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 white@che.msstate.edu

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

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

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

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.

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. 1Pamela Spath and David Dayton; “Bioproducts from Syngas”

Enabling Science: Alcohols to Hydrocarbons

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: 1-1.8 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.

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

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.

Catalyst Design

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) 175-188) (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) 21816-21825; J. Catal., 247 (2007) 368-378) MoCx is active for syngas to mixed alcohols (X. Minglin et. al., Fuel 86 (2007) 1298-1303; 87 (2008) 599-603) MoCx is active for alkanes isomerization (Marc J. Ledoux at. al, Ind. Eng. Chem. Res., 35 (1996) 672-682; Chem.Tran. Metal Carbides and Nitrides (1996) 373-397; G. Boskovic et. al., Appl. Catal. A: Gen., 317 (2007) 175-182)

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

Experimental

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

BTRS-JR Laboratory Reactor System Ar 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:

Bench scale Results

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

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

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, 190-196

Gas Phase Products

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

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

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)

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, 18-25.

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

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

Reaction Rate Law Particles Powder

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

Selectivity to Products

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.

Pilot Scale Results for Single tube Reactor

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.

Process Design

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

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!