A method of producing methanol

 

The invention relates to methods of producing methanol from hydrocarbon gases. A method of producing methanol includes stage desulfurization of hydrocarbon gas, the stage of synthesis gas from hydrocarbon gas in the reforming reactor, the stage of compression of the synthesis gas, the stage catalytic conversion of synthesis gas into methanol in a reactor, consisting of several catalytic reactors, including heating operation and the conversion of synthesis gas to methanol in each reactor, the operation of cooling the reaction products and separating methanol after each reactor, the operation disposed of "tail gas". In the first two traffic flow reactors reactor system, the process of methanol synthesis is carried out in the pressure range of 3.0-4.5 MPa, temperature 160-320oWith volumetric flow rates 500-10000 h-1and the last two on traffic flow reactors reactor system, the process of methanol synthesis is carried out in the pressure range 5.0 to 8.0 MPa, temperature of 160-300oWith volumetric flow rates 1000-10000 h-1. The synthesis gas is fed into the reactor system for production of methanol at a molar ratio of hydrogen to carbon monoxide in the range of 2.0 to 5:1. The steam produced in the reactor for the synthesis of methane is electricity. Part of produced methanol is used as absorbent absorption-desorption of complex plants for the concentration of carbon dioxide in the portion of the stream of tail gases directed into the reactor reforming hydrocarbon gas. Water distillation residues of distillation columns, the concentration of methanol served in the catalytic reactor water purification from methanol and purified water is sent after additional training in the reactor reforming hydrocarbon gas. The invention reduces the overall energy costs of the process. 4 C.p. f-crystals, 1 Il.

The invention relates to the field of chemical technology, energy saving processes for the production of methanol from natural gas or "tail" of hydrocarbon gases in the chemical, petrochemical, metallurgical and gas processing facilities.

More specifically the invention relates to a process for the synthesis of methanol from synthesis gas produced in the catalytic reactor steam and/or propakistani conversion of lower hydrocarbons.

In industry the methanol synthesis is usually carried out in two stages: the first stage in the tubular furnace is you who ahtna the reactor steam-oxygen conversion reacted in a tubular reactor gaseous hydrocarbons, mainly of methane. Developed processes involving the combination of these devices.

In the second stage is the actual conversion of synthesis gas to methanol. To ensure high performance industrial reactors and to organize them in the temperature fields, characterized by small temperature gradients, is implemented turbulent regime of flow of reaction gas flow or flow regime close to turbulent. Usually the conversion of the initial reactants is low and unreacted synthesis gas after separation of the methanol and the additional compression again served in the input stream of raw materials in catalytic methanol synthesis reactor.

Disadvantages of industrial technologies the following: - Significant energosafety.

- The use of expensive equipment.

- Complexity of control systems.

- High capital costs.

Significant consumption norms of raw materials.

Therefore, the cost of produced methanol is large enough and cannot be used as raw material for profitable industries for the production of motor fuels or monomers (ethylene, propylene).

Known industrial techno is a traditional industrial technologies. In the patent (US 5245110) is proposed to obtain the synthesis gas in the partial oxidation of hydrocarbons with air or oxygen-enriched air. Reducing the cost of synthesis gas is achieved due to: 1. Reduce the cost of producing oxygen-enriched air in comparison with the production of pure oxygen.

2. The use of simpler and less expensive manufacturing equipment.

3. Simplify the process control system.

In the second stage production of methanol synthesis gas with a high content of nitrogen is converted to methanol in four or six series-connected reactors with intermediate condensation of methanol after each reactor. At the outlet of the reactor block unreacted synthesis gas is fed into separation membrane unit, permeate stream which is enriched in hydrogen and depleted in nitrogen, is mixed with the synthesis gas supplied to the reactor site for production of methanol. In this process, recycling the hydrogen necessary, because only in this case, the molar ratio of hydrogen to carbon monoxide in the synthesis gas can be obtained significantly more than two. The nitrogen in the system catalytic reactor recycle the inu and is discharged into the atmosphere together with the exhaust gases of the gas turbine. In this process, natural gas and air comprimida to the adiabatic reactor partial oxidation of natural gas and the resulting synthesis gas at a pressure greater than 7.0 MPa, is sent to the reactor site for methanol synthesis, in which other compressors are not used. Thus, in this process, methanol synthesis is carried out with a single initial pressure.

