Abstract:

Na₂CO₃-based CO₂ sorbent pellets were prepared via extrusion-spheronization method, and whose CO₂ capture performance was tested using a self-designed CO₂ sorption system. The microstructure, CO₂ capture performance and mechanical properties of Na₂CO₃-based sorbent pellets with different supports and loadings were investigated. The results showed that Na₂CO₃-based sorbent pellets with different supports exhibited relatively large discrepancy on CO₂ capture performance. The alumina-supported sorbent pellet (Na₂CO₃/Al₂O₃) possessed the highest CO₂ capture capacity of 1.14mmol/g. However, the calcium aluminate cement-supported sorbent pellets (Na₂CO₃/CA) exhibited the good mechanical properties and inferior CO₂ capture performance. Comprehensively considering the CO₂ capture performance and mechanical properties, Na₂CO₃/Al₂O₃ is the most suitable CO₂ sorbent. Moreover, the effect of loading amount of Na₂CO₃ on performance of Na₂CO₃/Al₂O₃ sorbent pellets was further studied. It was found that the microstructure, CO₂ capture performance and mechanical properties of Na₂CO₃/Al₂O₃ sorbent pellets were closely related to loading amount of NaCO₃. Although the pellets loaded with 60% of NaCO₃ exhibited the superior mechanical properties and CO₂ capture performance, their poor sphericity impeded the practical application. The Na₂CO₃/Al₂O₃ sorbent pellets loaded with 40% of NaCO₃ exhibited good CO₂ capture performance, mechanical properties and sphericity, whose CO₂ capture capacity is 1.36mmol/g. Therefore, the Na₂CO₃-based sorbent pellets prepared via extrusion-spheronization were suitable to be applied for CO₂ removal in power plant flue gas due to their good fluidization characteristics, CO₂ capture performance and mechanical properties.

Key words: CO₂ capture, Na₂CO₃-based sorbent pellets, extrusion-spheronization, loading amount, mechanical properties

摘要：

采用挤压-滚圆法制备Na₂CO₃基CO₂吸附剂微球颗粒，在自行设计的CO₂吸收系统中对制备的样品进行脱碳性能测试。结合相关表征测试，探明不同载体、不同负载量的Na₂CO₃基吸附剂的微观结构、脱碳性能以及机械性能的变化规律和内在原因。研究表明：不同载体的Na₂CO₃基吸附剂颗粒脱碳性能存在明显差异，其中氧化铝负载的吸附剂（Na₂CO₃/Al₂O₃）的脱碳性能最好，可达1.14mmol/g。铝酸钙水泥负载的吸附剂（Na₂CO₃/CA）机械性能较好，但其脱碳性能最差。结合吸附剂脱碳和机械性能的综合考量，Na₂CO₃/Al₂O₃是最为合适的CO₂吸附剂，并进一步研究不同Na₂CO₃负载量的影响。研究发现随着Na₂CO₃负载量的变化，吸附剂的微观结构、脱碳性能以及机械性能都存在明显的差异。虽然60%负载量的Na₂CO₃/Al₂O₃吸附剂颗粒的机械性能和脱碳效果较好，但其成球度较差，影响其实际应用。质量分数40%负载量的Na₂CO₃/Al₂O₃吸附剂颗粒具有良好的脱碳性能、机械性能以及成球度，CO₂脱除量为1.36mmol/g。总体而言，利用挤压-滚圆法制备的Na₂CO₃基吸附剂颗粒具有良好的流动特性、脱碳性能和机械性能，适用于电厂烟气中的CO₂脱除。

关键词: CO₂捕集, Na₂CO₃基吸附剂颗粒, 挤压-滚圆, 负载量, 机械性能