Conversion of Blended Primary and Secondary Sewage Sludge into Biofuels by Hydrothermal Liquefaction and Catalytic Hydrotreatment ANDREW SCHMIDT, JUSTIN BILLING, KARL ALBRECHT, SAMUEL FOX, TODD HART, GARY MAUPIN, LESLEY SNOWDEN-SWAN, RICHARD HALLEN Pacific Northwest National Laboratory

tcbiomass2017, Chicago, IL, September 21, 2017

1 PNNL-SA-129182

HTL Program at PNNL

2

Develop, demonstrate, and assess HTL technology for sustainable biofuels production.

• Team with other national labs, universities, commercial and industrial organizations

• Obtain currently available feedstocks • Conduct experimental evaluation in continuous, bench-scale systems • Generate data packages and conduct techno-economic assessments

Hydrothermal Liquefaction (HTL) Conversion of a biomass slurry (e.g., wet waste, wood, sludge) to biocrude and aqueous product

300–350°C 2800–3000 psig 10–30 min res. time

Slurry Feedstock

Biocrude Product

Aqueous Product (contains organics)

+ Hydrotreated

Biocrude

Overview: Why HTL?

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Robust and can be applied to wide range of feedstocks at the same processing conditions Conceptually simple (feed preparation, pump, heated pipe, gravity separable biocrude) Wet feedstocks (ag resid, sludge, manure) exploit HTL attributes and minimize deployment challenges associated with pumping HTL biocrude is thermally stable and can be readily upgraded High carbon efficiency to product; greater than 50% to HC product

transportation fuels biocrude waste sludge

HTL Upgrade

Timeline for HTL Development

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DOE Consortia • 2011-2014

NABC - Wood • 2010-2013

NAABB - Algae

2015 Wet Wastes • Grape Pomace,

Spent Grain • Oleaginous Yeast +

Lignin • WWTP Sludge

2015-2016 WE&RF WWTP Project • Demonstration • Report/Validation • TEA and LCA • Recommendations

and Goal Case

2016 Implemented Recommendations • Detroit WWTP Sludge • 20 wt% solids • LHSV = 4 h-1

• Met TEA yield goal of 45%

12 of 14 recommendations were addressed or implemented. The other two applied to CHG.

$3/gge

Base Current

TEA: MFSP

Assessment-driven research and development

Blended Sludge from GLWA/Detroit 50/50 Primary/Secondary

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As Received, 32 wt% Solids, Autoclaved

Immersion Mill (Hockmeyer)

As-processed sludge 20.3 wt% solids. Solids concentration constrained by available sludge and minimum mill batch size.

GLWA Sludge Compared With Sludges from Metro Vancouver (As-Prepared Basis)

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Metro Vancouver primary sludge was diluted to a conservative consistency to ensure pumpability in a first-of-a-kind test (WE&RF) Recommendation following WE&RF tests was to increase the ash-free dry solids content in the feed to increase biocrude yield GLWA blended sludge has higher ash content than MV sludges

GLWA Detroit Metro Vancouver

unit 1:1 Prim:Sec Primary Secondary Total Solids in Feed wt% 20.3% 11.9% 9.7%

FAMES in Dry Feed wt% 6.2% 9.8% 4.7%

Ash in Dry Feed wt% 26.1% 7.5% 16.2%

Ash in Slurry Feed wt% 5.3% 0.9% 1.6%

AF Solids in Slurry wt% 15.0% 11.0% 8.1%

Feed density g/ml @20C 1.065 1.035 0.998

Feed Rate, dry basis g (AFDB)/h 322 - 641 169 122

Separations and Product Images GLWA/Detroit Test

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Well demarcated oil/water separation

Mass of biocrude generated about the same as ash in blowdowns

Test Parameters and Summary Results

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Unit GLWA/Detroit Metro Vancouver

