催化剂润湿钝化

© 2014 Paul R Robinson8
Passivation Is Like Titration 钝化类似滴定
Near equivalence point, small changes have a huge effect
Strong Acid 强酸性 (Cracking Catalyst) Strong Base (TBA) 强碱性
Bed 3 .OP 20%
Bed 3 .OP 20%
Bed 3 .OP 20%
Bed 3 .OP 10%
Bed 3 .OP 1%
.SP 69C
Bed 4 .OP 3%
Bed 4 .OP 5%
Bed 4 .OP 5%
Leabharlann Baidu
Bed 4 .OP 5%
Bed 4 .OP 10%
Bed 4 .OP 20%
Bed 4 .OP 20%
Time O Start oil 10 min Oil hits GPH 80C Bed 1 .OP 15% 14 min Oil hits B1 Out 80C Bed 1 .OP 15% 18 min Oil hits B2 Out 80C Bed 1 .OP 10% 26 min Oil hits B3 Out 80C Bed 1 .OP 1% 30 min Oil hits B4 Out 80C Bed 1 .OP 1% 34 min Oil hits B5 out 80C Bed 1 .OP 1% 38 min T wave ends 80C Bed 1 .OP 1% .SP 80C
Bed 4 .OP 1%
.SP 66C
Bed 5
Bed 5
Bed 5
Bed 5
Bed 5
Bed 5
Bed 5
Bed 5
© 2014 Paul R Robinson7
Passivation of Cracking Catalysts 催化剂钝化
• Hydrocracking requires acidic catalysts 裂化剂需要酸性催化剂 • Cracking may begin at 315˚C 裂化可能在315C开始 • But catalyst activation requires 345˚C -- >30˚C higher than cracking 但裂化剂活化需要在345C进行，大于裂化温度30C • Without passivation, cracking catalysts cannot be activated completely and safely • 没有钝化，裂化剂不能安全的完全活化 • Acidity is neutralized with passivation agents 酸性会被钝化剂中 和 • Feed organic nitrogen 有机氮油 • Ammonia 氨 • Aliphatic organic amines such as tri-n-butylamine (TBA) TBA
Reactions and Heat Release 反应和放热
Reaction Type Minimal C-C Bond Breaking HDS (sulfides) HDS (thiophenes) HDN HDO Saturation of aromatics Saturation of olefins Isomerization Significant C-C Bond Breaking Hydrocracking of paraffins Opening naphthene rings (3) Dealkylation of aromatics Other Reactions Thermal coke formation Mercaptan formation Examples R-S-R’ + 2 H2 RH + R’H + H2S R=S-R’ + x H2 R-R’ + H2S R=N-R’ + x H2 R-R’ + NH3 R-O-R’ + 2 H2 RH + R’H H2O C7H8 + 3 H2 C7H14 R=R’ + H2 R-R’ n-R i-R R-R’ + H2 RH + R’H -R + H2 -CH3 + RH Cyclo-C7H12 + H2 iso-C7H14 -C3H7 + H2 -H + C3H8 -CH3 + H2 -H + CH4 coke + CH4 + x H2 R=R’ + H2S R-R’-SH HR
© 2014 Paul R Robinson3
Catalyst Wetting Temperature Waves 催化剂润湿温波
© 2014 Paul R Robinson4
Controlling Wetting Exotherms 控制润湿放热

Normal control 正常控制 – Feedback 反馈控制 – Bed outlet T causes controller to change the Bed Inlet T 床层 出口温度升高，控制器会改变床层入口温度 – It takes 3 to 5 min for a change to reach the Bed Outlet

© 2014 Paul R Robinson5
Catalyst Wetting Temperature Waves 催化剂润湿温波
© 2014 Paul R Robinson6
Controlling Exotherms with Quench-Ahead 前馈控制
Illustration of Quench - Ahead



Without cooling between beds, high temperature goes into the
next beds. 如果床层间无冷却，高温会迭加到下一床层
© 2014 Paul R Robinson2
Catalyst Wetting Temperature Waves 催化剂润湿温波
© 2014 Paul R Robinson1
1
Wetting of Catalysts with Oil 催化剂润湿

Wetting is not a chemical reaction 润湿不是化学反应 Heat is released when oil passes through dry catalysts. 当油接触
Bed 1 .OP 5%
.SP 75C
Bed 2 .OP 3%
Bed 2 .OP 5%
Bed 2 .OP 15%
Bed 2 .OP 15%
Bed 2 .OP 10%
Bed 2 .OP 1%
Bed 2 .OP 1%
Bed 2 .OP 1%
.SP 72C
Bed 3 .OP 3%
Bed 3 .OP 5%
Bed 3 .OP 5%
NH3 (ppmv)
© 2014 Paul R Robinson10
3-5分钟后，床层出口温度会显现效果

BUT: Wetting heat waves travel to the next bed in << 1 minute 但是：润湿的温波通过一个床层，一般小于1分钟 Quench-ahead control 前馈控制 Put in quench gas after the bed before the T wave arrives 在温波 到达床层前，打开急冷氢
(1)
–12 to –13 –12 to –18 –15 to –22 –19 to –28 –14 to –16 –30 to –32 (2) -1.6 –9 to –12 –9 to –12 –7 to –11 –5 to –12 –10.1 unknown (2) -18
(1) kcal per mol of H2 consumed or produced (2) No H2 consumed or produced (3) = benzene core
在平衡点附近，小的变化 会有很大影响
Weak Base 弱 碱性 (NH3)
Strong Acid 强酸性 (Cracking Catalyst)
© 2014 Paul R Robinson9
Impact of Ammonia on Cracking Activity 氨对裂化剂活性的影响
Relative Activity
催化剂时，放热

Wetting has caused exotherms of 100˚F (55˚C) per catalyst bed 润湿大约会使每床层温升55C The first oil to hit the catalyst gets hotter and hotter. 油的初次接 触催化剂会放热剧烈 After the heat wave passes, the catalyst is cooled by gas and colder oil. 热流过去后，催化剂会被气体和冷油逐渐冷却