Gas drying using [EMIM][MeSO3] supported on silica gel in fixed-bed - study on process behavior, mass transport and modeling

2021 ◽  
pp. 132129
Author(s):  
Florian R. Radakovitsch ◽  
Andreas Jess
Keyword(s):  
Mass Transport ◽  
Silica Gel ◽  
Fixed Bed ◽  
Process Behavior

Mass Transport Model for the Fixed Bed Sorption of Metal Ions on Bone Char

2003 ◽  
Vol 42 (14) ◽  
pp. 3458-3469 ◽  
Author(s):  
Danny C. K. Ko ◽  
John F. Porter ◽  
Gordon McKay
Keyword(s):  
Mass Transport ◽  
Metal Ions ◽  
Transport Model ◽  
Fixed Bed ◽  
Bone Char ◽  
Mass Transport Model

Dehumidification and Simultaneous Removal of Selected Pollutants from Indoor Air by a Desiccant Wheel Using a 1M Type Desiccant

1999 ◽  
Vol 121 (1) ◽  
pp. 1-13 ◽  
Author(s):  
M. Popescu ◽  
T. K. Ghosh
Keyword(s):  
Silica Gel ◽  
Flow Rate ◽  
Molecular Sieve ◽  
Fixed Bed ◽  
Aluminum Foil ◽  
Time Interval ◽  
Simultaneous Removal ◽  
Desiccant Wheel ◽  
Face Velocity ◽  
Adsorption Cycle

Solid-desiccant dehumidifiers are increasingly becoming an integral part of desiccant based air-conditioning systems because of their effective handling of latent heat loads compared to conventional vapor compression units. In these units, either a silica gel or a molecular sieve is used for dehumidification of air. Both of them have the capability to co-adsorb various chemical pollutants during dehumidification of air. However, the shape of the isotherm for water vapor on these materials is not favorable for desiccant cooling applications. A mixture (IM desiccant) containing a silica gel, a molecular sieve, and a hydrophobic molecular sieve that was coated on an aluminum foil was studied for its capability for simultaneous removal of moisture and some selected pollutants from air. Experimental data were obtained in a fixed bed adsorber that simulated the operation of a rotary desiccant wheel. Air to be dehumidified and cleaned and the hot regeneration air were cycled in a specific time interval through this bed. The shape of the water isotherm on IM desiccant was found to be in between that of silica gel and molecular sieve 13×, but its uptake capacity was significantly lower than that of either silica gel or molecular sieve. A flow rate of about 100 L/min that provided a face velocity of about 132 cm/s was used in the adsorption step. The flow rate during regeneration was about 50 L/min. The temperature of the inlet air was about 23°C and its relative humidity was varied between 20 percent and 80 percent. The concentrations of pollutants were as follows; carbon dioxide: 1050 and 2300 ppm; toluene: 32 ppm; 1,1,1-trichloroethane: 172 ppm, and formaldehyde: 0.35 ppm. A complete breakthrough of all the pollutants was observed during an adsorption cycle. However, a removal efficiency greater than 50 percent for these pollutants was observed if the adsorption cycle time was about 1 minute.

PENGERINGAN ETANOL DALAM KOLOM UNGGUN TETAP DENGAN ADSORBENT SILICA GEL

EKUILIBIUM ◽  
2011 ◽  
Vol 10 (2) ◽  
Author(s):  
Endah Retno Dyartanti
Keyword(s):  
Silica Gel ◽  
Fixed Bed ◽  
Ethanol Vapor ◽  
Alternative Fuel ◽  
Hot Water ◽  
Outer Tube ◽  
Adsorption Method ◽  
Fixed Bed Column ◽  
Column Temperature ◽  
Ethanol Ethanol

<p><strong><em>Abstract: </em></strong><em>Bioethanol is one of renewable energy source</em><em>. One example of the use of ethanol as an alternative fuel: a mixture of gasoline and alcohol (&gt;99%) called Gasohol for gasoline fuel substitute.One method of drying </em><em>ethanol is adsorption method. This study is aimed to dry ethanol (ethanol concentration&gt; 99%) or  fuel grade as an alternative fuel by adsorption method in a fixed bed column with  adsorbent silica gel. Dry ethanol</em><em> is obtained from purifying (distillation) and dryng (adsorpstion).The drying process begins with the process of refining ethanol from fermentation </em><em>±</em><em>95% continued to ethanol distillation process until the concentration dries in fixed bed column. This tool consists of: a fixed bed column (adsorber column), ethanol bait container (stokpot), electric stove, a condenser and adsorber to the condenser connector. Adsorber column consists of the adsorbent tubes with a diameter of 3.6 cm and, tube-in adsorber with a diameter of 3.8 cm, the outer tube adsorber with a diameter of 6cm and 40 cm high. Adsorber column is equipped with a heating jacket is water-tube that is placed between inner and outer tube-adsorber. Ethanol feed is heated in ethanol bait traps using electric stove and heater temperature is maintained at a temperature of </em><em>±</em><em>80ºC. Ethanol vapor is then flowed into the fixed bed column containing the adsorbent silica gel (</em><em>±</em><em>200 gr) which have been dried.Adsorber column temperature is maintained by running hot water in the jacket heater with a temperature of </em><em>±</em><em>78ºC. </em><em>Drying of ethanol is run for 120 minutes. Ethanol vapor output from the adsorber column is condensed into liquid ethanol through the condenser. The output of ethanol from the condenser is collected and analyzed using picnometer ethanol content.</em><em></em></p><p><strong><em> </em></strong><strong><em>Keywords: </em></strong><em>Adsorption,</em><em> Distillation,</em><em> Ethanol, </em><em>Fixed Bed Column,</em><em> Silica Gel</em></p>

