scholarly journals Simulation study of pressure swing adsorption to purify helium using zeolite 13X

2020 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Ehsan Javadi Shokroo ◽  
Mehdi Farniaei ◽  
Mehdi Baghbani
Keyword(s):  
Flow Rate ◽  
Pressure Swing Adsorption ◽  
Gaseous Mixture ◽  
Operating Conditions ◽  
Feed Flow Rate ◽  
Zeolite 13X ◽  
Adsorption Step ◽  
Fully Implicit ◽  
Wide Range ◽  
Pressure Swing

A two-bed pressure swing adsorption system on a commercial type of zeolite 13X adsorbent has been studied numerically over a wide range of operating conditions to helium separation from gaseous mixture. The model includes energy, mass and momentum balances. The coupled partial differential equations are solved using fully implicit forth order Rung-Kutta scheme in the simulation. The effects of adsorption step pressure, adsorption step time and feed flow rate on the helium purity and recovery were investigated. Results shown that as the adsorption step pressure increases the helium purity will be increased. In addition, the helium recovery increases, and the helium purity decreases when the feed flow rate increases. Finally, the simulation results indicated a very good agreement with some current literature experimental work.

scholarly journals Simulation Study of Pressure Swing Adsorption to Purify Helium Using Zeolite 13X

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ehsan Javadi Shokroo ◽  
Mehdi Farniaei ◽  
Mehdi Baghbani
Keyword(s):  
Flow Rate ◽  
Pressure Swing Adsorption ◽  
Gaseous Mixture ◽  
Operating Conditions ◽  
Feed Flow Rate ◽  
Zeolite 13X ◽  
Adsorption Step ◽  
Fully Implicit ◽  
Wide Range ◽  
Pressure Swing

A two-bed pressure swing adsorption system on a commercial type of zeolite 13X adsorbent has been studied numerically over a wide range of operating conditions to helium separation from gaseous mixture. The model includes energy, mass and momentum balances. The coupled partial differential equations are solved using fully implicit forth order Rung-Kutta scheme in the simulation. The effects of adsorption step pressure, adsorption step time and feed flow rate on the helium purity and recovery were investigated. Results shown that as the adsorption step pressure increases the helium purity will be increased. In addition, the helium recovery increases, and the helium purity decreases when the feed flow rate increases. Finally, the simulation results indicated a very good agreement with some current literature experimentally work.

scholarly journals CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
K. Rambabu ◽  
L. Muruganandam ◽  
S. Velu
Keyword(s):  
Carbon Dioxide ◽  
Flow Rate ◽  
Pressure Swing Adsorption ◽  
Cfd Simulation ◽  
Separation Efficiency ◽  
Carbon Dioxide Concentration ◽  
Operating Conditions ◽  
Analytical Models ◽  
Feed Mixture ◽  
Pressure Swing

A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA) column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate.

scholarly journals Experimental Investigation and Modeling of Inertance Tubes

2005 ◽  
Vol 127 (5) ◽  
pp. 1029-1037 ◽  
Author(s):  
L. O. Schunk ◽  
G. F. Nellis ◽  
J. M. Pfotenhauer
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Acoustic Power ◽  
Operating Conditions ◽  
Thermodynamic Efficiency ◽  
Pulse Tube ◽  
Design Charts ◽  
Wide Range ◽  
Pulse Tube Refrigerators

Growing interest in larger scale pulse tubes has focused attention on optimizing their thermodynamic efficiency. For Stirling-type pulse tubes, the performance is governed by the phase difference between the pressure and mass flow, a characteristic that can be conveniently adjusted through the use of inertance tubes. In this paper we present a model in which the inertance tube is divided into a large number of increments; each increment is represented by a resistance, compliance, and inertance. This model can include local variations along the inertance tube and is capable of predicting pressure, mass flow rate, and the phase between these quantities at any location in the inertance tube as well as in the attached reservoir. The model is verified through careful comparison with those quantities that can be easily and reliably measured; these include the pressure variations along the length of the inertance tube and the mass flow rate into the reservoir. These experimental quantities are shown to be in good agreement with the model’s predictions over a wide range of operating conditions. Design charts are subsequently generated using the model and are presented for various operating conditions in order to facilitate the design of inertance tubes for pulse tube refrigerators. These design charts enable the pulse tube designer to select an inertance tube geometry that achieves a desired phase shift for a given level of acoustic power.

