Adsorption systems controllable costs

Compression costs are significant in large-scale adsorption systems for gases thus, pressure drop is critically important since it controls compression costs. A resonable gas velocity is 100 ft/min tSeider et al.. 20091. Pressure drop can be calculated from well-known correlations for flow in packed beds. For example, the pressure drop in a packed bed of rigid particle in laminar flow is tBird et al.. 1960 ... 

Other Potential Adsorbents. While activated carbon is the most widely used adsorbent, in the past 10 years considerable attention has been directed towards low-cost biosorbents. Activated carbon is expensive, and an alternative inexpensive adsorbent could drastically reduce the cost of an adsorption system. Many waste or naturally occurring materials have been investigated to assess their suitability. For water pollution control, the use of low-cost natural materials for the removal of copper has been studied for several materials. Other potential sorbents include peat, anaerobically digested sludge, kaolin and montmorillonite clay, treated bagasse, treated acacia bark, treated laurel bark and treated techtona bark, fly ash, Penicillium spinulosum, dyestuff-treated (Red) rice hulls and dyestuff-treated (Yellow) rice hulls, resins moss Catymperes delessertii Besch, water hyacinth (Eichomia crassipes), Rhizopus arrhizus, Cladosporium resinae and Penicillium italicum, tea leaves, amorphous iron hydroxide, and activated carbon. 

The cornerstone premise is that the vapor adsorption system is simply one of many pollution control systems on the site, such as fume scmbbers, biological treatment plants, and landfills. Seldom is a book-kept cost sheet developed for these systems. In that case ... 

The reduced adsorption capacity at ORVR vapor generation rates requires increased efficiency in the canister design, in order to limit the effect on cost and performance of the evaporative control system. 

Modification of silica gel with volatile or gaseous compounds is performed in the vapour phase. Industrial-scale reactors and laboratory scale gas adsorption apparatus have been used. In the industrial field, fluidized bed and fluid mill reactors are of main importance. In fluidized bed reactors,82 the particles undergo constant agitation due to a turbulent gas stream. Therefore, temperatures are uniform and easy to control. Reagents are introduced in the system as gases. Mass transport in the gas phase is much faster than in solution. Furthermore, gaseous phase separations require fewer procedural steps than solution phase procedures, and may also be more cost-effective, due to independence from the use and disposal of non-aqueous solvents. All these advantages make the fluidized bed reactors preferential for controlled-process industrial modifications. 

The metals content of an aqueous waste stream can be substantially decreased by complexation or adsorption methods and the recovered metal used to offset a part of the treatment costs [82]. Unexpended hypochlorite can also be neutralized by contacting this stream, in the correct proportions, with spent scrubber liquor from sulfur dioxide emission control systems (Eq. 5.35). 

If one s view is that the adsorption unit is a stand-alone operating system, where its manager is knowledgeable about and controls aU costs, then —... 

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