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This paper proposes a new continuous two phase bioreactor (C-TPPB) configuration for the removal and degradation of xenobiotic compounds from wastewaters. The reactor is made of three principal parts: a tube side in which the wastewater flows; a polymeric membrane which constitutes the tube walls; a shell side, set as a continuous stirred tank reactor (CSTR), in which the xenobiotics are degraded by means of a bacterial population. A mathematical model for the system description was developed and validated by means of fitting using literature experimental data obtained from a similar configuration. Since the nature of the fitting parameters did not depend upon the particular set-up, such validation procedure was possible. A dimensionless analysis was also carried out by defining a modified Stenton (St’) and Damkohler (Da’) number in order to detect the C-TTPB design criteria. The removal of 4-NtiroPhenol was reported as a case study and an algorithm for a preliminary design procedure was developed.

An innovative steam methane reforming for pure hydrogen production with molten salts as heat transfer fluid has been analyzed validating experimental data by means of a mathematical model. The technology, developed in the project CoMETHy and realized on a pilot scale at the ENEA-Casaccia research center, is based on a steam-reforming reactor with a structured open foam catalyst and Pd-based membranes, both integrated in the reaction environment to improve the reactor performance. The pilot plant allowed the production of ≥3 Nm 3 / h of pure hydrogen, achieving an overall methane conversion of 60% at

This work focuses on a new mathematical model which describes the gastro-intestinal absorption of drugs and the effect of food interactions on drugs bioavailability. The model structure consists of five compartments (stomach, duodenum, jejunum feeding, intestine and blood) simulated though different in-series reactors. All the enzymatic reactions taking place in the gastro-intestinal system are described through the Michaelis–Menten kinetic equations. The model has been tested for drug administration (paracetamol and ketoprofen) with and without the meal digestion. The model has been validated through pharmacokinetics curves obtained from in vivo tests (reported in the literature) and used to simulate the drug absorption dynamics in different conditions. The maximum blood concentration were 0.153 mmol L−1 and 0.0243 mmol L−1, respectively for paracetamol and ketoprofen. The time to reach the maximum concentration for the paracetamol and ketoprofen was around 55 min. In case of contemporary meal digestion, the maximum concentration of paracetamol in the blood was 0.100 mmol L−1 and 0.0135 mmol L−1 for ketoprofen; the time to reach the maximum concentration was 3 h and 45 min for paracetamol and 3 h and 35 min for ketoprofen. The drugs showed different pharmacokinetics, in agreement with the literature, during the digestion of food. To show the predictive capacity of the model, the simulations were also compared against additional experimental data (obtained from in vivo tests available in the literature) relative to ketoprofen administration with food.

Molten salts eutectics are promising candidates as phase change materials (PCMs) for thermal storage applications, especially considering the possibility to store and release heat at high temperatures. Although many compounds have been proposed for this purpose in the scientific literature, very few data are available regarding actual applications. In particular, there is a lack of information concerning thermal storage at temperatures around 600 °C, necessary for the coupling with a highly efficient Rankine cycle powered by concentrated solar power (CSP) plants. In this contest, the present work deals with a thermophysical behavior investigation of a storage heat exchanger containing a cost-effective and safe ternary eutectic, consisting of sodium chloride, potassium chloride, and sodium carbonate. This material was preliminarily and properly selected and characterized to comply with the necessary melting temperature and latent enthalpy. Then, an indirect heat exchanger was considered for the simulation, assuming aluminum capsules to confine the PCM, thus obtaining the maximum possible heat exchange surface and air at 5 bar as heat transfer fluid (HTF). The modelling was carried out setting the inlet and outlet air temperatures at, respectively, 290 °C and 550 °C, obtaining a realistic storage efficiency of around 0.6. Finally, a conservative investment cost was estimated for the storage system, demonstrating a real possible economic benefit in using these types of materials and heat exchange geometries, with the results varying, according to possible manufacturing prices, in a range from 25 to 40 EUR/kWh.

