Effect of Gas Flow Rate on Degradation of 2,4-D with O3 and O3/H2O2

2012 ◽  
Vol 433-440 ◽  
pp. 221-226
Author(s):  
Lan Chen ◽  
Yu Heng Quan
Keyword(s):  
Hydrogen Peroxide ◽  
Mass Transfer ◽  
Production Rate ◽  
Flow Rate ◽  
Gas Flow ◽  
Batch Reactor ◽  
Gas Flow Rate ◽  
Transfer Condition ◽  
Flow Rates ◽  
2,4 Dichlorophenoxyacetic Acid

The effect of gas flow rate on degradation of chlorinated phenoxy acetic acids herbicide 2,4-D(2,4-dichlorophenoxyacetic acid) in aqueous solution with O3 or O 3/H 2O2 process was investigated in a bubbling semi-batch reactor. The experiments were conducted to study the degradation rate constant, mass transfer condition, ozone consumption and formation of byproduct hydrogen peroxide at different gas flow rates. The results show that gas flow rate is a complicated parameter in the process. The contact time of gas and liquid phase varies with different gas flow rate, consequently ozone mass transfer condition changes with different gas flow rates. The production rate of ozone, amount of ozone in the end gas and ozone consumption during the degradation with ozonation and O 3/H2O2 process vary with different of gas flow rates. Hydrogen peroxide is a byproduct during the ozonation or O3/H2O2 process of 2,4-D. The production rate of hydrogen peroxide is also affected by the gas flow rate. In general gas flow rate has both positive and negative effect on the 2,4-D degradation.

scholarly journals TOTAL VOLUMETRIC MASS TRANSFER COEFFICIENT AT CO2 GAS ABSORPTION USING K2CO3 BY MSG PROMOTER

Konversi ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Erlinda Ningsih ◽  
Abas Sato ◽  
Mochammad Alfan Nafiuddin ◽  
Wisnu Setyo Putranto
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Liquid Flow ◽  
Total Mass ◽  
Gas Flow ◽  
Liquid Flow Rate ◽  
Gas Flow Rate ◽  
Co2 Gas

Abstract- One of the most widely used processes for CO2 gas removal is Absorption. Carbon dioxide is the result of the fuel combustion process which of the hazardous gases. The aim of this research is to determine the total mass transfer coefficient and analyze the effect of the absorbent flow rate of the absorbent solution with the promoter and the gas flow rate to the total mass transfer coefficient value. The variables consisted of liquid flow rate: 1, 2, 3, 4, 5 liter/min, gas flow rate: 15, 25, 30, 40, 50 liter/min and MSG concentration: 0%, 1%, 3% and 5% by weight. The solution of Pottasium Carbonate as absorbent with MSG promoter is flowed through top column and CO2 gas flowed from bottom packed column. Liquids were analyzed by titration and the gas output was analyzed by GC. From this research, it is found that the flow rate of gas and the liquid flow rate is directly proportional to the value of KGa. The liquid flow rate variable 5 liters / minute, gas flow rate 15 l / min obtained value of KGa 11,1102 at concentration of MSG 5%. Keywords:  Absorption, CO2,  K2CO3, MSG. 

scholarly journals NO Separation Characteristics in Integrated Electromigration Membrane Reactor

2020 ◽  
Vol 10 (15) ◽  
pp. 5071
Author(s):  
Zuwu Wang ◽  
Guifen Shen
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Total Mass ◽  
Membrane Reactor ◽  
Gas Flow ◽  
Separation Efficiency ◽  
Discharge Voltage ◽  
Gas Flow Rate

An integrated electromigration membrane absorption method has been proposed for the separation of NO from simulated mixed gas. The experiments were conducted to investigate the effect of discharge voltage, gas flow rate, inlet concentrations, and absorbents on the NO separation efficiency and total mass transfer coefficient in the integrated electromigration membrane reactor. The experimental results demonstrated that the NO separation efficiency and total mass transfer coefficient increased with the increase in the applied discharge voltage of the integrated electromigration membrane reactor. Regardless of discharge or not, the separation efficiency of NO continuously decreased with the increase in the gas flow rate and inlet concentration of NO in the experimental process. The total mass transfer coefficient of NO increased first and then decreased with an increase in the gas flow rate, while it decreased with an increase in NO inlet concentration. Compared with the membrane absorption without discharge voltage under the condition tested, at a discharge voltage of 18kV, the NO separation efficiency and the total mass transfer coefficient increased by 48.7% and 9.7 times, respectively.

