化石燃料的大规模使用造成了CO_(2)排放量逐年递增,其作为温室气体的主要成分加速了全球变暖及气候变化。CO_(2)的捕集、利用与存储(Carbon Capture,Utilization and Storage,简称CCUS)技术作为降低碳排放的有效方法,受到广泛关注。在...化石燃料的大规模使用造成了CO_(2)排放量逐年递增,其作为温室气体的主要成分加速了全球变暖及气候变化。CO_(2)的捕集、利用与存储(Carbon Capture,Utilization and Storage,简称CCUS)技术作为降低碳排放的有效方法,受到广泛关注。在诸多减少CO_(2)排放量的方法中,吸附法分离脱除CO_(2)具备良好的应用前景。固体吸附材料具有操作温度广、不易腐蚀设备、循环使用过程中产生的废物较少且易于处理等优点,被认为是理想的CO_(2)捕集材料。综述了3种类型的CO_(2)固体吸附剂的研究进展,包括低温、中温和高温固体吸附剂,指出了其优点和局限性及强化CO_(2)吸附性能与循环稳定性的措施。通常来说高压对低温固体吸附剂更加有利,但此条件下其选择性较差,且气流中存在的水分会水解某些吸附剂中的配位键,并与CO_(2)产生竞争吸附,导致CO_(2)吸附性能下降。因此低温吸附剂的吸附能力、吸附选择性和水热稳定性是研究重点。中温固体吸附剂中,类水滑石材料面临的挑战在于其独特的氢键堆积结构限制了其吸附容量进一步提高,而MgO吸附剂由于缺少基础活性位点以及固有的高晶格焓同样导致其吸附性能与吸附动力学较差。故中温吸附剂需要优先解决其低吸附能力和低循环稳定性的问题。高温固体吸附剂中,Li_(4)SiO_(4)吸附剂相比于Li_(2)ZrO_(3)吸附剂具备更低的制备成本以及更高的吸附容量,但2者皆面临动力学限制问题。CaO基吸附剂由于其理论吸附容量高、适用范围广、成本低廉、无毒、具备快速的吸附动力学特性等优点受到广泛关注。而在CO_(2)吸附/脱附多循环过程中,钙基吸附剂由颗粒烧结引发的热失活以及颗粒磨损问题是限制其进一步发展的最大障碍。针对这些问题可采用高温预处理、水合作用、化学掺杂、酸改性等方式来提高其吸附性能与多循环稳定性。此外,造粒及规模化制备技术是提高其工业应用潜力需解决的瓶颈问题。展开更多
At present,insufficient works have provided insights into the application of adsorption to remove CO_(2) in flue gas below room temperatures under ambient pressure.In this work,the effects of temperature,CO_(2) partia...At present,insufficient works have provided insights into the application of adsorption to remove CO_(2) in flue gas below room temperatures under ambient pressure.In this work,the effects of temperature,CO_(2) partial pressure and moisture on dynamic adsorption characteristics for CO_(2) are conducted for various adsorbents.Based on our findings,lower the adsorbing temperature can drastically enhance the adsorption of carbon dioxide over molecular sieves and activated carbon.Among various adsorbents,13X molecular sieve shows highest adsorption capacity.With a concentration of 10%CO_(2) in flue gas,the specific adsorption capacity of CO_(2) over 13X molecular sieve is 0.11,2.54 and 5.38 mmol/g at 80℃,0℃ and -80℃,respectively.In addition,the partial pressure of CO_(2) also has a significant impact on the adsorption capacity.With the increment of the concentration of CO_(2) from 1%to 10% under 0℃,the specific capacity of 13X molecular sieve increases from 1.212 mmol/g to 2.538 mmol/g.Water vapor in flue gas can not only reduce the specific adsorption capacity of CO_(2) due to competing adsorption,but also increase the heat penalty of molecular sieve regeneration due to the water adsorption.An overall analysis is conducted on the energy penalty of capture 1 ton CO_(2) at various adsorption temperatures between -80℃ and 80℃,considering both the heat penalty of molecular sieve regeneration as well as the energy penalty for cooling the adsorber.It is found that the lowest energy penalty is about 2.01 GJ/ton CO_(2) when the adsorption is conducted at 0℃.展开更多
