A method of producing methanol

 

(57) Abstract:

The invention relates to the field of energy-saving and resource-saving chemical processes and, in particular, to energy-efficient methods of producing methanol from natural gas and "tail" hydrocarbon gases of industrial plants. A method of producing methanol from gaseous hydrocarbons includes a step of partial oxidation of hydrocarbons, the stage of purification of the synthesis gas, the stage of conversion of synthesis gas to methanol in a number of interconnected reactors, the extraction of the methanol, stage heat recovery tail gas in the energy and/or thermal devices. The process of partial oxidation of gaseous hydrocarbons is carried out in energomehanicheskom unit consisting of a power machine and the catalytic reactor at a molar ratio of oxygen to gaseous hydrocarbons less than 0.6, the molar ratio of water vapor to the gaseous hydrocarbons less than 0.7 and the temperature in the reaction zone of the catalytic reactors over 700oWith, and the process of methanol synthesis from synthesis gas with a content of nitrogen than about 30. % of spend under cyclic changes in the concentration of raw material in the input streams of the standards for raw materials and energy, to obtain high purity methanol. 7 C.p. f-crystals, 2 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, gas processing and metallurgical industries.

The invention in particular relates to a method for production of methanol from a hydrocarbon gas via synthesis gas from partial oxidation with air, oxygen-enriched air, the flow of oxygen-containing gas with a high content of nitrogen with subsequent conversion of the resulting synthesis gas to methanol.

The traditional technology of production of methanol from natural gas are characterized by significant capital and energy costs. Usually the first stage in the process of production of methanol from natural gas is the stage of synthesis gas production. It is in the steam reforming of gaseous hydrocarbons. However, not achieved their full transformation into synthesis gas and therefore the residual hydrocarbons are converted in the future in the steam-oxygen conversion. It's IP is energy costs. Additionally, there is a steam conversion of carbon monoxide to increase the content of hydrogen in the synthesis gas and the additional allocation of the resulting carbon dioxide from synthesis gas. The cost obtained by the traditional methods of synthesis gas containing a small amount of nitrogen is high enough that the produced synthesis gas can be used, in addition to the production of methanol in the production of olefin production and motor fuels. This circumstance is due to the fact that the steam reforming reaction of methane and gaseous hydrocarbons vysokoekonomichny and she, along with steam-oxygen conversion of gaseous hydrocarbons is carried out in expensive equipment at considerable capital cost.

In the traditional industrial technologies for production of methanol synthesis gas is converted to methanol in a catalytic reactor at low degrees of conversion of the feedstock, usually no more than 5-7%. So neprevyshenie raw material is fed to the recirculation, which brings additional costs to the economy of these industries.

Known technologies for the production of synthesis gas from natural gas (see Patent US 5177114), Sebastopolis. This is achieved primarily due to the fact that the synthesis gas obtained by partial oxidation of natural gas. Moreover, as the oxidant used is not oxygen, air enriched with oxygen. Cost reduction is achieved by:

1. Reduce the cost of producing oxygen-enriched air in comparison with the costly production of oxygen.

2. The use of simpler and less expensive equipment.

3. Reduce operating costs.

The disadvantages of this process should include the need for the production of synthesis gas containing significant amounts of nitrogen (up to about 40. %). Therefore, the production of methanol must BasicInstallation scheme, otherwise the cost of the target product again would be increased due to the recirculation of large flows of inert components such as nitrogen and methane. Thus, the shortcomings of the existing schemes processing of natural gas lie in the complexity of the technological design process, the use of a large number of units of technological equipment, as well as the lack of flexibility of technological schemes for raw materials.

The main disadvantage of the invention, taken as a prototype, is that the process of methanol synthesis on the basis of a synthesis gas containing significant amounts of nitrogen, is carried out in reactors with low performance on the target product. This fact leads to the necessity of using reactors with a large reaction volume, which leads to an increase of metal reactor site and increase the amount of used catalyst. The latter, in turn, increases the cost price of produced methanol.

