Flue gas waste heat recovery system and method based on novel vertical inverted-U-shaped heat pipe heat exchanger

Abstract

The invention discloses a flue gas waste heat recovery system and method based on a novel vertical inverted-U-shaped heat pipe heat exchanger, and relates to the technical field of energy recovery. The system comprises a bag-type dust collector, a molecular sieve adsorber, a gas separation membrane assembly, a vertical inverted U-shaped heat pipe heat exchanger, a turbine, a generator and an energy accumulator, wherein the bag-type dust collector, the molecular sieve adsorber, the gas separation membrane assembly, the vertical inverted U-shaped heat pipe heat exchanger and the turbine are connected in sequence; and the turbine is respectively connected with the generator and the energy accumulator. Through core equipment innovation, multi-technology cooperation and intelligent control, an efficient, stable and environment-friendly flue gas waste heat recovery system is constructed, and a breakthrough solution is provided for industrial energy conservation and emission reduction.

Description

Technical Field

[0001] This invention relates to the field of energy recovery technology, and more specifically to a flue gas waste heat recovery system and method based on a novel vertical inverted U-shaped heat pipe heat exchanger. Background Technology

[0002] In industrial production processes, various heating equipment (such as boilers and furnaces) generate large amounts of flue gas during operation, which contains abundant waste heat resources. However, traditional technologies face numerous problems in the recovery and utilization of flue gas waste heat. On the one hand, energy utilization efficiency is low; a large amount of heat and combustible materials carried by the flue gas are not effectively recovered, resulting in serious energy waste due to direct emissions. On the other hand, the recovery and utilization of low-grade flue gas waste heat faces significant challenges. Due to its low temperature and corrosive substances, the recovery process is complex and costly, and currently, the recovery of low-grade flue gas waste heat is almost non-existent. Furthermore, existing flue gas waste heat recovery power generation systems also have shortcomings in structural design and operational efficiency. Some systems fail to fully optimize the integration of heat exchangers and power generation units, resulting in low heat exchange efficiency and insufficient waste heat utilization. Moreover, these systems are structurally complex and have high maintenance costs. Common steam Rankine cycle systems are poorly adaptable to low-grade flue gas waste heat, making it difficult to achieve efficient waste heat recovery power generation. Furthermore, some specific flue gas waste heat recovery power generation and dust removal systems, such as AOD furnace flue gas waste heat recovery power generation and dust removal systems, still need improvement in terms of waste heat recovery efficiency, system integration, and flexibility in adapting to different operating conditions. Meanwhile, Stirling power generation systems utilizing medium- and low-temperature flue gas also have room for further improvement in terms of system structural compactness, heat exchange efficiency, and adaptability to different industrial scenarios.

[0003] In modern industrial applications, traditional heat exchange equipment such as shell-and-tube heat exchangers, plate heat exchangers, finned heat exchangers, and double-tube heat exchangers have been widely used. However, these devices generally suffer from problems such as complex structure, high energy consumption, low heat exchange efficiency, and insufficient energy utilization, making it difficult to meet the urgent needs of modern industry for efficient and energy-saving heat exchange equipment. Therefore, developing a new type of efficient heat exchange equipment has become an inevitable trend in the industry.

[0004] Patent CN202020487335.1 discloses an innovative U-shaped heat exchange tube device, whose design highlight lies in its unique corrugated structure. This structure can significantly expand the heat transfer area, thereby greatly improving the heat transfer rate and effectively solving the problem of low heat exchange efficiency in traditional heat exchange equipment. Compared with traditional heat exchange pipes, the U-shaped heat exchange tube also has many advantages: its disassembly process is simple and quick, and it has lower requirements for the operating conditions of the equipment, greatly reducing the maintenance cost and operation difficulty. More importantly, this device can significantly reduce energy consumption in practical applications, by up to 50% or more. This not only saves enterprises a lot of energy costs but also provides strong support for achieving energy conservation and emission reduction goals.

[0005] In view of the problems existing in current technologies for flue gas waste heat recovery and power generation, this invention proposes a flue gas waste heat recovery system and method based on a novel vertical inverted U-shaped heat pipe heat exchanger. This system and method aim to achieve efficient recovery and conversion of flue gas waste heat, thereby significantly improving energy utilization, reducing energy waste, and meeting increasingly stringent environmental protection requirements. Through innovative system design and optimized process flow, this invention provides an effective technical solution for energy conservation, emission reduction, and sustainable development in the industrial sector. Summary of the Invention

[0006] In view of this, the present invention provides a flue gas waste heat recovery system and method based on a novel vertical inverted U-shaped heat pipe heat exchanger. The system takes the novel vertical inverted U-shaped heat pipe heat exchanger as its core and has significant process features.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger includes:

[0009] Baghouse dust collectors, molecular sieve adsorbers, gas separation membrane modules, vertical inverted U-shaped heat pipe heat exchangers, turbines, generators, and accumulators;

[0010] The bag filter, molecular sieve adsorber, gas separation membrane assembly, vertical inverted U-shaped heat pipe heat exchanger, and turbine are connected in sequence.

[0011] The turbine is connected to the generator and the accumulator respectively.

[0012] Preferably, the above system further includes: a chimney and induced draft fans; the induced draft fans include a first induced draft fan, a second induced draft fan, a third induced draft fan, a fourth induced draft fan, and a fifth induced draft fan;

[0013] The first induced draft fan is disposed between the chimney and the bag filter; the second induced draft fan is disposed between the bag filter and the molecular sieve adsorber; the third induced draft fan is disposed between the molecular sieve adsorber and the gas separation membrane assembly; the fourth induced draft fan is disposed between the gas separation membrane assembly and the vertical inverted U-shaped heat pipe heat exchanger; and the fifth induced draft fan is disposed between the vertical inverted U-shaped heat pipe heat exchanger and the turbine.

[0014] The vertical inverted U-shaped heat pipe heat exchanger is also connected to the first induced draft fan.

[0015] Preferably, the above system also includes: a public power grid, a chemical distillation reactor, a domestic heating system, a steam condenser, a water storage tank, and a water pump;

[0016] The generator is connected to the public power grid;

[0017] The turbine is also connected to the chemical distillation reactor, the domestic heating system, and the steam condenser, respectively.

[0018] The steam condenser is connected in sequence to the water storage tank, the water pump, and the vertical inverted U-shaped heat pipe heat exchanger.

[0019] Preferably, the above system further includes: an integrated intelligent instrument module, a data integration control cabinet, and a computer; the data integration control cabinet and the computer are connected.

[0020] The integrated intelligent instrument module includes: a temperature indicating and control instrument, a pressure indicating and control instrument, a pressure indicating instrument, a dust concentration indicating instrument, a flow indicating instrument, and a liquid level indicating instrument;

[0021] Temperature and pressure indicators are connected to the following pipelines: the pipeline between the first induced draft fan and the bag filter, the pipeline between the bag filter and the second induced draft fan, the pipeline between the second induced draft fan and the molecular sieve adsorber, the pipeline between the molecular sieve adsorber and the third induced draft fan, the pipeline between the third induced draft fan and the gas separation membrane assembly, the pipeline between the gas separation membrane assembly and the fourth induced draft fan, the pipeline between the fourth induced draft fan and the vertical inverted U-shaped heat pipe heat exchanger, the pipeline between the vertical inverted U-shaped heat pipe heat exchanger and the fifth induced draft fan, and the pipeline between the fifth induced draft fan and the turbine.

