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Hydrothermal carbonization (HTC) provides an attractive alternative method for the treatment of high-moisture waste and, in particular, digested sludge. HTC could reduce the costs and environmental risks associated with sludge handling and management. Although it is recognized that the dewaterability of hydrochars produced from digested sludge, even at mild temperatures (180–190 °C), is highly improved with respect to the starting material, the filterability of HTC slurries for the recovery of the solid material (hydrochar) still represents a challenge. This study presents the results of an investigation into the filterability of agro-industrial digested sludge HTC slurries produced by a C-700 CarboremTM HTC industrial-scale plant. The filterability of HTC slurries, produced at 190 °C for 1 h, with the use of acid solutions of hydrochloric acid, sulfuric acid or citric acids, was investigated by using a semi-industrial filter press. The use of sulfuric acid or citric acid solutions, in particular, significantly improved the filterability of HTC slurries, reducing the time of filtration and residual moisture content. The acid treatment also promoted the migration of heavy metals and phosphorus (P) in the HTC filtrate solution. This study demonstrates that P can be recovered via the precipitation of struvite in high yields, recovering up to 85 wt% by mass of its initial P content.
Michela Lucian; Fabio Merzari; Michele Gubert; Antonio Messineo; Maurizio Volpe. Industrial-Scale Hydrothermal Carbonization of Agro-Industrial Digested Sludge: Filterability Enhancement and Phosphorus Recovery. Sustainability 2021, 13, 9343 .
AMA StyleMichela Lucian, Fabio Merzari, Michele Gubert, Antonio Messineo, Maurizio Volpe. Industrial-Scale Hydrothermal Carbonization of Agro-Industrial Digested Sludge: Filterability Enhancement and Phosphorus Recovery. Sustainability. 2021; 13 (16):9343.
Chicago/Turabian StyleMichela Lucian; Fabio Merzari; Michele Gubert; Antonio Messineo; Maurizio Volpe. 2021. "Industrial-Scale Hydrothermal Carbonization of Agro-Industrial Digested Sludge: Filterability Enhancement and Phosphorus Recovery." Sustainability 13, no. 16: 9343.
Hydrothermal carbonization (HTC) is considered as an efficient and constantly expanding eco-friendly methodology for thermochemical processing of high moisture waste biomass into solid biofuels and valuable carbonaceous materials. However, during HTC, a considerable amount of organics, initially present in the feedstock, are found in the process water (PW). PW recirculation is attracting an increasing interest in the hydrothermal process field as it offers the potential to increase the carbon recovery yield while increasing hydrochar energy density. PW recirculation can be considered as a viable method for the valorization and reuse of the HTC aqueous phase, both by reducing the amount of additional water used for the process and maximizing energy recovery from the HTC liquid residual fraction. In this work, the effects of PW recirculation, for different starting waste biomasses, on the properties of hydrochars and liquid phase products are reviewed. The mechanism of production and evolution of hydrochar during recirculation steps are discussed, highlighting the possible pathways which could enhance energy and carbon recovery. Challenges of PW recirculation are presented and research opportunities proposed, showing how PW recirculation could increase the economic viability of the process while contributing in mitigating environmental impacts.
Antonio Picone; Maurizio Volpe; Antonio Messineo. Process Water Recirculation during Hydrothermal Carbonization of Waste Biomass: Current Knowledge and Challenges. Energies 2021, 14, 2962 .
AMA StyleAntonio Picone, Maurizio Volpe, Antonio Messineo. Process Water Recirculation during Hydrothermal Carbonization of Waste Biomass: Current Knowledge and Challenges. Energies. 2021; 14 (10):2962.
Chicago/Turabian StyleAntonio Picone; Maurizio Volpe; Antonio Messineo. 2021. "Process Water Recirculation during Hydrothermal Carbonization of Waste Biomass: Current Knowledge and Challenges." Energies 14, no. 10: 2962.
Hydrothermal carbonization (HTC) is a promising thermochemical pre-treatment to convert waste biomass into solid biofuels. However, the process yields large amounts of organic process water (PW), which must be properly disposed of or reused. In this study, the PW produced from the hydrothermal carbonization of lemon peel waste (LP) was recycled into HTC process of LP with the aim of maximize energy recovery from the aqueous phase while saving water resources and mitigating the overall environmental impact of the process. The effects of HTC temperature on the properties of solid and liquid products were investigated during PW recirculation. Experiments were carried out at three different operating temperatures (180, 220, 250 °C), fixed residence times of 60 min, and solid to liquid load of 20 wt%, on a dry basis. Hydrochars were characterized in terms of proximate analysis and higher heating values while liquid phases were analyzed in terms of pH and total organic carbon content (TOC). PW recirculation led to a solid mass yield increase and the effect was more pronounced at lower HTC temperature. The increase of solid mass yield, after recirculation steps (maximum increase of about 6% at 180 °C), also led to a significant energy yield enhancement. Results showed that PW recirculation is a viable strategy for a reduction of water consumption and further carbon recovery; moreover preliminary results encourage for an in-depth analysis of the effects of the PW recirculation for different biomasses and at various operating conditions.
