Prediction of catalytic cracking performance during co-processing of vacuum gas oil and low-margin oil refining streams

Abstract

Relevance. Expansion of catalytic cracking feedstock resources both due to the need to intensify the process to increase the yield of target products (high-octane gasoline, light olefins) and to deepen oil refining through the utilization of low-margin streams at refineries. Along with this, there is an urgent need to develop domestic mathematical tools for optimizing the catalytic cracking, predicting the process performance when the modes and feedstock qualities changes, as well as planning of production. This requires in-depth analysis and detailed study of the composition of oil fractions involved in processing and thermodynamics and kinetics of a heterogeneous process. The development and application of a mathematical model of the catalytic cracking, taking into account the composition and properties of the components involved in processing, makes it possible to quantitatively assess the yield and quality of target and by-products depending on the composition, physicochemical properties of the mixed feedstock, and the parameters of the technological regime, with an assessment of the possibility of their processing at an existing industrial facility. Aim. Experimental study of the composition and properties of mixed feedstock of catalytic cracking based on vacuum gas oil containing 5 to 20 wt % of extract of selective cleaning of oils, distillate, residual slack wax, and deasphalted oil, and prediction of the catalytic cracking indicators during their co-processing using a mathematical model. Methods. Liquid chromatography method to study the composition of feedstock materials of the catalytic cracking in combination with a number of standard methods for determining physico-chemical properties. Results. Using a set of experimental studies, the authors have established the patterns of changes in the composition and physico-chemical properties of the components and mixed feedstock of catalytic cracking containing 5–20 wt % of distillate and residual slack wax, deasphalted oil, and extract. The results obtained were used in development of a mathematical model of the heterogeneous catalytic cracking of feedstock, which takes into account the composition of oil fractions involved in processing and the patterns of catalyst deactivation by coke. Using a mathematical model, the authors established the patterns of changes in the composition and yield of process products when 5–20 wt % were involved in processing distillate slack wax and extracts of selective cleaning of oils mixed with vacuum distillate. Practical recommendations were developed on the possibility of expanding the hydrocarbon feedstock of the catalytic cracking, taking into account the fuel or petrochemical regime.