Search

Supercritical water fluidized bed reactor (SCWFBR) is a novel concept for the gasification of coal and biomass to produce hydrogen. In this work, to enhance the mixing in the axial direction, an inclined distributor is introduced to optimize the flow dynamics in SCWFBR with partitioned fluid supply. Through numerical simulations based on the two fluid model (TFM), the effects of the inclined distributor structure and operating parameters on the solid distribution and the residence time are evaluated with the optimal values determined. Numerical results show that, area ratio = 2:1, SCW velocity ratio = 3:1, flow ratio = 3.36:1 and inclination angle = 20 ° are the optimal design in this paper. A predictive correlation of the minimum fluidization velocity for the improved SCWFBR is also proposed based on the numerical data. The average error between the correlation and numerical simulation results is approximately 1.4% which strongly demonstrates its capability. Finally, based on the optimal design, the lab-scale reactor is further scaled up and the studies about two scale-up rules are carried out. Only the cold flow is simulated in this study without considering chemical reaction which would be involved in future work.

Supercritical water (SCW) fluidized bed reactors convert biomass to fuels without pollutants emission. In this work, experimental studies were carried out to investigate voidage distribution in an SCW fluidized bed by capacitance probes. Quartz sands with different particle sizes were fluidized by SCW under system pressure of 20–27 MPa and temperature of 410–570 °C. The effect of operation conditions on voidage distributions of the emulsion phase (e.g. averaged voidage and probability density) is discussed. A predicting correlation between voidage and superficial velocity in emulsion phase is proposed. The relative error of the correlation is within ±25%. These research results provide useful guidance for the optimization of supercritical water gasification technology.

The utilization of hydrogen is gaining increasing attention due to its high heating value and environmentally friendly combustion product. The supercritical water circulating fluidized bed reactor is a promising and potentially clean technology that can generate hydrogen from coal gasification. Cyclone is a vital part of the reactor which can separate incomplete decomposition of pulverized coal particles from mixed working fluid. This paper aims to gain in-depth understanding of the cyclone separation mechanisms under supercritical fluid by computational fluid dynamics (CFD). Although the amount of supercritical carbon dioxide in mixed working fluid is minor, it obviously influences the flow fields and separation efficiency of a cyclone. The simulation results suggest that both the decreasing content of supercritical carbon dioxide and adding the extra dipleg cause the promoting performance of cyclones. Research findings could refine the design of supercritical fluid–solid cyclones.

A toad egg-inspired structure comprising bismuth (Bi) nanoparticles (NPs) contained in a carbon microrod shell (Bi@C) was synthesized via the one-pot supercritical acetone (scAct) route and subsequent carbonization. During the formation of Bi NPs in scAct in the presence of nitric acid, a few decomposed acetone molecules acted as carbon sources, which generated an albumen-like N-doped carbon microrod with an average shell thickness of 38 nm and were embedded with yolk-like Bi NPs having size in the range of 30–200 nm. The densely packed Bi NPs inside the carbon micron shell resulted in a high Bi loading of 78 wt%. When utilized for Li storage, the Bi@C delivered a high reversible capacity of 337 mAh g–1 after 70 cycles at 0.05 A g–1, long-term cyclability of 0.04 decay per cycle for 1000 cycles at 1 A g–1, and high volumetric energy density of 870 mAh cm–3. The use of a mixed ether- and ester-based electrolyte in the Bi@C cell reduced the resistivity and increased the capacitive contribution, thereby resulting in a better high-rate performance and long-term stability than those obtained using conventional ester-based electrolytes.

