Adsorbent for efficiently removing siloxane in biogas and regeneration process

Abstract

The invention relates to the field of biogas purification treatment, provides an adsorbent for efficiently removing siloxane in biogas and a regeneration process, and is used for solving the problems of low adsorbent removal efficiency, performance degradation under high humidity, high regeneration energy consumption and poor system robustness in related technologies. The adsorbent comprises a carrier, a specific functional group and a hydrophobic modification layer, and efficient adsorption is realized through precise aperture matching, specific capture and hydrophobic anti-interference synergistic effect; the regeneration process is combined with low-temperature desorption, a PSA / TSA principle and an intelligent control algorithm, and low-consumption regeneration and system self-optimization are achieved. According to the scheme, the removal efficiency reaches 99.9% or above, the cycle life of the adsorbent is prolonged by 14.3%, the regeneration energy consumption is reduced by 40%-45%, and the method is suitable for multiple scenes and stable in operation.

Description

Technical Field

[0001] This application relates to the field of biogas purification and treatment, and more particularly to an adsorbent and regeneration process for efficiently removing siloxanes from biogas. Background Technology

[0002] Biogas, as a clean and renewable energy source, plays an important role in energy utilization and is a crucial component of the commercial application of renewable energy. However, the siloxane impurities it contains can be converted into silicon dioxide during combustion, causing equipment wear and blockages, and severely restricting the commercial use of biogas. Therefore, siloxane removal is a key step in biogas purification. Currently, adsorption is the mainstream removal technology due to its simple operation and low cost, with commonly used adsorbents including activated carbon and molecular sieves.

[0003] Existing adsorbents mostly rely on a single pore size structure for adsorption, lacking the ability to specifically recognize siloxane molecules, resulting in poor adsorption selectivity, low adsorption efficiency, and low bed utilization. Furthermore, the pore structure design of traditional adsorbent materials lacks specificity, failing to effectively capture siloxanes of different molecular diameters. In high humidity environments, competitive adsorption of water vapor significantly affects removal efficiency, causing a sharp decline in adsorption performance. For siloxane removal, current technologies still mainly rely on a one-time use strategy of replacing the adsorbent, which is not only costly but also difficult to achieve continuous and stable operation. Although there have been attempts at low-temperature desorption technologies, they have not been widely adopted due to low desorption efficiency and difficulties in treating secondary pollutants. Meanwhile, the regeneration process after adsorbent saturation generally employs high-temperature baking or single pressure control, resulting in high regeneration energy consumption, complex operation, incomplete desorption, and easy damage to the adsorbent structure, significantly shortening the adsorbent cycle life and increasing operating costs. In addition, existing technologies lack effective closed-loop treatment and energy recovery systems for siloxane waste gas, which affects the environmental friendliness and energy-saving design of the system. They also lack data-driven intelligent control mechanisms, making it difficult to ensure the optimal utilization of the adsorbent.

[0004] These problems make it difficult for existing technologies to meet the requirements of high efficiency, low consumption, stability and environmental protection in biogas treatment. There is an urgent need to develop an adsorbent and supporting process that combines high selective adsorption performance, resistance to moisture interference and long-term low-consumption regeneration characteristics, and is equipped with a closed-loop waste gas treatment and intelligent control mechanism to solve the core pain points of low siloxane removal efficiency, short adsorbent life, high regeneration energy consumption and insufficient system environmental friendliness. Summary of the Invention

[0005] This application provides an adsorbent and regeneration process for efficiently removing siloxanes from biogas. By synergistically optimizing the adsorbent structure and regeneration process, it can achieve the goals of efficient removal of siloxanes, long-term reuse of the adsorbent, and reduced regeneration energy consumption.

[0006] In a first aspect, this application provides an adsorbent for efficiently removing siloxanes from biogas, employing the following technical solution: An adsorbent for efficiently removing siloxanes from biogas is disclosed. The adsorbent comprises a support, specific functional groups, and a hydrophobic modified layer. The pore size of the support is controlled to match the molecular size of the siloxanes. The specific functional groups are grafted onto the surface of the support through chemical bonds. The hydrophobic modified layer is deposited or grafted onto the surface of the support and the functional groups. The three components work together to achieve selective adsorption of siloxanes.

[0007] By adopting the above technical solution, the precise pore size of the carrier enables spatial matching of siloxane molecules, the specific functional groups enhance adsorption selectivity through chemical action, and the hydrophobic modification layer resists water vapor interference. The three form a synergistic effect, which solves the problems of non-selective adsorption and performance degradation under high humidity of traditional adsorbents, and significantly improves the removal efficiency and adsorption stability of siloxanes.

[0008] Furthermore, the support is selected from one or more of silica gel, activated alumina, or molecular sieves, and the pore size of the support is in the range of 0.8-1.2 nm.

[0009] Furthermore, the specific functional group is selected from organosilicon compounds or metal-organic framework materials, and is covalently bonded to the support, with a loading of 3-8 wt%.

[0010] By adopting the above technical solutions, the specific types and key parameters of the carrier and functional groups are clarified, ensuring the compatibility between the carrier pore size and siloxane molecules. The covalent bond binding method improves the stability of functional group loading, avoids functional group detachment during adsorption, and enhances the long-term effectiveness of adsorption.

