Technical Development Manager, National Grid Grain LNG
National Grid Grain LNG, GIIGNL Technical Study Group
11:15 - 11:45
Thursday, 19 September 2019
T1.8 Guidelines for reloading of LNG carriers at import terminals
Due to unprecedented change in the worldwide LNG industry, the traditional role of LNG import terminals is changing. LNG import terminals have modified their assets to reload LNG carriers in order to meet new customer requirements - including the need for destination and volume flexibility - as well as to access the emerging retail LNG market. Whilst this idea may seem straightforward to implement, there are numerous technical risks and challenges that need to be considered. This document serves as a reference manual to share and drive best practice across the industry and to ensure that the challenges in carrying out reloading of LNG carriers are properly addressed.
The GIIGNL membership is comprised of nearly all LNG terminal operators worldwide. This document was developed using the experience of GIIGNL import terminal operators.
- Typical reload plant lineouts for of a purpose-built import terminal
Different operating modes of reloading at a typical import terminal are considered and illustrated (e.g. typical single ship reload, multiple ship reload, and jetty-to-jetty transfer) and the key challenges of each operating mode are discussed.
- Technical assessment of adapting and debottlenecking import facilities for reloading
- Surge studies analysing the hydraulic and dynamic forces of the transfer lines due to change in mode of operation;
- Possible strategies for achieving flow through jetty process pipe with non-return valves installed on loading arms to protect against reverse flow during unloading operation;
- Terminal boil-off gas facilities debottlenecking, which may include compressors and coolers;
- Consideration for utilising in-tank pumps for reloading, which may have been originally intended for other purposes such as providing LNG for recirculation or export;
- Control / ESD System modifications.
- Risk analysis and formal process safety assessments
Risk assessment and formal process safety studies are required to ensure that risks to people and the environment have been eliminated/mitigated when performing reloads. This paper describes the operations that should be considered, the process safety assessments which should be conducted, and the fundamental principles for risk assessment and reduction required.
- Responsibilities of various stakeholders
The key stakeholders are the import terminal, the LNG carrier operator, the port authority and the emergency services. The paper outlines the different levels of responsibility for each stakeholder, at different stages of the process, to ensure reloads are performed in a safe and efficient manner.
Several import terminals have now been adapted for reloading operations. Based on the experience of its members, GIIGNL recommends that thorough consideration be given to the technical best practices discussed in this document. In order to enable successful reloading operations, careful attention should also be paid to risk assessment and safety procedures, as well as to defining the respective responsibilities of the various stakeholders.