Axial Dispersion in an Apparatus with Mobile Packing

1993 ◽  
Vol 58 (5) ◽  
pp. 1069-1077
Author(s):  
Zdeněk Palatý

The paper deals with modelling of the flow of liquid on a plate with mobile packing. The results of measurements have been interpreted by means of a simple dispersion model whose two parameters were determined from the nonideal step-input of a tracer and its response. It has been found that in the gas flow rate region followed (1.0 - 3.5 m s-1), the liquid flow rate followed (5.36 - 12.5 . 10-3 m s-1), and the static bed height followed (21 - 47 . 10-3 m) the diffusion Peclet number is independent of these quantities. The mean residence time of the liquid on the plate decreases with increasing flow rate of Both gas and liquid, but it increases with the increasing height of packing.

Konversi ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Erlinda Ningsih ◽  
Abas Sato ◽  
Mochammad Alfan Nafiuddin ◽  
Wisnu Setyo Putranto

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. 


1994 ◽  
Vol 29 (10-11) ◽  
pp. 231-241 ◽  
Author(s):  
H. T. Chang ◽  
B. E. Rittmann

This paper presents a unified model that inter-relates gas flow rate, liquid flow rate, and hold-ups of each of the liquid, gas, and solid phases in three-phase, fluidized-bed biofilm (TPFBB) process. It describes how carrier properties, biofilm properties, and gas and liquid flow velocities control the system dynamics, which ultimately will affect the density, thickness, and distribution of the biofilm. The paper describes the development of the mathematical model to correlate the effects of gas flow rate, liquid flow rate, solid concentration, and biofilm thickness and density. This knowledge is critically needed in light of the use of TPFBB processes in treating industrial wastewater, which often has high substrate concentration. For example, the proper design of the TPFBB process requires mathematical description of the cause-effect relationship between biofilm growth and fluidization.


2012 ◽  
Vol 573-574 ◽  
pp. 538-541
Author(s):  
Yan Ping Duan ◽  
Sven Geissen ◽  
Ling Chen

Ozonation of clofibric acid (CA) in aqueous solution was carried out under continuous operation in a cascade bubble column. The influence of operation parameters including initial CA concentration, gas flow rate, liquid flow rate and pH on the removal of CA and TOC was investigated. The results indicated that ozonation could be used to effectively remove CA from water. Increasing the initial CA concentration resulted in a decrease of the CA and TOC removal efficiency. A comparison of CA removal efficiency and ozone utilization between cascade and conventional bubble column indicated that cascade bubble column was an effective way for increasing the solubility ozone in the reactor.


1995 ◽  
Vol 49 (3) ◽  
pp. 324-334 ◽  
Author(s):  
George R. Agnes ◽  
Gary Horlick

A parametric investigation of an electrospray ion source and interface has been carried out with a focus on elemental analysis. The source and interface variables investigated were the curtain-gas flow rate and the voltage biases of the electrospray capillary tip, the front plate, the sampling plate, the skimmer, and the barrel ion extractor lens. The analytes studied (M+ and M++) included the alkali metals, the alkaline earth metals, and cobalt—all prepared in methanol (MeOH) solutions. The two most important interface parameters in terms of their effect on the nature of the resulting mass spectrum were the curtain-gas flow rate and the sampling-plate voltage bias. A minimum, but modest, flow rate of curtain gas was required in order to observe analyte ion signals, and, when combined with a low sampling-plate voltage, the observed signal species were primarily analyte ion–solvent clusters [M(MeOH) n+1 and M(MeOH) m+2]. As the values of these two parameters were increased, these species were declustered, plus-two analyte ions were reduced to plus-one species, and ultimately the mass spectra were dominated by the bare singly charged analyte ion (M+). Also, these two variables (curtain-gas flow rate and sampling-plate voltage) seem to act in a synergistic manner, with neither variable alone able to effect complete declustering and charge reduction.


