石油焦品質劣化對煉鋁的衝擊及因應

2019年全球原鋁產量約6,300萬噸，需使用2,500萬噸陽極焦製作預焙陽極及20萬噸優質焦製作石墨化陰極碳塊，陽極焦及優質焦皆來自重質油原料經延遲結焦製程得到生焦再經煅燒成熟焦。隨著原油重質化、煉油業要求提升輕質油收率及2020年國際海運要求使用硫份0.5％燃油的影響，使得延遲結焦的進料呈現劣質化，導致石油焦品質劣化的趨勢將會更明顯。石油焦品質劣化指標包括硫含量增加及金屬含量增加，前者造成增加二氧化硫排放、電極表面缺陷及電解性能下降，後者降低電解電流效率及增加陽極消耗。本文主要在於說明煉鋁技術簡述、石油焦品質日趨劣化對電解煉鋁的衝擊、煉鋁業的因應方式及煉油業如何利用現有技術提昇石油焦品質以符合煉鋁業未來的需求。

關鍵字

煉鋁；預焙陽極；石墨化陰極碳塊；延遲結焦

並列摘要

The total primary aluminum production reached about 63 MT in 2019, which required 25 MT anode coke and 200 KT premium coke to make prebake anode and graphtized cathode block, respectively. Both cokes were petroleum cokes, produced by delayed coking process and followed by calcination. Due to heavier crude oil、increasing the liquid yield in refinery and fufillment of international marine fuel oil with 0.5 wt% sulfur content in 2020, the feedstocks to delayed coker were expected much heavier gradually . This trend resulted in making petroleum coke quality worse, with high sulfur content and high metal content. The former caused the increase of sulfur dioxide emission , electrode surface defects, and poor electrolysis performance, and the latter led to the decrease of current efficiency and the increase of cathode consumption. This article elucidated the aspects related to aluminum smelting , including technology briefing、impacts from poor quality of petroleum coke、response of smelters and strategy to improve the coke quality in refinery.

並列關鍵字

aluminum smelting ； prebake anode ； graphtized cathode block ； delayed coking

參考文獻

Les, Edwards(2015).Carbon Raw Materials for the Aluminum Industry.Metal Bulletin 30th International Aluminum Industry Conference.(Metal Bulletin 30th International Aluminum Industry Conference).