scholarly journals Treatment of oil and heavy metal contaminated water

2019 ◽  
pp. 83-88
Author(s):  
Bengt Sahlin ◽  
Sune Berg ◽  
K. Hakan Anderberg ◽  
Fredrik Tengstrom
Keyword(s):  
Environmental Management System ◽  
Spare Parts ◽  
Point Of View ◽  
Process Water ◽  
Low Flow ◽  
Modular System ◽  
Contaminated Water ◽  
Flow Rates ◽  
Wide Range ◽  
Voluntary Certification

The presence of oil contaminated water in many industrial processes causes a need for the development of techniques to purify waste process water. Purified process water can be reused, which is an advantage from an ecological as well as a financial point of view. Reuse of process water enables a reduction in water consumption, reduces the use of chemicals and results in less water that has to be disposed of. These factors will motivate companies to invest in equipment for purification of waste process water even if the flow rates are low. TTM-produkter is a Swedish company based in Kalmar aiming at developing know-how and equipment for water treatment. The company is together with the University of Kalmar developing a modular system for purification of process- and wastewater. The system will be on a low investment level, easy to operate and therefore well suited for small and mediumsized companies. The system will be tailored for a number of defined applications, easy to install and require almost no construction work on the building. A standard installation consists of a sludge and oil separator in polyethene placed on the floor, a hydrocyclone to remove particles and two filter cartridges filled with smart/selective adsorbents. Until now about 30 installations of the system have been made in Sweden and Poland. The installations cover a wide range of different industries such as car and bus washes, car demolishing plants, laundry services and ceramic, metal and graphic workshops. The best results from an ecological as well as a financial point of view has been achieved in mediumsized operations with a low flow rate of waste process water, for example a plant where 1-5 buses are washed each day or a machine for washing spare parts at a car demolishing plant. New environmental legislation and voluntary certification in accordance with ISO 1 4001 Environmental Management System not only forces but also motivates companies to invest in systems for treatment of waste process water even if the flow rates are low.

Development of an Efficient Phase Separator for Space and Ground Applications

2016 ◽  
Author(s):  
Xiongjun Wu ◽  
Greg Loraine ◽  
Chao-Tsung Hsiao ◽  
Georges L. Chahine
Keyword(s):  
Swirling Flow ◽  
Flow Behavior ◽  
Space Station ◽  
Low Flow ◽  
Design Parameters ◽  
Two Phase ◽  
Flow Rates ◽  
Void Fractions ◽  
Wide Range ◽  
Phase Separator

The limited amount of liquids and gases that can be carried to space makes it imperative to recycle and reuse these fluids for extended human operations. During recycling processes gas and liquid phases are often intermixed. In the absence of gravity, separating gases from liquids is challenging due to the absence of buoyancy. This paper discusses a phase separator that is capable of efficiently and reliably separating gas-liquid mixtures of both high and low void fractions in a wide range of flow rates that is applicable to reduced and zero gravity environments. The phase separator consists of two concentric cylindrical chambers. The fluid introduced in the space between the two cylinders enters the inner cylinder through tangential slots and generates a high intensity swirling flow. The geometric configuration is selected to make the vortex swirl intense enough to lead to early cavitation which forms a cylindrical vaporous core at the axis even at low flow rates. Taking advantage of swirl and cavitation, the phase separator can force gas out of the liquid into the central core of the vortex even at low void fraction. Gas is extracted from one end of the cylinder axial region and liquid is extracted from the other end. The phase separator has successfully demonstrated its capability to reduce mixture void fractions down to 10−8 and to accommodate incoming mixture gas volume fractions as high as 35% in both earth and reduced gravity flight tests. The phase separator is on track to be tested by NASA on the International Space Station (ISS). Additionally, the phase separator design exhibits excellent scalability. Phase separators of different dimensions, with inlet liquid flow rates that range from a couple of GPMs to a few tens of GPMs, have been built and tested successfully in the presence and absence of the gravity. Extensive ground experiments have been conducted to study the effects of main design parameters on the performance of the phase separator, such as the length and diameter of the inner cylinder; the size, location, and layout of injection slots and exit orifices, etc., on the swirling flow behavior, and on the gas extraction performance. In parallel, numerical simulations, utilizing a two-phase Navier-Stokes flow solver coupled with bubble dynamics, have been conducted extensively to facilitate the development of the phase separator. These simulations have enabled us to better understand the physics behind the phase separation and provided guideline for system parts optimization. This paper describes our efforts in developing the passive phase separator for both space and ground applications.

scholarly journals The impact of fresh gas flow on wash-in, wash-out time and gas consumption for sevoflurane and desflurane, comparing two anaesthesia machines, a test-lung study.

