Royal Belgian Institute of Marine Engineers

Transcription

1 Royal Belgian Institute of Marine Engineers

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3 than other areas of the sea. Annex VI ECA zones, both existing and pending, can be seen in Figure 2. Note that sulfur rules are supported by EU and US EPA regulators and enforcement will be carried out by various governmental organisations. The implementation dates for the ECA zones vary. Enforcement in the Baltic ECA began in May 2006, in the North Sea ECA in November 2007, in the North American ECA in August 2012 and in the North American Caribbean ECA in January Future control areas under consideration include the Mediterranean and the Far East. The global limit on sulfur of 0.5% shown to be implemented in 2020 will be reviewed and decided on in The change may be delayed until Figure 2 shows designated or pending ECAs. Note that ports will be included in the ECA. Emission control areas In order to comply with MARPOL Annex VI, ships travelling in designated ECAs will be forced to operate using marine gas oil (MGO)/marine diesel oil (MDO)/low sulfur fuel oil (LSFO) or by using an exhaust gas cleaning system. In designating an ECA, the IMO defines certain areas of the seas and inland waterways as 'special areas' in which, for technical reasons relating to their ecological condition and sea traffic, the adoption of mandatory pollution prevention is required. Under the Convention, these special areas are provided with a higher level of protection The ripple effect MARPOL Annex VI will have far reaching consequences for refiners. For the vast majority of shippers, the simplest compliance solution is to switch to burning low sulfur fuel in lieu of the higher sulfur fuels currently used. This will impact the prices of both low and high sulfur fuels in an inverse way. It is expected that when the regulations take effect as early as 1 st January, 2015, demand for MGO/MDO/LSFO will increase, driving prices to record highs based on increased demand and creating shortages, while the price of high sulfur fuel oil (HSFO) will decrease to a very low price compared to current price levels. A recent study indicates the differential between marine bunker and gasoil could reach USS 450/t in 2015 and climb steadily in coming years, reaching USS 500/t in 2020 and USS 600/t in The future differential could be higher. For some ships that are particularly active in the ECAs, high MGO/MDO/LSFO prices will be untenable. The costs to the refinery for increasing production of lower sulfur fuels to meet the new marine demand driven by these regulations would be astronomical. In addition, the required revamps to refineries would take years. Currently, it does not appear that any refiners have given much consideration to modifying the refinery to meet the increased LSFO demand.

4 With no increase in supply of these fuels, the lower sulfur fuels will be in great demand, drastically increasing the fuel price. The IMO as well as the EU have said they will not postpone the compliance dates. Hence it is up to savvy ship owners to look for alternative ways to economically comply with the new regulations outside of just switching to low sulfur residual and distillate fuels. Other compliance options each come with their share of financial, technical and operational challenges. In the longer term alternatives such as LNG, biofuels, dimethyl ether (DME) and methanol may provide solutions. However, more and more ships are adopting exhaust gas cleaning systems (EGCS) to absorb SO x out of exhaust gas to the required 0.1% S equivalent. The EGCS offers the flexibility to operate on any kind of bunker both in and out of ECAs. Scrubbing technology: from land to sea As refinery managers around the globe concerned about sulfur emissions have come to know, sulfur emission management can be achieved cost effectively through wet flue gas scrubbing. Flue gas scrubbing technology that has been used successfully for decades on refining fluid catalytic crackers and boilers can be effectively modified to absorb SO x from marine engine and boiler exhaust gases. Wet scrubbing can effectively reduce sulfur emissions to less than the equivalent 0.1% sulfur content requirement. Not only has wet scrubbing been successfully utilised on hundreds of refining applications, it has also been effectively meeting IMO sulfur emission standards on dozens of class certified marine applications. Shipboard scrubbers are the economically viable, low operating expenditure (OPEX) alternative to burning ultra low sulfur fuels. They can be installed with a payback period of less than two years while meeting all IMO equivalent sulfur emissions limits. Marine scrubbers represent a compliance alternative that would allow refinery businesses to continue benefitting from their existing refining process bunker production, while allowing ships to be in full compliance. As the January deadline fast approaches, it seems every week announcements are coming out naming new contracts between scrubber companies and ferry, cruise ships and cargo vessels. Engineering clean air on land and at sea Many similarities can be drawn between the refinery scrubber application and the marine application, though the marine application is somewhat less demanding. In addition to similar process conditions faced in refineries and on ships, of utmost concern in both industries is reliability. The refinery scrubber needs to be extremely reliable especially when installed on the fluid catalytic cracking unit (FCCU). Scheduled turnarounds for the FCCU are 4 6 years, and the scrubber must be operable during this period to match the turnaround schedule. Since the FCCU is the heart of the refinery, unscheduled turnarounds can cost the refinery millions of dollars in lost profit. Marine scrubbing technology also needs to be reliable, and it is no small task to design a system that is robust, high quality, and sleek enough to accommodate the tight spaces available on ships, yet affordable enough to meet a reasonable payback period. BELCO scrubber technology is able to achieve that. BELCO refinery and marine scrubbers use an open tower with spray design, as opposed to the use of packing to trap particles and droplets. Packing is avoided due to the potential of plugging from buildup of particulate and soot as well as other reasons. In the marine space, some companies offer packing designs which use non metallic materials (plastic or glass fibre reinforced plastic (GRP) which can melt or even catch fire during maintenance. Packing also causes the

