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作者 Emamipour, Hamidreza
書名 Experimental and numerical evaluation of electrothermal-swing adsorption for capture and recovery or destruction of organic vapors
國際標準書號 9781124314884
book jacket
說明 141 p
附註 Source: Dissertation Abstracts International, Volume: 71-12, Section: B, page:
Adviser: Mark J. Rood
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2010
The Vapor Phase Removal and Recovery System (VaPRRS or ESA-R)) was evaluated for possible improvements. An automated bench-scale adsorption device using activated carbon fiber cloth (ACFC) was designed and built to study effects of select independent engineering parameters on the ability of the system to capture and recover an organic vapor (e.g., methyl ethyl ketone, MEK) from air streams. Factors that can increase the adsorbate liquid recovery with low energy costs were investigated using sequentially designed sets of laboratory experiments. Initially, the screening experiments were conducted to determine significant factors influencing the energy efficiency of the desorption process. It was determined that "concentration of organic vapor", "packing density", and "maximum heating temperature" are significant factors while "nitrogen flow" and "heating algorithm" are insignificant factors in the ranges of values that were evaluated. Experimental data provided from this work were then used as inputs by Kaldate (2005) to complete a response surface methodology using Central Composite Design to optimize the operation of the ESA system in a region where efficient liquid recovery can be achieved. These results were used by Kaldate (2005) to reduce the amount of power applied per unit mass of ACFC in the vessel and provide a scale-up model of the ESA system
A new concentration controlled desorption device, known as ESA-Steady State Tracking (ESA-SS) desorption, was also designed and built as a bench-scale laboratory device as part of this research. This new system was demonstrated to operate over a wide range of conditions (i.e., type of organic vapor, concentration of organic vapor, ratio of desorption/adsorption cycle gas flow rates, fixed and dynamic desorption concentration set-points, constant and variable inlet concentration of organic vapor, batch and cyclic modes, and with dry and humid gas streams). It was shown that concentration of organic vapor that is generated during regeneration cycles can readily be controlled at concentration set-points for three organic compounds (MEK, acetone, and toluene). The average absolute errors (AAEs) were < 5% when comparing the set-point and the measured outlet vapor concentrations. This is the first time that such performance has been demonstrated and this performance is not possible with other current technologies. Such capability of the system allows a secondary control device to be optimized for select constant concentrations and much lower gas flow rates (e.g., 5% of the gas flow rate during the adsorption cycle) that is not possible without such pretreatment
An ESA-Concomitant Adsorption and Desorption (CAD) system was also developed as part of this research to readily control its outlet organic vapor concentration as the entire inlet gas stream passes through the CAD system. This bench-scale system adsorbed organic vapor from a gas stream and simultaneously heated the adsorbent using direct electrothermal energy to desorb the organic vapor at user-selected set-point outlet concentrations. CAD achieved a high degree of concentration stabilization with a mean relative deviation between set-point concentration and measured outlet vapor concentration of 0.3% to 0.4%. The CAD system was also evaluated to treat a humid gas stream (inlet relative humidity = 85%) that contained a variable organic vapor concentration. CAD operated successfully at high inlet relative humidity conditions because the water vapor did not adsorb but penetrated through the adsorbent because of local warming of the adsorbent
A fundamental mathematical model for simulation of ESA was also developed and evaluated. The model consists of: (a) material balances for organic vapors in the adsorption vessel and (b) energy balances for the adsorbent, carrier gas, vapor, and fittings. The model predicts outlet vapor concentrations, temperature profiles, power requirements, voltage requirements, and current requirements for ESA desorption cycles. The model is very helpful in the initial stages of design of an ESA system to reduce cost and time and to more effectively evaluate experimental results pertaining to energy and material balances. (Abstract shortened by UMI.)
School code: 0090
Host Item Dissertation Abstracts International 71-12B
主題 Atmospheric Chemistry
Environmental Health
Chemistry, Organic
Engineering, Civil
0371
0470
0490
0543
Alt Author University of Illinois at Urbana-Champaign
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