Low Temperature CO2 Desulphurisation over Copper …. GNFC case study.pdfLow Temperature CO2 Desulphurisation over Copper promoted catalyst -ActiSorbG1M At GNFC Presented By : S J

Low Temperature CO2 Desulphurisation

over Copper

promoted catalyst - ActiSorb G1MAt GNFC

Presented By : S J DarjeeAdditional General Manager (Operation)

Ammonia-Urea Complex commissioned in 1981

Nitrophosphate Complex:

Ammonium Nitro Phosphate (ANP), Calcium Ammonium

Nitrate (CAN), WNA, AN MELT & CNA Plants.

CHEMICALS:

Formic acid, Acetic acid, Methanol, Ethyl Acetate, Aniline,

Toluene Di-Isocyanate(TDI)

GNFC AT A GLANCE

FERTILIZERS : (MTPA)

Urea : 6,36,000

Ammonia : 4,45,500

ANP(20:20:0) : 1,56,750

CAN (25%) : 1,56,750

WNA : 3,46,500

GNFC AT A GLANCE -PRODUCTS

CHEMICALS : (MTPA)

Methanol : 2,67,300

Acetic Acid : 100,000

Formic Acid : 10,000

Ethyl acetate : 50,000

CNA : 1,15,500

Aniline : 35,000

TDI : 14,000 + 50,000

GNFC AT A GLANCE -PRODUCTS

At GNFC, we have adopted following Guide-words to achieve

value addition :

• Optimal use of manpower resource

• Technical innovations

• Use of wastes to their best ends

•Creating cost – consciousness

• Percolating information to the working hands

• Suggestion scheme

Guide-words

• Set up new plant / revamp existing plant

• Look for technological developments

• In touch with process licensors

• In-house studies

Growth of GNFC

We have three methanol plants

• Methanol-1 plant designed for 60 mtpd and revamped

to 180 mtpd, Commissioned in 1985.

• Methanol-2 plant designed for 300 mtpd and revamped

to 530 mtpd, commissioned in1990.

• Methanol synthesis unit (MSU) for Crude methanol with

90 mtpd methanol in Crude, commissioned in 2006.

Methanol plants

• Methanol is made by following chemical reactions:-

CO2 + 3H2 CH3OH + H2O

CO + 2H2 CH3OH

•At Methanol-2 plant, majority of synthesis gas used for Methanol

reaction is produced through Reforming of natural gas.

• CO2 addition is required for Stochiometry balance to effectively

utilize Hydrogen produced by reforming reaction.

• CO2 is sourced from GNFC Ammonia plant which operates based on

partial oxidation of Fuel oil.

CO2 Desulphuriser at Methanol-2 plant

STEAM

METHANOL-II PLANT

N.G.

HYDROGEN

H2 TO ANILINE/TDI

CO2 FROM AMM

570 TPD

N.G. REFORMIG

HEAT RECOVERY

DESULFURI-ZATION

SYNGAS COMPRESSION

METHANOL SYNTHESIS

CRUDE METHANOL STORAGE

DISTILLATION

PRODUCT METHANOLPSA

PROCESS: METHANOL IS PREPARED IN FOLLOWING STEPS :

1. DESULFURISATION OF NATURAL GAS

2. PREPARATION OF METHANOL SYNTHESIS GAS BY STEAM REFORMING

3. CO2 ADDITION FOR METHANOL SYN GAS PREPARATION FROM AMMONIA PLANT.

4. COMPRESSION AND METHANOL SYNTHESIS AT 65 BAR PRESSURE & 240 0c

5. METHANOL DISTILLATION FOR THE REMOVAL OF LIGHTER & HEAVY IMPURITIES.

CO2 DesulphuriserDesign press.-

18.5Kg/cm2Design temp.-220 oC

• CO2 received at Methanol-2 has following composition.

CO2 : 97.45 (mol %)H2 : 1.75 (mol %)N2 : 0.10 (mol %)CH4 : 0.35 (mol %) CO : 0.35 (mol %)H2S : 5.0 Mg/Nm3.


• Since sulphur in any form is poisonous to Methanol synthesis

catalyst, it is essential to remove it before its addition to Reformed

gas.

•CO2 Desulphuriser was installed in the plant mainly to remove H2S

from the CO2 received from Ammonia plant

• Operating Condition: 18.5 Kg/Cm^2 & 220 Deg.C

•Design:

• 10.2 M3 C7-2 ZnO catalyst by sud-Chemie

• Flow rate:2600 Nm3/Hr.

•H2S inlet : 5.0 Mg/Nm3

•H2S outlet: <0.1 PPMV.


