Study of the autocatalytic activity of sulphide phases formed on the surface of X18H9T steel in sulphur dioxide reduction
V. SH. ASLANOV1, K. M. SAMEDZADE1, E. B. GAHRAMANOVA2, I. A. TALIBLI1, U. N. SHARIFOVA1
1Institute of Catalysis and Inorganic Chemistry, Ministry of Science and Education, Baku, Azerbaijan
2Azerbaijan Technical University, Baku, Azerbaijan
Keywords: catalyst, sulphur dioxide, hydrogen sulphide, natural gas, granulation sulphides
Abstract
Sulphur dioxide (SO2) is one of the main atmospheric pollutants emitted from sulphide-containing ore processing and fossil fuel combustion. Efficient utilisation of SO2 is a significant task both from the environmental perspective and within the framework of industrial technologies improvement. Investigation of the autocatalytic action of sulphide phases formed on the surface of X18H9T(10T) steel on SO2 reduction using gaseous reducing agents has been carried out. Taking into account literature data, it has been concluded that during the reduction process, mainly iron sulphides (pyrrhotine (Fe1-xS) and pyrite (FeS2)) are formed on the surface of steel, as well as, to a lesser extent, sulphides of nickel (NiS) and chromium (Cr2S3). Sulphide phases formed under the action of reaction medium have been revealed to provide high catalytic activity and synergism in SO2 reduction. In the presence of iron, nickel and chromium, more active reducing agent, hydrogen sulphide (H2S) is formed, which, in turn, amplifies the synergistic effect and intensifies the catalytic process. It has been determined that the addition of Cr and Ni (up to 5 wt% of each element) to iron sulphide phases provides an increase in catalytic activity. These modified sulphides exhibit efficiency not lower than that of the sulphides formed on the surface of X18H9T(10T) steel, despite the higher content of Cr (about 18 wt%) and Ni (about 9 wt%) in the steel itself. A distinguishing feature of the process is in catalyst formation directly during reduction process, which ensures continuous renewal of its activity without the necessity of additional regeneration. The potential for using metal alloys as carriers for self-generated catalysts for sulphur dioxide utilisation is demonstrated.
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