Apparatus and method for producing methanol
By converting carbon monoxide and water in syngas into hydrogen in a non-catalytic partial oxidation (POX) process, combined with a single-cycle compressor and a shared steam package, the problem of insufficient hydrogen in syngas was solved, achieving low-cost and high-efficiency methanol production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
- Filing Date
- 2022-02-24
- Publication Date
- 2026-06-12
AI Technical Summary
In existing technologies for producing methanol via non-catalytic partial oxidation (POX) processes, insufficient hydrogen content in the syngas leads to inappropriate stoichiometry, increasing investment and production costs, which is particularly disadvantageous for smaller plants.
Syngas is produced using a partial oxidation (POX) process, and carbon monoxide and water are converted into hydrogen and carbon dioxide in a water-gas shift reactor. Combined with a single-cycle compressor and a shared steam package, the equipment configuration is simplified and the investment cost is reduced.
It increases the hydrogen content of syngas, meets stoichiometric requirements, reduces the number of equipment, and lowers production costs, making it particularly suitable for smaller plants and modular plants.
Smart Images
Figure CN115073267B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates generally to methanol production; more specifically, it relates to equipment and methods for producing methanol from syngas generated by non-catalytic partial oxidation (POX). Background Technology
[0002] The most common process for producing methanol from a hydrocarbon stream is catalytic steam reforming. Catalytic steam reforming can employ up to three catalytic steps, including a pre-reforming step, a first-stage reforming step, and a second-stage reforming step; these steps are used in larger plants to produce optimal syngas for methanol production. The standard practice for producing syngas in larger plants is to use a combined reforming method. In a combined reforming method, the first portion of the hydrocarbon stream is treated in a steam methane reformer (SMR), and the SMR effluent, along with the second portion of the hydrocarbon stream, is treated in an autothermal reformer (ATR). In this case, the SMR is the first-stage reformer, and the ATR is the second-stage reformer. For smaller plants, SMR is used alone to produce syngas. However, syngas produced solely by SMR is stoichiometrically excess syngas containing too much hydrogen.
[0003] A less common method for producing syngas is the non-catalytic partial oxidation (POX) process. Unfortunately, the POX process produces an unsuitable, substoichiometric syngas lacking hydrogen. Therefore, measures are needed to increase the amount of hydrogen in the syngas entering the methanol synthesis loop.
[0004] Regarding methanol synthesis, the stoichiometric coefficient (SN) can be defined as follows to characterize the gas composition leading to methanol synthesis:
[0005] SN = {H2-CO2} / {CO+CO2}
[0006] Where H2, CO, and CO2 are the mole fractions or mole percentages in the gaseous composition. The required SN for methanol production is 2.0. As described in the preceding paragraphs, SMR produces syngas with an SN greater than about 3. Combined reforming can produce an SN of exactly 2.0, and POX produces an SN < 2. The exact SN value for each reforming process depends on the feedstock composition and the design and selection of operating conditions.
[0007] Some existing methods feed a portion of the substoichiometric syngas to a hydrogen recovery unit or a membrane unit for hydrogen recovery and reuse to adjust the hydrogen content of the syngas. However, these methods can result in significant tail gas emissions and poor carbon efficiency in methanol production. Furthermore, for ATR-only designs at very large production scales (i.e., methanol production exceeding approximately 7,500 metric tons per day (mtpd), the practice of feeding substoichiometric syngas to a hydrogen recovery unit or membrane unit is conventionally considered because, in SMR-only or combined reforming configurations used for syngas production at this scale, the SMR cannot be very large and is therefore uneconomical.
[0008] Other existing methods increase the amount of hydrogen by reducing the recycle ratio in the methanol synthesis loop. This generates a larger purge gas stream from which hydrogen is recovered and recycled back to the makeup gas. However, this results in low carbon efficiency and an increased demand for fresh syngas used in the synthesis.
[0009] Other known methods combine a certain amount of hydrogen feedstock with syngas to adjust the stoichiometric balance used for methanol synthesis. However, this requires a suitable hydrogen source of appropriate scale, which can be economically disadvantageous. For example, hydrogen produced by electrolysis can be used for this purpose; however, its production remains relatively expensive and is not always available on-site at methanol production plants. Alternatively, at the location of a methanol production plant, an input hydrogen supply from any external source may indeed be unavailable.
[0010] Typically, methanol production processes utilize a combination of different catalytic reforming steps to avoid hydrogen deficiency in the syngas. However, catalytic reforming requires significant capital expenditure, which is particularly disadvantageous for smaller plants where capital and engineering costs have a greater impact on methanol production costs. A secondary key issue for smaller plants is that each equipment item contributes considerably to both total investment and production costs due to the required engineering work.
[0011] Another common practice is to use a water-gas shift reactor to convert carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2). In conventional equipment, using a water-gas shift reactor necessitates additional steps to separate CO2 from syngas, such as pressure swing absorption (PSA), membrane filtration, amine washing, and physical absorption, to increase the SN of the syngas.
