| Summary: | 碩士 === 國立中央大學 === 化學工程研究所 === 87 === Volatile organic compounds (VOCs) are used as solvents in the manufacture of countless products. Some prominent examples of these products included crystallized organic chemicals, printed materials, and petroleum industry. One of the most important and effective methods of controlling the emission of VOCs is the use of the adsorption process.
The primary objectives of the present work are the recovery of the methylene chloride vapor (CH2Cl2) by temperature swing adsorption (TSA) process. Activated carbon was used as an adsorbent and a volatile organic compound, and CH2Cl2 was chosen as the solvent. Air was used as a carrier gas in the adsorption step, and nitrogen gas was used as a purge gas in the regeneration step. A linear driving force mass transfer model was used, and the equilibrium relationship for the CH2Cl2 is represented by the temperature-dependent Langmuir isotherm. The pressure gradient across the bed is neglected.
In the model developed in this work, there are five partial differential equations (PDEs) for mass and energy balances within the packed bed. The PDEs were reduced to a set of ordinary differential equations (ODEs) by the method of lines technique. Using the subroutine LSODE of the ODEPACK solved the resulting sets of ODEs.
Modeling results was used to probe into the optimum procedure and study the effects of operations variables, such as each step time, heat transfer coefficient, mass transfer coefficient and purge temperature. We wish the results could provide a reference material to set up the experiment system.
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