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Carbonation of Limestone Derived CaO for Thermochemical Energy Storage: From Kinetics to Process Integration in Concentrating Solar Plants
ACS Sustainable Chemistry & Engineering ( IF 8.4 ) Pub Date : 2018-04-19 00:00:00 , DOI: 10.1021/acssuschemeng.8b00199
C. Ortiz 1 , J. M. Valverde 1 , R. Chacartegui 2 , L. A. Perez-Maqueda 3
Affiliation  

Thermochemical energy storage (TCES) is considered as a promising technology to accomplish high energy storage efficiency in concentrating solar power (CSP) plants. Among the various possibilities, the calcium-looping (CaL) process, based on the reversible calcination–carbonation of CaCO3 stands as a main candidate due to the high energy density achievable and the extremely low price, nontoxicity, and wide availability of natural CaO precursors such as limestone. The CaL process is already widely studied for CO2 capture in fossil fuel power plants or to enhance H2 production from methane reforming. Either one of these applications requires particular reaction conditions to which the sorbent performance (reaction kinetics and multicycle conversion) is extremely sensitive. Therefore, specific models based on the conditions of any particular application are needed. To get a grip on the optimum conditions for the carbonation of limestone derived CaO in the CaL-CSP integration, in the present work is pursued a multidisciplinary approach that combines theoretical modeling on reaction kinetics, lab-scale experimental tests at relevant CaL conditions for TCES, process modeling, and simulations. A new analytic equation to estimate the carbonation reaction rate as a function of CO2 partial pressure and temperature is proposed and validated with experimental data. Using the kinetics analysis, a carbonator model is proposed to assess the average carbonation degree of the solids. After that, the carbonator model is incorporated into an overall process integration scheme to address the optimum operation conditions from thermodynamic and kinetics considerations. Results from process simulations show that the highest efficiencies for the CaL-CSP integration are achieved at carbonator absolute pressures of ∼3.5–4 bar, which leads to an overall plant efficiency (net electric power to net solar thermal power) around 41% when carbonation is carried out at 950 °C under pure CO2.

中文翻译:

石灰石衍生的CaO的热化学储能碳化:从动力学到集中式太阳能发电厂的过程集成

热化学能量存储(TCES)被认为是在聚光太阳能(CSP)电厂中实现高能量存储效率的有前途的技术。在各种可能性中,钙-循环(CAL)过程中,基于碳酸钙的可逆煅烧碳化3代表作为主要候选由于高能量密度可达到和极低的价格,无毒性,以及自然的CaO广泛的可用性石灰石等前体。CaL工艺已被广泛研究用于化石燃料发电厂中的CO 2捕集或增强H 2甲烷重整生产。这些应用中的任何一种都需要特殊的反应条件,对此吸附剂的性能(反应动力学和多循环转化)非常敏感。因此,需要基于任何特定应用程序条件的特定模型。为了掌握在CaL-CSP集成中石灰石衍生的CaO碳酸化的最佳条件,在本工作中,我们寻求一种多学科的方法,该方法结合了反应动力学的理论模型,在相关CaL条件下进行TCES的实验室规模的实验测试。 ,流程建模和仿真。估算碳酸化反应速率与CO 2的函数的新解析方程提出了分压和温度分压并通过实验数据进行了验证。使用动力学分析,提出了碳酸化器模型来评估固体的平均碳酸化度。之后,将碳酸化器模型合并到总体过程集成方案中,以从热力学和动力学方面考虑最佳运行条件。过程模拟的结果表明,碳酸化器的绝对压力为〜3.5–4 bar时,CaL-CSP集成的效率最高,碳酸化时,整个工厂的效率(净电能至净太阳能热能)约为41%在950°C和纯CO 2下进行
更新日期:2018-04-19
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