Solid oxide fuel cell (SOFC) combined cooling heating and power system and method for recycling anode tail gas and combusting tail gas

Abstract

The invention provides an anode tail gas recovery and tail gas combustion combined SOFC (Solid Oxide Fuel Cell) combined cooling heating and power system and method. The system comprises an SOFC power generation module, an input system and a tail gas treatment and energy recovery module, the SOFC power generation module is respectively connected or disconnected with the input system and the tail gas treatment and energy recovery module; according to the anode tail gas recovery and tail gas combustion combined SOFC combined cooling heating and power system and method, the structure of the system can be optimized, anode tail gas shunting and intelligent circulation are achieved, and catalytic combustion cooperative treatment is guaranteed; a multi-grade energy cascade recovery system is realized; and an intelligent cooperative control system is realized.

Description

Technical Field

[0001] This invention relates to the field of distributed energy and fuel cells, and more specifically, to a SOFC (Solar-Fuel Combined Heat and Power) system and method for anode exhaust gas recovery combined with exhaust gas combustion. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are all-solid-state energy conversion devices that directly convert the chemical energy of fuel into electrical energy. They have advantages such as high power generation efficiency, wide fuel adaptability, and no noise. After SOFCs are in operation, they will emit high-temperature anode exhaust gas (rich in unreacted H2, CO, etc.) and cathode exhaust gas (rich in unreacted O2 and N2).

[0003] The current mainstream treatment method is to mix these two exhaust gases and then pass them into an afterburner for direct combustion, using the heat from the mixture to preheat the feed. However, this method has the following significant drawbacks:

[0004] Waste of energy grade: The valuable chemical energy (H2, CO) contained in the anode exhaust gas is only used in the form of combustion heat at a low grade, and its value is not fully realized (see the discussion on waste heat grade utilization in patent CN105841396B).

[0005] Pollutant generation: High-temperature combustion produces thermal nitrogen oxides (NOx), causing environmental pollution (with the problem of low nitrogen emissions).

[0006] Poor system flexibility: Simple combustion heat release is difficult to match and adjust flexibly and efficiently with cold and hot loads (see the discussion of operation priority control in patent CN107387259B).

[0007] While some existing technologies (such as patent CN114583231B) propose partial recirculation or refrigeration of fuel cell exhaust gas, these are mostly concentrated in proton exchange membrane fuel cells (PEMFCs) or automotive applications, and their exhaust gas temperature and composition differ significantly from those of SOFCs. For high-temperature SOFC exhaust gas, particularly how to combine recirculation with deep waste heat utilization and catalytic clean combustion, and integrate it into a fixed distributed combined cooling, heating, and power (CCHP) system, there is a lack of systematic optimization design, making it difficult to simultaneously achieve ultra-high efficiency, near-zero emissions, and intelligent control. Therefore, researching how to optimize the system structure to improve system operating efficiency, achieve near-zero emissions, and enhance system control intelligence is of great significance. Summary of the Invention

[0008] In view of this, the present invention aims to propose a SOFC combined cooling, heating, and power system and method for anode tail gas recovery and combined tail gas combustion, in order to solve the problems existing in the conventional SOFC operation where the high-quality chemical energy of the anode tail gas is simply burned, resulting in energy waste and a bottleneck in the overall system efficiency; the problem that conventional combustion of anode tail gas easily produces thermal NOx due to the high-temperature flame zone, which does not meet stringent environmental protection requirements; the problem that SOFC stacks are sensitive to fuel concentration and temperature fluctuations, affecting long-term stable operation; and the problem that existing combined cooling, heating, and power systems lack the dynamic coupling and regulation capabilities for multiple user loads (cooling, heating, and electricity). This invention aims to optimize the system structure, achieve anode tail gas diversion and intelligent circulation, ensure catalytic combustion synergistic treatment, realize a multi-grade energy cascade recovery system, and realize an intelligent collaborative control system.

[0009] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0010] The present invention relates to an SOFC combined cooling, heating and power system and method for anode exhaust gas recovery and exhaust gas combustion, wherein the SOFC combined cooling, heating and power system includes an SOFC power generation module, an input system, and an exhaust gas treatment and energy recovery module; the SOFC power generation module is connected to or disconnected from the input system and the exhaust gas treatment and energy recovery module respectively.

[0011] Furthermore, the SOFC power generation module includes an SOFC stack, a gas-to-gas heat exchanger, and a circulating fan; the SOFC stack is connected to or disconnected from the input system through the gas-to-gas heat exchanger, and the SOFC stack is connected to or disconnected from the exhaust gas treatment and energy recovery module through the circulating fan; the SOFC stack is connected to or disconnected from the exhaust gas treatment and energy recovery module.

