CNI BENEFITS ON ENGINE

OVERVIEW

What is Cetane Number?

How do we improve Cetane Number?

How does Cetane Number impact engine operation?

WHAT IS CETANE NUMBER

Cetane number is a numerical representation of the ignition delay of a given fuel

• The number is defined as the equivalent % n-Cetane (n-Hexadecane) in a blend with α-methylnaphthalene

n-Cetane has a CN of 100

α-methylnaphthalene has a CN of 0

Due to difficulties working with α-methylnaphthalene, it was replaced with heptamethylnonane

Heptamethylnonane has a CN of 15

n-Cetane (n-Hexadecane)

α-methylnaphthalene

Heptamethylnonane

CN = % N-cetane + 0.15 (% Heptamethylnonane)

HOW DO WE IMPROVE CETANE NUMBER –PHYSICAL DELAY

Physical delay is influenced by:

Density and temperature of air in cylinder

Velocity and turbulence of air

Atomization, penetration and shape of fuel spray

Properties of fuel:

Density

Viscosity

Surface tension

Specific heat

Heat of vaporization

Vapor pressure

Vapor diffusivity

HOW DO WE IMPROVE CETANE NUMBER –CHEMICAL DELAY

Chemical delay is influenced by rate of free radical formation

Fuel is heated to high temperature where weaker bonds break, forming free radicals

Once a sufficient concentration of free radicals is reached, combustion occurs

Cetane Number Improvers increase rate of free radical production

HOW DO WE IMPROVE CETANE NUMBER –CETANE NUMBER IMPROVER

2-ethylhexyl nitrate (CI-0801)

Most widely used CNI

Di-tert-butyl peroxide (CI-0808)

Nitrogen content of fuel is limited eg. CARB

Relative effectiveness of 75% vs 2-EHN

More expensive than 2-EHNRange of Cetane improvement in middle distillate fuels using CI-0801

EFFECT OF CRUDE OIL SOURCE ONDIESEL FUEL COMPONENT QUALITY

Light Gasoil

ex Arab Light

Crude

Light Gasoil

ex Forties

Crude

Light Gasoil

ex Nigerian

Crude

Light Gasoil

ex Venezuela

Crude

Cut Point, °C 235 - 280 235 - 280 235 – 280 235 - 280

Density,

g/cm3

0.8259 0.8368 0.8757 0.8439

Sulphur, wt% 0.72 0.09 0.11 0.32

Cetane Index 53.5 49.5 37.7 50.1

Cetane

Number

54.3 52.2 41.3 50.4

EFFECT OF PROCESS UNIT TYPE ON DIESEL FUEL COMPONENT QUALITY

Non

Hydrotreated

LCGO

Hydrotreated

LCGO

Hydrocracker

Gasoil

Coker Gasoil

Cut Point, °C 205 - 343 205 - 343 205 - 343 205 - 343

Density, g/cm3 0.9613 0.9294 0.8498 0.9196

Sulphur, wt% 1.35 0.24 0 Crude dependent

Cetane Index 23.4 28.4 56.0 36.1

Cetane Number 21.0 24.1 57.8 32.6

EFFECT OF DISTILLATION CUT ONDIESEL FUEL COMPONENT QUALITY

Heavy Naphtha

ex Forties

Crude

Light Kerosene

ex Forties

Crude

Heavy

Kerosene ex

Forties Crude

Gasoil ex

Forties Crude

Cut Point, °C 150 - 190 190 - 235 235 - 280 280 - 343

Density, g/cm3 0.7870 0.8136 0.8368 0.8614

Sulphur, wt% 0.01 0.03 0.09 0.21

Cetane Index 35.5 44.1 49.5 50.6

Cetane

Number

37.8 46.0 51.7 54.9

CETANE NUMBER AND ENGINE OPERATION

Shorter ignition delay improves several factors of engine operation

Improved cold-weather starting

Less white smoke at start-up

Shorter warm-up time

Lower emissions

Decreased noise

Increased engine durability

Possible fuel economy improvement

0.00

0.20

0.40

0.60

0.80

1.00

1.20

36 40 44 48 52 56

Hyd

roca

rbon

g /b

hp-h

r

Cetane number

Without CNI

With CNI

EFFECT OF CN ON HC EMISSIONS

1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

2.60

2.80

3.00

38 40 42 44 46 48 50 52 54 56

CO

em

issi

ons,

g/b

hp-h

r

Cetane Number

Without CNI

With CNI

EFFECT OF CN ON CO EMISSIONS

5.40

5.60

5.80

6.00

6.20

6.40

6.60

6.80

38 40 42 44 46 48 50 52 54 56 58

NO

x E

mis

sion

, (g/

kWh)

Cetane Number

Without CNI

EFFECT OF CN ON NOX EMISSIONS

1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

2.60

2.80

3.00

38 40 42 44 46 48 50 52 54 56

CO

em

issi

ons,

g/b

hp-h

r

Cetane Number

Without CNI With CNI

EFFECT OF CN ON PARTICULATE EMISSIONS

0

20

40

60

80

42 46 50 54 58

Whi

te S

mok

e (%

)

Cetane Number

Without CNI

With CNI

EFFECT OF WHITE SMOKEIN A DI DIESEL ENGINE

5.40

5.60

5.80

6.00

6.20

6.40

6.60

6.80

38 40 42 44 46 48 50 52 54 56 58

NO

x E

mis

sio

n, (

g/k

Wh

)

Cetane Number

Without CNI

With CNI

Expon. (With CNI)

THE EFFECT OF CNI AND TEMPERATUREON ENGINE NOISE AT IDLE (900 RPM)

ECOCLEAN® TECHNOLOGY

To improve the performance of diesel fuel in modern-day diesel engine systems

Corrosion Inhibition

CetaneNumber

Thermal Stabili-zation

Detergency/Dispersancy

Dehazing/

Demulsifi-

cation

Antifoam

EXHAUST PIPE VIDEO

May 12, 2017 ©2016. Innospec, Inc. All Rights Reserved 18

SUMMARY

Cetane number is a measure of ignition quality of middle distillate

fuels

Increased Cetane number has positive impact on engine operation

Cetane Number Improvers (CNI) can be utilized to improve ignition

quality in low Cetane fuels