Demonstrating on-demand production of bio-ethylene oxide in a two-step dehydration-epoxidation process with chemical looping operations
Demonstrating on-demand production of bio-ethylene oxide in a two-step dehydration-epoxidation process with chemical looping operations
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DOI：
10.1016/j.cej.2024.148804
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发表时间：
2024-02
影响因子：
15.1
通讯作者：
Joseph C. Gebers;Ewa J. Marek
中科院分区：
文献类型：
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作者：
Joseph C. Gebers;Ewa J. Marek
环氧乙烷（EO）是一种关键的化学中间体，几乎完全由石油化学衍生的乙烯生产。目前，EO生产涉及在Ag/Al 2 O3上用O2环氧化乙烯-这是化学行业中二氧化碳排放量最高的工艺之一（Boulamanti和莫亚，2017年）。与现有方法和缓慢的工艺启动相关的易燃性危害阻碍了小规模、灵活的操作或与间歇性可用的可再生资源的一致性。本文提供了一种用于从生物乙醇按需生产生物EO的新方法。实验室级或变性的乙醇首先在HZSM-5（在280 °C下）或γ-Al 2 O3（在350 °C下）催化剂上脱水成乙烯，产生乙烯和水。然后在270 °C下，使用来自固体SrFeO 3的晶格氧，在Ag/SrFeO 3上将乙烯流选择性氧化成EO，用于驱动化学环氧化（CLE）。结果表明，当乙烯转化率为15%时，环氧乙烷的选择性为57%，超过了现有的纯Ag/α-Al 2 O3和O2的合成方法。结果表明，水的存在在一定的百分比水平增强非选择性燃烧。原位去除水，可能与两种催化剂之间的干燥材料的附加层，被证明是有效的，在提高过程的性能，达到选择性EO的50%，在12%的乙烯转化率。当使用变性乙醇或间歇进行实验时，催化剂没有显示出失活的迹象。因此，我们的新工艺可以保持离线而不会受到惩罚，允许按需生产并与可再生资源完全一致。
Ethylene oxide (EO) is a key chemical intermediate produced almost exclusively from petrochemically derived ethylene. Currently, EO manufacturing involves epoxidation of ethylene with O2over Ag/Al2O3- one of the highest CO2-emitting processes in the chemical sector (Boulamanti and Moya, 2017). The flammability hazards associated with incumbent methods and sluggish process start-ups prevent small-scale, flexible operations or alignment with intermittently available renewable resources. Presented herein is a novel process for on-demand production of bio-EO from bioethanol. Ethanol, laboratory-grade or denatured, was first dehydrated to ethylene over HZSM-5 (at 280 °C) or γ-Al2O3(at 350 °C) catalysts, producing ethylene and water. The ethylene stream was then selectively oxidised to EO over Ag/SrFeO3at 270 °C using lattice oxygen from a solid – SrFeO3, employed to drive chemical looping epoxidation (CLE). For a configuration where the dehydration and epoxidation reactions were carried out in separate reactors, the process produced EO with 57 % selectivity at 15 % conversion of ethylene, thus exceeding the incumbent approach with pure Ag/α-Al2O3and O2.In an alternative configuration, experiments were carried out in one dehydration-epoxidation reactor layered with two catalysts: HZSM-5 and Ag/SrFeO3. The results revealed that water presence at a percentage level enhanced unselective combustion.In-situremoval of water, possible with an additional layer of a drying material between the two catalysts, proved effective in boosting the process performance, reaching selectivity to EO of 50 % at 12 % conversion of ethylene. The catalysts showed no sign of deactivation when using denatured ethanol or when performing experiments intermittently. Hence, our novel process can be kept offline without penalty, allowing for on demand production and complete alignment with renewable resources.