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Records with Subject: Process Design
Showing records 1 to 25 of 350. [First] Page: 1 2 3 4 5 Last
Valorization of OFMSW Digestate-Derived Syngas toward Methanol, Hydrogen, or Electricity: Process Simulation and Carbon Footprint Calculation
Aristide Giuliano, Enrico Catizzone, Cesare Freda, Giacinto Cornacchia
July 2, 2020 (v1)
Keywords: bio-hydrogen, bio-methanol, digestate, gasification, low carbon processes, process simulation
This paper explores a possible waste-based economy transition strategy. Digestate from the organic fraction of municipal solid waste (OFMSW) is considered, as well as a low-added value product to be properly valorized. In this regard, air gasification may be used to produce syngas. In this work, the production of methanol, hydrogen, or electricity from digestate-derived syngas was assessed by ChemCAD process simulation software. The process scheme of methanol production comprises the following parts: water gas shift (WGS) with carbon capture and storage units (CCS), methanol synthesis, and methanol purification. In the case of hydrogen production, after WGS-CCS, hydrogen was purified from residual nitrogen by pressure swing absorption (PSA). Finally, for electricity production, the digestate-derived syngas was used as fuel in an internal combustion engine. The main objective of this work is to compare the proposed scenarios in terms of CO2 emission intensity and the effect of CO2 stora... [more]
Fabrication of Highly Filled Composites with an Innovative Miniaturized Spouted Bed
Hannah Sophia Rothberg, Swantje Pietsch, Gerold A. Schneider, Stefan Heinrich
July 2, 2020 (v1)
Keywords: highly filled composites, mechanical properties of composites, miniaturized spouted bed, particle coating, three-point bending test
In nature bio-composites such as nacre show remarkable mechanical properties due to their complex hierarchical structure and high-volume fraction of its hard component. These composites are highly interesting for structural applications in different branches of industries for mechanical engineering and process technology. The aim of this work was to provide a scalable method for the production of highly filled composites by mimicking the structure of bio-composites. Therefore, composites from iron oxide (Fe2O3) and SBC-polymer (styrene-butadiene block copolymer) were fabricated by using a miniaturized spouted bed with an innovative fluidization gap design. Small iron oxide particles (25−45 μm) were fluidized in the spouted bed and coated with a polymer solution via a bottom spray nozzle. Afterwards the coated granules were hot-pressed and the mechanical properties of the obtained composites were tested. By this method composites with a bending strength of up to 6 MPa were fabricated. A... [more]
Dyeing of Innovative Bicomponent Filament Fabrics (PET/PTT) by Disperse Dyestuffs: Characterization and Optimization Process
Marwa Souissi, Ramzi Khiari, Wafa Haddar, Mounir Zaag, Nizar Meksi, Hatem Dhaouadi
July 2, 2020 (v1)
Keywords: bicomponent filaments, disperse dyes, dyeing, polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT)
PET/PTT bicomponent filaments yarn is produced by two polymers: the polyethylene terephthalate (PET) and the polytrimethylene terephtalate (PTT) extruded side by side. This yarn is known for its high mechanical properties in particular elasticity and elastic recovery. However, differences between physical and chemical properties of the two components make the dyeing step of this yarn complicated. The aim of this work is the development of a dyeing process for bicomponent filaments without altering their physical and chemical properties. Different techniques such as SEM, FTIR, and differential scanning calorimetry (DSC) were used to characterize the studied yarn. For dyeing, three different disperse dyes CI Disperse Red 167.1, CI Disperse Yellow 211, and CI Disperse Red 60 with different energy classes were studied. The influence of dyeing conditions in particular dyeing temperature, pH of dye bath, dyeing time, and carrier concentration in the dye bath was evaluated. Responses analyzed... [more]
Design and Evaluation of the Lab-Scale Shell and Tube Heat Exchanger (STHE) for Poultry Litter to Energy Production
Xuejun Qian, Yulai Yang, Seong W. Lee
July 2, 2020 (v1)
Keywords: analysis, design, electricity, Energy, hot water, poultry litter, shell tube heat exchanger, space heating, temperature change, trailer temperature
