Solvent Flow Rate Research Articles

Oil recovery from defective coffee beans using pressurized fluid extraction followed by pyrolysis of the residual biomass: Sustainable process with zero waste

In this study, oil was extracted from various types of defective coffee beans using pressurized fluids. After extraction using solvents, the residual biomass was used as a raw material in a pyrolysis process to obtain bio-oil. Palmitic and linoleic fatty acids were the predominant components of the obtained oils. When n-propane was used for pressurized extraction, the yield of coffee bean oil and the phytosterols and tocopherol content increased. The highest levels were found in oil extracted from green coffee. Increasing the solvent flow rates improved the yield of the extracted oil, while increasing the temperature had the opposite effect. Higher temperatures and pressure resulted in higher levels of phytosterols. Low extraction temperatures resulted in an oil with a higher tocopherol content. The main product of biomass pyrolysis was a bio-oil rich in caffeine and phenolic compounds. This is an effective strategy for the clean and sustainable production of bio-oil.

Development of Glimepiride Loaded Sustained Release Microparticles Using Tubular Microreactor

Background: Glimepiride is a third-generation, oral anti-diabetic sulfonylurea drug, generally recommended for the treatment of type–II diabetes. A biocompatible polymer, Eudragit RS 100 is widely used for the preparation of targeted and time-controlled release of drugs. Glimepiride is encapsulated using Eudragit RS 100 for sustained release delivery. Objective: To develop sustained release microparticles of Glimepiride using microreactor technology to reduce the dosing frequency. Method: Microreactor precipitation method was used to develop sustained release microparticles of Glimepiride. Plackett-Burman design was employed for the optimization of all the parameters including the inner diameter of silicon tubing, the flow rate of solvent as well as antisolvent, length of tubing and concentration of polymer, etc. Microparticles prepared were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy and in vitro drug release as well as release kinetics study. Results: Placket Burman design was found to be effective for comparing more than two parameters at a time and showed the effect of parameters on design. The parameters A, B, C, D, E and J synergistically affected the encapsulation efficiency. FE-SEM demonstrated the smooth and spherical nature of particles. Fourier transformed infrared spectroscopy showed the absence of chemical interaction between polymer and drug; X-ray diffraction results showed the decrease in crystallinity of pure drug when it was transformed into encapsulated drug-loaded microparticles. The sustained drug release was observed for 12 h. Conclusion: Prepared Glimepiride loaded sustained release microparticles followed the first-order release kinetics. The developed formulation could reduce dose frequency and improve patient compliance.

Characterization of mass transfer study in a Kühni continuous extractor for rare earth processing using axial dispersion and backflow models

An experimental and modeling approach is presented to study the impact of operating parameters on mass transfer rate during reactive extraction in the Kühni continuous extractor. Three mathematical models were implemented to calculate the column's concentration profile. For case studies, D2EHPA extractant diluted in kerosene as an organic solvent and the aqueous solution containing lanthanum and cerium ions were utilized as the reactive solutions to provoke chemical reactions forcing desirable physical changes. Increasing rotation speed from 75 to 195 rpm generated the highest mass transfer and interfacial area and smaller drop sizes at all phase flow rates and ion concentrations. The results showed that axial dispersion and backflow coefficients of the dispersed phase increment as the solvent flow rate and agitation speed increase. These coefficients decrease with the increment in the aqueous flow rate. The AARE values (11–15%) in two extraction and stripping stages showed that the axial dispersion model is the most accurate among the three assessed mass transfer models. The modeling presented in this paper can be used as an engineering tool to design high performance for rare earth processing.

Extraction of Fatty Acids and Phenolics from Mastocarpus stellatus Using Pressurized Green Solvents.

