Chemical separation apparatus and system for thermal integration

Abstract

The utility model relates to chemical separation equipment which comprises a first tower, a second tower and a third tower, the first column is configured to receive a chemical process stream and includes a condensation unit at a top end portion of the first column and a reboiler configured to receive low-grade heat from a low-grade heat source. The second column is configured to receive a bottom condensed fraction from the first column and includes a condensation unit located at a top end portion of the second column, and a reboiler configured to receive heat from a top fraction of the third column. The third column is configured to receive a bottom condensed fraction from the second column and includes a condensation unit located at a top end portion of the third column and a reboiler configured to receive high-grade heat from a high-grade heat source. The utility model further relates to a system for carrying out heat integration on chemical synthesis equipment for generating low-grade heat and high-grade heat in exothermic reaction and the chemical separation equipment.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application 63 / 624,046, filed January 23, 2024, entitled “Improved Methanol Distillation System for Increased Efficiency,” the entirety of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to new process designs and systems for heat integration aimed at increasing the energy efficiency of related equipment. By way of example, such integration can be between a chemical synthesis plant that generates heat from an exothermic reaction (e.g., methanol synthesis) and a chemical purification plant that requires energy to separate a high-value product (e.g., high-purity distilled methanol). The system can exchange heat between these plants in order to better increase efficiency, reduce waste heat, reduce cooling load, etc. Moreover, the heat-integrated process designs and systems described herein can completely or partially replace the need for steam as a heat source. BACKGROUND

[0004] Global climate change has been recognized as “the most pressing environmental challenge of our time.” Climate change is caused by the warming effect of greenhouse gases such as water vapor, nitrous oxide, methane, and carbon dioxide. Of these, CO2 emissions are the key culprit, as the concentration of CO2 in the global atmosphere has increased by one-third since the beginning of the industrial era. CO2 emissions primarily stem from human activities, such as the consumption of fossil fuels, the byproducts of which are emitted into the atmosphere.

[0005] Human industry has been under constant pressure to reduce its carbon footprint. Proposed methods include carbon capture technologies, as well as a shift to renewable energy sources that do not emit CO2 byproducts when used. Converting CO2 into methanol is a promising carbon capture method that both reduces net emissions and stores renewable energy in chemical bonds. Methanol is an important precursor to transportation fuels, industrial chemicals (e.g., formaldehyde), and plastics, paints, textiles, and other synthetics, making it an effective alternative for reusing CO2 or reducing CO2 emissions. The method of storing renewable energy in the chemical bonds of methanol addresses many of the issues with renewable electricity related to transportation. For example, methanol’s good energy density and liquid state, compatibility with transportation fuels, and low losses during transportation all make methanol a preferred energy storage medium.

[0006] Furthermore, given the large global demand for methanol (200,000 tons per day and growing), converting atmospheric CO2 into methanol has the potential to recover large amounts of the greenhouse gas responsible for climate change. Methanol also has significant growth potential as a transportation fuel. Another increasingly important attribute of methanol includes the methanol-to-olefins process, which converts methanol into the building blocks of polyolefins, the most common plastic product, with a growing global demand.

[0007] Methanol is typically produced in an industrial setting from synthesis gas, a combination of varying amounts of H2, CO, and CO2, often extracted from gasified coal. Methanol synthesis is an exothermic reaction, and thus the methanol synthesis equipment produces a significant amount of heat energy. Methanol produced in this manner typically contains unwanted impurities, such as water and dissolved gases, such as CO and CO2, referred to herein as crude methanol. As such, crude methanol requires purification.

