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A Critical Review on Downstream Process to Recovery Succinic Acid from Fermentative Broth
No full textSuccinic acid was a building block chemical of many industrial products, among these, one of the most interesting applications concerns the bioplastics market. This compound can be produced through the biotechnological routes, but several challenges still need to be addressed. One of the greatest challenges has been the downstream process to recover and purify succinic acid from the fermentative broth. Succinic acid must be taken from the fermentation broth, that was composed of various compounds, such as cellular residues, proteins, and other acids, to reach a recovery and a purity >90%, in order to be marketed. Generally, the downstream process can be divided into three phases: pretreatment, separation and purification. Several studies have been carried out on different technologies with the aim to improve recovery and purity. To date, all these methods were applied only on laboratory-scale, due to various critical issues that emerged, such as high costs, which prevented their application on an industrial scale. This review highlighted the best obtained results from the recent studies and discussed on critical aspects and future perspectives on the topic
Advances in Two-Phase Cooling for Next Power Electronics Converters
No full textThis article deals with a comprehensive analysis and performance evaluation of a fully integrated two-phase cooling system for power converters. A suitable test bed has been properly manufactured to perform the experimental campaign for the evaluation of the benefits and to deploy a dedicated management procedure of the two-phase cooling. The system is tested under real operating conditions, in which the system is employed for cooling a 1200-V 100-A insulated-gate bipolar transistor (IGBT) power module of an inverter controlling a permanent magnet synchronous machine. The experimental results show the inverter temperature behavior in start-up for different flow rates of coolant and different temperatures of the fluid on the secondary system. In the steady-state operation, using lower coolant flow rates in the primary circuit achieved equal or even better cooling for the IGBT module compared with higher flow rates. With respect to traditional cooling approaches, the proposed arrangement allows a greater extraction of the heat at a very low flow rate of the cooling fluid, even with standard industrial grade heat sinks, which motivates the use of this cooling technology for the next generation of power electronics converters
Life cycle assessment of leather treatment at various scales: comparison between chrome and vegetable processes
No full textPurpose: This study assesses the environmental performance of all tannery process phases of an Italian artisan tannery, based on primary data, from hides to leather production, and discusses circular pattern options. The study focuses on the potential environmental impact of a traditional artisan company, identifying and evaluating chrome and vegetable tanning options, analysing resource efficiency, and suggesting circular scenarios, to discuss the potential benefits of shifting to a circular perspective. Methods: The life cycle assessment is a standardised framework for evaluating the environmental impact of processes under human control. The study defined the functional unit and system boundary, collected primary and secondary data for the life cycle inventory, and performed life cycle impact assessment using the ReCiPe midpoint hierarchist method. The study identified hotspots within chrome and vegetable tanning options and interpreted the results aiming at providing recommendations for sustainable and circular production pathways. A sensitivity analysis was conducted to estimate the effect of alternative circular scenarios. Results and discussion: The tanning phase is the hotspot for chrome-tanned leather, with the most significant impacts in the Retanning process. For vegetable-tanned leather, the pickling phase is the hotspot with the liming process as the most significant contributor. Both tanning options exhibit significant local emissions, presenting substantial impact potential in water consumption potential during the pickling phase due to the amount of consumed water for the liming process. The vegetable option shows substantial impact reductions, ranging from 20% in ozone depletion potential to 100% in human carcinogenic toxicity potential. Leather production from the circular-vegetable perspective would prevent significant environmental impacts, such as carbon dioxide and 1,4-dichlorobenzene equivalents and saving a considerable amount of water. Conclusions: This study provides reliable and realistic results using primary data, supporting the spread of the circular economy perspective. The vegetable option has substantially reduced impacts due to using natural tanning compounds. Implementing circular patterns achieves even more significant reductions in all impact categories. The shift from local to a national scale and from linear to circular patterns enables maintaining high-quality final products while fulfilling sustainable goals. To promote the circular economy, Italian policy should incentivise the implementation of circular patterns across various scales, extending it to consortium industrial districts and small facilities, support local territories to reduce operational costs of new sustainable installations, overcome risks and barriers of competitive investments, and promote the management of operational information systems to achieve both short-term goals and long-term strategies. Graphical Abstract: [Figure not available: see fulltext.