Prim:Sec 1:1 Prim:Sec 1:1 Primary Secondary Ash-Free Solid (Feed) Wt% 15.0% 15.0% 11.0% 8.1% LHSV L/L/h 1.8 3.6 2.1 2.1 Biocrude Gen rate g/h 145 285 64 24 Mass Balance and Yields (Dry, Ash Free, Normalized) Mass Balance % 101% 100% 101% 103% Oil Yield, Mass (N) goil/gfd 45% 44% 37% 25% C Yield, Mass (N) goil/gfd 56% 58% 59% 39% Aqueous Phase COD mgO/L 57,500 61,300 40,800 73,000 Nitrogen wt% 0.74% 0.77% 0.26% 0.72% Phosphate ppm ND* ND* 25 710 Sulfate ppm 140 200 60 160 pH pH unit 7.7 7.8 6.4 8.0

For GLWA/Detroit higher solids concentration and PFR configuration improved operations and biocrude yield/production

* Detroit adds iron for phosphate removal

Normalized Mass Yields

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Mass Yield to Biocrude for GLWA was 44% vs. 37% Yield from Primary from Metro Vancouver

Ash Free Basis

Biocrude Composition Comparison

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GLWA/Detroit Metro Vancouver

unit 1.8 LHSV Prim:Sec 1:1

3.6 LHSV Prim:Sec 1:1

2.1 LHSV Primary

2.1 LHSV Secondary

Carbon wt% 78% 78% 77% 73% Hydrogen wt% 10.6% 10.7% 10.1% 8.7%

H:C, mol ratio ratio 1.61 1.63 1.57 1.43 HHV MJ/kg 39.1 39.6 37.8 34.8

Oxygen wt% 5.3% 4.7% 8.1% 6.5% Nitrogen wt% 5.0% 4.8% 4.3% 5.1%

Sulfur wt% 1.0% 1.2% 0.6% 0.9% TAN mgKOH/goil 52 78 65 38

Density g/ml 0.98 0.98 1.00 0.98 Viscosity cSt@40C 350 355 571 624 Moisture wt% 3.3% 4.4% 13.0% 28.6%

Ash wt% 0.12% 0.06% 0.33% 0.46% Filterable Solids wt% 0.15% 0.12% 0.18% 0.25% Lipid (as FAMES) wt% 19.5% 19.5% NM NM

For GLWA biocrude, H:C ratio, density, and ash values are encouraging. Higher space velocity had little impact on biocrude quality

Hydrotreating of GLWA biocrude

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CoMo/Al2O3 sulfided catalyst at 673 K and 10.6 MPa Run Time: 302 h Biocrude processed: 1700 mL Mass Yield (to HT product): 82%; volume yield: 99% No operational issues; run terminated when feed exhausted

Unit Upgraded Product Biocrude

H:C Ratio Mol ratio 2.0 1.6

O Wt% 1.0% 6.2%

N Wt% <0.05% 4.7%

S ppm 9 11,000

TAN mgKOH/g <0.01 59

Density g/cm3 @ 20°C 0.79 0.98

Viscosity cSt @ 20°C 2.7 400

Simulated Distillation Upgraded GLWA Biocrude

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Boiling Point distribution (ASTM D2887) Comparison GLWA and Tetraselmis (Algae)

Distillate Fraction

BP Range [°C]

Mass Yield [%]

Gasoline 20–150 18%

Diesel 150–390 73%

Residual (Wax) > 390 9%

Future Work

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Sludge Design Case and State of Technology (SOT) Basic engineering R&D: heat exchange and separations Assess biochemical composition versus biocrude yield and quality Testing and development of the Modular HTL System (MHTLS), an engineering-scale test reactor Generate biocrude for Strategies for Co-Processing in Refineries PNNL Scaled HTL System

Skid 1 Feed Prep

Skid 2 HTL

Skid 3 Separation

HYPOWERs team: WWTP sludge HTL demonstration project, led by WE&RF with multiple partners Improve understanding of catalytic upgrading, generate sufficient upgraded product for fractionation and engine testing

Acknowledgements

September 21, 2017 14

U.S. Department of Energy Office of Energy Efficiency and Renewable Energy

Bioenergy Technologies Office

Thank you for your attention.

Karl.albrecht@pnnl.gov Justin.billing@pnnl.gov