Poultry litter is one type of biomass and waste generated from the farming process. This study performed a performance and process analysis of poultry litter to energy using the lab-scale shell and tube heat exchanger (STHE) system along with a Stirling engine and a swirling fluidized bed combustor (SFBC). The effects of tube shape, flow direction, and water flow rates on water and trailer temperature changes were investigated during the poultry litter co-combustion process. Energy flow analysis and emissions were also studied. Results showed that the water outlet temperature of 62.8 ° C in the twisted tube was higher than the straight tube case (58.3 ° C ) after 130 min of the co-combustion process. It was found that the counter-current direction had higher water temperature changes, higher logarithmic mean temperature difference (LMTD), and higher trailer temperature changes than the co-current direction. A water flow rate of 4.54 L/min showed adequate heat absorption... [more]
Technical Aspects and Energy Effects of Waste Heat Recovery from District Heating Boiler Slag
Mariusz Tańczuk, Maciej Masiukiewicz, Stanisław Anweiler, Robert Junga
June 23, 2020 (v1)
Keywords: coal slag, heat recovery, high temperature heat pump, thermodynamic analysis, waste energy
Coal continues to dominate in the structure of the heat production system in some European countries. Coal-fired boilers in district heating and power generation systems are accompanied by the formation of large quantities of slag and ash. Due to considerable high temperature, slag may be used as a source of waste energy. In this study, the technical possibilities of recovery slag’s physical enthalpy from grate-fired district heating boiler of 45 MW thermal capacity are analyzed. The aim of the work is to estimate the waste energy potential of the slag in analyzed boiler and proposition of the heat recovery system. The construction and design of the existing deslagging system was examined. Studies have shown that high water temperature accelerates system wear. Recovering heat from this system decreases the water temperature, which extends the trouble-free working time. The slag parameters were determined, including the temperature at the outlet of the boiler and the temperature after l... [more]
A Generalised Assessment of Working Fluids and Radial Turbines for Non-Recuperated Subcritical Organic Rankine Cycles
Martin T. White, Abdulnaser I. Sayma
June 23, 2020 (v1)
Keywords: computed-aided molecular design (CAMD), organic Rankine cycle (ORC), radial turbine design, small-scale, working-fluid selection
The aim of this paper is to conduct a generalised assessment of both optimal working fluids and radial turbine designs for small-scale organic Rankine cycle (ORC) systems across a range of heat-source temperatures. The former has been achieved by coupling a thermodynamic model of subcritical, non-recperated cycles with the Peng⁻Robinson equation of state, and optimising the working-fluid and cycle parameters for heat-source temperatures ranging between 80 ° C and 360 ° C . The critical temperature of the working fluid is found to be an important parameter governing working-fluid selection. Moreover, a linear correlation between heat-source temperature and the optimal critical temperature that achieves maximum power output has been found for heat-source temperatures below 300 ° C ( T cr = 0.830 T hi + 41.27 ). This correlation has been validated against cycle calculations completed for nine predefined working fluids using both the Peng⁻Robinson equation... [more]
Exergo-Ecological Assessment of Waste to Energy Plants Supported by Solar Energy
Barbara Mendecka, Lidia Lombardi, Paweł Gładysz, Wojciech Stanek
June 23, 2020 (v1)
Keywords: exergy analysis, solar energy, thermoecological cost, WtE plant
Hybridization of Waste to Energy (WtE) plants with solar facilities can take competing energy technologies and make them complementary. However, realizing the benefits of the solar integration requires careful consideration of its efficiency. To analyse such systems from the point of view of resource efficiency, the pure energy analysis is not sufficient since the quality of particular energy carriers is not evaluated. This work applies the exergo-ecological analysis using the concepts of thermoecological cost (TEC) and exergy cost for the performance evaluation of an integrated Solar-Waste to Energy plant scheme, where solar energy is used for steam superheating. Different plant layouts, considering several design steam parameters as well as different solar system configurations, in terms of area of heliostats and size of the thermal storage tank, were studied. The results for the solar integrated plant scheme were compared with the scenarios where superheating is performed fully by a... [more]