Antonio Picone; Maurizio Volpe; Maria Giustra; Gaetano Di Bella; Antonio Messineo. Hydrothermal Carbonization of Lemon Peel Waste: Preliminary Results on the Effects of Temperature during Process Water Recirculation. Applied System Innovation 2021, 4, 19 .
AMA StyleAntonio Picone, Maurizio Volpe, Maria Giustra, Gaetano Di Bella, Antonio Messineo. Hydrothermal Carbonization of Lemon Peel Waste: Preliminary Results on the Effects of Temperature during Process Water Recirculation. Applied System Innovation. 2021; 4 (1):19.
Chicago/Turabian StyleAntonio Picone; Maurizio Volpe; Maria Giustra; Gaetano Di Bella; Antonio Messineo. 2021. "Hydrothermal Carbonization of Lemon Peel Waste: Preliminary Results on the Effects of Temperature during Process Water Recirculation." Applied System Innovation 4, no. 1: 19.
An increasing number of industrial plants integrate the anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) with a subsequent composting phase. To improve the plant productivity, a fraction of OFMSW digestate can be converted into a carbonaceous material, called hydrocar (HC), through Hydrothermal Carbonization (HTC), and then composted together with the OFMSW digestate itself, to produce “hydrochar co-compost”. The aim of this paper is to present the design and assembly of batch bioreactors, built in-house to investigate the co-composting process of OFMSW digestate and its HC, and to provide some preliminary results. The OFMSW digestate from an industrial plant was carbonized at 200 °C for 3 h in a 2 L HTC reactor, to produce wet HC after filtration. The ratio of OFMSW digestate and green waste (1:1) used as bulking medium was reproduced in four bioreactors with an increasing percentage of HC substituting the OFMSW digestate (0, 25, 50, 75%). The bioreactors managed to effectively compost the solid wet biomasses in a wet environment with temperature and oxygen control, while measuring online the oxygen consumption and thus the dynamic respirometric index (DRI). The DRI24,max measured with AIR-nl solid respirometer (standardized offline measurement) started from values above 800 mg O2 kgVS −1 h−1 before composting and dropped at the end of the process to values in the range 124–340 mg O2 kgVS −1 h−1 for the four mixes, well below the recommended limit of 500 mg O2 kgVS −1 h−1 for high-quality compost stability. These offline DRI values were confirmed by the online DRI measurements. This research is part of the international C2Land Project funded by the European Institute of Innovation and Technology Climate Knowledge and Innovation Community (EIT Climate-KIC), which is greatly acknowledged.
Donato Scrinzi; Gianni Andreottola; Luca Fiori. Composting Hydrochar-OFMSW Digestate Mixtures: Design of Bioreactors and Preliminary Experimental Results. Applied Sciences 2021, 11, 1496 .
AMA StyleDonato Scrinzi, Gianni Andreottola, Luca Fiori. Composting Hydrochar-OFMSW Digestate Mixtures: Design of Bioreactors and Preliminary Experimental Results. Applied Sciences. 2021; 11 (4):1496.
Chicago/Turabian StyleDonato Scrinzi; Gianni Andreottola; Luca Fiori. 2021. "Composting Hydrochar-OFMSW Digestate Mixtures: Design of Bioreactors and Preliminary Experimental Results." Applied Sciences 11, no. 4: 1496.
Hydrothermal carbonization (HTC) is a thermochemical process that can reduce the environmental burdens of wet, heterogeneous biomasses such as the organic fraction of municipal solid waste (OFMSW). Whilst the effect of processing parameters on hydrochar properties is well known, post-treatments to valorize hydrochars are infrequently investigated. Moreover, more severely carbonized hydrochars have a reactive species present on their surface that may limit hydrochars’ use as a solid fuel or soil amendment/environmental adsorbent. To address these potential limitations, a low-temperature (180 °C) thermal treatment and a chemical extraction (1:4 methanol: dichloromethane) were performed on OFMSW hydrochars. The thermal extraction removed up to 12% of this reactive volatile matter, comprised of alkanes, furans, ketones, and fatty acids. Chemical extraction removed up to 61% of the hydrochar, and the extract comprised mostly fatty acids, suggesting a potential pathway for recovery of fatty acids and condensation of fuel molecules in the solid hydrochar. The higher heating values of the extracts were much greater than the non-extractable solid hydrochar. The non-extractable primary char showed similar oxidative and pyrolytic behavior to a standard bituminous coal. The results indicate that HTC could valorize OFMSW by converting this wet waste into a dry solid fuel, soil amendment or environmental adsorbent while simultaneously extracting valuable biodiesel and biofuel precursors. Given increasing legislative pressure to divert OFMSW from landfills, this new pathway offers an alternative to traditional anaerobic digestion management strategies that produce only methane as a green energy product.
