Activated carbon bed

Some natural gases have also been found to contain mercury, which is a reformer catalyst poison when present in sufftciendy large amounts. Activated carbon beds impregnated with sulfur have been found to be effective in removing this metal. 

Process and environmental air is compressed and passed through activated beds to reduce air emission levels to <5 ppm. Process wastewater is air stripped to remove CCl. The solvent containing air is also passed through the activated carbon beds. The total air flow through the beds averages about 3965 mVmin (140,000 SCFM). 

In this example, the one liter canister is designed as a cylinder with a length-to-diameter (L/D) ratio of five. The vapor feed stream to the canister is a 50/50 mixture of n-butane and air, and the inlet flow rate is set at 40 grams per hour of n-butane. The curves in the Fig.9 show that break through occurs shortly after the 100 minute point in the load. Up to break-through, the activated carbon bed has adsorbed about 65 grams of HC. 

Shah, G. C. Improve Activated Carbon Bed Adsorber Operations, Hydrocarbon. Processing 71 (1992) no. 11, pp. 61-63. 

Activated carbon An adsorption filter that makes use of an activated carbon bed to remove odors and various gases from a ventilating or gas cleaning system. 

Chen et al. [70] suggested that temperature gradients may have been responsible for the more than 90 % selectivity of the formation of acetylene from methane in a microwave heated activated carbon bed. The authors believed that the highly nonisothermal nature of the packed bed might allow reaction intermediates formed on the surface to desorb into a relatively cool gas stream where they are transformed via a different reaction pathway than in a conventional isothermal reactor. The results indicated that temperature gradients were approximately 20 K. The nonisothermal nature of this packed bed resulted in an apparent rate enhancement and altered the activation energy and pre-exponential factor [94]. Formation of hot spots was modeled by calculation and, in the case of solid materials, studied by several authors [105-108],... 

An initially clean activated carbon bed at 320 K is fed a vapor of benzene in nitrogen at a total pressure of 1 MPa. The concentration of benzene in the feed is 6 mol/m3. After the bed is uniformly saturated with feed, it is regenerated using benzene-free nitrogen at 400 K and 1 MPa. Solve for both steps. For simplicity, neglect fluid-phase accumulation terms and assume constant mean heat capacities for stationary and fluid phases and a constant velocity. The system is described by... 

In the most recent plants, the electrolysis is performed in a membrane cell while the chemical step is carried out by allowing the chromic acid to trickle through a column of solid anthracene. The product - anthraquinone - is also insoluble in the aqueous acid so that the organic conversion is effectively completed in the solid state. The reaction goes to completion provided the particle size of the anthracene falls within a suitable range. The spent redox reagent is then passed through an activated carbon bed to remove traces of... 

Abstract To design an adsorption cartridge, it is necessary to be able to predict the service life as a function of several parameters. This prediction needs a model of the breakthrough curve of the toxic from the activated carbon bed. The most popular equation is the Wheeler-Jonas equation. We study the properties of this equation and show that it satisfies the constant pattern behaviour of travelling adsorption fronts. We compare this equation with other models of chemical engineering, mainly the linear driving force (LDF) approximation. It is shown that the different models lead to a different service life. And thus it is very important to choose the proper model. The LDF model has more physical significance and is recommended in combination with Dubinin-Radushkevitch (DR) isotherm even if no analytical solution exists. A numerical solution of the system equation must be used. 

In the second process, the caffeine-loaded CO2 flows through an activated-carbon bed and the caffeine is adsorbed. Usually the activated carbon is recycled by heat treatment up to 600°C and the caffeine is destroyed. 

Disinfection of water is used to destroy bacteria. However, RO membranes are sensitive to oxidizers so they must be removed before entering the membranes. Active-carbon beds are sometimes used to remove traces of organic matter together... 

P. Lodewyckx and E. F. Vansant, Influence of humidity on adsorption capacity from the Wheeler-Jonas model for prediction of breakthrough times of water immiscible organic vapors on activated carbon beds, Am. Ind. Hyg. Assoc. J. 60, 612-617 (1999). 

O. Busmundrud, Vapour breakthrough in activated carbon beds, Carbon 31, 279-286 (1993). 

Brief Process Description of Davy s Latest High Efficiency Design. Natural gas is desulfurized over an activated carbon bed or zinc oxide to remove sulfur below 0.2 ppm, suitable for natural gas reforming. 

The application of SPE has partially eliminated the above problems, particularly in the case of arsenic concentration in water samples [123]. SPE delivers better selectivity than LEE because it can be used to sequentially elute compounds from the activated carbon bed, and to separate inorganic compounds of As(III) and As (V), as well as the phenyl (PAS) and dimethyl (DMA) derivatives of arsenic (V) acid [124]. The extraction process is short, which is why it is possible to directly coimect the SPE module with the ICP MS detector [125]. Whenever modified silica is used, arsenic recovery is low (even below 50 %) owing to the formation of hydrogen bonds between the substances being separated and silanol groups [114, 126, 127]. 

Example 8.8 A wastewater containing 25 mg/L of phenol and having the characteristic breakthrough of the previous example is to be treated by adsorption onto an activated carbon bed. The flow rate during the breakthrough experiment is 0.11 mVs this is equivalent to a surficial velocity of 0.0088 m/s. The XIM ratio of the bed for the desired effluent of 0.06 mg/L is 0.02 kg solute per kg carbon. If the flow rate for design is also 0.11 mVs, design the absorption column. Assume the influent is introduced at the top of the bed. The packed density of the carbon bed is 721.58 kg/ml... 

Example 17.18 A total flow of 25,000 m /d is to be dechlorinated after disinfection using chlorine. An activated carbon bed is to be used for dechlorination. If the total residual chlorine (TRC) is 0.5 mg/L, how many kilograms of activated carbon are lost from the bed per day ... 

Pr P., Delage F. and Le Cloirec P., Modeling the exothermal nature of V.O.C adsorption to prevent activated carbon bed ignition. Fundamentals of adsorption 7, K. Kaneto, H. Kanoh, Y. Hanzawa Editors, IK International, Chiba, Japon, (2001) pp. 700 -707. 

Delage F., Pr P., and Le Cloirec P., Mass transfer and warming during adsorption of high concentrations of VOCs on an activated carbon bed experimental and theoretical analysis. Environ. Sci. Technol., 34 (22) (2000). pp. 4816-4821... 

In the adsorption experiment of binary mixture (Figure 4), breakthrough time of the activated carbon bed was longer than the zeolite SA bed, moreover the zeolite SA bed had more tailing effect than the activated carbon bed. 

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