Methanol synthesis plant, and process for synthesising methanol

Abstract

The invention relates to a methanol synthesis plant (24) and to a process (86) for synthesising methanol (50). The methanol synthesis plant (24) comprises at least one hydrogen source (84), a carbon oxide source (85), a methanol synthesis reactor (30), a jet pump (10), and a low-pressure steam source. The methanol synthesis reactor (30) is designed to catalytically convert hydrogen and carbon oxide at least in part into methanol (50) and to provide same at least proportionally as a reactor product flow (32). The jet pump (10) receives a motive steam flow (18), based at least on a coolant flow (58), and at least one suction steam flow (20), based on a low-pressure steam flow (76) ensured by the low-pressure steam source. The suction steam flow (20) has a lower pressure than the motive steam flow (18). The jet pump (10) is designed to ensure a mixed steam flow (22) based on the motive steam flow (18) and the suction steam flow (20), which mixed steam flow has a higher pressure than the suction steam flow (20) and can be used as an energy source.

Description

[0001] Methanol synthesis plant and process for the synthesis of methanol

[0002] The invention relates to a methanol synthesis plant and a process for the synthesis of methanol.

[0003] Methanol is an important basic chemical used in the synthesis of higher or functionalized hydrocarbons and as a solvent. For example, methanol serves as a starting material for the production of formaldehyde, formic acid, and acetic acid.

[0004] Methanol is typically produced in a methanol synthesis reactor. A stream of synthesis gas containing hydrogen and carbon oxides is fed into the reactor. An exothermic chemical reaction takes place within the reactor to produce methanol. Synthesis gas can be used in a process-related process upstream of the reactor.

[0005] Synthesis gas reactor arrangements can be used to produce synthesis gas. For example, carbon-containing gases (i.e., carbon-containing energy carriers) such as natural gas or biogas can be converted into synthesis gas. The synthesis gas reactor arrangement and the methanol synthesis reactor can together form a plant for the synthesis of methanol (methanol synthesis plant).

[0006] Methods for the synthesis of methanol are described, for example, in the publication EP 3 491 173 Al, which forms the technological background of the invention.

[0007] Methanol synthesis processes and related plants often have energy requirements that must be met by external energy sources. Complex process engineering systems can reduce this requirement, but they necessitate sophisticated and expensive equipment. Conventional low-pressure steam sources, such as those sometimes found at plant sites, provide steam at a pressure level too low (below 6 bar) to be used for operating the methanol synthesis plant, and especially its distillation section. The distillation section, in particular, as the largest energy sink, typically requires multiple reboilers for start-up, shutdown, and normal operation, thus increasing the plant's complexity. For example, the use of electric reboilers results in high electricity costs.

[0008] There is therefore a need to eliminate or at least reduce the disadvantages of known methanol synthesis processes and plants. In particular, there is a need to create a methanol synthesis process and plant that enable a reduction in production costs through energy optimization.

[0009] The problem is solved by the subject matter of the independent claims. Advantageous embodiments are specified in the dependent claims and the subsequent description, each of which, individually or in (sub-)combination, can represent aspects of the disclosure. Some features are explained with regard to methods, others with regard to apparatus. However, the aspects are interchangeable in a corresponding manner.

[0010] According to one aspect, some embodiments of the invention relate to a methanol synthesis plant. The methanol synthesis plant comprises at least a hydrogen source, a carbon oxide source, a methanol synthesis reactor, a jet pump, and a low-pressure steam source.

[0011] The methanol synthesis reactor is set up to catalytically convert hydrogen supplied by the hydrogen source and carbon oxide supplied by the carbon oxide source at least partially to methanol and to provide at least a proportion of it as a reactor product stream.

[0012] The jet pump receives at least one motive steam stream at a first inlet, based on at least one coolant stream from the methanol synthesis reactor. At a second inlet, the jet pump receives at least one suction steam stream, based on a low-pressure steam stream provided by the low-pressure steam source. The suction steam stream has a lower pressure than the motive steam stream. The jet pump is configured to provide a mixed steam stream based on the motive steam stream and the suction steam stream, which has a higher pressure than the suction steam stream. The mixed steam stream can be used as an energy source. The invention utilizes the effect of the jet pump, which can increase the pressure and / or temperature levels of the suction steam stream by means of the motive steam stream. The resulting mixed steam stream can then be used as an energy carrier, particularly for energy-intensive components of the methanol synthesis plant.Low-pressure steam, which is generally available at the production site but previously unusable in the methanol synthesis process due to insufficient pressure and temperature levels, can now be used as an energy carrier. This improves the overall energy balance of the methanol production process. In other words, production costs can be reduced, for example, because electricity consumption can be lowered by reducing the number of electrically operated heating devices compared to previous methods.

[0013] Advantageously, in the methanol synthesis plant, an internally generated steam stream is used as the motive steam stream. This steam stream can be based on a coolant stream from the methanol synthesis reactor. The coolant stream of the methanol synthesis reactor serves to remove the heat of reaction from the exothermic synthesis reaction and thus regulate the reaction conditions within the reactor. As a result, few or no additional components are required to provide the motive steam stream. In particular, the generation of the motive steam stream can be integrated into the existing coolant circuit. The motive steam stream generated from the coolant stream of the methanol synthesis reactor can be used completely or partially in the jet pump. This ensures the efficient functionality of the jet pump and the generation of the mixed steam stream as an energy carrier.

[0014] According to one aspect, some embodiments of the invention relate to a process for the synthesis of methanol. The process comprises at least the following steps:

[0015] Hydrogen is supplied by a hydrogen source.

[0016] Carbon oxide is supplied by a carbon oxide source. A reactor product stream from a methanol synthesis reactor is provided. The reactor product stream contains at least a proportion of methanol catalytically reacted from hydrogen and carbon oxide.

[0017] A motive steam stream is received at a first inlet of a jet pump based on at least a coolant stream from the methanol synthesis reactor.

