Design and Control of Reactive Divided Wall Column for Hydrolysis of Methyl Acetate System

• Main Authors: Chih-Chun Hsu, 許智鈞
• Other Authors: Hsiao-Ping Huang 黃孝平
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/10224356186582882288

碩士 === 國立臺灣大學 === 化學工程學研究所 === 96 === Because the price of the crude oil is arising constantly, the exploitation of energy saving becomes one of the recent focuses in research. Utilizing integrated multi-functional unit to replace some single function units is one effective approach toward this goal. Reactive distillation column (RD) and divided wall column (DWC) are examples of such integration. A further integration of RD and DWC is thus motivated and is called reactive divided wall column (RDWC). The methyl acetate hydrolysis process with RDWC design was first proposed by Sander (2007). However, their work was aimed to illustrate that the concept of RDWC could be physically feasible for industry. From their research, the major products (i.e. methanol and acetic acid) are not as pure as the industrial grade. To overcome this deficiency, the design of RDWC aimed to high quality products and the possible energy savings achievable are studied. In this thesis, traditional RD configurations which contains one RD column and possible separation distillation columns for methyl acetate hydrolysis is studied. In these configurations, RD top condenser contains 10 times catalyst than reactive tray and has total reflux to improve the methyl acetate conversion. Except the methyl acetate, the acetic acid, methanol, and excess reactant water are drawn from the RD bottom and fed into the separation distillation columns. It is found that although the above-mentioned configurations can achieve high product specifications, it needs much more reboiler duty and total annual cost. To decrease the energy consumption and capital cost reduction, the above process is integrated to a RDWC configuration. By simulation, it proves that this RDWC can be an effective design. Compared with the original configuration, the original RD reboiler is removed. From this RDWC design, all energy required is provided by the reboiler of the second column. The resulting RDWC can reduce 45 % energy demand and 25 % total annual cost. It is observed that, to make this major saving possible, this RDWC avoids the remixing effect that used to take place is the original RD bottom.