Exhaust gas treatment system

Abstract

This utility model provides a waste gas treatment system, belonging to the field of chemical technology, comprising a degradation unit, a heat exchange unit, and an absorption unit connected in sequence. The degradation unit includes a reaction bed for degrading waste gas; the heat exchange unit includes a heat exchanger and a heater; the heat exchanger is connected to the top of the reaction bed via an outlet duct; the heater is connected to the bottom of the reaction bed via an inlet duct; waste gas enters the heat exchanger and undergoes a first temperature increase after exchanging heat with the primary purified gas entering the heat exchanger via the outlet duct; the first-heated waste gas is then reheated by the heater and enters the reaction bed for degradation; the absorption unit includes an absorber connected to the heat exchanger via a first exhaust duct; the primary purified gas, cooled by heat exchange in the heat exchanger, enters the absorber for a second purification before being discharged. The waste gas treatment system provided by this application, through two heating and two purification processes, can effectively degrade the high concentration of volatile organic compounds in the waste gas, enabling the waste gas to meet emission standards.

Description

Technical Field

[0001] This utility model belongs to the field of chemical technology, specifically relating to a waste gas treatment system. Background Technology

[0002] Waste gas emitted from organic chemical production is often rich in high concentrations of volatile organic compounds (VOCs). Currently, most companies use incineration to treat it. However, for organic waste gas containing halogenated hydrocarbons, especially chlorinated hydrocarbons, the HCl produced by decomposition under high temperature conditions during incineration can cause a certain degree of corrosion to the incineration equipment and its pipelines, resulting in the waste gas rich in VOCs not being properly treated.

[0003] Given the current severe environmental situation, there is an urgent need to find a practical and effective method to treat the waste gas rich in high concentrations of volatile organic compounds emitted from current organic chemical production. Utility Model Content

[0004] This utility model provides a waste gas treatment system, which aims to solve the technical problem that waste gas rich in high concentration of volatile organic compounds produced as a by-product in the organic chemical production process is difficult to treat and cannot meet emission standards.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: to provide a waste gas treatment system, comprising: a degradation unit, a heat exchange unit, and an absorption unit connected in sequence by pipelines;

[0006] The degradation unit includes a reaction bed for degrading waste gas;

[0007] The heat exchange unit includes a heat exchanger and a heater connected by an air supply duct; the heat exchanger is connected to the top of the reaction bed via an air outlet duct; the heater is connected to the bottom of the reaction bed via an air inlet duct; the exhaust gas enters the heat exchanger via an air supply duct connected to the heat exchanger, and undergoes a first temperature increase after exchanging heat with the primary purified gas entering the heat exchanger via the air outlet duct; the exhaust gas, after a second temperature increase by the heater, enters the reaction bed for degradation;

[0008] The absorption unit includes an absorber, which is connected to the heat exchanger via a first exhaust duct. The primary purified gas, after being cooled by heat exchange in the heat exchanger, enters the absorber via the first exhaust duct for secondary purification and is discharged via a second exhaust duct at the top of the absorber.

[0009] In one possible embodiment, the reaction bed includes, from bottom to top, a bellows, a padding layer, a reaction layer, and a buffer layer; the outlet duct is connected to the buffer layer, and the inlet duct is connected to the bellows.

[0010] In one possible implementation, a wind distribution plate is provided between the wind box and the paving layer; the wind distribution plate is provided with a plurality of wind distribution holes; a first wind baffle is provided on the upper surface of the wind distribution plate, the first wind baffle is inclined to block the wind distribution holes, and the angle between the first wind baffle and the horizontal plane where the wind distribution holes are located is an acute angle.

[0011] In one possible implementation, a screen is further provided on the upper surface of the air distribution plate, and the external dimensions of the screen are the same as those of the air distribution plate; wherein, the screen is fixed to the first wind baffle plate, and the surface of the screen is covered with an array of ceramic rings, which constitute the padding layer.

[0012] In one possible implementation, the top of the buffer layer is provided with a plurality of second wind deflectors arranged at an angle, the second wind deflectors forming an acute angle with the horizontal plane on which the buffer layer is located.

[0013] In one possible implementation, the top of the buffer layer is further provided with a plurality of third wind deflectors with different inclination directions than the second wind deflector, and the third wind deflectors are arranged alternately with the second wind deflectors; the lower end of the third wind deflector and one of the second wind deflectors form an exhaust gap for the purified air to escape, and the upper end of the third wind deflector abuts against the upper end of another adjacent second wind deflector.

[0014] In one possible implementation, the third wind deflector is positioned at a lower vertical height than the second wind deflector.

[0015] In one possible implementation, a water supply pipe is provided at the top of the absorber.