[0018] The coolant flow can be at least partially liquid and / or gaseous. It can therefore also include a mixture of liquid and gaseous components. This increases the variability.

[0019] A suction steam stream is received at a second inlet of a jet pump, based at least on a low-pressure steam stream provided by a low-pressure steam source. The suction steam stream has a lower pressure than the motive steam stream.

[0020] A mixed steam stream is provided by the jet pump based on the motive steam stream and the suction steam stream. The mixed steam stream has a higher pressure than the suction steam stream.

[0021] The mixed steam stream is used as an energy source.

[0022] The advantages achieved by the previously described methanol synthesis plant are similarly achieved by the methanol synthesis process presented here.

[0023] The methanol synthesis plant described here is not limited to those components, such as reactors, that are necessary for the methanol synthesis process itself. Rather, the methanol synthesis plant also includes additional components, which, for example, are used to distill off methanol from the reactor product stream. Similarly, the process for synthesizing methanol is not limited to the synthesis process itself, but also encompasses further aspects, such as the distillation of methanol from a process stream.

[0024] The methanol synthesis plant is also robust thanks to the use of a jet pump. This is because a jet pump generally has no (or at most very few) moving parts. The pumping action is generated by the fluid jet of the motive steam stream exiting a nozzle, the motive steam nozzle. Due to Bernoulli's principle, this exit creates a vacuum in the downstream mixing chamber. Here, the motive steam stream exiting the nozzle meets the suction steam stream, generating turbulent flow. The vacuum draws in the suction steam stream, accelerates it, and compresses it. This effect is based on momentum transfer from the motive steam stream to the suction steam stream, driven by the vacuum created and the turbulent flow. As a result, the resulting mixed steam stream has a higher pressure than the suction steam stream.

[0025] Preferably, the jet pump can be an ejector, i.e., a jet pump that generates a negative pressure, particularly with regard to the suction steam flow.

[0026] Optionally, the mixed steam stream is also used as an energy source for other internal components of the methanol synthesis plant.

[0027] Alternatively or cumulatively, the mixed steam stream can also be used as an energy source for components that are external to the methanol synthesis plant.

[0028] This will further improve the energy balance of the methanol synthesis plant. For example, the demand for electrical energy can be further reduced.

[0029] In some embodiments, the pressure and / or temperature of the mixed steam flow provided by the at least one jet pump can be adjusted and thus varied based on a variation of at least one pressure or temperature of the motive steam flow and / or the suction steam flow and / or a quantity ratio of the motive steam flow to the suction steam flow. This allows the energy content of the mixed steam flow to be adjusted as required, so that the corresponding power requirements of components of the methanol synthesis plant can be met, and optionally also of other components.

[0030] Optionally, the coolant stream of the methanol synthesis reactor can be fed into a steam drum. The steam drum is configured to separate a gaseous portion of the coolant stream as a motive steam stream. In other words, the coolant stream of the methanol synthesis reactor can be a two-phase mixture, specifically comprising a gaseous and a liquid coolant stream. The gaseous portion, used as motive steam for the jet pump, can then be separated from the liquid coolant stream by means of at least one steam drum. This enables a particularly compact and efficient supply of the motive steam stream.

[0031] In some embodiments, the steam drum is also configured to separate a partial coolant stream, containing at least liquid coolant, from a two-phase coolant stream. The methanol synthesis plant has a coolant feed for the partial coolant stream, through which the liquid partial coolant stream can be returned to the methanol synthesis reactor.

[0032] In general, well-defined reactor parameters for methanol synthesis must be maintained in the methanol synthesis reactor, for example, with regard to temperature. These parameters can be ensured by the continuously circulating coolant. Coolant recirculation allows for at least partial reuse of the coolant from the steam drum. Therefore, the energy integration of the methanol synthesis plant is particularly high.

[0033] Preferably, the methanol synthesis plant comprises at least several methanol synthesis reactors. Each methanol synthesis reactor is configured to ensure and provide a coolant flow, at least partially (with respect to its gaseous component) of which can be supplied as a motive steam flow to at least one jet pump. This ensures redundancy with respect to the motive steam flow. Additionally, the different coolant flows and / or heating elements allow for motive steam flows with different pressures and / or temperatures and / or variable ratios of vapor / liquid mixtures. This also allows the energy content of the generated mixed steam flow to be adjusted. Advantageously, the productivity of the methanol synthesis plant per unit of time can also be increased by using multiple methanol synthesis reactors. Thus, more methanol can be produced per unit of time.

[0034] Alternatively, the energy content of the mixed steam stream can be adjusted by changing the ratio of the motive steam stream to the suction steam stream. Another alternative is a two-stage methanol synthesis reactor. In this case, for example, only the first stage of the methanol synthesis reactor could be configured to provide a coolant stream, such as a boiling water-cooled tube bundle reactor. The second stage could then be configured as an adiabatic reactor that does not itself provide or supply any (additional) coolant stream.

[0035] In some embodiments, the methanol synthesis plant comprises multiple jet pumps. Each jet pump is configured to provide at least one motive steam stream at a first inlet, based on at least one coolant stream from a methanol synthesis reactor. Furthermore, each jet pump is configured to provide at least one suction steam stream at a second inlet, based on at least one low-pressure steam stream supplied by at least one low-pressure steam source. Additionally, each jet pump is configured to provide a mixed steam stream based on the respective motive steam stream and the respective suction steam stream. The methanol synthesis plant is further configured such that the pressures and / or temperatures of the mixed steam streams provided separately by the multiple jet pumps are either equal or different from one another.This creates further redundancy, specifically regarding the multiple mixed steam streams generated and supplied by the different jet pumps. Additionally, different mixed steam streams can exhibit different properties, allowing mixed steam streams with varying energy content to be supplied simultaneously for different applications or components.

