Needs for upgrading of pyrolysis

oil for refining to conventional

transportation fuels PNNL-ACT-SA-10243

ALAN ZACHER

1

Pacific Northwest National Laboratory International Advanced Biofuels Conference 19 May 2017, Gothenburg, Sweden

Outline

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Spectrum of Needs

What is pyrolysis?

Bio-oil context as an energy carrier

Characteristics of bio-oil

Common upgrading approaches

Upgraded pyrolysis oils in the context of fuel standards

Considerations for liquid transportation

fuels from biomass pyrolysis

May 30, 2017 3

There exist many drivers and needs for biomass derived transportation

fuels

Societal desire for renewables

Regulatory and environmental questions

Stakeholder expectations

Raw material supply and location

Compatibility with existing transportation fuel use

Fuel product specifications

This talk will focus on bio-oil compatibility and specifications

What is Pyrolysis? Direct Thermochemical Liquefaction (DTL)

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Bio-oils: An energy carrier for end-

use or as an intermediate

Quality of bio-oil must be defined in

context of an end-use

DTL variations

Fast Pyrolysis (FP)

Hydrothermal Liquefaction (HTL)

Catalytic Pyrolysis (CFP)

Hydropyrolysis (HFP)

Solvo-thermal Liquefaction (SvTL)

Catalytic SvTL (CSvTL)

DTL: Thermochemical depolymerization of

biomass in low oxygen environment to

produce liquid bio-oil (pyrolysis) or bio-crudes

Processes vary by equipment configuration,

reaction media, reaction temperature (T),

residence time (RT), heating/cooling rates

(ΔRT), to determine product quality and

yield

Bio-oil context as an energy carrier

Pyrolysis oil has a “compatibility barrier” with hydrocarbons fuels

Research in the spectrum of “raw” to “refined” bio-oils in boiler and

engine applications is ongoing

Upgrading requirements depend on application 5

Comparison of wood-derived bio-oil, an

example crude, and resid marine fuel

Characteristic FP Bio-oil Crude oil M. Resid Fuels* (ISO-F-RM_)

Water, wt% 15-25 0.1 <0.3 – 0.5

Insol.solids, % 0.5-0.8 - <0.1

Sulfur, % <0.05 <4 By statute

Ash 0.2-0.3 0.1 0.04-0.15

HHV, MJ/kg 17 44 40

Density, g/ml 1.23 0.86 0.99-1.01

Viscosity, mm2/s 30-85@40°C 3-100@50°C 10-700@50°C

Acid number, mg/KOH/g

80-120 <1 <2.5

Undesired attributes include: Oxygen content, water content, energy density, solids, instability, miscibility, pH, combustion

Desirable attributes include: Low sulfur

Bio-oil is typically upgraded to address these characteristics in the end-use context * Vermeire, M. B. (2007). Everything you need to know

about marine fuels, Chevron Global Marine Products.

Oxygen containing species in bio-oil

Oxygen content in biomass is responsible for most of the differences

between bio-oils and petroleum

Biomass is also relatively hydrogen deficient

Upgrading of bio-oils for transportation fuels should address both

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van Krevelen chart courtesy M. Olarte, TCBiomass 2015

Common Upgrading Approaches

Solvation: Diluents to improve characteristics or suppress chemical

reactions

Physical modifications: Separations, chemical treatment

Catalytic Upgrading: Catalytic hydrogenation

Mild: Partial treatment to improve characteristics or reduce reactivity

Severe: Hydrodeoxygenation resulting in a hydrocarbon.

