摘要
钙基吸收剂循环煅烧/碳酸化反应吸收CO2是经济高效的CO2减排方法之一。为提高吸收剂的CO2循环捕集效率,文中利用粉煤灰对钙基吸收剂进行改性处理并考察其循环碳酸化性能。具体考察不同溶液条件下采用水合化法,以及对粉煤灰进行研磨、煅烧或碱浸等预处理手段优化制备改性吸收剂的碳酸化性能,并从成分和微观结构方面揭示吸收剂碳酸化特性提高的原因。结果表明,粉煤灰改性钙基吸收剂能提高吸收剂的碳酸化性能。其中,在50%乙酸溶液中水合条件下制备的改性吸收剂的碳酸化性能较好,经历8次循环反应碳酸化转化率较未改性CaO提高了84%;粉煤灰经研磨、煅烧或碱浸等预处理后制备的改性吸收剂的碳酸化性能得到进一步提高。粉煤灰改性钙基吸收剂在循环反应过程中生成CaSiO3和Ca12Al14O33,是改性吸收剂碳酸化性能得以提高并随循环次数增加衰减缓慢的主要原因。
Calcium looping cycle is one of the most promising technologies for CO2 capture, which is based on the reversible carbonation reaction of CaO. The calcium based sorbents were attempted to be modified with fly ash to enhance its CO2 capture capacity. The modification conditions were optimized by changing the hydration solution and pretreating the fly ash with grinding, calcination or alkali treatment. The carbonation property of the modified sorbents was investigated. The composition of and mierostructure of the preferable modified sorbents were also analyzed to reveal the mechanism of CO2 capture capacity enhancement. Results show that higher CO2 capture performance is achieved for the sorbent modified by coal fly ash in hydration compared with the pure CaO. The sorbents modified with coal fly ash in hydration with 50% acetic acid solution （CaO/FA Hyd（50%CA）） presented better CO2 capture performance compared with other modified sorbents. Carbonation conversion of CaO/FA Hyd（50%CA） is 84% higher than that of CaO after 8 cycles. Besides, sorbents modified by pretreatment of fly ash with grinding, calcination or alkaline leaching presented higher CO2 capture capacity than those without fly ash treatment. The composition analysis of these sorbents showed that CaSiO3 and Ca12Al14O33 was generated during the initial calcination and multiple cycles, which can restrain the sintering of sorbents leading to the improvement in surface area and pore volume of sorbents and thus the activity of sorbents.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2015年第20期5251-5257,共7页
Proceedings of the CSEE
基金
国家青年科学基金项目(51206024)
中国博士后科学基金项目(2011M500837)~~