Polyunsaturated fatty acids are well known for their protective properties in relation to different skin diseases. Although seaweeds possess a low lipid fraction, they could act as an alternative renewable source of polyunsaturated fatty acids whenever other valuable seaweed components are also valorized. In this study, a biorefinery process using Mastocarpus stellatus as a model seaweed was proposed. The process started with the supercritical carbon dioxide extraction of the lipid and phenolic fractions. The influence of pressure during extraction with pure supercritical CO2 was studied while operating at a selected temperature and solvent flow rate. Kinetic data obtained during the ethanol-modified supercritical CO2 extraction were fitted to the spline model. Sequential processing was proposed with (i) pure CO2 to obtain a product with 30% PUFA content and ω-3:ω-6 ratio 1:1, (ii) ethanol-modified CO2 to extract phenolics, and (iii) microwave-assisted subcritical water extraction operating under previously optimized conditions for the extraction of phenolics, carrageenan and protein fractions. The composition of the supercritical extracts showed potential for use in both dietary and topical applications in skin care products. The remaining solids are suitable for the extraction of other valuable fractions.

Extractive distillation to produce anhydrous bioethanol with choline chloride with urea (1:2) as a solvent: a comparative evaluation of the equilibrium and the rate-based models

The purification of bioethanol to achieve anhydrous purity standards requires separation processes other than conventional distillation, such as extractive distillation. Different solvents have been studied to find alternatives to ethylene glycol, which is widely used in this application. In this study, the aim is to find the column configuration that offers the minimum total annual cost (TAC), considering a more realistic modeling than the equilibrium stage approach for the extractive distillation with ChCl:Urea (1:2) under atmospheric pressure. This evaluation uses the rate-based modeling in the Aspen Plus® simulator. The equilibrium stage model results show that, for the same number of distillation stages and solvent flow rate, ChCl:Urea (1:2) offers from 27 to 43 % lower energy requirement for the extractive distillation process than ethylene glycol. In addition, for the same number of distillation stages it is required lower solvent amount of ChCl:Urea (1:2) in comparison with ethylene glycol. Considering the configurations of each mole flow evaluated of ChCl:Urea (1:2), on average, the rate-based simulation required columns with 62 % more stages and 8.4 % higher TAC than the equilibrium simulation. These results demonstrate the importance of considering mass and heat transfer effects to model the real process.

Desorption of carbon dioxide from a mixture of monoethanolamine with alcoholic solvents in a microreactor

In this work, mixtures of monoethanolamine with four different alcoholic solvents of methanol, ethanol, propanol, and butanol were used for carbon dioxide (CO2) absorption in a microreactor. These alcoholic mixtures were compared with a mixture of monoethanolamine and water, as this is one of the common solvents in this field. To this objective, the effect of three operating parameters, desorption temperature from 55 °C to 95 °C, the solvent flow rate from 1 mL/min to 5 mL/min, and solvent concentration from 10% to 50%, were investigated on the process of CO2 desorption in the microreactor. Furthermore, the amount of energy consumed per kilogram of CO2 desorption (E) by solvents including methanol, ethanol, propanol, butanol, and water was measured to determine the rate of desorption and energy consumption. The results showed that alcoholic solvents reduced E by more than one-third. This is more than water, which is most widely used solvent for monoethanolamine. Also, using a microreactor as a piece of genuine mass transfer equipment during the desorption process reduced energy consumption significantly. Finally, the results show that the lowest E was for the solvent of monoethanolamine + methanol, which under optimal conditions is 0.41 MJ per kg desorbed CO2 (MJ.kg-of-CO2−1). The values for the solvents of monoethanolamine + ethanol, monoethanolamine + propanol, monoethanolamine + butanol were 0.48, 0.55, and 1.1 MJ.kg-of-CO2−1, respectively. However, the values for the solvent of monoethanolamine + water in the microreactor were obtained at the optimum operating condition of about 1.39 MJ.kg-of-CO2−1.

Ultrasound-assisted pressurized liquid extraction of anthocyanins from Aronia melanocarpa pomace

This work aimed to investigate the optimum conditions of pressure, temperature, ultrasound intensity, solvent concentration and solvent flowrate of ultrasound-assisted pressurized liquid extraction of anthocyanins from Aronia melanocarpa pomace. The novel setup operates with an aqueous solution of citric acid as extraction solvent. The optimization was performed in order to maximize the total anthocyanins content extracted from the pomace. The optimized conditions of 70 °C, 180 bar, a solvent concentration of 1.5 % wt. citric acid, in a 200 W ultrasound bath were obtained. These conditions resulted in 88.0 % wt. extraction of anthocyanins in 45 min. A kinetic study was performed to study the influence of the temperature on the total anthocyanin yield obtained at the optimal extraction conditions.Moreover, the component stability was assessed to prove that the system could successfully operate at 80 °C. Compared to classical batch extraction using the same solvent concentration and feedstock, the total anthocyanin content of the extract was increased by 19%.