In the present invention are the following tasks: create energozatratnogo process for the synthesis of methanol from natural gas with low expenditure norms for raw materials and energy, with increased operating life of the catalytic apparatchik to obtain high purity methanol.

These tasks are solved in the method of producing methanol, comprising a stage of partial oxidation of hydrocarbons, the stage of purification of the synthesis gas, the stage of conversion of synthesis gas to methanol in the number of series-connected reactors, the extraction of the methanol, stage heat recovery tail gas in the energy and/or thermal devices.

The process of partial oxidation of gaseous hydrocarbons occurs in energomehanicheskom unit consisting of a power machine and the catalytic reactor at a molar ratio of oxygen to gaseous hydrocarbons less than 0.6 and the molar ratio of water vapor to the gaseous hydrocarbons of less than 0.7 at a temperature in the reaction zone of the catalytic reactors over 700oC. the synthesis of methanol from synthesis gas with a content of nitrogen than about 30. % of spend in the number of interconnected reactors under cyclic changes in the concentration of raw material in the input streams each of them.

In the working volume of the energy of the machine serves the initiators of the partial oxidation of gaseous hydrocarbons.

In the working volume of the energy of the machine serves the products of partial oxidation of hydrocarbons in the katal is not, and/or carbon dioxide.

In the reaction volume of the catalytic reactor feed steam, superheated exhaust gases of thermal devices.

Gaseous hydrocarbons for the process of partial oxidation of fuel due to the heat tail gas catalytic reactors and/or energy and/or thermal devices.

Phase methanol synthesis in catalytic reactors are in the catalytic reactor at a volumetric flow rates 500-10000 h-1the temperature in the reaction zone 160-300oC, a pressure of 0.4-10.0 MPa.

The synthesis gas is fed to the catalytic reactor for methanol synthesis when the content of nitrogen than about 30. % when the molar ratio of hydrogen to carbon monoxide in the range from 2.8:1 to 1.4:1.

The synthesis gas is divided into two streams, one of which enrich the hydrogen separation membrane element type and fed to the first catalytic reactor, adjust the molar ratio of hydrogen to carbon monoxide, and the second stream depleted in hydrogen, is mixed with the gas stream leaving the catalytic reactor for methanol synthesis, and direct energy and/or thermal devices for the production of electricity and/or steam generation vis use of the installation for production of methanol, consisting of energometallurgicheskogo unit for production of synthesis gas by partial oxidation of gaseous hydrocarbons in the energy machine 1 and the partial catalytic oxidation of gaseous hydrocarbons in the catalytic reactor 2, the catalytic unit of methanol synthesis, consisting of three catalytic reactors 5, 6, 7 and heat recovery unit tail gas.

Weekend zone catalytic reactors 5, 6, 7 are connected refrigerators-capacitors 11, 14, 17 and separators 12, 15, 18. At the entrance to the catalytic site of methanol synthesis posted by the compressor 3, and at the entrance to the catalytic reactor 5, 6, 7 - exchangers 8, 13, 16.

In Fig. 2 schematically shows energy-chemical plant for methanol in accordance p. 8. of the claims. The installation further comprises a membrane apparatus 19, the gas turbine 20, furnace-heated steam and gas flow 21, the steam turbine 22.

An energy-chemical method of producing methanol is implemented with the system shown in Fig. 1, 2, as follows.

The feedstock is purified from sulfur compounds in natural gas is mixed with a given quantity of air or with a pre-oxygen enriched air. Prov.in and after further dilution with steam is fed into the energy machine, which occurs along with the formation of synthesis gas and power generation. The second part of the flow of the gas mixture is mixed with superheated exhaust gases energy and heat engines steam generated in the heat exchange elements of the catalytic reactor 5, 6, 7. The synthesis gas obtained in the energy machine 1 and the catalytic reactor 2, is mixed and fed to the compressor 3, in which its pressure is increased to the worker, in particular to 4.0-10.0 MPa.