[0036] In some embodiments, the methanol synthesis plant also includes a distillation section. The distillation section is designed to distill off at least a portion of the methanol from the reactor product stream. The mixed steam stream can be used, at least as an energy source, for the distillation section. Since the distillation section represents a large energy sink for the methanol synthesis plant, the energy integration of the plant can be further increased.

[0037] Preferably, the multiple suction steam streams are fluidically coupled to each other via a suction steam rail or can be fed separately to different jet pumps. In some embodiments, the multiple motive steam streams are fluidically coupled to each other via a motive steam rail or can be fed separately to different jet pumps.

[0038] The shared suction steam / motive steam rail improves the consistency of the supply with at least one suction steam / motive steam stream. In particular, the supplied suction steam / motive steam stream can be subject to minor fluctuations in its pressure and / or temperature.

[0039] Optionally, at least one heating element is coupled to at least the steam drum and a methanol synthesis reactor. The heating element is designed to at least indirectly increase the amount of motive steam supplied to a jet pump. The heating element can evaporate coolant, which is then fed to the steam drum. In this way, the motive steam flow can be indirectly influenced. The heating element can therefore also be coupled, at least indirectly, to both the methanol synthesis reactor and the steam drum for generating the motive steam flow. The energy content of the mixed steam flow can then be adjusted by changing the ratio of the motive steam flow to the suction steam flow. Additionally, the amount of steam generated by the heating element can eliminate the need for other components, such as electric reboilers. This reduces the necessary investment costs for implementing the methanol synthesis plant.

[0040] The temperature of the coolant flow can be reduced to a minimum temperature by the heating element, especially when starting up the methanol synthesis reactor, so that the reaction conditions can be ensured.

[0041] Preferably, the heating element is an electric heating element. This allows the heat output to be controlled and regulated particularly easily.

[0042] Optionally, several heating elements can be coupled to at least one coolant stream and / or a methanol synthesis reactor. This ensures redundancy and increases the amount of heat delivered. Optionally, the methanol synthesis plant includes at least one heat exchanger as part of the low-pressure steam source. The heat exchanger is fluidically coupled to the methanol synthesis reactor, at least indirectly. Preferably, the heat exchanger is used to cool the reactor product stream. The heat exchanger is configured to provide a low-pressure steam stream as a suction steam stream at one inlet of at least one jet pump. In other words, this increases the energy integration of the methanol synthesis plant.

[0043] In particular, the low-pressure steam flow can be based on a coolant flow. This means that a process gas flow, which is to be cooled for further processing, can be used to generate a coolant flow that, in the form of the low-pressure steam flow, can be used as a suction steam flow for at least one jet pump.

[0044] Preferably, the low-pressure steam source is configured to provide an external steam supply in the form of the low-pressure steam flow for the methanol synthesis plant as a suction steam flow at one inlet of at least one jet pump. This increases the variability in supplying the suction steam flow.

[0045] In particular embodiments, the motive steam flow at the inlet of the jet pump can have a pressure in the range of 10 bara (bara: bar absolute) to 45 bara and a temperature in the range of 200°C to 280°C, preferably a pressure in the range of 25 bara to 42 bara and a temperature in the range of 230°C to 250°C, more preferably a pressure in the range of 29 bara to 40 bara and a temperature in the range of 230°C to 250°C.

[0046] Preferably, the suction steam flow at the inlet of the jet pump can have a pressure in the range of 2 bara to 6 bara and a temperature in the range of 120°C to 250°C, preferably a pressure in the range of 2.7 bara to 4.5 bara and a temperature in the range of 140°C to 210°C.

[0047] Optionally, the mixed steam stream at the outlet of the jet pump can have a pressure in the range of 4 bara to 12 bara and a temperature in the range of 130°C to 200°C, preferably a pressure in the range of 5.5 bara to 9 bara and a temperature in the range of 155°C to 175°C. In some embodiments, the mixing ratio of the motive steam stream to the suction steam stream in the jet pump is between 0.5 and 9, preferably between 1 and 6.

[0048] In a first particular embodiment, the mixture ratio of the motive steam stream to the suction steam stream in the jet pump can be between 2 and 3.5, preferably between 2.5 and 2.8.

[0049] In a second special embodiment, the mixture ratio of the motive steam stream to the suction steam stream in the jet pump can be between 1 and 2, preferably between 1.2 and 1.7.

[0050] The different mixing ratios of substances allow the processes for the synthesis of methanol to be adapted to the needs of the respective methanol synthesis plant.

[0051] The mixing ratio can refer to a volume ratio or a weight ratio.

[0052] Based on the parameters selected in this way, the methanol synthesis plant exhibits a particularly high level of energy integration and production efficiency.

[0053] Preferably, the hydrogen source includes an electrolyzer. The electrolyzer is configured to produce hydrogen. In particular, the electrolyzer can be operated with electrical energy generated from renewable energy sources. The electrolyzer enables the efficient production of hydrogen at a consistent rate. Operating the system on renewable energy sources improves the environmental footprint of the methanol synthesis plant.

[0054] In some embodiments, the methanol synthesis plant includes at least one separator. The separator is designed to separate methanol-containing components from the reactor product stream. Additionally, the separator is designed to provide the methanol-containing components for the distillation section.

[0055] Optionally, the methanol synthesis reactor can be a boiling water-cooled tube bundle reactor. This ensures a particularly consistent operating temperature during methanol synthesis. Preferably, the coolant is water. In this case, no special requirements are placed on the coolant delivery system. Conventional equipment and delivery components can be used.

[0056] In one embodiment, a residual stream of the reactor product stream downstream of the distillation section can also be used as fuel gas, particularly for energy generation, for example in the case of natural gas-based methanol synthesis plants.

[0057] All features explained with regard to the various aspects can be combined individually or in (sub-)combination with other aspects.