1985 ◽  
Vol 39 (6) ◽  
pp. 920-925 ◽  
Author(s):  
R. K. Skogerboe ◽  
S. J. Freeland

The effects of nebulization conditions on the size characteristics of the aqueous aerosol produced have been investigated for a cross-flow nebulizer. It is shown that the nebulizer gas flow rate does not affect the upper limit mean sizes of the aqueous droplets transported from the nebulization chamber but that the mean size of the analyte-containing aerosol itself is affected. Model equations are presented descriptive of the effects of gas flow rate and analyte concentrations on analyte aerosol size characteristics.


1989 ◽  
Vol 8 (2) ◽  
pp. 63-68
Author(s):  
A. J. Rautenbach ◽  
G. Kornelius

Spray columns are widely used in industry as a gas-liquid contacting apparatus because of the advantages of a high transfer area per unit volume and the tow gas side resistance. For a large number of systems, mass transfer parameters are not available and an experimental determination for the system benzene/wash oil was therefore carried out. The experimental technique and design are described. The variation in mass transfer coefficient as function of gas flow rate, liquid flow rate and column height agrees with those published elsewhere.


Nowadays, CO2 as the product of fossil fuel combustions, is polluting the air and the human environment, and it causes global warming. To reduce the negative effect of CO2 presence, it should be removed from the air by capturing methods. Hollow fiber membrane contactor (HFMC) system is one of the most efficient method for CO2 capturing than the other feasible capturing methods. In the present paper an HFMC absorbing system has been simulated using COMSOL Multiphysics software and the effect of flow rates of gas and liquid on the amount of CO2 removal has been studied. Aqueous solution of Mono-ethanolamine (MEA) is entered as the absorbent liquid in the tubes, and CO2 is removed from the shell side by the diffusion phenomena by participating in the chemical reaction with MEA. The results show that the higher liquid flow rate the higher %CO2 removal from the inserted gas. Against this result, the percentage of CO2 removal decreases with increasing the gas flow rate as expected. Higher gas flow rate leads the gas velocity to higher values and less possibility of absorbing by the diffusion method. The rate of the CO2 removal variation with liquid flow rate is higher than the CO2 removal variation whit the gas flow rate.


2019 ◽  
Vol 3 (2) ◽  
pp. 57
Author(s):  
Éric Dumont

In this study, the Effectiveness-NTU method, which is usually applied to heat exchanger design, was adapted to gas–liquid countercurrent absorbers to determine the overall mass transfer coefficient, KLa, of the apparatus in operation. It was demonstrated that the ε-NTU method could be used to determine the KLa using the Henry coefficient of the solute to be transferred (HVOC), the gas flow-rate (QG), the liquid flow-rate (QL), the scrubber volume (V), and the effectiveness of the absorber (ε). These measures are calculated from the gaseous concentrations of the solute measured at the absorber inlet (CGin) and outlet (CGout), respectively. The ε-NTU method was validated from literature dedicated to the absorption of volatile organic compounds (VOCs) by heavy solvents. Therefore, this method could be a simple, robust, and reliable tool for the KLa determination of gas–liquid contactors in operation, despite the type of liquid used, i.e., water or viscous solvents.


2016 ◽  
Vol 859 ◽  
pp. 153-157
Author(s):  
Pao Chi Chen ◽  
Sheng Zhong Lin

This work uses a continuous bubble-column scrubber for the absorption of CO2 with a 5M MEA solution under a constant pH environment to explore the effect of the pH of the solution and gas-flow rate (Qg) on the removal efficiency (E), absorption rate (RA), overall mass-transfer coefficient (KGa), liquid flow rate (QL), gas-liquid flow ratio (γ), and scrubbing factors (φ). From the outlet CO2 concentration with a two-film model, E, RA, KGa, QL, γ, and φ can be simultaneously determined at the steady state. Depending on the operating conditions, the results show that E (80-97%), RA(2.91x10-4-10.0x10-4mol/s-L), KGa (0.09-0.48 1/s), QL(8.74-230.8mL/min), γ (0.19-5.39), and φ (0.031-0.74 mol/mol-L) are found to be comparable with other solvents. In addition, RA, KGa, E, and QL have been used to correlate with pH and Qg, respectively, with the results further explained.


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