生物质基修饰钙基吸收剂捕集CO2协同还原NOx机理研究

Carbonation/calcination of calcium based sorbents is one of the most promising technologies for CO2 capture. Sintering and attrition of calcium based sorbents during the cycling are the key problems that hinder its development. In term of the severe emission regulation and further development of the CO2 capture technology, it is essential and of huge potentials to develop novel calcium based sorbents of high reactivity, anti-sintering and attrition resistant to be able to reduce NOx and SO2. Based on previous research, novel calcium based sorbents is proposed to be developed with biomass such as sawdust being the pore and char forming agent coupled with aluminate cement as the binder to enhance its anti-sintering and attrition resistant. The sorbents with excellent pore structure and char is expected to achieve great CO2 capture performance and NOx reduction. The activation mechanism of biomass on calcium based sorbents, carbonation and attrition performance of the sorbents, NOx reduction mechanism of the sorbents during calcination or carbonation, as well as the interaction of carbonation and NOx reduction will be investigated with the instruments such as TGA, fixed bed and fluidized bed system, and the techniques such as SEM-EDX, XRD, TG-FTIR, N2 absorption/desorption and XPS, etc. The research will provide essential theory foundation for development of CO2 capture technology coupled with multiple pollutant reduction.

钙基吸收剂循环煅烧/碳酸化捕集CO2是目前最具可行性的CO2捕集技术之一。在循环反应过程中吸收剂的高温烧结和易磨损是阻碍该技术推广的关键问题。研究一种抗烧结抗磨损高活性的钙基吸收剂，实现CO2高效捕集并协同还原NOx，对推动钙循环技术及烟气联合脱碳脱氮工艺发展具有重要研究意义和巨大的发展潜力。本项目在前期研究基础上，提出以木屑等生物质作活化剂，辅以高铝水泥等作粘结剂提高吸收剂抗烧结抗磨损能力，制备孔隙丰富伴生物质焦，可促进NOx还原的新型钙基吸收剂。基于TGA、固定床及流化床系统，结合SEM-EDX、XRD、TG-FTIR、N2吸附分析仪，XPS等手段，研究生物质修饰活化钙基吸收剂的作用机理，吸收剂的碳酸化性能和磨损性能，吸收剂煅烧或碳酸化过程中生物质热解产物对NOx的还原机理，以及碳酸化反应与NOx还原的相互作用机制。为优化设计碳捕集与多种污染物协同脱除工艺提供重要的理论基础。

钙基吸收剂流化床循环煅烧/碳酸化捕集CO2是目前最具可行性的CO2 捕集技术之一。在循环煅烧/碳酸化过程中，吸收剂烧结及孔隙堵塞是造成其循环碳酸化性能随循环次数增加衰减迅速的主要原因，维持吸收剂高效持续的碳酸化性能，对该技术发展具有重要研究意义。以生物质基等作修饰剂活化吸收剂，以高铝水泥作粘结剂并增强修饰吸收剂的抗烧结和抗磨损性能，基于TGA和固定床系统，研究各种修饰方法对修饰钙基吸收剂的影响作用，获得了最佳修饰方法及生物质修饰钙基吸收剂循环碳酸化规律；从微观孔隙结构、物相结构等角度揭示生物质修饰钙基吸收剂在循环反应过程中的孔隙结构变化以及晶体结构变化规律，分析其对修饰钙基吸收剂的抗烧结影响机制；在固定床反应系统上对生物质修饰吸收剂在碳酸化反应条件下的NOx还原特性进行考察，获得了修饰钙基吸收剂在碳酸化反应过程的NOx还原率以及相关机制，基本达到课题预期的研究目的，同时为后续开发高效经济的钙基吸收剂协同NOx强化还原脱除提供有益的理论基础。