Inert gas generation is the latest onboard operation to be subjected to the optimisation process and with owners looking to future-proof their vessels against regulatory change, this standardised equipment is having to play catch up
The commoditisation and resulting standardisation of tankers took place as long ago as the 1970s, when the VLCC-sized tanker first appeared. Placed alongside a 2020-built vessel and there is barely any discernible difference between the two. The same process has happened to the equipment required for onboard loading and cargo handling. New equipment is introduced to meet new regulations and soon this equipment is similarly standardised and commoditised. This same process has happened to inert gas generators, albeit with relatively few leaps forward in innovation or technology in recent years.
However, the need to reduce the sulphur and carbon footprint has added new impetus to the development drive; tanker owners and operators are now looking for even marginal gains from the equipment already onboard.
An inert gas system (IGS) can produce inert gas based on either nitrogen or carbon dioxide. Those based on carbon dioxide can be divided into inert gas generators, burning fuel oil, and flue gas systems, utilising the boiler flue gas. These systems need to comply with Marpol Annex VI, which states that sulphur content requirements apply for “any fuel oil used on board the ship”.
Alfa Laval’s sales director for inert gas systems, Marko van der Smitte says: “One example of this development is the integration of the Alfa Laval Automatic Fuel Efficiency Module (AFEM) into our inert gas generators (IGG) for product tankers, both for newbuilds and as a retrofit package. This module significantly reduces fuel consumption by generating the exact amount of inert gas required. We see average fuel savings of around 30%, with a corresponding reduction in emissions.”
The AFEM takes over the active control of the oxygen and through a closed-loop process, could achieve a further 15% reduction in fuel consumption, notes Marko van der Smitte.
The company can also integrate its flue gas system across other Alfa Laval products, combining Alfa Laval’s Aalborg Boilers, Smit Flue Gas Systems and PureSOx Exhaust Gas Cleaning system. This set up complies with the requirements of Marpol Annex VI, as mandated by IMO’s Marine Environment Protection Committee (MEPC).
IMO’s low carbon and zero carbon goals could have an impact on how inert gas is generated in tankers. Mr van der Smitte says: “There are currently no regulations regarding emissions from IGS, although these could be regulated as we move towards the 2030 and 2050 dates that IMO has set for GHG reduction. We keep a close eye on regulations and investigate alternatives to ensure our customers are meeting compliance. Alfa Laval is part of the Getting To Zero Coalition, which is driving the development of sustainable technology that will enable zero-emission vessels by 2030.”
Wärtsilä is another provider of marine equipment and has been in the inert gas sector for more than five decades, through its Moss and Hamworthy brands. The company has over 2,500 vessels on its reference list.
It produces inert gas systems for crude oil tankers, product tankers, chemical carriers and for LPG and LNG gas carries and the offshore market. The FPSO sector is one of Wärtsilä’s primary markets at the moment, with the retrofitting of an inert gas system often part of the general refurbishment and upgrading of the original equipment installed on the vessel.
Still, Wärtsilä general manager of the oil & gas division, inert gas systems, Geir Hellum says that the market for inert gas systems is almost entirely predicated on newbuildings. “The regulations requiring inert gas systems have effectively been in place since the 1970s,” he says. “Our systems are installed in the newbuilding while it is under construction and they last as long as the ship,” he adds.
Making the right decision
But who decides on the fitment of a particular make of inert gas system for a tanker? “That decision is nearly always taken by the shipyard,” says Mr Hellum. Being on the shipyard maker’s list is vitally important; but achieving a place on the list is not always easy and often depends on one key criteria: “It is always cost,” says Mr Hellum. “The yard will have made an agreement to a make and model on the maker’s list.”
But it is up to the owners to sign off on the equipment that is on the maker’s list and therefore to ultimately determine what is fitted to a newbuilding. If the owner wishes to have a different inert gas system fitted to that on the maker’s list, an extra cost will be incurred.
“Some owners are much more active in choosing the make and model specifications,” says Mr Hellum. “They may have a series of ships and wish to standardise training across the fleet. It is also important to note that the owner’s experience of the service and spare parts network is an important factor,” he adds.
“Owners are asking more pertinent questions regarding fuel consumption and emissions,” says Mr Hellum. “Some customers are paying close attention to the current regulations and what regulations they expect in the future and what will affect the ship in 20 or 30 years’ time.”
And will this search for ever lower fuel consumption and emissions mean less flue gas output and an increase in demand for nitrogen systems? Mr Hellum doesn’t think so: “The nitrogen system is more expensive and is used in chemical carriers, where there are cargo contamination sensitivities.”
As well as the cost function, there are question marks as to whether a nitrogen-based system would have the capacity to service the requirements of larger tankers. Would producing sufficient quantities of nitrogen to meet the demands of a larger tanker in itself require an increase in energy requirements?
The move to alternative fuels, such as LNG, should not produce any fundamental changes in the inert gas market. There is still a need for inert gas systems in multiple aapplicatins, and many vessels will still retain diesel generators for auxiliary power and boilers for steam.
But the location of Wärtsilä’s manufacturing base in China could present short-term issues: “We are starting to see some delays with the shipyards in China due to the [Covid-19] coronavirus, says Mr Hellum. “Some ships are not as ready to accept parts as they should be. This is also affecting shipyards in South Korea. We are not the only supplier to be affected by Coronavirus. It is impacting across all suppliers.”