LNG Hazards

LNG Hazards – Introduction Liquefied Natural Gas Facilitates transportation and storage of natural gas 600:1 vapor to liquid ratio Natural gas is refrigerated to cryogenic temperatures to liquefy it Liquefaction and vaporization facilities Natural gas in it’s vaporous form requires large volumes for storage. Liquefying it reduces the volume by a factor of approximately 600 to 1 making it much easier to store and transport over long distances. The liquefaction process involves refrigerating natural gas using natural materials such as ethane and propane as refrigerants. At atmospheric pressure natural gas must be chilled to approximately -260 degrees F to convert it to a liquid form. Once liquefied it is typically stored in low pressure (less than 15 PSI) storage tanks. LNG facilities may consist of a liquefaction plant, a vaporization and distribution plant, or a combination of the two.

LNG Hazards – LNG Properties Mostly methane with small amounts of propane, ethane and other materials Very flammable Flammability range of 5% to 15% Cryogenic at ~ -260 ºF Near atmospheric pressure in most cases Heavier than air below ~ 170 ºF

LNG Hazards – Types of Facilities Liquefaction At source of fuel Converts natural gas to LNG Base Load Main receiving point for large shipments of LNG Vaporization facility Peak Shaving Liquefies natural gas during off season, stores it and vaporizes it during high demand periods Liquefaction and vaporization processes

LNG Hazards – Types of Facilities Distribution Relatively small operation Receives shipments of LNG Normally by tanker truck May supply remote town or specific facility Vehicle Fueling Similar to Distribution facility but for refueling vehicles only

LNG Hazards – Typical Hazards Storage Tank Diked Areas Typically earthen banks Containment in case of tank leak or rupture Very large areas Storage Tank Relief Valves Located on top of storage tanks Fire hazard due to lightning strikes Manual fire fighting not practical Need LNG storage tank diked area picture

LNG Hazards – Typical Hazards Pump Skids and/or Areas May be inside storage tank dike May be in pit outside of dike Potential for large fire due to LNG flow rates Vaporizers Many different type Direct fired Remote heat source Ambient air Water bath

LNG Hazards – Typical Hazards Loading / Unloading Hazards Truck loading/unloading Loading arms for transfer from ship at marine terminals General Plant Areas Process piping Pipe racks Typical plant hazards Need LNG truck loading rack area picture

LNG Hazards – Typical Hazards Enclosed Areas Computer rooms Control rooms Buildings enclosing equipment

LNG Hazards – Protection Objectives Dikes to Control LNG Flow Collection Pits in Safe Location Natural Gas Vapor Control Flame Extinguishment Heat Flux Control Separation Between Hazards Between Hazards and Facilities

LNG Hazards – Detection Methods Flammable Gas Flame Heat Spot detectors Linear detectors Video Need Gas Detector Slide

LNG Hazards – Agents Sprinkler Building sprinkler systems Equipment / piping heat protection Cooling of equipment/piping Will not extinguish natural gas fires Vapor control Prevent downwind drift Warm vapors

LNG Hazards – Agents Water Fog / Spray Vapor control Heat control Warms vapors to prevent downwind travel Heat control Used to control heat flux Protect fire fighters and/or exposures to a fire

LNG Hazards – Agents High Expansion Foam Typically used for diked areas Required containment Vapor control Natural gas vapor forms chimneys that warms vapor Fire control Natural gas vapor forms chimneys that reduces flame size

LNG Hazards – Agents Dry Chemical Extinguishes natural gas fires Portables & hose-lines General plant protection High capacity monitors Specific hazards Fixed nozzle systems Automatic actuation

LNG Hazards – Agents Clean Agents Indoor total flood systems only Computer rooms Control rooms Hazardous enclosures Normally occupied areas