Synthesis gas with a given hydrogen content with a bulk velocity 500-10000 h-1is sent to the oxygen reactor 4, in which it is freed from excess oxygen. He then enters the heat exchanger 8, which heats the product flow reactor 5 to a temperature close to the temperature of the beginning of the reaction, the production of methanol. After the heat exchanger 8 synthesis gas enters through an inlet zone 9 of the reactor 5 in area main conversion of synthesis gas 10 in which is formed the main quantity of the product methanol. From the reactor 5, the gas stream passes the heat exchanger 8, where it heats the feedstock to a temperature close to the temperature in the reactor 5. He then through a cooler-condenser 11 enters the 13 are in the input area 9 of the reactor 6.

The operating conditions of reactors 6 and 7 is similar to the operating conditions of the reactor 5. From the reactor 7 product gas stream is fed through a cooler-condenser 17 in the separator 18, where it is condensed to liquid products of the reaction of methanol synthesis, and non-condensable gases are fed into the recovery unit tail gas (shown in Fig. 2.). External communication reactors 5, 6, 7 are arranged so that the source of synthesis gas may flow initially in each of the reactors 5, 6, 7, and then any combination of the following.

Variant of the method corresponding to p. 8 claims, as follows.

Komprimierung synthesis gas is then divided into two streams, one of which enters membrane element 19, providing for the enrichment of the synthesis gas with hydrogen. Permeate stream enriched in hydrogen, is fed into the suction line of the compressor first stage, recently stream depleted in hydrogen, mixed with the "tail" gases of the reactor site for methanol synthesis.

Komprimierung in compressor 3-enriched raw hydrogen stream passes through three series-connected reactor to form methanol in each of them (the same flow membrane element 19 and is directed to the gas turbine 20 as a gas fuel to generate electricity. The exhaust gases of the turbine 20 are received in the furnace 21 for heating the steam coming from the reactor 5,6,7. One stream of superheated steam from 21 enters the steam turbine 22 to generate electricity. Another stream of superheated steam from 21 enters Energeticheskiy block 1,2 for the production of synthesis gas with a high ratio of hydrogen to carbon monoxide.

The above examples do not exhaust all possible implementation of the method of producing methanol.

Therefore, the physico-chemical meaning of the present invention is that in the first stage of production of methanol production of synthesis gas is carried out in parallel units of homogeneous and heterogeneous synthesis gas production. This process occurs at the fixed molar ratio of oxygen : hydrocarbon raw materials, allowing to suppress side reactions and, therefore, reduce the consumption of raw materials per unit of finished product. In the second stage of the process of obtaining the actual methanol is made from synthesis gas with a nitrogen content of more than about 30. % in three connected with each other catalytic reactors. Transport and communication of these reactors arranged in such a way that the original interanimate operation of oxidation-reduction in the catalytic layers so that that drop their activity slowed down, and the service life of the catalysts is increased in comparison with the catalysts employed according to the traditional schemes of their operation.

The invention is illustrated below by examples of embodiments of the method.

Example 1. The air of 3453,09 m3/h is fed to the membrane element enrichment of air. Permeate flow 778,67 m3/h with oxygen content of about 31. % mixed with 338,05 m3/h of natural gas (methane content in it 98,8 about. %). Recently flow 2674,42 m3/h is discharged into the atmosphere. The total mixed flow of natural gas and oxygen-enriched air - 1165,203/H. He, after mixing with 100 m3/h of superheated steam is divided into two streams - 80% of the flow (volume) energy enters the car, 20% of the flow (by volume) in the catalytic reactor. Received in energomehanicheskom unit, the synthesis gas has the following composition: molar flow of carbon monoxide - 15,18 KMOL/h of hydrogen - 29,47 KMOL/h of carbon dioxide - 2,08 KMOL/h of oxygen of 0.4 KMOL/h of methane - 0,07 KMOL/h, nitrogen - 22,60 KMOL/h