[0012] Furthermore, the SOFC power generation module also includes a mixer; the two ends of the mixer are connected to or disconnected from the SOFC stack and the circulating fan, respectively.

[0013] Furthermore, the SOFC power generation module also includes a diversion three-way valve V1; the input end of the diversion three-way valve V1 is connected to the SOFC stack, and the output end of the diversion three-way valve V1 is connected to or shut off the circulating fan, the exhaust gas treatment and energy recovery module, respectively.

[0014] Furthermore, the SOFC power generation module also includes an AC power output device and a DC / AC converter; the DC power generated by the SOFC stack is connected to the AC power output device through the DC / AC converter.

[0015] Furthermore, the SOFC stack includes an anode inlet and a cathode inlet; the anode inlet is connected to or disconnected from the gas output terminal of the mixer; the cathode inlet is connected to or disconnected from the gas output terminal of the gas-to-gas heat exchanger.

[0016] Furthermore, the exhaust gas treatment and energy recovery module includes a catalytic combustion chamber, a waste heat boiler, an absorption chiller, and a chimney; the catalytic combustion chamber is connected to or shut off at one end of the chimney via the waste heat boiler and the absorption chiller in sequence; the other end of the chimney is connected to the catalytic combustion chamber.

[0017] Furthermore, the absorption chiller is a lithium bromide unit.

[0018] Furthermore, the catalytic combustion chamber includes a fuel / oxidant mixing zone, a catalyst bed, and high-temperature clean flue gas; the fuel / oxidant mixing zone is connected to or shut off from the waste heat boiler via the catalyst bed and high-temperature clean flue gas in sequence.

[0019] A method for anode tail gas recovery combined with tail gas combustion SOFC combined cooling, heating and power system, the method being applied to the aforementioned anode tail gas recovery combined with tail gas combustion SOFC combined cooling, heating and power system, the method comprising the following steps:

[0020] Step 1: Fresh fuel is mixed with reflux gas from the anode exhaust gas recirculation loop and then preheated by a gas-to-gas heat exchanger before entering the anode inlet of the SOFC stack; fresh air is preheated by a gas-to-gas heat exchanger before entering the cathode inlet of the SOFC stack.

[0021] Step 2: After the SOFC stack generates electricity, a portion of the anode tail gas is recycled back; the remaining anode tail gas and the oxygen-deficient tail gas discharged from the cathode enter the catalytic combustion chamber together.

[0022] Step 3: Low-temperature flameless combustion occurs under the action of a catalyst, completely eliminating unburned fuel and converting chemical energy into thermal energy; the generated high-temperature flue gas first enters the waste heat boiler to generate thermal energy, and then enters the absorption chiller to drive the refrigeration cycle to generate cold energy, thereby realizing the joint supply of three energy products: cold, heat and electricity.

[0023] Compared with the prior art, the SOFC combined cooling, heating and power system and method with anode tail gas recovery and tail gas combustion described in this invention have the following advantages:

[0024] The system described above optimizes the system structure, enabling anode tail gas diversion and intelligent circulation, ensuring synergistic treatment by catalytic combustion, realizing a multi-grade energy cascade recovery system, and achieving an intelligent collaborative control system. Furthermore, the system in this application aims to address the problems of chemical energy waste in SOFC anode tail gas, pollutant generation from tail gas combustion, and insufficient system flexibility. Through innovative diversion and recovery, catalytic combustion, and cascade utilization technologies, it achieves deep utilization of fuel and efficient energy recovery, ultimately significantly improving the overall primary energy efficiency of the system, achieving clean emissions, and enhancing load adaptability. Attached Figure Description

[0025] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the system structure.

[0027] Figure 2 This is a schematic diagram of the overall system structure;

[0028] Figure 3 This is a flowchart illustrating the application of the system in Example 1;

[0029] Figure 4 This is a flowchart illustrating the application of the system in Example 2;

[0030] Figure 5 This is a flowchart illustrating the application of the system in Example 3;

[0031] Figure 6 This is a flowchart illustrating the application of the system in Example 4;

[0032] Figure 7 This is a flowchart illustrating the application of the system in Example 5.

