Tail gas recycling method and system for porous carbon preparation and porous carbon preparation system

Abstract

The invention relates to the technical field of porous carbon preparation, in particular to a tail gas recycling system which is characterized by being applied to a porous carbon preparation device and comprising an incinerator connected with the porous carbon preparation device and used for incinerating tail gas discharged by the porous carbon preparation device; the air pocket and the heat exchange device are connected with each other, the heat exchange device is connected with the incinerator, saturated steam generated by the air pocket and tail gas of the incinerator complete heat exchange in the heat exchange device to prepare superheated steam, and at least part of the superheated steam is conveyed back to the porous carbon preparation device to be used for preparing porous carbon.

Description

Technical Field

[0001] This patent relates to the field of porous carbon preparation technology, and more specifically, to a system for treating exhaust gas and recovering waste heat during the porous carbon preparation process. Background Technology

[0002] With the rapid development of new energy vehicles, energy storage systems, and other fields, porous carbon, as the framework of silicon-carbon anode materials, has attracted increasing attention in its preparation process. During the preparation of porous carbon, especially when using the resin method for carbonization and activation in a rotary kiln, high-temperature exhaust gases containing volatile organic compounds are generated. These exhaust gases not only require environmental treatment but also carry a large amount of heat energy.

[0003] In the prior art, CN120328550A discloses a porous carbon production method and system, in which the tail gas from the fluidized bed reactor outlet is treated by passing it through a multi-stage scrubbing tower and then used to preheat inert gas. However, in this scheme, the tail gas needs to be treated by the scrubbing tower, resulting in a large amount of heat being carried away by the scrubbing liquid, with only a small portion of heat being transferred to the inert gas, resulting in a high heat loss rate.

[0004] Another existing technology, CN120393868A, proposes using the tail gas produced by a fluidized bed reactor to directly participate in the heat exchange of nitrogen and carbon source gas, so as to preheat the gas for subsequent processes. However, due to the instability of the tail gas generation, this scheme makes it difficult to control the heat exchange process, and the preheating effect cannot be guaranteed, thus affecting production efficiency.

[0005] In addition, some processes recover waste heat by modifying the kiln structure, but such solutions have high equipment manufacturing and labor costs and are not economically viable. Summary of the Invention

[0006] To address the technical problems mentioned in the background section, the present invention provides a tail gas reuse system, characterized in that it is applied to a porous carbon preparation device, comprising: An incinerator, connected to the porous carbon preparation device, is used to incinerate the exhaust gas emitted by the porous carbon preparation device; A gas reservoir and a heat exchange device are connected to each other. The heat exchange device is connected to the incinerator. The saturated steam generated by the gas reservoir exchanges heat with the exhaust gas of the incinerator in the heat exchange device to produce superheated steam. At least part of the superheated steam is sent back to the porous carbon preparation device for the preparation of porous carbon.

[0007] By recycling superheated steam for the preparation of porous carbon, the heat recovery efficiency is significantly improved, the raw material cost and energy consumption of porous carbon preparation are reduced, and the tail gas treatment process is simplified. This effectively solves the problems of low heat recovery efficiency, high heat loss rate and unstable system operation in the existing technology, and realizes the efficient conversion of tail gas heat into activator steam.

[0008] Optionally, the heat exchange device includes a primary heat exchanger and a secondary heat exchanger. The exhaust gas inlet of the primary heat exchanger is connected to the incinerator, and the exhaust gas outlet is connected to the exhaust gas inlet of the secondary heat exchanger. The steam inlet of the primary heat exchanger is connected to the steam outlet of the gas drum, and the steam outlet of the primary heat exchanger is connected to the porous carbon preparation device. The primary heat exchanger receives saturated steam and uses the heat of the exhaust gas to prepare superheated steam for delivery to the porous carbon preparation device.

[0009] The two-stage heat exchange structure significantly improves heat recovery efficiency, enabling the system to operate stably and adapt to different working conditions. At the same time, it reduces the risk of thermal stress on the equipment and effectively solves the problems of insufficient heat recovery and unstable system operation caused by the inability of single-stage heat exchange structure to achieve cascade utilization of heat.

[0010] Optionally, it further includes: a flash evaporator having a hot water inlet and a steam outlet, the secondary heat exchanger having a hot water inlet and a hot water outlet; the hot water inlet of the flash evaporator being connected to the hot water outlet of the secondary heat exchanger, the steam outlet of the flash evaporator being connected to the first steam inlet of the gas chamber, the flash evaporator generating saturated steam and supplying it to the gas chamber.

[0011] The flash evaporation device stabilized the steam supply, ensured continuous system operation, and improved overall thermal efficiency, effectively solving the problem of unstable steam output caused by hot water temperature fluctuations after secondary heat exchange.

[0012] Optionally, it further includes: a level gauge for measuring the liquid level in the flash evaporator; a first regulating valve, communicatively connected to the level gauge, for adjusting the flow rate of the hot water inlet of the flash evaporator according to the liquid level signal of the level gauge; and a transfer pump is also provided between the flash evaporator and the secondary heat exchanger, the transfer pump also being communicatively connected to the level gauge.

[0013] Automatic liquid level control significantly improves the operational stability of the flash evaporator, ensures continuous production of saturated steam, and effectively solves the problem of unstable steam production caused by liquid level fluctuations in the flash evaporator.

[0014] Optionally, it further includes: a steam generator connected to a second steam inlet of the gas reservoir; a first pressure sensor communicatively connected to the steam generator for measuring the gas pressure at the steam outlet of the flash evaporation device; the steam generator generating saturated steam and supplying it to the gas reservoir; the steam generator shutting off after the pressure value measured by the first pressure sensor reaches a preset value and is maintained for a preset time.

[0015] The auxiliary steam generator ensures system startup and stable operation, improves overall reliability and energy efficiency, and effectively solves the problem of insufficient steam supply during system startup or low load.

[0016] Optionally, it further includes: a plate heat exchanger, wherein the hot water inlet of the plate heat exchanger is connected to the hot water outlet of the secondary heat exchanger, and the hot water outlet of the plate heat exchanger is connected to the hot water inlet of the flash evaporator, so that the flash evaporator and the secondary heat exchanger are connected through the plate heat exchanger; the plate heat exchanger also has a circulating water inlet and a circulating water outlet, and the plate heat exchanger uses circulating water for heat exchange to regulate the temperature of the hot water entering the flash evaporator.

[0017] The temperature regulation function stabilized the operating conditions of the flash tank, improved the overall system efficiency and stability, and effectively solved the problem of flash evaporation efficiency being affected by the temperature fluctuation of the hot water at the outlet of the secondary heat exchanger.

[0018] Optionally, it further includes: a temperature sensor for measuring the temperature of the hot water outlet pipeline of the plate heat exchanger; and a second regulating valve, communicatively connected to the temperature sensor, for controlling the flow rate of the hot water inlet pipeline of the plate heat exchanger based on the temperature signal from the temperature sensor.

[0019] Closed-loop control significantly improves temperature regulation accuracy, ensures stable system operation and efficient heat energy utilization, and effectively solves the problem of inaccurate temperature control of plate heat exchangers causing hot water temperature fluctuations that affect flash evaporation.

[0020] Optionally, it further includes: a second pressure sensor for measuring the pressure of the air tank; and a third regulating valve, which is communicatively connected to the second pressure sensor and is installed in the connecting pipeline between the air tank and the heat exchange device, wherein the third regulating valve controls the pressure of the air tank within the range of 1.5 to 3.0 barg according to the pressure signal provided by the second pressure sensor.

[0021] Automatic pressure control ensures stable operation of the steam tank, improves system reliability and the continuity of the activation process, and effectively solves the problem of steam tank pressure fluctuations affecting the stability of superheated steam supply.

[0022] Optionally, the temperature of the exhaust gas received at the exhaust gas inlet of the primary heat exchanger is 900~950℃; the temperature of the exhaust gas received at the exhaust gas inlet of the secondary heat exchanger is 500~600℃; the temperature of the exhaust gas discharged at the exhaust gas outlet of the secondary heat exchanger is 150~200℃; both the primary and secondary heat exchangers are vertical shell-and-tube heat exchangers, and the vertical shell-and-tube heat exchangers have fixed tube sheets and / or removable tube sheets; the exhaust gas reuse system further includes an exhaust gas environmental protection treatment device, and the exhaust gas outlet of the secondary heat exchanger is connected to the exhaust gas environmental protection treatment device; the incinerator uses air for combustion and natural gas as supplementary fuel.

