CS214405B1 - Process of producing olefins by pyrolysis of hydrocarbons - Google Patents

Abstract

The invention relates to a method for producing olefins by pyrolysis of hydrocarbons from petroleum fractions. The problem of upgrading hydrocarbon raw materials to olefins to a greater extent is solved. Hydrocarbons from a petroleum fraction with an average boiling point of about 200 °C, which contains 12 to 20 wt. % of aromatics with a low degree of substitution of longer and branched alkyl chains, are subjected to pyrolysis at a temperature of 600 to 900 °C at a partial pressure of less than 100 kPa and a residence time of less than 3 seconds.

Description

214 405 1

The present invention relates to a process for the production of olefin pyrolysis hydrocarbons from petroleum fractions.

So far, the production of olefins has been the mid-temperature pyrolysis of hydrocarbons and has included the basic processes of petroleum processing into petrocheraicals. In addition to the desired olefins, ethylene, propylene, butadiene, cyclopentadiene, and isoprene also provide aromatics, particularly benzene, toluene, xylenes, and styrene, from liquid pyrolysis products. Most preferred are the hydrocarbon gases containing ethane, propane, and n-butane for the pyrolysis. Due to the lack of gaseous feeds and gasoline, medium-middle distillates are also used, and in particular gas oils are used. The use of medium petroleum fractions as a raw material for pyrolysis has several drawbacks compared to the spraying feeds. The major inadequate is the relatively smaller ethylene yield, which is about 22 wt%. In an attempt to increase ethylene production by the present pyrolysis regime, i.e. by increasing the temperature and shortening the reaction times, fewer C-j and heavier products, but more methane, the heaviest condensation products and coke are produced. Coke formation is a major limiting factor in many ways, since it is closely related to the length of the working period. In addition to the working conditions, the composition of the feedstock is also influenced by the composition of the feedstock. The intensity of coking increases as we move from pulls to heavier petroleum fractions, and there is a change in the deposition of carbon deposits. While in the pyrolysis of the primary gasoline, it is more strongly deposited in the tubes of the furnace radiation section in the decomposition of the gasoline, in the pyrolysis of the gas oil, more in the waste heat boiler (TLE). The aforementioned drawbacks are eliminated by the process for the production of olefins by pyrolysis of carbon monoxide, which involves subjecting the petroleum fraction hydrocarbons having a mean boiling point of about 200 ° C to a boiling point of from 170 to 240 ° C which contains 12 to 20 wt. low-substitution aromatics of longer and branched alkyl chains at 600 to 900 ° C preferably 700 to 850 ° C at hydrocarbon partial pressure of less than 100 kPa and less than 3 seconds, preferably less than 300 ms.

In the present invention, progress has been made in recovering the hydrocarbon feedstock to olefins to a greater extent. In the pyrolysis of hydrocarbons from the 180 to 240 ° C fraction, 22 to 34% ethylene yields are obtained, which are at the level of pyrolysis of the primary gasoline. . Increased V v in ethylene extracts can be obtained without the need to increase the reactor outlet temperatures. During pyrolysis, the coke is more evenly deposited in both sensitive locations / furnace tube, TLE / pyrolysis plant, thereby extending the working time.

The subject matter of the invention is apparent from the exemplary embodiment without being limited to the examples. Example 1.

Pyrolysis was carried out at a flow rate of stainless steel peace reactors at a temperature range of 600 to 900 ° C. The pressure ranged from 0.05 to 0.5 MPa and the rest of the trap was less than 1 second. Work was carried out in the presence of an inert diluent. An aqueous vapor of 20 to 150% by weight and a hydrocarbon spray was used as inert diluent. Petroleum fractions with a boiling point of 100 to 400 ° C were pyrolyzed. In the example of the transfer, the fraction of the following properties was pyrolyzed: start of distillation: 180 ° C distillation horse: 240 ° C density at 20 ° C: 792.5 kg / m 3 average molecular weight: 170 aromatic content: 20% vol / PIA method n-alkanes content: 28% wt. Structural analysis by NMR /% w / w carbon in an aromatic ring without tertiary carbon: 11.5 carbon in -poly aromatic book: 3.7 carbon in aliphatic CH- and CHg-groups: 54.1 carbon in aliphatic CH 2 -groups: 28.7 aromatic content: 16.0 aromatic ring substitution: 31.9 In comparison with kerosene and atmospheric gas oil, the pyrolyzed fraction, including in the dastillation range of 180 - 240 ®C, is practically free of condensed aromatics. which is also characterized by a relatively small aroma content and a smaller number of substituents on the a-romate ring. The yields of profiling pyrolysis products and reaction conditions are shown in Table 1.

Quivering 1. Extracts of gaseous products from pyrolysis of fraction 180 to 240 ®C, kerosene and gas oil Starting material 1 1 1 2 3 Temperature, ° C 800 820 830 800 800 Water vapor ratio 0.75 0.75 0.75 0 , 75 0.75 Delay time, s 0.132 0.186 0.156 0.130 0.153 Pyropolymer yield,% wt. 55.1 62.4 71.5 54.13 52.84 Methane 13.28 18.38 16.32 12.16 12.92 Tent 3.86 4.03 3.59 3.18 5.20 Ethylene 22, 02 26,27 34,55 19,52 18,63 Propylene 7,41 6,54 6,80 9,20 7,29 1,3-Butadiene 2,91 2,39 4,19 3,01 2,93 Rest cj in pyroply 5.62 4.79 6.05 7.05 6.07

a / 1 - fraction with a boiling point of 180 to 240 ° C

2 - kerosene with a boiling point of 132 ds 236 ° C

3 - Gas oil boiling point © d 245 to 360 ° C

Claims (1)

EXAMPLE 2 The pyrolysis of the 180-240 ° C fraction was carried out without the presence of water vapor in order to obtain coking data. Pyrolysis was carried out at a temperature of · 820 ° C. The results are shown in Table 2. Table 2 also shows coke extracts for gas oil and kerosene pyrolysis for comparison of coking. Table 2. Coke formation / in grams / in steam-free pyrolysis of medium oil fractions, at 0 residence time 5 e. Raw feed: 26 g / hr. Experiment, min 5 15 25 30 45 Fraction, 180 - 240 ®C - 0.15 - 0.25 0.25 Kerosene / PL-6/135 - 235 ® - 0.20 a / Gas Oil 0.2 and / a / totally coking reactor at the highest temperature site The formation of coke during the pyrolysis of the individual oil fractions was observed without the presence of water vapor from the bottom to achieve the conditions of hard pyrolysis, 8o allowed to shorten the experiment period. SUMMARY OF THE INVENTION The process for the production of olefins by pyrolysis of hydrocarbons in the presence of water vapor at a temperature range of 600 to 900 ° C, preferably 750 to 850 ° C, characterized in that hydrocarbons from a petroleum fraction having a mean boiling point of about 200 ° C are used. boiling range from 170 to 240 ° C, which contains 12 to 20% by weight of aromatics and a low substitution degree of alkyl chains at a pressure of 0.05 to 0.5 MPa and a residence time of less than 3 seconds, preferably less than 300 ras. Price: 2,40 Kčs Printed by Moravské tiskařské závody, operation 12, Leninova 21, Olomouc