synergistic effects of alcohol- based...

SYNERGISTIC EFFECTS OF ALCOHOL-

BASED RENEWABLE FUELS:

FUEL PROPERTIES AND EMISSIONS

by

EKARONG SUKJIT

1 School of Mechanical Engineering

1. Rationality

2. Research aim

3. Research outline

4. Methodology

5. Results

6. Conclusions

2

Presentation layout

• Environment concerns about emissions

• More stringent emission standards (THC, CO, NOx, PM)

• Use of energy from renewable sources

•10% for bio-fuel consumption in the transport section before 2020 (2009/28/CE)

• Alcohols can participate as an alternative fuel for ICE

• Benefit of oxygen in fuel molecules (reduce soot formation)

• Contribution of biofuels (produce from crop, waste biomass, crude glycerol,

algae etc.)

• Reduction in life-cycle green house emissions (lower C/H ratio, CO2 required

by production)

• Reduction in the dependence upon foreign oil in non-producing countries

• Used as fuel for vehicles (SI & CI engines)

However the blending of alcohols is limited because of its low

ignitability, lubricity, heating value and miscibility

3

Rationality. Why bioalcohols are needed?

European emission standards for (a) diesel passenger cars

(b) heavy-duty diesel engines

4

European emission standards

0.2 0.4 0.6 0.8 1.0

0.03

0.06

0.09

0.12

0.15

0

0

Euro 1 (1992)

Euro 2 (1996)

Euro 3 (2000)

Euro 4 (2005)

Euro 5 (2009)

Euro 6 (2014)

NOX emissions (g/km)

PM

em

issi

on

s (g

/km

)

2 4 6 8 10

0.1

0.2

0.3

0.4

0

0

Euro I (1992)

Euro II (1998)

Euro III (2000)

Euro IV (2005)

Euro V (2008)

Euro VI (2013)

NOX emissions (g/kWh)

PM

em

issi

ons

(g/k

Wh)

(a) (b)

Source: Lapuerta, M. (2010)

5

Rationality. Properties of alcohols

6

Rationality. Alcohol-diesel blends

Longer-chain alcohols (three

or more carbon) shows better

blending stability as a

consequence of their higher

polarity


Stability

7


The limitation of viscosity for diesel fuel is 2-4.5 cSt (40oC) based on EN590

Percentage of alcohols blended with diesel is limited by viscosity limitation

Ethanol: 22% , Propanol: 45%, Butanol and pentanol: No limitation


Viscosity

8


The limitation of wear scar diameter generated by diesel lubricity test is 460 µm

(60 oC) based on ISO 12156

Percentage of alcohols blended with diesel is limited by lubricity limitation

Ethanol: 92%, Propanol: 80%, Butanol: 35%, Pentanol: 10%


Lubricity

• Alcohols/diesel blends need some additives to restore their properties

such as blending stability, viscosity and lubricity.

• To meet this, biodiesel may be the alternative choice due to

• Miscibility in all ratios with diesel blends

• Good lubricity

• High viscosity

• Biodiesel refers to vegetable oil or animal fat consisting of long-chain

alkyl esters of fatty acids

• Vegetable oil or animal fat + alcohols → alkyl esters + glycerol

• Commonly methanol is used in tranesterification

• Most common fatty acid profile of biodiesel are palmatic acid (C16:0),

stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic

acid (C18:3)

9

Rationality. Why biodiesel is needed for alcohol-

diesel blends?

10

Fatty acid profile of vegetable oil

11

Fatty acid profile of vegetable oil

“ To extend the use of alcohol-diesel blends through the

biodiesel incorporation ”

With objectives to study:

• Effect of biodiesel on fuel properties of diesel blends

(emphasis on lubricity)

• Effect of molecular structure of biodiesel on alcohol-diesel

blends

• Carbon chain length

• Unsaturation degree (double bond)

• Hydroxylation

• Effect of hydrogen on alcohol blends

12

Research aim

13

Research outline

Density

Viscosity

Miscibility

Lubricity

Alcohol + Diesel

Low lubricity fuels

ULSD

GTL

Improved lubricity

Chapter 4

Molecular structureEngine test

Chain length Unsaturation

C12:0

C14:0

C16:0

C18:0

C18:0

C18:1

Hydroxylation

C18:1

C18:1OH

Chapter 5 Chapter 6

Improved soot-NOx trade off

Carbonaceous gas emissions (HC

& CO) from alcohol-diesel-

biodiesel are higher with respect to

pure biodiesel combustion

Hydrogen

No carbon atom

High flame speed

Improved HC, CO

and soot

Chapter 7Not compatible

with diesel fuel

specifications

Biodiesel

Biodiesel

Lubricity test

Rationality

14

Test fuels

15

Test fuels

• Modified HFRR (account for fuel evaporation)

• Deeper fuel holder

• Covered with a close-fitting PTFE lid

16

Methodology. Lubricity test

Upper specimen

Lower specimen

Heater block

Fretting flexure lock LVDT and flexure housing Electromagnetic vibrator

Counterweight

Force transducer

Main RTD location hole

(In far side of block)

