- 期刊
鐵礦燒結製程線上脫硫、脫硝技術開發
In-Plant De-SO_x, De-NO_x in Iron Ore Sintering Process
摘要
在一貫作業煉鋼廠中，燒結礦為高爐最主要的含鐵原料。由於燒結製程的特性，相當量的硫氧化物（SOx）及氮氧化物（NOx）被排放至大氣中。以中鋼公司年產800萬噸粗鋼之現況分析，由燒結場所排放之SOx，約佔鋼鐵廠排放總量的51%，NOx則約佔48%。本研究的重點在於燒結原料中添加適量的尿素，抑制SOx及NOx的形成，取代傳統的廢氣處理法。實驗室研究結果顯示，SO_2與尿素在120℃左右反應形成硫酸銨（（NH_4）_2SO_4）。現場試驗結果顯示，原料中添加0.025wt%之尿素可使SOx排放量降低32%，NOx降低15%。對燒結生產及品質無任何負面影響，管路殘氨量亦無增加，廠房周邊亦無氨氣出現。燒結原料中添加尿素對改善NOx、SOx排放之效益包括SOx降低所節省之污染稅，與SCR液氨減少之使用量。將來如能應用到現場，以中國鋼鐵公司四座燒結場估算，每年約可節省新台幣約二千五百萬元。另添加尿素以達到改善NOx、SOx排放的方法，無需增加新的設備或修改既有的流程，更無投資或工程上的困擾，是一實用性及可行性相當高的線上脫硫、脫硝技術。
並列摘要
Iron ore sintering is an agglomeration process to convert iron ore fines into lumpy agglomerates, As the coke breeze is combusted in the sintering process, a significant amount of waste gas including sulfur oxides (SOx) and nitrogen oxides (NOx) is released to the air. An internal survey from China Steel Corporation showed that nearly 51% of the SOx and 48% of the NOx were generated from the sinter plants which represented the main pollutant source in an integrated steelworks. This study takes a different approach, aiming at reducing the formation of NOx and SOx during sintering rather than treating the waste gas. A bench scale study had clarified that the SO_2, reacted with urea at 120℃ and formed ammonium sulfate ((NH_4)_2SO_4). Plant trial also showed that an admixing of 0.025 wt% urea into sinter raw mix led to a decrease of 32% SOx and 15% NOx emissions. There are not any negative effects on the plant production or sinter qualities, and no NH3 was found around the sinter plant. An estimated benefit of using urea in sintering process showed that a saving of 25 million NT dollars per year can be reached, including the reduced payment in SOx pollution tax and the reduced usage of SCR ammonia solution. This approaching method requires no additional facilities or modification of existing equipment. It is a highly feasible and practical countermeasure for in-plant de-NOx and de-SOx.
延伸閱讀
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