The present work is the first detailed description of the endothermic catalytic reaction of methylcyclohexane (MCH) over H-ZSM-5 zeolites (HZ) and activated charcoals (AC) coated in a multichannel micro-reactor module with novel ultra-compact wavy structure (MR) under supercritical conditions (550 °C, 5 MPa). The MR has an ultra-compact structure with nine micro-channels in parallel that exhibit a size of 120 × 30 mm and a total cross-sectional area of 36 cm2. The catalytic performance of the conventional tube reactor (TR) packed with HZ and AC catalysts was also studied for comparative purposes. All catalysts and reactors were characterized using various techniques such as field emission scanning electron microscope (FE-SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), ammonia temperature-programmed desorption (NH3-TPD). In general, MRs showed always a significantly enhanced MCH conversion (%) performance and heat sink compared with conventional TRs. AC-coated MR showed the highest MCH conversion (%) performance compared to the other reactors. MCH conversion (%) was higher in the following order AC-coated MR (78.70%) > AC-packed TR (70.49%) > HZ-coated MR (68.87%) > HZ-packed TR (54.81%). The AC-coated MR can be one of the candidates for a heat-absorbing reaction for aircraft cooling system control.

For dissolution enhancement of celecoxib (CLX), an anti-solvent crystallization technique in the presence of polyvinylpyrrolidone (PVP) was applied by either water (WAS), a conventional method, or supercritical CO2 as anti-solvent (SAS). Box-Behnken design with the parameters of temperature (T), pressure (P), and time required to depressurize (td) was applied to examine the effect of variables in the SAS process. In the SAS process, maximum dissolution (81.7 % after 90 min) and saturation solubility (8.6 µg/mL) were obtained when the T, P, and td were 50 °C, 300 bar, and 20 min, respectively. Optimal SAS samples exhibited a higher dissolution rate compared to particles obtained by the WAS. The presence of PVP in the SAS sample increased the solubility of CLX by 2.7-fold in comparison to untreated CLX. The greater dissolution rate of the SAS sample could arise from the formation of sponge-like particles with increased porosity, crystallinity reduction, and increased CLX solubility.

Isoamyl acetate esters were synthesized under supercritical CO2 (SC-CO2) in a continuous packed-bed reactor (PBR) using immobilized lipase (Novozym 435) as the catalyst. A fractional factorial design (24−1) was applied to evaluate the effects of pressure (10–20 MPa), temperature (40–60 °C), substrates (fusel oil + acetic anhydride) flow rate ( Q S 1 / S 2 : 0.2–0.6 mL/min), and CO2 flow rate ( Q C O 2 : 0.4–1.2 L/min) on the isoamyl acetate conversion (X, %). Results showed that only the effects of Q S 1 / S 2 were statistically significant at the level of 5%. Mathematical modeling of the PBR was applied using the law of conservation of mass that resulted in two partial differential equations for fluid and enzymes. The model was solved using finite difference methods and successfully validated with the experimental data in terms of isoamyl alcohol concentration. Finally, the model was employed to examine the impact of the input molar ratio of fusel oil per acetic anhydride (IMFA) and the length per diameter ratio (L/D) of the PBR on its performance.

For the wide industrial applications of supercritical CO2 (S-CO2) circulating fluidized bed (CFB) technology, the simulation on scale-up characteristics would be a crucial and reliable means to investigate specific combustion process before establishing costly and complex boilers in industry. This study conducted 3D CFD simulations in lab-scale, pilot-scale, and industry-scale S-CO2 CFB boilers (0.1 MW to 600 MW) based on the Eulerian-Lagrangian method. The scale-up characteristics were comprehensively discussed from the angles of furnace structure, gas-solid flow dynamic, combustion characteristics, heat transfer characteristics, gas emission characteristics, and boiler efficiency with the fitting formulas of the scaled-up regularities derived. Results show that with the power capacity increased, the heating surface area in the furnace and flue system enlarged, in which the furnace heating surface accounted for a larger proportion. The particle flow rates and the circulating ratio increased, and the voidage distribution was less affected by disturbance with more complicated core-annulus structures appeared. With the thermal input increased, furnace temperature decreased accompanied by better thermal inertia, and the heat transfer of cold walls enhanced although its transverse distribution became uneven. The emissions of CO, NOx, and SO2 from the industry-scale CFB were lower than the other two scales. The carbon conversion ratio and the combustion efficiency increased with the thermal input increased, and the growth slowed for industry-scale boiler.

