In-situ regenerated co catalytic oxidation system

Abstract

This invention belongs to the field of flue gas purification technology. It discloses an in-situ regenerated CO catalytic oxidation system. By designing a catalytic bed with a rotary structure and CO and VOCs catalytic reactors with independently partitioned inlet and outlet gas chambers, it can simultaneously perform catalytic oxidation and thermal regeneration of the catalyst, achieving online in-situ catalyst regeneration. This significantly improves the efficiency of flue gas purification, effectively promotes stable catalyst circulation, and ensures efficient flue gas treatment.

Description

Technical Field

[0001] This utility model relates to flue gas purification technology, specifically to an in-situ regenerated CO catalytic oxidation system, belonging to the field of flue gas purification technology. Background Technology

[0002] VOCs in flue gas are not only pollutants that need to be removed, but also important factors contributing to high CO oxidation temperatures and CO catalyst deactivation. Benzene-based VOCs inhibit the CO reaction by competing for active oxygen and suppressing the formation of CO oxidation intermediates, thereby increasing the CO oxidation reaction temperature. The difficult-to-decompose carbonaceous byproducts formed during VOC oxidation lead to catalyst deactivation due to carbon buildup. Deactivated catalysts can be regenerated under a high-temperature oxidizing atmosphere. A high-temperature oxidizing atmosphere promotes the decomposition and desorption of carbon deposits; simultaneously, high-speed gas purging can clean physically adsorbed pollutants and dust from the catalyst surface, thus re-exposing active sites and restoring catalytic performance. In existing technologies, high-temperature regeneration of deactivated catalysts requires shutting down the reactor, cooling it down, removing the catalyst, and then heating it back to the regeneration temperature. This process is not only complex and inefficient, but also significantly reduces flue gas treatment efficiency and consumes a large amount of energy. Utility Model Content

[0003] To address the problem of low flue gas treatment efficiency caused by the need for shutdown regeneration of existing catalysts, this invention provides an in-situ regenerated CO catalytic oxidation system. By designing a CO and VOCs catalytic reactor with a rotary catalytic bed, the various catalyst units in the rotary catalytic bed can alternately cycle between purifying the flue gas and generating heat for thermal regeneration without shutting down the system. This enables continuous treatment of the flue gas and significantly improves the purification efficiency.

[0004] To achieve the above-mentioned technical objectives, the technical solution adopted by this utility model is as follows:

[0005] An in-situ regeneration CO catalytic oxidation system includes a flue gas delivery pipeline, a CO and VOCs catalytic reactor, and a clean flue gas emission pipeline connected in series. The CO and VOCs catalytic reactor includes a shell and a rotary catalytic bed. The rotary catalytic bed is installed in the inner cavity of the shell via a rotation drive mechanism. The inner cavity of the shell is divided into a reaction zone and a regeneration zone, each with its own independent inlet and outlet. The flue gas delivery pipeline is connected to the inlet of the reaction zone, which is connected to the clean flue gas emission pipeline. A clean flue gas branch pipe extends from the clean flue gas emission pipeline and connects to the inlet of the regeneration zone, while the outlet of the regeneration zone is connected to a regeneration gas exhaust pipeline. The rotation drive mechanism drives the rotary catalytic bed to rotate, causing the individual catalytic units in the rotary catalytic bed to circulate alternately between the reaction zone and the regeneration zone, thereby achieving in-situ cyclic regeneration of each catalytic unit.

[0006] Preferably, the rotary drive mechanism includes a rotary drive motor and a rotating shaft. The rotating shaft passes sequentially through the center of the housing and the rotary catalyst bed, and is movably connected to the housing via bearings, while the rotating shaft and the rotary catalyst bed are fixedly connected. The rotary drive motor is located in the housing and connected to one end of the rotating shaft.

[0007] Preferably, the CO catalytic oxidation system further includes a first heater, which is disposed on the flue gas conveying pipeline or at the gas inlet of the reaction zone.

[0008] Preferably, the CO catalytic oxidation system also includes a second heater, which is installed on the clean flue gas branch pipe or at the air inlet of the regeneration zone.

[0009] Preferably, the CO catalytic oxidation system further includes a first indirect heat exchanger, the cold medium passage of which is connected to the flue gas conveying pipeline. The hot medium passage of the first indirect heat exchanger is connected to the clean flue gas emission pipeline.

[0010] Preferably, the connection between the first indirect heat exchanger and the flue gas conveying pipe is located upstream of the first heater. The connection between the first indirect heat exchanger and the clean flue gas discharge pipe is located downstream of the clean flue gas branch pipe.

[0011] Preferably, the CO catalytic oxidation system also includes a zeolite rotor. The main flue gas delivery pipe is connected to the inlet of the zeolite rotor's adsorption zone. The exhaust port of the zeolite rotor's adsorption zone is connected to a high-carbon gas delivery pipe. The branch pipe of the raw flue gas delivery pipe is connected to the inlet of the zeolite rotor's cooling zone. The exhaust port of the zeolite rotor's cooling zone is connected to the inlet of the zeolite rotor's desorption zone via a return gas pipe. The exhaust port of the zeolite rotor's desorption zone is connected to the flue gas delivery pipe.

[0012] Preferably, the CO catalytic oxidation system also includes a decarbonization reactor, the inlet of which is connected to a high-carbon gas delivery pipeline. The exhaust port of the decarbonization reactor is connected to a decarbonized flue gas exhaust pipeline.

[0013] Preferably, the CO catalytic oxidation system further includes a second indirect heat exchanger, the cold medium channel of which is connected to the return gas pipeline. The hot medium channel of the second indirect heat exchanger is connected to the decarbonized flue gas exhaust pipeline.

[0014] As a preferred option, flue gas composition detectors are independently installed at both the air inlet and exhaust outlet of the reaction zone.

[0015] As a preferred option, temperature sensors are also installed at the air inlet and outlet of the reaction zone.

[0016] Preferably, the system of this invention may also optionally include a control device, which is connected to the other components constituting the system via wired or wireless electrical signals, and controls the operating status of the other components. Preferably, the control device is a PLC control cabinet.

