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Abstract This paper presents a model of a lead-acid battery developed with bond graphs. The bond graph structure is used to reproduce the behavior of reversible electrochemical cells in charging conditions or in discharging conditions. The work presented here has been applied to the particular case of lead-acid battery, so widely used in the automotive industry as standard 12 V batteries and as traction batteries in electrical or hybrid vehicles. The model considers each half-cell independently. For each half-cell the main electrode reaction and the electrolysis reaction of water are considered, that will be the hydrogen evolution reaction in the negative electrode and the oxygen evolution reaction in the positive. Electrochemical principles are considered in order to consider the main phenomena that appear in the battery, like the equilibrium potential, and the overpotential, modeled by means of the activation or charge transfer and the diffusion mechanisms. Each one of this phenomena are modeled with their corresponding bond graph elements and structures, showing the correspondence between bond graph elements and its physical interpretation in this field. First, an isothermal model has been developed in order to show the behavior of the main phenomena. A more complex model has also been developed including thermal behavior. This model is very useful in the case of traction batteries in electrical and hybrid vehicles where high current intensities appear. Some simulation results are also presented in order to show the accuracy of the proposed models and the differences of behavior if thermal effects are considered.

Abstract This paper presents a model of a lead-acid battery developed with bond graphs. The bond graph structure is used to reproduce the behavior of reversible electrochemical cells in charging conditions or in discharging conditions. The work presented here has been applied to the particular case of lead-acid battery, so widely used in the automotive industry as standard 12 V batteries and as traction batteries in electrical or hybrid vehicles. The model considers each half-cell independently. For each half-cell the main electrode reaction and the electrolysis reaction of water are considered, that will be the hydrogen evolution reaction in the negative electrode and the oxygen evolution reaction in the positive. Electrochemical principles are considered in order to consider the main phenomena that appear in the battery, like the equilibrium potential, and the overpotential, modeled by means of the activation or charge transfer and the diffusion mechanisms. Each one of this phenomena are modeled with their corresponding bond graph elements and structures, showing the correspondence between bond graph elements and its physical interpretation in this field. First, an isothermal model has been developed in order to show the behavior of the main phenomena. A more complex model has also been developed including thermal behavior. This model is very useful in the case of traction batteries in electrical and hybrid vehicles where high current intensities appear. Some simulation results are also presented in order to show the accuracy of the proposed models and the differences of behavior if thermal effects are considered.

Abstract The steam gasification of high density polyethylene in continuous mode has been carried out in a conical spouted bed reactor. The effect of temperature (in the 800–900 °C range) and steam/plastic mass ratio (between 0 and 2) on the distribution of products (gas and tar) and their composition has been studied. In order to reduce tar formation, two catalysts have been used in situ, namely, olivine and γ-Al 2 O 3 . The spouted bed reactor has an excellent performance between 850 and 900 °C, and an increase in the steam/plastic ratio from 1 to 2 only improves slightly both carbon conversion efficiency (to 93.6% with steam/plastic ratio = 2) and hydrogen concentration (61.6%). The use of olivine and γ-Al 2 O 3 instead of sand gives way to a moderate reduction in the tar formation , whose yield is 4.8% with olivine. The syngas obtained has a H 2 /CO ratio of 2.2, with a low tar content whose composition (monoaromatics, mainly benzene) augurs well for the use of the syngas in DME synthesis.

Abstract The steam gasification of high density polyethylene in continuous mode has been carried out in a conical spouted bed reactor. The effect of temperature (in the 800–900 °C range) and steam/plastic mass ratio (between 0 and 2) on the distribution of products (gas and tar) and their composition has been studied. In order to reduce tar formation, two catalysts have been used in situ, namely, olivine and γ-Al 2 O 3 . The spouted bed reactor has an excellent performance between 850 and 900 °C, and an increase in the steam/plastic ratio from 1 to 2 only improves slightly both carbon conversion efficiency (to 93.6% with steam/plastic ratio = 2) and hydrogen concentration (61.6%). The use of olivine and γ-Al 2 O 3 instead of sand gives way to a moderate reduction in the tar formation , whose yield is 4.8% with olivine. The syngas obtained has a H 2 /CO ratio of 2.2, with a low tar content whose composition (monoaromatics, mainly benzene) augurs well for the use of the syngas in DME synthesis.

The purpose of this study is to enhance control strategies for selective catalytic reduction (SCR) and ammonia slip catalyst (ASC) systems, aiming to effectively reduce NOx emissions from automotive engines during realistic driving cycles. Despite the effectiveness of these after-treatment systems (ATS), their dynamic and non-linear characteristics present significant challenges in achieving precise control. Therefore, this research proposes a hybrid approach that combines backward induction (BI) as the primary optimization technique with model predictive control (MPC) framework for real-time application. The article introduces a reduced-state control-oriented model of the SCR + ASC system, which is embedded into the BI algorithm to calculate optimal control actions within a finite horizon. Additionally, it is proposed an alternative approach for adapting the grid of model states within the BI algorithm, effectively reducing the computational cost. This adjustment enables the algorithm to operate in real-time with near-optimal results, as confirmed by experimental validation. Lastly, the study explores how different degrees of knowledge regarding system disturbances impact the strategy’s performance, examining three distinct scenarios: constant prediction horizon, probabilistic description, and full knowledge of the prediction horizon.

