包覆層下管線腐蝕檢知技術開發與研究-以某石化廠為例

隨著石化廠的管路使用年限越久，因為腐蝕而引起管線穿孔、斷裂等事故的隱憂也越大，起因於製程管線外部腐蝕而造成內容物洩漏，英國SHELL公司發表資料顯示35％腐蝕意外事件來自於包覆層下腐蝕(Corrosion Under Insulation,CUI)，ExxonMobil公司也指出因為CUI發生管線洩漏佔80％，管線維護費用有60~80％來自於CUI洩漏問題，因此對於腐蝕管線進行可靠性的評估、預知保養等也就更顯重要，目前常用的CUI檢測方法各有優缺點，其中紅外線熱顯像有著輕便容易攜帶、不用接觸、簡單判讀等特點，相當適合CUI檢測，本研究為開發紅外線熱顯像對於石化廠的現場管線CUI的檢測技術，將於石化廠現場進行熱影像檢測，針對容易產生腐蝕的關鍵點進行重點檢視，實驗中將探討現場管線材質、管徑大小、管件型式、包覆層材質、及流體溫度對於紅外線熱影像檢知之影響，並將結果加以整理，期望能發展出一套適合石化廠管線的腐蝕檢測技術，節省維修成本及提昇安全管理，提供各界參考。紅外線熱顯像對於CUI的檢測中顯示：熱輻射越大，則熱顯像的效果越明顯，定期以紅外線熱顯像方式進行管路檢測可檢視溫度的變化以及早發現管路腐蝕的發生。

關鍵字

包覆層下腐蝕； CUI ；紅外線熱影像；石化廠

並列摘要

CUI refers to the external corrosion of piping which may cause failures, pitting or cracking under insulation due to contents leakage and is a real threat to chemical processing industries, petrochemical plants and related industries. According to the data of Shell (UK), 35% of the corrosion incidents were due to CUI. 80 percent of the leaks and also 60-80 percent of the maintenance expenditures result Therefore, effective corrosion evaluation, preventing external corrosion or cracking under insulation and predictive maintenance are particularly important. There are a number of methods used today to inspect for CUI. Each has both advantage and disadvantage. One of the method now available is Infared Thermal Imager. Infared Thermal Imager is a non-contact, light-weight, easy to carry, safe and effective device of inspecting CUI in plant operations. The research is to develop inspecting techniques with infrared thermal imaging for corrosion under insulation problems of piping in petrochemical plants where the most common locations to find CUI would be detected on the site. In the research, piping materials, size, form of pipe fitting, insulation materials and fluid temperature would be tested to study if the infrared thermal imaging is affected by them and the results of the studies will be analysed thoroughly. Looking forward to developing a proper way to inspect for CUI of petrochemical plants to reduce the maintenance expenditures and enhance worker safety , for all walks of life reference. According to the inspection of Infrared thermal imaging for CUI, the stronger the heat radiation is, the more clear the development of a thermal imager is. To discover earlier the happening of CUI, the pipeline temperature variations should be deteceted periodically by a thermal imager.