Page 15 - AFVi CNG & LNG Participant Guide

Module 1: Properties and Characteristics of Natural Gas

Lesson 1.3: How Natural Gas Compares with Liquid Fuels

Properties of
Natural Gas Property Gasoline Diesel Natural Gas
Compared with Source Petroleum Petroleum Natural Gas
Gasoline and Diesel Physical State Liquid Liquid Gas

>1 >1 <1
Vapor Density
Heavier than air Heavier than air Lighter than air
Ignition 580°F 410°F
Temperature 900-1,080°F
Flammability Range 1.4-7.7% .6-7.5% 5-15%

5.66 pounds GGE
Weight 6 pounds 7 pounds
6.4 pounds DGE
BTU Content/ 125,000 140,000 125,000 per GGE
Gallon or GGE/DGE 140,000 per DGE
Octane Rating 85-94 N/A 130
Cetane Rating N/A 40-60 <0

What is Octane?  Rating for the ability to resist detonation
o The higher the number, the higher the temperature required to ignite the fuel

What is Cetane?  Rating of speed at which fuel begins to combust
o The higher the number, the faster (easier) the ignition begins

What Technicians  Because natural gas is lighter than air, it rises when leaked and dissipates rapidly
Need to Know  Natural gas will only burn in concentrations of 5-15% in air

How CNG Compares
to Gasoline and Property Gasoline Diesel CNG
Diesel
Transportation and Transported to Truck Truck Transmission or
Storage Fueling Stations Distribution Pipelines
Stored at Fueling Underground Underground Above ground ASME
Stations storage tanks storage tanks pressure vessels

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