated into a gaseous state and discharged, thus completing the arsenic removal process; the No. 5 arsenic removal furnace 110 is in a cooling state, and the dearsenic removed brick stacks in the No. 5 arsenic removal furnace 110 are cooled down so that they can be loaded and unloaded in the next sub-cycle when switching to the loading and unloading state. This invention allows workers in the same shift to load and unload brick stacks in only one arsenic removal furnace 110 within a single sub-cycle, thus rationally allocating labor and enabling daily access to and from the arsenic removal furnace 110, resulting in stable and controllable output. A drying group 20 only needs to perform drying treatment in one arsenic removal furnace 110 within a single sub-cycle, ensuring the drying effect. A hot air group 30 can maintain a constant high-temperature output, which improves the durability of the heating wires in the hot air group 30 and reduces maintenance costs.

[0056] It should be noted that if each arsenic removal furnace 110 is to operate independently (i.e., each arsenic removal furnace 110 is equipped with a drying group 20 and a hot air group 30), then if there are 5 arsenic removal furnaces 110, then 5 drying groups 20 and 5 hot air groups 30 will be required, and the number of workers will also increase, leading to increased costs. Moreover, as the working state of the arsenic removal furnace 110 changes (i.e., loading and unloading → drying → reduction → sublimation → cooling), the working temperature of the hot air group 30 will also change from low to high to low, resulting in reduced durability of the heating wire.

[0057] Therefore, this application utilizes hot air circulation to sublimate arsenic and remove it from the brick stack as waste gas, thus achieving arsenic removal treatment. The multiple arsenic removal furnaces 110 of this invention share a drying group 20, a hot air group 30, and a flue gas treatment group 40. Furthermore, the working states of the multiple arsenic removal furnaces 110 are rationally allocated within a sub-cycle, ensuring that the production needs of multiple arsenic removal furnaces 110 can be met with a limited number of drying groups 20, hot air groups 30, and flue gas treatment groups 40. By rationally staggering the working states of each arsenic removal furnace 110, workers and the hot air group 30 can be reasonably allocated, reducing costs while increasing production capacity. Moreover, the arsenic is removed from the brick stack as waste gas. This application removes arsenic through reduction sublimation, avoiding the introduction of other impurity ions that are easily introduced in wet arsenic removal processes. This is because the waste residue (arsenic sulfide) produced by wet arsenic removal is a difficult-to-treat hazardous solid waste with extremely high safety risks. It also avoids the arsenic trioxide (commonly known as arsenic, which is easily soluble in water) produced by incineration.

[0058] To achieve hot air circulation, in one embodiment, the hot air group 30 is connected to the flue gas treatment group 40 to receive the exhaust gas generated by the flue gas treatment group 40. The flue gas inside the arsenic removal furnace 110 in its reducing and sublimated states becomes exhaust gas (containing no arsenic or trace amounts of arsenic) after being treated in the flue gas treatment group 40. This exhaust gas then enters the hot air group 30 and is reintroduced into the arsenic removal furnace 110, thus effectively utilizing the exhaust gas to achieve hot air circulation.

[0059] In one embodiment, the hot air circulation arsenic removal system further includes a cold air group 50 connected to the arsenic removal group 10, for providing cold air to the arsenic removal group, or for providing a third hot air to the arsenic removal group after mixing with the second hot air, or for providing a first airflow and a second airflow, wherein the first airflow provides cold air to the arsenic removal group, and the second airflow is mixed with the second hot air to provide a third hot air to the arsenic removal group; wherein the temperature of the third hot air is higher than the temperature of the first hot air.

[0060] Specifically, the cold air group can provide cold air to the arsenic removal group independently. For example, when cooling down the arsenic-removed brick stacks in the No. 5 arsenic removal furnace 110 mentioned above, the cold air provided by the cold air group 50 can be used to cool down the arsenic-removed brick stacks.

[0061] The cold air provided by the cold air group can also be mixed with the second hot air separately to provide a third hot air to the arsenic removal group, for example, to reduce the brick stacks to be dearsenic removed in the No. 3 arsenic removal furnace 110 mentioned above, so that elemental arsenic is displaced from the brick stacks.