Subsynchronous Vibration Patterns Under Reduced Oil Supply Flow Rates

2017 ◽  
Author(s):  
B. R. Nichols ◽  
R. L. Fittro ◽  
C. P. Goyne
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Operating Conditions ◽  
System Stability ◽  
Supporting Evidence ◽  
Test Rig ◽  
Flow Rates ◽  
Oil Supply ◽  
Bending Mode ◽  
Wide Range

Many high-speed, rotating machines across a wide range of industrial applications depend on fluid film bearings to provide both static support of the rotor and to introduce stabilizing damping forces into the system through a developed hydrodynamic film wedge. Reduced oil supply flow rate to the bearings can cause cavitation, or a lack of a fully developed film layer, at the leading edge of the bearing pads. Reducing oil flow has the well-documented effects of higher bearing operating temperatures and decreased power losses due to shear forces. While machine efficiency may be improved with reduced lubricant flow, little experimental data on its effects on system stability and performance can be found in the literature. This study looks at overall system performance of a test rig operating under reduced oil supply flow rates by observing steady-state bearing performance indicators and baseline vibrational response of the shaft. The test rig used in this study was designed to be dynamically similar to a high-speed industrial compressor. It consists of a 1.55 m long, flexible rotor supported by two tilting pad bearings with a nominal diameter of 70 mm and a span of 1.2 m. The first bending mode is located at approximately 5,000 rpm. The tiling-pad bearings consist of five pads in a vintage, flooded bearing housing with a length to diameter ratio of 0.75, preload of 0.3, and a load-between-pad configuration. Tests were conducted over a number of operating speeds, ranging from 8,000 to 12,000 rpm, and bearing loads, while systematically reducing the oil supply flow rates provided to the bearings under each condition. For nearly all operating conditions, a low amplitude, broadband subsynchronous vibration pattern was observed in the frequency domain from approximately 0–75 Hz. When the test rig was operated at running speeds above its first bending mode, a distinctive subsynchronous peak emerged from the broadband pattern at approximately half of the running speed and at the first bending mode of the shaft. This vibration signature is often considered a classic sign of rotordynamic instability attributed to oil whip and shaft whirl phenomena. For low and moderate load conditions, the amplitude of this 0.5x subsynchronous peak increased with decreasing oil supply flow rate at all operating speeds. Under the high load condition, the subsynchronous peak was largely attenuated. A discussion on the possible sources of this subsynchronous vibration including self-excited instability and pad flutter forced vibration is provided with supporting evidence from thermoelastohydrodynamic (TEHD) bearing modeling results. Implications of reduced oil supply flow rate on system stability and operational limits are also discussed.

Modelling of Partially Wetting Liquid Film Using an Enhanced Thin Film Model for Aero-Engine Bearing Chamber Applications

2020 ◽  
Author(s):  
K. Singh ◽  
M. Sharabi ◽  
R. Jefferson-Loveday ◽  
S. Ambrose ◽  
C. Eastwick ◽  
...  
Keyword(s):  
Thin Film ◽  
Contact Angle ◽  
Film Thickness ◽  
Liquid Film ◽  
Flow Rate ◽  
Operating Conditions ◽  
Film Model ◽  
Thin Film Model ◽  
Wide Range ◽  
Aero Engine

Abstract In the case of aero-engine, thin lubricating film servers dual purpose of lubrication and cooling. Prediction of dry patches or lubricant starved region in bearing or bearing chambers are required for safe operation of these components. In the present work thin liquid film flow is numerically investigated using the framework of the Eulerian thin film model (ETFM) for conditions which exhibit partial wetting phenomenon. This model includes a parameter that requires adjustment to account for the dynamic contact angle. Two different experimental data sets have been used for comparisons against simulations, which cover a wide range of operating conditions including varying the flow rate, inclination angle, contact angle, and liquid-gas surface tension coefficient. A new expression for the model parameter has been proposed and calibrated based on the simulated cases. This is employed to predict film thickness on a bearing chamber which is subjected to a complex multiphase flow. From this study, it is observed that the proposed approach shows good quantitative comparisons of the film thickness of flow down an inclined plate and for the representative bearing chamber. A comparison of model predictions with and without wetting and drying capabilities is also presented on the bearing chamber for shaft speed in the range of 2,500 RPM to 10,000 RPM and flow rate in the range of 0.5 liter per minute (LPM) to 2.5 LPM.

scholarly journals Influence of the main operating parameters on the DRPSA process design based on the equilibrium theory

