Centrifugal Extractor Research Articles

Digital Twin for Centrifugal Extractors Exemplified for pDNA Clarification Process after Lysis.

Plasmid DNA is an important substance for the pharmaceutical industry. A major challenge in its production is the clarification of the lysate after harvesting. In this work, a novel process for this is demonstrated in an annular centrifugal contactor (ACC) with an aqueous two-phase extraction. The ACC can increase the space-time yield of the clarification step by at least a factor of 2 compared to the horizontal continuous separator. A model for describing and predicting the conditions in the rotor is created for the ACC and calibrated with an accuracy of R 2 = 0.94, which is sufficient for prediction in process design and operation. A digital twin (DT), which determines the purity of the phases at the outlet of the ACC, is calibrated with an accuracy of 95% for the light phase and 97% for the heavy phase, which defines in manufacturing operation the safety margin for both phases below the theoretical optimal operation point. By using the DT, an additional increase in productivity of 25% can be achieved in the ACC with model-predictive control.

Mass transfer and hydrodynamic studies in a 100 μm diameter microfluidic channel in a rotated helical configuration

A simple 3D rotated microfluidic mixer design is reported with evaluation of hydrodynamic and mass transfer performance. Proposed device had a minimalistic configuration of 3 turns, rotated in x, y, and z planes. The helical mixer volume was only 3.14 μL due to usage of 100 μm dia micro bore tubing. The proposed device was different from conventional CFI and its variants. The analysis for hydrodynamic performance indicated a massive specific interfacial area, much more than for the 50 mm centrifugal extractor with the same PUREX aqueous-organic pair. Higher volumetric amass transfer coefficients were reported for the proposed device as compared to conventional mixers (impellers and Taylor-Couette mixers). Energy dissipation values were also reported to be much higher than that of a contemporary annular centrifugal extractor. Mixing-time values (tm) were estimated at least two-order lower than residence time values (τ). Proposed design complied all the four directives of the concurrent PI paradigm.

Extraction Kinetics of Pyridine, Quinoline, and Indole from the Organic Phase with Natural Deep Eutectic Solvents and Separation Study Using a Centrifugal Extractor

In this study, the kinetics of extracting pyridine, quinoline, and indole from model fuels using natural deep eutectic solvents (NaDES) composed of carboxylic acids, xylitol, and water were investigated under static conditions. This research marks the first examination of extraction kinetics in this context. The key kinetic parameters of the extraction process were identified. Notably, it was observed that the mass transfer coefficient for indole was in the range of 3.4 × 10−6 to 1.2 × 10−6, depending on NaDES. That is significantly lower, by an order of magnitude, than for pyridine and quinoline under identical experimental conditions. The study revealed that, under specific conditions, where thermodynamic equilibrium for indole cannot be reached, it becomes possible to achieve kinetic separation of the components. The presented experimental data obtained on a centrifugal extractor showed a decrease in the degree of indole extraction with increasing flow: Extraction efficiency decreased from 63% at a flow rate of 0.05 L/h to 18% at 0.8 L/h. Moreover, the research indicated that, during indole extraction, the mass transfer coefficient in a centrifugal extractor was 1.3 × 10−4, which is two orders of magnitude higher than under static conditions. The study underscores the potential utility of the proposed extraction systems based on environmentally friendly NaDES, comprised of carboxylic acids and xylitol, for the kinetic separation of various classes of heterocyclic compounds. Overall, the research provides valuable insights into the kinetics of extraction and the potential applications of ‘green’ NaDES in the separation of heterocyclic compounds from organic liquids.

TECHNOLOGICAL BASIS OF THE PROCESS OF ZIRCONIUM AND HAFNIUM SEPARATION

The paper presents the results of industrial testing of the process and equipment for the extraction separation of zirconium and hafnium in a single technological cycle with the production of high-purity nitrate compounds and pure nitric acid solutions as raw materials for the production of sodium nitrate. It is shown that the efficiency of the extraction process is determined primarily by the purity of the nitric acid solution by the content of a critical impurity – silicic acid, which causes an undesirable emulsification process and disrupts the stability of the process. Optimal conditions have been determined under which the formation of non-extractable forms of zirconium and hafnium is excluded. The replacement of pulsating columns with centrifugal extractors reduced operating costs by reducing the volume of a one-time load of a flammable extractant and its losses as a result of hydrolysis. This increased the degree of separation of zirconium and hafnium. Centrifugal extractors provided high process kinetics, reduced production areas, and increased labor productivity and product quality.

