Date of Graduation
1986
Document Type
Thesis
Abstract
A plausible explanation of biomass pyrolysis at high temperature is here-in developed. A combination of techniques was used. Pyrogas Chromatograph (PGC) and Gas Chromatograph-Mass Spectrometer (GCMS) were used to study the effluent gases of pyrolysis. Thermo-Gravimetric Analysis (TGA) was used to study the decomposition rate of biomass. The analysis of the effluent gases of cellulose, hemicellulose, lignin, and biomass samples indicate that the secondary reactions (gas-gas and solid-gas phase reactions) play an important role in the final distribution of the pyrolytic products of biomass. The TGA study of the three components indicate that each component displays a different thermal behavior. Hemicellulose is the least stable component and volatilizes faster than cellulose and lignin. Lignin produces more char. The structure of the cell wall was reviewed to understand the morphology of the three components of biomass within the cell wall and help explain pyrolysis. The wood cell consists of cellulose, hemicellulose, and lignin. Lignin is the major constituent of the middle lamella which binds the cells together. Cellulose fibers are embedded in hemicellulose matrix which are encrusted in lignin. The following plausible pyrolysis explanation of biomass may be suggested: as biomass is heated, the thermally most sensitive component starts to break down. Hemicellulose starts to decompose at a relatively lower temperature undergoing rapid decomposition. Cellulose and lignin decomposition starts at a relatively higher temperature. Lignin volatilizes at a slower rate, therefore it takes a longer time for lignin to break down. The volatile products of cellulose and hemicellulose become entrapped within the cell until lignin decomposes and loosens the bind around the cell wall. The volatile products constrained within the morphological cell react under the initial high pressure in the cell before they travel through the lignin char matrix to escape from the system. The hot char matrix and the impurities in biomass serve as a catalyst for further char-gas and gas-gas reactions. Based on the present work, it is therefore concluded that due to the secondary reactions, the response of the lignocellulosic materials to pyrolysis is not the simple superposition of responses of the individual components.
Recommended Citation
Usmen, Rengin Kadriye, "A Plausible Explanation Of Biomass Pyrolysis At High Temperature (Pyro Gas-Chromatograph, Cellulose, Lignin, Wood, Thermogravimetric Analysis)." (1986). Graduate Theses, Dissertations, and Problem Reports. 9930.
https://researchrepository.wvu.edu/etd/9930