基于钙基CO2载体的生物质气化制氢和储能耦合体系基础研究

A novel system coupling steam gasification of biomass for H2 production and CaO/Ca(OH)2 based on calcium-based CO2 sorbent is proposed, in order to solve the problems of reutilization of spent CO2 sorbent discharged from H2 production and high energy consumption in production of steam as gasification agent, which can realize H2 production, CO2 capture and energy storage. In this project, the hydration/dehydration performances and the mechanical properties of the various calcium-based CO2 sorbents experienced H2 production/carbonation-calcination cycles will be investigated. And the catalysis for H2 production of biomass and CO2 capture behavior of the calcium-based CO2 sorbent experienced hydration/dehydration cycles for energy storage will be researched. The interactive effect of H2 production process and energy storage process will be revealed. The inactivation mechanism of H2 production/CO2 capture performances and hydration/dehydration behaviors of calcium-based CO2 sorbents in the coupling system will be discussed. In addition, the improvement in the performances of calcium-based sorbents and change of the particle structures of the sorbents will be revealed. The controllable and functional design of calcium-based synthetic CO2 sorbents will be developed to realize effective H2 production, CO2 capture and energy storage. Match, coupling and regulation of biomass gasification for H2 production and CaO/Ca(OH)2 energy storage will be studied, in order to reinforce each other between H2 hydration/CO2 capture and energy storage. The above research will lay a theoretical foundation to establish the novel, efficient and low cost renewable energy route.

提出基于钙基CO2载体的生物质气化制氢和CaO/Ca(OH)2储能耦合新体系，同时解决制氢中排出失活钙基CO2载体的再利用问题和水蒸气能耗高的问题，形成具有制氢、碳捕集和储能耦合的新工艺。研究多类型钙基CO2载体经历制氢/脱碳-再生循环后的水合/脱水储能特性、颗粒机械性能，探讨钙基CO2载体经历水合/脱水储能循环后的催化生物质制氢和脱碳特性，揭示制氢过程与储能过程的相互作用机制，阐明在两个耦合过程中钙基CO2载体的制氢/脱碳性能和放热/储热性能失活机理以及活化调控机制、颗粒结构演变机理，对钙基复合CO2载体进行功能化可控设计，实现同时高效催化制氢、脱碳和储能，研究基于钙基CO2载体的生物质气化制氢和CaO/Ca(OH)2储能的匹配、耦合及调控，使制氢/脱碳过程与储能过程之间形成相互促进的格局；为构建新型高效、低成本可再生能源工艺路线奠定理论基础。

该项目提出了基于钙基CO2载体的生物质气化制氢和太阳能热化学储能耦合的新型可再生能源系统，围绕该系统开展了以下研究：从微观原子分子层面阐明了钙铈CO2载体促进生物质气化过程中水气变换反应制氢机制，明确了CO2载体中Ce-O键的形成是其高效捕集CO2的关键，揭示了惰性支撑体和催化剂对钙基CO2载体在生物质气化制氢中的协同促进机理，阐明了复合钙基CO2载体高温抗烧结和抗积碳机理，明晰了复合钙基CO2载体作用下生物质/废塑料在热解、气化制氢中的转化和反应路径。创制了高活性赤泥修饰钙铈CO2载体，探明了CO2载体性能和氧空位/表面吸附氧浓度之间的构效关系，10次循环后合成气中H2浓度与产量分别达到69.1vol.%与652.4mL/g。设计合成了微米管状Fe/Mn修饰钙铝CO2载体，发现了修饰钙基CO2载体中存在Fe-Mn间相互作用强化了CO2吸收和水气变换制氢的机理，20次制氢循环中CO转化率高于99%，H2浓度约95%。研究了多种类型钙基CO2载体经过制氢/捕集CO2循环后的热化学储能特性、微观结构变迁特性、机械强度演变特性；揭示复合CO2载体中支撑体和催化剂对CaO/Ca(OH)2储能的影响机制，10次循环捕集CO2后的脱碳转化率以及水合转化率分别为0.57和0.81。研究了储能反应器类型、操作参数等对钙基CO2载体循环储能和颗粒机械性能的影响；构建了基于钙基CO2载体强化生物质制氢耦合CaO/Ca(OH)2储热系统的热力学模型，明确了耦合系统最优设计方案，阐释了热化学储能促进钙基CO2载体增强生物质制氢系统性能的机理，氢气产率达到1.08Nm3/kg-fuel，系统能量转化效率为42.1%，㶲效率为39.4%，CO2捕集效率大于90%。阐明了加压储能条件下多类型钙基CO2载体的CaO/CaCO3热化学储能规律和机理，发现钙铝铈CO2载体在30次加压储能循环中保持0.92的有效转化率和2924 kJ/kg以上的储热密度。研究了钙基CO2载体在生物质气化制氢过程中的H2S脱除特性，揭示了流态化下钙基CO2载体强化CO还原NO的反应机理。该项目研究为形成具有制氢、碳捕集和储能耦合的新工艺奠定了理论基础，有望促进高效低碳能源技术的发展。