LU103406B1 - Process and plant for the production of methanol from a carbon-containing feedstock - Google Patents

Abstract

The invention relates to a process for producing methanol from a carbon-containing feedstock. In a process in which efficiency and energy use are optimized, at least the following steps are included: processing of at least one carbon-containing feedstock; gasification in a gasifier and/or pyrolysis in a pyrolysis furnace of the processed carbon-containing feedstock to obtain a crude synthesis gas; processing of the crude synthesis gas to obtain a synthesis gas; methanol synthesis to obtain crude methanol; distillation of the crude methanol to obtain methanol and at least one by-product; extraction of a partial stream from the methanol synthesis and feeding at least a part of the partial stream into the gasifier and/or pyrolysis furnace.

Description

230566 P00LU 09.10.2024

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Description

Process and plant for the production of methanol from a carbonaceous

active ingredient

The invention relates to a process for producing methanol from a carbon-containing feedstock.

In addition, the invention relates to a plant for the production of methanol from a carbon-containing feedstock.

Methanol is produced through an exothermic reaction, which uses as starting materials

The system provides for hydrogen and carbon oxides, which are fed as a gas stream into a suitable reactor for methanol synthesis. These substances can be obtained from various sources.

One possibility is to use a carbon-based energy carrier electricity from a

to subject it to steam reforming or, for example, catalytic partial oxidation, so that a synthesis gas consisting essentially of hydrogen and carbon oxides is obtained. Depending on the type of energy carrier and the method of production of the

Different proportions of hydrogen and the synthesis gas are added.

Carbon oxides – and thus a different stoichiometry – are achieved in the synthesis gas. The resulting stechiometry can then be adjusted by various measures, such as subjecting it to a water-gas shift reaction.

The advantage of this approach is that the energy carrier itself – e.g.

Natural gas can be regularly supplied at high pressure, so that after the synthesis gas has been obtained, only a comparatively small pressure increase is necessary to reach the pressure required for methanol synthesis.

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Another way to provide the starting materials for the synthesis of methanol is to use a gas stream with a high carbon dioxide content and without

to use hydrogen. Such a gas stream can be obtained, for example, from flue gas, i.e., from the exhaust gas of a combustion process. Similarly, such a gas stream could be obtained from a bioethanol production plant. Since such flue gas does not contain hydrogen, this variant requires the...

Hydrogen may be supplied from another source, for example from a

Electrolysis. For methanol synthesis, the gas is regularly circulated with the reactants in a cycle, since a single pass of this gas through the reactor usually does not lead to a sufficiently extensive conversion into methanol.

The converted methanol is regularly removed by condensation from the circulating

Gas is removed. At the same time, however, inert substances also accumulate due to the circulation, which cannot be sufficiently removed by this condensation.

To remove these substances from the cycle, it is necessary to discharge a portion of the circulating gas as purge gas, which can then be burned, for example.

Future-oriented processes or systems utilize an organic

Substance, such as biomass, that is gasified to synthesize methanol. There are various methods for this. Compared to plants for the synthesis of

These plants require methanol produced from fossil fuels.

The process involves more complex pretreatments and also gas purification.

In a typical methanol plant, gasification is carried out using steam and oxygen. The reason for using steam is that the

Biomass is thermally decomposed, and the required water vapor reacts with the carbon from the organic matter to form hydrogen.

Methanol synthesis takes place under high pressure, and when air is used for the synthesis, the nitrogen contained in the air increases the power required, and the nitrogen also reduces the efficiency of the methanol synthesis.

Therefore, the use of oxygen is preferred.

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Conventional plants that have so far operated without biomass are only conditionally competitive in terms of cost as plant systems for the synthesis of methanol specifically from biomass.

The invention is therefore based on the objective of providing a method and a system for

Production of methanol from a carbon-containing feedstock, in particular

To provide biomass where efficiency and energy use are optimized.

This objective is initially achieved in the present invention by the features of the

Claim 1 is solved by the fact that the method at least performs the following functions:

The process includes: processing of at least one carbon-containing feedstock;

Gasification in a gasifier and/or pyrolysis in a pyrolysis furnace of the processed carbon-containing feedstock, to obtain a raw synthesis gas;

Processing of the raw synthesis gas to obtain a synthesis gas;

Methanol synthesis to obtain crude ethanol; distillation of the crude ethanol to

Obtaining methanol and at least one byproduct; removing a

Partial stream of methanol synthesis and supply of at least a part of the partial stream

Into the carburetor and/or pyrolysis oven.