scholarly journals Influence of Pressure on Gas/Liquid Interfacial Area in a Tray Column

2020 ◽  
Vol 10 (13) ◽  
pp. 4617
Author(s):  
Adel Almoslh ◽  
Falah Alobaid ◽  
Christian Heinze ◽  
Bernd Epple
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Volumetric Flow Rate ◽  
Interfacial Area ◽  
Gas Flow Rate ◽  
Test Rig ◽  
Flow Rates ◽  
Waste Gas ◽  
Simulated Waste ◽  
Series Of Experiments

The influence of pressure on the gas/liquid interfacial area is investigated in the pressure range of 0.2–0.3 MPa by using a tray column test rig. A simulated waste gas, which consisted of 30% CO2 and 70% air, was used in this study. Distilled water was employed as an absorbent. The temperature of the inlet water was 19 °C. The inlet volumetric flow rate of water was 0.17 m3/h. Two series of experiments were performed; the first series was performed at inlet gas flow rate 15 Nm3/h, whereas the second series was at 20 Nm3/h of inlet gas flow rate. The results showed that the gas/liquid interfacial area decreases when the total pressure is increased. The effect of pressure on the gas/liquid interfacial area at high inlet volumetric gas flow rates is more significant than at low inlet volumetric gas flow rates. The authors studied the effect of decreasing the interfacial area on the performance of a tray column for CO2 capture.

Direct molecular hydrogen sulphide scrubbing with hollow fibre membranes

2001 ◽  
Vol 44 (9) ◽  
pp. 135-142 ◽  
Author(s):  
N. Boucil ◽  
B. Jefferson ◽  
S.A. Parsons ◽  
S.J. Judd ◽  
R.M. Stuetz
Keyword(s):  
Mass Transfer ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Flow Rate ◽  
Hydrogen Sulphide ◽  
Gas Flow ◽  
Hollow Fibre ◽  
The Other ◽  
Gas Flow Rate

The emission of hydrogen sulphide is a major problem associated with anaerobic treatment of sulphate and sulphite containing wastewaters. Conventional absorbing processes, such as packed towers, spray towers or bubble columns, are all constrained by factors such as flooding and foaming. Membrane systems, on the other hand, enable independent control of the liquid and gas flow rate and a step change order of magnitude increase in the specific surface area of the contact process. The membrane acts as a gas absorber with a design similar to a shell and tube heat exchanger. On the other hand, they are limited by facets of the membrane such as its resistance to mass transfer and permselectivity, as well as its cost. The work presented in this paper refers to an absorption process based on a non-wetted hollow fibre membrane for the scrubbing of hydrogen sulphide from air, with water as the contact solvent. Results presented describe the performance of the unit in terms of overall transfer and outlet liquid concentration as a function of circulation regime, gas flow rate, liquid flow rate and specific surface area. In particular, results are presented using traditional plots of Sherwood number (Sh) against Graetz (Gr) number for the liquid flowing in the lumens, such that experimental and available empirical descriptions of the process performance are directly compared. Results suggest that, as expected, very efficient mass transfer is obtained. However, the mass transfer was found to reach a maximum value against Gr, contrary to available empirical models.