[0062] The cold air group can also provide two airflows simultaneously, namely a first airflow and a second airflow; the first airflow is directed to the arsenic removal group for example, to cool down the arsenic-removed brick stacks in the aforementioned No. 5 arsenic removal furnace 110, using the cold air provided by the cold air group 50 to cool down the arsenic-removed brick stacks; the second airflow is mixed with the second hot air and then provides a third hot air to the arsenic removal group for example, to reduce the arsenic-removed brick stacks in the aforementioned No. 3 arsenic removal furnace 110, so that elemental arsenic is displaced from the brick stacks;

[0063] The second hot air provided by the hot air group 30 mentioned above can be mixed with the cold air provided by the cold air group 50 to cool it into a third hot air, or it can be mixed with other pure nitrogen external air sources to cool it before being fed into the No. 3 arsenic removal furnace 110.

[0064] Furthermore, the cold air group 50 is connected to the flue gas treatment group 40 and is used to receive the exhaust gas generated by the flue gas treatment group 40. The flue gas inside the arsenic removal furnace 110 in the reduction, sublimation, and cooling states becomes exhaust gas after entering the flue gas treatment group 40 for flue gas treatment. The exhaust gas enters the cold air group 50 and is then reintroduced into the arsenic removal furnace 110. This makes reasonable use of the heat of the exhaust gas, allowing the lower-temperature exhaust gas to mix with the higher-temperature second hot air to form a third hot air. This eliminates the need for cooling treatment of the heating wire in the hot air group 30, improving the durability of the heating wire.

[0065] In one embodiment, the arsenic removal furnace 110 is connected to the drying group 20 via a drying valve, for receiving the first hot air when the drying valve is open; the arsenic removal furnace 110 is connected to the cold air group 50 and the hot air group 30 via a reduction valve, for receiving the third hot air when the reduction valve is open; the arsenic removal furnace 110 is connected to the hot air group 30 via a sublimation valve, for receiving the second hot air when the sublimation valve is open; the arsenic removal furnace 110 is connected to the cold air group 50 via a cooling valve, for receiving the cold air when the cooling valve is open; and the arsenic removal furnace 110 is connected to the flue gas treatment group 40 via a circulation valve, for inputting flue gas into the flue gas treatment group 40 when the circulation valve is open.

[0066] Specifically, let's continue with the explanation using the five arsenic removal furnaces 110 mentioned above as examples:

[0067] When the No. 1 arsenic removal furnace 110 is in the loading and unloading state, the drying valve, reduction valve, sublimation valve, cooling valve and circulation valve of the No. 1 arsenic removal furnace 110 are closed. At this time, the gas from the drying group 20, hot air group 30 and cold air group 50 will not enter the No. 1 arsenic removal furnace 110, and it also prevents the arsenic-containing gas from the flue gas treatment group 40 from flowing back into the No. 1 arsenic removal furnace 110. Workers can safely remove the arsenic-removed brick stacks in the No. 1 arsenic removal furnace 110 and put the brick stacks to be removed into the arsenic removal furnace 110.

[0068] Arsenic removal furnace 110 is in the drying state. The drying valve of arsenic removal furnace 110 is open, and the reduction valve, sublimation valve and cooling valve are closed. At this time, the drying group 20 inputs the first hot air into arsenic removal furnace 110 to dry the brick stacks to be dearsenic removed.

[0069] Arsenic removal furnace 110 is in a reduction state. The reduction valve and circulation valve of arsenic removal furnace 110 are open, while the drying valve, sublimation valve and cooling valve are closed. At this time, the cold air provided by the cold air group 50 and the second hot air provided by the hot air group 30 are mixed to form the third hot air. The third hot air is input into arsenic removal furnace 110 to reduce the brick stacks to be dearsenic removed, so that the elemental arsenic is replaced out of the brick stacks. The flue gas enters the flue gas treatment group 40 through the circulation valve.