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1997 ◽  
Author(s):  
Fredrik Leijonhufvud ◽  
Fredrik Jöneby ◽  
Jan G. Jakobsson
Keyword(s):  
Gas Flow ◽  
Anaesthetic Agent ◽  
Point Of View ◽  
Low Flow ◽  
Test Lung ◽  
Minimal Alveolar Concentration ◽  
Flow Rates ◽  
Optimal Flow ◽  
Gas Consumption ◽  
The Impact

Low-flow anaesthesia is considered beneficial for the patient and the environment, and it is cost reducing due to reduced anaesthetic gas consumption. An initial high-flow to saturate the circle system ( wash-in) is desirable from a clinical point of view. We measured the wash-in and wash-out times (time to saturate and to eliminate the anaesthetic agent, AA), for sevoflurane and desflurane, in a test-lung with fixed 3 MAC vaporizer setting at different fresh gas flow (FGF) and calculated the consumption of AA. We tried to find an optimal flow rate for speed and gas consumption, comparing two anaesthesia machines (AMs): Aisys and Flow-i. Time to reach 1 minimal alveolar concentration (MAC) (wash-in) decreased (p<0.05) at higher flow rates (1 – 2 – 4) but plateaued at 4-4.8 l/min. The consumption of AA was at its lowest around 4-4.8 l/min (optimal flow) for all but the Aisys /desflurane group. Wash-out times decreased as FGF increased, until reaching plateau at FGF of 4-6 l/min. Aisys had generally shorter wash-in times at flow rates < 4 l/min as well as lower consumption of AA. At higher flow rates there were little difference between the AMs. The “optimal FGF” for wash-out, elimination of gas from the test-lung and circle system, plateaued with no increase in speed beyond 6 l/min. A fresh gas flow of 4 l/min. seems “optimal” taking speed to reach a 1 MAC ET and gas consumption into account during wash-in with a fixed 3 MAC vaporizer setting, and increasing fresh gas flow beyond 6 l/min does not seem to confirm major benefit during wash-out.

scholarly journals Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1684
Author(s):  
Carmelina Rossano ◽  
Claudio Luigi Pizzo ◽  
Riccardo Tesser ◽  
Martino Di Serio ◽  
Vincenzo Russo
Keyword(s):  
Levulinic Acid ◽  
Separation Efficiency ◽  
Fixed Bed ◽  
Value Added ◽  
Low Flow ◽  
Esterification Reaction ◽  
Flow Rates ◽  
Ethyl Levulinate ◽  
Wide Range ◽  
Chromatographic Reactor

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final conversion and separation efficiency of the system. The effects were described qualitatively, demonstrating that working at sufficiently low flow rates, LA was completely converted, while at moderate flow rates, only a partial conversion was achieved. The system worked properly even at room temperature (303 K), where LA was completely converted, an encouraging result as esterification reactions are normally performed at higher temperatures.

scholarly journals Investigations of wall effect on permeability through porous media at low flow rates

2017 ◽  
Vol 18 (1) ◽  
pp. 233-239 ◽  
Author(s):  
Rajat Kango ◽  
M. A. Alam ◽  
Vijay Shankar
Keyword(s):  
Point Of View ◽  
Wall Effect ◽  
Low Flow ◽  
Pressure Measurements ◽  
Relative Resistance ◽  
Seepage Velocity ◽  
Flow Rates ◽  
Bed Materials ◽  
Constant Head ◽  
Fluid Characteristics