[0017] In this invention, the process of CO catalytic oxidation using the CO catalytic oxidation system described herein is as follows:

[0018] 1) Flue gas containing CO and VOCs is fed into the reaction zone of a CO and VOCs catalytic reactor and subjected to catalytic oxidation using an active catalyst in a rotary catalytic bed to obtain clean flue gas. The deactivated catalyst in the rotary catalytic bed is then rotated to the regeneration zone.

[0019] 2) A portion of the clean flue gas is sent to the regeneration zone to regenerate the deactivated catalyst, obtaining a regenerated catalyst. The regenerated catalyst is then rotated into the reaction zone to participate in catalytic oxidation. Steps 1) and 2) are repeated in a cycle.

[0020] 3) Monitor the CO and VOC content in the flue gas containing CO and VOCs at the inlet of the reaction zone in real time, and adjust the temperature of the clean flue gas sent into the regeneration zone in real time according to the changes in CO and VOC content, so that the catalytic activity of the regeneration catalyst meets the operating conditions.

[0021] Preferably, the method further includes the following steps:

[0022] 4) A portion of the original flue gas is adsorbed in the adsorption zone of the zeolite rotor to obtain high-carbon flue gas, and the high-carbon flue gas is decarbonized to obtain decarbonized flue gas; the remaining portion of the original flue gas is passed through the cooling zone of the zeolite rotor and then exchanged with the decarbonized flue gas before passing through the desorption zone of the zeolite rotor to obtain the flue gas to be treated.

[0023] Preferably, in step 4), the portion of the original flue gas passing through the zeolite rotor adsorption zone accounts for 80-99% of the total volume of the original flue gas, and more preferably 90-95%.

[0024] Preferably, the temperature of the portion of purified flue gas fed into the regeneration zone is adjusted in real time based on changes in CO and VOC content. Specifically, this involves first calculating the temperature of the purified flue gas after catalytic oxidation based on changes in CO and VOC content; then, selectively heating or cooling the portion of purified flue gas fed into the regeneration zone based on the calculated temperature, ensuring that the temperature of this portion of the purified flue gas matches the target regeneration temperature. The temperature of the purified flue gas after catalytic oxidation is calculated using the following formula:

[0025] (I).

[0026] In equation (I), T j Temperature of the purified flue gas after catalytic oxidation treatment, in °C. ρ is the flue gas density, in kg / m³. 3 c is the specific heat capacity of the flue gas, kJ / (kg·K). C0 is the concentration of CO in the flue gas, g / m³. 3 C v0 The concentration of VOCs in flue gas, in g / m³ 3 y1 represents the first conversion rate, %. y2 represents the second conversion rate, %. λ2 represents the calorific value of VOCs, kJ / mol. M co M is the molar mass of CO, in g / mol. voc The value represents the molar mass of VOCs, in g / mol. The temperature of the purified flue gas after catalytic oxidation treatment is calculated in real time according to formula (I).

[0027] Preferably, the rotary catalytic bed is divided into n consecutive catalytic units based on the size of the regeneration area in the regeneration zone. When any one of the catalytic units is regenerated sequentially in the regeneration zone, the remaining (n-1) catalytic units undergo catalytic oxidation treatment in the reaction zone. Then:

[0028] (II).

[0029] (III).

[0030] In equations (II)-(III), y1(i) represents the first conversion rate during the regeneration of the i-th catalytic unit, %. y2(i) represents the second conversion rate during the regeneration of the i-th catalytic unit, %. S f The catalyst area in the reaction zone is m. 3 S z The catalyst area in the regeneration zone is m. 3K1 is the first conversion coefficient, with a value of 0.5~0.7. K2 is the second conversion coefficient, with a value of 0.75~0.85. K3 is the third conversion coefficient, with a value of 0.45~0.55. K4 is the fourth conversion coefficient, with a value of 0.60~0.70. i is an integer from 1 to n. The first conversion rate and the second conversion rate during the regeneration of any catalytic unit are calculated according to equations (II) and (III), respectively.

[0031] Preferably, the target regeneration temperature lower limit and upper limit of the regeneration zone are set to T respectively. z1 and T z2 , ℃. Then we have:

[0032] When T j <T z1 At that time, the portion of the clean flue gas sent into the regeneration zone is heated to [T]. j ,T z1 ].

[0033] When T z1 ≤T j ≤T z2 At this time, there is no need to heat or cool the portion of clean flue gas sent into the regeneration zone.

[0034] When T z2 <T j At that time, the portion of the clean flue gas sent into the regeneration zone is cooled to [T]. j ,T z1 ].

[0035] Preferably, the heating is performed using a heater, and the cooling is performed using an indirect heat exchanger.

[0036] In this invention, the CO and VOCs catalytic reactor is a rotary reactor (similar to a zeolite rotor), comprising a shell and a rotary catalytic bed installed inside the shell via a rotary drive mechanism. The inner cavity of the shell is divided into an upper regeneration zone and a lower reaction zone, each with its own independent inlet and outlet. Driven by the rotary drive mechanism, the rotary catalytic bed rotates within the shell around its center, allowing each catalytic unit to alternately circulate between the reaction and regeneration zones. The flue gas to be treated is introduced into the reaction zone and reacts with the fresh or regenerated catalyst to achieve purification. After a period of reaction, the catalytic activity of the catalyst continuously decreases until it falls below the operating requirements (i.e., it is considered deactivated). At this point, the deactivated catalytic unit is simply rotated upwards to the regeneration zone for thermal regeneration. Simultaneously, the regenerated catalytic unit in the regeneration zone rotates downwards to the reaction zone to participate in the flue gas purification process. This cycle allows for simultaneous flue gas purification and catalyst regeneration, thus achieving continuous flue gas purification.

[0037] In this invention, the rotary catalytic bed is a disc structure with a certain horizontal thickness. Its center is connected to an external rotary drive motor via a horizontal rotating shaft (i.e., the horizontal rotating shaft and the rotary drive motor together constitute the rotary drive mechanism). It should be noted that the rotary catalytic bed can be either a single, integral disc structure or a disc structure composed of multiple identical fan-shaped catalytic units sequentially assembled. Preferably, to improve the support effect on the catalytic units, a support partition is provided between any two adjacent catalytic units, with the bottom end of the support partition connected to the horizontal rotating shaft. Furthermore, to reduce the air leakage rate between the reaction zone and the regeneration zone, the support partition is in contact with the inner wall of the CO and VOCs catalytic reactor shell (but not fixedly connected; the support partition can rotate with the horizontal rotating shaft, causing each catalytic unit to rotate inside the shell, thus allowing each catalytic unit to alternately circulate between the reaction zone and the regeneration zone).

