L.A. Maritime describes the operation of Aquametro Fuel-Switching Devices L.A. Maritime is pleased to announce a new cooperation with Aquametro AG of Switzerland. As of September 1, 2015, L.A. Maritime is the exclusive agent for both sales and service of Aquametro Fuel- Switching products in North America. Aquametro describes the operation of their devices as follows: Fuel Management - reliable switching of fuels before entering ECA areas Since 1 January 2015, the provisions of IMO MARPOL Annex VI, according to which a seagoing vessel reaching a designated ECA area may only use fuels with a sulfur content of <0.1% apply. This means that a seagoing vessel with heavy fuel oil (HFO) is operating without a scrubber installed must be switched to a low sulfur distillate (MDO / MGO) in time before entering the ECA zone. For the switchover from heavy oil to fuels with <0.1% sulfur content requires special requirements on the fuel system and the fuel preparation according to the different fuel qualities. The ship operators have to realize the timely and technically secure conversion of fuels. The diesel engines are basically designed for one type of fuel and this is out of cost reasons usually for HFO operation. The different fuel qualities and their physical properties make different demands on fuel processing and engine components. From the switchover processes between heavy fuel oil to low-sulfur distillates arise due to the different temperature and viscosity behavior of both fuels, high thermal component stresses acting differently in the fuel supply, the fuel circulation and in injection system. Rapid changes in the fuel temperatures lead to different thermal expansions of significant components particularly in circulation and injection system of the diesel engine, which is causative faults and failures, for example, the injection pump. In addition, high temperatures during switchover lead to a reduction in viscosity of the distillate fuel, which can subsequently lead to increased leakage at fittings and seals to the total pressure drop in the injection system. Depending on the requirements of engine manufacturers a maximum permissible temperature gradient of 2-3 C / minute has to be controlled. With the failure of the fuel system and the total failure of the engine system goes hand in hand, which in turn results in the loss of control of the ship by itself. ECA areas are coastal areas with increased traffic. Failures of the ship propulsion system lead to danger of the ship, crew as well as the regional vessel traffic and the environment. They are thus subject of course to increased scrutiny by the port and coastal states. In fuel supply systems, the low viscosity of the distillate cause leakages, which may have an increased fire hazard in case of proximity to hot components (hot spots). By fuel industry intensive efforts are being made to the MARPOL requirements with cost-effective new fuels to meet. Such hybrid fuel having a higher viscosity than distillates can reduce thermal problems in the fuel system described.
Fuel treatment The basis for the production of heavy oils for shipping incurred in refining residue (bottom product). The application of catalytic and thermal cracking process resulting incompatibility problems when mixing different fuel qualities. The starting point for today's heavy oils are residual oils from the various cracking processes whose characteristics may vary depending on the refinery / oil company and employed crude. Problems in terms of quality and incompatibility of bunkered fuel and the mixture of different fuel batches, also within the same types of fuel, can lead to serious system disorders such as excessive sludge formation in the fuel preparation and ultimately lead to system failures. The fuel preparation is to be tuned according to the fuels used and the engine requirements. To detect possible incompatibilities in the fuel the crew uses as fast-track procedure compatibility tests to compare the different fuels or fuel batches available onboard with each other. Figure 1. Test Kit - Compatibility of Fuels The use of a fuel homogenizer offers the possibility to avoid Sludge - or Aspalthen clustering. The intervals between cleaning the filter can be significantly extended. The inclusion in an exemplary fuel system is shown in FIG. 6. Fuel Monitoring / Management Classification societies as well as engine manufacturers dictate guidelines and recommendations for the switching process between two types of fuel, they have become increasingly no longer with manual intervention of the crew and the resulting operating errors. A safer, more efficient and environmentally friendly operation of the engines requires an automated fuel management on board to monitor the full operational and functional capacity of the fuel system, as it currently does not appear in ship operation. For the switching process the engine manufacturer is recommending (dictate?), a corresponding fuel management. Fig. 3 shows the preset function sequence between distillate - diesel oil (DO) - and heavy fuel oil (HFO) with appropriate parameter limits.
