Abstract
Thermogravimetric analysis was conducted on two sets of solid fuels to observe trends in combustive behavior. The introduction provides descriptions of the equipment used to conduct experiments and theory for solid reactions. Chapters 2 and 3 are conference papers submitted to The Combustion Institute, and their results were presented at the 2018 Western States Section of the Combustion Institute meeting and the 11th US National Combustion meeting, respectively.
The conference paper in Chapter 2 titled Combustion of Graphite Nanoparticles with Copper (II) Oxide in a Thermogravimetric Analyzer with Evolved Gas Analysis describes procedures of and results from experiments performed on the caron/graphite mixture with respect to increasing temperature. While samples were heated from room temperature to 975°C exhaust from the TGA furnace was purged to a NDIR gas analyzer for quantification of CO and CO_2. Modulated TGA experiments were conducted to find activation energy across the range of temperatures, which were compared with gas evolution and thermogravimetric behavior of the samples subjected to increasing temperature at rates of 5, 10, 15, and 20°C/min. Results show early production of CO leads to a rapid production of CO_2 and the evolution of these gasses are related to the weight lost from solid samples. Peak activation energy values follow peaks in the rate of weight loss, and EDS data showed CuO reduced to Cu in a sigmoidal manner as the temperature increased.
Chapter 3 is the conference paper titled Modulated Thermogravimetric Experiments on Argonne Premium Coal Samples with Combustion Gas Analysis. The eight coal samples provided by the program were subjected to two types of experimentation; modulated TGA tests, and product analysis using a FTIR spectrometer with air as the oxidizer. The modulated TGA experiments were carried out in the temperature range of 20-750°C. The temperature was increased at a rate of 2°C per minute, each test had a superposed temperature modulation with amplitude ±5°C and a period of 200 seconds. The second set of standard TGA tests were conducted in the same temperature range and for a linear ramp rate of 5°C per minute to 750°C. The furnace was purged using air at a rate of 25 mL per minute. The resulting exhaust from the furnace was directed to a FTIR for identification and quantitation of the products of combustion. Weight loss of the solid products correlated to the rank of each coal sample; however higher ranked coals showed pre-combustive weight gain in the range 200-320°C which has been attributed to chemisorption. Similar to experiments described in chapter 2, peak values for the rate of weight loss are related to CO and CO_2 evolution and activation energy. Additional evolved gasses identified by the FTIR spectrometer were methane and aromatic nitro compounds.
Chapter 4 concludes with discussion on CLOU techniques and how they relate to results obtained from chapter 2. In the chapter specific values of temperatures, rates, and percent weight are givend that were omitted from the original papers. The final section purposes further experimentation to enhance the study herein.