Giulia Ischia; Luca Fiori; Lihui Gao; Jillian L. Goldfarb. Valorizing municipal solid waste via integrating hydrothermal carbonization and downstream extraction for biofuel production. Journal of Cleaner Production 2021, 289, 125781 .
AMA StyleGiulia Ischia, Luca Fiori, Lihui Gao, Jillian L. Goldfarb. Valorizing municipal solid waste via integrating hydrothermal carbonization and downstream extraction for biofuel production. Journal of Cleaner Production. 2021; 289 ():125781.
Chicago/Turabian StyleGiulia Ischia; Luca Fiori; Lihui Gao; Jillian L. Goldfarb. 2021. "Valorizing municipal solid waste via integrating hydrothermal carbonization and downstream extraction for biofuel production." Journal of Cleaner Production 289, no. : 125781.
Hydrothermal carbonization (HTC) technology is addressed in the framework of sewage digestate management. HTC converts digestate into a stabilized and sterilized solid (the hydrochar) and a liquor (HTCL) rich in organic carbon. This study aims to optimize the HTC operating parameters, namely the treatment time, in terms of hydrochar production, HTC slurry dewaterability, HTCL bio-methane yields in anaerobic digestion (AD), and process energy consumption. Digestate slurry was processed through HTC at different treatment times (0.5, 1, 2 and 3 h) at 190 °C, and the dewaterability of the treated slurries was addressed through capillary suction time and centrifuge lab-testing. In addition, biochemical methane potential (BMP) tests were conducted for HTCL under mesophilic conditions. Results show that by increasing the HTC treatment time the dewaterability was further improved, ammonium concentration in HTCL increased, and methane potential of HTCL decreased. 0.5 h HTCL had the highest bio-methane potential of 142 ± 3 mL CH4/g COD yet the treatment time was not sufficient for improving the slurry's dewaterability. HTC treatment time of 1 h at 190 °C was identified as the optimum trade-off for improved dewaterability and utilisation of HTCL for biogas production. 1 h HTCL bio-methane potential can cover around 25% of the HTC and AD thermal and electrical energy needs without considering the eventual use of the hydrochar as a biofuel.
Mostafa Ahmed; Gianni Andreottola; Sherien Elagroudy; Mohamed Shaaban Negm; Luca Fiori. Coupling hydrothermal carbonization and anaerobic digestion for sewage digestate management: Influence of hydrothermal treatment time on dewaterability and bio-methane production. Journal of Environmental Management 2021, 281, 111910 .
AMA StyleMostafa Ahmed, Gianni Andreottola, Sherien Elagroudy, Mohamed Shaaban Negm, Luca Fiori. Coupling hydrothermal carbonization and anaerobic digestion for sewage digestate management: Influence of hydrothermal treatment time on dewaterability and bio-methane production. Journal of Environmental Management. 2021; 281 ():111910.
Chicago/Turabian StyleMostafa Ahmed; Gianni Andreottola; Sherien Elagroudy; Mohamed Shaaban Negm; Luca Fiori. 2021. "Coupling hydrothermal carbonization and anaerobic digestion for sewage digestate management: Influence of hydrothermal treatment time on dewaterability and bio-methane production." Journal of Environmental Management 281, no. : 111910.
The present study addresses the coupling of hydrothermal carbonization (HTC) with anaerobic digestion (AD) in wastewater treatment plants. The improvement in biomethane production due to the recycling back to the anaerobic digester of HTC liquor and hydrochar generated from digested sludge is investigated and proved. Mixtures of different compositions of HTC liquor and hydrochar, as well as individual substrates, were tested. The biomethane yield reached 102 ± 3 mL CH4 g−1 COD when the HTC liquor was cycled back to the AD and treated together with primary and secondary sludge. Thus, the biomethane production was almost doubled compared to that of the AD of primary and secondary sludge (55 ± 20 mL CH4 g−1 COD). The benefit is even more significant when both the HTC liquor and the hydrochar were fed to the AD of primary and secondary sludge. The biomethane yield increased up to 187 ± 18 mL CH4 g−1 COD when 45% of hydrochar, with respect to the total feedstock, was added. These results highlight the improvement that the HTC process can bring to AD, enhancing biomethane production and promoting a sustainable solution for the treatment of the HTC liquor and possibly the hydrochar itself.
