Specific Consumption Research Articles

Supercritical CO2 Extraction From Leptocarpha rivularis Stalks Using Box–Behnken Design

AbstractThe effect of temperature, pressure, and specific solvent consumption on extraction yield from Leptocarpha rivularis stalks was studied using a Box–Behnken design. The effect of pressure on extraction yield was the most important, followed by temperature and specific solvent consumption (p ≤ 0.05). The extraction yield correlated (p ≤ 0.05) positively with the CO2 density. A diffusion model adequately described the cumulative extraction curve with the highest yield at the selected extraction condition. The inhibition of linoleic acid oxidation and the inhibition of lipoxygenase enzyme were higher in the supercritical (SC) extract than in the hydroethanolic extract. SC extraction could be used to isolate compounds from L. rivularis stalks with functional value.

Yogurt as a fermented food for healthy and sustainable daily consumption. Recommendations to the population

Yogurt has been valued very positively for centuries, but the concern for food sustainability and the fact that it is a food of animal origin has raised doubts about the consumption that may be convenient. The objective of this work is to deepen the topic and establish recommendations for the population. From the nutritional point of view, yogurt is a valuable food, for its high content, quality and bioavailability of its nutrients, in a low energy content, its components together with probiotic microorganisms are provided in a matrix that helps achieve greater nutritional and health benefit. Regular consumption of yogurt has been linked to cardiovascular protection, against diabetes, excess weight, cancer, bone health. Thinking about environmental sustainability, yogurt production is not particularly dangerous, as the kg of CO2 eq (greenhouse gases) associated with their production are the lowest obtained compared to other animal foods and even lower than those associated with the production of some plant foods and the supply of nutrients per 1000 kcal, per 100 g, or per euro is one of the highest available. There is the possibility to further improve sustainability with improvements in animal feed, packaging, transport, etc. Considering this evidence, the daily consumption of yogurt / fermented milk should be included in the food guidelines, not only as one more milk option, but specifying a specific consumption such as a ration / day, this pattern can be useful from the nutritional point of view and for the improvement of public health.

Electric energy consumption (EEC) in groundwater-based drinking water supply systems: analysis and comparison of seven Italian case studies

ABSTRACT Drinking water and wastewater services depend on energy: electric energy consumption (EEC) of this sector amounts to 2–3% of global EEC. The attention of the scientific community and of water utilities about this topic is focused on energy optimization of wastewater treatment plants and pumping stages in drinking water supply systems (DWSSs). However, because of increasingly stringent regulations and because of more and more extended water-source pollution, the need for ‘unconventional’ drinking water treatment systems, which are very energy-intensive, will bring treatment to be a key factor in this scenario. Analyzing EEC in seven full-scale DWSSs, we wanted to control EEC in every single stage of the DWSS (withdrawal, drinking water treatment plant (DWTP) and distribution) and to identify opportunities for reducing energy consumption in DWSS, with a special focus on each drinking water treatment process. The most energy-intensive unconventional treatment turns out to be membrane filtration by reverse osmosis (for which specific consumption per cubic meter of pumped water is equal to 0.243 Wh/m3), whereas the most energy-intensive conventional treatment turns out to be air oxidation (specific EEC from 0.012 to 0.087 kWh/m3). The main strategies for energy conservation can be applied both in management and in the design phase.

