Methanol rectification system with enhanced energy efficiency

Abstract

Systems and embodiments are disclosed for improving the energy efficiency of a chemical separation plant through heat integration. Heat integration can provide a heat recycle between a rectification column and / or an integrated electrically heated component configured to provide heat to a reboiler in the chemical separation plant. The heat integration can utilize heat from a related chemical synthesis plant configured to perform an exothermic reaction (e.g., production of methanol from CO2 and H2). This integrated process design allows for the use of "low grade" heat, thereby improving energy efficiency. Furthermore, this integrated process design also allows for the exemplary chemical separation plant to be electrified, replacing the use of steam as a heating medium with a more energy efficient and carbon neutral method of electricity.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Provisional Patent Application US 63 / 624,046, filed January 23, 2024, entitled “Methanol Distillation System with Enhanced Energy Efficiency,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to a novel thermally integrated process design and system aimed at improving the energy efficiency of such equipment. For example, this integration can be used between (i) a chemical synthesis facility that generates heat through exothermic reactions (e.g., from methanol synthesis) and (ii) a chemical purification facility that requires energy to separate value-added products (e.g., high-purity methanol distillation). The system allows for heat exchange between these facilities to better maximize efficiency, reduce waste heat, lower cooling loads, etc. Furthermore, the thermally integrated process design and system described herein can completely or partially replace the need for steam as a heat source. Background Technology

[0003] Global climate change has been recognized as "the most pressing environmental challenge of our time." NASA states that "there is solid scientific evidence of a warming climate system." Climate change stems from the warming effects of greenhouse gases such as water vapor, nitrous oxide, methane, and carbon dioxide. Among these greenhouse gases, carbon dioxide emissions are the primary cause; since the beginning of the industrial era, the global atmospheric CO2 concentration has increased by one-third. CO2 emissions are mainly due to human activities, such as the combustion of fossil fuels, whose byproducts are released into the atmosphere.

[0004] Human industries across all sectors have faced ongoing pressure to reduce their carbon footprint. Proposed approaches include carbon capture technologies and a transition to renewable energy sources that do not emit CO2 as a byproduct during use. Converting CO2 into methanol is a promising carbon capture method that can reduce net emissions and store renewable energy in chemical bonds. Methanol is an important synthetic raw material for transportation fuels, industrial chemicals (e.g., formaldehyde), and plastics, coatings, textiles, and other synthetic products, and is an effective alternative for reusing or reducing CO2 emissions. Storing renewable energy in the chemical bonds of methanol addresses many transportation challenges associated with renewable electricity. For example, methanol's superior energy density and liquid state, its compatibility with transportation fuels, and low loss during transport make it an advantageous energy storage medium.

[0005] Furthermore, given the enormous scale of global methanol demand—200,000 tons per day and still growing—transferring CO2 from the atmosphere to methanol could potentially recover significant amounts of climate-causing greenhouse gases. Methanol also has enormous growth potential as a transportation fuel. Another growing use of methanol includes the methanol-to-olefins (MTO) process, which converts methanol into polyolefins, the building block of plastics, which are among the most common plastic products with ever-increasing global demand.

[0006] In industrial environments, methanol is typically produced from syngas, a combination of varying amounts of H2, CO, and CO2, usually derived from coal gasification. Methanol synthesis is an exothermic reaction, resulting in the generation of significant amounts of heat in the methanol synthesis equipment. Methanol produced in this manner often contains unintended contaminants such as water and dissolved gases (e.g., CO and CO2), referred to herein as crude methanol. Therefore, crude methanol requires purification.

[0007] Methanol purification is an energy-intensive process that requires heat input to separate methanol from water and other byproducts. Methanol purification typically takes place in distillation columns and associated facilities, requiring approximately 4.2 MJ / kg of energy to produce purified methanol. This high energy input reduces the potential carbon footprint of the equipment, necessitating more efficient methods and / or systems to minimize any required net energy input. Summary of the Invention

[0008] This invention proposes systems and methods for improving inter-process thermal efficiency through thermal integration. For example, in one specific embodiment, excess heat from an ETL (Exhaust-to-Liquid) unit (e.g., the applicant's Emissions-to-Liquids (ETL) unit) used to convert CO2 emissions and hydrogen (e.g., from water electrolysis) for methanol production can be integrated with a methanol purification unit. While this description is based on such a process scenario, it is understood that integration can also be achieved in various other chemical synthesis or other equipment. For instance, heat from the ETL unit, generated since methanol synthesis is an exothermic reaction, can be used in the distillation process of the methanol purification unit, for example, to power the reboiler of the distillation column, thereby heating the methanol / water / contaminant mixture to power the distillation process.

[0009] Heat from heat-generating equipment is typically characterized by temperature. Higher-temperature heat is referred to as having higher quality or "grade." In this invention, "low-grade" heat is considered to be heat below about 150°C, and "high-grade" heat is considered to be heat above about 150°C. 150°C is a typical temperature capable of powering the methanol purification process that can be used in the embodiments described herein. Low-grade heat is generally considered uneconomical to utilize and is often dissipated into the environment as "waste heat" in many industrial processes. This invention describes novel methods and processes for designing chemical separation equipment that can economically utilize low-grade heat as a heat source in certain parts of the process. Specifically, the embodiments described herein open or find a "cryogenic window" in the chemical separation equipment, allowing the utilization of low-grade heat to provide partial or full power for energy-intensive steps through thermal integration with another part of the process used to generate low-grade heat. Furthermore, the embodiments described herein can include internal thermal integration between different components of the chemical separation equipment, thereby improving energy efficiency and eliminating the need for supplemental external energy inputs.

[0010] In one embodiment, the chemical separation apparatus is designed to open a cryogenic window utilizing low-grade heat as a heat source through a three-tower separation design, wherein the chemical separation apparatus includes a first tower, a second tower, and a third tower. The first tower is configured to receive a chemical process stream (e.g., a crude methanol stream), and the first tower also includes at least one condenser unit (e.g., located at the top of the tower) and at least one reboiler configured to receive low-grade heat (e.g., low-grade heat from an ETL or other exothermic chemical synthesis apparatus). The second tower is configured to receive the bottoms fraction from the first tower, and the second tower also includes at least one condenser unit (e.g., located at the top of the tower) and at least one reboiler configured to receive heat from at least one condenser unit of the third tower. The third tower is configured to receive the bottoms fraction from the second tower, and the third tower also includes at least one condenser unit (e.g., located at the top of the tower) and at least one reboiler configured to receive high-grade heat (e.g., high-grade heat from an ETL or other exothermic chemical synthesis apparatus or other sources).

[0011] This implementation distributes the heat load required to separate the chemical process stream across three columns, opening a low-temperature window in the reboiler of the column receiving the chemical process stream with a higher concentration of volatile materials. In other words, in the first column where a higher concentration of volatile materials is present, lower-grade heat can be used to produce some fractions of the purified product stream (e.g., purified methanol), rather than requiring higher-grade heat as in the downstream separation columns.

[0012] In another exemplary embodiment, the chemical separation device is designed to use a side-stream reboiler. ofThe design opens a low-temperature window where low-grade heat can be used as a heat source, wherein the chemical separation apparatus includes: a first column configured to receive a chemical process stream (e.g., crude methanol stream), wherein the first column further includes at least one condenser unit (e.g., located at the top of the column) and at least one reboiler configured to receive heat from at least one condenser unit of a second column; a second column configured to receive the bottom fraction from the first column, wherein the second column further includes at least one condenser unit (e.g., located at the top of the column), a first reboiler associated with the bottom of the second column, and a second reboiler associated with the middle of the second column; a plurality of heat exchangers, wherein a first heat exchanger is configured to supply a high-grade heat source (e.g., high-grade heat from an ETL or other exothermic chemical synthesis apparatus or other source) to the first reboiler of the second column, a second heat exchanger is configured to supply a low-grade heat source (e.g., low-grade heat from an ETL or other exothermic chemical synthesis apparatus) to the second reboiler of the second column, and a third heat exchanger is configured to transfer heat from the condenser unit of the second column to the reboiler of the first column.

[0013] This implementation opens a low-temperature window in the second reboiler of the second column by placing a second reboiler in the middle of the second column (i.e., the second reboiler introduces the heated fluid into the middle of the second column, rather than the bottom). This design adds an additional reboiler that delivers a fluid temperature (e.g., between about 90°C and 140°C, between about 100°C and 130°C, or between about 110°C and 120°C) lower than the fluid temperature delivered by the first reboiler (e.g., between about 125°C and 175°C, between about 135°C and 165°C, or between about 145°C and 155°C). Due to the location and lower temperature of the fraction supplied to the second column via the second reboiler (side-stream reboiler), a low-grade heat source can be used to provide some of the heat required in the distillation process, eliminating the need to use high-grade heat for the entire feed stream (which would otherwise have entered the column via the first reboiler).

