During his presentation at the last GREEN4SEA Conference, Mr. Kostas Vlachos, COO, Latsco Marine Management, presented why LPG as a fuel should be considered as a viable option in a strategy toward decarbonization.
The shipping industry is about to face many challenges at the next decade: SOx regulations in 2020, NOx with Tier I, Tier II and Tier III requirements, the Particulate Matter as of Regulation 14 of ANNEX VI of MARPOL and the CO2 regulations with SEEMP and EEDI, which are coming with more requirements in the decade 2020-2030.
The available options for 2020 are well-known. The LPG is available, it is quite safe solution, it offers a redundancy as a dual-fuel main engine and can be used in LPG carriers very easily as these ships carry LPG as a cargo.
The negative things are the cost for retrofitting or installation for the time being is quite high: We have made an estimation and the cost is around 10-12 million for this retrofitting depending on the time you need to make the commission.
Another negative thing is that, for the time being, we have a little experience from the operation of LPG carriers with dual-fuel engine. The main challenge for us, as operators, is the non-availability of four-stroke main engines, which means the auxiliary main engines.
LPG as marine fuel is worthy considering as a viable fuel for compliance because it totally meets the SOx requirements. Also, it is a potential fuel cost saving solution because of its calorific value compared to HFO. Depending on the speculation for the variations of the cost in fuels in the future, we have a more steady solution and the retrofitting of existing ME-main engine aspect as per MAN is quite easy.
The contribution to emissions for LNG and LPG carriers: For LNG, we have 30% reduction in NOx. For LPG, we have 15% reduction in NOx, up to 100% for SOx, 90% for PM and up to 18% for CO2, as opposed to 24% that LNG provides.
The LPG fuel main engine ME/LGIP is quite reliable solution and has the advantage of changing from fuel oil to LPG. The main advantage for this solution is the solutions that are offered for bunkering. LPG can be found everywhere, you can get the bunkering through an STS operation, there are a lot of small pressurized LPG carriers of 3,000 tons dw. You may use as well the cargo that you carry on your cargo tanks, provided that you have permission from the charterers and therefore there is no need to deviate for bunkering and there is no such a big problem as it is with LNG network bunkering that you need to install before you go for this solution.
Talking about the Fuel Tank Flexibility, I shall make a reference to the LPG carriers. We have two solutions: The first one is to install deck tanks on the main deck and the second is to use the cargo tanks as storage tanks.
The first solution can be done with two ways: The first way is to install a semi-pressurized deck tank and the second solution is to install a fully pressurized deck tank with a pressure up to 20 barg. The advantage of the second solution is that you don’t need a liquefaction plant, but the disadvantage is that you need more steel and more weight.
The advantage of the first solution with the semi-pressurized deck tank is that you need less weight and maybe less footprint, but you need a liquefaction plant or you will use the liquefaction plant that you use for the cargo operation.
Another one solution, launched from the builders, is the increased capacity of the cargo tanks, so that part of the cargo to be used for the purposes of LPG as a fuel. Of course, here we have to do some homework with the charterers in order to convince them to prepare with them and other associations so that this use of LPG from the cargo tank to be done without problems with the receivers, the shippers and all involved stakeholders.
The advantage for using the cargo tank as a storage tank is that you don’t need to have deck tanks. Our calculations for a voyage from US to Japan and return back to Singapore for taking fuel again is that for a vessel of 18,000 cb LPG carrier, you need 1,918 metric tons which means as a capacity – for semi-ref- 3,700 cubic meters and -for fully pressurized- 4,500 cubic meters.
Of course, you can use deck tanks only for the ballast voyage and in this case the capacity you need is half of it, which means 1,850 cubic meters.
A comparison about return in the investment is more than 7 years for a retrofitting solution, taking into account that the cost for retrofitting solution is around 11 million.
The main engine operating range for LPG:
-LPG is supplied on medium pressure and injected as a liquid on high pressure 40-50 bar.
-Any combination of propane or butane can be used as a fuel under the provision that the ethane is up to 12%. We need clarity of this propane which means that the sediments must be removed before used in the main engine.
