CS252439B1 - The process for the treatment of residual pyrolysis C ^ -racra - Google Patents

Abstract

Method of processing residual pyrolysis Cn-oil remaining after propylene separation from the total C^-fraction separated in the system for separating the purpose pyrolysis products by catalytic hydrogenation together with unsulfurized petroleum fractions with a boiling point between 20 and 540 °C under hydrogen pressure on catalysts containing mixed non-ferrous metal compounds.

Description

The present invention relates to the treatment of residual Cyfraction comprising, in addition to propane and propene, propadiene and methylacetylan produced by the separation of gaseous pyrolysis products, by pressure hydrogenation in an excess of liquid desulphurized petroleum fractions to a propane concentrate devoid of C CH ^ hydrocarbons.

The residual pyrolysis fraction remaining after the distillation separation of propylene from the total hydrocarbon-containing fraction contains predominantly propane and 10 to 40% by weight of hydrocarbons - methylacetylene and propene. The hydrocarbons are very reactive and are the starting components for a number of other syntheses, utilizing primarily the editorial and polymerization reactions which are characteristic of methylacetylene and propadiene. However, this fraction is often used - especially within the ethylene unit - as a fuel gas, since further chemical processing is capital intensive.

Another way of utilizing this fraction is the selective hydrogenation of the ^C 3 ^H 4 hydrocarbons onto propylene, which is then isolated as a valuable component. These processes adversely affect the high reactivity of propadene and methylacetylene as well as the high reaction heat of hydrogenation leading to side and subsequent reactions. In this way, polymeric substances are formed which, during heterogeneously catalyzed gas phase hydrogenation, adsorb on the catalyst surface to form deposits, which is associated with a rapid loss of activity.

For this reason, the hydrogenation of both the ethylene and allene hydrocarbons is carried out in the liquid phase on catalysts allowing these hydrogenations to be carried out at low subcritical temperatures. The active ingredients of these catalysts are mainly platinum koys 252439 deposited on the active support and the liquid phase is a hydrogenated fraction which elutes the high-boiling polymers from the catalyst pores. For homogeneous catalysis (e.g., the Vapidrol process), one uses homogeneous catalysis processes to hydrate the saturation of the multiple vax. Hydrocarbonation processes for highly unsaturated fractions always require special equipment to solve the reaction heat removal in a system where the presence of a liquid phase of otherwise gaseous hydrocarbons is required.

In order to overcome these disadvantages, according to the invention, the treatment of the residual C ₃ fraction from the pyrolysis comprises, in addition to propane, the C ₃ H ₄ hydrocarbons, by combining this fraction and liquid petroleum fractions boiling in the range of 1: 1. 20 to 190 ° C and / or 150, to 250 ° C and / or 150 to 360 ° C and / or 290 to 540 ° C in a weight ratio of 1 to 20 to 1: 200 and with a hydrogen-containing gas in addition to saturated hydrocarbons. to HgS, wherein the mixture is heated to a temperature of 250 to 450 ° C under a pressure of 20 to 20 bar in the presence of a catalyst. containing Ni and / or Co and Mo and / or W in the form of sulphides on the active alumina, optionally activated silica, phosphorus or fluorine, and from the reaction product, propane-rich and unsaturated gaseous hydrocarbons are separated. And at the same time a liquid desulfurized hydrocarbon fraction is obtained. '''·

The advantages of the novel process utilized in the refining and petrochemical practice resides in the fact that so-called. Residual C ₃ -fractions containing significant amounts of propadiene, and methylacetylene is simply introduced into any of the usual oil distillation products such as gasoline, kerosene, diesel oil or a vacuum distillate and together and it is passed to a hydrotreating step in which the under-mentioned conditions achieves desulfurization of petroleum products, and saturated C ₃ -uhlovodÍ.ků. Exothermicity of the reaction allows to reduce, depending on the concentration of unsaturated C ₃ -uhlovodiků a mixed fraction, the inlet temperatures for the desulfurization and to utilize the resulting heat to improve hydrogenačnlho hydrotreating process. 2 unsaturated C ₃ -uhlovodiků propane formed is collected together with other C ₂ to C ^ -uhlovodiky and additional insulation can be obtained by pyrolysis propane concentrate or as kompo252439 nents for propane - butane.

Example δ. and

The residual C 1 fraction separated in the pyrolysis gas separation system has the following composition (% by weight):

propane 69.0 propene 1.1 butanes 0.9 propadiene 15.2 methylacetylon 13.8 and is combusted within the olefin unit as fuel gas. Podlo. according to the invention, this fraction is introduced into a straight-run naphtha obtained by distillation of oil and boiling in the range of 20 to 190 ° C and having a sulfur content of about 300 ppm by mass. The weight ratio of the two components is 1: 50J. .):,

13.0. · '3.5 ·

0.1 on active alumina.

