A method of producing methanol

 

(57) Abstract:

The invention relates to a method for producing methanol. A method of producing methanol includes a step of generating synthesis gas from gaseous hydrocarbons, 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 in each reactor, the operation of cooling the reaction products and the allocation of produced methanol after each reactor, the operation of recycling tail gas. The hydrogen obtained after steam reforming part made of methanol, mixed with the synthesis gas from the formation of the prepared synthesis gas with a molar ratio of hydrogen to carbon monoxide in the range of 1.4:1 and 3:1 and it is served in a reactor system for the catalytic conversion of synthesis gas to methanol. The invention improves the efficiency of the process. 6 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 IU the and from synthesis gas, obtained in catalytic carbon dioxide-steam-oxygen or steam-oxygen processes the conversion of hydrocarbon gases, as well as in homogeneous processes of partial oxidation of natural gas with air or air enriched with oxygen.

In industrial production the production of methanol, the methanol synthesis is usually carried out in two stages:

1. At the first stage in the two types of reactors is the synthesis of the synthesis gas. In a tubular furnace is implemented vysokoenergeticheskaya the reaction of steam reforming of gaseous hydrocarbons and mining reactor steam-oxygen conversion of unreacted in the first stage gaseous hydrocarbons. Developed processes involving the combination of these stages.

2. In the second stage is the actual conversion of synthesis gas to methanol. In order to maintain high performance catalytic reactors and to provide sufficient purity of the produced methanol in industrial apparatuses is implemented by the flow regime of the gas stream, close to the turbulent, low conversion of the feedstock that does not exceed 5-7%, in some cases up to 15%. Unreacted synthesis gas, after separation IU is such industrial technologies the following:

1. High capital costs.

2. The low degree of use of the reaction volume of industrial machines.

3. The use of expensive equipment.

4. The complexity of the control systems.

5. Substantial consumption norms of raw materials.

6. Significant energy consumption.

In view of this, the cost of the produced methanol is quite high and it cannot be used as raw materials for the profitable industries of receipt of monomers (ethylene, propylene) or motor fuels.

Known industrial technology for the production of synthesis gas with high temperature conversion of hydrocarbon gases, including the incomplete combustion of hydrocarbons in oxygen or steam-oxygen mixtures in homogeneous reactors in the absence of catalyst. The main products of these reactions are hydrogen, carbon dioxide, carbon monoxide, water. The possibility of conducting the process in the absence of catalyst is provided by the high temperature combustion of hydrocarbons. The main advantages of the process of high-temperature conversions - easy technological schemes and low capital expenditures.

However, this process has the Aulnay ratio of hydrogen to carbon monoxide in the synthesis gas.

3. High consumption rates of the raw materials.

4. Significant content stubborn fine carbon in the synthesis gas.

The above disadvantages of the process of high-temperature conversion of hydrocarbons does not allow to significantly reduce the cost of produced synthesis gas and, consequently, the cost of methanol.

Known techniques for producing methanol from natural gas (US 5245110), which provide for the production of synthesis gas by partial oxidation of natural gas with air and oxygen-enriched air. Reducing the cost of synthesis gas is achieved by:

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. The reduction in capital and operating costs.

In the second stage production of methanol synthesis gas with a high content of nitrogen converted into methanol in four or six series-connected reactors with intermediate output generated in reactors of methanol after each reactor. At the outlet of the reactor building naray hydrogen, mixed with the synthesis gas and enters the reactor block, and recently stream is sent to a gas turbine to generate electricity. The nitrogen in the system catalytic reactor recycle only partially with permeate thread, most of it is discharged into the atmosphere together with the exhaust gases of the gas turbine.

Closest to the claimed method of producing methanol, selected as a prototype, a method described in the patent (RU 2152378). In the method prototype convert synthesis gas with a high content of nitrogen in the three serially connected catalytic reactors with intermediate separation of forming methanol after each catalytic reactor. The purposeful organization of thermal regimes of the work of the reactors is provided by the preset conversion of synthesis gas at high quality target product.

