LIQUEFIED GASES Marine Transportation and Storage Alain Vaudolon WITHERBY Witherby Seamanship International A Division of Witherby Publishing Group Ltd 4 Dunlop Square, Livingston, Edinburgh, EH54 8SB, Scotland, UK Tel No: +44(0)1506 463 227 - Fax No: +44(0)1506 468 999 Email: info@emailws.com - Web: www.witherbyseamanship.com First Published 2000 Reprinted 2010 ISBN 1 85609 197 8 eBook ISBN 978 1 85609 539 6 © Alain Vaudolon British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Notice of Terms of Use All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher and copyright owner. While the principles discussed and the details given in this book (Liquefied Gases: Marine Transportation and Storage) are the product of careful study, the author and the publisher cannot in any way guarantee the suitability of recommendations made in this book for individual problems, and they shall not be under any legal liability of any kind in respect of or arising out of the form or contents of this book or any error therein, or in the reliance of any person thereon. Printed and bound in Great Britain by Bell & Bain Ltd, Glasgow Published by Witherby Publishing Group Ltd 4 Dunlop Square, Livingston, Edinburgh, EH54 8SB, Scotland, UK Tel No: +44(0)1506 463 227 Fax No: +44(0)1506 468 999 Email: info@emailws.com Web: www.witherbys.com W ITHERBY P U BLISHING GRO U PSince-1740 iii This book would not have been written without the help of the many friends and colleagues with whom I had the honour and pleasure to work during all those years spent running after liquefied gas tankers. I am grateful to Mr Claude Detourne, Senior Vice-President, Gaz de France and President, International Gas Union, for putting his name to the Foreword. I extend special thanks to Chris Clucas, Consultant, Dorchester Marine, who took the trouble to read the complete draft and suggest many valuable improvements; Richard Eddy, Consultant, Osprey Maritime and Jean Marie Poitou, Consultant, Gas-Team who did the same with various sections and Roger Roue, Technical Adviser, SIGTTO, who let me choose photographs from the large library he is setting up. Dave Cullen, Vice President, Ebara Cryodynamics, Andre Raymond, Sales Director, Foxboro, ACKNOWLEDGEMENTS Jacques Delhemes, President, Gaz Transport & Technigaz, Yoshitoh Okumura, General Manager, Ishikawajima Harima Heavy Industries, Yoshiaki Tamura, General Manager, The Kansai Electric Corporation, Alain Dorange, Managing Director, KSB-AMRI, Captain Shahib Sabeh, Marine Superintendent, Malaysia LNG, all provided photographs of the products they represent. A special mention of my late and sadly missed friend Captain Jean Trevedy who provided some of the stories in Chapter 12. I must certainly not omit the help received from my daughter Sophie in solving some tricky computer graphic problems and from my wife Theresa who was brave enough to read the full draft and correct my occasional franglais and numerous spelling errors. Alain Vaudolon July 2000 v FOREWORD by Monsieur Claude Detourne Inspecteur General Du Gaz De France President – International Gas Union Gas can be transported in two ways. In gaseous form, under high pressure through large pipelines, or in liquefied form, by ship. The pipeline option is extensively used but it is only viable under certain conditions; parameters such as the quantity to be transported, the distance over which it has to be transported, the depth of water to be crossed and the amount of required initial investment limit its application. Transportation by ship is usually flexible enough to accommodate the fluctuations of the market, reliable enough to satisfy long-term users and economical enough for the gas to compete successfully against other products. The opportunity was there to create and develop a new industry, derived from traditional shipping but with very specific requirements. It involved not only the ships at sea but also the production and storage units ashore. As soon as the means became available, the growth of the transport of petroleum and chemical gases was quite spectacular and yet, this was nothing compared to what has happened with the development of LNG. This book reviews the history of the marine transportation of liquefied gases and the conditions which are prevailing today. It was not intended to go into explicit technical detail but to try to give an overview of all the aspects of the industry, covering the characteristics of the ships, the rules and regulations in force, details of storage tanks on shore and a look at safety and reliability. It should provide valuable general information to all those who are involved in the marine transportation of liquefied gases, including ship and terminal operators, ships agents, port authorities, charterers, cargo traders, insurance brokers and underwriters. The