Roberta Ferrentino; Fabio Merzari; Luca Fiori; Gianni Andreottola. Coupling Hydrothermal Carbonization with Anaerobic Digestion for Sewage Sludge Treatment: Influence of HTC Liquor and Hydrochar on Biomethane Production. Energies 2020, 13, 6262 .
AMA StyleRoberta Ferrentino, Fabio Merzari, Luca Fiori, Gianni Andreottola. Coupling Hydrothermal Carbonization with Anaerobic Digestion for Sewage Sludge Treatment: Influence of HTC Liquor and Hydrochar on Biomethane Production. Energies. 2020; 13 (23):6262.
Chicago/Turabian StyleRoberta Ferrentino; Fabio Merzari; Luca Fiori; Gianni Andreottola. 2020. "Coupling Hydrothermal Carbonization with Anaerobic Digestion for Sewage Sludge Treatment: Influence of HTC Liquor and Hydrochar on Biomethane Production." Energies 13, no. 23: 6262.
Hydrothermal carbonization (HTC) is an emerging path to give a new life to organic waste and residual biomass. Fulfilling the principles of the circular economy, through HTC “unpleasant” organics can be transformed into useful materials and possibly energy carriers. The potential applications of HTC are tremendous and the recent literature is full of investigations. In this context, models capable to predict, simulate and optimize the HTC process, reactors, and plants are engineering tools that can significantly shift HTC research towards innovation by boosting the development of novel enterprises based on HTC technology. This review paper addresses such key-issue: where do we stand regarding the development of these tools? The literature presents many and simplified models to describe the reaction kinetics, some dealing with the process simulation, while few focused on the heart of an HTC system, the reactor. Statistical investigations and some life cycle assessment analyses also appear in the current state of the art. This work examines and analyzes these predicting tools, highlighting their potentialities and limits. Overall, the current models suffer from many aspects, from the lack of data to the intrinsic complexity of HTC reactions and HTC systems. Therefore, the emphasis is given to what is still necessary to make the HTC process duly simulated and therefore implementable on an industrial scale with sufficient predictive margins. Graphic Abstract
Giulia Ischia; Luca Fiori. Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling. Waste and Biomass Valorization 2020, 12, 2797 -2824.
AMA StyleGiulia Ischia, Luca Fiori. Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling. Waste and Biomass Valorization. 2020; 12 (6):2797-2824.
Chicago/Turabian StyleGiulia Ischia; Luca Fiori. 2020. "Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling." Waste and Biomass Valorization 12, no. 6: 2797-2824.
With the increasing needs of clean water supplies, the use of biomass wastes and residues for environmental remediation is essential for environmental sustainability. In this study, the residues from winery and citrus juice industries, namely grape skin and orange peel, respectively, were first converted to hydrochars by hydrothermal carbonization (HTC) and then a cationic dye (methylene blue) adsorption was studied on hydrochars. Hydrochars from both feedstocks were produced at three different temperatures (180, 220, and 250 °C) and a fixed residence time (1 h) to evaluate the hydrochar’s performance on the dye adsorption. The hydrochars were characterized in terms of their pH, pH at point of zero charge (pHPZC), surface functionalities, and surface area. A batch adsorption study of the dye was carried out with variable adsorbate concentration, pH, and temperature. Two adsorption isotherms namely Langmuir and Freundlich models were fitted at 4, 20, and 36 °C. The thermodynamic properties of adsorption (Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS)) were evaluated from the isotherms fittings. Results showed that the dye adsorption on both hydrochars was significant and followed Langmuir isotherm. The maximum adsorption capacity on citrus waste hydrochar was higher than the winery waste hydrochar at any corresponding HTC temperature. Although hydrochars showed the lowest surface area (46.16 ± 0.11 and 34.08 ± 1.23 m2/g for citrus and winery wastes, respectively) at 180 °C, their adsorption was the highest, owing to their maximum density of total oxygen functional groups (23.24 ± 0.22 and 32.69 ± 1.39 µmol/m2 for citrus and winery wastes, respectively), which decreased with the increase in HTC temperature. This research shows a sustainable route for the production of highly effective adsorbent materials at lower HTC temperatures from citrus and winery wastes.
Nepu Saha; Maurizio Volpe; Luca Fiori; Roberto Volpe; Antonio Messineo; M. Toufiq Reza. Cationic Dye Adsorption on Hydrochars of Winery and Citrus Juice Industries Residues: Performance, Mechanism, and Thermodynamics. Energies 2020, 13, 4686 .
