PNNL-SA-122060 1

Design, Fabrication, and Testing of the Modular Hydrothermal Liquefaction System (MHTLS) JUSTIN BILLING, DAN ANDERSON, RICH HALLEN, TODD HART, GARY MAUPIN, ANDY SCHMIDT, DOUG ELLIOTT November 3, 2016 TCS 2016 Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products The Friday Center, University of North Carolina-Chapel Hill

Since Last Year…

Water Environment & Reuse Foundation (WE&RF) issued a final report (August 2016) describing the hydrothermal processing of WWTP sludges (first presented at tcbiomass2015)

Available at werf.org Partners include DOE, EPA, municipalities, PNNL, Genifuel, industry consultants

Wet wastes and waste-to-energy has become a primary focus for advanced HTL processing

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https://www.werf.org/i/a/ka/Search/ResearchProfile.aspx?ReportId=LIFT6T14

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Outline

Process History and Overview Scale-up Challenges Identified During Development of Bench Scale Systems Design, Fabrication, and Delivery of the Modular Hydrothermal Liquefaction System (MHTLS) Process Scale-up Factors and Challenges Addressed by the MHTLS

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HTL Timeline (General and at PNNL)

1970s Process Development • Batch and

Model Compounds

1980s Pilot Demon-strations • Albany • Shell HTU • PERC, LBL

2008-2010 Renewed Process Development • Continuous-Flow Process • No Reducing Agent • Agricultural Residues

US DOE Consortia • 2011-2014

NABC • 2010-2013

NAABB

2014-Present Process Scale-up • Genifuel • MHTLS • Steeper • HTU

Go big or go home!

HTL-to-Fuel Overview

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

300–350°C 2800–3000 psig

HTL

Slurry Feedstock

Biocrude Product Aqueous Product

(contains organics)

+

Catalytic Hydrotreatment

Distillation

Fuel Fractions

Hydrotreated Bio oil

Biocrude is upgraded via Catalytic Hydrotreatment and fractionated by Distillation to gasoline, diesel, jet fuel, and bottoms

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Simplified Process Flow Diagram (Bench Scale)

• Conceptually Simple • Feedstock Agnostic • Biocrude Readily Upgraded

Elliott et al. (2015) Bioresource Technology doi:10.1016/j.biortech.2014.09.132

HTL at PNNL – Current Test Stand

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CSTR

Pre-Heater

Main Reactor

Membrane coalescer

Gas BPR

Blow down

Liq. BPR

Badger Valve

Filter

Product Collection

20-liter feed tank

Walk in hood: 7’(L) x 3’(W) x 8’(H)

Current test stands are operated in continuous mode at feed rates of 1 – 4 liters per hour

Commissioned in 2014

Micro GC

Wet Test Meter Wet Test

Meter

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HTL Reactor Design Assessment performed by third party (Harris Group), “Production of Advanced Biofuels via Liquefaction HTL Reactor Design” (April 2013) http://www.nrel.gov/docs/fy14osti/60462.pdf Provides rigor to TEA and expertise on system/reactor design Largest challenges to scale-up:

Heat integration/heat transfer Cost associated with high pressure (scalable reactor design)

HTL Scale-up Considerations Under NABC

Engineering Evaluation of HTL Scale-up

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Feed formatting/pumping At bench scale, with small tubes (~ 1 cm), feedstock formatted to paste consistency, generally conservative to avoid plugging Meaningful pumpability testing must be done at close to plant scale to determine acceptable particle size and slurry maximum concentration

Heat transfer coefficient during slurry heating Need rapid liquefaction to reduce viscosity and increase heat transfer, accurately determine heat transfer coefficient Injection of hot recycle stream – the loop reactor

Hydrothermal Liquefaction Scale-up Challenges

Example: Bench-scale estimation of heat transfer coefficient

Harris Group assigns substantial capital cost to heat exchangers Low heat transfer coefficient with high viscosity feedstock Wall thickness requirement for high pressure (also lowers HTC) For high viscosity feed, HTC estimated at 3–14 BTU/h-ft2-°F

Testing in bench scale system at high feedrates (6 L/h) provided the experimental data to estimate heat transfer rates for FPR slurry Estimate using bench-scale system = 50 BTU/h-ft2-°F, indistinguishable from water in same system

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Heating Profile: Water & Wood are equivalent

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Hydrothermal Liquefaction Scale-up Challenges

Reactor design Continuous stirred tank reactors work well at bench/engineering scale, but need efficient plug flow reactor to minimize capital costs Assumptions on plug flow need to be tested in a pilot system with slurry feed rates on the order of 1 to 4 L/min (i.e., ~ 20 to 60X scale up from the continuous flow system used).