The disadvantages of the known methods of production of methanol on the basis of the synthesis gas with a significant nitrogen content (>40%) are:

1. The low productivity of the catalytic reactors.

2. Significant deactivation of the catalysts.

3. The complexity of the management process when changing the image quality the e processes at the organization of small and medium enterprises as on gas fields, and gas petrochemical and chemical plants.

In the present invention are the following tasks: achieving high performance in the production of methanol from natural gas, the reliability of industrial plants with the composition of the raw materials, increase the duration of use of catalysts, obtaining produced methanol of high quality, creating energosensory industrial plants for methanol synthesis.

These tasks are solved in the method of producing methanol, comprising a step for synthesis gas from gaseous hydrocarbons, 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 in each reactor, the operation of cooling the reaction products and the allocation of produced methanol after each reactor, the operation disposed of "tail gas". When this hydrogen is obtained after steam reforming part made of methanol, mixed with the synthesis gas from the formation of the prepared synthesis gas with a molar ratio of hydrogen to carbon monoxide in Litichevsky conversion of synthesis of methanol is carried out in the temperature range 160-320oC, pressure of 4.0-10.0 MPa, volumetric flow rates 500-5000 h-1.

Obtaining synthesis gas is carried out at a molar ratio of oxygen:gaseous hydrocarbons less than 0.7.

Hydrogen production steam conversion of methanol is carried out in the temperature range 120-320oC, pressures of 0.1-10.0 MPa, volumetric flow rates 200-10000 h-1.

The oxygen content in the synthesis gas entering the catalytic reactor for methanol, is to 1.0 vol.%.

The prepared synthesis gas is fed sequentially, periodically in each of the reactors in the reactor for methanol synthesis when continuously operating the other.

The synthesis gas is divided into two streams, one of which is enriched with hydrogen mass transfer in the membrane installation type and serves at the reactor site for methanol synthesis, and the second stream depleted in hydrogen, is mixed with a stream of gas leaving the last catalytic methanol synthesis reactor, and gaseous hydrocarbons and the mixture is sent to the energy and/or heating installation as a gas fuel.

In Fig.1 illustrates the essence of the method of the invention, which proposes the use of promyshlennogo raw materials, in particular, natural gas, unit of compression of the synthesis gas 2, reactor cleaning synthesis gas 3 from the oxygen reactor preparation of synthesis gas 4 steam reforming of methanol, reactors 5, 6, 7 of methanol synthesis on the basis of the synthesis gas, heat exchangers 8, 13, 16, in which preheating the syngas coolers-capacitors 11, 14, 17 the reaction products of the production of methanol, separators 12, 15, 18, in which the separation of condensable and non-condensable reaction products of the production of methanol, capacity 19 product methanol.

A method of producing methanol from gaseous hydrocarbons is implemented with the system shown in Fig.1, as follows.

The source of gaseous hydrocarbons, particularly natural gas, is mixed with the oxidant is air or oxygen-enriched air and sent to the reactor block partial oxidation of gaseous hydrocarbons. It energy chemical machines (internal combustion engines, gas turbines, homogeneous chemical reactors) or/and in the catalytic reactor is in the process of obtaining synthesis gas. Next, the synthesis gas is delivered to the Department of compression, where he compremise the form of further oxidation of gaseous hydrocarbons, usually contains 0,1-0,8% vol. the oxygen. The latter has a concentration greater than its allowable steady state concentration in the input streams of synthesis gas reactor for methanol synthesis. The lower stationary oxygen concentration to values 0,01-0,001% is achieved in the reactor 3, in which the oxidation by the oxygen of carbon monoxide to carbon dioxide. Next, the synthesis gas with a given concentration of residual oxygen is mixed with hydrogen-rich recycle gas from the reactor 4 steam reforming of methanol, and fed into the heat exchanger 8, where it is heated product flow reactor 5 to the temperature close to the temperature at which the reaction of methanol synthesis. After the heat exchanger 8, the synthesis gas is sent into the reactor 5, in the input area 9 which it is heated to the reaction temperature. Then the synthesis gas is delivered to the zone 10, which is the main conversion of synthesis gas to methanol. In the area of 9 original reactants are heated in boiling shirt reactor 5 by the carrier, and in the zone 10, the heating of the reaction mixture is carried out as a result of exothermic chemical reactions. From the reactor 5 product stream passes through the heat exchanger 8, where it heats the feedstock to a temperature close to t the torus 12, where is the condensation of methanol. Non-condensable gases are directed into the heat exchanger 13 and then in the input zone of the reactor 6.

