Removal of trichloroethylene and trichloroethane using a novel hollow-fibre gas-permeable membrane

2003 ◽  
Vol 3 (5-6) ◽  
pp. 67-72
Author(s):  
S. Takizawa ◽  
T. Win
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Removal Efficiency ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Hollow Fibre ◽  
Permeation Rate ◽  
Permeable Membrane ◽  
Diffusional Boundary Layer

In order to evaluate effects of operational parameters on the removal efficiency of trichloroethylene and 1,1,1-trichloroethene from water, lab-scale experiments were conducted using a novel hollow-fibre gaspermeable membrane system, which has a very thin gas-permeable membrane held between microporous support membranes. The permeation rate of chlorinated hydrocarbons increased at higher temperature and water flow rate. On the other hand, the effects of the operational conditions in the permeate side were complex. When the permeate side was kept at low pressure without sweeping air (pervaporation), the removal efficiency of chlorinated hydrocarbon, as well as water permeation rate, was low probably due to lower level of membrane swelling on the permeate side. But when a very small amount of air was swept on the membrane (air perstripping) under a low pressure, it showed a higher efficiency than in any other conditions. Three factors affecting the permeation rate are: 1) reduction of diffusional boundary layer within the microporous support membrane, 2) air/vapour flow regime and short cutting, and 3) the extent of membrane swelling on the permeate side. A higher air flow, in general, reduces the diffusional boundary layer, but at the same time disrupts the flow regime, causes short cutting, and makes the membrane dryer. Due to these multiple effects on gas permeation, there is an optimum operational condition concerning the vacuum pressure and the air flow rate. Under the optimum operational condition, the residence time within the hollow-fibre membrane to achieve 99% removal of TCE was 5.25 minutes. The log (removal rate) was linearly correlated with the average hydraulic residence time within the membrane, and 1 mg/L of TCE can be reduced to 1 μg/L (99.9% removal).

Separation and Hydrodynamic Performance of Air-Kerosene-Water System by Bubble Column

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Abbas H. Sulaymon ◽  
Ahmed Abed Mohammed
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Bubble Column ◽  
Removal Rate ◽  
Air Flow ◽  
Bubble Diameter ◽  
Water Concentration ◽  
Hydrodynamic Performance ◽  
Air Flow Rate ◽  
Flotation Process

The separation of emulsified kerosene in water (concentration 250-750ppm) was investigated in a bubble column15.6 cm diameter and 120 cm height. The effective behaviors of bubble characteristics (bubble diameter, bubble rise velocity and air hold-up) on the removal efficiency were measured by electroresistivity probe. The effects of kerosene concentration, air flow rate,bubble diameter, liquid height, liquid viscosity, NaCl concentration, and alum on the removal rate were found. The experimental results showed that the removal efficiency increased with increasing air flow rate (1.09-2.6cm/s) and decreased with increasing CMC concentration. The results also showed that adding anionic surfactants (SLES and SDBS) leads to increase removal rate. The the flotation process was found to be first order kinetics. New correlations of air holdup and bubble diameter using dimensionless groups were derived.

Air Sparging for Mixing Non-Newtonian Slurries

2010 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Carl W. Enderlin ◽  
S. Tzemos
Keyword(s):  
Flow Regime ◽  
Flow Rate ◽  
Air Flow ◽  
Newtonian Fluids ◽  
Air Sparging ◽  
Air Bubbles ◽  
Air Flow Rate ◽  
Primary Flow ◽  
Zone Of Influence ◽  
Made In