Production modifications: DTL variations including CFP, HFP, SvTL,

CSvTL

End use modification: Changes to end-use engines, storage,

handling

All approaches add cost

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Impact of Upgrading Approaches

Catalytic upgrading addresses most challenges, but at a cost

Simpler approaches should be considered for less refined fuel

applications

Challenges often interfere with approaches used to address them

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Upgrading approach vs. effect

on addressing negative qualities W

ate

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En

erg

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Den

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Part

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Vis

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Th

erm

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Lo

w p

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Solvation Low None None High High High V. Low High

Physical Mod. High Low High Low Low None None None

Catal Mild High High None Worse High High None High

Severe High High None High High High M / H High

Production mod. Low Low High Low varies Low Low Low

Mod. of end-use ? None None ? None Low Med Med

Summarized from Prospects of pyrolysis of lignocellulosic biomass to produce marine biofuels, ExCo78 workshop, Rotorua, NZ, 2016.

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Thermal instability significantly

interferes with catalytic upgrading

Levoglucosan

Glucose H+

H+

Humin

Carbonyl Species

Sugar Species

Phenolics

Carboxylic Acids

phenol-aldehyde resin

As efficient catalysts for condensation reactions

Bio-oil Thermochemical Polymerization Catalytic Hydrogenation

>80 oC

Sorbitol and C2-C4 diols

Ketone and Aldehydes to Alcohols

Ring Saturation to Alcohols

Hydrogenation to Alcohols

120-180 oC

H Wang et al. ACS Sustainable Chem. Eng., 2016, 4, 5533

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Sulfur interferes with hydrogenation

stabilization of bio-oils

The sulfur-stability cycle can be broken

with:

Catalyst/method to stabilize bio-oil

without low T hydrogenation and/or

Sulfur tolerant catalyst and/or

Method for removing sulfur for bio-oil

Example Approach: Deep Stabilization,

Upgrading

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Long term deactivation

mitigated by deep stabilization

Deep stabilization

140°C, 1800 psig

LHSV = 0.23/h

Upgrading

400°C, 1800 psig

LHSV = 0.17/h

Allows for longer lifetime

hydrotreating

Future research needs are:

Reduced dependence on catalyst regeneration

Limited use of precious metal catalysts

Efficient utilization of hydrogen

Evaluation of product in context of fuel standards

Fuel Product Specifications

Transportation fuels are defined by standards, examples such as:

ASTM D4814, Gasoline

ASTM D975, Diesel Fuel

ASTM D1655, Aviation turbine fuel

Standards functional and empirical analyses are based on petroleum,

and may yield different information when applied to biomass fuel

Some standards (Diesel D975) may not be met even if they are met:

“Some of the properties necessary for use in a compression ignition

engine which are inherent in petroleum derived oils may not be

addressed in Specification D975.”

May 30, 2017 13

Fuel Product Specifications, continued

Some standards (D1655 aviation fuel) cannot be met using biomass:

“shall consist predominantly of refined hydrocarbons…derived from

conventional sources including crude oil, natural gas liquid

condensates, heavy oil, shale oil, and oil sands.”

Creation of new standards may be

necessary, (D7566 synthetic aviation fuel)

Due to internal refinery recycle,

coprocessed biomass molecules could end up

in every product, touching every standard in the refinery

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Suitability testing for upgraded oils

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0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250 300 350 400

16-215-2

16-18-1

7-26-1

7-1

6-2

Simulated distillation ranges T10

-T90

(oC)

De

rive

d R

ON

Fully upgraded wood oils

Upgraded over sulfided catalysts

Fast pyrolysis bio-oil

HTL biocrude

190oC

Ignition Quality Testing of

distilled, upgraded bio-oils

and bio-crudes: Comparison

of derived RON versus

distillation range for various

product distillates

Courtesy Co-optima project, PNNL

Structure of biomass and hydrotreating dictate the hydrocarbon

structure

Predicted RON is low for gasoline, and predicted cetane value

is low for diesel

Demonstrates need for fuel suitability testing and improvements

Summary

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Bio-oils are compositionally different than crude oils, and have

implications to end-use

Upgrading requirements for bio-oils are being researched

Biofuels must be evaluated in the context of current petroleum fuel

standards and analyses

New standards needed soon

Thank You!