Biogas purification and heating method for boiler combustion

Abstract

The invention discloses a biogas purification and heating method for boiler combustion, and relates to the technical field of biogas heating. The method comprises the following specific steps: biogas collection and preliminary treatment: biogas is collected from a biogas generation source, and passed through a primary filtering device with a filter screen with a specific mesh number to remove dust and solid residue impurities. The invention can significantly improve the purification efficiency of biogas by introducing a magnetic field-assisted purification process. Under the action of the magnetic field, magnetic impurity particles in the biogas will move and aggregate in a directional manner, thereby being easier to remove by physical separation means. At the same time, the magnetic field can also promote the activity and reaction rate of substances involved in the purification reaction, effectively accelerate the decomposition and conversion of impurities, and enable the biogas to be more thoroughly purified. The quality of the biogas after magnetic field-assisted purification is significantly improved, and the impurity content is greatly reduced, so that it can be more fully burned in the subsequent combustion and heating links, releasing more heat, thereby improving the combustion efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of biogas heating, in particular to a biogas purification heating method for boiler combustion. Background Art

[0002] In the field of heating technology, with the increasing global attention to the use of clean energy and the increasing demand for energy conservation and emission reduction, biogas, as a renewable biomass energy source, has received widespread attention for its application potential. Biogas is mainly produced by the fermentation of organic waste under anaerobic conditions. It is a methane-rich combustible gas suitable for boiler combustion and heating. However, various impurities such as dust, moisture, hydrogen sulfide and carbon dioxide are often mixed into biogas during its production and collection process. These impurities will not only reduce the combustion efficiency of biogas, but may also cause corrosion and blockage to the combustion equipment, affecting the stable operation of the system. Therefore, efficient purification of biogas to improve its combustion efficiency and quality has become a key issue that needs to be urgently solved in the field of biogas heating.

[0003] Traditional biogas purification methods mainly include physical filtration, chemical absorption and biological treatment, but these methods have obvious limitations in treatment effect and adaptability. Although physical filtration can remove large particles of impurities, it is not effective for small particles and soluble impurities. Although chemical absorption and biological treatment can remove some harmful components, the treatment process is complicated and the cost is high, and there is a lack of effective removal methods for magnetic impurities in biogas. In addition, traditional methods often lack the ability to dynamically adjust according to biogas operating conditions, resulting in unstable purification effects and difficulty in improving combustion efficiency. Especially in the application of magnetic field-assisted purification technology, traditional technology has failed to fully tap the strengthening effect of the magnetic field on the biogas purification process, and has failed to achieve real-time matching of magnetic field parameters with biogas operating conditions, thereby limiting the improvement of biogas purification efficiency.

[0004] In view of the above problems, it is necessary to optimize the existing biogas purification and heating methods. By introducing the magnetic field assisted purification process and combining it with adaptive magnetic field regulation technology, efficient purification and stable heating of biogas can be achieved. Therefore, it is of great significance to develop a biogas purification and heating method for boiler combustion that can comprehensively realize the above characteristics. Summary of the invention

[0005] The purpose of the present invention is to make up for the shortcomings of the prior art and provide a method for purifying and heating biogas for boiler combustion. It can achieve efficient removal of biogas impurities and fine control of the combustion process by introducing a magnetic field-assisted purification process and combining it with adaptive magnetic field regulation technology. It can also monitor biogas parameters in real time and intelligently adjust the magnetic field strength and direction to dynamically optimize the purification process and ensure that the biogas quality is steadily improved. At the same time, combined with air conditioning and premixing steps, subsequent purification steps, and tail gas treatment and emission steps, it achieves full-chain optimization from biogas collection to combustion heating, significantly improves heating efficiency, and reduces pollutant emissions.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a biogas purification and heating method for boiler combustion, the method comprising the following specific steps:

[0007] Biogas collection and preliminary treatment: Collect biogas from the biogas source, pass it through a primary filtration device with a filter of a specific mesh size to remove dust and solid residue impurities, and discharge it into a buffer tank equipped with a pressure sensor and a safety valve. The pressure sensor is used for real-time monitoring and the safety valve is used to maintain the pressure in the tank stable;

[0008] Real-time monitoring of biogas parameters: Install high-precision gas flow sensors, component analyzers and magnetic impurity content detection equipment on the biogas transmission pipeline after preliminary treatment to measure the biogas flow, composition and magnetic impurity content in real time. Use the biogas component comprehensive determination algorithm based on multi-sensor fusion to calculate the comprehensive proportion of each key component, and transmit the detection data to the intelligent control system in real time;

[0009] Magnetic field assisted purification: Magnetic field generators are arranged around biogas transmission pipelines and purification reaction vessels to create a magnetic field environment, so that magnetic impurities and weak magnetic aggregates in biogas can be directed to move and aggregate in the magnetic field. Impurities are removed through the set filter and centrifugal device. At the same time, magnetic catalysts are added to enhance their activity by using the magnetic field to promote the decomposition and conversion of impurities. Based on the magnetic impurity content and reaction process data, the intensity, direction and range of action of the magnetic field generator are dynamically adjusted through algorithms to optimize the magnetic field assisted purification process.

