CS254941B1 - A method for producing 1-alkenes of C 5 to C 18 - Google Patents

Abstract

The production of 1-alkenes Cs to Cis is carried out by thermal cracking at a temperature of 500 to 700 °C mainly of saturated hydrocarbons in the range of Cs to Cso, obtained by hydrocracking petroleum fractions, especially vacuum distillates. Paratinic. crude oils, as well as products of their physical processing, e.g. gáčov. The production method is suitable for expanding the raw material] toase of higher alkenes, especially 1-alkenes in the chemical industry.

Description

The present invention relates to a process for producing mainly 1-alkenes C6 to Cm by thermal cracking of non-traditional hydrocarbon feedstocks.

Higher n-aikenes with a double bond at the end of the chain (1-alkenes) are produced by catalytic oligomerization of ethylene, followed by dehydrogenation of n-alkanes followed by metathesis or ethenolysis or chlorination of n-alkanes followed by dehydrochlorination and ethenolysis as internal n-alkenes. thermal cracking of solid paraffins, including chees (Weissermel, K., Arpe, HJ, Industrial Organic Chemistry, SNTL Prague [1984]; Macho, V., Chemical Industry 33, 666 [1985]; Freund, H. et al.: Paraffin Products, Properties, Technologies, Applications Akadémiai Kiadó, Budapest [1982]] Parallel chain alkenes with an internal double bond position are industrially produced from n-alkanes, either by chlorination followed by dehydrochlorination or catalytic dehydrogenation.

However, despite the evidently preferred processes mentioned above, in the case of the production of higher 1-alkenes by the oligomerization of ethylene (the so-called Alfen process), the disadvantage is the energy consumption of ethylene as a feedstock and the catalytic oligomerization system. Often, not enough solid paraffins are limiting for thermal cracking. By n-alkane clilorization procedures followed by dehydrochlorination or dehydrogenation of n-alkanes, n-alkenes are obtained with virtually only internal double bonds, the content of 1-alkenes being below 4%. Tek, 1-alkenes can only be prepared by subsequent metathesis (Masters K .: Comogennyy kataliz perechoduymi metallami. "Mir" Moscow [1983]), or by ethenolysis, whereby alkenes produce 1 alkenes with a much lower molecular chain length. in the case of metathesis or ethenolysis under catalytic action, especially the compounds Re, Mo, W react the alkenes by their double bonds while cleaving the molecules at the double bond sites).

On an industrial scale, predominantly 1-alkenes have been produced by cracking solid paraffins and slacks, with enough attention being paid to the study of process process parameters (Japanese Patent 7300750 [1973]; C.A. 79,115,100 f; 72,21083 [1972]; C.A. 79, 78061 and 731882 [1973]; C.A. 79, 81363 b; 7307601 [1973]; C.A. 79, 4975a; Kirichenko S. P. and others: Tr. Inst. Cim. Nauk Akad. Nauk Kaz. SSR, 32; 87-108; C.A. 79, 92610I; Hrušovský M .: Oil and Coal 15, 59 [1973]; Giraud J. et al.: Inform. Chim. no. 184, Dec. [1978]) as well as] the cracking reaction mechanism (Vinnitsky et al., Neftechimija 13, 422 [1973]; Kalinenko RA et al.: Neftechimija 12, 698 [1972], Thermal cracking of petroleum fractions, but mainly of paraffins, slacks and slack. in particular through the urea intermediate adducts obtained from petroleum fractions of n-alkanes boiling in the range of 280 to 450 ° C and up to 500 ° C, it is most often carried out at a temperature of 500 to 650 degrees Celsius without or only slightly elevated pressure, Conversion per pass is maintained in the range of 20 to 50%, most often in the range of 25 to 30%, so as to maintain the linearity of the alkene chains and the double bonds are mainly in position 1.

The cleavage of the alkane chains may occur statistically, i.e. in the fubovof position, but of the resulting alkenes 85 to 90% rel. tends to be 1 alkene. The rest consists of alkenes with internal position of double bond, branched alkenes, dienes, naphthenes, and to a small extent aromatics. Of the individual higher n-alkanes, considerable attention has been paid to n-hexadecane, not only in cracking to higher 1-acenes, but also in pyrolysis to ethylene and propylene (Depeyre D. et al., Ind. Eng. Chem. Process. Des. Dev. 24, 1251 [1935]). Furthermore, tetracosan, 6-methylicosone and dodecylbenzene were confirmed and the effect of the decomposed hydrocarbon structure on the selectivity of product formation was confirmed (Blouri B. et al., Ind. Eng. Chem. Process Des. Dev. 211, 307 [1981]) . However, these methods require a technically complex preparation or isolation of n-alkanes similar to tc known (Lacko R. et al.: Oil and Coal 24, 699 [1932]) using n-alkanes C 10 to C 18 adsorbed from medium petroleum. However, the process requires energy-intensive isolation of n-alkanes from petroleum fractions, and isolation via intermediate urea adduct formation, which is mainly energy intensive, is suitable for obtaining n-alkanes above C 18.