Techno-Economic Analysis of a 600 MW Oxy-Enrich Pulverized Coal-Fired Boiler
Ming Lei, Cen Sun, Chunbo Wang
June 23, 2020 (v1)
Keywords: oxy-enrich combustion, oxy-fuel combustion, PSA, technological economy
Oxy-fuel combustion is one of the most promising methods for CO₂ capture and storage (CCS) but the operating costs—mainly due to the need for oxygen production—usually lead to an obvious decrease in power generation efficiency. An “oxy-enrich combustion” process was proposed in this study to improve the efficiency of the oxy-fuel combustion process. The oxidizer for oxy-enrich combustion was composed of pure oxygen, air and recycled flue gas. Thus, the CO₂ concentration in the flue gas decreased to 30⁻40%. The PSA (pressure swing adsorption), which has been widely used for CO₂ removal from the shifting gases of ammonia synthesis in China, was applied to capture CO₂ during oxy-enrich combustion. The technological economics of oxy-enrich combustion with PSA was calculated and compared to that of oxy-fuel combustion. The results indicated that, compared with oxy-fuel combustion: (1) the oxy-enrich combustion has fewer capital and operating costs for the ASU (air separation unit) and the r... [more]
Multi-Objective Optimal Design of Renewable Energy Integrated CCHP System Using PICEA-g
Guozheng Li, Rui Wang, Tao Zhang, Mengjun Ming
June 23, 2020 (v1)
Keywords: CCHP, FEL, FTL, isolated-mode, multi-objective optimization, Renewable and Sustainable Energy
The integration of renewable energies into combined cooling, heating, and power (CCHP) systems has become increasingly popular in recent years. However, the optimization of renewable energies integrated CCHP (RECCHP) systems (i.e., optimal component configurations) is far from being well addressed, especially in isolated mode. This study aims to fill this research gap. A multi-objective optimization model characterizing the system reliability, system cost, and environmental sustainability is constructed. In this model, the objectives include minimization of annual total cost (ATC), carbon dioxide emission (CDE), and loss of energy supply probability (LESP). The decision variables representing the configuration of the RECCHP system include the number of photovoltaic (PV) panels and wind turbines (WTs), the tilt angle of PV panels, the height of WTs, the maximum fuel consumption, and the capacity of battery and heat storage tanks (HSTs). The multi-objective model is solved by a multi-obj... [more]
Performance Analysis and Optimization of a Parabolic Trough Solar Power Plant in the Middle East Region
Praveen R. P., Mohammad Abdul Baseer, Ahmed Bilal Awan, Muhammad Zubair
June 23, 2020 (v1)
Keywords: concentrated solar power, Middle East, Optimization, parabolic trough collector, Renewable and Sustainable Energy, thermal energy storage
The Middle East is one among the areas of the world that receive high amounts of direct solar radiation. As such, the region holds a promising potential to leverage clean energy. Owing to rapid urbanization, energy demands in the region are on the rise. Along with the global push to curb undesirable outcomes such as air pollution, emissions of greenhouse gases, and climate change, an urgent need has arisen to explore and exploit the abundant renewable energy sources. This paper presents the design, performance analysis and optimization of a 100 MWe parabolic trough collector Solar Power Plant with thermal energy storage intended for use in the Middle Eastern regions. Two representative sites in the Middle East which offer an annual average direct normal irradiance (DNI) of more than 5.5 kWh/m²/day has been chosen for the analysis. The thermodynamic aspect and annual performance of the proposed plant design is also analyzed using the System Advisor Model (SAM) version 2017.9.5. Based on... [more]
Process Optimization of Microwave Assisted Simultaneous Distillation and Extraction from Siam cardamom using Response Surface Methodology
Panawan Suttiarporn, Nalin Wongkattiya, Kittisak Buaban, Pisit Poolprasert, Keerati Tanruean
June 22, 2020 (v1)
Keywords: 1,8-cineole, leaf sheath of Siam cardamom, microwave-assisted simultaneous distillation and extraction, response surface methodology
