Catalytic oxidation system and method for safe treatment and heat energy recovery of carbonized tail gas
By combining condensation pretreatment and catalytic oxidation system with activated carbon adsorption bypass, the safety and heat recovery issues of high-concentration carbonized tail gas are solved, achieving safe and efficient tail gas treatment and heat recovery, and ensuring continuous operation and energy efficiency optimization of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-29
- Publication Date
- 2026-04-14
AI Technical Summary
Existing catalytic oxidation devices face problems such as the risk of combustion and explosion, catalyst deactivation, the need for complete shutdown and maintenance, and low heat utilization when treating high-concentration organic waste gas.
The system, which employs a four-tiered structure of condensation pretreatment, catalytic oxidation, waste heat recovery, and emergency adsorption, includes a tube heat exchanger, a buffer tank, a combustible gas detector, a flame arrestor, a catalytic oxidation furnace, a plate gas-to-gas heat exchanger, a variable frequency fan, and an activated carbon adsorption bypass. Through condensation concentration reduction, dilution adjustment, and activated carbon bypass switching, it achieves safe and efficient purification and heat recovery.
It achieves safe treatment of carbonization exhaust gas, reduces the risk of combustion and explosion, improves the safety and energy efficiency of the system, ensures continuous operation of the equipment, and optimizes the utilization rate of heat.
Smart Images
Figure CN121854872A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial waste gas treatment technology, specifically to a catalytic oxidation system and method for the safe treatment and heat recovery of carbonization tail gas. Background Technology
[0002] In the field of catalytic combustion, the focus is mainly on optimizing heat management and enhancing pollutant treatment capabilities. The industry is intensifying technological research to address core issues such as "runaway temperatures" (localized overheating), energy waste, and secondary pollution. Existing catalytic oxidation devices have several drawbacks when treating high-concentration organic waste gases: 1. Directly feeding waste gas into the catalytic oxidation furnace poses a risk of combustion and explosion (e.g., methane concentration > 25% LEL); 2. Untreated waste gas leads to carbon deposition and deactivation on the catalyst surface; 3. Equipment maintenance requires a complete shutdown, affecting production continuity. For example, using single-stage catalytic oxidation does not address safety and system redundancy issues; 4. The heat released by catalytic combustion has a low utilization rate. Summary of the Invention
[0003] The purpose of this invention is to provide a catalytic oxidation system and method for the safe treatment and heat recovery of carbonization tail gas. Through a four-fold structure of condensation pretreatment, catalytic oxidation, waste heat recovery, and emergency adsorption, it achieves safe and efficient purification and is applicable to tail gas containing combustible VOCs generated by carbonization furnaces, coking plants, etc.
[0004] The technical solution of the present invention is as follows: a catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas, comprising a main pipeline, wherein a tube heat exchanger, a buffer tank, a combustible gas detector, a flame arrester, a catalytic oxidation furnace, and a PID non-methane total hydrocarbon analyzer are connected in sequence on the main pipeline.
[0005] It also includes a plate gas-to-gas heat exchanger and a variable frequency fan. The plate gas-to-gas heat exchanger and the variable frequency fan are installed on the main pipeline and located between the catalytic oxidation furnace and the PID non-methane total hydrocarbon analyzer. The plate gas-to-gas heat exchanger is connected to the fresh air valve through the pipeline.
[0006] It also includes a storage tank, which is connected to the shell and tube heat exchanger to receive the condensate discharged from the shell and tube heat exchanger; and the storage tank is also connected to the plate air-to-air heat exchanger through a fresh air valve.
[0007] A three-way valve is installed on the main pipeline between the combustible gas detector and the flame arrester, and the three-way valve is connected to the activated carbon adsorption bypass.
[0008] The three-way valve includes a valve stem seal ring, valve body, valve core, and three-way valve actuator. Under normal circumstances, the valve body is connected to the left and right sides. When the carbonization tail gas concentration is >50%LEL, the valve core rises and blocks the valve body to the left and right sides, allowing the gas to flow to the activated carbon adsorption bypass.
[0009] The catalytic oxidation furnace includes finned heating tubes and spray cooling nozzles. The finned heating tubes are used to control the temperature and are located in the reaction zone, which is filled with catalyst. The spray cooling nozzles are used for rapid cooling.
[0010] The storage tank is equipped with a rotating scraper at the bottom, with a rotation speed of 2-5 r / min. The storage tank is also equipped with a liquid level sensor and an automatic drain valve.
