Small and highly efficient hydrothermal liquefaction …...Needfor innovation!! •Biomassdo not fit...
Transcript of Small and highly efficient hydrothermal liquefaction …...Needfor innovation!! •Biomassdo not fit...
Small and highly efficient hydrothermal
liquefaction (HTL) units for scalable mass
implementation in biomass conversion
Ib Johannsen, V.Milkevych, D.More, B.S.Kielsgaard, K.Anastasakis, P.Biller
Bio2Oil IVS and Dept. of Engineering, Aarhus University, Aarhus, Denmark
Overview
• Biorefining - the challenge of decentral and complex ressources
• No single solution - Center for Biorefinery Technologies
• Hydrothermal conversion
• Key technology innovations
• Bio2Oil
• New concepts – small modular units
Biorefining requires innovation
• Biomass do not fit into existing
technology platforms:
• Present chemical and refinery
industry is based of fossil fuels
Need for innovation!!
• Biomass do not fit into existing
technology platforms:
• Present chemical and refinery
industry is based on fossil fuels
• Ressources that are big and centralized -Biomass is not!!
• Need for EFFICIENT, decentral solutions
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Pres
sure
(bar
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Temperature (°C)
Lique
fact
ion
(vapour)Carb
onisa
tion
Supercritical Gasification
(liquid)
Critical point
Hydrothermal conversion (liquefaction) (HTL)
• Biomass feedstock is pressure cooked in hot-compressed water
• No dry feedstock required
• Mimics natural fossil fuel creationà coal, oil, gas
§ HTL can convert any biomass to a high energy density bio-crude
§ One of the main advantages of HTL is the high flexibility of
feedstocks and products.
Water-phase diagram
HTL technology at AU pilot
07/06/201916/01/2018
• Continuous pilot scale Hydrothermal liquefaction reactor, capacity up to 100 L/h, residence time ~15 min
• Wet biomass is processed at 350°C and 200 bar to produce bio-crude, solid residue, process water and CO2
• More than 70% of energy content ends up in crude oil fraction (>35% of mass)
• Xenobiotics and microplastics are converted as well
Biomass feed (sewage sludge) HTL 350°C, 200 bar, 15 min Bio-crude (35 MJ/kg)
Time
Position in reactor
Local flowrate
Average flowrate
How to handle the need for long residence time and thus low flow?
on Non-newtonian (tixotropic) biomass,
With low heat transfer properties, fouling/sedimentation issues
140 m of 14mm id tube
Strong non-newtonian viscosity of suspended biomass:
16,0 % DM
16,0 % DM
4,4%
8,3 % DM8,3 % DM
4,4 % DM
∆P η
Flowrate Shearrate∆P
Biomass
Example:
Milled pine in water
Simple flow rheometer
Heat exchange via ‘heat Clamps’
Challenge:Efficient heat tranfer at high pressure
and temperature with no flow
constriction (cleanability)
Solution:
Thermal expansion adapted heat
transfer blocks
Inconel 625 and special cast iron
12, 6 vs 12,7 x 10-6 K-1
Surprisingly efficinet:
24 m counter current dual tube
25,6 mm Od 13.8 mm Id
Delta t 28oC, at 38 l/hr, (280oC)
(Comsol model in accord)
Pilot reactor with oscilation – heat recovery
Heat recovery:
79% without oscillation
84% with oscillation
Important?
Saves more than 20% energy!
07/06/201916/01/2018
Energy analysis – pilotscale
07/06/201916/01/2018
Sludge+ biomass filtration
Flow rate (l/h) 60
DM content feedstock 0.25
Time (h) 1
Feedstock consumed (kg, dry) 15
Energy in feedstock (kW, dry) 82.5
Bio-crude yield (wt.%) 41.8
Energy in bio-crude (kW, dry) 62.8 (HHV= 36.1 MJ/kg)
nth (%) 76.1
Trim heater energy requirement (kW) 5.4
Reactor energy requirement (kW) 2.5
Main pump energy requirement (kW) 0.7
Sludge filtration unit (kW) 0.6
ntot (%) 68.9
EROI 6.8 (towards 10 in full scale)
And Now it’s ready (Almost)
So pilot scale works – what about full scale
Bio2oil’s mission:
1. Produce small standard size scalable units
2. Reduce capex/volumebelow that of large scaleplant
3. Market processes thatare economicallyfeasible withoutsubsidies
?
