LNG Operational Practice - Second Edition

This book is written for LNG Officers who require a better understanding of the mechanics and processes involved in operating a modern LNG carrier. The book is laid out with clear diagrams, checklists, guidance and instructions for each of the operations undertaken at each stage of a typical trading cycle for an LNG carrier including: post dry dock, drying of cargo tanks, inerting of cargo tanks, gassing-up the cargo tanks, initial cooldown of cargo tanks, cargo loading, laden voyage, cargo discharge, ballast voyage, ship to ship transfer and preparations for dry dock including warming-up of cargo tanks, inerting of cargo tanks and aeration of cargo tanks.

Preface

Acknowledgements

Section 1: General Information

1 Physical Properties, Composition and Characteristics of LNG

1.1 Overview

1.2 Flammability of LNG

1.3 Saturated Vapour Pressure (SVP)

1.4 Vapour Density

1.5 Safety Precautions in LNG Handling

2 Normal Trading Cycle of an LNGC

3 Cargo Containment Systems

3.1 Overview

3.2 Moss Rosenberg (Moss)

3.3 Mark III (GTT

3.4 NO96 (GTT)

4 Cargo Handling Equipment

4.1 Cargo Pump

4.2 Spray/Stripping Pump

4.3 High Duty Compressor

4.4 Low Duty Compressor

4.5 Gas Heater

4.6 Vaporiser

4.7 Reliquefaction Plant

4.8 Gas Combustion Unit (GCU)

5 Auxiliary Equipment

5.1 The Cargo Valves Remote Control System

5.2 Ship/Shore Link and ESD System

5.3 N2 Generator

5.4 IG Plant

5.5 Custody Transfer and Measurement System (CTMS)

5.6 Cargo Tank Gauging System

5.7 Gas Detection Equipment

5.8 Cofferdam Heating System

5.9 Vacuum Pumps

5.10 Tank Overflow Protection

Section 2: Post Dry-dock Operations

6 Operations Related to Auxiliary Systems

6.1 Moss Type LNG Carriers

6.2 Membrane Type LNG Carriers (Mark III and NO96)

7 Cargo Tank Operations

7.1 Drying of Cargo Tanks

7.2 Inerting of Cargo Tanks

7.3 Gassing-up the Cargo Tanks

7.4 Initial Cooldown of Cargo Tanks

Section 3: In-service Operations

8 Loading Operations

8.1 Overview

8.2 Preparation for Loading

8.3 Pre-loading Operations

8.4 Cooldown for Loading

8.5 Ramp-up to Bulk Rate

8.6 Bulk Rate Loading

8.7 Ramp-down

8.8 Post-loading Operations

8.9 Departure from Load Port

9 Laden Voyage

9.1 Overview

9.2 Laden Voyage of LNG Carriers with Gas Burning Propulsion System

9.3 Laden Voyage of LNG Carriers with Reliquefication Plant

9.4 Further Considerations on Laden Voyage

10 Discharge Operations

10.1 Overview

10.2 Preparation for Discharge

10.3 Pre-discharge Operations

10.4 Ramp-up to Bulk Rate

10.5 Operational Description – Bulk Rate Discharge

10.6 Ramp-down

10.7 Post-discharge Operations

10.8 Departure from Discharge Port

10.9 Further Considerations During Discharge

11 Ballast Voyage

11.1 Overview

11.2 Heel Management

11.3 Further Considerations on Ballast Voyage

12 Ship to Ship Transfer Operations

12.1 Pre-arrival Stage

12.2 Approach and Mooring Stage

12.3 Cargo Transfer Stage

12.4 Post-transfer Procedure

Section 4: Pre Dry-dock Preparations

13 Cargo Tank Operations

13.1 Warming up Cargo Tanks

13.2 Inerting of Cargo Tanks

13.3 Aeration of Cargo Tanks

Glossary

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