[0022] Temperature indicating and control instruments are connected to the pipelines between the turbine and the chemical distillation reactor, the pipelines between the turbine and the domestic heating system, and the pipelines between the turbine and the steam condenser.

[0023] The bag filter is connected to a pressure indicator.

[0024] The inlet pipe of the second induced draft fan, the outlet pipe of the molecular sieve adsorber, the vertical inverted U-shaped heat pipe heat exchanger, the turbine and the accumulator are all connected to dust concentration indicators.

[0025] The outlet pipe of the gas separation membrane module is connected to a flow indicator instrument;

[0026] The vertical inverted U-shaped heat pipe heat exchanger is connected to a liquid level indicator.

[0027] The temperature indicator control instrument, pressure indicator control instrument, pressure indicator, dust concentration indicator, flow indicator, and liquid level indicator are all connected to the data integration control cabinet.

[0028] In this invention, the data integration control cabinet has a built-in DCS control system.

[0029] Preferably, the vertical inverted U-shaped heat pipe heat exchanger has an inverted layout, the heat pipe structure is completely closed, and the interior is filled with a special heat exchange medium.

[0030] The heat pipe is divided into an evaporation section, an adiabatic section, and a condensation section along its height.

[0031] The heat exchanger is equipped with a scaling tube, internal thread, and liquid suction core structure on the heat pipe.

[0032] The expansion tube alters the fluid flow state, increases turbulence, reduces boundary layer thickness, and improves heat exchange efficiency; the internal thread guides the fluid in a spiral flow, improving flow characteristics and reducing flow resistance; the wick structure further increases the heat exchange area and efficiency.

[0033] In addition, the heat exchanger is equipped with electrically adjustable height feet at the bottom. Adjusting the height of the feet can precisely change the tilt angle of the heat exchanger, optimize the flow and phase change process of the working fluid inside the heat pipe, enhance capillary action, accelerate the reflux of the working fluid, and improve heat transfer efficiency and overall heat exchange performance.

[0034] Adjustable feet allow the heat exchanger to flexibly adjust its tilt angle according to dynamic changes in heat load, optimizing heat exchange performance and ensuring efficient and stable heat exchange under different heat load conditions. Depending on actual design requirements, the heat exchange tubes can be flexibly designed with a single or double bend structure, facilitating engineering applications and system integration. Through optimized design, this heat exchanger can control the extreme temperature difference between hot and cold heat exchange streams within the range of 0.5-2℃, effectively improving heat exchange efficiency and achieving efficient energy utilization.

[0035] The bag filter uses a new type of high-temperature resistant high-silica fiber material to make filter bags. Through gradient composite spinning technology, polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), high-silica fibers and nano-sized titanium dioxide particles are three-dimensionally interwoven to form a gradient filtration structure with "sparse outer layer and dense inner layer". The outer layer uses PTFE coarse fibers with a diameter of 8-12μm to build an impact-resistant skeleton, the middle layer uses 4-7μm PPS fibers to form the main filtration layer, and the inner layer is implanted with a 1-3μm high-silica nanofiber membrane, which further improves the filtration accuracy, dust removal efficiency and durability of the filter bag. Meanwhile, the pulse cleaning system was optimized and designed using a differential pressure-time dual-variable intelligent control system. Sixteen pressure sensors distributed throughout the housing collect real-time differential pressure data inside and outside the filter bags, and a fuzzy control algorithm dynamically adjusts the cleaning parameters: when the differential pressure is ≤1300Pa, an energy-saving mode is activated, automatically reducing the pulse width to 0.15s and extending the blowing interval to 140s; when the differential pressure exceeds 1700Pa, an enhanced cleaning mode is entered, increasing the pulse width to 0.25s and initiating staggered row-by-row blowing, achieving precise cleaning and energy-saving operation. Furthermore, acoustic cleaning technology is applied, integrating a wide-frequency array acoustic cleaning device with 16 frequency-adjustable piezoelectric ceramic transducers (operating frequency covering 40-300Hz). PLC programming enables a composite cleaning mode of "low-frequency resonance + high-frequency stripping": the mechanical vibration generated in the low-frequency range (40-80Hz) causes fatigue fracture in the sticky dust layer, while the cavitation effect in the high-frequency range (150-300Hz) strips fine particles from the gaps in the filter bag fibers. The acoustic emission power can be steplessly adjusted within the range of 50-150dB. When the detected dust concentration is >70g / m³, the enhanced mode is automatically activated, and the emission interval is shortened to 20s. This effectively avoids the damage that traditional dust removal methods may cause to the filter bags, significantly improves the dust removal efficiency, extends the service life of the filter bags, and ensures the high efficiency and reliability of the bag filter during long-term operation.

[0036] Preferably, the packing material of the molecular sieve adsorber is ZIF-8 (zinc-2-methylimidazolium framework), which is formed by the assembly of zinc ions (Zn²⁺) and 2-methylimidazolium ligands through coordination bonds. It has a regular porous structure with a pore size of about 11 Å, has high adsorption capacity for nitrogen oxides and sulfur oxides and good chemical stability, and is suitable for efficient adsorption and purification of acidic gases in industrial flue gas.

[0037] In this invention, the mixed matrix membrane of the gas separation membrane assembly is specifically composed of polybenzimidazole (PBI) as the polymer matrix and ZSM-5 zeolite as the inorganic filler. Polybenzimidazole (PBI) possesses excellent high-temperature resistance (long-term operating temperature ≥260℃) and chemical stability; its nitrogen heterocyclic structure can react with polar gas molecules (such as NO). x SO x) Generate specific interactions; ZSM-5 zeolite, as an inorganic filler, has a regular ten-membered ring pore structure (pore size of about 0.55nm), which can accurately sieve gas molecules and improve the selectivity of the membrane. The hybrid matrix membrane formed by the combination of the two has the flexibility of PBI and the high separation efficiency of ZSM-5, which can significantly improve the separation performance of nitrogen oxides and sulfur oxides.

[0038] The steam turbine power generation unit adopts a dual-rotor structure design with high and low pressure cylinders arranged in parallel. By implementing cylinder reheat technology, the thermal efficiency is significantly improved, reaching over 49%. In terms of material selection, the unit utilizes ultra-high temperature alloy materials, specifically the nickel-based high-temperature alloy GH4169 (UNSN07718). This material possesses excellent high-temperature resistance, high-pressure resistance, and corrosion resistance, effectively extending the turbine's service life. The energy accumulator uses high-nickel cathode material NCM811 (LiNi0.8Co0.1Mn0.1O2), with a primary particle size controlled at 10-15μm and a surface modified by 5% magnesium oxide (MgO) coating, achieving a reversible specific capacity of 185mAh / g and supporting a cell mass energy density ≥350Wh / kg. It also uses nano-silicon-carbon anode material, with a core of nano-silicon particles (80nm in diameter) and an outer layer of 10nm thick pyrolytic carbon, achieving an initial efficiency capacity >480mAh / g and a cycle life exceeding 1200 cycles (0.5C charge / discharge). The superior performance of these materials enables the cell mass energy density to reach 300-450Wh / kg, significantly improving the energy storage capacity of the energy storage system. Simultaneously, the three-stage utilization process can effectively recover water vapor under different temperature, pressure, and flow conditions, making the waste heat recovery system more flexible and adaptable. This allows the entire system to maintain high heat exchange efficiency across different temperature ranges, meeting the needs of various industrial production processes.