[0070] Arsenic removal furnace 110 is in a sublimation state. The sublimation valve and circulation valve of arsenic removal furnace 110 are open, while the drying valve, reduction valve and cooling valve are closed. At this time, the hot air group 30 inputs the second hot air into arsenic removal furnace 110 to sublimate the brick stack to be dearsenic removed, so that the arsenic element (displaced by arsenic removal furnace 110 in a reduction state) sublimates into a gaseous state. The arsenic-containing waste gas enters the flue gas treatment group 40 through the circulation valve.

[0071] The No. 5 arsenic removal furnace 110 is in a cooling state. The cooling valve and circulation valve of the No. 5 arsenic removal furnace 110 are open, while the drying valve, reduction valve and sublimation valve are closed. At this time, the cold air group 50 inputs cold air into the No. 5 arsenic removal furnace 110 to cool down the brick stack that has been dearseniced. The gas then enters the flue gas treatment group 40 through the circulation valve.

[0072] It should be noted that the above-mentioned arsenic removal furnaces 1#, 2#, 3#, 4#, and 5# operates simultaneously within the same sub-cycle. Furthermore, each of the aforementioned arsenic removal furnaces 110 is equipped with a furnace pressure detection device (for detecting the gas pressure within the furnace) and a kiln pressure valve. By adjusting the circulation valve and the kiln pressure valve, the gas pressure inside the arsenic removal furnace 110 is kept negative during the drying, reduction, sublimation, and cooling states, preventing gas leakage from the furnace to the outside.

[0073] Furthermore, the hot air circulation arsenic removal system also includes a dehumidification group 70, which is connected to the arsenic removal furnace 110 via a dehumidification valve. This dehumidification group is used to discharge the water-laden flue gas inside the arsenic removal furnace 110 when the dehumidification valve is open. When the arsenic removal furnace 110 is in a drying state, the drying valve of the arsenic removal furnace 110 is open, while the reduction valve, sublimation valve, and cooling valve are closed. At this time, the drying group 20 inputs the first hot air into the arsenic removal furnace 110 to dry the brick stacks to be dearsenic removed. The dehumidification valve is open, and the moisture generated by the brick stacks to be dearsenic removed inside the arsenic removal furnace 110 is discharged through the dehumidification valve to the dehumidification group, and then discharged out of the arsenic removal furnace 110 by the dehumidification group.

[0074] In one embodiment, the hot air circulation arsenic removal system further includes an under-vehicle fan 60, which is connected to each of the arsenic removal furnaces 110, and each arsenic removal furnace 110 has a corresponding under-vehicle air valve. When the arsenic removal furnace 110 is in the loading and unloading state, its corresponding under-vehicle air valve is opened, and the under-vehicle fan 60 extracts the residual gas in the arsenic removal furnace 110 to facilitate worker operations.

[0075] Furthermore, the hot air circulation arsenic removal system also includes multiple suction hoods, which are provided for multiple arsenic removal furnaces 110 and located outside the arsenic removal furnaces 110. These suction hoods are used to prevent gas from leaking out of the furnace and to promptly remove the gas, thus protecting the safety of workers outside the furnace.

[0076] In one embodiment, the drying unit 20 includes a drying fan 210 and a first heat exchanger 220. The first heat exchanger 220 is connected to the arsenic removal furnace 110, the flue gas treatment unit 40, and the drying fan 210, and is used to transfer the heat of the flue gas discharged from the arsenic removal furnace 110 to the airflow output by the drying fan 210 to form first hot air. Specifically, the flue gas (with a certain temperature) discharged from the arsenic removal furnace 110 through the circulation valve passes through the first heat exchanger 220, and the heat is transferred to the airflow output by the drying fan 210 through heat exchange, so that the airflow forms first hot air, making reasonable use of the heat of the flue gas discharged from the arsenic removal furnace 110. Further, the air outlet of the drying unit 20 is connected to the arsenic removal unit 10 through a drying pipe, and a temperature detection device is installed on the drying pipe to monitor the temperature of the first hot air; wherein, the temperature of the first hot air is maintained at 150℃~170℃.

