Experimental Research for SO2 Absorption in Bubbling Stirring Reactor

2010 ◽  
Vol 113-116 ◽  
pp. 339-342
Author(s):  
Su Min Lu ◽  
You Guang Ma ◽  
Shu Hua Shen ◽  
Chun Ying Zhu
Keyword(s):  
Mass Transfer ◽  
Citric Acid ◽  
Removal Efficiency ◽  
Residence Time ◽  
Experimental Research ◽  
Gas Flow ◽  
Buffer Action ◽  
So2 Removal ◽  
Liquid Mass Transfer ◽  
So2 Absorption

The effect of different parameters on SO2 absorption was investigated in a semi-batchwise bubbling stirring reactor. From the experimental results, an increase of the gas flow, which substantially decreased the residence time of the gas in liquid, led to a quick reduce of the time of 100% removal efficiency of SO2. The addition of CaCO3 increased the removal efficiency of SO2 significantly. With increasing the concentration of CaCO3, the time of SO2=100% was almost increased linearly. The increase of the stirring speed prolonged the time of SO2=100% at first, but when beyond a certain value, no further effect of the stirring speed was observed, which showed that the mass transfer of SO2 in slurry was controlled by both gas and liquid mass transfer. Citric acid displays a good buffer action on SO2 absorption. The addition of citrate prolonged the time in which the SO2 removal efficiency remained high valves.

scholarly journals The Effect of Mass Transfer Rate-Time in Bubbles on Removal of Azoxystrobin in Water by Micro-Sized Jet Array Discharge

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1169
Author(s):  
Feng Chen ◽  
Dezheng Yang ◽  
Feng Yu ◽  
Yang Kun ◽  
Ying Song
Keyword(s):  
Mass Transfer ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Applied Voltage ◽  
Transfer Rate ◽  
Gas Flow ◽  
Mass Transfer Rate ◽  
Initial Solution ◽  
Solution Temperature ◽  
Gas Flow Rate

In this work, the azoxystrobin removal in water by using a micro-size discharge array was investigated, and the removal efficiency can reach as high as 98.1% after 9 min plasma treatment as well as the energy utilization being only 0.73 g/(kW·h). Based on the relationship between the generation of gas bubbles and parameters of gas-liquid discharge, it was found that the variation of applied voltage, gas flow rate and initial solution temperature could cause particle number change, mass transfer rate change and the mass transfer time change, which significantly affected the practical applications at last. The experimental results indicated that when gas flow rate was 0.7 SLM (Standard Liter per Minute) and the initial solution temperature was 297 K with the applied voltage of 8 kV and discharge frequency of 6 kHz, the removal efficiency of azoxystrobin achieved maximum. Based on the analysis results of liquid mass spectrometry, the removal pathways of azoxystrobin were supposed by the decomposed by-products. Toxicity tests indicated that the decomposed products were safe and non-toxic. So, this study may reveal an azoxystrobin degradation mechanism and provide a safe, reliable and effective way for azoxystrobin degradation.

Carbochlorination of Fly Ash in a Fused Salt Slurry Reactor

1986 ◽  
Vol 86 ◽  
Author(s):  
M. S. Dobbins ◽  
G. Burnet
Keyword(s):  
Mass Transfer ◽  
Fly Ash ◽  
Gas Flow ◽  
Mixed Oxides ◽  
Batch Reactor ◽  
Coal Fly Ash ◽  
Pure Alumina ◽  
Higher Temperature ◽  
Liquid Mass Transfer ◽  
Temperature Oxide

ABSTRACTCarbochlorination of the metal oxides in fly ash by suspending the solid reactants in a NaCl-AlCl3 melt at 530–850°C and then sparging chlorine into the melt has been investigated. A mechanically agitated, semi-batch reactor was used to test the effects of temperature, oxide and carbon loading, salt composition and gas flow on the reaction rate. The process was modeled using the carbochlorination of pure alumina, the rate of which was found to be chemical reaction controlled at temperatures below about 650°C and gas-liquid mass transfer controlled at higher temperature. The carbochlorination rate of the mixed oxides in coal fly ash was also mass transfer controlled at higher temperatures when aluminum recoveries were less than about 50%. At higher aluminum recoveries, the overall rate was limited by the rate of ash dissolution into the melt.

