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• Process modeling is developed to assess performance of lithium-ion battery recycling. • Pyrometallurgical and hydrometallurgical processes are simulated via mass balances. • Recycling indicators assessing material recoveries and quality are introduced. • Effect of share of battery chemistries and formats in the feed is evaluated. • Critical unit operations are identified via sensitivity to process parameters. In the shift toward sustainable energy solutions, the efficiency of lithium-ion battery (LIB) recycling within the supply chain is of paramount importance. This study evaluates the performance of LIB recycling processes by advancing a quantitative modeling approach. Through process simulations, a comprehensive assessment of pyrometallurgical and hydrometallurgical LIB recycling processes is presented by focusing on the key parameters that influence material recoveries and yields. Recycling efficiency indicators, accounting for the quantity and quality of recycled materials, are introduced and their dependence on the share of different battery chemistries and formats in the spent batteries feed is assessed via numerical simulations. A sensitivity analysis of process parameters identifies the unit operations mostly affecting the recycling performance, highlighting process criticalities. The model presented and its outcomes provide a valuable guide for stakeholders in the LIB industry, aiding informed decision-making to enhance sustainability and resource recovery in the ecosystem of electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Abstract The increment in the world energy consumption and the necessity for a sustainable industrial production, indicate that renewable resources may be key actors for future development. In this scenario, biomass appears fundamental for the smooth transition from fossil fuels to lower carbon footprint technologies, and as a moderator agent within the renewable market. The small size biomass combustion application appears as suitable for smart grid and distributed generation applications, but it is necessary to improve the design tools capabilities and the experimental knowledge of these systems. The present work aims at investigating the thermal behaviour of a 140 kW fixed-bed boiler sited at the Biomass to Energy Research Centre (CRIBE) of the University of Pisa and fed with woodchips. Experimental activities were conducted in order to acquire thermal and chemical data. Moreover, a computational fluid dynamic model was developed and validated. Attention was paid to the fixed bed analysis, and the results showed a good model prediction capability, with respect to the reduced computational demand required. [ABSTRACT FROM AUTHOR]

The char oxidation of a torrefied biomass and its parent material was carried out in an isothermal plug flow reactor (IPFR), which is able to rapidly heat the biomass particles to a maximum temperature of 1400 °C at a heating rate of 10 4 °C/s, similar to the real conditions found in power plant furnaces. During each char oxidation test, the residues of biomass particles were collected and analyzed to determine the weight loss based on the ash tracer method. According to the experimental results, it can be concluded that chars produced from a torrefied biomass are less reactive than the ones produced, under the same conditions, from its raw material. The apparent kinetics of the torrefied biomass and its parent material are determined by minimizing the difference between the modeled and the experimental results. The predicted weight loss during char oxidation, using the determined kinetics, agrees well with experimental results. [ABSTRACT FROM AUTHOR]

Abstract: The influence of concentration of oxygen on the oxidation rates of 5 anthracite chars is investigated at gas temperatures ranging from 1223K to 1673K. Reaction orders and kinetic parameters are determined with a multivariable optimization method in which modeled burnout profiles are fitted to experimental burnout profiles from a 4m isothermal plug flow reactor operating at industrially realistic heating rates, i.e., 104–105 K/s. The determined reaction orders are compared to reaction orders of 10 bituminous coal chars investigated at similar conditions in a previous study. The results show that the optimized reaction order of the anthracite chars is zero, while the reaction order of the bituminous coal char is one. The difference in the reaction orders cannot be explained by using the two semi-global oxidation reactions: C(O)+O2 →CO/CO2 and C(O)→CO. However, by also considering 2C(O)→CO2 +C as a possible reaction step, the reaction order difference between the anthracite chars and the bituminous coal chars can be explained. In addition, a first attempt to apply the same multivariable optimization method to determine the reaction order for a biomass char is presented. [Copyright &y& Elsevier]

