Fuel ( IF 6.7 ) Pub Date : 2023-08-16 , DOI: 10.1016/j.fuel.2023.129326
Iván Samprón , Francisco García-Labiano , María T. Izquierdo , Luis F. de Diego
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Chemical Looping Gasification (CLG) has emerged recently as a promising technology for producing non N2-diluted syngas without the need for an external power supply or the expensive use of pure O2. Many studies have focused on development of oxygen carriers since they are considered a crucial factor in CLG processes. Fe2O3/Al2O3 (FeAl) oxygen carriers have been proposed due to previous experience in Chemical Looping Combustion (CLC). However, the aggressive conditions of gasification cause a decrease in the mechanical stability of the particles, which can be a challenge for their use in CLG. In this work, the operating conditions and Fe-content required to maintain the particle integrity of oxygen carrier particles during redox cycles in both CLC and CLG operations were determined. Long-term tests, consisting of 300 redox cycles, were conducted in a TGA to simulate the operation in a continuous unit and the results were compared with attrition data obtained from a 1.5 kWth CLG unit. Three oxygen carriers with varying Fe2O3-content (10, 20 and 25 wt%) were used, and three different solid conversions (0–25 %, 75–100 % and 0–100 %) were performed to emulate CLC or CLG atmospheres at three temperatures (850 °C, 900 °C and 950 °C). The evolution of the microstructure of particles was analyzed using a scanning electron microscope (SEM) and it was found that the lower the Fe2O3 content in the particles, the greater their stability in redox cycles, an increase in the reaction temperature led to a more rapid degradation of the oxygen carrier particles, and the solid conversion variation and degree of reduction/oxidation during redox cycles strongly influenced the evolution of the mechanical stability of the oxygen carrier particles.
中文翻译:

了解化学循环气化条件下 Fe2O3/Al2O3 氧载体的结构变化
化学循环气化(CLG)最近作为一种有前途的技术出现,用于生产非N 2稀释的合成气,而不需要外部电源或昂贵地使用纯O 2。许多研究都集中在氧载体的开发上,因为它们被认为是 CLG 过程中的关键因素。Fe 2 O 3 /Al 2 O 3(FeAl) 氧载体是根据化学链燃烧 (CLC) 的先前经验而提出的。然而,恶劣的气化条件会导致颗粒的机械稳定性下降,这对其在 CLG 中的使用可能是一个挑战。在这项工作中,确定了 CLC 和 CLG 操作中氧化还原循环期间保持氧载体颗粒的颗粒完整性所需的操作条件和 Fe 含量。在 TGA 中进行了由 300 个氧化还原循环组成的长期测试,以模拟连续装置的运行,并将结果与从 1.5 kW th CLG 装置获得的磨损数据进行比较。具有不同 Fe 2 O 3的三种氧载体使用含量(10、20 和 25 wt%),并进行三种不同的固体转化(0–25%、75–100% 和 0–100%),以模拟三种温度(850 °C)下的 CLC 或 CLG 气氛、900°C 和 950°C)。利用扫描电子显微镜(SEM)分析了颗粒微观结构的演变,发现颗粒中Fe 2 O 3含量越低,其在氧化还原循环中的稳定性越高,反应温度的升高导致颗粒的微观结构发生变化。氧载体颗粒的更快降解以及氧化还原循环期间的固体转化变化和还原/氧化程度强烈影响氧载体颗粒的机械稳定性的演变。