Steam reforming (SR) of natural gas is the most widespread process to produce hydrogen. This paper presents a comprehensive simulation of an industrial plant for hydrogen production for the internal use in a refinery industrial complex based on the SR of different feedstocks. The reference plant is a 42,000 Nm3/h hydrogen production unit located in the South of Italy in the Refinery of Milazzo, Sicily. Hydrogen is produced from light gaseous hydrocarbons and purified by means of pressure swing adsorption technology. In the present work, a process simulation has been built on scientific basis and validated against field data at different feedstocks and operating conditions. The model correctly predicts the effect of relevant process parameters such as reformer feed pressure and temperature, steam to carbon ratio and plant load. In addition, the paper proposes the design of an industrial-scale rapid vacuum pressure swing adsorption (RVPSA) unit which was designed and simulated to capture carbon dioxide from the flue gas exiting the steam reformer. The RVPSA unit was integrated in the current plant enabling the concentration of CO2 with a purity of 96.64%, an overall recovery of 90.84% and a specific energy consumption of 628.93 kJ/kgCO2, thus meeting the requirements for transportation and geological storage. An energetic efficiency calculation was introduced to quantify the effectiveness of the hydrogen conversion process and to predict the effect of CO2 capture and some process parameters to the overall H2 production efficiency.

Gasification is one of the most effective and studied methods for producing energy and fuels from biomass as different biomass feedstock can be handled, with the generation of syngas consisting of H2, CO, and CH4, which can be used for several applications. In this study, the gasification of hazelnut shells (biomass) within a circulating bubbling fluidized bed gasifier was analyzed for the first time through a quasi-equilibrium approach developed in the Aspen Plus environment and used to validate and improve an existing bubbling fluidized bed gasifier model. The gasification unit was integrated with a water-gas shift (WGS) reactor to increase the hydrogen content in the outlet stream and with a pressure swing adsorption (PSA) unit for hydrogen separation. The amount of dry H2 obtained out of the gasifier was 31.3 mol%, and this value increased to 47.5 mol% after the WGS reaction. The simulation results were compared and validated against experimental data reported in the literature. The process model was then modified by replacing the PSA unit with a palladium membrane separation module. The final results of the present work allowed comparison of the effects of the two conditioning systems, PSA and palladium membrane, indicating a comparative increase in the hydrogen recovery ratio of 28.9% with the palladium membrane relative to the PSA configuration.

Despite the emergency of water scarcity, the man's choices have always been directed towards the mismanagement of this vital resource; drinking water is far from being a right for everyone and is rather scarce and poorly distributed in many areas of the world. The aim of this work is to set up a water cost evaluation methodology based on the energetic equivalence among all the possible treatment strategies, water sources and water end-uses. An economic incentive is proposed on the basis of the thermodynamic and process analysis of a Wastewater Treatment & Reuse (WWTR) Plant. The analysis extends our previous approach to the whole panorama of the water-cycle related technologies. The energy use intensity of different (in-series) process of a water reuse project has been addressed: from the COD and nutrient removal, to the energy harvesting and to the separation of dissolved ions. The incentive is able to reward the processes having the goal of low energy consumption and low carbon emissions. The methodology has been applied to WWTR projects at different scales. The results showed that it is possible to obtain an acceptable Return of Investment (ROI), even for a low plant productivity (around 200 m3/day). Moreover, based on the profitability of the WWTR Project, the calculation of the “true value” of the “water source” has been presented. An acceptable price of waster (as a commodity) is evaluated for both wastewater and seawater by varying the potentiality of the water reclamation plant. This calculation could be implemented to evaluate the economic benefit of public investment as well as to reduce the use of water from non-renewable sources.

Water is fundamental for the quality of both ecosystems and society, and plays a key role for energy and food production, a prerequisite for the sustainable development [...]