Abstract: This paper reports part of the results of the campaigns performed on a low NO x burner, firing natural gas in oxy-fuel conditions. The results of combustion tests on burning natural gas with different flue gas recycle rates are presented, with a particular emphasis on NO x production that might affect retrofitting of oxy-fuel technology in conventional boilers. The process and flame characterisation performed on natural gas provides a valuable set of experimental data for the technological development of oxy-combustion burner technology with recycled flue gas, especially in retrofitting scenarios. The data can be used to develop a better understanding of the chemical and physical phenomena involved in oxy-fuel combustion and can provide modellers with a valuable hint for the development of specific sub-models for oxy-combustion simulation. Since is seems technologically unfeasible to reduce down to zero the presence of nitrogen in recycled flue gases, due to air in-leakages, the presence of relatively small amounts of nitrogen in crucial location in the burner provides a thermal NO x source, depending on local levels of temperature and oxygen concentration. [ABSTRACT FROM AUTHOR]

Abstract: The direct implementation into CFD codes of large kinetic mechanisms for the prediction of pollutant emissions is still unfeasible, due to computer time limitations which become particularly relevant when considering the typical scale of the industrial applications. Therefore, simplified modeling approaches are generally adopted, as they allow reducing the computational effort associated with the numerical simulations. With regard to NO formation, simple one-step mechanisms are used to describe each of the relevant routes contributing to the overall generation of NO, i.e., thermal, prompt. The main drawback associated to a simplified NO formation approach lies, however, in the extreme sensitivity of the lumped rates on the thermo chemical state which define the combustion system of interest. Then, a proper description of turbulence/chemistry interactions must be employed in the CFD model, to provide a realistic background for the estimation of NO emissions. This becomes particularly important in MILD combustion regime, which generally requires an accurate description of the gas-phase oxidation, due to the kinetic control on the overall combustion process. The present paper discusses key aspects and requisite for predicting NO formation in MILD combustion regime. The approach is based on the direct coupling of simplified NO mechanisms to the CFD calculation and is applied to different MILD conditions. Simulations are carried out for a set of experimental runs performed on a self-recuperative MILD burner, varying the hydrogen content in the fuel stream from 0% up to 50% by wt. [ABSTRACT FROM AUTHOR]

Abstract: Moderate or Intense Low oxygen Dilution (MILD) combustion is particularly appealing for coupling very high combustion efficiencies with very low pollutant emissions. Experimental and numerical studies have been devoted to MILD combustion. However, fundamental aspects of such combustion regime are still not completely understood and this generates uncertainties, especially from the modeling perspective. A novel methodology based on Principal Component Analysis (PCA) is proposed for the investigation of the main features characterizing the MILD combustion regime. High fidelity experimental datasets of CH4/H2 flames propagating into a hot and diluted co-flow are employed to this purpose. Results indicate that the proposed methodology can provide progress variables which coherently follow the modification of the flame structure experimentally observed at different levels of oxygen dilution in the co-flow. A local PCA approach is also proposed, based on the partition of the data sets into cluster, followed by the local application of PCA. Such approach ensures that the low-dimensional projection is characterized by the minimum parameterization error. Results indicate that local PCA leads to the identification of regions of the flow characterized by different physical processes, thus allowing the determination of optimal progress variables in each of them. [ABSTRACT FROM AUTHOR]

Abstract: Data on biomass chars obtained under conditions similar to those of practical applications (high heating rate and low residence time) are required for co-combustion and gasification plants. A methodological procedure is developed and applied to two biomass fuels (cacao shells and olive cake) for producing high heating rate chars and characterizing their reactivity and morphology after the first steps of devolatilization. Different chars are produced in a drop tube reactor (rapid pyrolysis) by varying the nominal temperature and the residence time. Oxidation in air is performed to compare typical temperatures and kinetic parameters and evaluate the effect of the operating conditions on char reactivity. A detailed SEM analysis allows to assess the structural variations during the pyrolysis and detect the main phenomena (softening, swelling, melting, formation of bubbles). A quantitative morphological study is also performed to provide size and shape (important for biomasses) distributions of the parent fuel and the chars. These data are more significant than average values in advanced model to correctly simulate the fluid dynamic behaviour of each dimensional class of particles in large scale furnaces and gasifiers and predict a more reliable residence time of the particles. [Copyright &y& Elsevier]

