Enhanced Methane Conversion Via Improved Dry Reforming Catalysts and on-Line Optimization

Authors: 
Praserthdam, S., Texas A&M University
Balbuena, P. B., Texas A&M University
Besides the direct use of methane from natural gas to generate electricity, the conversion via the dry reforming process (DRR) to produce syngas is one of the cost-effective routes for natural gas utilization. Here we report an improved optimization component which can be applied to an on‑line optimization in the DRR. This optimization approach is demonstrated as a two-step procedure: catalyst identification and optimization. The ratings concept proposed as the DRR computational catalyst evaluation tool was employed to identify the catalyst’s reactivity and stability. Each catalyst is given unique reactivity and stability ratings as (RT‑S, RT‑R) indexes based on its activation energy obtained from density functional theory. These indexes characterize the catalyst ability to (1) activate reactants (CH4 and CO2) and (2) form and remove coke compared to the reference catalyst. The indexes are located on the reactivity and stability surface to predict DRR and coking rates at chosen operating conditions. The coking boundary proposed in the concept is used to determine coke‑resistant DRR catalysts, where to meet the acceptable criteria catalysts indexes must be in the coke‑removal zone possessing a higher rate of coke removal than formation. The extended ratings concept expands its application to incorporate the experimental apparent activation energy to abovementioned indexes. Next step is to generate the database for DRR and coke formation/removal rates of a chosen catalyst at different operating temperatures and CO2/CH4 feed ratios. This information is incorporated into the on‑line optimization. The goal is to achieve the conditions where for given changes in methane concentration from the source (e.g., from flue gas) the reaction rate in the reactor can be sustained.

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