[0058] The disclosure, as well as further advantageous embodiments and developments thereof, are described and explained in more detail below with reference to the examples shown in the drawings. These show:

[0059] - Fig. 1 a simplified schematic representation of a jet pump of the methanol synthesis plant according to an embodiment of the invention,

[0060] - Fig. 2 a simplified schematic representation of a methanol synthesis plant according to an embodiment of the invention,

[0061] - Fig. 3 a simplified schematic representation of a

[0062] Methanol synthesis plant according to a further embodiment of the invention,

[0063] - Fig. 4 a simplified schematic representation of a

[0064] Methanol synthesis plant according to a further embodiment of the invention, and

[0065] - Fig. 5 a simplified schematic representation of a process for the synthesis of methanol according to an embodiment of the invention.

[0066] The detailed description below, in conjunction with the accompanying drawings, in which identical numbers refer to identical elements, is intended to describe various embodiments of the disclosed subject matter and is not meant to represent the only embodiments. Each embodiment described in this disclosure serves only as an example or illustration and should not be construed as preferable or advantageous over other embodiments. The illustrative examples contained herein do not claim to be exhaustive and do not limit the claimed subject matter to the exact forms disclosed. Various modifications of the described embodiments are readily apparent to the person skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the described embodiments.Therefore, the described embodiments are not limited to the embodiments shown, but have the broadest possible scope of application that is compatible with the principles and features disclosed here.

[0067] All features disclosed below with reference to the exemplary embodiments and / or the accompanying figures can be combined alone or in any subcombination with features of the aspects of the present disclosure, including features of preferred embodiments, provided that the resulting combination of features is meaningful to a person skilled in the art.

[0068] For the purposes of this disclosure, the phrase "at least one of A, B and C" means, for example, (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C), including all other possible combinations where more than three elements are listed. In other words, the term "at least one of A and B" generally means "A and / or B", namely "A" alone, "B" alone, or "A and B".

[0069] Fig. 1 shows a simplified schematic representation of a jet pump 10 of the methanol synthesis plant according to an embodiment of the invention.

[0070] The jet pump 10 is designed as an ejector 12. This means that the jet pump 10 exerts a predominantly suction effect (pump action). The temperature and pressure levels are shown on the y-axis 14 in relation to the mixed steam generation on the x-axis 16.

[0071] At a first inlet, the ejector 12 receives a motive steam 18 (also called motive steam stream). The motive steam 18 can be supplied within the methanol synthesis plant, for example, by a methanol synthesis reactor. At a second inlet, the ejector 12 receives a suction steam 20 (also called suction steam stream). The suction steam 20 can be supplied within the methanol synthesis plant, for example, by a low-pressure steam source.

[0072] The motive steam 18 and the suction steam 20 differ in their physical properties with regard to the respective pressure and / or temperature.

[0073] In the present embodiment, the motive steam 18 has, by way of example, a pressure between 29 bar and 40 bar (absolute bar) and a temperature between 232°C and 250°C.

[0074] In contrast, the suction steam 20 generally has a significantly lower pressure, in particular less than 6° bara. In this example, the suction steam 20 has a pressure in the range between 2.7 bara and 4.5 bara and a temperature in the range between 140°C and 210°C.

[0075] Within the ejector 12, the motive steam 18 is passed through a motive steam nozzle and atomized. Due to the Bernoulli effect, a vacuum is created at the outlet of the motive steam nozzle. This draws in the suction steam 20. A turbulent flow is generated from a mixture of the motive steam 18 and the suction steam 20. Due to the turbulent flow and the generated vacuum, momentum is transferred from the motive steam 18 to the suction steam 20. The mixed steam 22 is provided at an outlet of the ejector 12 (also called the mixed steam stream). As a result of the momentum transfer, the mixed steam 22 has a pressure that is higher than the pressure of the suction steam 20. According to this embodiment, the mixed steam 22 has, for example, a pressure between 5.5 bara and 9 bara and a temperature between 155°C and 175°C.

[0076] By increasing the pressure of the generated mixed steam 22 compared to the suction steam 20, the energy content of the mixed steam 22 per unit volume or quantity is increased compared to the energy content of the suction steam 20. As a result, the generated mixed steam 22 can be used as an energy source in a process plant that requires a higher pressure and temperature level than is present in the suction steam, for example, in a methanol synthesis plant. In particular, the energy content of the mixed steam 22 can be adjusted so that the generated mixed steam 22 can be used as an energy source for a distillation section of the methanol synthesis plant. This advantageously eliminates the need for electrical energy (or reduces the amount) to be used for the methanol distillation process.Based on this concept, the energy integration of the methanol synthesis plant can be improved, which means a reduction in production costs and an increase in the efficiency of methanol production.

[0077] Fig. 2 shows a simplified schematic representation of a methanol synthesis plant 24 according to an embodiment of the invention.

[0078] According to this embodiment, the methanol synthesis plant 24 receives compressed synthesis gas 26 at an inlet. The synthesis gas 26 comprises at least unreacted hydrogen and unreacted carbon oxide, which are mixed and compressed together.

[0079] For the provision of the compressed synthesis gas 26, the methanol synthesis plant 24 can have a compressor (not shown here) to which uncompressed synthesis gas is initially supplied. The compressor can then compress the synthesis gas.

[0080] Starting at the inlet, the compressed synthesis gas 26 is fed to an inlet-outlet heat exchanger 28. The temperature of the compressed synthesis gas 26 can be increased by the inlet-outlet heat exchanger 28. The heated compressed synthesis gas 26 is then fed to the methanol synthesis reactor 30. The methanol synthesis reactor 30 is designed as a boiling water-cooled tube bundle reactor.

[0081] In methanol synthesis reactor 30, the unreacted hydrogen is catalytically reacted with the unreacted carbon dioxide to produce at least a portion of methanol. The conversion to methanol is generally based on an exothermic chemical reaction.