In addition, there is a lack of suitable raw materials, paraffinic petroleum vacuum distillates, as well as the products of their subsequent physical processing.

However, these problems are solved by a process for producing 1-alkenes Cs to C 18 mainly from saturated hydrocarbons by thermal cracking at 500 to 700 ° C, preferably in the presence of water vapor in an amount of 5 to 200 wt%. to a hydrocarbon feed followed by separation of the individual fractions, preferably by recirculation of the unconverted hydrocarbons, by thermally cracking a hydrocarbon mixture of the C9 to C50 range obtained by hydrocracking the petroleum fractions, preferably the vacuum distillates of paraffinic grains and / or their products; Slack.

The advantage of the process according to the invention is the raw material availability, the expansion of the raw material base, the immediate use of fractions above 180 ° C, in particular above 300 ° C from the hydrocracking products for thermal cracking. There is no need for energy-intensive isolation of n-alkanes from petroleum fractions, whether via intermediate urea adducts or adsorption on zeolites with subsequent desorption. The alkene extracts 1 from the cracking of the hydrocracking fractions are practically similar to those of the n-alkanes themselves. Another advantage is the evaluation of hydrocracking products not only for the production of gaseous (propane, hutane, isobutane and others) and liquid (gasoline, kerosene, diesel) fuels, but also petrochemically for the production of higher l-alkenes. These, unlike those prepared by cracking solid paratins or slacks as from the 11-alkanes obtained by isolation via urea adducts, are generally not required! subsequent refining.

Cracking of higher fractions of hydrocracking products with higher production targets of 1-alkenes is advisable! in the presence of water vapor not only. from heat supply for endothermic cracking reactions, but also for preventing or at least substantial retarding of coke. The residence time is usually in the range of 1 to 15 s, but from the point of view of one-pass cracking conversion, but in particular selectivity to 1-alkenes and the prevention of subsequent reactions, it has a suitable residence time of 2 to 4 s.

Separation of the individual fractions of cracking is accomplished by known methods and procedures such as distillation, rectification, extraction, crystallization with extraction. Insulation. unsaturated hydrocarbons, in particular higher alkenes, and, in particular, 1-alkanes from alkanes and other hydrocarbons with an overlapping rz boiling point, are made by crystallization associated with the extraction (Sherbina Ε.I. and others: So-called College Introduction) neft i gaz, 1973, C. -1, p. 61; CAA. author's certificate 179 674 and 203 457; GDR pat. 124 800; Macho V., Žiak J .: Chem. Avg. 29, 249 [1979]), adsorption and desorption on zeolites (U.S. Pat. No. 3,733,361), chemisorption followed by desorption on metal compounds of the first group of the periodic system and the like.

For the production of Co-Cra 1-alkenes, it is possible, on the one hand, to take the whole mixture of hydrocarbons C 1 to C 50 from the hydrocracking products and, on the other hand, the narrower fractions of this range. Since the aim is to produce mainly the 1-alkenes C11 to C10, the fraction from the hydrocracking product above 280, respectively, is most suitable. up to above 350 ° C.

Vacuum distillates, especially paraffinic vacuum distillates, are suitable as hydrocracking feedstocks for the production of suitable thermal cracking products to produce higher l-alkenes. Further, the products of their post-treatment physics, such as paraffin slacks and the like. Similarly, residual fractions of petroleum distillation - black oil may be used according to the invention, especially for praffinic oil black oil, but this is less suitable than in the case of vacuum distillates.

Other advantages of the method of the present invention as well as a further detailed description thereof are apparent from the examples.

Example 1

In a flow-through high-pressure apparatus, the crude oil distillate is hydrocracked at a temperature of 410 + 3 ° C, a pressure of 11.3 MPa, a flow rate of 1.6 h ¹ on a Ni-Mo catalyst / amorphous alumosilicate. The hydrocracking reaction product obtained is fractionated, the fraction having a boiling point of 200-350 ° C having the following characteristics: average molecular weight - 232.4 g. mol · ¹ ; density at 20 ° C = 793.1 kg. mu ³ ; n-alkanes content (% by weight) n-Cn = 0.30; 11-C12 = - 1.38; n-C 18 = 3.36; n-Cw = 4.90; n-C 18 - - 6.50; n-C 10 = 8.41; n-C 17 = 7.98; n-C18 = -8.78; n-C 19 = 8.23; n-C 20 = 6.78; n-Csi =

4.01; n-C22 ~ 0.94, m.p. j. overall, the fraction is 61.44 wt. n-alkanes, with the remainder to 100% being mainly branched alkanes and alkylcycloalkanes.

