Laboratory acid waste gas purification treatment device with self-cleaning function

Abstract

The utility model relates to a laboratory acid waste gas purification treatment device with a self-cleaning function, which comprises a fuming cupboard, the fuming cupboard is communicated with a spray adsorption tower through a breather pipe, the spray adsorption tower is communicated with an air inlet of a centrifugal fan through an exhaust pipe, and an air outlet of the centrifugal fan is communicated with a discharge chimney; the fuming cupboard comprises a gas collecting hood and a working table, and the gas collecting hood is arranged over the working table. The spray adsorption tower is sequentially provided with a demisting layer, a filler layer I and a filler layer II from top to bottom, a plurality of spray headers are arranged right above the filler layer I and the filler layer II, the spray headers are communicated with a water outlet of a liquid conveying pump through spray pipes, a water inlet of the liquid conveying pump is communicated with a liquid storage tank, and a water outlet of the liquid storage tank is communicated with a water outlet of the liquid conveying pump. The liquid storage tank is arranged at the bottom of the spraying adsorption tower and is communicated with the bottom of the spraying adsorption tower. According to the device, the content of harmful substances in the acid waste gas can be greatly reduced, the harmful components in the purified gas are far lower than the emission standard, and the problem of emission to the environment is effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of waste gas treatment, in particular to a laboratory acid waste gas purification treatment device with a self-cleaning function. Background Art

[0002] The activated carbon adsorption iodine titration method has become the most common method for determining gold content in gold mines due to its simplicity, low cost, and accurate and reliable results. This method requires dissolving the gold in aqua regia, a process that produces large amounts of nitrogen oxides and small amounts of acidic waste gases such as hydrogen chloride. If these acidic waste gases are not promptly discharged, they can seriously harm the health of workers. Nitrogen oxides, in particular, are a major cause of lung cancer. Therefore, to improve the working environment, reduce occupational hazards, and effectively promote clean production, these gases must be purified before discharge.

[0003] Currently, there are two main methods for treating laboratory acid waste gas: one is to directly discharge it through a high-altitude chimney, which can improve the indoor environment to a certain extent, but will cause pollution to the atmospheric environment; the other is to collect the acid waste gas through powered ventilation, absorb it with alkaline solution, and then discharge it. This method can improve the indoor environment and purify the acid gas to a certain extent, but there are the following problems: ① The acid waste gas is not completely absorbed, and the acid waste gas condenses at the discharge port as "white smoke". The condensed small acid droplets cause serious corrosion to the surrounding structures of the discharge port; ② The ceramic packing layer of the spray tower will become clogged after a period of use and needs to be cleaned regularly; ③ When the powered ventilation is turned off, the condensed acid in the pipeline will partially flow back, resulting in excessive acid gas concentration in the laboratory and corrosion of indoor equipment and facilities; ④ When the pH value of the spray liquid in the spray tower drops to a certain value (when it is more acidic), the spray liquid in the spray tower needs to be manually replaced, which increases the labor intensity of the operators. Utility Model Content

[0004] In view of the above problems, the utility model provides a laboratory acid waste gas purification and treatment device with a self-cleaning function.

[0005] The specific technical solution of the utility model is: a laboratory acid waste gas purification and treatment device with a self-cleaning function, comprising a fume hood, which is connected to a spray adsorption tower through a ventilation pipe, and the spray adsorption tower is connected to the air inlet of a centrifugal fan through an exhaust pipe, and the air outlet of the centrifugal fan is connected to an exhaust chimney; the fume hood comprises an air collecting hood and a workbench, and the air collecting hood is arranged directly above the workbench; the spray adsorption tower is provided with a demisting layer, a packing layer 1 and a packing layer 2 in sequence from top to bottom, and a plurality of spray heads are provided directly above the packing layer 1 and the packing layer 2, and the spray heads are connected to the water outlet of an infusion pump through a spray pipe, and the water inlet of the infusion pump is connected to a liquid storage tank, and the liquid storage tank is provided at the bottom of the spray adsorption tower and is connected to the bottom of the spray adsorption tower.

[0006] Furthermore, preferably, the packing layer 1 and the packing layer 2 are made of Hakaideng environmentally friendly ball fillers.

[0007] Furthermore, preferably, the Hakaideng environmentally friendly ball filler consists of large-diameter balls and small-diameter balls, and the ratio of the number of large-diameter balls to the number of small-diameter balls is 3:1.

[0008] Furthermore, preferably, the diameter of the large-diameter ball is 76 mm, and the diameter of the small-diameter ball is 38 mm.