[0082] The reactor product stream 32 is fed to the inlet-outlet heat exchanger 28. Since the temperature of the reactor product stream 32 is elevated compared to the compressed synthesis gas 26 due to the exothermic reaction, the reactor product stream 32 can be used within the inlet-outlet heat exchanger 28 to ensure that the compressed synthesis gas 26 is heated for the reaction in the methanol synthesis reactor 30. In other words, energy is extracted from the reactor product stream 32 and transferred to the compressed synthesis gas 26 to increase its temperature.

[0083] The cooled reactor product stream 32 is then fed to a process cooler 34 to further reduce its temperature. Downstream, the reactor product stream 32 is then fed to a water cooler 36, which enables a further reduction in temperature.

[0084] In a downstream separator 38, methanol-containing components of the reactor product stream 32 are separated. This means that crude methanol, containing the main components methanol and water, is separated from the remaining components of the reactor product stream 32. The separated (methanol-containing) reactor product stream 32 is removed from the separator 38, generally as a two-phase mixture. The reactor product stream 32 is then fed to a distillation section 44.

[0085] The distillation section 44 has at least one, and generally several, methanol distillation stages 46. Each methanol distillation stage 46 is designed to distill off methanol 50 from the reactor product stream.

[0086] A residual stream 48 is fed back to the synthesis gas 26 downstream of the distillation section 44 via a recirculation 52, optionally upstream to a compressor used to compress the synthesis gas 26. This configuration is particularly advantageous for carbon dioxide-powered methanol synthesis plants 24. Alternatively, the residual stream 48 can be used for other purposes, such as combustion.

[0087] The purified methanol 50 is removed from the methanol synthesis plant 24 and can be used for a variety of application scenarios.

[0088] Downstream of the separator 38, according to the present embodiment of the methanol synthesis plant 24, gaseous components are recirculated in a recycling stream 54 for methanol synthesis. Purge gas 40 can be separated from the recycling stream 54 via a control valve (not shown). The purge gas 40 can, for example, be combusted, at least partially, as fuel gas, for example, also for energy production. As part of the recirculation process, the recycling stream 54 is fed to a recycling compressor 56 to increase its density. Subsequently, the compressed recycling stream 54 is fed to the compressed synthesis gas 26.

[0089] The distillation of methanol 50 within the distillation section 44 is an energy-intensive process that often accounts for the main (or at least a significant) portion of the energy consumption of the methanol synthesis plant 24. Therefore, it is desirable not to provide the required energy solely based on electrical energy. Rather, the energy integration of the methanol synthesis plant 24 can be increased by utilizing material streams that have a corresponding energy content. For this reason, the methanol synthesis plant 24 features a mixed steam generation system.

[0090] For this purpose, at least a portion of a two-phase coolant stream 58 is used, which results from the methanol synthesis reactor 30, which in this case is designed as a boiling water-cooled tube bundle reactor. This means that the methanol synthesis reactor 30 is continuously supplied with coolant 60.

[0091] In this embodiment, water 60 is used as the coolant, which is supplied at an inlet 62 of the methanol synthesis plant 24. According to this embodiment, the coolant 60 is fed directly to a steam drum 66 of the methanol synthesis plant 24 at inlet 62. Other arrangements are also possible.

[0092] The steam drum 66 provides a motive steam stream 18 at one outlet. The motive steam stream 18 is then supplied to a jet pump 10 (not shown here). Based on the jet pump 10, a mixed steam stream 22 can be generated, which is used as an energy source for the distillation section 44.

[0093] According to the present embodiment, the steam drum 66 is configured such that a partial coolant stream 72, comprising liquid coolant 60, preferably water, is recirculated within the methanol synthesis plant 24. This partial coolant stream 72 is fed to an electric heating element 64, where the coolant 60 is heated according to the required operating parameters of the steam drum 66 and the methanol synthesis reactor 30. The electric heating element 64 allows the methanol synthesis reactor 30 to be brought up to the desired operating temperature more quickly during start-up. During start-up, the partial coolant stream 72, preheated by the electric heating element 64, is fed into the methanol synthesis reactor 30 as a feed stream 65.

[0094] Under normal operating conditions, the electric heating element 64 is not required for the methanol synthesis reaction. However, the heating element 64 can be advantageously used to increase the motive steam flow 18. In this operating mode, the preheated partial coolant flow 68 is directly returned to the steam drum 66 and thus contributes to the motive steam production.

[0095] Coolant 60, which has flowed through the methanol synthesis reactor 30, is supplied to the steam drum 66 as a two-phase coolant stream 58. An additional partial coolant stream 68 from the electric heating element 64 can be supplied to the steam drum 66 to increase the amount of motive steam produced.

[0096] Additionally, the methanol synthesis plant 24 has a feed line 69 between the steam drum 66 and the feed stream 65. When the methanol synthesis reactor 30 is started up, the feed line 69 and the return line for the partial coolant stream 68 are closed, so that the coolant stream preheated by the electric heating element 64, preferably a water / steam mixture, is supplied to the methanol synthesis reactor 30.

[0097] In normal operation, the heating and cooling circuits of the methanol synthesis reactor 30 are decoupled from each other by closing valve 70, and the methanol synthesis reactor 30 is supplied with coolant via the supply line 69. If required, additional heat energy can be supplied to the steam drum 66 via the electric heating element 64 and the return line for the partial coolant flow 68. This allows the amount of motive steam produced to be adjusted as needed. Further valves, not shown, may be present for controlling the coolant flows.

[0098] For example, after the methanol synthesis reactor 30 has been started up, it may be possible to deactivate the electric heating element 64, since sufficient heat energy is generated during normal operation of the methanol synthesis reactor 30 due to the chemical reaction taking place within it. In this case, the electric heating element 64 no longer needs to be heated. The energy released during the chemical reaction can then be used to vaporize water. As a result, a water / steam mixture is drawn off at the reactor head (two-phase coolant flow 58). This water / steam mixture is then separated in the steam drum 66. At least the liquid water of the coolant 60 can then be returned to the methanol synthesis reactor 30 (feed flow 65), and the steam (motive steam flow 18) enters a steam collector.

