In recent years, emission control area (ECA) legislation and the high price of fuel has led to shipowners seeking alternatives to oil as a marine fuel
Liquefied natural gas (LNG) has been used on a relatively small scale up to now as the main alternative to fuel oil, and the main types of ships to use LNG so far have been small ferries, cruise vessels or offshore vessels. That is all set to change over the coming years as a much wider variety of type and size of ships start to use LNG as their main fuel.
Of the LNG fuel gas systems (FGS) produced used so far, 100% have been low-pressure systems with a maximum system pressure of 10Bar and there are a wide range of companies which can supply cryogenic valves for these systems. However, with the introduction of the MAN ME-GI, 2-stroke gas engine, high-pressure FGS are now set to become a familiar sight in the enginerooms of ships. Supplying equipment for high-pressure FGS is a much more specialist area as these systems operate up to 430Bar pressure.
The MAN ME-GI engine that was launched in the past year requires the gas to be injected at around 320Bar into the engine cylinders to ensure effective combustion of the gas. MAN is now developing the same engines to burn ethane and these require the gas to be injected at over 400Bar pressure. Cryogenic valves need to be developed to withstand these higher pressures and Parker Bestobell Marine is well placed to be involved in this market sector.
The latest MAN ME-GI engines enable efficient ship propulsion and offer lower emission values that can assist with meeting current environmental limits in ECA areas. They also contribute to an overall improvement in energy efficiency. A high-pressure gas injection dual-fuel 2-stroke engine with higher system efficiency offers a significant reduction in emissions for LNG carriers, as well as other ocean-going vessels.
A high-pressure gas injection dual-fuel 2-stroke engine with higher system efficiency offers a significant reduction in emissions for LNG carriers
Understanding marine rules
This has created a market opportunity for specialist marine cryogenic valve manufacturers, like Parker Bestobell Marine, to respond with high-pressure valves. Innovation within our product portfolio means Parker Bestobell Marine has developed a new range of Class 2500 and are developing a range Class 4500 valves that can operate at these pressures. These valves will be prototype-tested and type-approved by the relevant marine classification societies. This is a rigorous process and one where experience in the marine sector is vitally important.
Manufacturers of high-pressure cryogenic valves looking to expand their markets by moving into the marine sector would have to adapt their products to suit marine requirements and, more importantly, to understand how to get their products approved. For companies that do not already operate in the marine sector, this is a huge learning curve to understand marine rules and there is great difficulty in doing so, as the requirements of the marine classification societies are very exacting.
Specifying high-pressure valves
There are many considerations for the marine industry when specifying high-pressure valves. Valves must have a valid prototype test certificate issued by one of the major classification societies – this means being tested to 1.5 x design pressure. They must also have type-approval from each of the major classification societies. In addition, they must be fire safe – so all components can withstand a temperature of 925°C or above without leaking. All valves must be of stainless steel design, with butt weld end connections for the liquid phase. 100% ambient testing may be required of the seat and body of the valve, and 10% cryogenic testing of each size and type of valve. In addition, full 3.2 document/certification traceability is required on all casting and billets.
A barrier to entering this market is that the requirements of the classification societies will not be understood by companies that do not have marine cryogenic valve experience. Parker Bestobell Marine has huge experience in this area having supplied, or contracted to supply valves to over 200 ships, and have over 35,000 cryogenic valves fitted on ships. This type of experience cannot be matched by new entrants into the marine sector. All valves – whether high or low pressure – need to comply with the classification society rules.
MAN ME-GI engines across the world
There has been a surge in orders for the MAN ME-GI gas engines in recent months, with upwards of 30 new vessels contracted that will use this type of engine. This means there is now a requirement for 30 high-pressure FGS to supply the gas for these engines. Parker Bestobell Marine is actively involved with the FGS equipment builders and aims to be involved in most of these projects. In total, there are around 50 vessels contracted with MAN ME-GI engines across the world.
MAN ME-GI engines have now been adopted by DSME for its LNGC ships and is offered to owners in conjunction with DSME’s Hi-VAR FGS, that includes a partial reliquefaction system. This can liquefy excess boil off gas (BOG) from the cargo tanks that is not used for the fuel. It has proven to be very attractive to shipowners, as it offers them substantial savings in vessel running costs and as a result, DSME has taken a much larger share of the South Korean newbuild market for LNGCs compared to its competitors.
As mentioned previously, Parker Bestobell Marine has developed a Class 2500 range of valves that can work up to 370Bar pressure and as a company, we are now developing a Class 4500 range of valves to operate over 600Bar pressure. This new set of valves are required for FGS where ethane is used as the fuel. Liquid ethane has not traditionally been carried on ships, but with the development of the shale gas fields in the USA, not only are there large quantities of methane (natural gas) but also wet gases like ethane, propane and butane, which could also be used as a fuel when carried as a cargo.
In the future, there is set to be significant growth in the marine sector for high-pressure cryogenic valves as more shipowners are adopting MAN ME-GI engines for their newbuild vessels. MAN is also working proactively to market these gas engines to shipowners, securing a higher level of sales. It is currently only the MAN engine that requires the high-pressure gas injection, so the application is limited in terms of the overall gas engine market to the ME-GI engine. However, MAN does command about 80% market share of the 2-stroke engine market, so there are major opportunities here.
“In the future, there is set to be significant growth in the marine sector for high-pressure cryogenic valves as more ship owners are adopting the MAN ME-GI engines”
Noel Doidge, Product Manager, Parker Bestobell