SU701529A3 - Method of producing ethane ano/or ethylene - Google Patents

Description

one

The invention relates to a combination of the production of ethane and / or ethylene from carbon monoxide and hydrogen.

Ethane and ethylene are multipurpose starting materials for chemical synthesis. Until now, ethane was produced mainly from natural gas and by distillation of petroleum, while ethylene is produced primarily by pyrolysis of fragrant petroleum fractions from ethane to gas oil or crude oil. In some areas, ethylene is produced by pyrolysis of oil, gasoline, or kerosene. With the depletion of natural gas and oil reserves, there is a need for new processes for the production of ethane and ethylene, which are not focused on natural gas and oil as raw materials.

The closest to the invention but the technical essence and the achieved result is a method for producing ethane and / or; n1 ethylene by reacting hydrogen and carbon monoxide at low temperatures and pressures in the presence of a Fseira Tropsch catalyst to produce a hydrocarbon containing reaction mixture.

According to this method, the catalyst used contains iron, as well as alumina, magnesia, thoria, calcium oxide, potassium oxide, silicon dioxide, titanium dioxide, molybdenum oxide, manganese oxide, or a mixture thereof 5 as promoters or activators. For example, scale and magnetite are suitable as the source of the iron component, the latter JOKC containing some of the promoters or activators.

The process is carried out at a temperature of 200-500 ° C and an elevated pressure of up to 20 atm, with a molar ratio of hydrogen and carbon monoxide of 2.7: 1. However, the yield of ethylene is negligible ..

The purpose of the invention is to increase the yield of the target product.

