Vessel owners and operators need to develop a ‘bunker checklist’ and careful maintenance practices to ensure their diesel engines are ready for the changes required by the IMO 2020 sulphur cap, writes Royston technical director Neil Graham
The IMO 2020 sulphur cap came into effect 1 January, lowering the Marpol Annex VI global fuel sulphur cap from 3.5% to 0.50% and prohibiting the carriage of non-compliant fuel. The main aim of the new regulation is to ensure marine engines use a low-sulphur HFO or marine distillate oils, which already comply with low sulphur regulations.
The move is aimed at curbing SOx pollution produced by ships and represents a very significant, industrywide event, which will likely have far-reaching effects on the global shipping industry for many years to come.
SOx released into the atmosphere via a ship’s exhaust gas combines with NO2 – which acts as a catalyst – and other compounds to form sulphuric acid. This can contribute to acid rain forming and cause damage to the quality of air, water, soil and food. It can also have a detrimental effect on the ozone layer and thereby contribute to global warming.
Shipowners, vessel managers and crews must ensure they understand the issues and that their vessels are provided with fuel oil suitable for use by marine engine power plants. If any problems arise, these must be addressed to minimise any impact.
An alternative to burning low sulphur fuel is to install post-combustion treatments such as an exhaust gas cleaning system or scrubber to curb SOx. However, due to the large capex requirement and time out of service for installation, only a small percentage of shipowners are opting for scrubbers, with most opting for compliant fuels.
One of the concerns with implementing the 0.50% sulphur cap was the availability of very low and ultra-low sulphur HFO, but it appears suppliers have responded to the demand. Possibly of greater concern is how long high sulphur HFO will remain available or if the price will get closer to the low sulphur fuels, affecting the ROI of owners who opt for scrubbers.
Incompatibility of bunker stems may leave shipowners facing serious engine repairs, requiring vessels to be taken out of service and leading to serious loss of earnings for operators. Mixing non-compatible fuels can lead to sediment forming in the tanks which can block filters and purifiers. Add the risk of asphaltenes and cat-fines in certain fuels, then stemming good quality fuel and good onboard management is essential to avoid damage to the engines and fuel systems.
The nature and type of fuel oils that will be available are expected to differ significantly. Different fuel mixes – a variety of blends – will mean practical steps need to be taken to secure quality control. Industry good practice proposes developing a ‘bunker checklist’ to supplement the vessel’s own safety management system procedures – a list of checks and tasks from pre-bunkering through bunkering to final completion and disconnection – see also IMO’s Ship Implementation Plan.
Fuel segregation between bunker sources will also become a feature of future operations until all sources of fuel can be proven to be stable, mixable and compatible with each other. Smaller bunker orders may become more common to avoid mixing different fuel supplies. Fuel monitoring will be increasingly important to avoid poor quality fuel reaching the engine, as well as running purifiers at their optimum settings ie the right fuel oil temperature and the correct throughput (slow as possible). Checks by port authorities on compliance, especially in ECAs, will increase and it may not be long before onboard testing of sulphur content and emissions measurement becomes the norm.
Lower sulphur content in fuels will contribute to decreased levels of ‘lubricity’ in engines, contributing to increased wear and tear in fuel pumps and requiring additional injector maintenance. These components have high tolerances and most manufacturers of fuel pumps have already moved towards a higher material specification for their plungers and often use a diamond-like carbon coating to reduce wear. These coatings are extremely hard, corrosion resistant and have ultra-low coefficients of friction. They can also be deposited with a high-degree of control of the coating thickness.
If the decision is made to move away from high sulphur HFO and scrubbers, cleaning pipes and storage tanks will need careful planning and inevitably result in substantial costs and downtime.
Manual cleaning is time consuming, and again may result in downtime for the ship if not carefully planned.
Recommended best practice is to flush through the system with distillate and afterwards dispose of it as waste oil. It is a very competitive supply, so consider quality, versatility as well as cost effectiveness of a potential service partner.
As stated earlier, some ships will limit the SOx air pollution by installing scrubbers. This is accepted by flag states as an alternative means to meet the sulphur limit requirement. These scrubbers are designed to remove SOx from the ship’s engine and boiler exhaust gases. A ship fitted with a scrubber can use high sulphur HFO since the SOx emissions will be reduced to a level equivalent to the required fuel oil sulphur limit. The most likely ships to install scrubbers are larger deepsea vessels which have high fuel consumptions and crucially have the space in the engineroom to fit this equipment. A fuel consumption rate of 50 tonnes/day seems to be an accepted cut-off point for fitting a scrubber and still obtaining a reasonable ROI, within about five years.
LNG as a fuel
What is the alternative to burning low sulphur fuel or using scrubbers? Converting engines to operate on liquefied natural gas (LNG) will provide considerable reductions in fuel costs as well as reducing emissions, including SOx. Check if existing engines can be converted to gas, or if new engines are required (dual-fuel or pure gas). Finding space in the engineroom for the storage tanks is key and, depending on whether the engines are converted to dual-fuel or pure gas, there may still need to be a liquid fuel storage system as well.
Underpinning the aims of IMO 2020 sulphur cap is a need to improve fuel consumption for the ship operator, and thereby keep costs to an acceptable limit and reduce all exhaust gas emissions, including SOx and CO2. Implementing advanced technologies such as ‘Eco Speed’ – a recent development in Royston’s enginei fuel monitoring system – allows vessel operators and owners to determine the most economical speed against the best fuel consumption for any particular vessel.
There is an obvious need to pay close attention to the detail in the project management and planning of service jobs in meeting the requirements around IMO 2020 sulphur cap. Careful review of the options (low sulphur fuel or high sulphur fuel plus scrubber or conversion to LNG) around practicalities and ROI should be made, with a project management team appointed. Independent service providers such as Royston can focus on providing a fully responsive engineering service geared towards meeting the specific timing, location and technical needs of a customer facing IMO 2020 sulphur cap compliance issues. The company can provide project management in collaboration with the relevant engine or scrubber manufacturers, as well as supervising installations, fuel system cleaning and tank segregation.
Riviera’s Maritime Air Pollution, Americas Conference will explore vessel owner/operator experiences with their chosen IMO 2020 compliance technologies including fuels, lubricants, engines and scrubbers on 5-6 March 2020 in Miami, USA. Book your ticket now