Processes with the same initial pressure are implemented not only for BasicInstallation on synthesis gas of industrial plants, but also for industrial installations which provide for the circulation of unreacted in the reactor for the synthesis of methanol from synthesis gas (U.S. Pat. US 4910228). In this case, natural gas is subjected to steam reforming in a catalytic reactor, compremised to pressure, which provides the pressure of the synthesis gas above the gas pressure in the circuit. The heat flux required to maintain the reactor catalytic reforming, is available due to partial oxidation of the natural gas. The power required for compression of the feedstock, oxygen, operation of the circulation path is provided by the heat of combustion of the purge circulating is a method of producing methanol, including the stage of synthesis gas production, the stage catalytic conversion of synthesis gas into methanol, including the feeding and heating the synthesis gas in the inlet zone of the reactor, the catalytic conversion of synthesis gas to methanol with heating gas flow due to the heat of reaction for methanol synthesis, the allocation of methanol and recycling tail gas. The production of methanol is carried out in several reactors in the temperature range 170-280oC, a pressure of 3.0 to 8.0 MPa and flow rate 500-10000 h-1(EN 21523578).

The disadvantages of the known methods of production of methanol from natural gas and "tail" of hydrocarbon gases in the chemical, petrochemical, gas processing facilities on BasicInstallation technologies for hydrocarbon raw materials are: - low quality of the target product; significant energy consumption in distillation of methanol; - strong deactivation of the catalysts in the reactors for methanol synthesis; - significant energy consumption in the processing of natural gas marginal gas fields.

The above disadvantages of the considered technologies hinder their direct use in the organization of industrial production of methane is the tasks: achieving high performance in the production of methanol from natural gas, obtaining the target product, methanol of high quality, a reduction in the degree of deactivation of the catalysts for long-term operation of an industrial installation, the reliability of industrial plants with the composition of the raw materials.

Resolution objectives are achieved: a Method of producing methanol, comprising the stage of desulfurization of hydrocarbon gas, the stage of synthesis gas from hydrocarbon gas in the reforming reactor, the stage of compression of the synthesis gas, the stage catalytic conversion of synthesis gas into methanol in a reactor, consisting of several catalytic reactors, including heating operation and the conversion of synthesis gas to methanol in each reactor, the operation of cooling the reaction products and separating methanol after each reactor, the operation of recycling tail gas. In the first two traffic flow reactors reactor system, the process of methanol synthesis is carried out in the pressure range of 3.0-4.5 MPa, temperature 160-320oWith volumetric flow rates 500-10000 h-1and the last two on traffic flow reactors reactor system, the process of methanol synthesis is carried out in the pressure range 5.0 to 8.0 MPa, temperature of 160-300oWith volumetric flow rates onside carbon in the range from 2.0:1 to 5:1.

The steam produced in the reactor for methanol synthesis and steam generated "smoke" gas reforming reactor is sent to a steam turbine to generate electricity.

Part of produced methanol is used as absorbent absorption-desorption of complex plants for the concentration of carbon dioxide in the portion of the stream of tail gases directed into the reactor reforming hydrocarbon gas.

Water distillation residues of distillation columns, the concentration of methanol served in the catalytic reactor water purification from methanol and purified water is sent after additional training in the reactor reforming hydrocarbon gas.

The drawing illustrates the essence of the invention, which involves the use of an industrial plant producing methanol, comprising reactor 4 lower conversion of hydrocarbons to methane, the reactor of unit 2 desulfurization of natural gas, the reforming reactor 6 natural gas into synthesis gas reactor 12, 17, 23, 28 synthesis of methanol from synthesis gas reactor 37 cleaning VAT residue column 36 from methanol rectification columns 35, 36 for the purification of methanol, column absorption of carbon dioxide 32, columns 13, 16, 18, 22, 24, 27, 29, compressors for compressing the synthesis gas 10, 21, a steam drum for steam condensation 15, 20, 26, 31.