Thermal energy storage technology with Phase Change Materials (PCM) is an attractive option to optimise energy resources and to recover and promote excess heat. The phase change behaviour of PCM requires advanced research to understand and better control the thermal energy storage using PCM, which is a crucial step to develop a powerful latent storage system. This paper aims to analyse the multiphysics phenomena of three regenerator configurations, horizontal case and two injection direction of Heat Transfer Fluid (HTF): top and bottom in vertical case. The study is done for the charge and discharge cycles of the solid-solid and solid-liquid phase transitions of PCM. First, the temperature dependence of the thermal and physical properties of paraffin as PCM is characterised. Second, an experimental study of an annular latent storage system was carried out. Also, an experimental mesh method was introduced to compare the energy behaviour of the three cases. Third, a numerical analysis of the experimental storage unit with low thermal diffusion is performed. The experimental results are confronted with the numerical results obtained with ANSYS Fluent and COMSOL Multiphysics commercial software. Last, the three configurations are compared to a reference case without gravitational field. The results show that specific mechanisms control the thermal and energetic behaviour of the regenerator. Furthermore, several parameters, such as storage density, distribution of energy storage rate in the different regenerator components (PCM, HTF, and heat exchanger), were analysed. Altogether, the results supply important information to understand the dynamics of passive storage systems.

Hydrodynamic cavitation (HC) has been extensively studied for the Advanced Oxidation of organic compounds in wastewaters since it physically produces an oxidative environment at ambient conditions. This process is simple and economical since it can be realized through a properly designed restriction in a pipeline, even in retrofit solutions. Several experimental works individuated similar values of the optimal operating conditions, especially with regard to the inlet pressure. Up to now, the available modeling works rely on a single-bubble dynamics (SBD) approach and do not consider the actual process configuration and pollutant transport in proximity to the oxidizing environment. This work describes different experimental results (from this research group and others) and applies a novel mathematical model based on a transport-phenomena approach, able to directly simulate the effect of HC on the pollutant degradation. The novel proposed model is able to reproduce well a large number of experimental data obtained in different conditions, with different apparatus and different molecules, and allows to interconnect both SBD, fluid-dynamics, and physio-chemical variables in order to deeply study the interaction between the transport of pollutants and the reactive environment. This paper includes collection and discussion of several experimental results with the related main process parameters, description of the novel model and validation against the cited experimental results (to explain the effect of the operating pressure), sensitivity analysis, and the performance limit of the HC with the proposed modeling approach.

&lsquo, Hydrogen as the energy carrier of the future&rsquo, has been a topic discussed for decades and is today the subject of a new revival, especially driven by the investments in renewable electricity and the technological efforts done by high-developed industrial powers, such as Northern Europe and Japan. Although hydrogen production from renewable resources is still limited to small scale, local solutions, and R&amp, D projects, steam reforming (SR) of natural gas at industrial scale is the cheapest and most used technology and generates around 8 kg CO2 per kg H2. This paper is focused on the process optimization and decarbonization of H2 production from fossil fuels to promote more efficient approaches based on membrane separation. In this work, two emerging configurations have been compared from the numerical point of view: the membrane reactor (MR) and the reformer and membrane module (RMM), proposed and tested by this research group. The rate of hydrogen production by SR has been calculated according to other literature works, a one-dimensional model has been developed for mass, heat, and momentum balances. For the membrane modules, the rate of hydrogen permeation has been estimated according to mass transfer correlation previously reported by this research group and based on previous experimental tests carried on in the first RMM Pilot Plant. The methane conversion, carbon dioxide yield, temperature, and pressure profile are compared for each configuration: SR, MR, and RMM. By decoupling the reaction and separation section, such as in the RMM, the overall methane conversion can be increased of about 30% improving the efficiency of the system.

