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Biomass solid fuel (BSF) has emerged as a promising renewable energy source, but its morphological and microstructural properties are crucial in determining their physical, mechanical, and chemical characteristics. This paper provides an overview of recent research on BSF. The focus is on biomass sources, BSF processing methods, and morphological and microstructural properties, with a special emphasis on energy-related studies. Specific inclusion and exclusion criteria were established for the study to ensure relevance. The inclusion criteria encompassed studies about BSFs and studies investigating the influence of biomass sources and processing methods on the morphological and microstructural properties of solid fuels within the past five years. Various technologies for converting biomass into usable energy were discussed, including gasification, torrefaction, carbonization, hydrothermal carbonization (HTC), and pyrolysis. Each has advantages and disadvantages in energy performance, techno-economics, and climate impact. Gasification is efficient but requires high investment. Pyrolysis produces bio-oil, char, and gases based on feedstock availability. Carbonization generates low-cost biochar for solid fuels and carbon sequestration applications. Torrefaction increases energy density for co-firing with coal. HTC processes wet biomass efficiently with lower energy input. Thermal treatment affects BSF durability and strength, often leading to less durability due to voids and gaps between particles. Hydrothermal carbonization alters surface morphology, creating cavities, pores, and distinctive shapes. Slow pyrolysis generates biochar with better morphological properties, while fast pyrolysis yields biochar with lower porosity and surface area. Wood constitutes 67% of the biomass sources utilized for bioenergy generation, followed by wood residues (5%), agro-residues (4%), municipal solid wastes (3%), energy crops (3%), livestock wastes (3%), and forest residues (1%). Each source has advantages and drawbacks, such as availability, cost, environmental impact, and suitability for specific regions and energy requirements. This review is valuable for energy professionals, researchers, and policymakers interested in biomass solid fuel. [ABSTRACT FROM AUTHOR]

Coal is the most widely used primary fuel for energy generation but it emits toxic gasses after combustion. Whereas, biomass is a renewable energy source and it is used for environment friendly energy production. Biomass does not add carbon dioxide to the atmosphere because it absorbs the same amount of carbon in growing as it releases when consumed as fuel. Generally, biomass used for co-firing with coal includes wood and woody wastes, municipal solid waste, animal wastes, agricultural crops and their waste by-products, waste from food processing, aquatic plants and algae. The inherent moisture content in biomass decreases its heating value and it needs to be dried before using it for co-firing. The drying of biomass could be performed in various types of dryers and all of them have their own merits and demerits. This paper provides a detail review on the need of drying of biomass before co-firing, different technologies used for biomass drying, biomass co-firing to the existing coal fired power plants and the environmental benefits of biomass co-firing. [ABSTRACT FROM AUTHOR]

Abstract: Biomass gasification in fluidized bed system by using air–steam mixture as the gasifying agent is a promising way of utilizing biomass because it produces a gaseous fuel having relatively higher calorific value as well as higher hydrogen content with minimum or no heat addition to the gasifier. In the present work, a three dimensional numerical simulation of a bubbling fluidized bed biomass gasifier has been carried out. The numerical simulation is based on the Eulerian–Lagrangian approach where the fluid phase is solved by using a continuum approach and the solid is modeled by using Lagrangian computational particle model. The chemical reactions are coupled with the complex hydrodynamic calculation of gas–solid fluidized bed. The simulations are performed by varying the gasification temperature, equivalence ratio and steam-to-biomass ratio. Detail analyses of flow pattern, pressure distribution, and gas composition distribution have been presented. The complex three dimensional flow structures are revealed by plotting the results in different planes. The results provide a detail insight into the gasifier׳s behavior including fluidization, thermal and chemical characteristics. Simulated outlet gas compositions are compared with our own experimental data and a very good resemblance is observed. [Copyright &y& Elsevier]

Abstract: In the present work, the generation of hydrogen rich synthetic gas from fluidized bed steam gasification of rice husk has been studied. An equilibrium model based on equilibrium constant and material balance has been developed to predict the gas compositions. The equilibrium gas compositions are compared with the experimental data of the present group as well as of available literature. The energy and exergy analysis of the process have been carried out by varying steam to biomass ratio (ψ) within the range between 0.1–1.5 and gasification temperature from 600 °C to 900 °C. It is observed that both the energy and exergy efficiencies are maximum at the CBP (carbon boundary point) though the hydrogen production increases beyond the CBP. The HHV (higher heating value) and the external energy input both continuously increase with ψ. However, the hydrogen production initially increases with increase in temperature up to 800 °C and then becomes nearly asymptotic. The HHV decreases rapidly with increase in temperature and energy input increases. Therefore, gasification in lower temperature region is observed to be economical in terms of a trade off between external energy input and HHV of the product gas. [Copyright &y& Elsevier]

Abstract: This paper presents the investigation of the performance from different biomasses in a fluidized bed gasifier where steam has been used as gasifying as well as fluidizing agent. An experimental setup is fabricated to study the gasification performance of rice husk, which is of special relevance to rice-producing countries like China and India. An equilibrium modeling approach is deployed to predict the gas composition which has been compared with the experimental results. Calibration of the model with appropriate modeling coefficients was necessary to achieve close resemblance with the experimental values. Further, the model is used to predict the gas compositions from other biomass and benchmarked with the performance of coal. In this study, the gasification temperature is varied from 650°C to 800°C, whereas the steam-to-biomass ratio (S/B) is varied from 0.75 to 2.00. As the gasification temperature increases, the production of H2 and CO increases but the generation of CH4 and CO2 reduces. The steam-to-biomass ratio was again found to influence the production rates. With increasing steam input, H2, CO2 and CH4 were found to increase while CO reduces. [ABSTRACT FROM AUTHOR]