biomass gasification for the production of fuels · biomass gasification for the ... mixed-alcohol...
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University of California, San Diego Los Angeles, August 15th, 2017
Reinhard Seiser
Matthew Summers
Biomass R&D Technical Advisory Committee Meeting
Biomass Gasification for the Production of Fuels
University of California, San Diego Los Angeles, August 15th, 2017
• Biomass contains oxygen (~40 w%).
• Biomass contains a different set of minerals (ash).
• Biomass does not occur in highly concentrated reserves but grows geographically distributed.
• Biomass appears as non-uniform solid, from a wide variety of plants (woody, grassy, stalks, leaves, shells, …)
• Biomass is renewable.
Main Difference between Biomass and Fossil Feedstocks (Crude Oil, Natural Gas, Coal)
University of California, San Diego Los Angeles, August 15th, 2017
Converted to moles: (CH1.43O0.65)n (daf) or ~ (CH2O)n (waf)
daf…dry and ash free waf…wet and ash free
Biomass Composition
0%
10%
20%
30%
40%
50%
60%
Ash w% (dry)
Carbon w% (daf)
Hydrogen w% (daf)
Oxygen w% (daf)
Redwood Mill Residue
Almond Prunings
Almond Shells
Walnut Shells
Corn Stover
Cotton Stalks
Cellulose (C6H10O5)n, 40-50%
Ash: Si, K, Na, Ca, Mg, Al, Fe, and other metals. Inorganics: N, S.
Hemicellulose (~C5H8O4)n, 20-35% Lignin (~C31H34O11)n, 15-35%
University of California, San Diego Los Angeles, August 15th, 2017
Biomass, ~(CH2O)n
Biomass Conversion Vehicle Fuels
Gasoline components
Diesel components
Natural Gas
Isooctane, AKI: 100, C8H18
Toluene, AKI: 114, C7H8
Ethanol, AKI: 99, C2H5OH
Hexadecane, C16H34
Methane, CH4
~CH2 CO2+H2O
~CH2
CO2
CO2+H2O
CH4
CO2
C2H5OH
(No n-Heptane, AKI: 0, C7H16 )
Ethanol, AKI: 99, C2H5OH
Methanol, AKI: 99, CH3OH C+CO2
CH3OH
AKI…Anti-knock index, (RON+MON)/2
(+C+H2O)
Alcohols
University of California, San Diego Los Angeles, August 15th, 2017
• Co-processing feedstock (refinery-, crude-blendstocks) Examples: all types of hydrocarbons outside fuel specifications, hydrotreating of biomass/vegetable oils, biomass/coal.
• Fuel blendstocks (qualify as fuel components but are not widely used fuels themselves) Examples: alcohols, aromatics.
• Drop-in fuels (meet or exceed fuel specifications) Examples: Fischer-Tropsch diesel, renewable natural gas.
• Alternative fuels (outside main distribution networks) Examples: biodiesel, E85, methanol, DME
Definition of Types of Fuels
University of California, San Diego Los Angeles, August 15th, 2017
Lignocellulosic Biomass
Gasification
Hydrotreating Pyrolysis
Hydropyrolysis
Conversion Technologies
H2
Syngas (H2, CO, HC, tars, CO2) Gas Cleanup
H2
Methanation
CO2
Fisher Tropsch
RNG
Diesel
Naphtha
CO2
Methanol/DME
Methanol-to-Gasoline Gasoline (blend stock)
Diesel Naphtha
Hydrotreating H2
Vegetable Oils
Mixed-alcohol Synthesis
Methanol or DME
Ethanol
Neste
CRI (IH2)
Coolplanet
TCG, REII, KIT
Haldor Topsoe (Tigas)
Gobigas
Diesel
Fermentation of CO
Lanzatech
Refinery Gasoline
Kior
Refinery
Gasoline
Gasoline (blendstock) Diesel
Direct Liquefaction
Indirect Liquefaction
Other Feedstocks or Methods
Fulcrum (TRI, tubular FT)
Jet Fuel
Middle distillate Hydroprocessing
Red Rock (Velocys)
Enerkem
TUV, West Biofuels
Frontline
RNG G4 Insights
University of California, San Diego Los Angeles, August 15th, 2017
Gasification – Gas Cleanup – Fuel Synthesis – Fuel Upgrading
Cons:
Pros:
• High temperature – relatively fast process • Gasification creates a known set of gaseous species • A variety of fuels and chemicals can be produced by fuel synthesis • Low level of contaminants in final products
• Many process steps – less efficient, more costly • Often relies on several catalysts – costs and deactivation • Large size – feedstock availability and product distribution need to match
University of California, San Diego Los Angeles, August 15th, 2017
FICFB Gasifier: Converting Biomass to Producer Gas
• Fast Internally Circulating Fluidized Bed (FICFB)
• Fluidized bed using bed material such as Olivine sand
• Indirectly heated, air-blown, ambient-pressure design.