Chemical storage systems are a promising innovative route to overcome the issue of the solar irradiation storage, resulting as cost effective and with high energy density. A main problem with these kinds of materials is to design a synthesis method for preparing stable reactive structures, presenting at the same time a high volumetric charging/discharging enthalpy. At this purpose, a size controlled spinel was produced, characterized and investigated regarding its thermophysical and kinetics properties. The obtained powder presents an average diameter between 100 and 200 µm and an energy density of 133 J/g and an experimental test was carried out to verify the spinel morphology stability under thermal cycles. The specific heat is similar to other structured chemical storage system and makes the spinel feasible to be used also as sensible accumulation medium. Despite the relatively high particles size, and the expected small exposed reactive area, the charging, and especially discharging reaction rates resulted particularly favourable and comparable with the reported behaviour of micrometric powders. The particularly simple preparation method plus the cost effectiveness of the precursors leads to a quite convenient expected cost for the storage material, absolutely similar to commercially available accumulation systems.

The chapter is focused on the main strategies for the modeling of sustainable processes. An overview of the fundamental elements that characterize the development of the basic design of a process is presented, assessing case studies for the following topics: (i) thermodynamics modeling for process analysis, with the definition of the rules of thumb for the selection of a proper thermodynamics model for specific cases; (ii) process analysis and simulation, with the dynamic modeling of an absorption column; (iii) exergetic analysis and its effect on the techno-economic analysis of separation processes. The scope of the chapter is to give an overview of the main criteria to be followed for modeling, having in mind the need to objectively quantify the actual impacts of the process on resource consumption.

This chapter describes a new gastro intestinal (GI) model, based on membrane bioreactors, able to evaluate the bioavailability of drugs, also in presence of food. The model includes the physiology of five compartments: stomach, duodenum, jejunum, colon, and blood. All the compartments are interconnected with valves that control the flux in input and output from the compartments (discontinuous running mode). The molecule passage in the blood occurs though a transmembrane flux. The simulation of GI absorption starts with the input of the bolus in the stomach. The emptying of the stomach is controlled by enzymatic reactions in the duodenum, therefore controlling this stage without any external function or parameters, but only using the physiological process. The parameters used work for the optimal condition of the reactions (pH in optimal range, presence of bile salts, etc.). Paracetamol and ketoprofen are the drugs implemented for model validation. The data obtained from the model are comparable with in vivo results from literature. The reference parameters are maximum concentration, time to enter and exit from therapeutic range, and time to reach the maximum concentration. The tests “with food” include a nutrient concentration to simulate a meal with 150 g of bread and 20 g of butter. The maximum concentration in blood for the test 1 is 0.153 mmol L− 1 for the paracetamol, while for ketoprofen it is 0.0243 mmol L− 1. The times to reach the maximum concentration for both the ketoprofen and paracetamol are about 55 min. In the presence of the meal, drugs show different pharmacokinetics. The maximum concentration for ketoprofen is 0.0135 mmol L− 1. The time to reach the maximum concentration is 3 h and 35 min.

The desalination through humidification-dehumidification (HDH) presents still a high energy-footprint but shows many unique attributes that pushed a recent revival of R&D for decentralized production of water. In this paper, a novel process scheme consisting of a multiple extraction humidification-dehumidification with vapour adsorption (HDHA) and brine recirculation is analysed. It works with bottom brine temperatures below the coldest heat source and direct recirculation. With respect to the common classification, the process can be considered a closed-air closed-water (CACW) HDH. The study of the degrees of freedom and the mathematical model for the sensitivity analysis are presented. Process simulation showed how to increase the performances above the GOR of 10 with multiple extractions. The basic design of a HDHA producing > 30 m3 day− 1 of distilled water, with higher performance (GOR of 7 and a RR of 50%) than the current state-of-the-art, is discussed. Furthermore, the paper reports the process scheme and the mathematical model of the adsorption unit integrated with the HDH, the breakthrough curves and the mass of sorbent needed to carry the novel process. The considerations here presented highlight the key benefits of the new process and bode well for its technological development.

