Abstract: Disclosed is a method for removing sludge in a crude oil storage tank by use of thermal oil discharged from a distillation tower of an oil refinery, such as atmospheric residue, vacuum residue, or vacuum gas oil, and recovering oil having various applications by separating inorganics therefrom. The method is advantageous in terms of minimizing air pollution because of utilizing a closed system, drastically reduced washing time of crude oil storage tank, and continuous removal of the sludge. Additionally, the recovered oil can be provided as fuel oil, marine oil or a feed for secondary treatment processes, such as up-grading processes of heavy oil.

Abstract: Disclosed is a method for removing sludge in a crude oil storage tank by use of thermal oil discharged from a distillation tower of an oil refinery, such as atmospheric residue, vacuum residue, or vacuum gas oil, and recovering oil having various applications by separating inorganics therefrom. The method is advantageous in terms of minimizing air pollution because of utilizing a closed system, drastically reduced washing time of crude oil storage tank, and continuous removal of the sludge. Additionally, the recovered oil can be provided as fuel oil, marine oil or a feed for secondary treatment processes, such as up-grading processes of heavy oil.

Abstract: In the formation of a via contact hole of a semiconductor device, a polymer layer on the sidewall of a photoresist layer and via contact hole is effectively removed and the short of the via contact hole does not occur. For achieving such purpose, a wafer is cleaned in deionized water being added with CO.sub.2 gas during the process used for forming the via contact hole, and a protecting film (Al.sub.2 O.sub.3) is formed on a metal layer. Thereafter, since the polymer layer and a part of the photoresist layer is removed, the metal layer is not eroded and the polymer layer is completely removed.