Depressurization Rapid letdown of entire product stream by proportional valve or back-pressure regulator (BPR) BPR for gas phase, liquid via level control

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Hydrothermal Liquefaction Scale-up Challenges

Solids/ash removal PNNL removes solids/ash with filter at HTL temperature and pressure; solids collection done by system blowdown True backflush will improve solids removal and filter pressure drop

Biocrude/aqueous phase separation Continuous phase separation and product collection Pressure and temp of product letdown affects heat integration Improved biocrude recovery from aqueous will have significant impact on process economics

MHTLS: Design to Delivery

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Functional Design Criteria

April 2015

Request for Proposal

April 2015

Award to Zeton

August 2015

Preliminary Hazard

Analysis August 2015

90% Design Review

Complete December

2015

Fabrication December

2015 to May 2016

Factory Acceptance

Testing June to July

2016

Delivery, Installation,

Commissioning August 2016 to

Present

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MHTLS Layout

Skid 1 Feed Preparation

Skid 2 HTL Processing

Skid 3 Separations

12 ft (3.7 m)

Skid footprint is 36 × 16 ft (11.0 x 4.9 m)

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MHTLS Footprint

MHTLS Visuals

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Skid 1 (foreground) and Skid 2 during factory acceptance testing

Primary oil/water separator

MHTLS Visuals

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Hockmeyer HCPS-2.5 Immersion Mill, 15 HP mill, 1.5 HP sweep arm, 32 gal (120 L) batch volume Hockmeyer Equipment Corporation, Harrison, NJ www.hockmeyer.com

Combined trim heater (HE-3) and plug flow tubular reactor (HE-4). Tubing is encased in clamshell aluminum block and heated with electric resistance heaters. Reactor is suspended on rail system for ease of maintenance.

MHTLS Simplified Process Flow Diagram

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Feed Day Tank

Cooler

HP Feed Pump

Blo

wdo

wn

LP Pump

HP Water Pump

Trim Heater H-3

Sep

arat

or

Plug Flow Reactor H-4

Heat exchanger H-1

Badger Valve

Gas Separator

Oil/Water Separator

Vent Gas

Biocrude Aqueous Stream

Filter Solids

Filte

rs

Blow- down

Receipt

Building Water

From Feed Staging Tank

Back Flush Line

To BD-2

At a Glance: Scale-Up Factors

Units Bench-Scale MHTLS Scale-Up

Slurry Flow Rate L/h 1.5–4.0 (2.0)

12–16 (12)

3–10× (6×)

Dry Biomass Feed Rate (15-20 wt%) kg/day 5.7–20.2

(7.6) 45.4–80.6

(45.4) 2–14× (6×)

Biocrude production rate (30-40% yield) kg/day 1.7–8.1

(2.3) 13.6–32.3

(13.6) 2–19× (6×)

Reactor Volume (PFR) L 0.5-1.0 (0.5) 3.0 3–6×

(6×)

Axial Velocity cm/s 1.1–2.9a

(1.4) 4.8-6.4b

(4.8) 2–6× (4×)

Reactor Enclosure Volume (Skid 2) m3 4.76 43.5 9×

Feed prep batch size kg 20-40 120 3–6×

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Nominal values are in parentheses. (a) Assumes ⅜” OD tubing (b) Assumes ½” OD tubing

At a Glance: Process Issues

Bench-Scale MHTLS

Feed Formatting and Pumping

Immersion mill separate from mixing tank, time consuming (8-hr) feed prep; Isco feed pumps

Immersion mill integrated with mixing tank, 1-hr feed prep for 3-6× larger batch; Isco feed pumps

Heat Integration None, all heat exchangers are supplied by hot oil or electric resistance heaters

Cross-flow heat exchanger between feed and product, heat transfer coefficient can be determined

Scalable Reactor Design

Transition from CSTR to hybrid (CSTR +PFR) to tubular plug flow only, axial velocity limited by scale

Higher axial velocities achievable using similar tubing diameters (⅜” and ½” OD) with increased flow rate; small CSTR retained if needed

Depressurization Transition from semi-continuous to continuous product letdown

Continuous product letdown with proportional valve (Badger)

Continuous Solids Removal

Filter/settler vessel with blowdown capability, subject to plugging

Parallel filter-settler vessels with blowdown vessels directly beneath

Product Phase Separation

Historically semi-continuous, moving to continuous product letdown and separation

Dedicated gas-liquid, liquid-liquid separation vessels; aqueous hold vessel and coalescer

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Factory Acceptance Testing and Current Schedule

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Factory Acceptance Testing FAT-1: I/O, cause-and-effect, safety interlocks, calibration FAT-2: prepare and transfer a batch of pine slurry FAT-3: continuous separation of mineral oil and water FAT-4: achieve process conditions (T, P, flow) and heat integration in plug flow configuration FAT-5: achieve process conditions (T, P, flow) in CSTR configuration FAT-6: servicing and maintenance

Delivery, Installation, and Current Schedule

Receipt in two shipments: August 22 and 29, 2016 Installation: reassemble skids, connect to utilities, receive permits, completed installation October 11, 2016 Operational readiness: prepare procedures and receive authorization to start testing (currently underway)

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Acknowledgements

Much of work summarized here and the capital expenditure for the MHTLS was supported by the U.S. Department of Energy's Bioenergy Technologies Office (BETO).

