Inhibition of carbon steel corrosion in 0.5 M hydrochloric acid solutions by β-cyclodextrin modified natural chitosan was investigated by weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results indicated that the inhibition efficiency increased with the inhibitor concentration at 298 K. The experimental results revealed that β-CD−chitosan (βcyclodextrin modified chitosan) was a mixed inhibitor with a maximum achievable inhibition efficiency of 96.02%. Adsorption of β-CD−chitosan was found to follow the Langmuir adsorption isotherm which involved both physisorption and chemisorption. The results of SEM and EDS studies further confirmed the inhibition action of polymer.

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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°C. In addition, the optimal cleaning time was found to be 6 h.