[0038] In this invention, the rotary drive mechanism drives the rotary catalyst bed to rotate either at a constant speed or at a certain rotation angle (i.e., the rotary catalyst bed is driven to rotate at a certain angle every certain time interval, for example, the rotary catalyst bed is driven to rotate 30° every 10 minutes).

[0039] In this invention, the flue gas to be treated passes through a first heater before entering the reaction zone for reaction. If the flue gas temperature does not meet the requirements of the catalytic oxidation reaction (preferably the temperature of the catalytic oxidation reaction is 250~280℃), the heater is activated to heat it, thereby effectively ensuring the efficient catalytic reaction in the reaction zone. Otherwise, it is not necessary to activate the heater.

[0040] In this invention, CO and VOCs in the flue gas release a large amount of heat after catalytic oxidation, significantly increasing the temperature of the clean flue gas. Since the flue gas contains almost no solid impurities, directly discharging this portion would result in ineffective heat utilization. Therefore, this invention extracts a portion of the clean flue gas separately and heats it through a second heater to obtain high-temperature clean flue gas. This high-temperature clean flue gas is then used as the regeneration heat source in the regeneration zone to oxidize and remove carbon deposits from the catalyst due to VOCs, and to rapidly strip adsorbed flue gas dust from the catalyst surface, thus regenerating the catalyst (preferably at a regeneration reaction temperature of 400-450°C). Compared to existing technologies that directly heat air as the regeneration heat source, this significantly reduces additional regeneration heating energy consumption, thereby significantly reducing the catalyst regeneration cost. Furthermore, the heat in the clean flue gas not used as a regeneration heat source is transferred to the untreated flue gas before heating and catalytic reaction through indirect heat exchange (i.e., the heat of the clean flue gas to be discharged is transferred to the upstream untreated flue gas through a first indirect heat exchanger), thereby achieving the recycling and utilization of the system's waste heat.

[0041] In this invention, the flue gas to be treated before entering the reaction zone (referring to the flue gas to be transported to the reactor in the flue gas conveying pipeline) can be either raw flue gas from the steel plant or flue gas from the steel plant after VOCs concentration treatment. That is, this invention also includes a zeolite rotor upstream of the flue gas conveying pipeline, comprising an adsorption zone, a cooling zone, and a desorption zone. Most of the raw flue gas is sent to the adsorption zone for VOCs adsorption (preferably at a temperature of 100-180°C) and becomes CO flue gas. The CO flue gas then undergoes catalytic removal of CO in a decarbonization reactor (i.e., a low-temperature CO reactor) (preferably at a temperature of 100-180°C), resulting in decarbonized flue gas with a certain temperature. A small portion of the raw flue gas enters the cooling zone as cooling gas, and then exchanges heat with the decarbonized flue gas to raise its temperature, serving as the carrier gas in the desorption zone, thereby carrying away the adsorbed VOCs (preferably at a temperature of 190-210°C), resulting in flue gas with high VOCs and CO content. In other words, after the raw flue gas is treated by the zeolite rotor, VOCs are enriched and CO is diverted, meaning that VOCs are basically incorporated into the flue gas to be treated.

[0042] In this invention, the temperature of the original flue gas after passing through the zeolite rotor cooling zone is relatively low, which is not conducive to the direct removal of adsorbed VOCs. Generally, the temperature of this part of the original flue gas needs to be increased before it can be used as the carrier gas for VOCs desorption. At the same time, most of the CO flue gas releases a large amount of heat after passing through the decarbonization reactor, meaning that the decarbonized flue gas carries a large amount of heat. Therefore, this invention transfers the heat in the decarbonized flue gas to the original flue gas to be used as the carrier gas for VOCs desorption by adding a second indirect heat exchanger. This achieves the recycling of the decarbonized flue gas in the system on the one hand, and eliminates the need for additional heating devices on the other hand, reducing heating energy consumption and thus reducing system operating costs.

[0043] In this invention, each catalytic unit of the rotary catalytic bed enters the regeneration zone one by one for regeneration. That is, after one catalytic unit is regenerated, the rotary catalytic bed rotates, allowing the next catalytic unit to enter the regeneration zone, while the total number of catalytic units in the reaction zone remains constant. Although the number of catalytic units in the reaction zone remains constant, the overall catalytic activity of the reaction zone changes because a catalytic unit with higher catalytic activity (i.e., the catalytic unit regenerated from the regeneration zone) replaces a catalytic unit with the lowest catalytic activity (i.e., the catalytic unit entering the regeneration zone). In other words, the temperature of the clean flue gas at the outlet of the reaction zone changes with the overall recovery of the catalyst activity and the concentration of reactants. Therefore, the temperature of this portion of the clean flue gas, which serves as the regeneration heat source, needs to be continuously adjusted by a second heater. Compared to constant heating, this ensures the stability of the regeneration temperature, preventing low temperatures in the regeneration zone from leading to unsatisfactory regeneration results and preventing overheating of the regeneration zone from causing permanent catalyst deactivation. It also reduces energy waste.

[0044] In this invention, through practical research, a model for predicting the net flue gas temperature was established, using the CO and VOC content in the flue gas to be treated and the overall activity of the reactor catalyst as independent variables. Based on this model, the net flue gas temperature can be accurately calculated under different CO and VOC concentration changes and variations in the overall catalyst activity. This facilitates precise temperature regulation of the net flue gas through a heater when it is used as a regeneration heat source in the regeneration zone, ensuring it meets the catalyst regeneration requirements. Specifically, by real-time monitoring of the VOC and CO content and temperature changes in the flue gas to be treated at the inlet of the reaction zone, the temperature of the net flue gas after catalytic oxidation treatment is calculated based on the current changes in CO and VOC content, and the power of the second heater is adjusted accordingly to ensure that the temperature of this portion of the net flue gas used as a regeneration heat source in the regeneration zone meets the regeneration requirements. The net flue gas temperature prediction model is as follows:

[0045] (I).