[0033] Figure reference numerals: 10, SOFC power generation module; 101, mixer; 102, AC power output device; 103, DC / AC converter; 11, input system; 12, exhaust gas treatment and energy recovery module; 1, SOFC stack; 2, gas-to-gas heat exchanger; 3, circulating fan; 4, catalytic combustion chamber; 41, fuel / oxidant mixing zone; 42, catalyst bed; 43, high-temperature clean flue gas; 5, waste heat boiler; 51, hot water / steam output; 6, absorption chiller; 61, chilled water output; 7, chimney; 8, main control system; 9, regulating valve. Detailed Implementation

[0034] The inventive concepts of this disclosure will be described below using terminology commonly used by those skilled in the art to communicate the essence of their work to others skilled in the art. However, these inventive concepts may be embodied in many different forms and should not be construed as limited to the embodiments described herein.

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] To address the problems in existing SOFC technologies, such as the simple combustion of high-quality chemical energy from anode exhaust gas leading to energy waste and bottlenecks in overall system efficiency; the tendency of conventional combustion of anode exhaust gas to generate thermal NOx in the high-temperature flame zone, failing to meet stringent environmental protection requirements; the sensitivity of SOFC stacks to fuel concentration and temperature fluctuations affecting long-term stable operation; and the insufficient dynamic coupling and regulation capabilities of existing combined cooling, heating, and power (CCHP) systems for multiple user loads (cooling, heating, and electricity), this embodiment proposes an SOFC CCHP system and method with anode exhaust gas recovery and combined exhaust gas combustion. This system relates to a solid oxide fuel cell (SOFC) based CCHP system, specifically a system integration method that achieves efficient and clean CCHP by synergistically recovering and catalytically combusting SOFC anode and cathode exhaust gases. The system includes an SOFC power generation module 10, an input system 11, and an exhaust gas treatment and energy recovery module 12. The SOFC power generation module 10 is connected to or disconnected from the input system 11 and the exhaust gas treatment and energy recovery module 12, respectively.

[0038] The system configuration optimizes its structure, enabling anode tail gas diversion and intelligent circulation to ensure synergistic catalytic combustion treatment; it also facilitates multi-grade energy cascade recovery and intelligent collaborative control. Specifically, the proposed and configured anode tail gas diversion and recirculation system precisely adjusts the recirculation ratio using intelligent control valves (such as three-way valves), improving fuel utilization and stabilizing the inlet conditions of the SOFC stack 1. The constructed high-efficiency energy cascade utilization chain of "power generation → high-temperature flue gas heating → medium-temperature flue gas cooling," coupled with the waste heat boiler 5 and the lithium bromide absorption chiller 6, maximizes energy recovery. Furthermore, based on real-time user-side cooling, heating, and electrical load demands, intelligent algorithms dynamically adjust the tail gas recirculation ratio, catalytic combustion load, and working fluid flow rate to achieve efficient and optimized operation across all system conditions. In addition, the system in this application aims to solve the problems of chemical energy waste in the anode tail gas of SOFC stack 1, pollutant generation from tail gas combustion, and insufficient system flexibility. Through innovative diversion and recovery, catalytic combustion and cascade utilization technologies, it achieves deep utilization of fuel and efficient energy recovery, ultimately significantly improving the overall primary energy efficiency of the system, achieving clean emissions and enhancing load adaptability.

[0039] The SOFC power generation module 10 includes an SOFC stack 1, a gas-to-gas heat exchanger 2, and a circulating fan 3. The SOFC stack 1 is connected to or disconnected from the input system 11 through the gas-to-gas heat exchanger 2, and the SOFC stack 1 is connected to or disconnected from the exhaust gas treatment and energy recovery module 12 through the circulating fan 3; the SOFC stack 1 is connected to or disconnected from the exhaust gas treatment and energy recovery module 12.

[0040] By coordinating the components within the SOFC power generation module 10, the overall stability and reliability of the power supply can be effectively improved. Furthermore, through the circulating fan 3 and the exhaust gas treatment and energy recovery module 12, near-zero carbon emissions can be achieved, enhancing environmental protection. When the SOFC stack 1 is directly connected to the exhaust gas treatment and energy recovery module 12, the high-temperature cathode exhaust gas generated in the SOFC stack 1 can be directly connected to or disconnected from the exhaust gas treatment and energy recovery module 12. This high-temperature cathode exhaust gas is oxygen-deficient and contains unreacted oxygen (O2).