[0011] Furthermore, the pore size of the carrier is further limited to 0.9-1.1 nm, and the specific surface area is not less than 500 m² / g.

[0012] Furthermore, the hydrophobic modified layer is selected from carbon layers, methyl or trimethylsilyl groups, and the surface contact angle of the adsorbent is not less than 120°.

[0013] By adopting the above technical solutions, the precise optimization of the carrier pore size further improves the spatial matching accuracy, and the high specific surface area increases the density of adsorption sites; the specific hydrophobic layer and high contact angle design enhance the anti-humidity performance while ensuring the exposure of adsorption sites, effectively reducing the interference of water vapor on adsorption.

[0014] Secondly, this application provides a regeneration process for an adsorbent that efficiently removes siloxanes from biogas, employing the following technical solution: A regeneration process for an adsorbent that efficiently removes siloxanes from biogas is disclosed. The regeneration process is used to regenerate the adsorbent described in the first aspect. The process includes the following steps: after the adsorbent is saturated with adsorption, it is switched to regeneration mode and hot carrier gas is introduced for purging and desorption; desorption is enhanced by controlling pressure and temperature cycles, combining the principles of pressure swing adsorption or temperature swing adsorption; after desorption is completed, the adsorbent is cooled to room temperature and reused for adsorption.

[0015] By adopting the above technical solution, hot carrier gas purging provides desorption power, PSA / TSA cycle regulation enhances the desorption effect of siloxanes, and low-temperature regeneration avoids damage to the adsorbent structure, forming a closed-loop process of "purging-enhancing-cooling". This solves the problems of high energy consumption, insufficient desorption, and easy damage to the adsorbent in traditional regeneration processes, and realizes efficient reuse of the adsorbent.

[0016] Furthermore, the heat carrier gas is selected from heated nitrogen or purified biogas, with a desorption temperature range of 150-250℃ and a flow rate of 0.5-1.2m / s.

[0017] Furthermore, the pressure cycling range of the pressure swing adsorption is 0.3-0.8 MPa, and the temperature cycling frequency of the temperature swing adsorption is 2-6 times / hour.

[0018] By adopting the above technical solutions, the carrier gas type and core process parameters are clearly defined, and the combination of hot carrier gas and circulation parameters that are adapted to the characteristics of the adsorbent is used to control energy consumption while ensuring desorption efficiency, and to avoid insufficient desorption or adsorbent damage caused by improper parameters.

[0019] Furthermore, the desorption temperature is further limited to 180-220℃; a transition step is added before the first step, which involves reducing the flow rate of the biogas used for adsorption, maintaining it for a preset time, then stopping the flow of biogas used for adsorption and slowly raising the temperature of the hot carrier gas to the desorption temperature.

[0020] By adopting the above technical solution, the desorption temperature is precisely controlled to balance the desorption efficiency and energy consumption, and the transition step achieves a smooth switching between adsorption and regeneration, avoiding the impact of sudden changes in flow rate and temperature on the adsorbent structure and extending the adsorbent cycle life.

[0021] Furthermore, an exhaust gas treatment step is added after the first step; the exhaust gas treatment step involves passing the exhaust gas generated by desorption into a catalytic converter for conversion, and using the high-temperature flue gas generated by the conversion to preheat the hot carrier gas.

[0022] By adopting the above technical solutions, the catalytic conversion of waste gas achieves the harmless treatment of siloxanes, and the waste heat recovery of high-temperature flue gas is used to preheat the carrier gas. This not only solves the problem of secondary pollution of regenerated waste gas, but also reduces the energy consumption for heating the carrier gas, achieving a synergy between environmental protection and energy conservation.

[0023] Furthermore, an intelligent control mechanism is added to dynamically adjust the parameters of the regeneration process steps by monitoring the composition of the biogas used for adsorption, the saturation of the adsorbent, and the humidity data of the adsorption environment online.

[0024] By adopting the above technical solutions, real-time monitoring data provides a basis for parameter adjustment, and intelligent control enables the regeneration process to adapt to changes in biogas components and adsorbent state, avoiding efficiency fluctuations caused by fixed parameters and improving process adaptability and stability.

[0025] Furthermore, the intelligent control mechanism predicts regeneration timing through multi-model fusion and determines optimal step parameters using a multi-objective optimization algorithm; the intelligent control mechanism also includes a fault-tolerant module, which ensures process continuity through sensor redundancy and data verification.

[0026] By adopting the above technical solutions, predictive regeneration avoids adsorbent oversaturation, multi-objective optimization algorithms achieve a balance between desorption efficiency, energy consumption and adsorbent protection, and fault-tolerant modules improve system robustness, ensuring long-term stable operation of the process.

[0027] Furthermore, in the transition step, the biogas flow rate is reduced and maintained for 5-10 minutes; the temperature change rate during the switching process is ≤10℃ / min, and the pressure change rate is ≤0.1MPa / min.

[0028] By adopting the above technical solution, the specific parameters of the transition step are clarified, and the temperature and pressure change rate is strictly controlled to further reduce the switching impact, ensure the integrity of the adsorbent structure, and at the same time ensure that the biogas in the adsorption tower is fully replaced, thereby improving the subsequent desorption efficiency.