Carbon-containing feedstocks include, in particular, carbon-containing materials.

The term refers to solids and/or carbon-containing liquids. Preferably, the carbon-containing feedstock is biomass. Particularly preferably, the carbon-containing feedstock is waste, for example...

Household waste, plastic, etc.

Accordingly, the processing of the carbon-containing feedstock can be designed in different ways, and it is clear to those skilled in the art that the processing can and must differ for different feedstocks.

Processing can include steps such as drying, torrefaction, carbonization and/or crushing of the carbon-containing feedstock.

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Depending on how the gasification and/or pyrolysis of the processed carbonaceous feedstock takes place, the processing must be adapted accordingly. With a fluidized bed gasifier, it is generally necessary to break down the structure of the carbonaceous material to achieve an acceptable result. With fixed-bed or fluidized bed gasifiers, the processing is usually less complex.

Methanol synthesis takes place in a suitable reactor system. Adiabatic reactors and quasi-isothermal reactors are the most common. In adiabatic reactors

In reactors with a single catalyst bed, the reaction is quenched by adding cold gas at multiple points. The temperature profile along the

The reactor axis is therefore sawtooth-shaped. In reactors where the synthesis gas flows through several axially arranged reactor layers, the

The heat of reaction is removed by an intercooler. In these reactors, the...

Synthesis gas axially, radially or axially/radially through the catalyst beds.

The standard quasi-isothermal reactor consists of a tube reactor cooled by water. The catalyst is located in pipes that serve to remove the

are surrounded by the heat of reaction of water at its boiling point. The temperature of the

The cooling medium is set by a preset pressure in the steam drum.

The synthesis gas flows through the pipes in an axial direction.

The crude methanol leaving the reactor contains water and other impurities.

The quantity and composition of these impurities depend on the

Reaction conditions, the gas used, and the type and lifespan of the

catalyst. The crude methanol contains low-boiling and high-boiling elements.

Components (light and heavy). Light components mainly include dissolved gases (e.g., CO), dimethyl ether, methyl formate, and acetone. Heavy components include...

Ends include higher alcohols, long-chain hydrocarbons, higher ketones and

Esters of lower alcohols.

The impurities in crude methanol are generally separated in two stages. First, all components that are present at a lower temperature than

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Methanol is boiled and removed in a light-boiling column. The pure methanol is then distilled overhead in one or more distillation columns. If the columns operate at different pressures, the heat of condensation of the vapors can be used to reduce the methanol content.

Column operating at higher pressure, for heating the column with lower pressure

Pressure can be used.

Some components form azeotropic mixtures with methanol, e.g. acetone,

Ethyl formate, methyl acetate, ethyl acetate and methyl propionate.

This proposed configuration, with the extraction of a partial stream of the

Methanol synthesis and feeding at least a portion of the partial stream into the

Carburetors are also permitted in gasification technologies/processes where CO is used as

Since the feed gas used for the feedstock can be used, CO separation can be reduced or even eliminated, as the unreacted gas from methanol synthesis can be used as the feed gas. The need to provide less CO means that less solvent is required in the CO₂ stage.

A separation device is not required, thus reducing the energy needed for regeneration. Furthermore, CO₂ compression is also eliminated.

Gas flow to the operating pressure of the carburetor if it is operated at increased pressure.

Further preferred embodiments of the invention result from the other features mentioned in the dependent claims.

In a first embodiment of the method according to the invention, it is provided that at least a part of the partial flow is removed in the flow direction before the

Methanol synthesis is introduced. In this way, a recycling loop is created, whereby only a portion is returned to the reactor and, according to the invention, a portion is directed back to the gasifier and/or pyrolysis furnace. The cycle flow is not entirely fed to the methanol reactor, but partially to the biomass gasification. In the gasification process, certain components such as hydrocarbons are used for

Part of it is converted into synthesis gas. The gas then passes into the...

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Synthesis gas produced from biomass or waste is fed into the

Gas processing and is finally fed into methanol synthesis.

