https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33519 Wed 14 Nov 2018 14:00:23 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37826 Wed 12 May 2021 09:25:37 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32694 Wed 11 Jul 2018 15:33:23 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:25467 Wed 11 Apr 2018 11:56:06 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46027 3/CaO-CaCl₂. In the charging process of the PCCaL-TES system, surplus energy is stored via sensible heat, latent heat, and chemical energy with the calcination and melting of the solid solution CaCO₃/CaO-CaCl₂. In the discharging process, the carbonation and solidification of CaCO₃/CaO-CaCl₂ takes place and thus the stored energy is retrieved. Compared to the conventional CaL-TES system, the innovative PCCaL-TES system can help maintain a high activity of CaO over long-term operation due to the enhanced heat and mass transfer in the liquid-state carbonation. In this study, the energy storage performance of PCCaL-TES was assessed using the simulation package Aspen Plus v10. According to the modeling results, the PCCaL-TES system can achieve a round-trip efficiency of up to 49% and an energy storage density of nearly 1.5 GJ/m³, presenting improvements of about 4% and 20%, respectively, compared with the conventional CaL-TES system. Meanwhile, a parametric analysis was carried out to examine the effect of key operating parameters on the system performance of PCCaL-TES. The calculations show that the round-trip efficiency of the PCCaL-TES system can be improved by raising the mole fraction of CaCl₂, increasing the carbonator temperature, or employing an optimum carbonator pressure. It was also found that a low mole fraction of CaCl₂, a high activity of CaO, or a low temperature of CO₂ storage was beneficial to achieving a high energy storage density. Finally, the impact of other operating factors on the round-trip efficiency of PCCaL-TES was summarized in a sensitivity analysis. It revealed the round-trip efficiency of the PCCaL-TES system was dominantly determined by the performance of the CO₂ turbine (W-TURB) and compressor (W-COMP), the gas–liquid heat exchanger (HX3) and the exhaust CO₂ cooler (CL3).]]> Wed 09 Nov 2022 15:45:05 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34925 Wed 05 Aug 2020 13:27:19 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33986 -1 and 295.8 min^-1 kPa^-1. The same methodology for reaction mechanism determination was carried out for the calcination reaction and G(x)=1-(1-x)^1/3 was found to have the best linear fit. The activation energy and pre-exponential factor determined for the calcination reaction were 103.6 kJ mol^-1 and 6.9 × 10⁶ min^-1, respectively.]]> Wed 04 Sep 2019 12:16:35 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:54535 Tue 27 Feb 2024 20:41:10 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34922 Tue 21 Mar 2023 16:12:47 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34809 Tue 14 May 2019 10:49:16 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34546 Tue 09 Mar 2021 12:01:53 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:32404 Thu 31 May 2018 09:12:12 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:19312 600 °C). Proximate analyses indicated near complete devolatilization was apparent at 800 °C for both mines, with thermogravimetric analysis (TGA) revealing that peak devolatilization occurred at 455 °C for Mine A and 467 °C for Mine B. A substantial increase in surface area with increasing pyrolysis temperature was observed for Mine A chailings from 2.7 m²/g at 400 °C to 75.3 mm²/g at 800 °C, because of the presence of microporosity, while Mine B chailings decreased from 2.4 m2/g at 400 °C to 1.2 mm²/g at 800 °C, which was attributed to macroporosity and aggregation of particles. Properties of high-temperature (>600 °C) chailings, namely, surface area, porosity, and pH offer promise for future investigations regarding the application of chailings to soil.]]> Sat 24 Mar 2018 07:51:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26212 Sat 24 Mar 2018 07:36:32 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30699 2 partial pressure (0.05 to 0.1 %), pertinent to a novel greenhouse calcium looping process. The kinetic parameters were obtained and compared with those reported in the literature. Various gas–solid reaction mechanisms were considered to determine the best reaction mechanism for the carbonation reaction. The diffusion function, or G(x)=x², had the best least-squares linear fit, which resulted in a first-order reaction for the carbonation reaction in the greenhouse calcium looping process. Moreover, the activation energy and pre-exponential factor of the carbonation reaction were established to be 19.7 kJ mol⁻¹ and 295.8 min⁻¹ kPa⁻¹, respectively. The derived kinetic parameters were used in Aspen Plus to optimize the carbonator reactor size. The required size of the reactor decreased with increasing operating temperature of the reactor. Exergy analysis revealed that the overall exergetic efficiency of greenhouse calcium looping could be more than 80 %.]]