Corrosion inhibition effect of four inhibitors on SA106 Gr.B steel in coal-based syngas produced water

Stripper tower of coal gasification unit easily occurs severe corrosion, which may induce the damage of relative equipment and the leakage of toxic gas. Introducing the organic corrosion inhibitors is an effective and promising way for this system. In this article, the effects of medium concentration on corrosion behavior in coal-based syngas produced water are firstly investigated with X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the protection performance of inhibitors including imidazoline (ID), imidazoline amide (IDA), mannich base quaternary ammonium salt (MBQA), and pyridine (PD) are further explored with electrochemical measurement and the experiment of weight loss. The results indicate that the H2S volume fraction and the volume ratio of C(CO2)/C(H2S) exert significant effects on corrosion behavior. Thus, it is critical to control their concentration within a reasonable range for practical situation. Four inhibitors, especially the MBQA and PD, display prospective inhibition performance under appropriate concentration. Furthermore, compounding inhibitors of MBQA and PD exhibit an optimal inhibition performance with 95.5 % inhibition efficiency. This study provides a new route to protect the stripper tower top of coal gasification unit effectively.