ABSORBSI H2S MENGGUNAKAN LARUTAN Fe-EDTA DALAM PACKED COLUMN

EKUILIBIUM ◽  
2011 ◽  
Vol 10 (2) ◽  
Author(s):  
Endang Kwartiningsih ◽  
Arif Jumari
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Phase ◽  
Reaction Rate ◽  
Packed Column ◽  
Reaction Rate Constant ◽  
Absorption Process ◽  
Edta Solution

<p><strong><em>Abstract:</em></strong><strong><em> </em></strong><em>Gas purification from the content of H<sub>2</sub>S using  Fe-EDTA (Iron Chelated Solution) gave  several advantages. The advantages were  the absorbent solution can be regenerated that means  a cheap operation cost,  the separated sulfur was a solid that is easy to handle and is save to be disposal to environment. This research was done by simulation and experimental. The simulation step was done by mathematical model arrangement representing the absorption process in packed column through mass transfer arrangement such as mass transfer equations and chemical reaction. The experimental step was done with the making of Fe-EDTA solution from FeCl<sub>2</sub> and EDTA. Then Fe-EDTA solution was flown in counter current packed column that was contacted with H<sub>2</sub>S in the methane gas. By comparing gas composition result of experiment and simulation, the value of mass transfer coefficient in gas phase ( k<sub>Ag</sub>a), mass transfer coefficient in liquid phase (k<sub>Al</sub>a) and the reaction rate constant ( k) were found. The values of mass transfer coefficient in liquid phase (k<sub>Al</sub>a) were lower than values of mass transfer coefficient in gas phase (k<sub>Ag</sub>a) and the reaction rate constant (k). It meant that H<sub>2</sub>S absorption  process using Fe-EDTA absorbent solution was determined by mass transfer process in liquid phase. The higher flow rate of absorbent, the higher value of mass transfer coefficient in liquid phase. </em><em>The smaller packing diameter, the higher value of mass transfer coefficient in liquid phase.From analysis of dimension, the relation of dimensionless number between Sherwood number and flow rate of absorbent, packing diameter was</em><strong></strong></p><p> <strong><em>Keywords:</em></strong><strong><em> </em></strong><em>chemical reaction, Fe-EDTA, H<sub>2</sub>S absorption, mass transfer</em></p>

Comparison of Overall Gas-Phase Mass Transfer Coefficient for CO2Absorption between Tertiary Amines in a Randomly Packed Column

2015 ◽  
Vol 38 (8) ◽  
pp. 1435-1443 ◽  
Author(s):  
Le Wen ◽  
Helei Liu ◽  
Wichitpan Rongwong ◽  
Zhiwu Liang ◽  
Kaiyun Fu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Phase ◽  
Packed Column ◽  
Tertiary Amines

Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column

2019 ◽  
Vol 41 (5) ◽  
pp. 820-820
Author(s):  
Pongayi Ponnusamy Selvi and Rajoo Baskar Pongayi Ponnusamy Selvi and Rajoo Baskar
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Flow ◽  
Aqueous Ammonia ◽  
Volume Flow Rate ◽  
Packed Column ◽  
Operating Conditions ◽  
Co2 Absorption ◽  
Absorption Column

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.

A Simplified Thermodynamic Analysis of a LiBr-H2O Vertical Tube Absorber

2002 ◽  
Author(s):  
E. D. Rogdakis ◽  
V. D. Papaefthimiou
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Water Vapour ◽  
Liquid Water ◽  
Mass Fraction ◽  
Superheated Steam ◽  
Vertical Tube ◽  
Solution Temperature ◽  
Absorption Process