The main goal of the research was to optimize microwave-assisted simultaneous distillation and extraction (MA-SDE) using response surface methodology (RSM), based on Box−Behnken design (BBD). A process was designed to extract the essential oil from the leaf sheath of Siam cardamom. The experimental data were fitted to quadratic equations, and the experiment conditions for optimal extraction of 1,8-cineole were extraction time 87.68 min, material-to-water ratio 1:13.18 g/mL and microwave power 217.77 W. Under such conditions, the content of 1,8-cineole was 157.23 ± 4.23 µg/g, which matched with the predicted value. GC−MS results indicated the presence of predominant oxygenated monoterpenes including 1,8-cineole (20.63%), iso-carveol (14.30%), cis-p-mentha-1(7),8-dien-2-ol (12.27%) and trans-p-2,8-menthadien-1-ol (9.66%), and oxygenated contents were slightly higher in the MA-SDE and extraction compared to usual SDE. In addition, the essential oil extracted by MA-SDE exhibited strong ant... [more]
Petroleum Hydrocarbon Removal from Wastewaters: A Review
Leili Mohammadi, Abbas Rahdar, Edris Bazrafshan, Hamid Dahmardeh, Md. Abu Bin Hasan Susan, George Z. Kyzas
June 22, 2020 (v1)
Keywords: Adsorption, advanced oxidation, coagulation, oil compounds, removal methods
Oil pollutants, due to their toxicity, mutagenicity, and carcinogenicity, are considered a serious threat to human health and the environment. Petroleum hydrocarbons compounds, for instance, benzene, toluene, ethylbenzene, xylene, are among the natural compounds of crude oil and petrol and are often found in surface and underground water as a result of industrial activities, especially the handling of petrochemicals, reservoir leakage or inappropriate waste disposal processes. Methods based on the conventional wastewater treatment processes are not able to effectively eliminate oil compounds, and the high concentrations of these pollutants, as well as active sludge, may affect the activities and normal efficiency of the refinery. The methods of removal should not involve the production of harmful secondary pollutants in addition to wastewater at the level allowed for discharge into the environment. The output of sewage filtration by coagulation and dissolved air flotation (DAF) floccul... [more]
Design and Optimization of Fluidized Bed Reactor Operating Conditions for Struvite Recovery Process from Swine Wastewater
Soomin Shim, Seunggun Won, Arif Reza, Seungsoo Kim, Naveed Ahmed, Changsix Ra
June 10, 2020 (v1)
Keywords: fluidized bed reactor, nutrient removal, process optimization, response surface methodology, struvite, swine wastewater
Struvite crystallization using fluidized bed reactors (FBRs) is one of the most commonly used methods for nutrient recovery from different waste streams. However, struvite recovery from swine wastewater containing much higher solids using FBR has not been studied extensively. In this study, we therefore designed and optimized the key operating conditions parameters, i.e., pH (9.0, 9.5, and 10.0), circulation rate (CR) (1.5, 3.0, and 4.5 L/Lreactor·h), and hydraulic retention time (HRT) (1, 3, and 5 h) of FBR to ensure efficient nutrient removal and struvite crystallization from swine wastewater using response surface methodology (RSM) with central composite design (CCD) as experimental design. A magnesium/phosphorus (Mg/P) molar ratio of 1.3 was maintained with MgCl2 according to ortho-phosphate (O-P) concentration of influent and an air diffuser was set to supply air with 0.03 L air/Lreactor·min. The O-P recovery efficiency of over 91% was achieved through the entire runs. Among the o... [more]
Forward Osmosis: A Critical Review
Mehrdad Mohammadifakhr, Joris de Grooth, Hendrik D. W. Roesink, Antoine J. B. Kemperman
June 10, 2020 (v1)
Keywords: concentration polarization, forward osmosis, membrane support, structural parameter
The use of forward osmosis (FO) for water purification purposes has gained extensive attention in recent years. In this review, we first discuss the advantages, challenges and various applications of FO, as well as the challenges in selecting the proper draw solution for FO, after which we focus on transport limitations in FO processes. Despite recent advances in membrane development for FO, there is still room for improvement of its selective layer and support. For many applications spiral wound membrane will not suffice. Furthermore, a defect-free selective layer is a prerequisite for FO membranes to ensure low solute passage, while a support with low internal concentration polarization is necessary for a high water flux. Due to challenges affiliated to interfacial polymerization (IP) on non-planar geometries, we discuss alternative approaches to IP to form the selective layer. We also explain that, when provided with a defect-free selective layer with good rejection, the membrane su... [more]