[0077] In one embodiment, the hot air circulating arsenic removal system further includes a mixing flue 80, which is connected to each of the arsenic removal furnaces 110 and is used to receive and mix the flue gas discharged from each of the arsenic removal furnaces 110 through the circulating valve; the mixing flue 80 is connected to the flue gas treatment group 40 and is used to uniformly output the mixed flue gas to the flue gas treatment group 40.

[0078] Furthermore, the mixing flue 80 is equipped with an air supply valve to ensure that the arsenic is fully oxidized and combined before entering the flue gas treatment device 410 for arsenic removal treatment.

[0079] In one embodiment, the hot air assembly 30 includes a hot air blower 310, a heating device 320, and a second heat exchanger 330. The outlet of the hot air blower 310 is connected to the heating device 320. The second heat exchanger 330 is connected to the arsenic removal furnace 110, the flue gas treatment assembly 40, and the inlet of the hot air blower 310, and is used to transfer the heat of the flue gas discharged from the arsenic removal furnace 110 to the airflow about to enter the hot air blower 310. Specifically, the flue gas (with a certain temperature) discharged from the arsenic removal furnace 110 through the circulation valve passes through the first heat exchanger 220 and then the second heat exchanger 330, transferring heat to the airflow about to enter the hot air blower 310 through heat exchange, so as to reduce the temperature difference between the airflow at the outlet of the hot air blower 310 and the heating device 320, making reasonable use of the heat of the flue gas discharged from the arsenic removal furnace 110 and reducing energy consumption. In another embodiment, the flue gas (with a certain temperature) discharged from the arsenic removal furnace 110 by the circulation valve does not pass through the first heat exchanger 220, but directly passes through the second heat exchanger 330.

[0080] Furthermore, the outlet of the hot air unit 30 is connected to the arsenic removal unit 10 via a reduction pipe and a sublimation pipe; the reduction pipe is also connected to the cold air unit 50 to reduce the temperature after mixing with the cold air and outputting a third airflow; a heat source valve is provided on the reduction pipe to adjust the input of the second hot air, thereby cooperating with the cold air to adjust the temperature of the third hot air; a temperature detection device is provided on the reduction pipe to monitor the temperature of the third hot air; wherein, the temperature of the third hot air is maintained at 260℃~450℃; a temperature detection device is provided on the sublimation pipe to monitor the temperature of the second hot air; wherein, the temperature of the second hot air is maintained at 700℃~850℃.

[0081] Furthermore, the heating device 320 includes a hot air furnace, which is equipped with a heating wire. Due to the special nature of this hot air circulation system, the heating wire only needs to be kept at a high temperature during operation, thus improving durability.

[0082] Furthermore, the flue gas treatment group 40 includes a flue gas treatment device 410 and a condensation and arsenic collection device 420; the condensation and arsenic collection device 420 is connected to the arsenic removal furnace 110 via a low-temperature direct exhaust valve, and is used to receive flue gas in the arsenic removal furnace 110 when the low-temperature direct exhaust valve is opened; the flue gas treatment device 410 is connected to the condensation and arsenic collection device 420, and is used to receive flue gas from the condensation and arsenic collection device 420. When the arsenic removal furnace 110 is in a cooling state, the cooling valve, circulation valve, and low-temperature direct exhaust valve of the arsenic removal furnace 110 are opened, while the drying valve, reduction valve, and sublimation valve are closed. At this time, the cold air group 50 inputs cold air into the arsenic removal furnace 110 to cool down the arsenic-removed brick stacks. The arsenic removal furnace 110 gradually cools down. When the temperature inside the arsenic removal furnace 110 drops to the preset temperature (120℃~130℃), all the flue gas is sent directly to the condensation and arsenic collection device 420 through the low-temperature direct exhaust valve to prevent the gas that is prone to causing agglomeration in the first heat exchanger 220 and the second heat exchanger 330 from entering the first heat exchanger and the second heat exchanger, thus preventing damage to the heat exchangers. Then the circulation valve is closed to prevent the flue gas from agglomerating and causing blockage when passing through the heat exchangers.

