Danish Innovation for Sustainable Shipping

Eltronic in Hedensted developed a special safety system to control the gas supply to marine engines: this compact state-of-the-art solution purges the pipes with nitrogen once the gas has been turned off. Report by Siemens AG’s Sales Developer OEM, Tobias Wachtmann, and Hans Joern Schmidt, Sales Process Instrumentation.

2008, the IMO passed a resolution that ships must reduce their emission of dangerous substances like sulfur oxide (SOX) and nitrogen oxide (NOX). This new resolution stipulates that large vessels must not use heavy fuel oil when passing through special environmental zones, such as the Baltic Sea, the North Sea and the coasts of the United States and Canada.

One of the alternatives to heavy fuel oil operation of marine engines is natural gas (methane). However, the use and storage of natural gas onboard vessels is a safety issue.

Marine classification societies are therefore specifying that the highest quality safety systems are installed onboard every vessel, which quickly, reliably and safely turns off the gas supply if an emergency situation develops. Simultaneously, the safety system allows the piping to be purged with nitrogen, therefore eliminating any fire hazard when the vessel is not operational.

Eltronic has developed the new GVTs in close cooperation with specialists from Siemens. Here, Hans Jørn Schmidt (left) from Siemens Denmark is discussing the details with Project Manager Peter Lilholm

GVT Increases Safety

In order to meet these challenges, Eltronic in Hedensted has developed a special safety system capable of safely and reliably switching off the gas supply, while also removing natural gas residue from the feeder pipes – known as a gas valve train (GVT).

“All marine classification companies that also insure vessels demand safety equipment like this when steaming with natural gas”, explained Eltronic Project Manager Peter Lilholm.

The idea behind the gas protection is also known as double-block and bleed. It consists of a special unit with three main valves and six auxiliary valves. In the case of an emergency, when the gas supply has to be switched off, valves located on the engine side and on the gas supply side are closed. Another valve opens in the middle, venting residual gas to the environment. The system is purged with nitrogen – an inert gas that represses the flammable gas. 

“Our GVT can be purged either way, so both the pipes facing the gas supply and the engine are purged of any methane,” explained Mr Lilholm.

Depending on the conditions on board, Eltronic GVT can be installed close to the gas supply, the engine or somewhere in between the two.

Second Generation

This engineering company, located in Jutland, Denmark, is rather modest when talking about their GVT – although Eltronic has been the technological pioneer in this segment for several years. 

It is a position the company wants to keep which is why Eltronic’s staff have already developed the second generation.

“Our first version is a steel block with one inch channels. The newly developed version is available in three different sizes of one, one and a half and two inches for natural gas and ethane. We were also able to increase the operating pressure from 300 bar to 380 bar, which means that today's equipment has been pressure tested for up to 630 bar, according to the classification requirements,” said Mr Lilholm.

The new compact design reduces the size of the new GVT down to almost a cubic meter as the valves have been able to be mounted closely to one another around the steel block.

“In the new version we also optimised the gas flow, reduced the pressure drop and made it easier to access the various components. This means a lot on board a vessel where space is money,” added Mr Lilholm. “And the new GVT contains less steel, which requires less manufacturing. As a consequence, we have been able to reduce weight and costs, which makes it even more attractive in the market.”

Assembly and testing under the surveillance of marine classification societies, shipyards and customer representatives takes place at the Eltronics factory in Hedenstad, before the GVT is installed in the vessel

World Famous Supplier 

The GVT is an integral part of the ship’s engine management and thus has multiple temperature and pressure sensors.

During the development of the new GVT, Eltronic decided to use Siemens components for all of its sensors.

“Siemens products are world famous and it’s possible to obtain replacement parts worldwide. Further, it makes sense to source all of the components from one supplier – and enter into specific frame agreements,” explained Mr Lilholm. Eltronic is already a Siemens solution partner for several automation technologies, a sound basis to benefit from the comprehensive Siemens product portfolio – including process instrumentation.

There is actually also a second, and rather simple explanation why Eltronic chose Siemens for the new GVT.

“With our previous supplier we had to individually order class approvals for every device. With Siemens components, we can stock one item number and do not have to order devices with individual certification each time, as they comply with almost any standard,” clarified Mr Lilholm.

Siemens Offers General Certifications 

Eltronic also supplies GVTs to land-based static gas engines. This equipment makes it easier to select components and obtain approval for the final configuration.

This is quite a different situation when compared to marine applications where the demands are far higher than for land-based ones. For marine applications, the components involved and the final configuration have to be tested by the specific marine classification company before the GVT are installed and commissioned.

As Siemens components have a wide range of approvals and certificates, the process has been made much smoother, and this is another important reason why Eltronic chose Siemens.