[0010] Air conditioning and premixing: Based on the biogas flow and composition data after magnetic field-assisted purification, the optimal air introduction amount and the mixing ratio with biogas are calculated according to the dynamic correction algorithm of the optimal air introduction amount based on combustion dynamics and energy balance. By adjusting the opening of the air flow regulating valve, the air introduction amount is accurately controlled, and the air and biogas are transported to the premixing device so that they are fully and evenly premixed according to the optimal mixing ratio to form premixed gas;

[0011] Subsequent purification treatment: The premixed gas is passed through a purification device filled with adsorbents and catalysts in layers, and the purification effect is estimated using the impurity purification efficiency estimation formula. The catalyst is fully utilized by controlling the temperature and pressure conditions in the device to remove impurities in the premixed gas;

[0012] Combustion heating: The purified premixed gas is transported to the boiler burner. A temperature sensor and a flame monitor are installed on the burner to monitor the combustion temperature and flame status in real time. The data is transmitted to the intelligent control system. With the help of the burner power adaptive adjustment algorithm based on real-time heat flow feedback, the burner power is dynamically adjusted according to the real-time heat flow and heating demand changes, and the heat generated by the combustion is transferred to the medium in the boiler, and external heating is realized through the circulation system;

[0013] Exhaust treatment and emission: Collect exhaust gas generated by combustion and introduce it into the exhaust treatment device. Use a dust collector to remove particulate matter, and use lime-gypsum desulfurization and denitrification technology to reduce the content of sulfur dioxide and nitrogen oxide pollutants. Use the exhaust gas emission determination algorithm based on multi-pollutant coordinated control to determine whether the exhaust gas meets the standards. The exhaust gas that meets the standards is discharged into the atmosphere.

[0014] Furthermore, in the step of real-time monitoring of biogas parameters, a comprehensive biogas component determination algorithm based on multi-sensor fusion is used to calculate the comprehensive proportion of each key component, and the algorithm formula is:

[0015] in, Indicates the comprehensive proportion of each key component in biogas, is the number of key components monitored, It is The weight coefficient of each component in the combustion and purification process, It is The sensor measurement signal value corresponding to the component, For the Sensor error correction coefficient corresponding to the components; It is The weight coefficient of each component in the combustion and purification process, It is The sensor measurement signal value corresponding to the component, This is for The sensor error correction coefficient corresponding to the component.

[0016] Furthermore, in the magnetic field-assisted purification step, a magnetic catalyst is added, and the magnetic field is used to enhance its activity to promote the decomposition and conversion of impurities. Specifically, as the biogas is continuously introduced into the purification reaction container, the impurity molecules contained therein move toward the magnetic catalyst under the influence of the magnetic field force and the concentration difference factor under the magnetic field environment, and are more easily adsorbed onto the active sites of the catalyst. At the active sites, due to the enhancing effect of the magnetic field on the activity of the catalyst, the chemical bonds in the impurity molecules become easier to break, and their chemical structure is destroyed to form active intermediates. Under the specific chemical environment around the active sites and the continuous influence of the magnetic field, they rapidly react chemically with the oxygen component from the biogas or other additives participating in the reaction, and are converted into harmless small molecules through atomic rearrangement and chemical bond formation processes.

[0017] Furthermore, in the magnetic field assisted purification step, the intensity, direction and range of action of the magnetic field generator are dynamically adjusted by an algorithm to optimize the magnetic field assisted purification process. The algorithm formula is:

[0018] in, is the optimal magnetic field strength obtained by adaptive adjustment, is the number of different types of magnetic impurities in biogas that can be affected by the magnetic field, It is The charge of the magnetic impurities, It is The magnetic permeability of the magnetic impurities, It is The average radius of the magnetic impurities, is the target impurity removal rate at the current moment, is the initial impurity removal rate, It is The average distance that a magnetic impurity is disturbed by other impurities in a magnetic field, is the number of purification reaction vessels within the magnetic field action area, is the cosine value of the angle between the magnetic field direction and the impurity directional movement direction, It is the matching coefficient between the magnetic field range and the impurity distribution area.

[0019] Furthermore, in the air conditioning and premixing step, the required optimal air introduction amount and the mixing ratio with biogas are calculated according to the dynamic correction algorithm of the optimal air introduction amount based on combustion dynamics and energy balance, and the calculation formula is:

[0020] in, is the corrected optimal air introduction amount, is the initial air intake calculated based on the ideal stoichiometric ratio. is the fluctuation of the methane content in biogas relative to the standard reference value, is the combustion efficiency coefficient of the burner under the current working conditions, is the temperature correction factor, is the pressure correction factor, is the energy balance reference coefficient, It is the dynamic adjustment factor of the excess air coefficient.