Supercritical CO2 power cycles are considered to be a more effective means to replace the steam Rankine cycle in power generation by power coal in the future. However, CO2 compressors for this appl...

Supercritical high-pressure methane (CH4) adsorption analysis was performed to investigate the gas adsorption behavior and storage capacities of the Lower Cambrian Shuijingtuo Shale in the Huanglin...

International audience; Recent efforts in chemistry have led to development of a fast and continuous process for the production of synthetic talc in a supercritical hydrothermal reactor. This attractive process compatible with industrial requirements leads to advantageous physicochemical characteristics including submicrometer size, hydrophilicity, and high chemical and mineralogical purity. In addition, the high speed of the process and moderate reaction conditions have potential advantages from a viewpoint of the impacts on the environment. To verify environmental advantages and seize further opportunities to improve environmental performance, the current study evaluates the new process using the life cycle assessment (LCA) methodology. A cradle-to-gate assessment considers the production of synthetic talc from different magnesium and reagent acid precursors at different concentrations. The findings suggest high impacts of precursors (65–94%, depending on their concentration) and low impacts of process energy and water. Substituting magnesium acetate with magnesium sulfate could reduce greenhouse gases from 4.8 to 2.6 kgCO2 and cumulative energy use from 86 to 34 MJ per 1 kg of synthetic talc. Discussion draws on previous LCA studies on the supercritical hydrothermal process and applications of synthetic talc considering its environmental performance and characteristics in comparison to the conventional (natural) talc.

The effect of the water-saturated supercritical carbon dioxide (scCO2) flow rate on the corrosion behavior of API 5L X80 steel at a temperature of 35°C and pressure of 80 bar was investigated. Tests were performed with the samples attached to a rotating shaft inside an autoclave. Results indicate that increasing the scCO2 flow rate had no significant influence on the general/localized corrosion rate under the various dynamic conditions considered. The average general corrosion rate was 0.064 mm/y, while the average measured pitting penetration rates were one order of magnitude higher. The size of the corrosion features on the surface of the samples, which were believed to provide an indication as to the size of the condensed water droplets, was much smaller than the calculated critical droplet size needed to be displaced by the flow, supporting the theory as to why flow rate had little effect on the corrosion response.

In the current study, for finding the optimum GAS process conditions, the liquid-phase volume expansion and process conditions were evaluated for the binary [carbon dioxide (CO2)-dimethyl sulfoxide (DMSO)] and ternary [CO2-DMSO-Capecitabine (CPT)] systems, respectively. To this end, CO2, DMSO, and CPT were considered as the anti-solvent gas, organic solvent, and solute, respectively. The minimum GAS operational pressure (Pmin) for precipitation of CPT nanoparticles in the (CO2-DMSO-CPT) system was calculated by Peng-Robinson (PR-EoS) and Soave-Redlich Kowang (SRK-EoS) with conventional quadratic mixing rules (vdW2). The obtained Pmin values according to PR-EoS and SRK-EoS at 308, 318, 328 and 338 K were 7.80, 8.57, 9.78 and 10.46 MPa, and 7.27, 7.61, 7.95 and 8.13 MPa, respectively. Also, the mole fraction of CO2, DMSO and CPT in the liquid phase was determined at mentioned temperatures, using PR-EoS. For validation of these models, the Pmin values for the [CO2-DMSO-Ampicillin (AMP)] system was calculated at 308, 318, 328 and 338 K by both of models (PR-EoS and SRK-EoS) and compared with obtained results by Ghoreishi et al. for this ternary system. The computed Pmin values for precipitation of AMP nanoparticles in the (CO2-DMSO-AMP) system in this work were well in agreement with reported values in the literature.