-Always you need 3% pilot fuel oil
-At low rpm only Pilot fuel will be burned.
-Below the 10% you always need to use the fuel option because at the lower rpm the LPG injection valve can’t be controlled sufficiently due to inertia of the valve.
At this point, I would like to make a reference that the main problem is not the retrofitting of the main engine itself, but the provision and the installation which may create some problems during the testing and commissioning.
In summary, the reasons for using LPG as a fuel is firstly, the environmental benefits and secondly that you have better efficiency because of the better calorific value compare to the fuel oil. It is a solution to the future: You cannot talk anymore about HFO in the decade 2030 when we see so many requirements that are coming from IMO about the CO2 emissions and the GHG emissions. There is something more: The dual-fuel main engine is a reliable engine, a clean engine, that will not create any pollution problems, specifically in environmentally sensitive areas, and this must be taken as an advantage.
There are of course some challenges in this solution:
-The higher cost compared with the cost of scrubbers.
-The deck tanks capacity and high foot print that you need.
– The LPG fuel must be clean without extras particulates
-If you use cargo tanks as storage you transfer higher DWT without commercial benefit
– For auxiliary engines you shall continue to use compliant fuel for a long time ahead, unless toy adopt the solution of turbines.
There are also safety considerations:
-LPG is known as an “extremely flammable gas” with flammability limits between 1.0 vol% and 12 vol% in air. Special considerations must be taken for the double wall piping, especially in the engine room with pressure between 40-50 bars. The annual space will be flashed and monitored continuously, while addition as gas detection will be located at the bottom of the engine room.
– A HAZIP- HAZOP analysis is necessary to be run by the operator before deciding to go for this solution which means that alone with the makers, the classification society, the builders, all safety considerations must be taken into account before deciding to go for this solution.
We have run as a company such a hazid-hazop analysis with builders HHI, with Wartsila as gas provider, with DNV GL as class, and USCG, so we are confident that this solution can find acceptance by a lot of stakeholders in shipping.
Proper mitigating measures for LPG
- The entire LPG fuel supply and conditioning system will be installed on main deck, in the already existing hazardous area
- The piping with LPG at 50 barg will be minimized in length as much as possible to limit the inventory and will be fully welded
- Additional gas detection will be installed in the bottom of the engine room
- All piping containing LPG liquid or vapor installed in the engine room will be installed as double walled piping
- The annular space will be flushed and monitored
My recommendation for someone before going to this solution is:
- Compare the cost and return of the investment
- Make sure that all of the safety considerations have been taken into account
- Have in mind that gas is a solution for the future.
Above text is an edited version of Mr. Vlachos’ presentation during the 2019 GREEN4SEA Conference.
You may view his video presentation herebelow
The views presented hereabove are only those of the author and not necessarily those of SAFETY4SEA and are for information sharing and discussion purposes only.
Kostas Vlachos, COO, Latsco Shipping Ltd
Kostas Vlachos is Mechanical / Electrical Engineer graduated from Technical University of Athens in 1981. From 1982 to 1996 he served in the Merchant Ships Inspectorate of the Greek Ministry of Merchantile Marine in various positions with the most important that of MARPOL Convention department head and ISM implementation department head. In the same period he was a Member of the Greek delegation in IMO as well as in various EU committees and subcommittees in Maritime Safety Committee and MEPC (Marine Environment Protection Committee). In 1997 he joined the Consolidated Marine Management Inc. as DPA/DMR and as Marine, Safety & Quality Manager.In February 2005 he assumed the duties of the COO/Managing Director of the Company having full control and responsibilities on all activities and departments of the Company. Starting from 1st January 2019, Consolidated Marine Management Inc. has changed its name to Latsco Marine Management Inc. He is a member of ABS, DNV, LRS, technical committees. In 2013, he was elected Chairman of Intertanko Hellenic Mediterranean Panel & Council member. Since 2014 he is a member of the executive committee of Intertanko, and ISTEC member.
