Flammable Cryogenic Liquid Carriers

Flammable Cryogenic Liquid Carriers Thank You to the Seminar Sponsor Saturday, March 19, 2016 Newport County, Rhode Island, USA Seminar Provider and Host Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 1

Agenda & Topics Morning 0830-1230 01 Introduction 02 LNG Properties and Characteristics 03 LNG Hazards 04 LNG Industry overview Afternoon 1330 1630 Interactive Work Shop 05 LNG Fuel Vessel Design and Construction 06 Fuel Tanks and Fuel Supply Systems 07 Gas Atmosphere Control and Monitoring, Venting, Inerting, unique repair hazards Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 2

02 Physical & Chemical Properties Properties and Characteristics of LNG and natural gas Pressure and Temperature, including vapor pressure / temperature relationship Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 3

LNG Properties and Characteristics LNG is natural gas which has been converted to liquid form for ease of transport and storage LNG is composed of mostly methane, with ethane, propane, butane, pentane and other trace liquid gases When liquefied the natural gas volume is reduced by a factor of about 600 to 1 LNG is odorless, colorless, non-corrosive, non-flammable, and non-toxic The properties that make LNG a good source of energy can also make it hazardous if not fully contained Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 4

Interactive Exercise Refer to the LNG Safety Data Sheet: What is the boiling point of LNG? - 162 C (~- 160 C, varies with composition) What is the flashpoint of LNG? -187.8 C What is the specific gravity of LNG? 0.45 t/m3 (varies with composition) What are the flammable limits for LNG? 5%-15% (gas, by volume in air) What is the auto ignition temperature of LNG? 537 C What is the chemical formula for methane? CH4 Based on the SDS, what are the primary hazards? Flammability, cryogenic hazard, asphyxiation Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 5

Composition of LNG Chemical Chemical Formula Low High Methane CH 4 87% 99% Ethane C 2 H 6 <1% 10% Propane C 3 H 8 >1% 5% Butane C 4 H 10 >1% >1% Nitrogen N 2 0.1% 1% Other Hydrocarbons Various Trace Trace Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 7

Cryogenic Liquids Cryogenic fluids are gases that have been liquefied by having their temperature brought below 150 C* Common Cryogens Boiling Points: Ethane, -83.3 C Ethylene, -104 C LNG (methane) -162 C Oxygen, -183 C Argon, -186 C Nitrogen, -196 C Hydrogen, -253 C Helium, -269 C LNG boiling point ~ -160 C (at atmospheric pressure, depending on composition) LNG is one of the warmer cryogens Most materials become brittle at cryogenic temperatures Steel Many plastics Rubber (i.e. gaskets) Skin Suitable materials for LNG service: Stainless Steel Nickel Steel (9% Ni, Invar, etc.) Aluminum All cryogenic liquids are gases at normal temperatures and pressures. (http://www.ccohs.ca/oshanswers/prevention/cryogens.html) Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 8

LNG Characteristics Like all liquid fuels, LNG in it s liquid state is not explosive and cannot burn In order to burn LNG must first be vaporized, mixed with air into the correct proportions and then ignited Vaporized LNG is NOT explosive. The flame speed is very slow (~ 6.4 kmh- the risk of unconfined Vapor Cloud Explosion is low Cold vapor is heavier than air and can form flammable mixtures in low / enclosed spots venting consideration Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 9

Heat of Combustion LNG burns hot, which is why it s such a great fuel Methane 1950 C Natural Gas 1960 C Propane 1980 C Gasoline 2087 C Fuel Oil ( Diesel / IFO / HFO) 2100 C But The radiant heat of an LNG fire is a safety concern of government regulators, fire and safety officials, and the public. Combustion of spilled LNG vapor clouds will involve combustion of heavies (propane, ethane and butane), adding uncertainty to thermal radiation calculations Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 10

