Catalytic deparaffinization of middle distillates

Abstract

The middle distillate fractions obtained in primary oil refining plants contain a significant amount of n-paraffins, which have positive pour points, resulting in degradation of the low-temperature characteristics of fuels produced from these fractions. To improve the low-temperature properties of middle distillate frac tions, various depressor additives are used or dewaxing is carried out in various ways. The most efficient dewaxing process is the catalytic one. Classical methods for the secondary processing of hydrocarbon fractions are costly and often uneconomical for small oil refineries. The development of secondary hydrocarbon processing methods applicable at medium and low capacity refineries is an urgent task today. Therefore, our goal was to develop a technology for combined processes of primary distillation of oil coming through the Eastern Siberia – Pacific Ocean oil pipeline system and catalytic dewaxing of the resulting middle distillates. To determine the conditions for carrying out the process of catalytic hydrogen-free dewaxing, an experimental plant of continuous operation was developed with a feed rate of 10 l/h, including a tube furnace, a reactor with a fixed catalyst bed, a heat exchanger, and control and measuring devices. Experiments performed on a pilot plant made it possible to determine the optimal technological parameters for the catalytic dewaxing of middle distillates. It was shown that the catalytic dewaxing of middle distillates under experimentally determined conditions proceeds quite effectively on cracking catalysts SGK-1, SGK-5, KN-30-BIMT, manufactured in Russia. An optimal technological scheme for combining the process of primary oil separation and catalytic dewaxing of middle distillates is proposed. Calculation and optimization of the proposed technological scheme was performed in a computer simulation system ChemCad.