Sorption Drying of Soybean Seeds with Silica Gel in a Fluidized Bed Dryer

2008 ◽  
Vol 4 (6) ◽  
Author(s):  
Jingsheng Ye ◽  
Qiaojun Luo ◽  
Xiaolan Li ◽  
Qing Xu ◽  
Zhanyong Li
Keyword(s):  
Fluidized Bed ◽  
Silica Gel ◽  
Fixed Bed ◽  
Soybean Seeds ◽  
Mass Ratio ◽  
Gas Velocity ◽  
Moisture Concentration ◽  
Fluidized Bed Dryer ◽  
Solid Adsorbent ◽  
Low Humidity

Soybean seeds were contacted with silica gel in a fluidized bed, where mass transfer is driven by moisture concentration gradient. It has the advantage of well-mixing the solid adsorbent (silica gel) with the material being dried (soybean seeds) in fluidization state, and thus the dried seeds quality could be improved since they are in a uniform environment of low humidity. The drying kinetics was compared under different mass ratios and fluidization conditions. The drying rate was improved with the gas velocity and mass ratio of silica gel. A scheme of sorption drying in a hybrid process of fluidized/fixed bed is proposed in the viewpoint of energy efficiency and product quality.

Mechanisms by Which Pentane and Hexane Adsorb on Silica Gel

1966 ◽  
Vol 6 (02) ◽  
pp. 166-174 ◽  
Author(s):  
H.O. McLeod ◽  
J.M. Campbell
Keyword(s):  
Mass Transfer ◽  
Silica Gel ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Fixed Bed ◽  
Transfer Coefficients ◽  
Constant Length ◽  
Adsorbate Concentration ◽  
Transfer Zone ◽  
Effluent Curve

Abstract Data analysis of pentane and hexane adsorption from natural gas in a fixed bed of silica gel shows that constant length mass transfer zones form, the curvature of the adsorption isotherm controls the growth of the mass transfer zone and surface diffusion of molecules inside the silica gel particle controls the mass transfer rate. Curvature of the hexane isotherm is more than the curvature of the pentane isotherm. Because of this curvature the hexane adsorption zones reached a constant length. In contrast, the pentane adsorption zones were always increasing in length during each run. A procedure was developed to obtain correct mass transfer coefficients using effluent curve slopes. These transfer coefficients increase with the amount of hydrocarbon adsorbed on the silica gel particle. The characteristic shape of the hexane effluent curves also show that molecular diffusion inside the silica gel particle controls the adsorption rate of pentane and hexane. Introduction The purpose of this study was to determine the mechanisms that control the dynamic adsorption of hydrocarbons from a natural gas onto silica gel. Before one can deal effectively with multicomponent adsorption, the transfer mechanisms by which a single hydrocarbon component is adsorbed from the gas stream must be defined. Two principal investigations of this system have been published and indicate that diffusion through the gas around the particle controls the adsorption rate. Some of the experimental observations in each study either do not support this transfer mechanism or are inconsistent with the mathematical model used in analysis. In this study surface diffusion of molecules inside the particle controls the mass transfer rate of pentane and hexane. This mechanism is indicated by the effluent curve shape for a constant length transfer zone and by the variation of the mass transfer coefficient with concentration of the adsorbed hydrocarbon. THEORY AND DEFINITIONS-MATHEMATICAL MODELS Mathematical solutions for the isothermal adsorption of a trace component from a carrier gas are derived from three relationships: the mass balance or continuity equation, the equilibrium relationship between the gas and solid phases, and a mass transfer rate equation. The transfer rate is proportional to the adsorbate concentration gradient within either the gas or solid phase. Mathematical solutions of these equations usually give the adsorbate concentration as a function of time and distance from the bed inlet. That part of the bed in which the adsorbate concentration changes from a maximum to a minimum value is called the transfer zone. This transfer zone is directly related to a plot of the effluent concentration vs time which has a characteristic S-shape. This general shape is determined by the continuity equation and occurs in many processes of diffusional transfer. EQUILIBRIUM ADSORPTION ISOTHERMS Different mathematical models of fixed bed adsorption occur mainly because different equilibrium adsorption isotherms are assumed. Eq. 1 describes the amount of hydrocarbon adsorbed as a function of the amount of hydrocarbon in the gas phase at a constant temperature: ........................................(1) There are two main models which describe the separation of a trace component in a fixed bed. Model A assumes a linear isotherm (r = 1); Model B assumes a favorably curved isotherm (r is less than 1). SPEJ P. 166ˆ

Sign in / Sign up

Export Citation Format

Share Document