In this research, micellar enhanced ultrafiltration (MEUF) is tested as a seawater pre-treatment before entering RO. The experimental tests were performed by means of monotubular ceramic membranes of 210 kDa and 1 kDa. Boron is removed from the water flow using sodium dodecyl sulphate as a surfactant. The synthetic solutions contain 5 mg/L of boron and SDS concentrations are equal to 1.15 g/L and 2.88 g/L, under and above the critical micellar concentration, respectively. Experimental data showed that MUEF is efficient in removing boron, with best performances obtained at low pressure, with a low or null surfactant concentration for 1 kDa membrane and a high surfactant concentration for 210 kDa membrane. Moreover, experimental results have been used to perform a preliminary process analysis for a hypothetic sea-water desalination plant, with MEUF as a pretreatment for the RO section. The results showed that the MEUF guarantees a boron concentration after RO below the allowed threshold, by using a single step osmosis; moreover, in this way it was possible to reduce the energy consumption thus resulting in an appreciable reduction of carbon footprint as well as of the unit cost of water.

DME production represents a possible route of CO 2 valorisation in the decarbonization pathway. This paper provides an insight into the basic design and process analysis of a DME production plant by implementing Membrane Reactors to convert CO 2 at acceptable values. The paper provides the process analysis of the overall plant architecture related to an innovative DME production process configuration, called Double Recycling Loop DME (DRL-DME), enables the utilization of a pure CO 2 stream as sweeping gas in the permeation zone (PZ) and a double recycling loop to reintroduces the un-reacted syngas and the outlet stream from the PZ. The mathematical model of the entire plant is presented and implemented to study the effect of the process parameters on the performances. This paper brings a step forward by determining the possible configuration and the performance of a whole industrial plant, able to realize the DME synthesis from CO 2 -rich streams in membrane reactor with recirculation. The whole process includes the utilization of a pure CO 2 external feed, the steam production and all the necessary separation units. By fixing the set point of the process control variables, the recirculation streams are calculated though a mathematical algorithm founded on previous literature results. Through the mathematical model it is possible to estimate the CO 2 conversion and DME yield as well as the main features of the plant, by varying some important process parameters (e.g. feedstock composition, reactor pressure, H 2 /COx).

Cold storage is a valid solution for the energy peak reduction in the air conditioning field, which strongly affects the energy consumption in the civil sector. An innovative storage device, called ColdPeak , has been already tested in a recently published work, demonstrating unparalleled properties in terms of charging/discharging storage power. Now, the unit is analyzed from the environmental point of view by means of a LCA (Life Cycle Assessment) methodology: the air conditioning system integrating the ColdPeak unit has been compared with a conventional system from the environmental point of view, assuming the same potentiality of cold energy and including a sensitive analysis on the energy saving potential of the innovative device (5–25% of the energy required by the conventional system). In the sensitivity analysis, the energy saving is counter-balanced by the energy load required for the manufacturing and installation of an additional component in the air conditioning system (the ColdPeak device itself). The environmental footprint that considers the material and the energy to fabricate the ColdPeak is very low if compared with the amount of energy saved thanks to its application. As a matter of fact, the LCA study reports that the integration of the cold storage unit allows a significant reduction of environmental footprint in terms of Global Warming Potential (−17%), Acidification Potential (−15.5%), Eutrophication Potential (−18%), Eco-toxicity (−16%), Human Health (−18%) and Fossil Depletion (−18%). The paper also reports the temporal trend of the environmental footprint that shows a pay-back period for the construction of the innovative integrated system of less than one year for all the investigated categories.