The breakthrough of clean and efficient shale gas stimulation technology and reduction of global carbon emissions is in a critical period. The injection of supercritical carbon dioxide (SCCO2) into...

A deep understanding of the gasification behavior of porous char particle is the premise of the reactor-scale modeling, but there are few studies on the gasification characteristics in supercritical water. Thus, a numerical model for porous char particle gasification in supercritical water was developed in this work, and the effects of particle size, inflow temperature and inflow velocity were studied. Simulation results showed that gasification of the small particle of 0.1 mm lay in zone I regime where the particle radius kept unchanged due to uniform reactions inside the particle and the effectiveness factor increased rapidly after the gasification began due to easy accessibility of supercritical water into the particle. The gasification of the large particle of 1 mm showed typical characteristics in zone II regime that the particle began to shrink at a certain conversion degree, and smaller effectiveness factor was observed due to larger supercritical water concentration gradient inside the particle. As the increase of temperature and particle size, ambient fluid became difficult to flow through the unreacted core, and the Stefan flow was observed to obviously modify the hydrodynamic boundary layer at low Reynolds number. Besides, it is unreasonable to assume isothermal particle for gasification with large particle and high temperature because of the significantly overestimated particle consumption rate.

This paper used a supercritical CO2 batch foaming process to treat a waste SP double-base propellant, which is a type of double-base propellants containing 58.6% nitrocellulose, 40.0% nitroglycerin, 0.8% centralite, and 0.5% vaseline, to solve a problem of poor stability of industrial explosives directly prepared by the propellant. Experiments show that this process can produce dense pores inside the SP double-base propellant. With the increase of the pressure of supercritical CO2, the number of pores inside the foamed SP double-base propellant increased, and these pores served as hotspots in the detonation reaction. An increased number of hotspots improved the detonation stability of the perfusion explosive. During the explosion, the energy of the perfusion explosive with the foamed SP double-base propellant was released more completely, so the shock wave energy and bubble energy of the explosive gradually increased with the increase of pressure. Therefore, the supercritical CO2 foaming process can promote the treatment technology of waste double-base propellants and can optimize the detonation performance of perfusion explosives by increasing the pressure of supercritical CO2.

Supercritical CO2 fracturing is a novel hydro-free fracturing technology, which has the characteristics of minor damage to reservoirs and higher efficiency. During the process of fracturing, the CO...

Accidental release of pressurized CO2 pipeline in carbon capture and storage involves the interaction of phase change and heavy-gas dispersion. However, the effect of the phase change of water vapor in air on the performance of cold CO2 dispersion is usually neglected. In this study, a three-dimensional two-phase computational fluid dynamics (CFD) model is developed to evaluate the cold CO2 dispersion by considering the phase change of water. A phase-change model based on the homogeneous relaxation model is used to describe the evaporation and condensation of water. The effects of terrain roughness, atmospheric stability, and turbulence models on the dispersion are also considered. The numerical results show that the model that uses the k–ω turbulent equations is superior to the other models. The results in which the phase change of water is considered exhibit a better agreement with the data from the experiments than those that do not consider it. The model is subsequently used in urban areas, which results in over-predicted CO2 concentration in the near field and under-predicted CO2 concentration in the far field when the phase change of water vapor is considered than that when it is neglected. Therefore, we proposed that the phase change of water vapor in the atmosphere should not be overlooked in the more accurate modeling of cold CO2 dispersion.