Figure 2. Fuel Homogenizer principal view Figure 3. Default MAN switching processes between HFO and DO/MAN Diesel Fact 1/2015 Fig. 4: Function sequence changeover process from HFO to DO traditional and automated with Aquametro DIESEL SWITCH
Figure 4: Function sequence changeover process from HFO to DO traditional and automated with Aquametro DIESEL SWITCH For example, in existing regulatory processes for switching from HFO specified in DO subsequent measures require some manual intervention. 1. With an increase in the viscosity of the fuel injection, the temperature level is lowered in order to decrease the temperature difference during switching. This reduces potential thermal stress of the components in the fuel system. 2. With the reduction of engine power the fuel volume - or fuel mass flow shall be reduced. This causes a delay of the mixing / switching process in the fuel circulation system, enabling the control systems a slower parameter adjustment. Here, it is assumed that the switching between the two types of fuel in the fuel delivery is performed in one step, that means it is not regulated. 3. Turning off the trace heating and fuel preheating causes a reduction in the heat input into the fuel system while distillate / DO - operation 4. By connecting a fuel cooler in the fuel system excess heat, for example, residual amounts of heat during switching process or the heat input of the circulation and injection pump is removed. The steps 2 and 4 ensures that the minimum permissible injection viscosity of the engine manufacturer can be adhered to. The measures are linked to a fixed time regimes that are created by the ship's operator, together with the classification society and processed by the crew according to a schedule before reaching the ECA zones. The predetermined steps of switching between HFO and low sulfur distillate are geared to predetermined load points and timings, which due to a lack of automated control algorithms are based on timing schedules that ensure timely switching the fuel before reaching the ECA zones. This results in some very long changeover.
The use of a Fuel monitoring / management system, as the Aquametro DIESEL SWITCH system, with automated, secure switching from HFO to distillates, offers the possibility to realize a secure, yet fast switching operation with knowledge and monitoring of system parameters describing the fuel system. A reduction of the engine power is not required. It can in relation to the mixing ratio of the fuel during the changeover and the specific operating state switch fuel coolers and HFO preheater on/off or controlled in time. Even in the event fuel incompatibilities the system can optionally start or stop the homogenizer for sludge reduction. Figure 5. Fuel Management - Aquametro DIESEL Switch system Figure. 5: Fuel Management - Aquametro DIESEL SWITCH system / www.aquametro.com The operational management of the fuel system via a Fuel Monitoring / Management is thus automatically and ensures a safe switching operation in which all Specifications from the engine manufacturers are adhered to. Compliance with time schedules, as they are drawn up by the classification, are not necessary. With a qualified Fuel Management, for example, the Aquametro DIESEL SWITCH, subsequent activities may be fully automated for switching from HFO to low-sulfur distillate fuels or hybrid. Manual intervention in existing regulatory processes are not required, which increases the operational reliability considerably. 1. The automated progressive fuel switching by Aquametro DIESEL SWTICH effected by temperature control of the mixing fuel during the switching process. 2. Knowing the fuel composition at any time of the changeover process allows downstream system components in the fuel system to switch on or off predictively this may be:. On/off switching of the heat tracing or HFO preheating. On/off switching of the fuel cooler. Control of the cooling capacity of the fuel cooler on the cooling water inlet. On/off switching of a homogenizer to reduce sludge formation before injection engine - Aquametro Homogenizer The switching process successfully completed at the DIESEL SWITCH system is documented with the status information "SWITCH OFF". With the status message "FUEL ON ENGINE" the entire switching process is concluded with availability of the second type of fuel to the engine after evaluating the permanently measured temperature profile at the engine inlet. As a complete changeover example of
HFO to distillate resulting from the period between the start of the switching process "CHANGE OVER PROCESS ON" and the status message "FUEL ON ENGINE". In addition to the configurable setting parameters to the specific fuel system, the switching time is therefore solely dependent upon the engine load and thus of the fuel volume flow. Signified alarms and limits can be parameterized and monitored. Moreover, alongside the fuel viscosity and 2 additional freely configurable measurement signals (eg. Fuel consumption, differential pressures).optionally the GPS protocol can be integrated and thus be assigned any status message of the exact ship's position and time. All status information, System Settings and alarm message can be exported as a data file. Figure 6. Integration - Fuel Monitoring / Management & homogenizer into a fuel system www.aquametro.com