Closed-loop insulin delivery system, also known as artificial pancreas (AP), provides the blood glucose control in diabetic patients, enabling the automatic blood-sugar management and reducing the risks and improving the lives of people with diabetes. A new three-compartmental model of glucose-insulin interaction for AP is presented and tested in this paper. The glucose and insulin "spaces" are split into a plasma compartment and interstitial fluids compartment, respectively. The model includes an additional subcutaneous compartment and provides three explicit delays and three parameters influencing the regulatory system and correlating with the physiopathology of the patients. Two delays are related with hepatic glucose production and insulin secretion; the third delay represents the lag time in the absorption of exogenous insulin in subcutaneous tissue. The parameters regulate the system dynamics acting on the glucose utilization and the insulin secretion. The clinical data (including information on food ingestion and exogenous insulin injection) from five case studies of Type 1 diabetics are presented and used to validate the mathematical model. After training the parameters for each case study, the model well simulates the glucose level during a 4-day test. The estimated values are physiologically meaningful and provide a further insight on the subject's dysfunctions and on the state of the disease. The results have been also compared with a parallel simulation carried out by implementing a previous two-compartmental model. The proposed algorithm produces a lower sum of the squared error between the simulated and the measured glucose concentrations over time.

The integration of a microporous zeolite membrane, highly selective to steam water in a one-step DME synthesis reactor, is modeled and assessed. The membrane reactor performance and the comparison with a conventional reactor, are studied mainly for a CO2-rich feedstock, i.e. derived from a biogas-derived syngas. The continuous removal of water from the reaction environment reduces the inhibition effect of H2O on the CO2 hydrogenation and methanol dehydration reactions, thus allowing the achievement of high conversions, DME yield and selectivity even at large CO2 composition in the inlet feedstock. If a CO2/CO ratio equal to 3 is imposed in the inlet stream, the DME yield reaches a value of 0.75 vs. 0.57 in a conventional reactor operating at the same conditions, the XCOx and XCO2 are 0.75 and 0.69, with an improvement of 15.4% and 30.2%, and the DME selectivity is close to 1. The membrane reactor behavior is assessed by a one-dimensional, non-isothermal model. Fixing industrial scale parameters, the effect of the main operating conditions as temperature and pressure in the reactor environment, the Gas Hourly Space Velocity (GHSV), the feedstock composition in terms of CO2/CO and H2/COx ratios, the pressure and flow rate downstream to the selective membrane are analyzed and discussed. The simulations confirm the improvement of the reactor performance, within large ranges of operating conditions, derived from the integration of the selective membrane. On this basis, membrane reactor for one-step DME synthesis process can be included in the “CO2 valorization” framework since the greenhouse gas CO2 can be used as a reactant in an industrial process and thus converted into a useful and marketable product.

This paper presents the modeling theory and results of an innovative thermal energy storage (TES) facility, ideated, realized, and tested by ENEA (Italy). This prototype enabled the thermocline storage with molten salts in a novel geometry ideated for small-medium scale decentralized solutions, which includes two vertical channels to force the circulation through two heat exchangers, respectively, and realized for charging and discharging phases (in a single tank). A thermophysical model was built and tested properly for this particular geometry in order to analyze the temperature distribution along the radius. The numerical results well reproduced the experimental values. Furthermore, the analytical solution provided a short-cut methodology able to evaluate the thermocline distribution (along the vertical axis) depending on both the time and the radius values. Hence, the influence of the radial position (r) on the thermocline degradation was studied finding that, at the edges (r → 1), the thermocline remains unchanged for longer (around ten times more) than at the center of the tank (r → 0). The obtained numerical modeling and the analytical correlation can be useful for the process analysis to scale-up the thermal storage system and to evaluate the system reliability for industrial plants.

Gasification is one of the most effective and studied methods for producing energy and fuels from biomass as different biomass feedstock can be handled, with the generation of syngas consisting of H2, CO, and CH4, which can be used for several applications. In this study, the gasification of hazelnut shells (biomass) within a circulating bubbling fluidized bed gasifier was analyzed for the first time through a quasi-equilibrium approach developed in the Aspen Plus environment and used to validate and improve an existing bubbling fluidized bed gasifier model. The gasification unit was integrated with a water-gas shift (WGS) reactor to increase the hydrogen content in the outlet stream and with a pressure swing adsorption (PSA) unit for hydrogen separation. The amount of dry H2 obtained out of the gasifier was 31.3 mol%, and this value increased to 47.5 mol% after the WGS reaction. The simulation results were compared and validated against experimental data reported in the literature. The process model was then modified by replacing the PSA unit with a palladium membrane separation module. The final results of the present work allowed comparison of the effects of the two conditioning systems, PSA and palladium membrane, indicating a comparative increase in the hydrogen recovery ratio of 28.9% with the palladium membrane relative to the PSA configuration.

