Increasing Feed Pressure Research Articles

CFD modeling of braid-reinforced hollow fiber membranes for efficient water and bovine serum albumin (BSA) separation

This study presents a comprehensive investigation into the performance optimization of a braid-reinforced hollow fiber membrane (BHFM) system for protein separation from milk wastewater. Extensive CFD simulations were conducted to examine the effects of various effective parameters on system performance. The results reveal that at a feed protein concentration of 100 mg/l, the average water flux increases from 149.16 to 453.68 l/m2.h as the inlet feed pressure rises from 100 to 300 kPa. Similarly, for a feed protein concentration of 300 mg/l, the average flux rises from 98.69 to 299.84 l/m2.h. However, higher feed concentrations lead to increased fouling and lower water fluxes. Additionally, an increase in feed pressure results in a decrease in the protein rejection rate, particularly in the initial stages of separation. The study highlights that variations in membrane porosity and thickness significantly affect both protein rejection rate and water flux. Increasing membrane porosity from 0.2 to 0.8 leads to a decrease in protein rejection rate from 94.57 % to 78.47 % at an inlet pressure of 100 kPa, and from 93.33 % to 73.43 % at 300 kPa. Similarly, increasing membrane thickness from 0.1 to 1.0 mm decreases the time-averaged water flux from 105.76 to 8.64 l/m2.h at 100 kPa, and from 321.39 to 25.99 l/m2.h at 300 kPa. However, increasing membrane thickness also increases the protein rejection rate. The study's novelty lies in the quantitative results obtained through CFD simulations, providing valuable insights into BHFM system performance. Future research should focus on exploring innovative braid architectures and material selection to enhance the mechanical stability and durability of braid-reinforced structures under various operational conditions.

CFD simulation for CO2 separation using diamond-structured thermally rearranged (TR) polymer membrane: Effect of CO2 feed concentration, feed pressure and temperature

Abstract CO2 separation in natural gas purification is important in improving the properties of natural gas such as energy content, volume and corrosivity. Membrane separation using TR-450 polymer membrane is a potential approach to remove CO2 from natural gas efficiently. The study of CO2/CH4 binary gas mixture separation was simulated using a thermally-rearranged (TR) HAB- 6FDA membrane at 450 °C with a partial part of Schwarz Diamond structure because it exhibits advanced mechanical properties with low stiffness for relatively high strength. TR-450 membrane exhibits excellent separation performance that has the potential to exceed the Robeson plot 1991. Computational fluid dynamics (CFD) was used to simulate the fluid behavior within the geometry created using CAD software. The effect of feed pressure, temperature and CO2 feed concentration on the separation performance of TR-450 membrane was also studied. The results indicated that an increase in feed pressure leads to a decrease in CO2 recovery, hence the lower separation performance. It was also found that increasing the feed temperature leads to an increase in CO2 recovery. Concerning the concentration of CO2 in the feed, elevated levels impact the performance of membrane separation. The enhanced membrane separation performance demonstrated by the TR-450 membrane under various conditions underscores the necessity for additional investigation to unveil its potential in industrial gas separation applications.

Hydraulic permeation-induced water concentration gradients in ion exchange membranes

Although substantial literature has detailed transport through swollen membranes, there are still conflicting reports regarding the fundamental physics of hydraulic water transport in such materials, with a long-standing debate centered on the applicability of the pore-flow and solution-diffusion mechanisms. The critical thermodynamic distinction between these models is the presence of a membrane-phase concentration gradient. For pure solvent transport, the pore-flow model presumes that a membrane-phase pressure gradient drives transport in the absence of a concentration gradient. In contrast, the solution-diffusion model proposes that a membrane-phase concentration gradient drives transport and that there is a negligible pressure gradient through the membrane. To address this topic for ion exchange membranes, this study reports measurements of water concentration profiles in pressurized films of Nafion and a commercial membrane based on sulfonated poly (styrene-co-divinylbenzene). Several films were stacked together in a custom-built permeation cell, with the feed side pressurized to between 68.9 and 137.9 bar, and the permeate side held at atmospheric conditions. At steady state, the experiment was stopped, the films were separated, and the water content of each film was measured, revealing a water concentration gradient through the stack thickness that increased with increasing feed pressure. The experimental data were in good agreement with theoretical predictions based on Fick's law and polymer-solvent swelling theories (i.e., Flory-Huggins and Flory-Rehner). These results are consistent with the solution-diffusion model and cannot be explained by a pore-flow mechanism.