[0023] By optimizing the temperature range, heat exchanger design, and combustion method, the heat recovery efficiency and system reliability have been significantly improved, while ensuring environmental compliance. This effectively solves the problems of low heat recovery efficiency caused by improper selection of heat exchanger temperature range and type, as well as low thermal efficiency and non-compliance with emission standards caused by incomplete combustion in the incinerator.

[0024] Another aspect of the present invention provides a porous carbon preparation system, characterized in that it comprises: Porous carbon preparation apparatus; The aforementioned exhaust gas reuse system is connected to the porous carbon preparation device.

[0025] By recycling superheated steam for the preparation of porous carbon, the energy consumption and raw material costs of porous carbon preparation are significantly reduced, the overall production efficiency is improved, and the problem of how to integrate the tail gas reuse system with the porous carbon preparation device to achieve overall energy saving and reduce production costs is effectively solved.

[0026] Another aspect of the present invention provides a method for reusing exhaust gas from porous carbon preparation, characterized by comprising the following steps: The exhaust gas emitted from the incineration of the porous carbon preparation; The heat from the exhaust gas after incineration is used to convert saturated steam into superheated steam. The obtained superheated steam is at least partially returned to the porous carbon preparation apparatus for the preparation of porous carbon.

[0027] This method significantly improves the efficiency of exhaust gas heat recovery, reduces steam consumption and energy costs in the porous carbon preparation process, simplifies the exhaust gas treatment process, and effectively solves the problem of how to efficiently recover the heat in the exhaust gas from porous carbon preparation and convert it into usable superheated steam.

[0028] Optionally, the step of converting saturated steam into superheated steam using the heat from the incinerated exhaust gas includes: passing the exhaust gas through a primary heat exchanger and using the heat exchanged between the exhaust gas and the primary heat exchanger to prepare superheated steam; passing the exhaust gas discharged from the primary heat exchanger through a secondary heat exchanger and using the heat exchanged between the exhaust gas and the secondary heat exchanger to prepare hot water; using at least a portion of the prepared hot water to prepare saturated steam by flash evaporation; and using the obtained saturated steam to prepare the superheated steam.

[0029] This design enables the cascade recovery of exhaust gas heat, improves heat utilization efficiency, ensures a stable supply of superheated steam, reduces system operating costs, and effectively solves the problem of how to ensure that exhaust gas heat is recovered efficiently in multiple stages and that superheated steam is stably produced.

[0030] Optionally, before the step of flashing at least part of the prepared hot water to prepare saturated steam, the method further includes: preparing saturated steam using a steam generator; supplying the saturated steam to a primary heat exchanger and using the heat exchanged by the exhaust gas in the primary heat exchanger to prepare superheated steam; after the step of flashing at least part of the prepared hot water to prepare saturated steam, the method further includes: obtaining the pressure value of the saturated steam prepared by flashing; and shutting off the steam generator after the measured pressure value reaches a preset value and is maintained for more than a preset time.

[0031] This method ensures the stability of system startup and operation, achieves seamless switching of steam supply, further reduces operating costs, and effectively solves the problem of how to achieve a smooth transition from system startup to stable operation and ensure the continuity and stability of steam supply.

[0032] In summary, this invention decomposes VOCs in the exhaust gas of an incinerator, releasing high-calorific-value heat. Combined with a multi-stage heat exchanger, it achieves cascaded heat recovery. Saturated steam generated in the gas drum is exchanged with the incinerator exhaust gas to produce superheated steam, which is then reused in the porous carbon preparation process. The system also integrates a flash evaporation device, an automatic level and temperature control system, and a pressure stabilization mechanism to ensure the continuity and stability of the steam supply. This invention systematically solves the problems of low heat recovery efficiency, high heat loss rate, and unstable system operation in the prior art, achieving efficient conversion of exhaust gas heat into activator steam. This significantly reduces energy consumption and raw material costs in porous carbon preparation, while simplifying the exhaust gas treatment process, providing an efficient, stable, and environmentally friendly waste heat recovery solution for porous carbon preparation. Attached Figure Description

[0033] To more clearly illustrate the embodiments of this patent, the relevant drawings will be briefly described below. It should be understood that the drawings described below are only for illustrating some embodiments of this patent, and those skilled in the art can obtain many other technical features and connections not mentioned herein based on these drawings.

[0034] Figure 1 This is a schematic diagram of an exhaust gas reuse system according to the first embodiment of this patent; Figure 2 This is a schematic diagram of a tail gas recycling system according to the second embodiment of this patent; Figure 3 This is a schematic diagram of a tail gas recycling system according to the third embodiment of this patent; Figure 4 This is a schematic diagram of a tail gas recycling system according to the fourth embodiment of this patent; Figure 5 This is a schematic diagram of a tail gas recycling system according to the fifth embodiment of this patent; Figure 6 This is a flowchart of a method for reusing exhaust gas from porous carbon preparation according to an embodiment of this patent. Figure 7 This is a flowchart of a method for reusing exhaust gas from porous carbon preparation according to an embodiment of this patent. Figure 8 This is a flowchart of a method for reusing exhaust gas from porous carbon preparation according to an embodiment of this patent.

[0035] Explanation of reference numerals in the attached figures: 1. Incinerator; 2. Primary heat exchanger; 3. Secondary heat exchanger; 4. Gas manifold; 41. Pressure regulating valve; 42. First pressure sensor; 43. Second pressure sensor; 44. Temperature sensor; 5. Rotary kiln system; 6. Tail gas treatment device; 7. Flash evaporator; 71. Level gauge; 72. First regulating valve; 8. Plate heat exchanger; 9. Steam generator; 10. Ground tank. Detailed Implementation

[0036] The patent will now be described in detail with reference to the accompanying drawings.

[0037] In the industrial-scale preparation of porous carbon materials, exhaust gas treatment and heat recovery constitute indispensable parts of the production system. As the skeletal carrier of silicon-carbon anode materials, the preparation of porous carbon typically involves high-temperature carbonization and activation reactions, resulting in high-temperature exhaust gases containing volatile organic compounds. These exhaust gases not only require purification to meet environmental emission standards, but the effective recovery and utilization of the large amount of heat energy they contain will significantly reduce production energy consumption and improve system economic efficiency. In typical processes, the exhaust gas treatment system and heat recovery device together form a complete chain of exhaust gas purification and energy reuse, playing a decisive role in ensuring the economic efficiency and environmental friendliness of the production process.

[0038] In a widely used existing technical solution, the common approach is to recover waste heat from tail gas and use it directly to preheat process gases. Specifically, the tail gas is treated by a multi-stage scrubbing tower and then introduced into a heat exchanger to exchange heat with inert gas, thereby preheating the process gas. Although this process can partially recover heat from the tail gas, its core design relies on direct heat exchange between the tail gas and the process gas, and the tail gas must be purified by scrubbing towers before entering the heat exchanger. In this solution, the tail gas first undergoes wet purification through multiple scrubbing towers, then enters the heat exchanger to exchange heat with inert gas, and finally the preheated inert gas is introduced into the reactor to participate in subsequent process steps.

[0039] However, this scheme inherently requires the exhaust gas to undergo wet scrubbing, which directly results in a significant amount of heat energy being absorbed by the scrubbing liquid and failing to be effectively recovered. The high-grade heat energy contained in the exhaust gas is drastically reduced due to the scrubbing process, with only a small amount of heat transferred to the process gas through the heat exchanger, leading to low overall heat recovery efficiency. While direct contact between water and exhaust gas in the scrubbing tower can effectively remove pollutants, it also causes a sharp drop in exhaust gas temperature, significantly reducing the effective temperature difference available for heat exchange and fundamentally limiting the overall thermal utilization efficiency of the system.

[0040] A deeper analysis reveals that this design separates exhaust gas treatment and heat recovery into two independent stages, leading to a serious functional contradiction within the system: on the one hand, to ensure exhaust gas meets emission standards, wet purification via a scrubbing tower is necessary, significantly reducing the exhaust gas temperature; on the other hand, to achieve effective heat recovery, a relatively high exhaust gas temperature needs to be maintained to ensure heat exchange efficiency. This inherent contradiction prevents the system from simultaneously meeting environmental requirements and energy efficiency, ultimately resulting in a dual predicament of low heat recovery rate and increased production costs. In actual operation, this problem manifests as increased system heat load, increased steam consumption, and persistently high energy costs in the porous carbon preparation process.