[0039] The working principle of this invention is as follows:

[0040] (1) Data acquisition terminal connection (input signal)

[0041] Baghouse dust collector

[0042] Sixteen pressure sensors (distributed inside and outside the filter bag) are connected to collect filter bag differential pressure data in real time (≤1300Pa / >1700Pa threshold triggers different dust removal modes).

[0043] Integrated dust concentration sensor to monitor outlet dust concentration (automatically activates acoustic cleaning enhancement mode when >70g / m³).

[0044] Molecular sieve adsorber

[0045] Configure an acid gas concentration sensor (SOx / NOx detection module) to monitor the pollutant content in the flue gas after secondary purification and provide feedback on the adsorbent saturation status.

[0046] Built-in temperature and pressure sensors monitor the thermodynamic parameters of the adsorption process (such as adsorption temperature 200-300℃ and pressure 0.5-1.0MPa).

[0047] Gas separation membrane module

[0048] Connect differential pressure sensors on both sides of the membrane to monitor the degree of membrane fouling (sudden pressure change can trigger an early warning of membrane blockage).

[0049] An integrated gas flow sensor records the flue gas flow rate after three-stage purification in real time, optimizing the operating parameters of the membrane module.

[0050] Vertical inverted U-shaped heat pipe heat exchanger

[0051] Temperature sensors (accuracy ±0.5℃) are deployed in the evaporation and condensation sections to monitor the phase change temperature of the working fluid (e.g., the boiling point of CH2FCF3 is -26.5℃).

[0052] Pressure sensors are installed at the inlet and outlet of the heat pipe to monitor fluctuations in the working fluid circulation pressure.

[0053] The electrically adjustable height feet are equipped with angle sensors to provide feedback on the heat exchanger tilt angle (adjustment accuracy ±0.1°) and are linked to heat load data.

[0054] Turbines and generators

[0055] The turbine inlet is connected to a steam temperature / pressure sensor (high temperature and high pressure steam parameters: temperature 500-550℃, pressure 10-15MPa), and the outlet is connected to a medium temperature and medium pressure steam parameter sensor (temperature 200-300℃, pressure 2-5MPa).

[0056] The generator is equipped with an energy parameter monitoring module (voltage, current, frequency, power factor) to upload power generation efficiency data in real time (thermal efficiency ≥49%).

[0057] Accumulator and Steam Utilization Terminal

[0058] The energy storage device is connected to cell status sensors (voltage, capacity, temperature) to monitor the operating status of the energy storage system (energy density 300-450W·h / kg).

[0059] Steam flow / temperature sensors are installed at the inlet of chemical distillation reactors and residential heating systems to provide feedback on end-user heat demand and optimize steam distribution strategies.

[0060] induced draft fan unit

[0061] Each induced draft fan is equipped with a speed sensor and a current sensor to monitor the fan's operating power (air volume adjustment range 5000-20000m³ / h) and avoid the risk of surge.

[0062] (2) Control command output terminal connection (output signal)

[0063] Baghouse dust collector control

[0064] Send a differential pressure-time dual-variable control signal to the pulse cleaning system (energy-saving mode / enhanced mode switching, pulse width 0.15-0.25s, pulse interval 140-20s).

[0065] Send frequency / power adjustment commands (40-300Hz wideband signal, 50-150dB power stepless adjustment) to the acoustic cleaning device.

[0066] Heat pipe heat exchanger regulation

[0067] Outputs an electrically adjustable height pad drive signal (servo motor control) to dynamically adjust the tilt angle (0-15° adjustable) and optimize the working fluid return efficiency.

[0068] Based on the temperature difference between hot and cold fluids (target range of 0.5-2℃), remotely control the operating parameters (such as turbulence intensity adjustment) of the scaling tube and internal thread structure.

[0069] Turbine and Steam Distribution

[0070] The steam utilization path is controlled by pipeline valve actuators in three stages: high-temperature and high-pressure steam is preferentially used to drive turbine power generation, medium-temperature and medium-pressure steam is transported to chemical reactors, and low-temperature and low-pressure steam is switched to the heating system.

[0071] Send turbine nozzle opening command to adjust steam flow rate (the flow rate increases to 300-500m / s after expansion) and optimize mechanical energy conversion efficiency.

[0072] Collaborative Control

[0073] It connects to the DCS control system to realize remote monitoring interface data synchronization, and supports real-time viewing of equipment operation curves (such as heat exchange efficiency trends and dust concentration fluctuation graphs) on mobile phones / PCs.

[0074] (3) Features of the connection architecture

[0075] Full-process closed-loop control: From flue gas purification (dust collector pressure difference → dust removal strategy) to waste heat utilization (heat pipe temperature → steam distribution), a data closed loop is formed with a response time of <200ms.

[0076] Multi-protocol compatibility: Supports industrial buses such as Modbus, Profibus, and Ethernet / IP, enabling plug-and-play functionality for devices from different brands (such as sensors and actuators).

[0077] Fault self-healing mechanism: When a device parameter is abnormal (such as heat pipe pressure difference exceeding 1.5MPa), the instrument module automatically triggers backup control logic (such as switching to single-bend heat pipe operation mode) and sends a warning message to the operation and maintenance terminal.

[0078] Through the above connections, the intelligent instrument module realizes full equipment status monitoring, full process precise control, and full-condition adaptive adjustment of the flue gas waste heat recovery system, providing intelligent support for the efficient and stable operation of the system.

[0079] Another objective of this invention is to provide a method for recovering waste heat from flue gas based on a novel vertical inverted U-shaped heat pipe heat exchanger. The system described above includes: high-temperature flue gas emitted from a chemical plant is first transported through pipelines to a baghouse dust collector for primary purification to remove particulate matter; subsequently, the purified high-temperature flue gas continues to flow through pipelines into a molecular sieve adsorber for secondary purification, effectively removing acidic gases. After these two stages of purification, the high-temperature flue gas continues to flow through pipelines into a gas separation membrane module for further separation of residual acidic gases. The purified high-temperature gas then undergoes efficient heat exchange with low-temperature industrial wastewater in the novel vertical inverted U-shaped heat pipe heat exchanger. During this process, the flue gas releases heat, its temperature decreases, and the resulting low-temperature flue gas is returned to the baghouse dust collector; while the low-temperature industrial wastewater absorbs heat and transforms into high-temperature steam. Based on the steam's temperature and pressure gradients, the wastewater is then distributed and utilized in a tertiary manner. The electricity generated by the high-temperature, high-pressure steam-driven power generation unit is integrated into the energy storage system and public power grid, ensuring a stable supply of electricity for factory production and residential use, and guaranteeing the efficient operation of the power system. Medium-temperature, medium-pressure steam is directly transported to chemical distillation reactors, precisely supplying the required heat energy for chemical production processes, ensuring smooth production. Low-temperature, low-pressure steam is introduced into home heating systems. This achieves efficient utilization and tiered distribution of heat energy, maximizing the overall efficiency of energy utilization.