Modeling pore wetting in direct contact membrane distillation—effect of interfacial capillary pressure

In this study, we aimed to develop a model for computing direct contact membrane distillation (DCMD) performance, taking into account capillary pressure effects at the liquid–gas interface within membrane pores. We developed a simulation model to investigate how factors such as pore radius, feed/permeate temperature, pressure, and contact angle influenced the distance of liquid intrusion into the pore, the weight flow rate in a single pore, and the temperature at the liquid–gas interface. The model predicted that the permeation rate would decrease with an increase in the feed pressure when the permeate pressure was kept constant and also when the pressure difference between the feed and permeate was kept constant. It also predicted that the permeation rate would increase with an increase in the permeate pressure when the feed pressure was kept constant. The model also indicated that partial pore wetting would be enhanced with an increase in feed pressure when the pore size was as large as 1 μm but would diminish when the pore size was as small as 0.1 μm. According to the model, partial pore wetting diminished with a decrease in the permeate pressure. The model’s predictions were in line with the trends observed in the experimental DCMD flux data by many authors, particularly those regarding the effects of feed and permeate temperature and the effect of contact angle. The model’s predictions were compared with the experimental data recorded in the literature, validating the model’s accuracy.

Development of remote-controlled solar-powered pesticide sprayer vehicle

Pest species pose a significant threat to the agricultural industry as they can negatively impact crop productivity and result in potential financial losses due to damage. This research aims to address agricultural challenges in the local area and improve the efficiency of pesticide application. A solar-powered, remote-controlled, semi-automated knapsack sprayer vehicle has been developed to address this issue. It operates using a 100 AH battery that is charged by four 30W solar panels connected in tandem to produce 120 W, providing power to the motors and pump. The vehicle uses a 12 V hub motor to drive the back and steer the front and is equipped with a 12 V window regulator/wiper motor. The vehicle is controlled by a remote control and an HC-05 transmitter and receiver, programmed with an ATMEGA32A linked to a relay board. The vehicle utilizes a 116 psi ≈ 799.8 kPa pump for the sprayer. Results indicate that as the feed pressure increases, the flow rate steadily rises and reaches 4 L per minute at the 799.8 kPa pump. With a pump spray rate of 5 L per minute when increased and a pesticide tank capacity of 20 L, the vehicle can spray for a total of 4 min and cover 159 m. Employing a remote control reduces the need for manual labour, making pesticide spraying more consistent, efficient, and productive. The sprayer also saves time compared to traditional methods and poses no harm to the operator.

Seawater desalination energy efficiency and emissions reduction at Gold Coast Desalination Plant

This paper investigates the implementation of Artificial Intelligence (AI) and Machine Learning (ML) in the operation of the Gold Coast Desalination Plant (GCDP) to optimise reverse osmosis (RO) membrane efficiency, reduce energy consumption, emissions, and operational costs. The study focuses on using historical and current RO operational data to train and utilise an AI algorithm that generates daily operational setpoints. These setpoints, namely RO Recovery (%) and Permeate Flow (m3/h), directly impact pump power consumption and energy requirements. The collaboration between Veolia and a cleantech start-up involves multiple phases, including system review, performance tests, and iterative optimisation. Three (3) performance tests were conducted at GCDP, revealing unique challenges and findings. Performance Test 1 demonstrated energy savings despite rapidly increasing cartridge filters differential pressure (dP) in the test period. Performance Test 2 encountered underperformance of an energy recovery device (ERD), resulting in increased feed pressure and with it, power consumption. Performance Test 3 highlighted the impact of fluctuating feedwater temperature on energy consumption. Overall, the AI model showcased its ability to recommend setpoints within operational limits and achieve required permeate flow with reduced energy, even under unfavourable conditions. The initiative at GCDP resulted in an estimated 1.1% energy reduction, corresponding to approximately 0.023 kWh/m3 and the potential to save up to 1044 MWh of energy and 762 tonnes of CO2-e per annum. The study suggests further exploring AI and ML applications to optimise treatment plant operations, including varying permeate flow setpoints and improving data transfer and setpoint implementation methods. These advancements hold promise for enhanced energy efficiency and cost reduction in desalination plants worldwide.