Depending on the conditions and specifications of the process, i.e., the procedure or the plant, the ratio between the portion of the partial stream that is fed into the methanol synthesis without further treatment or intermediate operations and the portion of the partial stream that goes into the

The ratio of the portion of the partial stream (low in methanol and hydrogen) that is directed to the gasifier and/or pyrolysis furnace to the portion of the partial stream directed to methanol synthesis is preferably less than 1, preferably less than 0.5, and particularly preferably less than 0.1.

In a further embodiment of the inventive method, it is provided that the partial stream is filtered into a

methanol recovery unit is directed, whereby in the

Methanol recovery unit: a methanol-laden stream and a methanol-poor stream

Partial stream is produced. The methanol recovery unit is, in particular, a methanol scrubbing column.

Furthermore, in a further embodiment of the invention

The process is designed so that the methanol-laden stream is directed to distillation. This advantageous configuration allows methanol to be separated from this methanol-containing stream as a valuable product.

In addition, a further embodiment of the method according to the invention may provide that the partial flow is filtered before being fed into the carburetor and/or

The hydrogen is fed from the pyrolysis furnace into a hydrogen recovery unit.

The hydrogen recovery unit can be combined with the methanol recovery unit, with the hydrogen recovery unit being the

The methanol recovery unit can be installed upstream or downstream.

The hydrogen recovery unit produces a hydrogen-rich stream and a hydrogen-poor partial stream, with the hydrogen-rich stream being the

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is fed into the methanol synthesis process. The unreacted synthesis gas contains, after the

Separation of crude ethanol, methanol, and a larger proportion of

Hydrogen. The methanol content can be significantly reduced by washing.

The hydrogen can be separated using hydrogen recovery and the

The methanol reactor can be fed directly. For hydrogen recovery, the following two technologies are particularly suitable: membrane processes and

Pressure swing adsorption (PSA).

In a further preferred embodiment of the inventive process, it is provided that a hydrogen stream and a

An oxygen flow is generated and that the hydrogen flow is upstream of the

methanol synthesis or is introduced into methanol synthesis and that the

An oxygen flow, or a partial flow, is introduced into the carburetor. To...

To increase carbon yield, it is advisable to add external hydrogen, for example from water electrolysis. In a plant configuration with

Water electrolysis can utilize the oxygen produced during the splitting of water.

Gasification can be used. Then there is no other oxygen source needed.

An example from an air separation plant (ASU) is necessary.

In a further advantageous embodiment of the inventive method, it is provided that an oxygen stream is generated by means of air separation, which is then fed into the

The gas is introduced via a carburetor. Without water electrolysis, additional oxygen can be added using an air separation unit (ASU). This can be advantageous if no external hydrogen is required.

The aforementioned task is also solved by a plant for the production of

Methanol from a carbon-containing feedstock, comprising at least the following components: a device for processing the carbon-containing feedstock

feedstock; a gasifier for gasification and/or a pyrolysis furnace for

Pyrolysis of the processed carbon-containing feedstock, to obtain a

raw synthesis gas:; a facility for processing the raw synthesis gas to

Obtaining synthesis gas; a methanol synthesis facility for obtaining

Crude ethanol; a distillation process for distilling crude ethanol to obtain

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Methanol and at least one byproduct; a recycling from the

Methanol synthesis equipment for use with a carburetor and/or

Pyrolysis furnace. The plant for the production of methanol is set up and configured to carry out a process according to the invention. The previous

Statements concerning the method according to the invention also apply accordingly to the plant according to the invention.

In a first embodiment of the plant according to the invention, a methanol recovery unit is provided in the return path, wherein in the

The methanol recovery unit produces a methanol-laden stream and an initial methanol-poor partial stream.

In a further embodiment of the inventive system, a

A hydrogen recovery unit is provided, wherein the

Hydrogen recovery unit fluid-technical with the

is connected to the methanol recovery unit and the methanol synthesis facility.

Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another.

The invention is described below in exemplary embodiments with reference to the associated

The drawings are explained. They show:

Figure 1 shows a schematic representation of an embodiment of a

Plant or process for the production of

Methanol from biomass

Figure 2 shows a schematic representation of an exemplary embodiment of an optimized plant or process for the production of methanol from biomass,

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Figure 3 shows a schematic representation of a further embodiment of an optimized system or method for

Production of methanol from biomass and

Figure 4 shows a schematic representation of a further embodiment of an optimized plant with a methanol and

Hydrogen recovery.