[0080] Specifically, the following steps are included:

[0081] S1. After the high-temperature flue gas is discharged from the chimney, it is transported to the bag filter by the first induced draft fan for the first-stage purification process.

[0082] S2. The high-temperature flue gas after primary purification is transported to the molecular sieve adsorber by the second induced draft fan to carry out the secondary purification process.

[0083] S3. The high-temperature flue gas after secondary purification is transported to the gas separation membrane module under the drive of the third induced draft fan to carry out the tertiary purification process.

[0084] S4. The high-temperature flue gas after three-stage purification is transported to the vertical inverted U-shaped heat pipe heat exchanger under the drive of the fourth induced draft fan. In this heat exchanger, the working fluid in the evaporation section of the new inverted U-shaped heat pipe is vaporized by heat absorption, which efficiently absorbs the heat of the high-temperature flue gas and rapidly cools the flue gas to low-temperature flue gas. Then, it is transported back to the molecular sieve adsorber through the pipeline. At the same time, the working fluid vapor rises to the condensation section in the closed inverted U-shaped heat pipe and liquefies and releases heat. The heat is used to heat the industrial low-temperature wastewater and cause it to vaporize into high-temperature and high-pressure water vapor. The condensed working fluid liquid flows back along the heat pipe wall and comes into countercurrent contact with the rising working fluid vapor.

[0085] S5. High-temperature and high-pressure steam, after vaporization, is introduced into the turbine through the fifth induced draft fan. In this device, the high-temperature and high-pressure steam is precisely guided to the nozzle area of ​​the steam turbine. When the steam passes through the nozzle, it undergoes an expansion process, causing the pressure and temperature parameters to decrease, while the steam velocity increases accordingly. The high-speed flowing steam then impacts the turbine blades, driving the turbine to rotate. This process realizes the efficient conversion of steam thermal energy into mechanical energy. The rotational motion of the turbine is transmitted to the generator through the main shaft. Inside the generator, the relative motion between the stator and rotor is based on the principle of electromagnetic induction, converting mechanical energy into electrical energy. The steam that has completed the energy conversion task is discharged from the turbine and then enters the steam condenser, chemical distillation reactor, and domestic heating system. In the steam condenser, the steam is cooled and condensed into liquid water, which is then transported to the water storage tank by the feed water pump, thus forming a closed loop system that ensures the continuous and efficient use of energy.

[0086] S6. Based on the temperature and pressure gradients of steam, the system performs three-stage utilization through distribution. The electrical energy generated by the high-temperature and high-pressure steam driving the turbine and generator is integrated into the energy storage and public power grid system, achieving a stable supply of electricity for factory production and residential use, and ensuring the efficient operation of the power system. The medium-temperature and medium-pressure steam generated in the turbine is directly transported to the chemical distillation reactor. The low-temperature and low-pressure steam generated in the turbine is introduced into the home heating system, thereby achieving efficient utilization and tiered distribution of thermal energy and maximizing the comprehensive utilization efficiency of energy.

[0087] S7. The overall system integrates an intelligent instrument module to achieve interconnection with relevant equipment, and is responsible for signal acquisition, transmission and precise control; based on the DCS control system in the data integration control cabinet, it monitors and automatically optimizes equipment parameters in real time to ensure stable and efficient operation of the process.

[0088] In the process of this invention, the system monitors and identifies the temperature and pressure of steam, and uses high-temperature and high-pressure, medium-temperature and medium-pressure, and low-temperature and low-pressure steam through pipeline valves for turbine steam engine power generation, heating of factory equipment (such as chemical reactors), and home heating, respectively.

[0089] This invention incorporates intelligent control technology, deeply integrating it with the Internet of Things, big data, and artificial intelligence to achieve real-time monitoring and autonomous adjustment of system operating parameters. Simultaneously, it features remote monitoring capabilities, enabling early warning of potential faults. This series of intelligent measures not only significantly reduces labor costs but also greatly improves the system's operational stability and security.

[0090] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0091] (1) High efficiency in waste heat recovery

[0092] The core component, the vertical inverted U-shaped heat pipe heat exchanger, adopts an inverted layout and a closed heat pipe structure. It is filled with CH2FCF3 working fluid and divided into evaporation, adiabatic, and condensation sections along its height. With the help of scaling tubes, internal threads, and liquid wick structure, it significantly enhances the degree of turbulence and expands the heat exchange area. It controls the extreme temperature difference between hot and cold streams within 0.5-2℃, and improves the heat exchange efficiency from 50%-55% in traditional systems to 70%-75%, achieving efficient utilization of low-grade waste heat.

[0093] The electrically adjustable height feet design can dynamically adjust the tilt angle of the heat exchanger, optimize the working fluid flow and phase change process, accelerate reflux, adapt to different heat load conditions, and ensure stable and efficient operation of the equipment in a wide temperature range.

[0094] (2) Excellent flue gas purification performance

[0095] The bag filter uses high-silica fiber composite filter bags, which form a "loose on the outside and dense on the inside" filtration structure through gradient composite spinning technology (PTFE / PPS / high-silica fiber + nano TiO2). The filtration efficiency for 0.3μm dust reaches 99.92%, and the equivalent pore size is reduced to 4μm. Combined with differential pressure-time intelligent pulse cleaning and broadband ultrasonic cleaning technology, the cleaning efficiency is improved by 28%, and the filter bag life is extended from 18 months to 26 months, reducing dust wear and clogging of subsequent equipment.

[0096] Molecular sieve adsorbers are filled with metal-organic frameworks (such as ZIF), and gas separation membrane modules use polybenzimidazole (PBI)-based mixed matrix membranes, which significantly improves the adsorption and separation efficiency of NOx / SOx. The two-stage + three-stage purification process effectively removes acidic gases, reduces the corrosiveness of flue gas, and ensures the stability of subsequent heat exchange and power generation processes.

[0097] (3) Cascaded utilization and efficient conversion of energy

[0098] The steam turbine power generation unit adopts a dual-rotor structure with high and low pressure cylinders and cylinder reheat technology, achieving a thermal efficiency of over 49%. Ultra-high temperature alloys and ceramic matrix composite materials enhance the equipment's resistance to high temperatures and pressures, extending its service life. The three-stage utilization process of high-temperature and high-pressure steam power generation, medium-temperature and medium-pressure steam heating, and low-temperature and low-pressure steam heating maximizes the comprehensive utilization rate of waste heat, making it suitable for different industrial and civil applications.

[0099] The energy storage device uses high-nickel positive electrode (NCM811, etc.) and nano-silicon-carbon negative electrode material, with a cell energy density of 300-450W·h / kg, realizing stable storage and output of electrical energy and enhancing the reliability of system power supply.

[0100] (4) Advantages of intelligent control and system integration

[0101] The integrated smart instrument module collects equipment parameters (such as differential pressure, temperature, and flow rate) in real time. Through fuzzy algorithms and IoT technology, it dynamically optimizes operating strategies (such as dust removal parameters, heat pipe tilt angle, and steam distribution ratio), achieving fully automatic monitoring and fault early warning, reducing manual intervention costs, and improving system stability by more than 30%.

[0102] The equipment has a compact layout (single / double bend inverted U-shaped heat pipe design) and simplified piping. Compared with traditional multi-stage heat exchanger systems, it reduces the floor space by 40%, reduces maintenance costs by 25%, and has strong adaptability, making it flexible to be integrated into flue gas treatment processes in industries such as chemical and power.