[0083] Furthermore, the flue gas treatment device 410 is provided with an exhaust gas end and an air replenishment end. The exhaust gas end is equipped with an oxygen analyzer to detect the oxygen content of the exhaust gas. When the oxygen content of the exhaust gas exceeds 5%, the replenishment valve of the air replenishment end of the flue gas treatment device 410 is opened to replenish nitrogen to the flue gas treatment device 410, ensuring that the oxygen content of the treated exhaust gas is always below 5%, and then sent into the arsenic removal furnace through the hot air group. Moreover, it dilutes the oxygen content of the entire flue gas treatment device 410, ensuring that the flue gas treatment device 410 operates in a low-oxygen environment, reducing the risk of generating other new harmful impurities during production.

[0084] Furthermore, the exhaust gas end is connected to the air inlet of the hot air blower 310 via a secondary section pipeline, for providing the hot air blower 310 with airflow heated by the second heat exchanger 330. In one embodiment, the secondary section pipeline is also connected to an arsenic sulfide section outside the system via an arsenic sulfide valve, for supplementing the air source for the arsenic sulfide section.

[0085] In one embodiment, the cooling air unit 50 includes a first cooling fan 510 and a second cooling fan 520. The air inlet of the first cooling fan 510 is connected to the exhaust gas end of the flue gas treatment device 410 via a circulation pipe to receive the exhaust gas from the flue gas treatment device 410. The air outlet of the first cooling fan 510 is connected to the arsenic removal unit 10 via a cooling pipe. The air inlet of the second cooling fan 520 is connected to the flue gas treatment device 410 to receive the exhaust gas from the delayed treatment device. The air outlet of the second cooling fan 520 is connected to the reduction pipe via a pipe equipped with a cooling valve to adjust the cold air input, thereby coordinating with the second hot air to adjust the temperature of the third hot air.

[0086] In one embodiment, to protect the flue gas treatment unit 40 from damage by the pressure inside the pipe, a pressure relief valve and a pressure relief port are installed in the circulation pipeline to ensure that the pressure inside the pipeline is within the working pressure.

[0087] The working principle of the hot air circulation arsenic removal system in this application is as follows:

[0088] With the No. 1 arsenic removal furnace 110 in the loading and unloading state, the suction hood SH1 and the undercarriage air valve CARD1 are opened to extract the residual gas inside the No. 1 arsenic removal furnace. The drying valve DD1, reduction valve RD1, sublimation valve SD1, cooling valve CD1, kiln pressure valve PD1, low temperature direct exhaust valve LTD1, moisture exhaust valve ED1 and circulation valve LD1 of the No. 1 arsenic removal furnace 110 are closed. At this time, the gas from the drying group 20, hot air group 30 and cold air group 50 will not enter the No. 1 arsenic removal furnace 110, and it also prevents the arsenic-containing gas from the flue gas treatment group 40 from flowing back into the No. 1 arsenic removal furnace 110. Workers can safely remove the arsenic-removed brick stacks in the No. 1 arsenic removal furnace 110 and put the brick stacks to be removed into the arsenic removal furnace 110.

[0089] Arsenic removal furnace 110 is in drying mode. Open the suction hood SH2 and start the drying fan 210. The drying valve DD2 of arsenic removal furnace 110 is opened, and the reduction valve RD2, sublimation valve SD2, low temperature direct exhaust valve LTD2 and cooling valve CD2 are closed. At this time, the drying group 20 inputs the first hot air into arsenic removal furnace 110 to dry the brick stacks to be dearsenic removed. Open the dehumidification valve ED2 and the dehumidification group to directly discharge the flue gas containing moisture.

[0090] Arsenic removal furnace 110 is in reduction state. The suction hood SH3 is opened and the second cooling fan and hot air fan are started. The reduction valve RD3 and circulation valve LD3 of arsenic removal furnace 110 are opened, and the drying valve DD3, sublimation valve SD3, low temperature direct exhaust valve LTD3, dehumidification valve ED3 and cooling valve CD3 are closed. At this time, the cold air provided by the second cooling fan and the second hot air provided by the hot air group 30 are mixed to form the third hot air. The third hot air is input into arsenic removal furnace 110 to reduce the brick stacks to be dearsenic removed, so that the elemental arsenic is replaced out of the brick stacks. The flue gas enters the flue gas treatment group 40 through the circulation valve LD3.