[0012] While several methods exist to compensate for hydrogen shortages, they result in high investment costs, especially for smaller plants. Such increased investment costs are often unaffordable.
[0013] Therefore, it is necessary to address the aforementioned technical shortcomings of existing technologies for producing methanol from substoichiometric syngas. Summary of the Invention
[0014] This disclosure seeks to provide an improved method for producing methanol from syngas generated by non-catalytic partial oxidation (POX) with simplified equipment, low investment costs, and low production costs. The object of this disclosure is to provide solutions to at least some of the problems encountered in the prior art, and to provide improved methods and equipment for producing methanol from syngas generated by non-catalytic partial oxidation (POX) without the use of complex multi-tube steam reformers. The objectives of this disclosure are achieved by the embodiments defined in the appended independent claims. Advantageous embodiments of this disclosure are further defined in the dependent claims.
[0015] According to a first aspect, a method for producing methanol from syngas is provided, characterized in that the method comprises:
[0016] - In the partial oxidation (POX) chamber, a synthesis gas with a stoichiometric number of less than approximately 1.8 is produced by a partial oxidation (POX) process using a hydrocarbon stream and an oxygen stream;
[0017] - In a water-gas shift reactor, the syngas is passed over a water-gas shift catalyst to convert at least a portion of the carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining shifted syngas;
[0018] -Dry shifted syngas is produced by separating liquid condensate from the shifted syngas;
[0019] - In a recycle compressor, the dried, shifted syngas is combined with a recycle syngas containing unreacted syngas and hydrogen-rich products to form a mixed syngas stream; and
[0020] - In a cooled methanol synthesis reactor, at least a portion of the mixed synthesis gas stream is converted into methanol.
[0021] The advantage of this improved method for methanol production lies in its use of partial oxidation (POX) as the sole source of syngas production. Furthermore, the method utilizes a single-cycle compressor and a shared steam package within the methanol synthesis loop to collect steam generated by water cooling of the water-gas shift reactor and the cooled methanol synthesis reactor, significantly reducing the number of machines and thus lowering investment costs. Additionally, the reaction heat from the water-gas shift reactor and the cooled methanol synthesis reactor can be used for steam production, further reducing production costs. Therefore, the improved method disclosed herein is particularly advantageous for smaller or modular plants that still provide a suitable syngas mixture for methanol production.
[0022] This method increases the hydrogen (H2) content during the water-gas shift reaction by converting a portion of the carbon monoxide (CO) and water (H2O) in the syngas into hydrogen (H2) and carbon dioxide (CO2), thereby generating a favorable stoichiometry and preventing hot spots that might otherwise occur in the cooled methanol synthesis reactor at high carbon monoxide (CO) contents.
[0023] According to a second aspect, an apparatus for producing methanol from syngas is provided, characterized in that the apparatus comprises a series of:
[0024] - Partial oxidation (POX) chamber, used to produce syngas with a stoichiometric number of less than approximately 1.8 by using a partial oxidation (POX) process with a hydrocarbon stream and an oxygen stream;
[0025] - A water-gas shift reactor is used to pass the syngas through a water-gas shift catalyst to convert at least a portion of carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining shifted syngas;
[0026] - A condensate separator is used to separate liquid condensate from the shifted syngas to produce dry shifted syngas;
[0027] - A recycle compressor for combining the dried, shifted syngas with a recycle syngas containing unreacted syngas and hydrogen-rich products to form a mixed syngas stream; and
[0028] - A cooled methanol synthesis reactor for converting at least a portion of the mixed synthesis gas stream into methanol.
[0029] The advantage of this methanol production equipment is that it uses a partial oxidation (POX) process as the sole source of syngas production. Furthermore, the equipment includes a single-cycle compressor within the methanol synthesis loop and a shared steam package to collect steam generated by water cooling the water-gas shift reactor and the cooled methanol synthesis reactor by boiling water. This significantly reduces the number of required machines, thereby lowering investment costs. Additionally, the heat of reaction from the water-gas shift reactor and the cooled methanol synthesis reactor can be used for steam production, further reducing production costs. Therefore, the equipment disclosed herein is particularly advantageous for smaller or modular plants that still provide a suitable syngas mixture for methanol production.
[0030] This water-gas shift reactor increases the hydrogen (H2) content by converting a portion of the carbon monoxide (CO) and water (H2O) in the syngas into hydrogen (H2) and carbon dioxide (CO2) during the water-gas shift reaction, thereby producing a favorable stoichiometry and preventing hot spots that might otherwise occur in the cooled methanol synthesis reactor at high carbon monoxide content.