AMA StyleNepu Saha, Maurizio Volpe, Luca Fiori, Roberto Volpe, Antonio Messineo, M. Toufiq Reza. Cationic Dye Adsorption on Hydrochars of Winery and Citrus Juice Industries Residues: Performance, Mechanism, and Thermodynamics. Energies. 2020; 13 (18):4686.
Chicago/Turabian StyleNepu Saha; Maurizio Volpe; Luca Fiori; Roberto Volpe; Antonio Messineo; M. Toufiq Reza. 2020. "Cationic Dye Adsorption on Hydrochars of Winery and Citrus Juice Industries Residues: Performance, Mechanism, and Thermodynamics." Energies 13, no. 18: 4686.
The growing importance of bio-based products, combined with the desire to decrease the production of wastes, boosts the necessity to use wastes as raw materials for bio-based products. A waste material with a large potential is spent sugar beets, which are mainly used as animal feeds or fertilizers. After hydrothermal treatment, the produced chars exhibited an H/C ratio of 1.2 and a higher heating value of 22.7 MJ/kg, which were similar to that of subbituminous coal and higher than that of lignite. Moreover, the treatment of 25 g/L of glucose and 22 g/L of fructose by heating up to 160 °C led to a possible application of spent sugar beets for the production of 5-hydroxymethylfurfural. In the present study, the maximum concentration of 5-hydroxymethylfurfural was 3.4 g/L after heating up to 200 °C.
Jens Pfersich; Pablo J. Arauzo; Michela Lucian; Pierpaolo Modugno; Maria-Magdalena Titirici; Luca Fiori; Andrea Kruse. Hydrothermal Conversion of Spent Sugar Beets into High-Value Platform Molecules. Molecules 2020, 25, 3914 .
AMA StyleJens Pfersich, Pablo J. Arauzo, Michela Lucian, Pierpaolo Modugno, Maria-Magdalena Titirici, Luca Fiori, Andrea Kruse. Hydrothermal Conversion of Spent Sugar Beets into High-Value Platform Molecules. Molecules. 2020; 25 (17):3914.
Chicago/Turabian StyleJens Pfersich; Pablo J. Arauzo; Michela Lucian; Pierpaolo Modugno; Maria-Magdalena Titirici; Luca Fiori; Andrea Kruse. 2020. "Hydrothermal Conversion of Spent Sugar Beets into High-Value Platform Molecules." Molecules 25, no. 17: 3914.
Hydrothermal carbonization (HTC) represents an efficient and valuable pre-treatment technology to convert waste biomass into highly dense carbonaceous materials that could be used in a wide range of applications between energy, environment, soil improvement and nutrients recovery fields. HTC converts residual organic materials into a solid high energy dense material (hydrochar) and a liquid residue where the most volatile and oxygenated compounds (mainly furans and organic acids) concentrate during reaction. Pristine hydrochar is mainly used for direct combustion, to generate heat or electricity, but highly porous carbonaceous media for energy storage or for adsorption of pollutants applications can be also obtained through a further activation stage. HTC process can be used to enhance recovery of nutrients as nitrogen and phosphorous in particular and can be used as soil conditioner, to favor plant growth and mitigate desertification of soils. The present review proposes an outlook of the several possible applications of hydrochar produced from any sort of waste biomass sources. For each of the applications proposed, the main operative parameters that mostly affect the hydrochar properties and characteristics are highlighted, in order to match the needs for the specific application.
Manfredi Picciotto Maniscalco; Maurizio Volpe; Antonio Messineo. Hydrothermal Carbonization as a Valuable Tool for Energy and Environmental Applications: A Review. Energies 2020, 13, 4098 .
AMA StyleManfredi Picciotto Maniscalco, Maurizio Volpe, Antonio Messineo. Hydrothermal Carbonization as a Valuable Tool for Energy and Environmental Applications: A Review. Energies. 2020; 13 (16):4098.
Chicago/Turabian StyleManfredi Picciotto Maniscalco; Maurizio Volpe; Antonio Messineo. 2020. "Hydrothermal Carbonization as a Valuable Tool for Energy and Environmental Applications: A Review." Energies 13, no. 16: 4098.