A pilot scale test study with theoretical justification of reaction mechanism for the recovery of chromium(VI) based on solvent extraction using novel centrifugal extractors

As a strategic resource and hazardous substance, the purification and recovery of chromium(VI) from the aqueous phase have attracted attention. In this study, the centrifugal extractor was used to treat the leach liquor of sodium roasting chromite on a pilot scale. The extraction performance and equilibrium distribution of chromium in countercurrent extraction were investigated. Meanwhile, the scrubbing effect of impurities was carefully studied, and the stripping and regeneration effects of the organic phase were tested. Under the selected process parameters, the pilot scale test results, including extraction efficiency of chromium, scrubbing efficiency of impurities, and regeneration performance of the organic phase, were excellent. The qualified (NH4)2Cr2O7 and Cr2O3 products were prepared using the strip liquor, and several physical properties of the products were tested. In addition, the molecular electrostatic potential surface maps, HOMO-LUMO orbitals, Fukui functions, and single point energy of the molecules involved were calculated by Quantum Chemistry. The molecular electrostatic potential analysis, frontiers molecular orbital analysis, Fukui function analysis and interaction energy analysis were applied to investigate the mechanism of separation of chromic acid from impurities in the extraction system.

Centrifugal Extraction-Assisted Fiber-Enhanced Raman Spectroscopy for Online Detection of Trace Furfural in Oil Power Equipment.

Oil-paper insulated equipment is integral in power conversion and supports low-loss electricity transport. As a characteristic byproduct of the oil-paper insulation system, the realization of efficient detection of furfural in oil is crucial to the safe operation of the power grid. We proposed a novel approach using dual-enhanced Raman spectroscopy for sensing trace liquid components. This method employs a centrifugal extractor to separate and enrich the targeted components, achieving selective enhancement. The optimal phase ratio was determined to be 30:1. A liquid-core fiber was used to optimize the laser transmission efficiency and Raman signal collection efficiency, resulting in a nonselective signal enhancement of 44.86. It also investigated the impact of intermolecular interactions on the shift of Raman spectra, identifying the reasons for the differences in Raman signals between pure furfural, furfural in oil, and furfural in water. A batch of samples with furfural dissolved in insulation oil was measured using this system and achieved a limit of detection of 0.091 mg/L. The stability of the dual-enhanced Raman platform was experimentally verified with a spectral intensity fluctuation of 0.68%. This method is fast, stable, adaptable, and suitable for the detection of a wide range of liquid ingredients.

Developing a Hydrodynamic Model for the Mixing Chamber of a Centrifugal Extractor

Developing a Hydrodynamic Model for the Mixing Chamber of a Centrifugal Extractor

Feasibility studies on the detection of third phase formation in the solvent extraction equipment during reprocessing of fast reactor spent fuels

Fast reactor spent fuel plants reprocess plutonium rich fuel discharged from fast reactors. Centrifugal extractor or mixer settler solvent extraction equipments are employed for the selective recovery of nuclear grade uranium and plutonium from fission products. 30% (v/v) TBP/NPH is used as the solvent in PUREX process. Plutonium rich spent fuel has disadvantage of third phase formation during process upsets. Third phase can leads to flooding thereby prone for nuclear criticality or explosion hazard in evaporators. Hence, the solvent extraction equipments should be continuously monitored to detect onset of third phase. Studies are carried out by placing electrical conductivity probe in the organic outlet of a single stage mixer settler. This study measured electrical conductivity in different runs. 12 M feed nitric acid run and 15.8 M nitric acid feed acidity run indicated the conductivity at organic outlet is beyond 1035 μS/cm, indicated severe flooding as well as two phases in organic collecting container. Uranous in nitric acid run indicated when the A/O change was initiated loaded organic phase (8–11 μS/cm) conductivity at organic outlet decrease to 2.06 μS/cm as well when probe inserted at the organic and aqueous interface jumped to 190 μS/by forming Third phase. The results of this study indicated it is feasible to detect online of third phase in solvent extraction equipment such as mixer settler.

