Search

Biogas offers significant benefits as a renewable energy source, contributing to decarbonization, waste management, and economic development. This comprehensive review examines the historical, technological, economic, and global aspects of biomethane production, focusing on the key players such as China, the European Union, and North America, and associated opportunities and challenges as well as future prospects from an Australia perspective. The review begins with an introduction to biogas, detailing its composition, feedstock sources, historical development, and anaerobic digestion (AD) process. Subsequently, it delves into major biomethane production technologies, including physicochemical absorption, high‐pressure water scrubbing (HPWS), amine scrubbing (AS), pressure swing adsorption (PSA), membrane permeation/separation (MP), and other technologies including organic solvent scrubbing and cryogenic separation. The study also discusses general guidelines of techno‐economic assessments (TEAs) regarding biomethane production, outlining the methodologies, inventory analysis, environmental life cycle assessment (LCA), and estimated production costs. Challenges and opportunities of biogas utilization in Australia are explored, highlighting and referencing global projections, polarization in production approaches, circularity in waste management, and specific considerations for Australia. The review concludes discussing future perspectives for biomethane, emphasizing the importance of technological advancements, policy support, and investment in realizing its full potential for sustainable energy and waste management solutions. [ABSTRACT FROM AUTHOR]

Recently, salt-assisted pyrolyzation has been deemed an emerging and efficient method for the preparation of biochars due to its facile operation as well as its good structural and chemical properties. In this work, biochars (MBCx) are prepared by heating bamboo powders in eutectic salts (Li2CO3 + K2CO3) at 500–600 °C in the air. Multiple technologies are employed to examine the physiochemical properties of bamboo biochars. Correlations between heating temperature and structural features and carbon dioxide uptakes of bamboo biochars have been investigated. The results show that heating temperature has a significant influence on the physicochemical properties of bamboo biochars. With the elevation of the heating temperature, the defect structures of bamboo biochars gradually ascend, especially when the heating temperature reaches 600 °C. MBCx biochars visibly exceed conventional bamboo biochar prepared via pyrolyzation in a nitrogen stream free of salt addition. Pyrolysis of bamboo in eutectic salts endows biochars with higher oxygen content and more carbon defects, which likely accounts for their better CO2 capture activities. [ABSTRACT FROM AUTHOR]

Modern energy batteries are mainly used in pure electric vehicles. The stability of battery operation relies heavily on thermal management systems for which phase-change batteries have become an effective solution. In this study, we designed a battery thermal management system divided into two parts: a shaped phase-change material (PCM) module and a battery module. In the qualitative PCM module, polyethylene glycol was used to absorb heat, expanded graphite (EG) was used as the thermally conductive agent, and copper foam formed the support skeleton. The battery module comprised an 18650 lithium-ion battery with an enthalpy of 155 J/g. In our experiments, we applied PCMs to the battery modules and demonstrated the effectiveness of composite PCM (CPCM) in effectively lowering the temperature of both battery packs and minimizing the temperature discrepancies among individual batteries. At a gradually increasing discharge rate (1C/2C/3C), the battery's Tmax could be lowered and the temperature could be de creased at various positions. It was evident that the battery temperature could be effectively preserved using CPCM. The findings of this study lay a foundation for future research on battery thermal management. Finally, the copper foam and EG contributed significantly to the prevention of leakage. [ABSTRACT FROM AUTHOR]

Sulfate-induced deterioration can reduce the service life of recycled aggregate concrete (RAC). To demonstrate the transport behavior of sulfate ions in RAC, a two-dimensional, six-phase numerical model of RAC is proposed in this study. Sulfate ion diffusion coefficients were defined for different phases [attached mortar, new mortar, interfacial transition zone (ITZ) between attached mortar and original aggregate, ITZ between the new mortar and original aggregate, and ITZ between the new mortar and attached mortar] of RAC. The effects of ITZ width and porosity on ion transport behavior in RAC were analyzed. The results show that the numerical model agrees with the experimental data. Numerical results indicate that the six-phase model of RAC provides more-accurate simulation results because tortuosity is reflected in the model. The width and porosity of ITZs both affect the diffusion of sulfate ions in concrete. However, due to the low volume fraction of ITZ in concrete, just improving ITZ performance has no significant effect on ion attack resistance of concrete. The ITZ is a crucial zone where damage may originate and develop. [ABSTRACT FROM AUTHOR]

The Cover Feature shows an Australian map highlighting the distribution of operational biogas facilities. Overlaid is a visual representation of the anaerobic digestion process, illustrating the transformation of waste into biomethane. This artwork symbolizes the regional implementation and technological processes reviewed by F. Wang and co‐workers, which emphasizes Australia′s role in advancing renewable energy solutions...By Ross Swinbourn; Chaoen Li and Feng WangReported by Author; Author; Author [Extracted from the article]