LNG Energy Content Energy Content: 1 gal of Diesel = ~139,000 Btu 1 Gal of LNG = ~ 82,000 Btu 1 Diesel Gal Equivalent (DGE) = 1.7 [139,000btu/82,000Btu = 1.7DGE] Energy Density: 1 gal of LNG weighs 3.8 lb 1 gal of diesel weighs 6.9 lb Pound for pound, more energy in LNG: Diesel = ~20,145 Btu/lb LNG = 21,579 Btu / lb Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 11

Conversions and Equivalents 1 cubic meter gas 1 cubic foot gas 1-million Btu 1 therm 1 gigajoule 1 kilowatt hour 1 cubic meter LNG 1 ton LNG The LNG Business is unit-challenged! cubic cubic foot metre gas gas million Btu therm gigajoule kilowatt hour cubic metre of LNG ton of LNG 1 35.3 0.036 0.36 0.038 10.54 0.00171 0.000725 0.0283 1 0.00102 0.0102 0.00108 0.299 0.00005 0.00002 27.8 981 1 10 1.054 292.7 0.048 0.0192 2.78 98.1 0.1 1 0.105448 29.27 0.0048 0.00192 26.3 930 0.95 9.5 1 277.5 0.045 0.018 0.0949 3.3 0.003415 0.03418 0.0036 1 0.000162 0.000065 584 20 631 21.04 210.4 22.19 6,173 1 0.405 1,379 48 690 52 520 54.8 15 222 2.47 1 Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 12

Conversions and Equivalent Units There s an App for that! www.natgas.info, Chart, Air Products, DNV Available for iphone and Android Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 13

Boiling Point The Boiling Point of LNG is about - 160 C (260ºF) Boil-off Heat In-leak LNG continuously warms due to contact with the warmer surrounding environment. Vapor Liquid The continuous boiling process presents challenges in the safe storage and containment of LNG Boiling produces LNG Vapor known as boil-off gas (BOG) Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 14

Boiling Point of LNG Components Common components of LNG boil at widely varying temperatures: Fuel Boiling Point ( o C) Methane (Natural Gas) -161.5 Ethane -89.0 Propane -42.0 IsoButane -11.7 n-butane -1.0 IsoPentane 27.7 n-pentane 36 n-hexane 68 Composition of LNG can change as it boils if vented or consumed, it weathers Components with the lowest boiling points, nitrogen and methane, will evaporate first. Proportion of heavies increases as methane boils off Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 15

Flammable Range Rule 2: Don t let LNG come in contact with Air! The flammable range for Methane in air is approximately 5% to 15% Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 16

Density of LNG The density of LNG falls between 430 kg/m3 and 470 kg/m3 depending upon actual composition. LNG is less than half the density of water; therefore an LNG spill will always float on water. Density of MDO: 890kg/m3 Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 17

Relative Density of Methane Vapor Methane vapor is lighter than air at temperatures above - 100 C This makes CH4 a relatively safe gas to handle as leaks will not create puddles of flammable vapor Operators must beware of the potential for vented gas to be heavier than air initially Significant during LNG fueling, particularly in active port areas 0.656 kg/m3 @ 25 C, 1 atm 0.716 kg/m3 @ 0 C, 1 atm Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 18

Understanding the Gas Laws All gases have 3 quantifiable characteristics: volume, temperature, and pressure, all of which may change The Ideal Gas Law PV = nrt explains the behavior of gases when temperature, pressure and volume are changing Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 19

Volume V LNG Properties and Characteristics Boyle s Law: for a fixed amount of gas at a fixed temperature, the pressure and volume are inversely proportional. pv = constant Pressure increase = Volume decrease Pressure P Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 20

Temperature (T) LNG Fuel Properties and Characteristics Charles s Law says that for a fixed amount of gas at a fixed pressure, the volume is proportional to the temperature. V/T = constant Temperature increase = Volume increase Volume V Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 21

Temperature T LNG Fuel Properties and Characteristics Gay-Lussac s Law says that for a fixed amount of gas at a fixed volume, the pressure is proportional to the temperature. P/T = constant Temperature increase = Pressure increase Pressure P Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 22