Conventional activated sludge systems, still widely used to treat wastewater, produce large amounts of solid waste that is commonly landfilled or incinerated. This study addresses the potential use of Hydrothermal Carbonization (HTC) to valorize sewage sludge residues examining the properties of hydrochars depending on HTC process conditions and sewage sludge withdrawal point. With increasing HTC severity (process residence time and temperature), solid yield, total Chemical Oxygen Demand (COD) and solid pH decrease while ash content increases. Hydrochars produced from primary (thickened) and secondary (digested and dewatered) sludge show peculiar distinct properties. Hydrochars produced from thickened sludge show good fuel properties in terms of Higher Heating Value (HHV) and reduced ash content. However, relatively high volatile matter and O:C and H:C ratios result in thermal reactivity significantly higher than typical coals. Both series of carbonized secondary sludges show neutral pH, low COD, enhanced phosphorous content and low heavy metals concentration: as a whole, they show properties compatible with their use as soil amendments.
Fabio Merzari; Jillian Goldfarb; Gianni Andreottola; Tanja Mimmo; Maurizio Volpe; Luca Fiori. Hydrothermal Carbonization as a Strategy for Sewage Sludge Management: Influence of Process Withdrawal Point on Hydrochar Properties. Energies 2020, 13, 2890 .
AMA StyleFabio Merzari, Jillian Goldfarb, Gianni Andreottola, Tanja Mimmo, Maurizio Volpe, Luca Fiori. Hydrothermal Carbonization as a Strategy for Sewage Sludge Management: Influence of Process Withdrawal Point on Hydrochar Properties. Energies. 2020; 13 (11):2890.
Chicago/Turabian StyleFabio Merzari; Jillian Goldfarb; Gianni Andreottola; Tanja Mimmo; Maurizio Volpe; Luca Fiori. 2020. "Hydrothermal Carbonization as a Strategy for Sewage Sludge Management: Influence of Process Withdrawal Point on Hydrochar Properties." Energies 13, no. 11: 2890.
In fixed-bed pyrolysis reactors, the stacking of sample particles often leads to higher yields of solid pyrolysis products (chars) than are obtained from other types of reactors. This phenomenon is particularly emphasised in thermogravimetric (TG) balances, which unlike many fixed-bed reactors, do not sweep gas through the stationary bed of pyrolysing sample. Gas is swept through the sample bed to reduce the residence time of tar vapours in close proximity to chars, which affects the extent to which these vapours will condense onto the surface of chars and repolymerise, thus increasing char yield. Depth of the sample bed affects this residence time, and thus affects char yield. In this work, the sensitivity of typical analyses of biomass thermogravimetry to variations in bed depth have been assessed. Results of these analyses, including product distributions, proximate compositions, and kinetic predictions, carried out on microcrystalline cellulose and birch wood hydrochar samples produced at temperatures ranging from 160 to 280 °C, have been shown to be sensitive to variations in bed depth, and it has been demonstrated that this sensitivity is amplified at higher heating rates and temperatures. Thus, when a single sample mass is used for any of these typical TG analyses, as is common in published literature, the results are not fundamental properties of the material tested but rather a product of the exact experimental design employed. Future work is needed to identify reactor and experimental design guidelines to minimise this sensitivity in fixed-bed reactors.
Meredith Barr; Maurizio Volpe; Antonio Messineo; Roberto Volpe. On the suitability of thermogravimetric balances for the study of biomass pyrolysis. Fuel 2020, 276, 118069 .
AMA StyleMeredith Barr, Maurizio Volpe, Antonio Messineo, Roberto Volpe. On the suitability of thermogravimetric balances for the study of biomass pyrolysis. Fuel. 2020; 276 ():118069.
Chicago/Turabian StyleMeredith Barr; Maurizio Volpe; Antonio Messineo; Roberto Volpe. 2020. "On the suitability of thermogravimetric balances for the study of biomass pyrolysis." Fuel 276, no. : 118069.
Municipal sewage sludge was subjected to a hydrothermal carbonization (HTC) process for developing a hydrochar with high adsorption capacity for water remediation in terms of dye removal. Three hydrochars were produced from municipal sewage sludge by performing HTC at 190, 220 and 250 °C, with a 3 h reaction time. Moreover, a portion of each hydrochar was subjected to a post-treatment with KOH in order to increase the adsorption capacity. Physicochemical properties of sludge samples, raw hydrochars and KOH-modified hydrochars were measured and batch adsorption studies were performed using methylene blue (MB) as a reference dye. Data revealed that both raw and modified hydrochars reached good MB removal efficiency for solutions with low MB concentrations; on the contrary, MB in high concentration solutions was efficiently removed only by modified hydrochars. Interestingly, the KOH treatment greatly improved the MB adsorption rate; the modified hydrochars were capable of capturing above 95% of the initial MB amount in less than 15 min. The physicochemical characterization indicates that alkali modification caused a change in the hydrochar surface making it more chemically homogeneous, which is particularly evident for the 250 °C hydrochar. Thus, the adsorption process can be regarded as a complex result of various phenomena, including physi- and chemi-sorption, acid–base and redox equilibria.