[0103] (5) Significant energy-saving and environmental protection benefits

[0104] The low temperature difference heat exchange characteristic enables the efficient utilization of low-grade waste heat (such as flue gas at 100-300℃) that was originally difficult to recover, reducing the consumption of fossil energy; the purified flue gas is recycled back to the molecular sieve adsorber, reducing system energy consumption, and the overall energy saving rate reaches more than 35%.

[0105] Highly efficient removal of dust and NO x SO x Reduce air pollutant emissions, meet stringent environmental standards, and contribute to the achievement of "dual carbon" goals.

[0106] (6) Advantages compared with existing technologies

[0107] Heat exchange efficiency: Breaking through the temperature difference limitation of traditional heat exchangers, it achieves near isothermal heat exchange and significantly improves the utilization capacity of low-grade waste heat.

[0108] Anti-fouling properties: The expansion tube + internal thread + liquid suction core structure reduces the thickness of the fluid boundary layer, inhibits scaling, and extends the maintenance cycle by more than 50%.

[0109] System flexibility: Adjustable heat pipe layout and three-stage steam utilization process adapt to different operating conditions (high temperature and high humidity, corrosive flue gas), improving operational adaptability by 60%.

[0110] In summary, this invention, through core equipment innovation, multi-technology collaboration, and intelligent control, constructs an efficient, stable, and environmentally friendly flue gas waste heat recovery system, providing a breakthrough solution for industrial energy conservation and emission reduction. Attached Figure Description

[0111] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0112] Figure 1 This is a structural diagram of the vertical inverted U-shaped heat pipe heat exchanger of the present invention;

[0113] Figure 2 This is a 3D diagram of the U-shaped heat exchange tube in the vertical inverted U-shaped heat pipe heat exchanger of the present invention, where a is a single bend and b is a double bend;

[0114] Figure 3 This is a structural diagram of the flue gas waste heat recovery system of the present invention;

[0115] In the figure:

[0116] 1-Chimney; 21-First induced draft fan; 22-Second induced draft fan; 23-Third induced draft fan; 24-Fourth induced draft fan; 25-Fifth induced draft fan; 3-Bag filter; 4-Molecular sieve adsorber; 5-Gas separation membrane module; 6-Vertical inverted U-shaped heat pipe heat exchanger; 7-Turbine; 8-Generator; 9-Public power grid; 10-Accumulator; 11-Chemical distillation reactor; 12-Door heating system; 13-Steam condenser; 14-Water storage tank; 15-Water pump;

[0117] Temperature indication and control instruments: TIC01, TIC02, TIC03, TIC04, TIC05, TIC06, TIC07, TIC08, TIC09, TIC10, TIC11, TIC12, TIC13;

[0118] Pressure indicating and control instruments: PIC01, PIC02, PIC03, PIC04, PIC05, PIC06, PIC07, PIC08, PIC09;

[0119] Pressure indicator: PI01;

[0120] Dust concentration indicating instruments: S01, S02, S03, S04, S05;

[0121] Flow indicator: FI01;

[0122] Liquid level indicator: LG. Detailed Implementation

[0123] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0124] Example 1

[0125] See Figure 1-3 This embodiment provides a flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger, characterized in that it includes:

[0126] 3. Bag filter; 4. Molecular sieve adsorber; 5. Gas separation membrane module; 6. Vertical inverted U-shaped heat pipe heat exchanger; 7. Turbine; 8. Generator; and 10. Accumulator.

[0127] Among them, the bag filter 3, the molecular sieve adsorber 4, the gas separation membrane module 5, the vertical inverted U-shaped heat pipe heat exchanger 6 and the turbine 7 are connected in sequence.

[0128] The turbine 7 is connected to the generator 8 and the accumulator 10 respectively.

[0129] In this embodiment, the flue gas waste heat recovery system further includes: a chimney 1 and induced draft fans; the induced draft fans include a first induced draft fan 21, a second induced draft fan 22, a third induced draft fan 23, a fourth induced draft fan 24, and a fifth induced draft fan 25;

[0130] The first induced draft fan 21 is located between the chimney 1 and the bag filter 3; the second induced draft fan 22 is located between the bag filter 3 and the molecular sieve adsorber 4; the third induced draft fan 23 is located between the molecular sieve adsorber 4 and the gas separation membrane assembly 5; the fourth induced draft fan 24 is located between the gas separation membrane assembly 5 and the vertical inverted U-shaped heat pipe heat exchanger 6; and the fifth induced draft fan 25 is located between the vertical inverted U-shaped heat pipe heat exchanger 6 and the turbine 7.

[0131] The vertical inverted U-shaped heat pipe heat exchanger 6 is also connected to the first induced draft fan 21.

[0132] The vertical inverted U-shaped heat pipe heat exchanger 6 is also connected to the induced draft fan 2 between the chimney 1 and the bag filter 3.

[0133] In this embodiment, the flue gas waste heat recovery system also includes: a public power grid 9, a chemical distillation reactor 11, a domestic heating system 12, a steam condenser 13, a water storage tank 14, and a water pump 15;

[0134] Generator 8 is connected to the public power grid 9;

[0135] The turbine 7 is also connected to the chemical distillation reactor 11, the domestic heating system 12, and the steam condenser 13, respectively.

[0136] The steam condenser 13 is connected in sequence to the water storage tank 14, the water pump 15, and the vertical inverted U-shaped heat pipe heat exchanger 6.

[0137] In this embodiment, the flue gas waste heat recovery system further includes: an integrated smart instrument module, a data integration control cabinet 17, and a computer 18; the data integration control cabinet 17 and the computer 18 are connected.

[0138] The integrated intelligent instrument module includes: temperature indicating and control instrument, pressure indicating and control instrument, pressure indicating instrument, dust concentration indicating instrument, flow indicating instrument and liquid level indicating instrument;

[0139] Temperature and pressure indicators are connected to the following pipelines: the pipeline between the first induced draft fan 21 and the bag filter 3; the pipeline between the bag filter 3 and the second induced draft fan 22; the pipeline between the second induced draft fan 22 and the molecular sieve adsorber 4; the pipeline between the molecular sieve adsorber 4 and the third induced draft fan 23; the pipeline between the third induced draft fan 23 and the gas separation membrane assembly 5; the pipeline between the gas separation membrane assembly 5 and the fourth induced draft fan 24; the pipeline between the fourth induced draft fan 24 and the vertical inverted U-shaped heat pipe heat exchanger 6; the pipeline between the vertical inverted U-shaped heat pipe heat exchanger 6 and the fifth induced draft fan 25; and the pipeline between the fifth induced draft fan 25 and the turbine 7.

[0140] Temperature indicating and control instruments are connected to the pipelines between the turbine 7 and the chemical distillation reactor 11, the pipelines between the turbine 7 and the domestic heating system 12, and the pipelines between the turbine 7 and the steam condenser 13.

[0141] The bag filter 3 is connected to a pressure indicator instrument;

[0142] The inlet pipe of the second induced draft fan 22, the outlet pipe of the molecular sieve adsorber 4, the vertical inverted U-shaped heat pipe heat exchanger 6, the turbine 7 and the accumulator 10 are all connected to dust concentration indicators.