[0021] Furthermore, in the subsequent purification step, the purification effect is estimated using an impurity purification efficiency estimation formula, and the calculation formula is:

[0022] in, Indicates the impurity purification efficiency, is the concentration of the target impurity before the premixed gas enters the purification device, is the concentration of target impurities after the premixed gas passes through the purification device. If the value does not meet the expected requirements, the adsorbent and catalyst should be checked or replaced, or the operating parameters of the purification device should be adjusted.

[0023] Furthermore, in the combustion heating step, the burner power is dynamically adjusted according to the real-time heat flow and heating demand changes by means of a burner power adaptive adjustment algorithm based on real-time heat flow feedback, and the calculation formula is:

[0024] in, is the burner power after adaptive adjustment, is the initial setting power of the burner, is the difference between the real-time heat flow and the target heat flow, is the heat transfer efficiency correction factor, is the energy loss compensation factor, is the number of different media or areas involved in heat exchange, It is Real-time flow of a medium or area, It is The specific heat capacity of a medium or region, It is The inlet and outlet temperature difference of a medium or region, It is the dynamic adjustment factor of heating demand.

[0025] Furthermore, in the exhaust gas treatment and emission step, an exhaust gas emission standard determination algorithm based on multi-pollutant coordinated control is used to determine whether the exhaust gas meets the standard, and the algorithm formula is:

[0026] in, Indicates the exhaust gas emission standard judgment value. is the number of exhaust pollutant types that need to be monitored and controlled. It is The actual emission concentration of the pollutants after tail gas treatment. It is The national emission standard concentration limit values ​​of the pollutants.

[0027] Furthermore, in the exhaust gas treatment and discharge step, lime-gypsum desulfurization and denitrification technology is used to reduce the content of sulfur dioxide and nitrogen oxide pollutants. Specifically, the exhaust gas enters the desulfurization and denitrification device, and in the desulfurization and denitrification device, an absorption liquid containing lime is sprayed from the top of the tower, and the calcium hydroxide solution is fully in contact with the exhaust gas in the form of mist. The sulfur dioxide in the exhaust gas reacts chemically with the calcium hydroxide to generate calcium sulfite precipitate. In the slurry pool at the bottom of the absorption tower, the absorption liquid containing calcium sulfite is oxidized to calcium sulfate under the action of the blown air. For the nitrogen oxides in the exhaust gas, in the alkaline environment in the absorption tower, the nitrogen oxides will react with water to generate nitric acid and nitrous acid. The generated nitric acid and nitrous acid will further react with calcium hydroxide to generate calcium nitrate and calcium nitrite substances, thereby achieving the removal of nitrogen oxides and reducing their content in the exhaust gas.

[0028] Compared with the prior art, the biogas purification and heating method for boiler combustion has the following beneficial effects:

[0029] 1. The present invention can significantly improve the purification efficiency of biogas by introducing a magnetic field-assisted purification process. Under the action of the magnetic field, the magnetic impurity particles in the biogas will move and aggregate in a directional manner, making it easier to remove them by physical separation means. At the same time, the magnetic field can also promote the activity and reaction rate of the substances involved in the purification reaction, effectively accelerate the decomposition and transformation of impurities, and make the biogas more thoroughly purified. The quality of the biogas after magnetic field-assisted purification is significantly improved, and the impurity content is greatly reduced, so that it can burn more fully in the subsequent combustion and heating links, releasing more heat and improving the combustion efficiency.

[0030] 2. The present invention realizes dynamic optimization of magnetic field parameters through adaptive magnetic field regulation technology. According to the actual biogas working conditions, the strength, direction and range of the magnetic field are automatically adjusted through intelligent algorithms, ensuring that the magnetic field can continue to play the best auxiliary purification role under different working conditions. It not only improves the reliability and durability of the heating system, but also helps to extend the service life of the combustion equipment, reduces maintenance costs, and meets the requirements of efficient energy utilization and environmental protection.

[0031] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 The present invention is a process operation diagram of a biogas purification heating method for boiler combustion;

[0034] Figure 2 The present invention is a flow chart of a biogas purification and heating method for boiler combustion. DETAILED DESCRIPTION

[0035] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0036] Embodiment 1

[0037] In a large-scale breeding farm, a large amount of biogas is produced through anaerobic fermentation of breeding waste. The multiple biogas generating pools in the breeding farm collect the produced biogas through a pipeline network and transport it to the primary filtration device. The filtration device uses an 80-mesh filter screen, which can effectively intercept large particles of impurities such as dust and fecal residues with a diameter greater than 0.18 mm. The biogas after preliminary filtration enters a buffer tank with a volume of 10 cubic meters. The buffer tank is equipped with a high-precision pressure sensor to monitor the pressure in real time and feed back the signal to the control system. At the same time, the safety valve is set in the pressure range of 0.7-1.1MPa. When the pressure in the tank exceeds this range, it will automatically adjust to ensure that the biogas is supplied to the subsequent links at a stable pressure.