Hydrodynamics Study on Annular Centrifugal Contactors: CINC V 02 as an Example

AbstractAlthough annular centrifugal extractors (ACCs) have been increasingly applied in the process industry recently, their complex fluid dynamics is still not fully explained in the literature. This could be one of the major reasons why their current industrial implementation is not up to their potential. This work aims to enhance the understanding of ACC hydrodynamics by focusing on liquid holdup and distribution in the variant CINC V 02. First, several sources causing holdup variation are investigated with the help of a model simulating the liquid surface inside the device. Then, the factors determining liquid content in both chambers are presented. The standard shut‐down procedure to measure holdup is eventually elaborated on, and an improved procedure is proposed.

Resource-saving and environmental protection in nuclear-grade zirconium and hafnium production

The development of efficient and environmentally friendly technological processes for processing zircon concentrate is an urgent problem in the technology of producing reactor-pure zirconium and hafnium used in nuclear power. The review presents the environmental, technical and economic characteristics of zircon decomposition processes using existing industrial technologies and provides data on the environmental safety of each technology. It is shown that current industrial technologies do not meet the criteria of sustainable development and allow emissions of toxic reagents into the environment. New applications of particularly pure zirconium and hafnium compounds which have emerged in recent decades, with impurity content of 10-3–10-5%, require less corrosive reagents than chlorine and fluorine, new resource-saving processes and equipment. Today, technical zirconium oxide with a purity of 98% is the main industrial product of zircon processing, but it allows for losses of hafnium, scandium and silicon. This is equivalent to financial losses of over USD 150 million per year. Based on the analysis of promising halogen-free technologies, a new integrated zircon processing technology is proposed which allows producing scarce hafnium, scandium and silicon compounds along with reactor-pure zirconium and its high-purity chemical compounds. The chemicals consumed in the zircon processing process are utilized in the production of mineral fertilizers, eliminating environmental pollution. The use of the highly efficient refining extraction process in a nitric acid environment using centrifugal extractors with an available tributilphosphate extractant allows us to obtain reactor metals with a purity of 99.95%. The production of high-purity zirconium, hafnium, scandium and silicon oxides meets the demand for non-nuclear products, which expands the volume of integrated zircon processing and meets the growing market demand for new functional materials. The integrated approach to zircon processing can reduce the cost of zircon by producing by-products, recycling consumed reagents and eliminating non-recyclable solid and liquid waste. This will ensure environmental protection even with relatively small volumes of reactor-pure metal production.

Quaternary solvent system for highly efficient separation and purification of glabridin by fractional extraction

• A quaternary solvent extraction system was explored to separate and purify glabridin. • The extraction system is green and simple without reactive extractant. • A mathematical model was established to simulate and optimize extraction process. • Residual rate is introduced to describe product purity and impurity content. • Glabridin with high purity and yield has been obtained continuously. A quaternary solvent extraction system was used to separate and purify glabridin from a crude extract of Glycyrrhiza glabra L. The influence of solvents and their ratios on the distribution of glabridin was examined to develop an efficient quaternary solvent extraction system. For the optimal solvent extraction system, the organic phase consisted of 22.64% butyl acetate, 73.80% hexane, 0.24% water and 3.30% ethanol (W/W), and the water phase consisted of 1.79% butyl acetate, 0.57% hexane, 56.09% water and 41.55% ethanol (W/W). To determine the ideal parameters for separation, a mathematical model was used to simulate and optimize the multi-stage processes. The yield and residual rate were used as the purity reference to simulate the separation of glabridin. Under the optimal conditions, two series of ten-stage and twenty-stage centrifugal extractors were successfully used to separate glabridin. The yield and purity of glabridin were 85% and 94%, respectively, after twenty-stage separation.

