The Energy InstituteEMS Energy Institute

Dimethyl Ether - A Path to Use Natural Gas as a Transportation Fuel

Dimethyl Ether - A Path to Use Natural Gas as a Transportation Fuel

André BoehmanEMS Energy Institute

Department of Energy & Mineral Engineering

The Pennsylvania State University

Partners:

Oberon Fuels

Alternative Fuel Technology, LLC

André BoehmanEMS Energy Institute

Department of Energy & Mineral Engineering

The Pennsylvania State University

Partners:

Oberon Fuels

Alternative Fuel Technology, LLC

The Energy InstituteEMS Energy Institute

Natural gas vehicles are of great public and commercial interest direct displacement of petroleum from a domestic resource

Efficient utilization of natural gas should be our goal But in what form? HCNG, CNG, LNG, or conversion to other fuel

chemistry for more efficient usage? Dimethyl ether represents an emerging engine technology for NG

utilization. Infrastructure build-out can piggyback on current LPG

infrastructure Handles like propane Burns smokeless eliminates diesel particulate matter concerns Won’t boil off if your vehicle sits for two weeks

Natural gas vehicles are of great public and commercial interest direct displacement of petroleum from a domestic resource

Efficient utilization of natural gas should be our goal But in what form? HCNG, CNG, LNG, or conversion to other fuel

chemistry for more efficient usage? Dimethyl ether represents an emerging engine technology for NG

utilization. Infrastructure build-out can piggyback on current LPG

infrastructure Handles like propane Burns smokeless eliminates diesel particulate matter concerns Won’t boil off if your vehicle sits for two weeks

Why Consider DME?Why Consider DME?

The Energy InstituteEMS Energy Institute

J. Eberhardt, DEER 2002

DME 61% the energy contentof propane

Similar energy contentto ethanol on volume basis

The Energy InstituteEMS Energy Institute

Vehicle Cycle THC (g/mi) NMHC (g/mi)

NOx (g/mi)

CO (g/mi) CO2 (g/mi)

PM (g/mi)

Btu/mi

RTD Bus 1014-CNG CBD 20.04 2.19 9.06 0.34 1690 0.02 27018

RTD Bus 1011-Diesel

CBD 0.18 ----- 16.12 11.18 1785 1.02 22908

Comparison of Emissions of Low Emissions Vehicle-Certified RTD Buses

McCormick, Graboski, Alleman, Herring and Nelson, SAE 1999-01-1507

CNG Vehicles Suffer From: Reduced compression ratio lower thermal efficiency

High unburned CH4 emissions

Combination of high CH4 emissions and reduced efficiency eliminates the H/C ratio benefit of CNG over diesel fuel with respect to CO2eq emissions

CNG Vehicles Suffer From: Reduced compression ratio lower thermal efficiency

High unburned CH4 emissions

Combination of high CH4 emissions and reduced efficiency eliminates the H/C ratio benefit of CNG over diesel fuel with respect to CO2eq emissions

~ 1890 g/mi at 10*GWP of CH4~ 2090 g/mi at 20*GWP of CH4~ 3090 g/mi at 70*GWP of CH4

The Energy InstituteEMS Energy Institute

1990’s: Thomas and Staunton (SAE 1999-01-1511) state DOE target is 10% > fuel

economy than equivalent gasoline vehicle, but > 15% improvements are possible with turbocharged lean-burn operation. Alternative is CI NG engines, using diesel pilot, and recommended port gas injectors or DI NG injectors, and maybe a prechamber to enhance ignition. Diesel efficiency requires DI or IDI for the NG and provide >28 to 37% efficiency gain over gasoline. Their analysis was restricted to conventional combustion – dual fuel with micropilot or CI of the NG.

Weaver and Turner (SAE 940548) show that knock can occur in high BMEP engines, leading to derating of the engine to avoid knock or reduction of the fraction of energy from NG. At light load the very lean mixture may prevent effective burning of the homogeneous NG charge unless the engine is throttled.

1990’s: Thomas and Staunton (SAE 1999-01-1511) state DOE target is 10% > fuel

economy than equivalent gasoline vehicle, but > 15% improvements are possible with turbocharged lean-burn operation. Alternative is CI NG engines, using diesel pilot, and recommended port gas injectors or DI NG injectors, and maybe a prechamber to enhance ignition. Diesel efficiency requires DI or IDI for the NG and provide >28 to 37% efficiency gain over gasoline. Their analysis was restricted to conventional combustion – dual fuel with micropilot or CI of the NG.

Weaver and Turner (SAE 940548) show that knock can occur in high BMEP engines, leading to derating of the engine to avoid knock or reduction of the fraction of energy from NG. At light load the very lean mixture may prevent effective burning of the homogeneous NG charge unless the engine is throttled.

CNG Vehicle EfficiencyCNG Vehicle Efficiency

Can we “burn” natural gas and have diesel or better efficiency? consider DME

Patron member

Patron member

Dimethyl-ether(DME)

Methane

Methanol

Water

Propane

Butane

Hydrogen Carbon Oxygen

1.4 tons MeOH to 1 ton DME

LPG

What is DME?DME Background -What is DME?