[0011] A catalytic oxidation method for the safe treatment and heat recovery of carbonization tail gas includes the following steps: S1: The carbonization tail gas enters the tube heat exchanger for cooling; S2: The carbonized tail gas passes through a buffer tank and its concentration is confirmed by a detector before it enters the catalytic oxidation furnace through a flame arrester, where it is oxidized at high temperature. S3: The variable frequency fan generates negative pressure, and outside air enters through the fresh air valve. The fresh air is preheated by the plate air-to-air heat exchanger and then sent to the catalytic oxidation furnace to mix with the carbonization tail gas. S4: The PID non-methane total hydrocarbon analyzer analyzes the exhaust gas after high-temperature oxidation in the catalytic oxidation furnace, and discharges the exhaust gas after it meets the standards.
[0012] In S1, the tube heat exchanger cools the carbonization tail gas to 10-15°C and separates the condensate into a storage tank; In S2-S4, when the methane concentration detected by the combustible gas detector is >20%LEL, the variable frequency fan increases the fresh air volume; when the methane concentration detected after mixing is >50%LEL, the catalytic oxidation furnace is shut down and the three-way valve is switched to the activated carbon adsorption bypass.
[0013] The beneficial effects of this invention are: (1) Enhanced inherent safety: Through triple protection of condensation reduction, combustible gas detection and flame arrester, the risk of explosion accidents is reduced to zero; (2) Energy efficiency optimization: latent heat recovery of shell and tube heat exchangers + sensible heat recovery of plate heat exchangers, with a comprehensive energy saving rate of >40%; (3) Continuous operation guarantee: The bypass activated carbon adsorber achieves zero downtime for maintenance; (4) Intelligent monitoring: The PID analyzer 10 is linked with the PLC, and the bypass system is automatically started when the standard is exceeded. Attached Figure Description
[0014] Figure 1a This is a schematic diagram of the overall system. Figure 1b This is a schematic diagram of the overall system. Figure 2 For the safety interlock control logic block diagram (combustible gas concentration → fresh air volume / valve action); Figure 3This is a cross-sectional view of the activated carbon bypass switching valve (three-way valve core sealing structure). Figure 4 This is a schematic diagram of the catalytic oxidation furnace structure; Figure 5 Flowchart of a catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas In the diagram: 1. Shell and tube heat exchanger, 2. Storage tank, 3. Variable frequency fan, 4. Combustible gas detector, 5. Buffer tank, 6. Flame arrester, 7. Catalytic oxidation furnace, 8. Plate gas-to-gas heat exchanger, 9. Three-way valve, 10. PID non-methane total hydrocarbon analyzer, 11. Valve stem seal ring, 12. Valve body, 13. Valve core, 14. Three-way valve actuator, 301. Fresh air valve, 701. Finned electric heating tube, 702. Reaction zone, 703. Spray cooling nozzle. Detailed Implementation
[0015] Many specific details are set forth in the following description to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application; therefore, this application is not limited to the specific embodiments disclosed below.
[0016] The terminology used in one or more embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this application. The singular forms “a,” “the,” and “the” used in one or more embodiments of this application and in the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” used in one or more embodiments of this application refers to and includes any or all possible combinations of one or more associated listed items.
[0017] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this application, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this application, and similarly, second may also be referred to as first.
[0018] like Figure 1a As shown in Figures 1 and 2, a catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas includes the following components connected in sequence on the main pipeline: a tube heat exchanger 1, a buffer tank 5, a combustible gas detector 4, a flame arrester 6, a catalytic oxidation furnace 7, a plate gas-to-gas heat exchanger 8, a variable frequency fan 3, and a PID non-methane total hydrocarbon analyzer 10. Specifically, the shell and tube heat exchanger 1 is used to cool the carbonized tail gas to 10-15℃ and separate the condensate; 5℃ chilled water is passed through the outside of the tubes of the shell and tube heat exchanger 1 to cool the carbonized tail gas to 10-15℃. Specifically, it also includes a storage tank 2, which is connected to the shell-and-tube heat exchanger 1 to receive the condensate discharged from the shell-and-tube heat exchanger 1; the storage tank 2 is also connected to the plate air-to-air heat exchanger 8 through a fresh air valve 301; the bottom of the storage tank 2 is equipped with a rotating scraper mechanism with a scraper speed of 2-5 r / min. The storage tank 2 is equipped with a liquid level sensor and an automatic drain valve.