[0031] The embodiments disclosed herein eliminate the aforementioned drawbacks in existing known methods for producing methanol from syngas produced from non-catalytic partial oxidation (POX). An advantage of the embodiments disclosed herein is that they enable the combination of a water-gas shift reactor downstream of the partial oxidation (POX) chamber and upstream of the cooled methanol synthesis reactor with hydrogen purification of purge gas from lower cycle ratio operations to adjust the stoichiometry and hydrogen content of the syngas used for methanol production. The embodiments of the invention are cost-effective because they do not require complex equipment configurations and do not necessitate additional steps to compensate for the substoichiometric hydrogen deficiency in the syngas.
[0032] Further aspects, advantages, features, and objectives of this disclosure will become apparent from the accompanying drawings and detailed description of exemplary embodiments, which are interpreted in conjunction with the appended claims.
[0033] It should be recognized that the features of this disclosure can be combined in various combinations without departing from the scope of this disclosure as defined by the appended claims. Attached Figure Description
[0034] The above-described invention and the following detailed description of exemplary embodiments will be better understood when read in conjunction with the accompanying drawings. For illustrative purposes, exemplary constructions of this disclosure are shown in the drawings. However, this disclosure is not limited to the specific methods and means disclosed herein. Furthermore, those skilled in the art will understand that the drawings are not drawn to scale. Where possible, the same elements are represented by the same numbers.
[0035] The embodiments disclosed herein will now be described by way of example only, with reference to the following figures:
[0036] Figure 1 This is a schematic diagram of a first embodiment of an apparatus for producing methanol from syngas according to the embodiments of this disclosure;
[0037] Figure 2 This is a schematic diagram of a second embodiment of an apparatus for producing methanol from syngas according to the embodiments of this disclosure; and
[0038] Figure 3A and 3BThis is a flowchart illustrating the steps of a method for producing methanol from syngas according to embodiments of this disclosure.
[0039] In the accompanying drawings, underlined numbers indicate items located above or adjacent to the underlined number. Ununderlined numbers refer to items identified by a line connecting the ununderlined number to the item. When a number is ununderlined and accompanied by an associated arrow, the ununderlined number identifies the general item to which the arrow points. Detailed Implementation
[0040] The following detailed description illustrates embodiments of this disclosure and ways in which it can be implemented. Although some models for carrying out this disclosure have been disclosed, those skilled in the art will recognize that other embodiments for carrying out or practicing this disclosure are also possible.
[0041] According to a first aspect, a method for producing methanol from syngas is provided, characterized in that the method comprises:
[0042] - In the partial oxidation (POX) chamber, a synthesis gas with a stoichiometric number of less than approximately 1.8 is produced by a partial oxidation (POX) process using a hydrocarbon stream and an oxygen stream;
[0043] - In a water-gas shift reactor, the syngas is passed over a water-gas shift catalyst to convert at least a portion of the carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining shifted syngas;
[0044] -Dry shifted syngas is produced by separating liquid condensate from the shifted syngas;
[0045] - In a recycle compressor, the dried, shifted syngas is combined with a recycle syngas containing unreacted syngas and hydrogen-rich products to form a mixed syngas stream; and
[0046] - In a cooled methanol synthesis reactor, at least a portion of the mixed synthesis gas stream is converted into methanol.
[0047] The advantage of this method for methanol production lies in its use of partial oxidation (POX) as the sole source of syngas production. Furthermore, the method utilizes a single-cycle compressor and a shared steam package within the methanol synthesis loop to collect steam generated by water cooling of the water-gas shift reactor and the cooled methanol synthesis reactor, significantly reducing the number of machines and thus lowering investment costs. Additionally, the reaction heat from the water-gas shift reactor and the cooled methanol synthesis reactor can be used for steam production, further reducing production costs. Therefore, the method disclosed herein is particularly advantageous for smaller or modular plants that still provide a suitable syngas mixture for methanol production.
[0048] According to an embodiment, the hydrocarbon stream is natural gas, coal gas, methane hydrate, and / or contains hydrocarbons such as naphtha or other hydrocarbons that are liquid under environmental conditions, such as refinery residues, cracking furnace residues, or the like.
[0049] The partial oxidation (POX) process is a non-catalytic exothermic reaction in which the hydrocarbon stream and the oxygen stream react to produce the syngas. The partial oxidation (POX) process can be carried out in the presence of steam and / or carbon dioxide as a moderator.
[0050] Optionally, the method includes cooling the syngas to a first temperature without water vapor condensation before passing it over the water-gas shift catalyst, thereby simplifying equipment configuration for methanol production and reducing investment costs. The first temperature can be in the range of 200°C to 300°C.
[0051] According to an embodiment, the water-gas shift catalyst includes a low-temperature water-gas shift catalyst, a high-temperature water-gas shift catalyst, or an isothermal and medium-temperature water-gas shift catalyst (e.g., operating in a temperature range of 220°C to 320°C).
[0052] According to an embodiment, the heat of reaction in the water-gas shift reactor is managed by circulating water (natural water or pumped water) to generate steam.