book reflects the author’s accumulated experience during his distinguished career in gas shipping. The known world reserves of gas are larger than those of oil and yet, for a long time, this gas did not attract much interest. On the contrary, it was considered a hindrance by those involved in the recovery of oil. For many years, the associated gas was flared and the dry wells containing natural gas were ignored. At the beginning of the century, when the first attemps at industrial production of gas were made, it was recognised that gas had the potential to change the world’s way of living. LPG, by providing bottled gas, has transformed the way millions of people heat their homes and cook. Development of chemical gases has brought tremendous changes to people’s lives by providing them with all sorts of cheap plastic objects, tyres for their cars, fertilisers for growing their crops. The development of natural gas has made available a clean source of energy, replacing old town gas, and providing a competitive and clean alternative for industrial use and the production of electricity. Gas, however, like oil and coal, needs to be transported from the production sites, usually located in sparsely populated areas, to where it is needed. The transportation of oil and coal was straightforward and could be very quickly developed on a large scale. The transportation of gas, however, presented a number of technological problems which demanded a little more attention. Gas can be used at the point of production, but there is not usually much demand. In recent years, large refineries, producing valuable chemicals, have been developed in gas-producing countries, but this only uses a fraction of the available quantity. vi 1. Mast to be Installed in a Gaz Transport Membrane Type Tank. vii Page Acknowledgements iii Foreword v The Author xiii References xv List of Illustrations xvii Charts and Drawings xx Definitions xxiii Chapter 1 Introduction 1 Chapter 2 The Products 5 2.1 LIQUEFIED PETROLEUM GAS (LPG) - ORIGINS AND CHARACTERISTICS 5 2.2 LIQUEFIED NATURAL GAS (LNG) – ORIGIN AND CHARACTERISTICS 7 2.3 LIQUEFIED PETROCHEMICAL GASES 10 2.3.1 General 10 2.3.2 Ammonia (NH3) 10 2.3.3 Butadiene (C4H6) 11 2.3.4 Propylene (C3H6) 11 2.3.5 Vinyl Chloride Monomer (VCM) (C2H3CL) 12 2.3.6 Ethylene (C2H4) 13 Chapter 3 History 15 3.1 LIQUEFIED PETROLEUM GAS (LPG) 15 3.1.1 The Beginning 15 3.1.2 Development 19 3.1.3 Liquefied Petrochemical Gases 20 3.1.4 Ethylene Tankers 21 3.2 LIQUEFIED NATURAL GAS (LNG) 21 3.2.1 The Beginning 21 3.2.2 Development 27 CONTENTS Liquefied Gases: Marine Transportation and Storage viii Chapter 4 The International Trade 31 4.1 LIQUEFIED PETROLEUM AND PETROCHEMICAL GASES 31 4.1.1 The Fleet 31 4.1.2 The Trade 35 a) General 35 b) Liquefied Petroleum Gas (LPG) 35 c) Ammonia 37 d) Petrochemical Gases 37 i) Ethylene 37 ii) Propylene 39 iii) Butadiene 39 iv) Vinyl Chloride Monomer (VCM) 39 4.1.3 The Terminals 40 4.1.4 Commercial Titles 40 4.2 LIQUEFIED NATURAL GAS (LNG) 42 4.2.1 The Fleet 42 4.2.2 The Trade 44 4.2.3 The Terminals 46 4.2.4 Commercial Titles 48 Chapter 5 Various Types of Liquefied Gas Tankers 53 5.1 GENERAL – THE IMO CODE DEFINITIONS 53 5.2 FULLY PRESSURISED SHIPS 56 5.3 SEMI-PRESSURISED SHIPS 57 5.4 FULLY REFRIGERATED SHIPS 59 5.5 INSULATED SHIPS FOR LNG 61 5.5.1 Spherical Tanks 65 5.5.2 Membrane Tanks 66 5.5.3 Self-Supporting Prismatic Type B (SPB) Tanks 69 Chapter 6 Other Characteristics Specific to Liquefied Gas Tankers 71 6.1 GENERAL 71 6.2 RULES AND REGULATIONS 71 6.2.1 Design and Construction 71 6.2.2 Operation and Crewing 73 6.3 CARGO EQUIPMENT 74 ix Contents 6.3.1 Pipes and Valves 74 6.3.2 Reliquefaction Plants 76 6.3.3 Pumps and Compressors 78 6.3.4 Cargo Quantity Measurement - Custody Transfer 81 6.3.5 Inert Gas and Nitrogen 81 6.4 SAFETY EQUIPMENT 84 6.4.1 Emergency Shut-Down Systems (ESDS) 84 6.4.2 Other Safety Equipment 86 Chapter 7 Ports, Terminals and Jetties 87 7.1 REDUCING THE LEVEL OF RISKS 87 7.2 LOCATION, DESIGN AND CONSTRUCTION 88 7.3 OPERATIONAL PROCEDURES 90 Chapter 8 Shore Storage Tanks 95 8.1 GENERAL 95 8.2 STORAGE UNDER PRESSURE AT AMBIENT TEMPERATURE 95 8.2.1 Spherical and Horizontal Cylindrical Tanks Above Ground 95 8.2.2 Mounded Horizontal Cylindrical Tanks 96 8.2.3 Underground Caverns 97 8.3 STORAGE IN SEMI-PRESSURISED SPHERES 97 8.4 STORAGE AT ATMOSPHERIC PRESSURE IN REFRIGERATED CONDITION 98 8.4.1 Different Types of Refrigerated Storage Tanks 98 a) Above-Ground Tanks 98 b) In-Ground Tanks 98 c) In-Pit or Semi-Buried Tanks 100 8.4.2 Different Types of Containment Systems 101 a) Single Containment 101 b) Double Containment 102 c) Full Containment 103 d) Membrane Tanks 103 8.4.3 Standard for Low Temperature Cylindrical Vertical Storage Tanks 104 8.4.4 Materials Used for Low Temperature Storage Tanks 105 8.5 EVOLUTION OF THE SIZE OF SHORE STORAGE TANKS 105 Liquefied Gases: Marine Transportation and Storage x 8.6 SOME POSSIBLE INCIDENTS IN LIQUEFIED GAS SHORE STORAGE TANKS 107 8.6.1 Rollover 107 8.6.2 Fire Hazard 107 8.6.3 Boiling Liquid Expanding Vapour Explosion (BLEVE) 108 Chapter 9 Operations 111 9.1 SHIP OPERATIONS 111 9.1.1 General 111 9.1.2 Cargo Operations 111 a) Preparation for loading 112 b) Loading 115 c) Loaded Voyage 119 d) Discharging 120 e) Ballast Voyage 121 f) Changing Cargo or Preparation for Dry docking 122 g) Changing Cargo after Ammonia. 