HCl Removal and Chlorine Distribution in the Mass Transfer Zone of a Fixed-Bed Reactor at High Temperature

The rising CO2 concentration has prompted the quest of innovative tools to reduce its effect on the environment. A comparative adsorption study using sustainable low-cost date pits-derived activated carbon and molecular sieve has been carried out for CO2 separation. The adsorb ents were characterized for surface area and morphological properties. The outcomes of flow rate, temperature and initial adsorbate concentration on adsorption performance were examined. The process effectiveness was investigated by breakthrough time, adsorbate loading, efficiency, utilized bed height, mass transfer zone and utilization factor. The immensely steep adsorption response curves demonstrate acceptable utilization of adsorbent capability under breakthrough condition. The adsorbate loading 73.08 mg/g is achieved with an 0.938 column efficiency for developed porous activated carbon at 298 K. The reduced 1.20 cm length of mass transfer zone with enhanced capacity utilization factor equal 0.97 at 298 K with Cin = 5% signifies better adsorption performance for date pits-derived adsorbent. The findings recommend that produced activated carbon is greatly promising to adsorb CO2 in fixed bed column under continuous mode.

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CO2 sorption from a mixture of N2/CO2 using an activated carbon and silica gel: equilibrium, breakthrough and mass transfer zone

Global NEST Journal ◽

10.30955/gnj.003166 ◽

2020 ◽

Keyword(s):

Mass Transfer ◽

Partial Pressure ◽

Flow Rate ◽

Feed Rate ◽

Fixed Bed ◽

Feed Flow Rate ◽

Utilization Factor ◽

Mass Transfer Zone ◽

Maximal Capacity ◽

Transfer Zone

<p>The temperature, feed rate, length of mass transfer zone, utilization factor and partial pressure are the parameters considered for fixed bed sorption of CO2 from N2/CO2 mixture. The breakthrough time relies strongly on the temperature and feed rate. The prolonged breakthrough and saturation times have been realized for AC. The response curves of AC are vastly steep signifying the maximal utilization of bed capacity at the breakpoint. In general, the length of MTZ increases with raised temperature and feed flow rate. The capacity utilization factor reduces with raised temperature and feed flow rate. A utilization factor of 0.919 was determined for AC. The maximal capacity for CO2 reduces significantly with an increased temperature. The maximal capacities of 32.99 gm CO2/Kg was determined at a temperature of 298 K for AC. The capacity improves considerably with CO2 partial pressure and AC exhibited higher adsorption capacity compared to SG. The capacity improves considerably with increased feed rates and maximal capacity of 39.14 g CO2/Kg adsorbent was determined for AC at the feed rate of 8.33 x10-3 m3/sec. Owing to higher sorption capacity and utilization factor, the AC may be used for economical separation of CO2 from N2/CO2 mixture</p>

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Removal of Cu(II) by Fixed-Bed Columns Using Alg-Ch and Alg-ChS Hydrogel Beads: Effect of Operating Conditions on the Mass Transfer Zone

Polymers ◽

10.3390/polym12102345 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2345

Author(s):

Ilse Paulina Verduzco-Navarro ◽

Nely Rios-Donato ◽

Carlos Federico Jasso-Gastinel ◽

Álvaro de Jesús Martínez-Gómez ◽

Eduardo Mendizábal

Keyword(s):

Mass Transfer ◽

Flow Rate ◽

Linear Regression Analysis ◽

Fixed Bed ◽

Operating Conditions ◽

Column Height ◽

Thomas Model ◽

Hydrogel Beads ◽

Mass Transfer Zone ◽

Transfer Zone

The removal of Cu(II) ions from aqueous solutions at a pH of 5.0 was carried out using fixed-bed columns packed with alginate-chitosan (Alg-Ch) or alginate-chitosan sulfate (Alg-ChS) hydrogel beads. The effect of the initial Cu(II) concentration, flow rate, pH, and height of the column on the amount of Cu removed by the column at the breakpoint and at the exhaustion point is reported. The pH of the solution at the column’s exit was initially higher than that at the entrance, and then decreased slowly. This pH increase was attributed to proton transfer from the aqueous solution to the amino and COO− groups of the hydrogel. The effect of operating conditions on the mass transfer zone (MTZ) and the length of the unused bed (HLUB) is reported. At the lower flow rate and lower Cu(II) concentration used, the MTZ was completely developed and the column operated efficiently; by increasing column height, the MTZ has a better opportunity to develop fully. Experimental data were fitted to the fixed-bed Thomas model using a non-linear regression analysis and a good correspondence between experimental and Thomas model curves was observed.

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HCl Removal Using Calcined Ca–Mg–Al Layered Double Hydroxide in the Presence of CO2 at Medium–High Temperature

Catalysts ◽

10.3390/catal10010022 ◽

2019 ◽

Vol 10 (1) ◽

pp. 22

Author(s):

Wei Wu ◽

Yuanfeng Wu ◽

Tongwei Wang ◽

Decheng Wang ◽

Qinyang Gu ◽

...

Keyword(s):

High Temperature ◽

Flue Gas ◽

Fixed Bed ◽

Co2 Concentration ◽

Metal Chloride ◽

Fixed Bed Reactor ◽

Waste Incinerators ◽

Hcl Removal ◽

Double Hydroxide ◽

Double Hydroxides

This present work aimed to investigate the influence of CO2 on HCl removal using calcined Ca–Mg–Al layered double hydroxides (CaMgAl-LDHs) at medium–high temperature (400–800 °C) in a fixed-bed reactor. It was revealed that a moderate CO2 concentration (~6%) in the flue gas of the municipal solid-waste incinerators could reduce the HCl capacity of the CaMgAl-layered double oxides (CaMgAl-LDOs). The highest capacity for HCl removal was observed over the CaMgAl-LDOs at 600 °C. However, sintering was also detected when the reaction temperature was below the calcination temperature (600 °C). Moreover, the decreasing HCl adsorption capacity of CaMgAl-LDOs was attributed to the existence of CO2 in the flue gas, which could efficiently inhibit the decomposition of carbonates as well as the conversion into metal chloride during the HCl removal process.

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Application of analytical solution of advection-dispersion-reaction model to predict the breakthrough curve and mass transfer zone for the biosorption of heavy metal ion in a fixed bed column

Process Safety and Environmental Protection ◽

10.1016/j.psep.2020.02.018 ◽

2020 ◽

Vol 137 ◽

pp. 58-65 ◽

Cited By ~ 3

Author(s):

Ronbanchob Apiratikul

Keyword(s):

Heavy Metal ◽

Mass Transfer ◽

Breakthrough Curve ◽

Metal Ion ◽

Fixed Bed ◽

Reaction Model ◽

Fixed Bed Column ◽

Advection Dispersion ◽

Mass Transfer Zone ◽

Transfer Zone

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Modeling of aerated upflow fixed bed reactors for nitrification

Water Science & Technology ◽

10.2166/wst.1999.0193 ◽

1999 ◽

Vol 39 (4) ◽

pp. 85-92 ◽

Cited By ~ 7

Author(s):

J. Behrendt

Keyword(s):

Mathematical Model ◽

Mass Transfer ◽

Liquid Phase ◽

Gas Phase ◽

Fixed Bed ◽

Fixed Bed Reactor ◽

Bulk Liquid ◽

Initial Value ◽

Fixed Bed Reactors ◽

Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

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