[0041] Preferably, the SOFC stack 1 includes an anode inlet and a cathode inlet. An electrochemical reaction occurs between the fuel entering through the anode inlet and the fuel entering through the cathode inlet. The anode inlet is connected to or disconnected from the gas output terminal of the mixer 101. The cathode inlet is connected to or disconnected from the gas output terminal of the gas-to-gas heat exchanger 2. Specifically, the anode outlet of the SOFC stack 1 is divided into two paths via pipelines: the first path connects to the inlet of the anode exhaust gas recirculation device (such as a circulating fan), and the outlet of this device is mixed with the fresh fuel intake pipe and then connected to the low-temperature fuel channel of the gas-to-gas heat exchanger 2, ultimately returning to the anode inlet of the SOFC stack 1, forming an anode exhaust gas recirculation loop; the second path connects to the fuel inlet of the catalytic combustion chamber 4. The cathode outlet of the SOFC stack 1 is connected to the low-temperature air channel of the gas-to-gas heat exchanger 2 via pipelines, preheats the fresh air, and then connects to the combustion-supporting gas inlet of the catalytic combustion chamber 4.

[0042] By coordinating the anode and cathode inlets in SOFC stack 1, the power generation stability and continuity of SOFC stack 1 can be effectively guaranteed. Furthermore, by synergistically treating the anode exhaust gas (fuel) and cathode exhaust gas (oxidant) in a single catalytic combustion chamber 4, low-temperature, high-efficiency, and flameless combustion is achieved, suppressing NOx formation at the source.

[0043] The SOFC power generation module 10 also includes a mixer 101. The two ends of the mixer 101 are connected to or disconnected from the SOFC stack 1 and the circulating fan 3, respectively, to enable the mild fuel gas to be sent into the SOFC stack 1 through the circulating fan 3.

[0044] The SOFC power generation module 10 also includes a diversion three-way valve V1. The input end of the diversion three-way valve V1 is connected to the SOFC stack 1, and the output end of the diversion three-way valve V1 is connected to or shut off the circulating fan 3 and the exhaust gas treatment and energy recovery module 12, respectively.

[0045] By connecting the three-way valve V1 to the SOFC stack 1, the high-temperature anode exhaust gas generated during the DC power generation process in the SOFC stack 1 can be transported to the exhaust gas treatment and energy recovery module 12 through the three-way valve V1 to achieve exhaust gas recycling. The high-temperature anode exhaust gas is rich in H2 and CO, which can provide combustion fuel for the exhaust gas treatment and energy recovery module 12.

[0046] The SOFC power generation module 10 also includes an AC power output device 102 and a DC / AC converter 103. The DC power generated by the SOFC stack 1 is connected to the AC power output device 102 through the DC / AC converter 103.

[0047] By cooperating with the AC power output device 102 and the DC / AC converter 103, the DC power generated by the SOFC stack 1 can be stably output to the power system, thereby improving the safety and reliability of the system.

[0048] The input system 11 includes fresh fuel and fresh air. The fresh fuel and fresh air are arranged in parallel in the input system 11. The input system 11 controls the connection of the fresh fuel and fresh air to the SOFC stack 1 as needed, generating corresponding gases that enter the gas-to-gas heat exchanger 2, thereby realizing the energy cycle between the different input systems 11 and the SOFC power generation module 10.

[0049] The exhaust gas treatment and energy recovery module 12 includes a catalytic combustion chamber 4, a waste heat boiler 5, an absorption chiller 6, and a chimney 7. The catalytic combustion chamber 4 is connected to or disconnected from one end of the chimney 7 via the waste heat boiler 5 and the absorption chiller 6. The other end of the chimney 7 is connected to the catalytic combustion chamber 4. The absorption chiller 6 is a lithium bromide unit. The waste heat boiler 5 can produce steam or hot water for heating; the absorption chiller 6 is driven by the heat source generated by the waste heat boiler 5 or directly diverted high-temperature flue gas to produce chilled water for cooling.

[0050] By coordinating the catalytic combustion chamber 4, waste heat boiler 5, absorption chiller 6, and chimney 7, near-zero pollutant emissions can be achieved. Catalytic combustion avoids the high-temperature flame zone, suppressing the formation of thermal NOx at its source, resulting in clean flue gas and significant environmental benefits. It also enhances system stability; the anode tail gas recirculation dilutes the inlet fuel concentration, helping to slow carbon deposition and stabilize the stack operating temperature, extending system lifespan. Furthermore, it enables multi-functional output, improving system operational flexibility; it can simultaneously provide users with the necessary electricity, heating / hot water, and air conditioning / cooling, and its intelligent control system flexibly adapts to diverse and dynamically changing energy demands, making it suitable for a wide range of applications.

