AIR: Towards a CO2-free, Sustainable, Ethylene Oxide Technology

传统的环氧乙烷（EO）工艺从乙烯和EO的燃烧中排放CO2作为副产物（大约3.4 MM吨/年），消除CO2几十年来一直是工业化学中的重大挑战。在NSF资助的一个项目中，堪萨斯大学最近展示了一种替代技术概念，对EO的选择性为99%，没有可检测到的CO2形成。该替代方法基于在25- 40 ° C和~50巴下使用甲基三氧化铼（MTO）作为催化剂用H2 O2进行的均相乙烯氧化。该提案解决了商业化的主要障碍，即，可回收的MTO催化剂的设计和演示。异质载体和大体积可溶性聚合物（能够通过纳滤膜保留在溶液中）都被考虑在内。通过初步的经济分析，已经建立了实际可行性的定量催化剂性能指标（活性、选择性和耐久性），并将指导催化剂设计。项目目标的成功完成将产生用于环氧化反应的新型可回收催化剂配方。连续乙烯膨胀液相催化反应器的示范将是同类产品中的第一个。ADM（对植物油的环氧化感兴趣）、Evonik（主要的H2 O2生产商）和PG（主要的EO消费者）人员的项目指导增加了项目成功和最终商业化的可能性。拟议的概念有可能大大节省石油和天然气储量（约1300万桶原油/年），并减少作为副产品的碳排放（每年340万公吨二氧化碳）。将该技术应用于含有乙烯和乙烷的混合进料还将导致与常规加工中所需的分离相关的显著的能量节省。这项拟议工作的技术成果将被整合到一个正在进行的课程，名为可持续化学工艺的发展，影响本科和研究生课程。

Conventional ethylene oxide (EO) processes emit CO2 as byproduct (roughly 3.4 MM tons/yr) from the combustion of both the ethylene and EO, the elimination of which has been a major grand challenge in industrial chemistry for decades. In a NSF-funded project, an alternate technology concept that is 99% selective toward EO was recently demonstrated at the University of Kansas with no detectable CO2 formation. This alternate process is based on homogeneous ethylene oxidation with H2O2 at 25-40C and ~50 bars using methyltrioxorhenium (MTO) as catalyst. This proposal addresses the key barrier to commercialization, viz., the design and demonstration of a recyclable MTO catalyst. Both heterogeneous supports and bulky soluble polymers (capable of retention in solution by nanofiltration membranes) are being considered. Quantitative catalyst performance metrics (activity, selectivity and durability) for practical viability have been established through preliminary economic analysis and will guide catalyst design. Successful completion of the project objectives will result in novel, recyclable catalyst formulations for epoxidation reactions in general. The demonstration of a continuous ethylene-expanded liquid phase catalytic reactor will be the first of its kind. The project guidance from ADM (interested in epoxidation of vegetable oils), Evonik (a major H2O2 producer) and P&G (a major EO consumer) personnel increases the probability of project success and eventual commercialization. The proposed concept has the potential to result in significant conservation of oil and gas reserves (~13 million barrels crude oil/year) and reduction of carbon emissions as byproduct (3.4 million metric tons of CO2 each year). The application of this technology to mixed feeds containing ethylene and ethane will also result in significant energy savings associated with their separation required in conventional processing. The technical outcomes from this proposed work will be integrated into an ongoing course titled Development of Sustainable Chemical Processes, impacting both the undergraduate and graduate curricula.