The mechanics of air sparger systems have been primarily investigated for aqueous-based Newtonian fluids. Tilton et al. (1982) [1] describes the fluid mechanics of air sparging systems in non-Newtonian fluids as having two primary flow regions. A center region surrounding the sparger, referred to as the region of bubbles (ROB), contains upward flow due to the buoyant driving force of the rising bubbles. In an annular region, outside the ROB, referred to as the zone of influence (ZOI), the fluid flow is reversed and is opposed to the direction of bubble rise. Outside the ZOI the fluid is unaffected by the air sparger system. The flow regime in the ROB is often turbulent, and the flow regime in the ZOI is laminar; the flow regime outside the ZOI is quiescent. Tests conducted with shear thinning non-Newtonian fluid in a 34-in. diameter tank showed that the ROB forms an approximately inverted cone that is the envelop of the bubble trajectories. The depth to which the air bubbles reach below the sparger nozzle is a linear function of the air-flow rate. The recirculation time through the ZOI was found to vary proportionally with the inverse square of the sparging air-flow rate. Visual observations of the ROB were made in both water and Carbopol®. The bubbles released from the sparge tube in Carbopol® were larger than those in water.

scholarly journals Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Mehdi Amin ◽  
Mohammad Sadegh Hatamipour ◽  
Fariborz Momenbeik ◽  
Heshmatollah Nourmoradi ◽  
Marzieh Farhadkhani ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Air Flow ◽  
Sandy Soils ◽  
Air Injection ◽  
Combination Method ◽  
Soil Vapor Extraction ◽  
Air Flow Rate ◽  
Vapor Extraction ◽  
Toluene Removal

The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

Simulation on combined rapid gravity filtration and backwash models

2009 ◽  
Vol 59 (12) ◽  
pp. 2429-2435 ◽  
Author(s):  
S. J. Han ◽  
C. S. B. Fitzpatrick ◽  
A. Wetherill
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Air Flow ◽  
Experimental Results ◽  
Particle Removal ◽  
Air Flow Rate

Combined rapid gravity filtration and backwash models have been applied to simulate filtration and backwash cycles. The simulated results from the backwash model suggest that an optimum air flow rate exists to maximise particle removal efficiency in the backwash operation for a certain backwash system. The simulation of combined rapid gravity filtration and backwash models suggests that the filter shouldn't be completely cleaned up in the backwash and a certain amount of particles retained on filter grains after backwash can be beneficial for subsequent filtration runs. This is consistent with the experimental results in the literature.

Utilization of Wet Forest Biomass as both the Feedstock and Electricity Source for an Integrated Biochar Production System

2018 ◽  
Vol 34 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Anthony Eggink ◽  
Kyle Palmer ◽  
Mark Severy ◽  
Dave Carter ◽  
Arne Jacobson
Keyword(s):  
Heat Exchanger ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Integrated System ◽  
Low Flow ◽  
Production Plant ◽  
Production Operation ◽  
Air Flow Rate ◽  
Process Heat

Abstract. A belt dryer and gasifier generator set were integrated into a biochar production plant to use process heat to dry biomass feedstock from forest residuals and to provide electric power to the plant using a side stream of dried biomass. Experiments were conducted to characterize the dryer throughput and drying capacity using process heat from a stack heat exchanger attached to the biochar machine flare. A matrix of tests was conducted at high and low flow rates for both the heat exchanger air flow rate (which varied the temperature and heat input to the dryer) and the residence time of feedstock in the belt dryer. Mean feedstock input moisture during dryer characterization was 45% and the mean moisture after exiting the dryer was 27%. The optimal test condition, providing the greatest water removal rate, was determined to have high air flow rate through the heat exchanger and short dryer residence time. This condition was used to demonstrate the integrated system for an 8-h production day. The integrated system dried incoming feedstock from 36% to 22% with a dryer throughput rate of 495 kg h-1 w.b. and an evaporation rate of 88.8 kg h-1, providing the necessary dry feedstock for the 20-kW gasifier generator set and the biochar machine, which produced 75 kg h-1 of biochar. This system required the operational effort of 0.92 labor hours per production hour. Results from this demonstration indicate that the integrated system provides key benefits in a biochar production operation including greater control of feedstock drying and the ability to operate without an external (non-biomass) source of fuel for electricity generation. Keywords: Biochar, Biomass, Biomass drying, Forest residuals, Gasification, Pyrolysis.

scholarly journals EFFECT OF NAOH CONCENTRATION AND RESIDENCE TIME ON THE CONVERSION OF REMOVAL OF Ca2+ AND Mg2+ IN SEAWATER CONTINUOUSLY USING AN BAFFLED REACTOR

