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Cimac Congress | Shanghai 2013 concise formulation and flexibility had to be found. This paper will present the methodology and highlights (based on simulation, test results and new components design) towards a complex engine power and efficiency upgrade development project based on an already existing engine platform. Ported fuel injection for maritime gas engines Gerhard Ranegger, Hoerbiger Ventilwerke, Austria Gerhard Kogler, Hoerbiger Ventilwerke, Austria Peter Steinrueck, Hoerbiger Kompressortechnik Holding, Austria Future emission limits for maritime engines call for dramatic reduction of particle matter, NOx and SOx in emission regulated areas. With the expected demand for ultra clean propulsion systems, the engine industry has started the development of gas-fuelled engines. Gas-fuelled ferries are operated successfully in Norway, tug boats will follow soon. These ships are propelled by spark ignited engines. For many more years, dual-fuel and tri-fuel engines have been in service, powering LNG ships and offshore oil and gas rigs. Most of these engines are using LNG that is used in bone dry condition. The absence of any oil mist or oil vapour implies special challenges for the equipment in contact with this gas, in particular the solenoid valves that are used for ported fuel injection suffer from excessive wear reducing engine service intervals and causing reliability problems. Compliance with stringent protection systems and safety regulations – like mandatory double-wall sealing of the gas piping system – impose other challenges for the design of such ported fuel valves. The authors present a novel design of ported fuel injection valves for large-bore engines, which incorporates design elements successfully deployed for ported fuel valves for cryogenic hydrogen-fuelled internal combustion engines. By use of special combination of material for the sealing elements to avoid cold welding, which leads to increased leakage, a longer life time can be achieved. The new design is prepared for leak detection systems and incorporates unique solutions with respect to the electrical connections and wiring to comply with existing regulations. Stable operation of the gas-fuelled engine requires high repeatability of valve operation and low valve to valve variances. A low-lift concept derived from Hoerbiger experience in compressor valve design reduces response time for more accurate gas metering. In conjunction with the need to operate the fuel valves in a large operating range, the valves have to work under elevated differential pressure exhibiting only insignificant leakage. In applications with a two-stage turbocharger and increasing gas supply pressure, the leakage of the PFI valves become even more important. In this paper a method will be presented how to fulfil this requirement by a nonpressure balanced concept and reduce closing time at the same way in order to avoid post injections or residual gas in the air manifold. The electromechanical design of the presented solution copes with these challenges, thus offering the engine designer new means to realise efficient and reliable maritime engines complying with tomorrow’s emission regulations. Tuesday May 14th / 15:30 – 17:00 Environment, Fuel and Combustion Diesel Engines – NOx Reduction by O 2 Reduction Room C Reduction of NOx emission by 80% using the newly developed system with a polymer membrane in marine diesel engines Kazuyuki Maeda, National Fisheries University, Japan Akihiko Azetsu, Tokai University, Japan Hirokazu Ohno, Asahi Kasei Chemicals Corporation, Japan Atsushi Shimizu, Asahi Kasei Chemicals Corporation, Japan Tomohiro Niihama, Asahi Kasei Chemicals Corporation, Japan Masahiro Tsukamoto, Asahi Kasei Engineering Corporation, Japan Dai Yamanishi, National Fisheries University, Japan By 2016, under the IMO Tier III rules, NOx emission from ships sailing in ECAs should be reduced by more than 80% relative to the IMO Tier I levels. A selective catalytic reduction (SCR) system, a water treatment (such as emulsification fuel) system and an exhaust gas recirculation (EGR) system are proposed as concrete methods. Recently, the nitrogen-enrichment humidification membrane (NHM) system developed by Asahi Kasei Chemicals Corporation has received much attention. This device reduces NOx emission by decreasing the oxygen density in the suction air using a special membrane while increasing the moisture content in the suction air. Because this device is installed on the suction air side, it will not be affected by trends on marine fuel sulphur content regulations or supply trends of marine fuel in the future. Moreover, because the operation materials are water and air, this system is environmentally friendly. In this study, in order to reduce NOx emission from marine diesel engines, the following experiments were carried out. At first, to explore the spray combustion characteristics of diesel fuel under very low oxygen density ambient condition, a high-temperature