Compressed Natural Gas as a Vehicle Fuel

Copyright 2004 AFVI This material is intended to be used for in-house trainers of NGV fleet operators to train drivers and other interested parties on how to safely fuel natural gas vehicles. The material may not be used to develop or deliver commercial training programs or for any purpose other than stated above.

Drivers Need to Know  Introduction to natural gas  Why CNG as a vehicle fuel  Properties and characteristics of CNG  CNG fueling station safety practices  Fueling station safety equipment  Emergency procedures  Safe vehicle fueling procedures

Module 1 IntroductiontoCompressed Natural Gas

Module 1 Learning Objectives  Understand why natural gas as a vehicle fuel  Understand where natural gas comes from  How natural gas is delivered to a CNG fueling station  Environmental benefits

Why CNG?  Domestically produced  Large existing underground distribution network in place  Large installed base of vehicles in U.S.

Why CNG? - 2  Clean air benefits – 66% less carbon monoxide (CO) – 68% less non-methane hydrocarbons (NMOG) – 87% less oxides of nitrogen (NOx) – 40% less particulate matter (PM10)

Why CNG? - 3  Does not contaminate ground water or soil  Is an EPAct alternative fuel

Module 2 PropertiesandCharacteristics of CNG

Module 2 Learning Objectives  Understand natural gas and how it compares to other fuels  Be familiar with the characteristics of natural gas  Understand potential health and safety hazards

Physical Properties  Natural gas occurs underground and may be mixed with petroleum.  Chemical composition – Mixture of methane, ethane, propane and butane – Natural gas is mostly (85% to 96%) methane

Compared to Other Fuels Natural Gas CH 4 Propane C3H8C3H8 Gasoline C 8 H 30 Diesel C 14 H 30 Biodiesel (Palmitic) C 15 H 31 CO 2 CH 3 Methanol CH 3 OH Ethanol CH 3 CH 2 OH

Specific Gravity  (air = 1)  Since natural gas is lighter than air it rises when released into the atmosphere  Both the fuel and vapors of Biodiesel, E85, and Propane are heaver than air

Appearance & Smell  Colorless and tasteless  Odorless (but odorants are added for safety)

Health & Safety Hazards  Non-toxic  Simple asphyxiant – Inhalation is primary route of exposure – Overexposure symptoms: shortness of breath, unconsciousness  CPR recommended to overcome over exposure

Physical State  Compressed to allow maximum fuel storage – 3000 or 3600 psi  Measured for sale in mass weight – 5.66 pounds = 1 gasoline gallon equivalent (GGE)  CNG is 117 octane fuel

Flammability  Burns with a pale, faintly luminous blue flame at 1100° F – Gasoline 630 o F – Diesel 125 o F  Fuel-to-air ratio is 4% (LFL) to 16% (UFL) – Gasoline 1.3% (LFL) to 7.6% (UFL) – Diesel.3% (LFL) to 10% (UFL)

Fire Extinguishing  Fire extinguisher(s) located at or near the dispenser  If flame is extinguished without stopping gas flow, air/fuel mixture may reignite  Use a fire extinguisher only if properly trained to do so by qualified person

Module 3 CNG Fueling Station Equipment

Module 3 Learning Objectives  Understand different types of fueling stations  Be familiar with various components of a CNG fueling station

Types of Fueling Stations  Time - Fill – Time - fill dispenser Example: school bus

Types of Fueling Stations - 2  Time - Fill – Refueling appliance FuelMaker: Individual vehicle or small fleets

Types of Fueling Stations - 3  Cascade Fast - Fill – Cyclical fueling patterns – Public fueling

Fueling Station Components  Gas dryer  Compressor(s)  CNG storage  Dispenser(s)

Fueling Station Components - 2  Card reader  Emergency shutdown system  Fire extinguisher

Module 4 Emergency Action Plan

Module 4 Learning Objectives  Know purpose and content of Emergency Action Plan  Be familiar with emergency equipment  Understand emergency actions

Purpose of Emergency Action Plan  Identification of emergencies  Action items  Notification procedures  Evacuation procedures  Safety systems  Emergency event action items

Facility Layout  Compressor  CNG storage tanks  Emergency Shutdown Devices (ESDs)  Fire extinguishers

Facility Layout - 2  Pre-planned evacuation route  Designated assembly area(s)  Street address of facility

Safety Practices  Emergency telephone numbers – Fire department – Emergency medical help – Police – Maintenance – Adjoining facilities  Safety Signs