The hydrocracking product fraction boiling at 200-350 ° C is thermally cracked in a stainless steel flow tube refractor at 580 + 4 ° C, a water vapor / feed weight ratio of - 0.2 and a residence time of - - 3.3 s, the feedstock conversion being 22.3% by weight per pass; yield of Cs to C20 alkenes = 15.5 wt. and yield of 1-alkenes Cs to C20 = 14.25 wt. The distribution of 1-alkenes Cs to C20 (in%) is as follows: Cs - 11.30; C6 ~ 14.32; C7 - --- 8.98; CI = 6.39; C9 = 6.10; C10 = 6.67; Cit = 6.32; C12 - = 7.02; C13 = 8.23; C 14 = 7.37; C15 = 5.33; Cle = 4.28; C17 = 3.72; C13 == 2.32; C19 = 0.98; C20 = 0.56.

The hydrocarbon fraction C5 to C10 is separated by rectification 11a of a column of theoretical degrees 20 and a reflux ratio of 5: 1, whereby and the tissues from this fraction are separated by adsorption and desorption on zeolites (U.S. Pat. No. 3733261), respectively. by chemisorption on active carbon impregnated with copper acetate. The C11-C10 alkenes are isolated from the saturated hydrocarbon mixture (overlapping temperatures) by low temperature acetone extraction by adding twice as much acetone to the hydrocarbon mixture and cooling the mixture to -15 ° C. A solid phase is formed which is filtered off and the liquid phase is distilled. After separation of acetone, a mixture of Cs to C20 alkenes having a concentration of 92 wt.

”R 1 and d 2

The hydrocarbon fraction boiling above 360 ° C obtained from the hydrocracking product of the vacuum oil distillates mentioned in Example 1 has an average molecular weight of 406 g. mol ^-1 and a density at 20 ° C of 859.9 kg. . m ^_3 . It consists of 96,4% wt. % of alkanocyclanes, 1.5 wt. monoaromatics, 1.6 wt. biaromates, the remainder being higher molecular weight and unidentifiable compounds. Structural type analysis by NMR shows that the number of naphthenic rings in the alkyl substituents = 1.09; the average number of carbons in the alkyl7 substituents = 19.8; aromatic carbons = 0.8; the number of alkyl spupins in the average molecule - 1.46 and the number of naphthenic rings in the average molecule = 1.59.

Thermal cracking of a fraction boiling above 360 ° C as feedstock at 620 + 5 ^e C, a water to feedstock weight ratio of 0.50 and a residence time of 1.32 s, yields a liquid fraction of 75% by weight. wherein the yield of 1-alkenes Cs to C22 per feed is 17.81 wt%.

The distribution of the Cs-G22 1-alkenes in the product is as follows: (in wt.%) Cs-12.97; Cs - = 15.22; C7 = 13.03; Cs = 8.48; Cs = 7.47; C10 = 7.47; Cu = 5.95; C12 = 4.60; C: ₃ == 4.72; C 14 = 5.28; Cis = 3.76; Cl6 = 3.14; C17 = 2.47; C18 = 2.02; Cia = 1.40; C23 = 0.95; C21 = 0.62 and C22 = 0. -45.

The fraction having a boiling point of up to 200 ° C is separated by rectification, further under reduced pressure (2.67 kPaj at atmospheric pressure), a fraction of 200 to 320 ^° C, from which alkenes are isolated by extraction of acetone at 0 ° C. with a boiling point of 200 DEG-320 DEG C. containing 89% by weight of alkenes, of which 79.6% by weight are 1-alkenes.

The C10-C17 11-alkane mixture is thermally cracked to compare the formation of 1-alkenes by thermal cleavage of the hydrocracking products. The C10-C17 n-alkanes originate from adsorption dealcanization on zeolites from medium petroleum fractions. The C10-C17 n-alkane mixture has a density of 755.0 kg at 20 ° C. m- ³ and an average molar mass of 226.4 g. mol ' ¹ . The mixture of n-alkanes has the following composition (in% by weight): n-C10 = 6.15; n-Cl1 = 28.40; n-Cl2 = 28.69; n-C 18 = 33.09; n-C14 = 1.67; n-C 18 = 1.19; n-C18 = 0.60; and n-C 17 = 0.29.

