Over 200 billion feet per year of natural gas at remote production sites is flared in the United States. This wastes valuable resources, increases air emissions and burns profit. West Virginia University researchers have been developing several innovative approaches to utilize natural gas. These approaches include the catalytic approach, electrocatalytic approach and advanced combustion approach.
Catalytic approach: The efficient direct conversion of flare gas to value-added liquid chemicals through single step dehydroaromatization (DHA) has been studied for decades but remains non-commercially viable. DHA’s major issues include rapid catalyst deactivation and comparatively low single-pass conversion levels of ~10% (700oC). The most important step in methane DHA is the activation of strong C-H bonds in methane. WVU researchers Hu and Bhattacharyya have demonstrated that microwave enhanced DHA catalysis boosts the rate of aromatics production by two orders of magnitude. The novelty of the technique is the use of electromagnetic energy to enable activation and transformation of chemical bonds at the interface of the catalyst and the reactants, thus lowering activation energy, achieving higher yields at a relatively low overall temperature. The research has led to a fundamental understanding of chemical and physical processes at the molecular scale including selective bond activation and novel separation science with implications beyond methane conversion.
Electrocatalytic approach: With one-step conversion of chemical energy directly into electrical energy, solid oxide fuel cells (SOFCs) have the ability to achieve efficiencies of >60% and up to 97% carbon capture. Two barriers hinder NG-fueled SOFC performance. First, the relatively retarded oxidation reaction rate at the anode constrains output current and allows coke formation when free carbon accumulates at the anode. Second is the lack of an effective coke-tolerant catalyst to break stable C-H bonds. WVU researcher Liu harness overpotential-excited electrocatalytic conversion of NG to enhance oxidation and will employ atomic layer deposition (ALD) to fabricate an anode that prevents or minimizes coking. The research is focused on investigating the activation effect of overpotential on NG conversion and the size-sensitivity of Ni on methane adsorption and carbon deposition.
Advanced combustion approach: NGL-flexible IC engine or turbine operation needs to avoid combustion issues such as flashback, blow out, instabilities, or autoignition. The use of detailed chemical kinetic mechanisms that accurately describe the combustion properties of multi-component C1-C5 hydrocarbon blends representative of NGL-rich gas would help solve these issues. But despite the large number of studies on NG flame behavior or global combustion effects for single, binary, or ternary gas mixtures. WVU researcher Dumitrescu focus on quantifying every important initial, boundary, and operation condition, including using optical diagnostics to measure flame parameters believed to have strong effects on combustion stability, efficiency, and emissions.