At PNNL, we acknowledge Rolando Lara for his help with contracts and procurement, Tyler Gilmore for his project management support, and Pete Lowry for his timely engagement in hazards analysis. Bill Dey and Emily Wilson provided superb and efficient QA support.

The design expertise and leadership from Zeton, Inc. was outstanding. Special acknowledgement is due to Scott Cooper (project lead), as well as Chris Brown, Chris Hart, Erik Gaspar, and many others.

Back Up Slides

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Pump Assessment Photos of Feedstocks HTL compared to pyrolysis History of HTL (with references)

Identified three types of positive displacement pumps (five vendors) to meet the production rate of 2000 DMTPD (2300 gpm, 15 wt%, 3000 psi), report issued Relevant applications include industrial/municipal sludge, pastes, fibers, silage High confidence in ability to pump immersion milled feedstock; testing required to determine pumpability of larger particle size feedstock Large-scale pumping demonstration required with actual feeds, flow rates, pressures, and temps up to 250°C

Need large quantities of feed and a suitable facility

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Pump Assessment Outcome

Slump Test

REPORT “Review and Assessment of Commercial Vendors/Options for Feeding and Pumping Biomass Slurries for Hydrothermal Liquefaction” http://www.pnnl.gov/main/publications/external/technical_reports/PNNL-21981.pdf

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Pump Options (High Pressure)

Hose-Diaphragm Pumps - Feluwa

Double piston pump

Slump Test

Actual and Potential Feedstocks for HTL

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FOO

D W

OO

D

ALG

AE

SLU

DGE

Pine Paper Fiber

Spent Brewer’s Grains

Grape Pomace

French Fries

Cafeteria Waste

Many Strains

Primary Secondary Digested

As-Prepared

November 3, 2016 27

PNNL-SA-XXXXXX

Liquefaction of Biomass to Biocrude: Fast Pyrolysis and HTL

Conditions Fast pyrolysis Hydrothermal liquefaction feedstock Dry Biomass Wet biomass operating temperature 450-500°C 350°C environment inert gas aqueous condense phase catalyst none alkali reagent operating pressure 1 atm 200 atm residence time < 1 sec 5 to 30 min carbon yield to biocrude 70% 50% oil product quality heating value (HHV, Btu/lb) 6,900 Btu/lb 14,200 Btu/lb

oxygen content 40% <15% water content 25% 5% viscosity@40 °C low (50 cSt) high (4,000 cSt) thermal stability no yes

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HTL Historical Development PERC Process

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HTL Development LBL Process

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HTL Development HTU Pilot Plant

References for PERC, LBL & HTU PERC and LBL Process References

DC Elliott, Chapter 7: Hydrothermal Processing, Thermochemical Processing of Biomass: Conversion into Fuels, Chemicals and Power, Edited by Robert C Brown, 2011, John Wiley & Sons. Rust International Corporation. 1982. Final Report, An Investigation of Liquefaction of Wood at the Biomass Liquefaction Facility Albany, Oregon, Pacific Northwest Laboratory, Contract B-B2471-a-g and Department of Energy Contract DE AC01-78ET 23032, Wheelabrator Cleanfuel Corporation. Released as report PNL-5114, Pacific Northwest Laboratory, Richland, Washington.

HTU References: Berends, R.H., Zeevalkink, J.A., Goudriaan F., and Naber J.E. (2004) Results of the first long duration run of the HTU pilot plant at TNO-MEP, in Biomass for Energy, Industry, and Climate Protection: Proceedings of 2nd World Conference Held in Rome, Italy, 10–14 May 2004 (eds W.P.M. van Swaaij, T. Fj€allstr€om, P. Helm, and A. Grassi), ETA-Florence, Florence, pp. 535–537 (ISBN 3-936338-16-7). Goudriaan, F. and Naber, J.E. (2006) HTU process design and development: innovation involves many disciplines, in Science in Thermal and Chemical Biomass Conversion, (eds A.V. Bridgwater and D.G.B. Boocock) CPL Press, Newbury, pp. 1069–1081. Goudriaan, F, van de Beld, B., Boerefijn, F.R. et al., (2001) Thermal efficiency of the HTU process for biomass liquefaction, in Progress in Thermochemcial Biomass Conversion (ed. A.V. Bridgwater), Blackwell Science, Oxford, pp. 1312–1325.. Goudriaan, F. and DGR Peferoen 1990 Liquid Fuels from Biomass via a Hydrothermal Process. Chemical Engineering Science. Vol 45. No. 9, pp. 2729-2734.

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