[0038] A high-precision gas flow sensor model [ABC-100] is installed on the main delivery pipeline after the buffer tank. Its measurement accuracy can reach ±0.3%, which can accurately measure the biogas flow in real time. The component analyzer uses the [IR-Analyzer200] model based on the infrared spectroscopy principle. It analyzes the biogas composition every 8 seconds and combines it with a comprehensive biogas composition judgment algorithm based on multi-sensor fusion. Calculate the proportion of each component, where Indicates the comprehensive proportion of each key component in biogas, is the number of key components monitored, It is The weight coefficient of each component in the combustion and purification process, It is The sensor measurement signal value corresponding to the component, For the Sensor error correction coefficient corresponding to the components; It is The weight coefficient of each component in the combustion and purification process, It is The sensor measurement signal value corresponding to the component, This is for The sensor error correction coefficient corresponding to each component. In addition, it is equipped with [MagSense-50] magnetic impurity content detection equipment, which detects the magnetic impurities in biogas in real time based on the magnetic induction principle. All detection data are sent to the intelligent control system in the farm in real time via wireless transmission.

[0039] An electromagnetic coil-type magnetic field generator is arranged along the biogas transmission pipeline and the subsequent purification reaction container (with a volume of 5 cubic meters, made of stainless steel, and an internal structure design that is conducive to uniform distribution and full reaction of the gas), which can generate a magnetic field with an intensity range of 0.15-0.8 Tesla. When the biogas enters the magnetic field area, the trace magnetic impurities such as iron and nickel contained therein and the weakly magnetic agglomerates formed by chemical reactions move and aggregate in a directional manner under the action of the magnetic field. A filter with an aperture of 0.04mm is set at a specific position of the pipeline to intercept and remove the aggregated impurities. A magnetic catalyst (filling amount of 80kg) with magnetic iron oxide as a carrier and loaded with specific metal oxide active ingredients is put into the purification reaction container to catalyze the decomposition and conversion of impurities such as hydrogen sulfide. The adaptive magnetic field adjustment module receives real-time data such as the content of magnetic impurities in the biogas and the change in the concentration of hydrogen sulfide in the purification reaction container, and optimizes the algorithm based on the correlation between the adaptive magnetic field strength and the impurity removal effect. Dynamically adjust the magnetic field generator parameters, where is the optimal magnetic field strength obtained by adaptive adjustment, is the number of different types of magnetic impurities in biogas that can be affected by the magnetic field, It is The charge of the magnetic impurities, It is The magnetic permeability of the magnetic impurities, It is The average radius of the magnetic impurities, is the target impurity removal rate at the current moment, is the initial impurity removal rate, It is The average distance that a magnetic impurity is disturbed by other impurities in a magnetic field, is the number of purification reaction vessels within the magnetic field action area, is the cosine value of the angle between the magnetic field direction and the impurity directional movement direction, It is the matching coefficient between the magnetic field range and the impurity distribution area.

[0040] The intelligent control system dynamically corrects the algorithm for the optimal amount of air introduced based on combustion dynamics and energy balance according to the received biogas flow and composition data after magnetic field-assisted purification. , accurately calculate the optimal amount of air required for the current biogas combustion and the mixing ratio with biogas, among which, is the corrected optimal air introduction amount, is the initial air intake calculated based on the ideal stoichiometric ratio. is the fluctuation of the methane content in biogas relative to the standard reference value, is the combustion efficiency coefficient of the burner under the current working conditions, is the temperature correction factor, is the pressure correction factor, is the energy balance reference coefficient, It is a dynamic adjustment factor of the excess air coefficient. By adjusting the opening of the electric air flow control valve (model [AirValve-300], the opening control accuracy can reach 1%), the amount of air introduced is accurately controlled, so that air and biogas enter the premixing device with a spiral turbulence structure inside. In the device, the two are fully and evenly premixed to form a premixed gas, ensuring that subsequent combustion is more efficient and stable.

[0041] The premixed gas is passed into the purification device, which is filled with 120kg of activated alumina adsorbent (used to absorb moisture to reduce the moisture content to below 0.8%) and 60kg of catalyst specially used to catalyze the reaction of hydrogen sulfide and oxygen into elemental sulfur (the best catalytic effect is achieved under the condition of temperature control at 220-280℃). The impurity purification efficiency estimation formula is used. Real-time estimation of purification effect, including: Indicates the impurity purification efficiency, is the concentration of the target impurity before the premixed gas enters the purification device, is the concentration of target impurities after the premixed gas passes through the purification device. If the value does not meet the expected requirements, the adsorbent and catalyst should be checked or replaced, or the operating parameters of the purification device should be adjusted. According to the estimated results, the gas flow rate, temperature and other parameters should be adjusted in time to ensure that impurities such as hydrogen sulfide in the premixed gas are effectively removed and the gas quality is improved.

