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Abstract The CarbOn pilot plant is a continuous biomass carbonization system, rated for a capacity of up to 50 kg h−1 and based on open top, downdraft technology, operating in oxidative pyrolysis in the temperature range of 500–650 °C and equivalence ratio (ER) between 0.1 and 0.2. In the reported validation tests, carried out on small size chestnut woodchips, charcoal mass yield in excess of 22.4 ± 0.7 wt% (dry base) has been achieved, with a fixed carbon content higher than 85 wt% (dry base). The fixed carbon yield (FCy) was 18.2 ± 2.2 wt% (dry base), the char carbon yield (CCy) 38.3 ± 1.6 wt% (dry base) and the net energy conversion efficiency to char (ε) equal to 41.2 ± 2.2% (wet base). Volume concentration of permanent gases in the pyrolysis vapors and condensable species were also measured before incineration and critically compared against literature data. The organic condensate from oxidative pyrolysis was obtained as 4.9 wt% of the dry biomass, and around 58 wt% of its constituents have been identified; in order of decreasing abundance, the organic fraction of condensate was composed of organic acids, aromatics, furans, anhydrous sugars, phenols, methanol, PAHs, acetaldehyde, ketones. Measured and calculated performance data shows that the pilot unit can produce high quality charcoal, meeting and exceeding the product specifications set by standard EN 1860-2 for BBQ lump charcoal as well as those set forth by international voluntary standards on biochar quality for soil application. Graphical abstract Image 1 Highlights • Charcoal yield in excess of 22 wt% were obtained in autothermal carbonization. • Yield of condensable organics was 4.91 wt% of the dry biomass. • Attained energy yield in autothermal carbonization exceeding 41%. • Lower stack emission than traditional carbonization process, high T heat as co-product. • Charcoal has FC = 80.8 wt%, VM 17 wt%, Ash 2.2 wt%, BET 135.4 m2 g−1, PAH <2.5 mg kg−1. [ABSTRACT FROM AUTHOR]

The conversion of biomass to hydrocarbon transportation fuels presents unique challenges that generally focus on maintaining high mass and energy yields while removing oxygen from the biomass. Among the many processes proposed and demonstrated, processes that can achieve this efficiently and economically will have a clear advantage. Currently, there is no graphical method to analyze such conversion processes. In this work, we introduce a Funnel Plot to indicate both product quality, in terms of oxygen removal, and energy yield, the energy retained in the product oil from the original biomass. The Funnel Plot is applied to literature data for several processes and compared to an idealized chemical conversion of biomass revealing some of the current challenges associated with biofuel production. [ABSTRACT FROM AUTHOR]

Alkali metals inherent in black liquor (BL) have strong catalytic activity during gasification. A catalytic co-gasification process based on BL with pyrolysis oil (PO) has the potential to be a part of efficient and fuel-flexible biofuel production systems. The objective of the paper is to investigate how adding PO into BL alters fuel conversion under gasification conditions. First, the conversion times of single fuel droplet were observed in a flat flame burner under different conditions. Fuel conversion times of PO/BL mixtures were significantly lower than PO and comparable to BL. Initial droplet size (300–1500 μm) was the main variable affecting devolatilization, indicating control by external heat transfer. Char oxidation was affected by droplet size and the surrounding gas composition. Then, the intrinsic reactivity of char gasification was measured in an isothermal thermogravimetric analyser at T = 993–1133 K under the flow of CO 2 –N 2 mixtures. All the BL-based samples (100% BL, 20% PO/80% BL, and 30% PO/70% BL on mass basis) showed very high char conversion. Conversion rate of char gasification for PO/BL mixtures was comparable to that of pure BL although the fraction of alkali metal in char decreased because of mixing. The reactivities of BL and BL/PO chars were higher than the literature values for solid biomass and coal chars by several orders of magnitude. The combined results suggest that fuel mixtures containing up to 30% of PO on mass basis may be feasible in existing BL gasification technology. [ABSTRACT FROM AUTHOR]

The presence of contaminants considerably restricts the application of sewage sludge for the fertilisation and reclamation of soils. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment and vary widely in sewage sludge depending on the input of industrial effluents. The objective of the study was the investigation whether the pyrolysis affect (reduces or adds) the total quantity of PAHs in sewage sludge-derived biochars and whether the pyrolysis changes the PAHs spectrum in terms of relative contributions of more hazardous components. Additionally, the trace metal content was determined before and after pyrolysis as well as the ecotoxicological parameters test towards plant ( Lepidium sativum ), bacteria ( Vibrio fischeri ) and crustacean ( Daphnia magna ). Sewage sludges conversion to biochar significantly reduced the content of PAHs (from 8- to 25-fold depending on pyrolysis temperature and kind of sludge). The exception was the content of naphthalene. Naphthalene was predominant in sewage sludge-derived biochars. However the concentration of the most hazardous 5- and 6-rings PAHs in sewage sludge-derived biochars was much lower compared to sewage sludge. The pyrolysis of sewage sludges caused also a significant reduction of their toxicity towards the test organisms. Only in the case of crustacean it was observed that the extracts from some biochars, obtained at higher temperatures (600 °C and 700 °C) were more toxic to D. magna than extracts from sewage sludge. In turn, after pyrolysis an increase was noted for trace metals content (Pb, Cd, Zn, Cu, Ni and Cr). [ABSTRACT FROM AUTHOR]

