Ti–Mn coating prepared by tungsten inert gas cladding and its inhibiting coking property

Abstract

The Ti–Mn cladding layers with different ratios were prepared on the surface of 310S steel using tungsten inert gas (TIG) technology for inhibiting coking in ethylene cracking, and the cladding specimens were oxidized by muffle furnace for 10 h at 800°C. The coking evaluation tests of the oxidized specimens with different Ti–Mn powder ratios were carried out with light naphtha at 850°C. The results show that when the ratio of Ti to Mn was 3:1, a protective layer of TiO2–TinO2n‐1–Mn5O8 was formed on the surface of specimen, and with the decrease of Ti element content, unstable Fe‐Ti spinel compounds appeared on the surface. When the ratio of Ti to Mn is 1:3, 1:2, and 1:1, the coking inhibition rate was 40%, 46%, and 59%, respectively. Catalytic coke formed on the surface of coating. When the ratio of Ti to Mn was 3:1, the inhibiting coking rate on the surface of the coating reached 80%, and the inhibiting coking performance was optimal, which inhibited the catalytic coking of Fe and Ni metal particles. With the increase of Ti content and the decrease of Mn content, the graphitization degree of coke decreased according to Raman spectrum.