City Of La Training 4

Presented by: Gil Garcia

Clean Air Power, Inc.

LEV Products Dual-Fuel Training Course Part 4 October 17, 2008

Natural Gas (LNG) Storage & Safe Handling

Glossary



LNG – Liquefied Natural Gas CNG – Compressed Natural Gas NG – Natural Gas D-F – Dual-FuelTM (NG & Diesel) PSI – Pressure absolute PSIG – Pressure gauge CH4 – Methane



FMM – Fuel Management Module

     

Safety 

Truck 

General Practices • Report all leaks or failures • No smoking



Maintenance Facility 

General Practices • Inspect vehicles prior to bringing in the facility • Never leave overnight or unattended for long time • Run vent line from relief vent to outside the shop

LNG 

General Properties 

Mostly Methane 94-99% • Small amounts of Ethane, Propane, Pentane, CO, Nitrogen & CO2



Cryogenic Liquid -259°F @ 0 psi (-190°F @ 105

psi) 

Density 3.5 lb/gal @ 0 psi (3.01 lb/gal @ 105

psi)     

1.68 Gallons LNG = 1 Gallon of Diesel LHV 75,000 Btu/gal 130 Octane 5% - 15% Flammability Range 1000° F Ignition Temp

LNG 

Health Hazards   

Cryogenic Asphyxiation Flammable Vapor

LNG  Health

Hazards

 Vapor

Cloud not a leak

LNG  Protective  Goggles

Equipment

/ Face Shield

 Apron  Gloves

– Easily Removable  Long Sleeves  Long Pants

LNG 

First Aid 

Cryogenic Burns • Restore affected body part to normal temperature (warm water bath 100°F - 110°F) • Once thawed cover the area with dry sterile dressing • Seek follow-up medical care

LNG  Fire

Safety

 Smoking

prohibited in or around NG fuel stations and vehicles  No open flames or sparks  NG is lighter than air and will rise from the location of a leak  Properly used halon and CO2 fire extinguishers can effectively starve a small NG fire for oxygen  The actual liquid in an LNG fire does not burn, only the gases released from the boiling liquid will burn  Methane detection system operational  LNG vapor vented to a vent stack  Explosion proof electrical wiring / conduit  Dispensing hose break-away fuel nozzle / coupler

LNG Safety LNG is extremely cold, -259oF and boils at atmospheric pressure • Large amounts of natural gas vapor will form from very small amounts of LNG causing pressures to rapidly increase (expansion rate of 620:1) • Natural gas is an asphyxiant •

Natural Gas Safety  Safe 

because . . . Very high ignition temperature

 Very

Autoignition Temperature (degrees F) 1000 800 600 400 200 0

793

999 867 919

Eth e an ol Me th an ol Pr op an Na e tu ral Ga s

Ga s

oli n

#2

480 495

el es Di

small range of flammability (5-15%)  Lighter than air

LNG  LNG

Fuel System Components

 Vehicle

Tank

• Fuel Receptacle • Fill Check Valve • Economizer • Excess Flow Valve • Relief Valves – Primary, Secondary • PSI Gauge • Liquid Level Gauge • Heat Exchanger • Vent Stack

LNG 

LNG Fuel System Components

LNG LNG Fuel Systems Components, Cont.  FMM

• Regulator • Filter .01 Micron

 Fuel

Lines

• SS Hard Lines • SS Flex Lines • SS Fittings • Brass Fittings

 Secondary

Filter

LNG FMM

-10 JIC flared fittings

• Regulator • Filter .01 Micron Filter Housing

LNG Regulator

Methane Detectors Vehicle

• Amerex – AMGADS III Handheld

• TIF • Bacharach • UEI • Inspect IT 1st My

Favorite

• Soapy water

Onboard Methane Detectors Amerex - AMGaDS III

Plus

Onboard Detectors  Detection

sensors are typically placed in passenger and engine compartment in various locations

Onboard Methane Detectors Cab Mounted Detector

Engine Compartment Detector

Handheld Methane Detectors

Tif

- 8800A

Methods of Detection Handheld:  Run

the wand over all joints, fittings and connections to expose leaks with audible tones and LEDs

Handheld Methane Detectors

 Spray •

bottle

Snoop

Methods of Detection Spray bottle:  With

Snoop solution spray over all joints, fittings and connections to expose the slightest leak with tiny bubbles too large bubbles with larger leaks.

BNC Connector Leak

Elbow Leak

LNG Tank Information and Diagnostics

Internal LNG System

External LNG System

Tank Safety Features 

Dual wall stainless tank construction



Redundant safety pressure relief valves with independent flow paths



Excess flow valve on liquid use line



Dual check valves on fill line



Economizer regulator valve



Protective handling ring or shroud



Non-flammable Super insulation

Tank Components •

Lines

•

Hand Valves

•

Check Valve

•

Relief Valves

•

Economizer

Fuel Sender Fill

Lines

230 PSI Vent

BNC Fitting Excess Flow Valve

350 PSI

•

Fittings

•

Excess Flow Valve

Hand Valves

Super-Insulation  NexGen

tanks are built as a tank within a tank similar to a thermos bottle.

