ABSTRACT
The presence of impurities in the crude oil especially trace metals and chlorides are the primary responsible for the deterioration of the coiled-pipes of the tubular furnaces, and therefore for their premature failure. Mainly as a result of the acceleration of different types of corrosion processes in addition to the catalyst poisoning reaction. The small quantities of such these impurities which are existed in the heavy crude oils are large enough to cause significant industrial problems annually, environmental hazards and economic losses. Coiled-pipes of tubular furnaces are subject to extreme operating conditions from the prolonged exposure to the high temperatures and the aggressive environments on their alloys, because of these types of furnaces are constantly working (24 hours a day — 7 days a week). The inevitable consequences for the coiled-pipes utilization (or other elements) of the tubular furnaces can be summarized as; the reducing of the corrosion resistance of the coiled-pipes alloys, the increasing of the tendency to unexpected coiled-pipes ruptures, releasing flammable materials, fires, explosions, injuries and unfortunately deaths. As long as corrosion is the most dangerous process, which can negatively affect the elements of the tubular furnaces and especially on the coiled-pipes, this research is devoted to find a solution for very important industrial problem of the premature failure of the coiled-pipes of the tubular furnaces of the dewatering and desalting installation at oil refinery «ELOY» which is located in Syria by using two furnaces to make a closed small-scale heating cycle with temperature range 400 - 700°C. Role of different kinds of chlorides which are existed in the Syrian heavy crude oil is carefully studied due to their high concentrations; accordingly, a whole mechanism for chloride corrosion cycle inside the coiled-pipes of tubular furnaces is suggested. Roles of trace metals which are existed in the Syrian heavy crude oil are also studied in deep in addition to their possible roles in the resulting corrosion types. The responsible mechanisms for each type of corrosion are proposed too.