[0016] In one possible implementation, the bottom of the reaction bed is provided with a drainage pipe for discharging the liquid water collected within the reaction bed.

[0017] In one possible implementation, a hybrid air duct is also included, one end of which is connected to both an air duct and an exhaust gas duct, and the other end of which is connected to the air supply duct via a blower.

[0018] The waste gas treatment system provided by this utility model has the following advantages compared with the prior art: The concept of this application is that the waste gas and the primary purified gas that has been degraded and heated in the reaction bed exchange heat in a heat exchanger to achieve primary heating of the waste gas and cooling of the primary purified gas, so as to make full use of the heat in the system; the primary heated waste gas is then heated again by a heater to achieve secondary heating, and the waste gas after secondary heating by the heater enters the reaction bed along the air inlet pipe, and obtains primary purified gas after catalytic degradation at 400℃. The primary purified gas is introduced into the heat exchanger through the air outlet pipe, and after exchanging heat again with the waste gas entering the heat exchanger to cool down, it enters the absorber through the first exhaust pipe, reacts with potassium bicarbonate absorbent liquid in the absorber to achieve secondary purification, and overflows from the top of the absorber through the second exhaust pipe to obtain qualified emission gas.

[0019] By heating and purifying the exhaust gas twice, the high concentration of volatile organic compounds in the exhaust gas can be effectively degraded, enabling the exhaust gas to meet emission standards and solving the technical problem of treating exhaust gas rich in high concentrations of volatile organic compounds.

[0020] This application utilizes the heat generated by the degradation in the reaction bed to preheat the waste gas, while also reducing the heat of the primary purified gas. This recycling of the system's own heat also has the effect of energy saving and consumption reduction. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the waste gas treatment system provided in an embodiment of the present utility model;

[0022] Figure 2 This is a schematic diagram of the structure of the degradation unit provided in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of the heat exchange unit provided in an embodiment of the present utility model;

[0024] Figure 4 This is a schematic diagram of the main structure of the absorption unit provided in an embodiment of the present utility model;

[0025] Figure 5 A schematic diagram of the elevation structure of the air distribution plate and the first wind baffle provided in an embodiment of this utility model;

[0026] Figure 6 A top view of the air distribution holes on the air distribution plate provided in an embodiment of this utility model;

[0027] Figure 7 A side view of the first baffle plate and air distribution hole on the air distribution plate provided in the embodiment of this utility model;

[0028] Figure 8A schematic diagram of the elevation structure of the second and third windbreaks on the buffer layer provided in this embodiment of the utility model;

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Degradation Unit; 11. Reaction Bed; 111. Buffer Layer; 112. Reaction Layer; 113. Bedding Layer; 114. Air Box; 115. Second Pressure Gauge; 116. First Thermometer; 117. Second Thermometer; 118. First Pressure Gauge; 119. Third Thermometer; 120. Drain Valve; 121. Fourth Thermometer; 122. Air Inlet Pipe; 123. Drain Pipe; 124. Air Outlet Pipe; 125. Air Distribution Plate; 126. Air Distribution Hole; 127. First Baffle Plate; 128. Screen; 1111. Second Baffle Plate; 1112. Third Baffle Plate; 1113. Exhaust Gap; 2. Heat Exchange Unit; 21. Heater; 22. Heat Exchanger; 23. Blower; 212. Fifth Thermometer; 221. Air Supply Pipeline 222. Sixth thermometer; 223. First exhaust duct; 224. First VOC detector; 225. Second supply air duct; 226. First flow meter; 227. Flame arrester; 231. Mixing air duct; 232. Second VOC detector; 233. First regulating valve; 234. Air duct; 235. Second flow meter; 236. Second regulating valve; 237. Exhaust gas duct; 238. Emergency vent valve; 239. Emergency vent duct; 3. Absorption unit; 31. Absorber; 311. Third VOC detector; 312. Online pH meter; 313. Third pressure gauge; 314. Water supply duct; 315. Water supply valve; 316. Fourth VOC detector; 317. Second exhaust duct; 318. Fourth pressure gauge. Detailed Implementation

[0031] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0032] Unless otherwise expressly defined, the use of terms such as "first," "second," or "third" in the claims, description, and drawings of this utility model is for distinguishing different objects and not for describing a specific order.

