共沸蒸留塔の特性

Characteristics of Azeotropic Distillation Column

吉田 英人

頼実 正弘

石油学会誌

ベンゼン, エタノール, 水系に対する共沸蒸留計算を緩和法を用いて行い, 種々の操作条件に対して分離数および熱力学的効率の両面から最適操作条件を検討した。気液モル流量比に関しては第1塔は1.3以下, 第2塔は1.2以下が望ましい。また塔内圧力が上昇すると, エタノールと水の分離が悪くなり, 分離数および熱力学的効率が低下する。さらにベンゼン相と水相の分離を良くするために, デカンターに水を供給した場合, エタノールと水の分離は良くなるが, リボイラー部での必要熱量が増加すること等の新しい知見を得た。

The relaxation method was used for azeotropic distillation calculations. For the Benzene-Ethanol-Water system, various operating conditions were examined by use of thermodynamic efficiency and separation number.

For vapor-liquid calculations NRTL Eq. was used, and Eq. (3) was used for separation number calculations. Eqs. (4), (5), (6) were used for thermodynamic efficiency calculations. A schematic drawing of azeotropic distillation column is shown in Fig. 1. It was found from Figs. 3, 4, 5 that the ratio of liquid to vapor flow rate for the first column should be less than 1.3. From Figs. 6, 7, 8, it was also found that the ratio of liquid to vapor flow rate for the second column should be less than 1.2. Fig. 9 shows that both the thermodynamic efficiency and separation number were maximized when the temperature of the feed was in the boiling condition. The maximum thermodynamic efficiency was about 0.07. Figs. 10, 11, indicated that as the pressure of the column decreased, the separation of ethanol and water improved. Fig. 11, showed that as the pressure increased, the thermodynamic efficiency decreased. Fig. 12 shows the relation between mole fraction of bottom liquid and water feed rate to the decanter. It indicated that as the water feed rate to the decanter increased, the separation of bottom liquid in the second column improved. But from Fig. 13, it was observed that the greater the water feed rate to the decanter was the greater the reboiler duty.

Azeotrope

Benzene

Distillation

Ethanol

Thermodynamic efficiency

化学工業 [ 570 ]

日本語

石油学会

Copyright (c) 1983 (社)石油学会

本文データはJournal@rchiveから複製したものである

[ISSN] 0582-4664

[NCID] AN00130954

[URI] http://www.journalarchive.jst.go.jp/japanese/jnlabstract_ja.php?cdjournal=jpi1958&cdvol=26&noissue=2&startpage=110