[0051] The catalytic combustion chamber 4 includes a fuel / oxidant mixing zone 41, a catalyst bed 42, and a high-temperature clean flue gas 43. The fuel / oxidant mixing zone 41 is connected to or shut off from the waste heat boiler 5 via the catalyst bed 42 and the high-temperature clean flue gas 43. The catalyst bed 42 contains Pt, Pd, or perovskite. The high-temperature clean flue gas 43 has a temperature of 650°C and is low in NOx. The catalytic combustion chamber 4 is filled with a precious metal (including Pt or Pd) or transition metal oxide catalyst. The high-temperature flue gas outlet of the catalytic combustion chamber 4 is connected to the generator of the waste heat boiler 5 and the absorption chiller 6 in sequence, and finally, the low-temperature flue gas is discharged through the chimney 7.

[0052] By setting the catalytic combustion chamber 4 in the system, the flexibility of system operation can be effectively improved, the stable and reliable operation of the system can be ensured, and the combustion efficiency of energy in the system can be significantly improved. By reflux of anode exhaust gas, the fuel utilization rate is improved. By using high-quality flue gas in stages (power generation → heating → cooling), the comprehensive utilization rate of primary energy of the system is increased from 70-80% in the traditional way to more than 90%.

[0053] The waste heat boiler 5 includes a hot water / steam output 51. The hot water / steam output 51 is used to supply heat to the system. The waste heat boiler 5 transmits the output cooled flue gas to the input end of the absorption chiller 6. The temperature range of the cooled flue gas is 150℃-200℃.

[0054] The absorption chiller 6 includes a chilled water output 61. The chilled water output 61 is used to supply cooling to the system. The absorption chiller 6 transmits the output low-temperature exhaust gas to the chimney 7, through which the low-temperature exhaust gas re-enters the catalytic combustion chamber 4, thereby achieving exhaust gas recovery.

[0055] Through the arrangement of the components within the system, the core of the system lies in the efficient, graded, and clean recovery and utilization of the high-temperature, fuel-rich anode exhaust gas generated by solid oxide fuel cells (SOFCs). It also effectively solves the problem of energy waste and system efficiency bottlenecks caused by the simple combustion of high-quality chemical energy in the anode exhaust gas during traditional SOFC operation; addresses the issue that conventional combustion methods for anode exhaust gas easily generate thermal NOx in the high-temperature flame zone, failing to meet stringent environmental protection requirements; resolves the problem of SOFC stack 1 being sensitive to fuel concentration and temperature fluctuations, affecting long-term stable operation; and addresses the insufficient dynamic coupling and regulation capabilities of existing combined cooling, heating, and power (CCHP) systems for diverse user loads (cooling, heating, and electricity).

[0056] The specific workflow is as follows:

[0057] A portion of the high-temperature anode exhaust gas is mixed with fresh fuel and then recycled back to the SOFC inlet, significantly improving fuel utilization and stack operational stability. Another portion of the hydrogen-rich exhaust gas is introduced together with the oxygen-deficient cathode exhaust gas into a specially designed catalytic combustion chamber 4, achieving low-temperature, flameless, and completely clean combustion. The high-temperature flue gas generated from combustion then passes sequentially through a waste heat boiler 5 and an absorption chiller 6 to produce steam / hot water and chilled water, respectively, ultimately achieving combined power, heat, and cooling. This invention significantly improves the system's primary energy utilization efficiency (up to 90% or more) and achieves near-zero pollutant emissions through "graded recovery and cascaded utilization" of exhaust gas energy and materials, and "source control" of pollutants.

[0058] The system also includes a main control system 8, which is used to monitor the status of any one of the following modules in real time: SOFC power generation module 10, input system 11, and exhaust gas treatment and energy recovery module 12. The system also includes regulating valves 9. Regulating valves 9 are installed in the system. At least one regulating valve 9 is provided. These are used to enable the connection and disconnection between different components within the system.

[0059] The main control system 8 is configured to receive user-side cold, heat, and electrical load signals, as well as temperature, pressure, and flow signals from key system nodes. It then outputs control commands to the actuators to dynamically adjust the exhaust gas recirculation ratio and energy distribution proportion. Key nodes include the outlet of the SOFC stack 1 and / or the inlet of the catalytic combustion chamber 4. Actuators include the control valve of the anode exhaust gas recirculation device or the inlet regulating valve of the catalytic combustion chamber 4.