The flow of synthesis gas goes to the compressor 3 and the membrane element enrichment synthesis gas hydrogen 19, the Total volume sarada, equal 1486,3 m3/H. the composition of the stream after reactor 4: carbon monoxide - 14,11 KMOL/h, the hydrogen of 28.96 KMOL/h, carbon dioxide - 1,98 KMOL/h, methane - 0,064 KMOL/h, the oxygen - 0,0 mol/h, nitrogen - 21,24 KMOL/hour, a Pressure in the flow of synthesis gas to 6.0 MPa, the temperature of the flow - 363 K. Next, the flow of the synthesis gas passes through the heat exchanger 8, where it is heated product flow reactor 5 to a temperature close to the temperature of the synthesis reaction of methanol, and into the reactor 5. In the entrance area 9 the stream of synthesis gas is heated to the temperature of the beginning of methanol synthesis and the primary catalytic zone 10 is the synthesis of methanol. The total molar flow at the outlet of the reactor 5 - 51,5 KMOL/h Threads: carbon monoxide - 6.73 x KMOL/h of hydrogen - 14,05 KMOL/h of carbon dioxide is 2.01 KMOL/h of methanol - 7,30 KMOL/h water - 0.11 KMOL/h the Reaction mixture at the outlet of 5 is cooled in the cooler-condenser 11 and the separator 12 from the non-condensable gas components separated vodnoetanolnyh product.

Noncondensable gas product is heated product gases from reactor 6 in the heat exchanger 13 and is fed into the reactor 6. The operating conditions of the reactor 6: P=5,91 MPa, T=480 K. the Composition of the output product flow: carbon monoxide - 4.00 KMOL/h, the Torah 6 enters the cooler-condenser 14 and the separator 15, which is separated from the gas stream with water-methanol product.

Noncondensable gas product of the reactor 6 is heated in the heat exchanger 16 grocery flow reactor 7 and enters the reactor 7. The operating conditions of the reactor 7: pressure, 5,91 MPa, temperature 478 K. the composition of the reactants at the reactor exit 7: carbon monoxide - 2,96 KMOL/h of hydrogen - 6,51 KMOL/h, carbon dioxide is 2.01 KMOL/h, methanol-raw - 1,025 KMOL/h water - 0.015 KMOL/h

Condensed in the separator 12, 15, 18 methanol is displayed in the total capacity. The total number of water-methanol product - 11,18 KMOL/H. it contains 98.5% of the molar methanol and 1.5% molar of water. Recently stream from the membrane element 19 is mixed with a stream of non-condensable gases from the reactor 7. The composition of the stream entering the gas turbine 20: carbon monoxide - 4.02 KMOL/h of hydrogen - 7,02 KMOL/h, carbon dioxide - 2,11 KMOL/h, methane - 0,07 KMOL/h, nitrogen, and 22.6 KMOL/h Power turbine produced by using the above gas - 270 kW.

The exhaust gases of the turbine are received into the furnace 21, which serves 270 kg/h of steam medium pressure generated in the catalytic reactors 5, 6, 7. One part of the received peregrinate.

The total gas conversion to methanol on carbon 69,46%. The total number of produced methanol - 352,48 kg of 388,05 m3natural gas

Example 2. In the mixer serves 970 m3/h of natural gas, which is mixed with air and steam with the formation of the mixture, which corresponds to a molar ratio of water vapor to hydrocarbon, equal to 0.60, and the molar ratio of oxygen to hydrocarbons is equal to 0.65. Formed by the mixture of natural gas, water vapor and air is delivered, bypassing the power unit 1, immediately to the catalytic reactor 2, which is formed 5350 m3/h of synthesis gas composition: hydrogen - 37,8 about. per cent, of oxide of carbon - 18,6 about. %, carbon dioxide - 2,8 about. %, methane - 0,8 about. %.

