Carbon monoxide inhibition on acidogenic glucose fermentation and aceticlastic methanogenesis.

Syngas and CO-rich off-gases are key chemical platforms to produce biofuels and bioproducts. From the perspective of optimizing and up-scaling CO co-digestion with organic waste streams, this study aims at assessing and quantifying the inhibitory effects of CO on acidogenic glucose fermentation and aceticlastic methanogenesis. Mesophilic cultures were fed in two sets of batch assays, respectively, with glucose and acetate while being exposed to dissolved CO in equilibrium with partial pressures in the range of 0.

Fast screening of catalyst performances in hydrothermal processes for biofuel production using differential scanning calorimetry.

Catalysts are usually employed in hydrothermal processes for different purposes, such as enhancing quality and yield of produced biofuels. However, assessing catalyst performances can be time consuming and expensive. For this reason, in this work, a technique based on high pressure differential scanning calorimetry was applied to study heterogeneous catalyst behavior under hydrothermal conditions at the micro-scale.

Uncovering the transition between hydrothermal carbonization and liquefaction via secondary char extraction: A case study using food waste.

Despite the ability to perform both processes in the same reactor, hydrothermal carbonization (HTC) and hydrothermal liquefaction (HTL) are considered two distinct processes differentiated by their reaction temperatures. As temperatures increase from the less severe HTC range into the HTL regime, the product distribution progressively favors an organic bio-oil phase relative to solid hydrochar. Solvents are commonly used to extract bio-oil from the solid residues produced during HTL, and to separate the amorphous secondary char from the coal-like primary char of HTC hydrochars.

Combustion kinetics of hydrochar from cow-manure digestate via thermogravimetric analysis and peak deconvolution.

Hydrothermal carbonization (HTC) can convert wet biomass into hydrochar (HC), a solid carbonaceous material exploitable as fuel. In this study, HTC was applied to anaerobic digestate from cow manure. HCs obtained at three HTC temperatures (180, 220, 250 °C) were characterized in detail and their combustion behavior was investigated by thermogravimetric analysis (TGA) coupled with peak deconvolution.

Effect of solvent and feedstock selection on primary and secondary chars produced via hydrothermal carbonization of food wastes.

Hydrothermal carbonization is a thermochemical process that converts wet waste biomass into hydrochar, a renewable solid fuel that comprises a coal-like primary phase and an oily secondary phase. The varying oxidation rates of these phases may result in an inefficient energy recovery when combusting the hydrochar, as secondary char is more reactive. Brewer's spent grain, dairy cheese whey and food waste were hydrothermally carbonized at 250 °C.

Subcritical water hydrolysis coupled with hydrothermal carbonization for apple pomace integrated cascade valorization.

This study evaluates an integrated biorefinery approach based on the waste hierarchy for the valorization of biodegradable waste, focusing on apple processing residues. Firstly, subcritical water hydrolysis was investigated at different experimental conditions (temperature 80 to 120 °C, dilution factor 10 to 30, residence time 10 to 30 min, initial pressure 10 to 30 bar) with the coincident aim of dissolving fermentable sugars and assess the effects of such treatment on the downstream solids. Secondly, spent solids were further processed by hydrothermal carbonization in the same reactor at fixed conditions (i.

Evaluating the Aqueous Phase From Hydrothermal Carbonization of Cow Manure Digestate as Possible Fertilizer Solution for Plant Growth.

Improving the agronomic use of recycled nutrients derived from organic waste is one of the priorities within the measures adopted by the European community to reduce environmental issues but remains an unexplored area of research. This study focused on investigating the possibility of using innovative fertilizer solutions in hydroponic systems for the growth of agricultural plants. To this purpose, a liquid fraction [aqueous hydrothermal carbonization (HTC) liquid (AHL)] derived from HTC of cow manure digestate was chemically characterized (pH, electrical conductivity, mineral elements, and organic compounds such as phytotoxins), diluted with distilled water (1:30, 1:60, and 1:90, v/v) to reduce its potential phytotoxicity, and used to grow hydroponic maize ( L.

Phytotoxicity of hydrochars obtained by hydrothermal carbonization of manure-based digestate.

The management of digestate, the main by-product of the anaerobic digestion (AD) process, is one of the most serious environmental issues. Although digestate is used on arable land as a fertilizer, it can have a negative impact on the environment due to nitrate leaching into the groundwater and ammonia volatilization into the atmosphere, with high economic and environmental disposal costs. Therefore, hydrothermal carbonization (HTC), a thermochemical biomass conversion process, could represent a sustainable and efficient alternative for digestate management.

