An overview of commercially used brominated flame retardants, their applications, their use patterns in different countries/regions and possible modes of release.

Lignocellulosic biomass pyrolysis mechanism: A state-of-the-art review

Modeling chemical and physical processes of wood and biomass pyrolysis

Torrefaction is a mild pyrolysis, which has been explored for the pretreatment of biomass to increase the heating value and hydrophobicity. Due to its potential applications for making torrefied pellets, which can be used as a high quality feedstock in gasification for high quality syngas production and as a substitute for coal in thermal power plants and metallurgical processes, torrefaction and densification have attracted great interest in recent years from both academia and bioenergy industry. This paper provides a comprehensive review of research progresses in this area, drawing on major contributions from two major research groups of the authors on torrefaction and densification at Canada and Taiwan as well as literatures. It is revealed that torrefaction of various biomass species and their major components, lignin, cellulose and hemicelluloses have been extensively studied in thermogravimetric apparatus (TGA) under both inert (N 2 ) and oxidative (O 2 , H 2 O) environments to elucidate the weight loss as a function of temperature, particle size and time. It was found that the higher heating value and saturated water uptake of torrefied biomass were a strong function of weight loss, which represents the degree of torrefaction. When torrefied sawdust is compressed into torrefied pellets, more mechanical energy is consumed and higher die temperature is required to make torrefied pellets of similar density and hardness as regular pellets. Simple economics analyses based on laboratory scale experimental data showed that because of the potential savings from pellets transport, handling and storage logistics, the overall cost for torrefied pellets can be lower than regular pellets in European market for both European and Canadian pellets. The gasification could be improved in terms of both energy efficiency and syngas quality because of the removal of oxygenated volatile compounds from torrefied biomass.

A state-of-the-art review of biomass torrefaction, densification and applications

A review was conducted on the use of thermochemical biomass gasification for producing biofuels, biopower and chemicals. The upstream processes for gasification are similar to other biomass processing methods. However, challenges remain in the gasification and downstream processing for viable commercial applications. The challenges with gasification are to understand the effects of operating conditions on gasification reactions for reliably predicting and optimizing the product compositions, and for obtaining maximal efficiencies. Product gases can be converted to biofuels and chemicals such as Fischer-Tropsch fuels, green gasoline, hydrogen, dimethyl ether, ethanol, methanol, and higher alcohols. Processes and challenges for these conversions are also summarized.

https://www.mdpi.com/1996-1073/2/3/556/pdf

Thermochemical biomass gasification—a review of the current status of the technology

Biomass fuels represent a renewable energy source, they are CO2 neutral fuels, and their use reduces the consumption of fossil fuels and limits the emissions of SOx, NOx, and heavy metals. They are...

Devolatilization of Biomass Fuels and Biomass Components Studied by TG/FTIR Technique

Heat of wood pyrolysis

The thermal stability and decomposition products of hexabromocyclododecane (HBCD), a widely used aliphatic brominated flame retardant, were investigated. HBCD thermal degradation was carried out in nitrogen and in air at moderate heating rates (10 °C/min) using thermogravimetric analyzers and a laboratory-scale fixed-bed reactor. The identification of decomposition products was based mainly on FTIR and gas-chromatographic/mass-spectrometric techniques. Quantitative data on hydrogen bromide formation and on the bromine distribution among the different product fractions were obtained. For the experimental conditions used in this study, about 75 wt % of the bromine is released as HBr, and 25 wt % is involved in the formation of high-molecular-weight bromo-organic compounds. The main pathways of HBCD thermal degradation were assessed, and a global mechanism for HBCD decomposition was proposed.

Thermal stability and decomposition products of hexabromocyclododecane

Production of electronic boards containing brominated flame retardants is constantly increasing, posing important problems with disposal of products containing these materials. The present study investigated the thermal degradation behavior of electronic boards manufactured using tetrabromobisphenol A and diglycidyl ether of bisphenol A epoxy resins. Qualitative and quantitative information was obtained on the products formed in the thermal degradation process, and the bromine distribution in the different product fractions was determined. The more important decomposition products included hydrogen bromide, phenol, polybrominated phenols, and polybrominated bisphenol A species. The formation of considerable amounts of hydrogen bromide and high-molecular-weight organobrominated compounds, as well as the potential formation of limited quantities of polybrominated dibenzo-p-dioxins and dibenzofurans, is an important element of concern in the safety and environmental assessment of the thermal degradation proc...

Federica Barontini

Papers

Devolatilization of Biomass Fuels and Biomass Components Studied by TG/FTIR Technique

Heat of wood pyrolysis

Thermal stability and decomposition products of hexabromocyclododecane

Thermal Degradation and Decomposition Products of Electronic Boards Containing BFRs

Formation of hydrogen bromide and organobrominated compounds in the thermal degradation of electronic boards