Energy features of CO2-cycles during oxygen combustion of methanol

The PURPOSE of the work is to determine the mass-flow characteristics of working substances and energy indicators of an installation based on a CO2 cycle with a two-stage pressure increase (Allam cycle) during oxygen combustion of methanol.METHODS. A research methodology is presented in which the mass-flow characteristics of working substances are determined based on the reactions of combustion and synthesis of methanol and electrolysis of water. These reactions are basic for ensuring operational processes in the installation. The method is based on the molar ratios of substances participating in reactions under stoichiometric conditions. Using the thermodynamic parameters of the cycle being implemented and at a given installation power, the consumption of the working fluid, the share of carbon dioxide renewal in the cycle, the amount of methanol produced in the synthesis unit, the amount of fresh methanol, the amount of hydrogen produced in the water electrolysis unit and the amount of oxygen are determined, necessary to ensure fuel combustion processes. At the same time, the amount of commercial hydrogen is determined. Electricity consumption for own needs is determined using regulatory methods and data from equipment manufacturers.RESULTS. The article shows that with similar values of thermal efficiency of CO2 cycles based on oxygen combustion of methane and methanol, the amount of carbon dioxide removed from the cycle for disposal is 11% less. It has been shown that a CO2 cycle operating on methanol is capable of producing commercial hydrogen simultaneously with electricity generation. The specific electricity consumption for hydrogen production is 22% less than for its production without combination with the CO2 cycle.

A Biomass-based Carbon Negative Brayton-Rankine Coupled Cycle Employing MCFC, Gasification and Combustion Boiler

Biomass based plants with CO2 capture usually experience low efficiency, at the same time, have great potential of mitigating environmental damage due to climate change. In this work, unlike conventional power plants, a novel biomass-based carbon negative power plant has been conceived considering both biomass gasification and a biomass combustion boiler. CO2 capture and improved efficiency due to the unique integration of the plant components are the major expected outcome from the proposed plant model. The plant contains a steam cycle, an MCFC and an EFGT unit as the power producing blocks. A vital operating parameter i.e., biomass combustion boiler equivalence ratio () has been varied to witness the changes in performance of the plant. The net power generated by the plant seemed to be increasing with . The plant performs best when the plant is operated at a  value of 2.5. At this operating condition, the net power generated by the power plant found to be 13796 kW with 75.52 % efficiency and 0.3957 kg/kWh specific biomass consumption (SBC).

An overview of the constructions of conveyors for moving bulk materials, comparison and study of their parameters

The production of concrete mixes, along with their use in the production of building materials and structures, is one of the key processes in the construction industry during the construction, restoration and repair of buildings and structures. Because of this, the need to create modern concrete mixing plants that will meet the requirements of minimum energy consumption and maximum productivity of concrete mixture production is an urgent task. Not only the main operations, which include the dosing of the components of the mixture and their mixing, but also the maintenance operations, namely operations that ensure the timely movement of the components of the concrete mixture from warehouses to the main technological equipment, affect the set rhythm of the concrete mixture production. Conveyors of various types and designs are used to move bulk materials, such as crushed stone and sand. For the rational selection of such equipment in accordance with the characteristics of the cargo to be transported, knowledge of the types of conveyors, their structures and parameters, understanding of operation issues and methods of parameter calculation are required. In addition, it is worth paying attention to the following parameters: maximum cargo transportation productivity, low energy consumption per unit of moved products, low metal content of the structure. The work reviewed the most common designs of conveyors used to move bulk materials in concrete mixing plants, analyzed the disadvantages and advantages of conveyors, as well as technical parameters. As a result, the predominant directions for the use of belt and plate conveyors at construction enterprises were determined. The advantages of belt conveyors, which contribute to their widespread distribution, are high productivity, simplicity of design, reliability, quiet operation, low specific power consumption. When choosing a conveyor, it is recommended to choose the equipment with the highest productivity and the lowest power of the drive motors, however, the performance should be clearly related to other technological equipment.

A multi-node thermodynamic model on temperature-vacuum swing adsorption (TVSA) for carbon capture: Process design and performance analysis

