RU2644869C2 - Synthetic gas production method - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is referred to production processes of synthetic gas by hydrocarbon conversion, and namely to processes of oxidative conversion. Method for producing synthetic gas is based on burning a mixture of a hydrocarbon feed with an oxidizing agent within one or more cavities, formed by a material that is permeable to a mixture of a hydrocarbon feed with an oxidizer, onto the inner surface of which a catalytically active component is applied. Resulting synthetic gas can be used in chemical industry for production of methanol, dimethyl ether, synthetic liquid hydrocarbons and other products. Resulting hydrogen after its separation from the gas mixture can be used to power the fuel cells of vehicles and autonomous power supplies, as well it can be used as a raw material and a reducing agent in chemical, petrochemical, metallurgical and in other industries.

EFFECT: technical effect: increase in the yield of synthetic gas and decrease in the content of hydrocarbons in the resulting synthetic gas.

1 cl, 10 ex

Description

The invention relates to processes for producing synthesis gas by conversion of hydrocarbons, and in particular to processes of oxidative conversion. The resulting synthesis gas can be used in the chemical industry for the production of methanol, dimethyl ether, synthetic liquid hydrocarbons and other products. The hydrogen obtained after its separation from the gas mixture can be used to power the fuel cells of vehicles and autonomous power sources, as well as raw materials and reducing agents in the chemical, petrochemical, metallurgical and other industries.

The main industrial methods for producing synthesis gas at present are steam, vapor-oxygen and autothermal reforming of natural gas or coal. If industrial production of hydrogen is necessary, it is isolated by various methods from the obtained synthesis gas (a mixture of H ₂ and CO). An additional amount of hydrogen is obtained by converting CO in the presence of water vapor into hydrogen and CO ₂ . These methods require the use of expensive catalysts and are characterized by high complexity and cumbersome equipment, large specific capital costs, which makes them unsuitable for creating small autonomous sources of synthesis gas and hydrogen.

A known method of producing synthesis gas during combustion, described in the patent of the Russian Federation No. 2320531, C01B 3/36, B01J 7/00, publ. 03/27/2008. The combustion of a mixture of hydrocarbon feedstocks and an oxidizing agent taken in a ratio corresponding to an excess ratio of an oxidizing agent of less than 1 is carried out in a turbulent flow-through reactor in a turbulent mode. In addition to this mixture, superheated water vapor is supplied to the reaction zone in an amount of 5-20 wt.% With respect to the supplied carbon (in the form of hydrocarbon feed). Ignition of a three-component mixture in the first combustion chamber is carried out by a stream of hot gas from an external source, the pressure of which during the ignition is higher than the pressure in the first reactor chamber. The combustion products from the first reactor chamber through a nozzle with a critical pressure drop are sent to the second chamber and the process is continued until the oxygen content in the combustion products is not more than 0.3 vol.%. Get synthesis gas in which the volume ratio of H ₂ / CO≈2.0.

The disadvantage of this method is the complexity of the process: firstly, a stable combustion mode is maintained by a stream of hot gas from an additional external source, and secondly, to prevent soot formation and achieve the desired ratio of H ₂ and CO in the resulting synthesis gas, a large amount of water steam to the reaction zone. The device for implementing the prototype method is also of high complexity - the reactor is designed as a two-chamber jet engine with high heat stress in the combustion chamber, which requires the use of special structural materials and complex cooling methods.

Closest to the proposed method for producing synthesis gas is the method described in the patent of the Russian Federation No. 2374173, publ. 11/27/2009, priority of 06/17/08 (prototype method). The conversion of a mixture of hydrocarbon feedstocks with an oxidizing agent with an excess coefficient of oxidizing agent of less than 1 is carried out at a temperature of less than 1100 ° C inside one or more cavities formed completely or partially by a material permeable to a mixture of hydrocarbon feedstocks with an oxidizing agent, and the mixture of hydrocarbon feedstocks with an oxidizing agent is introduced through a permeable bottom cavity / cavities, or through the permeable walls of the cavity / cavities, or through the permeable walls and the bottom of the cavity / cavities, and the output of the combustion products through the upper section of the floor STI / cavities.

The disadvantages of the prototype method are the impossibility of achieving sufficiently low values of the excess coefficient of the oxidizing agent, optimal for producing synthesis gas, and insufficiently complete conversion of hydrocarbon raw materials, which leads to a decrease in the yield of synthesis gas and a high content of unreacted hydrocarbons, primarily methane, in the resulting synthesis gas.

