Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

PP-III-1249775 m 3 /h0,65Initial temperature, °С489481473465Dienes, wt. %0,600,550,500,450,4037,5 m 3 /h45744937,5 m 3 /h25 75 125 175 225 275 325 375 425 475Volume of recycled raw material, thous.m 30,350,3075 m 3 /h25 75 125 175 225 275 325Volume of recycled raw material, thou. m 3Fig. 1. Dependence of temperature of input intodehydrogenation reactor on raw material consumption(prognostic calculation by mathematic model)Fig. 2. Dienes concentration depending onraw material consumption (prognosticcalculation by mathematical model)Therefore for increasing process intensity the initial temperature of input intodehydrogenation reactor should be retained at prior level (as at raw material load 75 m /h pera reactor). Because of contact time increase, and also high temperature of input into reactorthe concentration of by-products (diene hydrocarbons) increases at an average on 15 wt. %and by the end of operation cycle to 50 wt. % (Fig. 2). It results inevitably in formation ofsuch high-molecular compounds as tetralin and indan homologues, polyalkylaromaticcompounds, di-and more phenylalkanets and others (at LAB generation about 200t/day) anddeterioration of a desired product biological decomposability that is inadmissible.The transition to two-reactor scheme provides the decrease of total pressure in the systemdue to reduction of raw material load to one dehydrogenation reactor. It gives the additionalreserve for increasing hydrogen feeding into the system. Therefore it would be reasonable inthis case to increase molar ratio Н 2 /hydrocarbons.Prognostic calculation by the model showed that the average content of desired and byproductcomponents at ratio Н 2 /hydrocarbons, equal 8:1, will be reduced to the level, whenthe set was operating at raw material load 75 m /h per a reactor.Though LAB generation does not exceed the level 180 t/day but the duration of catalystoperation cycle increases in 1,5…1,7 times, that balances the dead time at reactorsoverloading.References1. Kravtsov A.V., Hadartsev A.C., Shatovkin A.A., Milishnikov A.V., Ivashkina E.N., Ivanchina E.D.,Yuriev E.M. Computer modelling of high n-paraffins hydrogenation process on Pt-catalysts // Oil refiningand petrochemistry. Scientific and technical achievements and advanced experience.-2007. - 5. - p. 3533326