The purpose of this study is to enhance control strategies for selective catalytic reduction (SCR) and ammonia slip catalyst (ASC) systems, aiming to effectively reduce NOx emissions from automotive engines during realistic driving cycles. Despite the effectiveness of these after-treatment systems (ATS), their dynamic and non-linear characteristics present significant challenges in achieving precise control. Therefore, this research proposes a hybrid approach that combines backward induction (BI) as the primary optimization technique with model predictive control (MPC) framework for real-time application. The article introduces a reduced-state control-oriented model of the SCR + ASC system, which is embedded into the BI algorithm to calculate optimal control actions within a finite horizon. Additionally, it is proposed an alternative approach for adapting the grid of model states within the BI algorithm, effectively reducing the computational cost. This adjustment enables the algorithm to operate in real-time with near-optimal results, as confirmed by experimental validation. Lastly, the study explores how different degrees of knowledge regarding system disturbances impact the strategy’s performance, examining three distinct scenarios: constant prediction horizon, probabilistic description, and full knowledge of the prediction horizon.

A procedure for the design of an aerobic cometabolic process for the on-site degradation of chlorinated solvents in a packed bed reactor was developed using groundwater from an aquifer contaminated by trichloroethylene (TCE) and 1,1,2,2-tetrachloroethane (TeCA). The work led to the selection of butane among five tested growth substrates, and to the development and characterization from the site's indigenous biomass of a suspended-cell consortium capable to degrade TCE (first order constant: 96 L gprotein(-1) day(-1) at 30 °C and 4.3 L gprotein(-1) day(-1) at 15 °C) with a 90 % mineralization of the organic chlorine. The consortium immobilization had strong effects on the butane and TCE degradation rates. The microbial community structure was slightly changed by a temperature shift from 30 to 15 °C, but remarkably affected by biomass adhesion. Given the higher TCE normalized degradation rate (0.59 day(-1) at 15 °C) and attached biomass concentration (0.13 gprotein Lbioreactor(-1) at 15 °C) attained, the porous ceramic carrier Biomax was selected as the best option for the packed bed reactor process. The low TeCA degradation rate exhibited by the developed consortium suggested the inclusion of a chemical pre-treatment based on the TeCA to TCE conversion via β-elimination, a very fast reaction at alkaline pH. To the best of the authors' knowledge, this represents the first attempt to develop a procedure for the development of a packed bed reactor process for the aerobic cometabolism of chlorinated solvents.

A procedure for the design of an aerobic cometabolic process for the on-site degradation of chlorinated solvents in a packed bed reactor was developed using groundwater from an aquifer contaminated by trichloroethylene (TCE) and 1,1,2,2-tetrachloroethane (TeCA). The work led to the selection of butane among five tested growth substrates, and to the development and characterization from the site's indigenous biomass of a suspended-cell consortium capable to degrade TCE (first order constant: 96 L gprotein(-1) day(-1) at 30 °C and 4.3 L gprotein(-1) day(-1) at 15 °C) with a 90 % mineralization of the organic chlorine. The consortium immobilization had strong effects on the butane and TCE degradation rates. The microbial community structure was slightly changed by a temperature shift from 30 to 15 °C, but remarkably affected by biomass adhesion. Given the higher TCE normalized degradation rate (0.59 day(-1) at 15 °C) and attached biomass concentration (0.13 gprotein Lbioreactor(-1) at 15 °C) attained, the porous ceramic carrier Biomax was selected as the best option for the packed bed reactor process. The low TeCA degradation rate exhibited by the developed consortium suggested the inclusion of a chemical pre-treatment based on the TeCA to TCE conversion via β-elimination, a very fast reaction at alkaline pH. To the best of the authors' knowledge, this represents the first attempt to develop a procedure for the development of a packed bed reactor process for the aerobic cometabolism of chlorinated solvents.

Abstract Biofuels are considered as an alternative to partially replace fossil fuels and mitigate climate change effects. A life cycle assessment of second generation ethanol, derived from banana agricultural wastes, was developed to assess its environmental sustainability and demonstrate its capacity of reducing greenhouse gas emissions. The methodological approach was conducted in a Well-to-Wheel perspective, using as functional unit 1 MJ of energy released in the combustion of bioethanol in a passenger car from different bioethanol blends. Primary and secondary information sources were used for the assessment; mass balance and ethanol yield data came from laboratory experimentation. The environmental assessment was carried out using SimaPro 8.0.4.30 with the ReCiPe midpoint (H) impact assessment methodology. The quantified impact categories were climate change (CC), terrestrial acidification (TA), freshwater eutrophication (FE), photochemical oxidant formation (PO), particulate matter formation (PM), and fossil depletion (FD). In addition, net energy value and energy ratio (ER) were analyzed to ensure a positive energy balance. Compared to using pure gasoline, blended gasoline reduced CC, PO, PM, and FD impacts, but increased FE and TA impacts. The obtained energy balance was positive, with an ER of 2.68 MJ/MJ. Wastewater treatment is the process that presented the greatest energy consumption. Since Ecuador is the world's largest exporter of bananas, and a great amount of agricultural waste is available, a case study in this country was analyzed. This case study indicated that Ecuador could use banana residue for ethanol production, considering its positive and negative impacts. In conclusion, second generation ethanol derived from banana agricultural waste has potential to reduce greenhouse gas emissions and fossil depletion and has a positive energy balance.