The objective of the invention is to develop such a method for producing synthesis gas, which will provide the ability to achieve lower values of the coefficient of excess oxidizing agent and a more complete conversion of hydrocarbon raw materials, and, as a result, increase the yield of synthesis gas and reduce the content of hydrocarbons in the resulting synthesis gas.

The solution of this problem is achieved by the proposed method for producing synthesis gas by burning a mixture of hydrocarbon feed with an oxidizing agent with a molar ratio of hydrocarbon feed to the oxidizing agent less than 1 at a temperature of less than 1100 ° C inside one or more cavities formed by a material permeable to a mixture of hydrocarbon feed with an oxidizing agent in that a aluminosilicate ceramic plate with a layer of alumina modified with lanthanum oxide is used as the permeable material of the cavity with a pore size of 1-1000 μm, on the inner surface of which is applied a catalytically active component selected from metals of group VIII of Ni, Pd, Pt, Fe, Co with a concentration in the range of 0.03-10 wt.% based on the weight of the permeable material.

The catalysts were prepared by co-impregnating the carrier in terms of moisture capacity with an aqueous solution of the initial metal-containing salt. As starting salts of the corresponding metals were used:

 nickel nitrate hexahydrate Ni (NO ₃ ) ₂ ⋅ 6H ₂ O  hydrochloric platinum chloride H ₂ PtCl ₆  palladium hydrochloric acid H ₂ PdCl ₆

The calculation of the amount of the initial salt required for the preparation of the catalyst containing n, wt.%, The active component was carried out as follows:

- determination of the mass of metal (m _Me ):

where m of the _medium is the mass of the medium used;

- calculation of the mass of a metal salt (m _salt ) required for the introduction of a given mass of metal:

where M _Me is the molar mass of the metal, g / mol, M _salt is the molar mass of the corresponding salt, g / mol.

The required amount of the starting salt thus determined was dissolved in water, the volume of which was taken based on the mass of the carrier used and its moisture capacity. The resulting solution was used to impregnate the carrier.

After impregnation, the catalyst samples were dried at a temperature of 120 ° C for 3 hours.

The preliminary processing of the catalysts was carried out as follows. The samples were calcined in air and carried out for two hours at a temperature of 300 ° C, and then for another two hours at a temperature of 600 ° C and 4 hours at 900 ° C.

The proposed method was developed on the basis of detailed experimental studies of the effect of the composition and concentration of the applied catalyst on the yield and composition of the resulting synthesis gas.

The principal result of the tests conducted is the establishment of the possibility of a significant reduction in the value of the coefficient of excess oxidizing agent and increase the conversion of hydrocarbon feedstocks. The use of supported Ni-containing catalyst allowed to reduce the achieved value of the coefficient of excess oxidizing agent from a value of 0.6 to a value of 0.25. The concentration of hydrogen and carbon monoxide increased from 10 and 10% to 28 and 15%, respectively.

The advantage of the claimed solution is a higher yield of synthesis gas compared with the prototype and a lower content of unreacted hydrocarbons in the resulting synthesis gas.

Here are illustrative examples of the method:

Example 1

Permeable matrix - a round plate of perforated ceramic with a thickness of 15 mm, penetrated by cylindrical channels with a diameter of 1.2 mm.

The ratio of the total cross-sectional area of the channels to the total surface area (porosity) is γ = Sc / S = 0.25.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 683 The achieved value of the coefficient of excess oxidizer 0.43 Methane Conversion,% 88 The conversion of oxygen,% 98 The concentration of N ₂ in products,% eleven The concentration of CO in the products,% 6.7

Example 2

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 1200 microns. The applied layer has a developed surface and high thermal stability (including resistance to sintering), can serve as a good basis for the deposition of the active components of various types of catalysts. The deposited alumina layer itself has some activity in the partial oxidation of methane to synthesis gas in lean mixtures.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 821 The achieved value of the coefficient of excess oxidizer 0.59 Methane Conversion,% 95.3 The conversion of oxygen,% 96 The concentration of N ₂ in products,% 10,4 The concentration of CO in the products,% 10.5

Example 3

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 1200 microns. The applied layer has a developed surface and high thermal stability (including resistance to sintering), can serve as a good basis for the deposition of the active components of various types of catalysts. The active component Ni was applied in an amount of 2.5 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C: 821 The achieved value of the coefficient of excess oxidizer 0.56 Methane Conversion,% 96.3 The conversion of oxygen,% 96.4 The concentration of N ₂ in products,% 10.9 The concentration of CO in the products,% 10,4