Abstract The study of percolation of fluids through permeable subsoil strata has always been a subject of great significance from engineering point of view. The permeability depends upon both material properties and fluid characteristics. Previous studies are concentrated on the influence of regularly shaped particles on permeability, whereas the present study aims to analyse its variation due to natural randomly shaped particles. Seepage velocity of the fluid and hydraulic gradient of the soil bed materials are evaluated with the help of discharge and pressure measurements in a constant head permeameter. Specific gravity tests are conducted on different materials in order to calculate their porosities. The dependence of permeability on Dp/dg (i.e. ratio of permeameter size (Dp) to particle size (dg)) for various wall effect conditions is analysed through standard experimental procedures. The present study examines the effect of relative resistance of permeameter wall (i.e. the ratio of permeability of confined to unconfined bed) on Dp/dg. The results reveal that the aquifer confinement i.e. the distance up to which the region of randomly packing occurs directly influences the measure of permeability at lower values of Dp/dg. This effect decreases with increasing values of Dp/dg and becomes negligible at values 120 and above.

A Study of Optimum Conditions for Electrospinning Cellulose Acetate Nanofibers in Trifluoroacetic Acid Solvent

2013 ◽  
Vol 750-752 ◽  
pp. 323-327
Author(s):  
Edison Omollo ◽  
Chu Yang Zhang ◽  
Wan Jun Liu ◽  
Ncube Sizo
Keyword(s):  
Cellulose Acetate ◽  
Flow Rate ◽  
Trifluoroacetic Acid ◽  
Low Flow ◽  
Optimum Conditions ◽  
Flow Rates ◽  
Medium Voltage ◽  
Wide Range ◽  
Viscous Solution

Cellulose acetate (CA) nanofibers were electrospun in trifluoroacetic acid (TFA) under various conditions of concentration, voltage and dope flow rate while tip to collector distance (TCD) kept constant. Results showed that concentrations lower than 8 wt. % could only be electrospun at low flow rates. Bead free fibers were easily electrospun from higher CA concentrations 13 wt. % to 15 wt. %. Concentrations greater than 15 wt. % formed a viscous solution that could not be uniformly dispersed, thus impeding electrospinning. Medium voltage 20KV was found to produce good fibers while flow rates of 0.5ml/h and above, produced non-uniform fibers with a wide range. Average fiber diameters of 104nm and 129nm were formed at 13 wt. % and 15 wt. % (0.4ml/h, 20KV) respectively.

Myocardial contractile function during postischemic low-flow reperfusion: critical thresholds of NADH and O2 delivery

2004 ◽  
Vol 286 (1) ◽  
pp. H375-H380 ◽  
Author(s):  
Jason D. Stoner ◽  
Mark G. Angelos ◽  
Thomas L. Clanton
Keyword(s):  
Contractile Function ◽  
Left Ventricular ◽  
Global Ischemia ◽  
Low Flow ◽  
Critical Threshold ◽  
Rate Pressure Product ◽  
Short Term ◽  
Flow Rates ◽  
Nadh Fluorescence ◽  
Wide Range

The degree of myocardial oxygen delivery (Do2) that is necessary to reestablish functional contractile activity after short-term global ischemia in heart is not known. To determine the relationship between Do2 and recovery of contractile and metabolic functions, we used tissue NADH fluorometric changes to characterize adequacy of reperfusion flow. Isolated perfused rat hearts were subjected to global ischemia and were reperfused at variable flow rates that ranged from 1 to 100% of baseline flow. Myocardial function and tissue NADH changes were continuously measured. NADH fluorescence rapidly increased and plateaued during ischemia. A strong inverse logarithmic correlation between NADH fluorescence and reperfusion Do2 was demonstrated ( r = –0.952). Left ventricular function (rate-pressure product) was inversely related to NADH fluorescence at reperfusion flows from 25 to 100% of baseline ( r = –0.922) but not at lower reperfusion flow levels. An apparent reperfusion threshold of 25% of baseline Do2 was necessary to resume contractile function. At very low reperfusion flows (1% of baseline), another threshold flow was identified at which NADH levels increased beyond that observed during global ischemia (3.4 ± 3.0%, means ± SE, n = 9), which suggests further reduction of the cellular redox state. This NADH increase at 1% of baseline reperfusion flow was blocked by removing glucose from the perfusate. NADH fluorescence is a sensitive indicator of myocardial cellular oxygen utilization over a wide range of reperfusion Do2 values. Although oxygen is utilized at very low flow rates, as indicated by changes in NADH, a critical threshold of ∼25% of baseline Ḋo2 is necessary to restore contractile function after short-term global ischemia.