and high-pressure combustion vessel with two observation windows was observed. Second, the NHM system was connected to the suction line of a high-speed marine diesel engine and a low-speed two-stroke single cylinder engine, and the effects of the oxygen density and the moisture content in the suction air on NOx emission were investigated. The NHM system with a polymer membrane that has selective permeability with respect to oxygen and water vapour is composed of an oxygen reduction system that can freely establish the oxygen density and a humidifying system that can freely establish the moisture content in the suction air. The following experiments were carried out: • Visualisation of combustion: high-temperature and high-pressure combustion engine with two observation windows was photographed by a high-speed colour video camera through one of the windows. • Effect of the oxygen density: Humidity of the suction air was adjusted to 0% using a dryer. The oxygen density of the suction air was then reduced from 21 to 16.2% using the oxygen reduction system. • Effect of the moisture content: The moisture content in the suction air was increased from 0 to 16% using the humidifying system. • Combination effect of the oxygen density and the moisture content: The density of oxygen was set to 21, 20, 19 and 18% using the oxygen reduction system and the moisture content was then increased for each density. Results clarified that the IMO standards can be satisfied based on the following conditions: • The flame temperature becomes lower as the decrease of oxygen density mainly due to the dilution effect and as the increase of CO 2 mixing due to the increase of specific heat, and results in the low NOx emission. • NOx emission decreased as the oxygen density decreased for each load factor, and thus the restriction on NOx emission set by the IMO standards can be satisfied simply by setting the oxygen density at less than 17%. • NOx emission decreased because the oxygen density decreased for increases in the moisture content, and thus the IMO standards can be satisfied simply by adjusting the humidity of the suction air at more than 16 mol.%. • Taking into account the operating conditions of the engine, NOx emission can be effectively reduced by decreasing the oxygen density as well as increasing the humidity of the suction simultaneously. 40 SPECIAL Schiff&Hafen | Ship&Offshore | May 2013
Monday, May 13th Tuesday, May 14th Wednesday, May 15th Thursday, May 16th Development of integrated EGR system for twostroke diesel engines Johan Kaltoft, MAN Diesel & Turbo SE, Denmark Mikkel Preem, MAN Diesel & Turbo SE, Denmark The IMO Tier III NOx regulations will come into force in 2016. This means that NOx emissions from large two-stroke diesel engines must not exceed a cycle value of 3.4 g/kWh, and NOx emissions must not exceed 5.1 g/kWh on the individual load points of the load cycle. To comply with the Tier III requirements, MAN Diesel & Turbo is involved in a targeted and continuous development of exhaust gas recirculation (EGR) for NOx reduction on low-speed two-stroke diesel engines. The latest investigations on MAN Diesel & Turbo’s research engine in Copenhagen regarding the next generation of EGR system, scrubber performance, high speed and high efficiency EGR blower and water treatment system will be covered. The following topics will be described: confirmation test of integrated EGR system design, sulphur and particle reduction ratios in the EGR scrubber, blower performance and water treatment system functionality and requirements. The first MAN B&W Tier III EGR diesel engine has been successfully delivered for a 4,500 TEU container vessel. The following topics regarding the first Tier III EGR two-stroke diesel engine will be covered: engine integrated design with multiple turbochargers, EGR auxiliary equipment, installation aspects and shop test performance results. The development process of the 6S80ME-C9.2 EGR engine has resulted in a finalised EGR engine design, and implementation on other engine sizes is in progress. Newly developed combined EGR & WEF system to comply with IMO NOx Regulation Tier III for twostroke diesel engine Masanori Higashida, Kawasaki Heavy Industries, Ltd, Japan Takuroh Nakamura, Kawasaki Heavy Industries, Ltd, Japan Ikumi Onishi, Kawasaki Heavy Industries, Ltd, Japan Katsuhiro Yoshizawa, Kawasaki Heavy Industries, Ltd, Japan Hirotaka Takata, Kawasaki Heavy Industries, Ltd, Japan Takamichi Hosono, Kawasaki Heavy Industries, Ltd, Japan The IMO NOx emission regulation Tier III will come into force from 2016 and requires marine two-stroke diesel engines to reduce their emission below a cycle value of 3.4 g/kWh in ECAs. To cope with this regulation, the combined EGR (exhaust gas recirculation)& WEF (water emulsified fuel) system, aiming at effective NOx reduction with the minimum penalty in fuel oil consumption, has been newly developed and provided for the fullscaled test engine Kawasaki-MAN B&W 2S50ME-C. The applied EGR is a high-pressured EGR, featuring