Adsorption ◽  
2020 ◽  
Author(s):  
Ester Rossi ◽  
Giuseppe Storti ◽  
Renato Rota
Keyword(s):  
Pressure Swing Adsorption ◽  
Degrees Of Freedom ◽  
Pressure Ratio ◽  
Complete Separation ◽  
Operating Conditions ◽  
Equilibrium Theory ◽  
Design Parameters ◽  
Reflux Ratio ◽  
Gaseous Mixtures ◽  
Pressure Swing

Abstract Among the adsorption-based separation processes for gaseous mixtures, those exploiting pressure variations, so-called Pressure Swing Adsorption (PSA) processes, are the most popular. In this work, we focus on the specific PSA configuration known as Dual Reflux-Pressure Swing Adsorption (DR-PSA) given its ability to achieve sharp separations. In the case of binary mixtures, an analytical approach based on Equilibrium Theory has been proposed to identify the operating conditions for complete separation under the assumption of linear isotherms. This same approach is not available when the separation is not complete. Accordingly, in this work we study the features of non-complete separations by solving numerically a general DR-PSA model with parameter values suitable to approach equilibrium conditions (no mass transport resistances, no axial mixing, isothermal conditions and no pressure drop), thus reproducing the analytical solution when complete separations are examined. Even for non-complete separations, triangularly shaped regions at constant purity can be identified on a plane whose axes correspond to suitable design parameters. Moreover, we found a general indication on how to select the lateral feed injection position to limit the loss in product purities when complete separation is not established, whatever is the composition of the feeding mixture. Finally, a sensitivity analysis with respect to pressure ratio, light reflux ratio and heavy product flowrate is proposed in order to assess how to recover product purities according to the specific degrees of freedom of a DR-PSA apparatus.

Activated Carbons for Ventilation Air Methane Enrichment by Vacuum Pressure Swing Adsorption

2013 ◽  
Vol 773 ◽  
pp. 907-911
Author(s):  
Shao Bo Ouyang ◽  
Shao Ping Xu ◽  
Ning Song
Keyword(s):  
Activated Carbon ◽  
Flow Rate ◽  
Gas Turbines ◽  
Pressure Swing Adsorption ◽  
Methane Concentration ◽  
Activated Carbons ◽  
Vacuum Pressure ◽  
Bet Surface Area ◽  
Vacuum Pressure Swing Adsorption ◽  
Pressure Swing

A coconut shell based activated carbon with BET surface area of 795 m2/g, micropore volume 0.37 mL/g and total pore volume 0.44 mL/g was prepared. With this activated carbon as adsorbent, the ventilation air methane (VAM) enrichment by vacuum pressure swing adsorption (VPSA) was investigated. The influence of VPSA parameters such as feed flow rate, effluent flow rate and adsorption time on the performance of the VAM enrichment were examined. The results showed the methane concentration in the simulative VA gas could be enriched by VPSA from 0.52 vol.% to 1.51 vol.% with a methane recovery of 96.3 % at 25 °C and 200 kPa. The methane concentration in effluent gas was reduced to below 200 ppm. The as-prepared activated carbon could be used in the VAM enrichment by VPSA for lean-burn gas turbines.

scholarly journals Modeling and Optimization of Carbon Dioxide Removal in Packed Bed Column Reactor

2020 ◽  
Vol 8 (3) ◽  
pp. 8-13
Author(s):  
K. Thirugnanasambandham
Keyword(s):  
Carbon Dioxide ◽  
Process Parameters ◽  
Flow Rate ◽  
Co2 Capture ◽  
Packed Bed ◽  
Operating Conditions ◽  
Feed Flow Rate ◽  
Statistical Design Of Experiments ◽  
Packed Bed Column ◽  
Column Reactor

Global warming due to greenhouse gases has become a serious global issue. Extensive efforts are being made to fighting this phenomenon through carbon capture as carbon dioxide (CO2) is its major contributor. This study focused on CO2 capture in packed bed column reactor using Poly-(D) glucosamine under the various process parameters such as temperature, feed flow rate and mass of the adsorbent. Statistical design of experiments was carried out in order to analysis the effect process parameters on the capacity of CO2 capture in packed bed column. The obtained results show that feed flow rate has the significant affect compared to others. The maximum of 956 mg of CO2 is captured under the following operating conditions; temperature of 40oC, feed flow rate of 30 ml/min and 0.25 g of the Poly-(D) glucosamine. The ability of Poly-(D) glucosamine to capture the CO2 in packed bed column is confirmed.