 The

space in-between the two tanks (the annular space) is superinsulated.

LNG Tank Insulation Insulation Information Home LNG Vehicle Heating Tank Insulation Insulation Insulation 1-2 feet Thickness R-value

19-30

1 inch +vacuum 8,500

LNG Tank Efficiency Thermos bottle containing iced tea

LNG stored in vehicle tank

Stored Liquid Temperature

40 degrees

-210 degrees

Ambient Temperature

100 degrees

100 degrees

Temperature Differential

60 degrees

310 degrees

Less than 12 hours

7-10 days

Useful Holding Time

Regulation Of Pressure  The

economizer regulates tank pressure whenever liquid is being used from tank.  Redundant relief valves regulate tank pressure all of the time-whether or not liquid is being used.  The final line regulator regulates overpressurization of fuel going to engine whenever LNG is being used.  Pressure can also be manually lowered

Tank Fill Circuit  Top

fill design allows cold liquid to collapse head pressure by condensing the warmer vapor which allows the tank to be filled without venting.

Liquid Use Circuit  When

tank pressure is below that of the economizer set pressure, only liquid will be used.

 Internal

liquid naturally boils as the pressure decreases to insure tank does not run out of pressure.

Economizer Regulator  Regulates

tank

pressure  Pulls vapor from the upper portion of the tank to mix in with the liquid being used by the engine thereby lowering the pressure within the tank until the setpoint of the economizer is reached,

Economizer Circuit  When

tank pressure is above the set point of the economizer, the economizer opens and allows vapor to mix in with the liquid to assist in lowering the tank pressure.

Heat Exchanger

Final Line Regulator  Used

to keep pressure below the maximum level required by the engine.

 The

economizer regulator at the tank is used to regulate pressure of the system.

Fuel Gauge Components •

Sensor wire inside tank

•

Sender unit (black box)

•

Gauge

•

Coaxial cable and connections

•

Electrical wiring

Problem Symptoms •

Fuel gauge inoperative or inaccurate • • •

Check capacitance at BNC connector Replace sender with known good unit Check 12 VDC power to gauge

Gauge Tester

Problem Symptoms •

Low pressure or low fuel level • •

•

Lacks power Kicks out of mode (fault 23 or 25)

High pressure • • •

Hard to fuel Excess frosting or sweating System is venting

Problem Symptoms •

Too cold of fuel • •

•

Poor driveability Kick out of mode

Leaks • • • •

Methane detection system warning Periodic leak checks Poor driveability Poor fuel mileage

Preliminary Checks •

Visual inspection

•

Leak check

•

Hand valves

•

Relief valves

•

Electrical connections

System Leaks 

Frost or bubbling around leak area



Soap bubble solution such as snoop



Portable methane detector



On-board methane detection system



Poor fuel mileage

Can’t Fuel Without Venting (may be normal operation under certain Conditions)

Has vehicle sat for a period of time? • Normal heat leak  Is there any other reason that pressure is high? • New tank = ”Hot Tank”. • Excess heat will cause excess pressure rise.  Check fuel station filling operation and procedure (Contact station manager) 

Excess Frosting/Sweating 

Some frosting and sweating is normal, especially near the plumbing end of the tank.



If frosting and sweating are occurring along the sides and the other end, the tank may have a possible vacuum/ insulation problem, requiring a vacuum integrity test.

Excess Frosting  Not

OK -Frosting

Excess Sweating  Not

OK -Sweating

System is Venting

System is Venting May be a normal situation if vehicle has sat for awhile (several days or more)  Economizer may not be opening to economize fuel.  Normal pressure but faulty pressure relief valves.  Excess pressure buildup due to soft or no vacuum within the annular space. 

Diagnosis And Repair Leaks  Pressure problems 

• •

Too high Too low

Too cold of fuel  Fuel gauge diagnosis 

Leak Repair •

Compression Fittings

• Hand Valves

•

Pipe Threaded Fittings

• Economizer

•

BNC Nipple/Elbow

•

Relief Valves

• Final Line Regulator • Weld Leak

System Leaks

BNC Connector Leak

Leak Repair Procedures Follow LNG safety measures  Always make sure leaking line, tank, component and/or fitting are not under pressure and do not contain LNG before disassembly  Leaking fittings should be warmed up before repair  Do not use teflon thread tape  Always use 2 wrenches on fittings 

Compression Fitting Leaks  Don’t

use thread sealant on compression fittings  Check fitting for looseness/tighten as necessary  If leak persists, disassemble fitting, inspect and replace or repair as necessary • • • •

Check and clean any debris off of fitting Check for cross-threaded threads Inspect ferrule to make sure Inspect for taper cracksis straight and not grooved or damaged

Pipe Threaded Fitting Leaks  Disassemble

fitting  Clean and inspect fittings • • •

Check for fitting distortion Check for cross-threaded threads Inspect for cracks

 Replace

any damaged components  Use proper sealant sparingly  Always use 2 wrenches, reassemble fitting and tighten to correct location without backing up wrenches

