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Thermogravimetry (TG) was employed to understand the interactions between ionic liquids (ILs) and biomass components. The thermal decomposition profiles of several biomass samples with IL pretreatment at different temperatures were studied by TG. Samples of Avicel (PH101), xylan from beechwood and alkaline lignin as well as switchgrass and corn stover were pretreated using 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) at temperatures of 50-130°C for 6h. Analysis of TG data provided insight into the mode of degradation of xylan and lignin in [C4mim][OAc]. Pretreated Avicel samples exhibited higher decomposition temperatures due to transformation from cellulose I into cellulose II, while samples of switchgrass and corn stover showed an improved thermal stability as a result of removal of minerals by [C4mim][OAc]. More intensive pretreatment produced decreased thermal resistance due to degradation of biomass components and decrystallization., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

X-ray diffraction (XRD) was used to understand the interactions of cellulose in lignocellulosic biomass with ionic liquids (ILs). The experiment was designed in such a way that the process of swelling and solubilization of crystalline cellulose in plant cell walls was followed by XRD. Three different feedstocks, switchgrass, corn stover and rice husk, were pretreated using 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) at temperatures of 50-130°C for 6h. At a 5 wt.% biomass loading, increasing pretreatment temperature led to a drop in biomass crystallinity index (CrI), which was due to swelling of crystalline cellulose. After most of the crystalline cellulose was swollen with IL molecules, a low-order structure was found in the pretreated samples. Upon further increasing temperature, cellulose II structure started to form in the pretreated biomass samples as a result of solubilization of cellulose in [C4mim][OAc] and subsequent regeneration., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

To reduce indoor air pollution, the government of Ghana in 2019 formulated the renewable energy master plan to help disseminate biomass pellets and stoves to 2,000,000 households by 2030. But pellets have neither been included in Ghana's energy mix nor have their surmised climate and health benefits been empirically assessed. This laboratory study tested emissions by burning wood, charcoal and pellets in improved cookstoves. It further modelled their associated indoor air pollution reduction, personal exposure, health benefits and climate impact for comparison. The emission factors based on useful energy delivered of CO, CO 2 and PM 2.5 were 3.506 ± 0.704, 306.6 ± 43.35, and 0.229 ± 0.039 g/MJ delivered , respectively, for wood rocket 1 stove; 2.115 ± 0.695, 272.8 ± 16.70, and 0.256 ± 0.166 g/MJ delivered for wood rocket 2 stove; 4.820 ± 1.098, 205.3 ± 60.49, and 0.051 ± 0.044 g/MJ delivered for charcoal 1 stove; 4.474 ± 1.525, 221.8 ± 65.71, 0.043 ± 0.040 g/MJ delivered for charcoal 2 stove; and 0.511 ± 0.325, 338.1 ± 45.41, and 0.041 ± 0.023 g/MJ delivered for pellet stove. The forced air supplied by the gasifier stove reduced pollutant emissions from pellet combustion. The 100-year global warming contribution of the pellet stove was lower than that of charcoal stoves, and was influenced by upstream emissions of fuel processing. The WHO (World Health Organization) models showed that a complete transition from wood to pellets in one million households could significantly improve health with most benefits for children below five years. However, the reported benefits can only be achieved if pellets are added to Ghana's energy mix. The government of Ghana can ensure a sustained adoption of pellets by fostering market enablers for supply and demand of pellets and gasifier stoves, and mitigating the factors that impact pellet production and use. Field evaluation of the economic, health and climate co-benefits of using pellets in Ghana is recommended for future study. • Pellets burning had significantly lower CO and PM 2.5 emissions than charcoal and wood. • Transitioning from wood to pellets in one million households could avert 24,994 DALYs and 592 deaths every year. • Switching from charcoal to pellets showed no significant health benefits. • The 100-year global warming contribution of pellets was ~ 5% lower than those of charcoal stoves. [ABSTRACT FROM AUTHOR]

Agricultural residues, such as lignocellulosic materials (LM), are the most attractive renewable bioenergy sources and are abundantly found in nature. Anaerobic digestion has been extensively studied for the effective utilization of LM for biogas production. Experimental investigation of physiochemical changes that occur during pretreatment is needed for developing mechanistic and effective models that can be employed for the rational design of pretreatment processes. Various-cutting edge pretreatment technologies (physical, chemical and biological) are being tested on the pilot scale. These different pretreatment methods are widely described in this paper, among them, microaerobic pretreatment (MP) has gained attention as a potential pretreatment method for the degradation of LM, which just requires a limited amount of oxygen (or air) supplied directly during the pretreatment step. MP involves microbial communities under mild conditions (temperature and pressure), uses fewer enzymes and less energy for methane production, and is probably the most promising and environmentally friendly technique in the long run. Moreover, it is technically and economically feasible to use microorganisms instead of expensive chemicals, biological enzymes or mechanical equipment. The information provided in this paper, will endow readers with the background knowledge necessary for finding a promising solution to methane production. [ABSTRACT FROM AUTHOR]

