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METHANOL-FUELED
ENGINES: STATE OF THE ART
AND FUTURE POTENTIAL Sebastian Verhelst
DEPARTMENT OF FLOW, HEAT AND COMBUSTION MECHANICS
TRANSPORT TECHNOLOGY RESEARCH GROUP
WHY METHANOL?
3
METHANOL AS A FUEL
1990s: CA methanol program, focused on improving air quality
> 17.000 M85 FFVs sold to public
Now: China main methanol fuel market
Improving air quality & increasing energy security
M5 up to M100, M15&M85 used most
Also large interest in marine (LNG alternative)
2015: 35 billion liters of methanol for energy use
Drop-in possibilities (e.g. EN228 – M3; “GEM blends” for FFVs)
Produced from fossil sources now, but also very interesting bio- or e-fuel
‒ Simplest fuel that is liquid at atmospheric conditions
‒ Liquid fuel that is most easily produced from renewables (wind, solar, …)
‒ H2 + CO/CO2 CH3OH
4
METHANOL (MeOH) AS AN ENGINE FUEL
5
PHYSICOCHEMICAL PROPERTIES
Higher H/C ratio vs. gasoline
specific CO2 emissions (gCO2/MJ) -7% (assuming equal engine effic.)
High Cp of burned products
Lowering peak T and heat losses
Higher laminar burning velocity (burns ~50% faster)
More knock resistant
Higher dilution tolerance
Oxygenate - oxygen constitutes 50m% of CH3OH
Low air/fuel ratio, lower energy content
Slightly lower mixture volumetric energy content
‒ Port Fuel Injection (PFI): P -5%, Direct Injection (DI) P +6%
OH group polar molecule…
6
PHYSICOCHEMICAL PROPERTIES
High heat of vaporization &low AFR:
energy needed to vaporize fuel
= 7 times that of gasoline
Low T throughout engine cycle
&low Tadiab lower wall heat losses, lower NOx
Increased knock resistance: compression ratio (CR)
can go up, optimal spark timing can be used
in wider area of engine map
Charge cooling: mixture‟s volumetric
energy density increases, P↑
Octane numbers: RON = 109, MON = 92 More knock resistant
7
C O
C
O
C
O
C
O
Thus methanol has an
‘effective’ molecular
weight of 128 – i.e. ‘liquid’
NUMBERS – “FFVs”
8
“FLEX-FUEL VEHICLES”: THEN
Note M85 was the fuel for which FFV technology was developed!
E85 only came later.
Note ability for the vehicle to operate on gasoline compromises
the engine design (e.g. compression ratio)
California methanol programme „90s: still, typically about 5%
increase in power and efficiency
Very similar to E85 results
Increased volumetric efficiency, more isochoric combustion,
lower heat losses, lower pumping losses
Remainder of presentation: methanol used pure, i.e. M100
9
“FLEX-FUEL VEHICLES”: NOW
Today‟s engine technology
Knock control ‒ Alcohols don‟t need spark retard at high loads,
ignition can be kept at optimal timing
Component temperature protection (turbine) ‒ No need for enrichment
Direct injection ‒ Making even better use of increased charge cooling
(cooled) Exhaust Gas Recirculation (EGR) ‒ Increased dilution tolerance
Increased potential for efficiency improvement at
highly loaded operation, i.e. downsized engines
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UGent RESEARCH
Converted engines on test bench
PFI “flexfuel”, VVT: relative to gasoline, efficiency
+10%, NOX up to -10 g/kWh (engine-out)
DI “flexfuel”: relative to gasoline, -20% CO2
Downsized engine (TC DI): In progress…
initial tests already showed up to 5 %pt higher
efficiency (+18% relative), NOx -35%
Further optimization ongoing, supported by
fundamental work on combustion
properties
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NUMBERS – “DEDICATED”
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PUSHING EGR DILUTION STRATEGY
L4, 1896cc, 2V, CR=19.5, PFI, TC, LPL EGR
i.e. VW AXR TDI converted to SI
Faster, more stable combustion
High CR, turbocharged
Hence, more dilution tolerance
Wider range for wide open throttle operation
(down to 3 bar BMEP)
Lower in-cylinder temperatures
Cooling & dissociation losses ↓
Knock/pre-ignition ↓
Engine-out NOX ↓
13
SAE 2012-01-1283
NOx (ppm)
RESULTS WOT EGR STRATEGY
WOT EGR: diesel-like peak efficiency
Vast engine-out NOx reductions (ppm), l=1 operation
14
42%
Diesel-like efficiencies
while using cheap
aftertreatment systems
WHERETO NEXT?