[0046] In equation (I), T j Temperature of the purified flue gas after catalytic oxidation treatment, in °C. ρ is the flue gas density, in kg / m³. 3 c is the specific heat capacity of the flue gas, kJ / (kg·K). C0 is the concentration of CO in the flue gas, g / m³. 3 C v0 The concentration of VOCs in flue gas, in g / m³ 3 y1 represents the first conversion rate, %. y2 represents the second conversion rate, %. λ2 represents the calorific value of VOCs, kJ / mol. M co M is the molar mass of CO, in g / mol. voc The value represents the molar mass of VOCs, in g / mol. The temperature of the purified flue gas after catalytic oxidation treatment is calculated in real time according to formula (I).

[0047] Furthermore, the rotary catalytic bed is divided into n consecutive catalytic units based on the size of the regeneration area. When any one of these catalytic units is regenerated sequentially in the regeneration zone, the remaining (n-1) catalytic units undergo catalytic oxidation treatment in the reaction zone. In other words, the overall catalytic activity of the catalyst within the reaction zone varies, therefore the conversion rates of CO (i.e., the first conversion rate) and VOCs (i.e., the second conversion rate) also vary. Thus, when each catalytic unit is regenerated sequentially, the corresponding first and second catalytic rates within the reaction zone are as follows:

[0048] (II).

[0049] (III).

[0050] In equations (II)-(III), y1(i) represents the first conversion rate during the regeneration of the i-th catalytic unit, %. y2(i) represents the second conversion rate during the regeneration of the i-th catalytic unit, %. S f The catalyst area in the reaction zone is m. 3 S z The catalyst area in the regeneration zone is m. 3 K1 is the first conversion coefficient, with a value of 0.5~0.7. K2 is the second conversion coefficient, with a value of 0.75~0.85. K3 is the third conversion coefficient, with a value of 0.45~0.55. K4 is the fourth conversion coefficient, with a value of 0.60~0.70. i is an integer from 1 to n. The first conversion rate and the second conversion rate during the regeneration of any catalytic unit are calculated according to equations (II) and (III), respectively.

[0051] It should be noted that all formulas in this utility model were obtained by the inventor based on experimental and engineering applications, and all calculations are based on values ​​converted according to specified units. The converted values ​​are then substituted into the formulas for calculation (after unit conversion, only the values ​​are substituted into the formulas for calculation, not the units; the units are only used to adjust the value. In particular, "%" is not used as a unit, but is used to adjust the value; for example, when y2 = 50%, the value of y2 substituted into the formula should be 0.5).

[0052] In this invention, when regenerating a deactivated catalyst, insufficient regeneration temperature hinders effective catalyst regeneration, while excessively high regeneration temperatures can lead to permanent catalyst deactivation. Therefore, the regeneration temperature needs to be controlled within a reasonable range (e.g., 300~450℃, preferably 350~440℃). Specifically, when the calculated temperature of the clean flue gas is lower than the minimum regeneration temperature requirement, it needs to be heated by a heater; conversely, when the calculated temperature is higher than the maximum regeneration temperature requirement, it needs to be cooled (e.g., using an indirect heat exchanger with a low-temperature medium). It should be noted that by predicting the temperature in advance, excessively hot clean flue gas can be cooled or discharged into the chimney instead of entering the regeneration zone, preventing catalyst deactivation due to the agglomeration of precious metal nanoparticles at excessively high temperatures. Alternatively, the heater power can be adjusted in advance for excessively low-temperature clean flue gas to improve catalyst regeneration efficiency. However, if thermocouples are used to measure the clean flue gas temperature directly, it is difficult to adjust the clean flue gas temperature in a timely manner. In particular, when the actual temperature measurement shows that the clean flue gas temperature is too high, the catalyst is already in an excessively high temperature environment, and the nanoparticles have begun to agglomerate.

[0053] In this invention, the diameters of the flue gas conveying pipe and the clean flue gas emission pipe are independently 0.1~30m, preferably 0.2~20m, and more preferably 0.3~10m. The thickness of the shell of the CO and VOCs catalytic reactor is 1~1000mm, preferably 3~800mm, and more preferably 5~500mm. The area ratio of the reaction zone to the regeneration zone is 1~100:1, preferably 2~50:1, and more preferably 3~30:1. The diameter of the rotary catalytic bed is 0.3~30m, more preferably 0.5~20m, and more preferably 1~10m.

[0054] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0055] 1: This utility model, by designing a catalytic bed with a rotary structure and a CO and VOCs catalytic reactor with independently partitioned gas inlet and outlet chambers, can simultaneously perform catalytic oxidation and thermal regeneration of the catalyst, that is, realize online in-situ regeneration of the catalyst, which significantly improves the purification efficiency of flue gas.

[0056] 2: This utility model also realizes the internal circulation of heat in the system by cross-circulating the heat of flue gas in each pipe section, which reduces the need for additional external heat supplementation, reduces heat discharge pollution, and greatly reduces energy consumption, thus greatly reducing the system operating cost.

[0057] 3: This utility model also incorporates a pre-positioned zeolite rotor device before the CO and VOCs catalytic reactors. This zeolite rotor device enriches the VOCs in the original flue gas, reduces the amount of flue gas to be treated, and significantly reduces the amount of CO to be treated in the CO and VOCs catalytic reactors, which is beneficial for the simultaneous and efficient removal of VOCs and CO.

[0058] 4. This utility model can monitor the state of the flue gas to be treated in real time and accurately calculate the real-time temperature of the clean flue gas after catalytic oxidation treatment based on the real-time state of the flue gas to be treated. This provides strong support for the precise, reasonable and timely control of the regeneration temperature in the regeneration zone, effectively promotes the stable circulation of the catalyst and ensures the efficiency of flue gas treatment. Attached Figure Description

[0059] Figure 1 This is a simplified structural diagram of the system described in this utility model.

[0060] Figure 2 This is a simplified structural diagram of the shell of the CO and VOCs catalytic reactor described in this utility model.

[0061] Figure 3 This is a simplified structural diagram of the rotary catalytic bed of this utility model.

[0062] Figure 4 This is a simplified diagram of the overall structure of the system described in this utility model when it is a zeolite rotor.

