Tail gas treatment device

Abstract

The application discloses a tail gas treatment device, which comprises a buffer tank for mixing tail gas; a condensing mechanism connected with the buffer tank and used for cooling and condensing the mixed tail gas; and a hydrolysis adsorption mechanism located downstream of the condensing mechanism and comprising a tank body with a containing cavity and a gas outlet connected with each other, an acidic hydrolysis liquid arranged in the containing cavity, the acidic hydrolysis liquid being capable of promoting hydrolysis of part of the tail gas, and an activated carbon adsorbent arranged in the containing cavity and at least partially immersed in the acidic hydrolysis liquid, the tank body further comprising a gas inlet pipeline, a gas inlet end of the gas inlet pipeline being connected with the condensing mechanism, and a gas outlet end of the gas inlet pipeline being located in the acidic hydrolysis liquid and below the activated carbon adsorbent. The tail gas treatment device has the advantages of improving the treatment efficiency of the tail gas and being high in safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical equipment, in particular to a tail gas treatment device. BACKGROUND

[0002] The existing industrial waste gas treatment principles include activated carbon adsorption method, catalytic combustion method, catalytic oxidation method, acid-base neutralization method, biological washing, biological trickling filter method, plasma method and the like.

[0003] There are many types of industrial waste gas, and therefore, for the corresponding industrial waste gas (which can also be referred to as tail gas or industrial tail gas), taking the tail gas generated in the process of producing electronic-grade tetraethyl orthosilicate (TEOS) as an example, if only the above waste gas treatment technology is simply adopted, there will be problems such as poor tail gas effect, high cost, low efficiency and the like, and the tail gas cannot be effectively treated.

[0004] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be taken as an acknowledgement or any form of suggestion that this information forms prior art that is publicly known. SUMMARY

[0005] The present application aims to provide a tail gas treatment device which can improve the treatment efficiency of tail gas and has high safety.

[0006] To achieve the above-mentioned purpose, the embodiments of the present application provide a tail gas treatment device, comprising:

[0007] A buffer tank for mixing tail gas;

[0008] A condensing mechanism connected with the buffer tank for cooling and condensing the mixed tail gas;

[0009] A hydrolysis adsorption mechanism located downstream of the condensing mechanism, the hydrolysis adsorption mechanism comprising a tank body, the tank body having a containing cavity and a gas outlet connected therewith, the containing cavity being provided with an acidic hydrolysis liquid, the acidic hydrolysis liquid being capable of promoting the hydrolysis of part of the tail gas, the containing cavity of the tank body being further provided with an activated carbon adsorbent, at least part of the activated carbon adsorbent being immersed in the acidic hydrolysis liquid, the tank body further comprising a gas inlet pipeline, the gas inlet end of the gas inlet pipeline being connected with the condensing mechanism, the gas outlet end of the gas inlet pipeline being located in the acidic hydrolysis liquid and below the activated carbon adsorbent, and the gas outlet of the tank body being located above the liquid level of the acidic hydrolysis liquid and the activated carbon adsorbent.

[0010] In one or more embodiments of the present application, a fixing cage is installed on the inner wall of the tank body, at least partially immersed in the acidic hydrolysis solution, and has an inner cavity for placing the activated carbon adsorbent, and a plurality of communication holes are arranged on the fixing cage and communicate with the inner cavity, and the acidic hydrolysis solution can flow into the inner cavity through the communication holes.

[0011] In one or more embodiments of the present application, the acidic hydrolysis solution is a dilute hydrochloric acid solution.

[0012] In one or more embodiments of the present application, the condensing mechanism comprises a plurality of condensers arranged in series.

[0013] In one or more embodiments of the present application, the gas inlet pipeline has a plurality of gas outlet ends arranged at intervals.

[0014] In one or more embodiments of the present application, the tail gas treatment device further comprises a first adsorption mechanism arranged between the condensing mechanism and the hydrolysis adsorption mechanism, and the first adsorption mechanism is provided with a first adsorbent for purifying tail gas.

[0015] In one or more embodiments of the present application, the tail gas treatment device comprises two first adsorption mechanisms arranged in parallel.