• Low nitrogen producer-gas, acceptable tar levels.
• Cold-gas efficiency > 70%
Senden, Germany ~16 MWfuel
Burgeis, Italy ~2 MWfuel
Gussing, Austria ~8 MWfuel
Woodland, CA ~1 MWfuel
Research CHP CHP CHP
RNG CHP…Combined Heat and Power, RNG…Renewable Natural Gas
Steam
Gasifier
Regenerator (Combustor)
Woody Biomass
Air
Filter Scrubber
Gas Cleanup Fuel Synthesis
(Char) (Tar)
(Sulfur)
Filter(Ash)
Exhaust
Gothenburg, Sweden ~32 MWfuel
Product Gas
University of California, San Diego Los Angeles, August 15th, 2017
Biomassbin
GasifierCombustor
cyclone
After burner
Flue gas Hot filter
Syn
gas
cool
er
Syngas filter
Syngas blower
Flare
Sediment sink
Bio-Dieselmakeup tank
Bio-diesel/H2OPlate HE
Syngas scrubber
Bio-Diesel circulation pump
Steam generator
Propane
Ste
am
Sup
er-h
eate
r
Flue
gas
coo
ler
Fresh water
Plate HE
Air
Intermediate water loop
Compressed air
Flue gas blower
H2O tank
Char collector
Ash collector
Steam
Blowdown
1
2
3
Gas-sampling locations
Scale
AirPre-heater
3b
1b
FICFB Pilot Plant 1MWfuel, 5 tons/day Uses heat recovery for steam generation
University of California, San Diego Los Angeles, August 15th, 2017
Typical Producer-Gas Composition (after raw-gas cleanup and cool down, e.g. sampling point 3)
Compound Chemical
Formula Volume Fraction
Hydrogen H2 0.38 Carbon Monoxide CO 0.19 Carbon Dioxide CO2 0.22 Methane CH4 0.09 Water H2O 0.07 Oxygen O2 0.002 Nitrogen N2 0.02 Ethylene C2H4 0.02 Ethane C2H6 0.002 Acetylene C2H2 0.002 Propylene C3H6 100 x 10-6 Benzene C6H6 0.003 Toluene C7H8 100 x 10-6 Naphthalene C10H8 0.002 Other Tars 0.001 Ammonia NH3 150 x 10-6 Hydrogen Sulfide H2S 100 x 10-6 Hydrogen Chloride HCl 1 x 10-6 Carbonyl Sulfide COS 3 x 10-6 Thiophene C4H4S 5 x 10-6 Methyl Mercaptan CH3SH 50 x 10-9 Carbon Disulfide CS2 30 x 10-9 Benzothiophene C8H6S 12 x 10-9
Suitable for gas engine, but for most conversion processes to fuels, gas needs to be further cleaned.
Depending on steam (water-gas shift), catalysts, residence time.
Decrease with increasing temperature, catalysts, residence time
Depending on biomass composition
Oxygen-blown or indirectly-heated gasifier for low N2 content. Nitrogen content of fuel matters.
University of California, San Diego Los Angeles, August 15th, 2017
FICFB Gasifier in Comparison to other Gasification Technologies
Cons:
Pros:
• Process works – Güssing plant operated 7000 hours/year for 15 years • High efficiency to producer gas, few waste streams (char, tar, water internally recycled)
• High hydrogen and methane amount in producer gas • No oxygen plant required • Size matches biomass logistics (30-100 MWfuel, ~50 mile radius)
• Many process steps – demands on design, operators, and maintenance Problems with: refractory lining, feed systems, tars in heat exchangers
• Consumables – bed material, biodiesel for scrubbing, Ca/K additives • Not zero-emission – exhaust from char combustor
University of California, San Diego Los Angeles, August 15th, 2017
Fischer-Tropsch Synthesis – Larger Scale
Source: DBFZ report, 2009
University of California, San Diego Los Angeles, August 15th, 2017
Feedstock Barrier: Scale and Logistics
• Biomass is distributed and biomass facilities are small. • Refineries are concentrated and large. Fuel specifications for gasoline and jet fuel are tight. • Possibly combine process streams after they are being concentrated in energy:
Thermo-chemical conversion
Refinery Gasoline, Diesel, Jet fuel
Pretreatment
Biomass
Pretreatment
Thermo-chemical conversion
Pretreatment
Thermo-chemical conversion
Pretreatment such as drying, torrefaction, or pyrolysis
Thermo-chemical conversion such as pyrolysis, or gasification+synthesis
Refining such as hydrocracking, hydrotreating, isomerization, distillation, contaminant removal
