高爐爐石/氫氧化鈣與轉爐爐石/氫氧化鈣吸收劑在高溫下與二氧化硫反應之研究

Iron Blast Furnace Slag/Ca(OH)2 and Basic Oxygen Furnace Slag/Ca(OH)2 Sorbents for SO2 Removal at High Temperatures

廖坤祥(Kun-Hsiang Liao)

指導教授 ： 施信民

國立臺灣大學/工學院/化學工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.02824

摘要

本研究以微分固定床反應器探討高爐爐石(BFS)/氫氧化鈣(HL)與轉爐爐石(BOF)/氫氧化鈣(HL)吸收劑在高溫下(750℃-950℃)與二氧化硫之反應。吸收劑漿化過與否，均隨著溫度升高而提高其ㄧ小時鈣利用率和SO2捕捉率。漿化過的BFS/HL吸收劑，主要由於產生了矽酸鈣水合物，使得其反應性較未漿化過者更好。BFS/HL吸收劑的反應性在重量配比10/90最佳，之後隨著配比增大而遞減。低配比時BFS顆粒有助於HL顆粒的分散，所以吸收劑的反應性會提升；而高配比時則因BFS顆粒的反應性低和在750oC以上時會造成吸收劑顆粒之間的黏結，所以吸收劑的反應性會降低。漿化過之BOF/HL吸收劑因晶體較小，混合較好，其反應性較未漿化過者稍佳。BOF/HL吸收劑的反應性在重量配比10/90時最佳，之後隨著重量配比增加而緩慢下降。BOF/HL吸收劑因BOF不會燒結，且氧化鐵含量高可以催化硫酸化反應，故其反應性較BFS/HL吸收劑為佳。與先前吸收劑低溫反應結果比較，發現BFS/HL吸收劑在高溫時反應性較佳，配比小於30/70的吸收劑特別顯著；BOF/HL吸收劑在各配比皆為高溫時反應性顯著較佳。與先前飛灰(FA)/HL高溫反應的結果比較，發現三種吸收劑高溫SO2捕捉率的高低次序為BOF/HL＞BFS/HL＞FA/HL。氫氧化鈣添加適量的BFS(≦25-28wt%)或BOF(≦28-44wt%)製備的吸收劑反應性高於氫氧化鈣本身。

關鍵字

氫氧化鈣 ； 高爐爐石 ； 轉爐爐石 ； 二氧化硫 ； 空氣污染防制

並列摘要

A differential fixed-bed reactor was employed to measure the reactivities of iron blast furnace slag(BFS)/Ca(OH)2 (HL) and basic oxygen furnace slag(BOF)/Ca(OH)2(HL) sorbents towards SO2 at high temperatures(750oC -950oC) and medium SO2 concentration(3000ppm) of flue gas. The one hour utilization of Ca and SO2 capture of sorbent increased with increasing reaction temperature, whether the sorbent had been slurried or not. Slurried BFS/HL sorbents were more reactive than unslurried ones, mainly due to the formation of calcium silicate hydrates in the slurried sorbents. The sorbent reactivity reached the highest at a BFS/HL ratio of 10/90 and decreased with increasing BFS/HL ratio thereafter. While the BFS particles enhanced the dispersion of HL particles and thus raised the sorbent reactivity at low BFS/HL ratios, they were low in reactivity and caused the coherence of sorbent particles at temperatures>750oC and thus reduced the sorbent reactivity at high BFS/HL ratios. Slurried BOF/HL sorbents had higher reactivities than unslurried ones because the sorbent particles were smaller and better mixed. The sorbent reactivity reached the highest at a BOF/HL ratio of 10/90 and decreased with increasing BOF/HL ratio slightly thereafter. BOF/HL sorbents were more reactive than BFS/HL sorbents, because BOF particles didn’t sinter and had a high content of ferric oxide, which can catalyze the reaction with SO2 at high temperatures. For BFS/HL sorbents with a BFS/HL ratio<30/70, the high temperature reactivity was much higher than the low temperature reactivity, measured at 60oC, 70%RH, and 1000ppm SO2 in a previous study. For BOF/HL sorbents, the high temperature reactivity was significantly higher than the low temperature reactivity at each BOF/HL ratio. Comparing the high temperature reactivities of sorbents prepared from BFS/HL, BOF/HL, and fly ash(FA)/HL indicated that the SO2 capture of sorbent varied in the following order: BOF/HL > BFS/HL > FA/HL. Sorbents with reactivities higher than HL alone can be prepared by adding a suitable amount of BFS(less than 25-28wt%) or BOF(less than 28-44wt%) to HL.

並列關鍵字

hydrated lime ； Iron Blast Furnace Slag ； Basic Oxygen Furnace Slag ； SO2 ； air pollution control

參考文獻

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