[0063] Reference numerals: 1: Flue gas conveying pipe; 2: CO and VOCs catalytic reactor; 201: Shell; 2011: Reaction zone; 2012: Regeneration zone; 202: Rotary catalytic bed; 203: Rotary drive mechanism; 2031: Rotary drive motor; 2032: Shaft; 2033: Bearing; 204: Regeneration gas exhaust pipe; 3: Clean flue gas exhaust pipe; 301: Clean flue gas branch pipe; 4: First heater; 5: Second heater; 6: First indirect heat exchanger; 7: Zeolite rotor; 701: Raw flue gas conveying main pipe; 702: Raw flue gas conveying branch pipe; 703: Return gas pipe; 704: High carbon gas conveying pipe; 8: Decarbonization reactor; 801: Decarbonized flue gas exhaust pipe; 9: Second indirect heat exchanger. Detailed Implementation

[0064] The technical solution of this utility model is illustrated below. The scope of protection of this utility model includes, but is not limited to, the following embodiments.

[0065] An in-situ regeneration CO catalytic oxidation system includes a flue gas delivery pipe 1, a CO and VOCs catalytic reactor 2, and a clean flue gas emission pipe 3 connected in series. The CO and VOCs catalytic reactor 2 includes a shell 201 and a rotary catalytic bed 202. The rotary catalytic bed 202 is installed in the inner cavity of the shell 201 via a rotation drive mechanism 203. The inner cavity of the shell 201 is divided into a reaction zone 2011 and a regeneration zone 2012, each with its own independent inlet and outlet. The flue gas delivery pipe 1 is connected to the inlet of the reaction zone 2011, which is connected to the clean flue gas emission pipe 3. A clean flue gas branch pipe 301 extends from the clean flue gas emission pipe 3 and connects to the inlet of the regeneration zone 2012. The outlet of the regeneration zone 2012 is connected to a regeneration gas exhaust pipe 204. The rotary drive mechanism 203 drives the rotary catalytic bed 202 to rotate, so that each catalytic unit in the rotary catalytic bed 202 cycles and alternates between the reaction zone 2011 and the regeneration zone 2012, thereby realizing the in-situ cyclic regeneration of each catalytic unit.

[0066] Preferably, the rotary drive mechanism 203 includes a rotary drive motor 2031 and a rotating shaft 2032. The rotating shaft 2032 passes sequentially through the center of the housing 201 and the rotary catalyst bed 202. The rotating shaft 2032 is movably connected to the housing 201 via a bearing 2033, and the rotating shaft 2032 is fixedly connected to the rotary catalyst bed 202. The rotary drive motor 2031 is located in the housing 201 and connected to one end of the rotating shaft 2032.

[0067] Preferably, the CO catalytic oxidation system further includes a first heater 4, which is disposed on the flue gas conveying pipe 1 or at the gas inlet of the reaction zone 2011.

[0068] Preferably, the CO catalytic oxidation system further includes a second heater 5, which is disposed on the clean flue gas branch pipe 301 or at the air inlet of the regeneration zone 2012.

[0069] Preferably, the CO catalytic oxidation system further includes a first indirect heat exchanger 6, the cold medium channel of which is connected to the flue gas conveying pipe 1. The hot medium channel of the first indirect heat exchanger 6 is connected to the clean flue gas emission pipe 3.

[0070] Preferably, the connection between the first indirect heat exchanger 6 and the flue gas conveying pipe 1 is located upstream of the first heater 4. The connection between the first indirect heat exchanger 6 and the clean flue gas discharge pipe 3 is located downstream of the clean flue gas branch pipe 301.

[0071] Preferably, the CO catalytic oxidation system also includes a zeolite rotor 7. The main flue gas delivery pipe 701 is connected to the inlet of the adsorption zone of the zeolite rotor 7. The exhaust port of the adsorption zone of the zeolite rotor 7 is connected to a high-carbon gas delivery pipe 704. The branch pipe 702 of the raw flue gas delivery pipe is connected to the inlet of the cooling zone of the zeolite rotor 7. The exhaust port of the cooling zone of the zeolite rotor 7 is connected to the inlet of the desorption zone of the zeolite rotor 7 via a return gas pipe 703. The exhaust port of the desorption zone of the zeolite rotor 7 is connected to the flue gas delivery pipe 1.

[0072] Preferably, the CO catalytic oxidation system further includes a decarbonization reactor 8, the inlet of which is connected to a high-carbon gas conveying pipe 704. The exhaust port of the decarbonization reactor 8 is connected to a decarbonization flue gas exhaust pipe 801.

[0073] Preferably, the CO catalytic oxidation system further includes a second indirect heat exchanger 9, the cold medium channel of which is connected to the return gas pipeline 703. The hot medium channel of the second indirect heat exchanger 9 is connected to the decarbonized flue gas exhaust pipeline 801.

[0074] Preferably, flue gas composition detectors are independently installed at both the air inlet and exhaust outlet of the reaction zone 2011.

[0075] As a preferred option, a temperature sensor is also installed at the air inlet of the reaction zone 2011.

[0076] Example 1

[0077] like Figure 1-4As shown, an in-situ regeneration CO catalytic oxidation system includes a flue gas delivery pipe 1, a CO and VOCs catalytic reactor 2, and a clean flue gas emission pipe 3 connected in series. The CO and VOCs catalytic reactor 2 includes a shell 201 and a rotary catalytic bed 202. The rotary catalytic bed 202 is installed in the inner cavity of the shell 201 via a rotation drive mechanism 203. The inner cavity of the shell 201 is divided into a reaction zone 2011 and a regeneration zone 2012, each with its own independent inlet and outlet. The flue gas delivery pipe 1 is connected to the inlet of the reaction zone 2011, which is connected to the clean flue gas emission pipe 3. A clean flue gas branch pipe 301 extends from the clean flue gas emission pipe 3 and connects to the inlet of the regeneration zone 2012. The outlet of the regeneration zone 2012 is connected to a regeneration gas exhaust pipe 204. The rotary drive mechanism 203 drives the rotary catalytic bed 202 to rotate, so that each catalytic unit in the rotary catalytic bed 202 cycles and alternates between the reaction zone 2011 and the regeneration zone 2012, thereby realizing the in-situ cyclic regeneration of each catalytic unit.