A method of producing methanol from hydrocarbon gas is being implemented with the system shown in the drawing, as follows. The original hydrocarbon, in particular natural gas heated flue gases of the reactor reforming of methane and fed into the desulfurization unit. It is the hydrogenolysis of serosoderjaschei compounds and adsorption of the formed hydrogen sulfide to oxide-zinc sinks. Then the purified natural gas is fed into the reactor pre-reforming, in which the hydrocarbons2-C4converted to methane. Further purified natural gas mixed with water vapor. The mixture of water vapor and methane has a molar ratio in the range from 1.8 to 2.7. To this mixture is added to the carbon dioxide supplied from the absorption-desorption unit 32, 33. The resulting gas is fed into the reactor reforming of methane, which is at low pressure (0.7 to 2.9 MPa) and a temperature of 850-900oSince it is converted into synthesis gas. The synthesis gas is cooled in the heat exchangers 7, 8 and in the separator 9 is separated from it by water. Next, the synthesis gas with a residual water content less than 0.1 wt.% Postup in the heat exchanger 11, in which it is heated product stream of the reactor 12 to the reaction temperature for production of methanol. After the heat exchanger 11 synthesis gas is directed into the reaction zone of the reactor 12 in which the reaction occurs the conversion of synthesis gas to methanol. At the entrance of the reaction zone of the reactor 12 original reactants are heated boiling in the annular space of the reactor 12 coolant. In the main part of the reaction zone of the reactor 12, the heating of the reaction mixture is carried out as a result of exothermic chemical reactions of steam reforming of carbon monoxide and hydrogenation of oxide and carbon dioxide with hydrogen. However, due to intensive heat exchange between the reaction stream and cooled significant temperature gradients in the reaction zone does not occur. Next, the gas flow through the cooler-condenser 13 is supplied to the separator 14, in which the condensation of methanol. Non-condensable reaction products through the heat exchanger 16 is directed into the reactor 17. The operating conditions of the reactors 12 and 17 are identical. Non-condensable gases after the separator 19 is fed to the suction side of the compressor 21 in which they comprimida to a pressure of 7.0 MPa. Next, the synthesis gas is fed into the heat exchanger 22, where negnevitsky heat exchanger 22, the synthesis gas is sent into the reactor 23, in the entrance area which it is heated to the reaction temperature. Then the synthesis gas is fed into the main reaction zone in the reactor 23. It runs the conversion of synthesis gas to methanol. In the entrance zone of the synthesis gas is heated boiling in the annular space of the coolant and the primary catalytic zone, it cools them. From the reactor 23 product stream passes through the heat exchanger 22, where it heats the feedstock to a temperature close to the temperature of the beginning of the reaction. Next, the gas stream passes through a cooler-condenser 24 to the separator 25 where is the condensation of methanol. Neskondensirovannyh gases are directed into the heat exchanger 27 and then in the input zone of the reactor 28. The operating conditions of the reactor 28 is similar to the operating conditions of the reactor 23. From the separators 14, 19, 25, 30 the collected methanol one stream is directed into an absorption-desorption unit concentration of carbon dioxide. In the absorber 32 at an ambient temperature of the absorbent - methanol saturated with carbon dioxide, and desorber 33 is an increase in the concentration of carbon dioxide in the tail gas and catalytic reactors. They then arrive at the preparation unit gas reforming. In the vessel 34 is going absoul, consisting of two columns 35, 36. On top of the column 36 is selected commodity product, and CBM product of the column 36, which are a mixture of methanol and water (with a low content of methanol) is supplied into the reactor 37, in which the catalytic purification of water from methanol. Grocery flow reactor 37 after the secondary demineralization fed into the reactor reforming of methane 6.

Steam produced in the catalytic reactor 12, 17, 23, 28, after additional heat of its combustion gases fed to the steam turbine to produce electricity.

Therefore, the physico-chemical meaning of the present invention is that the process of methanol synthesis is carried out at a given pressure distribution on catalytic reactors with intermediate separation of methanol after each reactor. This organization catalytic process allows, firstly, high performance equipment to provide high purity methanol, which gives the opportunity to reduce energy costs in the process of rectification of methanol. Secondly, dramatically reduces the overall energy costs of carrying out catalytic synthesis process, as the total volumetric rate of flow of the e part of the original thread, and not the original raw gas stream, as in the organization of traditional industrial processes.