This goal is achieved by the described method of producing ethane and / or ethylene by reacting hydrogen and carbon monoxide at elevated temperature and pressure in the presence of a Fip / ér-Tropsch catalyst to obtain a reaction mixture containing hydrocarbons, which is pyrolyzed in the presence of hydrogen at a temperature of 799 846 ° C and a molar ratio of hydrogen and hydrocarbons from 1:30 to 1: 1, followed by the separation of the target products. It is preferable to carry out the reaction process at a temperature of 150-450 ° C, a pressure of 1-75 atm, a molar ratio of hydrogen and carbon monoxide of 1-5: 1. Distinctive features are carrying out pyrolysis in the presence of hydrogen of the reaction mixture at a temperature of 799846 C and a molar ratio of hydrogen and hydrocarbons from 1:30 to 1: 1, followed by separation of the target products. The technology of the proposed method is as follows. The main components of the feedstock for the catalytic reaction are hydrogen and carbon monoxide. A small amount of hydrogen causes a decrease in the reaction rate and the dissociation of carbon monoxide to carbon dioxide and elemental carbon. The formation of carbon is especially undesirable, since the latter is deposited within the reaction zone and on the catalyst. As a result, both heat transfer, which is of particular importance for the exothermic nature of the reaction, and catalyst activity are deteriorated. With an increase in the molar ratio of hydrogen and carbon monoxide, the reaction rate increases until it reaches a more or less constant value. When excess hydrogen is used, products with lower average molecular weight and higher saturation are generally formed. In addition, unused hydrogen must be introduced into the reaction and then separated again. Therefore, the optimum ratio of hydrogen to carbon monoxide is from 2: 1 to 4: 1. The initial mixture of hydrogen and carbon monoxide may contain other products, for example methane, higher hydrocarbons, oxidized hydrocarbons or inert products, such as nitrogen or argon. Sulfur compounds, such as hydrogen sulfide or carbon dioxide, are undesirable in the starting mixture because they deactivate the catalyst. Therefore, if the initial mixture contains such compounds of sulfur in more permissible trace amounts, the catalyst must be replaced more often than is usually required. The starting mixture for the catalytic reaction can be used, in particular, a gas-forming mixture formed during the interaction of coal with steam and oxygen, from which sulfur compounds are removed by a suitable method. This gaseous mixture mainly contains hydrogen and oxide of hydrogen, as well as methane, carbon dioxide, water, and, possibly, is discharged. hydrocarbons. If the molar ratio of hydrogen to carbon monoxide is too low, the gaseous mixture can be subjected to aqueous gas conversion. However, hydrogen may also be supplied outside. If necessary, the gaseous mixture can also be processed at various separation stages, for example, by cold precipitation in order to separate the majority (carbon monoxide, water, methane and higher hydrocarbons from the initial mixture so that it consists essentially of only hydrogen and carbon monoxide. The reaction is carried out at a temperature of from about 150 to 450 ° C. At a lower temperature, in most cases, high molecular weight products form that clog the catalyst or reaction zone. At higher temperatures Temperatures show increased formation of carbon, which also pollutes the catalyst.The optimum temperature is between 200 and 400 ° C., in particular, 230 to 350 ° C. The reaction pressure can be atmospheric However, at lower pressure, the reaction proceeds relatively slowly. high pressure can be applied, however, attention should be paid to the lining of the reactor, since it is possible to clog it and the catalyst, since at high pressures high molecular weight products are formed. Therefore, pressure is usually applied in the range of from 5 to 75 atm, preferably from 10 to 30 atm. The catalytic reaction can be carried out in a zone containing a fixed or fluidized catalyst bed (stationary or mobile). A fluid bed is generally used. The volumetric rate ranges from about 500 to 5,000, preferably from 3,000 to 10,000 units, the volume of the initial mixture per unit volume of catalyst per hour at standard temperatures and pressures. As a catalyst for the catalytic reaction, any iron, cobalt, nickel or ruthenium-containing Fischer-Tropsch synthesis catalysts are suitable. These catalysts are known and described. They can be used with various carrier materials, promoters or activators. The catalytic reaction is carried out under these conditions to a degree of excess of carbon monoxide contained in the initial mixture in an amount of not less than 50%, and the reaction mixture contains about 8-75 vol. Methane calculated on the total hydrocarbon content in the oxidized hydrocarbons formed on the oxide. carbon. The reaction mixture contains 25-92% vol. Total hydrocarbons and oxidized hydrocarbons. These hydrocarbons contain only minor amounts of aromatic components. Due to heavy catalyst contamination, the resulting reaction mixture contains at least 8 vol.% Methane. It is desirable that the reaction mixture contains 10-50 vol.% Methane, in particular 10 25 vol. %, based on the total content of carbon dioxide and oxidized hydrocarbons obtained from carbon monoxide. Along with hydrocarbons and oxidized hydrocarbons, the reaction mixture contains carbon monoxide, hydrogen, carbon dioxide and water. Hydrogen is contained in significant quantities, usually in quantities of more than 1 mol of hydrogen per 1 mol of hydrocarbons and oxidized hydrocarbons Cj or with a large number of carbon atoms (Cj + hydrocarbons). This is of particular importance since, under these conditions, the reaction mixture can be directly applied to the hydropyrolysis stage, without resorting to an additional supply of hydrogen from the outside. The reaction mixture, which is withdrawn from the catalytic reaction zone, is then fed to the hydropyrolysis zone. The hydropnrolysis zone is heated so that C3 + hydrocarbons and oxidized hydrocarbons undergo pyropic cracking in the presence of hydrogen to Ci and C2 hydrocarbons. Essentially, the reaction mixture leaving the catalytic reaction zone already contains enough hydrogen and is extremely suitable for pyrblitic cracking hydrocarbons and oxidized hydrocarbons to products with a relatively high molar ratio of C-hydrocarbons and Ci-hydrocarbons, for example, 0.8 molar ratio : 1 or higher. The less hydrogen is used, the more ethane is produced compared to ethylene. The amount of hydrogen, corresponding to a ratio of more than 30: 1, does not cause a noticeable effect, except for the need to separate a large volume and recirculate hydrocarbons. Hydropyrolysis is carried out at a temperature of from 600 to 900 ° C. preferably from 700 to 850 ° C. Higher temperatures are more favorable for the formation of ethylene compared to ethane. A pressure of at least 5 atm, typically 5-100 atm, and preferably 15-30 atm, varies. Lower pressures are favorable for ethylene formation compared to ethane. The reaction time ranges from 0.1 to 60 seconds, preferably from 0.5 to 20 seconds. A shorter reaction time more favorably affects the formation of ethylene compared with ethane. Deposits in the agro-pyrolysis zone can be reduced by introducing a sulfur compound in a gaseous mixture at a low concentration, e.g. 10 ppm. This process is usually referred to as zone passivation and is carried out in most cases continuously during the entire period of operation. The use of sulfur compounds in this method has the disadvantage that it is necessary to purify hydrogen, carbon monoxide and carbon dioxide in the final mixture than can be recycled for the catalytic reaction, since sulfur is the catalyst house for Fischer-Tropsch synthesis catalysts. Water vapor may be used instead of sulfur compounds, however, in order to avoid carbon deposition, larger amounts of water are needed than sulfur compounds. Approximately 3 mol of water is used per mol of hydrocarbon of the same oxidized hydrocarbon, however, significant amounts of it can be used. Water not only prevents carbonization, but can be recycled in certain amounts for a catalytic reaction. In addition, it affects the hydropyrolysis process in favor of ethylene formation compared to ethane. Depending on the desired end product, this effect can be realized. The gaseous mixture obtained from the hydropyrolysis zone is separated in a known manner to separate} cj and Cj hydrocarbons. This is accomplished, for example, by rapidly cooling the gaseous mixture and subsequent separation using a series of low-temperature fractional distillation columns. Hydrogen is first separated along with carbon monoxide, carbon dioxide and water, and transferred to a catalytic reaction zone with preliminary separation or without further separation. Thereafter, methane is removed, which can be used as flue gas. Ethylene and ethane are separated. The remaining higher hydrocarbons, which also contain some aromatic fractions, can be discharged.