[0014] These exemplary embodiments can be integrated with portions of the equipment that serve as both high-grade and low-grade heat sources. In one embodiment, a reactor configured to perform an exothermic reaction and produce high-grade heat (e.g., between about 210°C and 310°C, between about 230°C and 290°C, or between about 250°C and 270°C) is connected to a first heat exchanger. This first heat exchanger is connected to a reboiler in the integrated chemical separation equipment that requires high-grade heat (e.g., typically between about 170°C and 180°C). For example, this reboiler requiring high-grade heat could be the reboiler of the third tower in the aforementioned three-tower system, or the first reboiler of the second tower in the aforementioned side-stream reboiler system. In either case, this configuration satisfies the need to supply high-grade heat to the integrated separation equipment. A second heat exchanger is located downstream of the first heat exchanger, wherein the second heat exchanger can handle the same material flow as the first heat exchanger, but the high-grade heat has been extracted from the process flow. A second heat exchanger is connected to a low-temperature window in the integrated chemical separation unit (e.g., the reboiler of the first tower in the aforementioned three-tower unit, or the second reboiler of the second tower in the aforementioned side-stream reboiler unit) to supply low-grade heat (e.g., at a temperature of approximately 120°C to 135°C) where such low-grade heat can be utilized within the integrated chemical separation unit, providing at least a portion of the required heat. This configuration identifies a low-temperature window where such heat can be utilized and employs low-grade heat to meet this demand. By integrating the chemical synthesis unit with a chemical separation unit that can utilize low-grade heat, the integrated unit can achieve a significant reduction in heat load, for example, reducing the heat load for producing high-purity methanol from approximately 4.2 MJ / kg to zero or near zero (e.g., a heat load for producing high-purity methanol of less than 2, less than 1, less than 0.5, or less than 0.1 MJ / kg).

[0015] In some implementations, heat from the associated chemical synthesis equipment can be delivered to the reboiler of the chemical separation equipment via a direct process heating system, wherein hot gases or other fluids generated by the reactor can be directly coupled to the reboiler of the chemical separation equipment.

[0016] In some implementations, heat from the associated chemical synthesis equipment can be delivered to the reboiler of the chemical separation equipment via one or more heat medium circulation systems, wherein hot gases or other fluids generated by the reactor can be coupled to such heat medium circulation, which can also be coupled to the reboiler of the chemical separation equipment to provide it with heat.

[0017] Furthermore, some chemical separation equipment can reduce its carbon footprint by using renewable energy sources instead of burning fossil fuels to obtain the necessary heat or power. Additionally, for some facilities, obtaining steam as a heat source is not readily available. The embodiments described herein can reduce or eliminate the need for chemical separation equipment to use steam as a heat source and facilitate the electrification of chemical separation equipment. Other embodiments for electrifying exemplary chemical separation equipment are described below, thereby reducing or eliminating the need to use steam as a heat source.

[0018] In one exemplary embodiment, a chemical separation apparatus is designed to use electricity as a power source and reduce or eliminate the use of steam as a heat source. The chemical separation apparatus includes: a first column configured to receive a chemical process stream, the first column further including at least one condenser unit (e.g., located at the top of the column) and at least one reboiler; a second column configured to receive bottom fraction from the first column, the second column further including at least one condenser unit located at the top of the column and at least one reboiler; a heat exchanger configured to transfer heat from the condenser unit of the second column to the reboiler of the first column; and a heat source configured to provide heat to the reboiler of the second column.

[0019] In some implementations, the heat source can be a hot oil circulation system.

[0020] In some implementations, the heat source includes an electric reboiler, wherein the reboiler of the second tower also includes an electric coil configured to provide heat to the reboiler.

[0021] In some implementations, the heat source includes an electrified heat medium circulation system that includes piping, pumps, and electric heaters connected to the reboiler of the second tower.

[0022] In some implementations, the heat source includes a heat pump, which includes piping connected to the reboiler of the second tower, a compressor, and an expansion valve.

[0023] It is understood that the embodiments described herein are not limited to methanol purification processes, but can also be used for various other chemical processes that require or wish to improve the system and / or method for separating products from the process stream. Specific methods, embodiments, and variations of the system will be described in more detail in the following description. Furthermore, the heat-generating portion of such equipment is not limited to embodiments where the heat-generating portion of the equipment is for methanol synthesis processes. A wide variety of chemical synthesis processes (e.g., exothermic processes), such as processes that generate heat due to exothermic chemical reactions, can be used.

[0024] For example, an exemplary chemical separation apparatus may include a first column, a second column, and a third column, wherein the first column is configured to receive a chemical process stream and further includes at least one associated condensation unit (e.g., located at the top of the first column) and at least one reboiler configured to receive low-grade heat from a low-grade heat source. The second column may be configured to receive at least a portion of the bottom condensate from the first column, and the second column also includes at least one associated condensation unit (e.g., located at the top of the second column) and at least one reboiler configured to receive heat from the top fraction of the third column. The third column may be configured to receive at least a portion of the bottom condensate from the second column, and the third column also includes at least one associated condensation unit (e.g., located at the top of the third column) and at least one reboiler configured to receive high-grade heat from a high-grade heat source.

[0025] In any of the embodiments described, the first tower may further include at least one stripping unit located at the top of the first tower.

[0026] In any of the embodiments described, the chemical process stream may include crude methanol.

[0027] In any of the embodiments described, the purified methanol produced by the first column accounts for about 25% to about 40% of the purified methanol produced by the chemical separation unit.

[0028] In any of the embodiments described, the purified methanol produced by the second column accounts for about 30% to about 50% of the purified methanol produced by the chemical separation unit.

[0029] In any of the embodiments described, the purified methanol produced by the third column accounts for about 20% to about 30% of the purified methanol produced by the chemical separation unit.

[0030] In any of the embodiments described, the first tower may be a low-pressure tower.

[0031] In any of the embodiments described, the second tower may be a low-pressure tower.

[0032] In any of the embodiments described, the third tower may be a medium-pressure tower (e.g., its operating pressure may be higher than that of the first tower and / or the second tower).

[0033] In any of the embodiments described, the high-grade heat source may be a hot gas stream or other hot fluid stream generated by a chemical synthesis device.

[0034] In any of the embodiments described, the low-grade heat source may be a hot gas stream or other hot fluid stream generated by a chemical synthesis device, wherein any high-grade heat initially present in the hot gas stream or other hot fluid stream has been at least partially depleted.

[0035] In any of the embodiments described, the heat medium circulation can transfer high-grade heat from a high-grade heat source to at least one reboiler in the third column.

[0036] In any of the embodiments described, the heat medium circulation can transfer low-grade heat from a low-grade heat source to at least one reboiler of the first column.

[0037] In any of the embodiments described, the low-grade heat source from which heat is recovered may be a hot wastewater stream.

[0038] Another exemplary embodiment proposes a system for thermally integrating (i) a chemical synthesis apparatus that generates low-grade and high-grade heat through an exothermic reaction with (ii) any chemical separation apparatus described herein. The system may include: a reactor for carrying out the chemical synthesis, configured to generate a process stream; a first heat exchanger configured to transfer high-grade heat from the process stream to a reboiler in a third column; and a second heat exchanger located downstream of the first heat exchanger and configured to transfer remaining low-grade heat from the process stream to the reboiler in the first column.

[0039] Another exemplary embodiment proposes a chemical separation apparatus comprising: a first column configured to receive a chemical process stream, wherein the first column further includes at least one condensation unit (e.g., located at the top of the first column) and at least one reboiler; and a second column configured to receive at least a portion of the bottom condensate from the first column, wherein the second column further includes at least one condensation unit (e.g., located at the top of the second column), a first reboiler associated with the bottom fraction of the second column, and a second reboiler associated with the middle fraction of the second column. The apparatus also includes a plurality of heat exchangers, wherein a first heat exchanger is configured to supply a high-grade heat source to the first reboiler of the second column, a second heat exchanger is configured to supply a low-grade heat source to the second reboiler of the second column, and a third heat exchanger is configured to transfer heat from the top fraction produced from the second column to at least one reboiler of the first column.

[0040] In any of the embodiments described, the first tower may further include at least one stripping unit located at the top of the first tower.

[0041] In any of the embodiments described, the chemical process stream may include crude methanol.

[0042] In any of the embodiments described, the first tower may be a low-pressure tower.

[0043] In any of the embodiments described, the second tower may be a medium-pressure tower (e.g., its operating pressure is higher than that of the first tower).

[0044] Another exemplary embodiment proposes a system for thermally integrating (i) a chemical synthesis apparatus that generates low-grade and high-grade heat through an exothermic reaction with (ii) any chemical separation apparatus described herein. The system may include: a reactor for carrying out the chemical synthesis, configured to generate a process stream; a first heat exchanger configured to transfer high-grade heat from the process stream to a first reboiler of a second column; and a second heat exchanger configured downstream of the first heat exchanger to transfer remaining low-grade heat from the process stream to a second reboiler of the second column.