“Synthetic LPG”

DME Properties – Comparison with Other Fuels

Property DME Diesel Propane

Chemical Formula C2H6O C10.8 H18.7 C3H8

Molecular Weight 46.07 148.6 44.11

Critical Temperature- C 127 - 95.6

Boiling Point- C -24.9 71-193 -42.1

Vapor Pressure at 20 C-kg/m2 5.1 <0.01 8.4

Critical Pressure-bar 53.7 - 43

Liquid Viscosity- cP .15 2-4 .10

Liquid Density at 20 C-kg/m3 668 800-840 501

Bulk Modulus (N/m2) 6.37E+08 1.49E+09  

Specific Density,gas 1.59 - 1.52

Solubility in H2O at 20 C g/l 70 Negligible .12

Lower Heating Value- kJ/kg 28430 42500 46360

Heat of vaporization- kJ/kg 20C 410 233 426

Explosion limit in air- vol% 3.4-17 1.0-6.0 2.1-9.4

Ignition temperature at 1 atm- C 235 250 470

Cetane Number 55-60 40-55 -

7

88

Factors Driving DME Fuels Growth – Diesel Substitution

Opportunities

Can be used in conventional diesel engines with a modified fuel injection system

Large potential market High cetane Quiet combustion Clean burning (sootless – no

smoke or particulates) 100% SOx reduction

Challenges Technical and regulatory hurdles

remain LPG-like distribution infrastructure Lower lubricity requires lubricating

agent Lower viscosity can cause leakage Government regulations Volvo DME Truck

99

Factors Driving DME Fuels Growth – Diesel Substitution

Isuzu DME Diesel Truck Nissan NTSL DME Diesel Truck

SAIC DME Diesel Bus

Volvo DME Diesel Engine

Much Work Underway

Japan DME Vehicle Promotion Committee

Volvo & BioDME Consortium Shanghai Automotive Corp. Alternative Engine Technology Isuzu Advanced Engineering

Center Nissan

SAIC DME Diesel Engine

The Energy InstituteEMS Energy Institute

Developer of Novel Fuel Injection Systems for DME AFT fuel system technology is being adapted

for commercial heavy duty applications by Volvo Group and Delphi

AFT fuel system can be scaled from light-duty to heavy-duty applications

Developer of Novel Fuel Injection Systems for DME AFT fuel system technology is being adapted

for commercial heavy duty applications by Volvo Group and Delphi

AFT fuel system can be scaled from light-duty to heavy-duty applications

Technology DescriptionTechnology Description

Developer of Fleet Scale DME Production System DME at 3000-5000 gallons per day

Natural Gas and CO2 as feedstocks

Leaps over the “Valley of Death” due to small scale production

Developer of Fleet Scale DME Production System DME at 3000-5000 gallons per day

Natural Gas and CO2 as feedstocks

Leaps over the “Valley of Death” due to small scale production

R&D Support and Technology Demonstration Transportation Institute / Test

Track / Chassis Dyno Combustion, Emissions and Fuel

Formulation

R&D Support and Technology Demonstration Transportation Institute / Test

Track / Chassis Dyno Combustion, Emissions and Fuel

Formulation

Oberon Fuels Process

Biogas

Natural Gas + CO2

Syngas DMEMethanol

Gas-to-Liquids Unit

NG-DME

Bio-DME

Technology

• 30% CO2 in feedstock and scale are well suited for distributed waste biogas sources

• Innovations from Oberon focus on:– Integration of modular components– Process efficiency– Centralized volume construction

• Utilize proven components and catalysts• Benefit from the development of

small-scale hydrogen production units

World leader in DME fuel system innovation – developed four generations of common rail fuel systems specifically designed for DME

Novel fuel pumps and fuel injectorsNovel fuel feed pump to send fuel from the supply tank to the engine

The Energy InstituteEMS Energy Institute

Because it makes sense on many levels: Higher energy density than compressed natural gas Will not vent due to evaporation over time Does not need cryogenic storage Ease of refueling (no venting, no compressors) Diesel engine efficiency Ultra low emissions with simple emissions controls Monetizes “dry gas” in the Marcellus Shale

Natural gas is selling at less than $2.50 per equivalent diesel gallon (Jan. 2012, DOE Clean Cities Alternative Fuel Price Report

January 2012 DME is anticipated to sell at $3 per equivalent diesel gallon Represents an increase in the value of the natural gas

Because it makes sense on many levels: Higher energy density than compressed natural gas Will not vent due to evaporation over time Does not need cryogenic storage Ease of refueling (no venting, no compressors) Diesel engine efficiency Ultra low emissions with simple emissions controls Monetizes “dry gas” in the Marcellus Shale

Natural gas is selling at less than $2.50 per equivalent diesel gallon (Jan. 2012, DOE Clean Cities Alternative Fuel Price Report

January 2012 DME is anticipated to sell at $3 per equivalent diesel gallon Represents an increase in the value of the natural gas

Why Consider DME?Why Consider DME?

This team has the capability to bring DME and DME engines to market cost-effectively