[0091] Arsenic removal furnace 110 is in the sublimation state. The suction hood SH4 is opened and the hot air fan is started. The sublimation valve SD4 and circulation valve LD4 of arsenic removal furnace 110 are opened, and the drying valve DD4, reduction valve RD4, low temperature direct discharge valve LTD4, dehumidification valve ED4 and cooling valve CD4 are closed. At this time, the hot air group 30 inputs the second hot air into arsenic removal furnace 110 to sublimate the brick stack to be dearsenic removed, so that the arsenic element (displaced by arsenic removal furnace 110 in the reduction state) sublimates into a gaseous state. The arsenic-containing waste gas enters the flue gas treatment group 40 through the circulation valve LD4.

[0092] Arsenic removal furnace 110 is in a cooling state. The suction hood SH5 is opened and the first cooling fan is started. Cooling valve CD5 and circulation valve LD5 of furnace 110 are opened, while drying valve DD5, reduction valve RD5, low-temperature direct exhaust valve LTD5, dehumidification valve ED5, and sublimation valve SD5 are closed. At this time, the first cooling fan introduces cold air into furnace 110 to cool the de-arsenic-removed brick stacks. The gas then enters the flue gas treatment group 40 via the circulation valve. When the temperature inside furnace 110 drops to the preset temperature (120℃~130℃), the low-temperature direct exhaust valve LTD5 is opened, and some flue gas is directly sent to the arsenic condensation and collection device 420 via the low-temperature direct exhaust valve. Then, circulation valve LD5 is closed to prevent positive pressure from forming inside furnace 110 during valve switching, which could lead to flue gas leakage.

[0093] The present invention also provides a hot air circulation arsenic removal method, which includes:

[0094] S1: Based on the working status of multiple arsenic removal furnaces in the previous sub-cycle, adjust the working status of multiple arsenic removal furnaces in the current sub-cycle and perform corresponding work in the order of loading and unloading, drying, reduction, sublimation and cooling, until multiple arsenic removal furnaces complete the current sub-cycle.

[0095] Specifically, if the previous sub-cycle of the No. 2 arsenic removal furnace was in the loading and unloading state, then the working state of the No. 2 arsenic removal furnace in the current sub-cycle will be adjusted to the working state, and will continue until the current sub-cycle is completed, at which point the working state of the No. 2 arsenic removal furnace will be adjusted to the reduction state.

[0096] The production cycle includes multiple sub-cycles; each of the arsenic removal furnaces is in only one working state in one sub-cycle, and the multiple arsenic removal furnaces have loading and unloading, drying, reduction, sublimation and cooling working states in one sub-cycle;

[0097] S2: When the arsenic removal furnace is in the loading and unloading state, take out the brick stack that has been dearsenic removed and put it back into the brick stack to be dearsenic removed, and repeat the operation of step S1.