[0060] A method for anode tail gas recovery combined with tail gas combustion SOFC combined cooling, heating and power system, the method being applied to the aforementioned anode tail gas recovery combined with tail gas combustion SOFC combined cooling, heating and power system, the method comprising the following steps:

[0061] Step 1: Fresh fuel is mixed with return gas from the anode exhaust gas recirculation loop and preheated by gas-to-gas heat exchanger 2 before entering the anode inlet of SOFC stack 1. Fresh air is preheated by gas-to-gas heat exchanger 2 before entering the cathode inlet of SOFC stack 1.

[0062] Step 2: After generating electricity from SOFC stack 1, a portion of the anode exhaust gas is recycled to improve fuel concentration and system stability. The remaining anode exhaust gas, along with the oxygen-deficient exhaust gas from the cathode, enters catalytic combustion chamber 4.

[0063] Step 3: Low-temperature flameless combustion occurs under the action of a catalyst, completely eliminating unburned fuel and converting chemical energy into heat energy. The resulting high-temperature flue gas first enters the waste heat boiler 5 to generate heat energy, and then enters the absorption chiller 6 to drive a refrigeration cycle to generate cold energy, thereby achieving the combined supply of three energy products: cold, heat, and electricity. The control system 8 intelligently adjusts the operating strategy according to real-time demand by regulating valves 9.

[0064] The anode exhaust gas is precisely diverted via a controllable regulating valve 9, with a portion flowing back to the inlet and the other portion entering the catalytic combustion chamber 4. The recirculation ratio can be intelligently adjusted according to operating conditions, balancing efficient fuel utilization, stable stack operation, and subsequent energy recovery. This effectively achieves exhaust gas diversion and intelligent circulation control. By using the anode exhaust gas of the SOFC stack 1 as fuel and the cathode exhaust gas as oxidant, both are fed into the catalytic combustion chamber 4 for reaction, achieving clean, efficient, and low-temperature synergistic treatment of the two exhaust gases. This fundamentally reduces Ox generation and achieves synergistic catalytic combustion. Furthermore, the system integrates an intelligent main control system 8, which dynamically optimizes the exhaust gas recirculation ratio, catalytic combustion intensity, and heat / cold output ratio based on real-time cold, heat, and electrical loads. This enables on-demand energy allocation and optimal system operation, achieving intelligent energy management based on load demand.

[0065] Example 1: Baseline Power System for Data Centers

[0066] Data centers are typical scenarios with high power load, high cooling load, and low heat load, placing extremely high demands on the reliability and efficiency of energy supply. This embodiment uses a 500kW SOFC stack 1 as the core power source. The system has a high anode tail gas recirculation ratio (70%), meaning that most of the unreacted fuel is recycled, greatly improving fuel economy and stack operational stability. A small amount of hydrogen-rich residual anode tail gas and cathode tail gas enter the catalytic combustion chamber 4, where they undergo complete clean combustion at 650°C under the action of a Pt-based catalyst. The resulting high-temperature flue gas first flows through a waste heat boiler 5, producing 0.8MPa saturated steam. This steam is not directly used for heating (data centers have low heat demand), but rather as a heat source to drive a lithium bromide absorption chiller, producing chilled water at approximately 20°C to provide the cooling capacity required for precision air conditioning in the server room, with a cooling capacity of 200 refrigeration tons (RT). The integrated main control system monitors the data center's IT load and server room temperature in real time, dynamically fine-tuning the exhaust gas return valve V1 and flue gas distribution valve V2 to ensure the system operates in its most efficient range under any load. Actual operation tests show that the system's power generation efficiency reaches 55%, and its overall energy efficiency is an astonishing 92%, with NOx emission concentrations in the flue gas below 5 mg / m³, far exceeding the most stringent environmental standards.

[0067] Example 2: Case Study of a Green Agricultural Park Using Biogas as Fuel

[0068] This embodiment demonstrates the system's excellent fuel adaptability. Using a large green agricultural park as an example, the fuel comes from biogas (mainly CH4 and CO2, with a small amount of H2S) produced by anaerobic fermentation of livestock manure, straw, and other waste within the park. The core structure of the system is the same as in Embodiment 1, but a pre-desulfurization device is added before fresh fuel enters the system to prevent sulfides from poisoning and deactivating the SOFC electrodes and downstream catalysts. The catalytic combustion chamber 4 uses a perovskite-type catalyst (such as LaSrMnO3) with better sulfur resistance, replacing the precious metal Pt catalyst to reduce long-term operating costs and maintenance frequency. This system achieves energy self-sufficiency for the park: the electricity generated by the SOFC meets the park's office, production, and lighting needs; the hot water generated by the waste heat boiler 5 is used for winter heating in the greenhouse and insulation of the anaerobic fermentation tanks; and the cold energy generated by the absorption chiller 6 is used in the park's cold chain logistics center (refrigeration and freezing). This case perfectly combines waste treatment (environmental protection) with energy production (economy). According to calculations, the annual primary energy saving rate exceeds 35%, achieving a significant win-win situation in both ecological and economic benefits.

