CS226244B1 - Method of producing ethylene and/or acetylene - Google Patents

Description

The present invention relates to the production of ethylene and / or acetylene by high temperature pyrolysis of pl-4-loghalo-hydroxyalkyl with immediate contact of the pyrolyzed hydrocarbonaceous feedstock with a reaction heat donor using an unconventional starting material.

It is known to produce ethylene by medium-temperature pyrolysis at temperatures of not more than 750 ° C to 850 ° C in tubular pyrolysis furnaces. butane and isobutane, followed by pyrolysis of C ^-fraction, benzene-toluene-xylene fraction, aromatics up to Cq, pyrooleas and carboids. Depending on the composition of the pyrolyzed hydrocarbon feedstock and the reaction conditions, the yields of the individual components vary. The highest yields of ethylene are obtained from ethane, then from propane, butane and 1-light naphtha Yemyskaya: Chim. prom. 12 £ 8,208; Itsek, Muohina: Neftepererabotka i neftechim. no. 7, 27 (1967)] · With increasing molecular weight of the feed material falling yields of ethylene which j® ^zr ®m my particular when used separately, and atmospheric gas oil vókuového ^ Mukhina, Paul: Neftechimija 1, 382 (1961); Muohina, Le statue: Chim. Think. 1262, 80; Neftepererabotká i neftechimimija č. 7, 27 (1967); Chem. Techn. 21 (2), 97 (1969); Guccione E. Chem. Eng. 22 196 (1963)? Dutch Pat. 6,505,055; CA

11003c; Belgian Pat. 669 163 ^] · The problem of medium-temperature pyrolysis in addition to extracts of the most valuable component, i. The formation of carboids, which cause coking and thus swelling, is possible only when the pyrolysis tubes are burnt. In addition to the reaction conditions (temperature, contact time, water vapor supply, eventual hydrogen, small amounts of oxygen, coking inhibitors, etc.), the type of feedstock applied to pyrolysis, in particular the structure of pyrolyzed hydrocarbons, influences coking. Therefore, although in principle all types of hydrocarbons, except paraffins, naphthenes, aromatics, olefins and diolefins can be thermally digested - pyrolyzed [Tyoya Sakai et al. In Ref. Petroleum for Chemicals. Adwances in Chemistry series 97, American Chemical Society, p.

- 91. Washington, D.C. 1970 »Lapitskaya, Zubkova: Neftepererabotka i neftechimija, Naučno-techn. Coll. 1963 (1), 34; Oganov, Turovski: Azerb. Chim. Journal. 1965 (3), 22; Xtsek, Muchina: Neftepererab. i neftechimija 196 £ (7), 277, the highest ethylene extracts yield paraffinic hydrocarbons, while aromatics, olefins and diolefins also largely generate carboids, causing premature coking of pyrolysis tubes. Therefore, it is very strict to ensure that the feed material is as paraffinic, respectively. isoparaffinic and naphthenic. So eg. in addition to the primary pyrolysis gasoline, a suitable feed may also be reformed gasoline depleted of aromatic hydrocarbons Jkuchina, Pavlova: Neftechimija 1, 382 (1961) It is also known that the formation of coke and soot by pyrolysis can be largely prevented by keeping the walls of the reaction tubes or chambers cooler than the interior space in which pyrolysis occurs. Furthermore, it is the application of water vapor or any diluent to the pyrolysis environment where it is also a heat transfer medium. The situation is similar at high temperature j resp. oxidative pyrolysis {Linden, Reid: Petroleum Ref. 35, No. 6, 189 (1956); Braconier: Erdol and Kohle 13, 248 (1960); Kamptner: Erdol and Kohle 16: 547 (1963); Inform. Chim. 1966 (33), 16,18,21,35,43; V. Brit. pat. 876 264; 912 445;

924 491; Vasiliev, Lapides: Neftechimiya Akad. nauk Turkmen. SSR 1963,79; France. pat. 1,388,183; US Pat. No. 3,373,248 and German Pat.