The adsorption technology plays a significant role in the carbon capture domain for mitigating the CO2 emissions, whereas the heterogeneous character is presented in practical adsorption process. In this study, a multi-node thermodynamic model is established for temperature-vacuum swing adsorption (TVSA) considering the end non-uniform adsorption. It shows superior performance for the assessment of practical TVSA cycle compared with lumped model. Through the influence analysis of different operation parameters based on multi-node model, specific exergy consumption increases from 41.6 to 62.4 kJ/mol caused by simultaneous drop of heat consumption and lift of work consumption as feed pressure raises from 1.0 to 3.0 bar. Exergy efficiency ranges between 13.8 % and 15.0 % as CO2 concentration increases from 10 % to 20 %. However, those under ppm-level are below 0.86 %, presenting the higher exergy consumption but lower desorption capacity represented for direct air capture. The heat consumption of front half part of adsorption bed is 39.7 % higher than the latter one, proving the potential cascaded desorption of subzone heating is superior for reducing the energy consumption. Furthermore, exergy consumption is lifted due to enhancement of work consumption of vacuum pump as vacuum pressure reduces from 1.0 to 0.02 bar, resulting exergy efficiency drops from 19.6 % to 13.4 %.

Effects of plastic aging on biodegradation of polystyrene by Tenebrio molitor larvae: Insights into gut microbiome and bacterial metabolism

Plastics aging reduces resistance to microbial degradation. Plastivore Tenebrio molitor rapidly biodegrades polystyrene (PS, size: < 80 μm), but the effects of aging on PS biodegradation by T. molitor remain uncharacterized. This study examined PS biodegradation over 24 days following three pre-treatments: freezing with UV exposure (PS1), UV exposure (PS2), and freezing (PS3), compared to pristine PS (PSv) microplastic. The pretreatments deteriorated PS polymers, resulting in slightly higher specific PS consumption (602.8, 586.1, 566.7, and 563.9 mg PS·100 larvae−1·d−1, respectively) and mass reduction rates (49.6 %, 49.5 %, 49.2 %, and 48.7 %, respectively) in PS1, PS2, and PS3 compared to PSv. Improved biodegradation correlated with reduced molecular weights and the formation of oxidized functional groups. Larvae fed more aged PS exhibited greater gut microbial diversity, with microbial community and metabolic pathways shaped by PS aging, as supported by co-occurrence network analysis. These findings indicated that the aging treatments enhanced PS biodegradation by only limited extent but impacted greater on gut microbiome and bacterial metabolic genes, indicating that the T. molitor host have highly predominant capability to digest PS plastics and alters gut microbiome to adapt the PS polymers fed to them.

Anoxic Manganese Bioleaching – Investigation of Scale-up Parameters in a Stirred Bioreactor

Presently huge operation costs arising from aeration and high electron donor requirements accompanied by low metal recovery rates are some impediments to the large-scale application of bioleaching for low-grade ores. The current study investigates key parameters for scaling up anoxic bioleaching, which overcomes some of the above shortcomings, on polymetallic manganese nodules using soil-based manganese-reducing bacterial consortia in a stirred bioreactor. Operating conditions such as carbon source concentration and pulp density were optimized. Parameters like pH, oxidation–reduction potential (ORP), and microbial growth were monitored in the bioreactor in both stirred and non-stirred conditions. The Mn(IV) reduction and dissolution in the bioreactor was 27 (±2.8)% over 30 days, which significantly enhanced to 43 (±1.5)% and 42 (±0.35)% in the presence of humic acid and anthraquinone sulfonic acid, respectively, in 15 days. A maximum dissolution of 21 (±4.1)% Cu, 10 (±3.0)% Ni, 18 (±4.7)% Co and 7 (±3.9)% Fe were also obtained with 100 µM humic acid from the agitated bioreactor in 15 days. The corresponding specific glucose consumption rate per unit mass of ore was found to be 27 mg g−1 day−1, which is 10 times lower than the rates reported previously for aerobic bioleaching methods. The investigation shows that mild agitation can significantly improve the anoxic bioleaching, especially with added electron shuttles, to enable better ore-bacteria interaction and prevent ore compaction during scale-up. The pH and ORP of the system point toward a reductive dissolution of Mn by the organisms.