[0078] Example 2

[0079] The embodiment 1 is repeated, except that the rotary drive mechanism 203 includes a rotary drive motor 2031 and a rotating shaft 2032. The rotating shaft 2032 passes through the center of the housing 201 and the rotary catalyst bed 202 in sequence. The rotating shaft 2032 is movably connected to the housing 201 via a bearing 2033, and the rotating shaft 2032 is fixedly connected to the rotary catalyst bed 202. The rotary drive motor 2031 is located in the housing 201 and is connected to one end of the rotating shaft 2032.

[0080] Example 3

[0081] Example 2 is repeated, except that the CO catalytic oxidation system further includes a first heater 4, which is disposed on the flue gas conveying pipe 1.

[0082] Example 4

[0083] Example 3 is repeated, except that the CO catalytic oxidation system further includes a second heater 5, which is disposed on the clean flue gas branch pipe 301.

[0084] Example 5

[0085] The embodiment 4 is repeated, except that the CO catalytic oxidation system further includes a first indirect heat exchanger 6, the cold medium channel of which is connected to the flue gas conveying pipe 1. The hot medium channel of the first indirect heat exchanger 6 is connected to the clean flue gas emission pipe 3.

[0086] Example 6

[0087] Example 5 is repeated, except that the connection between the first indirect heat exchanger 6 and the flue gas conveying pipe 1 is located upstream of the first heater 4. The connection between the first indirect heat exchanger 6 and the clean flue gas discharge pipe 3 is located downstream of the clean flue gas branch pipe 301.

[0088] Example 7

[0089] The CO catalytic oxidation system is repeated in Example 6, except that it also includes a zeolite rotor 7. The main flue gas delivery pipe 701 is connected to the inlet of the adsorption zone of the zeolite rotor 7. The exhaust port of the adsorption zone of the zeolite rotor 7 is connected to a high-carbon gas delivery pipe 704. The branch pipe 702 is connected to the inlet of the cooling zone of the zeolite rotor 7. The exhaust port of the cooling zone of the zeolite rotor 7 is connected to the inlet of the desorption zone of the zeolite rotor 7 via a return gas pipe 703. The exhaust port of the desorption zone of the zeolite rotor 7 is connected to the flue gas delivery pipe 1.

[0090] Example 8

[0091] The embodiment 7 is repeated, except that the CO catalytic oxidation system further includes a decarbonization reactor 8, the inlet of which is connected to a high-carbon gas conveying pipe 704. The exhaust port of the decarbonization reactor 8 is connected to a decarbonization flue gas exhaust pipe 801.

[0092] Example 9

[0093] The embodiment 8 is repeated, except that the CO catalytic oxidation system further includes a second indirect heat exchanger 9, the cold medium channel of which is connected to the return gas pipeline 703. The hot medium channel of the second indirect heat exchanger 9 is connected to the decarbonized flue gas exhaust pipeline 801.

[0094] Example 10

[0095] Example 9 was repeated, except that flue gas composition detectors were independently installed at both the air inlet and exhaust outlet of the reaction zone 2011.

[0096] Example 11

[0097] Repeat Example 10, except that a temperature sensor is also installed at the air inlet of the reaction zone 2011.

[0098] Example 12

[0099] A method for catalytic oxidation of CO using the CO catalytic oxidation system described in Example 11, the method comprising the following steps:

[0100] 1) Flue gas containing CO and VOCs is fed into the reaction zone 2011 of the CO and VOCs catalytic reactor 2 for catalytic oxidation treatment using the active catalyst in the rotary catalytic bed 202 to obtain clean flue gas. The deactivated catalyst in the rotary catalytic bed 202 is then rotated to the regeneration zone 2012.

[0101] 2) A portion of the clean flue gas is sent to the regeneration zone 2012 to regenerate the deactivated catalyst, obtaining a regenerated catalyst. The regenerated catalyst is then rotated into the reaction zone 2011 to participate in catalytic oxidation. Steps 1) and 2) are repeated in a cycle.

[0102] 3) Monitor the CO and VOC content in the flue gas containing CO and VOCs at the inlet of reaction zone 2011 in real time, and adjust the temperature of the clean flue gas fed into regeneration zone 2012 in real time according to the changes in CO and VOC content, so that the catalytic activity of the regenerated catalyst meets the operating conditions.

[0103] Example 13

[0104] A method for catalytic oxidation of CO using the CO catalytic oxidation system described in Example 11, the method comprising the following steps:

[0105] 1) Flue gas containing CO and VOCs is fed into the reaction zone 2011 of the CO and VOCs catalytic reactor 2 for catalytic oxidation treatment using the active catalyst in the rotary catalytic bed 202 to obtain clean flue gas. The deactivated catalyst in the rotary catalytic bed 202 is then rotated to the regeneration zone 2012.

[0106] 2) A portion of the clean flue gas is sent to the regeneration zone 2012 to regenerate the deactivated catalyst, obtaining a regenerated catalyst. The regenerated catalyst is then rotated into the reaction zone 2011 to participate in catalytic oxidation. Steps 1) and 2) are repeated in a cycle.

[0107] 3) Monitor the CO and VOC content in the flue gas containing CO and VOCs at the inlet of reaction zone 2011 in real time, and adjust the temperature of the clean flue gas fed into regeneration zone 2012 in real time according to the changes in CO and VOC content, so that the catalytic activity of the regenerated catalyst meets the operating conditions.

[0108] 4) A portion of the original flue gas is adsorbed in the adsorption zone of the zeolite rotor to obtain high-carbon flue gas, and the high-carbon flue gas is decarbonized to obtain decarbonized flue gas; the remaining portion of the original flue gas is passed through the cooling zone of the zeolite rotor and then exchanged with the decarbonized flue gas before passing through the desorption zone of the zeolite rotor to obtain the flue gas to be treated.

[0109] Example 14

[0110] Repeat Example 13, except that in step 4), the portion of the original flue gas passing through the zeolite rotor adsorption zone accounts for 90-95% of the total volume of the original flue gas.

[0111] Example 15

[0112] Repeat Example 14, except that the temperature of the portion of purified flue gas fed into the regeneration zone 2012 is adjusted in real time according to changes in CO and VOC content. Specifically, the temperature of the purified flue gas after catalytic oxidation is first calculated based on changes in CO and VOC content. Then, based on the calculated temperature, the temperature of this portion of purified flue gas fed into the regeneration zone 2012 is selectively increased or decreased to ensure that its temperature matches the target regeneration temperature. The temperature of the purified flue gas after catalytic oxidation is calculated using the following formula:

[0113] (I).