169 435j, or in the diffusion flame process (U.S. Pat. No. 3,153,104), for which methane, ethane, propane, butanes, primary gasoline, optionally with water additives, are also used as feedstocks. superheated steam (U.S. Pat. No. 2,921,100) and generally oxygen (U.S. Pat. No. 945,448). High-temperature pyrolysis of hexane and light gasoline can also be carried out using an externally heated fluidized bed Fbaizo Kumi and others: Kagaku Kogaku

- 4,226,244

31, 699 (1967); C.A. 68, 61216a] · Finally, the co-production of acetylene and ethylene from a mixture of propane and butane can be carried out in plasma [valibekov: Doc. Akad. nauk TadŽ. SSR lj, (8), (1970)] However, there is also a problem with the availability of starting spreading raw materials [Green, Oil Gas 64 (51), 75 (1966)] available for the reliable production of ethylene with acetylene and the heat required for cleavage. hydrocarbons. The gas of the coke oven is also used (German Pat. No. 1,070,620), the walls of the cleavage chamber being protected by superheated steam. Thus, the gasoline fraction is cleaved by t. in. 40 to 140 ° C and methane at atmospheric pressure at a temperature of 1000 to 1500 ° C, the necessary heat being obtained by combustion with an oxidizing gas containing 98 vol. oxygen and a heating gas containing 70% vol. hydrogen, 21% v / v nitrogen and 9% vol. carbon dioxide (U.S. Pat. No. 1,943,823). A mixture of hydrocarbons consisting of:

82,3% vol. propane, 15,3% vol. butane and 2.4 vol. butenes, the flowering being done with water. It was studied on a laboratory scale without coke monitoring [Subotin, Kogan: Gaz. prom. 6, no.

12, 42 (1961)] high-temperature pyrolysis of even the butane-butylene fraction for the simultaneous production of acetylene and ethylene at a temperature of 1050 to 1400 ° C, but only at a reduced total pressure of 8 to 20 kPa, as in the case of butane and isobutane jTropsch, Egloff: Ind. Eng. Chem. 22, 1063 (1935); Tsutsumi: Petrol. Ref. 22> δ.

3, 169 (1958); J. Ghem. Soc. Jap., Ind. Chem. Sec. 61, no. 1, 23 (1958)], or up to 73% of saturated butane, propane and jflajorov ethane are present in the butane-butylene fraction, Muchina: Gaz. prom. 6, no. 12, 42 (1961); aut. certifies. USSR 137 219]. In addition, the results of the study of model hydrocarbons Jkrekeler a. others: Erd.ol und Kohle 12, 353 (1959); Wirtz, Perchold: Ibid. 1, 977 (1962)] in short-term experiments, mainly from the viewpoint of possible extracts of ethylene, acetylene and by-products not only of paraffins, isoparaffins, naphthenes, but also of olefins and aromatics. And, as in the case of medium-temperature and high-temperature pyrolysis, care is taken, in particular for the formation of carboids and especially coke pyrolysis tubes, burner

- 5,226,244 and subsequent devices, there were no other undesirable impurities in the feedstocks nor olefinic and aromatic hydrocarbons most commonly removed by hydrogenation on Group 3 metals of the Periodic System (French Pat. 1 553 772). However, this increases the technical and economic demands for the treatment of the feedstocks for pyrolysis, and it can often limit the raw material resources in general. Then, it utilizes the advantages of the known processes and solves their technical problems with the manufacturing process of the present invention.

*

According to the present invention, a process for producing ethylene and / or acetylene based on petroleum and / or synthetic hydrocarbons by high-temperature pyrolysis at a temperature of 700-3,300 ° C and a pressure of 0.03 to 0.5 MPa with immediate contact of the hydrocarbonaceous feedstock in that the feedstock for pyrolysis in an amount of 3 to 100% by weight, calculated on the total weight of the hydrocarbon feedstocks, is a mixture of hydrocarbons C 1 to C 8 with an olefin content of 30 to 95% by weight.