[0033] Please see Figures 1 to 8The waste gas treatment system provided by this utility model will now be described. The waste gas treatment system includes: a degradation unit 1, a heat exchange unit 2, and an absorption unit 3 connected sequentially by pipelines; the degradation unit 1 includes a reaction bed 11 for degrading waste gas; the heat exchange unit 2 includes a heat exchanger 22 and a heater 21 connected by an air supply pipeline 221; the heat exchanger 22 is connected to the top of the reaction bed 11 via an air outlet pipeline 124; the heater 21 is connected to the bottom of the reaction bed 11 via an air inlet pipeline 122; the waste gas enters the system via an air supply pipeline 225 connected to the heat exchanger 22. The heat exchanger 22 exchanges heat with the primary purified gas entering the heat exchanger 22 through the outlet duct 124 and then undergoes a primary heating. The primary heated waste gas is then heated a second time by the heater 21 and enters the reaction bed 11 for degradation. The absorption unit 3 includes an absorber 31, which is connected to the heat exchanger 22 through the first exhaust duct 223. The primary purified gas, after being cooled by heat exchanger 22, enters the absorber 31 through the first exhaust duct 223 for secondary purification and is discharged through the second exhaust duct 317 at the top of the absorber 31.

[0034] The waste gas treatment system provided by this utility model has the following advantages compared with the prior art: The concept of this application is that the waste gas and the primary purified gas that has been degraded and heated by the reaction bed 11 exchange heat in the heat exchanger 22 to achieve primary heating of the waste gas and cooling of the primary purified gas, so as to make full use of the heat in the system; the primary heated waste gas is then heated by the heater 21 to achieve secondary heating, and the waste gas after secondary heating by the heater 21 enters the reaction bed 11 along the air inlet pipe 122, and obtains primary purified gas after catalytic degradation at 400℃. The primary purified gas is introduced into the heat exchanger 22 through the air outlet pipe 124, and after exchanging heat and cooling with the waste gas entering the heat exchanger 22 again, it enters the absorber 31 through the first exhaust pipe 223. In the absorber 31, it reacts with potassium bicarbonate absorption liquid to achieve secondary purification, and overflows from the top of the absorber 31 through the second exhaust pipe 317 to obtain qualified emission gas.

[0035] By heating and purifying the exhaust gas twice, the high concentration of volatile organic compounds in the exhaust gas can be effectively degraded, enabling the exhaust gas to meet emission standards and solving the technical problem of treating exhaust gas rich in high concentrations of volatile organic compounds.

[0036] This application utilizes the heat generated by the degradation of the reaction bed 11 to preheat the waste gas, while also reducing the heat of the primary purified gas. This recycling of the system's own heat also has the effect of energy saving and consumption reduction.

[0037] In some embodiments, see Figure 1 and Figure 2The reaction bed 11 includes, from bottom to top, a bellows 114, a padding layer 113, a reaction layer 112, and a buffer layer 111. An outlet duct 124 is connected to the buffer layer 111, and an inlet duct 122 is connected to the bellows 114. After being heated a second time by the heater 21, the exhaust gas enters the bellows 114 at the bottom of the reaction bed 11 along the inlet duct 122. It is then evenly distributed through the air distribution holes 126 on the air distribution plate 125 and introduced into the reaction layer 112 through the padding layer 113. In the reaction layer 112, it undergoes catalytic degradation at 400°C to obtain primary purified gas, which overflows from the top of the reaction bed 11 through the buffer layer 111.

[0038] To enable real-time and accurate monitoring of the reaction temperature within reaction chamber 112 and the gas temperature in each pipeline, allowing for timely adjustments and better reaction results, this application incorporates multiple thermometers. (See also...) Figure 2 , Figure 3 , Figure 4 As shown, a first thermometer 116 and a second thermometer 117 are provided in the reaction layer 112. The ends of the first thermometer 116 and the second thermometer 117 extend to the center of the reaction layer 112 for real-time monitoring of the temperature at the center of the reaction layer 112. At the same time, a third thermometer 119 is provided on the air outlet duct 124 connecting the reaction bed 11 and the heat exchanger 22, a fourth thermometer 121 is provided on the air inlet duct 122 connecting the heater 21 and the reaction bed 11, a fifth thermometer 212 is provided on the air supply duct 221 connecting the heat exchanger 22 and the heater 21, and a sixth thermometer 222 is provided on the first exhaust duct 223 connecting the heat exchanger 22 and the absorber 31 for real-time monitoring of the gas temperature on the corresponding ducts.

[0039] Before entering the waste gas treatment system provided in this application, the raw material waste gas rich in high concentrations of volatile organic compounds is diluted with air to control the concentration of volatile organic compounds in the mixed gas to be below 5000 mg / m³. 3 Within this range, the mixed gas of this concentration exchanges heat with the primary purified gas overflowing from the top of the reaction bed 11 before entering the reaction bed 11, thereby raising the temperature of the mixed gas. The operating load of the heater 21 is determined by the temperature data displayed by the fifth thermometer 212. The higher the temperature displayed by the fifth thermometer 212, the lower the operating load of the heater 21, and vice versa. This ensures that the waste gas reaches the expected reaction temperature when entering the reaction bed 11, thereby improving the reaction effect of the waste gas in the reaction bed 11.

