PennStateDept. of Chemical Engineering113 Fenske LabUniversity Park, PA 16802

Goal: Quantify and characterize fuel system interactions and

elastomer compatibility with dimethyl ether

Performance Cost

Ease of UseEngine Compatibility

Without sacrificing

Dr. Kimberly WainDr. Joseph PerezDr. Wallis Lloyd

Alternative FuelsDimethyl Ether Rheology and Materials Studies

How much petroleum is the world consuming? According to DOE…

N. America

Western Europe &AustrailaEurasia

Central & S.AmericaAfrica

Middle East

Other1.85% of worldoil in US

Where is the world’s oil located?(proven reserves)

US has extremely limited proven oil reserves, imports

Developing countries will require massive resources

Petroleum Outlook

Million barrels per day

DevelopingAsia

OtherDeveloping

0

10

20

30

40

OtherIndustrialized

Nations

NorthAmerica

EE/FSU

U.S. Diesel Emissions Regulations

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 2 4 6 8 10 12

NOx Emissions (g/bhp*hr)

Parti

cula

te M

atte

r (g/

bhp*

hr)

1984

19881990

1991

1994199820042007

Trade off- reducing NOx, usually increases PM

To achieve emission goals:

Combustion designAfter-treatment systems

Electronic controlsAlternative fuels

S and P in fuel(also regulated)

catalyst poisons!

Combo

Fuel Studies at PSU

Diesel Fuels

Biodiesel Fuels

Dimethyl Ether

+ ROH catalyst

Hydrocarbon Syngas DME

Distillation Hydrocarbon mixture

Soybeans

Petroleum cut boiling ~282-338oC

LSDF 325 ppm SULSDF < 15 ppm S

Blends of methyl esters made from vegetable oils- renewable!No sulfur, phosphorus content

Converted biomass- renewable!Zero emission fuel, gas at STP

Viscosity Improvement

Raise to ASTM lower limit(DME)

Elastomer Durability

Fuel Injector Lubrication

Mimic fuel injector response

How alternative fuelseffect physical properties

DME Areas Investigated

Viscometry

Pressurizable design

Small capillary for enhanced accuracy

Adaptable Swagelock® fitting at fill port

Test Matrix

Typical viscosity improving additivesEnvironmentally friendly additives

Blends of DME and diesel- with and without additivesBlends of DME and biodiesel- with and without additives

Principle: Time for a certain volume of liquid tomove through a calibrated capillary

VLHtgD

12810 46πυ =

Viscometer Data

0.00

1.00

2.00

3.00

4.00

5.00

6.00

0 20 40 60 80 100wt % DME

Visc

osity

(cSt

)

ULSDF 25CULSDF 40CBiodiesel 25CBiodiesel 40C 4.1 cSt

1.9 cSt

ASTM #2 Diesel Viscosity Specs. at 40oC

Dramatic decrease in viscosity with addition of DME in small quantities

Two temps so responsecan be extrapolated

TraditionalPolymethacrylate- Long chain ester (OFM, VI)

Olefin Copolymer- Ethylene/propylene non-conjugated diene (VI)

Alcohol- Ethoxylated long chains (OFM)

Synthetic

Poly-a-olefin- PAO-40 “40” refers to kinematic viscosity at 100 oC (VI)

Environmentally Friendly

Vegetable Oil- Heat modified (polymerized) soybean oil (OFM)Vegetable Oil- Mixed fatty acids (OFM, VI)Vegetable Oil- Oleic acid alternative (OFM, VI)

Additives Used

Additive Effect

1 and 5 wt % concentrations tested in 25 wt % DME

0.0

1.0

2.0

3.0

4.0

5.0

6.0

40

Temperature (oC)

Vis

cosi

ty (c

St)