Volume / Pressure / Temperature Relationship 1. Fixed amount, fixed temperature: Pressure increase = Volume decrease 2. Fixed amount, fixed pressure: Temperature increase = Volume increase 3. Fixed amount, fixed volume: Temperature increase = Pressure increase LNG About 600X Natural Gas Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 23

Saturated Vapor Pressure (SVP) The pressure exerted by a saturated vapor at a particular temperature Bubbles form and break through the surface to occupy the space above as vapor Some vapor molecules near the surface re-condense to liquid Saturation pressure is the pressure at which the liquid and vapor phase can exist in equilibrium with each other at a given temperature. As the pressure is increased so is the saturation temperature, until the critical point is reached Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 24

Weathering (aka Ageing ): Boil-off process of LNG changes its composition Produces a liquid with a changing heating value and density, altering the value of the LNG Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 27

Critical Temperature and Pressure The temperature above which the substance cannot be liquefied however great the pressure The pressure at which a substance exists in the liquid state at its critical temperature. Equal to the saturation pressure at the critical temperature. It is the pressure required to compress a gas to its liquid state at its critical temperature LNG Critical pressure: 44.7 Bar LNG Critical Temp: -82.5 C -82.5 C (-117 F) 44.7 bar (648 PSI) Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 28

Knowledge Check What are the primary components of LNG? Methane Ethane Propane Butane Nitrogen What is the molecular structure of methane? 1 carbon atom and 4 hydrogen atoms Can the properties of LNG change over time? Yes- boil-off can change composition, heating value and density True or False? LNG burns hotter than conventional fuels False- gasoline, diesel, propane, HFO all burn hotter Define Saturated Vapor Pressure (SVP): Liquid phase and vapor phase are in equilibrium True or False? You need nearly 2 times more LNG fuel to get the same amount of energy in diesel fuel True, LNG / diesel energy equivalent is 1.7x 29 Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 29

References CG OES Policy Letter No. 01-15, GUIDELINES FOR LIQUEFIED NATURAL GAS FUEL TRANSFER OPERATIONS AND TRAINING OF PERSONNEL ON VESSELS USING NATURAL GAS AS FUEL, February 19, 2015 IMO MSC 285(86), Interim Guidelines on Safety for Natural Gas-Fuelled Engine Installations in Ships, 1 June 2009 CG-521 Policy Letter -1-12 DESIGN CRITERIA FOR NATURAL GAS SYSTEMS, April 19, 2012 IMO STCW.7 Circ 23, Interim Guidance on training for seafarers on board ships using gases or other low-flashpoint fuels HTW 1/17 Development of the International Code of Safety for Ships Using Gases or Low- Flashpoint Fuels (IGF Code) IMO CCC 1/13/Add.1., Annex 4, DRAFT INTERNATIONAL CODE OF SAFETY FOR SHIPS USING GASES OR OTHER LOW-FLASHPOINT FUELS (IGF CODE) ISO TS 18683 Jan 2015, Guidelines for systems and installations for supply of LNG as fuel to ships Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 31

References (continued) ISGOTT 5th Edition SIGTTO Liquefied Gas Handling Principles on Ships and in Terminals, 3 rd Edition 2000 SIGTTO LNG Drip Trays Guidance SIGTTO Guidance for the Prevention of Rollover in LNG Ships Contents SIGTTO LNG Transfer Arms and Manifold Draining, Purging and Disconnection Procedure SIGTTO Use of Insulation Flanges (and Electrically Discontinuous Hoses) at the Ship/Shore and Ship/Ship Interface ABS Guide for PROPULSION AND AUXILIARY SYSTEMS FOR GAS FUELED SHIPS (May 2011, updated February 2014) ABS Bunkering of Liquefied Natural Gas-fueled Marine Vessels in North America 2ND EDITION Copyright 2016 United States Maritime Resource Center, Inc. All Rights Reserved. 32