Investigating best available technique for CO2 chemical absorption: solvent selection based on empirical surrogate model and exergy loss

The carbon dioxide concentration in the atmosphere has reached extremely high levels, generating environmental concerns. Unfortunately, despite the climate change, CO2 is not included nowadays as a key environmental issue in Best Available Technique (BAT) reference documents (BREF). Industrially, the widespread industrial technology to capture CO2 is the chemical absorption using aqueous monoethanolamine (MEA) at 30%wt, which is the basis of comparison for novel alternative techniques in the literature and seems a suitable candidate to be proposed as Best Available Technique. Nevertheless, there is an intense research to find alternative solvents that decrease the energy consumption for carbon capture and many solvents are claimed in the literature to outperform MEA. A novel empirical surrogate model and exergy balances are used to confirm that MEA is still the best candidate to be proposed as Best Available Technique. The surrogate model proposed in this study properly regresses the CO2 gas liquid equilibrium data. The regressed parameters of the model are tabulated in this study for many aqueous alkanolamines and their mixtures, being the basis for computationally inexpensive chemical absorption column design. The surrogate model parameter considering the temperature is related with the chemical absorption energy and the consumed energy for solvent recovery. The obtained results show that none of the considered alkanolamine outperforms MEA in all the considered aspects, i.e. energy and solvent flowrate. MEA minimum flowrate is 15.62 mol solvent/mol gas and its heat of absorption regression parameter is − 27,745 J/mol. The proposed mathematical method is useful as a fast assessment for other novel alternatives that will be proposed in the future, providing energetically more efficient and cleaner technologies for CO2 capture.Graphic abstract

Yield and Extraction Rate Analysis of Phytochemical Compounds from Eucheuma cottonii, Ganoderma lucidum, and Gracilaria sp. using Subcritical Water Extraction

Eucheuma cottonii (E. cottonii), Ganoderma lucidum (G. lucidum), and Gracilaria sp. are plants that contain high phytochemicals, such as flavonoids, polyphenols, saponins, and tannins. In this work, the phytochemicals were obtained using the subcritical water extraction (SWE) process. The SWE method uses water as a solvent in subcritical conditions. Therefore, the SWE process is an environmentally friendly process for extraction. In order to run the SWE process optimally, measurement of the extraction rate of SWE is needed. Calculation of the extraction rate of SWE process used first and second-order models according to Lagergren equation. SWE process was started by setting temperatures from 140 to 180oC at a pressure of 7 MPa and solvent flow rate of 1 ml/min. Before starting the extraction, the raw material was loaded into the extractor. The raw materials used were E. cottonii, G. lucidum, and Gracilaria sp. The extraction process was carried out for 3 hours, and the product was collected every 30 minutes. The collected product was put into a sample bottle and dried using a freeze dryer. After that, the products obtained were balanced by an analytical scale. Based on the result, the optimum temperature for the SWE process was 180oC for E. cottonii and G. lucidum and 160oC for Gracilaria sp. The yields of the SWE process under the optimum temperature were 85.37%, 58.42%, and 75.73% for E. cottonii, G. lucidum, and Gracilaria sp, respectively. The extract contained phytochemical compounds detected by high-performance liquid chromatography analysis. The kinetics model of extraction rate for all variables exhibited a second-order kinetics model that indicated that the extraction process was influenced by more than one factor.

