الفهرس 
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Abstract
As there is a global increasing demand for gasoline and ultra-low sulfur middle distillate, hydrocracking plant became a major part of refinery technology.
Most of the hydrocracking plants experience a corrosion problem; severe local attack of the reactor effluent air cooler (REAC) and associated piping. The situation becomes of great importance in hydrocracker effluent systems where the pipe systems contain the corrosive agents plus flammable hydrogen, naphtha, middle distillate, and high concentrations of toxic hydrogen sulfide at very high pressure (161 atm) so corrosion of reactor effluent air cooler and associated piping has been a serious problem in hydrocracking plants from the day these process was first introduced to the oil industry.
The continuing equipment replacements, unplanned outages, and catastrophic incidents illustrate the current need to better understand the corrosion characteristics and provide guidance on all factors that can affect fouling and corrosion. The ability to predict corrosion attack in these systems is of critical importance because the consequences of failure are significant.
In this thesis, process variables affecting reactor effluent air cooler corrosion are studied to determine route causes for Middle East Oil Refinery (MIDOR) hydrocracker reactor effluent air cooler several corrosion failures ended with tube explosion in the third quarter of 2009 and strategies to promote system reliability. Some of the major causes for several failures were relatively high PH2S for carbon steel, high dissolved oxygen in wash water which proved by analysis of deposit and wash water, and flow regime. Ammonium bisulfide concentration, velocity, hydrogen sulfide partial pressure, temperature, header arrangement, flow regime, wash water quality, wash water quantity, wash water injection point, corrosion inhibitors, inspection methods, material of construction, tube ferrules, fan operation, chloride content, hydrocarbon content, REAC temperature controlling philosophy, and corrosivity factor (Kp) are studied parameters to promote REAC system reliability.