[0053] Optionally, in this method, generating the dried, shifted synthesis gas includes:
[0054] - In the first cooling unit, the converted synthesis gas is cooled to a condensation point at a second temperature (e.g., in the range of 50°C to 150°C) to form the liquid condensate; and
[0055] - In a condensate separator, the liquid condensate is separated from the shifted syngas to produce the dry shifted syngas.
[0056] Optionally, the method includes:
[0057] - In the second cooling unit, the effluent from the methanol synthesis reactor is cooled to a condensation point at a third temperature (e.g., typically in the range of 40°C to 60°C) to produce a condensate containing crude methanol and water; and
[0058] - In a methanol separator, the crude methanol is separated from the unreacted syngas.
[0059] The method also includes:
[0060] - The first portion of the unreacted syngas from the methanol separator is sent as the recycled syngas to the recycled compressor;
[0061] - A second portion of the unreacted syngas from the methanol separator is sent to a hydrogen recovery unit, such as a PSA; and
[0062] - In the hydrogen recovery unit, the hydrogen-rich product is generated, which is then mixed with the circulating synthesis gas stream before entering the circulating compressor to form the mixed synthesis gas stream.
[0063] The hydrogen recovery unit can be a pressure swing absorption (PSA) hydrogen recovery unit.
[0064] According to an embodiment, the method includes reducing the recycle ratio in the methanol synthesis loop, thereby generating a purge gas stream from which hydrogen content is recovered and recycled back to the mixed synthesis gas stream.
[0065] Optionally, the method includes compressing the mixed synthesis gas flow in the cyclic compressor by increasing the pressure of the mixed synthesis gas flow.
[0066] Optionally, the method includes
[0067] - Mix the hydrocarbon stream and the oxygen stream with steam at a maximum of about 30% by volume in each stream; and / or
[0068] - The hydrocarbon stream and the oxygen stream are preheated and then supplied to the partial oxidation (POX) chamber for the partial oxidation (POX) process.
[0069] Optionally, in this method, (i) the converted synthesis gas is cooled to the condensation point and the liquid condensate is separated from the converted synthesis gas, and (ii) the methanol synthesis reaction effluent is cooled to the condensation point and the crude methanol is separated from the unreacted synthesis gas, in an apparatus shared by (i) and (ii).
[0070] Optionally, the method includes arranging the water-gas shift reactor and the cooled methanol synthesis reactor to share a common coolant and steam generation system, for example, a common steam generation system in the case where both reactors are cooled by boiling water. This method advantageously reduces the large amount of equipment required for methanol production, thereby lowering investment costs.
[0071] Optionally, the method includes housing the water-gas shift reactor and the cooled methanol synthesis reactor in the same container. This method advantageously reduces the large amount of equipment required for methanol production, thereby lowering investment costs.
[0072] Optionally, the method includes operating the partial oxidation (POX) chamber and the water-gas shift reactor under pressure conditions in the range of 30 bar to 90 bar.
[0073] According to an embodiment, the partial oxidation (POX) process is carried out under a nominal pressure greater than about 30 bar. The partial oxidation (POX) process can advantageously be carried out under pressure exceeding about 60 bar. The partial oxidation (POX) process can most advantageously be carried out under pressure conditions between 60 bar and 90 bar.
[0074] According to an embodiment, the syngas shift (i.e., conversion) is carried out at a nominal pressure greater than about 30 bar. The syngas shift can advantageously be carried out at a pressure exceeding about 60 bar. Most advantageously, the syngas shift can be carried out at a pressure between 60 and 90 bar.
[0075] According to a second aspect, an apparatus for producing methanol from syngas is provided, characterized in that the apparatus comprises a series of:
[0076] - Partial oxidation (POX) chamber for producing syngas with a stoichiometric number of less than approximately 1.8 (e.g., 1.83) by a partial oxidation (POX) process using a preferably preheated hydrocarbon stream and a preferably preheated oxygen stream;
[0077] - A water-gas shift reactor is used to pass the syngas through a water-gas shift catalyst (i.e., shift) to convert at least a portion of carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining shifted syngas;
[0078] - A condensate separator is used to separate liquid condensate from shifted syngas to produce dry shifted syngas;
[0079] - A recycle compressor for combining the dried, shifted syngas with a recycle syngas containing unreacted syngas and hydrogen-rich products to form a mixed syngas stream; and
[0080] - A cooled methanol synthesis reactor for converting at least a portion of the mixed synthesis gas stream into methanol.
[0081] The advantage of this methanol production equipment is that it uses a partial oxidation (POX) process as the sole source of syngas production. Furthermore, the equipment includes a single-cycle compressor within the methanol synthesis loop and a shared steam package to collect steam generated by cooling the water-gas shift reactor and the cooled methanol synthesis reactor by boiling water. This significantly reduces the number of required machines, thereby lowering investment costs. Additionally, the reaction heat from the water-gas shift reactor and the cooled methanol synthesis reactor can be used for steam production, further reducing production costs. Therefore, the equipment disclosed herein is particularly advantageous for smaller or modular plants that still provide a suitable syngas mixture for methanol production.
