【作者】

Munekatsu FURUGEN,Tadashi MAKINO

【摘要】

论文已在中国上海举行的第27届CIMAC大会上发表。论文的版权归CIMAC所有。The harmful exhaust gas emissions from marine diesel engines are NOx, SOx, and particu-late matter(PM). For NOx and SOx, the IMO Tier llregulation went into effect in January 2011, and the regulation is strengthened in the Tier lill. On the other hand, for PM, an action to reduce the sulfur content of fuel oil is adopted for the nonce. Because marine diesel oil(MDO) and heavy fuel oil(HFO) are used as the fuel in the marine diesel engines, large amount of PM is emitted. However, for marine diesel engine,a practical use of the diesel particulate filter(DPF) is not realized at present. The authors newly developed an Electro-static Cyclone DPF to reduce PM emission in dieselexhaust. This DPF consists of an electrostatic pre-cipitator(ESP) and a cyclone precipitator(Cyclone).The ESP is arranged in the upstream position, and the Cyclone is arranged in the downstream position.A mechanism of the PM collection in the Electrostatic Cyclone DPF is as follows: The EPS can collect fine particles, and the Cyclone can collect large agglomerated particles. When the thickness of deposited PM which is collected on the collecting plate of ESP becomes excessive, the deposited PM falls automatically away from the collecting plate. And then the fallen deposited PM is easily collected into the dust box of Cyclone. An advantage of the Electrostatic Cyclone DPF is in a structure without the PM clogging both in the ESP and the Cyclone; therefore this DPF is maintenance free equipment fundamentally. Experiments: The PM collection test with the DPF was investigatedby using two types of marine diesel engines,i.e., the low speed two-stroke engine(3UEC33LSII-ECO,1275kW,162 rpm) and the medium speed four-stroke engine(MU323DGSC,257 kW,420 rpm). Two types of fuels, MDO with a sulfur content of 0.07 % and HFO with a sulfur content of 2.2 %, were used for the tests.The DPF was installed in the exhaust line of the engines, and PM mass concentration and PM particle size distribution were measured. PM mass concentration was measured with the dilution tunnel system, and PM particle size distribution was measured with the Scanning mobility particle sizer(SMPS). Results:(1)The Electrostatic Cyclone DPF can reduce PM emission by greater than 90 %. The DPF has high collection efficiency not only for soot but also for sulfate and soluble organic fraction(SOF) in PM.(2) The PM collection efficiency for HFO was higher than that for MDO; therefore it was confirmed that the DPF is applicable to marine diesel engines operated with HFO.(3)The majority of the PM particle has a diameter of less than 500nm, and the PM collection efficiency for par-ticles smaller than 100nm, which are especially harmful for health, is greater than 95 %.(4) As the Electrostatic cyclone DPF shows high collection efficiency, an exhaust gas processing system which can reduce PM, SO, and NO, will be realized by application ofthe DPF. The proposed exhaust gas processing sys-tem consists of the DPF, the scrubber and the EGR system. The scrubber is arranged in the downstreamposition of the DPF. The exhaust gas from which PM and SOx was removed through the DPF and the scrubber is used as EGR gas. As a result, PM, SO, and NO, can be reduced by this system. Because only SOx and NOx are included in the exhaust gas passingthrough the scrubber, the proposed system has an advantage that the wastewater disposal in the scrubber is easy. The authors believe that the proposed exhaust gas processing system is appropriate for the marine diesel engines

【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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