[0040] The temperature of the gas mixture, after being heated a second time by heater 21, is monitored a second time by the temperature data displayed on the fourth thermometer 121, which also determines the on / off status of heater 21. In this application, heater 21 is a variable frequency thyristor electric heater 21. The frequency converter switch of heater 21 is linked to the fourth thermometer 121 for control. When the temperature of the fourth thermometer 121 reaches the set temperature, heater 21 stops working; otherwise, it continues to heat the gas mixture.

[0041] The mixed gas, which has been heated twice by heater 21, passes through air box 114 and padding layer 113 along air inlet pipe 122 and enters reaction layer 112. Since the particulate catalyst filled in reaction layer 112 can withstand high temperature of 450℃, and the high concentration of volatile organic compounds entrained in the mixed gas will release a certain amount of heat when the chemical bonds are broken under high temperature conditions, the operation of reaction layer 112 is monitored in real time by the data displayed by first thermometer 116 and second thermometer 117. Under the premise of ensuring that the mixed gas is effectively degraded, the activity of particulate catalyst is not affected by excessive temperature.

[0042] In this application, the reaction layer 112 is 800mm high, the first thermometer 116 is installed at a height of 300mm from the top of the reaction layer 112, and the second thermometer 117 is installed at a height of 500mm from the top of the reaction layer 112, so as to achieve all-round monitoring of the operation of the reaction layer 112 at all locations.

[0043] The purified gas obtained after treatment in reaction layer 112 is introduced into heat exchanger 22 through outlet duct 124 via buffer layer 111. The temperature of the primary purified gas is monitored by a third thermometer 119 installed on outlet duct 124, which can further determine the operation of reaction layer 112 and ensure the activity of granular activated carbon within reaction layer 112. The purified gas exchanges heat with the raw material mixture in heat exchanger 22, further reducing its temperature. The temperature of the primary purified gas is closely monitored by a sixth thermometer 222, ensuring that the operating temperature of the sixth thermometer 222 is controlled above 110℃. This prevents the primary purified gas temperature from being too low, which could lead to the liquefaction and corrosion of the first exhaust duct 223 by entrained water vapor. Therefore, this method can avoid or mitigate the corrosion problem of the conveying pipeline caused by the waste gas incineration method.

[0044] In addition, multiple pressure gauges are installed on the processing system, see [link / reference] Figure 2 and Figure 4As shown, a first pressure gauge 118 is installed on the side of the wind box 114, a second pressure gauge 115 is installed on the side of the buffer layer 111, a third pressure gauge 313 is installed on the first exhaust duct 223 connecting the heat exchanger 22 and the absorber 31, and a fourth pressure gauge 318 is installed on the top of the absorber 31. These are used to monitor the pressure of the reaction layer 112 and the absorber 31 in real time. When the difference between the first pressure gauge 118 and the second pressure gauge 115 is higher than 2.0 kPa, the reaction bed 11 needs to be inspected. When the values ​​displayed by the third pressure gauge 313 and the fourth pressure gauge 318 are higher than 2.0 kPa, the water supply valve 315 on the water supply duct 314 is opened to start flushing the demister inside the absorber 31 to avoid affecting the absorption effect of the absorber 31.

[0045] In some embodiments, see Figure 1 , Figure 2 , Figures 5 to 7 A wind distribution plate 125 is provided between the wind box 114 and the paving layer 113; a plurality of wind distribution holes 126 are provided on the wind distribution plate 125; a first wind baffle 127 is provided on the upper surface of the wind distribution plate 125, the first wind baffle 127 is inclined to block the wind distribution holes 126, and the angle between the first wind baffle 127 and the horizontal plane where the wind distribution holes 126 are located is an acute angle.

[0046] For example, the air distribution holes 126 are rectangles of 10mm × 5mm, evenly distributed on the horizontal plane of the air distribution plate 125, and the center distance between two adjacent air distribution holes 126 is 15mm; the angle α between the first baffle plate 127 and the horizontal plane of the air distribution holes 126 is 45°, the lower end of the first baffle plate 127 is fixed along one side of the air distribution hole 126, and the orthographic projection of the first baffle plate 127 on the air distribution plate 125 overlaps with the air distribution hole 126, and the size enclosed by its orthographic projection is the same as the size of the air distribution hole 126.

[0047] A first baffle plate 127 is installed on the air distribution hole 126 of the air distribution plate 125. It can play a strong buffering role after the high-speed mixed gas delivered by the blower 23 enters the air box 114 through the air inlet pipe 122. It can effectively reduce the strong impact of the high-speed mixed gas on the particulate catalyst in the reaction layer 112, so as to prevent the generated catalyst powder from clogging the reaction layer 112 and affecting the treatment effect of the waste gas.