In this study, an in-depth analysis has been performed on various technoengineering aspects of hydrocarbon cracking under supercritical conditions toward developing an endothermic fuel. The paper is segregated into several sections with specific emphasis. The major areas covered in this work include physicochemical characteristics of different endothermic fuels, supercritical pyrolysis of hydrocarbon fuels, phenomena of coking, and its suppression from an application viewpoint. The influence of various parameters (e.g., temperature, pressure, catalysts, space–time, etc.) on fuel conversion, endothermicity, and coke propensity has been emphasized in detail. The typical value of endothermic heat sink capacity for different fuels consisting of C8 to C15 hydrocarbons ranges from 500 to 1150 kJ/kg over temperature and pressure ranges of 550–750 °C and 25–55 bar, respectively. The effectiveness of various additives/initiators in improving endothermicity has been screened for wide ranges of temperature and pressure. Physicochemical properties like distillation characteristics, hydrocarbon composition, °API gravity, and sulfur content of different hydrocarbon fuels are compared in a single window. Most of the findings are abridged meticulously with relevant tables and plots. Toward the end, we have highlighted the critical issues/challenges on the experimental findings and prospective.

This study was aimed at evaluating the effects of exposure time and SO2 as one of the impurities on the corrosion behavior of steel pipeline transporting supercritical CO2 during carbon capture and...

This work investigates the oxidation of a nickel-based superalloy, namely Alloy X, in water at elevated temperatures: subcritical water at 261°C and 27 MPa, the transition between subcritical and supercritical water at 374°C and 27 MPa, and supercritical water at 380°C and 27 MPa for 100 h. The morphology of the sample surfaces were studied using scanning electron microscopy coupled with focused ion beam milling, and the surface chemistry was investigated using x-ray diffraction, Raman spectroscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy before and after exposure studies. Surfaces of all samples were identified to comprise of a ferrite spinel containing aluminum.

CO2 thickeners have the potential to be a game changer for enhanced oil recovery, carbon capture utilization and storage, and hydraulic fracturing. Thickener design is challenging due to polymers’ low solubility in supercritical CO2 (scCO2) and the difficulty of substantially increasing the viscosity of CO2. In this contribution, we present a framework to design CO2 soluble thickeners, combining calculations using a quantum mechanical solvation model with direct laboratory viscosity testing. The conductor-like polarizable continuum model for solvation free-energy calculations was used to determine functional silicone and silsesquioxane solubilities in scCO2. This method allowed for a fast and efficient identification of CO2-soluble compounds, revealing silsesquioxanes as more CO2-philic than linear polydimethylsiloxane (PDMS), the most efficient non-fluorinated thickener know to date. The rolling ball apparatus was used to measure the viscosity of scCO2 with both PDMS and silicone resins with added silica nanoparticles. Methyl silicone resins were found to be stable and fast to disperse in scCO2 while having a significant thickening effect. They have a larger effect on the solution viscosity than higher-molecular-weight PDMS and are able to thicken CO2 even at high temperatures. Silicone resins are thus shown to be promising scCO2 thickeners, exhibiting enhanced solubility and good rheological properties, while also having a moderate cost and being easily commercially attainable.

Polyethylene terephthalate (PET) foams were prepared at different saturation temperatures using two supercritical foaming methods. The average cell size, cell number density, and porosity of PET foams obtained using each foaming method were compared. The crystallinity of the PET samples after the saturation step in the two-step foaming process was measured to observe the CO2-induced crystallization. The crystallinity of PET according to the saturation temperature led to a variation in cell size in the two-step foaming. In contrast, the melting of crystals with the increase in the temperature affected the cell number density of the polymeric foam prepared by one-step foaming method. The influence of the PET crystals on the cell nucleation or cell growth in each foaming method was studied from these results.

A tight conglomerate reservoir is a kind of unconventional reservoir with strong heterogeneity, and CO2 injection is an economical and environmentally friendly method to enhance tight oil recovery. Supercritical CO2 is a very promising fluid medium for unconventional reservoir development due to its gas-liquid dual properties. In this study, the production effects of supercritical CO2 and non-supercritical CO2 in tight conglomerate reservoirs were quantitatively analyzed by huff and puff simulation experiments conducted under reservoir conditions (formation pressure 37 MPa, temperature 89 °C). Also, the influencing factors of CO2 huff and puff production, including injection volume, soaking time, and throughput cycles, were investigated. The results showed that supercritical CO2 improves the recovery by 4.02% compared with non-supercritical CO2. It could be seen that supercritical CO2 plays a positive role in improving tight conglomerate reservoirs. The optimal injection volume, soaking time, and throughput cycles were determined to be 0.50 PV, 2 h, and 3 cycles, respectively. This paper provides an important basis for the study of supercritical CO2 production in tight conglomerate reservoirs.