hydrogenation and may be recirculated to the hydropyrolysis zone. Before hydrogenation and recycling, aromatic fractions, like benzene and toluene, can also be separated.

Instead of the described step distillation, selective step condensation may also be used to separate the mixture. In the following examples, an experimental setup is used in which the catalytic reactor and the hydropyrolysis reactor are arranged in a row. The catalytic reactor is a circularly cooled stationary fluidized bed reactor of the NPS type. Schedul-40 of special steel 316, having a diameter of 2.54 cm and a length of 203.2 cm and equipped at the lower end with a reaction plate the mixture (porous plate) and at the upper end - the sludge zone of the NPS catalyst, having a diameter of 7.62 cm, as well as a baffle plate for the catalyst and a filter.

The hydropyrolysis reactor is an 18-gauge tube made of special steel with a diameter of 1.27 cm and a length of 71.12 cm, located in a 5.08 cm NPS tubular furnace.

Example. The initial mixture of technical hydrogen and carbon monoxide together with a small amount of argon (2% of the initial mixture as an inert standard for gas chromatographic analysis) is fed separately and in a measured amount to the mixing zone. The molar ratio of hydrogen to carbon monoxide is about 3, the hydrogen feed rate is about 16.6 L / min and the carbon monoxide feed rate is about 5.45 L / min, respectively, at standard temperature conditions and pressure. After mixing, the initial mixture is sent for purification with activated carbon in molecular sieves and then heated to a temperature of about 300 ° C.

After that, the initial mixture is fed through a distribution plate into the catalytic reactor. The reactor was charged with 344 g of a pretreated iron-containing catalyst for the synthesis according to the Fischer-Tropsch method (Armco's scale, containing 0.17% by weight of potassium in the form of potassium oxide

0.17 wt.% Calcium in the form of calcium and 3 wt.% Alumina as promoters). The initial mixture is passed through a solid fluidized catalyst with a bulk velocity of about 5100, a temperature of about 360 ° C and at a pressure of about 17 atm, with a degree of conversion of carbon monoxide of more than 98%. A sample of the reaction mixture leaving the catalytic reactor is passed through a water cooled condenser and then throttled into a collector tube. The precipitated water is collected and determined. The liquid organic phase and the gas phase are analyzed by gas chromatography.

A gaseous mixture from a catalytic reactor, in which the molar ratio of hydrogen to total hydrocarbons and oxidized hydrocarbons with 3 or more carbon atoms is about 20.4, is fed directly to the hydropyrolysis reactor, in which it is converted at about 799 ° C, pressure about 17 atm and. reaction time is of the order of 0.5 s. A sample of the reaction mixture discharged from the hydropyrolysis reactor is fed through a water-cooled condenser and then throttled into the collector pipe. The condensed water is separated and determined, while the organic liquid phase and gas phase are analyzed by gas chromatography.

The results are presented in table. one.

Table 1

Continued table. one

Note. The numbers given for the catalytic reaction refer to both the hydrocarbons and the oxidized hydrocarbons in the reaction mixture, while the numbers given for the hydropyrolysis refer only to the hydrocarbons, since all of the initially available oxidized hydrocarbons are converted to the hydropyrolysis reactor.

 C includes in this and the following tables all products of C.6 and more carbon atoms. 11 p m m e r 2. The next pass is carried out as in example 1, with the molar ratio of hydrogen to carbon monoxide in the feed mixture for the catalytic reaction being about 4, the hydrogen feed rate is 13.7 l / min and the carbon monoxide feed rate is about 3.42 / min, respectively, under standard conditions.

