Failure analysis and quick recovery of a low-temperature distillation station

A coupling model based on hazard and operability analysis (HAZOP) and fault tree analysis is proposed and used to analyze the failure of a low-temperature distillation station (LTDS). It is found that the formation of scale in the deamination tower in the LTDS is the most significant cause for the failure. The scale was mainly composed of SrSO4, CaCO3, CaSO4, and MgCO3, which were determined by various techniques from the gas-field water. Dynamic weight loss experiments were conducted to estimate the corrosion rate of 304 steel with different cleaning solutions. The corrosion behaviors of the metal in the deamination tower were further investigated in three types of cleaning solution via potentiodynamic polarization method. The cleaning solution composed of 6% sulfamic acid, LAN826, JFC, and a defoaming agent could safely and quickly remove the scale covering the LTDS at 50(degrees)C. In addition, the optimal cleaning time was found to be 6 h.