Preparation and Characterization of Polyvinylalcohol/Polysulfone Composite Membranes for Enhanced CO2/N2 Separation

The unique properties of polyvinyl alcohol (PVA) and polysulfone (PSf), such as good membrane-forming ability and adjustable structure, provide a great opportunity for CO2-separation membrane development. This work focuses on the fabrication of PVA/PSf composite membranes for CO2/N2 separations. The membranes prepared by coating a 7.5 wt% PVA on top of PSf substrate showed a relatively thin selective layer of 1.7 µm with an enhanced CO2/N2 selectivity of 78, which is a ca. 200% increase compared to the pure PSf membranes. The CO2/N2 selectivity decreases at a rapid rate with the increase of feed pressure from 1.8 to 5 bar, while the CO2 permeance shows a slight reduction, which is caused by the weakening of coupling transportation between water and CO2 molecules, as well as membrane compaction at higher pressures. Increasing operating temperature from 22 °C to 50 °C leads to a slight decrease in CO2 permeance, but a significant reduction in the CO2/N2 selectivity from 78 to 27.1. Moreover, the mass transfer coefficient of gas molecules is expected to increase at a higher velocity, which leads to the increase of CO2 permeance at higher feed flow rates. It was concluded that the CO2 separation performance of the prepared membranes was significantly dependent on the membrane operating parameters, and process design and optimization are crucial to bringing CO2-separation membranes for industrial applications in post-combustion carbon capture.

Synthesis and performance evaluation of copper and magnesium-based metal organic framework supported ionic liquid membrane for CO2/N2 separation

The CO2 emission is enhancing drastically because of the continuous emission from industries and transport sector. Although the CO2 emission had decreased in the first half of 2020 by 8.8% due to COVID-19 restrictions however, it is again on the rise and it might exceed the estimated level in 2030. The current methods used for CO2 separation have serious operational and environmental constraints. To overcome these problems we have devised a supported ionic liquid membrane (SILM) incorporated with the blend of bimetallic metal-organic framework (MOF) of copper and magnesium ions (CuxMgx) and Trihexyltetradecylphosphonium chloride [P66614] [Cl] ionic liquid (IL). CuxMgx MOF were synthesized and characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and energy dispersive X-ray analysis (EDX). CuxMgx MOF with [P66614] [Cl] IL were immobilized on a flat sheet of polytetrafluoroethylene (PTFE) membrane. Single gas permeation tests of membranes loaded with 0.2/0.8 wt/wt% MOF/IL solution showed the highest CO2 permeability of 2937 Barrer and CO2/N2 selectivity of 33.26. The performance of SILM was also investigated with different water loadings of (30 wt % and 50 wt %) in addition to MOF/IL solution and at different feed pressure varying from 0.5 to 2 bars. Membranes showed enhancement in CO2 permeability to 3738 and 4628 Barrer whereas CO2/N2 selectivity decreased to 23.53 and 21.8 with membranes loaded with 30 and 50 wt % water, respectively, at a feed pressure of 2 bar. The gas permeation results show that the incorporation of CuxMgx MOF with IL in polymeric membrane enhances the CO2/N2 separation under humid conditions but slightly decreases CO2/N2 selectivity with an increase in feed pressure. The SILM synthesized in this research is highly viable for industrial flue gases because of the incorporation of phosphonium-based ILs that have high thermal stability.