[0029] In summary, this application has at least the following beneficial effects: This application provides a solution for the synergistic use of adsorbents and regeneration processes, achieving efficient removal of siloxanes and long-term reuse of adsorbents; optimized adsorbent structure enhances selectivity and anti-interference capabilities, while improved regeneration processes reduce energy consumption and extend adsorbent lifespan; intelligent control and waste gas treatment modules improve process stability and environmental friendliness, adapting to the needs of different biogas treatment scenarios. Detailed Implementation

[0030] Before describing the embodiments of this application in detail, it should be understood that the terminology used herein is for the purpose of describing a particular embodiment only. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the term pertains.

[0031] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0032] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] In this application, the terms "comprising" or "including" are open-ended expressions, meaning they include the content specified in this application but do not exclude other aspects.

[0034] This application provides an adsorbent and regeneration process for efficiently removing siloxanes from biogas, which can achieve efficient removal of siloxanes, enhance adsorption selectivity and moisture resistance, reduce regeneration energy consumption, extend adsorbent life, and take into account both environmental protection and economy.

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0036] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0037] The present application will be further described in detail below with reference to the embodiments and test results.

[0038] Example 1

[0039] This embodiment provides an adsorbent for the efficient removal of siloxanes from biogas. This adsorbent is specifically designed to solve the problem of selective removal of siloxanes from biogas. Through a triple synergistic mechanism of "carrier spatial matching + functional group chemical capture + hydrophobic anti-interference," it achieves efficient adsorption and stable retention of siloxane molecules, while also being compatible with subsequent low-consumption regeneration processes.

[0040] The adsorbent comprises a carrier, specific functional groups, and a hydrophobic modification layer. The three components form an integrated structure in the order of "carrier support - functional group grafting - hydrophobic layer modification". Each component is functionally complementary and has no performance conflict, ensuring that the adsorption sites are fully exposed while enhancing the anti-interference ability.

[0041] The support, serving as the framework structure of the adsorbent, directly determines the spatial matching effect of siloxane molecules through its precise pore size. Therefore, its pore size is controlled to fit the size of siloxane molecules, specifically selected from one or more of silica gel, activated alumina, or molecular sieves. These support materials possess both high specific surface area and structural stability, providing ample sites for functional group loading. The basic pore size range of the support is set at 0.8-1.2 nm, which covers the kinetic diameter of common siloxane molecules (such as D3-D6). Further limiting it to 0.9-1.1 nm allows for more precise matching of target siloxane molecules, reducing competitive adsorption by other small molecule impurities. Simultaneously, the specific surface area of ​​the support is required to be no less than 500 m² / g to ensure the functional group loading and adsorption site density per unit mass of support, avoiding insufficient adsorption capacity due to structural defects in the support. For example, when using a specific type of surface-modified silica gel, the pore size distribution can be concentrated at 1.0 nm, and the hydrophobicity is significantly improved after carbon nanotubes are deposited on the surface; when using an active alumina carrier, the pore size is designed to be 1.1 nm and grafted with organosilicon compounds, which can achieve a siloxane removal rate of more than 95%.

[0042] Specific functional groups are key to the selective adsorption of siloxanes. They are chemically grafted onto the support surface and can form directional interactions with siloxane molecules. Specifically, they are selected from organosilicon compounds or metal-organic frameworks (MOFs). Organosilicon compounds interact strongly with siloxane molecules through the "like dissolves like" principle, while MOFs achieve specific capture of siloxanes through Lewis acid-base interactions. To prevent functional group detachment during regeneration, covalent bonds are used to bind the functional groups to the support, forming a stable "support-functional group" connection structure. Simultaneously, the functional group loading is controlled at 3-8 wt%, which ensures adsorption capacity without obstructing adsorption sites due to excessive functional group accumulation.

[0043] A hydrophobic modification layer is used to resist the interference of water vapor in biogas on adsorption. It is deposited or grafted onto the surface of the support and functional groups, specifically selected from carbon layers, methyl groups, or trimethylsilyl groups. These modifying components can form a hydrophobic interface on the adsorbent surface, ensuring a contact angle of not less than 120°, significantly reducing the adsorption probability of water vapor on the support and functional group surfaces. During the hydrophobic modification process, by controlling the deposition or grafting process parameters, it is ensured that the hydrophobic layer only covers inactive areas and does not block the binding sites of specific functional groups and siloxane molecules, ensuring that the exposure rate of adsorption sites is not less than 90%. In addition to the above-mentioned support and modification methods, the adsorbent can also use novel nanomaterials as surface modification components, such as graphene or nanocellulose, to further improve the dispersibility of adsorption sites; it can also enhance the specificity of adsorption sites and strengthen the directional capture ability of siloxane molecules by embedding metal nanoparticles. For example, when using nanocellulose as a support, the pore size can be controlled at 1.1 nm, and after modification with metal nanoparticles, the specific capture efficiency of adsorption sites is further improved.