scholarly journals Simulation of Flow in Turbopump Vaneless and Vaned Diffusers with Fluid Injection

2000 ◽  
Vol 6 (1) ◽  
pp. 57-65
Author(s):  
Ali Ogut ◽  
Diego Garcia Pastor
Keyword(s):  
Flow Separation ◽  
Flow Region ◽  
Design Flow ◽  
Low Flow ◽  
Fluid Injection ◽  
Bottom Surface ◽  
Suction Surface ◽  
Vaned Diffuser ◽  
Flow Rates ◽  
Wide Range

In future space missions by NASA there will be a need for “Space Transfer Vehicles” to perform varying orbital transfers and descents. This requires engines capable of producing different levels of thrust. To accomplish this, the turbopumps employed in these engines should efficiently provide a wide range of flow outputs. However, current fuel and oxidizer turbopumps with vaned diffusers do not perform efficiently at off-design (low) flow rates mainly due to flow separation in the vaned diffuser.This paper evaluates the effectiveness of boundary layer control by fluid injection (blowing) for suppressing or eliminating the flow separation in a vaned diffuser. A 3-D flow model including vaneless and vaned diffusers of a liquid hydrogen (LH2) turbopump is studied using the CFD code FIDAP. The paper presents the results of the model at design and offdesign flow conditions.The model results showed that flow separation occurs at the top or suction surface of the vaneless diffuser and at the bottom or pressure surface of the vaned diffuser at off-design flow rates. When fluid injection was applied through the bottom surface of the vaned diffuser, the separated flow region was reduced almost entirely, resulting in an increase in pressure recovery of up to 21% with varying fluid injection rates. Results also showed that there is an optimum injection rate which is most effective in reducing or eliminating the region of flow separation.

scholarly journals The impact of fresh gas flow on wash-in, wash-out time and gas consumption for sevoflurane and desflurane, comparing two anaesthesia machines, a test-lung study.

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1997 ◽  
Author(s):  
Fredrik Leijonhufvud ◽  
Fredrik Jöneby ◽  
Jan G. Jakobsson
Keyword(s):  
Gas Flow ◽  
Anaesthetic Agent ◽  
Point Of View ◽  
Low Flow ◽  
Test Lung ◽  
Minimal Alveolar Concentration ◽  
Flow Rates ◽  
Optimal Flow ◽  
Gas Consumption ◽  
The Impact

Low-flow anaesthesia is considered beneficial for the patient and the environment, and it is cost reducing due to reduced anaesthetic gas consumption. An initial high-flow to saturate the circle system (wash-in) is desirable from a clinical point of view. We measured the wash-in and wash-out times (time to saturate and to eliminate the anaesthetic agent, AA), for sevoflurane and desflurane, in a test-lung with fixed 3 MAC vaporizer setting at different fresh gas flow (FGF) and calculated the consumption of AA. We tried to find an optimal flow rate for speed and gas consumption, comparing two anaesthesia machines (AMs): Aisys and Flow-i. Time to reach 1 minimal alveolar concentration (MAC) (wash-in) decreased (p<0.05) at higher flow rates (1 – 2 – 4) but plateaued at 4-4.8 l/min. The consumption of AA was at its lowest around 4-4.8 l/min (optimal flow) for all but the Aisys /desflurane group. Wash-out times decreased as FGF increased, until reaching plateau at FGF of 4-6 l/min. Aisys had generally shorter wash-in times at flow rates < 4 l/min as well as lower consumption of AA. At higher flow rates there were little difference between the AMs. The “optimal FGF” for wash-out, elimination of gas from the test-lung and circle system, plateaued with no increase in speed beyond 6 l/min. A fresh gas flow of 4 l/min. seems “optimal” taking speed to reach a 1 MAC ET and gas consumption into account during wash-in with a fixed 3 MAC vaporizer setting, and increasing fresh gas flow beyond 6 l/min does not seem to confirm major benefit during wash-out

scholarly journals Experimental Study on Hydroelectric Energy Harvester Based on a Hybrid Qiqi and Turbine Structure