[0045] Another exemplary embodiment proposes a chemical separation apparatus comprising: a first column configured to receive a chemical process stream, the first column further comprising, for example, at least one condenser unit (e.g., located at the top of the first column) and at least one reboiler; a second column configured to receive at least a portion of the bottom condensate from the first column, the second column further comprising at least one condenser unit (e.g., located at the top of the second column) and at least one reboiler. The apparatus further comprises a heat exchanger configured to transfer heat from the top fraction produced by the second column to at least one reboiler of the first column; and an electric heat source configured to provide heat to at least one reboiler of the second column.

[0046] In any of the embodiments described, the electric heat source may include a hot oil circulation system, which includes piping, a pump, and an electric heater connected to at least one reboiler of the second tower.

[0047] In any of the embodiments described, the electric heat source may include an additional reboiler, which further includes an internal electric heater.

[0048] In any of the embodiments described, the electric heat source may include a heat medium circulation system, which includes piping, a pump, and an electric heater connected to at least one reboiler of the second tower.

[0049] In any of the embodiments described, the electric heat source may include a heat pump, which includes piping, a compressor, and an expansion valve connected to at least one reboiler of the second tower.

[0050] In any of the embodiments described, the electric heating source may not contain or use steam.

[0051] In any of the embodiments described, the chemical separation equipment may be a methanol distillation equipment.

[0052] In any of the embodiments described, the first tower may further include at least one stripping unit located at the top of the first tower.

[0053] These and other features, aspects and advantages of the invention will become clearer and more readily understood in conjunction with the following description, the accompanying claims and drawings. Attached Figure Description

[0054] Figure 1A An exemplary chemical separation apparatus is schematically shown, designed to utilize low-grade heat using a three-tower design and direct process heating.

[0055] Figure 1B It schematically shows a kind of... Figure 1A The equipment is similar to chemical separation equipment, but it includes heat medium circulation instead of direct process heating.

[0056] Figure 2 An exemplary chemical separation apparatus is schematically shown, which is designed to utilize low-grade heat by implementing a side-stream reboiler design.

[0057] Figure 3A It schematically shows a kind of Figure 1A A system that integrates chemical separation equipment with methanol synthesis (e.g., ETL) equipment.

[0058] Figure 3B It schematically shows a kind of Figure 1B A system that integrates chemical separation equipment with methanol synthesis (e.g., ETL) equipment.

[0059] Figure 3C.1 , Figure 3C.2 and Figure 3C.3 This schematically illustrates a method for transferring heat directly from the methanol cycle or other chemical synthesis to the purification section of the system.

[0060] Figure 4A It schematically shows a kind of Figure 2 A system that integrates chemical separation equipment with methanol synthesis (e.g., ETL) equipment.

[0061] Figure 4B and Figure 4C The diagrams illustrate the relationship between the two. Figure 2 and Figure 4A It is a similar system to the one in China, but a heat pump is added to improve the quality of low-grade heat without changing the original heat medium circulation.

[0062] Figure 5 This schematically illustrates a chemical separation device that uses steam to power a chemical separation process.

[0063] Figure 6 This schematically illustrates a chemical separation device that utilizes hot oil circulation to provide heat for a chemical separation process.

[0064] Figure 7This schematically illustrates a chemical separation apparatus that utilizes an electric reboiler to provide heat for a chemical separation process.

[0065] Figure 8 The diagram schematically illustrates a chemical separation device that utilizes an electrified heat medium circulation to provide heat for a chemical separation process.

[0066] Figures 9A-9B The diagram illustrates a chemical separation device that uses a heat pump to provide heat for a chemical separation process. Detailed Implementation

[0067] Various embodiments of the invention can be better understood by reading the following description in conjunction with the accompanying drawings (in which the same reference numerals refer to the same elements).

[0068] Various modifications and alternative configurations can be made to this invention. Only certain illustrative embodiments are shown in the accompanying drawings and described below. However, it should be understood that this invention is not intended to be limited to the disclosed embodiments; rather, it is intended to cover all modifications, alternative configurations, combinations, and equivalents that fall within the spirit and scope of this invention and are defined by the appended claims.

[0069] It should be understood that unless a term is defined in this invention as having the meaning described, it is not intended to directly or indirectly limit the meaning of a term to its conventional meaning.

[0070] All heat exchangers described herein can have any suitable heat exchanger configuration, any suitable characteristics, and can operate in any suitable manner. As a non-limiting example, any heat exchanger proposed can be a co-current heat exchanger, a counter-current heat exchanger, a finned tube heat exchanger or a finless tube heat exchanger, a shell-and-tube heat exchanger, a U-tube heat exchanger, a single-pass straight tube heat exchanger, a double-pass straight tube heat exchanger, a plate heat exchanger or a frame heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, or other forms of heat exchanger.

[0071] "Thermal integration" is a general term used to refer to any process that introduces heat from one process or system into another. The thermal integration described in embodiments of the present invention can be internal, meaning within a single, independent system or process; or external, meaning the introduction of heat from one independent system or process into another independent process or system. "Independent" means that the system or process can (and typically will) operate independently of another system or process, without needing to be associated with or combined with that other system or process (e.g., without needing to exchange material flows between these processes).

[0072] Although the apparatus for converting carbon dioxide and hydrogen (e.g., from water electrolysis) into methanol via emissions-to-liquid (ETL) is primarily described in embodiments of the invention as an apparatus that can benefit from the described configuration, it should be understood that other apparatus characterized by exothermic chemical reactions (and thus with available waste heat) may also be applicable. For example, other types of chemical synthesis apparatus that perform exothermic reactions as part of product synthesis (particularly those that use flue gas CO2 streams as reactants used in product synthesis) may also be applicable to the thermal integration described herein.

[0073] Similarly, in embodiments of the invention, the chemical distillation apparatus for separating high-purity methanol (e.g., approximately 99% purity) from a crude methanol process stream is primarily described as an apparatus that can benefit from the described configuration. That is, it should be understood that other chemicals (including other alcohols or other chemical materials requiring purification and / or separation) can also benefit from the described configuration.

[0074] In this article, "low-grade heat" refers to thermal energy that is generally considered waste heat, or thermal energy that has limited or no utility for a given process. "High-grade heat" refers to a heat source with a higher temperature that is generally recognized as useful for heating a given fluid in a given process. For example, low-grade heat can refer to a heat source below approximately 150°C, while high-grade heat can refer to a heat source above approximately 150°C.

[0075] The term "cryogenic window" in this article refers to a step in a given overall process (e.g., methanol purification) that can utilize a low-grade heat source to provide the required heat. This cryogenic window is characterized by a lower temperature and a lower energy grade required compared to process steps that require a higher temperature (higher energy grade) input.

[0076] Integrating available heat sources and heat requirements in a process is beneficial, especially when a low-temperature window can be found or opened (i.e., where low-grade heat can be used), because it improves the overall efficiency of energy use. For example, it reduces the external heat requirements of the chemical separation section of the process, while also reducing the cooling water requirements of the ETL or other chemical synthesis sections. These benefits can be achieved simultaneously because both high-grade and low-grade heat from the ETL or other chemical synthesis equipment can be used in the reboiler of the chemical separation equipment, providing the heat necessary to achieve the desired purification or separation process, while reducing the need for externally supplied heat. For example, methanol purification is an expensive process, typically requiring approximately 4.2 MJ / kg of energy to produce methanol. The thermal integration process described herein allows for a significant reduction in load, for example, by essentially eliminating the energy requirement of approximately 4.2 MJ / kg typically required for methanol production through the described thermal integration configuration.

[0077] Furthermore, by utilizing high-grade heat from the methanol synthesis reactor (or other similar exothermic reactor) and low-grade heat that would otherwise be released into the atmosphere or other cooling systems, embodiments of the present invention allow the chemical separation unit to operate entirely on the heat generated by the associated chemical synthesis unit (e.g., a methanol synthesis unit). This embodiment eliminates the need for steam, which is typically used to power chemical separation units. Therefore, embodiments of the present invention are particularly useful for units where steam may not be readily available or where a reduction in carbon footprint is desired, as steam generation typically requires significant fossil fuel inputs.

