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Bioactive Proteins and Peptides from Agro-Industrial Waste
Published in Anil Kumar Anal, Parmjit S. Panesar, Valorization of Agro-Industrial Byproducts, 2023
Nuntarat Boonlao, Thatchajaree Mala, Sushil Koirala, Anil Kumar Anal
Supercritical extraction is characterized by the occurrence of changes in temperature and pressure such that gas turns into a supercritical fluid, resulting in the formation of a distinct liquid and gas phase. The solvent supercritical fluid flow takes place with a transfer mass where solvent convection is the dominant transport mechanism (Soquetta, Terra, and Bastos, 2018). While other new extraction techniques are still in the research stages, SpFE has already left the laboratory since it has previously been used in the industry. Furthermore, owing to its unique properties, CO2 is the most commonly utilized solvent in SpFE. This is due to its low critical temperature and pressure (31.1°C and 7.38 MPa, respectively), which is crucial for the preservation of bioactive compounds in extracts, along with being an inert solvent, as reported by Chemat et al. (2019). Carbon dioxide is non-toxic, cheap, non-explosive, widely available, easily extracted, and well suited for separation purposes (Freitas et al., 2021). Figure 7.8 demonstrates the extraction of a selected sample using SpFE.
Other Modification Processes
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
A supercritical fluid is a substance at a temperature and pressure above its critical point, where neither a distinct liquid nor a distinct gas phase exists, but which behaves as a gas and a liquid, effusing through solids like a gas, and dissolving materials like a liquid. As can be seen in Figure 5.11, a supercritical fluid exists at a critical pressure and temperature point where the properties of gases and liquids merge, where there is a convergence of the critical temperature (the highest temperature at which a gas can be converted into a liquid by an increase in pressure) and the critical pressure (the highest pressure at which a liquid can be converted into a gas by an increase in the temperature).
Morphology of Cavitation
Published in Dmitry A. Biryukov, Denis N. Gerasimov, Eugeny I. Yutin, Cavitation and Associated Phenomena, 2021
Dmitry A. Biryukov, Denis N. Gerasimov, Eugeny I. Yutin
Note that the boiling curve ends at a certain point—this is the so-called critical point C; at parameters higher than the parameters of the critical point, phase transition is impossible since there are no separate phases; in that region, the substance is the so-called ‘supercritical fluid’, which is neither a liquid nor a gas.
Removal of AAEMs from high alkali coal under supercritical CO2 fluid-citric acid extraction system
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Junwei Guo, Mingrui Zhang, Guanghui Yan, Zhenxing Zhang, Pengfei Zhao, Mengyao Guo, Bo Zhang
In recent years, supercritical fluid extraction has begun to be applied to the extraction of various metal elements (Ding et al. 2017; Leybros et al. 2017). It is a potential extraction technology which uses supercritical fluid as extraction solvent to separate the extracted matter from the sample matrix. Compared with the normal temperature and pressure leaching process, it has the advantages of faster extraction speed and higher extraction rate, and can minimize the use of organic solvents and the production of waste solvents (Reisdörfer, Bertuol, and Tanabe 2020). CO2 is the most used solvent for supercritical fluid extraction due to the advantages of critical temperature close to room temperature, low critical pressure, chemical inertness, wide source and low price (Das et al. 2018). Supercritical CO2 fluid has lower viscosity and higher diffusion rate, making it effective to extract solute from solid or liquid matrix (Krivonos and Belskaya 2020). With such excellent properties, supercritical CO2 fluid extraction technology has a wide range of application prospects in mineral processing (van Dyk et al. 2022; Yuan et al. 2022).
Heat Transfer Characteristics of CO2 in a Horizontal Tube under Subcritical and Supercritical Pressures
Published in Heat Transfer Engineering, 2023
Chengrui Zhang, Bingtao Hao, Liangyuan Cheng, Jinliang Xu, Qingyang Wang
Supercritical fluids have been widely used in a variety of applications including food processing, separation and purification, and materials synthesis [1, 2]. Supercritical CO2 (sCO2) is attracting significant interests. Due to the high global warming potential of the traditional refrigerants such as R22, R32 and R134a, CO2 as a natural refrigerant is considered an alternative, and trans-critical CO2 cycles have been applied in vehicle and residential air conditioning and industrial refrigeration [3, 4]. For power generation, supercritical CO2 Brayton cycles have higher efficiency, more compactness, and better flexibility than traditional water steam cycles, and is thus widely studied for solar thermal, fossil fuel, and nuclear power plants [5]. Investigation of the heat transfer characteristics of sCO2 in tubes can provide guidance for the design and operation of these cycles and is thus important for refrigeration and power generation applications.
Numerical analysis on supercritical natural convection by lattice Boltzmann method
Published in Numerical Heat Transfer, Part B: Fundamentals, 2020
Jianqi Zhu, Shihua Lu, Dongyan Gao, Weiwei Chen, Xinjun Li
With the industrialization process accelerating, the supercritical fluid has become the focus of researchers. Supercritical fluid, which is a special state fluid between liquid and gas, its thermal–physical properties are susceptible to temperature and pressure. Because of its multiple properties of gas and liquid, it is widely used in high-tech fields such as thermal engineering, chemical engineering, low-temperature superconducting, refrigeration and air conditioning, and aviation technology [21]. For instance, supercritical CO2 was used to study the heat transfer in the tube [22]. Considering the particularity of the rapid change of thermal–physical properties of supercritical fluid near the critical point, some scholars had begun to apply supercritical fluids to study the heat transfer.