Electrospray ionization ion mobility spectrometer with new tristate ion gating for improved sensitivity for compounds with lower ion mobility

An electrospray is a dispersed nebula of charged droplets produced under the influence of a strong electric field. The charged droplets subsequently result in ions in the gas phase. Therefore, electrospray is a commonly used method for transferring liquids to the gas phase while ionizing its constituents at the same time. In this work, we investigate the performance of an electrospray ionization ion mobility spectrometer by varying the electric field strength in the desolvation region. In particular, we investigate a new tristate ion shutter with increased sensitivity for ions with higher molecular mass and lower ion mobility that are usually suppressed by classical Bradbury-Nielsen or Tyndall-Powell ion shutters when using short gating times as required for high resolving power. The electric field in the tristate ion shutter affects the optimal ratio of the electric field strengths in the drift and desolvation region. Furthermore, the solvent flow rate needs to be considered when setting the field strengths in the desolvation region. However, a higher electric field strength in the desolvation region affects the field at the emitter tip. For this reason, a smaller ratio of the drift field strength and the desolvation field strength is beneficial, especially since higher solvent flow rates require higher fields to initiate an electrospray. In this work, we use tetraoctylammonium bromide as an instrument standard and the fungicide metalaxyl, the herbicide isoproturon and the antibiotic cefuroxime as model compounds.

Production, Optimization and Characterization of Polylactic Acid Microparticles Using Electrospray with Porous Structure

Polymeric microparticles with controlled morphologies and sizes are being studied by researchers in many applications, such as for drug release, healthcare and cosmetics. Herein, spherical and porous polymeric microparticles of different sizes and morphologies by electrospray technique have been developed as a viable alternative. In this work, polylactic acid (PLA) microparticles with a spherical shape and porous morphology were successfully produced via an electrospray technique in a single step. Molecular interactions between the components and the effect of parameters, such as varying solvent compositions, flow rates and voltage on microparticle morphology, were investigated over the particle formation. It was observed that the type of solvents used is the most effective parameter in terms of particle morphology, size and distribution. When the optical microscopy and SEM images of the microparticles were examined, 3 wt.% PLA in dichloromethane (DCM) solution concentration with an applied voltage of 18 kV and a flow rate of 20 µL/min was found to be the optimum parameter combination to achieve the desired spherical and porous micron-size particles. The average diameter of the particles achieved was 3.01 ± 0.58 µm. DCM was found to be a more suitable solvent for obtaining microparticles compared to the other solvents used. Finally, particles that are obtained by electrospraying of PLA–DCM solution are porous and monodisperse. They might have excellent potential as a carrier of drugs to the targeted sides and can be used in different biomedical applications.

Emergent slow dynamics of collapsed polymers flowing through porous media.

Using hydrodynamic simulations, we study the single polymers flowing through model porous media (close-packed colloidal crystal). In good solvent or high flow rates, the polymer transport is similar to gel electrophoresis, with size-dependent sieving for L_{c}/L≲1 and size-independent biased reptation for L_{c}/L≳1 (L_{c} is the polymer contour length and L is the diameter of colloids forming the porous media). Importantly, in bad solvent and low flow rates, the polymers show an extra window of size-dependent velocity for 1≲L_{c}/L≲2, where the polymer transport is controlled by a globule-stretch transition at pore throats, and the transport velocity is much slower than reptation.

Effect of uncertainty in property models on the simulated performance of solvent-based CO2-capture—Study of aqueous AMP as solvent

Process modelling is invariably the basis for the quantitative design and evaluation of chemical processes in general and CO2-capture processes in particular. Several points need to be resolved in order to establish the validity and accuracy of the model. How good are the underlying data and models? Where are they weak and where are they strong? Which data are most important to develop reliable models? How accurate should the data be? How large should the design margins be? An effective way to resolve these important points is through uncertainty analysis. Understanding the validity and accuracy of a model through uncertainty analysis can be valuable for determining appropriate plant design margins. This work proposes a practical approach to first ensure that the model properly meets asymptotic limits (e.g., predicts equilibrium behavior for high kinetics or long contact times), and then to devise practical perturbation schemes for calculated properties in order to provide quantitative engineering insight into process uncertainties. Error propagation in process modelling is difficult because simply varying model parameters usually does not give meaningful answers from an engineering perspective, and therefore we have devised a practical scheme to perturb designated calculated properties. The results show that our approach to uncertainty analysis enables the design engineer to gain an intuitive understanding of how the uncertainty of the process models used for solvent-based CO2 capture affects the process performance, and is complementary to the mathematically complex methods. As an example, specific results obtained in this work are that the most important properties for operations (in particular, solvent flow rate and heat rate) are phase equilibrium and chemical kinetics, followed by packing interfacial area, This paper completes a study that was first presented at the 12th International Conference on Greenhouse Gas Control Technologies (GHGT-12), Austin, TX, October 5–9, 2014.