The hydrotreating conditions are as follows:

temperature (° C) 30Θ pressure (MPa) * 3,5 load LHSV (h ^{1 1} )! ^ ratio K ₂ (gas) / hydrocarbons (cap.) (v / v): 500: 1 from reaction The product is distilled off by gaseous hydrocarbons, the proportion of hydrocarbons having three carbon atoms in this gaseous product is as follows: (% by weight) Propane ¢ 98.0 Propene 1.1 Propadiene 0.1 Methylacetylene traces

The sulfur content of the obtained hydrotreated gasoline is below 1 ppm.

MoO, Fr.

CoO

Na ₂ ^ů

The same C ^-fraction as in Example 1 is mixed with the petroleum fraction obtained by distillation of oil and boiling in the range of 190 to 240 C with a sulfur content of about 2045 ppm hmaZ. The weight ratio of the two hydrocarbon fractions is about 1:40 (C-fraction: kerosene).

Example 2

The mixed raw material thus obtained is subjected to catalytic hydrogenation on a catalyst as in Example 1.

The hydroprafination conditions are as follows:

. temperature (° C) 290 pressure (MPa) 3.0 load LHSV (h ^-1 ) 1.5 pomof Hof / gas (cap.) (v / v) i 500: 1 from reaction product distil gaseous hydrocarbons representation hydrocarbons with three carbon atoms in the product gas is as follows: (w _e propane 99.2 ♦

The sulfur content of the hydrotreated kerosene obtained after removal of hydrogen sulfide is below 10 ppm by weight.

Example 3

The same C ^-fraction as in Example 1 is mixed with a primary gas oil obtained by distillation of oil and boiling in the range of 150-300 ° C with a sulfur content of 1.08% tactile. The weight ratio of the two hydrocarbon fractions is 1: 45.

The mixed feedstock so obtained is subjected to catalytic hydrotreatment on the catalyst described in Example 1. The hydrotreatment conditions are as follows: temperature (° C) 320 pressure (MPa) 8.3 LHOV load (h ~ ^L ) 1.5 ratio H. _? (gas) / hydrocarbons (k'ap,) · (v / v): 500: 1 distillates from the reaction product gaseous hydrocarbons, representing hydrocarbons having three or more carbon atoms in these gaseous products, as follows; : (% by weight) Propane 99.2 Propene 0.0 prophylactic traces of triethylacetyl traces

The sulfur content after removal of hydrogen sulfide in the liquid product is 0.26% by weight.

Example 4

The same C fraction as in Example 1 was mixed with the primary vacuum obtained by distillation of crude oil and boiling between 290 and 540 C with a sulfur content of 2.1% by weight. The weight ratio of the two components is 1:40.

The mixed feed thus obtained is subjected to catalytic hydrogenation.

The catalyst has the following composition: (wt.%)

W / 0 ₃ '24.5

NiO · 8.3

Pe., 0 ... 0.04

O. .

on gamma alumina. /.

The hydrogenation conditions are as follows:

temperature (° C) 430 '• pressure (MPa) 20 load LI-ISV (h “ ¹ ) 1,0 ratio H _o (gas) / hydrocarbons (cap.) / (v / v): 1000:

From the reaction product, gaseous hydrocarbons, representing three hydrocarbon hydrocarbons, are distilled off in these gaseous products, as follows. :

propane 99,9 'propene traces propadion traces methylacetylene traces

Claims (1)

A process for the treatment of residual Crak-fraction from the pyrolysis of hydrocarbons falling off in a system for the separation of special-purpose products and containing propane and methylene ethylene in addition to propane and propylene, characterized in that this fraction combines i: 20 to 1: 200 by weight with liquid boiling oil fractions. between 20 and 190 ° C and / or 150 to 250 ° C and / or 150 to 360 ° C and / or 290 to 540 ° C and with a hydrogen-containing gas in addition to saturated hydrocarbons up to C ₄ and hydrogen sulfide, the mixture being heated to a temperature 250 to 450 ° C under a pressure of 2.0 to 20.0 MPa in the presence of a catalyst containing Ni and / or Co and Mo and / or W in the form of sulfides on active alumina, optionally activated silica, phosphorus or fluorine and it rectally separates propane-rich gaseous hydrocarbons, depleted of C ₃ H ₄ , alongside the liquid desulfurized hydrocarbon fraction.