[0008] Methanol purification is an energy-intensive process that requires input of heat to separate the methanol from water and other byproducts. Methanol purification is typically performed in distillation columns and related equipment, requiring approximately 4.2 megajoules per kilogram of methanol purified. This high energy input can impact the potential reduction of the carbon footprint of the equipment, and thus methods and / or systems that use energy more efficiently are needed to reduce the required net energy input. SUMMARY

[0009] The present disclosure relates to systems and methods that improve the utilization of heat energy between processes by integrating the heat between processes. For example, in one particular embodiment, excess heat from an ETL device (such as the Applicant's Emissions to Liquid (ETL) device) for converting CO2 emissions and hydrogen (such as hydrogen produced from water electrolysis) into methanol can be integrated with a methanol purification device. While described herein with respect to this scenario, it is understood that integration can occur in various other chemical synthesis or other devices. For example, heat produced by the ETL device (due to the exothermic nature of methanol synthesis) can be used in the distillation process of the methanol purification device, such as to power the reboiler of a distillation column, such as to heat the methanol / water / pollutant mixture to power the distillation process.

[0010] Heat from heat generating equipment is typically characterized in terms of temperature. The higher the temperature, the higher the quality or "grade" of the heat. In the present disclosure, "low grade" heat is considered to be heat below about 150 °C, while "high grade" heat is considered to be heat above about 150 °C. 150 °C is a typical temperature required to power the methanol purification process to which the embodiments described herein can be applied. The utilization of low grade heat is generally considered to be uneconomical, and in many industrial processes it is typically dissipated to the environment as "waste heat." The present disclosure describes new methods and new processes for designing chemical separation equipment in which low grade heat can be economically utilized as a heat source in certain parts of the process. Specifically, the embodiments described herein open or identify low temperature windows in chemical separation equipment through which low grade heat can be utilized to power, in part or in whole, high energy consuming steps by being thermally integrated with another part of the overall process that generates low grade heat. In addition, the embodiments described herein can also include internal thermal integration between different components of the chemical separation equipment, thereby improving energy efficiency without the need for supplemental external energy input.

[0011] In one embodiment, a chemical separation equipment is designed to open a low temperature window in which low grade heat can be utilized as a heat source through a three column separation design, in which the chemical separation equipment includes a first column, a second column, and a third column. The first column is configured to receive a chemical process stream (e.g., a crude methanol stream) and includes at least one condensing unit, e.g., at the top portion of the first column, and at least one reboiler configured to receive low grade heat (e.g., low grade heat from an ETL or other exothermic chemical synthesis equipment). The second column is configured to receive a bottom fraction from the first column and includes at least one condensing unit, e.g., at the top portion of the second column, and at least one reboiler configured to receive heat from at least one condensing unit of the third column. The third column is configured to receive a bottom fraction from the second column and includes at least one condensing unit, e.g., at the top portion of the third column, and at least one reboiler configured to receive high grade heat (e.g., high grade heat from an ETL or other exothermic chemical synthesis equipment or other facility).

[0012] The present embodiments distribute the load required to separate a chemical process stream into three columns, opening a low temperature window in the reboiler of the column that receives the chemical process stream with a high concentration of volatile species. In other words, in the first column in which there is a higher concentration of volatile species, a lower grade of heat can be used to produce a portion of the purified product stream (e.g., purified methanol) rather than the higher grade of heat required in the downstream separation columns.

[0013] In another exemplary embodiment, a chemical separation apparatus is designed to open a low temperature window by a side reboiler design to utilize low grade heat as a heat source, wherein the chemical separation apparatus comprises: a first column configured to receive a chemical process stream (e.g., a crude methanol stream) and comprising at least one condensing unit, e.g., at a top portion of the first column, and at least one reboiler configured to receive heat from at least one condensing unit of a second column; a second column configured to receive a bottom fraction from the first column and comprising at least one condensing unit, e.g., at a top portion of the second column, a first reboiler associated with a bottom fraction of the second column, a second reboiler associated with a middle fraction of the second column, and a plurality of heat exchangers, wherein a first heat exchanger is configured to deliver a high grade heat source (e.g., from an ETL or other exothermic chemical synthesis apparatus or otherwise) to the first reboiler of the second column, a second heat exchanger is configured to deliver a low grade heat source (e.g., 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 deliver heat from the condensing unit of the second column to the reboiler of the first column.

