Session: 11-01 Carbon Capture and Sequestration

Paper Number: 114726

114726 - Natural Gas to Chemical Intermediate by Highly Efficient Carbon-Neutral Route 

Aromatics, like benzene, toluene, and xylenes, are the essential building blocks for some of the largest petrochemical products in today’s use. The vast majority (97%) of today’s aromatics production relies on crude oil in the first place. Supply of aromatics mainly hinges on three different sources: steam cracking of naphtha, catalytic reforming, and coke-oven light oil (COLO). All three processes require the production of significant amounts of synthesis gas, in turn creating significant amounts of carbon dioxide and produce high capital and production cost. Methane (CH₄), the main component of natural gas, has the highest hydrogen (H) -to- carbon (C) ratio of all hydrocarbons; therefore, it is more environmentally friendly in terms of carbon dioxide (CO₂) emissions than oil or coal-derived fuels. Furthermore, North America and methane hydrate in the sediments of the ocean floors, which are conservatively estimated to represent twice the amount of carbon in all other known fossil fuel reserves. An efficient methane dehydroaromatization (MDA) catalyst should i) effectively activate stable C–H bonds in CH₄ molecules, ii) allow selective production of light aromatics, minimizing the formation of unwanted graphitic carbon (coke), and iii) remain stable at high reaction temperature.

We chose two directions to achieve the objectives. First, we designed a new ternary catalyst in a fixed-bed reactor (FBR)—Mo-based catalyst using bimetallic platinum (Pt) – Bismuth (Bi) as promoter that shows 25% increased methane conversion ratio compared to conventional Molybdenum (Mo)-based catalyst, and a higher yield to benzene at higher CH₄ conversions (approximately 14.2% with conversion of 20.4%, equal to 1272 mL·gcat⁻¹·h⁻¹). In addition, Mo-based catalyst with platinum (Pt) – Copper (Cu) bimetallic alloy was integrated with a proton-conducting fuel cell to co-generate aromatics and electricity with its remarkable performance. It presents a 20% increased single-pass methane conversion and 13% benzene relative selectivity compared to FBR, as well as high output power density of 275 mW·cm⁻² in CH₄ at 700 °C.

Presenting Author: Pengxi Zhu George Mason University

Presenting Author Biography: Pengxi Zhu is a PhD student in the Department of Mechanical Engineering, George Mason University. He obtained his BS in Microelectronics from Jilin University and his MS in Electrical Engineering from Stevens Institute of Technology. Right now he as a graduate research intern works in Dong Ding's group of Idaho National Laboratory. His research focuses on catalyst fabrication and testing, electrocatalysis, proton conducting fuel cell fabrication and electrochemical testing.