1. Municipal Solid Waste to Hydrocarbon Liquids
Mark G. White, Ph. D.
Professor Emeritus and Director Emeritus
Dave C. Swalm School of Chemical Engineering
Mississippi State University, Mississippi State, MS 39762

2. Outline Introduction Enabling Science: Alcohols to Hydrocarbons
Catalyst Design
Experimental—Bench Scale
Results—Bench Scale
Summary

3. Fischer-Tropsch Synthesis
Research Background
Thermal chemical platform for biomass to transportation fuels
Refining/Upgrading
Deoxygenation
Fischer-Tropsch Synthesis
Lignocellulosic
Biomass
Syngas
(CO+H2)
Bio-Oil
Gasification
Fast Pyrolysis
Steam Reforming
Transportation
fuels

4. High Quality Gasoline Production
Anderson-Schulz-Flory (ASF) polymerization kinetics—nonselective formation of paraffins
Co/Al2O3; Fe/Al2O3 ⇒ Paraffins, Wax
⇒ Cracking
Branched/cyclized/isomerized alkanes?
Syngas ⇒ Mixed Alcohols ⇒ Gasoline
⇒ Chemicals
⇒ Distillates

5. Catalyst Design Develop a multi-functional catalyst that:
shows a metal to convert synthesis gas to higher alcohols, and
shows an acid function to convert alcohols to olefins and then olefins to hydrocarbons at high pressures (> 700 psig),
provides for control of molecular weight of products by regulation of pore size.

6. Choice of Metal1
Several metals have been used either alone or in combination with others to make alcohols:
Alkali/Cu/ZnO/Al2O3: MeOH catalyst (200 C)
Alkali/ZnO/Cr2O3: MeOH catalyst (~325 C)
Alkali/CuO/CoO/Al2O3: Modified FTS
Rh/support: Ethanol catalyst
MoOx/C: Higher alcohols catalyst (>325 C)
Dehydration reactions over acid occur at temperatures > 350 C Pamela Spath and David Dayton; “Bioproducts from Syngas”

7. Enabling Science: Alcohols to Hydrocarbons

8. Results from Batch Reactor Studies having Different Initial Pressures
Batch reactor studies with the same amount of catalyst (1 g H+ZSM-5; SiO2/Al2O3 = 23) at 350 C for 2 h using 20 g, initially, of MeOH. Initial pressure of He was varied between 0 and 500 psig.
Very little change in the yield of gasoline at the end of the experiment: g of gasoline.
From these results, we suggest that the MTG catalyst can be operated at 1100 psig without any deleterious effect.
One test was completed in which H2 was used instead of He at an initial pressure of 300 psig. The yield of gasoline was 2.6 g. The gasoline product obtained with H2 was lighter than that obtained when He was present.
Amit C. Gujar, et al. “Reactions of methanol and higher alcohols over H-ZSM-5”, Applied Catalysis, A. General 363 (2009) 115–121.

9. Batch Reactor Studies to Document Effect of Changing Alcohol
Batch reactor: 350 C, 2 h,1 g of H+ZSM-5 (silica/alumina = 23)
He initially = 300 psig, amount of alcohol = 1 mole of C.
For all ROH other than MeOH, tetramethyl benzene was 0%.
Production rates of gasoline higher for higher alcohols; as much as 10 times higher for certain butanol isomers.
The (R+M)/2 octane number is higher for gasoline produced from higher alcohols, as much as 9 points (96 vs 87) Amit C. Gujar, et al. “Reactions of methanol and higher alcohols over H-ZSM-5”, Applied Catalysis, A. General 363 (2009) 115–121.
101 85 87

10. Gasoline Properties from H+ZSM-5
Reactant was i-butanol in a flow reactor operating a 400 C and 500 psig He. Tube diameter was 1”.
Alcohol conversion was total.
(R+M)/2 = 96.
API gravity = 50o; = 60o for a 410 EP-gasoline.
The Reid Vapor pressure = 13.5 psig; RVP for gasoline = 7-10 psig.
The IBP for our product is the same as gasoline and so are the boiling temperatures for the first 20 vol %.
From 20 to 90 vol% our fuel contains a mixture of gasoline with a heavier hydrocarbon.
Our product is a high-value, gasoline bending stock.