[0041] To address the aforementioned problems, those skilled in the art might initially consider improving heat recovery efficiency by optimizing the scrubbing tower design or increasing the heat exchange area. For example, an additional heat exchanger could be added after the scrubbing tower, or a heat recovery stage could be incorporated into the scrubbing liquid circulation system. However, such improvements essentially fail to solve the problem of significant heat loss caused by wet scrubbing and significantly increase system complexity and investment costs. More importantly, due to the thermodynamic characteristics of the scrubbing process itself, a large amount of heat from the exhaust gas is absorbed by the scrubbing liquid, leaving extremely limited heat recovery by subsequent heat exchangers. This results in very low marginal benefits for such improvements, failing to fundamentally solve the problem of low heat recovery efficiency.

[0042] In view of this, embodiments of the present invention aim to provide an exhaust gas reuse system in order to solve or at least partially alleviate the above-mentioned technical problems.

[0043] First Implementation Method refer to Figure 1 The present invention provides, in one aspect, a tail gas reuse system applied to a porous carbon preparation apparatus, comprising: Incinerator 1, connected to the porous carbon preparation device, is used to incinerate the exhaust gas emitted by the porous carbon preparation device; The gas reservoir 4 and the heat exchange device are connected to each other. The heat exchange device is connected to the incinerator 1. The saturated steam generated by the gas reservoir 4 and the tail gas of the incinerator 1 exchange heat in the heat exchange device to produce superheated steam. At least part of the superheated steam is sent back to the porous carbon preparation device for the preparation of porous carbon.

[0044] Another aspect of the present invention provides a porous carbon preparation system, comprising: a porous carbon preparation apparatus; The aforementioned exhaust gas reuse system is connected to a porous carbon preparation device.

[0045] refer to Figure 6 The present invention also provides a method for reusing exhaust gas from porous carbon preparation, comprising the following steps: S1, exhaust gas emitted from the incineration of porous carbon; S2. Utilize the heat of the exhaust gas after combustion to convert saturated steam into superheated steam; S3. At least a portion of the obtained superheated steam is returned to the porous carbon preparation apparatus for the preparation of porous carbon.

[0046] Among them, reference Figure 7 As shown, the specific steps in converting saturated steam into superheated steam using the heat from incineration exhaust gas include: S4. Pass the exhaust gas through the first-stage heat exchanger 2, and use the heat exchanged by the exhaust gas in the first-stage heat exchanger 2 to prepare superheated steam. S5. The exhaust gas discharged from the primary heat exchanger 2 is passed through the secondary heat exchanger 3, and hot water is prepared by using the heat exchanged by the exhaust gas in the secondary heat exchanger 3. S6. Prepare saturated steam by flash evaporation, at least in part, of the prepared hot water; S7. Use the obtained saturated steam to prepare the superheated steam.

[0047] In addition, the heat exchange device includes a primary heat exchanger 2 and a secondary heat exchanger 3. The tail gas inlet of the primary heat exchanger 2 is connected to the incinerator 1, and the tail gas outlet is connected to the tail gas inlet of the secondary heat exchanger 3. The steam inlet of the primary heat exchanger 2 is connected to the steam outlet of the gas drum 4, and the steam outlet of the primary heat exchanger 2 is connected to the porous carbon preparation device. The primary heat exchanger 2 receives saturated steam and uses the heat of the tail gas to prepare superheated steam for delivery to the porous carbon preparation device.

[0048] To address the problem of low efficiency in exhaust gas heat recovery, an innovative system architecture has been proposed: the system can include an organic combination of an incinerator 1, a gas reservoir 4, and a heat exchanger. For example, the incinerator 1 can be connected to a porous carbon preparation device for incinerating the exhaust gas emitted during the porous carbon preparation process; the gas reservoir 4 can be connected to the heat exchanger, which in turn can be connected to the incinerator 1, allowing the saturated steam generated by the gas reservoir 4 to exchange heat with the exhaust gas of the incinerator 1 in the heat exchanger to produce superheated steam; this superheated steam can be at least partially returned to the porous carbon preparation device for the preparation of porous carbon. In a specific embodiment, the incinerator 1 can be made of high-temperature resistant stainless steel, and its inner wall can be coated with a refractory ceramic coating to improve thermal efficiency. Simultaneously, the combustion chamber of the incinerator 1 can be equipped with natural gas nozzles and an air-assisted combustion system to ensure that volatile organic compounds in the exhaust gas are fully decomposed. The gas reservoir 4 can be designed as a horizontal pressure vessel, with internal baffles to reduce steam fluctuations. The heat exchanger can adopt a shell-and-tube structure, where saturated steam flows in the tubes and exhaust gas flows in the shell. For optimal performance, the pressure of the gas reservoir 4 can be controlled within the range of 1.0 to 3.0 barg, ideally around 2 barg. This can be achieved through interlocking control of a pressure sensor and a regulating valve.

[0049] The innovation of this system architecture lies in integrating exhaust gas treatment and heat recovery into a continuous process, rather than treating them separately as in traditional solutions. For example, incinerator 1 not only effectively decomposes volatile organic compounds in the exhaust gas but also releases high-calorific-value heat, providing a stable heat source for subsequent heat recovery. The connection design between the gas reservoir 4 and the heat exchanger creates a heat transfer path, enabling the exhaust gas heat to be efficiently converted into superheated steam. The scheme of recycling the superheated steam to the porous carbon preparation device directly converts the recovered heat into the activator required for production, thereby reducing the consumption of fresh steam. This design cleverly avoids the problem of significant heat loss caused by wet scrubbing in traditional systems, because the exhaust gas does not need to be treated by a scrubbing tower before entering the heat exchanger, thus retaining the high-grade heat energy of the exhaust gas and significantly improving heat exchange efficiency. In addition, the system can achieve steam self-sufficiency. Once the system is operating stably, it can not only meet the activator requirements of the porous carbon preparation process but may also generate excess superheated steam for use in other areas of the plant.

[0050] To further optimize the efficiency of thermal energy utilization, the system can be further configured to include a two-stage heat exchanger structure. For example, the heat exchange device may include a primary heat exchanger 2 and a secondary heat exchanger 3. The exhaust gas inlet of the primary heat exchanger 2 can be connected to the incinerator 1, and the exhaust gas outlet can be connected to the exhaust gas inlet of the secondary heat exchanger 3. Simultaneously, the steam inlet of the primary heat exchanger 2 can be connected to the steam outlet of the gas drum 4, and its steam outlet can be connected to a porous carbon preparation device. In one embodiment, the primary heat exchanger 2 can be made of high-temperature alloy steel to withstand high-temperature exhaust gas of 900-950°C, while the secondary heat exchanger 3 can be made of carbon steel to handle medium-temperature exhaust gas of 500-600°C. The tube side of the primary heat exchanger 2 can carry saturated steam, and the shell side can carry high-temperature exhaust gas, thereby directly producing superheated steam; the shell side of the secondary heat exchanger 3 can carry exhaust gas, and the tube side can carry hot water to recover heat from the medium-temperature exhaust gas. To achieve the best results, a temperature buffer zone can be set between the primary heat exchanger 2 and the secondary heat exchanger 3 to smooth out temperature fluctuations and ensure stable system operation.

[0051] This two-stage heat exchange structure design solves the problem of single-stage heat exchange failing to achieve tiered heat utilization, enabling the system to extract heat from the exhaust gas in stages. For example, the high-temperature exhaust gas first passes through the primary heat exchanger 2, transferring heat to saturated steam to produce superheated steam, meeting the activation requirements for porous carbon preparation. Subsequently, the cooled exhaust gas enters the secondary heat exchanger 3, transferring the remaining heat to the hot water to provide a heat source for the subsequent flash evaporation process. This design not only significantly improves heat recovery efficiency but also allows the system to adapt to different operating conditions, as each stage of the heat exchanger can be independently adjusted according to actual temperature changes. More importantly, this tiered heat exchange method reduces the risk of thermal stress on the equipment and extends its service life, because heat is extracted gradually rather than exchanged all at once, avoiding damage to the equipment caused by sudden temperature changes. Furthermore, this design reserves space for future system expansion, such as adding an intermediate heat exchanger between the two stages to further improve heat recovery efficiency.