[0078] Figure 1A An exemplary operation of a chemical separation apparatus 100 is shown, which separates a process stream 113 (e.g., a process stream containing crude methanol) through a first column 101, a second column 105, and a third column 108. Column 101 is configured to receive the process stream 113 via a side inlet. Column 101 also includes a reboiler 102 (e.g., associated with the bottoms fraction of column 101) and a condenser unit 103 (associated with the top portion of column 101). At least a portion of the bottoms feed from column 101 is fed into the reboiler 102, which is configured to receive low-grade heat from outside the separation process (e.g., from a heat source of about 120°C to about 135°C, such as low-grade heat from an integrated ETL or other chemical synthesis apparatus) via stream 111a. This low-grade heat is sufficient to reboil the circulating bottoms stream. The heated process stream 113a returns to column 101, forming a vapor fraction and a bottoms condensate fraction within column 101. The vapor fraction is collected by condenser unit 103, and the bottom condensate settles to the bottom of first column 101, where a portion of the process stream is sent to column 105 and another portion is recycled through reboiler 102. Condenser unit 103 may be connected to stripping unit 104, which removes dissolved gases from the condensed vapor fraction to form high-purity distilled methanol 114 to be sent to storage units or other intended uses. An example of a stripping unit suitable for the embodiments described herein is described in the applicant's U.S. Patent US10,960,349, issued March 30, 2021, the entire contents of which are incorporated herein by reference. Any entrained gases (including methanol) contained in the stripping gas exiting stripping unit 104 may be sent to second condenser 130 to condense any methanol product entrained in the stripping gas.

[0079] In one exemplary embodiment, the high-purity distilled methanol 114 produced by column 101 may account for about 35% of the high-purity distilled methanol 114 produced by chemical separation unit 100, for example, between 25% and 40%.

[0080] In some implementations, tower 101 may be a low-pressure tower, for example, operating at 0 to about 0.5 bar (gauge pressure).

[0081] Column 105 is configured to receive at least a portion of the bottom condensate from column 101, for example, through a side inlet as shown. Column 105 also includes a reboiler 106 and a condensation unit 107. As shown, at least a portion of the bottom output stream from column 105 is fed to reboiler 106. Reboiler 106 also includes a heat exchanger connected to column 108 and receiving heat from the overhead vapor fraction produced by column 108, wherein the heat (e.g., the heat of condensation from overhead fraction 108a) is transferred in reboiler 106 to reboil the recirculated portion of the bottom condensate received from column 105. Reboiler 106 returns the heated stream 106a to column 105 to form both the vapor fraction and the bottom condensate within column 105. The vapor fraction from the top of column 105 is collected by condenser unit 107, condensed into high-purity distilled methanol 114, and sent to storage unit or other uses, while the condensed fraction from the bottom of column 105 settles to the bottom of column 105 and is split there. One part is circulated through reboiler 106, and the other part is sent to column 108 (preheated with hot wastewater in heat exchanger 119).

[0082] In some implementations, the high-purity distilled methanol 114 produced by column 105 may account for about 40% of the high-purity distilled methanol 114 produced by chemical separation unit 100, for example, between 30% and 50%.

[0083] In some implementations, tower 105 may be a low-pressure tower, for example, operating at 0 to about 0.5 bar (gauge pressure).

[0084] Column 108 is configured to receive at least a portion of the bottom condensate from column 105 via a side inlet. Column 108 also includes a reboiler 109 and a condensation unit (e.g., associated with or integrated into reboiler 106). At least a portion of the bottom fraction from column 108 is fed to reboiler 109, which is configured to receive high-grade heat (e.g., about 260°C to about 280°C) from an external heat source (e.g., hot gas from the methanol synthesis reactor of an ETL unit) via flow 110. The high-grade heat supplied to reboiler 109 boils the bottom condensate received from column 108. Reboiler 109 returns the heated condensate to column 108, producing a vapor fraction and a bottom fraction (primarily water) within the third column 108. The vapor fraction can be used to provide heat to reboiler 106 via a heat exchanger, where the heat of condensation is transferred to reboiler 106, and the condensed high-purity distilled methanol 114 is sent to a storage unit or other uses. The bottom fraction (mainly water) can be discharged from the equipment as wastewater stream 121 after recovering its heat in heat exchangers 119 and 120. The purpose of heat exchangers 119 and 120 is to recover heat from the wastewater from column 108. First, the hot wastewater is used in heat exchanger 119 to preheat the feed entering column 108. Then, the partially cooled wastewater is used in the heat exchanger to preheat the crude methanol feed stream entering column 101. Preheating the feed streams entering columns 108 and 101 respectively reduces the heat load required by the separation equipment; that is, this thermal integration reduces the heat input requirement and helps to achieve zero-load or near-zero-load distillation.

[0085] In some embodiments, the high-grade heat flow 110 provides sufficient energy to evaporate all or substantially all of the methanol remaining in the bottom condensate of the bottom stream 108b from column 108, thereby allowing substantially all of the methanol to be recovered in stream 114. In some embodiments, the high-purity distilled methanol 114 produced by column 108 may account for approximately 25% of the high-purity distilled methanol 114 produced by chemical separation unit 100, for example, between 20% and 30%.

[0086] In some implementations, tower 108 may be a medium-pressure tower, operating at a higher pressure than towers 101 and 105. For example, the third tower 108 may operate at a pressure of about 3 to about 3.5 bar (gauge pressure).

[0087] In some embodiments, stream 110 comprises a hot gas or hot fluid produced by an exothermic reaction, wherein stream 110 contains high-grade heat. For example, stream 110 may be cooled as it passes through reboiler 109 to form stream 111, wherein stream 111 may comprise medium-grade to low-grade heat. This feature of using high-grade heat to power the reboiler of the last column can be used in any of the embodiments described herein. Some embodiments may utilize direct process heating, wherein streams 110 and / or 111 are fed directly into a given reboiler or heat exchanger. Compared to heat medium circulation, using direct process heating eliminates the need for installing a dedicated heat medium circulation, thereby reducing the installation cost of a given system. Furthermore, using direct process heating can reduce the operating cost of a given system because direct process heating can reduce or eliminate the need for various pumps. However, embodiments involving closed heat medium circulation are also feasible, and such examples are described herein.

[0088] Figure 3A It shows a kind of Figure 1AThe system shown is similar to the thermally integrated system 300, but it specifically demonstrates integration with a chemical synthesis reactor (e.g., an ETL unit). This system can be described as a three-tower purification system employing direct heating and zero-steam distillation. Regarding the chemical synthesis section of the unit, the syngas feed 301 (e.g., H2 and CO2) is fed into compressor 302 and then heated in heat exchangers 303 and 304. The purpose of heat exchangers 303 and 304 is to preheat the syngas feed to be fed to reactor 305, thereby improving the energy efficiency of the process. The arrangement of the heat exchanger sequence (located downstream of the reactor) 109-304-102-303 improves the heat recovery rate from the ETL unit to the methanol separation unit. The syngas feed is ultimately provided to reactor 305 (e.g., a methanol conversion reactor), where an exothermic reaction occurs, converting the syngas feed 301 into crude methanol, which forms a high-grade heat stream 110. Stream 110 is fed to a heat exchanger associated with reboiler 109, where high-grade heat is transferred to reboiler 109 to produce a cooling stream 111 containing medium to low-grade heat. Stream 111 passes through heat exchanger 304 (e.g., preheating the synthesis gas stream before reaching reactor 305) and is then fed as stream 111a to a heat exchanger associated with reboiler 102, where low-grade heat is transferred to reboiler 102 to form cooling stream 112. Stream 112 is fed to heat exchanger 303 (preheating the synthesis gas stream before heat exchanger 304) and then to condenser 306. The stream exiting condenser 306 enters collection tank 307, where the top fraction 308 is discharged from the unit, and the bottom fraction (e.g., crude methanol) is fed as process stream 113 into the chemical separation section of the unit. For example, the composition of crude methanol stream 113 may contain 60-70% methanol, 30-40% water (by weight), and a small amount (negligible) of reaction byproducts.

[0089] It is understood that in the exemplary chemical separation apparatus 100, reboiler 102 may include a cryogenic window. Reboiler 102 receives the process stream with the highest methanol concentration and lowest boiling point, thus requiring only the lowest temperature energy input to separate most of the methanol from process stream 113. Therefore, stream 111a, which can provide sufficient heat for reboiler 102 (but not reboiler 109), is connected to reboiler 102. For example, in one embodiment, the minimum temperature required for reboiler 102 is 100°C, while the minimum temperature required for reboiler 109 is 160°C. In contrast to reboiler 102, reboiler 109 (connected to the third column 108) receives the bottom condensate fraction with the lowest total methanol concentration and highest boiling point, thus requiring the highest temperature input to separate the last remaining methanol from process stream 108b. Therefore, high-grade heat stream 110 is connected to reboiler 109 to maximize the utilization of the high-grade heat present in stream 110. In the exemplary chemical separation apparatus described herein, separation is performed by setting up three towers (e.g., instead of two) and separating steps that require less heat input from other steps that require more heat input, allowing the utilization of low-grade heat that is typically considered waste heat.