The minimum fluidization velocity of a supercritical water fluidization bed reactor (SCWFBR) is numerically nvestigated based on coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) simulations. The accuracy of the CFD-DEM model is firstly validated via previously published experimental data. Then, the model is adopted to study the effects of particle size distributions (PSD) on the minimum fluidization velocity in which four types of PSD including Gaussian-type, Mono-type, Flat-type and Binary-type are considered. Numerical results show that the minimum fluidization velocity for the Flat-type PSD is the smallest among the four while the one for the Mono-type PSD is the largest. The minimum fluidization velocities for the Mono-type and Gaussian-type PSD share quite similar values. However, it is conditionally valid when the largest amount of particle size in the Gaussian-type PSD is equal to its mean particle size which is used in the Mono-type PSD. The agreement of the minimum fluidization velocity between Mono-type and Gaussian-type PSD is also influenced by the number of small particles. The mechanism behind these phenomena is revealed by investigating the micro-structure of differently sized particles. Finally, predictive correlations for the minimum fluidization velocity of the SCWFBR are proposed based on the numerical results which demonstrates strong predictive capability for wide PSD.

The oxides formed on T12 ferritic steel surface after exposure to 560 °C/25 MPa supercritical water with dissolved oxygen contents of 300 ppb was characterised by various techniques. It was found t...

Microencapsulation is an effective method to incorporate environmentally sensitive bioactive compounds into small capsules to increase stability and bioavailability. The morphological properties, m...

The supercritical water fluidized bed (SCWFB) is a recently introduced reactor for biomass gasification that does not release pollutants. Four groups of Geldart B-type quartz sands with different particle sizes were fluidized at a system pressure of 20–27 MPa and system temperature of 410–570 °C. A series of experiments were performed for determining the drag coefficient and volume fraction of bubbles. The effects of the particles’ size, superficial velocity, system pressure, and temperature on the drag coefficient and volume fraction are discussed. In addition, a correlation between experimental and computed values is demonstrated for both the drag coefficient and volume fraction in SCWFBs. The relative error of the correlation is within ±30%. The results of this study provide significant guidance for the scaling-up design of SCWFBs and for the development of supercritical water gasification technology.

The topochemistry of Japanese beech (Fagus crenata) wood delignification was evaluated in this study following a supercritical methanol treatment (270 °C, 27 MPa). Ultraviolet microscopic analysis of the insoluble residue revealed that the lignin in the secondary wall was easily decomposed and removed because of the preferential cleavage of ether-type linkages. In contrast, the middle lamella lignin was initially resistant to supercritical methanol but eventually decomposed and was removed. In addition, UV-absorbing secondary products formed selectively inside the parenchyma cells. Results from the supercritical methanol treatment of demineralized beech wood indicated that inorganic substances in the lumen of parenchyma affected the formation of these secondary products, thus leading to an overestimation of the residual lignin. Therefore, the topochemistry of delignification was more precisely evaluated when using demineralized beech wood.