Effect of Inner Cavity’s Gas Flow Rate on the Extrusion Forming of Plastic Micro-Pipe

2020 ◽  
Vol 842 ◽  
pp. 279-284
Author(s):  
Zhong Ren ◽  
Xing Yuan Huang
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Flow Rate ◽  
Gas Flow ◽  
Normal Stress Difference ◽  
Stress Difference ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
First Normal Stress Difference ◽  
Extrusion Forming

During the manufacture of plastic micro-pipe, a certain volume of gas should be properly injected into the inner cavity to overcome the collapse and adhesion problems. In this work, the extrusion forming of plastic micro-tube under the role of inner cavity’s gas were numerically studied. At the same time, the effect of inner cavity’s gas flow rate on the extrusion deformation of plastic micro-pipe was also numerically investigated by using the finite element method. A kind of 2D two-phase fluid geometric model and finite element mesh were established and some reasonable boundary conditions and material parameters were imposed. Under a fixed volume flow rate of melt, different flow rates of inner cavity gas were imposed on the inlet of inner cavity’s gas. The extrusion deformation profile and deformation ratio of plastic micro-pipe under different flow rates of gas were all obtained. To ascertain the mechanisms of effect of inner cavity’s gas flow rate on the extrusion deformation of plastic micro-tube, the flow velocities, pressure, shear rate, normal stress, and the first normal stress difference of melt all obtained and analyzed. Numerical results show that with the increase of inner cavity’s gas flow rate, the radial velocity, axial velocity, pressure, shear rate, normal stress, and the first normal stress difference of melt all increase, which makes the extrusion deformation become more and more serious. In practice, reasonable controlling of the inner cavity’s gas flow rate is very important. In the other hand, it can adjust the size of extruded plastic micro-pipe.

Effects of Gas Flow Rate and Catalyst Loading on Polymer Electrolyte Membrane (PEM) Fuel Cell Performance and Degradation

2010 ◽  
Author(s):  
A. Chukwujekwu Okafor ◽  
Hector-Martins Mogbo
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Polymer Electrolyte Membrane ◽  
Open Circuit ◽  
Catalyst Loading ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Electrolyte Membrane

In this paper, the effects of gas flow rates, and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50cm2 active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane Electrode Assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5mg/cm2, 1mg/cm2; 0.3L/min, 0.5L/min respectively) were tested at 60°C without humidification. The cell performance was analyzed by taking AC Impedance, TAFEL plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. TAFEL plot shows the highest exchange current density value of −2.05 mAcm2 for MEA with 0.5mg/cm2 catalyst loading operated at reactant gas flow rate of 0.3L/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.

High-Accuracy Wet-Gas Multiphase Well Testing and Production Metering

SPE Journal ◽  
2006 ◽  
Vol 11 (02) ◽  
pp. 199-205 ◽  
Author(s):  
David I. Atkinson ◽  
Oyvind Reksten ◽  
Gerald Smith ◽  
Helge Moe
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Gas Flow ◽  
Volume Fraction ◽  
Well Testing ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Wet Gas ◽  
New Interpretation ◽  
Interpretation Model

Summary Dedicated wet-gas flowmeters are now commercially available for the measurement of gas and liquid flow rates and offer a more compact measurement solution than does the traditional separator approach. The interpretation models of traditional multiphase flowmeters emphasize the liquid rate measurements and have been used to well test and meter mostly liquid-rich flow streams. These models were not developed for the measurement of gas flow rates, particularly those of wet gas. A new interpretation is described that allows a traditional multiphase flowmeter to operate in a dual mode either as a multiphase meter or as a wet-gas meter in 90 to 100% gas. The new interpretation model was developed for a commercially available multiphase flowmeter consisting of a venturi and a dual-energy composition meter. This combination results in excellent predictions of the gas flow rate; the liquid rate prediction is made with acceptable accuracy and no additional measurements. The wet gas and low-liquid-volume-fraction interpretation model is described together with the multiphase flowmeter. Examples of applying this model to data collected on flow loops are presented, with comparison to reference flow rates. The data from the Sintef and NEL flow loops show an error (including the reference meter error) in the gas flow rate, better than ± 2% reading (95% confidence interval), at line conditions; the absolute error (including the reference meter error) in the measured total liquid flow rate at line conditions was better than ± 2 m3/h (< ± 300 B/D: 95% confidence interval). This new interpretation model offers a significant advance in the metering of wet-gas multiphase flows and yields the possibility of high accuracies to meet the needs of gas-well testing and production allocation applications without the use of separators. Introduction There has been considerable focus in recent years on the development of new flow-measurement techniques for application to surface well testing and flow-measurement allocation in multiphase conditions without separating the phases. This has resulted in new technology from the industry for both gas and oil production. Today, there are wet-gas flowmeters, dedicated to the metering of wet-gas flows, and multiphase meters, for the metering of multiphase liquid flows. The common approach to wet-gas measurement relates gas and liquid flows to a "pseudo-gas flow rate" calculated from the standard single-phase equations. This addresses the need for gas measurement in the presence of liquids and can be applied to a limit of liquid flow [or gas volume fraction, (GVF)], though the accuracy of this approach decreases with decreasing GVF. The accurate determination of liquid rates by wet-gas meters is restricted in range. The application and performance of multiphase meters has been well documented through technical papers and industry forums, and after several years of development is maturing (Scheers 2004). Some multiphase measurement techniques can perform better, and the meters provide a more compact solution, than the traditional separation approach. It is not surprising that the use of multiphase flowmeters has grown significantly, the worldwide number doubling in little over a 2-year period (Mehdizadeh et al. 2002). Multiphase-flowmeter interpretation emphasizes the liquid rate measurement, and the application of multiphase flowmeters has been predominantly for liquid-rich flow stream allocation and well testing.

