scholarly journals Achieving solubility alteration with functionalized polydimethylsiloxane for improving the viscosity of supercritical CO2 fracturing fluids

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17197-17205
Author(s):  
Bin Liu ◽  
Yanling Wang ◽  
Lei Liang ◽  
Yijin Zeng
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Co2 ◽  
Flow State ◽  
Fracturing Fluids

Thickened carbon dioxide flow state.

scholarly journals PRODUCTION OF EXTRACTS FROM VEGETABLE RAW MATERIALS BY CARBON DIOXIDE

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
K. Gafurov ◽  
B. Muhammadiev ◽  
Sh. Mirzaeva ◽  
F. Kuldosheva
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Co2 ◽  
Raw Materials ◽  
Maximum Yield ◽  
Volumetric Flow Rate ◽  
Extraction Process ◽  
Raw Material ◽  
Critical Conditions ◽  
Plant Materials ◽  
Laboratory Setup

The unique properties of supercritical carbon dioxide as a solvent are widely used for extraction. In supercritical media, the dissolution of molecules of various chemical nature is possible. The purpose of this investigation was to study the extraction process and obtain extracts from valuable regional plant materials by applying CO2 extraction under pre- and supercritical conditions. The objects of research were: ground seeds of melon, pumpkin and licorice roots, as well as mint leaves, mulberry and jida flowers. For extraction, a laboratory setup was used that allows extraction when the CO2 is supplied by a high-pressure plunger pump in the sub- and supercritical state using a heat pump. The pressure range is 3-15 MPa, temperatures 295–330 K, and the volumetric flow rate above the critical CO2 is 800–900 g. Experiments with ground seeds of melon and pumpkin showed that as a result of 4 sequentially performed extraction cycles on a single load with supercritical CO2 parameters ( 315–330 K; 3–7.5 MPa) the decrease in the mass of melon seeds was 90 g (pumpkins 80 g). During the total extraction time (2.5 hours), 20 kg of CO2 were pumped through the reactor (25 l at 290 K and 6.8 MPa), while the average oil content in the extract was 4 g per 1 kg of CO2 (3.0 g per 1 l of SС-CO2) In experiments with jida flowers, the maximum amount of solid extractable substance (2% by weight of the raw material) was obtained at a temperature in the extractor of 308 K and a pressure of 7.5 MPa. Upon extraction under critical conditions in collection 2, the liquid phase was absent; only a yellow-green paste was released in it. According to the results of experiments with mint leaves, the maximum yield of a greenish liquid was observed at T = 315 K and P = 4 MPa., Mulberry - at T = 306 K and P = 6.0 MPa. The results of the extraction of oils and extracts from ground seeds of melon, pumpkin and licorice roots, as well as mint leaves, mulberries and jida flowers confirm that the maximum yield of the extracted substance is achieved with supercritical CO2 parameters in the extractor (310 K, 7.5 MPa). When liquid CO2 is extracted (300 K and 6-8 MPa), up to 2% of a yellow substance is extracted, which does not differ in appearance from a supercritical extract.

scholarly journals Artificial Neural Network (FFBP-ANN) Based Grey Relational Analysis for Modeling Dyestuff Solubility in Supercritical CO2 with Ethanol as the Co-Solvent

2021 ◽  
Author(s):  
FNU SRINIDHI
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Mean Square Error ◽  
Supercritical Co2 ◽  
Mean Absolute Error ◽  
Absolute Error ◽  
Mean Square ◽  
Relational Analysis ◽  
Grey Relational ◽  
Supercritical Carbon