[0016] In one or more embodiments of the present application, the tail gas treatment device comprises a desorption device and a gas inlet device, one end of the desorption device communicates with the buffer tank, and the other end communicates with the first adsorption mechanism; the desorption device is used for desorption treatment of the first adsorbent in the first adsorption mechanism, and the gas obtained by the desorption treatment is injected into the buffer tank;

[0017] In the process of desorption treatment of the first adsorbent in the first adsorption mechanism by the desorption device, the gas inlet device injects protective gas into the first adsorption mechanism.

[0018] In one or more embodiments of the present application, a cooler is arranged between the desorption device and the buffer tank to condense and recover part of the organic matter.

[0019] In one or more embodiments of the present application, the tail gas treatment device further comprises a second adsorption mechanism arranged downstream of the hydrolysis adsorption mechanism, and the second adsorption mechanism is provided with a second adsorbent for purifying tail gas.

[0020] Compared with the prior art, the tail gas treatment device according to the embodiments of the present application has the following beneficial effects:

[0021] (1) First, the buffer tank is used to mix the tail gas, so that the concentration of each gas in the tail gas is stabilized, facilitating subsequent treatment.

[0022] (2) By condensing part of the organic matter into liquid state through the condensing mechanism, the concentration of harmful gas in the tail gas that needs to be treated is reduced, the pressure of the subsequent treatment mechanism is also reduced, and part of the organic matter can be recovered, thereby improving the utilization efficiency of the tail gas.

[0023] (3) By using the acidic hydrolysis solution in the hydrolysis adsorption mechanism to promote the hydrolysis of the harmful gas (such as part of the organic matter) in the tail gas that needs to be treated to generate liquid and / or solid substances, the liquid and / or solid substances are more easily recovered, and the tail gas is further adsorbed by the activated carbon adsorbent, so that the harmful gas in the tail gas that needs to be treated is continuously adsorbed by the activated carbon adsorbent, thereby making the tail gas meet the discharge standard.

[0024] (4) Since the activated carbon adsorbent is partially immersed in the acidic hydrolysis solution, the principle of increased adsorption of activated carbon adsorbent under acidic conditions is used to increase the treatment efficiency of the tail gas treatment device of the present application and to reduce the adsorption cost.

[0025] (5) Since the temperature of the tail gas is relatively low after passing through the condensing mechanism, that is, after the tail gas enters the hydrolysis adsorption mechanism and contacts the activated carbon adsorbent, the activated carbon adsorbent can be at a relatively low temperature when adsorbing the harmful gas, and the principle of higher adsorption efficiency of activated carbon adsorbent at low temperature is used to improve the treatment efficiency of the tail gas and reduce the adsorption cost. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of a tail gas treatment device according to an embodiment of the present application;

[0027] Figure 2 is a sectional view of a hydrolysis adsorption mechanism according to an embodiment of the present application.

[0028] MAIN REFERENCE NUMERALS:

[0029] 1, buffer tank; 2, condensing mechanism; 21, first-stage condenser; 22, second-stage condenser; 3, hydrolysis adsorption mechanism; 31, tank body; 311, containing cavity; 312, gas outlet; 313, gas inlet pipeline; 3131, gas outlet end; 32, acidic hydrolysis solution; 33, activated carbon adsorbent; 34, fixed cage; 341, inner cavity; 342, communication hole; 4, first adsorption mechanism; 5, desorption device; 6, gas inlet device; 7, cooler; 8, second adsorption mechanism. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present application is not limited by the specific embodiments.

[0031] Unless otherwise expressly provided herein, the term "comprising" or variations such as "comprise" or "comprises" shall not be construed to be limiting in that it does not exclude the presence of additional elements or other components.

[0032] The inventors have found that a lot of waste gas is generated in the production of TEOS (tetraethyl orthosilicate). For example, cylinder flushing waste gas and unloading area waste gas, because the process of each manufacturer producing TEOS is the same or different, the harmful components that need to be treated in the waste gas generated by each manufacturer are different and / or the concentration is different. The harmful components will be different under different standards. For example, when the waste gas is treated and then discharged into the atmosphere, the amount of harmful components in the treated waste gas must meet the emission standard, and the specific components or substances included in the harmful components are also determined according to the emission standard.