[0019] Specifically, the combustible gas detector 4 is installed on the outlet pipe of the buffer tank 5, and the buffer tank 5 is connected to the flame arrester 6; a three-way valve 9 is installed in the pipeline between the combustible gas detector 4 and the flame arrester 6, and the three-way valve 9 is connected to the activated carbon adsorption bypass; the three-way valve 9 is a pneumatic actuator and is interlocked with the combustible gas detector 4: when the concentration is >50%LEL, it automatically switches to the activated carbon adsorption bypass.
[0020] The inlet of the catalytic oxidation furnace 7 is connected to a flame arrester 6; The variable frequency fan 3 generates negative pressure by means of the suction force of the variable frequency fan at the tail end, so that the fresh air from the outside enters through the fresh air valve 301 and passes through the plate gas-to-gas heat exchanger 8, using the waste heat of the purified air to preheat the fresh air. The gas in the storage tank 2 also enters the plate gas-to-gas heat exchanger 8 and is sent to the catalytic oxidation furnace 7 to increase the oxygen content of the catalytic oxidation furnace 7 and enhance the oxidation effect of the catalytic oxidation furnace 7. The PID non-methane total hydrocarbon analyzer 10 is installed at the outlet of the variable frequency fan 3.
[0021] like Figure 3 As shown, the three-way valve 9 includes a valve stem sealing ring 11, a valve body 12, a valve core 13, and a three-way valve actuator 14. The left and right sides of the three-way valve 9 are respectively connected to the combustible gas detector 4 and the flame arrester 6. Under normal circumstances, the left and right sides of the valve body 12 are connected, and the carbonized tail gas is horizontal (left and right) to the three-way valve 9. When the concentration is >50%LEL, the valve core 13 rises, blocking the left and right sides of the valve body 12, so that the gas flows to the activated carbon adsorption bypass. like Figure 4 As shown, the catalytic oxidation furnace 7 includes a finned heating tube 701, which is used to control the temperature and is located in the reaction zone 702, which is filled with a Pd-Pt-Rh catalyst with a pore density of 400 cpsi; and a spray cooling nozzle 703 for rapid cooling. The plate-type gas-to-gas heat exchanger 8 uses stainless steel corrugated plates, and the heat exchange area to exhaust gas flow rate ratio is 1.2m². 2 / (m 3 The plate-type air-to-air heat exchanger 8 exchanges heat between the 650℃ purified air and the fresh air, preheating the fresh air to 250℃. The specific steps involved in the work are as follows: S1: The carbonization tail gas enters the tube heat exchanger 1, where it is cooled to 10-15°C and the condensate is separated into the storage tank 2. S2: The carbonization tail gas passes through the buffer tank 5 and is confirmed by the detector 4 to have a concentration of <10%LEL. Then it enters the catalytic oxidation furnace 7 through the flame arrester 6 and is oxidized at high temperature in the catalytic oxidation furnace 7. Specifically, the high-temperature oxidation temperature is 300-700℃, preferably 300-500℃.
[0022] S3: The variable frequency fan 3 generates negative pressure, and outside air (fresh air) enters through the fresh air valve 301. After being preheated by the plate air-to-air heat exchanger 8, it is sent to the catalytic oxidation 7 to mix with the carbonization tail gas and enhance the oxidation effect. S4: The PID non-methane total hydrocarbon analyzer 10 analyzes the exhaust gas after high-temperature oxidation in the catalytic oxidation furnace 7, and discharges the exhaust gas after it meets the standard. Specifically, the emission limits for exhaust gases shall be implemented in accordance with the emission concentration limits for volatile organic compounds in the "Integrated Emission Standard for Air Pollutants" GB16297; the emission limits for odor concentrations shall be implemented in accordance with the emission standard values for odor pollutants in the "Emission Standard for Odor Pollutants" GB14554-93.
[0023] When the methane concentration after the exhaust gas from the combustible gas detector 4 is mixed with fresh air is >20% LEL, the variable frequency fan 3 automatically increases the fresh air volume; when the methane concentration after mixing is >50% LEL, the catalytic oxidation furnace 7 is shut down and the three-way valve 9 is switched to the activated carbon adsorption bypass.
[0024] This invention reduces the concentration of exhaust gas to a safe range through condensation and concentration reduction using a tube-and-shell heat exchanger and dilution with fresh air. A triple protection system is installed before the catalytic oxidizer 7, consisting of a combustible gas detector 4, a buffer tank 5, and a flame arrester 6. An activated carbon adsorption bypass is configured, and online switching is achieved through an activated carbon bypass switching valve. The exhaust gas decomposes into CO2 / H2O within the catalytic oxidizer 7, and the high-temperature purified gas recovers heat energy via a plate heat exchanger (8). The system combines inherent safety, energy optimization, and uninterrupted operation advantages, making it particularly suitable for high-concentration carbonized exhaust gas containing tar and combustible components (phenol and its compounds, methane, and non-methane total hydrocarbons). It should be noted that in this document, the terms "comprising," "including," or any other term thereof are used interchangeably. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
[0025] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.