One of the most important components of an absorption air-conditioning/heat pump system is the absorber, where the refrigerant water vapour is absorbed into the liquid solution. While absorption systems have been in use for several years, the complex transport phenomena occurring in the absorber are not fully elucidated yet. Thus, an attempt is made to model the absorption process of water vapour in aqueous solutions of lithium bromide considering a falling-film, vertical-tube absorber. The proposed analysis is based on the formulation of four differential equations describing the spatial variation (parallel to the tube-axis) of solution mass, temperature, mass fraction and coolant temperature. The system of ordinary differential equations is numerically solved using a non-stiff numerical method. Thermophysical properties and especially, heat and mass transfer coefficients are calculated using widely-accepted and reliable relationships, which are extracted from the literature using recently published information on wavy-laminar flows. In the present study, the questionable assumption of treating the water vapour as an ideal gas is heavily modified utilizing. Consequently, the hypothesis of saturated water vapour at the steam-solution interaction surface is revised by introducing an energy difference between the superheated steam and the liquid water within the binary solution. The last correction encouraged us to compare theoretical results for solution temperature, mass fraction and mass flow rate, which were obtained using both assumptions. It was proved that the initial treatment causes an underestimation of the absorbed steam mass and correspondingly, an underestimation of solution temperature and mass fraction at the mass exchange interface. An attempt is made also to identify the effect of mass transfer coefficient on the effectiveness of the absorption process and on the energy differences between the superheated steam and the liquid water either as pure substance or as component of the binary mixture. It was shown that the increase of mass transfer coefficient leads to an increase of steam mass transfer rate and to a corresponding decrease of solution temperature slope at the entrance of a tube. Correspondingly, the increase of mass transfer coefficient results in an increase of heat of absorption and heat of dilution at the same variation range of the solution mass fraction.

scholarly journals Aeration / Stripping of n-Butyl Mercaptan in aqueous environment

2013 ◽  
Vol 8 (2) ◽  
pp. 103-112
Keyword(s):  
Experimental Data ◽  
Water Quality ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Chemical Equilibrium ◽  
Reaction Rate ◽  
Reaction Parameter ◽  
Ph Values ◽  
Neutral Compound

Μany applications in water quality management have a common key water quality parameter, dissolved oxygen, resulting to the critical role of aeration. On the other hand, in municipal and industrial wastewater, especially where aeration is applied, the presence of volatile organic compounds (VOCs) causes several concerns including a direct threat to humans, partly due to their emission from treatment tanks. pH, temperature and Henry’s Law govern VOCs’ speciation and consequently their emission characteristics. Limited data and simplifications of available mass-transfer models pose obstacles to a realistic approach, especially in the presence of a chemical equilibrium, for example in the case of mercaptans. In the present study the importance of oxygen transfer and stripping of a VOC (n-butyl mercaptan) on aeration’s overall effectiveness are examined separately. Clean water oxygenation and stripping of mercaptan to an inert gas (nitrogen) were studied aiming to consider mass transfer aspects and to investigate the influence of chemical equilibrium between ionic and neutral form of the target compound in neutral and alkaline solutions. Using appropriate mass transfer relationships (dynamic method), experimental data were analyzed for the determination of overall mass transfer coefficient ( kOL,O2α ) of oxygen. Correlating kOL,O2 α with the corresponding mass transfer coefficient of n-butyl mercaptan in neutral solutions (calculated according the model proposed by Matter-Muller et al. [1]), a value of ratio βy of 0.566 is found, close to the reported values of other VOCs with similar values of Henry’s constant. At alkaline pH however the conventional simplified model fails to predict realistic values of mass-transfer coefficients. A coupled differential algebraic equation system, based on mass balances, taking into account dissociation of the compound to be stripped and assuming chemical non-equilibrium conditions during stripping, was developed. Reaction parameter k2 was calculated with non-linear least-squares analysis. The model predicts satisfactorily the experimental data and it provides a useful tool for the semibatch stripper design in situations where a reversible reaction is involved. At pH values below 8.5 mercaptan concentration falls exponentially whereas above 10.5 it tends to linearity. The bubble equilibrates and mercaptan transferred depends upon solubility and not diffusivity. Especially after depletion of initial neutral compound, transport depends upon neutral/ionic form speciation. The effectiveness of stripping n-butyl mercaptan, at a given pH, is mainly determined by a proportionality constant considered as “fugacity capacity” (removal effect on the process) and by a reversible reaction rate constant k2 (kinetic effect on the process). The ‘’fugacity capacity” is determined by hydrophobicity (i.e. low solubility and high limiting activity coefficient) rather than pure-component volatility (i.e. vapor pressure or boiling point). High limiting activity coefficient promotes mercaptan emission due to established vapor-liquid equilibrium, while the low reaction parameter k2, controls neutral compound quantity. At high pH, where ionic form predominates, experimental data showed that stripping was almost independent of the gas flow rate applied. A strong sensitivity of the model to uncertainty of γ∞ was found: γ∞ controls emission rate and through this the dynamic variations of neutral/ionic concentration profiles whereas reaction rate law parameter k2 controls the neutral/ionic transformation and it is the crucial quantity which governs the process at high pH values.

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