Technoeconomic Analysis of a Waste Tire to Liquified Synthetic Natural Gas (SNG) energy system
Avinash S. R. Subramanian, Truls Gundersen, Thomas A. Adams II
June 1, 2020 (v1)
Keywords: CO2 capture,, Gasification, Rubber, Synthetic Natural Gas (SNG), Waste tire, Waste-to-Energy
Thermochemical conversion of solid wastes through gasification offers the
dual benefit of production of high-value fuels and environmentally friendly
waste disposal. In this paper, we propose a novel process for production of
liquified synthetic natural gas (SNG) from waste tires via a rotary kiln gasification process. We use a combination of experimental data available in the
open literature, first principles mathematical models and empirical models to
study three design cases (without CCS, with precombustion CCS and with
pre- and postcombustion CCS) in two locations (USA and Norway). The
thermodynamic, economic and environmental performance of the concept is
studied. The results show that minimum selling prices of 16.7, 17.5 and 19.9
$/GJ_LHV,SNG are required for USA and 20.9, 21.8 and 24.9 $/GJ_LHV,SNG
for Norway. We note that these prices may become competitive under certain
regulatory conditions (such as recent public policy movement in British
Columbia, Canada requiri... [more]
Phenolic Compounds Extraction of Arbutus unedo L.: Process Intensification by Microwave Pretreatment
Agostinho M. R. C. Alexandre, Ana A. Matias, Maria Rosário Bronze, Maria Jose Cocero, Rafael Mato
May 22, 2020 (v1)
Keywords: Arbutus unedo, microwave pretreatment, phenolic compounds, Process Intensification
Arbutus unedo L., commonly known as the strawberry-tree fruit, is an endemic species of the Mediterranean flora. Microwave extraction technology has been considered as a fast and “green” method for the production of extracts rich in bioactive compounds, although the energy consumption is high. To overcome this bottleneck, microwave was used as a pretreatment procedure in short time periods. This technique promotes the burst of intracellular vacuoles leading to an increase in the lixiviation of phenolic compounds. Different approaches were tested, namely a solvent-free irradiation (SFI), a solvent-assisted irradiation (SAI) and a pressurized solvent-assisted irradiation (PSAI). After irradiation, a solid−liquid extraction procedure was performed using a mixture of water and ethanol. A kinetic evaluation of the total phenolic content (TPC) was performed using the Folin−Ciocalteu method. For the total anthocyanin content, a UV-spectrophotometric method was used. HPLC-UV and LC-MS were use... [more]
The Influence of Freezing and Thawing on the Yield and Energy Consumption of the Celeriac Juice Pressing Process
Rafał Nadulski, Zbigniew Kobus, Tomasz Guz
May 22, 2020 (v1)
Keywords: celery root, freezing, juice properties, pressing, specific energy, thawing, yield
The aim of this study is to indicate the influence of pretreatment, consisting of grinding vegetables and then freezing and thawing the raw material before pressing on the process efficiency and quality of obtained juice. The subject of the research was celeriac root (Apium graveolens L) of the Edward variety. Juice pressing was carried out in a laboratory basket press. The pressing yield and specific energy were values characterizing the pressing process, while pH and the extracted content in the juice were used to assess the juice quality. The experiment was performed according to three procedures. In each of them, the ground celeriac root (pulp or chips) was initially pretreated through freezing and thawing and then pressed twice. Among the examined methods of obtaining juice, the most beneficial method was pressing juice from the pulp, then freezing and thawing the pomace obtained in the first cycle, and finally, pressing the pomace. It is an energy-optimal method and guarantees a... [more]
Green Separation and Extraction Processes: Part I
George Z. Kyzas, Kostas A. Matis
May 22, 2020 (v1)
Supercritical fluid extraction comprises a known technology applied to obtain volatile compounds from flowers, i [...]