[0042] The purified premixed gas is transported to a swirl burner with a rated power of 800kW through a pipeline. The special swirl structure inside the burner can make the premixed gas form a stable flame for full combustion. A temperature sensor model [TempSensor-600] and a flame monitor based on the principle of ultraviolet detection are installed at the key parts of the burner to monitor the flame temperature and state in real time, and feed the data back to the intelligent control system. The intelligent control system is based on the burner power adaptive adjustment algorithm based on real-time heat flow feedback. , dynamically adjust the burner power according to the difference between the real-time heat flow and the target heat flow and the change in heating demand, among which, is the burner power after adaptive adjustment, is the initial setting power of the burner, is the difference between the real-time heat flow and the target heat flow, is the heat transfer efficiency correction factor, is the energy loss compensation factor, is the number of different media or areas involved in heat exchange, It is Real-time flow of a medium or area, It is The specific heat capacity of a medium or region, It is The inlet and outlet temperature difference of a medium or region, It is a dynamic adjustment factor for heating demand. The heat generated by combustion is transferred to the hot water circulation system in the farm through the heat exchanger, providing stable hot water for the breeding house for heating, cleaning and disinfection and other purposes.

[0043] The exhaust gas generated by combustion is collected through pipelines and enters the exhaust gas treatment device. It first passes through a bag filter (the bag is made of polyester fiber and has a filtration accuracy of 3μm) to remove most of the particulate matter, and then enters the integrated desulfurization and denitrification device using the lime-gypsum method for pollutant treatment. In the desulfurization and denitrification device, by spraying calcium hydroxide absorption liquid from the top of the tower, the sulfur dioxide in the exhaust gas reacts with calcium hydroxide to form calcium sulfite. The calcium sulfite is oxidized to calcium sulfate through aeration in the bottom slurry pool and finally forms gypsum crystals. At the same time, the nitrogen oxides in the exhaust gas also react with calcium hydroxide and the like in an alkaline environment and under oxidizing conditions and are partially removed. The various pollutant indicators of the treated exhaust gas are monitored in real time by detection equipment (such as particulate matter detector, gas analyzer, etc.) installed at the outlet of the exhaust treatment device, and an exhaust emission compliance judgment algorithm based on multi-pollutant coordinated control is used. Determine whether the standard is met, among which, Indicates the exhaust gas emission standard judgment value. is the number of exhaust pollutant types that need to be monitored and controlled. It is The actual emission concentration of the pollutants after tail gas treatment. It is The national emission standard concentration limit values ​​of various pollutants are met. When the content of each pollutant in the exhaust gas meets the corresponding emission standards, the exhaust gas is judged to be up to standard and discharged into the atmosphere through a chimney with a height of 25m and a diameter of 0.8m, ensuring that the entire heating process meets environmental protection requirements, reduces pollution to the atmospheric environment around the farm, realizes clean utilization of biogas and stable heating, and meets the heat needs of winter heating, cleaning and disinfection in the farm.

[0044] Embodiment 2

[0045] In a certain rural area, in order to realize the centralized heating of multiple villages, a biogas centralized heating station was built to collect the biogas produced by the biogas digesters of multiple farmers in the surrounding area as energy. The biogas produced by the biogas digesters scattered in the farmers' homes was collected through an underground pipeline network and transported to a centralized primary filtration device. The filter mesh of the device is 120 mesh, which can effectively intercept various large particles with a diameter greater than 0.12mm, such as straw residues, soil particles, etc. The biogas after primary filtration enters a large buffer tank with a total volume of 20 cubic meters. A high-precision pressure sensor and a safety valve are installed in the buffer tank. The pressure sensor monitors the pressure in the tank in real time. The pressure range set by the safety valve is 0.6-1.0MPa, so as to ensure the stability of the biogas supply pressure and meet the subsequent large-scale processing and heating needs.

[0046] A high-precision gas flow sensor (model [FlowPro-200], with a measurement accuracy of up to ±0.2%) is installed on the main transmission pipeline at the rear end of the buffer tank to measure the biogas flow in real time and continuously, and transmit the data to the intelligent control system of the heating station. A component analyzer based on laser spectral analysis technology (model [LaserAnal-500]) is used to analyze the biogas composition in real time, focusing on the detection of key components such as methane, carbon dioxide, and hydrogen sulfide. The data is updated every 6 seconds, and the proportion of each component is accurately calculated through the built-in biogas composition comprehensive judgment algorithm based on multi-sensor fusion. At the same time, the [MagCheck-80] magnetic impurity content detection equipment is used to monitor the magnetic impurity content in the biogas in real time, and the data is also transmitted to the intelligent control system in real time (the system is built on the [SmartCtrl-Plus] platform, with powerful data processing and multi-task coordination capabilities).