compactness in components. A Turbocharger cut-out system and a VT (variable turbine nozzle area) turbocharger are incorporated in the EGR system, which enables it to reduce NOx with only a minimal impact on fuel oil consumption, and to switch on/off depending on the sea area. A wet scrubber is also incorporated in the EGR system to remove SOx and PM in the recirculating gas, which prevents corrosion and contamination in the scavenging air system during EGR. Detection and control methods for water carry-over have been newly established and tested. The water treatment system is one of the most important systems for EGR and has been developed to remove PM in the washing water out of the scrubber. A special compact settling tank with unique ditches has been developed based on the sewerage treatment technologies and secures the efficient removal of PM. This paper describes 1) the characteristics of the EGR system, such as relations between EGR ratio and NOx emission, EGR ratio and fuel oil consumption, etc. both on newly developed EGR system with turbocharger cut-out system and VT and on conventional EGR system without them; 2) the performance of the scrubber including water carry-over; 3) the capability of the water treatment system; 4) the result of the combined EGR & WEF system measured on the test engine is reported in comparison with using EGR alone. In addition to the test results by the test engine, this paper describes the outline of our original ’package type EGR system’ for onboard tests. The package EGR system that major components of EGR are equipped on the main engine is introduced to facilitate the installation of the system on the ship. On the other hand, WEF technique is preceding EGR and now provided for long-term operation in order to accumulate experiences in service field. The latest condition is reported additionally. Demonstration of emission control technology for IMO NOx Tier III Yoshiyasu Murayama, Niigata Power Systems Co, Ltd, Japan Tetsuya Tagai, Niigata Power Systems Co, Ltd, Japan Takahisa Mimura, Niigata Power Systems Co, Ltd, Japan Satoru Goto, Niigata Power Systems Co, Ltd, Japan In order to meet stringent emission standards for marine engines, we at Niigata have been continuing the development of low emission technology for a long period. Three emission control technologies – exhaust gas aftertreatment, alternative fuels and combustion improvement – were developed to meet upcoming IMO NOx regulations (Tier III), and these countermeasures can be selected due to required output, applications and ship design. The first measure is the exhaust gas aftertreatment by using selective catalytic reduction (SCR). Niigata has started to provide the marine SCR system from the middle of the 1990s, and has gained some good experience about performance design and operation. The key issue for marine SCR system is the installation size and control technology that handles suitable amount of reducing agent for each engine loads. Onboard tests were carried out to verify that performance of our newly developed SCR system fulfils a required specification for Tier III. The required injection amount of reducing agent is determined by using several ordinary sensors on the engine. In addition, the effect of atmospheric conditions on NOx emission is also considered. Therefore, the developed SCR system is useful not only for inland but also oceangoing vessels. The test system was operated to maintain 80% NOx reduction rate from Tier I condition through the onboard test, and it was successfully controlled without ammonia slip. The second measure is the usage of alternative fuels. To date, gas engines were employed for land-based power generation and cogeneration, several types of gas engine – dual-fuel, spark ignition and micro pilot engine – are reliable. Due to lower adiabatic flame temperature with leanburn combustion, the NOx emission is extremely low and the emission level is a tenth of that of diesel engines. Consequently, gas engines have a potential to comply with Tier III without any further additions. The third measure to reduce NOx emissions is the improvement of the combustion for diesel engines. The Miller cycle is an essential combustion technology to decrease NOx emission due to lower incylinder gas temperature and to improve cycle efficiency. This technology was employed on diesel engines to meet Tier II; however, the magnitude of the effect is enhanced to achieve remarkable NOx emission reduction in this study. Since the extremely high boost pressure is required when a stronger Miller cycle is applied, the two-stage turbocharging system was employed. The obtained NOx reduction from Tier I condition was reached up to 50% due to double improvement effect regarding the turbocharger efficiency and the cycle efficiency. The EGR, which is well May 2013 | Schiff&Hafen | Ship&Offshore SPECIAL 41
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Page 5 and 6: The Future is Clear ME-GI dual fuel
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