Excipient-Free Pure Drug Nanoparticles Fabricated by Microfluidic Hydrodynamic Focusing.

Nanoprecipitation is one of the most versatile methods to produce pure drug nanoparticles (PDNPs) owing to the ability to optimize the properties of the product. Nevertheless, nanoprecipitation may result in broad particle size distribution, low physical stability, and batch-to-batch variability. Microfluidics has emerged as a powerful tool to produce PDNPs in a simple, reproducible, and cost-effective manner with excellent control over the nanoparticle size. In this work, we designed and fabricated T- and Y-shaped Si-made microfluidic devices and used them to produce PDNPs of three kinase inhibitors of different lipophilicity and water-solubility, namely imatinib, dasatinib and tofacitinib, without the use of colloidal stabilizers. PDNPs display hydrodynamic diameter in the 90–350 nm range as measured by dynamic light scattering and a rounded shape as visualized by high-resolution scanning electron microscopy. Powder X-ray diffraction and differential scanning calorimetry confirmed that this method results in highly amorphous nanoparticles. In addition, we show that the flow rate of solvent, the anti-solvent, and the channel geometry of the device play a key role governing the nanoparticle size.

Towards Zero CO2 Emissions Fossil Fuel Power Plants

Carbon Capture and storage from fossil fuel power plants has gained the attention of scientists as an effective method to control greenhouse gas emissions. A post-combustion CO2 capture has been conducted using ASPEN Plus V10 software based on amine absorption /desorption for flue gas from natural gas combined cycle power plant. This optimization aimed to investigate the required solvent flowrate required thermal energy and the economic analysis for 90% capture rate of the CO2 in the first case and 99% in the second case. The CO2 absorption using monoethanolamine (MEA) as a solvent has been used in both processes. The obtained results showed that increasing the capture rate from 90% to 99% causes an increase in the solvent flow rate by 12%. Also, the increase in the capture rate causes an increase in the CAPEX by 6% and an increase in the OPEX by 9%. The Thermal heat duty for MEA regeneration was also increased by 10%. The obtained results showed an increase of less than 15% in most of the parameters which are feasible to capture 99% of the CO2 from NGCC with MEA at a reasonable energy cost.

Design of absorption process for CO2 capture using cyano based anion ionic liquid

Ionic liquids are regarded as potential candidate for CO2 absorption because of their tunable properties, wide liquid range, negligible vapor pressure and their high CO2 solubility. This work aimed to study the feasibility of CO2 separation from gas containing methane and carbon dioxide using a cyano based anion ionic liquid “1-hexyl-3-methylimidazolium tetracyanoborate” [hmim][TCB] as physical absorbent due to its high CO2 capacity and its low viscosity comparing to the organic solvent DEPG called Selexol. A comparative study among different proposed case studies for CO2 absorption in the both cases of solvent has been carried out to improve the performance of the separation process. Results show that for feed gas containing between 20 and 40mol.% of CO2, it is well favorable to use the IL instead of DEPG. At 5mol.% of CO2 in feed gas it was found that lower solvent flow rate is required for the absorption with [hmim][TCB] than DEPG and the solvent can be regenerated by combining both the pressure and temperature swing process.