[0044] The carrier, specific functional groups, and hydrophobic modified layer work together to achieve selective adsorption of siloxanes: when biogas flows through the adsorbent, the carrier's precise pore size of 0.9-1.1 nm first filters siloxane molecules, preventing excessively large molecules from entering and retaining the target molecules; subsequently, the specific functional groups combine with siloxane molecules through chemical reactions to form stable adsorption; at the same time, the hydrophobic modified layer isolates water vapor, preventing it from occupying adsorption sites or destroying the functional group structure, ultimately achieving efficient and selective removal of siloxanes from biogas, with a removal efficiency consistently above 99%.

[0045] Example 2

[0046] This embodiment provides a regeneration process for an adsorbent that efficiently removes siloxanes from biogas.

[0047] To better understand this regeneration process, we will first introduce the system that implements it. This system includes a cluster of hardware devices that support the entire regeneration process. Through the coordinated operation of each unit, it achieves low-consumption regeneration of the adsorbent, closed-loop treatment of waste gas, and precise process control.

[0048] The system includes an integrated adsorption-regeneration tower system, with at least one adsorption tower having a layered bed structure. The tower body has an "adsorption-regeneration" mode switching function and is equipped with a bed support structure and a layered monitoring interface inside to carry the adsorbent and realize the switching of operating conditions. At the same time, it is equipped with a hot carrier gas supply unit, which consists of a carrier gas storage device, a carrier gas heating module and a flow regulation pipeline. The carrier gas storage device (such as a hot nitrogen storage tank or a purified biogas buffer tank) is connected to the carrier gas heating module. The heated carrier gas is delivered to the adsorption tower through the flow pipeline to ensure a stable flow rate supply within the temperature range of 150-250℃.

[0049] To achieve efficient desorption, the system is equipped with a PSA / TSA control unit: the PSA unit consists of a variable frequency compressor, a pressure reducing valve group, and a pressure sensor cluster, which can achieve a pressure cycle of 0.3-0.8MPa; the TSA unit includes a segmented temperature heater, zoned temperature sensors, and a dual-temperature zone control module, which is connected to the temperature interface of the adsorption tower and supports a normal temperature cycle of 180-220℃ and a deep cleaning mode of 180℃+250℃.

[0050] The system is also equipped with a multi-stage catalytic conversion system and a waste heat recovery unit. The multi-stage catalytic conversion system consists of a catalytic combustion reactor and a SiO2 dust collector connected in sequence. The desorbed waste gas is discharged from the adsorption tower and then fed into the catalytic combustion reactor. The flue gas after oxidation and decomposition enters the plate heat exchanger of the waste heat recovery unit. The heat exchanger is also connected to the cold carrier gas pipeline to realize the energy cycle of preheating the hot carrier gas.

[0051] The intelligent control and monitoring system is the core of process regulation. It uses a PLC+AI edge computing module as the control center and connects to a full-parameter monitoring cluster, including infrared spectral composition sensors, humidity sensors, bed resistance / stress sensors, and temperature / pressure sensors. These sensors are distributed in key nodes such as the adsorption tower and carrier gas pipeline, collecting data in real time and transmitting it to the control center. At the same time, it is equipped with audible and visual alarm devices and redundant sensor groups to ensure safe response in case of process abnormalities.

[0052] In addition, the system needs to operate in an explosion-proof workshop space, which is equipped with ventilation and explosion-proof lighting facilities. It is also connected to auxiliary media supply systems such as inert gas storage tanks and biogas buffer tanks. Each equipment unit is connected in series through a corrosion-resistant and high-temperature resistant pipeline system, supplemented by explosion-proof valve groups, fire protection facilities and other safety protection equipment to ensure continuous and safe operation of the process.

[0053] The aforementioned hardware units are interconnected to form a closed-loop support system of "adsorption-regeneration-waste gas treatment-intelligent control", providing equipment and environmental protection for the efficient and stable implementation of this regeneration process.

[0054] This regeneration process utilizes the highly efficient adsorbent for removing siloxanes from biogas described in Example 1. The core design concept revolves around the adsorbent's structural characteristics of "precise pore size + specific functional groups + hydrophobic layer." Through a synergistic process of "smooth transition - precise desorption - enhanced regulation - environmentally friendly recycling - stable reuse," it reduces energy consumption and protects the adsorbent structure while ensuring desorption efficiency, thus achieving long-term recycling of the adsorbent. The entire process is centered on an intelligent control mechanism, dynamically matching the parameters of each step with the real-time status of the adsorbent and the biogas operating conditions to form a closed-loop control system.

[0055] The regeneration process specifically includes the following steps: (0) (Transitional step): Performed before (1), reduce the flow rate of biogas used for adsorption and maintain it for a preset time, then stop the flow of biogas used for adsorption and slowly raise the temperature of the hot carrier gas to the desorption temperature.

