OP-II-3

PP-II-26INFLUENCE OF CHEMICAL-ENGINEERING SYSTEM STRUCTUREON EFFICIENCY OF PENTANE-HEXANE FRACTIONISOMERIZATION PROCESSLitvak E., Kravtsov A., Ivanchina E., Chekantsev N.Tomsk Polytechnic University, Tomsk, Russia, e-mail: litvak_egor@mail.ruDecrease of aromatic hydrocarbons content, especially benzene, in automobilefuels with simultaneous maintenance of octane number becomes an urgent problemin connection with the future transition of Russian oil-refining industry to theproduction of motor gasoline satisfying the requirements of «Euro-3» and «Euro-4»standards. It is well known that catalytic reforming, which products are the mainsources of aromatics, remains traditionally the key process of straight-run petrolconversion in Russia. The catalytic isomerization of light alkanes is of the mostinterest in this context, it makes it possible to obtain high-octane component ofautomobile gasoline with minimum benzene hydrocarbons content.Octane number of isomerizate, along with other factors, is determined byselection of process flow scheme. Different schemes of unreacted normal alkanesrecirculation are used for the purpose of conversion level increment.Objective of research is to determine the influence of chemical-engineeringsystem configuration on efficiency of pentane-hexane fraction isomerization process.For this purpose computation of isomerizate composition and its octane number fordifferent schemes was carried out with the support of computer simulation program«Isomer» developed by us. The following process schemes were compared:• One-pass scheme;• Scheme with recirculation of n-hexane and methylpentanes;• Scheme with recirculation of n-pentane, n-hexane and methylpentanes;• Scheme with preliminary disengagement of isopentane from feedstock andrecirculation of n-pentane, n-hexane.The reactor block of installation L-35-11/300 was taken as a basis for thecalculations, catalyst – SI-2. Technological conditions of the process were invariableand were as follows: temperature in the first, second and third reactor – 133 °C,146 °C, 156 °C, respectively; pressure – 2.6 MPa; feedstock flow rate – 90 m 3 /h;hydrogen gas flow rate – 24957 m 3 /h.380