(640c) Iron-Based Chemical Looping Biomass Gasification for Carbon Nanofiber Production: Process Simulation and Experiments

Carbon nanofibers (CNFs) are widely used in multiple industrial areas such as electrochemistry, catalysis, material manufacture, etc. Nowadays, researches are intensively focused on developing cost-effective and environmentally friendly pathways to produce high-quality CNFs. The Ohio State University (OSU) has been collaborating with Applied Science Inc. (ASI) to investigate a chemical looping based pathway for low-cost production of CNFs as a replacement for high grade carbon black. The pathway under investigation consists of two consecutive steps: chemical looping biomass to syngas (BTS) process developed by OSU and syngas to CNFs conversion process developed by ASI. The synergistic combination of the two processes enables the conversion of a clean and renewable raw material, woody biomass, into a value-added product via an energy- and cost-efficient pathway, substituting the use of natural gas as the feedstock in conventional processes. This study includes simulation and experimental works. ASPEN Plus is utilized to simulate the OSU BTS process with respect to the operating conditions including temperature, oxygen carrier/fuel feed ratio and H₂O, CO₂ feed rates and their influence on the syngas composition. Syngas with various H₂/CO ratio and CO/CO₂ ratio based on simulation results will then be injected into CNF reactors at ASI to synthesize CNFs and compare the product performance under different operating conditions including syngas feed composition, temperature and the use of microwave. It is shown from simulation that OSU BTS process is able to produce a flexible H₂/CO ratio ranging from 0.4 to 2. Preliminary experiments conducted at ASI under various temperature and feedstock inputs have shown a mass yield of 19% using CO as the main feedstock, higher than the 16% yield achieved using CH₄ as the feedstock in conventional processes. Additionally, CNFs produced from CO shows a ~10 times increase in specific volume compared to CNFs produced from natural gas, CH₄, suggesting that the CNFs produced from CO could be smaller in diameter and better-ordered. Further experiments will be conducted using CO, CO2 and H₂ at different concentration as the feedstock to investigate their impact on CNF yield and quality. In conclusion, the combination of OSU BTS and ASI CNF production process shows a significant improvement over the traditional technologies by lowering cost, enhancing carbon conversion efficiency, reducing CO₂ emissions and has significant market penetration potential.