The conditions of operation of the reactors 6, 7 are 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 the condensation of methanol, and non-condensable gases are fed into the recovery unit tail gas (shown in Fig. 2). Produce methanol from collections 12, 15, 18 is directed into the tank 19, from which a single stream is sent to a purification unit of methanol and then to the consumer, and the other stream is directed into the reactor 4 steam reforming of methanol. The steam in the reactor 4 is supplied from the steam drum, the heat transfer systems of reactors 5, 6, 7. Obtained in the reactor 4 steam reforming of methanol hydrogen is mixed with the input streams of synthesis gas reactors 5, 6, 7. Gas transport communications installation is organized so that periodically the synthesis gas with a high concentration of hydrogen may be fed into each of the reactors 5,6,7.

Option ways, corresponding to p. 7, is as follows (Fig.2).

Raw materials - natural gas mixture the aqueous oxidation of gaseous hydrocarbons. It turns out the synthesis gas. Next, the synthesis gas is fed into the compressor 2, the suction line of the first stage which comes permeate stream from the membrane unit 20. In membrane apparatus 20 receives a smaller portion of the flow of synthesis gas after the compressor 2. 20 the total gas flow is divided into two streams. First - permeate stream enriched in hydrogen, the second - recently stream depleted of hydrogen and enriched with nitrogen.

Enriched with raw hydrogen stream, kompremirovannyj in the compressor 2 is supplied to the reactor 3 purification from oxygen and after mixing with a stream of hydrogen flowing from the reactor 4, is sent to the reactor site of synthesis of methanol containing reactors 5, 6, 7. The methanol produced in 5, 6, 7, after cooling in refrigerators-capacitors 11, 14, 17 is separated in the separators 12, 15, 18 from the non-condensable gases collected in the total capacity of 19 and after distillation purification is displayed with the installation. Part of the flow of the methanol fed into the reactor 4, which result from the reaction of steam reforming of methanol is produced hydrogen. Non-condensable stream of synthesis gas after the separator 18 is combined with retenti flow membrane device 20 and sent to the gas turbine astrobingo space reactors 5, 6, 7. Superheated steam enters the steam turbine 23 to generate electricity.

The above examples do not exhaust all possible options for implementing a method of producing methanol.

Therefore, the physico-chemical meaning of the present invention is that the synthesis of methanol in a nitrogen atmosphere, the synthesis gas with adjustable ratio of hydrogen to carbon monoxide, which allows to achieve high productivity process for long term use of catalytic systems. Thus the reaction rate of methanol synthesis depends to a large extent on the content of hydrogen in the raw materials than on the content of carbon monoxide in it. Therefore, partial removal of carbon from the system by the reaction of steam reforming of methanol is covered with an excess of greater depth conversion of carbon monoxide and carbon dioxide to methanol by increasing the concentration of hydrogen in the synthesis gas. When carrying out the reaction of steam reforming of methanol using the steam generated in the heat exchange system of catalytic reactors for methanol synthesis. Characteristics of steam close to the conditions of the reaction of steam reforming of methanol. Therefore, additional energy snige specific examples of embodiments of the method.