Konversi ◽  
2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Dita Nurmala Tristanti ◽  
Harishul Ulum ◽  
Soemargono Soemargono ◽  
Nove Kartika Erliyanti
Keyword(s):  
Residence Time ◽  
Flow Rate ◽  
Gas Flow ◽  
Air Flow ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Naoh Solution

The aims of this study were to determine the effect NaOH concentration and residence time on the conversion of calcium (Ca2+) and magnesium (Mg2+) removal as impurities. The concentration of NaOH used in this study were 0.05N, 0,1N, 0.15N, and 0,2N. The reactor used in this study is an baffled reactor equipped with air as a stirrer with air flow rates of 10000, 15000, 20000, 25000, and 30000 ml/minute. The ratio between the flow rate of seawater toward the flow rate of NaOH solution in this study was 85ml/minute : 25ml/minute.The results showed that the NaOH concentration and residence time had a significant effect on the conversion of removal of (Ca2+) and magnesium (Mg2+) impurities. The best results were obtained at 0.25N NaOH concentration, residence time of 13,08 minute, and gas flow rate of 30000ml/minute with removal conversion of calcium (Ca2+) of 73.083% and magnesium (Mg2+) of 89.621%.

Effect of Temperature and Air flow rate on Xylene Removal from Wastewater using Packed Column Air Stripper

2014 ◽  
Vol 67 (4) ◽  
Author(s):  
Hamidah Kamarden ◽  
Mohd. Ariffin Abu Hassan ◽  
Zainura Zainon Noor ◽  
RK Raja Ibrahim ◽  
Abdullahi Mohammed Evuti
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Linear Trend ◽  
Air Flow ◽  
Packed Column ◽  
Effect Of Temperature ◽  
Air Flow Rate ◽  
Column Temperature ◽  
Percentage Removal ◽  
Effects Of Temperature

In this research, the effects of temperature and air flow rate on the removal efficiency of xylene from wastewater using packed column air stripper were investigated at a temperature range of 30 to 500C and air-water ratios of 20 to 100. The quantities of xylene in effluent from the air stripper were determined using UV-visible spectrophotometer. The effects of increase in temperature on the percentage removal of xylene were found to be more significant at low temperatures (30-400C) than at higher temperatures (45-500C). Also, the effects of increase in water-air ratio on percentage removal of xylene were less significant at higher G/L ratio (80-100) and more significant at low G/L ratios (20-60), thus revealing a non-linear trend in the effect of temperature and air-water ratio on xylene removal.The result also indicates that xylene removal efficiency is greatly affected by column temperature and G/L ratio with the highest removal efficiency of 99.93 at temperature of 500C and at G/L ratio of 100.

Removal of NH3 in Air Released from Rubber Latex Process Using Skim Serum Absorbent

2013 ◽  
Vol 844 ◽  
pp. 441-444
Author(s):  
Siranat Pansang ◽  
Preecha Kasikamphaiboon ◽  
Juntima Chungsiriporn
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Pure Water ◽  
Air Flow ◽  
Liquid Waste ◽  
Industrial Scale ◽  
Water Usage ◽  
Air Flow Rate ◽  
Treatment Efficiency ◽  
Rubber Latex

The treatment of NH3 releasing concentrated rubber latex to air was studied using skim serum in laboratory scale of bubble absorption reactor. The skim serum (pH 2.5 to 3) is a liquid waste from concentrated rubber latex. The concentration of NH3 in air (300 to 1500 ppmv) and air flow rate (0.5 to 1.5 l/min) feeding into the reactor were measured for the effect of the treatment efficiency. At lower NH3 concentration and air flow rate have resulted to higher NH3 removal efficiency. Bubble absorption reactor can be effectively used and applied to remove NH3 releasing from the concentrated rubber latex process to the air without any plugging of the skim rubber in the system. Skim serum waste liquid has the result in higher efficiency in NH3 removal comparing to pure water usage. This study would be practically used as a guidance for the further design and operate to minimize waste and emission control in rubber industrial-scale system.

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