[0048] In some embodiments, a screen 128 is also provided on the upper surface of the air distribution plate 125, and the external dimensions of the screen 128 are the same as those of the air distribution plate 125; wherein, the screen 128 is fixed on the first wind baffle plate 127, and the surface of the screen 128 is covered with an array of ceramic rings, which constitute a padding layer 113.

[0049] Exemplarily, cylindrical ceramic rings with a thickness of 10 mm - 20 mm are laid flat on the surface of the screen 128. The cylindrical ceramic rings form the paving layer 113 in this application, which mainly plays a great supporting role for the granular catalyst in the reaction layer 112, so as to prevent the granular catalyst from falling into the air box 114 along the air distribution holes 126, resulting in the loss of the granular catalyst.

[0050] In some embodiments, refer to Figure 8 As shown, a plurality of second windshields 1111 arranged obliquely are provided on the top of the buffer layer 111. The included angle between the second windshields 1111 and the horizontal plane where the buffer layer 111 is located is an acute angle. Exemplarily, the included angle between the second windshields 1111 and the horizontal plane where the buffer layer 111 is located is 45°. The primary purified gas overflowing from the top of the reaction layer 112 enters the buffer layer 111. Through the blocking of the second windshields 1111, the wind speed of the primary purified gas overflowing from the top of the reaction layer 112 can be buffered, so as to prevent the catalyst powder from being entrained into the subsequent heat exchanger 22, affecting the heat exchange effect of the waste gas.

[0051] In some embodiments, refer to Figure 8 As shown, a plurality of third windshields 1112 with different inclined directions from the second windshields 1111 are also provided on the top of the buffer layer 111. The third windshields 1112 and the second windshields 1111 are arranged alternately (the second windshields 1111 and the third windshields 1112 form a shape similar to the Chinese character '入' in pairs); the third windshields 1112 are located between two adjacent second windshields 1111. The upper end of the third windshield 1112 abuts against the upper end of one of the second windshields 1111, and an exhaust gap 1113 for the purified gas to escape is formed between the lower end of the third windshield 1112 and the other second windshield 1111. Exemplarily, the included angle between the third windshields 1112 and the horizontal plane where the buffer layer 111 is located is also 45°.

[0052] The primary purified gas overflowing from the top of the reaction layer 112 enters the buffer layer 111 and escapes through the exhaust gap 1113 formed by the end of the second windshield 1111 and the plane of the third windshield 1112, and enters the air outlet pipeline 124. The setting of the second windshields 1111 and the third windshields 1112 can further buffer the wind speed of the primary purified gas escaping from the top of the reaction layer 112, so as to prevent the catalyst powder from being entrained into the subsequent heat exchanger 22, affecting the heat exchange effect of the waste gas.

[0053] In some embodiments, refer to Figure 8As shown, the height of the third wind deflector 1112 in the up-down direction is lower than that of the second wind deflector 1111 in the up-down direction. Generally speaking, the width of the second wind deflector 1111 is greater than that of the third wind deflector 1112, so that the second wind deflector 1111 and the third wind deflector 1112 form a shape similar to the Chinese character "Ru" pairwise. The second wind deflector 1111 plays a guiding role in the formed primary purified gas. Through the guidance of the second wind deflector 1111, the primary purified gas is guided to escape from the exhaust gap 1113.

[0054] In some embodiments, refer to Figure 1 and Figure 4 As shown, a water supply pipeline 314 is provided at the top of the absorber 31. A water supply valve 315 is provided on the water supply pipeline 314. When the pressure of the primary purified gas entering the absorber 31 is higher than the pressure of the discharged secondary purified gas, the water supply valve 315 needs to be opened to start flushing the demister inside the absorber 31 to avoid affecting the absorption effect of the absorber 31.

[0055] In some embodiments, refer to Figure 1 and Figure 2 , a drain pipeline 123 for discharging the liquid water collected in the reaction bed 11 is provided at the bottom of the reaction bed 11. Specifically, a drain pipeline 123 is provided at the bottom of the air box 114, and a drain valve 120 is provided on the drain pipeline 123.

[0056] When using the waste gas treatment system provided by the present application to treat waste gas rich in high-concentration volatile organic compounds, since the carbon in the organic matter entrained in the waste gas is converted into carbon dioxide, chlorine is converted into hydrogen chloride and a small amount of chlorine gas, and hydrogen is converted into water. When the system cools down and stops, the residual gas in the waste gas treatment system, especially in the reaction bed 11, due to the temperature drop, the water vapor entrained in the waste gas will be converted into liquid water. The liquid water will show a certain acidity due to containing a small amount of hydrogen chloride or chlorine gas. After the system stops stably, open the drain valve 120 on the drain pipeline 123 to discharge the liquid water collected in the air box 114 to avoid the liquid water accumulating at the bottom of the air box 114 for too long and causing equipment corrosion.