Preliminary Remote Handling Analysis and Validation of the Electrical Connectors Bridge for the IFMIF-DONES High Flux Test Module
No full textThe International Fusion Materials Irradiation Facility - DEMO-Oriented Neutron Source (IFMIF-DONES) is an innovative accelerator facility aiming to achieve a high-intensity neutron flux for analyzing and qualifying fusion materials. The main objective of IFMIF-DONES is to study the behavior of materials under irradiation conditions compatible with the one expected in the DEMOnstration power plant (DEMO) fusion reactor. To achieve the necessary neutron energy and flux, the IMIF-DONES plant accelerates a deuteron beam on a liquid lithium target in the test cell (TC), reaching a flux value up to 1015 n/s/cm2 with a peak energy of 14 MeV. Due to the high neutron activation of the TC, remote handling (RH) is mandatory to perform the maintenance of the system. Furthermore, the components employed in the TC shall withstand the harsh radioactive environment. The electrical connectors (ECs) of the high flux test module (HFTM) are the critical components of the TC as they communicate all the necessary signals between the HFTM and the IFMIF-DONES facility. The ECs are designed to ease the RH maintenance process using multiconnector plates housed in a metal bridge and use alumina as an insulating material. This article presents the developed ECs and ECs bridge design and the RH validation with a thorough experimental analysis performed at the divertor refurbishment platform (DRP) laboratory of ENEA C. R. Brasimone. The developed ECs and ECs bridge designs proved suitable for RH maintenance. The analysis also showed possible improvements to implement before adoption in IFMIF-DONES
The bidirectional substation for district heating users: experimental performance assessment with operational profiles of prosumer loads and distributed generation
No full textThe regulatory European and national policies outline the role of efficient district heating in achieving mid and long-term decarbonization targets. Prosumers could be equipped with bidirectional exchange substations to increase the local production contribution. The present paper evaluates the contribution of a bidirectional substation in maximizing the use of thermal energy produced locally by renewable sources or waste heat in a densely populated area, considering the limitation due to the non-contemporaneity of production and consumption and possibilities to overcome them. The substation prototype and the control system were tested in operational conditions, assuming the district heating network operating at two temperature levels (80 °C/50 °C and 60 °C/30 °C for supply and return) and applying the hardware-in-the-loop technique for coupling the substation in real-time with data-driven thermal loads (multi-family residential building) and production (solar panels and waste heat) profiles. The various energy flows in the substation are presented for representative days, resulting in a district heating contribution to the user's load ranging between 99.8 % (winter day) and 21.8 % (summer day). The net-metering mechanism was considered, and the assessment extended to the entire year. The local production contribution to the user's load ranges between 24 % and 100 %, depending on the system configuration considered
The chimera of 2D- and 1D-graphene magnetization by hydrogenation or fluorination: critically revisiting old schemes and proposing new ones by ab initio methods
No full textGraphene is an ideal candidate material for spintronics due to its layered structure and peculiar electronic structure. However, in its pristine state, the production of magnetic moments is not trivial. A very appealing approach is the chemical modification of pristine graphene. The main obstacle is the control of the geometrical features and the selectivity of functional groups. The lack of a periodic functionalization pattern of the graphene sheet prevents, therefore, the achievement of long-range magnetic order, thus limiting its use in spintronic devices. In such regards, the stability and the magnitude of the instilled magnetic moment depending on the size and shape of in silico designed graphane islands and ribbons embedded in graphene matrix will be computed and analysed. Our findings thus suggest that a novel and magneto-active graphene derivative nanostructure could become achievable more easily than extended graphone or nanoribbons, with a strong potential for future spintronics applications with a variable spin-current density
Microbial community composition from full-scale reactors treating mature landfill leachate through innovative biological processes and its importance in mathematical modeling
Get PDFThis study investigated the microbial community in two full-scale sequencing batch reactors (SBR) treating mature landfill leachate. Partial nitritation/anammox (PN/A) occurred in SBRA while simultaneous partial nitrification and denitrification (SPND) occurred in SBRB. The taxonomic complexity of bacteria and archaea in samples was assessed at the phylum, class and genus levels using 16 S rRNA-based molecular analyses. Despite the different operating conditions in the SBRs, mainly in terms of DO concentration and SBR cycles, the consortia composition in both reactors was quite similar. However, the relative abundance of the major bacterial groups differed, reflecting the different processes involved. Molecular analyses identified dominant bacteria belonging to AOB, Anammox and denitrifies, allowing to select specific kinetic parameters to be used in mathematical modelling, thus reaching a good data reproduction for both reactors