Thermal cracking of this mixture of n-alkanes at a temperature of 580 + 4 ° C and a weight ratio of water vapor to n-alkane mixture of 0.20, a residence time of 3.72 sec.

36.80 wt.%, The total yield of unsaturated C5 to C14 hydrocarbons being

17.3 wt.%, Of which 15.51 wt. they are 1-alkenes of C 5 to C 14. The distribution of the Cs-C14 1-alkenes in the product is as follows (in the pen): Cs = 12.27; Cs = 19.82; C7 = 21.37; Ca = 15.75; C9 = 15.24; C10 == 9.88; C11 = 4.91; C12 = 0.26; C13 = 0.39; C 14 = 0.13.

Under otherwise similar conditions, but with a residence time of 3.3 s, which is comparable to that of the cracking fraction of 200-360 degrees Celsius of the hydrocracking products (Example 1), a conversion of 26.24% by weight is achieved per pass through the reactor. the yield of the C3-C16 alkenes reaches 11.75% by weight, of which 10.80% by weight. the 1-alkenes are C5-C16.

Claims (1)

substituents -19.8; aromatic fraction = 0.8; the number of alkyl groups in the average molecule - 1.46 and the number of naphthenic rings in the average molecule = 1.59. By thermal cracking of the fraction with a temperature above 360 ° C as a raw material at 620 + 5 eC, a water to raw material weight ratio of 0.50 and a residence time of 1.32 s, a yield of 75% by weight is obtained. wherein the yield of 1-alkenes of Cs to C22 is 17.81% by weight. The distribution of 1-alkenes of Cs to G22 in the product is as follows: (in wt%) Cs-12.97; Cs-= 15.22; C7 = 13.03; Cs = 8.4; Cs = 7.47, C10 = 7.47; C11 = 5.95; C12 = 4.60; C: 3 = = 4.72; C 14 = 5.28; C 18 = 3.76; C16 = 3.14, C17 = 2.47; C 18 = 2.02; C19 = 1.40; C23 = 0.95; C21 = 0.62 and C22 = 0.45. Rectification separates the fraction to 200 ° C, further under reduced pressure (2.67 kPa measured at atmospheric pressure, fraction 200 to 320 CC, from which the alkenes are isolated by extraction of acetone at 0 ° C to give a boiling fraction). Example 3 A mixture of n-alkanes C10 to C17 is thermiccracked to compare the formation of 1-alkanes by thermal cleavage, from 200 to 320 ° C, containing 89% by weight of alkenes, of which 79.6% is 1-alkene. n-alkanes C10 to C17 are derived from adsorption dealkation on medium oil fractions zeolites.The mixture of n-alkanes C10 to C17 has a density of 755.0 kg / m 3 at 20 ° C and an average molar mass of 226.4 g mol -1 The n-alkane mixture of this composition (in wt%): n-C10 = 6.15, n-Cl1 = 28.40, n-Cl2 = 28.69; N-C 17 = 1.19, n-C 16 = 0.60, and n-C 17 = 0.29, by thermal cracking of this n-alkanes mixture at 580 ° C; + 4 ° C and water weight ratio of vapor to a mixture of n-alkanes of 0.20, a residence time of 3.72 s, a conversion of n-alkanes of 36.80% by weight is achieved in a single pass reactor, with a total yield of non-saturated C8 to C14 hydrocarbons being 17.3% by weight; of which 15.51 wt. forming 1-alkenes of C 5 to C 14. The distribution of 1-alkenes of C 5 to C 14 in the product is as follows (for example): Cs = 12.27; Cs = 19.82; C7 = 21.37, Cs = 15.75; C9 = 15.24; C10 = 9.88; C11 = 4.91; C12 = 0.26; C13 = 0.39; C 14 = 0.13. Under otherwise similar conditions, but a holding time of 3.3 s, which is comparable to the cracking time of the fraction of 200-360 degrees Celsius of the hydrocracking products (Example 1), a conversion of 26.24 wt. the total yield of C5 to C16 alkenes is 11.75% by weight, of which 10.80% by weight. form 1-alkenes of C 5 to C 18. SUBSTITUTE Preparation of 1-alkenes of C6 to C18 mainly from saturated hydrocarbons by thermal cracking at 500 to 700 ° C, preferably in the presence of water vapor in an amount of 5 to 200% by weight. to a hydrocarbon feed, followed by separation of the individual fractions, preferably with recirculation of the converted hydrocarbons, characterized in that the mixture of hydrocarbons from the range of Ca to C50 is thermally cracked, obtained by hydro-cracking of the petroleum fractions, preferably the paraffinic distillates. and / or their physical processing products, preferably slivers. Severografia, n. P zvod 7, Most Price 2,40 Kcs