[0057] In some embodiments, refer to Figure 1 and Figure 3 , the waste gas treatment system further includes a mixed air pipeline 231. One end of the mixed air pipeline 231 is connected to the air pipeline 234 and the waste gas pipeline 237, and the other end of the mixed air pipeline 231 is connected to the second air supply pipeline 225 through a blower 23.

[0058] Specifically, the air duct 234 is equipped with a first regulating valve 233 for real-time regulation of the air intake to maintain the reaction temperature of the reaction layer 112; the exhaust gas duct 237 is equipped with a second regulating valve 236 and a second flow meter 235. The second regulating valve 236 is used to regulate the flow rate of exhaust gas entering the treatment system when the system is turned on, and the second flow meter 235 is used to monitor the flow rate of exhaust gas in real time; the air supply duct 225 connecting the blower 23 and the heat exchanger 22 is also equipped with a first flow meter 226 for real-time monitoring of the flow rate of the mixed gas.

[0059] See Figure 1 , Figure 3 , Figure 4 As shown, a second VOC detector 232 is installed on the mixing air duct 231, a first VOC detector 224 is installed on the air supply duct 225 connecting the blower 23 and the heat exchanger 22, a third VOC detector 311 is installed on the first exhaust air duct 223 connecting the heat exchanger 22 and the absorber 31, and a fourth VOC detector 316 is installed on the top of the absorber 31. These are used to monitor in real time the concentration of volatile organic compounds (rich in non-methane total hydrocarbons) in the exhaust gas of the corresponding ducts. At the same time, the first VOC detector 224 and the second VOC detector 232 are respectively linked to the first regulating valve 233 for control. The raw material waste gas emitted from organic chemical industry is mixed and diluted with the air introduced by air pipe 234 through waste gas pipe 237 in a certain proportion. According to the data displayed by the first VOC detector 224 and the second VOC detector 232, the air intake volume is adjusted in real time through the first regulating valve 233 to prevent the concentration of volatile organic compounds entrained in the mixed gas from being too high, which would affect the catalytic degradation effect of the reaction layer 112 in the reaction bed 11.

[0060] The technical solution provided in this application is designed to handle an air volume of 18000 Nm³. 3 / h, volatile organic compound concentration controlled at 5000 mg / m³ 3 Within. Capable of handling an air volume of 18000 Nm³. 3 Taking / h as an example, under the condition that the frequency conversion opening degree of the blower 23 remains unchanged, if either the displayed data of the first VOC detector 224 or the second VOC detector 232 is higher than 5000mg / m³, 3 When the temperature of the reaction layer 112 is too high, the opening degree of the first regulating valve 233 is increased to reduce the concentration of volatile organic compounds in the mixture, so as to prevent the reaction layer 112 from becoming too hot and affecting the reaction activity of the particulate catalyst; when the VOC data displayed by the first VOC detector 224 and the second VOC detector 232 are both below 5000 mg / m³ 3 When this happens, the opening degree of the first regulating valve 233 will be slowly reduced.

[0061] The purified gas overflowing from the top of the reaction bed 11 is monitored in real time by the third VOC detector 311 installed on the first exhaust duct 223, which ensures the operating effect of the reaction layer 112. At the same time, the data displayed by the fourth VOC detector 316 installed on the top of the absorber 31 is used to calibrate the third VOC detector 311 in real time, and further determine whether the purified gas discharged from the second exhaust duct 317 on the top of the absorber 31 can meet the emission standards.

[0062] Specifically, an emergency venting pipe 239 is also provided on the exhaust gas pipe 237, and an emergency venting valve 238 is provided on the emergency venting pipe 239. Before the initial start-up of the exhaust gas treatment system provided in this application, the exhaust gas rich in high concentrations of volatile organic compounds emitted by the organic production system is introduced into the incineration system for treatment through the emergency venting pipe 239. When starting up the exhaust gas treatment system provided in this application, it is necessary to first confirm that the second regulating valve 236 is in the closed state, and then open the first regulating valve 233 and the blower 23. According to the data displayed by the first VOC detector 224 and the second VOC detector 232, the opening of the second regulating valve 236 is slowly increased so that the production exhaust gas is slowly incorporated into the mixing air pipe 231. After the production exhaust gas is completely incorporated into the mixing air pipe 231, the emergency venting valve 238 on the emergency venting pipe 239 is closed.

[0063] In the technical solution provided in this application, the following technical means are adopted from the perspectives of reaction effect and safe operation: First, the length of the mixing air duct 231 is 15m-20m to ensure that the air and the production waste gas rich in high concentration of volatile organic compounds are fully mixed.