[0114] In equation (I), T j Temperature of the purified flue gas after catalytic oxidation treatment, in °C. ρ is the flue gas density, in kg / m³. 3 c is the specific heat capacity of the flue gas, kJ / (kg·K). C0 is the concentration of CO in the flue gas, g / m³. 3 C v0 The concentration of VOCs in flue gas, in g / m³ 3 y1 represents the first conversion rate, %. y2 represents the second conversion rate, %. λ2 represents the calorific value of VOCs, kJ / mol. M co M is the molar mass of CO, in g / mol. voc The value represents the molar mass of VOCs, in g / mol. The temperature of the purified flue gas after catalytic oxidation treatment is calculated in real time according to formula (I).

[0115] Example 16

[0116] Repeat Example 15, except that the rotary catalytic bed 202 is divided into n consecutive catalytic units according to the size of the regeneration area of ​​the regeneration zone 2012. When the regeneration zone 2012 regenerates any one of the catalytic units in sequence, the remaining (n-1) catalytic units undergo catalytic oxidation treatment in the reaction zone 2011. Then:

[0117] (II).

[0118] (III).

[0119] In equations (II)-(III), y1(i) represents the first conversion rate during the regeneration of the i-th catalytic unit, %. y2(i) represents the second conversion rate during the regeneration of the i-th catalytic unit, %. S fLet m be the catalyst area of ​​the reaction zone (2011). 3 S z Let m be the catalyst area in the regeneration zone (2012). 3 K1 is the first conversion coefficient, with a value of 0.5~0.7. K2 is the second conversion coefficient, with a value of 0.75~0.85. K3 is the third conversion coefficient, with a value of 0.45~0.55. K4 is the fourth conversion coefficient, with a value of 0.60~0.70. i is an integer from 1 to n. The first conversion rate and the second conversion rate during the regeneration of any catalytic unit are calculated according to equations (II) and (III), respectively.

[0120] Example 17

[0121] Repeat Example 16, except that the target regeneration temperature lower limit and upper limit of the regeneration zone 2012 are set to T respectively. z1 and T z2 , ℃. Then we have:

[0122] When T j <T z1 At that time, the portion of clean flue gas sent into the regeneration zone 2012 is heated to [T]. j ,T z1 ].

[0123] When T z1 ≤T j ≤T z2 At this time, there is no need to heat or cool down this portion of the clean flue gas sent into the regeneration zone 2012.

[0124] When T z2 <T j At that time, the portion of clean flue gas sent into the regeneration zone 2012 will be cooled to [T]. j ,T z1 ].

[0125] Example 18

[0126] Repeat Example 17, except that the heating is performed using a heater and the cooling is performed using an indirect heat exchanger.

[0127] Application Example 1

[0128] The method described in Example 18 was used to treat the flue gas from the steel plant:

[0129] The initial temperature of the raw flue gas was approximately 150℃, and the CO concentration was approximately 10 g / m³. 3 The concentration of benzene-based VOCs is approximately 0.05 g / m³. 3 The total amount is approximately 1 million m³ 3First, 90% of the original flue gas by volume is fed into the adsorption zone of a zeolite rotor for adsorption treatment to obtain high-carbon flue gas (temperature approximately 150℃, CO concentration approximately 10 g / m³). 3 The concentration of benzene-based VOCs is approximately 0.002 g / m³. 3 Then, the high-carbon flue gas is fed into a low-temperature CO reactor for decarbonization treatment to obtain decarbonized flue gas (temperature approximately 210℃, CO concentration approximately 2 g / m³). 3 The concentration of benzene-based VOCs is approximately 0.002 g / m³. 3 The raw flue gas, accounting for 10% of the volume, is passed through the adsorption zone of a zeolite rotor and then indirectly heat-exchanged with the decarbonized flue gas to obtain the desorption carrier gas (temperature approximately 190℃, CO concentration approximately 10 g / m³). 3 The concentration of benzene-based VOCs is approximately 0.05 g / m³. 3 Then, the desorption carrier gas is fed into the desorption zone of the zeolite rotor for adsorption treatment to obtain the flue gas to be treated (temperature approximately 190℃, CO concentration approximately 10 g / m³). 3 The concentration of benzene-based VOCs is approximately 1.5 g / m³. 3 ).

[0130] The flue gas to be treated is heated to 280°C using a heater and then fed into the reaction zone of a CO and VOCs catalytic reactor for catalytic oxidation to obtain clean flue gas (temperature approximately 420°C, CO concentration approximately 2.0 g / m³). 3 The concentration of benzene-based VOCs is approximately 0.51 g / m³. 3 ).

[0131] After three months of system operation, the overall CO conversion rate of the catalyst in the reaction zone was detected to have decreased to approximately 60%, and the VOCs conversion rate to approximately 50%. Under the current operating conditions, the CO concentration (C0) is approximately 10 g / m³. 3 The concentration C of benzene series VOCs v0 Approximately 1.5 g / m 3 The temperature of the flue gas to be treated is approximately 280℃, and the density ρ of the flue gas to be treated is approximately 0.64 kg / m³. 3 The specific heat capacity c of the flue gas to be treated is approximately 1.1 kJ / (kg·K), M CO The concentration is 44 g / mol, the calorific value of CO λ1 is approximately 283.5 kJ / mol, and M VOC Given a concentration of 78 g / mol and a VOCs calorific value of λ2 of approximately 3280 kJ / mol, and taking y1(0) = 0.6 and y2(0) = 0.5, we have:

[0132] T j =T0+ ≈280+100=380℃.

[0133] The temperature of the purified flue gas, calculated using formula (I), is approximately 380℃. The proposed temperature for the regeneration zone is 450℃. Therefore, under the current operating conditions, a heater is needed to further heat this portion of the purified flue gas, which serves as the regeneration heat source, by 70℃. The CO concentration in the purified flue gas under the current operating conditions is detected to be approximately 4 g / m³. 3 The concentration of VOCs is approximately 0.75 g / m³. 3 .

