2. Petroleum University of Technology
Gas Engineering Department
Laboratory preparation of modified ZSM- 5 nano catalyst with aluminophosphate (AlPO) for methanol to Dimethyl Ether reaction
By:
yadollah tavan
SupervisorS:
Dr. A. Shariati
Dr. M.R. Khosravi Nikou
October 2011

3. Contents MTD process and their Catalysts Catalyst Characterization
Catalyst Synthesize
Catalyst Characterization
Results
Conclusion

4. Importance of DME
Dimethyl ether (DME) is found to be an alternative diesel fuel because of:
low NO emission
near-zero smoke amounts
less engine noise
and
replace chlorofluorocarbons (CFCs)
used as an aerosol propellant
At present DME is commercially produced by the dehydration of methanol

5. MTD process and its Catalysts
The general reaction path of the methanol conversion:
First methanol dehydration to dimethylether (DME).
Then converted to light olefins.

6. MTD process and its Catalysts
The reaction takes place on:
different solid–acid catalysts such as
γ-alumina
H-ZSM-5
temperature range of 250–400 °С
pressures up to 18 bar

7. Higher Catalytic activity Existence of strong acid-sites
MTP process and its Catalysts
HZSM-5:
Interesting feature:
Drawback
Hydrocarbons formation at 270 C
Higher Catalytic activity
Higher Stability
Higher Performance
Existence of strong acid-sites

8. Catalyst Modification
Generally adopted methods for acidity modification of ZSM-5 are:
Exchange of protons with Na ions
Modification with P containing compounds and Promoters
Using Binder materials
Other modifications

9. Synthesize
Chemicals
Aluminium nitrate nano-hydrate [ANN; Al (NO3)3.9H2 O, extra pure, Merck]
Ortho-phosphoric acid [H3PO4, 85wt%, analysis grade, Merck]
HZSM-5(SiO2 /Al2O3=67.6, ZEOCHEM, Switzerland)

10. Catalyst Preparation Steps
Synthesize
Catalyst Preparation Steps
ANN Dilution
Homogenization
Phosphoric Acid addition
HZSM-5 Addition
Filtration and Washing
Drying

11. Catalyst characterization
XRD
BET
NH3-TPD

12. Experimental Vertical fixed bed micro-reactor
316 stainless steel tubing
I.D = 0.75 inch
length=19 cm
Nearby atmospheric pressure.
Methanol (Grade AA, 99.9% purity, Fanavaran petrochemical) was supplied by the HPLC pump, vaporized through the heater and fed to the reactor.
The reaction temperature from 155 to 460°C.
All the experiments were performed with 3gr of catalysts.
Weight Hourly Space Velocity (WHSV) of 15 to 90 grams of methanol per grams of catalyst per hour (g g-1h-1) by changing methanol rate
Product analysis was performed using gas chromatography (Young Lin, ACME 6100).

13. Results

14. Results Scherrer Equation:
HZSM-5:
B= (1.25°*π/180)
maximum peak was occurred in °
the crystal size derived by Scherrer equation is nm
Synthesized Catalysts:
crystal sizes were 13-15nm for synthesized catalysts and are well nano sized.

15. Specific surface area (m2/gr)
Results
Catalyst
Specific surface area (m2/gr)
HZSM-5
401.52
ZALPO(P/Al=0.3) , A
401.02
ZALPO(P/Al=0.8), B
398.80
ZALPO(P/Al=1.2), C
387.90
ZALPO(P/Al=1.5), D
382.50
The HZSM-5 exhibits higher surface area.
By addition of phosphorus to the binder, the surface area decreased
Attributed to the formation of AlPO

16. Results The nature of N2 adsorption-desorption isotherms
Type IV curve using IUPAC classification for hysteresis loops
The predominance of mesopores for HZSM-5
Mesopores: pore diameter=2-50nm due to capillary condensation taking place in mesopores.
Hysteresis loops may exhibit a wide variety of shapes.
In present work pore shape might be ink-bottle form.

17. Results Pore diameter was varied from 18 to 963nm for HZSM-5.
the prominent distribution was observed at range of 25-47nm mainly includes mesopore size.
Well-developed mesopore structure of the catalyst would help mass and heat transfer easy in reaction.

18. Quantity at low temperature Quantity at high temperature
Results
Catalyst, Sample name
Low temperature
(C)
Quantity at low temperature
(mmol/gr NH3)
High temperature
Quantity at high temperature
(mmol/gr NH3)
Total quantity
HZSM-5
196
0.673
398
0.492
1.165
ZAlPO(P/Al=0.3), A
184
0.519
397
0.413
0.932
ZAlPO(P/Al=0.8), B
0.523
393
0.473
0.996
ZAlPO(P/Al=1.2), C
179
364
0.27
0.743
ZAlPO(P/Al=1.5), D
176
0.453
360
0.263
0.716

19. Results The ammonia TPD plots of the calcined samplesB C D
The ammonia TPD plots of the calcined samples
low temperature peak around 190°C
high temperature peak around 390°C.
The former from the weakly acidic that cover the external surface of the catalysts.
The latter peak arises from the Bronsted acid sites
The intensity of high temperature peak decreases with the increase of phosphorous
Effective interaction of phosphorous with the binder and zeolite framework.

20. Results
The effect of Temperature on HZSM-5:

21. Results The effect of WHSV:
The influence of WHSV within wide range of gr/ (hr.gr-cat) was investigated

22. Results Design of Experiments (DOE): L9 orthogonal array.
Design of Experiments (DOE):
Control Factors
Levels 1 2 3
Temperature(C)
212
230
252
WHSV 15 30 60
L9 orthogonal array
Optimum Temperature was 252 C

23. Results

24. Conclusion In the present research:
Synthesized catalysts showed better conversion than HZSM-5.
It was found that P/Al molar ratio of 0.8 has better conversion than other.
For optimum catalyst, reactor temperature was raised to 315°C and no comparable by-product was detected in GC spectra.

25. Acknowledgments:
I would like to thank Dr. Ahmad Shariati and Dr. Mohammad Reza Khosravi Nikou, for their supervision throughout my research project.
I would like to thank ZEOCHEM,AG company for supplying zeolites.
I would like to thank Abadan Refinery Company and Iranian nanotechnology initiative council for their financial support of my thesis.
Finally, I would like to thank lab mates.

26. Thanks for Your Attention