An investigation on plant cell walls during biomass pyrolysis: A histochemical perspective on engineering applications

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Siliceous foam material and its application in post-combustion carbon capture for NGCC plants: effects of aging conditions

In an effort to reduce the overall energy penalty and capital expenditure associated with carbon capture technologies, a variety of porous solid adsorbents have been developed. The limitations of solid sorbent in large-scale process are related to its CO2 uptake, physicochemical stability, lifecycle, regenerability and operation condition. In this paper, siliceous foam materials were synthesized via a modified microemulsion templating method and functionalized with branched polyethylenimine (PEI). The physical characteristics of synthesized silica adsorbents under different aging conditions were analysed via N2 sorption analysis and Scanned Electron Microscopy (SEM) morphological analysis. CO2 uptake was evaluated by thermogravimetric analyser (TGA). The results show that CO2 uptake is desirable even under low CO2 partial pressure and is predictable with multiple linear regression (MLR) model in the range of examined materials

The Influence of Mineral Addition on the Optimised Advanced Ash Fusion Test (OAAFT) and its Thermochemical Modelling and Prediction

Specific minerals in ash are triggers for ash fusion during combustion. This study analyses, for the first time, the link between individual minerals and the ash fusion of pseudo ash pellets using the Optimised Advanced Ash Fusion Test (OAAFT) and FactSage modelling. The study analysed 20 pseudo ash pellets whose composition spanned a wide range of fuels used in the power generation industry. Varying quantities of the 4 main minerals were used to create the pseudo pellets; CaO (0–40%), Fe2O3 (0–40%), MgO (0–25%), and Silica-Alumina ratio (0.5:1–4:1). The OAAFT produced characteristic ash fusion curves for the pseudo pellets and individual minerals. The study also gained insight into the link between mineral transformations and ash fusion by comparing these profiles to the slag formation predictions in the FactSage modelling. Excellent alignment was obtained between the OAAFT curves and FactSage data. The OAFFT curves can be described as individual fingerprints of the ash fusion behaviour of the sample, which can be broken down into individual components. This data cannot be obtained from the conventional ash fusion test. By combining OAAFT and FactSage data, power generators can replicate slagging and fouling issues and identify the major components which are causing issues. The addition of mineral additives can be tested to analyse how slagging and fouling issues can be tackled for specific fuels. This will be of increasing importance as fuel blending and new complex fuels such as refuse derived fuels enter the market

The impact of ash pellet characteristics and pellet processing parameters on ash fusion behaviour

The Ash Fusion Test (AFT) is considered to be the most popular method of characterising the melt characteristics of solid fuel ash. This study shows how pellet preparation can make significant improvements to repeatability. Pelleting pressure, pellet particle size, pellet shape, and furnace ramp rate were investigated to establish the most repeatable representation of ash melting relevant to pulverised fuel combustion in a furnace in an oxidizing atmosphere up to 1600 °C. A 5 mm machine pressed pellet was found to produce the best results as it identified the earliest initial deformation temperature (IDT), gave the least error, and displayed the greatest visible change in pellet height to enable easy identification. Reducing maximum ash particle size to <72 µm and increasing the pressure of the pelleting process was also shown to produce a 120 °C reduction in the IDT when compared with other methods. Reducing the ashing temperature and retaining volatiles lost during high temperature ashing were shown to have a negligible impact on IDT. The characteristic AFT curve was also used to quantify the extent of shrinkage and swelling during the test

Screening of metal oxides for Hg0 capture

Fossil fuel related industriesare the major anthropogenic sources of Hg0 emission. Due to awareness of the detrimental impact, there is an increasing interest in discovering potential materials for Hg0 removal. In this paper, the first-row transition metals (from V to Zn), Mo and rare earth metals (La and Ce) in the oxidation states supported by γ-Al2O3werepreparedand studied as potential candidates for Hg0 capture. Based on evolution of the parameters of enthalpies (ΔH), Gibbs free energy (ΔG), adsorption peaks (Ta, peak), maximumHg0 capture efficiencies (μmax) and activation energy (Ea)etc, the samples of Cr, Ni, Fe, Mn, Co, Ce and Cu showed better performancesfor Hg0 capture amongst the 11 metal oxides. The results also indicated that MoO3 has potential to promote Hg0 capture since the activation energy is relatively low. Consequently, most of the Mo-based binary metal oxides have relatively high Hg0 removal efficienciescoupled with lowactivation energies. Particularly, the binary metal oxides of CrMo, MnMo, CuMo, CeMo andCoMo could be selected as appropriate candidates for Hg0 capture within specifictemperature windows