The catalytic reaction is carried out at a temperature of 343 ° C, a pressure in the order of 13.6 atm.

and with a volume rate of about 4200 hours before, the degree of conversion of carbon monoxide is about

98.7%. In the outgoing reaction mixture, the molar ratio of hydrogen i to the total hydrocarbons and oxidized hydrocarbons with 3 or more hydrocarbon atoms is about 32.1.

Hydropyrns are carried out at a temperature of the order of 799 ° C, a pressure of the order of 13.6 atm and a reaction time of 0.5 s.

An analysis of the gaseous mixture leaving the catalytic reaction zone or hydropyrolysis is listed in the table below. 2. Table 2 P p and m ep 3. The pass is carried out as in Example 1, with the molar ratio of hydrogen to carbon monoxide in the feed mixture for the catalytic reaction being about 3, the hydrogen feed rate being 13.3 l / min and the oxide feed rate carbon, about 4.42 l / min, respectively, under standard conditions. In addition, 300 g of an iron-containing Fischer-Tropshai synthesis catalyst consisting of scale and 3 wt.% Alumina, and 0.13 wt.% Potassium in the form of potassium oxide are used.

The catalytic reaction is carried out at a temperature of about 343 ° C, a pressure of about 13.6 atm, and a bulk velocity of dPr of measure 4. The passage is carried out as in Example 1, with the molar ratio of hydrogen to carbon monoxide in the starting mixture for The catalytic reaction is 3 molar, a hydrogen feed rate of 19.1 L / min and a carbon dioxide feed rate of 6.6 L / min, respectively, under standard conditions. 300 g of Fischer-Tropsch synthesis catalyst from Example 3 are used.

The catalytic reaction is carried out at a temperature of about 343 ° C, a pressure of about 20.4 atm, with a bulk velocity of 880 to a degree of carbon monoxide conversion of 13.6 atm and a reaction time of about 0.5 s.

The results of analyzes of gaseous mixtures from the catalytic reaction zone or hydropyrolysis are given in table. 3

Table 3

a range of 96.8%. In the outgoing gaseous mixture, the molar ratio of hydrogen to hydrocarbons and oxidized hydrocarbons with 3 or more carbon atoms is about 16.3.

The hydropyrolysis is carried out at a temperature of about 807 ° C, a pressure of about 20.4 atm and a reaction time of about 0.5 s. The gaseous mixture fed to the hydrolysis reactor contains approximately 730 parts per million of hydrogen sulfide.

The results of analyzes of gaseous mixtures leaving the catalytic reaction zone or gidropyrolysis are shown in Table. 4. ca 5900 to oiCHCM carbon conversion in the order of 97.6%. In the off-gas mixture, the molar ratio of hydrogen to total hydrocarbons and oxidized hydrocarbons with a carbon number of 3 or more is about 12.5. Hydropyrolysis is carried out at a temperature in the order of 799 ° C, a pressure in the order of EXAMPLE 5. The passage is carried out as in Example I, the molar ratio of hydrogen to carbon monoxide in the starting mixture for the catalytic reaction being about 3, the hydrogen feed rate 19.1 L / min. Carbon monoxide feed rate .6.6 L / min. JpcoTseTCTBeHHO under standard conditions. In addition, 300 g of Fischer-Troscia synthesis catalyst from example 3 is used. The catalytic reaction is carried out at a temperature of 343 ° C, pressure; 20.4 atm, with a bulk velocity of 8800 hours to a degree of conversion of carbon monoxide in the order of 96.8%. In the outgoing gaseous mixture, the molar otkoschenie hydrogen to the total hydrocarbon, hydrogen and oxidized hydrocarbons with 3 or a large number of carbon atoms was -. em is about 16.3. Hydropyrolysis is carried out at a temperature of 815 ° C, a pressure of 20.4 atm and a reaction time of about 0.5 s. To the gaseous mixture fed to the pyrolysis reactor, add 105 parts per million of hydrogen sulfide. The results of analyzes of gaseous mixtures leaving the catalytic reaction zone or hydropyrolysis are shown in Table. 5. T abl and da 5 15 PRI me R 6. The passage is carried out according to tepimer 1, and the molar ratio of hydrogen to carbon monoxide in the feed mixture for the catalytic reaction is about 3, the hydrogen feed rate is 19.9 l / missions and ckopocTb supply of carbon monoxide 6.6 l / min, respectively, under standard conditions. In addition, a Fischer-Tropsch synthesis catalyst from Example 3 is used. The catalytic reaction is carried out at a temperature, a pressure of 20.4 atm with a bulk velocity of 8900 to a degree

EXAMPLE 7 The passage is carried out as in Example 1, with the molar ratio of hydrogen to carbon monoxide in the feed mixture for the catalytic reaction being about 3, the hydrogen feed rate is 19.9 l / min and the carbon dioxide feed rate is 6.6 l / min, respectively, under standard conditions. In addition, the Fsier-Tropsch synthesis catalyst from Example 3 is used.