Example 1. Natural gas at a pressure of 0.9 MPa, after preheating the exhaust gas catalytic reformer enters the desulfurization reactor 2, in which the presence of small amounts of hydrogen at T=450oIs the hydrogenolysis of serosoderjaschei organic compounds. Then the gas stream 2 through the heat exchanger 3 is sent to the adsorber 4, in which zinc sinks is the chemisorption of hydrogen sulfide. Further natural gas with a bulk velocity 9582,2 nm3/h enters the saturator, in which it is saturated with water vapor in the number 15648 kg/hour, a Mixture of natural gas and steam is heated to a temperature of 750oC and at a pressure of 0.9 MPa enters the catalytic reactor steam reforming of methane which at a temperature of 820-950oWith the formed synthesis gas. The volumetric rate of the synthesis gas 45460 nm3/H. Then it is cooled in the heat exchangers 7, 8 and in the separator 9 is condensation of water. The dried synthesis gas with a bulk velocity 36262,2 nm3/h enters the compressor 10, in which he compremised to a pressure of 4.0 MPa. After the compressor 10 synthesis gas is Intesa methanol. After the heat exchanger 11 synthesis gas is directed into the reaction zone of the reactor 12 in which the reaction occurs the formation of methanol. At the entrance to the 12 original reactants are heated boiling in the annular space of the coolant. Due to intensive heat exchange between the reaction stream and cooled significant gradients in the reaction zone does not occur. Next, the gaseous product stream through a cooler-condenser 13 is supplied to the separator 14, in which the condensation of methanol. Produced 1765 kg/h of methanol. Composition: 92,86 wt.% methanol, 7,14 wt.% water. Non-condensable reaction products through the heat exchanger 16 is directed into the reactor 17. The operating conditions of the reactors 12 and 17 are identical. In the reactor 17 is received 1367,9 kg/h of methanol. Composition: 96,6 wt.% methanol, 3.4 wt.% water. Non-condensable gases after the separator 19 is fed to the suction side of the compressor 21 in which they comprimida to a pressure of 7.0 MPa. While the volumetric rate of the synthesis gas 29387 nm3/h, the composition of the synthesis gas: methane - 7,44% vol., hydrogen - 73,47 about. %, carbon dioxide - 7,15% vol., the carbon monoxide - to 12.44%, methanol - 0,11% After the heat exchanger 22, the synthesis gas is sent into the reactor 23, in the entrance area which it is heated to a temperature reacts the 3 is formed 2653,2 kg/h of methanol. Composition: methanol 95,0 wt.%, water 5.0 wt.% Next, the gas stream passes through a cooler-condenser 24 to the separator 25, which is the condensation of methanol. Non-condensable gases (vhsv - 25170,9 nm3/h, the composition of the gas: methane - 7,44% vol., hydrogen - 73,47% vol., carbon dioxide 7,15% vol., the carbon monoxide - to 12.44% vol.) forwarded to the heat exchanger 27 and then in the input zone of the reactor 28. The operating conditions of the reactor 28 is similar to the operating conditions of the reactor 23. In the reactor 28 is produced 1752,9 kg/h of methanol. Composition: 86,4 wt.% methanol, to 13.6 wt.% water. From the separators 14, 19, 25, 30 the collected methanol in the amount of 7546,4 kg/h goes into the General collection. The composition of the obtained methanol: 93,82 wt.% methanol, between 6.08 wt.% water.