A kinetic study of the simultaneous supercritical transesterification and partial hydrogenation (SSTPH) process using soybean oil with Pd/Al2O3 catalyst was conducted. In addition, process design and economic analysis were conducted to investigate the profitability of three different continuous biodiesel production processes, each with a production capacity of 40,000 tonnes/h, including a conventional supercritical process, SSTPH process using Cu catalyst, and SSTPH process using Pd/Al2O3 catalyst. The contents of methyl oleate in the biodiesel products from the three processes were 22.9, 56.9, and 77.9 wt%, respectively. It was found that the total manufacturing costs for the SSTPH processes were higher than that of the conventional supercritical process due to partial hydrogenation. However, the total capital investment for the SSTPH process with Pd/Al2O3 was the lowest owing to the mild reaction condition. Overall, the SSTPH process using Pd/Al2O3 was the most economically feasible. Sensitivity analysis of the net present values (NPVs) was conducted according to the material prices and the plant capacity. The results of the sensitivity analysis show that the NPVs for the three processes are most sensitive to the biodiesel price. Consequently, the SSTPH process with Pd/Al2O3 had the lowest break-even biodiesel price despite the same price of biodiesel.

The present study aimed to numerically simulate the rapid expansion of the supercritical solution (RESS) process including particle generation, hydrodynamics, and solving the population balance equation (PBE) to predict the particle-size distribution (PSD) of solid-supercritical carbon dioxide binary systems. Energy, momentum, and mass equations, in addition to the extended generalized Bender equation of state (EoS), were applied to predict the hydrodynamic behavior of a supercritical solution under several operating conditions using a nozzle and expansion vessel. The tetraphenylporphyrin (TBTPP) solubility in supercritical carbon dioxide was calculated using the Peng–Robinson EoS/Kwak–Mansoori as a mixing rule. Subsequently, TBTPP, aspirin, ibuprofen, and salicylic acid nucleation as well as the supersaturation rate were calculated. Finally, we solved the time dependence of the parameters of the size distribution numerically. The established models are compared over a wide parameter range using a reference model that refers to the method of moment log-normal size distribution functions through the RESS process to predict a solid PSD. The results obtained are presented with and without coagulation phenomena. The average absolute percent deviation of solubility of TBTPP was 3.98, and the hydrodynamic behavior of supercritical carbon dioxide showed a similar trend as the results presented in the published research work. Furthermore, a particle size distribution prediction using coagulation showed acceptable agreement with the experimental PSDs.

Recent studies have shown that rutin (Quercetin-3-O-rhamnosylglucoside) may have an inhibitory effect on COVID-19. Rutin can be extracted from Tartary buckwheat as an active pharmaceutical ingredient. Nevertheless, its purification is mainly hindered by Kaempferol-3-O-rutinoside (K3R) due to their similar molecular structures. This study intends to propose a simulated moving bed (SMB) chromatography process of rutin and K3R to achieve continuous production. True moving bed (TMB) and SMB models were established to numerically analyze and optimize this process. The system consists of a four-zone SMB with two columns in each zone. The effects of the switch interval, feed flowrate, desorbent flowrate, extract flowrate, raffinate flowrate, and recycle flowrate on the purity and yield of rutin and K3R were investigated and the optimized conditions were chosen as 5 min, 3.5, 40, 34, 9.5, and 24.5 L/min, respectively. Consequently, the purities of 99.64% and 99.25%, and the yields of 99.81% and 99.37% for rutin and K3R were obtained, respectively. The simulation results can provide a guidance for the future industrial application of SF-SMB to separate rutin and K3R.

Cannabidiol (CBD) is one of the medicinal bioactive products obtained specifically from the genus Cannabis called phytocannabinoids. Among the technologies used to obtain phytocannabinoids, extraction with supercritical carbon dioxide (scCO2) has been highlighted in the literature. Thus, the knowledge of the CBD solubility limits in scCO2 in different operating conditions favors the various applications of supercritical technology to produce products with high purity of phytocannabinoids. Two studies reporting experimental measures of CBD solubility in scCO2 using different methodologies have been described in the literature. The objective of this work is to review the main results presented in these two studies, as well as to detail the differences between the applied methodologies. In addition to the experimental data on solubility, both works presented mathematical modeling based on the cubic equation of state of Peng-Robinson and the quadratic mixing rule of Van der Waals. Some thermodynamic properties of CBD were obtained from thermogravimetric analysis and differential scanning calorimetry, as well as estimated by Group Contribution Methods. The differences observed in the experimental results may be associated with the limitation of each method and/or even the enantiomeric characteristic of the CBD not previously evaluated. Therefore, it is concluded that more experiments using both methods are necessary to better define the conditions of the high solubility of CBD in scCO2.