Treatment of Barbital and Triazine from the Surface Water Using a Reverse Osmosis (RO) Process Containing SW-40-HRLE-400-Polyamide Membrane

In this study, barbital and triazone samples taken from surface water located in Manisa-İzmir Turkey were treated using a RO membrane reactor process. No significant effect of feed pressure on permeate flow rate was detected. An increase in barbital and triazone concentration did not significantly vary the permeate flow rate. No significant variations of barbital and triazone rejections were detected versus feed increasing pressure at constant barbital and triazone concentrations, and no significant effects of temperature increase on the rejections of barbital and triazone were detected. The effect of increasing feed pressure did not significantly correlate with e-water recovery (rejection) from the permeate and pollutant recoveries from the retentate. The total cost was calculated as Euros 0,306 to treat 1 m3 surface water from barbital and triazone.

Delineation of the diamine monomers effect on the desalination properties of polyamide thin film composite membranes: Experimental and molecular dynamics simulation

The success of membrane desalination technology hinges on the properties of thin film composite (TFC) membrane that is commonly fabricated by interfacial polymerization (IP) of diamine and acyl chloride. The current study aimed to investigate the impact of the length of the alkyl side chain of the diamine monomers on the desalination performance of the TFC membranes. Four diamines (piperazine (PIP), 1-(2-aminoethyl)piperazine (EAP), 1,4-Bis(3-aminoprpyl)piperazine (DAPP), and m-xylylenediamine (XLN)) were used to fabricate four different TFC membranes with trimesoyl chloride (TMC) as a crosslinker. The merits of the TFC membranes were thoroughly characterized and the PIP was found to be advantageous compared to other diamines with different aliphatic alkyl chain lengths. Molecular dynamics simulations showed that PIP TFC membrane has a tight pore diameter of 1.1 nm and polar carboxylic groups within its pores, which makes it strongly hydrophilic reporting a water contact angle of 28°. The salt rejection (%) of the PIP TFC membrane followed the order: MgSO4 (91%) > Na2SO4 (85%) > Na2CO3 (77%) > NaCl (32%). The increase in feed pressure, temperature or velocity had a positive impact on the permeate flux. However, salt rejection deteriorated as the temperature of the feed increased.

Downscaling reverse osmosis for single-household wastewater reuse: towards low-cost decentralised sanitation through a batch open-loop configuration

Abstract There is a significant demand for water recycling in low-income countries. However, wastewater infrastructure is primarily decentralised, necessitating the development of affordable household-scale reclamation technology. In this study, a batch open-loop reverse osmosis (RO) system is therefore investigated as a low-cost clean water reclamation route from highly saline concentrated blackwater. In a single-stage configuration, increasing feed pressure from 10 to 30 bars improved selective separation at water recovery exceeding 85%, whereas lower cross-flow velocity improved product recovery, reducing specific permeate energy demand from 21 to 4.8 kWh m−3. Rejection achieved for total phosphorous (99%), chemical oxygen demand (COD, 96%), and final pH (8.7) of the RO permeate was compliant with the ISO30500 reuse standard for discharge. However, the rejection of total nitrogen in the RO permeate was non-compliant with the reuse standard due to the transmission of low-molecular weight (MW) uncharged organic compounds. It is suggested that rejection may be improved by increasing feed pressure to rebalance selectivity but may also be controlled by reducing fluid residence time (storage) to constrain the hydrolysis of urea. The economic analysis identified that a high-pressure 1812 element cost of ∼US$30 meets the sanitation affordability index of US$0.05 capita−1 day−1. However, the unit cost of a high-pressure feed pump must be reduced to ∼US$500 to obtain an affordable system cost. These unit costs can be achieved by manufacturing 1812 elements at economies of scale, and by adopting pumping solutions that have been developed for other applications requiring high pressures and low flows. Overall, our findings suggest that RO in the batch open-loop configuration has the potential to deliver affordable and safe water production from blackwater in a decentralised (single-household) context.