Effect of Powder Flow Rate and Gas Flow Rate on the Evolving Properties of Deposited Ti6Al4V/Cu Composites

2014 ◽  
Vol 1016 ◽  
pp. 177-182 ◽  
Author(s):  
Mutiu F. Erinosho ◽  
Esther Titilayo Akinlabi ◽  
Sisa Pityana
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Pure Copper ◽  
Metal Deposition ◽  
Powder Flow ◽  
Laser Metal Deposition ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Powder Flow Rate ◽  
Hardness Values

—Pure copper was deposited with Ti6Al4V alloy via laser metal deposition (LMD) process to produce Ti6Al4V/Cu composites. This paper reports the effect of powder flow rate (PFR) and gas flow rate (GFR) of laser metal deposited Ti6Al4V/Cu composites. The deposited samples were characterised through the evolving microstructure and microhardness. It was observed that the PFR and GFR have an influence on the percentage of porosity present in the samples. The higher the flow rates of the powder and the gas, the higher the degree of porosity and vice versa. The widmanstettan structures were observed to be finer as the flow rate reduces which in turn causes a decrease in the hardness values of the deposited composites. The hardness values varied between HV381.3 ± 60 and HV447.3 ± 49.

Investigation of the Effects of Catalyst Loading and Gas Flow Rate on Polymer Electrolyte Membrane (PEM) Fuel Cell Performance and Degradation

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Anthony C. Okafor ◽  
Hector-Martins C. Mogbo
Keyword(s):  
Fuel Cell ◽  
Flow Rate ◽  
Gas Flow ◽  
Open Circuit Voltage ◽  
Polymer Electrolyte Membrane ◽  
Open Circuit ◽  
Catalyst Loading ◽  
Gas Flow Rate ◽  
Flow Rates ◽  
Electrolyte Membrane

In this paper, the effects of gas flow rates and catalyst loading on polymer electrolyte membrane fuel cell (PEMFC) performance was investigated using a 50 cm2active area fuel cell fixture with serpentine flow field channels machined into poco graphite blocks. Membrane electrode assemblies (MEAs) with catalyst and gas flow rates at two levels each (0.5 mg/cm2, 1 mg/cm2; 0.3 l/min, 0.5 l/min, respectively) were tested at 60 °C without humidification. The cell performance was analyzed by taking ac impedance, Tafel plot, open circuit voltage, and area specific resistance measurements. It was observed that MEAs with lower gas flow rate had lesser cell resistance compared to MEAs with a higher gas flow rate. Tafel plot shows the highest exchange current density value of 10−2.05 mA cm2 for MEA with 0.5 mg/cm2 catalyst loading tested at reactant gas flow rate of 0.3 l/min signifying it had the least activation loss and fastest reaction rate. Open circuit voltage-time curve shows a higher output voltage and lesser voltage decay rate for MEAs tested at higher gas flow rates.

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