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Study of SiO2 coat preparation and its anti-coking behaviour

Abstract A SiO2 coat was prepared on an HP40 steel surface via atmospheric-pressure chemical vapour deposition (APCVD). The composition and surface appearance of the coat were then investigated with the aid of energy dispersive spectrometry and scanning electron microscopy, and its anti-coking ability was analysed by virtue of anti-coking mechanism and an anti-coking test. A 5 μm-thick SiO2 coat was prepared through APCVD at 800°C, with tetraethyl orthosilicate as the source material and air as the carrier and diluent gas. The prepared SiO2 coat can effectively prevent catalyst coking (with an anti-coking rate above 70%) under pyrolysis conditions and can improve the anti-coking ability of HP40 steel.