[0009] Furthermore, preferably, the demisting layer uses polypropylene perforated plate corrugated filler.

[0010] Furthermore, preferably, a condensate collecting tank is provided around the bottom of the gas collecting hood, one end of the condensate collecting tank is connected to a drainage pipe, and a liquid collecting bucket is provided at the bottom of the drainage pipe.

[0011] Furthermore, preferably, a plurality of guide inclined plates are provided in the ventilation pipe for guiding the acid liquid condensed in the ventilation pipe into the spray adsorption tower.

[0012] Furthermore, it is preferred that a drain port is provided on the bottom side wall of the liquid storage tank, an electric valve is installed on the drain port, and a pH detector and a liquid level meter are also installed on the liquid storage tank; a liquid inlet is provided on the top of the liquid storage tank, the liquid inlet is connected to the water outlet of the liquid supply pump through a pipeline, and the water inlet of the liquid supply pump is connected to the liquid distribution tank.

[0013] Furthermore, preferably, a stirring device is provided in the liquid distribution box.

[0014] The beneficial effects of the present invention are as follows: the present invention introduces the laboratory acid waste gas into the spray absorption tower through the fume hood for two-stage spray absorption and one-stage gas-liquid separation, which can greatly reduce the content of harmful substances in the acid waste gas, and the harmful components of the purified gas are far below the emission standards, solving the problem of "white smoke" at the discharge port. Moreover, the material selection of the packing layer and the demisting layer avoids the problem that the traditional ceramic packing layer is easily clogged after a period of use, and the demisting effect is better. The structural optimization of the fume hood and the ventilation pipe ensures that the condensed acid liquid remaining after shutdown can be drained to the corresponding device, solving the problem of excessive acid gas concentration in the laboratory and corrosion of indoor equipment caused by acid reflux; the coordinated control of the liquid storage tank and the detection equipment well realizes the automatic replacement of the spray liquid, reducing the labor intensity of the operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the main view of the utility model;

[0016] In the figure: 1-fume hood, 101-gas collection hood, 102-condensate collection tank, 103-workbench, 104-drainage pipe, 105-liquid collection barrel; 2-ventilation pipe, 201-diversion inclined plate; 3-spray adsorption tower, 301-demist layer, 302-packing layer one, 303-packing layer two, 304-spray head, 305-spray pipe, 306-infusion pump, 307-liquid storage tank, 308-drainage port, 309-pH detector, 310-liquid level gauge, 311-liquid inlet; 4-exhaust pipe; 5-centrifugal fan; 6-discharge chimney; 7-liquid distribution tank, 701-liquid supply pump, 702-stirring device. DETAILED DESCRIPTION

[0017] In order to make the technical problems and technical solutions solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0019] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0020] like Figure 1 As shown, a laboratory acid waste gas purification and treatment device with a self-cleaning function includes a fume hood 1, which is connected to a spray adsorption tower 3 through a ventilation pipe 2, and the spray adsorption tower 3 is connected to the air inlet of a centrifugal fan 5 through an exhaust pipe 4, and the air outlet of the centrifugal fan 5 is connected to an exhaust chimney 6.

[0021] The fume hood 1 includes an air collecting hood 101 and a workbench 103. The air collecting hood 101 has a conical opening and is arranged directly above the workbench 103 to collect acid waste gas generated by the laboratory operation on the workbench 103; the spray adsorption tower 3 is provided with a demisting layer 301, a packing layer 1 302 and a packing layer 2 303 from top to bottom, and a plurality of spray heads 304 are provided directly above the packing layer 1 302 and the packing layer 2 303. The spray heads 304 are connected to the water outlet of the infusion pump 306 through the spray pipe 305, and the water inlet of the infusion pump 306 is connected to the liquid storage tank 307. The liquid storage tank 307 is arranged at the bottom of the spray adsorption tower 3 and is connected to the bottom of the spray adsorption tower 3.