[0090] Figure 1B Another operating configuration of the chemical separation unit 100' is shown, wherein the chemical separation unit 100' also includes closed-loop heat medium circulation systems 115 and 117. Figure 1A Similar to the example, the chemical separation apparatus 100' is designed to separate process stream 113 via a first column 101, a second column 105, and a third column 108. Column 101 is configured to receive process stream 113 through a side inlet. Column 101 also includes a reboiler 102 and an associated condenser unit 103. At least a portion of the bottom fraction of column 101 is fed to reboiler 102, which is configured to receive low-grade heat from a heat medium circulation 117. Heat medium circulation 117 utilizes multiple heat exchangers to transfer heat from a low-grade heat source (e.g., low-grade heat from an ETL unit) to reboiler 102. Heat medium circulation 117 also includes a pump 118 and a heat medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water (e.g., demineralized water), or any other heat medium fluid. The low-grade heat delivered to reboiler 102 boils the process stream 113a received from column 101. Reboiler 102 returns the heated process stream 113a to column 101, where a vapor fraction and a bottom condensate fraction are formed. The vapor fraction is collected by condensation unit 103, and the bottom condensate fraction settles at the bottom of column 101. This bottom condensate fraction can be either fed into column 105 or recycled through reboiler 102. (As in...) Figure 1AAs described, condensation unit 103 can be connected to stripping unit 104, which removes dissolved gases from the condensed vapor fraction to produce high-purity distilled methanol 114 for storage or other uses. Any entrained gases (including methanol) contained in the stripping gas leaving stripping unit 104 can be sent to a second condenser 130 to condense any entrained methanol product in the stripping gas.

[0091] Such as combination Figure 1A As described, column 101 can be a low-pressure column. The high-purity distilled methanol 114 produced by column 101 can account for approximately 35% of the high-purity distilled methanol produced by chemical separation unit 100'.

[0092] The second column 105 is configured to receive at least a portion of the bottom condensate from column 101 via a side inlet. (As in combination) Figure 1A As described, column 105 also includes a reboiler 106 and an associated condenser unit 107. At least a portion of the bottom fraction of column 105 is fed to reboiler 106. Reboiler 106 also includes a heat exchanger coupled to the top fraction received from column 108, wherein the heat of condensation from the top fraction is transferred to reboiler 106 and used to boil the bottom condensate received from column 105. Reboiler 106 returns the heated condensate to column 105 to form a vapor phase fraction and a bottom condensate fraction within column 105. The vapor phase fraction from the top of column 105 is collected by condenser unit 107, condensed into high-purity distilled methanol 114, and sent to a storage unit or other uses. The bottom condensate settles at the bottom of column 105, and can be circulated through reboiler 106 or fed into column 108 (e.g., preheated with hot wastewater in heat exchanger 119).

[0093] In some embodiments, the high-purity distilled methanol 114 produced by column 105 may account for approximately 40% of the high-purity distilled methanol 114 produced by chemical separation unit 100'. In some embodiments, column 105 may be a low-pressure column.

[0094] and combination Figure 1ASimilarly described, column 108 is configured to receive the bottom condensate from column 105 via a side inlet. Column 108 also includes a reboiler 109. At least a portion of the bottom fraction of column 108 is fed to reboiler 109, which is configured to receive high-grade heat from heat medium circulation 115. Heat medium circulation 115 may utilize multiple heat exchangers to transfer heat from a high-grade heat source (e.g., a methanol conversion reactor in an ETL unit) to reboiler 109. Heat medium circulation 115 may also include a pump and a heat medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water, or other fluids. The high-grade heat delivered to reboiler 109 boils the bottom condensate received from column 108. Reboiler 109 returns the heated condensate to column 108 to form a vapor phase fraction and a bottom fraction (primarily water) within column 108. The vapor-phase overhead fraction is conveyed to reboiler 106 via a heat exchanger, where the heat of condensation is transferred to reboiler 106. The overhead fraction is ultimately condensed into high-purity distilled methanol 114 and sent to a storage unit or other uses. The bottom fraction settles at the bottom of column 108. The bottom condensate can be either recycled through reboiler 109 or treated as wastewater 121, where its heat is first recovered in heat exchangers 119 and 120 before being discharged from the equipment.

[0095] In some implementations, the heat medium circulation 115 can provide sufficient energy to evaporate all or substantially all of the methanol remaining in the bottom condensate received from column 105, thereby making the resulting wastewater stream 121 substantially methanol-free.

[0096] In some embodiments, tower 108 may be a medium-pressure tower, and the high-purity distilled methanol 114 produced may account for approximately 25% of the high-purity distilled methanol 114 produced by the chemical separation unit 100'.

[0097] Figure 3B It shows a kind of Figure 1BThe system shown is similar to the thermally integrated system 300', but it specifically demonstrates integration with a chemical synthesis reactor (e.g., an ETL device). This system can be described as a three-tower purification system with two heat medium cycles capable of operating at different temperatures and zero-vapor distillation. Regarding the chemical synthesis section of the device, the syngas feed 301 (e.g., H2 and CO2) is fed into compressor 302, then into heat exchangers 303, 304, and subsequently to reactor 305 (e.g., a methanol conversion reactor), where an exothermic reaction occurs, converting the syngas feed 301 into crude methanol, resulting in a stream 110' containing high-grade heat. Stream 110' is fed into heat exchanger 309, which is configured to deliver high-grade heat to heat medium cycle 115 to generate a cooling stream 111'. Stream 111' passes through heat exchanger 304 (e.g., for final preheating before reactor 305) and then to heat exchanger 310, which is configured to transfer low-grade heat to heat medium circulation 117 to generate cooling stream 112'. Stream 112' is sent to heat exchanger 303 (e.g., for initial preheating before reactor 305) and then to condenser 306. Stream exiting condenser 306 enters collection tank 307, where the top fraction 308 is discharged and the bottom fraction is sent as process stream 113 (e.g., crude methanol) to a chemical separation unit.

[0098] The heat medium circulation 115 uses pump 116 to pump the heat medium from heat exchanger 309 to reboiler 109, and pumps the cooled heat medium from reboiler 109 to heat exchanger 309. Similarly, the heat medium circulation 117 uses pump 118 to pump the heated heat medium from heat exchanger 310 to reboiler 102, and pumps the cooled heat medium from reboiler 102 to heat exchanger 310.

[0099] Using one or more heat medium circulations can simplify the design of individual reboilers, simplify the heating control system of individual reboilers, and reduce the differential pressure level on the shell and tube side of the heat exchanger associated with the reboiler to prevent scaling.

[0100] Figure 3C.1 , Figure 3C.2 and Figure 3C.3 The diagram schematically illustrates heat exchanger 309 and reboiler 109 in a conventional heat medium configuration, as well as other related mechanisms involved in transferring heat directly from the methanol cycle or other chemical synthesis to the purification section of the system. While a heat medium system (see...) can be used... Figure 3C.1 The standard approach typically involves heat from the methanol cycle being transferred to the purification section via a heat carrier fluid (e.g., demineralized water) using heat exchanger 309 and reboiler 109. However, alternative approaches exist where heat can be transferred more directly. Figure 3C.2 and Figure 3C.3In one example, schematically summarized, the inlet temperature of reboiler 109' (on the methanol cycle side) can be approximately between 260°C and 280°C (stream 110), while the outlet temperature of reboiler 109' can be approximately between 190°C and 210°C (stream 111). The temperature of the aqueous phase at the bottom of the column (within the rectification section) can be at its boiling point, for example, approximately 150°C at the operating pressure. In this case, the latent heat required to evaporate the fluid needed for the medium-pressure column is provided by the reboiler of the medium-pressure column. This direct heating arrangement reduces the required equipment, thereby reducing capital expenditure, as a complete heat transfer system (and all associated heat exchangers, piping, and pumps) is not required. The total heat required for the purification section can be provided by two reboilers. The first reboiler can utilize heat from the methanol cycle, and the second reboiler can use steam (or electricity, depending on the configuration). This heat recovery arrangement reduces the consumption of external utilities (steam or electricity) during normal operation. This configuration is described in this document.

[0101] Figure 2 An alternative configuration is shown, employing two separation columns (the last of which includes a side-stream reboiler), instead of... Figure 1A-Figure 1B and Figures 3A-3B The three-tower configuration shown. Figure 2 An exemplary operating scheme of this exemplary chemical separation apparatus 200 is shown, in which process stream 113 is separated via a first column 201 and a second column 205. Column 201 is configured to receive process stream 113 (e.g., crude methanol) via a side inlet. Column 201 also includes a reboiler 202 and an associated condenser unit 203. The reboiler 202 further includes a heat exchanger coupled to the vapor-phase overhead fraction from column 205, wherein the condensation heat of the overhead fraction from column 205 is transferred to the reboiler 202 and used to boil the portion of the bottom stream from column 201 passing through the reboiler 202 to form a vapor-phase overhead fraction and a bottom condensate fraction within column 201. The bottom condensate fraction settles at the bottom of column 201, wherein the bottom condensate fraction can be either recycled through the reboiler 202 or fed into column 205 (preheated with hot wastewater in heat exchanger 211). The overhead fraction is collected by the condenser unit 203. The condenser unit 203 is optionally connected to the stripping unit 204, which removes dissolved gases from the overhead fraction to produce high-purity distilled methanol 114 that can be sent to a storage unit or for other uses. Any entrained gases (including methanol) contained in the stripping gas leaving the stripping unit 204 can be sent to a second condenser 230 to condense any entrained methanol product in the stripping gas.