Metagenomic Analysis during Co-Digestion Buffalo Sludge and Tomato Pomace Post Thermal Stress: A Case Study
No full textThe tomato industry and buffalo farming generate waste, including sludge (BS) and tomato pomace (TP), which can significantly impact their economic and environmental sustainability. The case study tracked changes in microflora composition after a thermal shock during anaerobic co-digestion. The inoculum-to-substrate ratio was 0.5 based on volatile solid content under mesophilic conditions. An Automatic Methane Potential Test System was used to monitor the process before and after thermal stress (50°C) occurred for three days. Next-generation sequencing analyzed the bacterial and archaeal communities. The pH decreased, and methane production plateaued due to the high volatile solid content (87 g/L). After thermal stress, the pH returned to neutral, and the batch resumed biogas production. The cumulative CH4 production reached 3,115 Nml. The biogas had a maximum methane peak of 78.5% compared to 58.4% in BS. The taxonomic classification showed that Firmicutes (51.7%) and Bacteroidetes (29.9%) represented 81.6% of the total OTUs among the bacteria. Fonticella, the most abundant Clostridiaceae (average 4.3%), was absent in BS and increased (up to 17.1%) in TP during methane production. Methanocorpusculum was the most abundant in the archaeal community. However, Metanosarcina showed a stronger correlation with methane production. Brief thermal stress significantly altered bacterial and archaeal populations and allowed to resume biogas production
Fluidized bed reactor sizing using manganese aluminium spinel for thermochemical storage
No full textIn the field of high-temperature thermal energy storage, the use of reacting systems that reversibly decompose and regenerate, absorbing and releasing heat on demand, is becoming more and more attractive. It is essential in the perspective of achieving high thermal energy density storage, appearing potentially suitable for long-term applications too. Thermochemical Systems (TCS) can contribute to increasing the dispatchability of thermal storage, potentially even on a seasonal timescale. So far, most of this field's scientific works have focused on the conventional concept of fixed-bed reactors. To improve the heat transport phenomena involved in TCS storage, a fluidized bed solution was considered in this article. At this aim, a manganese aluminium spinel, which is a low toxic, low pollutant and very cost-effective is proposed for this application. It was synthesized in the form of properly sized (150–200 μm of diameter) particles to be effectively adopted for fluidizing beds. The present work deals with the sizing of the reactor and its coupling with a Concentrating Solar Thermal (CST) system using the Solar Central Receiver (SCR) technology with air as Heat Transfer Fluid (HTF). Imposing realistic boundaries, an optimal configuration was established, with an operating HTF pressure of 4 bar and a thermal discharging power of about 16 MWth. A volumetric energy density of 170 kWhth/m3 was achieved and, despite a relatively low TES reaction enthalpy, the resulting specific cost of 33 €/kWh demonstrates the suitability of this configuration even for the current thermal storage commercial solution, and shows the high potentiality of this type of storage systems
Analysis and Preliminary Design of Primary Heat Exchanger Failure Testing Facility for Lead-Cooled Fast Reactors
No full textThis paper presents an assessment aimed at evaluating primary heat exchanger (PHE) failure of the Westinghouse Electric Company Lead-cooled Fast Reactor (LFR) and at designing a facility for testing phenomena involved in such failure. The system thermal-hydraulic code RELAP5/MOD3.3 was used to develop a transient analysis simulation at reactor scale. Because of RELAP5/MOD3.3’s inability to mix working fluids, the steam injection effect was evaluated using the SIMMER-III code. The limits and strengths of both codes are highlighted throughout the paper. The reactor-scale steady-state results are in good agreement with the nominal operating condition. The transient results show that lead pool surface level variation and primary system pressurization during the PHE failure event are limited. The PHE failure testing facility was characterized, and a preliminary layout was developed. A separate-effects transient inside the vessel was analyzed with SIMMER-III and RELAP5/MOD3.3 runs. The simulation outcomes have provided useful data to inform subsequent design stages for the test facility. Different configurations of the facility have been assessed, highlighting the strengths and weaknesses of each design. The most important issue was identified to be lead pool swelling, reaching the vessel’s lid and blocking the pressure relief vent. This poses a safety hazard that must be addressed and has been raised for resolution in subsequent design stages. The so-called V4 configuration is suggested as a starting point for further improvement of the facility. Furthermore, a smaller failure opening and lower lead level in the vessel are suggested