Roberta Ferrentino; Riccardo Ceccato; Valentina Marchetti; Gianni Andreottola; Luca Fiori. Sewage Sludge Hydrochar: An Option for Removal of Methylene Blue from Wastewater. Applied Sciences 2020, 10, 3445 .
AMA StyleRoberta Ferrentino, Riccardo Ceccato, Valentina Marchetti, Gianni Andreottola, Luca Fiori. Sewage Sludge Hydrochar: An Option for Removal of Methylene Blue from Wastewater. Applied Sciences. 2020; 10 (10):3445.
Chicago/Turabian StyleRoberta Ferrentino; Riccardo Ceccato; Valentina Marchetti; Gianni Andreottola; Luca Fiori. 2020. "Sewage Sludge Hydrochar: An Option for Removal of Methylene Blue from Wastewater." Applied Sciences 10, no. 10: 3445.
Research around hydrothermal carbonization (HTC) has seen a huge development in recent years, materializing in the first pilot and industrial plants. Even though HTC reactions are slightly exothermic, the overall process entails energy consumption to both reach operating conditions and tackle heat losses. To face this issue and to develop a zero-energy process, this work proposes an innovative solution: the coupling of an HTC reactor with a solar concentrator, designed to fully cover the HTC energy needs. A 300 ml stainless steel HTC reactor was constructed and positioned on the focus of a parabolic dish concentrator (PDC), consisting of one parabolic mirror of 0.8 m2. To maximize the light absorption, the illuminated side of the HTC reactor was coated with a thin layer of nanostructured copper oxide, realized via electron beam deposition. Then, the effectiveness of the hybrid solar-HTC solution was demonstrated by carrying out an experimental campaign on a residual agro-biomass (grape seeds), which was treated at 180, 220, and 250 °C for 2 h. The coating confers excellent absorbing performances to the system, exhibiting an absorptance of up to 95.6% (at 300 nm wavelength). Heating times, yields, composition, and energy properties of “solar hydrochars” resemble those of studies performed in traditional HTC systems. This research work proves the feasibility of the solar-HTC prototype apparatus and opens the way to the development of a zero-energy solar-HTC technology.
Giulia Ischia; Michele Orlandi; Murilo Alexandre Fendrich; Marco Bettonte; Fabio Merzari; Antonio Miotello; Luca Fiori. Realization of a solar hydrothermal carbonization reactor: A zero-energy technology for waste biomass valorization. Journal of Environmental Management 2020, 259, 110067 .
AMA StyleGiulia Ischia, Michele Orlandi, Murilo Alexandre Fendrich, Marco Bettonte, Fabio Merzari, Antonio Miotello, Luca Fiori. Realization of a solar hydrothermal carbonization reactor: A zero-energy technology for waste biomass valorization. Journal of Environmental Management. 2020; 259 ():110067.
Chicago/Turabian StyleGiulia Ischia; Michele Orlandi; Murilo Alexandre Fendrich; Marco Bettonte; Fabio Merzari; Antonio Miotello; Luca Fiori. 2020. "Realization of a solar hydrothermal carbonization reactor: A zero-energy technology for waste biomass valorization." Journal of Environmental Management 259, no. : 110067.
Roberto Volpe; José Miguel Bermudez Menendez; Tomas Ramirez Reina; Maurizio Volpe; Antonio Messineo; Marcos Millan; Maria-Magdalena Titirici. Free radicals formation on thermally decomposed biomass. Fuel 2019, 255, 1 .
AMA StyleRoberto Volpe, José Miguel Bermudez Menendez, Tomas Ramirez Reina, Maurizio Volpe, Antonio Messineo, Marcos Millan, Maria-Magdalena Titirici. Free radicals formation on thermally decomposed biomass. Fuel. 2019; 255 ():1.
Chicago/Turabian StyleRoberto Volpe; José Miguel Bermudez Menendez; Tomas Ramirez Reina; Maurizio Volpe; Antonio Messineo; Marcos Millan; Maria-Magdalena Titirici. 2019. "Free radicals formation on thermally decomposed biomass." Fuel 255, no. : 1.
