Towards Biochar and Hydrochar Engineering—Influence of Process Conditions on Surface Physical and Chemical Properties, Thermal Stability, Nutrient Availability, Toxicity and Wettability

Dieguez-Alonso, Alba; Funke, Axel; Anca-Couce, Andrés; Rombolà, Alessandro G.; Ojeda, G.; Bachmann, Jörg; Behrendt, Frank

doi:10.3390/en11030496

Cited by 98 publications

(60 citation statements)

References 66 publications

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“…Hydrothermal carbonization (HTC) is a thermochemical process converting biomass into lignite‐like products (hydrochar), which takes place in water under subcritical conditions . The combination of temperatures between 180 °C and 250 °C and pressures between 20–80 bars forms a process that replicates the natural process of coal generation.…”

Section: Potential Developments In Closing Of Materials Cyclesmentioning

confidence: 99%

“…Hydrothermal carbonization (HTC) is a thermochemical process converting biomass into lignite-like products (hydrochar), which takes place in water under subcritical conditions. 75,[167][168][169][170] The combination of temperatures between 180 °C and 250 °C 171 and pressures between 20-80 bars 161 forms a process that replicates the natural process of coal generation. During the process, both biomass and water are heated in a pressurized reactor for several hours, which reduces the hydrogen and oxygen contents of the feed and increases its carbon content and energy density.…”

Section: Process Description Of Hydrothermal Carbonization (First Step)mentioning

confidence: 99%

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The replacement of maize (Zea mays L.) by cup plant (Silphium perfoliatum L.) as biogas substrate and its implications for the energy and material flows of a large biogas plant

Cossel

Amarysti

Wilhelm

et al. 2020

Biofuels Bioprod Bioref

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Excessive cultivation of maize (Zea mays L.) as a biogas substrate has fired debate about potential land‐use change effects of bioenergy cropping systems. Cup plant ( Silphium perfoliatum L.) is a perennial biogas crop that provides more environmental services than maize. This study investigated (i) how to replace maize with cup plant as a biogas substrate in a large‐scale biogas plant located in southwest Germany, and (ii) how to optimize the energy and material cycles of such a biogas plant given the new feedstock. The biogas plant produces 1000 m3 biogas per hour with plans for it to be combined with a large dairy farm (1000 dairy units). It was found that the substitution of maize with cup plant as a biogas substrate results in a methane yield reduction of 10% to 20% due to lower biomass yields. However, there exists a strong potential to increase both biomass yields and biogas substrate quality of cup plant by optimizing establishment procedures and better genotypes. Furthermore, cup plant provides food and shelter for open land animals, including birds and insects, and could hence be a suitable alternative to maize for large biogas plants, being more environmentally beneficial. Extracting proteins from cup‐plant biomass could also help replace soy with locally produced protein for feeding cattle. Hydrothermal carbonization is a promising tool for closing nutrient cycles and for extracting phosphate from digestate, but more research is needed before it can be put into practice. © 2020 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd.

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Section: Potential Developments In Closing Of Materials Cyclesmentioning

confidence: 99%

Section: Process Description Of Hydrothermal Carbonization (First Step)mentioning

confidence: 99%

The replacement of maize (Zea mays L.) by cup plant (Silphium perfoliatum L.) as biogas substrate and its implications for the energy and material flows of a large biogas plant

Cossel

Amarysti

Wilhelm

et al. 2020

Biofuels Bioprod Bioref

View full text Add to dashboard Cite

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“…Moreover, grindability of the processed biomass can be significantly enhanced [39]. Therefore, HTC can be considered as a prospective valorization process for low quality biomass, especially when wet biomass is concerned as a potential feedstock for biorefineries [40][41][42][43][44][45] or as a component of high quality solid biofertilizers [44,46,47].Performance of the HTC process is typically determined directly, by means of mass yield, energy yield and energy densification ratio [24,27,[41][42][43]48]. Recently some studies attempted using an indirect method for this purpose [8], originally developed for production of biochar [49].…”

