acetylene hydrogenation

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Acetylene Selective Hydrogenation

Acetylene Selective Hydrogenation

Công nghệ tổng hợp Hữu cơ hóa dầu

Hanoi 3/2013

Nguyen Duy TrungKSTN HD K54Email: boxfed@gmail.com

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General Introduction

Acetylene Extraction

Acetylene Selective HydrogenationAcetylene 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 IntroductionGeneral 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

SolventEthyleneethane

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 MPa1 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 hydrogenation 2

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

Selective Hydrogenation:CHCH + H2 CH2=CH2 = -176 kJ.mol-1

Non-Selective Hydrogenation: CH2CH2 + H2 CH3-CH3 =-138.5 kJ.mol-1

2CHCH + H2 CH2=CH-CH=CH2 = -172.9 kJ.mol-1

[4]

Oligomerization :nCHCH + CH2=CH-CH=CH2 C2(n+2m)H2(n+3m)

(green oil) Non-hydrogenation reactions:CH2CH2 2C +2H2 = -46 kJ.mol-1 CH2CH2 C + CH4 = -125.6 kJ.mol-1

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Hydro hóa chọn lọc Acetylen toC= 40-100oC P= 15-40 bar Reactor: adiabatic fixed-bed reactor systems. Catalyst:

Sulfide NiCo, Pd-Ag/-Al2O3, Pd/TiO2, Au/TiO2…- Methods: + Raw-gas. + Front-end. + Tail-End.

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

- Catalyst: Pd-Pb/Ag/carrier, NiCo- High Hydrogen Concentration: 10-35% mol => (Coke, green oil)

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 amounts into feed

Position Before light end removal After light end removal

H2/C2H2 ratio Uncontrollable Controllable: 1.2 2.2

Process Control Parameters [5]

Temperature TemperatureHydrogen & 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

ShortRequires 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]

- GHSV= 8000-12000V/V/Hr

- No.of beds in series, with

intercooling:

Feed acetylene contents:

< 5000-6000ppm: two beds

60007500ppm: three beds

7500 10000ppm: four beds

- GHSV= 4000 V/V/Hr

- No.of beds :

Feed acetylene contents:

<5000ppm: one beds

0.51.7%: two beds

1.72.5%: three beds

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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-endFront-end (Pd)Front-end (Ni)Extraction

LOGOSud-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 StabilityCycle 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 steam500oC, 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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References:

[1] Jung H. Kang, Eun W. Shin, Woo J. Kim, Jae D. Park, Sang H. Moon,Selective hydrogenation of acetylene on Pd/SiO2 catalysts promoted with Ti,Nb and Ce, 2000.

[2] Ullmann's Encyclopedia of Industrial Chemistry, page 202 205.

[3] Edgar L.Mohundro, Overview on C2 and C3 Selective Hydrogenation in Ethylene Plants,2003.

[4] M.Rahimpour,O.Dehghani…, A novel configuration for Pd/Ag/Al2O3 catalyst regeneration in the acetylene hydrogenation reator of multi feed cracker, 2012.

[5] Dr. Wolf Spaether, Next Generation of Selective Hydrogenation Catalysts, 2011.[6] A comparison of separation methods for Green Oil inethylene production, Hydrocarbon Asia, Jan/Feb 2007

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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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THANKS FOR LISTENING