分離技術シリーズ 22

化学プラントのプロセス設計－化学プラント工学入門－

白

石

浩 著

分 離 技 術 会

は じ め に

私たちの身の回りには，燃料，合成繊維，合成ゴム，プラスチック製品，化学肥料，医薬品，化粧品，半導体などの現代社会の快適な生活に必要不可欠な製品が多くある．これらは，化学工業によって製造・生産されたものである．
化学工業は複数の様々な化学装置(化学プロセス)が組み合わされた工場施設，
すなわち，化学プラントから構成されている．これらの化学プラントは，安定して，安全に，かつ，経済的に操業されることが必要で，その目的に適ったよ
うに，設計されている．化学プラントを設計するのに使われている知識で中核をなすのが，化学工学である．
このテキストは，化学工学を学んでいる学生向けに，化学プラントの設計に関する仕事の流れとその概要を理解し，プラント設計の仕事がどのようなもの
であるか，化学工学が実際の仕事にどのように使われているかを理解すること目的に作成している．また，実際に稼働しているプラントを例に取ったプロセス設計の演習を通じて，その理解を促進し，設計能力が身につくことを目指している．設計の基礎・原理を学ぶために，演習では専用設計ソフトウエアは使用せず，手計算で解くことを中心にしている．
なお，このテキストの作成に際し，参考文献に挙げた図書をはじめとしてその他多くの文献，ご指導を受けた緒先生・先輩方から学んだ事柄を参照させていただいた．ここに，故平田光穂教授をはじめ，それらの著者・先生・先輩
方々に深く感謝の意を表したい．また，出版にあたっては，機会を与えていた
だき，また，相談にも乗っていただいた分離技術会出版委員会委員長の小島博
光教授，校正の段階で助言を戴いた㈱化学工業社三澤忠則社長には，心から感
謝の気持ちを伝えたい．
2011 年 9 月
白

石

浩

目

次

１．化学プラント工学入門 ·······························································
1．1

化学プラントとは ·······························································

1．2

化学プラントの例としての石油精製プラントの紹介と
化学プロセスの基本構成 ·························································

1．3

化学プラントの商業化の仕事の流れ ·······································

1．4

化学プラント建設企業の仕事の流れ(プラント建設

1
1
1
8

プロジェクトの仕事の流れ)····················································· 10
1．5化学プラント工学の概要 ······················································· 11

1．5．1

化学プラント工学とは··················································· 11

1．5．2

プロジェクトマネージメント········································· 12

1．6

本章のまとめ ····································································· 17

２．化学プラント設計の要であるプロセス設計の概要 ··························· 18
2．1

プロセス設計はどのようなことを行うか？ ······························ 18

2．2

プロセス設計の作業の流れ ··················································· 19

2．3

プロセス設計に必要な知識 ··················································· 22

2．4

本章のまとめ ····································································· 24

３．蒸留の基礎 ·············································································· 25
3．1

蒸留の原理 ········································································ 25

3．2

沸点の違い ········································································ 273．3

気液平衡 ··········································································· 29

3．3．1

気液平衡関係······························································ 29

3．3．2

気液平衡の計算··························································· 32

3．4

蒸留の種類 ········································································ 36

3．4．1

単蒸留······································································· 36

3．4．2

連続蒸留···································································· 37

3．5

蒸留塔周りの物質収支・熱収支 ············································· 40

3．5．1

蒸留塔の物質収支························································ 40

3．5．2

蒸留塔の操作線··························································· 45

3．5．3

理論段数の計算··························································· 46

3．5．4

全還流と最小理論段数，及び，最小還流比······················· 48

3．5．5

蒸留塔周りの熱収支····················································· 49

3．6 本章のまとめ ······································································· 53
４．演習課題と設計の準備 ······························································· 54
4．1

課題説明 ··········································································· 54

4．2

演習課題用デザインベーシス(装置設計の要求事項) ·················· 56

4．3

プロセス設計の手順 ···························································· 57

4．4設計の準備 ········································································ 59

4．5

本章のまとめ ····································································· 62

５．プロセス設計の実際：物質・熱収支決定からプロセスフロー図作成まで ························································· 63
5．1

プロピレン精留塔装置全体の物質収支の把握 ··························· 63

5．2

プロピレン精留塔の運転圧力・温度の決定 ······························ 64

5．2．1

蒸留塔の塔頂と塔底の運転圧力・温度を決めるときの注意事項···································································· 64

5．2．2

蒸留塔の塔頂圧力・温度の決定······································ 65

5．2．3

蒸留塔の塔底圧力・温度の決定······································ 66

5．3

蒸留塔の最小理論段数と最小還流比 ······································· 68

5．3．1

最小理論段数······························································ 69

5．3．2

最小還流比································································· 71

5．4

蒸留塔の最適な段数の決定：ギリランドと平田の相関 ··············· 74

5．4．1

還流比と理論段数の関係··············································· 74

5．4．2

設計時の還流比と理論段数の決定··································· 75

5．4．3

原料供給段の決定························································ 77

5．5

蒸留塔周りの物質・熱収支 ··················································· 77

5．5．1

決定した段数の場合の物質収支と塔頂液過冷却時の還流量·· 77

5．5．2
5．6

決定した段数の場合の熱収支········································· 80

プロピレン精留塔装置のプロセスフロー図の作成と制御システムの概要 ···························································· 815．6．1

装置として必要な機器の追加········································· 81

5．6．2

制御システム······························································ 82

5．6．3

プロセスフロー図の作成··············································· 92

5．7

本章のまとめ ····································································· 93

６．プロセス設計の実際：機器の設計 ················································ 95
6．1

蒸留塔の設計 ····································································· 95

6．1．1

蒸留塔の設計因子························································ 95

6．1．2

蒸留塔塔径の決定························································ 101

6．1．3

蒸留塔の塔高の決定····················································· 108

6．1．4

スケルトン作成····························································110

6．2

受槽の設計 ·········································································110

6．2．1

受槽の役割と設計基準···················································110

6．2．2

本課題の受槽の寸法······················································111

6．3

ポンプの設計 ······································································112

6．3．1

ポンプの役割とハイドロリック収支·································112

6．3．2

ポンプの種類·······························································115

6．3．3

本課題のポンプの仕様···················································116

6．4熱交換器の設計 ·································································· 121

6．4．1

熱交換器の役割と基本式··············································· 121

6．4．2

本課題の熱交換器の寸法··············································· 125

6．5

プラントに使用する材料 ······················································ 130

6．6

機器リストの作成 ······························································· 131

6．7

用役消費量の算出 ······························································· 131

6．8

本章のまとめ ····································································· 132

７．プラントコストと経済性の評価 ··················································· 134
7．1 プラントコスト積算方法 ························································ 134
7．2 建設プロジェクトのコストの算出 ············································ 136

7．3 年間経費の算出 ···································································· 137
7．4 経済性の評価 ······································································· 138
7．5 本章のまとめ ······································································· 140
８．環境対策/省エネルギーへの取り組み············································ 141
8．1 環境問題 ············································································· 141
8．2 環境問題への化学工学の知見を活かした取り組み ······················· 143
8．3 今回の装置での省エネルギー対策の検討 ··································· 146
8．4 本章のまとめ ······································································· 149
９．テキストのまとめと復習問題 ······················································ 150
9．1 テキストのまとめ ································································· 150
9．2 復習問題 ············································································· 152
参考文献 ···················································································· 157
添付資料 ······················································································· 158
演習問題・復習問題の解答 ······························································· 169
索

引 ·························································································· 171