[0047] A magnetic field generator (using electromagnetic induction, which can generate a magnetic field with an intensity range of 0.2-1.0 Tesla) is arranged around the main biogas transportation pipeline and subsequent multiple parallel purification reaction containers (each container has a volume of 8 cubic meters, is made of carbon steel lining anti-corrosion material, and is equipped with a gas guide plate inside to ensure uniform gas flow) to construct a magnetic field environment. When the biogas flows through the magnetic field area, the magnetic impurities therein move and gather in a direction under the action of the magnetic field, and are intercepted and removed by a filter with an aperture of 0.03mm set at the corresponding position of the pipeline. A magnetic composite catalyst (with a total loading volume of 150kg, composed of a magnetic carrier loaded with a variety of active ingredients, and having a good catalytic decomposition ability for impurities such as hydrogen sulfide and organic sulfur) is added into the purification reaction container. With the help of the enhancement effect of the magnetic field on the activity of the catalyst, the impurities are decomposed and converted. The data such as the content of magnetic impurities in the biogas and the changes in the concentration of key impurities in each purification reaction container are received in real time through the adaptive magnetic field adjustment technology. The intensity, direction and range of action of the magnetic field generator are dynamically adjusted using the adaptive magnetic field intensity and impurity removal effect correlation optimization algorithm to ensure that the magnetic field-assisted purification effect is always in the best state and that the impurities in the biogas are efficiently removed.

[0048] The intelligent control system uses the data on biogas flow and composition after magnetic field-assisted purification and a dynamic correction algorithm for the optimal amount of air introduced based on combustion dynamics and energy balance to accurately calculate the required optimal amount of air introduced and the mixing ratio with biogas. By adjusting the opening of a high-precision electric air flow control valve (model [AirRegulator-500], with an opening adjustment accuracy of up to 0.5%), the amount of air introduced is precisely controlled, and the air and biogas are transported together to a large premixing device (with a multi-stage turbulent mixing structure inside to ensure that the gas is fully and evenly mixed) for premixing to form a uniform premixed gas, thus making full preparations for subsequent efficient combustion.

[0049] The premixed gas is passed into the purification device, and the inside of the purification device is filled with adsorbents such as activated alumina (filling amount is 200kg), molecular sieve (filling amount is 100kg) for adsorbing moisture and other small molecular impurities according to functional layers, as well as specific desulfurization and denitrification catalysts (filling amount is 100kg, which can efficiently catalyze the reaction of hydrogen sulfide and oxygen to generate elemental sulfur in the temperature range of 200-300℃, and have a certain reduction and conversion effect on nitrogen oxides). The impurity purification efficiency estimation formula is used to evaluate the purification effect in real time. According to the evaluation results, the operating parameters such as temperature and gas flow rate in the purification device are adjusted to ensure that the impurity content of the premixed gas is significantly reduced after purification, and the quality is greatly improved, so as to meet the strict requirements of subsequent combustion heating on gas purity.

[0050] The purified premixed gas is transported through pipelines to multiple parallel high-power boiler burners (each burner has a rated power of 1200kW and adopts a new swirl combustion technology to ensure stable combustion of the premixed gas) for combustion. High-precision temperature sensors (model [TempSense-800]) and flame monitors (using the visible light and infrared composite detection principle to accurately monitor the flame state) are installed at key locations of each burner to monitor the combustion temperature and flame state in real time and feed the data back to the intelligent control system. The intelligent control system uses a burner power adaptive adjustment algorithm based on real-time heat flow feedback to dynamically adjust the power of each burner according to the difference between the real-time heat flow and the heating target and the actual demand changes in each heating area, ensuring that the entire heating station can stably and efficiently provide sufficient heat for rural residential buildings, village-run schools and other places to meet winter heating and other heating needs.