The advantage of the process according to the invention is its raw material flexibility, the possibility of pyrolyzing also olefinically unsaturated hydrocarbons, which may also contain dienes and even alkynes, without additional hydrogenation or refining hydrogenation. Furthermore, the fact that there is no increased formation of carboids and no increased coking of burners and other equipment, thereby achieving a long service life of the pyrolysis equipment. Last but not least, the advantage is that the process makes it possible to utilize, without any pretreatment, the pyrolysis residual C ^-fraction, i.e. the feedstock, without any pretreatment. j. pyrolysis C? -fraction after isolation of at least a substantial portion of the valuable 1,3-butadiene and 2-methylpropene, for which a higher petrochemical utilization is often absent. In addition, if desired, in addition to acetylene and ethylene, propadiene, methylacetylene, vinylacetylene and higher acetylenic hydrocarbons can also be produced with high yields.

An important prerequisite for the success of the process according to the invention is the same or better lower wall temperature of the apparatus than the temperature of the reaction medium, in particular of the pyrolysis environment itself, with immediate transfer of the necessary heat to the pyrolyzed feedstock.

226 244 by partial combustion of hydrogen, carbon monoxide and hydrocarbons, optionally also by the addition of heated water vapor, gases and the like.

The feedstock in an amount of 3 to 100 wt. of the weight of the feed hydrocarbon is a mixture of at least two hydrocarbons Cg to C _Q containing 30 to 95% by weight. olefinically unsaturated hydrocarbons, particularly suitable is the residual pyrolysis of the .alpha.-fraction, which remains after almost complete separation of the valuable 1,3-butadiene and 2-methylpropene; hydrogen or methanol conversions on special zeolites and the like. Further fractions Cg to C _Q from the products of thermal or catalytic cracking process, a pre-fractionation of visbrekingu higher hydrocarbons, and especially gas oil and heavy fuel oil.

A suitable feedstock is also the residual pyrolysis Cg-fraction, which mainly increases after isolation of valuable cyclopentadiene and isoprene. It should also be noted that dienes, acetylenic and aromatic hydrocarbons are also acceptable ingredients in the feedstock.

The remainder of the feed composition may consist of methane, gaseous saturated and unsaturated hydrocarbons, primary gasoline and reformed gasoline, and other petroleum fractions. Less suitable but useful is treated (desalinated) oil and aromatic hydrocarbon mixtures.

Further details and further advantages of the process for producing ethylene and / or acstylene according to the present invention are apparent from the examples.

Example 1

On a high-temperature pyrolysis apparatus carried out at a temperature of 1000 to 1400 ° C (meaning the final temperature of the high-temperature pyrolysis reaction after passing the gases through the reaction tube and subsequent quenching), the petroleum fraction of light straight-run gasoline of b.p.

% to 125 ° C consisting of 77 wt. % of paraffins, 22 wt. % naphthenes, 0.9 wt. % of aromatics and 0.1 wt. of olefins in addition at 11.1 t / h after previous subcooling to -21 ° C on a Cg and higher hydrocarbon scrubber from pyrolysis gas

- 7,226,244 at a pressure of 1.5 MPa. Saturated petroleum fraction, both by hydrocarbons and higher but partly also by purged products, is used for degassing (decompression) of C ₂ hydrocarbons (ethylene + acetylene) as well as other gases at -19 ° C and 0.16 MPa. After compression of the degassed petroleum feedstock to a pressure of 1.6 MPa, it is fed to high-temperature pyrolysis as feed gasoline. The composition of this feed gasoline is as follows (in wt.%): 14.4 hydrocarbons to C ^;; of which 0.95 CJ 0.27 C £; propane 0.26; propylene 2.59; isobutane 0.38; n-butane 4.73; 1-butene with isobutene 0.22; propadiene 1.12; 1,3-butadiene 1.52 and methylacetylene 2.35, with the remainder up to 100% being the light petroleum already specified.

After gasification of the feed gasoline and overheating to a temperature of at least 135 ° C, it is fed to its own pyrolysis burner. The oleolysis is a two-stage process where, in the first stage, combustion of the combustion gas with a composition of 62 vol. hydrogen, 18% v / v methane, 18% vol. of carbon monoxide and the remainder being ethylene - nitrogen - argon with pure oxygen, a plasma of at least 2600 ° C is formed into which, after the addition of steam superheated to 400 ° C, the plasma temperature is lowered to 2400 to 2600 ° C, gassed feed gasoline is added. The reaction time is of the order of 10 3 _{38 and the} reaction gases after the reaction at a temperature of 1000 to 1200 ° C are cooled by spraying the aromatic fraction, so-called. Of a light scrub oil to a temperature of about 600 ° C and a further spray of heavy boron oil at a temperature of about 250 ° C.