The research on dye solubility modeling in supercritical carbon dioxide is gaining prominence over the past few decades. A simple and ubiquitous model that is capable of accurately predicting the solubility in supercritical carbon dioxide would be invaluable for industrial and research applications. In this study, we present such a model for predicting dye solubility in supercritical carbon dioxide with ethanol as the co-solvent for a qualitatively diverse sample of eight dyes. A feed forward back propagation - artificial neural network model based on Levenberg-Marquardt algorithm was constructed with seven input parameters for solubility prediction, the network architecture was optimized to be [7-7-1] with mean absolute error, mean square error, root mean square error and Nash-Sutcliffe coefficient to be 0.026, 0.0016, 0.04 and 0.9588 respectively. Further, Pearson-product moment correlation analysis was performed to assess the relative importance of the parameters considered in the ANN model. A total of twelve prevalent semiempirical equations were also studied to analyze their efficiency in correlating to the solubility of the prepared sample. Mendez-Teja model was found to be relatively efficient with root mean square error and mean absolute error to be 0.094 and 0.0088 respectively. Furthermore, Grey relational analysis was performed and the optimum regime of temperature and pressure were identified with dye solubility as the higher the better performance characteristic. Finally, the dye specific crossover ranges were identified by analysis of isotherms and a strategy for class specific selective dye extraction using supercritical CO2 extraction process is proposed.

scholarly journals Hydromechanical-Coupled Cohesive Interface Simulation of Complex Fracture Network Induced by Hydrofracturing with Low-Viscosity Supercritical CO2

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Xin Cai ◽  
Wei Liu
Keyword(s):  
Hydraulic Fracturing ◽  
Supercritical Co2 ◽  
Fracture Propagation ◽  
Zone Model ◽  
Hydraulic Pressure ◽  
Small Aperture ◽  
Complex Fracture ◽  
Low Viscosity ◽  
Fracturing Fluids ◽  
Low Viscosity Fluids

Abstract Hydraulic fracturing experiments with low-viscosity fluids, such as supercritical CO2, demonstrate the formation of complex fracture networks spread throughout the rocks. To study the influence of viscosity of the fracturing fluids on hydraulic fracture propagation, a hydromechanical-coupled cohesive zone model is proposed for the simulation of mechanical response of rock grains boundary separation. This simulation methodology considers the synergistic effects of unsteady flow in fracture and rock grain deformation induced by hydraulic pressure. The simulation results indicate a tendency of complex fracture propagation with more branches as the viscosity of fracturing fluids decrease, which is in accord with experimental results. The low-viscosity fluid can flow into the microfractures with extremely small aperture and create more shear failed fracture. This study confirms the possibility of effective well stimulations by hydraulic fracturing with low-viscosity fluids.

scholarly journals Influence of pressure and time on extraction process using supercritical CO2

2008 ◽  
Vol 44 (1) ◽  
pp. 125-131 ◽  
Author(s):  
V. Micic ◽  
Z. Lepojevic ◽  
B. Mandic ◽  
M. Jotanovic ◽  
G. Tadic ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Co2 ◽  
Particle Diameter ◽  
Extraction Process ◽  
Salvia Officinalis ◽  
Quantitative Composition ◽  
Qualitative And Quantitative ◽  
Salvia Officinalis L ◽  
Carbon Dioxide Co2

The supercritical fluid extraction (SFE) by carbon dioxide (CO2) of Salvia officinalis L. was investigated. SFE by CO2 was performed at different pressure (80, 100, 150, 200 and 300 bar) and constant temperature of 40?C (all other extraction conditions, such are flow rate, particle diameter of Salvia officinalis, extraction time were kept constant. The GC-MS method was used for determination of qualitative and quantitative composition of obtained extracts and essential oils.

Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Applied to Transcritical Carbon Dioxide Heat Pump

2021 ◽  
pp. 451-493
Author(s):  
Chaobin Dang ◽  
Eiji Hihara
Keyword(s):  
Heat Transfer ◽  
Carbon Dioxide ◽  
Heat Pump ◽  
Supercritical Co2 ◽  
Lubricating Oil ◽  
Cross Sectional ◽  
Pump System ◽  
Heat Pump System ◽  
Transcritical Carbon Dioxide ◽  
Supercritical Water Cooled Reactor