[0051] The exhaust gas generated by each burner is collected and introduced into the exhaust gas treatment device through a pipeline. It first passes through a bag dust collector (the bag is made of high-temperature-resistant and wear-resistant aramid material with a filtration accuracy of 2μm) to remove most of the particulate matter, and then enters the integrated desulfurization and denitrification device using the lime-gypsum method for deep treatment. In the desulfurization and denitrification device, by reasonably configuring the spray volume of the calcium hydroxide absorption liquid, aeration intensity and other parameters, the sulfur dioxide in the exhaust gas is fully reacted with calcium hydroxide to form calcium sulfite, and the calcium sulfite is further oxidized to calcium sulfate and crystallized to form gypsum. At the same time, the nitrogen oxides in the exhaust gas react with calcium hydroxide in an alkaline environment and an oxidizing atmosphere to achieve a certain degree of removal. The treated exhaust gas passes through the device Various pollutant detection equipment (such as high-precision particle counters, chemiluminescence nitrogen oxide analyzers, ultraviolet fluorescence sulfur dioxide analyzers, etc.) installed at the outlet of the exhaust treatment device monitor various pollutant indicators in real time, and use the exhaust emission determination algorithm based on multi-pollutant coordinated control to determine whether the national rural heating exhaust gas emission standards are met (such as particulate matter content less than 10mg / m³, sulfur dioxide content less than 50mg / m³, nitrogen oxide content less than 100mg / m³). The exhaust gas that meets the standards is discharged into the atmosphere through a chimney with a height of 35m and a diameter of 1.2m, ensuring that the entire heating process meets environmental protection requirements and reduces pollution to the rural atmospheric environment.

[0052] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A biogas purification and heating method for boiler combustion, characterized in that: The method comprises the following specific steps: Biogas collection and preliminary treatment: Collect biogas from the biogas source, pass it through a primary filtration device with a filter of a specific mesh size to remove dust and solid residue impurities, and discharge it into a buffer tank equipped with a pressure sensor and a safety valve. The pressure sensor is used for real-time monitoring and the safety valve is used to maintain the pressure in the tank stable; Real-time monitoring of biogas parameters: Install high-precision gas flow sensors, component analyzers and magnetic impurity content detection equipment on the biogas transmission pipeline after preliminary treatment to measure the biogas flow, composition and magnetic impurity content in real time. Use the biogas component comprehensive determination algorithm based on multi-sensor fusion to calculate the comprehensive proportion of each key component, and transmit the detection data to the intelligent control system in real time; Magnetic field assisted purification: Magnetic field generators are arranged around biogas transmission pipelines and purification reaction vessels to create a magnetic field environment, so that magnetic impurities and weak magnetic aggregates in biogas can be directed to move and aggregate in the magnetic field. Impurities are removed through the set filter and centrifugal device. At the same time, magnetic catalysts are added to enhance their activity by using the magnetic field to promote the decomposition and conversion of impurities. Based on the magnetic impurity content and reaction process data, the intensity, direction and range of action of the magnetic field generator are dynamically adjusted through algorithms to optimize the magnetic field assisted purification process. Air conditioning and premixing: Based on the biogas flow and composition data after magnetic field-assisted purification, the optimal air introduction amount and the mixing ratio with biogas are calculated according to the dynamic correction algorithm of the optimal air introduction amount based on combustion dynamics and energy balance. By adjusting the opening of the air flow regulating valve, the air introduction amount is accurately controlled, and the air and biogas are transported to the premixing device so that they are fully and evenly premixed according to the optimal mixing ratio to form premixed gas; Subsequent purification treatment: The premixed gas is passed through a purification device filled with adsorbents and catalysts in layers, and the purification effect is estimated using the impurity purification efficiency estimation formula. The catalyst is fully utilized by controlling the temperature and pressure conditions in the device to remove impurities in the premixed gas; Combustion heating: The purified premixed gas is transported to the boiler burner. A temperature sensor and a flame monitor are installed on the burner to monitor the combustion temperature and flame status in real time. The data is transmitted to the intelligent control system. With the help of the burner power adaptive adjustment algorithm based on real-time heat flow feedback, the burner power is dynamically adjusted according to the real-time heat flow and heating demand changes, and the heat generated by the combustion is transferred to the medium in the boiler, and external heating is realized through the circulation system; Exhaust treatment and emission: Collect exhaust gas generated by combustion and introduce it into the exhaust treatment device. Use a dust collector to remove particulate matter, and use lime-gypsum desulfurization and denitrification technology to reduce the content of sulfur dioxide and nitrogen oxide pollutants. Use the exhaust gas emission determination algorithm based on multi-pollutant coordinated control to determine whether the exhaust gas meets the standards. The exhaust gas that meets the standards is discharged into the atmosphere.

2. A biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the biogas parameter real-time monitoring step, the comprehensive proportion of each key component is calculated using a comprehensive biogas component determination algorithm based on multi-sensor fusion, and the algorithm formula is: in, Indicates the comprehensive proportion of each key component in biogas, is the number of key components monitored, It is The weight coefficient of each component in the combustion and purification process, It is The sensor measurement signal value corresponding to the component, For the Sensor error correction coefficient corresponding to the components; It is The weight coefficient of each component in the combustion and purification process, It is The sensor measurement signal value corresponding to the component, This is for The sensor error correction coefficient corresponding to the component.

3. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the magnetic field assisted purification step, a magnetic catalyst is added, and the specific method of using the magnetic field to enhance its activity to promote the decomposition and conversion of impurities is as follows: biogas is continuously introduced into the purification reaction container, and the impurity molecules contained therein are driven by the magnetic field force and the concentration difference factor under the magnetic field environment, and move toward the direction of the magnetic catalyst and are adsorbed onto the active sites of the catalyst. At the active sites, due to the enhancement effect of the magnetic field on the activity of the catalyst, the chemical bonds in the impurity molecules become easier to break, and their chemical structure is destroyed to form active intermediates. Under the specific chemical environment around the active sites and the continuous influence of the magnetic field, they quickly react chemically with the oxygen component from the biogas or other additives participating in the reaction, and are converted into harmless small molecules through atomic rearrangement and chemical bond formation processes.

4. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the magnetic field assisted purification step, the intensity, direction and range of action of the magnetic field generator are dynamically adjusted by an algorithm to optimize the magnetic field assisted purification process. The algorithm formula is: in, is the optimal magnetic field strength obtained by adaptive adjustment, is the number of different types of magnetic impurities in biogas that can be affected by the magnetic field, It is The charge of the magnetic impurities, It is The magnetic permeability of the magnetic impurities, It is The average radius of the magnetic impurities, is the target impurity removal rate at the current moment, is the initial impurity removal rate, It is The average distance that a magnetic impurity is disturbed by other impurities in a magnetic field, is the number of purification reaction vessels within the magnetic field action area, is the cosine value of the angle between the magnetic field direction and the impurity directional movement direction, It is the matching coefficient between the magnetic field range and the impurity distribution area.

5. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the air conditioning and premixing step, the required optimal air introduction amount and the mixing ratio with biogas are calculated according to the dynamic correction algorithm of the optimal air introduction amount based on combustion dynamics and energy balance. The calculation formula is: in, is the corrected optimal air introduction amount, is the initial air intake calculated based on the ideal stoichiometric ratio. is the fluctuation of the methane content in biogas relative to the standard reference value, is the combustion efficiency coefficient of the burner under the current working conditions, is the temperature correction factor, is the pressure correction factor, is the energy balance reference coefficient, It is the dynamic adjustment factor of the excess air coefficient.

6. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the subsequent purification step, the purification effect is estimated using the impurity purification efficiency estimation formula, and the calculation formula is: in, Indicates the impurity purification efficiency, is the concentration of the target impurity before the premixed gas enters the purification device, is the concentration of target impurities after the premixed gas passes through the purification device. If the value does not meet the expected requirements, the adsorbent and catalyst should be checked or replaced, or the operating parameters of the purification device should be adjusted.

7. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the combustion heating step, the burner power is dynamically adjusted according to the real-time heat flow and heating demand changes by means of a burner power adaptive adjustment algorithm based on real-time heat flow feedback. The calculation formula is: in, is the burner power after adaptive adjustment, is the initial setting power of the burner, is the difference between the real-time heat flow and the target heat flow, is the heat transfer efficiency correction factor, is the energy loss compensation factor, is the number of different media or areas involved in heat exchange, It is Real-time flow of a medium or area, It is The specific heat capacity of a medium or region, It is The inlet and outlet temperature difference of a medium or region, It is the dynamic adjustment factor of heating demand.

8. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the exhaust gas treatment and emission step, an exhaust gas emission standard determination algorithm based on multi-pollutant coordinated control is used to determine whether the exhaust gas meets the standard. The algorithm formula is: in, Indicates the exhaust emission standard judgment value. is the number of exhaust pollutant types that need to be monitored and controlled. It is The actual emission concentration of the pollutants after tail gas treatment. It is The national emission standard concentration limit values ​​of the pollutants.

9. The biogas purification and heating method for boiler combustion according to claim 1, characterized in that: In the exhaust gas treatment and emission step, the specific method of using lime-gypsum desulfurization and denitrification technology to reduce the content of sulfur dioxide and nitrogen oxide pollutants is as follows: the exhaust gas enters the desulfurization and denitrification device, and in the desulfurization and denitrification device, an absorption liquid containing lime is sprayed from the top of the tower, and the calcium hydroxide solution is fully in contact with the exhaust gas in the form of mist, and the sulfur dioxide in the exhaust gas reacts chemically with the calcium hydroxide to generate calcium sulfite precipitation. In the slurry pool at the bottom of the absorption tower, the absorption liquid containing calcium sulfite is oxidized to calcium sulfate under the action of the blown air. For nitrogen oxides in the exhaust gas, in the alkaline environment in the absorption tower, the nitrogen oxides will react with water to generate nitric acid and nitrous acid, and the generated nitric acid and nitrous acid will further react with calcium hydroxide to generate calcium nitrate and calcium nitrite substances, thereby achieving the removal of nitrogen oxides and reducing their content in the exhaust gas.

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