逸散性揚塵微粒於物料堆置區之防制研究

鋼鐵業原物料堆置為重要的逸散來源之一，原物料在取（卸）料的過程中，容易受到擾動而產生揚塵逸散，這些微粒逸散不僅會影響廠區內的空氣品質，也影響附近居民之健康，故應該設置有效之防制設施以抑制揚塵逸散。為了解物料堆置區內之防制設施是否有效抑制揚塵，以及堆置區周界PM2.5之化學成分，本研究於鋼鐵廠內料堆堆置區內以高量採樣器及落塵桶採集TSP及落塵，以驗證整個廠區之防制效率，最後利用PQ200及高量採樣器採集PM2.5及TSP，以了解懸浮微粒之物理及化學成分分析，項目包含TSP及PM2.5質量濃度、落塵量、PM2.5之水溶性離子成分及金屬元素成分。本研究結果顯示，料堆堆置場內物料為鐵礦TSP濃度範圍為53～75 µg/Nm3，物料為煤礦TSP濃度範圍則為244～347 µg/Nm3 煤礦的逸散程度比鐵礦嚴重，故選擇煤礦作為驗證防制設施之物料；濕季時在堆置場內以使用灑水設施下，上下風處相對削減率（56 ％）為最佳；乾季時則以防塵網+化學穩定劑下，上下風處相對削減率（82 ％）為最佳。防塵網驗證結果顯示，1小時TSP防塵網完工前後平均削減率以 90 ％為最佳，內外側測點平均濃度分別為 1390及134±3 µg/Nm3；24小時TSP防塵網整體完工前防塵網平均削減率，夏季和秋季皆為60 ％，完工後防塵網內外側測點平均削減率，冬季和春季分別為50 ％及89 ％，平均削減率以春季時（89 ％）為最高，當防塵網內側濃度越高時，越能凸顯出防塵網之防制效率；完工前平均削減量為24.58 ton/km2/month，完工後平均削減量為33.44 ton/km2/month，雖然完工後平均削減率略低於完工前，但平均削減量高於完工前8.86 ton/km2/month。料堆堆置場周界兩次採樣PM2.5及TSP濃度分別為31.10±0.63 μg/m3、178±45 μg/m3及31.55±2.42 μg/m3、293±128 μg/m3，PM2.5/TSP比值為0.14～0.27及0.07～0.22，料堆堆置場周界PM2.5化學成分分析中，水溶性離子主要皆以SO42-、NO3-、NH4+三種衍生性氣膠為主，佔水溶性離子比例為85～90 ％及90～95 ％；金屬元素皆以Na、K、Mn、Fe、Zn及Si為主，其微粒上之K可能來來自石料，而Fe可能來自煤礦和鐵礦。

關鍵字

料堆堆置場；防制設施；總懸浮微粒（TSP）；落塵； PM2.5

並列摘要

Material stacking is one of the important fugitive sources in steel industry. In the process of taking (unloading) materials, the materials are easily disturbed to generate fugitive dust. This fugitive suspended particulate matters will not only deteriorated the air quality in the plant area, but also affected the health of nearby residents. Therefore, should be set up control devices to control suspended particulate matters emissions.In order to understand whether the control devices in the material stacking area effectively control suspended particulate matters emissions, and the chemical composition of PM2.5 around the material stacking area. This study selected a steel plant in Taiwan. Under various control devices and collected TSP with high-volume samplers in the material stacking area. And collected TSP and dust fall, in order to verify the control efficiency in the whole plant area. Finally, collected TSP and PM2.5 with high-volume samplers and PQ200 to understand the physicochemical properties of PM, including mass concentration, dustfall concentration, water-soluble ionic species, and metallic elements, were further analyzed. The results of this study indicate that the material in the stacking area is 50-75 μg/Nm3 of TSP in iron ore, and 244-347 μg/Nm3 in coal of TSP. The coal has a greater degree of fugitive than iron ore. Therefore, the coal selected as the material to calculate the control efficiency of various control devices. Under the control devices in the material stacking area：In the wet season, the relative reduction rate (56%) is best when using the water-sprinkling; in the dry season, the relative reduction rate (82%) is the best when useing the dustproof grid + chemical stabilizers. The results of 1 hour TSP verificationt control efficiency of the dustproof grid showed that the average reduction rate of 90 % is the best, and the average concentration of the inner and outer points were 1390 and 134±3 μg/Nm3 . The average reduction rate of the dustproof grid before the completion of the 24-hour TSP dustproof grid was 60% in summer and autumn. The average reduction rate of the dustproof grid after completion were 50% and 89% in winter and spring, and the average reduction rate was the best in spring. When the concentration inside the dustproof grid was higher, the prevention efficiency of the dustproof can be highlighted. The average reduction before completion was 24.58 ton/km2/month, the average reduction after completion was 33.44 ton/km2/month. In two samplings of around the material stacking area, fist sampling PM2.5 and TSP concentrations were 31.10±0.63 μg/m3 and 178±45 μg/m3, the second sampling were 31.55±2.42 μg/m3 and 293±128 μg/m3, and the PM2.5/TSP ratio is 0.14～0.27 and 0.07～0.22 Chemical analysis of PM2.5 results showed that the most abundant water-soluble ionic species were secondary aerosols （SO42-, NO3-, and NH4+）, accounting for 85-90 % and 90-95 % of the total water-soluble ions. Na, K, Mn, Fe, Zn and Si were the major metallic elements of this study. The source of K pollution may come from stone, and Fe may come from coal mines and iron ore.