Ultimate potential dedicated engines?
Increased CR (but not 19.5), DI, TC …
High EGR rates: heat loss ↓ but combustion becomes unstable
Solution? Use other feature of methanol,
i.e. relative ease of fuel reforming
Remember methanol was also studied as a hydrogen carrier for fuel cell
vehicles (1 m³ of MeOH contains more H2 than 1 m³ of liquid H2!)
Thermal decomposition (TD): CH3OH CO + 2H2 Δh298K = +91 kJ.mol-1
Steam reforming (SR): CH3OH + H2O CO2 + 3H2 Δh298K = +49 kJ.mol-1
Waste heat recovery: drive reforming using exhaust heat
+ fuel reforming to support high dilution (faster burning due to H2)
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M.I.T. CONCEPT
Cfr. alcohol for ORC
“Use fuel as ORC working fluid
but ditch condensor, turbine”
“vs. gasoline PFI: +50% h”
“vs. diesel truck engine: +20-25%”
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Bromberg L, Cedrone K, Cohn DR, 20th ISAF, 2013
Super -efficient Spark Ignition Methanol Engines
Effic
iency g
ain
rela
tive to
sta
ndard
gasolin
e e
ngin
e
20%-
10%-
Removal of knock limit
(higher octane)
50%-
40%-
30%-
exhaust heat recovery
High compression ratio
Turbocharging and downsizing
Diesel engine
55%-
Exhaust heat recovery
Super Efficient Spark Ignition Methanol Engines
Source: MIT
CURRENT METHANOL PROJECTS
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ON-ROAD
Actual use & demo‟s, e.g.:
China
Light & heavy duty
(SI / Dual Fuel CI)
MeOH: 8% of fuel pool
Israel
M15 demo
Australia
No tax on MeOH fuels,
GEM demo
Europe
GEM fuels in Junior WRC
Research projects, e.g.:
Lulea Univ: MeOH production,
vehicle demo
Lund Univ: high efficiency CI MeOH
concepts
Ghent Univ: high efficiency SI MeOH
concepts, GEM blend tests
U.S.: Co-optima – engine-fuel combo
for highest efficiency
18
GEM concept: gasoline/ethanol/methanol
blend with same air/fuel ratio as E85
drop-in fuel for FFVs
MARINE
Stena Germanica
Ferry Kiel-Gothenburg, medium speed
engines
Stena, Wärtsilä, ports, Methanex
In operation
LeanShips
WP05: conversion of high speed
marine diesel engine to dual fuel
operation on methanol
Ghent University, Damen Shipyards,
Abeking&Rasmussen, Kant
Marine&Industry (~Volvo Penta),
Methanex Europe, Dredging Int.