Vibrator support extension

PTFE seal set

Fuel

• Single cylinder diesel engine

17

Methodology. Engine test Engine specification

Number of cylinders 1

Bore (mm) 98.4

Stroke (mm) 101.6

Connecting rod length (mm) 165

Displacement volume (cm3) 773

Maximum torque (N.m) @ 1800rpm 39.2

Maximum power (kW) @ 2500 rpm 836

Compression ratio 15.5:1

Injection timing (obTDC) 22

Maximum injection pressure (bar) 180

Injection system Three holes pump-

line-nozzle

Engine piston Bowl-in-piston

Engine operating conditions

Load: 3 and 5 bar IMEP

Speed: 1500 rpm

EGR: 0, 10% and 20%

18

Methodology. Experimental Installation

NI PCI-MIO 16E-4

Wiring box

Shaft encoder

KISTLER

5011

KISTLER

6125B

Charge

amplifier

Pressure

transducer

1-Cylinder

diesel engine

Electric

dynamometer

Fresh air inlet

Fuel injector

Intake

manifold Exhaust

manifold

Exhaust gas out

EGR valve

Emission

analysers

• Horiba MEXA 7100DEGR (HC, CO, NOx)

19

Methodology. Emission analyser

• Horiba MEXA 1230 (Soot, SOM)

20


•Scanning Mobility Particle Sizer (PM distribution)

21


• ThermalGravimetric Analysis (PM composition: VOM, soot

oxidation temperature)

22


Loaded Filter Sample Filter Holding Plate Filter Stopper

Filter Sample

23

Results

24

Heat release analysis

-10

0

10

20

30

40

50

-20 -10 0 10 20 30

Ignition

delay

Premixed

Combustion

Diffusion

Combustion

Late

Combustion

Crank angle degree (CAD)

Rat

e of

hea

t re

leas

e (J

/CA

D)

SOI SOC EOI EOC

25

Results. Biodiesel as lubricity enhancer

• Lubrication film concentration

• Friction coefficient

Upper specimen

Lower specimen

Microscope WSD

SEM & EDS Profilometer

Wear scar profile Microscopic topography

26

Results. ULSD-RME blends

100

150

200

250

300

0 10 20 30 40 50 60 70 80 90 100

Co

rrecte

d w

ea

r s

ca

r d

iam

ete

r (

µm

)

RME (% v/v)

274

200

188

214 217219

211208 206 206 204

27

Results. GTL-RME blends

100

150

200

250

300

350

0 10 20 30 40 50 60 70 80 90 100

Co

rrecte

d w

ea

r s

ca

r d

iam

ete

r (

µm

)

RME (% v/v)

290

196 202 203214 211

205216 212 217

204

28

Results. Biodiesel as lubricity enhancer

Low lubricity fuels

ULSD

GTL

Biodiesel (RME)

HFRR Profilometer

Fixed 70% GTL + ULSD + RME

G70D

G70D20R

G70D10R

ULSD GTL RME

D70G20R G70D20R0

5

10

15

20

ULSD GTL RME D70G20R G70D20R

Ca

rbo

n c

on

ten

t (%

)

SEM & EDS

29

Results. Effect of molecular structure of biodiesel on alcohol-diesel

blends: carbon chain length & unsaturation degree

•Lubricity test

E10D B16D E10R15D B16R15D

30


blends: carbon chain length & unsaturation degree

•Engine test

Alcohol + Diesel

Methyl esters

C12:0

C14:0

C16:0

C18:0

C18:1

Chain length Unsaturation

C18:0

C18:1

Chain length Unsaturation degree

THC

CO

NOx

Soot

Incresing

Increase

Increase

No clear trend

Increase

Decrease

Decrease

Increase

Decrease

Effect of molecular structure

Effect of alcohols

31


blends: hydroxyl group

60

80

100

120

140

440

460

480

500

Ener

gy (

kJ/m

ol)

Tem

per

atu

re (

o C)

Soot oxidation temperature Activation energy

Diesel Diesel+Butanol+RME

Diesel+Butanol+COME

Diesel+Butanol+RME

(C18:1)

Diesel+Butanol+

COME (C18:1 OH)

Density

Viscosity

Lubricity

Miscibility

Density

Viscosity

Lubricity

Miscibility

4

6

8

10

12

14

0.05 0.15 0.25 0.35 0.45

NO

X(g

/kW

h)

Soot (g/kWh)

Diesel

Diesel+Butanol+RME

Diesel+Butanol+COME

Improving

trade-off

32

Results. Effect of hydrogen on alcohol blends

Fresh air inlet

Fuel injector

Intake

manifold Exhaust

manifold

1-Cylinder diesel engine Exhaust gas out

EGR valve

Hydrogen

Emission analyser

33

Results. Effect of hydrogen on alcohol blends

Alcohol + Biodiesel

Hydrogen

Carbonaceous gas emissionsPM and NOx

H2 THC

H2 CO

H2 NOX

H2 PM

EGR NOX

34

Conclusions

Parameter THC CO NOX PM

Chain length

Unsaturation

degree

Hydroxyl group

Hydrogen

Decrease O2

Increase viscosity

Decrease O2

Increase viscosity

Decrease O2

Increase CN

Increase BM

Increase AFT

NOX

NOX

NOX

NOX

Decrease O2

Increase melting point

Increase viscosity

Decrease viscosity Decrease viscosity Increase BM

Decrease CN

Increase AFT

Decrease melting point

Decrease viscosity

Increase O2 THC

Increase viscosity THC

Increase O2 THC

Increase viscosity THC Decrease CN

Less soot

Increase O2

More potential of OH

Liquid fuel replacement Liquid fuel replacement High flame speed

Increase HO2 radicals

Liquid fuel replacement

Increase OH radicals

35

Thank you for your attention

School of Mechanical Engineering

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