Optimum Design of a Standalone Solar Photovoltaic System Based on Novel Integration of Iterative-PESA-II and AHP-VIKOR Methods
Hussein Mohammed Ridha, Chandima Gomes, Hashim Hizam, Masoud Ahmadipour, Dhiaa Halboot Muhsen, Saleem Ethaib
May 22, 2020 (v1)
Keywords: AHP, numerical method, optimal sizing, PESA-II, standalone PV system, storage battery
Solar energy is considered one of the most important renewable energy resources, and can be used to power a stand-alone photovoltaic (SAPV) system for supplying electricity in a remote area. However, inconstancy and unpredictable amounts of solar radiation are considered major obstacles in designing SAPV systems. Therefore, an accurate sizing method is necessary to apply in order to find an optimal configuration and fulfil the required load demand. In this study, a novel hybrid sizing approach was developed on the basis of techno-economic objectives to optimally size the SAPV system. The proposed hybrid method consisted of an intuitive method to estimate initial numbers of PV modules and storage battery, an iterative approach to accurately generate a set of wide ranges of optimal configurations, and a Pareto envelope-based selection algorithm (PESA-II) to reduce large configuration by efficacy obtaining a set of Pareto front (PF) solutions. Subsequently, the optimal configurations were... [more]
Multi-Objective Optimal Configuration of the CCHP System
Liukang Zheng, Xiaoli Wang, Baochen Jiang
May 22, 2020 (v1)
Keywords: combined cooling, environmental benefits, heating and power (CCHP) system, microgrid, Optimization, particle swarm optimization (PSO), reliability
The combined cooling, heating and power (CCHP) system not only has high energy efficiency but also has different load structures. Traditional separate production (SP) system and power supply system do not consider the land cost in terms of the environmental benefits, and in the aspect of the power supply reliability, the grid-connected inverter cost is also ignored. Considering the deficiency of the traditional energy supply system, this paper builds the CCHP system construction cost model. The particle swarm optimization (PSO) is adopted to find out the minimum value of the construction cost, and the optimal system construction scheme is constructed from three aspects which are system reliability, economic benefits and environmental benefits. In this paper, the typical daily data, as well as the meteorological data and the load data, in the last four years are taken as experimental dataset. The experimental results show that compared with the traditional SP system and power supply sys... [more]
Analysis of the Sieve Unit Inclination Angle in the Cleaning Process of Oat Grain in a Rotary Cleaning Device
Zbigniew Krzysiak, Waldemar Samociuk, Janusz Zarajczyk, Zdzisław Kaliniewicz, Daniel Pieniak, Marcin Bogucki
May 22, 2020 (v1)
Keywords: conical sieve, grain separation, oat grain, rotary cleaning device
The article presents some of the research on the wider work related to testing and improving a new rotary cleaning device. The new cereal grain cleaning and separation device can support the development of sustainable agriculture in terms of seed purity and quality. This device is especially useful for small and medium-sized farms. This device has the characteristics of a multi-stage screen aided by an air stream (i.e., by pneumoseparation). The prototype was constructed at the University of Life Sciences in Lublin. The research was conducted at a test stand, which allowed changes in the operating parameters of the cleaner and their measurement. The scope of the tests included determining the influence of the inclination angle of the sieve unit (α) on the effectiveness and efficiency of oat grain cleaning. The experiment was carried out using two rotational spindle speeds: 5 and 75 rpm. The quality of the separation and cleaning of oat grains was evaluated using six cleaning process pa... [more]
Increased Energy Efficiency of a Backward-Feed Multiple-Effect Evaporator Compared with a Forward-Feed Multiple-Effect Evaporator in the Cogeneration System of a Sugar Factory
