Protection of Oil Refinery Furnaces Bricks Using Coatings of Nano Zirconia-Glass Composites

Abstract

The process of ceramic or refractory surfaces coating is one of the methods used to protect the ceramic body from chemical effects resulting from operating conditions, especially in the applications that include acid gases emissions such as furnaces of petroleum refining units. A mixture of low-melting glass frit was used, reinforced with nano powders of zirconia and Partial Stabilized Zirconia with yttria (3Y-PSZ) with different additives 5wt% and 10 wt%, as well as the addition of nano-alumina for the same percentage of addition. The medium alumina refractory brick which used in lining petroleum refining units was used as a basis for coating.

The coating process was implemented after mixing and preparation of a homogeneous suspension in the presence of water, then drying and sintering until glazing at a temperature of 850 ^oC. X-ray diffraction technique was used to show the structural characterization of the glazing, which indicated that a glass frit layer was transformed into a mixture of ceramic-glass (crystalline glass), where the crystalline structures of the nano powders were clearly visible. Surface roughness showed low values for frit added with 5wt% of (3Y-PSZ) as well as the frit to which was added 10 %wt of (3Y-PSZ with 5wt% alumina). Moreover, all samples showed clear chemical resistance against acids, including concentrated H₂SO₄. Thermal shock resistance varied for vitrification mixtures, but it was good for vitrified samples, adding 10%wt of (3Y-PSZ) with 5wt% alumina as well as adding silicate to the mixture, and these mixtures are considered to be the best in medium alumina refractory surfaces coating.