| Autor: |
Reyes Molina EA; Forest Biomaterials Department, North Carolina State University, 2820 Faucette Drive, Raleigh, North Carolina27607, United States.; Energy, Environment Science and Technology─Bioenergy Feedstock Technologies Department, Idaho National Laboratory, 750 MK Simpson Boulevard, Idaho Falls, Idaho83415, United States., Soneja R; Forest Biomaterials Department, North Carolina State University, 2820 Faucette Drive, Raleigh, North Carolina27607, United States.; Geospatial Services Department, AYRES Associates Inc., 52011 E. Terrace Drive, Madison, Wisconsin53718, United States., Herrera Diaz M; Forest Biomaterials Department, North Carolina State University, 2820 Faucette Drive, Raleigh, North Carolina27607, United States.; Energy, Environment Science and Technology─Operations Research & Analysis Department, Idaho National Laboratory, 2353 North Boulevard, Idaho Falls, Idaho83415, United States., Tilotta DC; Forest Biomaterials Department, North Carolina State University, 2820 Faucette Drive, Raleigh, North Carolina27607, United States., Kelley SS; Forest Biomaterials Department, North Carolina State University, 2820 Faucette Drive, Raleigh, North Carolina27607, United States. |
| Abstrakt: |
Solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) analysis was used for the at-line sampling of pyrolytic vapors produced during the fast pyrolysis of biomass. The pure and binary blends of switchgrass (SWG) and pine harvest residues (PT6) were used as biomass feedstocks. Sequential SPME sampling allowed for monitoring of changes in the pyrolysis vapors as char accumulated in the fluid bed. The relative concentration and composition of the pyrolysis vapors desorbed from the SPME fibers were investigated using GC-MS, and the resulting chromatograms were analyzed using principal component analysis (PCA) to compare the composition of the pyrolysis vapors over the course of the pyrolysis run. The chemical compositions of both carbohydrate and lignin fragments varied as the char builds up in the reactor bed. Fragments derived from cellulose and hemicelluloses included anhydrosugars, furans, and light-oxygenated compounds. Lignin fragments included methoxyphenols, phenolic ketones, aldehydes, and low-molecular-weight aromatics. The composition of the carbohydrate fragments changed more than those of the lignin fragments as the char built up in the fluid bed. This combination of SPME-GC/MS-PCA was a novel, easy, and effective method for measuring the composition and changes in the composition of pyrolysis vapors during the fast pyrolysis process. This work also highlighted the effect of char build-up on the composition of the overall pyrolysis vapors. |