[0099] During normal operation of the methanol synthesis reactor 30, it is also possible to generate additional steam using the electric heating element 64. In this process, water from the coolant 60 flows from the steam drum 66 into the electric heating element 64 via a separate line (partial coolant flow 72). The resulting water / steam mixture is then returned directly to the steam drum 66 (partial coolant flow 68), thus deviating from the procedure used when starting up the methanol synthesis reactor 30.

[0100] The steam from the two sources, namely the methanol synthesis reactor 30 and the electric heating element 64, is separated from the liquid water of the coolant 60 in the steam drum 66 and is available for further use, in particular as motive steam 18. The electric heating element 64 therefore offers, in particular, the possibility of increasing the amount of steam within the steam drum 66 and thus the amount of motive steam in the motive steam 18. The steam pressure can be regulated via a (separate) pressure control on the steam drum 66. The corresponding saturated steam temperature is then established. This temperature then also corresponds to the desired cooling temperature within the methanol synthesis reactor 30.

[0101] The methanol synthesis plant 24 can include general valve systems, pump systems, control and regulation systems.

[0102] Fig. 3 shows a simplified schematic representation of a methanol synthesis plant 24 according to a further embodiment of the invention. The embodiment shown here corresponds essentially to the embodiment shown in Fig. 2. Therefore, only the differences will be discussed here. In this case, a heat exchanger 74 in the form of a steam generator is used instead of the process cooler 34. The heat exchanger 74 serves to transfer heat from the reactor product stream 32 to a coolant 60. The coolant 60, in the form of water, is supplied to the heat exchanger 74, where it evaporates. As a result, a low-pressure steam stream 76 can be generated by the heat exchanger 74. This means that the low-pressure steam stream 76 is based on a coolant stream 77. Preferably, the generated low-pressure steam stream 76 has a pressure in the range of less than 6 bar absolute. The low-pressure steam stream 76 can then, for example, be supplied to the jet pump 10 as a suction steam stream 20.This further increases the energy integration of the methanol synthesis plant 24.

[0103] Fig. 4 shows a simplified schematic representation of a methanol synthesis plant 24 according to a further embodiment of the invention.

[0104] In connection with the different embodiments of the methanol synthesis plant 24, Fig. 5 shows a simplified schematic representation of a process 86 for the synthesis of methanol 50 according to one embodiment of the invention. Additional optional steps of the process 86 are shown in dashed lines and will become apparent from the figure descriptions and the remaining parts of the description and the claims.

[0105] According to the embodiment shown in Fig. 4, the methanol synthesis plant 24 comprises an electrolyzer 78 as a hydrogen source 84. The electrolyzer 78 is configured to carry out an electrolysis process, for example, water electrolysis. In particular, unreacted hydrogen can be provided by the electrolyzer 78.

[0106] Accordingly, method 86 includes step 88 in which hydrogen is provided by a hydrogen source 84. According to the present embodiment, the electrolyzer 78 acts as the hydrogen source.

[0107] Additionally, the process 86 includes step 90, which involves providing carbon oxide via a carbon oxide source 85. The provided carbon oxide can also include recycled carbon oxide via a previously described recycling stream 54. According to the present embodiment, the methanol synthesis plant 24 has a compressor 80 coupled to the electrolyzer 78 as the hydrogen source 84 and the carbon oxide source 85. The compressor 80 is configured to increase the pressure of the mixture of unreacted hydrogen and unreacted carbon oxide. This provides the compressed synthesis gas 26, which is subsequently fed to the methanol synthesis reactor 30.

[0108] Alternatively or cumulatively, the pressure of only one component of the mixture can be increased, for example, to match the pressure of another component. In this way, hydrogen can initially be pumped at low pressure and only compressed by the compressor 80.

[0109] Within the methanol synthesis reactor 30, the hydrogen and carbon oxide are catalytically reacted. Consequently, process 86 includes step 92, in which a reactor product stream 32 from the methanol synthesis reactor 30 is provided. The reactor product stream 32 contains at least a proportion of methanol 50. Subsequently, the reactor product stream 32 is fed to the heat exchanger 74.

[0110] At least one coolant stream 58 is used at least indirectly, for example by means of an intermediate steam drum 66, starting from methanol synthesis reactor 30, to supply a motive steam stream 18 to the jet pump 10, in accordance with step 94 of process 86.

[0111] The jet pump 10, preferably designed as an ejector 12, is supplied via a motive steam line 19, which is configured to accommodate several steam flows that together constitute the motive steam flow 18. For example, the methanol synthesis plant 24 can have several methanol synthesis reactors 30, each providing corresponding coolant flows 58 and supplying them to the jet pump 10. Similarly, a suction steam flow 20 is also supplied to the jet pump 10 via a suction steam line 21. The suction steam line 21 is configured to accommodate several steam flows that together constitute the suction steam flow 20.

[0112] Alternatively, several jet pumps 10 with respective motive steam rails 19 and suction steam rails 21 can be provided. Method 86 additionally includes step 96 in which a low-pressure steam flow 76 is supplied from the heat exchanger 74 to the suction steam rail 21 to ensure a suction steam flow 20.

[0113] According to the present embodiment, external steam 82 can alternatively or cumulatively be used as a low-pressure steam flow 76 to ensure the suction steam flow 20.

[0114] The motive steam stream 18 has a pressure that is higher than the pressure of the suction steam stream 20.

[0115] In accordance with step 98 of process 86, the jet pump 10 then provides a mixed steam stream 22 based on the motive steam stream 18 and the suction steam stream 20. The mixed steam stream 22 has a pressure that is higher than the pressure of the suction steam stream 20.

[0116] The mixed steam stream 22 generated by the jet pump 10 is used as an energy source in accordance with step 100 of process 86. Various components of the methanol synthesis plant 24 can then be supplied with energy from the mixed steam stream 22. This results in a particularly high level of energy integration for the methanol synthesis plant 24.