Somchart Chantasiriwan
May 22, 2020 (v1)
Keywords: counter-current, Energy Efficiency, heat exchanger, mathematical model
The cogeneration system of a sugar factory consists of boiler, steam turbine, and sugar juice evaporation process. The multiple-effect evaporator used for the conventional sugar juice evaporation process is the forward-feed multiple-effect evaporator, in which steam and sugar juice flow in the same direction. The main objective of this paper is to investigate the energy efficiency of the backward-feed multiple-effect evaporator, in which steam and sugar juice flow in opposite directions, compared with that of the forward-feed multiple-effect evaporator. Mathematical models are developed for both multiple-effect evaporators, and used to compare the performances of two cogeneration systems that use the forward-feed and backward-feed multiple-effect evaporators. The forward-feed multiple-effect evaporator requires extracted steam from a turbine at one pressure, whereas the backward-feed multiple-effect evaporator requires steam extraction at two pressures. Both evaporators have the same t... [more]
Wastewater Treatment Processes: Part I
George Z. Kyzas, Kostas A. Matis
May 22, 2020 (v1)
Cheap and plentiful, water was for centuries a manufacturing tool that industry took for granted [...]
Outdoor Large-Scale Cultivation of the Acidophilic Microalga Coccomyxa onubensis in a Vertical Close Photobioreactor for Lutein Production
Juan-Luis Fuentes, Zaida Montero, María Cuaresma, Mari-Carmen Ruiz-Domínguez, Benito Mogedas, Inés Garbayo Nores, Manuel González del Valle, Carlos Vílchez
May 22, 2020 (v1)
Keywords: carotenoids, extremophiles, microalgal biotechnology
The large-scale biomass production is an essential step in the biotechnological applications of microalgae. Coccomyxa onubensis is an acidophilic microalga isolated from the highly acidic waters of Río Tinto (province of Huelva, Spain) and has been shown to accumulate a high concentration of lutein (9.7 mg g−1dw), a valuable antioxidant, when grown at laboratory-scale. A productivity of 0.14 g L−1 d−1 was obtained by growing the microalga under outdoor conditions in an 800 L tubular photobioreactor. The results show a stable biomass production for at least one month and with a lutein content of 10 mg g−1dw, at pH values in the range 2.5−3.0 and temperature in the range 10−25 °C. Culture density, temperature, and CO2 availability in highly acidic medium are rate-limiting conditions for the microalgal growth. These aspects are discussed in this paper in order to improve the outdoor culture conditions for competitive applications of C. onubensis.
Modeling of Novel Thermodynamic Cycles to Produce Power and Cooling Simultaneously
Wilfrido Rivera, Karen Sánchez-Sánchez, J. Alejandro Hernández-Magallanes, J. Camilo Jiménez-García, Alejandro Pacheco
May 18, 2020 (v1)
Keywords: absorption cooling cycles, ammonia-water, Goswami cycle, simultaneous power and cooling
Thermodynamic cycles to produce power and cooling simultaneously have been proposed for many years. The Goswami cycle is probably the most known cycle for this purpose; however, its use is still very limited. In the present study, two novel thermodynamic cycles based on the Goswami cycle are presented. The proposed cycles use an additional component to condense a fraction of the working fluid produced in the generator. Three cycles are modeled based on the first and second laws of thermodynamics: Two new cycles and the original Goswami cycle. The results showed that in comparison with the original Goswami cycle, the two proposed models are capable of increasing the cooling effect, but the cycle with flow extraction after the rectifier presented higher irreversibilities decreasing its exergy efficiency. However, the proposed cycle with flow extraction into the turbine was the most efficient, achieving the highest values of the energy utilization factor and the exergy efficiency. It was... [more]
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