Abstract: A novel methodology based on principal component analysis (PCA) was developed for the identification of the low-dimensional manifold of a chemical reacting system, the determination of its dimensionality and the selection of optimal manifold variables. Results are presented for a simple CO/H2/N2 jet flame and for a CH4 piloted flame (TNF Flame F). Results of the global PCA analysis (GPCA) on the whole data sets show that, in all cases, the number of modes required to reproduce the different state variables is a strong function of the physical processes by which the variables themselves are affected. As a result, a greater dimensionality is observed for the piloted flame, characterized by significant extinction. A local PCA (LPCA) algorithm, VQPCA, was also employed to reduce the effect of non-linear dependencies among state variables on the manifold dimension determination. By applying VQPCA, the data were divided into separated clusters, by using an unsupervised partitioning algorithm based on reconstruction error minimization. Also, results from VQPCA were compared with those obtained with an approach based on mixture fraction conditioning (FPCA). Both approaches are comparable for the CO/H2/N2 flame, while VQPCA performances are superior to FPCA for the CH4 flame, due to its higher complexity. [Copyright &y& Elsevier]

Abstract: Important advantages in the use of alternative and renewable fuels (CO2 reduction in the atmosphere, recovery of energy from wastes, limited SO x , NO x and heavy metal emissions) can be obtained only by solving technological and economical problems that make direct combustion of such fuels impractical. This is possible after a detailed investigation to determine the most important features of these materials in all steps of the thermal process. At present, few data can actually be found for the char properties of these fuels. Nevertheless, the knowledge of properties of chars (especially after severe devolatilization) is crucial for both modeling purposes (reactivity, kinetics of combustion and gasification, morphology variations, composition, and fate of pollutant precursors) and practical applications (boiler efficiency, ash deposition, and condensation causing fouling and slagging problems). This work deals with the characterization of chars from different classes of materials (biomasses, waste, and low and high volatile matter (VM) coals) obtained after a devolatilization performed in severe thermal conditions, i.e., high temperature and high heating rate. A methodological approach is developed, applied, and discussed, using an electrodynamic balance that is a versatile analyzer for the study of properties of single levitated particles. The specific heat, size, and shape distribution, and density variation between the char and the parent material are evaluated for all materials. Scanning electron microscopy (SEM) analysis is also carried out to investigate morphological variations and support the major results obtained with the electrodynamic analyzer. [Copyright &y& Elsevier]

This paper presents result from an economic and technical point of view evaluation study, which has sought to establish the potential for replacing well-water that is currently used at the Piaggio industrial plant in Pontedera with recycled wastewater. The study is based upon a pilot wastewater treatment plant, which has been used to test wastewater treatment processes and to compare with achieved quality of recycled waters with that of water drawn on-site from physical/chemical pre-treatment and end with a reverse osmosis and air stripping stage. However, after the physical/chemical pre-treatment, the first option uses oxidation with ozone followed by activated carbon filtration, whereas the second method uses ultrafiltration. The first method is more effective at reducing chemical oxygen demand (COD) whereas the second method is more effective in removing bacteria. Nonetheless, both methods deliver water for re-use of a quality comparable with or better than that of well-water. In principle, the reverse osmosis permeate from either process could be re-used in all production phases at the industrial plant. However, the method base upon oxidation with ozone followed by activated carbon filtration is preferred, because, the process is simpler and continuous. The economic analysis of this process gives an estimated cost of Euro 0.55 per m3 for treated water. This compares favorably with other treatment processes and with the cost of other forms of water supply, which are projected to increase in any case. [Copyright &y& Elsevier]