Example 1. (prototype). In the energy machine (gas turbine, internal combustion engine) is 1002 m3/h of natural gas and the oxidant (air). Formed 4608 m3/h of synthesis gas composition: hydrogen - 30,05% vol., carbon monoxide - 17,41% vol., carbon dioxide - 2,03% vol., inert components of 50.4%. For every 1000 m3clean synthesis gas (without inert components) produced more than 0.3 MW of electricity. The resulting synthesis gas compremised 2 and cleaned if necessary from oxygen 3, is fed to the catalytic reactor 5, in which at a pressure of 6.5 MPa and a temperature of 200oIs methanol in the amount of 435,4 kg/hour, the Reaction mixture is from 5 is cooled in the heat exchanger 8, the cooler-condenser 11 and the separator 12, the methanol is separated from the synthesis gas. Neskondensirovannyh gas stream is heated to the reaction products from 6 to 13 and enters the reactor 6, in which at a pressure of 6.4 MPa and a temperature of 210oIs methanol in the amount of 127,8 kg/h composition of the reactants at the entrance to the 6 following: hydrogen - 20,5%, carbon monoxide - 13,15 about.%, carbon dioxide - 2,47%, vapour-gas mixture of the reaction products of the reactor 6 is cooled in heat exchanger 13, the refrigerator condenser 14, and the methanol OTDELA is gerada - of 11.61%, carbon dioxide - 2,66% vol. after heating in the heat exchanger 16 are received in the catalytic reactor 7, in which at a pressure of 6.3 MPa and a temperature of 210oIt 35,84 kg/h of methanol. Total amount of produced methanol - 599,04 kg/h composition of the obtained product methanol: water (2.5 wt.%, methanol - 97.5 wt.%, organic impurities in trace amounts. "Tail gases are directed into the gas turbine to generate electricity.