[0022] Working principle: When the laboratory personnel conduct laboratory operations at the workbench 103 of the fume hood 1, the centrifugal fan 5 is started. The acid waste gas generated by the laboratory is sucked into the gas collection hood 101 under the action of the centrifugal fan 5 and enters the spray adsorption tower 3 along the ventilation pipe 2. The infusion pump 306 is started to supply spray liquid (sodium carbonate alkaline solution) to the spray head 304. The acid waste gas passes through the packing layer 2 303 and the packing layer 1 302 from bottom to top. Due to the multi-pore structure of the packing layer, the acid waste gas and the spray liquid are separated in these pores. The contact reaction between the acid waste gas and the spray liquid can be fully achieved (the specific reaction process is shown in the reaction formula below), and the contact time between the acid waste gas and the spray liquid can be prolonged, so that the acid gas (i.e., HCl gas) is absorbed as much as possible and flows back into the liquid storage tank 307. The remaining gas continues to move upward into the demisting layer 301, where the demisting layer 301 separates the droplets from the gas, thereby achieving the purpose of demisting and purification. The separated clean gas is extracted by the centrifugal fan 5 and discharged into the atmosphere through the discharge chimney 6, thereby achieving the purification and discharge of the laboratory acid waste gas.

[0023] The nitrogen oxides produced in the fume hood react with the alkaline solution of sodium carbonate as follows:

[0024] 3NO2+H2O=2HNO3+NO↑

[0025] 2NO+O2= 2NO2↑

[0026] NO2+ NO +Na2CO3=2NaNO2+CO2↑

[0027] 3NaNO2+2HNO3= 3NaNO3+ H2O+2NO↑

[0028] The overall reaction formula is: 2NO2 + Na2CO3 = 2NaNO2 + NaNO3 + CO2↑

[0029] Perchloric acid gas, whose main component is hydrogen chloride gas, turns into dilute hydrochloric acid solution when it comes into contact with water, and reacts with the alkaline solution of sodium carbonate as follows:

[0030] HCl+NaOH=NaCl+H2O

[0031] Therefore, after the acid waste gas undergoes washing reaction in the two-stage packing layers of the spray adsorption tower, the treated gas is mainly composed of carbon dioxide, and the very small amount of harmful components that escape is far below the emission standard, which can greatly reduce the content of harmful substances in the acid waste gas and solve the problem of "white smoke" at the emission port.

[0032] Since traditional ceramic filler layers are prone to clogging during spraying, the filler layer 1 302 and the filler layer 2 303 of the present application use Hakaideng environmentally friendly ball fillers, and two sizes of Hakaideng environmentally friendly ball fillers are used, wherein the ratio of large diameter balls to small diameter balls is 3:1, the diameter of the large diameter balls is 76 mm, and the diameter of the small diameter balls is 38 mm. It should be noted that the Hakaideng environmentally friendly ball filler is an existing PP filler, and the present application only relates to its use, not to the improvement of its structure. The Hakaideng environmentally friendly ball filler is a hollow sphere composed of many grid-like branches connected together, and a drip rod structure is added inside the sphere. Such a structure can provide many edges for the dripping liquid to flow, converge and disperse, so that the filler surface is well wetted, and can also cause the liquid to form many droplets, promote the surface renewal of the liquid, and be beneficial to the mass transfer between the gas and liquid phases, without clogging, and can be cleaned during the circulation spraying process of the spray liquid to achieve the purpose of self-cleaning.

[0033] The demisting layer 301 of the present application adopts polypropylene orifice plate corrugated packing. It should be noted that the polypropylene orifice plate corrugated packing is an existing environmentally friendly desulfurization filler. Compared with the traditional FRP demisting filling material, the corrugated plate with small holes has the advantages of low pressure drop and high specific surface area, good demisting effect, low energy consumption and high efficiency. When the gas containing mist moves upward at a certain speed, it will collide with the polypropylene orifice plate corrugated packing under the action of gravity and inertial impact, and adhere to its surface. After diffusion and gravity, it will gradually gather. When the weight reaches a certain amount, it will separate from the polypropylene orifice plate corrugated packing layer, and the gas will continue to move upward and be discharged.

[0034] Preferably, a condensate collecting tank 102 (similar to the oil storage box design of a range hood) is provided around the bottom of the air collecting hood 101. One end of the condensate collecting tank 102 is connected to a drainage pipe 104. A liquid collecting bucket 105 is provided at the bottom of the drainage pipe 104. Several guide inclined plates 201 are provided in the ventilation pipe 2. Figure 1 A guide ramp, lower on the left and higher on the right, is installed at each of the two bends of the vent pipe 2. When the entire device is shut down, some condensed acid liquid will remain in the gas collection hood 101 and the vent pipe 2. The acid liquid in the vent pipe 101 can slide along the inner wall of the hood 101 into the condensation collection tank 102 and be collected into the liquid collection bucket 105 through the drainage pipe 104. The acid liquid in the vent pipe 2 can be diverted into the spray adsorption tower 3 through the guide ramp 201.

