INFLUENCE OF PHENOLIC COMPOUNDS ON THE OPERATIONAL CHARACTERISTICS OF COAL TAR WASH OIL

Abstract

The quality of coal tar wash oil plays a key role in industrial processes for the absorption of benzene hydrocarbons from coke oven gas, and oil stability as well as resistance to polymerisation and corrosive oxidation processes are important aspects for ensuring efficient system operation. To ensure low oil consumption, it is necessary to suppress oxidative degradation processes. In this study, the effects of the phenolics of coal tar and its fractions on the antioxidant properties of the absorption oil were investigated. The results showed that phenols are effective oxidation inhibitors, promoting the formation of a protective film on the metal surface and reducing the corrosion rate of carbon steel from 0.56 to 0.33 mm year -1. A particularly strong protective effect was observed when the anthracene fraction of phenolic compounds was used, which possesses slightly reduced acidity with respect to low-molecular-weight phenols. This result can be explained by the weakening of the strength of the intermolecular interactions between phenolic compounds and pyridine bases. This reduces the negative effect of a decrease in the antioxidant abilities of phenols and increases the antioxidant effect of phenols in the anthracene fraction. The addition of various phenolic derivatives to the working absorbing oil did not have a significant effect on the viscosity or flow characteristics of the oils under study. The introduction of phenolic derivatives into the working oil did not change its coke-forming properties. The introduction of the N,N-dimethylformamide additive into coal tar wash oil did not lead to a decrease in coking properties but slightly decreased the viscosity of the working oil. In general, the obtained results are arguments in favour of the inexpediency of phenol extraction from coal tar wash oil to reduce its consumption due to oxidative processes of thickening.