Abstract
Coal plays a significant role in electricity production worldwide and will into the foreseeable future. Technologies that improve efficiency and lower emissions are becoming more popular. High pressure reactors and oxyfuel combustion can offer these benefits. Designing new reactors effectively requires accurate single particle modeling. This work models a high-pressure, high-temperature, high-heating rate, entrained-flow, char oxidation data set to generate kinetic parameters. Different modeling methods were explored and a sensitivity analysis on char burnout was performed by varying parameters such as total pressure, O2 partial pressure, O2 and CO2 mole fractions, gas temperature, diameter, and pre-exponential factor. Pressure effects on char burnout modeling were found to be dependent on the set of kinetic parameters chosen. Using kinetic parameters from Hurt-Calo (2001) as opposed to values obtained from Niksa-Hurt (2003) yielded a trend seen in real data sets, that reaction order changes with temperature. Varying O2 mole fraction and partial pressure showed the most significant changes in char burnout. Varying diameter, total pressure, the pre-exponential factor, CO2 environment, and gas temperature all changed the char burnout extent as well. The effect of changing those parameters decreases in the order they are listed. Increasing any of these parameters resulted in an increase in char burnout except for particle diameter and CO2 mole fraction which led to a decrease. Char formation pressure affects reactivity, and a peak in reactivity is shown in this work at the 6 atm condition.
Degree
MS
College and Department
Chemical Engineering
Rights
https://lib.byu.edu/about/copyright/
BYU ScholarsArchive Citation
Gundersen, Daniel, "Modeling of High-Pressure Entrained-Flow Char Oxidation" (2022). Theses and Dissertations. 9726.
https://scholarsarchive.byu.edu/etd/9726
Date Submitted
2022-11-15
Document Type
Thesis
Handle
http://hdl.lib.byu.edu/1877/etd12564
Keywords
char oxidation modeling, high pressure, sensitivity analysis
Language
english