[0033] For example, the components in the cylinder flushing waste gas and the unloading area waste gas can include tetraethyl orthosilicate, ethanol, diethyl ether, and nitrogen, wherein tetraethyl orthosilicate, ethanol, and diethyl ether are harmful components that need to be treated.

[0034] The existing conventional tail gas or waste gas treatment methods each have their own advantages and disadvantages, for example:

[0035] (1) Masking method. Stronger aromatic odor is mixed with the tail gas to mask the tail gas so that it can be accepted by people. It is suitable for occasions where low-concentration tail gas needs to be immediately and temporarily eliminated.

[0036] (2) Dilution diffusion method. The tail gas is discharged into the atmosphere through a chimney or diluted with non-toxic and harmless gas to reduce the concentration of the tail gas. Disadvantages: susceptible to weather conditions, tail gas substances still exist.

[0037] (3) Thermal combustion method and catalytic combustion method. The tail gas substances are fully mixed with fuel gas at high temperature to achieve complete combustion. Disadvantages: equipment is prone to corrosion, consumes fuel, high treatment cost, and easy to form secondary pollution.

[0038] (4) Water absorption method. Utilizing the characteristics that some substances in the tail gas are easily soluble in water, the odor components are directly contacted with water to dissolve in water to achieve the purpose of removing the tail gas. Disadvantages: low purification efficiency, should be used in combination with other technologies, and the tail gas must be dissolved in water.

[0039] (5) Liquid medicine absorption method. Utilizing the characteristics that some substances in the tail gas and the liquid medicine produce chemical reactions to remove some tail gas components. Disadvantages: low purification efficiency, consumes absorbent, and easy to form secondary pollution.

[0040] It can be understood that the exhaust gas produced in the process of producing TEOS (tetraethyl orthosilicate, also known as tetraethoxysilane) in various cases is mostly composed of tetraethyl orthosilicate, and therefore the above-mentioned solutions are not good for treating the exhaust gas produced in the process of producing TEOS (tetraethyl orthosilicate) (such as cylinder flushing exhaust gas and unloading area exhaust gas), and cannot effectively remove harmful components in the tail gas.

[0041] As shown in Figure 1 and 2 The tail gas treatment device according to the preferred embodiment of the present application comprises a buffer tank 1, a condensing mechanism 2, and a hydrolysis adsorption mechanism 3. The buffer tank 1 is used to mix the tail gas. The condensing mechanism 2 is connected to the buffer tank 1 and is used to cool and condense the mixed tail gas. The hydrolysis adsorption mechanism 3 is located downstream of the condensing mechanism 2. The hydrolysis adsorption mechanism 3 comprises a tank body 31, which has a containing cavity 311 and a gas outlet 312 connected thereto. The containing cavity 311 is provided with an acidic hydrolysis liquid 32, which can promote the hydrolysis of part of the tail gas. The containing cavity 311 of the tank body 31 is also provided with an activated carbon adsorbent 33, at least part of which is immersed in the acidic hydrolysis liquid 32. The tank body 31 further comprises a gas inlet pipeline 313, the gas inlet end of which is connected to the condensing mechanism 2, and the gas outlet end 3131 of which is located in the acidic hydrolysis liquid 32 and below the activated carbon adsorbent 33. The gas outlet 312 of the tank body 31 is located above the liquid level of the acidic hydrolysis liquid 32 and the activated carbon adsorbent 33.

[0042] It should be noted that the acidic hydrolysis liquid 32 in the hydrolysis adsorption mechanism 3 promotes the hydrolysis of the harmful gases (such as part of the organic matter) in the tail gas to be treated to generate liquid and / or solid substances, which are more easily recovered. The tail gas then passes through the activated carbon adsorbent 33, and the harmful gases to be treated in the tail gas continue to be adsorbed by the activated carbon adsorbent 33, so that the tail gas meets the discharge standard.

