CS236239B1 - A method of producing ethylene and acetylene - Google Patents

Abstract

Method for producing ethylene and acetylene based on natural and/or synthetic hydrocarbons by high-temperature pyrolysis at a temperature of 1,000 to 2,800 °C and a pressure of 0.03 to 0.5 MPa with direct contact of the hydrocarbon raw material with the reaction heat carrier. A mixture of primary gasoline enriched with 5 to 20 vol. % methane or methane fraction from the gas separation process is injected into the process. The methane residue in the heating gas in the 1st pyrolysis well is replaced by residual fuel gas, the excess of which is used as a substitute for natural gas or in other technological operations.

Description

-1- 23B 239

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of ethylene and acetylene by direct contact pyrolysis of a pyrolyzed feedstock 3 with a reaction heat carrier using an unconventional feedstock.

In the thermal cracking of hydrocarbon feedstock, the production of ethylene and acetylene is necessary to bring about the necessary temperatures above 1,000 * C. Since heating through the reactor walls is technically impossible to solve, the heat source is provided by the partial oxidation of the feedstock or by spraying the feedstock into the combustion gas burners. Depending on the composition of the pyrolyzed hydrocarbon feedstock and the reaction conditions, the extracts of the individual components change. the highest ethylene extracts 3a are obtained from paraffinic hydrocarbons at 40 ° C from gasoline at temperatures of about 300 ° C (Debie II.C: Crude Oil Processing, 1551). Ethylene extracts dropped by the rising molecular weight of the hydrogen feedstock (Muchi-na, Pavlova, ITeftechimija 1, 332, 1351, p. 5 505 055, CA 54 »11003 c.). In the production of acetylene from methane or higher hydrocarbons, it is important to maintain a high temperature, a very short reaction time, and a low partial pressure of acetylene (Hrušovský 15: Chemical Treatment of Hydrocarbons, 1951). Acetylene can be produced in substantial amounts from methane only above 1200 ° C, and clamping conversion of methane occurs at 1500 ° C. The one-stage process fractionation of methane for the production of acetylene (Montecati-Hydrocarbon Processing, Nov. 1955) gives a yield of 236,239 -S > The reaction conditions are: temperature 1350 - 1450 eC, pressure 450 kPaa and reaction time in the order of 10 µs. The two-stage process for the production of light petroleum and acetylene (Hoechst - Uhde: Hydro-carbon Processing, Nov. 1965) gives a yield of 50 to 54% by weight of ethylene and acetylene. When using methane as a raw material, the yield is 40% wt. acetylene. The ratio of acetylene to ethylene formed is regulated by the end temperature of the reactor and, with increasing temperature, the acetylene yield is increased to the detriment of ethylene (Shlenikov VM: Ustanovki po proizvodstvu acetilenaiz nefti i gaza 1965). zakoksovávanie zařízení.Jap. pat. 1 450 638 recommends a reaction time of about 0.001 s to prevent the formation of carbon. Furthermore, it recommends controlling the resulting combustion gases with Kg, 00, CH 2, CO 3, while there is no substantial increase in carbon formation as the temperature increases. Similarly, the situation of high-temperature pyrolysis (linden, reid: petroleum ref. 35 », 6, 139, 1955J GB, U.S. Pat. No. 876,264, 912,445, " French Pat. hSR Pat. 1,169,435.).

The technical advantages of these known processes are utilized, and the method of production of the present invention partially improves their energy problems.

According to the present invention there is provided a process for the production of ethylene and acetone based on petroleum and / or synthetic hydrocarbons by high temperature pyrolysis at a temperature of 1000 to 2800 ° C and a pressure of 0.03 to 0.5 MPa with direct heating of the hydrocarbon feedstock with heat of reaction. it is carried out in such a way that the feedstock for pyrolysis is a blend of light gasoline hydrocarbons enriched with a methane fraction dropping in the process of separation or methane to a content of 5 to 20% by volume of methane in the feedstock. The advantage of the production method of this invention is to increase the yield of Cg fraction by spraying a partial methane fraction or methane together with the gasified lightweight -3- 236 239 gasoline into the reactor burners. Subsequent loss of methane fraction as fuel in the reactors caused by conversion to acetylene is replaced with a compressed residual combustion gas mainly consisting of hydrogen, methane and carbon monoxide still burned on the firing burner. The biogas excess residual combustion gas can be used as fuel in other power plants and for other technological purposes. At the reaction time of the order of 10 [deg.] S, the increased formation of combustion gases favorably influences the formation of the Cg fraction by reducing the probability of recombination by radical formation of higher unwanted products up to coke, thus saving an aliquot portion of the water vapor needed to complete the reduction of the residual gases removed to the field burners. The advantages of the process for the production of ethylene and acetylene according to the invention are summarized in the examples: Example 1

