Intensification Of Separation Research Articles

Exploration of environmentally friendly processes for converting CO2 into propanol through direct hydrogenation

This study firstly explores six process configurations for the conversion of CO2 to propanol via direct hydrogenation. The variations in the proposed configurations lie in the technologies used for off-gas treatment (such as pressure swing adsorption, oxyfuel combustion, autothermal reforming, and chemical absorption) and the intensification of separation (including the incorporation of the hydration reaction of ethylene oxide) within the process. Energy efficiency analysis, techno-economic analysis (in minimum required selling price, MRSP), and life cycle assessment (on global warming potential, GWP) were conducted to evaluate all proposed schemes. Overall, this study suggests that enhancing the selectivity towards propanol and implementing a suitable off-gas treatment strategy are crucial for this process. Based on the findings, we recommend Scheme 4, which involves auto-thermal reforming for off-gas treatment, as the optimal configuration. It leads to an energy efficiency of 45.33 %. Despite the higher MRSP (3.12 USD/kg when using grey H2, 7.45 USD/kg when using green H2, commercial process: 1.4 to 1.6 USD/kg), it significantly reduces GWP (3.19 kg-CO2-eq/kg when using grey H2, 1.59 kg-CO2-eq/kg when using green H2) created from the conventional process (6.77 kg-CO2-eq/kg). Given appropriate economic incentives, the proposed process could serve as a more environmentally friendly option for propanol production.

Recent Advances in the Selective Transport and Recovery of Metal Ions using Polymer Inclusion Membranes

AbstractPolymer inclusion membranes (PIMs) have gained significant attention in the field of metal separation and recovery due to their high selectivity, long service life, high stability, flexible design and low cost. Over the past 10 years, interest around PIMs has increased considerably; hence, the number of research papers has grown exponentially. This review provides the preparation methods and composition of PIMs, presents an overview of studies on PIMs reported since 2012, and discusses the relationship between the physicochemical properties of different types of membrane components and the microstructure, selectivity, transport performance and stability of prepared PIMs. This review also elucidates the metal transport mechanism at the interface and interior of PIMs and summarizes the modification and separation intensification methods of PIMs. Additionally, the structure and stability of PIM relative to other liquid membranes are also discussed. Finally, the existing challenges and perspectives of PIMs in the field of metal separation and recovery are proposed and highlighted. Notably, the need for highly selective and low‐cost carriers, a deeper understanding of membrane microstructure and separation mechanisms, and strategies for promoting widespread adoption of polymer inclusion membrane‐electrodialysis technology deserve particular consideration, which are of guiding significance for accelerating the industrialization process of PIMs.

Numerical and Experimental Study on the Colliding Flow Pulp Conditioning for the Separation Intensification of Unburned Carbon from Coal Gasification Slag

As a byproduct of the coal gasification process, a large amount of coal gasification slag is generated. The failure to fully dispose of it has caused the occupation of land resources and environmental pollution. Before its comprehensive utilization, the carbon and ash constituents must be separated, for which flotation is an effective method. However, the small difference in surface hydrophobicity of them cannot result in a high-efficiency separation. Therefore, a colliding flow pulp conditioning device (CFPCD) was proposed in this work to improve the interaction between the collector droplets and fine particles, and strengthen the modification of collector on the particle surface by generating a properly constructed turbulent flow field. Computational fluid dynamics (CFD) was employed to simulate the internal flow field of CFPCD to obtain the critical flow field parameters, such as the velocity, strain rate, turbulent kinetic energy, turbulent dissipation rate, and turbulent eddy scale. Additionally, particle wrap angle measurements and flotation tests were conducted to verify the performance of pulp conditioning. The results showed that a velocity gradient was obvious in the inner cylinder colliding flow area, thereby inducing the large strain rate and the intense turbulence, which were responsible for the pulp homogenization and the enhanced particle-collector interaction. With the feeding velocity increased, the fluid shear was larger and the improved performance was more obvious. According to the flotation results, the maximum recovery of unburned carbon was obtained with the feeding velocity equal to 2.5 m/s, which was consistent with the tendency of wrap angle. Meanwhile, the loss on ignition of the tailings reached the optimal value, corresponding to 9.94%.