[0026] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.
[0027] The preferred embodiments disclosed above are merely illustrative of this application. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this application. These embodiments are selected and specifically described in this application to better explain the principles and practical applications of this application, thereby enabling those skilled in the art to better understand and utilize this application.
Claims
1. A catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas, characterized in that: It includes a main pipeline, which is connected in sequence to a tube heat exchanger (1), a buffer tank (5), a combustible gas detector (4), a flame arrester (6), a catalytic oxidation furnace (7), and a PID non-methane total hydrocarbon analyzer (10).
2. The catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas according to claim 1, characterized in that: It also includes a plate gas-to-gas heat exchanger (8) and a variable frequency fan (3). The plate gas-to-gas heat exchanger (8) and the variable frequency fan (3) are installed on the main pipeline and located between the catalytic oxidation furnace (7) and the PID non-methane total hydrocarbon analyzer (10). The plate gas-to-gas heat exchanger (8) is connected to the fresh air valve (301) through the pipeline.
3. The catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas according to claim 2, characterized in that: It also includes a storage tank (2), which is connected to the tube heat exchanger (1) to receive the condensate discharged from the tube heat exchanger (1); and the storage tank (2) is also connected to the plate air-to-air heat exchanger (8) through a fresh air valve (301).
4. The catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas according to claim 3, characterized in that: A three-way valve (9) is installed on the main pipeline between the combustible gas detector (4) and the flame arrester (6), and the three-way valve (9) is connected to the activated carbon adsorption bypass.
5. The catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas according to claim 4, characterized in that: The three-way valve (9) includes a valve stem sealing ring (11), a valve body (12), a valve core (13), and a three-way valve actuator (14). Under normal circumstances, the valve body (12) is connected to the left and right. When the carbonization tail gas concentration is >50%LEL, the valve core (13) rises and blocks the valve body (12) to the left and right, so that the gas flows to the activated carbon adsorption bypass.
6. The catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas according to claim 4, characterized in that: The catalytic oxidation furnace (7) includes a finned heating tube (701) and a spray cooling nozzle (703). The finned heating tube (701) is used to control the temperature and is located in the reaction zone (702). The reaction zone (702) is filled with catalyst, and the spray cooling nozzle (703) is used for rapid cooling.
7. The catalytic oxidation system for safe treatment and heat recovery of carbonization tail gas according to claim 4, characterized in that: The storage tank (2) is equipped with a rotating scraper at the bottom, with a scraper rotation speed of 2-5 r / min. The storage tank (2) is equipped with a liquid level sensor and an automatic drain valve.
8. A catalytic oxidation method for safe treatment and heat recovery of carbonization tail gas, using the system described in claim 7, characterized in that: Includes the following steps: S1: The carbonized tail gas enters the tube heat exchanger (1) for cooling; S2: The carbonized tail gas passes through the buffer tank (5) and the concentration is confirmed by the detector (4). Then it enters the catalytic oxidation furnace (7) through the flame arrester (6) and is oxidized at high temperature in the catalytic oxidation furnace (7). S3: The variable frequency fan (3) generates negative pressure, and the outside air enters through the fresh air valve (301). The fresh air is preheated by the plate gas heat exchanger (8) and then sent to the catalytic oxidation furnace (7) to mix with the carbonization tail gas. S4: The PID non-methane total hydrocarbon analyzer (10) analyzes the waste gas after high-temperature oxidation in the catalytic oxidation furnace (7), and discharges the waste gas after it meets the standard.
9. The catalytic oxidation method for safe treatment and heat recovery of carbonization tail gas according to claim 8, characterized in that: In S1, the tube heat exchanger (1) cools the carbonization tail gas to 10-15°C and separates the condensate into the storage tank (2).
10. The catalytic oxidation method for safe treatment and heat recovery of carbonization tail gas according to claim 8, characterized in that: In S2-S4, when the combustible gas detector (4) detects a methane concentration >20%LEL, the variable frequency fan (3) increases the fresh air volume; when the methane concentration after mixing is >50%LEL, the catalytic oxidation furnace (7) is shut down, and the three-way valve (9) is switched to the activated carbon adsorption bypass.