The catalytic reaction was carried out at a temperature of 343 ° C, a pressure of 20.4 atm and with a bulk velocity of 8800 to a degree of carbon conversion of about 96.8%. In the off-gas mixture, the molar ratio of hydrogen to total hydrocarbons and oxidized hydrocarbons with 3 or more carbon atoms is about 16.3.

Table 6

Before supplying the gaseous mixture to the hydropyrolysis zone, 3.67 ml of (liquid) heated c-hexane with

the purpose of increasing the content of C3 + hydrocarbons for pyrolysis. The molar ratio of hydrogen to total hydrocarbons and oxidized hydrocarbons with 3 or more carbon atoms is about 15.0 in this mixture.

Hydropyrolysis Is carried out at a temperature of 846 ° C, a pressure of 20.4 atm and a reaction time of 0.5 s.

To the gaseous mixture fed to the hydropyrolysis reactor, 730 ppm of hydrogen sulfide is added.

Results of analyzes of gaseous mixtures,. outgoing from the catalytic reaction zone or hydropyrolysis, are listed in tab. 7. 9 carbon monoxide levels in the order of 98.1%. In the off-gas mixture, the molar ratio of hydrogen to total hydrocarbons and oxidized hydrocarbons with 3 or more carbon atoms is about 15.9. Hydropyrolysis is carried out at a temperature of 709 ° C, a pressure of 20.4 atm and a reaction time of 0.5 s. The results of analyzes of gaseous mixtures leaving the catalytic reaction zone or hydroscolysis are given in Table. 6

Example The passage is carried out according to Example 7, and 3.33 ml of (liquid) heated kerosene are added to the gaseous mixture from the catalytic reaction zone instead of n-hexane. Kerosene has t. Kip. 190-270С and specific weight 0,82. The molar ratio of hydrogen to total hydrocarbons and o syslen-; Hydrocarbons with 3 or more carbon atoms are about 15.5 in this mixture.

tagging. This number reproduces the high hydrogen pyrolysis carried out according to Example 7, the temperature being 835 ° C and only 105 parts per milliol of hydrogen sulfide are added to the gaseous mixture.

The results of analyzes of gaseous mixtures leaving the catalytic reaction zone or hydropyrrlyse are given in Table 8.

Table 8 contains some aromatics, namely kerosene, which cannot be subjected to pyrolysis and regenerated, mainly in the form of benzene, toluene and xylene.

PRI me R 9. 50% conversion of carbon monoxide TG.

Raw materials consisting of 349 l / min of hydrogen and 340 l / min of carbon monoxide are passed through a Fischer-Tropsch reactor containing 75 g of aj catalyst. The reaction temperature is maintained at 332 ° C. and a pressure of approximately 14.06 kg / cm; The reaction product, where 51% of carbon monoxide is converted, is fed to the hydropyrolysis reactor, which is at a temperature and pressure of 13.36 kg / cm.

The products of the Fischer-Tropsch reaction and the products of the hydropyrolysis reaction are presented in gab 9.

Molar ratio

Continuation tab.

Tab. 10 and 11 show the distribution of the product at different ratios of hydrogen and carbon monoxide using the proposed method and pressure. Coking of the catalyst occurs at a 1: 1 ratio of hydrogen and carbon monoxide.

Table 10

21 70152922

Claims (2)

1. The method of producing ethane and / or ethylene pu-799-846 ° C and the molar ratio of the hydride the interaction of hydrogen and carbon monoxide and hydrocarbons from 1:30 to 1: 1 followed by elevation of the target products at elevated temperature and pressure, the presence of a catalyst Phii er-Tropsch with-5 2. Way According iT. 1, about tl and ch and you n and and with by irradiating the reaction mixture containing the carbon so that the interaction process is carried out at hydrogens, characterized by the temperature of 150-450 ° C, the pressure of 1-75 atm, that, in order to increase the yield of the target molar ratio of hydrogen and carbon monoxide, the reaction mixture is subjected to pyrolide to 1-5: 1.