Page 14 - AFVi CNG & LNG Participant Guide

Module 1: Properties and Characteristics of Natural Gas

Lesson 1.2: Properties and Characteristics of Natural Gas

Chemical Properties  90-96% methane
 Other components include ethane, propane, and butane
 Compared to gasoline, diesel, and propane, natural gas has the least carbon content,
which makes it a cleaner fuel going into the engine
 Chemical composition compared to gasoline and diesel
o Natural gas (methane) CH4
o Propane C3H8
o Gasoline C8H18
o Diesel C14H30

Physical Properties  Gaseous state
 Lighter than air (specific gravity <1)
 Colorless and tasteless
 Odorless (but odorants are added by utility company)
 Non-toxic
 Non-corrosive

Flammability  Ignition temperature 900-1080°F
Properties  Flammability range 5-15%
o <5% mixture is too lean to burn
o >15% mixture is too rich to burn

Emissions  Lower in carbon monoxide (CO)
Properties  Lower in hydrocarbons (HC)
 Lower in nitrogen oxides (NOx)
 Less greenhouse gas emissions (CO2)
 Zero particulates
 Zero evaporative emissions

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