[0102] In some implementations, tower 201 may be a low-pressure tower.

[0103] Column 205 is configured to receive the bottom condensate from column 201 via a side inlet. Column 205 also includes a first reboiler 206, a second reboiler 207, and an associated condensation unit (e.g., in series with reboiler 202). The bottom fraction from column 205 is fed to reboiler 206, which is configured to receive high-grade heat from heat medium circulation 208. Heat medium circulation 208 utilizes multiple heat exchangers to transfer heat from a high-grade heat source (e.g., a methanol conversion reactor in an ETL unit) to reboiler 206. Heat medium circulation 208 also includes a pump 211 (e.g., ...). Figure 4A (As shown) and a heat medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water, or other fluids. Although a closed heat medium loop is shown, it should be understood that a direct heating configuration, such as combined with... Figure 1A and Figure 3A As shown and described, the high-grade heat supplied to reboiler 206 boils the condensate received from column 205. Reboiler 206 returns the heated condensate to column 205 to form a vapor-phase overhead and bottom fraction within column 205. The side outlet material in column 205 is fed to reboiler 207, which is configured to receive low-grade heat from an external heat source (e.g., waste heat from an ETL unit) via stream 209 to boil the middle fraction flowing upward through column 205. Streams 209 and 210 can be open-type direct heating schemes (e.g., as shown in the image). Figure 4A (As shown), it can also be a closed heating cycle. Reboiler 207 returns the heated middle fraction to the middle section of column 205 (therefore, reboiler 207 is also called a "side-stream reboiler") to further promote the formation of vapor-phase overhead and bottom fractions within column 205. The vapor-phase overhead fraction is sent to reboiler 202, where the heat of condensation is transferred to reboiler 202, and the overhead fraction is finally condensed into high-purity distilled methanol 114, which is sent to a storage unit or other uses. The bottom fraction settles at the bottom of column 205, where it can be either recycled through reboiler 206 or treated as wastewater stream 221, where its heat is first recovered in heat exchangers 211 and 212 before being discharged from the equipment.

[0104] In some implementations, tower 205 can be a medium-pressure tower.

[0105] Figure 4A It shows a kind of Figure 2The system shown is similar to the thermally integrated system 400, but it specifically demonstrates integration with a chemical synthesis reactor (e.g., an ETL device). This system can be described as a zero-vapor distillation purification system with a side-stream reboiler. Regarding the chemical synthesis section of the device, syngas feed 301 (e.g., H2 and CO2) is fed into compressor 302 and then conveyed via heat exchangers 303 and 304 to methanol conversion reactor 305, where an exothermic reaction occurs, converting syngas feed 301 into crude methanol, forming a stream 110' containing high-grade heat. Stream 110' is fed into heat exchanger 309, which is configured to deliver high-grade heat to heat medium circulation 208 to form a cooling stream 111'. Stream 111' passes through heat exchanger 304 and then to a heat exchanger associated with reboiler 207 to transfer low-grade heat to reboiler 207, thereby forming a cooling stream 112''. Stream 112'' is sent to heat exchanger 303 and then to condenser 306. The stream leaving condenser 306 enters collection tank 307, in which the top fraction 308 is discharged and the bottom fraction is sent as process stream 113 (e.g., crude methanol) to a chemical separation unit.

[0106] The heat medium circulation 208 uses pump 213 to pump the heated heat medium from heat exchanger 309 to reboiler 206, and to pump the cooled heat medium from reboiler 206 to heat exchanger 309. Although Figure 4A The diagram shows a direct heating configuration associated with supplying low-grade heat to the side-line reboiler 207, but it should be understood that a closed heating cycle (e.g., with) can also be used. Figure 3B (Similar to cycle 117 shown).

[0107] It is understood that in the exemplary chemical separation apparatus 200, reboiler 207 (connected to column 205) may include a cryogenic window. Reboiler 207 receives a liquid fraction discharged from the middle section of column 205, wherein the temperature of this liquid fraction is lower than the temperature of the bottom fraction of column 205. In one embodiment, the temperature of the middle section of the column (from which the middle fraction is discharged to the side-stream reboiler 207) is typically between approximately 110°C and 120°C, while the temperature of the bottom of column 205 is typically between 145°C and 155°C. Therefore, the low-grade heat is sufficient to partially boil this portion of the lower-temperature fraction. Thus, a flow 111'' capable of providing sufficient heat to reboiler 207 (but not reboiler 206) is coupled to side-stream reboiler 207.

[0108] The thermal integration system described herein improves the overall energy efficiency of the equipment. Specifically, the discharge stream of reactor 305 is cooled by transferring high-grade and low-grade heat to strategically positioned reboilers within the chemical separation unit, thereby reducing the load required to cool the product discharge stream of the reactor and also reducing the load required to power the reboilers in the chemical separation section of the equipment. In some embodiments, by employing, for example... Figure 3A , Figure 3B and Figure 4A In the systems shown, all the heat required to perform the chemical separation process in chemical separation units 100 and 200 can be provided by an integrated ETL or other exothermic chemical synthesis unit. In these embodiments, the need for steam as a heat source is replaced or completely eliminated. Other embodiments described below present alternative designs in which the need for steam as a heat source can be replaced.

[0109] Figure 4B and Figure 4C The diagrams illustrate the relationship between the two. Figure 2 and Figure 4A A similar system, but with the addition of a heat pump to improve the grade of low-grade heat without changing the... Figure 2 and Figure 4A The system shown has an existing heat transfer medium circulation. For example, such a system can be described as a dual-tower (discrete-tower) design with the addition of a heat pump to improve the grade of low-grade heat. This scheme is based on... Figure 4A (A dual-tower side-stream reboiler scheme) in which the aforementioned side-stream reboiler is moved from the middle fraction to the bottom fraction, referred to herein as the "second reboiler," thereby no longer directly utilizing low-grade heat, but instead raising the low-grade heat to approximately the same temperature level as the first reboiler via a heat pump circuit (e.g., including an evaporator, compressor, condenser, and expansion valve). This adds a second reboiler whose delivered stream has a similar quality (temperature) to the stream delivered by the first reboiler (e.g., between approximately 125°C and 175°C, between approximately 135°C and 165°C, or between approximately 145°C and 155°C). Due to the presence of the heat pump, a portion of the heat required for the distillation process can be provided using a low-grade heat source, without needing to use high-grade heat for the entire feed stream (which would otherwise have entered the tower via the first reboiler). The use of the heat pump circuit can eliminate or reduce the use of input steam, while also effectively utilizing the additional electricity required to operate the compressor of the heat pump circuit. Figure 4B An exemplary chemical separation device is schematically shown, designed to utilize low-grade heat by incorporating a heat pump circuit comprising an evaporator, a compressor, a condenser (second reboiler), and an expansion valve. Figure 4C The diagram schematically illustrates a system in which... Figure 4BThe chemical separation equipment is integrated with methanol synthesis (e.g., ETL) equipment. Such a system can be described as a zero-vapor distillation purification system with a side-stream reboiler.

[0110] Those skilled in the art will understand that other heat pump solutions, as well as various temperature ranges, refrigerants, or refrigerant mixtures, can be employed. Implementation schemes incorporating heat pumps further achieve the goal of "fully electrified equipment" employing electric heating in different implementations. Compared to direct electric heating, heat pumps (which deliver electricity to the compressor in the heat pump circuit) have the potential to significantly reduce operating costs due to the thermodynamic advantages of moving heat compared to using electricity to create heat. Recent advancements in high-temperature heat pumps suitable for the temperature levels envisioned in this invention have made such implementations highly advantageous.

[0111] Figure 5 An exemplary chemical separation apparatus 500 is shown, which separates a process stream 113 (e.g., crude methanol) via a first column 501 and a second column 505. Column 501 is configured to receive the process stream 113 via a side inlet. Column 501 also includes a reboiler 502 and an associated condenser unit 503. The bottom fraction from column 501 is fed to the reboiler 502. The reboiler 502 includes a heat exchanger that provides heat to the material passing through the reboiler 502, the heat being provided by the vapor-phase overhead fraction from the second column 505, wherein the condensation heat of the vapor-phase overhead fraction from column 505 is transferred to the reboiler 502 and used to boil the bottom stream 501b to form a vapor-phase fraction and a bottom condensate fraction within column 501. The vapor-phase overhead fraction is collected by the condenser unit 503, and the bottom condensate fraction settles at the bottom of column 501. A portion of the bottom condensate is fed into column 505, while another portion is recycled back to column 501 via reboiler 502. A condensation unit 503 is optionally connected to a stripping unit 504, which removes dissolved gases from the condensed vapor fraction to produce high-purity distilled methanol 114 for storage or other uses. Any entrained gases (including methanol) contained in the stripping gas leaving stripping unit 504 can be fed to a second condenser 530 to condense any entrained methanol product in the stripping gas. In one embodiment, the stripping gas may include nitrogen, but it should be understood that other gases are also feasible.