5 scrubber diameter to be larger as the gas velocity across the packing needs to be lower than the open tower to increase contact time. Packing also contributes additional weight higher up in the ship funnel which can reduce a ship's stability, causing the vessel to be unsteady in rough seas. The Belco scrubber utilises a bottom inlet. Combined with the fact that it is made of high quality, corrosion resistant materials that can withstand high temperatures, this allows the ship to operate in a 'run dry' mode with no active scrubbing when outside of ECAs, eliminating the need for a bypass of the scrubber, and reducing installed costs. Additionally, there is no water retention in the bottom of the scrubber. This not only reduces weight but prevents any scrubber water from draining back to the engine, avoiding the potential of causing major engine damage. The special bottom inlet extends into the bottom of the scrubber to avoid any water running into the inlet duct. Because of its design harmonics, the scrubber is able to eliminate/replace the need for an engine silencer. The Belco Marine Scrubber can operate in three different modes: open loop, closed loop or dry. In open loop operation, the scrubber uses only seawater on once through pass for scrubbing. The open loop scrubber can only be used where there is enough alkalinity in the seawater. In closed loop operation, the scrubber liquid is not used on a once through basis but is recycled and 'dosed' with an alkaline reagent such as caustic in order to reduce the amount of SO x in the exhaust gas to meet the required outlet. The closed loop system is used where there is not significant alkalinity in the water for open loop scrubbing, such as in fresh water lakes, rivers and areas in the Baltic (or any other body of salt water which has low alkalinity) or where there are regulations or other reasons for not being able to discharge the scrubber effluent (often referred to as wash water). In dry mode, hot exhaust gases exit the ship through the scrubber vessel. The scrubber is off and there is no emission control taking place. Dry mode also allows the Belco Marine Scrubber to be installed without a bypass. A ship would typically operate in dry mode when travelling outside of an ECA. A scrubbing system can be provided which can operate in any of the three modes, and therefore in any maritime environment. This system is referred to as the BELCO MS Hybrid and contains all of the equipment and instrumentation for either mode of scrubbing or run dry. Conclusion It is unlikely that investment in refining processes needed to meet the ultra low sulfur marine fuel demands imposed by MARPOL Annex VI regulations will be made. For ships to take advantage of available fuel regardless of sulfur content and still meet the regulations, an exhaust gas cleaning system, or scrubber, is an increasingly popular option. Based on the amount of time a ship spends in an ECA, current fuel price differentials, amount of fuel consumed, scrubber costs, and other variables, a ship outfitted with a scrubber can have a payback period of l.5 to 3 years. With the fuel price differentials increasing, the payback period can even be shorter. Source: Hydrocarbon engineering August 2014