Abstract: The present invention relates to a method of preparing water-dispersible poly (urethane-urea) having aliphatic-aromatic isocyanate, more particularly to a method of preparing water-dispersible poly (urethane-urea) having aliphatic-aromatic isocyanate, with improved mechanical/thermal properties, such as heat resistance, chemical resistance and adhesion, good cost competitiveness and environmental friendliness, by reacting polyester polyol, dimethylol propionic acid and an aromatic isocyanate compound to obtain a hydroxyl (OH)-terminated prepolymer, adding an aliphatic isocyanate compound to said OH-terminated prepolymer to obtain an isocyanate (NCO)-terminated prepolymer wherein aromatic-aliphatic isocyanate is hybridized, neutralizing, water-dispersing and chain extending said NCO-terminated prepolymer.

Abstract: Disclosed is a chemical cleaning process for removing fouling from process lines of oil refining or petrochemical plants. The process lines are in an on-line state and a chemical cleaning agent is circulated through the process lines to remove the fouling. It can effectively recover the thermal efficiency in oil refining processes or petrochemical processes within a short period of time, so that significant energy consumption is reduced. Furthermore, the chemical cleaning process requires a shorter cleaning period and therefore allows for a longer operating time. It can also dislodge fouling without opening heat exchangers or other equipment thereby preventing the release of VOCs. As a result, environmental pollution is not generated. The present invention is also ecconomically favorable as it extends the time between periodic maintenance.

Abstract: Disclosed is a cleaning composition useful for dislodging fouling from process lines of oil refining or petrochemical plants and a cleaning method using the composition. The cleaning composition comprises 0.01 to 1 wt % of a C8 aromatic compound, 75 to 85 wt % of a C9 aromatic compound and 14 to 24 wt % of a C10 aromatic compound. When applied to the process lines, the composition is mixed at an amount of 2 to 20 vol % with Light cycle oil or light gas oil. Chemical cleaning with the composition effectively removes the fouling formed within the process lines and heat exchangers of oil refining or petrochemical plants, and recovers the processing capacity of heat exchangers to the start of run level, bringing about a significant economic profit.