[0014] By positioning the second reboiler in the middle of the second column (i.e., the second reboiler introduces a heated stream into the middle of the second column rather than the bottom of the column), the present embodiment opens a low temperature window in the second reboiler of the second column. This design adds an additional reboiler that delivers a stream at a lower temperature (e.g., about 90°C to 140°C, about 100°C to 130°C, or about 110°C to 120°C) than the temperature of the stream delivered by the first reboiler (e.g., about 125°C to 175°C, about 135°C to 165°C, or about 145°C to 155°C). Because of the location and reduced temperature of the fraction provided to the second column by the second reboiler (side reboiler), a low grade heat source can be used to provide a portion of the heat required in the distillation process without requiring a high grade heat source for the entire feed stream to the column via the first reboiler.

[0015] These exemplary embodiments can be integrated with the portion of the apparatus that serves as the high and low grade heat source. In one embodiment, a reactor configured to perform an exothermic reaction and generate high grade heat (e.g., about 210°C to 310°C, about 230°C to 290°C, or about 250°C to 270°C) is coupled to a first heat exchanger. The first heat exchanger is coupled to a reboiler in the integrated chemical separation apparatus that requires high grade heat (e.g., typically about 170°C to 180°C). By way of example, such a reboiler requiring high grade heat can be the reboiler of the third column in the three-column apparatus, or the first reboiler of the second column in the side reboiler apparatus. In any case, such a configuration meets the need for providing high grade heat to the integrated separation apparatus. Downstream of the first heat exchanger is a second heat exchanger, which can handle the same material stream as the first heat exchanger, but with the high grade heat extracted from the process stream. The second heat exchanger is coupled to a low temperature window in the integrated chemical separation apparatus (e.g., the reboiler of the first column in the three-column apparatus, or the second reboiler of the second column in the side reboiler apparatus) to provide low grade heat (e.g., a temperature of about 120°C to about 135°C) in the integrated chemical separation apparatus, where such low grade heat can be used to provide at least a portion of the heat required. This configuration identifies a low temperature window that can provide such heat, and uses low grade heat to meet such a need. By integrating the chemical synthesis apparatus with the chemical separation apparatus that can utilize low grade heat, the integrated apparatus can significantly reduce the work load, e.g., from about 4.2 megajoules per kilogram to zero or near zero (e.g., less than 2 megajoules per kilogram, less than 1 megajoule per kilogram, less than 0.5 megajoules per kilogram, or less than 0.1 megajoules per kilogram) for producing high purity methanol.

[0016] In certain embodiments, heat from the cooperating chemical synthesis apparatus can be delivered to a reboiler of the chemical separation apparatus by a direct process heating system, where the hot gas or other fluid produced by the reactor can be directly connected to the reboiler of the chemical separation apparatus.

[0017] In certain embodiments, heat from the cooperating chemical synthesis apparatus can be delivered to a reboiler of the chemical separation apparatus by a system having one or more heating medium loops, where the hot gas or other fluid produced by the reactor can be connected to such a heating medium loop, which is further connected to the reboiler of the chemical separation apparatus to provide heat thereto.

[0018] Further, some chemical separation facilities also seek to reduce their carbon footprint by using renewable energy sources rather than burning fossil fuels to obtain the required heat or power. Further, in some facilities, obtaining usable steam as a heat source can be challenging. The embodiments described herein can reduce or eliminate the need for chemical separation facilities to use steam as a heat source and facilitate electrification of chemical separation facilities. Some additional embodiments are described below that electrify exemplary chemical separation facilities, thereby reducing or eliminating the necessity of using steam as a heat source.

[0019] In one exemplary embodiment, a chemical separation facility designed to use electricity as a power source, reducing or eliminating the necessity of using steam as a heat source, includes a first column configured to receive a chemical process stream, the first column including at least one condensing unit, for example at a top end portion of the first column, and at least one reboiler; a second column for receiving a bottom fraction from the first column and including at least one condensing unit, for example at a top end portion of the second column, and at least one reboiler; a heat exchanger configured to transfer heat from the condensing 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.

[0020] In certain embodiments, the heat source can be a hot oil circuit.

[0021] In certain embodiments, the heat source includes an electric reboiler, wherein the reboiler of the second column further includes an electric coil configured to supply heat to the reboiler.