[0112] In some implementations, tower 501 may be a low-pressure tower.

[0113] Column 505 is configured to receive the bottom condensate from column 501 via a side inlet. Column 505 also includes a first reboiler (e.g., a hot medium reboiler) 506, a second reboiler (e.g., a steam reboiler) 511, and an associated condensation unit associated with or downstream of reboiler 502. The bottom fraction of column 505 is fed to reboiler 506, which is configured to receive high-grade heat from hot medium circulation 507. Hot medium circulation 507 also includes a pump 508 and a hot medium (which can be any substance capable of transferring heat between heat exchangers, such as oil, water, or other fluids) to boil the condensate received from column 505. Hot medium circulation 507 utilizes heat exchanger 509 to transfer heat from a high-grade heat source (e.g., a methanol conversion reactor in an ETL unit) to the hot medium. Pump 508 circulates the heated hot medium to reboiler 506 and circulates the cooled hot medium back to heat exchanger 509. The high-grade heat supplied to reboiler 506 boils the condensate received from column 505. Reboiler 506 returns the heated condensate to column 505 to form vapor-phase overhead and bottom fractions within column 505. Another portion of the bottom fraction from column 505 is sent to reboiler 511, which is configured to receive heat from a steam heating accessory 514 (e.g., the illustrated steam boiler, steam condensate pump, and steam condensate tank), which is configured to boil and circulate steam and supply heated steam to reboiler 511. The heat supplied to reboiler 511 boils the condensate received from column 505. Reboiler 511 returns the heated condensate to column 505, further providing vapor-phase overhead and bottom fractions within column 505. The overhead fraction from the vapor column is collected in a condensation unit associated with (e.g., downstream of) reboiler 502, where heat from the overhead fraction stream is transferred to reboiler 502. The vapor column overhead fraction is condensed into high-purity distilled methanol 114 and sent to a storage unit or other uses. The bottom condensate from column 505 can be discharged from the equipment as wastewater or recycled through reboiler 506 and / or reboiler 511. Liquid can also be extracted from the bottom of column 505 or from heat exchanger 506, although this may be less convenient to operate.

[0114] Figure 5The configuration shown illustrates that the liquid is fed separately to reboilers 506 and 511 (e.g., they are in hydrostatic equilibrium, so the liquid can flow back and forth between 505, 506, and 511). In one embodiment, only the steam from the reboiler is returned to column 505. The liquid is drawn from reboiler 511 and discharged as wastewater after heat recovery via heat exchangers 517 and 518. That is, reboiler 506 boils the bottom fraction from column 505. The resulting steam is sent to column 505. The remaining liquid is sent to reboiler 511. The steam generated in reboiler 511 is sent to column 505. The remaining liquid that does not boil in reboiler 511 is discharged as wastewater (after heat recovery via heat exchangers 517 and 518). Alternatively, both water and steam from reboiler 506 can be returned to column 505, and then the liquid can be fed separately into reboiler 511. The liquid and steam from reboiler 511 are fed to column 505, and the liquid is eventually drawn from the bottom of column 505, but this may not provide any additional advantages. Of course, other configurations, such as drawing water from reboiler 506 and discharging it as wastewater, are also feasible.

[0115] An exemplary purpose of the heat exchangers 517 and 518 shown is to recover heat from the bottom aqueous phase of column 505. For example, it can be configured such that the hot bottom aqueous phase from column 505 is fed to heat exchanger 517, where heat is transferred from the hot bottom aqueous phase from column 505 to the cooler bottom condensate from column 501. The hot bottom condensate from heat exchanger 517 is then fed as feed into column 505.

[0116] Heat exchanger 518 receives partially cooled bottom aqueous phase (from column 505) from heat exchanger 517, and the heat is transferred to the cold crude methanol in stream 113. Hot stream 113 is then fed as feed to column 501. This heat recovery reduces the amount of heat that needs to be supplied to column 505 via heat exchangers 511 and 506.

[0117] Chemical separation equipment 500 is an exemplary chemical separation device that relies on steam-related ancillary facilities as a heat source. However, reliable steam sources may be difficult to obtain and / or may hinder carbon emission reductions. Other embodiments described below replace the need for steam-related ancillary facilities and allow for the integration of electrical energy sources, including renewable energy sources.

[0118] Figure 6 An exemplary operating scheme for a chemical separation device 600 is shown, which is an electrified alternative to a chemical separation device 500. For example... Figure 6As shown, the chemical separation apparatus 600 replaces reboiler 511 and its associated steam heating system 514 with reboiler 601, wherein reboiler 601 is configured to receive heat from hot oil circulation 602. Hot oil circulation 602 also includes a pump 603 and an electric heater 604, wherein heater 604 heats the oil in hot oil circulation 602, pump 603 circulates the heated oil from heater 604 to reboiler 601, and circulates cooled oil from reboiler 601 to heater 604. The heat delivered to reboiler 601 causes the condensate received from column 505 to boil. Reboiler 601 returns the heated condensate to column 505, further forming a vapor-phase overhead and bottom fraction within column 505. In one embodiment, only steam from 601 is sent to column 505. The liquid is drawn from reboiler 601 and discharged as wastewater after heat recovery in heat exchangers 517 and / or 518. The overhead fraction from the vapor column is fed to reboiler 502, where available heat from the stream is transferred to reboiler 502, where the overhead fraction is condensed into high-purity distilled methanol 114 and sent to a storage unit or other uses. The bottom condensate from column 505 can be discharged from the equipment as wastewater or recycled through reboilers 506 and / or 601. Figure 6 Only liquid is shown being drawn from reboiler 601; however, liquid can also be drawn from column 505 or reboiler 506 if desired.

[0119] In some implementations, heater 604 operates using electricity generated from renewable energy sources, thereby reducing any associated carbon footprint.

[0120] By replacing the steam-dependent heating system with a hot oil circulation powered by an electric heater, the chemical separation unit 600 eliminates the need for steam. Furthermore, since the heating element of the electric heater 604 does not directly contact the contents of the reboiler 601, the unit 600 reduces the likelihood of thermal degradation in the process stream 113.

[0121] Figure 7 An exemplary operating scheme for a chemical separation device 700 is shown, which is an electrified alternative to a chemical separation device 500. For example... Figure 7 As shown, the chemical separation unit 700 replaces reboiler 511 and its associated steam heating system 514 with reboiler 701, wherein reboiler 701 also includes an internal electric heater that boils the condensed fraction received from column 505. Reboiler 701 returns the heated condensed fraction to column 505, further forming a vapor-phase overhead fraction and a bottom fraction within column 505. The processing method of the overhead and bottom fractions is combined with... Figures 5-6 The methods described are the same.

[0122] By replacing the heating system, which relies on steam as a heat source, with a reboiler that includes an internal electric heater, the chemical separation unit 700 eliminates the need for steam. Due to its simple design and limited auxiliary facilities, the chemical separation unit 700 can significantly reduce installation and maintenance costs.

[0123] Figure 8 An exemplary operating scheme for a chemical separation device 800 is shown, which is an electrified alternative to a chemical separation device 500. For example... Figure 8 As shown, the chemical separation device 800 omits the reboiler 511 and its associated steam heating equipment 514, and adds an electric heater 801 to the heat medium circulation 507, wherein the electric heater 801 provides additional heat for the heat medium circulation and the reboiler 506.

[0124] By replacing the heating system that relies on steam as a heat source with an additional electric heater installed in the heat medium circulation, the chemical separation unit 800 eliminates the need for steam. This allows electrical energy to be used for the chemical separation process within the chemical separation unit 800.

[0125] Figures 9A-9B Other exemplary operating scenarios for exemplary chemical separation devices 900 and 900' are shown, which are electrification alternatives to chemical separation device 500. For example... Figures 9A-9B As shown, the chemical separation unit 900 / 900' omits the reboiler 511 and its associated steam heating system 514, and adds a compressor 901 (e.g., electrically powered) to the heat medium circulation 507 (which now functions as a heat pump), whereby the compressor 901 increases the pressure of the heat medium. Heat from the circulating gas cooler 509 (used for evaporating the heat medium) can optionally be supplemented from the electric heater 801 (…). Figure 9A The heat of the medium is then evaporated and raised to a higher temperature in compressor 901, thus enabling its use in reboiler 506. Figure 9B The system 900', excluding the electric heater 801, is shown, while Figure 9A The system 900 includes the optional electric heater 801. Any fluid capable of efficiently absorbing and releasing heat during repeated phase changes (from liquid to vapor and vice versa) can be used as the heat medium fluid in a heat medium circulation. Figure 9B The configuration shown without the electric heater 801 may be more practical and simpler.

