needs for upgrading of pyrolysis oil for refining to conventional … · 2017-05-30 · needs for...
TRANSCRIPT
Needs for upgrading of pyrolysis
oil for refining to conventional
transportation fuels PNNL-ACT-SA-10243
ALAN ZACHER
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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
r C
on
ten
t
En
erg
y
Den
sit
y
Part
icu
late
s
Vis
co
sit
y
Th
erm
al
sta
bilit
y
Mis
cib
ilit
y/
ble
nd
ing
Lo
w p
H
Co
mb
usti
on
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.”
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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
May 30, 2017 14
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!