| Against the backdrop of China’s current annual carbon dioxide emissions being the highest in the world,achieving both the peak of carbon emissions by 2030 and carbon neutrality by 2060 is an extremely challenging task.To increase the proportion of renewable energy in primary energy consumption and enhance the efficient utilization of clean and low-carbon energy,hydrogen energy is a key move.In contrast to electricity,a process-based secondary energy source that is not readily storable,hydrogen energy is a clean and storable secondary energy carrier that can be sourced from diverse compounds,including water,methanol,methane,and others.The efficient coupling of hydrogen energy and electricity through solid oxide fuel cell(SOFC)is instrumental in enabling high-efficiency,clean conversion,regulation,and large-scale storage and integration of various forms of energy,thereby having significant implications for the construction of a novel energy system for future society.In response to the"dual carbon"challenge,this thesis proposes a novel technological pathway for hydrogen-electric coupling based on SOFC,and investigates the characteristics of three representative hydrogen-electric coupling types,namely pure hydrogen-electric coupling,methanol’s hydrogen and electricity coupling,and hydrogen of low-concentration gas and electricity coupling.The specific research content is as follows:The characteristics of pure hydrogen-electric coupling were analyzed by studying the hydrogen-electric coupling process of SOFC using pure hydrogen gas as the fuel.A two-dimensional computational model was established,taking into account the coupling processes of multiple physical fields,such as electrochemistry,fluid mechanics,and thermodynamics.The study indicates that low operating voltage and high operating temperature have a promoting effect on electrochemical reactions.High fuel flow rate has a positive effect on cell cooling,while increasing the length of the cell is not conducive to improving power performance.Overall,the following operating conditions are relatively reasonable:an operating voltage of 0.6 V,an operating temperature of 800°C,a fuel flow rate of 1.0 m/s,and a cell length of 10 mm.The analysis verifies the feasibility of pure hydrogen-electric coupling technology based on SOFC.The characteristics of methanol’s hydrogen and electricity coupling were investigated by analyzing the hydrogen-electric coupling process using methanol,the simplest alcohol with a high hydrogen-to-carbon ratio,as the fuel.The results show that the maximum power density of methanol-SOFC is close to that of pure hydrogen-SOFC at 800°C.Methanol-SOFC reaches a thermal equilibrium state at a voltage of 0.7 V.A thicker anode thickness and a temperature of 750°C have a positive contribution to power generation and thermal equilibrium.So,the feasibility of methanol-hydrogen-electric coupling technology based on SOFC was verified.The characteristics of hydrogen of low-concentration gas and electricity coupling were explored,and an innovative approach with ultra-low concentration gas and direct dry-reforming carbon dioxide was proposed.Studies have shown that the maximum power density at 800°C is 0.28 W/cm~2,the working voltage of 0.8 V can make the cell reach a thermal equilibrium state,the working temperature has a significant impact on the dry reforming reaction for hydrogen production.Furthermore,a 200μm anode is sufficient to sustain high power generation performance.T he industrial scale-up economies can reach nearly 100 billion yuan.Thus,the feasibility of hydrogen of low-concentration gas and electricity coupling via SOFC was further verified. |
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