Air conversion of pyrolysis products of hydrocarbon raw materials into synthesis gas (H2+CO) for the production of electrical energy using solid oxide fuel cells

The article discusses the technology of combined production of electrical and thermal energy using preliminary air conversion of the pyrolysis liquid of automobile tires into synthesis gas, with its subsequent supply to the battery of an electrochemical generator. The electrical power of the installation is 100 kW, the network heater is 126 kW. The main energy characteristics of the installation were determined using the methods of physicochemical modeling and compilation of energy balances. It has been shown that the specific consumption of pyrolysis liquid for the production of electrical energy is 108 g/kW∙h (169 g r.f./(kW∙h)), and the heat consumption is 30 kg/GJ (196 kg r.f./Gcal). The specific consumption of natural and conventional fuels is compared with the specific fuel consumption at power plants operating on hydrocarbon natural fuels. They are slightly inferior to them, with the exception of the specific electricity generation from external heat consumption. Fuel utilization rate 46.4%. Recommendations are given for the use of pyrolysis liquid to generate electrical and thermal energy using a high-temperature fuel cell based on SOFC.

Modelling and optimization of shea butter biodiesel engine performance evaluation using response surface methodology

In this study, the performance and emission parameters of compression ignition (CI) diesel engine powered by shea butter biodiesel blends with diesel via clay doped ionic liquid catalyst (CD-IL) were modelled, optimized and predicted using Response surface methodology (RSM) technique. Using the (American Society for Testing Materials) ASTM D 6751 criteria, the produced biodiesel's quality was successfully evaluated. The biodiesel blends (B0, B50, B100), load (100, 200, 300)kg and speeds (1400, 1800, 2200) rpm were considered as the factors while Brake thermal efficiency, Brake specific consumption, Brake power, Nitrogen oxide and carbon monoxide emission were considered as the responses of the shea butter biodiesel engine. Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Brunaeuer Emmet and Teller (BET) were used to analyze the catalyst before and after treatment to ascertain their suitability for the process. The capability of the models was evaluated using the correlation coefficient (R2) and mean square error (MSE). The second-order polynomial model is shown in the Analysis of Variance (ANOVA) with an (R2 -0.9948, Adjusted R2–0.9880, Predicted R2–0.9163) for brake thermal efficiency, (R2 -0.9908, Adjusted R2–0.9790, Predicted R2–0.8529) for brake specific consumption,(R2 -0.9988, Adjusted R2–0.9972, Predicted R2–0.9807) for brake power, (R2 -0.9995, Adjusted R2–0.9988, Predicted R2–0.9917) for Carbon monoxide emission and (R2 -0.9979, Adjusted R2–0.9951, Predicted R2–0.9659) Nitrogen dioxide emission demonstrating the model's acceptance. The optimal condition for shea butter biodiesel engine performance of brake thermal efficiency (16.3%), brake specific consumption(0.83),brake power (1.5), Carbon monoxide emission (175 ppm) and Nitrogen oxide (150 ppm) was obtained at a biodiesel blend (B50), load of 300 kg and speed of 2200 rpm. The 3D model graphs showed the process parameters impacted on the response significantly with better combustion, cleaner air.fuel ration blend, lesser friction loss and air consumption. Hence the proposed RSM modelling tool for shea butter biodiesel engine performance prediction had the best performance at (B50) (50% biodiesel and 50% diesel).

The influence of exercise and BMI on food choices during pregnancy

BackgroundExercise is linked to health-conscious behaviors, such as healthy eating, through psychophysiological pathways that include improvements in executive functioning. The influence of exercise while pregnant on healthy eating is currently unknown. PurposeTo determine if there are differences in food choices of women who exercised (EX) or not (CON) during pregnancy, and if this differed by pre-pregnancy body mass index (BMI; normal weight, NW; overweight/obese, OWOB). MethodsThis study was a secondary analysis to examine the food frequency questionnaires (FFQs) of pregnant women randomized to 150 min/wk of EX (n = 72) or CON (n = 16). Maternal descriptors and pre-pregnancy BMI were collected at enrollment (≤16 weeks gestation). At enrollment and at 36 weeks gestation, women reported the frequency of specific food consumption across a range of food groups based on a Likert-scale ranging from 1-rarely or never eat the food to 5- eat the food more than once/day. ResultsOWOB EX increased consumption of nutrient-dense foods from enrollment to 36 weeks pregnancy and these results were not seen in OWOB CON and NW CON groups. Since FFQ is self-reported and captures a broad scope of habitual diet, it is important for future research in this area. ConclusionOverall, data in our study suggests that OWOB women who start exercising during pregnancy also improve their diet. Thus, future research should investigate how exercise may influence changes in nutrient intake during pregnancy.