Small scale Medium scale Large scale
Distance
University of California, San Diego Los Angeles, August 15th, 2017
Fischer-Tropsch Synthesis – Smaller Scale with Centralized Upgrading
ZnO reactor
230 °C,
20 bar
activated
carbon
absorber
slurry bed reactor
Fischer-Tropsch
synthesis
230 °C,
20 bardistillation
column-I
kerosene-II
heavy
HC
tail gas to
engine
steam
separator-I
110 °C,
20 bar
waxes-I
separator-II
10 °C,
20 bar
light
HC
hydrocracker
390 °C,
60 bar
distillation
column-II
H2
separator-III
10 °C,
60 bar
tail gas to
reformer
diesel-II
diesel-I
waxes-II
H2O+
oxygenates
biomass feed
fluidized-bed
gasifier fluidized-bed
combustor
cyclone
filter
flue
gas
steam
air
engine
Gasification Gas conditioning FT synthesis Product separation Product upgrading
kerosene-I
ash
product gas
exhaust
E-60
steam
steam
reformer
800 °C,
20 bar
SCR, NOX and
CO removal
Power generation
naphtha-I
naphtha-II
flue gas
hot-filter
carbon
absorber
RME
scrubber-I
(tar removal)
40 °C, 1 bar
RME
scrubber-II
(polishing)
5 °C, 1 bar
RME
regeneratoractivated carbon
regenerator
1
2
3
6
7
8
I
II
9
5
4
Description
Lower
heating
value
[MW]
Products from FT synthesis
Naphtha 0.24
Jet fuel 6.9
Diesel 22.9
Waxes (further hydroprocessed) 42.8
Total (including waxes) 72.8
Total (liquids) 30.0
Hydrogen to hydrocracker 14.2
Products from hydrocracking
Naphtha 6.4
Jet fuel 12.8
Diesel 21.4
Total (liquids) 40.7
Tail-gas (not recycled)
Combined products
Naphtha 6.7
Jet fuel 19.7
Diesel 44.3
Total final products 70.7
Products per 100 MW biomass
E.g. 5 x 100 MW gasifiers/FT and 500 MW upgrading/refinery
Note: Naphtha fraction needs to be upgraded in isomerization plant, Jet Fuel fraction is only blend stock Technologies change with size (types of gasifier, types of gas cleanup,…)
University of California, San Diego Los Angeles, August 15th, 2017
Fischer-Tropsch Synthesis from Producer Gas to Drop-in Fuel (Diesel, Jet Fuel, Gasoline)
Cons:
Pros:
• Best drop-in diesel fuel. • Relatively high efficiency. • Clean paraffinic production of chemicals.
• Wide product distribution including naphtha and waxes. • Gasoline and jet fuel fractions need to be upgraded in isomerization unit. • Detailed gas cleanup necessary to protect catalyst. • Large-scale installation needed or co-location with refinery. • High-pressure equipment.
University of California, San Diego Los Angeles, August 15th, 2017
Many thermo-chemical processes employ catalysts and are subject to catalyst deactivation. High demands on gas cleanup.
Technical Barrier: Catalyst Deactivation
Contaminant Methanol Synthesis FT Synthesis
Mixed
Alcohol
Synthesis
Fixed-/
Fluidized-bed
Methanation
Particulate < 0.02 mg/Nm3 n.d.
(soot, dust char, ash)
Tars (condensible) < 0.1 mg/Nm3 < 10ppb
Inhibitory compounds < 1 ppm < 1/1000ppm
(class 2-heteroatoms, BTX)
Sulfur < 1 mg/Nm3 < 10ppb < 300ppm < 10/10ppb
(H2S, COS)
Nitrogen < 0.1 mg/Nm3 < 20ppb
(NH3, HCN)
Alkali < 10 ppb
Halides (primarily HCl) < 0.1 mg/Nm3 < 10 ppb
ppm…parts per million, ppb…parts per billion
University of California, San Diego Los Angeles, August 15th, 2017
Mixed-Alcohol Synthesis
0%
20%
40%
60%
80%
100%
120%
CO Conversion Selectivity to Alcohols among all
Hydrocarbons
Mass Fraction Methanol
Mass Fraction Ethanol
Mass Fraction Higher Alcohols
260C, 100bar, GHSV 1000
280C, 100bar, GHSV 1000
290C, 100bar, GHSV 1000
320C, 100bar, GHSV 1000
Bench-scale synthesis reactor at the Woodland Biomass Research Center
• MoS2 based Catalyst from Albemarle. Similar to “Dow” Catalyst, NREL, Range Fuels.
• Allows for 100ppm of H2S in the feed gas. • No further producer-gas cleaning necessary. • Pressures around 100bar are tested. • Methanol and tail-gas recycling is investigated. • Commercially, alcohols and water would be separated by distillation.
