Absorption of SO2 by Basic Oxygen Furnace Slag
|關鍵字:||轉爐石;二氧化硫;吸收劑;煙道氣除硫法;鈣利用率;二氧化硫捕捉率;BOF;SO2;sorbent;FGD;Ca utilization;SC||公開日期:||2005||摘要:||轉爐石為轉爐煉鋼的廢棄物，其組成中CaO約佔40 wt.%。本研究探討利用轉爐石吸收二氧化硫的可行性。轉爐石經過研磨與篩分之後，分別添加氫氧化鈣、廢玻璃粉末，以及鹽酸溶液，經過漿化和乾燥，製備出吸收劑，再以微分固定床反應器，在模擬乾式煙道氣除硫程序的條件下（60℃、70%RH、1000 ppm SO2），量測吸收劑對二氧化硫的反應性。
轉爐石與氫氧化鈣在漿化過程中（水/固比10/1）並未反應生成高比表面積的水合產物，所得吸收劑的比表面積，與重量配比(100/0-0/100)、漿化溫度(25-95℃)、漿化時間(0.42-32 hr)並無顯著的關係，約在11-19 m2/g之間。轉爐石/廢玻璃吸收劑(50/50)則在漿化過程中生成高比表面積的矽酸鈣水合物。轉爐石添加鹽酸可將部分鈣轉化為具潮解性的氯化鈣。研磨後的轉爐石原料，其反應一小時的鈣利用率可達0.14，但低於氫氧化鈣的鈣利用率(0.19)。轉爐石/氫氧化鈣吸收劑的鈣利用率在重量配比小於50/50時，高於氫氧化鈣，以40/60時為最佳，達0.31；重量配比為10/90時的二氧化硫捕捉率將最佳，約0.22 g SO2/g sorbent，略高於配比為40/60的吸收劑(0.21 g SO2/g sorbent)。轉爐石與鹽酸在室溫下漿化所得到的吸收劑，其鈣利用率隨鹽酸添加量變化，在0.1 mol HCl/100g BOF3時達到最大值0.35，此值略高於轉爐石/氫氧化鈣吸收劑的最佳鈣利用率；其二氧化硫捕捉率則為0.14 g SO2/g sorbent，低於轉爐石/氫氧化鈣吸收劑之最佳二氧化硫捕捉率。
Basic oxygen furnace slag (BOF slag), which contains about 40 wt.% CaO, is a waste in the steelmaking process. The feasibility of utilizing BOF slag for SO2 absorption was studied in this work. Ground BOF slag together with hydrated lime (HL), or recycled glass powder (FG3), or HCl solution were slurried and dried to obtain sorbents. The sorbents were reacted with SO2 in a differential fixed bed reactor under the conditions simulating the dry flue gas desulfurization (dry FGD) process (60℃, 70%RH, and 1000 ppm SO2) to measure their reactivities toward SO2 for sorbents were measured. No hydration products with high specific surface area were produced during the process of slurrying BOF3 with HL (L/S=10/1). The sorbent specific surface areas (about 11-19 m2/g) was not closely correlated with BOF3/HL weight ratio (100/0-0/100), slurrying temperatures (25-95℃), and slurrying time (0.42-32 hr). However, calcium silica hydrates with high specific surface area were formed for BOF3/FG3 sorbents (50/50) during the slurrying process. Calcium content of BOF was partially converted to deliquescent CaCl2 by the addition of HCl. The one hour utilization of Ca for ground raw BOF3 was 0.14, lower than that of HL (0.19). The BOF3/HL sorbents had higher Ca utilization than HL when the weight ratio was smaller than 50/50, and the sorbent with a 40/60 ratio had the maximum value of 0.31. The sorbent with a 10/90 ratio had the maximum SO2 capture, 0.22 g SO2/g sorbent, which was slightly higher than that for the sorbent with a 40/60 ratio, 0.21 g SO2/g sorbent. The Ca utilization for the sorbents prepared by slurrying BOF3 with HCl solution at room temperature varied as the added amount of HCl changed, and reached a maximum value of 0.35 at 0.1 mol HCl/100g BOF3; the SO2 capture for this sorbent, 0.14 g SO2/g sorbent, however, was lower than the best SO2 capture for BOF3/HL sorbents.
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