Extraction of scandium from sulphuric acid-based red mud leach liquors

Equimolar mixtures of di-2-ethylhexylphosphoric acid (D2EHPA) with trin-butylphosphate (TBP) or trioctylamine (TOA) in kerosene were used for extracting scandium from sulphuric acid-based red mud leach liquor. The results showed that when using a D2EHPA-TOA mixture, the overall extraction of scandium (ЕSc) tends to rise from 37 to 68% as the concentration of sulphuric acid rises. At the same time, the extraction of concomitant elements tends to decrease and remains way below the Е Sc . When using a D2EHPATBP mixture, the rising acidity of the solution does not lead to any significant increase in scandium extraction so that the latter remains quite high (i.e. 82–85%) while the extraction of the concomitant elements is significantly lower. A five-stage countercurrent extraction process was performed using a mixture of 0.1 mol/L D2EHPA and 0.1 mol/L TBP with 2 mol/L sulphuric acid to recover scandium from the liquor with minimized amounts of concomitant metals. The results showed that a 96.8% of scandium can be recovered after a three-stage countercurrent extraction process with 97% aluminium, 95% iron, 87% titanium and 54% zirconium removed from the liquor. A 4.7 mol/L sulphuric acid solution with an organic to aqueous ratio of 1:1 was used to wash the organic phase after a three-stage extraction process. For reextraction, a solution containing 2.5% NaOH and 6.5% Na2CO3 was used at a 2:1 aqueous to organic phase ratio. The solution was filtered to separate the solid phase. The precipitate was washed and dried and a primary 3.42% concentrate was obtained. Based on the obtained data, the authors describe a scandium extraction process using sulphuric acid-based red mud leach liquor. The new scandium concentration by extraction process parameters were tested on an enlarged scale at the Intermix MET site. A 100 g experimental batch of primary scandium concentrate containing, %: 2.2 Sc; 21.8 Тi; 4.3 Na; 0.6 Al; 1.7 Fe; 5.0 Zr; 0.0056 Y, was obtained from a 260-litre red mud leach liquor. For this, a cascade of five centrifugal extractors was used at the extractant saturation stage. An 8-litre mixture of 0.1 mol/L D2EHPA and 0.1 mol/L TBP in Exxsol D100 was used. The organic phase was in recycle, and due to that its saturation was 340 mg of scandium per litre of extractant.

Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

Recent progress in hydrodynamic characteristics research and application of annular centrifugal extractors

Liquid Hold-up Volume and Phase Ratio (A/O) of HNO3–DtBuCH18C6/n-Octanol System in an Annular Centrifugal Extractor

ABSTRACT The crown ether strontium extraction (CESE) process has been developed for the recovery or removal of Sr from acidic high-level liquid waste (HLLW) in China, where the extractant is 4’,4”(5”)-di-(tert-butyldicyclohexano)-18-crown-6 (DtBuCH18C6) and the diluent is n-octanol. When the CESE process was operated in annular centrifugal extractors (ACEs) for demonstration by cold and hot tests, it was found that the outlet aqueous phases had organic-phase entrainment even though ACEs operated at a low rotor speed. For the successful operation of the CESE process in ACEs, effects of the operating and geometrical parameters on the liquid hold-up volume and phase ratio (aqueous phase/organic phase, A/O) of the HNO3 –DtBuCH18C6/n-octanol system in a ϕ20 ACE were systematically investigated to find the cause of the above-mentioned hydrodynamic performance problem of the CESE process using the liquid-fast-separation method. It is shown that the operating and geometrical parameters have effects on the liquid hold-up volume and phase ratio (A/O). Moreover, the phase ratio (A/O) in the separation zone of the rotor is less than 1.5 under most of the present experimental conditions, which shows organic-phase entrainment may easily occur in the outlet aqueous phase. The cause can be that the density difference of two phases is small, viscosity of the organic phase is large, and interfacial tension of the extraction system is low.

Liquid‐Liquid Centrifugal Extractors: Types and Recent Applications – a Review

AbstractIn light of the elevating pressures toward adopting intensifying technologies, centrifugal extractors are increasingly drawing attention as a promising alternative to traditional extraction equipment. Recently, many fields have applied them in research and that resulted in a considerable amount of information that may be hard to follow. To keep interested researchers updated, this work presents the state‐of‐the‐art status of those devices. That is, the different types of centrifugal extractors are first surveyed with emphasis on those available on the market nowadays. Then, their recent applications are covered with exclusion of two fields: oil‐water separations and nuclear industry, as the purpose is to accent centrifugal extractors' potential and compatibility with the widest possible range of applications beyond traditional ones. A further section addresses the hydrodynamics of annular centrifugal contactors that form a major subfamily of centrifugal extractors. Those annular variants have received special focus throughout this work, since not only are they the most encountered devices in literature but also still to date under development with latest versions being 3D‐printed.