This study evaluates the effects of thermal hydrolysis (TH) pretreatment on anaerobic digestion (AD), through results obtained by biochemical methane potential (BMP) tests under mesophilic conditions (35 °C). Thickened sludge from a wastewater treatment plant (WWTP) was thermally treated under two different temperatures (150 and 170 °C) and reaction times (30 and 60 min). Results show a significant increase in soluble COD, compared with the untreated sludge, when sludge was treated at 170 °C for 60 min. Moreover, the following BMP tests point out that TH pretreatment of sludge accelerated the AD rate and increased the biogas yield contributing to an increase in methane production, ranging between 17 and 24% compared with the raw sludge. Furthermore, the hydrolysis constant was estimated and methane production and degree of disintegration of the TH pretreated sludge were correlated, in order to deep the knowledge on the hydrolysis as the AD rate-limiting step. Further, the combined effects of TH pretreatment and AD on sludge show a reduction of total and volatile solids up to 19% and 24%, respectively.
Roberta Ferrentino; Fabio Merzari; Luca Fiori; Gianni Andreottola. Biochemical Methane Potential Tests to Evaluate Anaerobic Digestion Enhancement by Thermal Hydrolysis Pretreatment. BioEnergy Research 2019, 12, 722 -732.
AMA StyleRoberta Ferrentino, Fabio Merzari, Luca Fiori, Gianni Andreottola. Biochemical Methane Potential Tests to Evaluate Anaerobic Digestion Enhancement by Thermal Hydrolysis Pretreatment. BioEnergy Research. 2019; 12 (3):722-732.
Chicago/Turabian StyleRoberta Ferrentino; Fabio Merzari; Luca Fiori; Gianni Andreottola. 2019. "Biochemical Methane Potential Tests to Evaluate Anaerobic Digestion Enhancement by Thermal Hydrolysis Pretreatment." BioEnergy Research 12, no. 3: 722-732.
Olive trimmings (OT) were used as feedstock for an in-depth experimental study on the reaction kinetics controlling hydrothermal carbonization (HTC). OT were hydrothermally carbonized for a residence time τ of up to 8 h at temperatures between 180 and 250 °C to systematically investigate the chemical and energy properties changes of hydrochars during HTC. Additional experiments at 120 and 150 °C at τ = 0 h were carried out to analyze the heat-up transient phase required to reach the HTC set-point temperature. Furthermore, an original HTC reaction kinetics model was developed. The HTC reaction pathway was described through a lumped model, in which biomass is converted into solid (distinguished between primary and secondary char), liquid, and gaseous products. The kinetics model, written in MATLABTM, was used in best fitting routines with HTC experimental data obtained using OT and two other agro-wastes previously tested: grape marc and Opuntia Ficus Indica. The HTC kinetics model effectively predicts carbon distribution among HTC products versus time with the thermal transient phase included; it represents an effective tool for R&D in the HTC field. Importantly, both modeling and experimental data suggest that already during the heat-up phase, biomass greatly carbonizes, in particular at the highest temperature tested of 250 °C.
Michela Lucian; Maurizio Volpe; Luca Fiori. Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling. Energies 2019, 12, 516 .
AMA StyleMichela Lucian, Maurizio Volpe, Luca Fiori. Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling. Energies. 2019; 12 (3):516.
Chicago/Turabian StyleMichela Lucian; Maurizio Volpe; Luca Fiori. 2019. "Hydrothermal Carbonization Kinetics of Lignocellulosic Agro-Wastes: Experimental Data and Modeling." Energies 12, no. 3: 516.
Fabio Merzari; Michela Langone; Gianni Andreottola; Luca Fiori. Methane production from process water of sewage sludge hydrothermal carbonization. A review. Valorising sludge through hydrothermal carbonization. Critical Reviews in Environmental Science and Technology 2019, 49, 947 -988.
AMA StyleFabio Merzari, Michela Langone, Gianni Andreottola, Luca Fiori. Methane production from process water of sewage sludge hydrothermal carbonization. A review. Valorising sludge through hydrothermal carbonization. Critical Reviews in Environmental Science and Technology. 2019; 49 (11):947-988.
Chicago/Turabian StyleFabio Merzari; Michela Langone; Gianni Andreottola; Luca Fiori. 2019. "Methane production from process water of sewage sludge hydrothermal carbonization. A review. Valorising sludge through hydrothermal carbonization." Critical Reviews in Environmental Science and Technology 49, no. 11: 947-988.
Kurabachew Duba; Luca Fiori. Supercritical CO 2 extraction of grape seeds oil: scale‐up and economic analysis. International Journal of Food Science & Technology 2019, 54, 1306 -1312.
AMA StyleKurabachew Duba, Luca Fiori. Supercritical CO 2 extraction of grape seeds oil: scale‐up and economic analysis. International Journal of Food Science & Technology. 2019; 54 (4):1306-1312.
Chicago/Turabian StyleKurabachew Duba; Luca Fiori. 2019. "Supercritical CO 2 extraction of grape seeds oil: scale‐up and economic analysis." International Journal of Food Science & Technology 54, no. 4: 1306-1312.