CO2 gasification and pyrolysis reactivity evaluation of oil shale

This research focuses on the non-isothermal CO2 gasification and pyrolysis reactivity via thermogravimetric analysis. It was found that CO2 decreased activation energy of all four types of oil shale (Fushun, Jinzhou, Wulin, Xingsheng). Activation energy of XS oil shale was highly reduced from 59.86 kJ/mol to 9.48 kJ/mol. Reactivity index results showed that WL and XS oil shales were observed to be more dependent on CO2 atmosphere. Alkali metal oxide also contributed to thermal decomposition according to thermogravimetric (TG) and differential thermal analysis (DTG) curves during CO2 gasification process. Overall, CO2 atmosphere can be used to improve oil shale decomposition, especially for alkali- rich shales, while providing an efficient and effective means to convert greenhouse gases into useful fuels. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy

The kinetics studies and thermal characterisation of biomass

This work aims to investigate and develop a method to evaluate and predict the combustion behaviour and combustion efficiency of different biomass commonly used in power plants via simple characterisation methods. 11 types of agricultural and industrial wastes were characterised using thermogravimetric analyser to obtain the derivative thermogravimetric (DTG) data and kinetic parameters. For the samples tested, the initiation temperatures were found to be in the range between 224.39 0 C and 260.33 0 C, whilst the local minimum temperatures between 2 peaks were within the range of 360.36 to 382.74 0 C. It was established that there is a clear, direct relationship between the pre-exponential factor and the temperature interval for the first step of combustion. This trend was apparent and recorded for the 2 heating rates tested. © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of ICAE2018 - The 10th International Conference on Applied Energy

The COVID-19 vaccines: recent development, challenges and prospects

The highly infectious coronavirus disease 2019 (COVID-19) associated with the pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to become a global pandemic. At present, the world is relying mainly on containment and hygiene-related measures, as well as repurposed drugs to control the outbreak. The development of COVID-19 vaccines is crucial for the world to return to pre-pandemic normalcy, and a collective global effort has been invested into protection against SARS-CoV-2. As of March 2021, thirteen vaccines have been approved for application whilst over 90 vaccine candidates are under clinical trials. This review focuses on the development of COVID-19 vaccines and highlights the efficacy and vaccination reactions of the authorised vaccines. The mechanisms, storage, and dosage specification of vaccine candidates at the advanced stage of development are also critically reviewed together with considerations for potential challenges. Whilst the development of a vaccine is, in general, in its infancy, current progress is promising. However, the world population will have to continue to adapt to the “new normal” and practice social distancing and hygienic measures, at least until effective vaccines are available to the general public

The data-intensive scientific revolution occurring where two-dimensional materials meet machine learning

Machine learning (ML) has experienced rapid development in recent years and been widely applied to assist studies in various research areas. Two-dimensional (2D) materials, due to their unique chemical and physical properties, have been receiving increasing attention since the isolation of graphene. The combination of ML and 2D materials science has significantly accelerated the development of new functional 2D materials, and a timely review may inspire further ML-assisted 2D materials development. In this review, we provide a horizontal and vertical summary of the recent advances at the intersection of the fields of ML and 2D materials, discussing ML-assisted 2D materials preparation (design, discovery, and synthesis of 2D materials), atomistic structure analysis (structure identification and formation mechanism), and properties prediction (electronic properties, thermodynamic properties, mechanical properties, and other properties) and revealing their connections. Finally, we highlight current research challenges and provide insight into future research opportunities.This work was supported by the ANU Futures Scheme (Q4601024), the Australian Research Council (DP190100295, LE190100014), the National Natural Science Foundation of China (No. 51706114 and 51302166), Functional Materials Interfaces Genome (FIG) project, and Doctoral Fund of Ministry of Education of China (20133108120021)

Synthesis of graphene: potential carbon precursors and approaches

Graphene is an advanced carbon functional material with inherent unique properties that make it suitable for a wide range of applications. It can be synthesized through either the top–down approach involving delamination of graphitic materials or the bottom–up approach involving graphene assembly from smaller building units. Common top–down approaches are exfoliation and reduction while bottom–up approaches include chemical vapour deposition, epitaxial growth, and pyrolysis. A range of materials have been successfully used as precursors in various synthesis methods to derive graphene. This review analyses and discusses the suitability of conventional, plant- and animal-derived, chemical, and fossil precursors for graphene synthesis. Together with its associated technical feasibility and economic and environmental impacts, the quality of resultant graphene is critically assessed and discussed. After evaluating the parameters mentioned above, the most appropriate synthesis method for each precursor is identified. While graphite is currently the most common precursor for graphene synthesis, several other precursors have the potential to synthesize graphene of comparable, if not better, quality and yield. Thus, this review provides an overview and insights into identifying the potential of various carbon precursors for large-scale and commercial production of fit-for-purpose graphene for specific applications