MATHEMATICAL MODELING OF THE GRADUAL DISTILLATION PROCESS USING A SEGMENTAL MODEL AND AUTOMATION OF FRACTIONAL COMPOSITION DETERMINATION BY MICRO-DISTILLATION METHOD

The work describes capabilities of mathematical modeling of gradual distillation for use in scientific research and applied technological problems of determining the fractional composition of a wide class of homogeneous mixtures, including azeotropes. The aim of this work is to develop a segmental mathematical model of gradual distillation of liquid homogeneous mixtures and algorithms for calculating the fractional composition based on this model. The following research methods and tools are used: mathematical modeling, high-precision temperature and flow measurements, the “TEP-PMD” micro-distillation computer complex, the “AD-86” automatic analyzer of the fractional composition of petroleum products, and the Google Colab software development environment. An overview of instruments for analyzing the fractional composition of petroleum products by micro-distillation method is provided. Next, a segmental mathematical model of gradual distillation based on partitioning the fractional composition into transition points is presented. The segmental model is a weighted sum of two or more sigmoids joined at a single transition point T*v. Within the modeling context, the segmental model describes complex S-shaped gradual distillation processes with changes in slope, asymmetry, and abrupt changes in the distillation regime. The work presents algorithms for processing experimental distillation-range data based on the segmental model, and shows that this model adequately describes gradual distillation for a wide class of mixtures; proposes two directions for developing automated fractional composition analysis and computer data processing by micro-distillation method: solving blending problems and calculating the distillation range of crude oil.