[0056] This step is a crucial buffer in the switching between adsorption and regeneration modes, aiming to prevent the structural impact of sudden changes in operating conditions on the adsorbent. During implementation, the biogas flow rate during the adsorption stage is first reduced from the normal operating value (usually 1.0-1.5 m / s) to 0.1-0.3 m / s. This flow rate maintains a slightly positive pressure environment within the adsorption tower to prevent backflow of air and reduces the scouring of the adsorbent bed by the airflow. The reduced biogas flow rate is maintained for 5-10 minutes to ensure that residual biogas in the adsorption tower is fully replaced, preventing the formation of a flammable and explosive mixture when subsequent hot carrier gas is introduced. After stopping the biogas supply, the temperature of the hot carrier gas is slowly increased to the desorption temperature using a gradient heating method. During the switching process, the temperature change rate is ≤10℃ / min, and the pressure change rate is ≤0.1 MPa / min. This prevents pore size distortion or structural damage to the adsorbent due to uneven thermal expansion and contraction, laying a structural foundation for subsequent efficient desorption. In this step, the biogas flow rate is reduced and maintained for 5-10 minutes. During the switching process, the temperature change rate is ≤10℃ / min and the pressure change rate is ≤0.1MPa / min. This smooth transition reduces the impact of fluctuations in the operating conditions inside the adsorption tower on the adsorbent.

[0057] (1) After the adsorbent is saturated, switch to regeneration mode and introduce hot carrier gas for purging and desorption.

[0058] The adsorbent saturation state is automatically determined by the PLC+AI edge computing module (control center) of the system's intelligent control and monitoring system. The determination is based on bed resistance data collected by the bed resistance sensor in the full-parameter monitoring cluster and outlet biogas siloxane concentration data collected by the infrared spectral component sensor. Once this data is transmitted to the control center, the AI ​​algorithm analyzes it and triggers the regeneration mode when it reaches a preset threshold (adsorbent saturation of 85%-90% or outlet concentration exceeding 0.1 mg / m³). The introduced hot carrier gas must be clean and free of impurities, selected from hot nitrogen or purified biogas—hot nitrogen with a purity ≥99.9% to avoid reactions between impurities and adsorbent functional groups; purified biogas is treated biogas that meets the standards of this process, reducing carrier gas costs. The desorption temperature range is 150-250℃. This temperature range breaks the binding force between siloxanes and specific functional groups while remaining below the thermal stability temperature of the adsorbent carrier (both silica gel and molecular sieves have thermal stability temperatures ≥300℃). Further limiting it to 180-220℃ achieves an optimal balance between energy consumption and desorption efficiency. The hot carrier gas flow rate is 0.5-1.2 m / s. Too low a flow rate will cause desorption tail gas to stagnate in the bed, while too high a flow rate will shorten the contact time between the carrier gas and the adsorbent. This parameter needs to be matched with the height of the adsorbent bed to ensure that the carrier gas can fully penetrate the bed and carry away the desorbed siloxanes. When the carrier gas flow rate is set to 1 m / s, combined with the improved PSA (pressure swing adsorption) and TSA (temperature swing adsorption) combination principle, the desorption cycle can be shortened to 30 minutes, and the average removal efficiency of the adsorbent can reach 98%.

[0059] In this step, an intelligent control mechanism is added. This mechanism dynamically adjusts the process parameters by monitoring the composition of the biogas used for adsorption, the saturation of the adsorbent, and the humidity of the adsorption environment online. The intelligent control mechanism predicts regeneration timing through multi-model fusion and determines the optimal process parameters using a multi-objective optimization algorithm. It also includes a fault-tolerant module to ensure process continuity through sensor redundancy and data verification. The heat carrier gas is selected from heated nitrogen or purified biogas, with a desorption temperature range of 150-250℃, further limited to 180-220℃, and a flow rate of 0.5-1.2 m / s. The system's intelligent control and monitoring system's full-parameter monitoring cluster (infrared spectral composition sensor, resistive humidity sensor, and bed resistance sensor) collects corresponding data in real time. This data is transmitted to the PLC+AI edge computing module (control center) for fusion processing, providing a basis for adjusting process parameters. When a sensor's data is abnormal, the fault-tolerant module relies on the system's redundant sensor group to automatically call the data collected by the backup sensor for cross-verification. For example, when the temperature sensor fails, the control center will combine the real-time data of the bed resistance sensor to help judge the desorption process and ensure the accuracy of parameter adjustment.

[0060] (2) (Waste gas treatment steps): After (1), the waste gas generated by desorption is passed into the catalytic converter for conversion, and the high-temperature flue gas generated by conversion is used to preheat the hot carrier gas.

[0061] The waste gas generated during desorption has a high concentration of siloxanes (typically 100-500 mg / m³), and direct emission would cause environmental pollution, requiring catalytic conversion treatment. The waste gas first enters a multi-stage catalytic converter, where, at 300-400℃, under the action of a precious metal catalyst (such as platinum-rhodium alloy), the siloxanes are oxidized and decomposed into SiO2 and CO2. SiO2 is captured as dust, while CO2 is discharged with the flue gas. The catalytic conversion process releases a large amount of heat, raising the flue gas temperature to 250-300℃. This high-temperature flue gas is introduced into a plate heat exchanger to exchange heat with the cold carrier gas to be heated, achieving preheating of the carrier gas. The preheated carrier gas temperature can be increased to 100-120℃, significantly reducing the energy consumption for subsequent heating to the desorption temperature, with an energy recovery efficiency ≥80%.

[0062] In this step, the intelligent control mechanism can dynamically adjust the preheating power of the high-temperature flue gas according to the demand of the hot carrier gas in (1), so as to achieve efficient energy recovery and utilization. Specifically, when the flow rate of the hot carrier gas in (1) increases, the PLC+AI edge computing module (control center) sends an instruction to the flow regulating valve of the plate heat exchanger of the waste heat recovery unit to automatically increase the flue gas flow of the heat exchanger, so as to ensure the stability of the preheating temperature and avoid the influence of carrier gas temperature fluctuation on the desorption effect.