[0143] The outlet pipe of the gas separation membrane module 5 is connected to a flow indicator instrument;

[0144] The vertical inverted U-shaped heat pipe heat exchanger 6 is connected to a liquid level indicator.

[0145] Temperature indicator control instrument, pressure indicator control instrument, pressure indicator instrument, dust concentration indicator instrument, flow indicator instrument and liquid level indicator instrument are all connected to the data integration control cabinet 17.

[0146] To further optimize the above technical solution, the vertical inverted U-shaped heat pipe heat exchanger 6 has an inverted layout, the heat pipe structure is completely closed, and the inside is filled with a special heat exchange working fluid. The heat pipe is divided into an evaporation section, an adiabatic section and a condensation section along the height direction.

[0147] Add a scaling tube, internal thread, and wick structure to the heat pipe;

[0148] In addition, the heat exchanger is equipped with electrically adjustable height feet at the bottom;

[0149] The heat exchange tubes have a single-bend or double-bend structure.

[0150] The expansion tube alters the fluid flow state, increases turbulence, reduces boundary layer thickness, and improves heat exchange efficiency; the internal thread guides the fluid in a spiral flow, improving flow characteristics and reducing flow resistance; the wick structure further increases the heat exchange area and efficiency.

[0151] In addition, the heat exchanger is equipped with electrically adjustable height feet at the bottom. Adjusting the height of the feet can precisely change the tilt angle of the heat exchanger, optimize the flow and phase change process of the working fluid inside the heat pipe, enhance capillary action, accelerate the reflux of the working fluid, and improve heat transfer efficiency and overall heat exchange performance.

[0152] Adjustable feet allow the heat exchanger to flexibly adjust its tilt angle according to dynamic changes in heat load, optimizing heat exchange performance and ensuring efficient and stable heat exchange under different heat load conditions. Depending on actual design requirements, the heat exchange tubes can be flexibly designed with a single or double bend structure, facilitating engineering applications and system integration. Through optimized design, this heat exchanger can control the extreme temperature difference between hot and cold heat exchange streams within the range of 0.5-2℃, effectively improving heat exchange efficiency and achieving efficient energy utilization.

[0153] The bag filter uses a new type of high-temperature resistant high-silica fiber material to make filter bags. Through gradient composite spinning technology, polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), high-silica fibers and nano-sized titanium dioxide particles are three-dimensionally interwoven to form a gradient filtration structure with "sparse outer layer and dense inner layer". The outer layer uses PTFE coarse fibers with a diameter of 8-12μm to build an impact-resistant skeleton, the middle layer uses 4-7μm PPS fibers to form the main filtration layer, and the inner layer is implanted with a 1-3μm high-silica nanofiber membrane, which further improves the filtration accuracy, dust removal efficiency and durability of the filter bag. Meanwhile, the pulse cleaning system was optimized and designed using a differential pressure-time dual-variable intelligent control system. Sixteen pressure sensors distributed throughout the housing collect real-time differential pressure data inside and outside the filter bags, and a fuzzy control algorithm dynamically adjusts the cleaning parameters: when the differential pressure is ≤1300Pa, an energy-saving mode is activated, automatically reducing the pulse width to 0.15s and extending the blowing interval to 140s; when the differential pressure exceeds 1700Pa, an enhanced cleaning mode is entered, increasing the pulse width to 0.25s and initiating staggered row-by-row blowing, achieving precise cleaning and energy-saving operation. Furthermore, acoustic cleaning technology is applied, integrating a wide-frequency array acoustic cleaning device with 16 frequency-adjustable piezoelectric ceramic transducers (operating frequency covering 40-300Hz). PLC programming enables a composite cleaning mode of "low-frequency resonance + high-frequency stripping": the mechanical vibration generated in the low-frequency range (40-80Hz) causes fatigue fracture in the sticky dust layer, while the cavitation effect in the high-frequency range (150-300Hz) strips fine particles from the gaps in the filter bag fibers. The acoustic emission power can be steplessly adjusted within the range of 50-150dB. When the detected dust concentration is >70g / m³, the enhanced mode is automatically activated, and the emission interval is shortened to 20s. This effectively avoids the damage that traditional dust removal methods may cause to the filter bags, significantly improves the dust removal efficiency, extends the service life of the filter bags, and ensures the high efficiency and reliability of the bag filter during long-term operation.

[0154] The packing material of the molecular sieve adsorber is ZIF-8 (zinc-2-methylimidazolium framework), a zeolite imidazolium ester framework material. It is formed by the assembly of zinc ions (Zn²⁺) and 2-methylimidazolium ligands through coordination bonds. It has a regular porous structure with a pore size of about 11 Å, and has high adsorption capacity for nitrogen oxides and sulfur oxides and good chemical stability. It is suitable for the efficient adsorption and purification of acidic gases in industrial flue gas.

[0155] In this invention, the mixed matrix membrane of the gas separation membrane module is specifically composed of polybenzimidazole (PBI) as the polymer matrix and ZSM-5 zeolite as the inorganic filler. PBI possesses excellent high-temperature resistance (long-term operating temperature ≥260℃) and chemical stability; its nitrogen heterocyclic structure can specifically interact with polar gas molecules (such as NOx and SOx). ZSM-5 zeolite, as the inorganic filler, has a regular ten-membered ring pore structure (pore size approximately 0.55 nm), which can accurately sieve gas molecules and improve membrane selectivity. The mixed matrix membrane formed by combining the two combines the flexibility of PBI with the high separation efficiency of ZSM-5, significantly improving the separation performance of nitrogen oxides and sulfur oxides.

[0156] The steam turbine power generation unit adopts a dual-rotor structure design with high and low pressure cylinders arranged in parallel. By implementing cylinder reheat technology, the thermal efficiency is significantly improved, reaching over 49%. In terms of material selection, the unit utilizes ultra-high temperature alloy materials, specifically the nickel-based high-temperature alloy GH4169 (UNSN07718). This material possesses excellent high-temperature resistance, high-pressure resistance, and corrosion resistance, effectively extending the turbine's service life. The energy accumulator uses high-nickel cathode material NCM811 (LiNi0.8Co0.1Mn0.1O2), with a primary particle size controlled at 10-15μm and a surface modified by 5% magnesium oxide (MgO) coating, achieving a reversible specific capacity of 185mAh / g and supporting a cell mass energy density ≥350Wh / kg. It also uses nano-silicon-carbon anode material, with a core of nano-silicon particles (80nm in diameter) and an outer layer of 10nm thick pyrolytic carbon, achieving an initial efficiency capacity >480mAh / g and a cycle life exceeding 1200 cycles (0.5C charge / discharge). The superior performance of these materials enables the cell mass energy density to reach 300-450Wh / kg, significantly improving the energy storage capacity of the energy storage system. Simultaneously, the three-stage utilization process can effectively recover water vapor under different temperature, pressure, and flow conditions, making the waste heat recovery system more flexible and adaptable. This allows the entire system to maintain high heat exchange efficiency across different temperature ranges, meeting the needs of various industrial production processes.