[0117] Starting from heat exchanger 74, the reactor product stream 32 is fed, at least indirectly, for example via a separator 38 and / or further heat exchangers 28, 36 (see Fig. 3), to the distillation section 44. Within the distillation section 44, methanol 50 is distilled from the reactor product stream 32 according to optional step 102 of process 86. The mixed steam stream 22 can, for example, be used as an energy source for distillation section 44.

[0118] Electric heating elements 64 can be used to heat the coolant flow 58, or alternatively to generate additional motive steam which can be supplied to the motive steam rail 19 to ensure the motive steam flow 18.

[0119] In a particular embodiment, an electric heating element 64 can, for example, be directly coupled to the motive steam rail 19. Due to the various embodiments of the methanol synthesis plant 24, the methanol synthesis plant 24 can be used in a variety of ways, depending on the specific infrastructural conditions at the plant site. A high degree of energy integration can be achieved, in which, in particular, the distillation section 44 can be supplied with energy, at least to a significant extent, by the mixed steam stream 22.

[0120] This creates a methanol synthesis plant 24 that can ensure high production efficiency, high variability and high production volume.

[0121] This application may refer to quantities and numbers. Unless expressly stated otherwise, such quantities and numbers are not to be considered limiting, but rather as examples of the possible quantities or numbers in connection with this application. In this context, the term "plural" may also be used in this application to refer to a quantity or number. In this context, "plural" means any number greater than one, e.g., two, three, four, five, etc. The terms "about," "approximately," "close," etc., mean plus or minus 5% of the stated value.

[0122] Although the disclosure has been presented and described in relation to one or more embodiments, the person skilled in the art will be able to make equivalent changes and modifications after reading and understanding this description and the accompanying drawings.

[0123] Reference symbol list

[0124] 10 jet pump

[0125] 12 ejector

[0126] 14 x-axis

[0127] 16 y-axis

[0128] 18 motive steam stream

[0129] 20 Suction steam flow

[0130] 22 Mixed steam flow

[0131] 24 Methanol synthesis plant

[0132] 26 Synthesis gas

[0133] 28 Inlet-outlet heat exchangers

[0134] 30 Methanol synthesis reactor

[0135] 32 Reactor product stream

[0136] 34 process coolers

[0137] 36 water coolers

[0138] 38 separators

[0139] 40 Purge gases

[0140] 44 Distillation section

[0141] 46 methanol distillation stages

[0142] 48 residual current

[0143] 50 Methanol

[0144] 52 Return 54 Recycling stream

[0145] 56 Recycle compressor

[0146] 58 Coolant flow

[0147] 60 Coolant

[0148] 62 Entrance

[0149] 64 Heating element

[0150] 65 Supply current

[0151] 66 Steam drum

[0152] 68 Partial coolant flow

[0153] 69 Supply line

[0154] 70 valve

[0155] 72 Partial coolant flow

[0156] 74 heat exchangers

[0157] 76 Low-pressure steam flow

[0158] 77 Coolant flow

[0159] 78 Electrolyzer

[0160] 80 compressors

[0161] 82 external low-pressure steam

[0162] 84 Hydrogen source

[0163] 85 Carbon oxide source

[0164] 86 Processes for the synthesis of methanol

[0165] 88, 90, 92, 94, 96, 98, 100, 102 Procedural steps

Claims

Patent claims 1. Methanol synthesis plant (24) with at least one hydrogen source (84), a carbon oxide source (85), a methanol synthesis reactor (30), a jet pump (10) and a low-pressure steam source, wherein the methanol synthesis reactor (30) is configured to catalytically convert hydrogen supplied by the hydrogen source (84) and carbon oxide supplied by the carbon oxide source (85) at least partially to methanol (50) and to provide at least a proportionate amount as a reactor product stream (32), characterized in that the jet pump (10) receives at a first inlet at least a motive steam stream (18) based on at least a coolant stream (58) of the methanol synthesis reactor (30), wherein the coolant stream (58) is at least partially liquid and / or gaseous, wherein the jet pump (10) receives at a second inlet at least a suction steam stream (20) based on a low-pressure steam stream (76) provided by the low-pressure steam source,wherein the suction steam flow (20) has a lower pressure than the motive steam flow (18), wherein the jet pump (10) is configured to provide a mixed steam flow (22) based on the motive steam flow (18) and the suction steam flow (20), which has a higher pressure than the suction steam flow (20) and which can be used as an energy source.

2. Methanol synthesis plant (24) according to claim 1, characterized in that a pressure and / or a temperature of the mixed steam flow (22) provided by the at least one jet pump (10) is adjustable based on a variation of at least one pressure or temperature of the motive steam flow (18) and / or the suction steam flow (20) and / or a quantity ratio of the motive steam flow (18) to the suction steam flow (20).

3. Methanol synthesis plant (24) according to claim 1 or 2, characterized in that the coolant flow (58) can be supplied to a steam drum (66) on the outlet side of the methanol synthesis reactor (30). is, wherein the steam drum (66) is arranged to separate a gaseous motive steam stream (18) from the coolant stream (58).

4. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the methanol synthesis plant (24) has at least several methanol synthesis reactors (30), and wherein each methanol synthesis reactor (30) is configured to provide a coolant flow (58) which can be supplied at least partially as a motive steam flow (18) to the at least one jet pump (10).

5. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the methanol synthesis plant (24) has several jet pumps (10), each jet pump (10) being configured to obtain at least one motive steam stream (18) at a first inlet based on at least one coolant stream (58) of a methanol synthesis reactor (30), to obtain at least one suction steam stream (20) at a second inlet based on at least one low-pressure steam stream (76) provided by at least one low-pressure steam source, and to provide a mixed steam stream (22) based on the respective motive steam stream (18) and the respective suction steam stream (20), and wherein the methanol synthesis plant (24) is configured such that the pressures and / or temperatures of the mixed steam streams (22) provided separately by the several jet pumps (10) are the same or differ from each other.