The biological treatment of the aqueous residue produced during poplar wood pyrolysis was investigated. The biological treatment experiments were carried out at two different pH conditions (controlled at 7, uncontrolled) in batch mode at three different temperatures (15 &deg, C, 25 &deg, C and 30 &deg, C) and initial total organic carbon of the water ranging from 800 mg/L to 2800 mg/L. Results show that a substantial removal of organic carbon could be achieved in aerobic conditions after biomass acclimation. After 72 h of treatment, total organic carbon (TOC) removal mean values of 49.47% and 53.03% were observed at 30 &deg, C for solution at 1400 and 2000 mg/L initial TOC, respectively. In the case of 1400 mg/L, a further mineralization (61.80%) was achieved during 144 h of treatment, by using a two-step process. A kinetic study of the process was also made, showing that organics mineralization followed a first-order kinetic model.

The reuse of wastewater is a key factor in a closed water cycle approach, in which wastewater is treated and then reused. This approach is both mandatory for the development of dry areas and necessary for the sustainability of industrialized countries in terms of environmental impacts and resource preservation. Although there are some virtuous examples of water reuse projects in the world, there is still much to be done, especially in terms of incentives and economic viability. Aim of the present paper is to give thermodynamic and engineering elements in order to develop an economic incentive to promote wastewater reuse and to adopt the closed water cycle approach. At this scope a techno-economic analysis of the civil wastewater depuration and reverse osmosis treatment of the secondary effluent is presented, by using the typical approach of the chemical engineering. The cost of the treated water in relation to the fundamental parameters of the plant is calculated together with an “energy based” incentive, evaluated through the efficiency of the state-of-the-art desalination process. This last can make a reuse project economically feasible on the basis of rigorous thermodynamic considerations. These latter give a universal character to the incentive calculation and also reward the process optimization towards the goal of lowering the carbon emissions. The validity of the proposed method is evaluated through the analysis of three wastewater treatment and reuse projects at different scale. The results show how it is possible to obtain a positive Earnings Before Interests and Taxes (EBIT) for plant productivity above the 200 m3/day, by including the proposed incentive in the Business Plan of the integrated plant of Water Treatment and Reuse.

An innovative solution to store cold energy for civil application based on phase change materials (PCM) is presented and evaluated. The storage tank is thought to be installed in a traditional chiller-fan coil system to shave the electricity peak loads required by the users, thus allowing a better management of the electricity grids (by avoiding the summer peaks for air conditioning) and a significant energy saving thanks to the improvement of the chiller Coefficient of Performance (COP). A 5 kWh prototype has been tested to prove the technological feasibility and has been simulated by a physical-mathematical model based on the energy balance and heat exchanging equations. The model, once validated against experimental data, has been implemented to assess the technology behavior changing operating parameters as the filling ratio, the initial temperature of the PCM and the charging power. The optimization of the heat exchanging configuration can lead to a minimum loading time of 54 min for the 5 kWh storage tank (charging power of 5.7 kW). Globally, the mathematical simulations confirmed the capability of the system to operate at high charging/discharging power, thus making it optimal for the integration in a chiller-fan coil system with the “peak shaving” logic.