[0098] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A hot air circulating arsenic removal system, characterized in that, include: The arsenic removal unit includes multiple arsenic removal furnaces. In one sub-cycle, the multiple arsenic removal furnaces have loading / unloading, drying, reduction, sublimation, and cooling operating states respectively. Each arsenic removal furnace can only be in one operating state in one sub-cycle. Each arsenic removal furnace rotates to another operating state in the next sub-cycle according to the current operating state, following the loading / unloading, drying, reduction, sublimation, and cooling operating states. When the arsenic removal furnace is in the loading / unloading state, the brick stacks that have been dearsenic removed are removed and then the brick stacks to be dearsenic removed are put back in. A hot air generating unit, which is connected to the arsenic removal unit, is used to provide hot air to the arsenic removal unit; The hot air generating group includes: A drying unit, connected to the arsenic removal unit, is used to provide the arsenic removal unit with first hot air to dry the brick stacks to be dearsenic removed. The drying unit includes a drying fan and a first heat exchanger. The first heat exchanger is connected to the arsenic removal furnace, the flue gas treatment unit, and the drying fan, and is used to transfer the heat of the flue gas discharged from the arsenic removal furnace to the airflow output by the drying fan to form the first hot air. A hot air unit, which is connected to the arsenic removal unit, is used to provide a second hot air to the arsenic removal unit, and the second hot air performs sublimation treatment on the brick stack to be arsenic removed. The hot air unit is connected to the flue gas treatment unit and is used to receive the exhaust gas generated by the flue gas treatment unit; The hot air circulation arsenic removal system also includes a cold air group connected to the arsenic removal group. The cold air group is used to provide cold air to the arsenic removal group and to mix with the second hot air to provide a third hot air to the arsenic removal group. The third hot air reduces the brick stack to be dearsenic removed. The temperature of the third hot air is higher than that of the first hot air. A flue gas treatment unit, which is connected to the arsenic removal unit, is used to receive and treat the flue gas from the arsenic removal unit; The flue gas treatment group includes a flue gas treatment device and a condensation and arsenic collection device. The condensation and arsenic collection device is connected to the arsenic removal furnace via a low-temperature direct exhaust valve, and is used to receive flue gas in the arsenic removal furnace when the low-temperature direct exhaust valve is opened. The flue gas treatment device is connected to the condensation and arsenic collection device and is used to receive flue gas from the condensation and arsenic collection device. The flue gas is sent to the condensation and arsenic collection device after heat exchange in the first heat exchanger.

2. The hot air circulating arsenic removal system according to claim 1, characterized in that: The cooling air unit is connected to the flue gas treatment unit and is used to receive the exhaust gas generated by the flue gas treatment unit.

3. The hot air circulating arsenic removal system according to claim 1, characterized in that: The arsenic removal furnace is connected to the drying group via a drying valve, and is used to receive the first hot air when the drying valve is opened; The arsenic removal furnace is connected to the cold air group and the hot air group via a reduction valve, and is used to receive the third hot air when the reduction valve is opened; The arsenic removal furnace is connected to the hot air group via a sublimation valve, and is used to receive the second hot air when the sublimation valve is opened; The arsenic removal furnace is connected to the cold air group via a cooling valve, and is used to receive the cold air when the cooling valve is opened; The arsenic removal furnace is connected to the flue gas treatment group via a circulation valve, which is used to input flue gas into the flue gas treatment group when the circulation valve is opened.

4. The hot air circulating arsenic removal system according to claim 3, characterized in that: The hot air circulation arsenic removal system also includes a dehumidification group, which is connected to the arsenic removal furnace via a dehumidification valve and is used to discharge the flue gas containing water vapor from the arsenic removal furnace when the dehumidification valve is opened.

5. The hot air circulating arsenic removal system according to claim 1, characterized in that: The hot air unit includes a hot air blower, a heating device, and a second heat exchanger, with the air outlet of the hot air blower connected to the heating device. The second heat exchanger is connected to the air inlet of the arsenic removal furnace, the flue gas treatment group and the hot air blower, and is used to transfer the heat of the flue gas discharged from the arsenic removal furnace to the airflow that is about to enter the hot air blower.

6. A hot air circulation method for arsenic removal, characterized in that, The method of using the hot air circulation arsenic removal system as described in any one of claims 1-5 includes: S1: Based on the working status of multiple arsenic removal furnaces in the previous sub-cycle, adjust the working status of multiple arsenic removal furnaces in the current sub-cycle and perform corresponding work in the order of loading and unloading, drying, reduction, sublimation and cooling, until multiple arsenic removal furnaces complete the current sub-cycle. The production cycle includes multiple sub-cycles; each of the arsenic removal furnaces is in only one working state in one sub-cycle, and the multiple arsenic removal furnaces have loading and unloading, drying, reduction, sublimation and cooling working states in one sub-cycle; S2: When the arsenic removal furnace is in the loading and unloading state, take out the brick stack that has been dearsenic removed and put it back into the brick stack to be dearsenic removed, and repeat the operation of step S1.

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