scholarly journals Photosensitizing Furocoumarins: Content in Plant Matrices and Kinetics of Supercritical Carbon Dioxide Extraction

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3805
Author(s):  
Łukasz Woźniak ◽  
Marzena Połaska ◽  
Krystian Marszałek ◽  
Sylwia Skąpska
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Cell Model ◽  
Intact Cell ◽  
Total Content ◽  
Dry Weight ◽  
Hplc Method ◽  
Chrastil Equation ◽  
The Impact ◽  
Supercritical Carbon

Furocoumarins are a group of plant phytoalexins exhibiting various bioactive properties; the most important of which are photosensitization and alteration of P450 cytochrome activity. Supercritical fluid extraction with carbon dioxide has been proposed as a green alternative for an organic solvent extraction of the furocoumarins. Four plant matrices rich in furocoumarins were extracted with CO2 at a temperature of 80 °C and pressure of 40 MPa, as these conditions were characterized by the highest solubility of furocoumarins. The extracts collected were analyzed using the HPLC method and the results obtained were used for the mathematical modeling of the observed phenomena. The total content of the furocoumarins in the matrices was 4.03–26.45 mg g−1 of dry weight. The impact of the process parameters on the solubility was consistent with the Chrastil equation. The broken plus intact cell model proved to be suitable to describe extraction curves obtained. The research proved the possibility of supercritical carbon dioxide utilization for the extraction of the furocoumarins from plant material and provided valuable data for prospective industrial-scale experiments.

scholarly journals Extraction of Triterpenic Acids and Phytosterols from Apple Pomace with Supercritical Carbon Dioxide: Impact of Process Parameters, Modelling of Kinetics, and Scaling-Up Study

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2790 ◽  
Author(s):  
Łukasz Woźniak ◽  
Anna Szakiel ◽  
Cezary Pączkowski ◽  
Krystian Marszałek ◽  
Sylwia Skąpska ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Process Parameters ◽  
Binary Systems ◽  
Cell Model ◽  
Intact Cell ◽  
Selective Extraction ◽  
Apple Pomace ◽  
Extraction Curve ◽  
Hydrophobic Compounds ◽  
The Impact

Apple pomace, a byproduct of juice production, is a rich source of bioactive compounds and nutrients. Supercritical fluid extraction was proposed as a method for a fast and selective extraction of hydrophobic compounds with a pharmaceutical potential from this matrix. Chromatographic analysis showed that the pomace contained significant amounts of such substances, the most abundant of them were ursolic acid, oleanolic acid, and β-sitosterol. The solubility was chosen as a primary factor for a selection of the extraction conditions; the best results were acquired for a temperature of 80 °C and a pressure of 30 MPa. The equation proposed by Chrastil was applied for the description of the impact of the process parameters on the solubility of the analytes; the obtained values of coefficients of determination were satisfactory, despite the fact that the equation was developed for binary systems. The extraction curves obtained during the experiments were used for the description of the process kinetics using the Broken plus Intact Cell model. The impact of the temperature, pressure, and flow rate of carbon dioxide on the mass transfer phenomena was investigated. The data obtained allowed the prediction of the extraction curve for the process conducted on the larger scale.

Understanding the Impact of Supercritical Carbon Dioxide on the Delignification Mechanism During Organosolv Pulping: A Model Compound Study

2012 ◽  
Vol 32 (3) ◽  
pp. 225-237 ◽  
Author(s):  
Michael Schrems ◽  
Falk Liebner ◽  
Markus Betz ◽  
Martin Zeilinger ◽  
Stefan Böhmdorfer ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Model Compound ◽  
Organosolv Pulping ◽  
The Impact ◽  
Supercritical Carbon

Structural Design Considerations for Tubular Power Tower Receivers Operating at 650°C

2014 ◽  
Author(s):  
Ty W. Neises ◽  
Michael J. Wagner ◽  
Allison K. Gray
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Supercritical Carbon Dioxide ◽  
Performance Metrics ◽  
Operating Conditions ◽  
Design Parameters ◽  
Outlet Temperature ◽  
Power Cycles ◽  
The Impact ◽  
Supercritical Carbon

Research of advanced power cycles has shown supercritical carbon dioxide power cycles may have thermal efficiency benefits relative to steam cycles at temperatures around 500–700°C. To realize these benefits for CSP, it is necessary to increase the maximum outlet temperature of current tower designs. Research at NREL is investigating a concept that uses high-pressure supercritical carbon dioxide as the heat transfer fluid to achieve a 650°C receiver outlet temperature. At these operating conditions, creep becomes an important factor in the design of a tubular receiver and contemporary design assumptions for both solar and traditional boiler applications must be revisited and revised. This paper discusses lessons learned for high-pressure, high-temperature tubular receiver design. An analysis of a simplified receiver tube is discussed, and the results show the limiting stress mechanisms in the tube and the impact on the maximum allowable flux as design parameters vary. Results of this preliminary analysis indicate an underlying trade-off between tube thickness and the maximum allowable flux on the tube. Future work will expand the scope of design variables considered and attempt to optimize the design based on cost and performance metrics.