Example 4

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 500 μm. The applied layer has a developed surface and high thermal stability (including resistance to sintering), can serve as a good basis for the deposition of the active components of various types of catalysts. The active component Ni was applied in an amount of 5.0 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 632 The achieved value of the coefficient of excess oxidizer 0.28 Methane Conversion,% 93.15 The conversion of oxygen,% 93.3 The concentration of N ₂ in products,% 28,4 The concentration of CO in the products,% 15.8

Example 5

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 100 microns. The applied layer has a developed surface and high thermal stability (including resistance to sintering), can serve as a good basis for the deposition of the active components of various types of catalysts. The active component Ni was applied in an amount of 10.0 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C: 615 The achieved value of the coefficient of excess oxidizer 0.25 Methane Conversion,% 90 The conversion of oxygen,% 98 The concentration of N ₂ in products,% 27 The concentration of CO in the products,% eleven

Example 6

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 1 μm. The applied layer has a developed surface and high thermal stability (including resistance to sintering), can serve as a good basis for the deposition of the active components of various types of catalysts. The active component Pt was applied in an amount of 0.03 wt. % by weight of permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 683 The achieved value of the coefficient of excess oxidizer 0.25 Methane Conversion,% 33 The conversion of oxygen,% 95 The concentration of N ₂ in products,% 5 The concentration of CO in the products,% 6

Example 7

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 10 μm. The applied layer has a developed surface and high thermal stability (including resistance to sintering), can serve as a good basis for the deposition of the active components of various types of catalysts. The active component Pd was applied in an amount of 1.0 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C: 728 The achieved value of the coefficient of excess oxidizer 0.22 Methane Conversion,% 42 The conversion of oxygen,% 86 The concentration of N ₂ in products,% 9.8 The concentration of CO in the products,% 9.9

Example 8

The permeable matrix is a porous plate made of aluminosilicate ceramic with a deposited layer of alumina modified with lanthanum oxide, pore size 1000 μm. The active component Ni was applied in an amount of 2.5 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 821 The achieved value of the coefficient of excess oxidizer 0.47 Methane Conversion,% 97.4 The conversion of oxygen,% 99,4 The concentration of N ₂ in products,% 17.3 The concentration of CO in the products,% 12,4

Example 9

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 500 μm. The active component Fe is applied in an amount of 7.0 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 603 The achieved value of the coefficient of excess oxidizer 0.43 Methane Conversion,% 98.5 The conversion of oxygen,% 97.5 The concentration of N ₂ in products,% 15.4 The concentration of CO in the products,% 12.3

Example 10

The permeable matrix is a porous plate made of aluminosilicate ceramic coated with a layer of alumina modified with lanthanum oxide, pore size 300 microns. The active component Co was applied in an amount of 2.0 wt.% By weight of the permeable material.

Convertible hydrocarbon gas - technical methane from a high-pressure tank according to TU 51-841-87:

Matrix area, cm ² 19.62 The surface temperature of the matrix, ° C 803 The achieved value of the coefficient of excess oxidizer 0.37 Methane Conversion,% 99.3 The conversion of oxygen,% 99.0 The concentration of N ₂ in products,% 19.7 The concentration of CO in the products,% 14.1

Thus, the claimed method ensures the achievement of significantly lower values of the coefficient of excess oxidizing agent during the conversion of hydrocarbon gases to synthesis gas, which, in turn, provides a higher conversion of hydrocarbon gas. As a result, higher concentrations of the target products — H ₂ and CO — were obtained with a lower content of the original hydrocarbon in the resulting synthesis gas.

Claims (1)

A method of producing synthesis gas by burning a mixture of hydrocarbons with an oxidizing agent with a molar ratio of hydrocarbons to oxidizing agents of less than 1 at a temperature of less than 1100 ° C inside one or more cavities formed by a material permeable to a mixture of hydrocarbons with an oxidizing agent, characterized in that as permeable cavity material, an aluminosilicate ceramic plate with a layer of alumina modified with lanthanum oxide, with a pore size of 1-1000 μm, is used on the inner surface of which deposited on catalytically active component selected from Group VIII metals Ni, Pd, Pt, Fe, Co at a concentration in the range 0,03-10 wt.% based on the weight of the permeable material.