[0082] According to an embodiment, the hydrocarbon stream is natural gas, coal gas, or methane hydrate, and / or contains hydrocarbons such as naphtha or other hydrocarbons that are liquid under environmental conditions, such as refinery residues, cracking furnace residues, or the like.
[0083] The partial oxidation (POX) process is a non-catalytic exothermic reaction in which the hydrocarbon stream and the oxygen stream react to produce the syngas. The partial oxidation (POX) process can be carried out in the presence of steam and / or carbon dioxide as a moderating agent.
[0084] Before passing the syngas over the water-gas shift catalyst, a cooling device (such as a waste heat boiler) can be used to cool the syngas to a first temperature without causing water vapor condensation. This first temperature can be in the range of 200°C to 300°C.
[0085] This equipment advantageously delivers syngas from the partial oxidation (POX) chamber to the water-gas shift reactor without cooling it below the dew point and subsequently cooling it in the water-gas shift reactor, thereby simplifying equipment configuration for methanol production and reducing its investment costs.
[0086] According to an embodiment, the water-gas shift catalyst includes a low-temperature water-gas shift catalyst, a high-temperature water-gas shift catalyst, and an isothermal and medium-temperature water-gas shift catalyst (e.g., operating in the range of 220°C to 320°C).
[0087] According to an embodiment, the heat of reaction in the water-gas shift reactor is managed by circulating water (natural water or pumped water) to generate steam.
[0088] Optionally, the device includes:
[0089] - A first cooling unit is used to cool the converted synthesis gas to a condensation point at a second temperature (e.g., in the range of 50°C to 150°C) to form the liquid condensate.
[0090] Optionally, the device includes:
[0091] - A second cooling unit is used to cool the effluent from the methanol synthesis reactor to a condensation point at a third temperature (e.g., typically in the range of 40°C to 60°C) to produce a condensate containing crude methanol and water; and
[0092] - A methanol separator is used to separate the crude methanol from the unreacted syngas.
[0093] In this device, the methanol separator is configured to send a first portion of the unreacted syngas as recycled syngas to the recycled compressor.
[0094] The device includes
[0095] A hydrogen recovery unit, such as a pressure swing absorption (PSA), is used to (i) receive a second portion of unreacted syngas from the methanol separator, and (ii) generate a hydrogen-rich product which is to be mixed with a circulating syngas stream before entering a circulating compressor to form a mixed syngas stream.
[0096] According to an embodiment, the device reduces the recycle ratio in the methanol synthesis loop and thereby generates a purge gas stream from which hydrogen content is recovered and recycled back to the mixed synthesis gas stream.
[0097] Optionally, the equipment is configured to mix both the hydrocarbon stream and the oxygen stream with steam, and / or preheat the hydrocarbon stream and the oxygen stream before supplying them to the partial oxidation (POX) chamber for the partial oxidation (POX) process.
[0098] Optionally, in this device, the circulating compressor is configured to compress the mixed synthetic gas stream by increasing the pressure of the mixed synthetic gas stream.
[0099] Optionally, the device includes:
[0100] - A steam package is used to provide steam generated by cooling the water-gas shift reactor and the cooled methanol synthesis reactor by boiling water.
[0101] Optionally, in this equipment, the water-gas shift reactor and the cooled methanol synthesis reactor share a common coolant and steam generation system, thereby reducing the investment costs involved.
[0102] Optionally, in this apparatus, the water-gas shift reactor and the cooled methanol synthesis reactor are housed together in the same container.
[0103] Optionally, in this apparatus, the partial oxidation (POX) chamber and the water-gas shift reactor are configured to operate under pressure conditions in the range of 30 bar to 90 bar.
[0104] According to an embodiment, the partial oxidation (POX) process is carried out under a nominal pressure greater than about 30 bar. The partial oxidation (POX) process can advantageously be carried out under pressure exceeding about 60 bar. Most advantageously, the partial oxidation (POX) process can be carried out under pressure conditions between 60 bar and 90 bar.
[0105] According to an embodiment, the syngas shift (i.e., conversion) is carried out at a nominal pressure greater than about 30 bar. The syngas shift can advantageously be carried out at a pressure exceeding about 60 bar. Most advantageously, the syngas shift can be carried out at a pressure between 60 and 90 bar.
[0106] Detailed description of the attached figures
[0107] Modifications may be made to embodiments of the disclosure described above without departing from the scope of the disclosure as defined by the appended claims. Expressions such as “comprising,” “including,” “incorporated,” “having,” and “is” used to describe and claim this disclosure are intended to be interpreted in a non-exclusive manner, allowing for the presence of items, components, or elements not explicitly described. Singular references are also interpreted to refer to the plural.
