Compressed Natural Gas as a Vehicle Fuel. Copyright 2004 AFVI This material is intended to be used...
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Transcript of Compressed Natural Gas as a Vehicle Fuel. Copyright 2004 AFVI This material is intended to be used...
Copyright 2004 AFVICopyright 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 KnowDrivers 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 1Module 1Learning ObjectivesLearning 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?Why CNG?
Domestically produced
Large existing underground distribution network in place
Large installed base of vehicles in U.S.
Why CNG? - 2Why 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)
Module 2Module 2Learning ObjectivesLearning 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 PropertiesPhysical 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 FuelsCompared to Other Fuels
Natural Gas CH4
Propane C3H8
Gasoline C8H30
Diesel C14H30
Biodiesel (Palmitic) C15H31CO2CH3
Methanol CH3OH
Ethanol CH3CH2OH
Specific GravitySpecific Gravity
.55 - .65 (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 & SmellAppearance & Smell
Colorless and tasteless
Odorless (but odorants are added for safety)
Health &Health &Safety HazardsSafety Hazards
Non-toxic
Simple asphyxiant
– Inhalation is primary route of exposure
– Overexposure symptoms: shortness of breath, unconsciousness
CPR recommended to overcome over exposure
Physical StatePhysical 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 Flammability
Burns with a pale, faintly luminous blue flame at 1100° F
– Gasoline 630o F
– Diesel 125o 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 ExtinguishingFire 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 3Module 3Learning ObjectivesLearning Objectives
Understand different types of fueling stations
Be familiar with various components of a CNG fueling station
Types of Fueling StationsTypes of Fueling Stations
Time - Fill– Time - fill dispenser
• Example: school bus
Types of Fueling Stations Types of Fueling Stations - 2- 2
Time - Fill– Refueling appliance
• FuelMaker: Individual vehicle or small fleets
Types of Fueling Stations Types of Fueling Stations - 3- 3
Cascade Fast - Fill– Cyclical fueling
patterns
– Public fueling
Fueling Station Fueling Station ComponentsComponents
Gas dryer
Compressor(s)
CNG storage
Dispenser(s)
Fueling Station Fueling Station Components - 2Components - 2
Card reader
Emergency shutdown system
Fire extinguisher
Module 4Module 4Learning ObjectivesLearning Objectives
Know purpose and content of Emergency Action Plan
Be familiar with emergency equipment Understand emergency actions
Purpose of Purpose of Emergency Action PlanEmergency Action Plan
Identification of emergencies
Action items
Notification procedures
Evacuation procedures
Safety systems
Emergency event action items
Facility LayoutFacility Layout
Compressor
CNG storage tanks
Emergency Shutdown Devices (ESDs)
Fire extinguishers
Facility Layout - 2Facility Layout - 2
Pre-planned evacuation route
Designated assembly area(s)
Street address of facility
Safety PracticesSafety Practices
Emergency telephone numbers– Fire department
– Emergency medical help
– Police
–Maintenance
–Adjoining facilities
Safety Signs
Safety Practices – 2Safety Practices – 2
Equipment Inspection:
– Defective equipment• Dispenser hoses• Fueling nozzle and receptacle
– Report unsafe conditions to maintenance technician or station attendant
Safety Practices – 3Safety 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 RulesFire 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 Gas Release at DispenserDispenser
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 CNGFire 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 Fire During Vehicle FuelingVehicle Fueling
Do not attempt to disconnect fueling nozzle from vehicle
Direct others to evacuate immediate area
Press ESD button Call fire department
Combustible Combustible Debris FireDebris 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 5Module 5Learning ObjectivesLearning Objectives
Understand how to correctly operate safety equipment
– Fire extinguisher
– Emergency shut-down device
Correct Use of Correct Use of Safety EquipmentSafety 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 Correct Use of Safety Equipment - 2Safety 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 6Module 6Learning ObjectivesLearning 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 SystemCNG 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 - 2CNG 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 NGVs vs. Gasoline & Diesel VehiclesVehicles
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 1100o F to ignite
– High temperature not usually available
On-Board Fuel Storage On-Board Fuel Storage System 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 On-Board Fuel Storage System - 2System - 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 3,600 psi @ 70o F
Module 7Module 7Learning ObjectivesLearning Objectives
Be familiar with fueling instructions
Understand fueling nozzle/receptacle operation
Fueling InstructionsFueling 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 - 2Fueling 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 - 3Fueling 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