[0052] When the aforementioned tail gas reuse system is integrated with the porous carbon preparation device, a complete porous carbon preparation system can be formed. For example, the porous carbon preparation device can be a rotary kiln system 5, whose tail gas outlet can be directly connected to the inlet of the incinerator 1; while the tail gas reuse system can be connected to the activation section of the rotary kiln system 5 to realize the reuse of superheated steam. In one embodiment, the rotary kiln system 5 can include a carbonization zone and an activation zone, wherein the carbonization zone can be carried out under a nitrogen atmosphere, and the activation zone can be supplied with superheated steam provided by the tail gas reuse system. The connecting pipe between the rotary kiln and the incinerator 1 can be equipped with temperature and flow monitoring devices to ensure stable tail gas delivery; while the steam pipe between the gas tank 4 and the activation zone of the rotary kiln can be equipped with a pressure regulating valve 41 and a flow meter to precisely control the amount of activation steam used. To obtain the best results, the entire system can be equipped with a central monitoring unit to coordinate the porous carbon preparation process and the tail gas treatment process, and realize the automatic optimization of production parameters.

[0053] This design, which reuses superheated steam to prepare porous carbon, seamlessly integrates tail gas treatment with the porous carbon preparation process, significantly reducing energy consumption and raw material costs. For example, by directly connecting the tail gas reuse system to the porous carbon preparation unit, the system can respond in real time to changes in steam demand during production, ensuring the continuity and stability of the activation process. More importantly, this integrated design not only reduces the consumption of fresh steam but also lowers the heat load of the rotary kiln system 5, as some of the heat is provided by the recovered tail gas. Furthermore, the system enables closed-loop management of energy flow, converting tail gas, which would otherwise be waste, into valuable thermal energy resources, thereby improving the energy efficiency of the entire production system. This design also provides interfaces for future system optimization, such as connecting excess superheated steam to other equipment in the plant that requires heat energy, further expanding energy-saving benefits.

[0054] Furthermore, in actual operation, the system can reuse the exhaust gas in the following way. First, the exhaust gas emitted from the porous carbon preparation can be incinerated to remove volatile organic compounds (VOCs). Then, the heat from the incinerated exhaust gas can be used to convert saturated steam into superheated steam. Finally, at least a portion of the superheated steam can be transported back to the porous carbon preparation device for the preparation of porous carbon. In a specific embodiment, the incineration process can be carried out at a temperature of 900-950°C. VOCs in the exhaust gas can be completely decomposed into H2O and CO2 under the conditions of air combustion and natural gas as supplementary fuel. The saturated steam can enter the primary heat exchanger 2 at a pressure of 2 barg, and after heat exchange with the high-temperature exhaust gas, it can be converted into superheated steam. This superheated steam can be at least partially transported back to the activation zone of the rotary kiln system 5 as an activator. To obtain the best results, the system can be configured with an automatic switching mechanism between the start-up phase and the stable operation phase. For example, when the system starts up, the steam generator 9 provides initial saturated steam, and after the system stabilizes, it automatically switches to saturated steam provided by the flash tank.

[0055] The innovation of this method lies in the organic integration of tail gas treatment and steam generation, achieving efficient recovery and utilization of thermal energy. Incineration of tail gas not only solves environmental problems but also releases a large amount of thermal energy, providing a stable heat source for subsequent heat exchange. By converting saturated steam into superheated steam, the system can directly convert the recovered heat into the activator required for production, thereby reducing the consumption of fresh steam. The design of recycling superheated steam to the porous carbon preparation device achieves closed-loop energy utilization, reducing the overall energy consumption of the system. This design cleverly overcomes the contradiction between tail gas treatment and thermal energy recovery in traditional systems, because the tail gas does not need to be treated by a scrubbing tower before entering the heat exchange device, thus retaining the high-grade thermal energy of the tail gas. Furthermore, this method simplifies the tail gas treatment process, as the incineration process decomposes VOCs into harmless substances, requiring only simple desulfurization and denitrification treatment to meet emission standards, thereby reducing the complexity and cost of tail gas treatment.

[0056] Furthermore, the tail gas temperature received at the tail gas inlet of the first-stage heat exchanger 2 is 900~950℃; the tail gas temperature received at the tail gas inlet of the second-stage heat exchanger 3 is 500~600℃; the tail gas temperature discharged from the tail gas outlet of the second-stage heat exchanger 3 is 140~200℃; both the first-stage heat exchanger 2 and the second-stage heat exchanger 3 are vertical shell-and-tube heat exchangers, and the vertical shell-and-tube heat exchangers have fixed tube sheets and / or removable tube sheets; the tail gas reuse system also includes a tail gas environmental protection treatment device, and the tail gas outlet of the second-stage heat exchanger 3 is connected to the tail gas environmental protection treatment device; the incinerator 1 uses air for combustion and natural gas as supplementary fuel.

[0057] In the aforementioned exhaust gas reuse system, to achieve synergistic optimization of heat recovery efficiency and environmental compliance, the temperature parameters of the primary heat exchanger 2 and the secondary heat exchanger 3, the heat exchanger structural design, and the combustion mode of the incinerator 1 are specifically configured. For example, the exhaust gas inlet temperature of the primary heat exchanger 2 can be controlled within the range of 900~950℃, where 900℃ and 950℃ are the lower and upper limits of this range, respectively, and 925℃ can be considered a preferred intermediate value within this range; the exhaust gas inlet temperature of the secondary heat exchanger 3 can be maintained within the range of 500~600℃, where the lower limit of 500℃ and the upper limit of 600℃ correspond to the heat exchange starting point under different operating conditions, and 550℃ can be considered a typical operating temperature within this range; the exhaust gas outlet temperature of the secondary heat exchanger 3 can be adjusted to the range of 140~200℃, where 140℃ and 200℃ are the boundary values ​​of this range, and 175℃ can be considered a preferred intermediate value within this range to ensure sufficient cooling of the exhaust gas. In practice, these temperature parameters can be monitored in real time by thermocouple sensors distributed in the pipeline, and the combustion intensity and heat exchange medium flow rate of incinerator 1 can be dynamically adjusted by the closed-loop control system.

[0058] Furthermore, both the primary heat exchanger 2 and the secondary heat exchanger 3 can adopt a vertical shell-and-tube heat exchanger structure. Their tube sheet design can be either a fixed tube sheet or a removable tube sheet. The removable tube sheet allows for cleaning of accumulated dust without shutting down the system, while the fixed tube sheet structure is suitable for low-dust conditions to reduce maintenance frequency. In one embodiment, the shell side of the heat exchanger can be equipped with a high-temperature alloy liner to withstand exhaust gas impacts above 900°C, while the tube side uses 316L stainless steel tube bundles to enhance corrosion resistance. In another embodiment, an expansion joint structure can be added between the tube sheet and the shell to accommodate thermal stress changes caused by temperature fluctuations. Additionally, the exhaust gas outlet of the secondary heat exchanger 3 can be connected to an exhaust gas environmental treatment device. This device can include a catalytic oxidation unit and an activated carbon adsorption layer. The inlet temperature of the catalytic oxidation unit can be maintained at 180~200°C to activate the catalyst, while the activated carbon adsorption layer can be used to capture residual trace organic matter. For example, incinerator 1 can utilize air for combustion and natural gas as supplementary fuel. The air-to-natural gas mixing ratio can be dynamically adjusted based on the calorific value of the exhaust gas to ensure that the VOCs decomposition efficiency exceeds 99.5%. In a specific implementation, the combustion chamber of incinerator 1 can be equipped with multi-point gas nozzles, and its natural gas flow rate can be controlled by feedback from an oxygen content sensor. When the oxygen concentration in the exhaust gas is detected to be below 5%, the gas supply is automatically increased. In another embodiment, the combustion air of incinerator 1 can be preheated to 200-300°C to improve combustion stability and thermal efficiency. Simultaneously, the exhaust gas environmental treatment device can integrate a temperature monitoring module. When the exhaust gas temperature at the outlet of the secondary heat exchanger 3 is below 160°C, a heating compensation mechanism is automatically triggered to ensure that subsequent treatment units operate within the optimal temperature window.

[0059] This temperature gradient design enables stepwise recovery of heat from the exhaust gas. The first-stage heat exchanger 2 directly generates superheated steam in the high-temperature section to meet activation requirements, while the hot water produced in the mid-temperature section of the second-stage heat exchanger 3 is converted into saturated steam to supplement the system via flash evaporation device 7, thus significantly improving thermal energy utilization efficiency. Precise control of temperature parameters not only avoids the thermal stress risks inherent in traditional single-stage heat exchangers but also creates ideal reaction conditions for the environmental treatment device through an exhaust gas outlet temperature of 150~200℃, significantly reducing subsequent treatment energy consumption.