11. Catalyst Design

12. Catalyst Design: Why Mo/H+ZSM-5 ?
Mo/H+ZSM-5 is active for methane aromatization in non-oxidative conditions (S. Liu et. al., J. Catal., 181 (1999) )
(CHx → Aromatics)
Mo/H+ZSM-5 is active for alcohols (methanol, ethanol) to olefins and aromatics (F. Solymosi et. al., J. Phys. Chem. B 110 (2006) ; J. Catal., 247 (2007) )
MoCx is active for syngas to mixed alcohols (X. Minglin et. al., Fuel 86 (2007) ; 87 (2008) )
MoCx is active for alkanes isomerization (Marc J. Ledoux at. al, Ind. Eng. Chem. Res., 35 (1996) ; Chem.Tran. Metal Carbides and Nitrides (1996) ; G. Boskovic et. al., Appl. Catal. A: Gen., 317 (2007) )

13. Choices of Acid Function
Zeolites offer strong acidity, high ion exchange capacity, and controlled pore sizes.
Small pore: zeolite A (< 5 Angstroms)
Medium pore: H-ZSM-5 (5.6 Angstroms)
Large pore: Y-faujasite (9.8 Angstroms)
Control support: non-porous silica
Low (no) acidity, no pores

14. Experimental

15. Incipient wetness impregnation
Catalyst Preparation
Incipient wetness impregnation
Mo precursor: (NH4)6Mo7O24·4H2O
Supporting materials:
NH4ZSM-5 (SiO2/Al2O3 = 23, 50, 80, 280), H-Y (SiO2/Al2O3 = 80), H-β (SiO2/Al2O3 = 23), SiO2
Mo loading amount: 5 wt.%, 10 wt.%
Calcination: 773K, 3 hours

16. BTRS-JR Laboratory Reactor SystemAr N2
Pre-heater P
Mass Flow Controllers
Furnace & Temperature Controller
Condenser
Liquid Sampling
Back Pressure Valve
Fixed-bed Reactor
To Online GC O2
CO+H2 H2
Syngas: 47% H2 + 47% CO + 6% N2
Temperature: 523K-653K
Pressure: 500psi, 1000psi
GHSV: 3,000 mL/g-cat/hr
Cat. Charge: 1.0 g
Internal standard method:

17. Bench scale Results

18. The Effect of Pretreatment Conditions
CO conversion over 5%Mo/H+ZSM-5 (SiO2/Al2O3 =50) at 623K and 500 psi.
(□): Catalyst pretreated in methane at 923K
(■): Catalyst pretreated in syngas at 673K
Syngas is the better pretreat gas
Product selectivity over 5%Mo/HZSM-5 (SiO2/Al2O3 =50) at 623K and 500 psi (catalyst pretreated in syngas at 673K).
(■): Total liquid hydrocarbons
(□) : CO2
(△): Lower hydrocarbons (C1-3)
System is stable for 24 h

19. Mo/H+ZSM-5 at Different Temp.
P=1000 psi
Activity (%)
(■) Based on internal standard
For T < 623 K, activity is
stable for t ~ 24 h.
Selectivity (%)
(■) Liquid hydrocarbons + oxygenates
(△) Lower hydrocarbons (C1-C3)
(□) CO2
Higher temperature gives less
liquid and more gas

20. Comparison with Some Literature Data
Catalyst
GHSV (h-1)
Temp.
(K)
Pressure
(psi)
CO Conv.
(%)
Product Selectivity (%)
CO2
C1-3
Total L.
5%Mo/H+ZSM-5
3000
573
1000
15.2
49.6
24.5
25.8
623
500
31.8
51.7
35.2
13.0
K/β-Mo2C
2000 [1]
1160
23.4
~50.0
23.7CHx
26.3Alc
K/Ni/β-Mo2C
73.0
27.5CHx
22.5Alc
Cr2O3-ZnO+H+ZSM-5
340 [2]
673
735
~75.0
15.0
35.0
3100 [2]
440
~25.0
30.0
20.0
5%Mo/H+-Y
13.9
38.6
30.4
31.0
[1] M. Xiang , et. al., Fuel 87 (2008) 599–603
[2] J. Erena, et. al., J. Chem. T echnol. Biotechnol. (1998), 72,

21. Gas Phase Products

22. Liquid Phase Products Oil Phase Water Phase
Total concentration of oxygenates: 2~5 wt.%

23. H+ZSM-5 and SiO2 as the Supports
Distribution of gas phase hydrocarbons on 5%Mo/H+ZSM-5 (SiO2/Al2O3 = 23) and 5%Mo/SiO2 at 573K and 1000 psi

24. TPR Results of Mo/H+ZSM-5
Mo6+ → Mo4+
Polymolybdate MoO3
Crystallite MoO3
TPR profile of fresh Mo/H+ZSM-5 (SiO2/Al2O3 = 23) in 10%H2 + N2.
TPR of MoO3
Step 1 (< 873K): Polymeric octahedral coordinated molybdenum oxo-species
(Mo+6 → Mo+4)
Step 2 (> 873K): Octahedral polymeric molybdenum species (Mo+4 → Mo0)
Tetrahedral monomeric molybdenum species (Mo+6 → Mo0)