Figure 1 schematically shows a process or plant 1 for the production of methanol from a carbon-containing feedstock. First, in a

Equipment for processing 2 at least one carbon-containing input material, in this case biomass, biological material or carbon-rich material

The material is prepared for further processing. After processing step 2, the

Biomass is gasified in a gasifier 3 and/or pyrolyzed in a pyrolysis furnace (not shown), yielding a raw synthesis gas. This raw synthesis gas is treated in a raw synthesis gas processing unit 4 to produce a

to obtain synthesis gas. The synthesis gas is then used in a facility for

Methanol synthesis 5, which includes at least one reactor 6, converts the raw material to methanol or crude methanol. The crude methanol leaving reactor 6 contains water and other impurities. Therefore, a distillation unit 7 is provided downstream of reactor 6 to obtain pure methanol. During distillation 7, byproducts, process water, and unreacted substances are thermally separated from the methanol.

In the present embodiment, a water electrolysis unit 8 is additionally provided, which supplies oxygen for the carburetor and hydrogen for the

Methanol synthesis. N₂ or CO₂ is typically used as the carrier gas for the biomass. Some gasification technologies do not use a carrier gas.

Figure 2 shows an optimized process or plant 1 for the production of methanol from a carbon-containing feedstock. For the provision of

In this embodiment, an air separation unit (ASU) 9 is provided, which supplies oxygen to the carburetor 3.

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Furthermore, a recirculation system 10 is provided through which a partial stream is taken from the methanol synthesis unit 5. In the present embodiment, the partial stream is divided a further time, so that a portion of the partial stream is returned directly to the methanol synthesis unit 5 without further processing, while another portion of the partial stream is directed to the gasifier 3. The recirculation into the

Carburetor 3 allows for a reduction or even elimination of CO separation, as the unreacted gas from methanol synthesis can be used as a carrier gas. CO as a carrier gas from the processing unit of the

Raw synthesis gas 4 is therefore no longer necessary and is only shown with a dashed line. The need to provide less CO means that less solvent is required in the CO separation device, and thus less energy is needed for regeneration.

Furthermore, compression of the CO gas flow to the operating pressure of the carburetor is also eliminated if it is operated at increased pressure.

The circulating flow is not entirely directed to the methanol reactor, but partially to the

Biomass gasification is carried out. In gasifier 3, certain components such as

Hydrocarbons are partially converted into synthesis gas. This gas is then combined with the gas produced from biomass or waste during the gasification process.

Synthesis gas is fed into the gas processing unit and ultimately into the methanol synthesis process. This depends on the conditions and specifications of the process, i.e., the

The process or the facility can alter the relationship between the part of the

Partial stream that is fed into the methanol synthesis unit 5 without further treatment or intermediate operations and which is part of the

The partial flow that is directed into the carburetor can be adjusted. In the present case

An exemplary embodiment is the quantitative ratio between the part of the

Partial flow that is directed into carburetor 3, and the part of the partial flow that goes into the

The facility for methanol synthesis 5 is directed, smaller than 1.

Figure 3 shows a configuration that largely corresponds to the embodiment according to

Figure 2 is the same. However, instead of the air separation unit 9, a

Water electrolysis 8 is used, whereby the resulting oxygen is at least partially in

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The methanol synthesis device 5 is introduced into the process.

Figure 4 shows a configuration in which the portion of the partial flow that enters carburetor 2

The ethanol is first fed back into a methanol recovery unit 11 in the form of a methanol scrubbing column, where in the

Methanol recovery unit 11 a methanol-laden stream in the form of a

A water-methanol mixture and a low-methanol partial stream are produced. Additionally, downstream of the methanol recovery unit 11, the low-methanol partial stream is provided for in a [missing information] before being fed into the carburetor.

The hydrogen is directed to hydrogen recovery unit 12, producing a hydrogen-rich stream and a hydrogen- and methanol-poor partial stream, with the hydrogen-rich stream being fed to methanol synthesis 5. The unreacted

Synthesis gas, after the separation of crude methanol, still contains methanol and a significant proportion of hydrogen. The methanol content can be significantly reduced by scrubbing. The hydrogen can be separated using hydrogen recovery and fed directly into the methanol synthesis process. For the

The following two technologies are particularly suitable for hydrogen recovery:

Membrane processes and pressure swing adsorption (PSA).

