Compressed Natural Gas Transport System
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First results in the liner and hydroforming mould construction

GASVESSEL partners CNG-V, Navalprogetti and BM Plus are working hard on the pilot production of the pressure cylinder, the heart of the Gasvessel innovation. In the past months they have achieved a major result: the first liner is produced.

The liner is the core of the pressure cylinder, designed to contain the compressed natural gas at 300 bar. It is made of very thin austenitic steel, which has good elongation characteristics ideally suited for the hydroforming process. Additionally, it is suited for very low temperature environments, has a great corrosion resistance and is the optimum solution for resisting the action of hydrogen present in the natural gas.

The first liner of the pressure cylinder is about 8 meters long and has a diameter of about 2 meters.

The function of the liner is to support and shape the carbon fibres, which are wrapped externally, and to constitute a gas-tight barrier, which is otherwise not achievable with composites and resins. This first liner will be used to verify the hydroforming process results and the achievement of the requested mechanical characteristics.

The mould that will be used for the hydroforming process is currently under construction. It will be made of high tensile strength steel elements with accurately machined internals that will be welded together. Once it is finished, the liner will be lowered into the mould to be deformed against the internal walls using water pressure. After hydroforming, the liner will reach the required final dimensions and a fair external surface, suitable to receive the subsequent layers of resins and fibres. The first hydroforming is scheduled to take place in the end of June, beginning of July 2018.

Elements of the hydroforming mould. When all elements are welded together, the mould will be 10 meters long with an external diameter of 3 meters and a total weight of more than 28 tons.

The mold is the result of a NAVALPROGETTI design. Highly sophisticated calculations have been made because hydroforming process induces internal stresses of thousands of tons.

BM Plus is constructing a concrete platform of 270m2 where the hydroforming mould will be installed in a vertical position. The plant required for the hydroforming, the water tank and auxiliaries, such as a skid, pumps, electrical motors and a control panel will be installed inside the BM Plus facilities.

The project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 723030.