25. Effects of Zeolite Acidity and Structure
Catalyst
SiO2/Al2O3
Temp.
(K)
Pressure
(psi)
CO Conversion
(%)
Product Selectivity (%)
CO2
C1-3
Total L.
5%Mo/H+ZSM-5 23
573
1000
10.5
58.6
15.5
2.9
623
500
47.5
54.0
47.1 -- 50
15.2
49.6
24.5
25.8
31.8
51.7
35.2
13.0 80
32.4
62.3
26.7
11.0
51.2
57.6
41.8
0.6
280
20.6
64.2
25.5
10.3
44.6
61.7
36.5
1.8
5%Mo/H+-Y
13.9
38.6
30.4
31.0
5%Mo/H+-β 25
13.5
63.4
40.7
39.1
39.4
Shetian Liu, et al., “Synthesis of Gasoline-Range Hydrocarbons over Mo/H+ZSM-5 Catalysts”,
Applied Catalysis, A: General, 2009, 357,

26. Effects of Zeolite Acidity and Structure
■: Linear Alkanes; ■: Linear Alkenes; ■: Aromatics; ■: Branched & Cyclized Alkanes.

27. Reaction Temperature on Oil Composition
Composition of liquid hydrocarbons from reaction on 5%Mo/H+ZSM-5 (SiO2/Al2O3 = 50) at 1000 psi and different reaction temperatures
Temp.
(K)
CO Conversion
(%)
Effluent
H2/CO
Total Liquid Selectivity (%)
Product Distribution (%, carbon basis)
Aromatics
Branched/Cyclized Alkanes
Linear Alkanes
523
~1.0
1.00 ~
91.8
9.7
0.1
548
3.8
1.01
90.2
573
14.0
1.05
18.4
87.5
12.1
0.4
623
54.0
1.29
14.6
88.7
9.6
1.7
653
64.4
1.32
9.9
97.6
2.1
Reaction on Mo/H+ZSM-5 proceeds inside zeolite channel via mixed alcohol formation as the first step for hydrocarbons formation

28. Reaction Rate Law
Particles
Powder

29. Activation Energy Plot
11 kcal/mol
26 kcal/mol
6 kcal/mol
10 kcal/mol
20 kcal/mol
37 kcal/mol

30. Selectivity to Products

31. Summary
Mo/H+ZSM-5 has been found active in syngas to hydrocarbons reaction.
Aromatics (Tol, p-X) are dominant products on Mo/H+ZSM-5 and branched/cyclized alkanes are dominant products on Mo/Y-faujasite.
Reaction on Mo/H+ZSM-5 proceeds inside zeolite channel via mixed
alcohol formation as the first step for hydrocarbons formation
Decreasing the formation of CO2 and lower hydrocarbons is the
major task in the development of Mo/Zeolite based catalysts.

32. Pilot Scale Results for Single tube Reactor

33. GC/MS Results for Pilot Scale Reactor, Mo/H+ZSM-5 (325 C; 975 psig)
The catalyst was 5%Mo/H+ZSM-5 (SiO2/Al2O3 = 50).
CO conversion was 15%.
The organic liquid phase (red) was examined by a GC/MS along with a sample of 93 Octane gasoline (green).
Part of the organic liquid phase showed components similar to gasoline sample but also contained a significant number of components that were higher molecular weight hydrocarbons.

34. Process Design

35. Preliminary Process Flow Sheet
Low-BTU gas
Synthesis Gas Feed
Membrane Separator
HE 4
High-BTU gas
HE 2
D-2
C-1
HE 1 L
LPG gas
HE 3
A 1 S 1
CO2 + steam
R e a c t o r
F r a c t i o n a t o r R
LPG gas
Unit
Description
HE-1
Heat Exchanger
HE-2
HE-3
HE-4
C-1
Heat Exchanger Gas Compressor
E-1
Expander
D-1
Decanting Drum
A-1
Gas Absorber
S-1
Steam Stripper
D-2
E-1
Light Distillate
steam
D-1
Expansion Valve
Water
Middle Distillate

36. Thank you for your attention!
Acknowledgments
This material is based upon work performed through the Sustainable Energy Research Center at Mississippi State University and is supported by the Department of Energy under Award Number DE-FG3606GO86025.
Thanks to Dr. Amit Gujar (ROH to hydrocarbons); Dr. Shetian Liu (Syngas to hydrocarbons).
Thank you for your attention!