[0126] By replacing the heating system that relies on steam as a heat source with a compressor 901 (e.g., electrically powered) and an expansion valve 902, the chemical separation unit 900 / 900' eliminates the need for steam, allowing the heat medium circulation to function as a heat pump. This enables the use of electrical energy for the chemical separation process in the chemical separation unit 900 / 900'.

[0127] The features of the disclosed embodiments can be combined or arranged to achieve specific advantages that can be understood by those skilled in the art from this invention. Similarly, the features of the disclosed embodiments may provide independent advantages applicable to other embodiments not detailed herein.

[0128] It should be understood that not all objectives or advantages can be achieved under any embodiment of this disclosure. Those skilled in the art will recognize that the system and method can be embodied or implemented in a way that achieves or optimizes one or more of the taught advantages without achieving other taught or suggested objectives or advantages.

[0129] Skilled artisans will recognize the interchangeability of the various features disclosed. In addition to the variations described, those skilled in the art can mix and match other known equivalents of each feature to create or use integrations of thermal, steam, and / or other heated working fluids falling under the principles of this disclosure. Those skilled in the art will understand that the features are applicable to other systems and processes. Therefore, this disclosure and its embodiments and variations are not limited to methanol synthesis processes or specific cooperative plants, but can be utilized through thermal integration between any exothermic chemical process that generates waste heat and any partner process that generates high-value steam or other high-value working fluid / heating medium.

[0130] While this disclosure describes certain exemplary embodiments and examples of thermal integration, those skilled in the art will understand that this disclosure extends beyond the specific disclosed embodiments to other alternative embodiments and / or uses of this disclosure and its obvious modifications and equivalents. This disclosure should not be limited to the specific disclosed embodiments described above.

[0131] Furthermore, unless otherwise stated, the quantities, ingredients, and distances expressed in this specification and claims are all consistent. The numerical values ​​of a quantity, value, or other measurement should be understood to be optionally modified by the term "about" or its synonyms. When the terms "about," "approximately," "generally," or similar terms are used with the stated quantity, value, or condition, they can be understood as deviations from the stated quantity, value, or condition of less than 20%, less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01%. As used herein, the term "between" includes any of the referenced endpoints. For example, "between 2 and 10" includes both 2 and 10.

Claims

1. A chemical separation device, comprising: The first tower, the second tower, and the third tower, among which: The first tower is configured to receive a chemical process stream, and the first tower further includes, for example, at least one associated condensation unit located at the top of the first tower, and at least one reboiler configured to receive low-grade heat from a low-grade heat source. The second column is configured to receive at least a portion of the bottom condensate from the first column, and the second column further includes, for example, at least one associated condensation unit located at the top of the second column, and at least one reboiler configured to receive heat from the top fraction of the third column. The third column is configured to receive at least a portion of the bottom condensate from the second column, and the third column further includes, for example, at least one associated condensation unit located at the top of the third column, and at least one reboiler configured to receive high-grade heat from a high-grade heat source.

2. The chemical separation equipment according to claim 1, characterized in that, The first tower also includes at least one stripping unit located at the top of the first tower.

3. The chemical separation equipment according to claim 1, characterized in that, The chemical process stream includes crude methanol.

4. The chemical separation equipment according to claim 3, characterized in that, The purified methanol produced by the first tower accounts for approximately 25% to approximately 40% of the purified methanol produced by the chemical separation equipment.

5. The chemical separation equipment according to claim 3, characterized in that, The purified methanol produced by the second tower accounts for approximately 30% to approximately 50% of the purified methanol produced by the chemical separation equipment.

6. The chemical separation apparatus according to claim 3, characterized in that, The purified methanol produced by the third tower accounts for approximately 20% to approximately 30% of the purified methanol produced by the chemical separation equipment.

7. The chemical separation equipment according to claim 1, characterized in that, The first tower is a low-pressure tower.

8. The chemical separation equipment according to claim 1, characterized in that, The second tower is a low-pressure tower.

9. The chemical separation equipment according to claim 1, characterized in that, The third tower is a medium-pressure tower.

10. The chemical separation apparatus according to claim 1, characterized in that, The high-grade heat source is a hot gas flow or other hot fluid flow generated by chemical synthesis equipment.

11. The chemical separation apparatus according to claim 1, characterized in that, The low-grade heat source is a stream of hot gas or other hot fluid generated by a chemical synthesis device, wherein any high-grade heat initially present in the hot gas or other hot fluid has been at least partially depleted.

12. The chemical separation apparatus according to claim 10, characterized in that, The heat medium circulation transfers high-grade heat from the high-grade heat source to at least one reboiler of the third column.

13. The chemical separation apparatus according to claim 11, characterized in that, The heat medium circulation transfers low-grade heat from the low-grade heat source to at least one reboiler of the first column.

14. The chemical separation apparatus according to claim 11, characterized in that, The low-grade heat source from which heat is recovered is the hot wastewater stream.

15. A system for thermally integrating a chemical synthesis apparatus that generates low-grade heat and high-grade heat through an exothermic reaction with a chemical separation apparatus according to claim 1, the system comprising: A reactor for carrying out chemical synthesis, the reactor being configured to generate a process flow; A first heat exchanger is configured to transfer high-grade heat from the process stream to the reboiler of the third column. as well as A second heat exchanger is disposed downstream of the first heat exchanger and configured to transfer the remaining low-grade heat in the process stream to the reboiler of the first column.

16. A chemical separation apparatus, comprising: A first column, configured to receive a chemical process stream, wherein the first column further includes, for example, at least one condensation unit located at the top of the first column, and at least one reboiler; A second column, configured to receive at least a portion of the bottom condensate from the first column, wherein the second column further includes, for example, at least one condensation unit located at the top of the second column, a first reboiler associated with the bottom fraction of the second column, and a second reboiler associated with the middle fraction of the second column. as well as Multiple heat exchangers, including: The first heat exchanger is configured to supply high-grade heat to the first reboiler of the second column. The second heat exchanger is configured to supply low-grade heat to the second reboiler of the second column. The third heat exchanger is configured to transfer the heat from the overhead fraction produced from the second column to at least one reboiler of the first column.

17. The chemical separation apparatus according to claim 16, characterized in that, The first tower also includes at least one stripping unit located at the top of the first tower.

18. The chemical separation apparatus according to claim 16, characterized in that, The chemical process stream includes crude methanol.

19. The chemical separation apparatus according to claim 16, characterized in that, The first tower is a low-pressure tower.

20. The chemical separation apparatus according to claim 16, characterized in that, The second tower is a medium-pressure tower.

21. A system for thermally integrating a chemical synthesis apparatus that generates low-grade heat and high-grade heat through an exothermic reaction with a chemical separation apparatus according to claim 16, the system comprising: A reactor for carrying out chemical synthesis, the reactor being configured to generate a process flow; A first heat exchanger, configured to transfer high-grade heat from the process stream to a first reboiler in the second column, and A second heat exchanger is disposed downstream of the first heat exchanger and configured to transfer the remaining low-grade heat in the process stream to the second reboiler of the second column.

22. A chemical separation apparatus, comprising: A first column, configured to receive a chemical process stream, further comprising, for example, at least one condensation unit located at the top of the first column, and at least one reboiler; A second column, configured to receive at least a portion of the bottom condensate from the first column, further comprising, for example, at least one condensation unit located at the top of the second column, and at least one reboiler; A heat exchanger configured to transfer heat from the overhead fraction produced by the second column to at least one reboiler of the first column; as well as An electric heat source configured to provide heat to at least one reboiler of the second tower.

23. The chemical separation apparatus according to claim 22, characterized in that, The electric heat source includes a hot oil circulation system, which includes pipes, a pump, and an electric heater connected to at least one reboiler of the second tower.

24. The chemical separation apparatus according to claim 22, characterized in that, The electric heat source includes an additional reboiler, which further includes an internal electric heater.

25. The chemical separation apparatus according to claim 22, characterized in that, The electric heat source includes a heat medium circulation system, which includes pipes, a pump, and an electric heater connected to at least one reboiler of the second tower.

26. The chemical separation apparatus according to claim 22, characterized in that, The electric heat source includes a heat pump, which includes piping connected to at least one reboiler of the second tower, a compressor, and an expansion valve.

27. The chemical separation apparatus according to claim 22, characterized in that, The electric heating source does not contain steam.

28. The chemical separation apparatus according to claim 22, characterized in that, The chemical separation equipment is a methanol distillation equipment.

29. The chemical separation apparatus according to claim 22, characterized in that, The first tower also includes at least one stripping unit located at the top of the first tower.

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