Understanding the heat transfer characteristics of supercritical fluids is of fundamental importance in many industrial processes such as transcritical heat pump system, supercritical water-cooled reactor, supercritical separation, and supercritical extraction processes. This chapter addresses recent experimental, theoretical, and numerical studies on cooling heat transfer of supercritical CO2. A systematic study on heat transfer coefficient and pressure drop of supercritical CO2 was carried out at wide ranges of tube diameter, mass flux, heat flux, temperature, and pressure. Based on the understanding of temperature and velocity distributions at cross-sectional direction provided by the numerical simulation, a new prediction model was proposed, which agreed well with the experimental results. In addition, the effect of lubricating oil was also discussed with the focus on the change in flow pattern and heat transfer performance of oil and supercritical CO2.

scholarly journals Review of existing and development of a novel mathematical model for supercritical CO2 cycles working fluid

2018 ◽  
Vol 240 ◽  
pp. 01036
Author(s):  
Marcin Wołowicz ◽  
Jarosław Milewski ◽  
Piotr Lis
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Mathematical Model ◽  
Heat Capacity ◽  
Supercritical Co2 ◽  
Pressure Range ◽  
Critical Conditions ◽  
Working Fluid ◽  
Critical Properties ◽  
Area Of Interest

The paper aims to compare the models of working fluids against experimental data for carbon dioxide close to its critical conditions. Fortunately, most of the work is already done and published where the authors compared the models based on the equation of the state (EoS). There are a few other models which were not investigated, thus we would like to add a few new results here and focus only on near-critical properties where the biggest deviation between experimental and calculated properties can be observed. The area of interest was pressure range of 7.39 – 20 MPa and temperature range of 304-340 K just above fluid critical point (7.39 MPa, 304.25 K). Model validation was performed for density and heat capacity as one of the most important parameters in preliminary cycle analysis.

scholarly journals Effect of CO2 Preservation Treatments on the Sensory Quality of Pomegranate Juice

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5598
Author(s):  
Ana Carolina Mosca ◽  
Leonardo Menghi ◽  
Eugenio Aprea ◽  
Maria Mazzucotelli ◽  
Jose Benedito ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Supercritical Co2 ◽  
Sensory Quality ◽  
Pomegranate Juice ◽  
Process Conditions ◽  
Volatile Profile ◽  
Projective Mapping ◽  
Supercritical Carbon

Due to the interest in identifying cost-effective techniques that can guarantee the microbiological, nutritional, and sensorial aspects of food products, this study investigates the effect of CO2 preservation treatment on the sensory quality of pomegranate juice at t0 and after a conservation period of four weeks at 4 °C (t28). The same initial batch of freshly squeezed non-treated (NT) juice was subjected to non-thermal preservation treatments with supercritical carbon dioxide (CO2), and with a combination of supercritical carbon dioxide and ultrasound (CO2-US). As control samples, two other juices were produced from the same NT batch: A juice stabilized with high pressure treatment (HPP) and a juice pasteurized at high temperature (HT), which represent an already established non-thermal preservation technique and the conventional thermal treatment. Projective mapping and check-all-that-apply methodologies were performed to determine the sensory qualitative differences between the juices. The volatile profile of the juices was characterized by gas chromatography-mass spectrometry. The results showed that juices treated with supercritical CO2 could be differentiated from NT, mainly by the perceived odor and volatile compound concentration, with a depletion of alcohols, esters, ketones, and terpenes and an increase in aldehydes. For example, in relation to the NT juice, limonene decreased by 95% and 90%, 1-hexanol decreased by 9% and 17%, and camphene decreased by 94% and 85% in the CO2 and CO2-US treated juices, respectively. Regarding perceived flavor, the CO2-treated juice was not clearly differentiated from NT. Changes in the volatile profile induced by storage at 4 °C led to perceivable differences in the odor quality of all juices, especially the juice treated with CO2-US, which underwent a significant depletion of all major volatile compounds during storage. The results suggest that the supercritical CO2 process conditions need to be optimized to minimize impacts on sensory quality and the volatile profile.

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