scholarly journals Influence of Supercritical Carbon Dioxide Brayton Cycle Parameters on Intelligent Circulation System and Its Optimization Strategy

2021 ◽  
Vol 2066 (1) ◽  
pp. 012074
Author(s):  
Kai Li ◽  
Kai Sun
Keyword(s):  
Carbon Dioxide ◽  
Power Generation ◽  
Supercritical Carbon Dioxide ◽  
Circulation System ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Optimization Strategy ◽  
Cycle System ◽  
The Impact ◽  
Supercritical Carbon

Abstract The supercritical carbon dioxide (SCO2) Brayton cycle takes advantage of the special physical properties of carbon dioxide near the critical point (31.1 °C, 7.39MPa), and has higher energy conversion efficiency than the current large-scale steam power cycle. This cycle can be widely used in the field of power generation, but a lot of research work is still needed in terms of component parameters and layout under different working conditions. In this regard, the purpose of this paper is to study the influence of supercritical carbon dioxide Brayton cycle parameters on cycle efficiency and its optimization strategy. Based on the first law of thermodynamics, this paper uses Aspen Plus software to establish S-CO2 Brayton cycle system models with different circulation arrangements. In this paper, the existing algorithm of the simulation system and the newly-built algorithm are used to build the S-CO2 shunt and recompression Brayton cycle system model, and the accuracy of the model is verified with experimental data from literature. Then this paper conducts disturbance experiments on the model to study the influence of heater heating, valve opening and precooler cooling on the system, and analyze the dynamic characteristics of the system. Experimental results show that the thermal efficiency of the simple Brayton cycle is much lower than that of the recompression Brayton cycle and the split recompression Brayton cycle under higher parameters. The compressor outlet pressure and the turbine inlet temperature have an effect on the efficiency of the recompression Brayton cycle. The impact is significant, and the optimal value of the compressor shunt coefficient is between 0.5-0.7, which provides a reference for the layout optimization method of the SCO2 Brayton cycle and the optimization of the same type of power generation cycle.

scholarly journals Screening of Functional Compounds in Supercritical Carbon Dioxide Extracts from Perennial Herbaceous Crops

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 488
Author(s):  
Mateusz Ostolski ◽  
Marek Adamczak ◽  
Bartosz Brzozowski ◽  
Mariusz Jerzy Stolarski
Keyword(s):  
Carbon Dioxide ◽  
Antioxidant Activity ◽  
Spectral Analysis ◽  
Supercritical Carbon Dioxide ◽  
Total Content ◽  
Miscanthus Sinensis ◽  
Growing Period ◽  
Herbaceous Crops ◽  
Miscanthus Sacchariflorus ◽  
Supercritical Carbon

The bio-based economy concept requires using biomass not only for energy production but also for bioactive compound extraction, application or biotransformation. This study analyzed the possibility of obtaining bioactive compounds from biomass before its transformation into biofuel. This involved an analysis of the total content of polyphenols (TPC), flavonoids (TFC), and spectral analysis using Fourier transform infrared spectroscopy (QATR- FTIR) as well as analysis of the antioxidant activity of extracts from selected perennial herbaceous crops cultivated on marginal lands in Poland. The extracts were obtained by supercritical carbon dioxide extraction (scCO2) or scCO2 with water as a cosolvent (scCO2/H2O) from biomass of the following plants: Helianthus salicifolius, Silphium perfoliatum, Helianthus tuberosus, Miscanthus × giganteus, Miscanthus sacchariflorus, Miscanthus sinensis and Spartina pectinata. The biomass was harvested twice during the growing period (June and October) and once after the end of the growing period (February). For most of the analyzed extracts obtained from biomass at the growing stage using scCO2 or scCO2/H2O, a higher TPC was noted than for samples of semi-wood or straw biomass obtained after the end of the growing period. Higher contents of polyphenolic compounds were recorded in extracts obtained using scCO2/H2O. A positive correlation between TPC and antioxidant activity was noted for the analyzed substrates. Flavonoid contents varied in the analyzed samples, and higher contents were generally obtained in scCO2 extracts from biomass harvested at the beginning of the growing period. A high diversity of extract compositions was confirmed by spectral analysis. The presented data can be used at the initial stage of planning a biorefinery.