Associations of maternal lifestyle factors with inadequate pregnancy weight gain: findings from the baseline data of the LIMIT prospective cohort study.

Gestational Weight Gain (GWG) impacts maternal and fetal health; deviations from optimal ranges pose health risks. Maternal lifestyle before and during pregnancy strongly influences GWG. This study explores factors linked to inadequate GWG, focusing on Mediterranean Diet (MD) adherence and specific food consumption. 178 pregnant women were enrolled at Fondazione IRCCS Policlinico San Matteo (Pavia) during pre-hospital care before birth meeting inclusion/exclusion criteria. Sociodemographic data, pre-pregnancy BMI, GWG, MD adherence, physical activity (PA) levels, and smoking habits were retrospectively collected. Validated questionnaires adapted for the target group, assessed MD adherence and PA level. Participants were classified into adequate (AGWG) and inadequate GWG groups following IOM guidelines. Among 200 pregnant women (aged 30-36), 37.1% experienced low GWG and 24.1% excessive GWG. Our study revealed a significant association between inadequate GWG and educational level (P = 0.011); pre-pregnancy BMI (P = 0.005); MD adherence (P = 0.008), and daily average consumption of vegetables (P < 0.001). Our results also showed that a lower risk of EGWG vs. AGWG was associated with daily average consumption of vegetables (RRR = 0.279, P = 0.004), while a higher risk of EGWG vs. AGWG was associated with high daily meat product consumption (> 1.5 portions/day) (RRR = 7.83, P = 0.03). These findings emphasize the importance of promoting lifestyle changes before and during pregnancy to tackle the increasing incidence of inadequate GWG and improve the health outcomes of both mother and child.

Does artificial ecosystem recharge make sense? based on the coupled water orbit research framework

By formulating an innovative Coupled Water Orbit Research Framework (CWORF) in cohesion with the modified Hypothesis Extraction Method (HEM), this study undertakes a comprehensive examination and assessment of the Autonomous Water Orbit (AWO) linkages within each sector. Building upon this foundation, the CWROF also integrates Structure Path Analysis (SPA) to scrutinize the critical paths of the AWO in each sector. Additionally, the framework quantifies specific water consumption at different layers of the production chain, enabling a more precise assessment of water consumption and inter-sectoral water usage linkages compared to existing studies. By applying this framework, existing water conservation policies can be refined, thereby achieving enhanced environmental sustainability. The study utilizes six Input-Output (IO) tables and water resource bulletins spanning from 2002 to 2020, as published by the China Bureau of Statistics. It is instrumental in dissecting the current interplay between water resource utilization and economic development. This research aims to analyze the structural nuances of water consumption and the dependency characteristics across diverse sectors within the production chain. It strategically identifies pivotal paths and sectors in the production chain where water consumption is most pronounced, and highlights critical chains contributing to water stress. The results indicate that sectors such as “Farming, Forestry, Animal Husbandry, Fishery, and Water Conservancy” exhibit high water consumption. Furthermore, light industries, represented by “Food and Tobacco” and “Textile Product” sectors, significantly impact indirect water usage across sectors. The study also reveals that the strength of the water feedback loop in the economic system diminishes as the number of layers increases, with the aforementioned sectors frequently appearing in transmission paths and serving as key interface nodes. This research underscores the critical interconnections between water usage and economic activities providing a foundational framework for refining water conservation policies and enhancing water allocation and management capabilities. The introduced CWORF extends beyond conventional methods, offering a more precise and nuanced approach to measuring inter-sectoral water utilization.

