The rapid growth of the LNG market has been created by demand for bigger ships amidst a backdrop of high incomes and revenues. LNG ships currently being ordered are bigger some with carrying capacities of more than two hundred thousand cubic metres and summer drafts of 12m. It means that due to the size the ships cannot access the shallow ports and thus there arises a need to transfer the LNG hence, LNG ship to ship transfer.
LNG ship to ship transfer (LNG STS) is enabled by having both vessels held in position against each other while the cargo ship pumps the liquefied gas through flexible hoses. Numerous LNG ship to ship transfers take place with incidences and accidents being quite low due to the advances in technology that have made it possible to manage risks associated with the LNG STS transfer.
A vital part of all LNG STS transfer systems is the Emergency Release System (ERS). Due to advancements in safety technology, the emergency release system consists of numerous parts including the Emergency releases coupling (ERC). Usually, we have more than one ERC within the ERS. The ERC ensures that in case of an emergency the ship crew can contain the situation and isolate the operations and the cargo system. It is mandatory for all vessels to protect the environment as much as possible through preventing cargo spills. An emergency release system is ideal to achieve this as it protects the cargo hoses and the ship from damage.
The Emergency Release Coupling has improved the safety standards by providing a weak link or a safe point hence in case of an accident; the crew can anticipate the behaviour of the system. For example, if the ship breaks away unexpectedly, the emergency release coupling has been intentionally designed to shut down the LNG process by separating the hose lines between the vessel and ensure the LNG flow is safe.
Also, LNG Hydraulic power systems are the new cutting-edge safety and technology system. It includes a full safety release ship to ship transfer which further provides an additional fail-safe option. A point to note is that under the HPU system the crew is given a position of control over the emergency release system. In case an emergency release coupling is activated accidentally by anything other than hose line stress, the process can be restored by the crew meaning LNG transfer can continue. An exciting additional advance in the technology is that the HPU can contain different variables such that a release of the couplings will be dependent on each scenario and the set parameters. Also, this means that a single HPU can control an entire system of more than ten emergency release couplings hence, reducing the time the operator has of checking the whole system. It measures and instigates the efficient and safe close down of the system. HPU is the most advanced technology in the market had has been in use with massive success rates. Further advances in the release system are still ongoing and are expected over the coming years.
It is necessary for all crew to have adequate and through training on LNG proper handling procedures. The training usually includes primary and supplementary learning for deck engineers