文摘化石燃料的大规模使用造成了CO_(2)排放量逐年递增,其作为温室气体的主要成分加速了全球变暖及气候变化。CO_(2)的捕集、利用与存储(Carbon Capture,Utilization and Storage,简称CCUS)技术作为降低碳排放的有效方法,受到广泛关注。在诸多减少CO_(2)排放量的方法中,吸附法分离脱除CO_(2)具备良好的应用前景。固体吸附材料具有操作温度广、不易腐蚀设备、循环使用过程中产生的废物较少且易于处理等优点,被认为是理想的CO_(2)捕集材料。综述了3种类型的CO_(2)固体吸附剂的研究进展,包括低温、中温和高温固体吸附剂,指出了其优点和局限性及强化CO_(2)吸附性能与循环稳定性的措施。通常来说高压对低温固体吸附剂更加有利,但此条件下其选择性较差,且气流中存在的水分会水解某些吸附剂中的配位键,并与CO_(2)产生竞争吸附,导致CO_(2)吸附性能下降。因此低温吸附剂的吸附能力、吸附选择性和水热稳定性是研究重点。中温固体吸附剂中,类水滑石材料面临的挑战在于其独特的氢键堆积结构限制了其吸附容量进一步提高,而MgO吸附剂由于缺少基础活性位点以及固有的高晶格焓同样导致其吸附性能与吸附动力学较差。故中温吸附剂需要优先解决其低吸附能力和低循环稳定性的问题。高温固体吸附剂中,Li_(4)SiO_(4)吸附剂相比于Li_(2)ZrO_(3)吸附剂具备更低的制备成本以及更高的吸附容量,但2者皆面临动力学限制问题。CaO基吸附剂由于其理论吸附容量高、适用范围广、成本低廉、无毒、具备快速的吸附动力学特性等优点受到广泛关注。而在CO_(2)吸附/脱附多循环过程中,钙基吸附剂由颗粒烧结引发的热失活以及颗粒磨损问题是限制其进一步发展的最大障碍。针对这些问题可采用高温预处理、水合作用、化学掺杂、酸改性等方式来提高其吸附性能与多循环稳定性。此外,造粒及规模化制备技术是提高其工业应用潜力需解决的瓶颈问题。
基金the support from the China Huaneng Group(Grant Nos.HNKJ21-H65).
文摘At present,insufficient works have provided insights into the application of adsorption to remove CO_(2) in flue gas below room temperatures under ambient pressure.In this work,the effects of temperature,CO_(2) partial pressure and moisture on dynamic adsorption characteristics for CO_(2) are conducted for various adsorbents.Based on our findings,lower the adsorbing temperature can drastically enhance the adsorption of carbon dioxide over molecular sieves and activated carbon.Among various adsorbents,13X molecular sieve shows highest adsorption capacity.With a concentration of 10%CO_(2) in flue gas,the specific adsorption capacity of CO_(2) over 13X molecular sieve is 0.11,2.54 and 5.38 mmol/g at 80℃,0℃ and -80℃,respectively.In addition,the partial pressure of CO_(2) also has a significant impact on the adsorption capacity.With the increment of the concentration of CO_(2) from 1%to 10% under 0℃,the specific capacity of 13X molecular sieve increases from 1.212 mmol/g to 2.538 mmol/g.Water vapor in flue gas can not only reduce the specific adsorption capacity of CO_(2) due to competing adsorption,but also increase the heat penalty of molecular sieve regeneration due to the water adsorption.An overall analysis is conducted on the energy penalty of capture 1 ton CO_(2) at various adsorption temperatures between -80℃ and 80℃,considering both the heat penalty of molecular sieve regeneration as well as the energy penalty for cooling the adsorber.It is found that the lowest energy penalty is about 2.01 GJ/ton CO_(2) when the adsorption is conducted at 0℃.