Waste-to-Chemicals production represents a sustainable pathway considering the new Circular Economy approach and the environmental problems related to waste disposal management. This paper concerns about the LDPE production starting from a nonrecyclable plastic waste feedstock, providing a solution to both plastic demand and plastic waste disposal. The proposed process combines different technologies starting from a high temperature gasification of waste, which leads to a no tar syngas production. The present paper provides a feasibility analysis in order to reach an interesting product yield and an innovative process configuration, reporting the overall plant block scheme and the Process Flow Diagram. The heat and material balances of the entire production chain, including the steam production, the byproducts separations and the plant furnace units, were developed via the simulation software Aspen Plus V8.0. The paper shows each simulator flowsheet of some significant plant sections, reporting all the necessary equipment and thermal recoveries and the properties of each plant unit outlet stream. Last but not at least a feedstock analysis is developed by comparing the mixed plastic feedstock to the RDF one, showing the resulting data and considerations.

Geothermal brines can be a resource of energy, freshwater and minerals. Even when rejected after their exploitation to produce energy in a power plant, the brines can be a source of freshwater and minerals, and can have a residual enthalpy that can be recovered to produce additional power. The different reuse scenarios of these wasted brines depend on the composition and temperature at which they must be reinjected into the wells. On this basis, geothermal energy production is a perfect case study to investigate the water&ndash, energy nexus and to optimize the integrated energy- and water-production processes. In this paper, two case studies of brine reuse for both energy and water production are presented with the related process analysis, basic design and technical&ndash, economic analysis. A methodology to evaluate the exergy efficiency of the processes is presented by analyzing minimum work of separation, the maximum achievable work and the additional primary energy required for integrated production. The novel approach to estimate the process efficiency for integrated geothermal energy and desalination plants is applied to the case studies and discussed in light of literature results.

Hydrogen is a promising energy carrier, and is exploitable to extract energy from fossil fuels, biomasses, and intermittent renewable energy sources and its generation from fossil fuels, with CO2 separation at the source being one of the most promising pathways for fossil fuels&rsquo, utilization. This work focuses on a particular configuration called the Reformer and Membrane Module (RMM), which alternates between stages of Steam Reforming (SR) reactions with H2 separation stages to overcome the thermodynamic limit of the conventional SR. The configuration has numerous advantages with respect to the more widely studied and tested membrane reactors, and has been tested during a pilot-scale research project. Although numerous modelling works appeared in the literature, the design features of the material exchanger (in the so-called RMM architecture) of different geometrical configurations have not been developed, and the mass transfer correlations, capable of providing design tools useful for such membrane modules, are not available. The purpose of this work is therefore to apply a physical-mathematical model of the mass transfer, in three different geometries, considering both concentration polarization and membrane permeation, in order to: (i) simulate the cited experimental results, (ii) estimate the scaling-up correlations for the &ldquo, material exchange modules&rdquo, and (iii) identify the mass transfer limiting regime in relation to the gas mass flow rate.

This chapter focuses on the methanol and DME synthesis processes fed by a CO2-rich syngas feedstock derived from a biological process as fermentation or gasification of biomasses. The conversion of a CO2-rich stream allows the valorization of carbon dioxide, converting it into added high-value products such as methanol and dimethyl ether. However, a thermodynamics analysis highlights the strong negative effect that an inlet CO2 composition has on conversion reactions and the products yielded. The solution to supporting methanol/DME production processes with high contents of CO2 is to integrate a membrane that is selective to water and able to remove the generated steam. This approach avoids accumulation of water inside the reaction environment, thus overcoming the thermodynamic thresholds and supporting the methanol and DME generation reactions. The water selective membrane study leads to the conclusion that only the microporous zeolite are suitable to operate at production process conditions (200–300°C and 50–70 bar). Moreover, two different plant configurations are proposed: the integrated membrane reactor, where the membrane is directly installed in the synthesis catalytic reactor, and the staged membrane reactor, consisting of a series of reactor + water separation module units. In order to apply the membrane reactor technology in industrial methanol/DME processes, the selective membranes must ensure stable and durable performance in terms of water permeance (> 10− 7 mol s− 1 m− 2 Pa− 1) and H2O/H2 selectivity (> 10).