Kinetic Analysis of Iron Blast Furnace Slag/Hydrated Lime Sorbents with SO2 at Low Temperatures

爐石／氫氧化鈣吸收劑與二氧化硫低溫下之反應動力學分析

劉瓊芳(Chiung-Fang Liu) ； 施信民(Shin-Min Shih)

《Journal of the Chinese Institute of Chemical Engineers》 37卷2期 (2006/03) Pp. 139-147

https://doi.org/10.6967/JCICE.200603.0139

摘要

本研究以微分固定床反應器，在模擬噴霧乾燥除硫系統中的袋式過濾器的條件下，探討爐石/氫氧化鈣吸收劑與二氧化硫於低溫下之反應動力學模式。爐石/氫氧化鈣吸收劑重量配比為30/70，於65℃漿化16小時後乾燥後研磨製備而成。該吸收劑對二氧化硫之反應性比氫氧化鈣佳。吸收劑之起始反應速率與鈣最終利用率明顯隨氣相中相對溼度的增加而增加。溫度與二氧化硫濃度對起始速率有些微影響，對鈣最終利用率之影響則可忽略。吸收劑與二氧化硫的反應可用表面覆蓋模式很好地描述；該模式假設吸收劑晶粒表面之化學反應為速率控制步驟，並且考量被產物覆蓋的表面積。本研究的結果有助於使用爐石/氫氧化鈣作為吸收劑的乾式與半乾式除硫系統之設計與操作。

並列摘要

A differential fixed-bed reactor was employed to study the reaction between iron blast furnace slag (BFS)/hydrated lime (HL) sorbent and SO2 under conditions similar to those in the bag filters of a spray-drying flue gas desulfurization system. The BFS/HL sorbent was prepared at a weight ratio of 30/70 with a slurrying time of 16h and a slurrying temperature of 65℃. The sorbent was highly reactive towards SO2 as compared with hydrated lime alone. Increasing the relative humidity of the gas significantly increased the initial reaction rate and the ultimate Ca utilization of the sorbent. The temperature and SO2 concentration had slight effects on the initial reaction rate and negligible effects on the ultimate Ca utilization. The reaction kinetics of the sorbent with SO2 was well described by the surface coverage model, which assumes that the sulfation rate is controlled by the chemical reaction on the sorbent grain surface and takes into account the surface covered by the product. The results of this study are useful for the design and operation of dry or semidry processes that use BFS/HL sorbents to remove SO2 from flue gas.

並列關鍵字

Flue gas desulfurization ； Ca(OH)2 ； Iron blast furnace slag ； Kinetics ； Mathematical modeling ； Multiphase reaction ； Pollution