Definition and Analysis of Intrinsic and Extrinsic Irreversibility － Naphtha Process
| Autor: | Shang-Chih Chuang, 莊尚智 |
|---|---|
| Rok vydání: | 2001 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 89 This thesis proposes a two-level idealization, the reversible operation and thermodynamic equilibrium operation, for characterizing the energy utilization of different operations. The exergy losses corresponding to the deviations from both idealizations are defined as intrinsic exergy loss and extrinsic exergy loss, respectively. The deviation from reversible idealization results from the limitations of configuration design, and the deviation from thermodynamic equilibrium idealization results from the rate limitations of transport phenomena.This thesis provides the definitions, analysis methodology and case analysis results of intrinsic and extrinsic exergy losses for basic operations, complex operations and an overall process. The basic operations include temperature change, pressure change and concentration change operations. The complex operations include plate type and packed type simple distillation columns. For simple distillation column, the intrinsic and extrinsic exergy losses are defined for the overall column level and the individual stage level. For the overall process, the product recovery and purification process of an ethylene plant is analyzed.The analysis allows the judge of the relative significance between intrinsic exergy loss and extrinsic exergy loss. Besides, the direction of improvement should be on the configuration design limitation or transport phenomena rate limitation can be pinpointed.For the plate type de-ethanizer column, the intrinsic exergy loss is more significant. The effects of using different number of stages, using an inter-reboiler and modifying weir height are examined. For the packed type Benzene-Toluene distillation column, both intrinsic and extrinsic exergy losses are important.For the ethylene plant product recovery and purification process, heat exchange units deserve highest attention for improvements, in particular, for the configuration design of the feed pre-cooler and condenser of the de-methanizer and for the heat transfer rate of the reboiler of the C2 splitter. For distillation operations, the mass transfer rate of the de-methanizer should be focused for improvements. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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