Example 2. In the energy machine (gas turbine, internal combustion engine) and the catalytic reactor is fed 1002 m3/h of natural gas and the oxidant (air). Formed 4608 m3/h of synthesis gas composition: hydrogen - 30,05% vol., carbon monoxide - 17,41% vol., carbon dioxide - 2,03% vol., inert components and 50.4% vol. For every 1000 m3clean synthesis gas (without inert components) produced more than 0.3 MW of electricity. The synthesis gas in the presence of small amounts of oxygen is directed into the reactor 3 for carrying out the process of selective oxidation of carbon monoxide to carbon dioxide. The part produced in reactors 5, 6, 7 methanol in the amount of 104,96 kg/h is subjected to the reaction of steam reforming of methanol in the reactor 4 and the resulting hydrogen is served in led carbon - 1,9 about. % is sent to the catalytic reactor 5, in which at a pressure of 6.5 MPa and a temperature of 200oIs methanol in the amount of 515,6 kg/hour. The reaction mixture from the reactor 5 is cooled in the heat exchanger 8, the cooler-condenser 11 and the separator 12, the methanol is separated from the synthesis gas. Non-condensable gas stream is heated in 13 products of the reaction of 6 and enters the reactor 6, in which at a pressure of 6.4 MPa and a temperature of 210oIs methanol in the amount of 176,5 kg/h composition of the reactants at the inlet to the reactor 6, the following: hydrogen and 23.1%, carbon monoxide - 11,51% vol., carbon dioxide is 2.44 about. % Vapour-gas mixture of the reaction products of the reactor 6 is cooled in heat exchanger 13, the refrigerator condenser 14, and the methanol is separated from the reaction products in the separator 15. Non-condensable gas component composition: hydrogen - 18,44% vol., carbon monoxide - 9,2%, carbon dioxide - 2,69% vol. after heating in the heat exchanger 16 are received in the catalytic reactor 7, in which at a pressure of 6.3 MPa and a temperature of 210oIt 57,48 kg/h of methanol. The total number produced for the consumer of methanol 644,62 kg/h composition of the obtained product methanol: water is 2.2 wt. % methanol - of 97.8 wt.%, organic impurities in SL>Example 3. In the energy machine (gas turbine, internal combustion engine or the catalytic reactor is fed 1002 m3/h of natural gas and the oxidant (air). Forms 5500 m3/h of synthesis gas composition: hydrogen and 26.8%, carbon monoxide - 14,3%, carbon dioxide - 3,56% vol., methane - 1,29 about. %, nitrogen - 54,05%. Synthesis gas compremised 2 and reactor 3 is cleaned from possible small amounts of oxygen in it. In the mass transfer apparatus 20 is enriched with hydrogen permeate flow and depletion of them retannage flow. The part produced in reactors 5, 6, 7 methanol in the amount of 100 kg/h is subjected to the reaction of steam reforming reactor 4 and the resulting hydrogen is fed into the stream of initial synthesis gas. The prepared synthesis gas composition: hydrogen - 32,44% vol., carbon monoxide - 14,62% vol., carbon dioxide - 3,56% vol., methane is 1.13%, nitrogen - 48,23% vol. sent to the catalytic reactor 5, in which at a pressure of 6.5 MPa and a temperature of 200oIs methanol in the amount of 522,2 kg/h the Reaction mixture from the reactor 5 is cooled in the heat exchanger 8, the cooler-condenser 11 and the separator 12, the methanol is separated from the synthesis gas. Neskondensirovannyh gas stream is heated in 13 products of the reaction of 6 and Postup is/H. Vapour-gas mixture of the reaction products of the reactor 6 is cooled in heat exchanger 13, the refrigerator condenser 14, and the methanol is separated from the reaction products in the separator 15. Non-condensable gas components after heating in the heat exchanger 16 are received in the catalytic reactor 7, in which at a pressure of 6.5 MPa and a temperature of 220oIt 89.1 kg/h of methanol. The total number produced for the consumer product methanol - 853,5 kg/h "Tail gas" reactors 5, 6, 7, combined with retenti flow and the flow of natural gas are directed into the gas turbine 21 to generate electricity. Pairs formed in the annular space of catalytic reactors and additionally heated by the heat of waste gases of the turbine is sent to a steam turbine 23 for additional power generation.

1. A method of producing methanol, comprising a step for synthesis gas from gaseous hydrocarbons, 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 in each reactor, the operation of cooling the reaction products and is the, the hydrogen obtained after steam reforming part made of methanol, mixed with the synthesis gas from the formation of the prepared synthesis gas with a molar ratio of hydrogen and carbon monoxide in the range of 1.4:1 and 3:1 and it is served in a reactor system for the catalytic conversion of synthesis gas to methanol.

2. The method according to p. 1, characterized in that the catalytic conversion of synthesis gas to methanol is carried out in the temperature range 160-320oWith pressure 4,0-10,0 MPa, space velocity 500-5000 h-1.

3. The method according to p. 1, characterized in that the synthesis gas is carried out at a molar ratio of oxygen : gaseous hydrocarbons less than 0.7.

4. The method according to any of paragraphs.1-3, characterized in that the hydrogen production steam conversion of methanol is carried out in the temperature range 120-320oC, pressures of 0.1-10.0 MPa, volumetric flow rates 200-10000 h-1.

5. The method according to any of paragraphs.1-4, characterized in that the oxygen content in the synthesis gas entering the catalytic reactor for methanol, is to 1.0 vol.%.

6. The method according to any of paragraphs.1-5, characterized in that the prepared synthesis gas is fed sequentially, periodically in each of the reactors in reactino, characterized in that the synthesis gas is divided into two streams, one of which is mixed with the hydrogen mass transfer in the membrane installation type and serves at the reactor site for methanol synthesis, and the second stream depleted in hydrogen, is mixed with a stream of gas leaving the last catalytic methanol synthesis reactor, and gaseous hydrocarbons and the mixture is sent to the energy and/or heating installation as a gas fuel.

 

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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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