[0043] Since part of the activated carbon adsorbent 33 is immersed in the acidic hydrolysis liquid 32, the principle of increased adsorption of activated carbon adsorbent 33 under acidic conditions is utilized, thereby increasing the treatment efficiency of the tail gas treatment device of the present application and reducing the adsorption cost.

[0044] Since the temperature of the tail gas after passing through the condensing mechanism 2 is relatively low, that is, after the tail gas enters the hydrolysis adsorption mechanism 3 and contacts the activated carbon adsorbent 33, the activated carbon adsorbent 33 can be at a relatively low temperature when adsorbing the harmful gases. The principle of higher adsorption efficiency of activated carbon adsorbent 33 at low temperature is utilized, thereby achieving the effects of improving the treatment efficiency of the tail gas and reducing the adsorption cost.

[0045] It is understood that the buffer tank 1, condensation mechanism 2, and hydrolysis adsorption mechanism 3 are connected in sequence, and the exhaust gas can flow through the buffer tank 1, condensation mechanism 2, and hydrolysis adsorption mechanism 3 in sequence, and after meeting the emission standards, it can be discharged into the atmosphere. The buffer tank 1, condensation mechanism 2, and hydrolysis adsorption mechanism 3 can be connected by connecting pipelines.

[0046] The buffer tank 1 can mix the exhaust gas evenly, so as to stabilize the concentration of each gas in the exhaust gas, which is convenient for subsequent treatment.

[0047] The condensation unit 2 condenses some organic matter into a liquid state, reducing the concentration of harmful gases that need to be treated in the exhaust gas, while also reducing the pressure on subsequent treatment units. It can also recover some organic matter, improving the utilization efficiency of the exhaust gas. The organic matter can be considered a component of the harmful gases, such as tetraethyl orthosilicate (also known as tetraethoxysilane). Generally, substances that can be condensed by the condensation unit 2 have a high concentration in the exhaust gas and a boiling point higher than the condensation temperature.

[0048] The outlet end 3131 of the inlet pipe 313 is located inside the acidic hydrolysate 32 and below the activated carbon adsorbent 33. This arrangement ensures that the exhaust gas, after passing through the outlet end 3131, preferentially contacts the acidic hydrolysate 32 before contacting the activated carbon adsorbent 33. This preferentially hydrolyzes tetraethyl orthosilicate in the exhaust gas, thereby reducing the amount of harmful gases that need to be adsorbed by the activated carbon adsorbent 33, lowering the adsorption pressure of the activated carbon adsorbent 33, and extending the operating time of this exhaust gas treatment device.

[0049] Preferably, the greater the depth and volume of the accommodating cavity 311, the better, and the greater the distance between the air outlet 3131 of the air inlet pipe 313 and the activated carbon adsorbent 33, the better.

[0050] like Figure 2 As shown, in one specific embodiment, a fixing cage 34 is installed on the inner wall of the tank 31. At least part of the fixing cage 34 is immersed in the acidic hydrolysate 32. The fixing cage 34 has an inner cavity 341 for placing the activated carbon adsorbent 33. The fixing cage 34 is provided with multiple connecting holes 342 that communicate with the inner cavity 341, allowing the acidic hydrolysate 32 to flow into the inner cavity 341 through the connecting holes 342. The fixing cage 34 serves to fix and contain the activated carbon adsorbent 33. Specifically, the fixing cage 34 can be a mesh cage, and it can be made of a material that is not corroded or dissolved by the acidic hydrolysate 32 and does not react with the acidic hydrolysate 32, such as a polymer material.

[0051] In one embodiment, the tail gas treated in the actual use of the tail gas treatment device of the present application usually contains tetraethyl orthosilicate. Although tetraethyl orthosilicate can be hydrolyzed to form ethanol and silicon dioxide in water, the hydrolysis efficiency is too low. Therefore, when the acidic hydrolysis solution 32 is a dilute hydrochloric acid solution, the hydrolysis efficiency of tetraethyl orthosilicate can be increased, thereby converting gaseous tetraethyl orthosilicate into solid and liquid impurities, and reducing the amount of harmful gases present in the tail gas.