Bio2oil standard unit
30 x scale-up from Pilot unit in twice the volume
Capacity 4000 ton DM/yr - (feed 3 m3/hr)
Price tag 2M€ - same or lower than large scale plants
Consists of two 40’ containers containing:
1. Novel pumping and depressurization units + separation
2. Multitube heat-exchanger, heater and reactor
Heat recovery 90%, up to 20% drymatter feed, fully automated
IPR on key technologies
Scalablity
• 4000 ton DM/yr
• 15000 ton DM/yr
So pilot scale works – what about full scale
Bio2oil’s mission:
1. Produce small standard size scalable units
2. Reduce capex/volumebelow that of large scaleplant
3. Market processes thatare economicallyfeasible withoutsubsidies
?
80€/ton
How to get a feedstock that warrant a HTL business in Europe
In a no subsidy environment its hard to make a viable HTL business Biomass costs in Europe approaching 80€/tonFeedstock cost >200 €/ton crude oil - no room for processing costs
Negative cost feedstocks seem attractive§ Waste water treatment sludges have negative cost
§ But are often available with low DM content (1-5%)
§ We noticed that our usual HTL feedstocks like wood chips are fibrous after extrusion
§ What if we could use this material for filtration – a filter aid?
§ The filter medium adds organic material for the HTL process to produce additional fuel
Sludge filtration using biomass
§ Filtration times reduced form ~ 20 mins to 1 min
§ Cake resistance reduced by orders of magnitude
§ 1 filter aid unit required per 4 units of dry sludge
§ Batch filtration studies used to calculate scaled up
continuous operation on continuous filter systems.
§ WWTP of 200,000 PE requires 3 tons of waste
biomass per day for all the sludge filtration on a
8m2 drum
07/06/201916/01/2018
Using biomass filter aid
Without biomass filter aid
Bio-crude from sludge
07/06/201923/05/2018
C H N S O
HHV
(MJ/k
g)
Energy
Recovery
(%)
With K2CO3
Sludge 72.8 9.7 2.3 0.8 14.4 36.1 55.5
Miscanthus 74.4 7.1 0.6 0.1 17.9 32.1 48.4
Pine 74.2 7.7 0.3 0.0 17.9 33.0 40.3
No catalyst
Sludge 74.6 10.1 2.5 0.7 12.2 37.7 66.8
Miscanthus 72.9 6.4 0.5 0.1 20.1 30.3 40.2
Pine 71.1 6.9 0.2 0.0 21.8 30.2 50.7
Sludge Co-liquefaction with biomass filter aid with
Miscanthus 74.3 9.3 2.4 0.5 13.6 36.1 80.5
Pine 73.8 9.3 2.2 0.5 14.2 35.9 79.7
Co-liquefaction of biomass filter aid and sewage sludge has synergistic beneficial effects:
Higher bio-crude yields than the separate counter parts
Higher energy recovery
Lower oxygen content
use of alkali catalysts for HTL of lignocellulosics is avoided
✘A part of nitrogen ends up in the bio-crude during co-
liquefaction
Initially we are aiming to make low grade fuel and bitumen
Bio-crude yield
Bio-crude composition
Carbon flow in a modern, fully optimized WWT plant
12% carbon
into fuel - CH4
Integration in WWT – what industry wants
• Solve our sludge problem (digestate)
• Posible but not optimal
solution
• High ash feedstock
Integration in WWT – the simple way
• Fits within normal plant design
• Solves the problem of
pathogens, plastics and drug
residues
• Significant reduction of aeration
costs
Carbon-balance
Phosphor recovery – ongoing research
§ At 350°C and 200 bar phosphates and other high valance salts are insoluble in water
§ Phosphate precipitates and is filtered out continuously
§ Phosphorous recovery in concentrated solid residue is >95%
§ We can combine the HTL process water rich in NH4 with PO4 in residue to produce struvite
§ Efficiencies recovery of ~90% P from incoming HTL feedstock
§ P is bioavailable
07/06/201916/01/2018
Much wider application
Other negative value feedstocs
• Industrial waste streams
• Municipal solid waste - organic fraction
• Waste wood
Once biocrude get accepted as a key ressource in the refinery
industry the economy will be fine for agricultural sidestreams if
credtis are taken into account
Summary
• It makes sense to go decentral
• Innovation is needed and it makes sense to take an engineeringapproach to bridge the gap between research and production
• Bio2Oil’s modular units are prone to become a game changer –
also in an European market
Big is beautiful
Small
Thank you for your kind attention
Support acknowledged with grattitude from
The Danish Innovation Fund - BioValue
Horizon 2020 – HyFlexFuel
Contact Info
Ib Johannsen
[email protected] /[email protected]
www.bio2oil.dk