scholarly journals Utilization of Bottom Ash Coal and Agarwood in Waste Water Treatment in Palembang Jumputan Fabric

2021 ◽  
Vol 6 (1) ◽  
pp. 1-7
Author(s):  
Eis Sri Hartati ◽  
◽  
Muhammad Hatta Dahlan ◽  
Tuti Indah Sari
Keyword(s):  
Activated Carbon ◽  
Flow Rate ◽  
Waste Water Treatment ◽  
Bottom Ash ◽  
Liquid Waste ◽  
Oxygen Demand ◽  
Quality Standards ◽  
Operating Conditions ◽  
Feed Flow Rate ◽  
Filtration Time

Waste containing dyes causes visual pollution and increase the risk of environmental and health issue. The aim of this study was to determine the best operating conditions of jumputan liquid waste treatment using bottom ash batubara and agar wood with variations in feed flow rate (1, 2, and 3 l/min), filtration time (30, 60, 90, and 120 mins), and treatment. The results are compared with the parameters of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), and pH of clean water quality standards for jumputan industry businesses and/or activities regulated in the Governor’s of Sumatera Selatan Regulation Number 16 year 2005. The initials analysis of jumputan liquid waste before processing showed that jumputan liquid waste did not meet these quality standards, except pH and turbidity levels. In this study, jumputan liquid waste was pretreated using coal bottom ash and activated carbon, then filtered. Biodegradation of jumputan liquid waste by conventional method. The best of BOD, COD, TSS, pH, and the percentage of color rejection in the study were obtained in the treatment of jumputan liquid waste using bottom ash batubara and activated carbon at 120 minutes filtration time and a 1 l/minute feed flow rate namely BOD 5.98 mg/l, COD 15 mg/l, TSS 22.3 mg/l, pH 7.32, color 5 Pt-Co, and 0 NTU turbidity. The filtration with bottom ash coal and agar wood can removed the coloring from dyes.

scholarly journals Optimization of a Six-Step Pressure Swing Adsorption Process for Biogas Separation on a Commercial Scale

2020 ◽  
Vol 10 (14) ◽  
pp. 4692
Author(s):  
Bundit Kottititum ◽  
Thongchai Srinophakun ◽  
Niwat Phongsai ◽  
Quoc Tri Phung
Keyword(s):  
Mass Transfer ◽  
Steady State ◽  
Pressure Swing Adsorption ◽  
Operating Conditions ◽  
Optimal Conditions ◽  
Mixed Gas ◽  
Adsorption Time ◽  
The Real ◽  
Real Process ◽  
Pressure Swing

Pressure swing adsorption (PSA) appears to be an effective technology for biogas upgrading under different operating conditions with low greenhouse gas emissions. This study presents the simulation of biomethane adsorption with the adsorption bed filled with a carbon molecular sieve (CMS). A six dual-bed six-step PSA process was studied which produced a high purity of biomethane. The design of the adsorption bed was followed by the real process of which the biomethane capacity was more than 5000 Nm3/h. For the adsorbent, a CMS-3K was used, and a biomethane gas with a minimum 92% purity was produced at 6.5 bar adsorption pressure. To understand the adsorption characteristics of the CH4 and CO2 gases, the Langmuir isotherm model was used to determine the isotherm of a mixed gas containing 55% CH4 and 45% CO2. Furthermore, the experimental data from the work of Cavenati et al. were used to investigate the kinetic parameter and mass transfer coefficient. The mass transfer coefficients of two species were determined to be 0.0008 s−1 and 0.018 s−1 at 306 K for CH4 and CO2, respectively. The PSA process was then simulated with a cyclic steady state until the relative tolerance was 0.0005, which was then used to predict the CH4 and CO2 mole fraction along the adsorption bed length at a steady state. Moreover, the optimal conditions were analyzed using Aspen Adsorption to simulate various key operating parameters, such as flowrate, adsorption pressure and adsorption time. The results show a good agreement between the simulated results and the real operating data obtained from the company REBiofuel. Finally, the sensitivity analysis for the major parameters was presented. The optimal conditions were found to be an adsorption pressure of 6 bar, an adsorption time of 250 s and a purity of up to 97.92% with a flowrate reducing to 2000 Nm3/h. This study can serve as a commercial approach to reduce operating costs.

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