Copolymers of poly(pentyl acrylate-co-methyl methacrylate) [P(PA-co-MMA)] were manufactured by using carbon dioxide with dispersion polymerization. The thermophysical characteristics of P(PA-co-MMA) were researched with three kinds ratios (1:20, 1:25, and 1:30) of PA vs. MMA and AIBN concentrations of (1.0, 2.0, and 4.0) wt%. Experimental product source at pressures of p ≤ 206 MPa and temperature of T ≤ 434 K was investigated for two- and three-components solution of P(PA-co-MMA) under compressed CO2, CHClF2, CHF3 and CH2F2. Experiments are carried out to get phase separation measurement for the two-component solution of P(PA-co-MMA) [1:25 mole ratio, AIBN of (1.0, 2.0 and 4.0 wt%] + compressed fluorine solvents (CHF3, CHClF2and CH2F2) solutions at a pressure of p

The interactions between CO2 and coals during CO2-ECBM (CO2 sequestration in deep coal seams with enhanced coal-bed methane recovery) could change pore morphology and chemistry property of coals, thereby affecting adsorption, diffusion and flow capability of CO2 and CH4 within coal reservoirs. To simulate CO2-ECBM process more practically, the dynamic interactions of supercritical CO2 (scCO2) and moisture-equilibrated coals were performed at temperature of 318.15 K, pressure of 12.00 MPa, and duration of 12.00 h. The impacts of the interactions on physicochemical properties of coals were investigated. Results indicate that scCO2/H2O exposure shows minor effect on micropores of coals. However, the exposure significantly decreases the mesopore surface area of bituminous coals, while increases that of anthracites. The mesopore volume and the average mesopore diameter of all the coals after scCO2/H2O exposure decrease. The multi-fractal analysis verifies that the scCO2 exposure can enhance the pore connectivity of various rank coals. Apart from the pore morphology, the exposure of scCO2/H2O also affects the oxygenic functional groups on coal surface. Particularly, the exposure of scCO2/H2O reduces the content of C O and C O of coals. The content of COOH of low rank coals including Hehua-M2# coal, Zhongqiang-4# coal, Buliangou-9# coal and Tashan-5# coal decreases, while the high rank Laochang-11# coal and Kaiyuan-9# coal witness a growth in COOH. The content of total oxygenic functional groups of all coals after interaction with scCO2/H2O decreases; on the contrary, that of C C/C H of all coals after scCO2/H2O exposure increases. In summary, the interaction with scCO2/H2O significantly changes the pore system and oxygenic functional groups of various rank coals, which needs further attention regarding CO2-ECBM.

Optical resolution by diastereomeric salt formation based on gas antisolvent fractionation is influenced by the chemical equilibrium of the salt formation, the solubility, and the extraction of the compounds. Selectivity, also known as resolution efficiency, is highly solvent-dependent and is also affected by process parameters both in atmospheric and supercritical processes. For the first time in the literature, a mathematical model that employs all three Hansen parameters and operating parameters is constructed to describe the selectivity of a gas antisolvent fractionation process. The satisfying goodness of fit of the models suggests that the outcome of the three subprocesses in the gas antisolvent fractionation process (i.e., salt formation reaction, precipitation, and extraction) can be described in a single model. A new formula for pressure and temperature correction of the hydrogen-bonding component of the Hansen parameter for non-ambient conditions for liquid methanol, ethanol, and n-propanol is also suggested in this paper.