The performance evaluation of Alamine336 in solvent extraction and polymer inclusion membrane methods for valuable ions extraction: A case study of Te(IV) separation intensification

In this research, extraction of Te(IV) from chloride solution was studied using Alamine336 extractant. In the solvent extraction experiments, Response Surface Methodology was employed to evaluate the effect of operating parameters on the extraction and stripping of Te(IV). According to results, two models were proposed for Te(IV) extraction and stripping. The ANOVA study verified the ability of the presented models to predict the experimental results. under the optimum operating parameters (Alamine336 concentration of 0.03 mol L−1, feed solution acidity of 2.36 mol L−1, temperature of 25°C, initial Te(IV) concentration of 210 mg L−1 and stripping phase pH of 8.5), Te(IV) extraction and stripping efficiency were 99.05% and 79.32%, respectively.In the polymer inclusion membrane (PIM) experiments, maximum transport of Te(IV) ions (64.58%) was achieved for membrane containing 40 wt.% Alamine336, initial acid concentration of 4 mol L−1, and receiving phase pH of 8.5.Under the optimum conditions, the extraction of Te(IV) from anodic copper sludge leach solution was 62.16% and 55.56% using the SX and the PIM processes, respectively. However, the PIM method had a higher selectivity towards Te(IV) ions.

Experimental and numerical studies of separation intensification in segmented flow microreactors

Process intensification studies have already been well-established in continuous operations, particularly achieved by using microreactors. Separation intensification benefits from the application of process intensification and shows great potential, yet it is still not sufficiently studied. In this work, liquid-liquid two-phase segmented flow capillary microreactors and simulation models based on finite element method were used to perform experimental and numerical studies on the extractive separation intensification of the Zn-Cd-Mn system, respectively. The influence of hydrodynamics including metal ion concentration, plug velocity, and initial pH of the aqueous phase on the separation factor was explored. By regulating the hydrodynamic conditions, higher separation factors are obtained in shorter times to achieve separation intensification. The Damkhler number (Da) was introduced to clarify the rate-determining step and elaborate the separation mechanism. During the simulations, the results obtained from the model based on the finite element method agree well with the experimental ones. Taking advantage of the strong complementarity between numerical and experimental studies, separation intensification can be more deeply understood.

Microwave-induced spray evaporation process for separation intensification of azeotropic system

The microwave-induced film evaporation process has recently been reported as a promising method for separation intensification of polar/nonpolar mixtures. However, the relatively low separation efficiency and evaporation amount caused by massive intermolecular heat transfer with limited evaporation area restrict its industrial application. To this end, an innovative microwave-induced spray evaporator was developed to overcome the current defects. Furthermore, the experiments demonstrated an excellent separation efficiency of alcohol-water azeotropic systems are achieved via microwave-induced spray evaporator (such as the relative volatility of EtOH was more doubled). Moreover, the experiments of several mixtures with different permittivity and dielectric loss were performed to elucidate the mechanism of microwave-induced relative volatility change (MIRVC). The experimental results revealed that the increase of high dielectric loss components in the vapor phase under microwave heating in comparative experiments verifies the inference that dielectric loss determines the direction of MIRVC.

Study of the Influence of Coalescence Baffle Inclination Angle on the Intensity of Water-Oil Emulsion Separation in a Separator Section

A study is made of water-oil emulsion separation in a separator section having a baffle with variable inclination angle for intensification of the separation process. Calculations are performed based on 2-D geometry in a rectangular area corresponding to the longitudinal section of the separator. The study revealed that for emulsion separation intensification the optimum baffle inclination angle α = 65°.

Feasibility study of CO2/N2 separation intensification on supported ionic liquid membranes by commonly used impregnation methods

AbstractThis work presents the experimental research on feasible intensification of CO2/N2 separation by utilization of the developed supported ionic liquid membranes (SILMs). SILMs were developed through specific impregnation of commercially available ceramic microfiltration/ultrafiltration membranes made by INOPOR and polydimethylsiloxane (PDMS) membranes made by Pervatech BV with chosen imidazolium based ionic liquids (ILs). The effects of operating parameters, impregnation method, and SILM thickness were analyzed.The impregnation was performed by coating and soaking methods at normal pressure and under vacuum. The proper impregnation of the ceramic support, especially in case of commercial PDMS membranes, allows to achieve two distinct, stable, highly selective separation layers. The comparison of separation efficiency of the investigated SILMs shows that SILM based on PDMS membrane prepared by coating with 1‐ethyl‐3‐methylimidazolium acetate ([Emim][Ac]) has very good stability, high CO2/N2 ideal separation factor of 152 and permeability of 2400 barrer. It was found that optimum operating conditions were feed temperature of 20°C and pressure below 200 kPa.The obtained results represent an interesting low cost alternative in the gas separation, especially when the choice of selectivity is the first priority. The comparison with literature data and upper bond Robeson correlation (2008) suggests, that applying an additional active separating IL layer and an appropriate impregnating method to the commercial ceramic membranes may result in significant improvement of separation efficiency. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.

