Abstract
This study presents a comprehensive analysis of the industrial processing technology for high-sulfur crude oil from the Karazhanbas field at the integrated ELOU-AVT and BO unit of CASPI BITUM LLP. To enhance the physicochemical properties of bituminous binders, technological parameters for the production of modified road bitumens were developed and optimized by incorporating a secondary raw material – the darkened vacuum fraction (DVF). The compounding scheme involving vacuum residue blended with by-products of vacuum distillation (heavy vacuum gas oil and the darkened vacuum fraction) prior to the oxidation stage was systematically investigated. It was established that introducing 5-15 wt.% of DVF into the vacuum residue reduces the paraffin content of the feedstock by 15-20% and increases the concentration of aromatic compounds. This compositional modification intensifies the oxidation process and substantially improves the rheological properties of the resulting bitumen. Critical process parameters were identified: the optimal oxidation temperature range of 245-255°C and a maximum allowable residual oxygen concentration in the off-gas of 7 vol.%. Laboratory tests confirmed the consistent production of BND 70/100 and BND 100/130 bitumen grades, which fully comply with the requirements of ST RK 1373-2013. Furthermore, the proposed technology demonstrates a 5-7% reduction in energy consumption and a significant decrease in the volume of non-recyclable industrial waste, contributing to more sustainable production practices.