Effects of woody biochar on dry thermophilic anaerobic digestion of organic fraction of municipal solid waste.

This study presents the results of semi-pilot scale anaerobic digestion tests conducted under dry thermophilic conditions with the addition of biochar (6% on fresh mass basis of inoculum), derived from an industrial gasification plant, for determining biogas and biomethane production from organic fraction of municipal solid waste. By using two types of inocula (from a full-scale dry anaerobic digestion plant and from lab-scale biomethanation tests), the obtained experimental results did not show significant increase in methane yield related to the presence of biochar (330.40 NL CH kgVS using plant inoculum; 335.

Techno-economic assessment of turning gasification-based waste char into energy: A case study in South-Tyrol.

In the South-Tyrol region (Italy), 46 gasifiers are currently operating and €200,000 are annually paid to dispose of as a waste 1300 tons of char. Therefore, there is a considerable interest in finding alternatives for the valorization of this solid by-product. The aim of this work is to assess the potential of char as energy source and to compare two scenarios.

Mesoporous Acidic Catalysts Synthesis from Dual-Stage and Rising Co-Current Gasification Char: Application for FAME Production from Waste Cooking Oil.

The main purpose of this work is to investigate the application options of the char produced from gasification plants. Two promising mesoporous acidic catalysts were synthesized using char as a support material. Two char samples were collected from either a dual-stage or a rising co-current biomass gasification plant.

The "COFFEE BIN" concept: centralized collection and torrefaction of spent coffee grounds.

Spent coffee grounds are the moist solid residues of coffee brewing and in most cases, the disposal is done without any intermediate valorization actions for materials and energy recovery. State-of-the-art applications include extraction of the liquids and application of high-temperature pyrolysis. Both strategies have significant potential but have also some disadvantages (extensive pre-treatment, high costs) when applied on a large scale.

Valorization of Char From Biomass Gasification as Catalyst Support in Dry Reforming of Methane.

This study responds to the need of finding innovative routes for valorizing char derived from biomass gasification. Char is currently treated as a waste representing an energetic and economic loss for plant owners. However, it displays many similarities to activated carbon (AC) and could replace it in several applications.

The case of Frictional Torrefaction and the effect of reflux condensation on the operation of the Rotary Compression Unit.

This work introduces the process of Frictional Torrefaction and comes as a continuation to the previous work done on Frictional Pyrolysis, which is a novel method of pyrolysis that does not utilize heat but only friction and pressure. Both processes (i.e.

Modeling the emissions of a dual fuel engine coupled with a biomass gasifier-supplementing the Wiebe function.

There is a growing market demand for small-scale biomass gasifiers that is driven by the economic incentives and the legislative framework. Small-scale gasifiers produce a gaseous fuel, commonly referred to as producer gas, with relatively low heating value. Thus, the most common energy conversion systems that are coupled with small-scale gasifiers are internal combustion engines.

Thermodynamic modeling of small scale biomass gasifiers: Development and assessment of the ''Multi-Box'' approach.

Modeling can be a powerful tool for designing and optimizing gasification systems. Modeling applications for small scale/fixed bed biomass gasifiers have been interesting due to their increased commercial practices. Fixed bed gasifiers are characterized by a wide range of operational conditions and are multi-zoned processes.

Agro-industrial waste to solid biofuel through hydrothermal carbonization.

In this paper, the use of grape marc for energy purposes was investigated. Grape marc is a residual lignocellulosic by-product from the winery industry, which is present in every world region where vine-making is addressed. Among the others, hydrothermal carbonization was chosen as a promising alternative thermochemical process, suitable for the treatment of this high moisture substrate.

Hydrothermal carbonization of off-specification compost: a byproduct of the organic municipal solid waste treatment.

The possibility to apply the hydrothermal carbonization (HTC) process to off-specification compost (EWC 19.05.03) at present landfilled was investigated in this work.

Clay-sewage sludge co-pyrolysis. A TG-MS and Py-GC study on potential advantages afforded by the presence of clay in the pyrolysis of wastewater sewage sludge.

Wastewater sewage sludge was co-pyrolyzed with a well characterized clay sample, in order to evaluate possible advantages in the thermal disposal process of solid waste. Characterization of the co-pyrolysis process was carried out both by thermogravimetric-mass spectrometric (TG-MS) analysis, and by reactor tests, using a lab-scale batch reactor equipped with a gas chromatograph for analysis of the evolved gas phase (Py-GC). Due to the presence of clay, two main effects were observed in the instrumental characterization of the process.