钢渣基高温CO2吸附剂的结构调控及其抗烧结机理研究

High-temperature CO2 sorbents are keys to the sorption-enhanced steam methane reforming (SESMR) processes, which can not only increase the conversion of methane, but also can in suit capture the CO2. In the view of the cost of raw materials of high-temperature layered double hydroxides (LDHs) type CO2 sorbents is high, and its sintering mechanism is not clear. In this project, the high-temperature LDH-type CO2 sorbents will be prepared from steel slag containing rich calcium, magnesium, aluminum and iron. To investigate the CO2 capture capacity by tuning the crystal phase, cell, interlayer spacing, particle size, specific surface area and pore structure of LDH. The contribution of the skeleton of MgO, Al2O3 in the LDH-type sorbent to its anti-sintering properties was studied and its anti-sintering mechanism will be clarified. In the meantime, the CO2 sorption-desorption kinetics will be studied and the operating conditions of these sorbents in SESMR process will be optimized. Furthermore, the action mechanism of alkali site on the surface of LDH-type sorbent with CO2, as well as the mechanism of sorption and desorption will be revealed to determine the carbonation mechanism of the LDH-type sorbent. The ultimate goal of this proposed project is to develop CO2 sorbents which are highly efficient and stable, and suitable to the SESMR operation conditions.

高温CO2吸附剂在吸附增强型甲烷水蒸气重整产氢工艺（SESMR）中具有重要应用，在提高甲烷转化率的同时，可以实现在线捕集CO2。针对目前类水滑石（LDH）型高温CO2吸附剂合成原料成本高，抗烧结机理不明确等问题。本项目拟以含有丰富的钙、镁、铝、铁等成分的钢渣为原料制备LDH型高温CO2吸附剂，并通过对LDH晶相、晶胞、层间距、粒径、比表面积及孔结构等调控，考察这些因素对其CO2吸附性能的影响规律。将重点考察MgO，Al2O3的骨架作用对LDH型CO2吸附剂抗烧结性能提升方面的贡献，阐明LDH型CO2吸附剂的抗烧结机理。通过探究LDH型CO2吸附剂的吸-脱附动力学、热力学等，优化其在SESMR工艺中的运行参数。通过揭示LDH型CO2吸附剂表面碱位与CO2的作用机理及吸-脱附机制，确定其碳酸化机理，最终构建出更适合在SESMR工艺中应用的高效、稳定、廉价的高温CO2吸附剂。

高温CO2吸附剂在吸附增强型甲烷水蒸气重整产氢工艺（SESMR）中具有重要应用，在提高甲烷转化率的同时，可以实现在线捕集CO2。本项目利用含有丰富钙、镁、铝、铁等成分的钢渣为原料制备了钢渣基高温CO2吸附剂，并通过对其制备过程中晶相、粒径、比表面积及孔结构等因素的调控，考察了这些因素对其CO2吸附性能的影响规律。制备的吸附剂的CO2吸附量可达14.54mmol/g，利用Na2CO3对其改性后，其CO2吸附量可达16.18mmol/g，为CaO理论吸附容量的91%。考察了MgO、Al2O3的骨架作用对钢渣基高温CO2吸附剂抗烧结性能提升方面的贡献，阐明了钢渣基高温CO2吸附剂的抗烧结机理。证明了由于钢渣基高温CO2吸附剂中含有MgO、Al2O3等惰性物质，虽然它们不直接参与CO2的吸附，但它们可以在煅烧过程中作为支撑吸附剂的框架，以防止吸附剂坍塌。此外，通过探究钢渣基高温CO2吸附剂的吸-脱附动力学、热力学等，优化了其在SESMR工艺中的运行参数，最终构建出了更适合在SESMR工艺中应用的高效、稳定、廉价的高温CO2吸附剂。本项目成果将为固体废弃物基CO2吸附剂的开发应用提供理论依据和技术支持，也为钢渣资源化利用提供新的途径。