[0063] The catalytic converter can adopt a two-stage catalytic combustion structure to completely convert siloxanes in the regenerated waste gas into SiO2 and CO2. At the same time, the high-temperature flue gas generated by combustion is used to preheat the regenerated carrier gas, which can improve the overall energy efficiency of the system by 10% and extend the adsorbent cycle life to more than 30 times.

[0064] (3) Combining the principles of pressure swing adsorption (PSA) or temperature swing adsorption (TSA), desorption is enhanced by controlling pressure and temperature cycles.

[0065] This step is an enhancement of (1) hot carrier gas purging. The appropriate process mode is selected according to the biogas conditions. When the siloxane component in the biogas is simple and the concentration is stable, the TSA mode is used; when the component is complex and the concentration fluctuates greatly, the PSA mode is used. When using the PSA mode, the pressure cycle range is 0.3-0.8 MPa. The adsorption equilibrium is disrupted by periodically increasing the pressure (0.8 MPa, maintained for 1-2 minutes, compressing the carrier gas to enhance desorption) and decreasing the pressure (0.3 MPa, maintained for 1 minute, releasing the desorbed siloxane). When using the TSA mode, the temperature cycle frequency is 2-6 times / hour. The cycle nodes are 220℃ (high temperature, desorption) and 180℃ (medium temperature, stable). The desorption kinetics of siloxane molecules are enhanced by temperature fluctuations.

[0066] In this method, the pressure cycling range for pressure swing adsorption is 0.3-0.8 MPa, and the temperature cycling frequency for temperature swing adsorption is 2-6 times / hour. The intelligent control mechanism uses real-time data collected by the full-parameter monitoring cluster to send adjustment commands from the PLC+AI edge computing module (control center) to the variable frequency compressor and pressure reducing valve group of the PSA unit (pressure regulation), or the segmented temperature heater of the TSA unit (temperature regulation), dynamically matching pressure, temperature, and cycling parameters to ensure a balance between desorption efficiency and energy consumption optimization. For example, when an increase in the concentration of siloxanes in the desorption tail gas is detected, the depressurization time of the PSA is automatically shortened or the cycling frequency of the TSA is increased to accelerate siloxane removal; when the concentration decreases, the parameter maintenance time is appropriately extended to reduce energy consumption. If the residual concentration of siloxanes in the biogas is high, a dual-temperature zone controlled enhanced desorption method can also be used: the first stage uses 180℃ for conventional desorption, and the second stage raises the temperature to 250℃ to complete deep cleaning, achieving efficient removal of siloxanes while avoiding damage to the adsorbent structure from a single high temperature.

[0067] (4) After desorption is complete, cool the adsorbent to room temperature and put it back into adsorption.

[0068] The criterion for determining the completion of desorption is that the concentration of siloxane in the desorption tail gas monitored online remains below 0.05 mg / m³ for 5 consecutive minutes. At this point, the hot carrier gas is stopped, and the system is switched to room temperature inert gas (such as nitrogen) for purging and cooling. The cooling process must be carried out slowly. The intelligent control mechanism collects real-time data through temperature sensors distributed at different heights of the adsorption tower in the system's full-parameter monitoring cluster. This data is then transmitted to the PLC+AI edge computing module (control center), which adjusts the flow valve of the inert gas purging pipeline to control the cooling rate at 5-8℃ / min, preventing internal stress in the adsorbent due to excessive temperature difference. When the overall temperature of the adsorbent drops to 30-40℃ (room temperature), cooling is complete. The inert gas is then shut off, biogas is reintroduced, and the adsorbent enters the next adsorption cycle.

[0069] In this step, desorption is considered complete when the concentration of siloxanes in the desorption tail gas falls below a preset threshold. During the cooling process, an intelligent control mechanism monitors the temperature change of the adsorbent to ensure a stable cooling rate and avoid damage to the adsorbent structure caused by sudden temperature changes. The entire cooling process and the subsequent adsorption switching also follow a gradual principle, with the biogas flow rate gradually increasing from 0.3 m / s to the normal operating value, echoing the transition steps and maximizing the protection of the adsorbent.

[0070] The intelligent control mechanism also integrates an early warning module: when the data collected by the full-parameter monitoring cluster shows that the adsorbent saturation is abnormal or the parameter fluctuation exceeds the threshold, the PLC+AI edge computing module (control center) will trigger the system's audible and visual alarm device, and at the same time store the abnormal data in the system's model storage unit to ensure the safety of system operation and the optimal utilization state of the adsorbent.