123 9.2 PORT OPERATIONS 123 9.2.1 General 123 9.2.2 Exchange of Information Between Ship, Port and Terminal 124 9.2.3 Ship’s Arrival and Transit to the Berth 124 9.2.4 Ship Alongside the Berth 125 9.2.5 Safety and Contingency 126 Chapter 10 Ship-to-Ship Transfer 129 10.1 LPG AND PETROCHEMICAL GASES 129 10.2 LNG 131 Chapter 11 Safety Liquefied Gas of Marine Transportation 133 11.1 SAFETY RECORD 133 11.2 HAZARDS AND RISKS 134 11.2.1 Introduction 134 11.2.2 Hazard Identification 135 11.2.3 Consequences of Certain Types of Accident 136 11.2.4 Frequency of Accident Scenarios 139 a) General 139 b) Frequency of Ship Incidents 139 xi Contents c) Frequency of Terminal Incidents 140 d) Other Hazards 140 e) Ignition of Releases 140 11.2.5 RISK ASSESSMENT 141 Chapter 12 Some Stories!... 143 12.1 ACCIDENTS INVOLVING LNG AND LPG STORAGE TANKS 143 12.1.1 The Cleveland, Ohio LNG Tank Failure – October 1944 143 12.1.2 Feyzin Refinery and Storage Facilities – France – 1966 144 12.1.3 LPG Storage and Distribution Centre in Mexico City – November 1984 145 12.2 TWO ACCIDENTS INVOLVING LNG TANKERS 147 12.2.1 The El Paso Paul Kaiser – July 1979 147 12.2.2 LNG Taurus – 1979 150 12.3 ACCIDENTS INVOLVING LPG TANKERS 150 12.3.1 The Yuyo Maru Collision – November 1974 150 12.3.2 The Gas Fountain – Iraq/Iran War – October 1984 151 12.4 SOME OTHER INCIDENTS FROM MY OWN RECORDS 153 12.4.1 A Bad Night in Zvetina – Libya 153 12.4.2 A Few Quiet Days Off the Mexican West Coast 155 12.4.3 An Example of Brittle Fracture! 156 12.4.4 A Call to Beirut, Lebanon, in March 1976, to Discharge a Part–Cargo of LPG 156 12.4.5 An Attempt at Jettisoning LNG 158 Conclusion 165 Index 167 53 The most recent challenge was the need to transport LNG with a minimum temperature of -162°C, a critical pressure of 82 bar, which precluded any possibility of pressurised or semi- pressurised tanks, and no practical on board means of reliquefaction. The inventiveness of the designers was fully demonstrated by the number of different tank designs to come off the drawing boards. This was the situation at the end of the 1960’s. The liquefied gas tanker fleet was composed of a large number of small pressurised ships, a few semi-pressurised and fully refrigerated ships and some LNG tankers. The safety of the transport of liquefied gas by sea had always raised some concern. Although the general safety record of the fleet was good, a few isolated incidents were attracting public attention. These were due, amongst other causes, to the dubious stability of some of the small pressurised ships and to the practice of carrying liquid petroleum products in the side tanks of fully refrigerated ships. This was the cause of the disastrous fire on board the YoyoMaru in the Tokyo Bay in 1974. In 1968, the Inter-Governmental Maritime Consultative Organization (IMCO), as it was known at the time, now the International Maritime Organization (IMO), started, a programme to develop standards for vessels carrying hazardous 5.1 GENERAL – THE IMO CODE DEFINITIONS The evolution of liquefied gas tankers over the years has been broadly determined by the different types of product to be transported, their physical condition at the loading and discharging ports and the improvement of technology. We have seen that the first ships were designed to transport small quantities of butane and propane at ambient temperature. The maximum pressure of propane at +45°C* is 16 bar gauge and this decided the maximum pressure for which the tanks had to be designed. Very soon, ammonia was added to the list of products to be transported and the maximum pressure to be considered for the design of the cargo tanks was increased to 18 bar gauge, as this is the maximum pressure of ammonia at +45°C*. The technology and materials available for the construction of the tanks at that time only allowed fairly small units. The weight of the tanks was a further limitation on ship size. Demand for the transport of larger volumes of cargo and development of improved reliquefaction and metallurgical technology allowed the construction of tanks with lower maximum design pressures and lower minimum temperatures, e.g. progression to semi-pressurised and fully refrigerated ships and ethylene tankers. Chapter 5 VARIOUS TYPES OF LIQUEFIED GAS