高爐爐石/氫氧化鈣與轉爐爐石/氫氧化鈣吸收劑在高溫煙道氣中吸收二氧化硫之研究

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

郭賢章(Shain-Chang Kuo)

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(2009年)

https://doi.org/10.6342/NTU.2009.02227

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(BOFS)/氫氧化鈣(HL)吸收劑在高溫(750℃-950℃)模擬煙道氣含(3000ppm SO2,5% O2,9% H2O,12.5% CO2和N2)中對二氧化的硫反應性。吸收劑漿化過與否，其反應ㄧ小時鈣利用率和SO2 捕捉率均隨著溫度升高而提高。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BOFS/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。BOFS/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。BOFS/HL吸收劑因BOFS 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。因模擬煙道氣含有12.5% CO2，在750oC下，碳酸化反應與硫酸化反應同時產生，硫酸化反應受到輕微抑制。水蒸汽的存在(9%)會顯著抑制硫酸化反應。比較在模擬煙道氣(未含水蒸汽)中與在空氣/二氧化硫混合氣中反應的結果，發現吸收劑的鈣利用率與二氧化硫捕捉率在750oC時前者稍低，其餘溫度下皆差不多。

關鍵字

高爐爐石 ； 轉爐爐石 ； 二氧化硫

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(BOFS)/Ca(OH)2(HL) sorbents towards SO2 at high temperatures(750oC-950oC) in simulated flue gas (3000ppm SO2, 5% O2, 9% H2O, 12.5% CO2, and balance N2) . 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 BOFS/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 BOFS/HL ratio of 10/90 and decreased with increasing BOFS/HL ratio slightly thereafter. BOFS/HL sorbents were more reactive than BFS/HL sorbents, because BOFS particles didn’t sinter and had a high content of ferric oxide, which can catalyze the reaction with SO2 at high temperatures. Because of the presence of 12.5 % CO2 in the simulated flue gas carbonation and sulfation reactions took place simultaneous at 750oC,and the latter reaction was slightly imhibited. The presence of water vapor signficantly reduced the sorbent reactivity. The utilization of Ca and SO2 captures of sorbents reacted in simulated flue gas without H2O were about the same as these in air/SO2 mixture, except the case of 750oCin whuch the results in simulated flue gas wree slightly lower.

並列關鍵字

BFS ； BOFS ； SO2

參考文獻

Shih, S. M.; Hung, J. T.; Wang, T. Y.; Lin, R. B., “Kinetics of the Reaction of Sulfur Dioxide with Calcium Oxide Powder”, J. Chin. Inst. Chem. Eng., 35, 4, 447(2004)

廖坤祥，“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”， 碩士論文，國立台灣大學，台北，台灣(2008)

Agency for Toxic Substance & Disease Registry (ATSDR), U.S., “Sulfur Dioxide”, http://www.atsdr.cds.gov/tfacts116.html(2005)

Al-Shawabkeh, A.; Matsuda, H.; Hasatani, M., “Utilization of Highly Improved Fly Ash for SO2 Capture”, J. Chem. Eng. Jpn, 28, 53(1995)

Badin, E. J.; Frazier, G. C., “Sorbents for Fluidized-Bed Combustion”,