Semester

Spring

Date of Graduation

2021

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Jianli Hu

Committee Member

Charter Stinespring

Committee Member

Debangsu Bhattacharyya

Committee Member

V'yacheslav Akkerman

Committee Member

Christina Wildfire

Abstract

Ethane is the second-largest component in natural gas and is typically separated out to minimize condensation in the pipelines. The technical difficulties and cost associated with the transportation and the storage of ethane have led companies to start burning natural gas to produce power or flaring which attributes to the global CO2 emission problem. The conversion of ethane to higher-value liquid products is of increasing importance so that the natural gas can be safely utilized and cost-effectively transported. Existing commercial technologies used to convert ethane to liquid chemical products are typically based on the indirect syngas route, such as dry and steam reforming. Although, the direct conversion of ethane to aromatic products by non-oxidative dehydroaromatization has been studied for several decades, due to technical challenges no commercialization has occurred. The challenges include the design of highly selective catalysts and reactors systems to facilitate long-term catalyst stability. Conventional catalytic technologies have resulted in little or no progress towards commercialization. Thus, novel reaction engineering concepts are required, not only to develop a robust catalyst but also to revolutionize the entire process by applying non-conventional heating. The selective heating nature of microwave irradiation has demonstrated energy efficiency by lowering bulk catalyst temperatures and achieve higher selectivity due to suppressing further side reactions of undesired products.

This research aims to develop a method to increase catalyst stability, reactor efficiency, and product selectivity for the ethane dehydroaromatization reaction (EDHA). Molybdenum loaded zeolite supported H/ZSM-5 catalysts were studied for the EDHA reaction under thermally heated and/or microwave heated conditions. Promoters such as Fe and Zn were tested for the EDHA reaction over five reaction and regeneration cycles. The ability of the microwave to regenerate a deactivated catalyst in a microwave reactor was also tested under an O2 and a CO2 atmosphere. The reaction mechanism of EDHA was further investigated by using two different heating modes. A microwave fixed-bed reactor (MWFB) was used and its performance was compared to a conventional thermal fixed-bed reactor (CTFB). Catalyst bed preheating by thermally heated hot air and catalyst bed fluidization were investigated to enhance the utilization of the catalyst bed and the selectivity to aromatics for the microwave heated EDHA reaction.

Embargo Reason

Publication Pending

Available for download on Friday, April 29, 2022

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