抄録
Long-term exposures to diesel particulate matter (DPM) emissions are linked to increasing adverse human health effects due to the potential association of DPM with carcinogenicity. Current DPM emission regulations are based solely upon total mass concentration, albeit it is the sub micrometer particles that are highly respirable and the most detrimental to human health. The electrostatic scrubber efficiency was measured under various engine loads. In addition, DPM collection efficiency was found to be directly related to exhaust gas capacity, the charge to mass of the water, water electrical properties and water spraying performance. The effect of the scrubber on the collection of DPM was investigated experimentally. The fine DPM which have diameter between 0.1 and 2.5 microns are removed at very high efficiency by highly electrical charging to the water droplets and DPM in opposite polarity. Simultaneously, all soluble acid and caustic gases are removed at the same levels as those of conventional scrubbers. Even though the primary mechanisms of scrubbing of DPM are known, the exact mechanism is not understood yet. Prediction of DPM collection efficiency is very important to evaluate pollution control of equipment. Hence verification of the overall efficiency achieved by any spray scrubbing system based on theoretical models is essential. In this paper an attempt has been made to theoretically predict the efficiency for an electrostatic water spraying scrubber. Results indicate that a maximum of overall collection efficiencies for fine DPM from marine diesel engine over 97% of all particle sizes and it allowed decreasing the water consumption up to about 4〜5 times. A comparison of the experimental and theoretical efficiencies has been made and systematically analyzed.
