(298b) Dual Production of Higher Hydrocarbons and Syngas from Greenhouse Gases in a Hydrogen-Permeable Membrane Reactor

CH₄ and CO₂ are the largest anthropogenic greenhouse gas (GHG) contributors to climate change. Due to the abundance of natural gas, CH₄ will be increasingly utilized for both energy and chemical production with potentially even greater GHG emissions unless methods are developed to increase the efficiency of CH₄ conversion, ideally by non-oxidative (no CO₂ production) processes. In this talk, we present the first ever direct non-oxidative methane conversion (DNMC) with CO₂ to produce value added C₂₊ hydrocarbons in an integrated DNMC-catalyst/hydrogen-permeable-membrane reactor. Specifically, a direct utilization of CH₄ and CO₂ to simultaneously produce C₂₊ hydrocarbons (C₂ and aromatics) and syngas (CO and H₂) on opposite sides of a mixed ionic-electronic conducting SrCe_0.7Zr_0.2Eu_0.1O_3-δ membrane reactor will be discussed. On one side (interior) of the membrane reactor, direct non-oxidative methane conversion (DNMC) over an iron/silica catalyst produces C₂₊ hydrocarbons and H₂. On the other side (outer surface) of the membrane, permeated hydrogen (driving the DNMC reaction) reacts with a CO₂ sweep gas to form CO and water via the reverse water gas shift (RWGS) reaction. This novel single hydrogen-permeable membrane reactor simultaneously addresses both reduction of greenhouse gas (CO₂ and CH₄) emissions as well as production of value-added hydrocarbon products (C₂₊, CO, and H₂) with in situ gas separation. This membrane reactor not only circumvents gas-to-liquid (GTL) thermodynamic limitation of CH₄ conversion to C₂₊ hydrocarbons (without producing byproduct CO₂) but in fact uses CO₂ as a sweep gas to react with the permeated hydrogen to form CO as a feedstock for additional GTL reactions, thus simultaneous producing value added chemicals while reducing GHG emissions.