This document provides an overview of acetylene selective hydrogenation processes. It discusses how acetylene is extracted from hydrocarbon streams using solvent absorption or selective hydrogenation. The two main types of selective hydrogenation are front-end, which treats lighter feedstocks before fractionation, and tail-end, which treats C2 fractions after removal of lighter components. Tail-end hydrogenation is more common and uses palladium-based catalysts with high selectivity for acetylene. The document also reviews catalyst regeneration methods used to remove coke and restore activity.

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Acetylene Selective
Hydrogenation
Công nghệ tổng hợp Hữu cơ hóa dầu
Hanoi 3/2013
Nguyen Duy Trung
KSTN HD K54
Email: boxfed@gmail.com

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General Introduction
Acetylene Extraction
Acetylene Selective Hydrogenation
Catalyst regeneration
Contents

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Steam
Cracking
Cracking
Xúc tácOlefin
General Introduction

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Olefin
Alkan Acetylenic
Sour
gas
General Introduction

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Feedstock %Conv Acetylen
(%wt)
Ethane 65% 0.4 - 0.50
LPG 90% 0.65 - 1.35
Naphta - 0.10 - 1.0
[2]
General Introduction

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Tại sao phải loại bỏ acetylen ?
 Xúc tác quá trình polime hóa etylen rất nhạy với sự có mặt
axetylen: ngộ độc, tạo cốc.
 Ảnh hưởng đến quá trình tách các chất, sử dụng dung môi trích
ly (ví dụ: muôi axetat amoni đồng I )
 Không thể tách loại hoàn toàn acetylen bằng phương pháp
chưng cất thông thường.
 Thu hồi etylen.
General Introduction
General Introduction

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Specs Etylen Raw Propylen Clean Propylen
Axetylen, max
(ppm)
2 * 10 5
* <1ppm [3]
General Introduction

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General Introduction
[4]

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Acetylene Extraction1
Acetylene Selective Hydrogenation2
[2]

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Acetylene Extraction1
C2 Fraction Absorber
Solvent
Ethylene
ethane
Solvent +
Acetylene Distillation
Acetylene
Solvent

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- Solvent: DMF (Dimethylformamide)
Linde’s ARU Process (Texas/USA)
- Capacity
+ Feed: 1 057 000 MTA
+ Acetylene: 14 400 MTA- Product: Acetylen 99.9%
DMF <50 ppm http://www.linde-le.com
0.8-3 MPa
1 atm

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- Các nhà sản xuất lớn: Dow Chemical (USA),
Petroment at Varennes in Canada.
- Tổng lượng Acetylene sản xuất: 112000 tấn/năm.
Acetylene Extraction1

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Acetylene Selective Hydrogenation2

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The Selective Hydrogenation:
C3 Selective acetylene hydrogenation2
C2 Selective acetylene hydrogenation1
C2H2 C2H4
CH3-C≡CH
CH2=C=CH2
CH3-CH=CH2
MAPD
Acetylene Selective Hydrogenation2

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Acetylene Selective Hydrogenation2
[4]

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Hydro hóa chọn lọc Acetylen
1948 1980 1995
Xúc tác NiS/Al2O3 (SiO2) Cd, Ca, Ba/ Cr2O3 Pd-based/ Al2O3, SiO2
Acetylene Selective Hydrogenation2

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Raw-gas Acetylene Hydrogenation
Drawing of Sud-Chemie [3]
C2,C3+
H2,CO, H2S
- HC feed: C3+ <<
- Catalysts: Ni-
based (Ni-Co-Cr)
[4]

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Front-end Acetylene Hydrogenation
C2H2, C2H4, C2H6
H2, CO
Remove
CO2,H2S Drawing of Sud-Chemie [3]

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Tail-end Acetylene Hydrogenation
C2H2, C2H4,
C2H6
Removal
CO2,H2S
Drawing of Sud-Chemie [3]

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Hydro hóa chọn lọc AcetylenAcetylene Selective Hydrogenation2
Front-end Tail-end
Feed C2 cut and lighter material.
-Excess hydrogenbecause all
the hydrogen produced in the
cracking furnaces is in the
reactor feed.
C2 cut only
-Hydrogen in the Craked gas
(CG) have been removed
- H2 (99.9%) and CO are
injected in stoichiometric
amountsinto feed
Position Before light end removal After light end removal
H2/C2H2 ratio Uncontrollable
Process Control
Parameters[5]
Temperature Temperature
Hydrogen & CO injection
The selectivity of
hydrogenation reaction
Lower Higher

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Frond-ent Tail-end
Ethylene
loss
Higher Minimize
Catalysts
- Chervon Phillips: E-Series (Pd-
Ag/Al2O3).
-Sud-Chemie:G-83C (Pd-Ag/Al2O3)
- BASF: HO-21 (Pd-Ag/ SiO2)
-Sud- Chemie:G-58C, G-58D,
G-58H (Pd-Ag)
- AXENS: LT-279
Cycle
length
Long
Typically no regeneration [5]
Exsitu regeneration
Short
Requires frequent regeneration
(1-4 times/years)
Insitu regeneration [3]
Catalyst
deactivation
Coke, COS Coke, Green Oil, COS
Acetylene Selective Hydrogenation2

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s Acetylene Selective Hydrogenation2
Frond-ent Tail-end
Design
parameters
[3]

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Method Number of plants % of Plant
Tail-end 174 64
Front-end (Pd) 69 26
Front-end (Ni) 9 3
Extraction 19 7
Total 269 100%
Acetylene Selective Hydrogenation2
[4]
Tail-end
Front-end (Pd)
Front-end (Ni)
Extraction

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Sud-Chemie Tail-End Hydrogenation

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Tail –end Hydrogentation Catalyst
[5]

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Advantages of OleMax 207 new catalyst
Increased:
 Ethylene (>10% OleMax 201)
Catalyts Stability
Cycle lengths (>24 months)
Operation without CO injection
Low Polymer Formation
[5]
OleMax 207 catalyst:
+ Pd-Ag promoter/Al2O3
+ 2-4mm spheres

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[5]

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[3]

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Catalyst regeneration
[4]

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Catalyst regeneration
[4]
Start with warm up by nitrogen injection
to purge residual gases in reactor and
vaporize volatile compounds
Nitrogen and HP

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Catalyst regeneration
High pressure steam
500oC, 500bar
Steam/ Air
 Air : low rates to avoid uncontrollable heating.
 toC < 540oC: avoid catalysts sintering.

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Catalyst regeneration
Cooling stage begins when [CO2] in oulets < 1%V
Cooling to 250oC
by air/steam
N2
H2
N2

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Other references document:
 Robert a Meyers, Handbook of Petroleum Refining Processes Third-
Edition, Chapter 8.2
 U.S Patent No.4404124, No.6,509,292 B1
 T.V.Choudhary,C.Sivadinarayana…,Acetylene hydrogenation on Au-based
catalysts, 2002.
 F.M.McKenna, L.Mantarosie…, Selective hydrogenation of acetylene in
ethylene rich feed streams at high pressure over ligand modified
Pd/TiO2, 2011.

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