Impacts of Heating Rate and Reaction Atmosphere on the Calcination Process
| dc.contributor.advisor | Nathan, Gus | |
| dc.contributor.advisor | Chinninci, Alfonso | |
| dc.contributor.advisor | Dally, Bassam (King Abdullah University of Science and Technology) | |
| dc.contributor.author | Eyad, Al Smadi | |
| dc.contributor.school | School of Electrical and Mechanical Engineering | en |
| dc.date.issued | 2023 | |
| dc.description.abstract | Calcination is a process of mineral ores reduction using thermal energy, and it accounts for a large portion of energy cost and carbon emission. The energy cost of the calcination process is significantly influenced by the size of the reactor, known as the calciner, which, in turn, is directly impacted by the reaction rate and activation energy. Additionally, the utilization of steam as a calcination medium has the potential to reduce energy costs by lowering the heat requirement for carbonates through the elimination of fuel-related carbon emissions and facilitating direct carbon capture. This study aims to identify processes that lower the cost of decarbonization, specifically using steam as a calcination medium, while simultaneously exploring potential factors that reduce the energy cost of the calcination process. An experimental campaign to quantify the calcination rate within a high heating rate environment that aligns with industrial practices was conducted. A bed of fine particles was subjected to thermal treatment using radiant heating at 50 kW/m2. The particle size distribution was 75 μm - 1000 μm and the temperatures were varied from 760 °C to 1212 °C. Both the differential iso-conversional and non-isothermal models were employed and contrasted to determine the impact of heating on reaction rate constant and activation energy. The results highlight the significant impact of heating rate on the calcination kinetics of limestone, gibbsite, and magnesite. It was found that the activation energy for samples calcined at heating rates on the orders of 100 °C/s is 56% lower than that for heating rates < 1 °C/s. it was also observed that samples subjected to calcination at similar temperatures and higher heating rates exhibit an increase in specific surface area (SSA). This phenomenon can be attributed to the presence of microfractures, resulting in decreased activation energy and increased surface area-tovolume ratios, thus accelerating the conversion process. A process modelling study focused on the development and analysis of a novel process to capture carbon during the calcination utilizing a steam-based atmosphere. The novelty of this process is a method to achieve calcination in steam using the byproducts of hydrogen and oxygen combustion, along with recycled steam, to facilitate carbon dioxide capture by condensing the steam from the exhaust gases. The proposed process avoids the need for the high cost of carbon dioxide separation from fossil fuel combustion products. A comparative analysis was conducted between the results of this process and a standard calcination cycle that uses fossil fuels and incorporates carbon capture through oxyfuel combustion. Aspen Plus model was used to evaluate the effectiveness of the new approach. It was found that up to 99% of carbon dioxide can be captured, and 91% of steam can be recycled. This innovative method results in negligible energy cost, apart from the compression unit, which is essential in all carbon capture technologies. A techno-economic analysis revealed that cost parity is achieved between the proposed approach and the oxyfuel route when the price of hydrogen falls within the range of US$1/kg to US$2/kg, relative to the current and projected price of natural gas. | en |
| dc.description.dissertation | Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Mechanical Engineering, 2024 | en |
| dc.identifier.uri | https://hdl.handle.net/2440/141625 | |
| dc.language.iso | en | en |
| dc.provenance | This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals | en |
| dc.subject | Kinetics | en |
| dc.subject | Calcination | en |
| dc.subject | Carbonate | en |
| dc.subject | Heating rate | en |
| dc.subject | Decarbonation | en |
| dc.subject | Steam | en |
| dc.subject | Carbon Capture | en |
| dc.title | Impacts of Heating Rate and Reaction Atmosphere on the Calcination Process | en |
| dc.type | Thesis | en |
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