Continuous SO2 absorption and desorption in regenerable flue gas desulfurization with ethylenediamine-phosphoric acid solution: A rate-based dynamic modeling

The amine-based flue gas desulfurization (FGD) method is a competitive and promising technique to realize SO2 removal and sulfur recycling from flue gas. To study the steady and transient state behaviors of continuous SO2 absorption and desorption processes with ethylenediamine-phosphoric acid solution, a rate-based system model including main units for regenerable FGD was developed and validated with experimental data. The influence of main operating conditions on the dynamic characteristics of technological parameters was investigated, moreover, a comprehensive analysis was performed to reveal the mechanism behind the parameter evolution. The results indicate that simulation results agree well with experimental data and the absorption efficiency, desorption efficiency, lean loading, and rich loading are correctly predicted, respectively. Both absorber and desorber are driven by transfer properties, and the latter is operated in a lean-pinch mode. Either the rich-SO2 loading or the gas-liquid equilibrium significantly affects the desorption performance, and an increase in rich-SO2 loading is beneficial to lower the reboiler heat duty. The normal desulfurization operation could be maintained during load-reduction scenario by cooperating with reasonable reduction of reboiler duty and moderate solvent flowrate. This work could provide engineering guidance to design the control system of amine-based FGD process for upscale exploration and input for a deep processing of SO2 product subsequently.

Comparison of Identified Compounds from Extracted Pelargonium Radula Leaves by Supercritical Fluid Extraction and Commercial Geranium Essential Oil

Supercritical fluid extraction (SFE) is a green technology that is convenient to extract Pelargonium radula (P. radula) leaves without leaving any negative impacts on the environment. It is an alternative approach to reduce the solvent residual problem during the extraction process. Therefore, this research was performed to compare the active ingredients extracted by SFE technique with the commercialized geranium essential oil in the market. Extraction of powdered P. radula leaves by supercritical carbon dioxide (SC-CO2) was operated at constant pressure, temperature, and solvent flowrate which were 100 bar, 40 °C, and 24 mL/min, respectively. SC- CO2 extraction on P. radula leaves result in 0.19 % of oil yield. By comparing extracted P. radula oil with the commercialized geranium essential oil, both oil consists of benzyl acetate, citronellol, geraniol, e-amyl cinnamaldehyde, isopropyl tetradecanoate, and isopropyl hexadecanoate.

Simultaneous extraction and separation of compounds from mate (Ilex paraguariensis) leaves by pressurized liquid extraction coupled with solid-phase extraction and in-line UV detection

The in-line coupling of the pressurized liquid extraction with a solid-phase adsorbent and a UV–Vis detector for the simultaneous extraction and separation of bioactive compounds from yerba mate (PLE-SPE-UV) was carried out in two stages. In the first stage, water was used as a solvent, while in the second stage, ethanol was used. For the optimization of the method, different adsorbents (Sepra C18-E, Isolute C18-EC, and Strata-X C18), temperatures (40–80 °C), solvent flow-rate (1–3 mL/min), and pH (4.0 and 8.0) were evaluated. By using a UV–Vis detector on-line, it is possible to monitor the process in real-time. The developed method allowed obtaining similar or higher recoveries of all the compounds classes than other methods, such as ultrasound-assisted extraction, stirring, maceration, and pressurized liquid extraction alone, in addition to separating them into fractions. The developed method could be used as sample preparation for the analysis of different compounds classes from mate.

A semi‐automatic solid phase extraction system based on MIL‐101(Cr) foam‐filled syringe for detection of triazines in vegetable oils

In this study, several metal-organic framework-melamine foam columns were first developed and used as a laboratory-made semi-automatic solid phase extraction packed in syringe adsorber for the extraction of six triazine herbicides from vegetable oil samples coupled to high-performance liquid chromatography-tandem mass spectrometry. The metal-organic framework-foam columns were prepared using a simple approach by embedding the solid particles in melamine foam using polyvinylidene difluoride physical encapsulation. The method was applicable to a wide variety of metal-organic framework materials, and the incorporated materials retained their unique properties. Key factors that affect the extraction efficiency, including the MIL-101(Cr) amount, sample flow rate, type and volume of the eluting solvent, and flow rate of eluting solvent, were investigated. Under optimum conditions, the proposed method exhibited low limits of detection (0.017-0.096ng/mL, S/N=3) for six triazines. The relative standard deviations calculated for all herbicides ranged from 0.2 to 14.9%. This study demonstrated that the MIL-101(Cr)-foam column can be used as a high-quality adsorption material for the detection of triazines in vegetable oils.