Extending reactor lining service life through thiophene treatment of corroded 304 stainless steel

Background

The lining was a critical component of chemical processing equipment, whose structural stability directly determined production efficiency and product quality. The lining structural damage not only significantly increased the maintenance costs of the equipment but also caused serious influence on the enterprise’s economic benefits. Therefore, research on lining failure mechanisms and protective technology development had the important value of engineering application.

Methods

The lining precursor was prepared using a corundum-aluminum dihydrogen phosphate system, with embedded 304 stainless steel that was calcined to obtain the composite lining. The stainless steel which was extracted from the prepared lining evaluated in a C₃H₆/C₃H₈/H₂ mixed atmosphere. After gas-phase thiophene treatment of the prepared lining, the extracted stainless steel sample was tested under identical conditions for comparison. A systematic analysis on corroded zones of the stainless steel surface was conducted using XRD, SEM, XPS, and electrochemical measurements.

Significant Findings

The passive film of stainless steel was corroded during lining fabrication, leading to Fe₃O₄ formation on the stainless steel surface, which could catalyze hydrocarbon gases converted to filamentous carbon at high temperatures. The introduction of thiophene could poison Fe₃O₄, reduce its catalytic activity, prevent the formation of filamentous carbon, and thereby extend the service life of the lining.