Substantiation of the Lattice Ripper Parameters of the Carrot Digger in Conditions of the Republic of Uzbekistan

The authors showed that during carrot harvesting by diggers, strong soil lumps were formed that were poorly separated from root crops and complicated the separation process, which leaded to machines overloading, due to the variability of the physical and mechanical soil properties. A lattice loosening working body was developed that improved the digger elevator separating ability.(Research purpose)To substantiate lattice ripper parameters of the carrot digger, which provides intensive loosening of the soil and thereby increases the impurities separation completeness with minimal root crops damage.(Materials and methods)The authors researched geometric, kinematic parameters of lattice ripper of the carrot digger. They theoretically substantiated the design parameters of the mechanism and its kinematic parameters after they studied the physicomechanical properties of the carrot bed.(Results and discussion)The authors found that during the interaction of the lattice ripper with soil layers on the elevator, soil lumps were destroyed, the soil was loosened with the following parameters: the ripper radius was not more than 9.5 centimeters, the height of the shaft was 20 centimeters, the blade submerged part was 6 centimeters, the width of the lattice ripper was 47 centimeters.(Conclusions)It was revealed that lattice ripper promoted intensive separation of the soil layer without damage and loss of carrot root crops. The authors proved that the peripheral speed of the lattice ripper should be no more than 2.5 meters per second, the kinematic mode of the separation intensification means should be 2.5, and the radius of the ripper should be no more than 9.5 centimeters.

Enabling separation intensification of a lanthanide pair with closely similar kinetics based on droplet microfluidics: hydrodynamic and kinetic approaches

Separation intensification of a lanthanide pair obtained through hydrodynamic and kinetic approaches in microfluidics.

New Gasoline Absorption–Stabilization Process for Separation Intensification and Flowsheet Simplification in Refineries

A new gasoline absorption–stabilization process (GASP) is presented to intensify the separation process and significantly simplify the conventional GASP flowsheet. The conventional GASP includes four columns and recycling streams between refinery units, which makes the process very complex. In this study, the solubility and volatility of the C5–C11 hydrocarbons are discussed and a new indicator is presented to represent the performance of supplementary absorbent streams. The best suitable components are then found. A new flash tank is introduced into the GASP to obtain the suitable absorbent components to intensify the absorption process. As a result, the original secondary absorption column and the large recycling streams between the units are canceled. The conventional and new GASPs are simulated and optimized, respectively. Heat exchanger networks are designed for the two processes. The new process can significantly reduce the total annual cost by 11.24% as opposed to the conventional process.

Toward a mechanistic understanding of microfluidic droplet-based extraction and separation of lanthanides

Droplet-based microfluidic extraction is a promising way for effective lanthanides extraction due to its outstanding mass transfer performance. The separation process can be greatly enhanced with the droplet-based microfluidic extraction technique. However, the interactions between mass transfer, microfluidic dynamics and extraction kinetics are still unclear, which has hindered further manipulation on microfluidic extraction to boost extraction performance. In this study, the mechanisms of microfluidic droplet-based extraction and separation intensification of lanthanides are for the first time unveiled by using a numerical simulation model. The limiting factors for the performance of droplet-based microfluidic extraction are identified through a model-based parametric analysis. The numerical analyses provide a comprehensive understanding of droplet-based microfluidic extraction systems and offer operation and optimization guidelines for future research in this area.

Kinetics-Controlled Separation Intensification for Cesium and Rubidium Isolation from Salt Lake Brine

The separation efficiency of cesium (Cs(I)) and rubidium (Rb(I)) from a synthetic brine solution containing potassium (K(I)) was improved via a kinetics-controlled strategy. Specifically, 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) dodecane solution was partially saponified by NaOH solution first and then was directly used in extraction without adjusting the pH of the feed solution to exceed 13. Compared to the traditional process, much higher separation factors of Cs(I) and Rb(I) over K(I) (βCs/K = 1550.7, βRb/K = 45.2) were gained due to the enhanced kinetics differences during ion exchanges. In addition, the consumption of NaOH was reduced by 70–97%, and a large amount of strong alkaline wastewater was avoided because of the recyclability of NaOH saponifying agent. For synthetic brine solution containing high concentration K(I), 99.1% Cs(I) and 86.5% Rb(I) were recovered after three-stage extraction. The novel process showed a bright prospect for the extraction of Cs(I) and Rb(I).

Intensification of separation of oil-in-water emulsions using polysulfonamide membranes modified with low-pressure radiofrequency plasma

Effect of low-pressure radiofrequency capacitively-coupled plasma parameters on the separation of model “oil-in-water” emulsions using UPM-20 polysulfonamide membranes with a pore size of 0.01 μm has been studied. Atmospheric air has been used as a plasma gas. The plasma treatment time is 1, 5, 4, and 7 min at a plasma torch anode voltage of U a = 1.5–7.5 kV. The separated medium is a 3% emulsion based on the industrial oil I-20A; the stabilizer is the surfactant Kosintol-242. The highest performance is observed in the case of membranes treated with plasma for 7 min. It is found that plasma treatment leads to an increase in the emulsion separation efficiency from 90 to 99%. It has been shown that the plasma treatment contributes to the surface hydrophilization of the membranes owing to the formation of oxygen-containing functional groups. The membrane exhibits a contact angle of water of α = 59.6° before treatment and α = 19.5° after a 4-min plasma treatment at U a = 7.5 kV. Atomic force microscopy reveals that the plasma treatment leads to a change in the surface structure of the membranes, namely, to a decrease in their roughness. The internal structure of the membranes also undergoes changes which result in an increase in their crystallinity.