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confidence: 99%

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confidence: 99%

HTC of Wet Residues of the Brewing Process: Comprehensive Characterization of Produced Beer, Spent Grain and Valorized Residues

et al. 2020

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Steady consumption of beer results in a steady output of residues, i.e., brewer's spent grain (BSG). Its valorization, using hydrothermal carbonization (HTC) seems sensible. However, a significant knowledge gap regarding the variability of this residue and its influence on the valorization process and its potential use in biorefineries exists. This study attempted to fill this gap by characterization of BSG in conjunction with the main product (beer), taking into accounts details of the brewing process. Moreover, different methods to assess the performance of HTC were investigated. Overall, the differences in terms of the fuel properties of both types of spent grain were much less stark, in comparison to the differences between the respective beers. The use of HTC as a pretreatment of BSG for subsequent use as a biorefinery feedstock can be considered beneficial. HTC was helpful in uniformization and improvement of the fuel properties. A significant decrease in the oxygen content and O/C ratio and improved grindability was achieved. The Weber method proved to be feasible for HTC productivity assessment for commercial installations, giving satisfactory results for most of the cases, contrary to traditional ash tracer method, which resulted in significant overestimations of the mass yield.However, for craft breweries located in big cities, disposal becomes more problematic [3]. There are also attempts to enrich food products with spent grains. Thus far, there have been trials with sausages [4] and bread [5]. However, consumers reported that such products represent a fiber aftertaste [6]. However, this is limited only to the relatively close vicinity of a brewery, due to relatively high moisture content, that could range between 70% up to 78% 70% [7][8][9]. Biological activity of these residues makes long term storage difficult. The literature reports ongoing work on various new ways of using BSG, including extraction of polyphenols [10,11], other anti-oxidants [12,13], functional cardioprotective lipids for pharmaceutic use [14], proteins [15], fodder for edible insects [16], material for disposable trays [17], natural rubber modifier [18], as well as feedstock for production of pigments [19] and biochar, for subsequent use as soil amendment [20] or sustainable material for electrodes [21].The potential use of this residue as a fuel has been suggested by several authors so far [7][8][9]22,23]. The relatively high initial moisture content of spent grain makes hydrothermal valorization techniques the most sensible choice [8,9]. Hydrothermal carbonization (HTC), also known as wet torrefaction, is a valorization process suitable for a range of low-quality solid biomass, especially with high initial moisture content [24,25]. Process temperature, reported in the literature, usually ranges between 180 • C and 260 • C [25][26][27][28][29][30]. As the process takes place in subcritical water, pressure has to be higher than saturation pressure of water for specific temperature [25][26][27][28][29][30]. In these conditions wa...

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“…In the search of new materials with enhanced properties, hydrothermal carbonization (HTC) methods affording non‐porous and spherically‐shaped hydrochars enriched with sulfonic, amino, aminopropyltriethoxysilane or ethylenediamino groups have been reported involving renewable biomass as carbon precursors . Up to now, the presence of multiple functional groups on the surface of the hydrochars has limited their chemoselective functionalization . A glutaraldehyde cross‐linked polyethylene imine strategy has successfully been applied for the derivatization of hydrochars, but more efforts are required for their selective functionalization.…”

Section: Introductionmentioning

confidence: 99%

Tetraalkylammonium Functionalized Hydrochars as Efficient Supports for Palladium Nanocatalysts

et al. 2020

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With the aim of preparing bio-sourced supports with enhanced properties in catalysis, we devised an original strategy allowing the immobilization of metal nanoparticles. Thus, size-controlled hydrochars with a high degree of hydroxyl functionalities, from both neat sucrose or modified with acrylic acid (10 wt.%), were derivatized with ether linkers containing ammonium groups. These non-porous carbon-based materials were used as suitable supports for the immobilization of palladium nanoparticles. The catalytic materials were synthesized by reduction of Pd(OAc) 2 to Pd(0) under H 2 atmosphere in the presence of the corresponding hydrochar, and fully characterized by standard methods. Among the different hydrochar-supported palladium materials, those functionalized with tetraalkylammonium groups afforded heterogeneous catalysts, exhibiting high activity in hydrogenations of different types of substrates (alkynes, alkenes, and carbonyl and nitro derivatives). The most efficient catalyst was recycled up to ten runs without loss of catalytic behavior, in agreement with the unchanged composite materials after catalysis (Transmission Electron Microscopy (TEM) analyses) and the lack of metal leaching in the extracted organic products (no palladium detected by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES)); these systems exhibited enhanced recyclability properties as compared to commercial Pd/C catalyst.

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Towards Biochar and Hydrochar Engineering—Influence of Process Conditions on Surface Physical and Chemical Properties, Thermal Stability, Nutrient Availability, Toxicity and Wettability

Cited by 98 publications

References 66 publications

The replacement of maize (Zea mays L.) by cup plant (Silphium perfoliatum L.) as biogas substrate and its implications for the energy and material flows of a large biogas plant

The replacement of maize (Zea mays L.) by cup plant (Silphium perfoliatum L.) as biogas substrate and its implications for the energy and material flows of a large biogas plant

HTC of Wet Residues of the Brewing Process: Comprehensive Characterization of Produced Beer, Spent Grain and Valorized Residues

Tetraalkylammonium Functionalized Hydrochars as Efficient Supports for Palladium Nanocatalysts

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