The resulting synthesis gas (total molar flow - 238,84 KMOL/h) is fed into the compressor (membrane element is not used) and then to the catalytic reactor 4, where there is a complete clean synthesis gas from oxygen. The purified synthesis gas enters the heat exchanger 8 where it is heated product gases from reactor 5 to a temperature close to the temperature of the beginning of methanol synthesis. Next, the synthesis gas is sent into the reactor 5, in the input area 9 which it is heated to the temperature of the beginning of reakcija, temperature 208oC. the Molar flow at the outlet of the reactor 6, the following: hydrogen - 41.5 KMOL/h, carbon oxide - 20,6 KMOL/h, carbon dioxide - 6,9 KMOL/h, methanol-raw - 24,3 KMOL/h

From the reactor 5 product gas stream enters the heat exchanger 8 for heating the raw material stream entering the reactor 5. Next product stream 5 passes the cooler-condenser 11 and enters the separator 12, in which methanol is separated from non-condensable reaction products. They are heat exchanger 13 and the reactor 6. The composition of the non-condensable components of the product gas at the outlet 6 of the following: hydrogen - 19,6 KMOL/h, carbon oxide - 8,7 KMOL/h, carbon dioxide - 6,6 KMOL/h of the Rest is nitrogen, methane.

After cooling the product gas in the refrigerator condenser 14, and selection separator 15 non-condensing methanol reactants are directed through the heat exchanger 16 into the reactor 7. The molar flow at exit 7: hydrogen - 10,2 KMOL/h, carbon oxide - 4,8 KMOL/h, carbon dioxide - 5.0 KMOL/h, methanol-raw - 5.3 KMOL/h the Rest inert.

Non-condensable gases from 7 sent to the gas turbine to generate electricity and steam produced in catalytic reactors, in absee the number of produced methanol 1350 kg/h, mass content of water in the liquid reaction products of 3.2 wt. %.

Organization cyclic switching of feeding a feedstock in the catalytic reactor according to the scheme of the first - second - third reactor (1-->2-->3), second - third - first (2-->3-->1), the third first second (3-->1-->2), the first - second - third reactor (1-->2-->3) after every 600 hours of operation of each scheme can reduce the rate of decrease of the activity of the catalyst by 15-17%.

1. A method of producing methanol from a gaseous hydrocarbon, comprising a stage of partial oxidation of hydrocarbons, the stage of purification of the synthesis gas, the stage of conversion of synthesis gas to methanol in a number of interconnected reactors, the extraction of the methanol, stage heat recovery tail gas in the energy and/or thermal devices, characterized in that the process of partial oxidation of gaseous hydrocarbons is carried out in energomehanicheskom unit consisting of a power machine and the catalytic reactor at a molar ratio of oxygen to gaseous hydrocarbons less than 0.6, the molar ratio of water vapor to the gaseous hydrocarbons less than 0.7 and the temperature in the reaction zone of the catalytic reactors over 700o< the change in the concentration of raw material in the input streams each of them.

2. The method according to p. 1, characterized in that the working volume of the energy of the machine serves the initiators of the partial oxidation of gaseous hydrocarbons.

3. The method according to p. 1, characterized in that the working volume of the energy of the machine serves the products of partial oxidation of gaseous hydrocarbons in the reactor and/or products of partial oxidation of gaseous hydrocarbons in the energy machine and/or carbon dioxide.

4. The method according to p. 1, characterized in that the reaction volume of the catalytic reactor feed steam, superheated exhaust gases of thermal devices.

5. The method according to p. 1, characterized in that the gaseous hydrocarbons to the process of partial oxidation of fuel due to the heat tail gas catalytic reactors and/or energy and/or thermal devices.

6. The method according to p. 1, characterized in that the stage of synthesis of methanol are in the catalytic reactor at a volumetric flow rates 500-10000 h-1the temperature in the reaction zone 160-300oWith the pressure of 4.0-10.0 MPa.

7. The method according to p. 1, characterized in that the synthesis gas is fed to the catalytic methanol synthesis reactor at a molar ratio of hydrogen to the oxide perodua thread one of which enrich the hydrogen separation membrane element type and fed to the first catalytic reactor, adjust the molar ratio of hydrogen to carbon monoxide, and the second stream depleted in hydrogen, is mixed with the gas stream leaving the catalytic methanol synthesis reactor and sent to the energy and/or thermal devices for the production of electricity and/or produce high-pressure steam.

 

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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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