Coal burning emits a significant amount of elemental mercury (Hgo) into the atmosphere, which can cause severe damage to the environment and human health. Here, magnetic FeS2 nanorods are facilely obtained via a low-temperature (200–350 °C) molten salt (KSCN) route. The annealing temperature is found to notably affect the structure and Hgo capture performance of FeS2, while precursors exert subtle effects on the mercury adsorption performance. The Hgo capture ability of FeS2 first increases and then decreases with increasing annealing temperature. The highest magnetism (12 emu/g) and optimal mercury capture performance (Hgo removal efficiency of 96.2%) are achieved over FeS2 nanorods synthesized at 250 °C. This material shows superior performance in the temperature range of 60–180 °C owing to its rod-like structure with ample number of exposed adsorption sites. NO and SO2 are found to only slightly intervene in the mercury removal process. Hgo vapor first adsorbs on the FeS2 surface via physical adsorption followed by conversion into mercury sulfide (HgS) and mercury oxide (HgO) by the oxidation of disulfide ions (S22–) and chemisorbed oxygen (O*) species, respectively. [ABSTRACT FROM AUTHOR]

With the opening of the Chinese electricity market, as a retailer that provides energy services to consumers, the park-integrated energy system (PIES) not only serves as an effective way to earn benefits and reduce carbon emissions but also impacts the energy consumption characteristics of consumers. The PIES implements this function by adjusting the energy selling price in free energy markets. The pricing mechanism model (P-M model) is established to obtain the energy selling price in the planning and design stages. In this model, the impact of the demand response on the energy configuration and the impact of the changes in energy configuration on the energy cost price are both considered. Additionally, the optimal result ensures that both the consumers and the PIES benefit simultaneously. The reactive demand response zone, which represents a consumer trap, is found in numerical studies. The results indicate the following: (1) from the perspective of P-M model optimization, the benefit exclusive point of the PIES is the optimal solution in the short term; (2) from the perspective of the long-term benefit, the ultimate result in the relationship between the PIES and consumers is that the PIES will share its profits with consumers; in other words, benefit sharing point is the optimal solution for the long term. [ABSTRACT FROM AUTHOR]

Highlights • A home-made apparatus was developed to measure the thermal characteristics of the PCM-contained wallboard. • The "analogous step method" was proposed to determine the enthalpy of the bulk PCM in gypsum. • Three methods of obtaining H(t) curves were compared and analyzed. Abstract Phase change materials (PCM) as a smart, feasible latent heat storage material has been utilized to reduce the energy demand and improve the thermal comfort of the buildings when incorporated into the building materials. Conventionally, the thermal behavior of the PCM mixed with the solid matrix (mortar or gypsum) is different with the bulk PCM. In this study, we designed an experimental apparatus to characterize the thermal performance of PCMs when they were utilized in their implementation state. Firstly, we investigated the effective thermal conductivity (λ) and the apparent specific heat (C p) of the PCM-contained wallboard and the common gypsum wallboard, which were dependent on the temperature variation. Dynamic method was used to determine the phase change temperature, and the phase change process of the PCMs-wallboard was studied. Then, an "analogous step method" was proposed to determine the H(t) curves of the PCMs-wallboard, and the results were compared with the dynamic method. Finally, three methods of obtaining H(t) curves were compared and analyzed. From the obtained results, it can be concluded that when adopting the dynamic method appropriate heating rate (according to real application scenario) is necessary. When selecting the analogous step method, reducing the temperature interval can increase the accuracy of the H(t) even though it takes a lot of time. Anyway, both ways are more suitable for real wallboard test, comparing with the theoretical calculation method. The goal of our work is to investigate an appropriate method to evaluate the conductivities, apparent heat capacities, H(t) curves, and the phase change temperature of PCM-contained wallboards in their real application. [ABSTRACT FROM AUTHOR]

Abstract A novel n-octadecane@PMMA/TiO 2 hybrid shell PCM was prepared through a facile emulsion method, then characterized and estimated for thermal energy storage. During the synthetic process, the emulsion was enhanced by modified TiO 2 particles to improve the stability and thermal conduction. The aggregation process can be performed by an eco-friendly and efficient way, which was carried out under ultraviolet radiation for 10 min at 35 °C. The prepared microencapsulated PCMs have excellent nuclear shell structure, and the surface of the shell covered with TiO 2 particles uniformly. The TGA and DSC analysis showed that the microencapsulated PCMs have excellent thermal stability, high enthalpy and small degree of supercooling, which were suitable for thermal energy release and retrieval. The encapsulation efficiency of the microcapsules reached 67.2% when the appropriate proportion of MMA/n-octadecane was 1:1, and the melting enthalpy was 179.9 J/g. We also studied the crystallization behavior by in situ XRD method, the results showed that the crystallization behavior was different comparing with the bulk n-octadecane and hybrid shell PCMs. During the crystallization process, surface crystallization phenomenon occurred on the interface, which existed between inner surface of the microcapsules and melted n-octadecane. Subsequently, two sequential exothermic peaks were formed, which was different with bulk n-octadecane (only one exothermic peaks). The work was not only to develop a method to prepare the organic-inorganic hybrid shell Micro-PCMs, but also to study the discipline of crystallization behavior between the bulk n-octadecane and hybrid shell PCMs. Highlights • N-octadecane@PMMA/TiO 2 PCM was prepared through a facile efficient method. • The phase change behavior of composite PCMs was investigated. • The microencapsulated PCM showed excellent thermal performance. [ABSTRACT FROM AUTHOR]