• Benchscale, laboratory-scale, and pilot-scale unit. • Collaboration between UCSD, bioenergy2020+ (Austria), and West Biofuels.
University of California, San Diego Los Angeles, August 15th, 2017
Collaboration with bioenergy2020+ and Albemarle • Bench-scale reactor in Woodland, CA (UCSD). Testing of process conditions (5slpm feed gas, 8ml/hr alcohols in single pass)
• Laboratory-scale reactor in Güssing. Long-term testing of catalyst (50slpm feed gas)
• Pilot-scale reactor in Woodland, CA (West Biofuels). Testing of thermal management (250slpm feed gas)
University of California, San Diego Los Angeles, August 15th, 2017
Mixed-Alcohol Synthesis from Producer Gas to Fuel Blendstock (Gasoline)
Cons:
Pros:
• Sulfur tolerant catalyst, virtually no gas-cleanup needed. • Gasoline blendstock with minimal fuel upgrading. • Allows for slightly smaller and decentralized plants near biomass source and fuel terminals.
• Low conversion efficiency (multi-pass gas recycle necessary). • High-pressure, H2S requiring more expensive equipment. • Mercaptan removal from liquid necessary.
University of California, San Diego Los Angeles, August 15th, 2017
Financial Barrier: Scale-up Risk
Cum
ulat
ive
Pro
fits/
Loss
Plant Size
Pre-commercial Demonstration
Scale
Miscalculation of Valley-of-Death can turn a near-profitable projection into the worst-case scenario.
Pilot Scale Laboratory Scale
Commercial Scale
Too large scale-up
Better to scale up in smaller steps
$1M
Range Fuels: 5 tons/day → 125 tons/day (Phase1) … failed Kior: 50 times from demonstration to commercial … on hold
$10M $100M $1B Capital Cost Annual Fuel Production
1 gal 100s of gal 1 million gal >100 million gal
University of California, San Diego Los Angeles, August 15th, 2017
Research Center Topics Guessing, Austria
• Commercial FICFB gasifier • Electricity production in lean-burn SI-engine • District heating • Tar reforming technologies (2x) • Fischer-Tropsch synthesis (2x) • Mixed-Alcohol synthesis • Hydrogen production • Renewable natural gas production (3x)
Woodland, CA
• Fluidized-bed gasifiers (2x) • Fixed-bed gasifiers (2x) • Electricity production in SI-engine with aftertreatment (2x)
• Tar reforming • Mixed-Alcohol synthesis (2x • Renewable natural gas production • Sulfur adsorbent testing
University of California, San Diego Los Angeles, August 15th, 2017
Fluidized-bed Methanation at Various Scales
160 kWSNG
1-6 slpm
5-20 slpm
Our research unit
University of California, San Diego Los Angeles, August 15th, 2017
Commercial Plant for Renewable Natural Gas 100MWbiomass input, 58% efficiency to RNG
Vol%
Methane 86.5%
Ethane 2.8%
Hydrogen 6.4%
Nitrogen 3.2%
Carbon Dioxide 0.7%
Carbon Monixide 0.2%
Moisture 0.1%
Composition without H2 removal
• Pipeline specifications (e.g. Rule 21) call for low hydrogen content (pipeline integrity), but hydrogen allowance may increase over time.
University of California, San Diego Los Angeles, August 15th, 2017
Methanation of Producer Gas to Renewable Natural Gas
Cons:
Pros:
• High-conversion with Ni-based catalyst (99.6%) • High energy efficiency of overall process (60%) • Methane and ethylene (conversion to ethane) in the producer gas are utilized • Pipeline specifications can be met • Minimal fuel upgrading needed
• High demands on gas cleanup (sulfur compounds) • Natural gas prices relatively low • Expensive interconnection (pipeline injection)
University of California, San Diego Los Angeles, August 15th, 2017
Intermediate Step for Scaling up Fluidized-bed Methanation Technology
• Instead of removing CO2 biogas, convert it to more methane. • Uses hydrogen from electrolysis during times when electricity is cheap • Increases biomethane output by ~60% for better economy of scale • Smaller plant size than methanation of producer gas
Source: PSI, 2017
Conventional Biogas Purification
Biomethane
Biomethane
CO2 removal
Methanation H2
electrolysis
Biogas
Biogas
University of California, San Diego Los Angeles, August 15th, 2017
Hydrogen Production from Biomass for use in Fuel Upgrading
• Makes direct use of hydrogen in producer gas • High overall efficiency • Replaces fossil natural gas otherwise used in steam reforming
Source: Loipersböck, 2017
University of California, San Diego Los Angeles, August 15th, 2017
Acknowledgments