GST®, the membrane Full Integrity System for LNG Land Storage Tanks
Expert in maritime storage and transportation of LNG, GTT has developed its own onshore storage design: GST® Membrane Full integrity system, adapted for small and big capacities.
GST® benefits from a strong experience in land storage systems: 33 tanks have already been built Worldwide. GST® Membrane Full integrity system is derived from Mark III technology which benefits from more than 30 years of experience at sea. It is fully compliant with international standards, and offers one of the highest safety levels.
- Separation of the main functions
The GST® concept is based on a clear separation of the 3 main functions required from a land storage tank; tightness, thermal insulation and structural resistance.
- Tightness is provided through the two membranes (primary and secondary)
- Thermal insulation through the insulating panels
- Structural resistance through the concrete walls (designed for inner and outer loads)
- Prefabricated modular elements
The GST® technology consists of a combination of a limited number of modular basic shaped components that can be manufactured by normal industrial processes.
The elements composing the membrane sheet layer as well as the insulating panels (typically 1m x 3m) are prefabricated and fitted together on site.
- GST® containment system
- Flexible (1.2mm) stainless steel membrane.
- The double network of corrugations absorbs the thermal contractions resulting from the very low temperature of the LNG.
The thickness of the panels can be adjusted to provide a large range of boil-off rates according to the operator’s requirements (typically 0.05% per day).
The outer concrete container provides the structural resistance to internal and external loads. A moisture barrier, applied on its inner side, prevents moisture from entering the tank.
Thermal Protection System (TPS) – bottom up to 5m: a composite laminated material.
This consists of a thin sheet of aluminium between two layers of glass cloth and resin. In the event of a failure of the primary membrane, it prevents the build-up of stress concentrations on the concrete corner and ensures the liquid tightness of the concrete wall, as required by European standards.
- Full containment solution
- Excellent track record
- Certified by renowned third parties
- No theoretical limit of capacity
- Significant higher net volume for given dimensions
- Sump pit
- Ease of Design
- 95% of components are standard
- Well adapted to harsh seismic conditions
- Boil-off rate adapted to client’s specifications
- Same design pattern whatever the capacity
- Ease of Procurement
- Limited weight of Stainless steel
- Economy of Scale: streamlined with LNG carrier supply chain
- Only 3 weeks production for a conventional tank
- Ease of Construction
- Simpler concrete construction
- High ratio of prefabrication
- 85% automatic welding (TIG process without added filler metal), only one welding pass
- Favorable construction process for local workmanship
- Saving on erection schedule
- Ease of Operation & Maintenance
- Almost no restrictions on cooling down rate
- Faster decommissioning if necessary
- No maintenance
- Up to 20% of the total cost of the tank saved compared to 9% Ni
- Less dependent on Nickel price and raw material stock limitation than 9% Ni
- A standard and non-exclusive License Agreement with EPC, allowing an open competition between bidders
Membrane Full Integrity and 9% Ni Full Containment systems have some similar positive attributes:
- Ensure containment functions (LNG+NG) under normal & accidental conditions
- Thermal Corner Protection for a high level of safety
Membrane technologie has additional competitive advantages:
- Safety (Earthquake, Tsunami)
- Carbon Footprint (up to 25% less)
- Cost & Schedule (3 to 4 months less)