> Sat 24 Mar 2018 07:35:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26078 ex situ tar removal unit, where tar cracking is expected to occur via catalytic reactions with CaO. The current work evaluates the feasibility of the proposed CL-BIGCC concept via thermodynamic analysis using Aspen Plus. Moreover, the tar cracking ability of CaO is demonstrated using thermogravimetric analyzer coupled to Fourier transform infrared spectrometer (TGA-FTIR) experiments. As part of the thermodynamic analysis, sensitivity analyses of the key process parameters, such as the calcium/biomass (Ca/B) ratio, steam/biomass (S/B) ratio, carbonator temperature, and calciner temperature, and their effects on net thermal-to-electricity efficiency have been studied in detail. The optimal values of key process parameters, such as a compression ratio of 5.1, an air/fuel mass ratio of 15, a Ca/B ratio of 0.53, a S/B ratio of 0.17, and carbonator and calciner temperatures of 650 and 800 °C, respectively, have been obtained. Furthermore, the CL-BIGCC process simulated in the current work was found to have a net thermal-to-electricity efficiency of ~25% based on the above optimal parameters, which is the highest among other conventional steam-based BIGCC processes. The biomass gasification (i.e., partial oxidation) experiments in a TGA-FTIR with a CaO/biomass ratio of 1:1 at different temperatures showed that CaO effectively catalyzed tar-cracking reactions.]]> Sat 24 Mar 2018 07:31:31 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:53276 Mon 29 Jan 2024 18:25:41 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44056 2CO₃: 43.5%, Na₂CO₃: 31.5%, K₂CO₃: 25% mol), subjected to two different higher heating temperatures (350 °C and 600 °C). It is shown here that the addition of a carbonate eutectic affects char-making reactions through: tar generation modification, changes in the emitted volatile molecules, alteration of surface oxygenate bonds as well as transformation in the morphology of the remnant char. Initial results using Differential Thermal Gravimetric Analysis (DTG) show that, in carbonate treated samples, char yield is increased at both temperatures investigated. In treated cellulose, a reduced temperature onset of mass loss is observed, expected to be from modified depolymerisation and inhibition of levoglucosan formation for samples heated to both 350 °C and 600 °C. Gas analysis by micro-GC proves that carbonate is involved in the cracking of condensable volatiles, which generates a highly porous char structure and increases the emission of non-condensable volatiles. In addition, SEM results for carbonate treated cellulose demonstrate extensive pore generation including both surface and internally generated pores and interconnected tunnel-like structures at higher temperature (600 °C). This was not reflected however in BET results due to the melted salt blocking the available internal porous structure. Improvement in BET results for chars produced at 600 °C was regardless seen on carbonate addition in both biomass (improving from 371 m² g⁻¹ to 516 m² g⁻¹) and lignin (improving from 11 m² g⁻¹ to 209 m² g⁻¹).]]> Mon 29 Jan 2024 17:46:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47208 Mon 29 Jan 2024 17:45:48 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47525 Mon 23 Jan 2023 12:15:50 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29902 2 and CO, attributed to the tar cracking abilities of slag.]]> Fri 31 May 2019 12:33:49 AEST ]]> 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 ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:46145 Eucalyptus pilularis biomass and ternary molten carbonate eutectic [Li₂CO₃, 43.5%; Na₂CO₃, 31.5%; and K₂CO₃, 25% (mole percentage)] in thermogravimetric analysis at three different temperatures, 600, 750, and 900 °C, was studied. These salts affect the slow pyrolysis process, including changes in the volatile release mechanism and the morphology of remnant char material. The initial results show that, in the presence of molten carbonate, biomass particles make bubble-shaped larger particles, which result in less volatile emissions and more char residue. It is suggested that the ternary eutectic has a chemical diluent and catalytic role, particularly in the case of higher salt doping. Results from scanning electron microscopy images give strong evidence that molten carbonates capture volatiles inside swelling carbon particles, which causes the generation of various sizes of pores as well as char-making reactions, and at a higher temperature, the bubble-shaped particles will rupture. Swelling of this nature has previously only been observed clearly in coal precursors; however, this is the first observation in a biomass-based system. Also, at a temperature above 750 °C, decomposition of molten carbonate generates CO₂ and carbon/carbonate gasification produces CO as well as a more “activated” biochar.]]> Fri 11 Nov 2022 18:31:02 AEDT ]]>