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7601
Author(s):  
Bin Bao ◽  
Quan Wang ◽  
Yufei Wu ◽  
Pengda Li
Keyword(s):  
Energy Harvesting ◽  
Flow Velocity ◽  
Water Flow ◽  
Energy Harvester ◽  
Hybrid Structure ◽  
High Flow ◽  
Low Flow ◽  
Flow Rates ◽  
Hydroelectric Energy ◽  
Wide Range

The Qiqi structure design can automatically upset and spill its content once it arrives at limit capacity under vertical water flow excitation. Considering this function, the Qiqi structure has been utilized for small hydroelectric energy harvesting lately. To investigate the tradeoff between the Qiqi structure and the turbine structure for small hydroelectric energy harvesting, an energy harvester based on a hybrid Qiqi and turbine structure is proposed for vertical water flow hydroelectric applications. The hybrid structure is composed of a rectangular Qiqi structure, with two blades inserted on both sides. Self-tipping function of the hybrid Qiqi structure and working principle of the structure is investigated in detail. The proposed structure has both the advantages of low flow velocity energy harvesting of the Qiqi structure and high flow velocity energy harvesting of the turbine structure. A hydroelectric energy harvesting application using the hybrid structure is given to demonstrate that the hybrid structure had a higher rotational speed than the Qiqi structure under vertical low water flow excitation and was able to work at relatively high flow rates. Thus, the investigated hybrid structure can help small rotational hydropower achieve better energy harvesting performance and work at wide-range flow rates under vertical ultra-low water flow applications. At 600 mL/min, 902 μJ of electrical energy was charged by the investigated structure, which is six times higher than that using the Qiqi structure alone.

Air handling characteristics of five membrane oxygenators

Perfusion ◽  
1994 ◽  
Vol 9 (5) ◽  
pp. 357-362 ◽  
Author(s):  
AP Mehra ◽  
A. Akins ◽  
A. Maisuria ◽  
BE Glenville
Keyword(s):  
Flow Rate ◽  
Venous Drainage ◽  
Clinical Situation ◽  
Low Flow ◽  
Time Interval ◽  
Arterial Line ◽  
Flow Rates ◽  
Handling Characteristics ◽  
Wide Range ◽  
Membrane Oxygenators

This project looked at the potential of five different membrane oxygenators to allow passage of catastrophic quantities of air in a clinically simulated environment. All the oxygenators were set up in an identical circuit using heparinized human blood as the perfusate. The study was carried out at flow rates ranging from 1.0 to 6.0 I/min. The clinical situation of obstructed venous drainage was simulated by clamping the venous return line at each respective flow rate, while the initial level of blood in the open system hard shell venous reservoir was maintained at 600 ml. The time interval between the application of the clamp on the venous line and the first appearance of macroscopic air in the arterial line was recorded at each level of flow rate. A graph of time versus flow rate was plotted for each oxygenator type. At a flow rate of 6 I/min, the Safe II oxygenator took 20 seconds to allow passage of air after the venous line was clamped, while it took the Bentley Univox Oxygenator only 10 seconds. The Dideco oxygenator, which has a valve incorporated in its reservoir, did not, however, allow any air to be pumped forward at all. At low flow rates, some of the oxygenators offered protection against passage of air into the arterial line. Thus the Cobe oxygenator offered protection at flow rates of less than 2 I/min, the Safe II oxygenator at flow rates of up to 2.5 I/min and the Bard oxygenator at flow rates up to 3 I/min. This study has demonstrated the potential of membrane oxygenators to allow passage to clinical quantities of air into the arterial line. This study also has demonstrated that the top to bottom flow feature offers protection against passage of air at low flow rates only, while a simple valve is quite effective in preventing passage of air at a wide range of clinically relevant flow rates.

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