Paving the way for low-carbon hydrogen supply chain deployment by exploring the potential of renewable energies and multisectoral hydrogen demand: Case study of France

France has set ambitious targets for hydrogen production in its National Roadmap, aiming to install at least 6.5 GW of electrolyzer capacity and produce 700,000 tons of hydrogen annually by 2030. The country is focusing on producing renewable or low-carbon hydrogen primarily through electrolysis. However, it faces significant barriers in rapidly scaling up renewable energy infrastructure and may need to consider import strategies to address potential shortages. Addressing these challenges requires investigating whether the availability of renewable energy for the production of electrolytic hydrogen could become a limiting factor for hydrogen adoption and potentially act as a bottleneck in its market integration. The methodology merges forecasts from the public and private sectors to address both renewable and non-renewable electricity production and the energy needed for rising hydrogen demand. The approach developed involves estimating France’s renewable energy supply up to 2050 and determines how much of this energy can be allocated to hydrogen production to ensure it remains carbon-free and genuinely renewable. Unlike many existing roadmaps that take a more general approach, the innovative part of this study is developing a territorial perspective to conduct a detailed analysis of potential mismatches between hydrogen supply and demand.Three distinct sources of electricity are considered for the electrolyzers, which could be connected to the grid or directly to renewable power plants: low-carbon electricity from the French grid, renewable electricity from re-powered solar and wind farms, and renewable electricity from newly installed power plants. Total electricity demand is projected to rise from 475 TWh/y in 2020 to 754 TWh/y in 2050, with the share of renewable energy increasing from 19% in 2020 to 69% in 2050.The study evaluates the demand for hydrogen in two key sectors, industry, which is heavily dependent on hydrogen, and mobility, which currently has a more modest contribution. Hydrogen demand is expected to increase from nearly 310 ktons per day in 2025 to over 2650 ktons per day by 2050.Given an average specific consumption of 55 kWh of electricity per kg of hydrogen produced, the total electricity demand for electrolytic hydrogen production is projected to grow from 17 TWh/year in 2025 to 146 TWh/year in 2050.It can be concluded that allocating the entire anticipated production from re-powered solar and on-shore wind farms in the coming years will not be sufficient to meet the electricity demand required for electrolytic hydrogen production. To prevent renewable energy from becoming a bottleneck for hydrogen market integration and to avoid the need for hydrogen imports, it is crucial to allocate 5% to 10% of the projected renewable output from newly installed plants to address the increasing hydrogen demand. This result is key to creating an optimal design model for hydrogen supply chains.

Performance and environmental impact of ethanol-kerosene blends as sustainable aviation fuels in micro turbo-engines

The research experimentally examines the viability of ethanol (E) as a sustainable aviation fuel (SAF) when mixed with kerosene (Ke) – Jet A aviation fuel + 5% Aeroshell oil. Various blends of ethanol and kerosene (10%, 20%, and 30% vol. of ethanol added in kerosene) were subjected to testing in an aviation micro turbo-engine under different operational states: idle, cruise, and maximum power. During the tests, monitoring of engine parameters such as burning temperature, fuel consumption, and thrust force was conducted. The study also encompassed the calculation of crucial performance indicators like burning efficiency, thermal efficiency, and specific consumption for all fuel blends under maximum power conditions. Physical-chemical properties of the blends, encompassing density, viscosity, flash point, and calorific power, were determined. Furthermore, elemental analysis and FTIR were used for chemical composition determination. The research delved into analyzing the air requirements for stoichiometric combustion and computed resulting emissions of CO2 and H2O. Experimental assessments were performed on the Jet Cat P80® micro-turbo engine, covering aspects such as starting procedures, acceleration, deceleration, and emissions of pollutants (CO and SO2) during diverse engine operational phases. The outcomes reveal that the examined fuel blends exhibited stable engine performance across all tested conditions. This indicates that these blends hold promise as sustainable aviation fuels for micro turbo-engines, presenting benefits in terms of diminished pollution and a more ecologically sound raw material base for fuel production.