Weakly pressure-dependent molecular sieving of propylene/propane mixtures through mixed matrix membrane with ZIF-8 direct-through channels

Metal organic frameworks (MOFs) hold great potential as one of the most promising membrane materials for propylene/propane separation which is a challenging process in petrochemical industries. However, the dramatic performance decline of MOF-based membranes arising from either increased feed pressure or blended polymer limits their application. Here, we demonstrate mixed matrix membranes (MMMs) with ZIF-8 direct-through channels (DTC) can delicately solve the above two critical problems. The 6FDA-DAM polymer network surrounding ZIF-8 was speculated to restrain the linker or seal the defects between ZIF-8 crystals. Accordingly, DTC-MMMs exhibit weakly pressure-dependent separation performance. At a feed pressure of 6 bar, the separation factor decrease of DTC-MMMs is only 9.1% in comparison with 35.7, 54.1, and 52.3% from conventional mixed matrix membranes (cMMMs), 6FDA-DAM and ZIF-8, respectively. Meanwhile, the DTC-MMMs exhibit a high propylene permeability of 582 Barrer and propylene/propane separation factor of 42.8, which is respectively 8.6 and 2.1 times higher than those from the state-of-the-art cMMMs and retains nearly 70% of the ZIF-8 crystal's separation performance according to Maxwell modeling. Considering the high-pressure stability, superior separation performance, and solution-processability, we anticipate that the DTC-MMMs could pave a new avenue to the design of next-generation MMMs for diverse molecular separations. • A new class of mixed matrix membrane (MMM) with direct-through channels (DTC) is developed. • Embedded MOF crystals nearly penetrate the polymer matrix and thus dominate the separation performance. • Exceptionally high-pressure stability at 6 bar and outstanding C 3 H 6 /C 3 H 8 separation performance are achieved. • The transport mechanism is elucidated by Maxwell and in-parallel flow models.

Dynamic response and flexibility analyses of a membrane-based CO2 separation module

Renewable energy sources and fossil-fueled power plants integrated with carbon capture technologies are expected to play an important role in sustainable energy supply in the future. In this regard, this study aims to improve the flexibility of membrane-based CO2 capture units as a promising technology for CO2 capturing by analyzing the system's transient behavior. A rigorous dynamic model for a single-stage membrane separation system is developed, which includes differential equations of transport phenomena across the membrane, mass balances, and pressure distributions. The model is utilized to investigate the dynamic performance of a single-stage counter-current membrane module for separating CO2 from the flue gas of a power plant, including up to 13 vol% of carbon dioxide. Step-changes in feed pressure, feed flow rate, feed composition, and retentate recycling are considered for the analysis. The results show that by step increase in feed pressure from 5 to 8 barg, undershoot behavior is detected, and the membrane module requires about 7 s to reach a steady-state condition. In contrast, by step decrease in feed pressure, there is an overshoot, and the module requires 11 s for new steady. Also, the membrane module responds slowly to step-changes in feed composition and retentate recycling (∼20 s) compared to other step-changes in operating conditions. This paper provides new insights into the dynamics analysis of the membrane process as well as the flexible operation of membrane-based carbon capture systems.

Development of an integrating coagulation and reverse osmosis system to treat highly turbid water using synthesized coagulants.

In the present study a coagulation process was used as a pretreatment for a reverse osmosis (RO) membrane with turbid raw water collected from Bisalpur dam, Rajasthan, India. To optimize the coagulation performance, three kinds of coagulant, namely, alum (commercially available), synthesized inorganic polymeric coagulant-medium basicity (IPC-M), and inorganic polymeric coagulant-ultrahigh basicity (IPC-UH) were examined for turbidity removal with varying operating parameters. It was observed that in the optimum pH range of 6-7, the IPC-UH was the best performing coagulant with a 0.99 mg/L equivalent Al2O3 dose, revealing 2 NTU residual turbidity and residual aluminium of 0.001 mg/L. Moreover, the Langelier saturation index and Ryznar stability index values were evaluated at optimum conditions for all the three coagulants providing negligible scaling potential. Furthermore, the coagulant-treated water (100 L) was fed to the RO membrane, and the performance was noted in terms of flux, pressure, and total dissolved solids. It was observed that IPC-UH had the lowest reduction in permeate flux of 0.78 L/min/m2 compared with the commercially available coagulant alum (0.90 L/min/m2). Also, an increased feed pressure was observed for all the coagulant-treated waters with the lowest value of 2.3 kg/cm2 for IPC-UH, which was 2.5 kg/cm2 for alum (commercially available coagulant). Therefore, integration of coagulation before the RO system resulted in effective pretreatment of turbid water with very minute scaling.