Techno-economic analysis of a new downstream process for the production of astaxanthin from the microalgae Haematococcus pluvialis

The biotechnological production of the carotenoid astaxanthin is done with the microalgae Haematococcus pluvialis (H. pluvialis). Under nutrient deficiency and light stress, H. pluvialis accumulates astaxanthin intracellularly and forms a resistant cyst cell wall that impedes direct astaxanthin extraction. Therefore, a complex downstream process is required, including centrifugation, mechanical cell wall disruption, drying, and supercritical extraction of astaxanthin with CO2. In this work, an alternative downstream process based on the direct extraction of astaxanthin from the algal broth into ethyl acetate using a centrifugal partition extractor (CPE) was developed. A mechanical cell wall disruption or germination of the cysts was carried out to make astaxanthin accessible to the solvent. Zoospores containing astaxanthin are released when growth conditions are applied to cyst cells, from which astaxanthin can directly be extracted into ethyl acetate. Energy-intensive unit operations such as spray-drying and extraction with supercritical CO2 can be replaced by directly extracting astaxanthin into ethyl acetate. Extraction yields of 85% were reached, and 3.5 g of oleoresin could be extracted from 7.85 g homogenised H. pluvialis biomass using a CPE unit with 244 mL column volume. A techno-economic analysis was done for a hypothetical H. pluvialis production facility with an annual biomass output of 8910 kg. Four downstream scenarios were examined, comparing the novel process of astaxanthin extraction from homogenised cyst cells and germinated zoospores via CPE extraction with the conventional industrial process using in-house or supercritical CO2 extraction via an external service provider. After 10 years of operation, the highest net present value (NPV) was determined for the CPE extraction from germinated zoospores.

Countercurrent chromatography approach to palladium and platinum separation using aqueous biphasic system

For the first time, widespread aqueous biphasic polymer-salt extraction system was applied for selective separation of Pd(II) and Pt(IV) from chloride technological solutions by countercurrent chromatography using a rotating coiled column (an analog of centrifugal extractor). The principle novelty of the proposed approach is the possibility of multistage extraction process and the needlessness to add any specific reagents for targeted metal binding. The results showed that the use of poly(ethylene glycol)-1500 (PEG-1500) as a stationary phase allows 96–100% of both Pd(II) and Pt(IV) to be recovered from chloride solutions containing copper and nickel. To obtain individual solutions of targeted metals it is enough to change the composition of the salt-rich phase for stripping stage, in particular the salt concentration and pH value. The final purity of the targeted metal fractions obtained after their extraction from model technological solutions is ≥ 99.9%. The components of the aqueous biphasic system are recyclable, non-toxic, available, and widespread in laboratory and technology practice. A scheme of the multistage separation of platinum metals using a rotating coiled column is proposed.

Pilot Plant for Studies of REE Separation by Extraction Chromatography Based on a Cascade of Centrifugal Extractors

Pilot Plant for Studies of REE Separation by Extraction Chromatography Based on a Cascade of Centrifugal Extractors

On the Operation of Centrifugal Extractors in Liquid–Liquid Chromatography Mode

On the Operation of Centrifugal Extractors in Liquid–Liquid Chromatography Mode

Lipid recovery from Nannochloropsis gaditana using the wet pathway: Investigation of the operating parameters of bead milling and centrifugal extraction

The aim of this work is to track and optimize lipid recovery from Nannochloropsis gaditana in wet extraction operations. No significant differences in biomass concentration were found when disrupting microalgal suspensions of up to 30 g/L dry weight, but disruption efficiency differed depending on their physiological states. It took 5.8 min in a bed milling device to disrupt 80% of the cells in a nitrogen-depleted culture (10–30 g/L), compared to 4.8 min for a nitrogen-replete culture (10–30 g/L). The fatty acids released were then recovered by two different methods: one using a centrifugal partition extractor device and the other using a continuous centrifugal extractor device. For the latter, Box-Behnken RSM analysis showed that the interaction between biomass concentration and solvent inlet rate had the greatest influence on lipid recovery. Up to 84% of the triacylglycerol was recovered using 7.9 g/L of algal suspension at 5.4 mL/min, and treated with 8.9 mL/min of 2-methyl-tetra-hydrofuran.