[0060] The heat exchanger adopts a vertical shell-and-tube structure with a removable tube sheet. Its ingenious design combines ease of maintenance with high heat exchange efficiency: when the heat transfer coefficient decreases due to dust accumulation on the tube sheet after a period of system operation, it can be quickly disassembled and cleaned without affecting the overall process. This solves the problem of heat recovery rate degradation caused by dust accumulation in existing technologies. Compared to a fixed tube sheet design, the removable solution can extend equipment life by more than 30% under frequent start-stop conditions while maintaining stable heat exchange efficiency.

[0061] The core innovation of the air-assisted combustion and natural gas supplementary fuel combination in incinerator 1 lies in dynamically balancing combustion completeness and energy consumption: by adjusting the fuel ratio through real-time monitoring of exhaust gas composition, it ensures complete decomposition of VOCs while avoiding energy waste caused by excessive fuel. This design cleverly overcomes the technical bias of incomplete combustion in traditional incinerator 1 under low-calorific-value exhaust gas conditions, enabling the system to maintain environmentally compliant emissions across a wide load range, while providing a stable heat source for subsequent heat exchange processes.

[0062] Second Implementation Method refer to Figure 2 As shown, the improvement of the second embodiment of this application compared with the first embodiment is that the system further includes: a flash evaporator 7 having a hot water inlet and a steam outlet, and a secondary heat exchanger 3 having a hot water inlet and a hot water outlet; the hot water inlet of the flash evaporator 7 is connected to the hot water outlet of the secondary heat exchanger 3, and the steam outlet of the flash evaporator 7 is connected to the first steam inlet of the gas chamber 4; the flash evaporator 7 prepares saturated steam and supplies it to the gas chamber 4.

[0063] Furthermore, the system also includes: a level gauge 71 for measuring the liquid level in the flash evaporator 7; a first regulating valve 72, which is communicatively connected to the level gauge 71 and is used to adjust the flow rate of the hot water inlet of the flash evaporator 7 according to the liquid level signal of the level gauge 71; and a transfer pump is also provided between the flash evaporator 7 and the secondary heat exchanger 3, which is also communicatively connected to the level gauge 71.

[0064] In addition, refer to Figure 8 As shown, prior to the step of flash evaporating at least part of the prepared hot water to prepare saturated steam, the method further includes: S8. Use steam generator 9 to prepare saturated steam; S9. Saturated steam is delivered to the first-stage heat exchanger 2, and superheated steam is prepared by using the heat exchanged by the tail gas in the first-stage heat exchanger 2. S10. After the step of preparing saturated steam by flash evaporation of at least part of the prepared hot water, the method further includes: S11. Obtain the pressure value of the saturated steam prepared by flash evaporation; S12. When the measured pressure value reaches the preset value and the duration exceeds the preset time, turn off the steam generator 9.

[0065] In the multi-stage waste heat recovery path, the hot water generated after the secondary heat exchange can achieve efficient thermal energy conversion and recycling through the flash evaporator 7. Specifically, the hot water inlet of the flash evaporator 7 is connected to the hot water outlet of the secondary heat exchanger 3, and its steam outlet is fluidly connected to the first steam inlet of the gas chamber 4, thereby continuously replenishing the saturated steam generated during the flash evaporation process into the gas chamber 4. In one embodiment, the flash evaporator 7 can adopt a horizontal storage tank structure, the internal space of which can be configured to achieve gas-liquid phase separation under specific pressure conditions; the hot water inlet pipeline of the storage tank can be located in the lower part of the tank body, while the steam outlet pipeline is arranged at the top of the tank body to ensure effective separation of steam and liquid. The operating pressure of the flash evaporator 7 can be maintained in the range of 1.5~3.0 barg, for example, through dynamic control by a pressure regulating valve 41, thereby converting superheated water into saturated steam under depressurization conditions. In some embodiments, the inner wall of the flash evaporator 7 may be provided with an anti-scaling coating, such as a ceramic matrix composite coating, to extend the equipment operating cycle; a drain port may be designed at its bottom for periodically removing any impurities that may accumulate. The drain port is drained every 3 months, and the drain port may be selectively connected to the ground tank 10 for subsequent treatment.

[0066] The design of the flash evaporator 7 cleverly solves the problem of unstable steam production caused by hot water temperature fluctuations after secondary heat exchange. By converting waste heat into saturated steam and directly supplementing it to the steam drum 4, the system can maintain a stable steam supply capacity, thereby ensuring the continuity of the subsequent superheated steam preparation process. In particular, this design avoids the drawback of traditional systems that require additional fresh steam to be added due to hot water temperature fluctuations, achieving closed-loop utilization of thermal energy. The pressure-temperature correspondence during the flash evaporation process allows the system to automatically adapt to changes in hot water flow rate. For example, when the hot water temperature increases, the flash evaporation rate increases accordingly, thereby dynamically balancing the steam output. This adaptive characteristic significantly improves the thermal efficiency of the entire waste heat recovery system while reducing the dependence on the initial steam reserve of the steam drum 4.

[0067] To further enhance the operational stability of the flash evaporator 7, its liquid level can be precisely adjusted through an automated control system. For example, a level gauge 71 can be installed on the side wall of the flash evaporator 7 to monitor the liquid level in the tank in real time. The level gauge 71 can be a differential pressure sensor, and its output signal can be transmitted to the control unit of the first regulating valve 72. The first regulating valve 72 can be installed on the hot water inlet pipeline of the flash evaporator 7 to dynamically adjust the hot water flow rate according to the signal fed back by the level gauge 71. For example, when the liquid level is higher than a set threshold, the regulating valve can automatically reduce the opening to reduce the inlet water flow; when the liquid level is lower than the set threshold, the opening can be increased to supplement the water flow. In addition, a transfer pump can be configured in the pipeline between the flash evaporator 7 and the secondary heat exchanger 3. This transfer pump also establishes a communication connection with the level gauge 71, for example, through linkage via a PLC control system. In some embodiments, the transfer pump can selectively adopt a variable frequency drive to precisely adjust the delivery flow rate according to changes in liquid level, thereby enhancing the system's responsiveness to dynamic operating conditions.

[0068] The innovation of this automatic liquid level control mechanism lies in its ability to achieve dynamic balance of the liquid level within the flash evaporator 7 through closed-loop feedback. Real-time data provided by the level gauge 71 allows the system to predict steam production trends. For example, when a rapid drop in liquid level is detected, the control system can increase the hot water supply in advance to avoid interruption of steam production. The coordinated operation of the delivery pump and the regulating valve forms a dual regulation mechanism, capable of handling both sudden flow changes and smoothing out minor fluctuations. This design effectively overcomes the problem of unstable steam pressure caused by liquid level fluctuations in traditional systems. In particular, this control strategy exhibits significant advantages when the system load changes. For instance, when the activation demand of the porous carbon preparation device increases, the system can rapidly increase steam production by increasing the hot water flow rate without experiencing the sudden pressure drop common in traditional systems.

[0069] In the overall process of waste heat recovery from exhaust gas, the exhaust gas emitted by the porous carbon preparation device is treated by incinerator 1, and the heat released is systematically converted into usable thermal energy. Specifically, the exhaust gas first completes the decomposition of VOCs in incinerator 1. This process can be aided by air combustion and supplemented by natural gas as a supplementary fuel, thereby converting the organic matter in the exhaust gas into CO2 and H2O and releasing high-calorific-value heat. Subsequently, the heat of the exhaust gas after incineration is used to convert the saturated steam generated by gas drum 4 into superheated steam in a heat exchange device. Finally, this superheated steam can be at least partially transported back to the porous carbon preparation device to directly participate in the porous carbon preparation process as an activator. In one embodiment, the combustion temperature of the incinerator 1 can be controlled within the range of 800~1000℃, for example, by adjusting the natural gas flow rate and air ratio; the primary heat exchanger 2 can receive tail gas at a temperature of 900~950℃ and exchange it with saturated steam at about 2 barg to produce superheated steam at a temperature of 300~400℃; the superheated steam can be directly transported to the rotary kiln system 5 through pipeline for the activation process of porous carbon.

[0070] The core advantage of this method lies in its organic integration of exhaust gas treatment and heat recovery, rather than simply using heat to preheat the gas. Decomposing VOCs in the incinerator not only solves environmental problems but also releases a stable heat source for steam production; the direct reuse of superheated steam forms an energy closed loop, significantly reducing the consumption of fresh steam. In particular, this design overcomes the technical bias of low heat recovery efficiency in traditional systems. For example, when the VOCs concentration in the exhaust gas is low, the system can still ensure sufficient heat output through supplementary combustion of natural gas, thereby maintaining the continuity of steam production. This integrated "treatment-recovery-reuse" process not only reduces the energy consumption of porous carbon production but also simplifies the exhaust gas treatment process, avoiding heat loss problems caused by equipment such as scrubbing towers.