2015-2019
GreenPilot
Pilot boat conversion
Swedish Maritime Tech Forum,
ScandiNAOS, SSPA, Swedish
Transport & Maritime Administrations
2016-2018
MethaShip
Medium speed engines, for cruise
vessels and RoPax ferries
Meyer Werft, Flensburger, Lloyds
Register (ass. partners: Caterpillar,
Helm, MAN)
2014-2018
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LEANSHIPS
EU Horizon 2020 Mobility for Growth „innovation action‟
40 partners, 7 demonstrator platforms
UGent: WP05 leader “Demonstrating the potential of methanol as
an alternative fuel” (6 partners)
Conversion of high speed marine diesel engine
to dual fuel operation with methanol
‒Map power, efficiency, emissions
LCA of methanol in shipping
Tools for dissemination and market uptake (pilots)
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CONCLUSION
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CONCLUSION
Methanol is a compelling alternative fuel:
From a production and use point of view…
It‟s liquid; already available (fossil), and can be produced from renewables
Can be blended in (gasoline/ethanol) or used in Dual Fuel (diesel engines)
And methanol is a great engine fuel
Potential for efficiencies exceeding those of diesel engines, with the
low emissions of gasoline engines (using simple aftertreatment), and
with greater performance than both (actual potential still to be proven)
Further boost of (part-load) efficiency through fuel reforming
‒ Waste heat recovery + push dilution (even) further… Work in progress…
Already in the market, + research & demo‟s ongoing
22
Sebastian VERHELST Associate Professor of Internal Combustion Engines
DEPT. OF FLOW, HEAT AND
COMBUSTION MECHANICS
T +32 9 264 33 06
www.ugent.be/ea/floheacom
Ghent University
@ugent
sebastian-verhelst-0398959
BACKUP SLIDES
24
MYTHS&MISCONCEPTIONS
“too corrosive”
Polarity also means MeOH is more corrosive than gasoline
Light metals can be affected by pitting, nylons swell
Well understood and tackled by using compatible materials
<150$ to make a new car methanol compatible
“toxic!”
Yes, so is gasoline… even when gasoline prices were lower than water prices, we
didn‟t need to take actions to prevent people from drinking it…
“dangerous – burns with invisible flame!”
E.P.A. estimated that if all cars ran on methanol rather than gasoline, vehicle fires
would be reduced by 90% (MeOH harder to ignite, less heat radiation, …)
“will contaminate water supplies!”
Methanol is ubiquitous in the environment, and readily bio-degradable. The half-life
for methanol in groundwater is just 1 to 7 days, while e.g. benzene is 10 to 730 days.
Methanol is actually a more environmentally benign fuel than gasoline.
25
CALIFORNIA METHANOL PROGRAMME
Courtesy of Paul Wuebben, CRI
> 17.000 M85 FFVs sold to public
Max fuel volume throughput: 7.5 M liters/month
10 OEMs involved
Toxicity? In the CA Fuel Methanol Program, with over 200
million miles of consumer experience, there was not a single
documented harmful event
By the way, existing commercial products contain significant
amounts of methanol (e.g. windshield washer fluid)
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HYDROGEN VECTORS
27
0
20
40
60
80
100
120
140
Ma
ss
of
Hyd
rog
en
per
m3
of
Co
mp
ou
nd
/ [
kg
] a
nd
Ch
an
ge
ve
rsu
sL
iqu
id H
yd
rog
en
/ [
%]
Mass of Hydrogen per m3 Percentage Increase over Liquid Hydrogen
INTRODUCING METHANOL?
28
HOW TO INTRODUCE METHANOL?
Most successful biofuel presently: bio-ethanol
Which is being used: Mixed into gasoline, in low concentrations (E5, E10)
In high concentrations (E85) in “flex-fuel vehicles” (FFVs)
EtOH lion share of the ~4% share of biofuels in transport,
~40M FFVs worldwide
MeOH miscible with gasoline+EtOH
Hypothesis: gasoline-EtOH-MeOH
blends ~ identical properties to E85
(GEM blends) can be used by FFVs
29
SAE 2011-24-0113
REQUIREMENTS FOR „DROP-IN FUELS‟
30
Turner et al. IMechE
SVT Conference, 2012
WORK ON GEM BLENDS
Experiments on various alcohol blends
(gasoline / methanol / ethanol)
Results indeed identical to E85
i.e.: better efficiency than gasoline, lower (NOx) emissions
Fundamental research into combustion properties
i.e. methanol can be introduced as blend component in drop-
in fuels, i.e. TODAY!
31 Sileghem et al. Fuel 117:286-293
32
72.0 72.0 72.0
15
37 37 37 37
85
21 21 21 21
42 42 42 42
0
10
20
30
40
50
60
70
80
90
100
Gasoline Gasoline Gasoline A C C C C
Blend Designation
Vo
lum
es f
or
Eq
ual
En
erg
y / [
Vo
lum
e U
nit
s]
Gasoline Ethanol Methanol
GASOLINE DISPLACEMENT FOR BLEND C
Equivalent Energy on Each Side
=
72x3+15 = 231 37x4 = 148
36% less gasoline