[0035] Preferably, a drain port 308 is provided on the bottom sidewall of the liquid storage tank 307, and an electric valve is installed on the drain port 308. The liquid storage tank 307 is also equipped with a pH detector 309 and a liquid level gauge 310. A liquid inlet 311 is provided at the top of the liquid storage tank 307. The liquid inlet 311 is connected to the water outlet of the liquid supply pump 701 via a pipe, and the water inlet of the liquid supply pump 701 is connected to the liquid distribution tank 7. In actual use, the control system can be used to automatically discharge and add spray liquid from the liquid storage tank 307. As the spray liquid circulates and sprays, the pH value of the spray liquid will continue to decrease. When the pH value detected by the pH detector 309 is lower than 1.5, the electric valve of the linkage drain port 308 is opened to discharge the liquid in the liquid storage tank 307 into the wastewater treatment pool; when the liquid in the liquid storage tank 307 is discharged, the electric valve is closed, and the liquid level meter 310 transmits the liquid level signal of the liquid storage tank 307 to the control system, controls the liquid supply pump 701 to start, and pumps the spray liquid prepared in the liquid preparation tank 7 into the liquid storage tank 307. This reciprocating process is used to replace the spray liquid, reducing manual labor.

[0036] In order to ensure that the liquid distribution box 7 distributes liquid evenly, a stirring device 702 is provided in the liquid distribution box 7 , and a liquid inlet is provided on the top of the liquid distribution box 7 and a liquid discharge port is provided on the bottom side wall.

[0037] The present invention is described in detail above through specific and preferred embodiments, but those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A laboratory acid waste gas purification treatment device with self-cleaning function, characterized in that: It comprises a fume hood (1), the fume hood (1) being connected to a spray adsorption tower (3) via a ventilation pipe (2), the spray adsorption tower (3) being connected to an air inlet of a centrifugal fan (5) via an exhaust pipe (4), and the air outlet of the centrifugal fan (5) being connected to an exhaust chimney (6); The fume hood (1) comprises an air collecting hood (101) and a workbench (103), wherein the air collecting hood (101) is arranged directly above the workbench (103); the spray adsorption tower (3) is provided with a demisting layer (301), a packing layer 1 (302) and a packing layer 2 (303) in sequence from top to bottom, and a plurality of spray heads (304) are provided directly above the packing layer 1 (302) and the packing layer 2 (303); the spray heads (304) are connected to the water outlet of an infusion pump (306) through a spray pipe (305), and the water inlet of the infusion pump (306) is connected to a liquid storage tank (307); the liquid storage tank (307) is arranged at the bottom of the spray adsorption tower (3) and is connected to the bottom of the spray adsorption tower (3).

2. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 1 is characterized by: The packing layer 1 (302) and the packing layer 2 (303) are made of Hakaideng environmentally friendly ball packing.

3. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 2 is characterized in that: The Hakaiden environmentally friendly ball filler is composed of large-diameter balls and small-diameter balls, and the ratio of the number of large-diameter balls to the number of small-diameter balls is 3:

1.

4. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 3 is characterized by: The diameter of the large-diameter ball is 76 mm, and the diameter of the small-diameter ball is 38 mm.

5. A laboratory acid waste gas purification treatment device with self-cleaning function according to claim 1 or 2, characterized in that: The demisting layer (301) uses polypropylene perforated plate corrugated filler.

6. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 1 is characterized by: A condensate collection tank (102) is provided around the bottom of the gas collecting hood (101); one end of the condensate collection tank (102) is connected to a drainage pipe (104); and a liquid collection bucket (105) is provided at the bottom of the drainage pipe (104).

7. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 1 is characterized by: A plurality of guide inclined plates (201) are arranged in the ventilation pipe (2) and are used to guide the condensed acid liquid in the ventilation pipe (2) into the spray adsorption tower (3).

8. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 1 is characterized by: A liquid discharge port (308) is provided on the side wall at the bottom of the liquid storage tank (307), and an electric valve is installed on the liquid discharge port (308). A pH detector (309) and a liquid level meter (310) are also installed on the liquid storage tank (307). A liquid inlet (311) is provided on the top of the liquid storage tank (307), and the liquid inlet (311) is connected to the water outlet of the liquid supply pump (701) through a pipeline. The water inlet of the liquid supply pump (701) is connected to the liquid distribution tank (7).

9. The laboratory acid waste gas purification treatment device with self-cleaning function according to claim 8 is characterized by: A stirring device (702) is provided in the liquid distribution box (7).

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