[0064] Secondly, in the technical solution provided in this application, the blower 23 is a high-temperature and high-pressure resistant blower with variable frequency control; at the same time, the first thermometer 116, the second thermometer 117, the frequency converter of the blower 23, the first regulating valve 233, the second regulating valve 236, and the emergency vent valve 238 are linked for control. When the temperature display data of either the first thermometer 116 or the second thermometer 117 is higher than 430℃, the linkage control is activated, and the emergency vent valve 238 is opened, the second regulating valve 236 is closed, the first regulating valve 233 is opened to the maximum, and the frequency converter of the blower 23 is turned on to the maximum, so as to use low-temperature air to cool the reaction layer 112 in the reaction bed 11 to avoid safety problems.

[0065] In addition, in the technical solution provided in this application, a flame arrester 227 is also provided on the air supply duct 225 connecting the blower 23 and the heat exchanger 22, so as to ensure the safety and stability of the operation of the exhaust gas treatment system provided in this application.

[0066] In the technical solution provided in this application, an online pH meter 312 is provided on the lower side of the absorber 31 to monitor the pH value of the absorbent liquid in the absorber 31 in real time. When the pH value of the absorbent liquid reaches 6-7, the absorbent liquid is replaced regularly. At the same time, in the technical solution provided in this application, potassium bicarbonate aqueous solution is used as the absorbent liquid in the absorber 31. Under the premise of ensuring the effective absorption of hydrogen chloride and chlorine, carbon dioxide gas is not absorbed, which greatly reduces the consumption of alkaline absorbent liquid.

[0067] Since the absorber 31 used in the technical solution provided in this application is a conventional structure, it will not be described in detail here.

[0068] The waste gas treatment system provided by this utility model, in addition to performing two heating and two purification processes on the waste gas, also adopts the following technical means to solve the technical problem of difficult treatment of waste gas rich in high concentrations of volatile organic compounds:

[0069] First, a first baffle plate 127 is installed on the air distribution hole 126 of the air distribution plate 125 between the air box 114 and the padding layer 113. This can effectively reduce the strong impact of the high-speed transported mixed gas on the particulate catalyst in the reaction layer 112, so as to prevent the generated catalyst powder from clogging the reaction layer 112 and affecting the treatment effect of the raw material waste gas.

[0070] Secondly, the second baffle plate 1111 and the third baffle plate 1112 set on the top of the buffer layer 111 can further buffer the wind speed of the purified gas overflowing from the top of the reaction bed 11, so as to prevent the catalyst powder from being carried into the subsequent heat exchanger 22 and affecting the heat exchange effect. At the same time, the low temperature mixed gas discharged by the blower 23 and the high temperature purified gas discharged by the reaction bed 11 are effectively exchanged through the heat exchanger 22, which can make full use of the heat in the treatment system and avoid waste of resources.

[0071] Third, the primary purified gas is introduced into the absorber 31 through the exhaust pipe for secondary purification. The pressure difference between the third pressure gauge 313 on the first exhaust pipe 223 and the fourth pressure gauge 318 on the top of the absorber 31 can effectively determine the operating effect of the absorber 31. When the pressure difference value displayed by the third pressure gauge 313 and the fourth pressure gauge 318 is higher than the set value, primary water is added through the water replenishment pipe 314 set on the top of the absorber 31 to thoroughly flush the absorber 31, further ensuring the secondary purification effect of the absorber 31.

[0072] Therefore, the waste gas treatment system provided in this application can effectively degrade the high concentration of volatile organic compounds (VOCs) in the waste gas, enabling the waste gas to meet emission standards and solving the technical problem of treating waste gas rich in high concentrations of VOCs. For example, it can degrade the high concentration of non-methane total hydrocarbons (NMCH) in the waste gas, enabling the waste gas to meet emission standards and solving the technical problem of treating waste gas rich in high concentrations of NMCH.