Polyvinylidene Fluoride Membrane with a Polyvinylpyrrolidone Additive for Tofu Industrial Wastewater Treatment in Combination with the Coagulation-Flocculation Process.

Wastewater from the tofu industry contains many pollutants that are very harmful to the environment, significantly endangering aquatic life and producing a pungent odor. This study aims to prepare a polyvinylidene fluoride (PVDF) membrane with the additive polyvinylpyrrolidone (PVP), and utilize it to treat tofu wastewater in the ultrafiltration (UF) process. Flat sheet membranes were prepared using PVDF that was dissolved in N,N-dimethylacetamide (DMAc) and then combined with the additive material of PVP at the varying compositions of 14.9/0.1, 14.85/0.15, and 14.8/0.2 g of PVDF/gram of PVP. The addition of PVP was proposed to improve the properties of the membranes. Characterization by scanning electron microscope (SEM), water contact angle, and Fourier transform infrared spectroscopy (FTIR) were performed on the PVDF/PVP membrane flat sheet in order to understand and compare changes in the physical and chemical properties that occurred in the membrane. Prior to the UF process, the tofu wastewater was treated by a coagulation–flocculation process through a jar tester using poly aluminum chloride (PAC) as a coagulant. Based on the membrane characterization, the addition of PVP improved the physical and chemical properties of membranes. The pore size of the membrane becomes larger, which could increase permeability as well as the flux value. The TSS and turbidity of the water produced in the UF process decreased with an increase in feed pressure due to a greater driving force generated to facilitate the penetration of the suspended solids. The UF results showed that the effect of PVP on water flux was greatest for the 14.85/0.15 PVDF/PVP membrane for both pure and wastewater. In addition, the highest percentage of rejection for TSS and turbidity were observed in the 14.9/0.1 PVDF/PVP membrane and rejection for TDS was indicated in the 14.8/0.2 PVDF/PVP membrane. Meanwhile, the resulting pH decreased slightly across all samples as feed pressure increased.

Fouling and mitigation mechanisms during direct microfiltration and ultrafiltration of primary wastewater

Direct membrane filtration (DMF) has recently gained attention as an alternative secondary biological wastewater treatment process. This study evaluated direct microfiltration (MF) and ultrafiltration (UF) performance and cleaning protocols during crossflow DMF of primary municipal wastewater effluent. Several types of MF and UF membranes were examined by threshold flux determination, and two types of membranes (MF, 0.08 μm; UF, 100 kDa) were chosen for exploring membrane fouling mechanisms at different feed pressures via both fouling resistance analysis and optical coherence tomography (OCT) observation. The results revealed that both MF and UF displayed three-stage fouling behaviors, i.e., initial intermediate pore blocking followed by two-stage cake filtration. Increasing feed pressure from 8 kPa to 50 kPa could accelerate physically reversible fouling rate (consistent with simulated cake filtration constant). During physical flushing, the cake layer was more readily removed from the UF membrane; while residual porous cake layer was present on the MF membrane, regardless of the feed pressure. With extending filtration-cleaning cycle, shortening filtration duration and elevating cleaning solution temperature to from 25 °C to 50 °C benefited for irreversible fouling alleviation. At 50 °C, the geothermal water performed similar cleaning behaviors as clean water, facilitating lower reversible and irreversible fouling than the geothermal brine. This study shed light on the feasibility of using high temperature geothermal water for periodic physical cleaning during DMF of wastewater under Icelandic scenario.