scholarly journals Nonlinear Heat Transfer From Particles in Supercritical Carbon Dioxide Near the Critical Point

2019 ◽  
Vol 12 (3) ◽  
Author(s):  
Michael James Martin ◽  
Elizabeth G. Rasmussen ◽  
Shashank Yellapantula
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Thermal Conductivity ◽  
Supercritical Carbon Dioxide ◽  
Critical Point ◽  
Materials Synthesis ◽  
Energy Technologies ◽  
Property Changes ◽  
The Impact ◽  
Supercritical Carbon

Abstract Particle to fluid heat transfer in supercritical carbon dioxide (sCO2) is encountered in energy technologies and in materials synthesis. Near the critical point, the extreme pressure and temperature sensitivity of sCO2’s thermal conductivity will change the expected heat transfer in these systems. The current work combines the Kirchoff transformation for thermal conductivity with the conduction shape factor for a sphere, allowing prediction of heat transfer in these systems and quantification of the impact of these property changes. Results show that the heat transfer is non-linear for supercritical heat transfer, with the non-linearity particularly significant near the critical point. The results also show that approaches such as an average thermal conductivity based on film temperature are unlikely to accurately predict heat transfer in this region. The methods described in this paper can be applied to fluid–particle heat transfer at low Reynolds number in other fluids with large variations in thermal conductivity.

OPTIMIZATION OF CURCUMA LONGA L. RHIZOME SUPERCRITICAL CARBON DIOXIDE EXTRACTION (SC-CO2) BY RESPONSE SURFACE METHODOLOGY (RSM)

2016 ◽  
Vol 78 (6-6) ◽  
Author(s):  
Siti Hafsah Mohd Shah ◽  
Zaibunnisa Abdul Haiyee ◽  
Khudzir Ismail ◽  
Nooraain Hashim ◽  
Wan Iryani Wan Ismail
Keyword(s):  
Carbon Dioxide ◽  
Response Surface Methodology ◽  
Supercritical Carbon Dioxide ◽  
Response Surface ◽  
Curcuma Longa ◽  
Dry Weight ◽  
Supercritical Carbon Dioxide Extraction ◽  
Carbon Dioxide Extraction ◽  
Percentage Yield ◽  
Supercritical Carbon

Fast, selective and reliable extraction technique namely Supercritical Carbon Dioxide Extraction (SC-CO2) has been proposed in this study. Experiments were carried out to determine the optimum conditions for pressure and temperature of SC-CO2 extraction for Curcuma longa L. using response surface methodology (RSM) based on central composite design (CCD) with the aim to obtain the highest percentage of yield and curcuminoid concentration. At a pressure of 4807 psi and temperature of 90°C, extraction of turmeric rhizome using SC-CO2 extraction resulted in oil yield of 7.54% (dry weight basis) and curcuminoid concentration of 0.023 mg 100-1g of dry turmeric rhizome. From the study, it can be concluded that the percentage yield and curcuminoid concentration was significantly influenced by pressure and temperature.

scholarly journals An Optimization Study to Evaluate the Impact of the Supercritical CO2 Brayton Cycle’s Components on Its Overall Performance

2021 ◽  
Vol 11 (5) ◽  
pp. 2389
Author(s):  
Khaled Alawadhi ◽  
Abdullah Alfalah ◽  
Bashar Bader ◽  
Yousef Alhouli ◽  
Ahmed Murad
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Power Systems ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Optimization Study ◽  
The Impact ◽  
Sustainable Power ◽  
Supercritical Carbon

The rising environmental problems due to fossil fuels’ consumption have pushed researchers and technologists to develop sustainable power systems. Due to properties such as abundance and nontoxicity of the working fluid, the supercritical carbon (sCO2) dioxide Brayton cycle is considered one of the most promising technologies among the various sustainable power systems. In the current study, a mathematical model has been developed and coded in Matlab for the recompression of the supercritical carbon dioxide Brayton cycle sCO2-BC. The real gas properties of supercritical carbon dioxide (sCO2) were incorporated into the program by pairing the NIST’s Refporp with Matlab© through a subroutine. The impacts of the various designs of the cycle’s individual components have been investigated on the performance of sCO2−BC. The impact of various sedative cycle parameters, i.e., compressor’s inlet temperature (T1), and pressure (P1), cycle pressure ratio (Pr), and split mass fraction (x), on the cycle’s performance (ηcyc) were studied and highlighted. Moreover, an optimization study using the genetic algorithm was carried out to find the abovementioned cycle’s optimized values that maximize the cycle’s per-formance under provided design constraints and boundaries.

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