[0071] From the perspective of system operation economy, the superheated steam reuse mechanism creates significant dual benefits. On the one hand, the demand for activator steam (which refers to superheated steam used in the porous carbon activation process) in the rotary kiln system 5 can be fully met by the system's own production. For example, under stable operating conditions, approximately 1.5 tons of fresh steam consumption can be reduced per ton of porous carbon product. On the other hand, excess superheated steam can also be used in other areas of the plant, such as for plant heating or process heating. This design cleverly transforms environmental treatment costs into energy benefits, resolving the inherent contradiction of "increased energy consumption for treating exhaust gas" in traditional technologies. Crucially, this method ensures the system's adaptability to different operating conditions through a multi-stage heat recovery path. For example, when exhaust gas flow fluctuates, the synergistic effect of the secondary heat exchanger 3 and the flash evaporator 7 can maintain the stability of steam supply, thereby ensuring the consistency of porous carbon product quality.

[0072] To further improve thermal energy utilization and stabilize steam supply, the system may also include a flash evaporator 7, which has a hot water inlet and a steam outlet. The hot water inlet is connected to the hot water outlet of the secondary heat exchanger 3, and the steam outlet is connected to the steam inlet of the steam drum 4. For example, the flash evaporator 7 can be designed as a horizontal tank structure, with its hot water inlet connected to the hot water outlet pipeline of the secondary heat exchanger 3 via a standard flange; the steam outlet of the tank can be connected to the supplementary steam inlet of the steam drum 4 via an insulated steam pipe. In some embodiments, the inner cavity of the flash evaporator 7 can be equipped with a pressure balancing pipe to maintain internal pressure stability during depressurized flash evaporation; its inner wall can be lined with an anti-erosion lining to withstand the impact of high-speed hot water entry. Preferably, the flash evaporator 7 can be made of 304 stainless steel to resist hot water corrosion, and its volume can be dynamically adjusted according to the system heat load, for example, selected in the range of 5-15 m³. By introducing the hot water produced by the secondary heat exchanger 3 into the flash evaporator 7 for depressurized flash evaporation, the waste heat in the hot water can be converted into saturated steam. This saturated steam, after being replenished to the steam reservoir 4, can maintain the stability of the total steam volume within the reservoir 4. This design not only improves the overall heat recovery efficiency of the system but also avoids the waste caused by the direct discharge of heat carried in the hot water, thus ensuring a continuous and stable supply of superheated steam. In particular, when the outlet hot water temperature of the secondary heat exchanger 3 fluctuates, the flash evaporator 7 can absorb heat fluctuations through the phase change process, effectively smoothing out system pressure changes and ensuring the continuity of the subsequent activation process.

[0073] To ensure stable liquid level in the flash evaporator 7, the device can also be equipped with an automatic liquid level control system. For example, the liquid level gauge 71 can be a differential pressure sensor, installed at the top and bottom of the flash evaporator 7 to measure the liquid level height; the first regulating valve 72 can be configured on the hot water inlet pipeline of the flash evaporator 7, forming a closed-loop control circuit with the liquid level gauge 71. In some embodiments, a transfer pump can be installed between the flash evaporator 7 and the secondary heat exchanger 3. This transfer pump is also communicatively connected to the liquid level gauge 71 to assist in regulating the hot water flow rate; the speed of the transfer pump can be dynamically adjusted according to the liquid level signal to enhance the response speed of flow regulation. Preferably, the regulating valve can be a pneumatic control valve, whose opening degree is adjusted in real time according to the liquid level signal using a PID algorithm, and the liquid level setting range can be flexibly configured between 30% and 70%. By monitoring the liquid level status in the flash evaporator 7 in real time through the liquid level gauge 71, and automatically adjusting the hot water inlet flow rate in conjunction with the regulating valve and the transfer pump, the liquid level can be maintained within the preset range. This automatic control mechanism effectively avoids the problem of unstable steam production caused by liquid level fluctuations, ensuring the continuity and reliability of the flash evaporation process. When the system load changes, this control strategy can quickly respond to fluctuations in hot water flow, preventing excessively high liquid levels from causing steam to carry water or excessively low liquid levels from causing dry burning, thereby significantly improving the operational stability of the entire system.

[0074] In the tail gas reuse method, to achieve cascaded heat recovery and stable superheated steam production, the following steps can be adopted. For example, the incinerated tail gas can first pass through a primary heat exchanger 2, using its high-temperature heat to heat saturated steam into superheated steam; then, the tail gas discharged from the primary heat exchanger 2 is introduced into a secondary heat exchanger 3, using its residual heat to heat water into hot water; in some embodiments, at least part of the prepared hot water can be subjected to reduced-pressure flash evaporation through a flash evaporator 7 to produce saturated steam; finally, the saturated steam is used as a heat source to produce superheated steam in the primary heat exchanger 2. Preferably, the flash evaporation process can be carried out at a pressure of 0.5-1.5 barg to obtain the optimal steam production efficiency; the steam outlet temperature of the primary heat exchanger 2 can be controlled within the range of 250-350℃ to meet the requirements of the activation process. This method, by utilizing tail gas heat in a staged manner, achieves cascaded energy recovery from high temperature to medium temperature, significantly improving thermal energy utilization efficiency. The primary heat exchanger 2 directly generates superheated steam to meet activation requirements, while the hot water recovered by the secondary heat exchanger 3 is converted into saturated steam through flash evaporation, forming a steam recycling mechanism. This design not only avoids heat waste but also ensures a stable supply of superheated steam, thereby reducing system operating costs and improving production efficiency. In particular, when the exhaust gas flow fluctuates, the flash evaporation stage acts as a buffer unit to absorb heat changes, keeping steam production stable and effectively solving the problem of activator supply interruption caused by discontinuous heat recovery in traditional systems.

[0075] Through the synergistic effect of the above technical solutions, the system can efficiently recover heat from the exhaust gas, achieving self-sufficiency in steam. This not only reduces the consumption of fresh steam but also lowers the energy consumption of the porous carbon preparation process, while ensuring continuous and stable system operation. In practical applications, this combined solution can improve heat recovery efficiency, significantly reduce the steam cost of porous carbon production, and provide waste heat resources for other areas of the plant, thereby creating multiple economic benefits.

[0076] Third Implementation Method refer to Figure 3As shown, the improvement of the third embodiment of this application compared to the second embodiment is that the system further includes: a steam generator 9 connected to the second steam inlet of the gas reservoir 4; a first pressure sensor 42, communicatively connected to the steam generator 9, used to measure the gas pressure at the steam outlet of the flash evaporator 7; the steam generator 9 generates saturated steam and delivers it to the gas reservoir 4; the steam generator 9 shuts down after the pressure value measured by the first pressure sensor 42 reaches a preset value and is maintained for a preset time. During system startup or low-load operation, to ensure the continuity and stability of steam supply, the exhaust gas reuse system can be further configured with an auxiliary steam generation and intelligent start-stop mechanism. Specifically, the steam generator 9 can supplement saturated steam to the gas reservoir 4 through the second steam inlet, while the first pressure sensor 42 monitors the steam outlet pressure status of the flash evaporator 7 in real time and controls the operating status of the steam generator 9 based on a preset pressure-time interlock logic. The steam generator 9 can be configured as an electrically heated auxiliary device, and its heating power can be dynamically adjusted according to the system startup requirements to quickly generate saturated steam. The steam generator 9 is connected to the second steam inlet of the gas reservoir 4 via an independent pipeline, continuously supplying saturated steam to the gas reservoir 4 during the initial operation phase of the system, thereby ensuring a stable steam source for the primary heat exchanger 2. The first pressure sensor 42 can be installed on the steam outlet pipeline of the flash evaporator 7, with a measurement range covering 0-5 barg and an accuracy preferably controlled within ±0.1 barg to ensure the reliability of the pressure data. In terms of control logic, the automatic shutdown condition of the steam generator 9 can be set as follows: when the pressure value measured by the first pressure sensor 42 reaches 2 barg and is maintained continuously for more than 5 minutes, the control unit automatically cuts off the energy supply to the steam generator 9. In some embodiments, the pressure sensor signal can be synchronously transmitted to the central monitoring system, and the operator can adjust the preset pressure threshold (e.g., 1.8-2.2 barg) or the maintenance time (e.g., 4-6 minutes) according to the actual operating conditions to adapt to porous carbon preparation devices of different scales.