Dehydration of Natural Gas Using Polyether Sulfone (PES) Membrane and Its Nanocomposite with Silica Particles and Nitrogen Sweeping Gas

Natural gas must be dehydratedbefore being sent to the distribution network to control corrosion and prevent the formation of solid hydrates. Membrane technology is a viable alternative to conventional glycol absorbents and adsorbent solids. This study was performed to evaluate the dehydration of crude natural gas by membrane separation process. Various operating conditions such as the effect of silica nanoparticles, pressure and sweeping gas on the removal of water vapor dissolved in natural gas were investigated using PES membrane and its nanocomposite. PES membranes and their nanocomposites with silica was made by solution mixing method in solvent dimethyl formamide. The properties of silica nanoparticles and fabricated nanocomposite membranes were evaluated by Fourier transfer spectroscopy and scanning electron microscopy. The dehydration rate was from natural gas in the pressure range of 2 to 10 bar and temperature of 30 °C in the presence of nitrogen sweeping gas. The addition of silica nanoparticles to the PolyetherSulfonemembrane significantly reduced the moisture content of natural gas. Also, with increasing feed pressure, the amount of water permeation from the membrane improved. The use of nitrogen sweeping gas reduced the amount of water in natural gas in pure Polyether Sulfone membranes by more than 80% and in nanocomposite membranes by more than 100%.

Experimental and theoretical studies of biopolymers on the efficient CO2/CH4 separation of thin-film Pebax®1657 membrane

Modified polymeric membranes consisting of a polyethersulfone (PES) support layer and a thin selective Pebax®1657 layer blended with biopolymers (sodium alginate and sodium carboxymethylcellulose) were developed to increase the separation efficiency of CO2 from CH4. The experimental and theoretical investigations were carried out to evaluate the influence of biopolymers loading on the gas separation performance of modified membranes. High CO2 solubility of biopolymers and their proper compatibility with Pebax®1657 were confirmed by Monte Carlo and molecular dynamics simulation, respectively. The double-layer structure of the membranes, biopolymer effect on crystalline phase, and thermal properties of the selective layer were investigated by FE-SEM, XRD, and TGA-DTG-DSC analysis, respectively. The use of alginate and carboxymethylcellulose in the Pebax layer increased CO2 permeability from about 21 Barrer to about 37 and 52 Barrer at 4 bar, respectively. In this regards, the CO2/CH4 ideal selectivity improved from 22 to 31 around and 47. Also, the gas permeability increased in all membranes by increasing feed pressure in the rage of 4-7 bar. For the alginate-modified membrane, the CO2/CH4 ideal selectivity showed an ascending trend by increasing pressure and reached 40.6 at 7 bar while the ideal selectivity of the carboxymethylcellulose-modified membrane decreased by increasing feed pressure.

Research on the features of particles passing through screen in the three products hydrocyclone screen (TPHS)

This paper aims to investigate the features of particles passing through screen in a new Three Product Hydrocyclone Screen (TPHS). The result shows that with the increasing feed concentration, particles reporting to overflow, underflow and screen underflow become coarser, finer and bigger, respectively; as the feed pressure increases, those first increases then decreases, rises and falls, respectively; with the increase of spigot size, those become coarser, bigger and stable, respectively. Further, the optimum feed concentration, feed pressure and spigot size were 120 g/l, 0.07 MPa and 17.50 mm, respectively. Moreover, as the feed concentration, feed pressure or spigot diameter increases, both the average particle size and concentration of fluid permeating screen raises, while the permeating throughput decreases as either the increasing feed concentration or the decreasing feed pressure and spigot diameter. Besides, the deeper axial depth of cylindrical screen, the less particles penetrating screen.

Research on the features of particles passing through screen in the three products hydrocyclone screen (TPHS)

This paper aims to investigate the features of particles passing through screen in a new Three Product Hydrocyclone Screen (TPHS). The result shows that with the increasing feed concentration, particles reporting to overflow, underflow and screen underflow become coarser, finer and bigger, respectively; as the feed pressure increases, those first increases then decreases, rises and falls, respectively; with the increase of spigot size, those become coarser, bigger and stable, respectively. Further, the optimum feed concentration, feed pressure and spigot size were 120 g/l, 0.07 MPa and 17.50 mm, respectively. Moreover, as the feed concentration, feed pressure or spigot diameter increases, both the average particle size and concentration of fluid permeating screen raises, while the permeating throughput decreases as either the increasing feed concentration or the decreasing feed pressure and spigot diameter. Besides, the deeper axial depth of cylindrical screen, the less particles penetrating screen.