[0157] Example 2

[0158] This embodiment provides a three-stage utilization process and method for flue gas waste heat recovery based on a novel vertical inverted U-shaped heat pipe heat exchanger. The process includes the following steps:

[0159] S1. The high-temperature flue gas generated during the chemical production process is conveyed to the bag filter 3 by the first induced draft fan 21 for primary purification. The bag filter 3, with its unique filtration mechanism, effectively captures various fine, dry non-fibrous dust particles and heavy metal pollutants such as mercury carried in the flue gas. This crucial purification step significantly reduces the potential adverse effects of dust on downstream equipment, thereby helping to improve the operational stability and reliability of the entire flue gas treatment system and ensuring its long-term efficient operation.

[0160] S2. The high-temperature flue gas, after primary purification, is conveyed to the molecular sieve adsorber 4 by the second induced draft fan 22 for secondary purification. The molecular sieve fully absorbs SO₂ contained in the flue gas. x (such as sulfur dioxide) and NO x Acidic gases (such as nitric oxide and nitrogen dioxide) are used to achieve preliminary purification of flue gas, effectively reducing the potential harm to the environment from subsequent emissions.

[0161] S3. The high-temperature flue gas, after secondary purification, is transported to the gas separation membrane module 5 under the drive of the third induced draft fan 23 to carry out a tertiary purification process, further separating SO2 contained in the flue gas. x (such as sulfur dioxide) and NO x Acidic residual gases such as nitric oxide and nitrogen dioxide.

[0162] S4. The high-temperature flue gas, after undergoing three-stage purification, is introduced into the vertical inverted U-shaped heat pipe heat exchanger 6. Inside the vertical inverted U-shaped heat pipe heat exchanger 6, the working fluid in the evaporation section of the novel inverted U-shaped heat pipe undergoes heat absorption and vaporization, efficiently absorbing heat from the high-temperature flue gas, rapidly cooling the flue gas to a low-temperature state, and then returning it to the molecular sieve adsorber 4 through pipelines. Simultaneously, the working fluid vapor rises to the condensation section within the sealed inverted U-shaped heat pipe and liquefies, releasing heat. This heat is used to heat the industrial low-temperature wastewater, causing it to vaporize into high-temperature water vapor. The condensed working fluid liquid flows back along the heat pipe wall, contacting the rising working fluid vapor in a counter-current flow. This counter-current heat exchange mode enhances heat transfer efficiency, improves the overall performance of the heat exchange tube, accelerates the heat transfer process, and lays the foundation for waste heat utilization.

[0163] In this step, the vertical inverted U-shaped heat pipe heat exchanger 6 is arranged in an inverted layout, with a completely enclosed heat pipe structure filled with a specialized heat exchange medium. The heat pipes are divided into evaporation, adiabatic, and condensation sections along their height. The heat exchanger incorporates a scaling tube, internal threads, and a wick structure on the heat pipes. The scaling tube alters the fluid flow state, increasing turbulence, reducing boundary layer thickness, and improving heat exchange efficiency; the internal threads guide the fluid in a spiral flow, improving flow characteristics and reducing flow resistance; the wick structure further increases the heat exchange area and efficiency. Furthermore, the heat exchanger is equipped with electrically adjustable height feet at the bottom. Adjusting the height of the feet precisely changes the heat exchanger's tilt angle, optimizing the flow and phase change process of the working medium within the heat pipes, enhancing capillary action, accelerating the reflux of the working medium, and improving heat transfer efficiency and overall heat exchange performance. The adjustable feet allow the heat exchanger to flexibly adjust its tilt angle according to dynamic changes in heat load, optimizing heat exchange effects and ensuring efficient and stable heat exchange under different heat load conditions. Depending on actual design requirements, the heat exchange tubes can be flexibly designed as single-bend or double-bend structures, facilitating engineering applications and system integration. Through optimized design, this heat exchanger can control the extreme temperature difference between hot and cold heat exchange streams within the range of 0.5-2℃, effectively improving heat exchange efficiency and achieving efficient energy utilization.

[0164] S5. In the waste heat power generation system, high-temperature, high-pressure steam, after vaporization, is introduced into turbine 7 via the fifth induced draft fan 25. Within this device, the high-temperature, high-pressure steam is precisely guided to the nozzle area of ​​the steam turbine. As the steam passes through the nozzle, it undergoes an expansion process, causing a decrease in pressure and temperature parameters, while the steam velocity increases accordingly. The high-speed flowing steam then impacts the turbine blades, driving the turbine to rotate. This process achieves the efficient conversion of steam thermal energy into mechanical energy. The turbine's rotational motion is transmitted to generator 8 via the main shaft. Inside generator 8, the relative motion between the stator and rotor, based on the principle of electromagnetic induction, converts mechanical energy into electrical energy. The steam, having completed its energy conversion, is discharged from turbine 7 and then enters steam condenser 13, chemical distillation reactor 11, and domestic heating system 12. In steam condenser 13, the steam is cooled and condensed into liquid water, which is then pumped to storage tank 14, thus forming a closed-loop system that ensures the continuous and efficient use of energy.

[0165] S6. In the energy conversion and utilization system, the steam is distributed in a three-tiered manner based on its temperature and pressure gradients. The electrical energy generated by the high-temperature, high-pressure steam-driven turbine 7 and generator 8 is integrated into the energy storage system 10 and the public power grid 9, ensuring a stable supply of electricity for factory production and residential use, and guaranteeing the efficient operation of the power system. Medium-temperature, medium-pressure steam is directly transported to the chemical distillation reactor 11, precisely supplying the required heat energy for the chemical production process, ensuring smooth production. Low-temperature, low-pressure steam is introduced into the domestic heating system 12. This achieves efficient utilization and tiered distribution of heat energy, maximizing the overall energy utilization efficiency.

[0166] In this step, the system monitors and identifies the temperature and pressure of the steam, and uses the three types of steam—high temperature and high pressure, medium temperature and medium pressure, and low temperature and low pressure—to generate electricity for turbine 7, heat factory equipment (such as chemical distillation reactor 11), and heat domestic heating system 12 through pipeline valves.

[0167] S7. The overall process piping system integrates an intelligent instrument module to achieve interconnection with related equipment, and is responsible for signal acquisition, transmission and precise control; based on the DCS control system in the data integration control cabinet 17, it monitors and automatically optimizes equipment parameters in real time to ensure stable and efficient operation of the process.

[0168] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0169] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger, characterized in that, include: Baghouse dust collectors, molecular sieve adsorbers, gas separation membrane modules, vertical inverted U-shaped heat pipe heat exchangers, turbines, generators, and accumulators; The bag filter, molecular sieve adsorber, gas separation membrane assembly, vertical inverted U-shaped heat pipe heat exchanger, and turbine are connected in sequence. The turbine is connected to the generator and the accumulator respectively; The vertical inverted U-shaped heat pipe heat exchanger has an inverted layout, the heat pipe structure is completely closed, and the inside is filled with CH2FCF3 working fluid. The heat pipe is divided into an evaporation section, an adiabatic section and a condensation section along the height direction. Add a scaling tube, internal thread, and wick structure to the heat pipe; The heat exchanger is equipped with electrically adjustable height feet at the bottom; The heat pipe has a single-bend or double-bend structure.