[0052] The condensing mechanism 2 includes a plurality of condensers arranged in series. The plurality of condensers arranged in series can adopt a multi-stage cooling mode to condense the tail gas, that is, the condensing temperature of the plurality of condensers arranged in series is lowered along the flow direction of the tail gas. For example, in one embodiment of the present application, the condensing mechanism 2 can include a first condenser 21 and a second condenser 22. The condensing temperature of the first condenser 21 is -5°C, and the condensing temperature of the second condenser 22 is -30°C. In this way, large fluctuations in the condensing temperature of each condenser can be avoided, which can result in poor condensing effect. In addition, the liquid obtained after condensation (which can be considered as a liquid containing organic matter) can be transferred to a specific recovery tank.

[0053] In one embodiment, the gas inlet pipe 313 has a plurality of gas outlet ends 3131 arranged at intervals. The plurality of gas outlet ends 3131 can make the tail gas more uniformly dispersed into the containing cavity 311, increase the contact area between the tail gas and the acidic hydrolysis solution 32, and increase the hydrolysis rate of some harmful gases (such as tetraethyl orthosilicate) in the tail gas.

[0054] In one embodiment, the tail gas treatment device further includes a first adsorption mechanism 4 arranged between the condensing mechanism 2 and the hydrolysis and adsorption mechanism 3. The first adsorption mechanism 4 is provided with a first adsorbent for purifying the tail gas. The first adsorption mechanism 4 can adsorb harmful gases and impurities in the tail gas, especially some harmful gases that cannot be hydrolyzed, thereby reducing the adsorption pressure of the hydrolysis and adsorption mechanism 3. The first adsorbent can be activated carbon or other adsorbents.

[0055] Further, the tail gas treatment device comprises two first adsorption mechanisms 4 arranged in parallel. During operation of the tail gas treatment device, only one first adsorption mechanism 4 works at the same time, and the valve at the inlet of the other first adsorption mechanism 4 or the valve on the pipeline is closed, i.e. the tail gas only passes through one first adsorption mechanism 4 at the same time. When the first adsorbent in the first adsorption mechanism 4 reaches saturation, the valve at the inlet of the first adsorption mechanism 4 or the valve on the pipeline is closed, and the valve at the inlet of the other first adsorption mechanism 4 or the valve on the pipeline is opened, i.e. the tail gas enters the other first adsorption mechanism 4. Then the first adsorbent in the first adsorption mechanism 4 is replaced or desorbed, and the above steps are repeated, thereby prolonging the continuous operation time of the tail gas treatment device.

[0056] Further, the tail gas treatment device comprises a desorption device 5 and an inlet device 6. One end of the desorption device 5 is connected to the buffer tank 1, and the other end is connected to the first adsorption mechanism 4. The desorption device 5 is used for desorbing the first adsorbent in the first adsorption mechanism 4 and injecting the gas obtained by desorption into the buffer tank 1. During the process of desorbing the first adsorbent in the first adsorption mechanism 4 by the desorption device 5, the inlet device 6 injects the protective gas into the first adsorption mechanism 4.

[0057] It can be understood that the desorption device 5 desorbs the first adsorbent in the first adsorption mechanism 4 by using the negative pressure effect, and then the inlet device 6 injects the protective gas into the first adsorption mechanism 4, and then the above steps are repeated several times, i.e. the desorption process is completed. The protective gas can be nitrogen or other harmless gas to the atmosphere, and preferably the protective gas can be selected to be the same as the harmless gas (harmless gas to the atmosphere) in the tail gas. The desorption device 5 can comprise a fan (not shown in the figure).

[0058] Further, a cooler 7 is arranged between the desorption device 5 and the buffer tank 1 to condense and recover part of the organic matter. The cooler 7 condenses the harmful gas generated in the desorption process, thereby reducing the amount of harmful gas returning to the buffer tank 1.