25% DME-ULSDF 25% DME-Biodiesel1% PMA ULSDF 5% PMA ULSDF1% PMA Biodiesel 5% PMA Biodiesel1% OCP ULSDF 5% OCP ULSDF1% OCP Biodiesel 5% OCP Biodiesel1% Ethoxy ULSDF 5% Ethoxy ULSDF1% Ethoxy Biodiesel 5% Ethoxy Biodiesel1% HEAR Oil ULSDF 5% HEAR Oil ULSDF1% HEAR Oil Biodiesel 5% HEAR Oil Biodiesel1% PAO-40 ULSDF 5% PAO-40 ULSDF1% PAO-40 Biodiesel 5% PAO-40 Biodiesel1% Mixed FAs ULSDF 5% Mixed FAs ULSDF1% Mixed FAs Bio 5% Mixed FAs Bio1% HT Soy ULSDF 5% HT Soy ULSDF1% HT Soy Bio 5% HT Soy Bio

ASTM #2 Diesel Viscosity Specs. at 40oC

4.1 cSt

1.9 cSt

Material Compatibility

Elastomer Durability

Chosen materials represent major types commercially available:

Buna-nSiliconViton

PolyurethaneTeflon

Kalrez (fluoro-polymer)

Expensive specialty polymer with high chemical resistance

ME tested 1) right out of pressure vessel and 2) after diffusion of DMout of o-ring (temporary versus permanent damage)

Buna-N Fuel Response

Strength loss is temporary and likely due to partial solvency of fuel in elastomer Extended exposure leads to performance compromise in DME

Kalrez Fuel Response

Strength loss is permanent and likely due to rupture of crosslinkingExtended exposure leads to deterioration in DME

Fuel Injector Wear

Bench Testing

Goal: Faster, less expensive test that accuratelypredicts fuel injector behavior

Modified Cameron-Plint wear tester

Pressurizable housing

Utilizes parts duplicating actual injector parts:- Same geometry as diesel injector- Same surface roughness and materials- Operates at typical or higher frequency

Total costs per test: ~$250 vs. $5000 for full engine testTotal operational time: 3 hrs. vs. weeks for engine test

Significant savings!

Cameron-Plint Device

Test Pins

Modified Cameron-Plint

Variable speed motor, 0-50 Hz

Fully simulates injector motion

Matching outer cylinder per pin

Capable of 2 tests /cylinder 1 per pin

New

DMEDME-

Scuffed

Fuel Injector Pin

Pin travel distance: 1mm

Wear Scar Mapping

MicroXAM™ Surface Mapping Microscope

Wave/light interference generates a horizontal light plane which is used as a surface probe

Successive intersections between the probe plane and the sample are the relief level curves

Pros: Fast image acquisition Easy to useRobust technique

Cons: Res. limit ½ wavelength of light sourceCurvature problematic

Wear Scar Examples

75 wt % DME/25 wt % ULSDF

Scar flattened, curvature removed

Wear Area

Depth of scar α severity of wear

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

0 500 1000 1500 2000 2500 3000

Length Position (mm)

Surfa

ce H

eigh

t (m

m)

Data confirms trend of incr. wear with incr. [DME]

Unworn height

Discrimination between ULSDF and biodiesel blends possible

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

1.600

1.800

0 20 40 60 80Wt % DME

Tota

l Wea

r Dep

th (

m)LSDFULSDFBiodiesel70 wt % Bio/5 wt % PMA70 wt % ULSDF/5 wt % PMA

Increasing wear scar depth with increasing [DME]Additives caused deeper scar: cycled fuel mixture=shearing of additives

chemical corrosion; 3 body wear

3 hours40 Hz150psi HeStatic test fluid

Cameron-Plint Data

Summary

Viscosity Material Compatibility

Fuel Injector Wear

Alternative Diesel Fuel Understanding

Acknowledgments

The Pennsylvania State UniversityDept. Of Chemical Engineering

113 Fenske Lab(814) 863-4537

Funding provided by:

Air Products Inc.C & K Technologies, Ltd

Caterpillar Inc.Dept. of Energy

National Science Foundation

Technical Support:

Argonne Nat’l LabUSDA Labs, PeoriaBritish PetroleumCannon Instr. Co.

Contributors:

Don Stiver, PSUDr. Bob Manning, Consultant

CAPTAIN – Is Port Left or Right?

THANKS - CAPTAIN JOHN