Furthermore, Figure 4 shows that the water-methanol mixture is fed into distillation 7. This results in a total of four possible recycling streams. An internal

Recycled stream, which is fed back into methanol synthesis 5 untreated. A

Recycled stream that directs the methanol-water mixture into the distillation unit for methanol separation; a hydrogen-rich stream that passes through the

Hydrogen recovery unit 12 obtains the hydrogen, which can be fed into methanol synthesis 5, and an external recycling stream is part of the partial stream that is returned to the gasifier. This stream is low in hydrogen and methanol.

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Reference List 1 Plant 2 Processing of a carbon-containing feedstock 3 Gasifier 4 Raw synthesis gas processing plant 0 5 Methanol synthesis plant 6 Reactor 7 Distillation 8 Water electrolysis 9 Air separation unit (ASU) 10 Recirculation 11 Methanol recovery unit 12 Hydrogen recovery unit

Claims (10)

230566 P00LU 09.10.2024 LU103406 Patent claims 1. A process for producing methanol from a carbon-containing feedstock, comprising at least the following steps: a. Processing of at least one carbon-containing feedstock; b. Gasification in a gasifier (3) and/or pyrolysis in a pyrolysis furnace of the processed carbon-containing feedstock to obtain a raw synthesis gas; C. Processing of the raw synthesis gas to obtain synthesis gas; d. Methanol synthesis (5) to obtain crude methanol; e. Distillation of the crude methanol to obtain methanol and at least one by-product: f. Extraction of a partial stream from the methanol synthesis (5) and feeding at least a part of the partial stream into the gasifier and/or the pyrolysis furnace. 2. Method according to claim 1, characterized in that at least one part of the partial stream is introduced in the flow direction prior to the methanol synthesis (5). 3. Method according to claim 1 or 2, characterized in that the partial stream is directed into a methanol recovery unit (11) before being fed into the gasifier (3) and/or pyrolysis furnace, wherein a methanol-loaded stream and a methanol-poor partial stream are generated in the methanol recovery unit. 4. Method according to claim 3, wherein the methanol-loaded stream is directed to distillation (7). 230566 P00LU 09.10.2024 -2- LU103406 5. Method according to one of claims 1 to 4, characterized in that the partial stream is directed into a hydrogen recovery unit (12) before being fed into the gasifier (3) and/or pyrolysis furnace, whereby a hydrogen-rich stream and a hydrogen-poor partial stream are produced and wherein the hydrogen-rich stream is fed to the methanol synthesis (5). 6. Method according to one of claims 1 to 5, characterized in that a hydrogen stream and an oxygen stream are generated by means of water electrolysis (8) and that the hydrogen stream is introduced upstream of the methanol synthesis or into the methanol synthesis and that at least a part of the oxygen stream is introduced into the gasifier. 7. Method according to one of claims 1 to 5, characterized in that an oxygen stream is generated by means of air separation and introduced into the carburetor (3). 8. Plant (1) for the production of methanol from a carbon-containing feedstock, comprising at least the following components: a. a facility for the processing (2) of at least one carbon-containing feedstock; b. a gasifier (3) for gasification and/or a pyrolysis furnace for pyrolysis of the processed carbon-containing feedstock to obtain a raw synthesis gas; C. a device for processing the raw synthesis gas (4) to obtain a synthesis gas; d. a methanol synthesis apparatus (5) for the production of crude methanol; e. a distillation (7) to distill the crude methanol to obtain methanol and at least one by-product; f. a return (10) from the methanol synthesis facility (5) to the gasifier and/or pyrolysis furnace. 230566 P00LU 09.10.2024 -3- LU103406 9. Plant (1) according to claim 8, characterized in that a methanol washing column (11) is provided in the return (10), wherein a methanol-loaded stream and a methanol-poor partial stream are generated in the methanol recovery unit (11). 10. Plant (1) according to claim 8 or 9, characterized in that a hydrogen recovery unit (12) is provided, and that the hydrogen recovery unit (12) is fluidically connected to the methanol recovery unit (11) and the methanol synthesis apparatus (5).