BNC Nipple/Elbow Leaks Use same procedure as pipethreaded fittings  BNC nipple connector pulls off of pin terminal  Terminal will have to be removed from wire to replace the BNC elbow  During reassembly, make sure terminal is plugged onto BNC nipple correctly 

Relief Valve Leaks 

Determine where relief valve is leaking



If leaking at the external end, look at pressure on tank while relief valve is leaking to determine whether it is good or bad



If leaking from the pipe threaded end, use pipe threaded procedure when repairing leak



Weep hole must point downward to assist in draining moisture

Hand Valve Leaks  If

valve is leaking past stem seal, try tightening #25 otherwise install the valve repair kit  If valve is leaking past the seat, install valve repair kit, which includes all of the numbered parts

Economizer Leaks  If

the economizer is leaking from any of the fittings, repair by using the pipe thread procedure.

 If

the economizer is leaking where the lower half connects onto the upper half, then tighten the lower part onto the upper.

Final Line Regulator Leaks  If

the fittings on the final line regulator leak, then follow the pipe threaded procedures  If the leak is occurring from between the lower and upper halves, then tighten down the screws that hold the two halves together.  If regulator still leaks, then

Welding Leaks  Do

not weld onto vacuum jacketed tanks or lines. Special procedures are required to assure that a hole is not created.

 If

a weld leak is found, the tank will have to be removed and sent back to Chart for repair.

Pressure Problem Diagnosis

Tank Pressure  If

tank pressure is low, then; • The tank(s) are empty • There is a leak in the system • The fuel is too cold (fueling, overeconomizing)  If tank pressure is high, then; • Normal situation • Ineffective economizer circuit • “Hot” tank • Insulation problem (excess heat leak)

System Pressure 

When the engine has been run under load, the final line pressure is normally between 105 and 120 PSI.

If the final line pressure is; 

Over 130 PSI, adjust or replace the final line regulator as necessary.



Below 105 PSI, perform “low” tank pressure diagnosis.



Below 105 PSI and below the actual tank pressure, make sure the liquid use valve is completely open, check final line regulator adjustment, possible fuel contamination and for possible obstruction.

Diagnosing Excess Pressure Note pressure at tank.  Has vehicle been driven during the last 24 hours?  Run vehicle for 1 hour and note pressure again. Is economizer U-tube frosted up and has the pressure fallen?  Perform Vacuum Integrity Test 

Vacuum Integrity Test 

Perform leak check.



Fill the tank and drive the vehicle until 3/4 to 1/2 of a tank of fuel remains.



Shut off the vehicle and wait for 30 minutes.



For multiple tank vehicles, isolate tanks from each other by removing and capping off the fill line connection on each tank.

Vacuum Integrity Test 

Close the liquid and vent valves off and note the tank pressure(s).



Let the vehicle sit for 12 hours without being run at all and then note the pressure again.



If pressure rise is over 40 PSI in 24 hours, remove tank and send out for repair.

Too Low of Pressure (at the tank) •

Economizer-stuck open or miscalibrated

•

Saturation pressure too low •

Fuel station saturation pressure too low

•

Fuel is desaturating • Leak • Multiple tank vents tied together

Too Cold of Fuel at Engine •

Poor heat exchanger performance • Low

coolant flow

• Air

bubble within heat exchanger

• Too

high of coolant flow

Fuel Gauge Diagnosis •

Blown fuse

•

Miswired

•

Connections •

Loose

•

Corroded

•

Water contamination

• Broken sender wire within tank • Sender unit (black box) • Water contamination • Miscalibrated for system

Fuel Gauge Diagnosis  Fuel

gauge troubleshooting kit part number 10989254 includes: • • •

Capacitance meter Weatherpac voltage tap BNC test lead

 Follow

procedure in LNG Vehicle Fuel Tank System Operations Manual starting on page 14.

Fuel Management Module “FMM”  Keeps

the flow of NG to the engine at its optimum pressure and filters the NG  The economizer at the tank is used to regulate the pressure of the system

Where to Get More Information  Colleges:  American

River College – Sacramento  Cerritos Community College – Norwalk  College of the Desert – Palm Desert  Cuyamaca College – El Cajon  Long Beach City College – Long Beach  San Diego Miramar College - SD  National Alternative Fuels Training Program – WVU Morgantown, WV  National Automotive Technicians Education Foundation – ASE certifications

Publications 

NFPA National Fire Protection Association NFPA 57 Standard for Liquefied Natural Gas (LNG) Vehicular Fuel Systems  NFPA 59A Standard for Liquefied Natural Gas (LNG) Storage and Handling 

Web Sites  www.cleanairpartners.com  www.cat.com  www.catpower.com  www.naturalfuels.com  www.sae.org  www.ccities.doe.gov  www.afdc.doe.gov  www.ngvc.org  www.energy.ca.gov  www.arb.ca.gov  www.aqmd.gov

Presented by: Gil Garcia

Clean Air Power, Inc.

LEV Products

Dual-Fuel Training Course Part 4 October 17, 2008