[0108] Figure 1 This is a schematic diagram of a first embodiment of an apparatus 100 for producing methanol from syngas according to embodiments of this disclosure. Apparatus 100 includes a partial oxidation (POX) chamber 102, a circulating compressor 104, a heating unit 106, a water-gas shift / methanol reactor 108, a cooling unit 110A, a vapor-liquid separator 112, a hydrogen recovery unit 114, and a steam package 116. Apparatus 100 also includes a second cooling unit 110B. The partial oxidation (POX) chamber 102 is configured to receive a hydrocarbon stream and an oxygen stream, and to produce syngas having a stoichiometric number of less than 1.8 by performing a partial oxidation (POX) process with the hydrocarbon stream and the oxygen stream. The hydrocarbon stream and the oxygen stream are preheated to a first temperature; this first temperature is advantageously in the range of 150°C to 500°C. The hydrocarbon stream and the oxygen stream are optionally mixed with steam from the steam package 116 or other sources.
[0109] The water-gas shift / methanol reactor 108 in the first embodiment is designed to separate the reaction of the recycle syngas to methanol from the water-gas shift (WGS) reaction of the cooled POX gas. A second cooling unit 110B is connected downstream of the partial oxidation (POX) chamber 102 and is configured to cool the effluent of the partial oxidation (POX) process to form cooled syngas. The shift section of the water-gas shift / methanol reactor 108 is configured to receive the cooled syngas from the second cooling unit 110B using contained steam. The shift section of the water-gas shift / methanol reactor 108 can convert at least a portion of the carbon monoxide (CO) and water (H2O) in the syngas into hydrogen (H2) and carbon dioxide (CO2). The methanol synthesis section of the water-gas shift / methanol reactor 108 is configured to receive heated, dried, and unreacted recycle syngas from the recycle gas compressor 104 and the heating unit 106. The methanol synthesis section of the water-gas shift / methanol reactor 108 can convert at least a portion of carbon monoxide (CO) and hydrogen (H2) into methanol.
[0110] The water-gas shift / methanol reactor 108 can be a cooled reactor and preferably operates in a pressure range of 60 to 90 bar. The heat of reaction in the water-gas shift / methanol reactor 108 is managed by circulating water (naturally circulating water or pumped water) to generate steam. The steam or water vapor is separated from the circulating water in a steam package 116. After separating the steam from the circulating water, the water can be reused to generate additional steam.
[0111] As shown, cooling unit 110A is configured to cool the effluent from reactor 108; optionally, it can be configured to receive two separate effluents from water-gas shift / methanol reactor 108 (i.e., from the shift section and methanol synthesis section of water-gas shift / methanol reactor 108) and form a combined condensate by cooling these effluents to a second temperature, or form two separate condensates (i.e., a first condensate and a second condensate) by cooling these effluents to a second temperature; the second temperature is advantageously in the range of 40°C to 80°C. The second temperature can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C. Cooling can be achieved by exchanging with a cold process stream, or with a cooling facility, or a combination thereof. The cooling facility can include air or cooling water. A first portion of the cooling of the effluent can be carried out by heat exchange with the feed to water-gas shift / methanol reactor 108. A second portion of the cooling of the effluent can be carried out by using the cooling facility to form the first condensate. The vapor-liquid separator 112 is configured to receive the first condensate from the cooling unit 110A and form dry, unreacted synthesis gas as a supplementary gas for methanol production by removing the liquid condensate.
[0112] The vapor-liquid separator 112 can optionally be configured to receive two separate effluent streams from the cooling unit 110A, or to receive a single combined effluent stream from the cooling unit 110A. Downstream of the vapor-liquid separator 112, crude methanol is collected via a second flow line 120, and optionally, condensate is collected via a first flow line 118. The vapor-liquid separator 112 is configured to collect crude methanol for subsequent purification, which... Figure 1 Not shown in the diagram. Crude methanol can optionally be collected separately from or together with the condensate from the water-gas shift / methanol reactor effluent. The effluent from water-gas shift / methanol reactor 108 can remain separate up to the vapor-liquid separator 112. Baffles in methanol separator 112 can separate the water-gas shift / methanol reactor condensate.
[0113] The vapor phase from the vapor-liquid separator 112 is separated into a first part and a second part. The first part is directly recycled, and the second part is purged from the methanol synthesis loop to the hydrogen recovery unit 114. The hydrogen recovery unit 114 may be a pressure swing absorption (PSA) hydrogen recovery unit. The hydrogen recovery unit 114 produces a hydrogen-rich product, which is then recombine with the recycle gas and returned to the suction port of the recycle compressor 104. The residual gas (tail gas) from the pressure swing absorption (PSA) hydrogen recovery unit 114 is purged for use as fuel.