On the high temperature pyrolysis apparatus, lightweight primary gasoline containing ca 77 wt. paraffins, ca 22 wt. naphtha, ca 0.9% wt. aromatics and ca 0.1% wt. of olefins with a desalting range of 30 DEG-120 DEG C. in an amount of 11.1 t / h, after cooling to -21 DEG C., into the gasoline separation compartment for the washing of hydrocarbons C a a and higher from the pyrolysis gas at a pressure of 1.5 MPa. The saturated hydrocarbon mixture proceeds to decompress the C 8 hydrocarbons at a temperature of -19 ° C and a pressure of 0.16 MPa. to 1.6 MPa leads to gasification and preheating to min -1-35% and the treated mixture is fed to a pyrolysis burner.

The pyrolysis process is two-stage. In the first stage, the combustion gas is composed of 62% by volume of Hg, 13% by volume of CO, 18% by volume of CH 2, 2% of nitrogen, ethylene and argon with 3% excess of combustion gas by stoichiometric amount of oxygen. with a temperature of ca 2 600 * C. By adding superheated steam to protect the burner walls, it drops to 2400 ° C, and in this second stage, gasified gasoline is added to such a combustion gas, the reaction time is in the order of 10 µs and the reaction gases at the outlet of 1 0004 1 200 Ό reactor cooled by spraying with light aromatic oil to 650 ° C and heavy oil and 250 ° C, after cooling and compressing to the gas separation department, under these conditions the production of 2.55 t / h acetylene and 2.95 t / h of ethylene, while the formation of a light aromatic oil is 0.59 t / l, the heavy oil 1.2 t / h with a content of 7% of carbides.

The gaseous primary gasoline is passed under the same conditions as in Example 1 to gasoline washing and after gasification and superheating to a temperature of min. 135 * 0 admixes a suitable compressed methane fraction from the gas separation in

About 300 llr / h. The mixture thus prepared is injected into the blast furnace gases in the second stage of pyrolysis. In the first stage, the incinerator / gas is a composition of 64% by volume Kg @ 13 / v / v, 17% v / v by volume of nitrogen, argon, ethylene prepared by mixing the combustion gas as in Example 1 depleted o chemically consumed methane fraction with residual combustion gas in the amount of 700 km / h so that a ca 5% excess of combustion gas is generated against the stoichiometric amount of oxygen required to generate heat. Reaction time and reactor end temperature remain the same as Example 1. The yield in this process is 2.62 t / hacetylene? 2.95 t / h ethylene? 0.61 t / h of light aromatic oil and 1.18 t / h of heavy oil containing ca 7% wt. karboi-dov. · 'Example 3 236 23!

The high temperature reaction of the gas mixture as in Example 2 is carried out in such a way that the end temperature of the combustion gases exiting the reactor is 1300 * 0 · The process thus conducted provides a combustion gas of composition (in% vol.) 8.97% acetylene 2.5.5% ethylene content methane remains at the same level as in Examples 1. and 2. Compared to the 1st and 2nd, the benzene content is increased to the detralkyl aromatics in liquid tars.

Claims (1)

FOREWORD II 236 239 Process for producing ethylene and acetylene based on natural and / or synthetic hydrocarbons by high-temperature pyrolysis at a temperature of 1000 to 2 800 * 0 and a pressure of 0.03 to 0.5 LOPa with direct contact of the alcohol with a reaction heat carrier, characterized in that in that pyrolysis is fed a fraction of primary light naphtha enriched with 5 to 20% by volume; methane or methane fraction from the gas separation process, with the loss of methane fraction in the combustion gases in the first stage of pyrolysis being replaced by residual combustion gas.