6. Methanol synthesis plant (24) according to claim 5, characterized in that the several suction steam streams (20) are fluidically coupled to each other by a suction steam rail (21) or can be supplied separately to different jet pumps (10).

7. Methanol synthesis plant (24) according to claim 5 or 6, characterized in that the several motive steam streams (18) are fluidically coupled to each other by a motive steam rail (19) or can be supplied separately to different jet pumps (10).

8. Methanol synthesis plant (24) according to one of claims 3 to 7, insofar as related back to claim 3, characterized in that at least one heating element (64) is coupled to the steam drum (66) and a methanol synthesis reactor (30) and is configured to increase an amount of the motive steam flow (18) provided for a jet pump (10).

9. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the methanol synthesis plant (24) has at least one heat exchanger (74) as part of the low-pressure steam source, which is at least indirectly fluidically coupled to the methanol synthesis reactor (30), and which is arranged to provide a low-pressure steam flow (76) as a suction steam flow (20) at an inlet of at least one jet pump (10), in particular wherein the low-pressure steam flow (76) is based on a coolant flow (77).

10. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the low-pressure steam source is configured to ensure an externally provided steam (82) as a low-pressure steam stream (76) for the methanol synthesis plant (24) as a suction steam stream (20) at an inlet of at least one jet pump (10).

11. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the motive steam flow (18) at the inlet of the jet pump (10) has a pressure in the range of 10 to 45 bar absolute and a temperature in the range of 200°C to 280°C, preferably a pressure in the range of 25 to 42 bar absolute and a temperature in the range of 230°C to 250°C, further preferably a pressure in the range of 29 up to 40 bar absolute and a temperature in the range of 230°C to 250°C, the suction steam flow (20) at the inlet of the jet pump (10) has a pressure in the range of 2 to 6 bar absolute and a temperature in the range of 120°C to 250°C, preferably a pressure in the range of 2.7 to 4.5 bar absolute and a temperature in the range of 140°C to 210°C, and the mixed steam flow (22) at the outlet of the jet pump (10) has a pressure in the range of 4 to 12 bar absolute and a temperature in the range of 130°C to 200°C, preferably a pressure in the range of 5.5 to 9 bar absolute and a temperature in the range of 155°C to 175°C.

12. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the mixture ratio of the motive steam stream (18) to the suction steam stream (20) in the jet pump (10) is in the range of 0.5 to 9, preferably from 1 to 6.

13. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the hydrogen source (84) has an electrolyzer (78) which is configured to produce hydrogen, in particular wherein the electrolyzer (78) can be operated with electrical energy obtained from renewable energies.

14. Methanol synthesis plant (24), according to one of the preceding claims, characterized in that the methanol synthesis reactor (30) is a boiling water-cooled tube bundle reactor.

15. Methanol synthesis plant (24) according to one of the preceding claims, characterized in that the coolant (60) comprises water.

16. Process (86) for the synthesis of methanol (50), wherein the process (86) at least includes the following steps: Providing hydrogen by a hydrogen source (84), - Provision of carbon oxide by a carbon oxide source (85), - Providing a reactor product stream (32) of a methanol synthesis reactor (30), wherein the reactor product stream (32) comprises at least a proportion of methanol (50) catalytically reacted from hydrogen and carbon oxide, wherein the process (86) is characterized in that it further comprises: - Receiving a motive steam stream (18) at a first inlet of a jet pump (10) based on at least a coolant stream (58) of the methanol synthesis reactor (30), wherein the coolant stream (58) is at least partially liquid and / or gaseous, - Receiving a suction steam stream (20) at a second Inlet of a jet pump (10) based at least on a low-pressure steam source Low-pressure steam flow (76), wherein the suction steam flow (20) has a lower pressure than the motive steam flow (18), - Providing a mixed steam stream (22) through the jet pump (10) based on the motive steam stream (18) and the suction steam stream (20), wherein the mixed steam stream (22) has a higher pressure than the suction steam stream (20), and - Use of the mixed steam flow (22) as an energy source.

17. Method (86) according to claim 16, characterized in that a The pressure and / or temperature of the mixed steam flow (22) provided by the at least one jet pump (10) is variable based on a variation of at least one pressure and / or temperature of the motive steam flow (18) and / or the suction steam flow (20) and / or a quantity ratio of the motive steam flow (18) to the suction steam flow (20).

18. Method (86) according to claim 16 or 17, characterized in that different coolant streams (58) are provided based on at least several methanol synthesis reactors (30), which are supplied at least partially as motive steam streams (18) to at least one jet pump (10).

19. Method (86) according to one of claims 16 to 18, characterized in that several jet pumps (10) are provided which supply respective mixed steam streams (22), and wherein the pressures and / or temperatures of the mixed steam streams (22) provided separately by the several jet pumps (10) are the same or differ from each other.

20. Method (86) according to one of claims 16 to 19, characterized in that an amount of the motive steam flow (18) provided for a jet pump (10) is increased based on at least one heating element (64).

21. Method (86) according to one of claims 16 to 20, characterized in that at least one low-pressure steam flow (76) from a heat exchanger (74) of the low-pressure steam source is provided as a suction steam flow (20) at an inlet of at least one jet pump (10), in particular wherein the low-pressure steam flow (76) is based on a coolant flow (77).

22. Method (86) according to one of claims 16 to 21, characterized in that an externally supplied steam (82) in the form of the low-pressure steam flow (76) is supplied as a suction steam flow (20) at an inlet of at least one jet pump (10).

23. Method (86) according to one of claims 16 to 22, characterized in that the hydrogen is produced based on an electrolyzer (78), in particular wherein the electrolyzer (78) is operated with electrical energy obtained from renewable energies.

24. Method (86) according to one of claims 16 to 23, characterized in that methanol (50) is at least partially separated from the reactor product stream (32) in a distillation section (44) and the mixed steam stream (22) is used as an energy source in the distillation section (44).

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