Abstract: Empty fruit bunch (EFB) from oil palm is one of the potential biomass to produce biofuels like bio-oil due to its abundant supply and favorable physicochemical characteristics. Confirming the assertion, this paper presents an overview of EFB as a feedstock for bio-oil production. The fundamental characteristics of EFB in terms of proximate analysis, ultimate analysis and chemical composition, as well as the recent advances in EFB conversion processes for bio-oil production like pyrolysis and solvolysis are outlined and discussed. A comparison of properties in terms of proximate analysis, ultimate analysis and fuel properties between the bio-oil from EFB and petroleum fuel oil is included. The major challenges and future prospects towards the utilization of EFB as a useful resource for bio-oil production are also addressed. [Copyright &y& Elsevier]

The global increase in agri-food production results in a consequential societal requirement to better manage the unavoidable and copious agri-food waste (AFW) generated throughout the agri-food chain. Currently, attaining a zero AFW status is not feasible due to the inefficiencies in the agri-food chain. However, technologies to recover energy (electricity, heat, biofuel) and value-added biomaterials from AFW exist, and their effective adoption offers significant environmental and economic benefits. However, implementing efficient utilisation and valorisation of AFW at the scale needed is a non-trivial engineering challenge that must accomplish optimised energy yield (and conversion efficiencies) without environmental harm from fugitive emissions and discharge of secondary pollutants. Despite advances in standalone conversion technologies (SCTs), including thermal (incineration), biochemical (fermentation/anaerobic digestion), and thermochemical (pyrolysis, gasification and hydrothermal processes), there are still unresolved challenges (e.g., selectivity, low conversion efficiency, downstream upgrading of energy carriers), exacerbated by the accompanying production of polluting intermediates and by-products that scale with the process; potentially significant sources of GHG emissions and environmental risk if discharged untreated. Integrated conversion technologies (ICTs), that combine SCTs have been proposed as an approach that processes intermediates and by-products for further energy recovery at source. Effective implementation has the potential to enhance conversion efficiencies, energy carriers' diversification and yield. This critical appraisal of SCTs, advances in SCTs exploitation as ICTs, and developmental challenges describes the opportunities for efficient utilisation of AFW. The resultant characterisation of barriers to adopting efficient conversion technologies for AFW exploitation also aligns with growing country-level assessments of AFW bioenergy potentials and the next generation of clean energy policy priorities. • Complete agri-food waste (AFW) valorisation requires innovative approaches. • Standalone conversion technologies by-products have up to 50% residual energy. • Integrated conversion technologies enhance energy yield & conversion efficiencies. • HTC-AD integrations are most favourable for AFW; up to 91% efficiency is feasible. • Optimisation studies are critical to facilitate ICTs scale-up & commercialisation. [ABSTRACT FROM AUTHOR]

Abstract: The black cumin seed cake (BCSC) is a by-product obtained from the black cumin seeds with cold pressing. This by-product can be utilized as a biomass feedstock for conversion to bio-oil with pyrolysis process. The BCSC samples were initially pyrolyzed on a lab-scale pyrolysis system at different values in the ranges of 300–800 °C and 0.050–0.300 L min−1 to determine the effects of operation temperature and N2 flow rate on the yields on products, respectively. Then, the bio-oil in the highest yield (wB = 44.37%) which was obtained at pyrolysis final temperature (450 °C) temperature, heating rate (35 °C min−1), particle size (dp > 850 μm), and sweeping flow rate of 0.200 L min−1 was characterized by Fourier Transform infra-red (FT-IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS) and column chromatography. Consequently, it was shown that the operating temperature and N2 gas flow rate parameters were effective on the product yields. Also, the important some physico-chemical properties of the pyrolytic oil obtained in high yield were determined as the calorific value of 38.48 MJ kg−1, the empirical formula of CH1.651O0.105N0.042S0.001, the rich chemical content containing many different chemical groups, and the density of 970.25 kg m−3, and the viscosity of 63.42 mm2 s−1. Based on the determined properties of the pyrolytic oil, it was decided that the use of pyrolytic oil derived from the BCSC may possible be for the production of the alternative liquid fuels and finely chemicals after the necessary improvements. [Copyright &y& Elsevier]

Abstract: An overview of the research on biomass upgrading by torrefaction for the production of biofuels is presented. Torrefaction is a thermal conversion method of biomass in the low temperature range of 200–300°C. Biomass is pre-treated to produce a high quality solid biofuel that can be used for combustion and gasification. In this review the characteristics of torrefaction are described and a short history of torrefaction is given. Torrefaction is based on the removal of oxygen from biomass which aims to produce a fuel with increased energy density by decomposing the reactive hemicellulose fraction. Different reaction conditions (temperature, inert gas, reaction time) and biomass resources lead to various solid, liquid and gaseous products. A short overview of the different mass and energy balances is presented. Finally, the technology options and the most promising torrefaction applications and their economic potential are described. [Copyright &y& Elsevier]

Abstract: Sunn hemp (Crotolaria juncea), is a fast growing, high biomass yielding tropical legume that may be a possible southeastern bioenergy crop. When comparing this legume to a commonly grown summer legume – cowpeas (Vigna unguiculata), sunn hemp was superior in biomass yield (kgha−1) and subsequent energy yield (GJha−1). In one year of the study after 12 weeks of growth, sunn hemp had 10.7Mgha−1 of biomass with an energy content of 19.0Mgha−1. This resulted in an energy yield of 204GJha−1. The energy content was 6% greater than that of cowpeas. Eventhough sunn hemp had a greater amount of ash, plant mineral concentrations were lower in some cases of minerals (K, Ca, Mg, S) known to reduce thermochemical conversion process efficiency. Pyrolytic degradation of both legumes revealed that sunn hemp began to degrade at higher temperatures as well as release greater amounts of volatile matter at a faster rate. [Copyright &y& Elsevier]