Industrial case study on alkaloids purification by pH-zone refining centrifugal partition chromatography

The industrial potential of pH-zone refining centrifugal partition chromatography has been evaluated by studying the purification of pharmaceutical ingredients at the pilot scale. For the first time, a scale up methodology based on both column capacity and mass transfer efficiency as invariants was developed. The purification of catharanthine and vindoline from an industrial crude extract of aerial parts of Catharanthus roseus, was used as a case of study. Toluene/CH3CN/water (4/1/5, v/v/v) was selected as biphasic solvent system, triethylamine as retainer in the organic stationary phase and sulphuric acid as displacer in the aqueous mobile phase. The separation intensification was performed on a 36mL CPC column equipped with 832 partition twin-cells. The combined effects of four parameters (displacer and retainer concentrations for intensive parameters, flow rate and rotational speed for extensive parameters) were studied by design of experiment in order to maximize both recoveries and productivities. Then, scale change was done on two larger columns (305mL and 1950mL of capacity) equipped with only 231 and 238 partition cells. For this step, it has been shown that the global mass transfer coefficient k0a (the efficiency of a column design) and the stationary phase retention (the capacity of the column) were relevant and useful scale up invariants.A CPC model based on acid-base equilibriums and interfacial mass transfer in continuously stirred tank reactors in series was used to predict fully separations on larger CPC column at the optimized operating conditions and to guide the CPC user in its scale-up strategy. The experimental validation on pilot CPC column, by injecting up to 150g of Catharanthus roseus crude extract on the 1950mL column highlighted the preservation of the separation quality, the non-linear character of the scale up in centrifugal partition chromatography and that a productivity of about 4kg of processed crude extract per day can be reached by implementing developed methodology.

Development of Spreadable Halva Fortified with Soy Flour and Optimization of Formulation Using Mixture Design

AbstractA novel spread based on sesame paste fortified with soy flour was developed. A mixture experimental design was used to investigate effect of soy flour and mono‐ and diglycerides addition on the emulsion stability (ES), color, textural properties and sensory attributes of the spreadable halva and to optimize the formulation. The ES of all samples increased as a function of the emulsifier amount. The increase of temperature led to emulsion instability and oil separation intensification. Addition of soy flour had no significant effect on hardness and adhesiveness of different halva samples (P > 0.05). There was no significant difference in color parameters (L*, a* and b*) of most halva samples (P > 0.05). Halva samples received scores of 4–7 in all evaluated attributes, and no significant difference was detected among most halva samples in all sensory properties. The range of optimum combination was determined by superimposing the contour plots of the responses.Practical ApplicationsConvenience of food consumption is an important factor in product design and development. Using a spreadable food is more favored than the molded ones. Development of spreadable halva can solve difficulty with consumption of molded halva. In addition, spreads are an excellent carrier for nutraceutical components such as soy flour. Spreadable halva can be considered as a carrier of soy flour in order to develop a novel food.

Cold model test and industrial applications of high geometrical area packings for separation intensification

With a particular focus on the separation intensification of distillation and adsorption columns, this paper reports the hydrodynamic and mass transfer performance of four novel packings, characterized by wave-like corrugation angles, and specific geometric areas ranging up to 2000 m 2/m 3. The relation between specific geometrical area, pressure drop, capacity and separation efficiency are discussed as a function of gas and liquid loads. As expected with increasing specific geometrical area the efficiency increases significantly, however, this occurs at the cost of a corresponding decrease in capacity. The expected efficiency advantage could be exploited for separations intensification in pressure drop insensitive applications, as evidenced by the presented industrial examples of applications of the packings for distillation and stripping.

Effect of ultrasound on the kinetics of extraction of the polymer component from a porous composite material

It was experimentally demonstrated that the kinetic nonequivalence of particles of low-density polyethylene (LDPE) gel which appear under the effect of a solvent in different microvolumes of the pore space of a new generation of synthetic leather (SL) base is caused by the difference in their polymer contents. It was shown that excitation of ultrasound vibrations in a solvent with a frequency of 18 kHz can reduce the duration of extraction of LDPE from the SL base as a consequence of intensification of separation of macromolecules from the surface of the gel and due to an increase in the area of this surface as a result of its fragmentation. It was hypothesized that very efficient extraction of LDPE from a SL base can also be created with the traditional method of conducting it in a large volume of extractant with an appropriate design solution of the problem of delivering the US vibrations to the treated material.