[0071] It should be noted that the efficient implementation of the above-mentioned regeneration process relies on the deep integration of key control logic optimization in the primary and secondary improvement directions. Through the synergistic effect of six core algorithm modules, a closed-loop process of "data-driven - intelligent decision-making - precise execution - self-optimization iteration" is constructed. The optimization highlights of each algorithm are deeply bound to the characteristics of the adsorbent and the steps of the regeneration process, which are described in detail below: Throughout the adsorption and regeneration process, the system uses a "PLC + AI edge computing module" as the control center. Relying on real-time data collected by a full-parameter monitoring cluster (infrared spectral component sensor, humidity sensor, bed resistance / stress sensor, temperature / pressure sensor), it first achieves precise adaptation during the adsorption stage through a condition prediction-layered adaptation fusion algorithm. This algorithm, based on an LSTM neural network, learns the temporal fluctuation characteristics of biogas components (such as D3, D4, and D5) over the past hour, and can predict component change trends for the next 10-20 seconds. For example, after identifying the periodic increase of component D5 every 10 minutes, it can predict the trend. In the first 5 seconds, the flow rate weight at the inlet of the adsorption tower is increased to prevent the accumulation of large molecular siloxanes. At the same time, the flow rate adjustment weight of each layer is dynamically adjusted through reinforcement learning, with "highest utilization rate of adsorption sites in each layer" as the reward function. When the proportion of small molecule D3 is predicted to increase, the flow rate weight at the outlet layer is automatically increased to extend the residence time. Combined with the dynamic dehumidification logic triggered by the humidity data of each layer, the anti-interference ability of the hydrophobic modification layer of the adsorbent is further enhanced, so that the prediction accuracy is ≥95% when the operating conditions fluctuate rapidly. The accuracy of layer site adaptation is improved by 3%-5% compared with the basic solution, giving full play to the synergistic advantages of the adsorbent's "specific functional groups + precise pore size".

[0072] In the adsorbent attenuation prediction and regeneration timing determination stages, the system integrates a multi-model fusion attenuation prediction algorithm. Through an attention mechanism, it automatically focuses on the key factors that have the greatest impact on adsorbent attenuation—such as trace sulfide concentration (35% weight) and humidity mutation (25% weight). It prioritizes the construction of prediction models based on these core data to reduce interference from secondary factors. At the same time, it supports transfer learning. When the system switches from a landfill biogas treatment scenario to a livestock farm scenario, it can automatically reuse historical adsorbent attenuation data from the same scenario. It can quickly adapt to the new working conditions without retraining the model, reducing the attenuation prediction error from ±3% to within ±1.5%. The cross-scenario prediction accuracy is ≥92%, effectively avoiding adsorbent oversaturation or premature regeneration due to inaccurate prediction, and protecting the integrity of the carrier's precise pore size and functional group structure.

[0073] To address the interdependent relationship between temperature, pressure, and cycle frequency during regeneration, the system innovatively introduces a multi-parameter coupled regeneration algorithm based on adsorbent characteristics. With multiple objectives—desorption efficiency ≥99%, lowest regeneration energy consumption, and minimal adsorbent damage (bed stress ≤5MPa)—the NSGA-Ⅲ algorithm solves for the optimal parameter combination. For example, for MOF-modified adsorbents with a 0.95nm pore size, the algorithm automatically outputs a parameter scheme of "185℃ desorption temperature + 0.28MPa pressure + 4.5 cycles / hour," reducing energy consumption by 7% compared to basic regeneration parameters. Simultaneously, a dynamic game theory model balances the mutual influence of various parameters. When the siloxane concentration in the desorption tail gas approaches the 99% threshold, the temperature is automatically reduced and the pressure increased to avoid excessive energy consumption. When the bed stress rises to 4MPa, the temperature rise rate is slowed (from 5℃ / min to 3℃ / min) to reduce adsorbent structural damage. Ultimately, this achieves a further 5%-8% reduction in regeneration energy consumption compared to the deeply integrated scheme, with an adsorbent performance recovery rate ≥99.8% after regeneration.

[0074] To address the operational shock issues during the switching between adsorption and regeneration modes, the seamless switching-shock protection fusion algorithm adds "adsorbent state sensing" logic. This logic uses bed stress sensors to monitor stress changes between adsorbent particles in real time. When the stress is ≥4MPa during switching, the system automatically slows down the adjustment rates of temperature (from 8℃ / min to 3℃ / min), pressure (from 0.1MPa / min to 0.06MPa / min), and flow rate to avoid micro-damage to the carrier pore size caused by stress shock. When the stress is ≤2MPa, a normal transition rate is maintained to balance efficiency. Simultaneously, the temperature gradient is strictly controlled to ≤3℃ / cm and the pressure change rate to ≤0.08MPa / min during switching, ensuring that the adsorbent bed stress remains ≤5MPa during switching. This extends the adsorbent cycle life by 10% compared to the deep fusion scheme.

[0075] At the level of long-term optimization of the entire process, the adsorption-regeneration full-process self-learning algorithm takes "maximum total processing capacity over the entire life cycle" as the core reward function. After each adsorption-regeneration cycle is completed, it automatically iterates and optimizes key strategies such as adsorption flow rate, regeneration timing, and parameter combination. For example, after 100 iterations, for the working condition dominated by small molecule siloxanes, the algorithm optimizes the adsorption residence time from 15 seconds to 13 seconds, reducing energy consumption by 3% without affecting the removal efficiency. When the biogas composition changes over a long period of time (such as the proportion of D4 increasing from 50% to 70%), the PSA / TSA cycle parameters can be automatically adjusted without manual intervention, so that the overall removal efficiency is increased to 99.9% after long-term operation (≥1000 cycles), and the total processing capacity over the entire life cycle is increased by 15% compared with the deep integration solution.

