CNG storage vessel nears ABS design approval

CNG storage vessel nears ABS design approval
The CNG Optimum ship design. Image courtesy of Global Energy Ventures

Australian company Global Energy Ventures (GEV), developer of global integrated compressed natural gas (CNG) projects has completed two of the three ABS tests required for design approval of its CNG Optimum ship.

The CNG Optimum is a marine CNG storage vessel. It is the result of two decades of CNG development and is designed to transport CNG over regional distances up to 2,500km. It has the flexibility to deliver gas from volumes of 50 to 400 MMscf/d, with small to medium gas reserves (< 1.0 TCF).

According to GEV, the Optimum ship design maximises the amount of CNG that can be stored within the hull of a ship. The Optimum containment system is constructed using close-packed, high strength pipes that run the entire length of the ship’s cargo hold.

According to GEV, there has been rapid CNG project development over the last three years, making it more accessible to the market. At the end of field or project life, CNG Ships can be easily re-deployed.

GEV’s CNG Optimum ship has received in-principal approval from ABS with final testing due soon. If the CNG design completes the final test, it will receive an ABS Design Approval. At present, the company is working with four shipyards to determine scheduling and costs of using natural gas in international shipping.

In October, the project completed bend and friction testing, verifying that the CNG containment pipes in the hold of the ships can be forced together without movement of the pipes. GEV developed a mechanism to clamp the gas storage pipes so tightly together that they become locked together as one, allows this design to meet all classification requirements. The tests replicated a downward force that would be applied on the pipes in a ship’s hold.

According to GEV, previous work on this type of system failed due to rubbing of the pipes as the ship moved in response to sea conditions.

The final test will involve a fatigue test. This is a vigorous test that will require cycling a pressure vessel for ten times its design life, from minimum pressure to operating pressure.

Ship design and engineering are being finalised ready for construction by the shipyards in the first half of 2019. GEV expects the first CNG Optimum ship to be in service by early 2022.

GEV chairman & CEO Maurice Brand previously said: “We are approaching the end of the ABS Full Class approvals process with outstanding results being achieved. Importantly GEV can now confidently move forward with the only remaining testing phase required before the CNG Optimum ship design has been proved.”