化学を学ぶ学生のための化学工学基礎
大庭

武 泰

分離技術会

は じ め に

本書は，大学の化学や生物に関する学科(応用化学科，生物工学科など)，高専の工業化学科などで化学を学んでいて初めて化学工学を学習する学生を対象としています．化学工学とは，さまざまな化学製品を製造する際に必要な学問ですが，現在では「化学工学的な手法」と呼ばれる考え方が化学にとどまらず幅広い領域で活用されています．「化学工学的な手法」は明確に定義されたものではありませんが，物質の出入りや熱の出入りを正確に扱うことから始まり，化学反応などの対象を数式で表したり，複数の要素をまとめて目的を達成する装置をつくることまで含みます．
本書の構成は，量を正しく扱うための単位の話から始め，物質とエネルギーの出入りを定量的に扱う方法，さらにそれらの具体例として蒸留とガス吸収を解説します．また，流体の流れと熱の伝わり方について説明し，最後に物質の生産においては必要不可欠な粉粒体(粉体)の分離の基礎について扱うことで，化学工学における分離の基礎の修得を目的としています．また，それぞれの解説ではできる限り簡便な図を用いた説明をすることでイメージをつかみやすくし，学習者自らが図を描けるようになることを目標としています．
解説の後には例題とその解説を具体的に示し，さらに演習問題をこなしていくことで，実践する方法を身につけられるようにしてあります．
2019．9大庭武泰

目次

１．化学工学とは ···························································

1

化学工学と扱う範囲 ···············································

1

化学工学とその考え方 ············································

1

化学工学を理解するための本書の利用方法 ·················

2２．単位系・次元・濃度など，物理量の扱い方 ····················

3SI(国際単位系)······················································

3

数値や単位，変数の表し方 ······································

3

複雑な単位を理解しよう ·········································

5単位の換算方法 ·····················································

5古い単位について ···············································

6温度の単位換算について ······································

9単位を使って現象をとらえる ···································

9無次元数と次元解析とその限界 ·····························

11

３．物質収支と熱収支 ·····················································

13

システムを図で表す ···············································

14

物質収支 ······························································

16

化学反応を含まないシステム ································

17

ループ(リサイクル流れ)を含むシステム ·················

19

化学反応を含むシステム ······································

24

原子の個数での物質収支も活用しよう ····················

27

不活性物質の活用 ···············································

29

熱収支 ·································································

29

エネルギーの表し方 ············································

30

物質の持つエンタルピーの計算方法 ·······················

32

化学反応プロセスのエンタルピー変化 ····················

34

物質収支・熱収支の応用 ·········································

36

蒸留とは ···························································

36

物質の蒸気圧の違い ·········································

37

蒸留の操作 ·····················································

39

装置の改善 ·····················································

40

蒸留塔の構造 ··················································

42

蒸留塔全体の物質収支 ······································

42

蒸留塔の熱収支 ···············································

43

ガス吸収とは ·····················································

44

物質の溶解度の違い ·········································

44

ガス吸収の操作 ···············································

45

ガス吸収の装置 ···············································

46

充填塔の構造と物質の流れ ································

47

ガス吸収塔(充填塔)の物質収支 ··························

47

ガス吸収塔(充填塔)の熱収支 ·····························

48

４．分離操作 ·································································

49

蒸留 ····································································

49

物質の蒸気圧を数式で表す ···································

49

ラウールの法則から蒸気圧を示す式を得る ···········

51

ラウールの法則から気液平衡曲線の式を得る ········

52

単蒸留を式で表す ···············································

54

単蒸留の物質収支 ············································

54

蒸留塔を式で表す ···············································

57

物質収支式の見える化 ······································

61

蒸留塔の設計情報を得る ···································

66

段数の最小値，最大値 ······································

69

ガス吸収 ······························································

71

ガス吸収塔の内部構造 ·········································

71

ガス吸収塔でのガス吸収の進み方 ··························

72

充填塔の物質収支 ···············································

74

物質収支の見える化 ············································

76

ガス吸収塔の設計情報を得る ································

79

５．流動と伝熱の基礎 ·····················································

85

流動 ····································································

85

体積流量，質量流量，平均流速の関係 ····················

86

連続の式 ···························································

87

流体の持つエネルギー ·········································

88

層流と乱流 ························································

92

伝熱 ····································································

93

伝導伝熱 ···························································

94

材質の異なる板を伝わる熱 ···································

95

６．粉体(粉粒体)の基礎 ··················································

98

粉体の特徴 ···························································

98

粒子の大きさ ························································

99

粉体の大きさ ························································ 100
粒子の大きさの分布 ············································ 100
粒子を分ける方法 ·················································· 101
重力で分ける方法 ··············································· 101
重力を用いた分離・分級装置 ····························· 103
重力分級機の設計 ············································ 103
遠心力で分ける方法 ············································ 106

サイクロンの構造 ············································ 107
サイクロンでの分離の仕組み ····························· 108
サイクロンの設計 ············································ 110