How does the oxidation and reduction time affect the chemical looping epoxidation of ethylene?
How does the oxidation and reduction time affect the chemical looping epoxidation of ethylene?
复制标题
氧化和还原时间如何影响乙烯的化学链环氧化？
DOI：
10.1007/s43938-022-00011-4
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Gebers J
中科院分区：
文献类型：
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作者：
Gebers J
在锶铁酸钙钛矿（SrFeO3-δ）负载的银催化剂上进行了乙烯的化学环环氧化反应（CLE）。CLE包括在乙烯中的还原步骤，其中氧气从载体转移到Ag催化剂以形成环氧乙烷（EO），以及单独的再生步骤，其中载体在空气中再氧化。考察了改变还原和氧化时间对乙烯转化率和环氧乙烷选择性的影响。实验在270°C的Ag(15wt .%)/SrFeO3-δ填充床上进行，每小时气体空速为9600 h−1，总操作时间为bbb40 h。当还原步骤时间从1 min增加到3 min时，对EO的选择性仅下降0.4%，表明CLE可以在保持高选择性的情况下延长还原时间。增加再氧化步骤的持续时间导致选择性和转化率增加，但当氧化时间从10到15分钟变化时，性能的总体改善是最小的；因此，CLE可以在较短的氧化时间内运行。在不影响CLE性能的情况下，通过将氧化步骤的压力增加到2.5 bar，再氧化步骤的持续时间进一步缩短至5 min。在1.5分钟还原和5分钟再氧化的步骤下，以伪稳定方式产生EO的CLE装置将需要4个填充床反应器并联运行。我们还研究了Ag2O在CLE过程中的作用，证明了这种氧化物对EO没有选择性。
The chemical looping epoxidation (CLE) of ethylene was performed over an Ag catalyst supported on strontium ferrite perovskite (SrFeO3-δ). CLE consists of a reduction step in ethylene where oxygen is transferred from the support to the Ag catalyst to form ethylene oxide (EO), and a separate regeneration step, in which the support is reoxidised in air. The effect of altering the reduction and oxidation times was investigated, analysing changes in the conversion of ethylene and selectivity to EO. Experiments were conducted at 270 °C in a packed bed of Ag(15 wt.%)/SrFeO3-δwith a gas hourly space velocity of 9600 h−1and a total operation time > 40 h. When the time of the reduction step was increased from 1 to 3 min, selectivity to EO only decreased by 0.4%, demonstrating that CLE can run with prolonged reduction times while maintaining high selectivity. Increased duration of the reoxidation step resulted in both selectivity and conversion increasing, but when varying the oxidation time from 10 to 15 min, the overall improvement in the performance was minimal; thus, CLE can feasibly operate at shortened oxidation times. By increasing the pressure during the oxidation step to 2.5 bar, the duration of the reoxidation step was further shortened to 5 min without impacting the CLE performance. With 1.5 min reduction and 5 min reoxidation steps, a CLE installation producing EO in a pseudo-steady manner would require 4 packed bed reactors operating in parallel. The role of Ag2O in the CLE process was also investigated, demonstrating that the oxide was not selective towards EO.
DOI：
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发表时间：
2009
期刊：
影响因子：
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作者：
Shahla Aryana;M. Ahmadi;V. Gomes;J. Romagnoli;K. Ngian
通讯作者：
K. Ngian
影响因子：
7.3
作者：
Chan, Martin S. C.;Marek, Ewa;Dennis, J. S.
通讯作者：
Dennis, J. S.
DOI：
10.1016/j.apcatb.2020.119821
发表时间：
2021-06
期刊：
Applied Catalysis B: Environmental
影响因子：
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作者：
S. Gabra;Ewa J. Marek;S. Poulston;G. Williams;J. S. Dennis
通讯作者：
S. Gabra;Ewa J. Marek;S. Poulston;G. Williams;J. S. Dennis