[0059] In a specific embodiment, the tail gas treatment device further comprises a second adsorption mechanism 8 arranged downstream of the water desorption mechanism 3, and the second adsorption mechanism 8 is provided with a second adsorbent for purifying the tail gas. The tail gas enters the second adsorption mechanism 8 after the water desorption mechanism 3, and the harmful gas in the tail gas is adsorbed again, so that the tail gas meets the emission standard and can be discharged into the atmosphere. In this way, it can further ensure that the gas discharged into the atmosphere meets the emission standard, and the tail gas entering the second adsorption mechanism 8 can be detected regularly. Generally, the tail gas entering the second adsorption mechanism 8 meets the emission standard. If the tail gas entering the second adsorption mechanism 8 does not meet the emission standard, it is possible that the adsorption capacity of the previous adsorption mechanism has reached saturation, and the material of the adsorption mechanism can be checked and replaced. The second adsorbent can be activated carbon or other adsorbents.

[0060] The activated carbon adsorbent 33, the first adsorbent and the second adsorbent in the present application are all adsorbents that can be directly purchased on the market.

[0061] In any of the above embodiments, Figure 1 The arrow in the above formula indicates the flow direction of the gas.

[0062] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments are chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. An exhaust gas treatment device, characterized by, The tail gas treatment device comprises: a buffer tank for mixing tail gas; a condensing mechanism connected with the buffer tank for cooling and condensing the mixed tail gas; a hydrolysis adsorption mechanism downstream of the condensing mechanism, the hydrolysis adsorption mechanism comprising a tank body having a containing cavity and a gas outlet connected with each other in the tank body, the containing cavity being provided with an acidic hydrolysis liquid capable of hydrolyzing part of the tail gas, the tank body further comprising an activated carbon adsorbent at least partially immersed in the acidic hydrolysis liquid, the tank body further comprising a gas inlet pipeline, the gas inlet end of the gas inlet pipeline being connected with the condensing mechanism, the gas outlet end of the gas inlet pipeline being located in the acidic hydrolysis liquid and below the activated carbon adsorbent, the gas outlet of the tank body being located above the liquid level of the acidic hydrolysis liquid and the activated carbon adsorbent; wherein a fixed cage is mounted on the inner wall of the tank body, the fixed cage being at least partially immersed in the acidic hydrolysis liquid, the fixed cage having an inner cavity for placing the activated carbon adsorbent, the fixed cage being provided with a plurality of communication holes connected with the inner cavity, and the acidic hydrolysis liquid being capable of flowing into the inner cavity through the communication holes. The acidic hydrolysis liquid is a dilute hydrochloric acid solution.

2. The exhaust treatment device of claim 1, wherein, The condensing mechanism comprises a plurality of condensers arranged in series.

3. The exhaust treatment device of claim 1, wherein, The gas inlet pipeline has a plurality of spaced gas outlet ends.

4. The exhaust treatment device of claim 1, wherein, The tail gas treatment device further comprises a first adsorption mechanism arranged between the condensing mechanism and the hydrolysis adsorption mechanism, the first adsorption mechanism being provided with a first adsorbent for purifying tail gas.

5. The exhaust treatment device of claim 4, wherein, The tail gas treatment device comprises two first adsorption mechanisms arranged in parallel.

6. The exhaust treatment device of claim 4 or 5, wherein, The tail gas treatment device comprises a desorption device and a gas inlet device, one end of the desorption device being connected with the buffer tank, and the other end of the desorption device being connected with the first adsorption mechanism; the desorption device is used for desorbing the first adsorbent in the first adsorption mechanism and injecting the gas obtained by the desorption into the buffer tank; wherein the gas inlet device injects protective gas into the first adsorption mechanism during the process of desorbing the first adsorbent in the first adsorption mechanism by the desorption device.

7. The exhaust treatment device of claim 6, wherein, A cooler is arranged between the desorption device and the buffer tank to condense and recover part of the organic matter.

8. The exhaust treatment device of claim 1, wherein, The tail gas treatment device further comprises a second adsorption mechanism arranged downstream of the hydrolysis adsorption mechanism, the second adsorption mechanism being provided with a second adsorbent for purifying tail gas.

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