Optimal Design of Heat Exchanger Network in Oil Refineries

Abstract

Today, the main methods of protection against corrosion of contact devices of rectification equipment for oil refining, in particular, stainless steel mesh packing, under conditions of relatively high temperatures (150–250°C) and in the presence of aggressive components in oil feedstock (hydrogen sulfide, sulfides, mercaptans, other sulfur compounds, chloride ions, organochlorine compounds, water) are the use of special alloys as protective coatings, as well as corrosion inhibitors that reduce the corrosive effect of an aggressive environment. At the same time, most of these methods have disadvantages associated with high operating costs, insufficient efficiency, or the ability to protect only from a certain factor, and not from their combination. In this regard, studies of the corrosion resistance of mesh contact devices made of stainless steel grade 12Х18Н10Т, on three types of samples: alloy wire, welded mesh, thin sheet. Titanium nitride (TiN) and metal coatings of nickel (Ni), titanium (Ti) and chromium (Cr) were used as anticorrosive coatings for these samples. These coatings were applied to the samples by two methods: electrolytic method and vacuum ion-plasma spraying. It was found that the optimum thickness of the coating is 10–15 µm, at which the resulting films have sufficient ductility and do not peel off from the surface of the corresponding stainless alloy. The study of corrosion of samples of stainless steel 12Cr18N10T with applied coatings and without coatings was carried out by immersion in compositions containing oil, as well as in simulating aggressive oil-containing media. As a result of the studies, it was found that protective coatings of chromium and titanium nitride, applied by vacuum ion-plasma spraying, are the most effective from the point of view of corrosion protection of stainless steel mesh contact devices used in rectification columns. Keywords: rectification column, mesh contact devices, stainless steel, aggressive media, corrosion inhibitors, anti-corrosion protective coatings.