2. The flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger according to claim 1, characterized in that, Also includes: Chimney and induced draft fan; the induced draft fan includes a first induced draft fan, a second induced draft fan, a third induced draft fan, a fourth induced draft fan, and a fifth induced draft fan; The first induced draft fan is disposed between the chimney and the bag filter; the second induced draft fan is disposed between the bag filter and the molecular sieve adsorber; the third induced draft fan is disposed between the molecular sieve adsorber and the gas separation membrane assembly; the fourth induced draft fan is disposed between the gas separation membrane assembly and the vertical inverted U-shaped heat pipe heat exchanger; and the fifth induced draft fan is disposed between the vertical inverted U-shaped heat pipe heat exchanger and the turbine. The vertical inverted U-shaped heat pipe heat exchanger is also connected to the first induced draft fan.

3. A flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger according to claim 2, characterized in that, Also includes: Public power grids, chemical distillation reactors, domestic heating systems, steam condensers, water storage tanks, and water pumps; The generator is connected to the public power grid; The turbine is also connected to the chemical distillation reactor, the domestic heating system, and the steam condenser, respectively. The steam condenser is connected in sequence to the water storage tank, the water pump, and the vertical inverted U-shaped heat pipe heat exchanger.

4. A flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger according to claim 3, characterized in that, Also includes: It integrates intelligent instrument modules, data integration control cabinets, and computers; The data integration control cabinet is connected to the computer; The integrated intelligent instrument module includes: a temperature indicating and control instrument, a pressure indicating and control instrument, a pressure indicating instrument, a dust concentration indicating instrument, a flow indicating instrument, and a liquid level indicating instrument; Temperature and pressure indicators are connected to the following pipelines: the pipeline between the first induced draft fan and the bag filter, the pipeline between the bag filter and the second induced draft fan, the pipeline between the second induced draft fan and the molecular sieve adsorber, the pipeline between the molecular sieve adsorber and the third induced draft fan, the pipeline between the third induced draft fan and the gas separation membrane assembly, the pipeline between the gas separation membrane assembly and the fourth induced draft fan, the pipeline between the fourth induced draft fan and the vertical inverted U-shaped heat pipe heat exchanger, the pipeline between the vertical inverted U-shaped heat pipe heat exchanger and the fifth induced draft fan, and the pipeline between the fifth induced draft fan and the turbine. Temperature indicating and control instruments are connected to the pipelines between the turbine and the chemical distillation reactor, the pipelines between the turbine and the domestic heating system, and the pipelines between the turbine and the steam condenser. The bag filter is connected to a pressure indicator. The inlet pipe of the second induced draft fan, the outlet pipe of the molecular sieve adsorber, the vertical inverted U-shaped heat pipe heat exchanger, the turbine and the accumulator are all connected to dust concentration indicators. The outlet pipe of the gas separation membrane module is connected to a flow indicator instrument; The vertical inverted U-shaped heat pipe heat exchanger is connected to a liquid level indicator. The temperature indicator control instrument, pressure indicator control instrument, pressure indicator, dust concentration indicator, flow indicator, and liquid level indicator are all connected to the data integration control cabinet.

5. A flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger according to claim 4, characterized in that, The bag filter uses filter bags made of high-silica fiber material. Polytetrafluoroethylene, polyphenylene sulfide, high-silica fiber and nano-sized titanium dioxide particles are three-dimensionally interwoven through gradient composite spinning technology to form a gradient filtration structure with a loose outer layer and a dense inner layer: the outer layer uses 8-12μm diameter polytetrafluoroethylene coarse fiber to build an impact-resistant skeleton, the middle layer uses 4-7μm diameter polyphenylene sulfide fiber to form the main filtration layer, and the inner layer is implanted with a 1-3μm diameter high-silica nanofiber membrane.

6. A flue gas waste heat recovery system based on a novel vertical inverted U-shaped heat pipe heat exchanger according to claim 5, characterized in that, The molecular sieve adsorber is filled with a metal-organic framework. The gas separation membrane assembly is composed of a mixed matrix membrane, which includes polybenzimidazole and inorganic fillers; The steam turbine power generation unit adopts a dual-rotor structure design with high and low pressure cylinders arranged in parallel.

7. A method for recovering waste heat from flue gas based on a novel vertical inverted U-shaped heat pipe heat exchanger, characterized in that, The system according to claim 6 includes the following steps: S1. After the high-temperature flue gas is discharged from the chimney, it is transported to the bag filter by the first induced draft fan for the first-stage purification process. S2. The high-temperature flue gas after primary purification is transported to the molecular sieve adsorber by the second induced draft fan to carry out the secondary purification process. S3. The high-temperature flue gas after secondary purification is transported to the gas separation membrane module under the drive of the third induced draft fan to carry out the tertiary purification process. S4. The high-temperature flue gas after three-stage purification is transported to the vertical inverted U-shaped heat pipe heat exchanger under the drive of the fourth induced draft fan. In this heat exchanger, the working fluid in the evaporation section of the new inverted U-shaped heat pipe is vaporized by heat absorption, which efficiently absorbs the heat of the high-temperature flue gas and rapidly cools the flue gas to low-temperature flue gas. Then, it is transported back to the molecular sieve adsorber through the pipeline. At the same time, the working fluid vapor rises to the condensation section in the closed inverted U-shaped heat pipe and liquefies and releases heat. The heat is used to heat the industrial low-temperature wastewater and cause it to vaporize into high-temperature and high-pressure water vapor. The condensed working fluid liquid flows back along the heat pipe wall and comes into countercurrent contact with the rising working fluid vapor. S5. High-temperature and high-pressure steam, after vaporization, is introduced into the turbine through the fifth induced draft fan. In this device, the high-temperature and high-pressure steam is precisely guided to the nozzle area of ​​the steam turbine. When the steam passes through the nozzle, it undergoes an expansion process, causing the pressure and temperature parameters to decrease, while the steam velocity increases accordingly. The high-speed flowing steam then impacts the turbine blades, driving the turbine to rotate. This process realizes the efficient conversion of steam thermal energy into mechanical energy. The rotational motion of the turbine is transmitted to the generator through the main shaft. Inside the generator, the relative motion between the stator and rotor is based on the principle of electromagnetic induction, converting mechanical energy into electrical energy. The steam that has completed the energy conversion task is discharged from the turbine and then enters the steam condenser, chemical distillation reactor, and domestic heating system. In the steam condenser, the steam is cooled and condensed into liquid water, which is then transported to the water storage tank by the feed water pump, thus forming a closed loop system that ensures the continuous and efficient use of energy. S6. Based on the temperature and pressure gradients of steam, the system performs three-stage utilization through distribution. The electrical energy generated by the high-temperature and high-pressure steam driving the turbine and generator is integrated into the energy storage and public power grid system, achieving a stable supply of electricity for factory production and residential use, and ensuring the efficient operation of the power system. The medium-temperature and medium-pressure steam generated in the turbine is directly transported to the chemical distillation reactor. The low-temperature and low-pressure steam generated in the turbine is introduced into the home heating system, thereby achieving efficient utilization and tiered distribution of thermal energy and maximizing the comprehensive utilization efficiency of energy. S7. The overall system integrates an intelligent instrument module to achieve interconnection with relevant equipment, and is responsible for signal acquisition, transmission and precise control; based on the DCS control system in the data integration control cabinet, it monitors and automatically optimizes equipment parameters in real time to ensure stable and efficient operation of the process.

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