The gaseous products obtained after compression to a pressure of 1.5 MPa, separation of water, aromatic fractions and washing of hydrocarbons and higher are divided into acetylene-ethylene products and combustion gas, which serve as a source of reaction heat after oxidation by oxygen.

Under these conditions, the production of 2.55 t / h of acetylene and 2.95 t / h of ethylene is achieved. The heavy aromatic oil is 0.59 t / h, the heavy oil 1.2 t / h with a carhoid content of 7% by weight.

Example 2

228 244

Petroleum fraction of 30 to 125 C of Tcn naphtha at 9.3 t / h. is fed under conditions similar to those in Example 1 to the scrubber and higher hydrocarbons from the pyrolysis stream, with the addition of 1.8 t / h of residual pyrolysis C C-fraction of the following composition (in wt.%) to the feed gasoline: hydrocarbons in the C ₂ = 0.09; propane = · = 1.78; propylene = 3.87; isobutane = 7.47; n-butane = 20.72;

1-butene + isobutane = 45.1; trans-2-butene = 12.91; cis-2-butene = a and 7.78 and 1,3-butadiene = 0.16.

Thus, unlike Example 1, the composition of feed gasoline for high temperature pyrolysis is as follows (in% by weight): hydrocarbons up to = 29.9; of which to C ₂ = 0.21; propane = 0.33; propylene = 1.77; isobutane = 1.59; n-butane »9.01; 1-butene with isobutene = 9.77; trans-2-butene »3.05; cis-2-butene = 2.11; 1,3-butadiene together with methylacetylene = 2,07 *

Compared to Example 1, this also changes the composition of the feed gasoline after C 8 hydrocarbon scrubbing and higher and subsequent decompression as in Example 1 as follows (in% by weight): hydrocarbons up to C ₂ = 0.5%; propane = 0.43; propylene = 2.35; isobutane = 0.35; n-butane = 6.71; 1-butene with isobutene = 1.79; tans-2-butene =.

= 0.22; cis-2-butene = 0.30 and 1,3-butadiene with methylacetylene = = 1.77. The yield of the individual products is as follows: 2.55 t / h acetylene; 2.95 t / h ethylene; 0,59 t / h Heavy aromatic oil; 1.2 t / h of heavy aromatic oil containing 7% by weight of carboids.

Example 3

High-temperature pyrolysis, respectively. pyrolysis by medium to low temperature plasma of residual pyrolysis C 1 -fraction As specified in Example 2, hydrogen-methane plasma is performed at a temperature of 1800 ° C. It provides pyroplyn of the following composition (% by volume):

14.8% acetylene; 6.0 ethylene; 0.32 methylacetylene; 0.27 diacetylene; 0.32 vinylacetylene; 0.92 propylene; 0.13 propadiene; 0.24, - 9 226 244 butenes; 0.28 1,3-butadiene; 0.19 cyclopentadiene; 0,1 benzene;

8.6 methane; 0.24 ethane; 0.1 propane and 67.4 hydrogen.

Claims (2)

OBJECT OF THE INVENTION 226 244 Process for the production of ethylene and / or acetylene based on petroleum and / or synthetic hydrocarbons by high-temperature pyrolysis at a temperature of 700 to 3800 ° C and a pressure of 0.03 to 0.5 MPa with immediate contact of a hydrocarbonaceous feedstock with a necessary heat donor; by * The composition according to claim 1, wherein the feedstock for pyrolysis in an amount of 3 to 100% by weight, calculated on the total weight of the hydrocarbon feedstock, is a 95% by weight mixture of hydrocarbons. 2. A process for the production of ethylene characterized by satin for high temperature pyrolysis is in an amount of 3 to 100% by weight. residual pyrolysis C 1 -fraction mass. to θθ with an olefin content of 30 to and / or acetylene according to point 1, characterized in that the feedstock comprises a fraction of primary gasoline of preferably 10 to 30% by weight, with a content of n-butenes of 60 to 80%