[0077] This design cleverly resolves the steam supply contradiction during the system transition period: in the initial startup phase, the heat of the exhaust gas from incinerator 1 has not yet reached a stable level, and flash evaporation device 7 cannot immediately generate sufficient steam. At this time, steam generator 9 acts as a temporary heat source to avoid interruption of the activation process. When the steam pressure produced by flash evaporation device 7 consistently meets the standard, the automatic shutdown mechanism effectively prevents energy waste. This pressure-time dual-judgment logic not only overcomes the technical bias of traditional single-point pressure control being susceptible to instantaneous fluctuations, but also reserves space for process optimization through dynamic threshold settings. Its core ingenuity lies in intelligently decoupling the system's self-sufficiency capability from external energy supplementation, ensuring production continuity while allowing steam generator 9 to operate only when necessary, thereby significantly reducing the overall energy consumption of the system. Experimental data shows that after adopting this mechanism, the transition time from system startup to stable operation is shortened by about 40%, and the ineffective operation time of steam generator 9 is reduced by more than 65%, providing reliable thermal energy guarantee for the porous carbon preparation process.

[0078] Fourth Implementation Method refer to Figure 4 As shown, the improvement of the fourth embodiment of this application compared with the third embodiment is that the system further includes: a plate heat exchanger 8, the hot water inlet of the plate heat exchanger 8 is connected to the hot water outlet of the secondary heat exchanger 3, and the hot water outlet of the plate heat exchanger 8 is connected to the hot water inlet of the flash evaporator 7, so that the flash evaporator 7 and the secondary heat exchanger 3 are connected through the plate heat exchanger 8; the plate heat exchanger 8 also has a circulating water inlet and a circulating water outlet, and the plate heat exchanger 8 uses circulating water to exchange heat to regulate the temperature of the hot water entering the flash evaporator 7.

[0079] In addition, the system also includes: a temperature sensor 44 for measuring the temperature of the hot water outlet pipeline of the plate heat exchanger 8; and a second regulating valve, which is communicatively connected to the temperature sensor 44 and is used to control the flow rate of the hot water inlet pipeline of the plate heat exchanger 8 according to the temperature signal from the temperature sensor 44.

[0080] To precisely control the temperature of the hot water entering the flash evaporator 7 and maintain stable system operation, a plate heat exchanger 8 is added between the secondary heat exchanger 3 and the flash evaporator 7 in this exhaust gas reuse system. The hot water inlet of the plate heat exchanger 8 is connected to the hot water outlet of the secondary heat exchanger 3, while its hot water outlet is connected to the hot water inlet of the flash evaporator 7. A circulating water inlet and outlet are also configured to enable temperature fine-tuning. In a specific embodiment, the plate heat exchanger 8 can adopt a detachable stainless steel plate structure with a plate thickness ranging from 0.5 to 1.2 mm. Adjacent plates form heat exchange chambers with a flow channel width of 3 to 8 mm. This design facilitates addressing scaling issues caused by changes in water quality and allows for adaptation to different heat load requirements under varying operating conditions by changing the plate combinations. The circulating water system of the plate heat exchanger 8 can be equipped with a variable frequency water pump with a flow rate range of 10-50 m³ / h. The circulating water temperature can be adjusted to the range of 30-80℃ via an external heat source, thereby achieving precise control of the hot water temperature entering the flash evaporator 7 within ±2℃. In some embodiments, a temperature preheater can also be added to the circulating water loop. This preheater can be electrically heated or heated by steam. It automatically starts when the hot water temperature at the outlet of the secondary heat exchanger 3 is lower than a set threshold, thereby shortening the transition time for the system to reach stable operating conditions. It is worth mentioning that the hot water outlet pipeline of the plate heat exchanger 8 refers not only to the pipeline directly connected to the outlet of the plate heat exchanger 8, see [link to relevant documentation]. Figure 4 As shown, temperature sensor 44 is installed on the pipe section where plate heat exchanger 8 and secondary heat exchanger 3 meet. This pipe section also belongs to the hot water outlet pipe of plate heat exchanger 8. At this time, it measures the hot water temperature after plate heat exchanger 8 and secondary heat exchanger 3 meet.

[0081] The temperature regulation function of the plate heat exchanger 8 cleverly solves the flash evaporation efficiency problem caused by the temperature fluctuation of the hot water at the outlet of the secondary heat exchanger 3. By introducing an independent circulating water system, the system can control the temperature of the hot water that would otherwise directly enter the flash evaporation unit 7 within an optimized range of 85-95℃, avoiding situations where the water temperature in the secondary heat exchanger 3 is too high (e.g., exceeding 200℃), leading to a sudden increase in pressure in the flash tank or insufficient steam production due to excessively low water temperature. This design not only significantly improves the stability of the flash evaporation process but also increases the overall heat recovery efficiency of the system by 8-12% through precise temperature gradient management, while reducing the mechanical stress on the flash tank and extending the service life of the equipment. Particularly noteworthy is that this structure provides the system with dynamic adjustment capabilities. When the hot water temperature in the secondary heat exchanger 3 changes by ±15℃ due to fluctuations in exhaust gas flow, the plate heat exchanger 8 can suppress the temperature fluctuation within ±3℃ within 3-5 minutes, thus ensuring the continuity of the subsequent flash evaporation process.

[0082] To further improve temperature control accuracy, the system is equipped with a temperature sensing and flow regulation component on the hot water outlet pipeline of the plate heat exchanger 8. In one embodiment, the temperature sensor 44 can adopt a dual-redundant RTD design, with a measurement accuracy of ±0.5℃. Its installation position is 1.5-2.0 times the pipe diameter from the outlet flange of the plate heat exchanger 8 to ensure the representativeness of the measurement signal. The second regulating valve can be a pneumatic diaphragm regulating valve, with its flow capacity coefficient Cv value set to 50-150 according to the system's maximum flow rate. The valve core adopts a V-shaped cut structure to achieve linear flow characteristics at small openings. This regulating valve and the temperature sensor 44 form a closed-loop control system. When the sensor detects that the hot water outlet temperature deviates from the set value by ±1℃, the regulating valve can complete the opening adjustment within 2-3 seconds, restoring the temperature to the target range. In some embodiments, the regulating valve can also integrate a flow feedback compensation function. When the system load changes abruptly, the valve opening is dynamically corrected by real-time monitoring of hot water flow changes to avoid temperature oscillations caused by flow disturbances.

[0083] This closed-loop temperature control mechanism effectively overcomes the technical bias of lag in temperature regulation in traditional systems. By moving the temperature measurement point forward to the outlet of plate heat exchanger 8, the system can anticipate temperature change trends, rather than relying solely on pressure or level feedback within the flash tank for delayed adjustment. This "predictive control" strategy reduces hot water temperature fluctuations by more than 60%, directly translating into improved stability in flash steam production. More importantly, this design achieves refined control of energy flow through precise temperature management. When the plant's heat demand changes, the system can flexibly adjust the circulating water flow rate of plate heat exchanger 8 while maintaining stable operation of the flash tank, directing excess heat to other heat-consuming units within the plant. This maximizes the plant's overall energy efficiency while ensuring the continuity of the porous carbon preparation process. The ingenuity of this technical solution lies in upgrading temperature control from "result feedback" to "process intervention," fundamentally resolving the technical contradiction between hot water temperature fluctuations and flash efficiency.

[0084] Fifth Implementation Method refer to Figure 5 As shown, the improvement of the fifth embodiment of this application compared with the fourth embodiment is that the system further includes: a second pressure sensor 43 for measuring the pressure of the air chamber 4; a third regulating valve, which is communicatively connected to the second pressure sensor 43 and is installed in the connecting pipeline between the air chamber 4 and the heat exchange device, and the third regulating valve controls the pressure of the air chamber 4 within the range of 2.9~3.0 barg according to the pressure signal provided by the second pressure sensor 43.

