泡沫系統在油槽火災防護上之設計應用-----以底部注入式改良為例說明

Abstract

油槽火災及爆炸事故，死傷發生率都極高，而破壞力也大，對生產設備及原物料之損失更是難以估計。所以建立油槽火災防護抑制技術，以降低火災爆炸事故之發生頻率與影響程度，對石化產業的永續發展將顯得非常重要。 消防泡沫是一種填充空氣的泡沫水溶液集合體，其密度比易燃性液體低，並可粘著、覆蓋於易燃性與可燃性液體表面而達到隔離空氣、冷卻燃料及防止燃料持續蒸發引燃等功用，所以消防泡沫常使用在易燃性危險液體之預防火災、制壓火勢及防阻延燒上。消防泡沫可使用於固定式或半固定式系統，經由頂部放出口緩慢地排放至燃料表面，也可應用移動式噴嘴或底部注入式系統達到滅火目的。 本論文以儲存易燃性及可燃性液體之常壓儲槽為對象，內容含蓋油槽泡沫系統設計方法，並以工程實例驗證可撓式軟管底部注入法的應用價值。經10年的實地驗證結果，證明可撓式軟管底部注入法不但壽命長且其可用度亦可達0.9814以上，是一個相當穩定良好的系統，在浮頂油槽的火災防護上值得推廣採用。

The fire and explosion accidents for oil tank have very high bloodshed and destructive power. It is hard to estimate what the production equipments and raw materials should be lost in such incident. To establish the fire protection technology of oil tank is very crucial for permanent development of the petrochemistry industry so as to reduce frequency and effect of oil tank fire. Fire-fighting foam is an aggregate of air-filled bubbles formed from aqueous solutions and has a lower density than that of flammable liquids. It is principally used to form a cohesive floating blanket over flammable and combustible liquids and prevents or extinguishes fire by excluding the air and cooling the fuel. It also prevents from reignition by suppressing formation of flammable vapors. Therefore, Fire-fighting foam can be used as a fire prevention, control, or exposure protection for flammable liquid fire hazards. Fire-fighting foam for these hazards can be supplied by fixed or semifixed piped systems. It can be applied through foam discharge outlets, which allow it to fall gently over the surface of burning fuel. And it can also be applied by portable hose streams using foam nozzles or subsurface injection systems. The thesis considers the effective design method for foam system and proves the application value of flexible hose subsurface injection method for a real design case, which is for flammable and combustible liquid hazards and atmospheric storage tanks. In this study, it proves that the flexible hose subsurface injection method not only can be survived longer but also be available to reach above 0.9814 for ten years. Apparently, the system is very good and steady that it is worth promoting and adopting for the fire protection of floating roof tanks.