Electrocoagulation efficiency probed using electrochemical impedance spectroscopy

Electrocoagulation efficiency probed using electrochemical impedance spectroscopy

Photosynthetic distribution inside a cylindrical photobioreactor for Botryococcus braunii: A fed-batch culture application

In this study, the physiological responses and kinetic parameters of Botryococcus braunii were analyzed during a highly irradiated fed-batch culture in a cylindrical photobioreactor. This work includes a model of photon distribution throughout the bioreactor, coupled with an analysis of photosynthetic performance to simulate the level of photosaturation, photolimitation, or photoinhibition during cell growth culture. Under this simulation, the kinetic and physiological behavior was evaluated during four cycles of fed-batch culture. Physiological responses showed cellular photoacclimation to high irradiance conditions, increasing the Electron Transport Rate (ETR) values 2.5 times from cycle 1 to cycle 4, while photoprotection mechanisms such as quantum yield YII and non-photochemical quenching NPQ remained efficient. The total pigment content was low compared to other studies, and a gradual decrease in Chl a, Chl b, and carotenoids was evident between each fed-batch cycle (a 25 % reduction from cycle 1 to cycle 4). Kinetics showed a gradual increase in productivity, growth rates, and nutrient consumption between cycles. The maximum biomass concentration as dry weight (4.86 ± 0.26gL−1) was obtained in cycle 4, which also showed the highest values of productivity (0.45gL−1d−1), specific growth rate (0.134 d−1) and consumption rate (NO3, PO4). The results correlate the engineering approach to the physiological characteristics of the species, indicating that it is possible to establish an efficient fed-batch system for microalgae production.

Experimental investigation of hydrodynamics and suspension characteristics in a boiling stirred tank reactor with helical coils

The boiling stirred tank reactor (BSTR) is widely used in the chemical industry, while the relevant basic data of hydrodynamics and suspension characteristics for reactor design are quite limited. In this work, the hydrodynamics and suspension characteristics in a BSTR with helical coils (BSTR@HC) were studied using three types of impellers. Particle image velocimetry and visualization experiments reveal different flow fields and nucleation processes of three impellers. Suspension experiments show that superficial vapor velocity, solid loading, and particle size play an important role for just-suspension impeller speed Njsv and power consumption Pjsv, while cloud height is mainly determined by superficial vapor velocity. Among the three impellers, radial impeller shows the best suspension performance in BSTR@HC. Correlations of Njsv and Pjsv were developed with relative mean deviations of 2.7% and 4.6%, respectively. Furthermore, a model for the estimation of energy efficiency was developed by evaluate specific power consumption εjsv.

Thermal Desalination Through Forward Osmosis Coupled With CO2-Mixture Power Cycles for CSP Applications

This work, performed in the framework of the H2020 EU project “DESOLINATION”, analyses the coupling between CSP plants using transcritical power cycles with CO2-mixtures and an innovative thermal desalination technique based on Forward Osmosis. Calculations are presented for a large scale CSP plant with central tower receiver and direct storage with solar salts in Dubai, adopting the mixtures CO2+SO2 and CO2+C6F6 in the power cycles. The heat rejected from the cycle condenser is recovered directly by the FO plant, where the draw solute is heated up from 40 °C to 76 °C, to allow for the regeneration of the draw solution used in the forward osmosis membrane. The thermo-responsive polymer adopted is PAGB2000, already considered in literature as a promising option. Results show a very effective synergy between the electricity and the freshwater production: high yearly solar to electric efficiencies are possible (around 19%), with a low freshwater specific thermal consumption (around 100 kWhth/m3). The proposed desalination method is more effective than a conventional MED system (with + 50% of yearly freshwater produced), while a larger solar field (+ 28% in surface area) is necessary for a PV+RO plant to produce annually both the energy and freshwater produced by the CSP+FO plants.