Investigating the process of heavy crude oil steam cracking in the presence of dispersed catalysts. II: Investigating the effect of Ni-containing catalyst concentration on the yield and properties of products

The process of heavy crude oil (HCO) steam cracking under a batch regime at 425°C in the presence of Ni-containing nanodispersed catalyst (0.3–2.0 wt % with respect to Ni) is investigated. It is established that using this catalyst facilitates the upgrading of semi-synthetic oil produced from HCO: the Н: С ratio rises (in comparison to steam cracking with no catalyst), and the sulfur content and viscosity are reduced. The Н: С ratio in the liquid products grows slightly along with the catalyst content, but the yield of liquid products falls from 81 to 76% during the process with a simultaneous increase in the yield of coke and gaseous products (from 8 to 13 and from 2 to 4 wt %, respectively). Catalyst with coke residue is investigated by means of XRD and TEM. It is shown that nanosized particles of the Ni9S8 phase with sizes of 15–40 nm form from the catalyst precursor (Ni(NO₃)₂ · 6H₂O) under the process conditions. The selection and investigation of catalytic systems for heavy crude oil cracking in the presence of superheated steam, along with optimization of the process conditions, are required to further enhance the efficiency of the upgrading process.