【作者】

Kazuyuki Maeda，Akihiko AZETSU

【摘要】

论文已在中国上海举行的2013年CIMAC大会上发表。论文的版权归CIMAC所有。 By 2016, under the IMO Tier III rules,NO x emission from ships sailing in the Emission Control Area (ECA) 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 (Japan) 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 sulfur 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 NO x emission from marine diesel engines, the following experiments were carried out. At the first, to explore the spray combustion characteristics of diesel fuel under very low oxygen density ambient condition, high temperature and high pressure combustion vessel with two observation windows was observed. And the 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 NO x emission were investigated. The NHM system with a polymer membrane that has selective permeability with respect to oxygen and water vapor 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. (1) Visualization of combustion: high temperature and high pressure combustion vessel with two observation windows was photographed by a high speed color video camera through one of the windows. (2) 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’. (3) Effect of the moisture content: The moisture content in the suction air was increased from 0 to 16 % using the ’humidifying system’. (4) 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. (1) The flame temperature becomes lower as the decrease of oxygen density mainly due to the dilution effect and as the increase of CO2 mixing due to the increase of specific heat, and results in the low NOx emission. (2) 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%. (3) 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.%. (4) 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.

【会议名称】

第27届CIMAC会议

【会议地点】

上海

【下载次数】

1

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