[0069] Example 3: Remote microgrid energy station coupled with photovoltaic power

[0070] This embodiment targets remote areas or islands without reliable mains grid coverage. The system constructs an off-grid microgrid primarily powered by renewable energy. During the day, the system relies mainly on photovoltaic (PV) power plants to meet all electricity demands. At this time, the SOFC system operates in low-power standby mode, maintaining the most basic baseload. Simultaneously, surplus PV power is used for water electrolysis to produce hydrogen (electrolyzer not shown in the diagram), storing the energy as green hydrogen. At night, on cloudy days, or when PV output is insufficient, the SOFC system increases its operating power and blends with, or even uses entirely, the green hydrogen produced during the day as fuel, continuously and stably outputting electricity. The value of this system lies in its extremely high power generation efficiency, flexible fuel adaptability (rapid switching between natural gas and hydrogen), and powerful combined heat and power (CHP) capabilities. It perfectly compensates for the intermittency and instability of PV power generation, becoming an indispensable and dispatchable core baseload energy unit in the microgrid, achieving a reliable energy supply 24 / 7 throughout the year.

[0071] Example 4: High Cooling Load Operation Mode in Summer

[0072] This embodiment is not a standalone application, but rather demonstrates a refined operating strategy for the system during a specific season (summer). During this period, there is almost no heating demand on the user side, but the demand for air conditioning reaches its peak. Based on this, the main control system 8 executes a summer mode strategy: First, it appropriately reduces the anode exhaust gas recirculation ratio (e.g., from 70% to 50%), meaning that more fuel-rich exhaust gas is sent to the catalytic combustion chamber 4, thereby increasing the total amount of available high-temperature flue gas, i.e., increasing the "fuel" to drive the chiller. Second, the control system adjusts the flue gas distribution valve (V2) so that as much of the high-temperature flue gas generated by catalytic combustion as possible flows directly to the generator of the absorption chiller 6, maximizing the production of chilled water. The flue gas flowing through the waste heat boiler 5 is only used to produce a small amount of domestic hot water or bypassed. Through this dynamic adjustment of the "heat-to-power ratio," the system can direct the vast majority of energy output towards "electricity" and "cooling," perfectly matching the summer load characteristics and achieving optimal seasonal energy efficiency.

[0073] Example 5: High Heating Load Operation Mode in Winter

[0074] Corresponding to Example 4, this example demonstrates the system's operating strategy under winter conditions. At this time, the user's demand for heating hot water is huge, while the demand for cooling is zero. The main control system 8 switches to winter mode: First, it increases the anode exhaust gas recirculation ratio (e.g., to 80%), meaning that most of the fuel is recycled within the fuel cell stack. Although the amount of fuel entering the catalytic combustion chamber 4 decreases, the overall "thermal-to-electricity ratio" of the system increases, i.e., it focuses more on "heat" output. Second, the control system adjusts the flue gas distribution valve (V2) so that all the high-temperature flue gas generated by catalytic combustion preferentially flows through the waste heat boiler 5 to produce a large amount of high-temperature hot water or steam for the heating system. The path to the absorption chiller 6 is completely closed. Through this mode, the system focuses its energy output entirely on "electricity" and "heat" to meet the winter load demand, again demonstrating the system's intelligent and flexible load adaptability.

[0075] Through the application of the system in Examples 1-5, it is clear that efficient and clean distributed energy is the core of the future energy system. This system is particularly suitable for applications with extremely high requirements for energy quality, reliability, and environmental protection, such as data centers, hospitals, high-end manufacturing parks, green buildings, and energy stations in remote areas, with huge market potential. It can also be developed into a modular, containerized integrated energy station, facilitating rapid deployment and expansion. When combined with renewable energy sources such as wind power and photovoltaics, it can utilize the generated green hydrogen as fuel to construct a zero-carbon smart energy system. Furthermore, it can generate any one of the potential benefits in terms of economic, environmental, and social benefits. Specifically, economic benefits include: a primary energy utilization rate exceeding 90%, far higher than traditional distributed energy systems (~50%) and ordinary gas-fired combined heat and power systems (~80%), significantly reducing user energy costs and shortening the investment payback period. Environmental benefits include: near-zero emissions of pollutants (NOx, SOx, dust), and a significant reduction in CO2 emissions due to extremely high efficiency, demonstrating outstanding environmental advantages. The social benefits include: enhancing regional power supply reliability, alleviating peak-valley pressure on the power grid, and serving as a key distributed technology for building a new power system and achieving a cleaner and lower-carbon energy structure.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A SOFC (Solar-Fuel Combined Heat and Power) system with anode tail gas recovery and tail gas combustion, characterized in that, It includes an SOFC power generation module (10), an input system (11), and an exhaust gas treatment and energy recovery module (12); the SOFC power generation module (10) is connected to or disconnected from the input system (11) and the exhaust gas treatment and energy recovery module (12), respectively.

2. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 1, characterized in that, The SOFC power generation module (10) includes an SOFC stack (1), a gas-to-gas heat exchanger (2), and a circulating fan (3); the SOFC stack (1) is connected to or disconnected from the input system (11) through the gas-to-gas heat exchanger (2), and the SOFC stack (1) is connected to or disconnected from the exhaust gas treatment and energy recovery module (12) through the circulating fan (3); the SOFC stack (1) is connected to or disconnected from the exhaust gas treatment and energy recovery module (12).

3. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 2, characterized in that, The SOFC power generation module (10) also includes a mixer (101); the two ends of the mixer (101) are connected to or disconnected from the SOFC stack (1) and the circulating fan (3), respectively.

4. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 2, characterized in that, The SOFC power generation module (10) also includes a diversion three-way valve V1; the input end of the diversion three-way valve V1 is connected to the SOFC stack (1), and the output end of the diversion three-way valve V1 is connected to or shut off the circulating fan (3) and the exhaust gas treatment and energy recovery module (12).

5. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 2, characterized in that, The SOFC power generation module (10) also includes an AC power output device (102) and a DC / AC converter (103); the DC power generated by the SOFC stack (1) is connected to the AC power output device (102) through the DC / AC converter (103).

6. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 3, characterized in that, The SOFC stack (1) includes an anode inlet and a cathode inlet; the anode inlet is connected to or disconnected from the gas output terminal of the mixer (101); the cathode inlet is connected to or disconnected from the gas output terminal of the gas-to-gas heat exchanger (2).

7. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 1, characterized in that, The exhaust gas treatment and energy recovery module (12) includes a catalytic combustion chamber (4), a waste heat boiler (5), an absorption chiller (6), and a chimney (7); the catalytic combustion chamber (4) is connected to or shut off one end of the chimney (7) in sequence through the waste heat boiler (5), the absorption chiller (6); and the other end of the chimney (7) is connected to the catalytic combustion chamber (4).

8. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 7, characterized in that, The absorption chiller (6) is a lithium bromide unit.

9. The SOFC combined cooling, heating, and power system with anode tail gas recovery and tail gas combustion according to claim 7, characterized in that, The catalytic combustion chamber (4) includes a fuel / oxidant mixing zone (41), a catalyst bed (42), and high-temperature clean flue gas (43); the fuel / oxidant mixing zone (41) is connected to or shut off from the waste heat boiler (5) in sequence through the catalyst bed (42) and the high-temperature clean flue gas (43).

10. A method for SOFC (Solar-Fuel Combined Heat and Power) system with anode tail gas recovery and tail gas combustion, characterized in that, The method is applied to a SOFC (Solar-Cooling, Heating and Power) system with anode tail gas recovery and tail gas combustion as described in any one of claims 1-9, and the method includes the following steps: Step 1: Fresh fuel is mixed with the return gas from the anode exhaust gas recirculation loop and then preheated by the gas-to-gas heat exchanger (2) before entering the anode inlet of the SOFC stack (1); fresh air is preheated by the gas-to-gas heat exchanger (2) before entering the cathode inlet of the SOFC stack (1). Step 2: After generating electricity through the SOFC stack (1), a portion of the anode tail gas is recycled back; the remaining anode tail gas and the oxygen-deficient tail gas discharged from the cathode enter the catalytic combustion chamber (4) together. Step 3: Low-temperature flameless combustion occurs under the action of a catalyst, completely eliminating unburned fuel and converting chemical energy into thermal energy; the generated high-temperature flue gas first enters the waste heat boiler (5) to generate thermal energy, and then enters the absorption chiller (6) to drive the refrigeration cycle to generate cold energy, thereby realizing the joint supply of three energy products: cold, heat and electricity.

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