Example 2. Natural gas at a pressure of 0.9 MPa, after preheating the exhaust gas catalytic reformer enters the desulfurization reactor 2, in which the presence of small amounts of hydrogen at T= 450oIs the hydrogenolysis of serosoderjaschei organic compounds. Then the gas stream 2 through the heat exchanger 3 is sent to the adsorber 4, in which zinc sinks is the chemisorption of hydrogen sulfide. Further natural gas with a bulk velocity 9582,2 nm3/h of carbon dioxide extracted from the exhaust gas catalytic reactors in the absorption-desorption unit sections. The mixture of natural gas, steam, and carbon dioxide is heated to a temperature of 750oC and at a pressure of 0.9 MPa enters the catalytic reactor reforming of methane which at a temperature of 820-950oWith the formed synthesis gas. He further cooled in heat exchangers 7, 8 and in the separator 9 is condensation of water. The dried synthesis gas with a bulk velocity 32475,0 nm3/h enters the compressor 10, in which he compremised to a pressure of 3.0 MPa. After the compressor 10, the synthesis gas is fed into the heat exchanger 11 where it is heated product stream of the reactor 12 to the reaction temperature for the synthesis of methanol. After the heat exchanger 11 synthesis gas is directed into the reaction zone of the reactor 12 in which the reaction occurs the formation of methanol. At the entrance to the 12 original reactants are heated boiling in the annular space of the coolant. Due to intensive heat exchange between the reaction stream and cooled significant gradients in the reaction zone does not occur. Next, the gaseous product stream through a cooler-condenser 13 is supplied to the separator 14 to the water. Non-condensable reaction products through the heat exchanger 16 is directed into the reactor 17. The operating conditions of the reactors 12 and 17 are identical. In the reactor 17 is received 1612,7 kg/h of methanol. Composition: 98,0 wt.% methanol, 2.0 wt.% water. Non-condensable gases after the separator 19 is fed to the suction side of the compressor 21 in which they comprimida to the pressure of 6.0 MPa. While the volumetric rate of the components of synthesis gas: methane - 2120 nm3/h, carbon dioxide - 1467,3 nm3/h, carbon oxide - 2146,56 nm3/h, the hydrogen - 11751,5 nm3/h, nitrogen - 107,1 nm3/H. After the heat exchanger 22, the synthesis gas is sent into the reactor 23, in the entrance area which it is heated to the reaction temperature. Then the synthesis gas enters the primary zone of the reactor 23. It is the conversion of synthesis gas to methanol. 23 is formed 3003,7 kg/h of methanol. Composition: methanol is 97.9 wt.%, water of 2.1 wt.%. Next, the gas stream passes through a cooler-condenser 24 to the separator 25, which is the condensation of methanol. Non-condensable gases (volume velocity components of synthesis gas: methane - 2120 nm3/h, the hydrogen - 9803,6 nm3/h, carbon dioxide 1247,2 nm3/h, carbon oxide - 1502,6 nm3/h, nitrogen - 107,1 nm3/h) is sent to the heat exchanger 27 and then in whre 28 produced 1411,6 kg/h of methanol. Its composition: a 87.0 wt.% methanol, 13,0 wt. % of water. From the separators 14, 19, 25, 30 the collected methanol in the amount of 8704,45 kg/h goes into the General collection. The composition of the obtained methanol: 96,55 wt.% methanol, of 3.45 wt.% water.

Claims

1. A method of producing methanol, comprising the stage of desulfurization of hydrocarbon gas, the stage of synthesis gas from hydrocarbon gas in the reforming reactor, the stage of compression of the synthesis gas, the stage catalytic conversion of synthesis gas into methanol in a reactor, consisting of several catalytic reactors, including heating operation and the conversion of synthesis gas to methanol in each reactor, the operation of cooling the reaction products and separating methanol after each reactor, the operation disposed of "tail gas", characterized in that in the first two traffic flow reactors reactor system, the process of methanol synthesis is carried out in the pressure range of 3.0-4.5 MPa, temperature 160-320oWith volumetric flow rates of 500-1000 h-1and the last two on traffic flow reactors reactor system, the process of methanol synthesis is carried out in the pressure range 5.0 to 8.0 MPa, temperature of 160-300oWith volumetric flow rates 1000-10000 h-1

3. The method according to p. 1 or 2, characterized in that the steam generated in the reactor for methanol synthesis and steam generated "smoke" gas reforming reactor is sent to a steam turbine to generate electricity.

4. The method according to any of paragraphs.1-3, characterized in that a part of the produced methanol is used as absorbent absorption-desorption of complex plants for the concentration of carbon dioxide in the portion of the stream of tail gases directed into the reactor reforming hydrocarbon gas.

5. The method according to p. 1, characterized in that the aqueous distillation residues of distillation columns, the concentration of methanol served in the catalytic reactor water purification from methanol and purified water is sent after additional training in the reactor reforming hydrocarbon gas.

 

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FIELD: hydrocarbon conversion catalysts.

SUBSTANCE: catalyst for generation of synthesis gas via catalytic conversion of hydrocarbons is a complex composite composed of ceramic matrix and, dispersed throughout the matrix, coarse particles of a material and their aggregates in amounts from 0.5 to 70% by weight. Catalyst comprises system of parallel and/or crossing channels. Dispersed material is selected from rare-earth and transition metal oxides, and mixtures thereof, metals and alloys thereof, period 4 metal carbides, and mixtures thereof, which differ from the matrix in what concerns both composition and structure. Preparation procedure comprises providing homogenous mass containing caking-able ceramic matrix material and material to be dispersed, appropriately shaping the mass, and heat treatment. Material to be dispersed are powders containing metallic aluminum. Homogenous mass is used for impregnation of fibrous and/or woven materials forming on caking system of parallel and/or perpendicularly crossing channels. Before heat treatment, shaped mass is preliminarily treated under hydrothermal conditions.

EFFECT: increased resistance of catalyst to thermal impacts with sufficiently high specific surface and activity retained.

4 cl, 1 tbl, 8 ex

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