(2a) Chemical Looping Dehydrogenation of Light Alkanes: Redox Catalyst Design and Process Analysis

Olefin productions are among the most carbon intensive processes within the chemical industry. Ethylene production by naphtha or ethane cracking is very endothermic and requires extremely high temperatures. The significant energy demand requires large amounts of fuel to be burned, resulting in up to 2 tonnes of CO₂ per tonne of ethylene produced. Similarly, production of propylene, butenes, and butadiene are also highly energy intensive. To address these challenges, we have developed chemical looping – oxidative dehydrogenation (CL-ODH) approaches to convert light alkanes to alkenes. Under this scheme, an oxide based redox catalyst, also known as oxygen carrier, selectively oxidizes the hydrogen byproduct produced during dehydrogenation. When regenerated with air, the redox catalyst releases heat for an autothermal operation with high efficiency and low CO₂ emissions.

As a critical component that facilitates the entire CL-ODH process, redox catalyst development is highly important. Within this talk, the general design and optimization strategies for redox catalysts and their long-term CL-ODH performances are presented. High selectivity and olefin yields were achieved for CL-ODH of ethane, propane, and butane, making the CL-ODH system highly flexible.

To demonstrate the overall CL-ODH performance, process modeling and energy analysis results will also be discussed, showing the potential to reduce energy demand for ethylene production by up to 82%. Besides being used for centralized olefin production, a modular system that makes use of CL-ODH for liquid fuel production from distributed shale gas production sites is also briefly discussed.