TANKERS * +45°C is considered the maximum temperature that a cargo is likely to reach during any sea-going voyage. On pressurised ships without a refrigeration system, a network of water pipes with spray nozzles is arranged over the tank tops to cool the tanks if the temperature is likely to rise above this limit. Liquefied Gases: Marine Transportation and Storage 54 the definition of a liquefied gas, were included because they are commonly transported in gas ships. A revised edition of the GC Code was published in 1993. This edition includes the four sets of amendments introduced since 1975, and converts all measurement units to the SI system. This new edition is called The IMO International Code for the Construction and Equipment of Ships Carrying Liquefied Gas in Bulk or IGC Code. [3] The main thrust of the IGC Code is to focus attention on the design of the cargo containment systems, piping systems, pressure vessels, construction materials, ship survival capability and cargo tank locations in order to minimise the release of cargo in the event of a casualty. These were the areas for which specific details and requirements were most needed. The IGC Code also recognises that, in order to ensure the safe transport of liquefied gases, the total system must be appraised, including other equally important aspects such as operations, traffic control and handling in port. The IGC Code contains detailed requirements governing the complete design and fitting-out of new ships. Following the application of the GC Code, the various designs of liquefied gas carriers were confirmed as they are known today. The GC Code defined various types of cargo containment systems, which can be summarised as follows: • Integral tanks, form a structural part of the ship’s hull and are influenced in the same manner and by the same loads which stress the adjacent hull structure. • Membrane tanks, non-self supporting tanks which consist of a thin layer (membrane) supported through insulation by the adjacent hull structure. The membrane is designed in such a way that thermal materials in bulk. The Code for the Construction of Ships Carrying Dangerous Chemicals in Bulk was completed in 1971 and adopted as Resolution A.212(VII). The programme was continued and, in November 1975, the Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (GC Code) was adopted by the Ninth Assembly of the IMCO as Resolution A.328(IX). The Resolution recommended that all member Governments incorporate its contents into national regulations as soon as possible. The purpose of the GC Code is to provide internationally agreed standards of design, construction and operation for the safe carriage of liquefied gas in bulk. The GC Code was intended to apply only to new ships and it defined the details of its application. Basically, all ships ordered after October 1976 or delivered after June 1980 had to comply fully with the Code. The situation of Existing Ships, those delivered prior to 1976/1980 period, was covered by a separate Code for Existing Ships and the IMCO Assembly, in Resolution A.329 (IX), recommended that ships delivered between those two dates be built, so far as reasonable and practicable, according to the Code for new ships. The GC Code was supported by all major countries involved in liquefied gas shipping and by all major classification societies and it was adopted very quickly as the only acceptable standard for the design, construction and operation of liquefied gas tankers. The GC Code regulates the transport of 27 liquefied gases and certain other substances. It defines a liquefied gas as a product having a vapour pressure of 2.8 bar absolute at a temperature of 37.8°C. A few other chemical products such as chlorine or ethylene oxide, which nearly meet 55 Various Types of Liquefied Gas Tankers 0 Independent tanks type A whose primary design follows classic classification society structural analysis procedures. 0 Independent tanks type B which are designed using model tests, refined analytical tools and analysis methods to determine stress levels, fatigue life, and crack propagation characteristics. 0 Independent tanks type C (also referred to as pressure tanks) which meet pressure vessel criteria where the dominant stress producing load is the service vapour pressure. and other expansion or contraction is accommodated without unduly stressing the membrane. This category of tank includes the internal insulation systems. • Semi-membrane tanks, self-supporting when empty; when loaded, the top, bottom and sides must be supported by the adjacent hull structure. • Independent tanks, self-supporting, these do not form part of the ship’s hull and are not essential for hull strength. Three categories of independent tanks are considered: 36. LNG Tanker of the Gaz Transport Membrane Type. (The Author.)