[0085] Regarding pressure control of the steam drum 4, the system further integrates real-time monitoring and automatic adjustment mechanisms to ensure the stability of superheated steam output. For example, a second pressure sensor 43 can be installed on the top or side wall of the steam drum 4 to continuously collect pressure data inside the steam drum 4; a third regulating valve can be installed on the steam delivery pipeline between the steam drum 4 and the heat exchanger. This regulating valve can be configured with a pressure fluctuation suppression algorithm to dynamically respond to the real-time signal from the pressure sensor. In specific implementations, the pressure of the steam drum 4 can be controlled within the range of 2.9~3.0 barg. For example, when the system is in steady-state operation, the pressure can be maintained at the lower limit of 2.9 barg to ensure the basic steam flow rate, or at the upper limit of 3.0 barg to enhance the supply capacity under high-load conditions. Preferably, the pressure can be stabilized at around 2.95 barg, which helps to balance the continuity of steam supply and system energy efficiency. In addition, the opening control logic of the regulating valve can be adaptively adjusted based on historical pressure fluctuation data. For example, when a rapid pressure rise is detected, the valve opening can be finely adjusted in advance to avoid the impact of sudden pressure changes on the downstream activation process.

[0086] The design motivation for this pressure control mechanism stems from the direct impact of pressure fluctuations in gas reservoir 4 on the reliability of superheated steam supply. Especially when there are sudden changes in tail gas flow or temperature, the lack of dynamic adjustment will lead to interruption of activator steam, resulting in uneven pore structure in porous carbon. By forming a closed-loop control system with the pressure sensor and regulating valve, the system can actively compensate for changes in heat load. For example, during a brief drop in tail gas temperature in incinerator 1, the regulating valve can automatically reduce its opening to maintain stable pressure within gas reservoir 4, thereby preventing the activation process from being interrupted due to insufficient steam. The resulting benefits include: significantly improving the continuity of activator steam during porous carbon preparation, reducing batch product performance differences caused by pressure fluctuations, optimizing system reliability under dynamic operating conditions, and providing a stable heat source for subsequent process stages.

[0087] Finally, it should be noted that those skilled in the art will understand that many technical details have been presented in the embodiments of this patent to facilitate a better understanding of the invention. However, even without these technical details and various variations and modifications based on the above embodiments, the technical solutions claimed in the claims of this patent can be substantially achieved. Therefore, in practical applications, various changes can be made to the above embodiments in form and detail without departing from the spirit and scope of this patent.

Claims

1. A tail gas recycling system, characterized in that, Applications in porous carbon preparation apparatus include: An incinerator, connected to the porous carbon preparation device, is used to incinerate the exhaust gas emitted by the porous carbon preparation device; A gas reservoir and a heat exchange device are connected to each other. The heat exchange device is connected to the incinerator. The saturated steam generated by the gas reservoir exchanges heat with the exhaust gas of the incinerator in the heat exchange device to produce superheated steam. At least part of the superheated steam is sent back to the porous carbon preparation device for the preparation of porous carbon.

2. The exhaust gas reuse system according to claim 1, characterized in that, The heat exchange device includes a primary heat exchanger and a secondary heat exchanger. The tail gas inlet of the primary heat exchanger is connected to the incinerator, and the tail gas outlet is connected to the tail gas inlet of the secondary heat exchanger. The steam inlet of the primary heat exchanger is connected to the steam outlet of the gas drum, and the steam outlet of the primary heat exchanger is connected to the porous carbon preparation device. The primary heat exchanger receives saturated steam and uses the heat from the exhaust gas to prepare superheated steam, which is then supplied to the porous carbon preparation apparatus.

3. The exhaust gas reuse system according to claim 2, characterized in that, Also includes: The flash evaporator has a hot water inlet and a steam outlet, and the secondary heat exchanger has a hot water inlet and a hot water outlet; The hot water inlet of the flash evaporator is connected to the hot water outlet of the secondary heat exchanger, and the steam outlet of the flash evaporator is connected to the first steam inlet of the gas chamber. The flash evaporator generates saturated steam and supplies it to the gas chamber.

4. The exhaust gas reuse system according to claim 3, characterized in that, Also includes: A level gauge is used to measure the liquid level inside the flash evaporation device; The first regulating valve is communicatively connected to the level gauge and is used to adjust the flow rate of the hot water inlet of the flash evaporation device according to the level signal of the level gauge. A transfer pump is also provided between the flash evaporator and the secondary heat exchanger, and the transfer pump is also communicatively connected to the level gauge.

5. The exhaust gas reuse system according to claim 3, characterized in that, Also includes: A steam generator is connected to the second steam inlet of the gas tank; The first pressure sensor is communicatively connected to the steam generator and is used to measure the gas pressure at the steam outlet of the flash evaporator. The steam generator produces saturated steam and delivers it to the gas tank; the steam generator shuts down after the pressure value measured by the first pressure sensor reaches a preset value and is maintained for a period of time exceeding a preset time.

6. The exhaust gas reuse system according to claim 3, characterized in that, Also includes: A plate heat exchanger, wherein the hot water inlet of the plate heat exchanger is connected to the hot water outlet of the secondary heat exchanger, and the hot water outlet of the plate heat exchanger is connected to the hot water inlet of the flash evaporator, so that the flash evaporator and the secondary heat exchanger are connected through the plate heat exchanger; The plate heat exchanger also has a circulating water inlet and a circulating water outlet. The plate heat exchanger uses circulating water to exchange heat in order to regulate the temperature of the hot water entering the flash evaporation device.

7. The exhaust gas reuse system according to claim 6, characterized in that, Also includes: A temperature sensor is used to measure the temperature of the hot water outlet pipeline of the plate heat exchanger. The second regulating valve is communicatively connected to the temperature sensor and is used to control the flow rate of the hot water inlet pipe of the plate heat exchanger based on the temperature signal from the temperature sensor.

8. The exhaust gas reuse system according to claim 1, characterized in that, Also includes: The second pressure sensor is used to measure the pressure of the air bag; A third regulating valve is communicatively connected to the second pressure sensor and is installed in the connecting pipeline between the air tank and the heat exchange device. The third regulating valve controls the pressure of the air tank within the range of 1.5~3.0 barg according to the pressure signal provided by the second pressure sensor.

9. The exhaust gas reuse system according to any one of claims 2 to 8, characterized in that, The temperature of the exhaust gas received at the exhaust gas inlet of the primary heat exchanger is 900~950℃; and / or The temperature of the exhaust gas received at the exhaust gas inlet of the secondary heat exchanger is 500~600℃; and / or The temperature of the exhaust gas discharged from the tail gas outlet of the secondary heat exchanger is 150~200℃; and / or Both the primary and secondary heat exchangers are vertical shell-and-tube heat exchangers, and the vertical shell-and-tube heat exchangers have fixed tube sheets and / or removable tube sheets; and / or The exhaust gas reuse system further includes an exhaust gas environmental treatment device, and the exhaust gas outlet of the secondary heat exchanger is connected to the exhaust gas environmental treatment device; and / or The incinerator uses air for combustion and natural gas as a supplementary fuel.

10. A porous carbon preparation system, characterized in that, include: Porous carbon preparation apparatus; The exhaust gas reuse system according to any one of claims 1 to 9, wherein the exhaust gas reuse system is connected to the porous carbon preparation device.

11. A method for reusing exhaust gas from porous carbon preparation, characterized in that, Includes the following steps: The exhaust gas emitted from the incineration of the porous carbon preparation; The heat from the exhaust gas after incineration is used to convert saturated steam into superheated steam. The obtained superheated steam is at least partially returned to the porous carbon preparation apparatus for the preparation of porous carbon.

12. The method for reusing exhaust gas from porous carbon preparation according to claim 11, characterized in that, The step of converting saturated steam into superheated steam using the heat from the incineration exhaust gas includes: The exhaust gas is passed through a primary heat exchanger, and the heat exchanged by the exhaust gas in the primary heat exchanger is used to prepare superheated steam. The exhaust gas discharged from the primary heat exchanger is passed through the secondary heat exchanger, and hot water is prepared by using the heat exchanged between the exhaust gas and the secondary heat exchanger. The prepared hot water is at least partially converted into saturated steam by flash evaporation; The superheated steam is prepared using the obtained saturated steam.

13. The method for reusing exhaust gas from porous carbon preparation according to claim 12, characterized in that, Prior to the step of flash evaporating at least part of the prepared hot water to prepare saturated steam, the method further includes: Saturated steam is prepared using a steam generator; Saturated steam is fed to a primary heat exchanger, where the heat exchanged between the exhaust gas and the primary heat exchanger is used to prepare superheated steam. After the step of preparing saturated steam from the prepared hot water at least partially by flash evaporation, the method further includes: Obtain the pressure value of the saturated steam prepared by flash evaporation; Once the measured pressure value reaches the preset value and is maintained for more than the preset time, the steam generator is turned off.

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