Semester

Spring

Date of Graduation

2019

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Hanjing Tian

Committee Co-Chair

Jianli Hu

Committee Member

Jianli Hu

Committee Member

John W. Zondlo

Committee Member

Xingbo Liu

Committee Member

Zili Wu

Abstract

The shale gas revolution has significantly changed the energy landscape in US. The technical-feasible, energy-effective schemes for shale gas combustion and utilization, especially from remote resources, have attracted increasing interest due to expensive transportation/distribution cost. In this research, for the first time, chemical looping combustion (CLC) of methane with inherent CO2 capture, oxidative coupling of methane (OCM) and dehydro-aromatization (DHA) of ethane are systematically studied as promising alternatives at O2-rich, O2-lean and non-oxidative conditions, respectively.

Chemical looping combustion is bridging clean fuel combustion in energy production with inherent CO2 capture. CLC utilized an oxygen carrier (OC) to transfer oxygen to the fuel source in O2-rich conditions. However, the fundamental kinetics of surface structure with oxygen transfer on OC, as well as the reduction activity and coupled selectivity have yet been established. OCM directly converts methane to produce C2 hydrocarbons (C2H6 and C2H4) in O2-lean condition. Perovskite catalysts have shown promising activity and selectivity to C2, but the role of surface acidity of perovskite-type catalyst on OCM kinetics has not been revealed. Non-oxidative ethane DHA provides an economical and environmentally friendly alternative for aromatics and H2 production. Pillared ZSM-5 with hierarchical pores could amplify the mass/heat transfer, which is a promising catalyst for DHA reaction. However, very few studies have been reported to directly associate the thickness of lamellar layers with reactant diffusion, Si/Al ratios, surface acidities as well as catalytic reactivity of ethane-DHA reaction.

The research objective is to provide fundamental insights of surface structure-performance relationship of model catalysts for catalytic C2/C3 conversion in three aspects: 1) the oxygen transfer mechanisms in CLC by using surface calcium-doped (1, 2 and 4 wt%) copper oxides based OC; 2) the effect of surface compositions of perovskites on the OCM by using SrTiO3 as a model catalyst is investigated; and 3) a regenerable MoOx/lamellar ZSM-5 based on the strategy of optimizing micro/mesopores structure of zeolite framework, targeting high ethane conversion and aromatic selectivity by optimizing Si/Al ratio, surface acidity and diffusion path. The work offers several economic-viable and technical-feasible solutions for shale gas utilization to value-added products.

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