Microwave based technology is an alternative heating method and has already been successfully used in biomass pyrolysis for biochar and biofuel production thanks to its fast, volumetric, selective and efficient heating. Previous review mainly focused on production and analysis of bio-oil and gas instead of biochar. The current paper provides a review of microwave-assisted pyrolysis (MWP) of biomass and its biochar characteristics, including product distribution and biochar yield, biochar properties, microwave absorbers (MWAs) and catalysts commonly used in MWP, as well as comparison of biochar derived from MWP and conventional pyrolysis (CP). MWAs not only absorb microwave energy, they also act as catalysts to interact with gas, vapor and solids in the reactor, adjusting the product distribution and quality of products. It was reported for MWP that the highest biochar yield was >60 wt% and the maximum BET surface area was about 450–800 m 2 /g. Technology status and economics of MWP of biomass in China were briefly introduced. The Optimization of yield and quality of biochar strongly depends on feedstock properties, reactor types, operating parameters, MWAs and catalysts added to the system. [ABSTRACT FROM AUTHOR]

Activated carbon has been widely used as adsorbents, catalyst support and energy storage materials. Microwave heating is a promising technique for thermochemical treatment and activation of activated carbons due to its fast, selective, uniform and volumetric heating. Previous reviews mainly focused on specific feedstocks (e.g. agricultural biomass or oil palm wastes) or ignored important parameters for microwave activation (e.g. mass of activated carbon precursor). Characteristics of activated carbons prepared from conventional and microwave treatment were not compared and economics of microwave activation were not described in previous studies. This paper presentst a state of the art review of activation under microwave irradiation for various biomass sources (e.g. agricultural wastes, woody biomass and sewage sludge). Characteristics of microwave heating, main activation parameters, research progress and technology status of activated carbon preparation and regeneration under microwave irradiation are investigated with key challenges and economics being addressed. Characteristics of activated carbons made from microwave irradiation and conventional activation are compared and the advantages of microwave-assisted preparation are highlighted. It shows that the BET (Brunauer–Emmett–Teller) surface area, iodine number, methylene blue adsorption capacity and the yield of activated carbons under microwave irradiation are up to 2500–3000 m 2 /g, 1800–2200 mg/g, 500–700 mg/g and 13–96 wt%, respectively, competitive with conventional methods on the quality of activated carbons and process economics. Potential applications and future perspectives are described with pertinent information on activated carbon preparation under microwave irradiation. [ABSTRACT FROM AUTHOR]

Searching and exploring for new biomass sources is essential for biofuels production. Furfural residue pellets (FRPs), sawdust pellets (SPs), corn stalk pellets (CSPs) and sewage sludge pellets (SSPs) were produced using single pellets press, their quality was analysed and compared. Proximate and ultimate parameters varied for all pellets depending on their chemical composition. FRPs had the highest relaxed density (1.431 g/cm3) than SPs and CSPs at 130 °C and strength (∼6 MPa) than CSPs and SSPs at 200 °C. Among all pellets, SPs achie v ed higher strength of 10.38 MPa. Porosity (3.42 v%) and moisture absorption (7.68%) of FRPs were found lower than SPs, CSPs, and SSPs. Compression energy for FRPs (24.15 J/g) and SSPs (18.64 J/g) was found to be lower than SPs and CSPs, making more economic sense and indicating the potential of biomass wastes for co-pelletization with other biomass sources. Higher heating value of FRPs (22.45 MJ/kg), SPs and CSPs (∼20 MJ/kg) were found satisfactory and met the set standards. FRPs had higher volumetric energy density (32.06 kJ/cm3) compared to other pellets. There were no or very less heavy metals contents in FRPs, SPs and CSPs than SSPs. From overall ranking, FRPs were found higher in rank, followed by SPs. • Physical, chemical, mechanical and thermal characteristics of pellets were studied. • Among all, FRPs had lower porosity, moisture absorption and higher strength at 130 °C. • SPs achieved higher relaxed density and strength and lower porosity and E c at 200 °C. • HHV of FRPs (22.45 MJ/kg), SPs and CSPs (∼ 20 MJ/kg) met the Enplus standards. • From overall ranking, FRPs were found higher in rank, followed by SPs. [ABSTRACT FROM AUTHOR]

Greece and China are two agricultural countries in which a significant percentage of their biomass consists of agricultural and livestock wastes. In Greece, the management practice that is still applied is burning the majority of the agricultural residues in the field, while in China large amount of untreated agricultural waste causes serious adverse effects on the rural living environment. Residual biomass could arise from the agricultural sector in the form of crop residues and of animal wastes. A comprehensive literature review was performed for both countries on primary agricultural and livestock wastes that includes: (a) crop residues that are left in the fields, (b) animal manures and (c) secondary agricultural wastes consisted of liquid and solid wastes from agricultural products processing plants. The average annual quantity of agricultural residues, animal manure and agro-industrial residues in Greece and China (a small and a large country, respectively) is 10 Mt/y and 860 Mt/y, 26 Mt/y and 216.5 Mt/y, 13.2 Mt/y and 213.7 Mt/y, for each corresponding category. According to the amount of the above residues generated per country, the theoretical estimated energy can reach up to 77 TWh and 5500 TWh for Greece and China, respectively, which suggests that both countries can cover a significant part of their energy needs (approximately 135% and 99%, respectively) only from their agricultural and livestock wastes. Τhese observations constitute strong recommendations mainly addressed to policy makers to substantially strengthen the efforts of research, technological and economic optimization of the applications of energy use of agricultural residual biomass for the benefit of the environment and humanity. • There is a lack in literature regarding the detailed recording of the total quantities of residual agricultural biomass. • A review was performed for Greece and China on (a) crop residues, (b) animal manures and (c) agro-industrial wastes. • It was found that Greece and China can cover their energy needs only from their agricultural and livestock wastes. • The results can provide a sound basis to meet energy needs not only in the countries concerned but also worldwide. [ABSTRACT FROM AUTHOR]