[0114] The circulating compressor 104 increases the pressure of the syngas to overcome the pressure drop in the methanol synthesis loop. Typical pressures exceed approximately 60 bar and reach up to approximately 90 bar, roughly corresponding to POX pressure. The temperature of the pressurized syngas mixture is increased in the heating unit 106. Typical temperatures begin to approach the methanol synthesis temperature of 220°C to 300°C. Heating can be implemented by exchanging heat with the process flow, exchanging heat with heating equipment, or a combination thereof. The heating unit 106 and the cooling unit 110A are coupled on the cold and hot sides of the process gas exchanger, respectively. The preheated syngas mixture is fed into the water-gas shift / methanol reactor 108. The heat released from the water-gas shift reaction and methanol synthesis is managed jointly in a single reactor and a single steam package 116.
[0115] Figure 2This is a schematic diagram of a second embodiment of an apparatus 200 for producing methanol from syngas according to embodiments of this disclosure. The apparatus 200 includes a series of partial oxidation (POX) chambers 202, a cooling device 224, a water-gas shift reactor 204, a first cooling unit 206, a condensate separator 208, a circulating compressor 210, a heating unit 212, a cooled methanol synthesis reactor 214, a second cooling unit 216, a methanol separator 218, a hydrogen recovery unit 220, and a steam package 222. The partial oxidation (POX) chambers 202 are configured to receive hydrocarbon streams and oxygen streams, and to produce syngas having a stoichiometric number of less than 1.8 by performing a partial oxidation (POX) process with the hydrocarbon streams and the oxygen streams. The cooling device 224 is configured to optionally cool the partial oxidation (POX) effluent, such as the syngas, without condensation. The cooling device 224 partially cools the syngas. The water-gas shift reactor 204 is configured to receive partially cooled syngas and pass it over a water-gas shift catalyst to convert at least a portion of carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining shifted syngas. The water-gas shift reactor 204 is cooled to a first temperature, typically in the range of 200°C to 300°C, by boiling water to remove the heat of reaction. A first cooling unit 206 is configured to receive the shifted syngas and cool it to a condensation point at a second temperature, typically 40°C to 80°C, to form a liquid condensate. Cooling can be implemented by exchanging with a cold process stream, with a cooling facility, or a combination thereof. A condensate separator 208 is configured to receive the cooled shifted syngas and produce dry shifted syngas (not shown) by separating the liquid condensate from the cooled shifted syngas. The recirculating compressor 210 is configured to receive a mixed syngas, which is a combination of dried, converted syngas and recirculating syngas containing unreacted syngas and hydrogen-rich products. The recirculating compressor 210 can increase the pressure of the syngas to overcome the pressure drop in the methanol synthesis loop. The heating unit 212 is configured to receive the mixed syngas stream and heat it to the methanol conversion temperature in the range of 200°C to 300°C. Heating can be implemented by exchanging heat with a hot process stream, or with a heating facility, or a combination thereof.
[0116] A cooled methanol synthesis reactor 214 is configured to receive a preheated, mixed synthesis gas stream and convert at least a portion of the mixed synthesis gas stream into methanol. A second cooling unit 216 is configured to receive the effluent from the cooled methanol synthesis reactor 214 and cool the effluent to a condensation point typically between 40°C and 80°C to produce a condensate containing crude methanol and water. A first portion of the effluent cooling can be achieved through heat exchange with the feed to the cooled methanol synthesis reactor 214. A second portion of the effluent cooling can be achieved using cooling facilities to form a condensate containing crude methanol and water. The heating unit 212 and the second cooling unit 216 are the cold and hot sides of the process gas exchanger, respectively. A methanol separator 218 is configured to receive the gas-liquid mixture from the second cooling unit 216 and separate the crude methanol from the unreacted synthesis gas. A first portion of the unreacted synthesis gas is directly supplied as recirculated synthesis gas to the recirculating compressor 210. A second portion of the unreacted syngas from methanol separator 218 is fed into hydrogen recovery unit 220 for producing a hydrogen-rich product, which is then mixed with the recirculating syngas stream before entering recirculating compressor 210 to form a mixed syngas stream. Hydrogen recovery unit 220 may be a pressure swing absorption (PSA) hydrogen recovery unit.
[0117] The heat of reaction in the water-gas shift reactor 204 and the cooled methanol synthesis reactor 214 is managed by circulating water (naturally circulating water or pumped water) to generate steam. The steam in the circulating water is separated in a steam package 222. After the steam is separated, the water can be reused.
[0118] Figure 3A and 3B This is a flowchart illustrating the steps of a method for producing methanol from syngas according to an embodiment of this disclosure. In step 302, syngas with a stoichiometric number of less than 1.8 is produced in a partial oxidation (POX) chamber by a partial oxidation (POX) process using a hydrocarbon stream and an oxygen stream. In step 304, the syngas is passed over a water-gas shift catalyst to convert at least a portion of carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining shifted syngas. In step 306, dried shifted syngas is produced by separating liquid condensate from the shifted syngas. In step 308, the dried shifted syngas is combined with a recycled syngas containing unreacted syngas and hydrogen-rich products to form a mixed syngas stream. In step 310, at least a portion of the mixed syngas stream is converted into methanol in a cooled methanol synthesis reactor.