Safety Practices – 2  Equipment Inspection: – Defective equipment Dispenser hoses Fueling nozzle and receptacle – Report unsafe conditions to maintenance technician or station attendant

Safety Practices – 3  Cell phones and static discharge danger – CNG/air mixture is flammable like gasoline vapors – CNG Fueling system is sealed, so there is no air in the fuel system at the station or on the vehicle – Nevertheless, it is advisable to turn off/do not use cell phone during vehicle fueling  Do not re-enter vehicle during fueling

Fire Safety Rules  Keep ignition sources away from fuel  Do not light matches or smoke cigarettes  Do not use cell phones while fueling vehicle

Gas Release at Dispenser  Close nozzle valve  Turn dispenser quarter turn shut-off valve to the off position  Disconnect fueling nozzle from vehicle and re-attach to mounting bracket on dispenser  Report situation to facility maintenance and/or station attendant

Fire Involving CNG  Evacuate immediate area of fire  Press ESD button  Prevent other people from entering the danger zone  Do not attempt to extinguish CNG fire without training

Fire During Vehicle Fueling  Do not attempt to disconnect fueling nozzle from vehicle  Direct others to evacuate immediate area  Press ESD button  Call fire department

Combustible Debris Fire  Press ESD button  Extinguish only if trained and it is safe to do so  Near equipment, extinguishing should be attempted only by qualified fire fighters

Module 5 Correct Use of Safety Equipment

Module 5 Learning Objectives  Understand how to correctly operate safety equipment – Fire extinguisher – Emergency shut-down device

Correct Use of Safety Equipment  Fire Extinguisher – Located on or adjacent to fueling island – Used to eliminate air (oxygen) from fire – Driver must be properly trained to fight (extinguish) a natural gas fire

Correct Use of Safety Equipment - 2  Emergency shut-down device (ESD) – Located on or adjacent to fueling island – Activation will close at least two isolation valves, causing the compressor and gas flow from storage to the dispenser to stop

Module 6 NGV Technology and Safety Features

Module 6 Learning Objectives  Understand how natural gas vehicles (NGVs) work  Understand how NGVs differ from gasoline and diesel powered vehicles  Be knowledgeable about the four types of on-board fuel storage cylinders

CNG Fuel System  Fuel receptacle: Flow fuel from dispenser nozzle into fuel storage cylinders  High-pressure fuel lines: flow CNG from fuel storage cylinders to pressure regulator  Manual quarter turn shut-off valve: can stop the flow of CNG from the fuel storage cylinders to the pressure regulator

CNG Fuel System - 2  Pressure regulator: Provides fuel pressure regulation to the fuel injectors  Fuel injectors: Flow CNG into the engine cylinder for combustion

NGVs vs. Gasoline & Diesel Vehicles  NGVs have sealed fuel systems – No air or oxygen in fuel system  Vehicle fuel is in a gaseous form – If fuel leaks, vapors will float upward  Vehicle fuel requires 1100 o F to ignite – High temperature not usually available

On-Board Fuel Storage System  Fuel storage cylinder types: – Type 1: All metal (steel or aluminum) – Type 2: Hoop-wrapped steel or aluminum – Type 3: Fully-wrapped steel or aluminum – Type 4: All composite (non-metallic)

On-Board Fuel Storage System - 2  CNG fuel storage cylinder useful life is 15 years from date of manufacture  Visual inspection required by NHTSA at 36,000 miles or 36 months  Fuel storage cylinders hold CNG at 3,000 or 3, o F

Module 7 How to Fuel a CNG Vehicle

Module 7 Learning Objectives  Be familiar with fueling instructions  Understand fueling nozzle/receptacle operation

Fueling Instructions  Open the fuel door and remove the protective cap on the vehicle fuel receptacle  Remove the fueling nozzle from the dispenser  Inspect the fueling hose and nozzle for damage  Place the nozzle on the receptacle and pull back to insure it is secure

Fueling Instructions - 2  Turn fueling valve handle on the nozzle to open position  Swipe fueling card through card reader  Turn dispenser fueling handle to the on position  After fuel stops flowing, turn dispenser fueling handle to the off position

Fueling Instructions - 3  Turn fueling valve handle on the nozzle to the vent position  Remove the nozzle from the receptacle and place it back on the dispenser  Replace the protective cap on the vehicle fuel receptacle

Fueling  Nozzle operation  Receptacle characteristics

Fueling - 2  NGV 1 nozzle – Type 1 – Typical public fueling nozzle

Fueling - 3  NGV 1 nozzle – Type 2 – Typical fleet fueling nozzle