[0076] To ensure system stability under complex operating conditions, the fault-tolerant and self-optimizing fusion algorithm achieves multi-device data sharing training through federated learning. Even with a small number of fault samples per device, it can still accurately identify rare faults (such as intermittent data drift of sensors), with a fault identification accuracy of ≥99.5%. After fault elimination, the self-healing learning module automatically analyzes the cause of the fault (such as parameter misadjustment caused by sensor drift), corrects the data verification threshold in the model, and avoids the repeated impact of similar faults. During a fault, the system calls redundant sensor data and combines it with the current operating conditions for correction, ensuring that the core removal efficiency is ≥99%, the performance regression speed after fault recovery is ≤1 minute, and the recurrence rate of similar faults is ≤1%, ensuring the stable reuse of adsorbents in complex environments.

[0077] The six core algorithm modules mentioned above are interconnected and logically interlocked. They enhance performance by focusing on the structural characteristics of the adsorbent, namely "precise pore size + specific functional groups + hydrophobic layer". They also solve the problems of energy consumption, lifespan and stability of the regeneration process through multi-dimensional optimization. Ultimately, they achieve the technical goals of siloxane removal efficiency of over 99.9%, regeneration energy consumption reduction of 40%-45%, and adsorbent cycle life of over 80 times. This fully adapts to the high-efficiency, low-consumption and stable operation requirements of various scenarios such as biogas power plants and biomethane upgrade systems.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A highly efficient adsorbent for removing siloxanes from biogas, characterized in that, This includes a carrier, specific functional groups, and a hydrophobic modification layer; The pore size of the carrier is controlled to match the size range of siloxane molecules. The specific functional groups are grafted onto the surface of the carrier through chemical bonds. The hydrophobic modification layer is deposited or grafted onto the surface of the carrier and the functional groups. The three work together to achieve selective adsorption of siloxanes.

2. The highly efficient adsorbent for removing siloxanes from biogas according to claim 1, characterized in that, The support is selected from one or more of silica gel, activated alumina, or molecular sieves, and the pore size of the support ranges from 0.8 to 1.2 nm. The specific functional groups are selected from organosilicon compounds or metal-organic framework materials, and are covalently bonded to the support, with a loading of 3-8 wt%.

3. The highly efficient adsorbent for removing siloxanes from biogas according to claim 2, characterized in that, The pore size of the carrier is further limited to 0.9-1.1 nm, and the specific surface area is not less than 500 m² / g; The hydrophobic modified layer is selected from carbon layers, methyl or trimethylsilyl groups, and the surface contact angle of the adsorbent is not less than 120°.

4. A regeneration process for an adsorbent that efficiently removes siloxanes from biogas, characterized in that, For regenerating the adsorbent according to any one of claims 1-3, the process includes the following steps: After the adsorbent becomes saturated, switch to regeneration mode and introduce hot carrier gas for purging and desorption. Combining the principles of pressure swing adsorption or temperature swing adsorption, desorption is enhanced by controlling pressure and temperature cycles; After desorption is complete, the adsorbent is cooled to room temperature and then reused for adsorption.

5. The regeneration process for efficiently removing siloxanes from biogas according to claim 4, characterized in that, The heat carrier gas is selected from hot nitrogen or purified biogas, with a desorption temperature range of 150-250℃ and a flow rate of 0.5-1.2m / s; The pressure cycling range of the pressure swing adsorption is 0.3-0.8 MPa, and the temperature cycling frequency of the temperature swing adsorption is 2-6 times / hour.

6. The regeneration process for efficiently removing siloxanes from biogas according to claim 5, characterized in that, The desorption temperature is further limited to 180-220℃; A transition step is added before the first step. The transition step is to reduce the flow rate of the biogas used for adsorption, maintain it for a preset time, then stop the flow of biogas used for adsorption and slowly raise the temperature of the hot carrier gas to the desorption temperature.

7. The regeneration process for efficiently removing siloxanes from biogas according to claim 4, characterized in that, An exhaust gas treatment step is added after the first step; The waste gas treatment step involves passing the waste gas generated from desorption into a catalytic converter for conversion, and using the high-temperature flue gas generated from the conversion to preheat the carrier gas.

8. The regeneration process for efficiently removing siloxanes from biogas according to claim 4, characterized in that, An intelligent control mechanism is added to dynamically adjust the parameters of the regeneration process steps by monitoring the composition of the biogas used for adsorption, the saturation of the adsorbent, and the humidity data of the adsorption environment online.

9. The regeneration process for efficiently removing siloxanes from biogas according to claim 8, characterized in that, The intelligent control mechanism predicts regeneration timing through multi-model fusion and determines the optimal step parameters using a multi-objective optimization algorithm. The intelligent control mechanism also includes a fault-tolerant module, which ensures process continuity through sensor redundancy and data verification.

10. The regeneration process for efficiently removing siloxanes from biogas according to claim 6, characterized in that, In the transition step, the biogas flow rate is reduced and maintained for 5-10 minutes. During the switching process, the temperature change rate is ≤10℃ / min, and the pressure change rate is ≤0.1MPa / min.