Uncatalyzed Oxidation of Cyclohexane in the Microchannels

2013 ◽  
Vol 562-565 ◽  
pp. 1542-1547
Author(s):  
Lei Wang ◽  
Ming Qiao Zhu ◽  
Jian Gang Lu ◽  
Hong Ding Hu
Keyword(s):  
Mass Transfer ◽  
Residence Time ◽  
Oxidation Reaction ◽  
Plug Flow ◽  
Industrial Applications ◽  
Molar Ratio ◽  
New Process ◽  
Good Potential ◽  
Liquid Mass Transfer ◽  
Micro Mixer

The oxidation of cyclohexane in the microchannels not only improves the safety of the reaction, but also the performance of the oxidation reaction. Different gas-liquid micro mixers were used for the mixing of gas and liquid before entering into microchannels, and SIMM-V2 performed best of all. Excellent slug/plug flow can be formed in the microchannels after mixing in the gas-liquid micro mixer when the molar ratio of oxygen to cyclohexane is less than 0.5:1. The conversion of cyclohexane increased as the residence time increased, but the selectivity of cyclohexanol and cyclohexanone increased first and then decreased. At the reaction temperature of 200 °C, with the flow rate of the solvent isopropanol being 1 mL/min and the molar ratio of oxygen to cyclohexane being 0.15:1, both the conversion of cyclohexane and selectivity of cyclohexanol and cyclohexanone increased with the increase of pressure. The conversion of cyclohexane and selectivity of cyclohexanol and cyclohexanone reached 10.10% and 66.93% respectively at the pressure of 8 MPa. It is indicated that the new process by use of uncatalyzed cyclohexane oxidation in the microchannels will have very attractive prospects in the improvement of the safety, intensification of the gas-liquid mass transfer and obtaining good reactive performance. Therefore, the technology shows good potential in industrial applications.

Toluene removal in a biofilm reactor for waste gas treatment

1997 ◽  
Vol 36 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Anne R. Pedersen ◽  
Erik Arvin
Keyword(s):  
Mass Transfer ◽  
Gas Flow ◽  
Biofilm Reactor ◽  
Biological Degradation ◽  
Gas Treatment ◽  
Waste Gas ◽  
Filter Performance ◽  
Liquid Mass ◽  
Toluene Removal ◽  
Liquid Mass Transfer

A lab-scale trickling filter for treatment of toluene-containing waste gas was investigated. The filter performance was investigated for various loads of toluene. Two levels of the gas flow were examined, 322 m d−1 and 707 m d−1. The gas inlet concentrations were varied in the range from 0.6 to 4.0 g m−3. The toluene elimination increased linearly with increasing load, and at maximum load the elimination was 50 g m−3 h−1 (70% purification efficiency). This was in accordance with reported values for toluene removal in trickling filters. The removal was determined by the gas/liquid mass transfer and the biological degradation as well. An analytical model described the toluene removal as a half-order removal by use of two sets of parameters for the gas/liquid mass transfer and the biological degradation due to the two different gas flows. The mass transfer coefficients and the surface removal rates estimated by parameter fitting corresponded to previously observed values. The effect of the gas flow on the mass transfer coefficient and the biological removal rate may be explained by different flow patterns of the gas and the liquid phases. A characterisation of the biofilm showed an almost even biofilm growth over the filter height, which was in accordance with a constant liquid concentration throughout the column.

scholarly journals CO2 absorption in flat membrane microstructured contactors of different wettability using aqueous solution of NaOH

2018 ◽  
Vol 7 (6) ◽  
pp. 471-476 ◽  
Author(s):  
Achilleas Constantinou ◽  
Simon Barrass ◽  
Asterios Gavriilidis
Keyword(s):  
Mass Transfer ◽  
Removal Efficiency ◽  
Residence Time ◽  
Single Channel ◽  
Co2 Absorption ◽  
Membrane Contactor ◽  
Transfer Resistance ◽  
Ptfe Membrane ◽  
Naoh Solution ◽  
Flat Membrane

Abstract CO2 absorption in solutions of sodium hydroxide (NaOH) was performed in three membrane/mesh microstructured contactors: a single-channel polytetrafluoroethylene (PTFE) membrane contactor, a nickel mesh contactor and an eight-channel PTFE membrane contactor. A membrane/mesh was used to achieve gas/liquid mass transfer without dispersion of one phase within the other. The PTFE membrane consisted of a pure PTFE layer 20 μm thick laminated onto a polypropylene (PP) layer of 80 μm thickness. The pure PTFE layer contained pores of ~0.5 to 5 μm diameter and was hydrophobic, while the PP layer consisted of rectangular openings of 0.8 mm×0.324 mm and was hydrophilic. The nickel mesh was 25 μm thick and contained pores of 25 μm diameter and was hydrophilic. Experiments were performed with a 2 m NaOH solution and an inlet feed of 20 vol % CO2/N2 gas mixture. Numerical simulations matched reasonably well the experimental data. CO2 removal efficiency increased by increasing the NaOH concentration, the gas residence time and the exchange area between gas and liquid. Higher removal of CO2 was achieved when the PP was in the gas side rather than in the liquid side, due to lower mass transfer resistance of the gas phase. For the same reason, CO2 removal efficiency was higher for the eight-channel PTFE contactor compared to the nickel mesh contactor. Average CO2 flux was higher for the eight-channel contactor (8×10−3 mol/min·cm2 with PP on the gas side) compared to the nickel mesh contactor (3×10−3 mol/min·cm2) for the same gas and liquid residence times. The eight-channel PTFE membrane contactor removed around 72% of CO2 in 1.2 s gas residence time, demonstrating the potential for CO2 absorption using flat membrane contactors.

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