[0119] Modifications may be made to embodiments of the disclosure described above without departing from the scope of the disclosure as defined by the appended claims. Expressions such as “comprising,” “including,” “incorporated,” “having,” and “is” used to describe and claim this disclosure are intended to be interpreted in a non-exclusive manner, allowing for the presence of items, components, or elements not explicitly described. Singular references are also interpreted to refer to the plural.
[0120] List of reference numerals
[0121] 100, 200 equipment
[0122] 102, 202 Partial Oxidation (POX) Chamber
[0123] 104, 210 Circulating Compressor
[0124] 106, 212 heating units
[0125] 108 Water-Gas Shift / Methanol Reactor
[0126] 110A, 110B Cooling Units
[0127] 112 Steam-Liquid Separator
[0128] 114, 220 Hydrogen Recovery Unit
[0129] 116, 222 Steam Packets
[0130] 118 First Streamline
[0131] 120 Second Streamline
[0132] 224 Cooling device
[0133] 204 Water-Gas Shift Reactor
[0134] 206 First Cooling Unit
[0135] 208 Condensate Separator
[0136] 214 Cooled methanol synthesis reactor
[0137] 216 Second Cooling Unit
[0138] 218 Methanol Separator
Claims
1. A method for producing methanol from syngas, characterized in that, The method includes: In the non-catalytic partial oxidation (POX) chambers (102, 202), a synthesis gas with a stoichiometric number of less than 1.8 is produced by a non-catalytic partial oxidation (POX) process using a hydrocarbon stream and an oxygen stream. In the water-gas shift reactor (204), the syngas is passed over a water-gas shift catalyst to convert at least a portion of the carbon monoxide (CO) and water (H2O) into hydrogen (H2) and carbon dioxide (CO2), thereby obtaining the shifted syngas; Dry shifted syngas is produced by separating the liquid condensate from the shifted syngas. In the recycle compressor (104, 210), the dried, shifted syngas is combined with a recycle syngas containing unreacted syngas and hydrogen-rich products to form a mixed syngas stream; and In a cooled methanol synthesis reactor (214), at least a portion of the mixed synthesis gas stream is converted into methanol.
2. The method as described in claim 1, wherein, The method includes cooling the syngas to a first temperature without causing water vapor condensation before passing the syngas over the water-gas shift catalyst.
3. The method according to any one of claims 1 to 2, wherein, The dried, shifted synthesis gas produced includes In the first cooling unit (206), the converted synthesis gas is cooled to a condensation point at a second temperature to form a liquid condensate; as well as In the condensate separator (208), the liquid condensate is separated from the shifted synthesis gas to produce the dry shifted synthesis gas.
4. The method according to any one of claims 1 to 2, wherein, The method includes In the second cooling unit (216), the effluent from the cooled methanol synthesis reactor (214) is cooled to a condensation point at a third temperature to produce a condensate containing crude methanol and water; and In a methanol separator (218), the crude methanol is separated from the unreacted syngas.
5. The method of claim 4, wherein, The method includes The first portion of the unreacted syngas from the methanol separator (218) is sent as the cyclic syngas to the cyclic compressor (104, 210). A second portion of the unreacted syngas from the methanol separator (218) is sent to the hydrogen recovery unit (114, 220); and In the hydrogen recovery unit (114, 220), the hydrogen-rich product is generated, which is then mixed with the circulating synthesis gas flow into the circulating compressor (104, 210) to form a mixed synthesis gas flow.
6. The method according to any one of claims 1 to 2, wherein, The method involves compressing the mixed synthetic gas flow by increasing the pressure of the mixed synthetic gas flow in the circulating compressor (104, 210).
7. The method according to any one of claims 1 to 2, wherein, The method includes Mix the hydrocarbon stream and the oxygen stream with steam; and / or The hydrocarbon stream and / or the oxygen stream are preheated and then supplied to the non-catalytic partial oxidation (POX) chamber (102, 202) for the non-catalytic partial oxidation (POX) process.
8. The method according to any one of claims 1 to 2, wherein: (i) Cooling the converted syngas to its condensation point and separating the liquid condensate from the converted syngas; and (ii) Cool the methanol synthesis reaction effluent to its condensation point and separate the crude methanol from the unreacted synthesis gas. It is performed on the apparatus shared by (i) and (ii).
9. The method according to any one of claims 1 to 2, wherein, The water-gas shift reactor (204) and the cooled methanol synthesis reactor (214) share a common coolant and steam generation system.
10. The method according to any one of claims 1 to 2, wherein, The water-gas shift reactor (204) and the cooled methanol synthesis reactor (214) are housed together in the same container.
11. The method according to any one of claims 1 to 2, wherein, The method includes operating the non-catalytic partial oxidation (POX) chamber (102, 202) and the water-gas shift reactor (204) under pressure conditions in the range of 30 bar to 90 bar.