https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46263 2 emissions per unit energy generation. They represent some of the primary and intermediate solutions to the world’s energy security. Extensive numerical modeling efforts have been undertaken over the past several decades, which have increased our understanding of the technical problems in HELE boilers, including combustion and boiler performance optimization, ash deposition, and material problems at higher operating temperatures and pressures. Overall, the differences in the physical and chemical models, boiler performance, and ash deposition of oxy-fuel combustion in HELE boilers that recirculate CO₂ and H₂O in the boilers are also discussed in comparison with the combustion of coal in the air. This Review comprehensively summarizes the current research on numerical modeling to offer a better understanding of the technical aspects and provides future research requirements of HELE coal-fired boilers, including boiler performance optimization, ash deposition, and material problems. The effects of changes in the configuration and operating conditions are discussed, focusing on the optimization of boiler performance in aspects such as unburnt carbon and NOx emissions. The paper also reviews the retrofit and optimization of operating conditions and the burner geometry with the low-NOx coal combustion technologies necessary to operate the HELE power plants. In terms of ash deposition, the development of submodels, including particle sticking and impacting behaviors and their effects on the deposit growth predictions under different temperatures, are discussed. Numerical models of the material oxidation and creep in the austenitic and nickel-based alloys generally used in HELE conditions have been developed using the finite element method to predict the availability of advanced alloys and creep life in the actual service time of the boiler parts. The predictions of oxide scale growth and exfoliation on the steam-side and fire-side and the creep strength are analyzed. The review also identifies some further research requirements in numerical modeling to achieve the optimization of coal combustion processes and address the technical problems in advanced HELE power plant operations.]]> Tue 15 Nov 2022 08:05:43 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:12285 Sat 24 Mar 2018 08:10:11 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38020 3). CaO is then used to simultaneously oxidize VAM (methane concentrations of 0.1–1 vol % in air) and capture carbon dioxide (CO₂) produced to form CaCO3. The two cycles can be performed in a single reactor, or the process can be performed continuously in dual interconnected reactors. Preliminary experiments on the SDL process have previously been performed at laboratory scale. In this study, further laboratory-scale studies were conducted in conjunction with pilot-scale SDL investigations in a single 1 m³/s fluidized bed reactor. The effect of inventory size (1–2 tonnes of CaCO₃), operating temperature (565–700 °C), and flow rate (1–1.7 m³/s) on methane conversion was investigated. At temperatures of 600 °C and above, >99.5% methane conversion was achieved for all inventory sizes and flow rates examined. At temperatures of 565 and 575 °C, 41 and 70% methane conversions were achieved, respectively. VAM fluctuation experiments were performed, and it was shown that a fluid bed can act as a thermal mass to reduce fluctuations in the bed temperature as the VAM concentration changes.]]> Fri 23 Jul 2021 15:47:37 AEST ]]>