Experimental and numerical verifications of new methods to predict gasification kinetics of char from MSW (Municipal Solid Waste) components using the TGA

• Author / Creator

  Baath, Yuvraj Singh

• Thermogravimetric Analyzer (TGA) is a standard state-of-the-art instrument used for investigating char gasification kinetics. However, one major flaw of the TGA is the build-up of a stagnant gas region between the empty space of the crucible mouth and the char sample layer which leads to poor gas-solid contacting. Diffusion is the predominant transport mechanism for the transport of the reactive gas from the crucible mouth to the porous char layer. Therefore, the aim of this work is to present a numerical model for evaluating the kinetic data using a TGA, which encapsulates the three diffusion phenomenons of the reactive gas inside the TGA crucible (i) diffusion of gas between the char layer and crucible mouth, (ii) diffusion of gas within the inter-particle voids of the char layer and (iii) diffusion of the gas within the intra-particle pores of the char particle. The model was first formulated and validated for the non-porous char particles and then extended to the porous particles. Experimentally derived kinetic data was used as initial input for the model and the improved parameters were derived by tuning the model to predict the experimental curves. The consideration of diffusional effects within the crucible resulted in an 8.5 % increase in the activation energy.
  In the second part of this work, chars are formed using the blends of Softwood and High-Density Polyethylene. First, the synergistic effects during the co-pyrolysis of these mixtures are studied using the TGA. It is seen that the synergies between biomass and plastic favor the release of volatiles and reduce the char formation. The synergistic effects also improve the gasification reactivity of the chars by increasing their carbon content and the BET surface area. Finally, the TGA model is used to determine the kinetic parameters of the gasification of these chars. A 3.9% decrease in the activation energy was observed upon increasing the blending ratio of the HDPE from 0 to 50%.

• Subjects / Keywords

  • MSW
  • Biochar
  • TGA
  • Gasification
  • Modeling
  • Reaction kinetics

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-gd2x-7615

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.