[0134] Since the CO and VOC conversion rates are both low, making it difficult to continue meeting purification requirements, a rotary drive mechanism is activated to rotate the rotary catalytic bed. This rotates the fresh catalytic unit located in the regeneration zone to the reaction zone, while simultaneously rotating the catalytic unit closest to the regeneration zone in the reaction zone (denoted as the 1st catalytic unit, and sequentially as the 2nd, 3rd, ..., i-th, ... n-th catalytic units in the opposite direction of rotation) to the regeneration zone. The regeneration zone temperature is set at 450℃. Under the current operating conditions: the first conversion coefficient K1 is 0.6, the second conversion coefficient K2 is 0.8, the third conversion coefficient K3 is 0.5, and the fourth conversion coefficient K4 is 0.66. The ratio of the catalytic area of ​​the regeneration zone to the reaction zone is S. z :S f =1:4; therefore, the first conversion rate and the second conversion rate during the regeneration of the first catalytic unit are respectively:

[0135] =0.65 (i.e., 65%).

[0136] =0.54 (i.e., 54%).

[0137] The net flue gas temperature during the regeneration of the first catalytic unit is:

[0138] T j =T0+ ≈280+108=388℃.

[0139] Under the current operating conditions (during the regeneration of the first catalytic unit), the temperature of the resulting clean flue gas, calculated using formulas (I)-(III), is approximately 388℃. Therefore, a heater is needed to raise the temperature of this portion of the clean flue gas, which serves as the regeneration heat source, by another 62℃. The CO concentration in the clean flue gas under the current operating conditions is detected to be approximately 3.5 g / m³. 3 The concentration of VOCs was approximately 0.69 g / m³. 3 This process is repeated until all flue gas purification is complete.

Claims

1. A CO catalytic oxidation system for in-situ regeneration, characterized by: The CO catalytic oxidation system includes a flue gas conveying pipe (1), a CO and VOCs catalytic reactor (2), and a clean flue gas emission pipe (3) connected in series. The CO and VOCs catalytic reactor (2) includes a shell (201) and a rotary catalytic bed (202). The rotary catalytic bed (202) is installed in the inner cavity of the shell (201) via a rotary drive mechanism (203). The inner cavity of the shell (201) is divided into a reaction zone (2011) and a regeneration zone (2012), and both the reaction zone (2011) and the regeneration zone (2012) are independently equipped with inlets and outlets. The flue gas conveying pipe (1) and the reaction zone (2012) are connected in series. The air inlet of the reaction zone (2011) is connected to the air inlet of the reaction zone (2011), which is connected to the clean flue gas emission pipe (3). A clean flue gas branch pipe (301) is led out from the clean flue gas emission pipe (3) and connected to the air inlet of the regeneration zone (2012). The exhaust port of the regeneration zone (2012) is connected to the regeneration gas exhaust pipe (204). The rotary drive mechanism (203) drives the rotary catalytic bed (202) to rotate, so that each catalytic unit in the rotary catalytic bed (202) circulates and alternates between the reaction zone (2011) and the regeneration zone (2012), thereby realizing the in-situ cyclic regeneration of each catalytic unit.

2. The CO catalytic oxidation system of claim 1, wherein: The rotary drive mechanism (203) includes a rotary drive motor (2031) and a rotating shaft (2032); the rotating shaft (2032) passes through the center of the shell (201) and the rotary catalyst bed (202) in sequence, and the rotating shaft (2032) is movably connected to the shell (201) through a bearing (2033), and the rotating shaft (2032) is fixedly connected to the rotary catalyst bed (202); the rotary drive motor (2031) is located in the shell (201) and is connected to one end of the rotating shaft (2032).

3. The CO catalytic oxidation system of claim 1, wherein: The CO catalytic oxidation system also includes a first heater (4), which is installed on the flue gas conveying pipe (1) or at the gas inlet of the reaction zone (2011).

4. The CO catalytic oxidation system of claim 3, wherein: The CO catalytic oxidation system also includes a second heater (5), which is installed on the clean flue gas branch pipe (301) or at the air inlet of the regeneration zone (2012).

5. The CO catalytic oxidation system of claim 4, wherein: The CO catalytic oxidation system also includes a first indirect heat exchanger (6), the cold medium channel of the first indirect heat exchanger (6) is connected to the flue gas conveying pipeline (1); the hot medium channel of the first indirect heat exchanger (6) is connected to the clean flue gas emission pipeline (3).

6. The CO catalytic oxidation system of claim 5, wherein: The connection between the first indirect heat exchanger (6) and the flue gas conveying pipe (1) is located upstream of the first heater (4); the connection between the first indirect heat exchanger (6) and the clean flue gas discharge pipe (3) is located downstream of the clean flue gas branch pipe (301).

7. The CO catalytic oxidation system of claim 1, wherein: The CO catalytic oxidation system also includes a zeolite rotor (7); the main flue gas conveying pipe (701) is connected to the air inlet of the adsorption zone of the zeolite rotor (7); the exhaust port of the adsorption zone of the zeolite rotor (7) is connected to a high-carbon gas conveying pipe (704); the branch pipe of the original flue gas conveying pipe (702) is connected to the air inlet of the cooling zone of the zeolite rotor (7); the exhaust port of the cooling zone of the zeolite rotor (7) is connected to the air inlet of the desorption zone of the zeolite rotor (7) through the return gas pipe (703); and the exhaust port of the desorption zone of the zeolite rotor (7) is connected to the flue gas conveying pipe (1).

8. The CO catalytic oxidation system of claim 7, wherein: The CO catalytic oxidation system also includes a decarbonization reactor (8), the inlet of which is connected to a high-carbon gas conveying pipeline (704); the outlet of the decarbonization reactor (8) is connected to a decarbonization flue gas discharge pipeline (801).

9. The CO catalytic oxidation system of claim 8, wherein: The CO catalytic oxidation system also includes a second indirect heat exchanger (9), the cold medium channel of the second indirect heat exchanger (9) is connected to the return gas pipeline (703); the hot medium channel of the second indirect heat exchanger (9) is connected to the decarbonized flue gas discharge pipeline (801).

10. The CO catalytic oxidation system of any one of claims 1-9, wherein: Flue gas composition detectors are independently installed at both the inlet and outlet of the reaction zone (2011); and / or A temperature sensor is also installed at the air inlet of the reaction zone (2011).

Images