[0073] The working principle of the waste gas treatment system provided by this utility model is as follows: the raw material waste gas emitted from organic chemical industry is mixed and diluted with the air introduced by the air pipe 234 through the waste gas pipe 237 in a certain proportion. According to the data displayed by the first VOC detector 224 and the second VOC detector 232, the air intake volume is adjusted in real time by the first regulating valve 233 to prevent the concentration of volatile organic compounds entrained in the mixed gas from being too high, which would affect the catalytic degradation effect of the reaction layer 112 in the reaction bed 11. The mixed air that has been diluted and qualified is introduced into the heat exchanger 22 through the blower 23 along the second air supply pipe 225, and exchanges heat with the primary purified gas discharged from the reaction bed 11 along the outlet air pipe 124. The system is first heated to make full use of the heat in the system. The waste gas that has been heated once is introduced into the air supply pipe along the outlet air pipe. The gas is introduced into heater 21 via air inlet 221. After secondary heating by heater 21, it enters the air box 114 at the bottom of reaction bed 11 via air inlet duct 122. Then, it is evenly distributed through air distribution holes 126 on air distribution plate 125 and introduced into reaction layer 112 via padding layer 113. In reaction layer 112, it undergoes catalytic degradation at 400℃ to obtain purified gas. The purified gas escapes from the top of reaction bed 11 through buffer layer 111 and is introduced into heat exchanger 22 via air outlet duct 124. After heat exchange and cooling with the mixed gas delivered by blower 23, it enters absorber 31 through first exhaust duct 223. In absorber 31, it reacts with potassium bicarbonate absorbent to obtain secondary purified gas. It escapes from the top of absorber 31 through second exhaust duct 317 to obtain qualified emission gas.

[0074] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0075] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A waste gas treatment system, characterized in that, include: The degradation unit (1), heat exchange unit (2) and absorption unit (3) are connected in sequence by pipelines; The degradation unit (1) includes a reaction bed (11) for degrading waste gas; The heat exchange unit (2) includes a heat exchanger (22) and a heater (21) connected by an air supply duct (221); the heat exchanger (22) is connected to the top of the reaction bed (11) through an air outlet duct (124); the heater (21) is connected to the bottom of the reaction bed (11) through an air inlet duct (122); the exhaust gas enters the heat exchanger (22) through an air supply duct (225) connected to the heat exchanger (22), and undergoes a first heating after exchanging heat with the primary purified gas entering the heat exchanger (22) through the air outlet duct (124); the exhaust gas heated once is heated a second time by the heater (21) and then enters the reaction bed (11) for degradation; The absorption unit (3) includes an absorber (31), which is connected to the heat exchanger (22) through a first exhaust duct (223). The primary purified gas, after being cooled by heat exchange in the heat exchanger (22), enters the absorber (31) through the first exhaust duct (223) for secondary purification, and is discharged through the second exhaust duct (317) at the top of the absorber (31).

2. The waste gas treatment system as described in claim 1, characterized in that, The reaction bed (11) includes a bellows (114), a padding layer (113), a reaction layer (112), and a buffer layer (111) arranged sequentially from bottom to top; the air outlet pipe (124) is connected to the buffer layer (111), and the air inlet pipe (122) is connected to the bellows (114).

3. The waste gas treatment system as described in claim 2, characterized in that, A wind distribution plate (125) is provided between the wind box (114) and the padding layer (113); a plurality of wind distribution holes (126) are provided on the wind distribution plate (125); a first wind baffle (127) is provided on the upper surface of the wind distribution plate (125), the first wind baffle (127) is inclined to block the wind distribution holes (126), and the angle between the first wind baffle (127) and the horizontal plane where the wind distribution holes (126) are located is an acute angle.

4. The waste gas treatment system as described in claim 3, characterized in that, The upper surface of the air distribution plate (125) is also provided with a screen (128), and the external dimensions of the screen (128) are the same as those of the air distribution plate (125); wherein, the screen (128) is fixed on the first wind baffle plate (127), and the surface of the screen (128) is covered with an array of ceramic rings, which constitute the padding layer (113).

5. The waste gas treatment system as described in claim 2, characterized in that, The top of the buffer layer (111) is provided with several inclined second wind deflectors (1111), and the angle between the second wind deflectors (1111) and the horizontal plane where the buffer layer (111) is located is an acute angle.

6. The waste gas treatment system as described in claim 5, characterized in that, The top of the buffer layer (111) is also provided with a plurality of third wind deflectors (1112) with different inclination directions than the second wind deflector (1111). The third wind deflectors (1112) and the second wind deflectors (1111) are arranged alternately. The lower end of the third wind deflector (1112) and one of the second wind deflectors (1111) form an exhaust gap (1113) for the purified gas to escape. The upper end of the third wind deflector (1112) abuts against the upper end of the adjacent second wind deflector (1111).

7. The waste gas treatment system as described in claim 6, characterized in that, The height of the third wind deflector (1112) in the vertical direction is lower than that of the second wind deflector (1111) in the vertical direction.

8. The waste gas treatment system as described in claim 1, characterized in that, A water supply pipe (314) is provided on the top of the absorber (31).

9. The waste gas treatment system as described in claim 1, characterized in that, The bottom of the reaction bed (11) is provided with a drainage pipe (123) for discharging the liquid water collected in the reaction bed (11).

10. The waste gas treatment system as described in claim 1, characterized in that, It also includes a mixing air duct (231), one end of which is connected to both an air duct (234) and an exhaust gas duct (237), and the other end of which is connected to the second air supply duct (225) via a blower (23).

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