•Sulphur analysis in spent Synthesis catalystYear Wt % sulphur(Max)1994 0.19 1999 0.602005 0.692011 0.08


• We observed sulphur content in spent catalyst removed from

Methanol synthesis reactor in the year 1994,1996,1999 indicating

poisoning of synthesis catalyst due to sulphur.


• We had facility to only analyse H2S, the result of which were alwayscoming to be <0.1 Mg/Nm3 at the exit of desulphuriser.

• We started communications with major catalyst suppliers to GNFCMethanol-2 plant including M/s Sud-Chemie regarding issue ofpoisoning through CO2 addition.

• Our in-house laboratory and R&D Department were also involved invarious analysis and identification of source of sulphur . We boughtinstruments required to analyse total sulphur, COS and any form ofsulphur such as DMS(Dimethyl sulphide).

• Various analysis were carried out in incoming CO2 stream from

Ammonia plant and at the exit of CO2 Desulphuriser at Methanol-2

plant.

• Thus we were able to establish the presence of “ total sulphur”, “COS”

& “Dimethyl sulphide(DMS)” in the exit of CO2 Desulphuriser bed even

though H2S was not present.



Cat. charge

No.

Period Combination of catalyst

Volume of each catalyst in M3

1 11.01.1991 31.01.1992 UCI C7-2 Zno 10.2

2 01.02.1992 09.04.1995UCI C7-2 ZnO 8.7

ICI-51-2 CuO 1.5

3 18.04.1995 29.03.1999UCI C7-2 ZnO 8.7ICI-51-2 CuO 1.5

4 06.05.2000 02.04.2006ICI-51-8 2.0

Puraspec-2312 0.2Puraspec-2020 8.0

•We tried various combination of catalyst as under:


Cat. charge

No.



5 14.04.2006 09.04.2007UCI C7-2 ZnO 0.8

Actisorb G1 ZnO 8.01.4ICI-51-8 PPT

6 27.04.2007 09.05.2008

ICI-51-8 PPT 1.5Puraspec 2010 4.0

Actisorb G1 ZnO 3.3ICI-51-8 PPT 1.4

7 05.06.2009 22.02.2010

ICI-51-8 PPT 1.5Puraspec 2010 4.0Puraspec 2312 1.5Puraspec 2010 3.2

8 05.06.2009 20.02.2010

Puraspec 2030 0.14Puraspec 2010 3.658Puraspec 2312 1.5Puraspec 2010 3.2


Cat. charge

No.



9 23.02.2010 04.06.2010

ICI-51-8 PPT 0.845Puraspec 2030 3.658Puraspec 2010 7.6Puraspec 2312 1.5

10 09.06.2010 17.04.2015Actisorb G1-M 2.04

C-7-6 ZnO 4.08Actisorb G1-M 4.08

11 04.05.2015 Conti.

Actisorb G1-M 1.72

C-7-6 ZnO 4.08

4.0Actisorb G1-M


•We got the real break through in 2010 when Sud-chemie make followingcombination of catalyst in which exceptional catalyst G1-M which wasspecifically offered by Sud-chemie for our service worked very well.

•Following combination of catalyst was charged in 2010 which worked from 09-06-2010 to 17-04-2015

Actisorb G1-M Top : 2.04 M3 C-7-6 ZnO Middle : 4.08 M3Actisorb G1-M Bottom : 4.08M3


•The design flow for this combination was not the 2600 Nm3/hr original design, but it was 5200 Nm3/hr required for our Revamp capacity.

• On broad basis catalyst compositions are as under:-•Actisorb G1M•Physical Properties Chemical composition-wt%•Size : 6X3 mm ZnO : 60 % Min•Shape : Domed tablets Metal oxide: 20%•Bulk density : 1.45+/- 0.1Kg/Ltr. Loss on Ignition at 380°C:6.0%•Crushing strength :>=100N


• On broad basis catalyst compositions are as under:-

•Actisorb S2(C-7-6)•Physical Properties Chemical composition-wt%•Size : 4.7 mm dia ZnO : 90.0 +/- 3.0•Shape : Extrusion Loss on ignition at 540°C: 5.0 %•Bulk density : 1.3 +/- 0.1Kg/Ltr. (Min.)•Crushing strength : 6.8 Kg-DWL (Min.)


• The present 2nd charge of same

combination of catalyst is working since

April-2015 without any trouble.


• CONCLUSION:

• Sud-Chemie make Actisorb G1-M catalyst gave us the

long lasting solution of preventing poisoning of costly

Methanol synthesis catalyst by effectively removing

sulphur content in CO2 stream.


Documents

Low Temperature CO2 Desulphurisation over Copper …. GNFC case study.pdfLow Temperature CO2 Desulphurisation over Copper promoted catalyst -ActiSorbG1M At GNFC Presented By : S J