[0022] In certain embodiments, the heat source includes an electrically heated media circuit including a pipe connected to the reboiler of the second column, a pump, and an electric heater.

[0023] In certain embodiments, the heat source includes a heat pump including a pipe connected to the reboiler of the second column, a compressor, and an expansion valve.

[0024] It can be appreciated that the embodiments described herein are not limited to methanol purification processes and can be used in other various chemical processes that require or desire improved separation of products from process streams. Specific methods, embodiments, and variations of the system are described in more detail in the detailed description below. Further, the heat generating portion of such a facility is not limited to embodiments of the heat generating portion of a methanol synthesis process. A variety of chemical synthesis processes based on exothermic chemical reactions (e.g., exothermic) can be used.

[0025] As a further example, an exemplary chemical separation apparatus can include a first column, a second column, and a third column, wherein the first column is configured to receive a chemical process stream and includes at least one associated condensing unit (e.g., located at a top portion of the first column) and at least one reboiler configured to receive low grade heat from a low grade heat source. The second column can be configured to receive at least a portion of a bottom condensed fraction from the first column and includes at least one associated condensing unit (e.g., located at a top portion of the second column) and at least one reboiler configured to receive heat from a top fraction of the third column. The third column can be configured to receive at least a portion of a bottom condensed fraction from the second column and includes at least one associated condensing unit (e.g., located at a top portion of the third column) and at least one reboiler configured to receive high grade heat from a high grade heat source.

[0026] In any of the described embodiments, the first column can further include at least one stripping unit located at a top portion of the first column.

[0027] In any of the described embodiments, the chemical process stream can include crude methanol.

[0028] In any of the described embodiments, the first column can produce about 25% to about 40% of purified methanol produced by the chemical separation apparatus.

[0029] In any of the described embodiments, the second column can produce about 30% to about 50% of purified methanol produced by the chemical separation apparatus.

[0030] In any of the described embodiments, the third column can produce about 20% to about 30% of purified methanol produced by the chemical separation apparatus.

[0031] In any of the described embodiments, the first column can be a low pressure column.

[0032] In any of the described embodiments, the second column can be a low pressure column.

[0033] In any of the described embodiments, the third column can be a medium pressure column (e.g., having a working pressure higher than that of the first and / or second column).

[0034] In any of the described embodiments, the high grade heat source can be a hot gas stream or other hot fluid stream produced by a chemical synthesis apparatus.

[0035] In any of the described embodiments, the low grade heat source can be a hot gas stream or other hot fluid stream produced by a chemical synthesis apparatus, wherein any high grade heat originally present in the hot gas stream or other hot fluid stream has at least partially been depleted.

[0036] In any of the described embodiments, the heating medium circuit can transfer high grade heat from a high grade heat source to at least one reboiler of the third column.

[0037] In any of the described embodiments, the heating medium circuit can transfer low grade heat from a low grade heat source to at least one reboiler of the first column.

[0038] In any of the described embodiments, the low grade heat source from which heat can be recovered can be a hot wastewater stream.

[0039] Another exemplary embodiment is directed to a heat integrated system of a chemical synthesis plant producing low grade heat and high grade heat from an exothermic reaction and any of the chemical separation plants described herein. The system can include a reactor for performing a chemical synthesis configured to produce a process stream, a first heat exchanger configured to transfer high grade heat from the process stream to a reboiler of a third column, and a second heat exchanger disposed downstream of the first heat exchanger and configured to transfer remaining low grade heat from the process stream to a reboiler of a first column.

[0040] Another exemplary embodiment relates to a chemical separation plant including a first column configured to receive a chemical process stream and including at least one condensing unit (e.g., located at a top portion of the first column) and at least one reboiler. A second column is also provided, configured to receive at least a portion of a bottom condensed fraction from the first column and including at least one condensing unit (e.g., located at a top portion of the second column), a first reboiler associated with a bottom fraction of the second column, and a second reboiler associated with an intermediate fraction of the second column. A plurality of heat exchangers are also provided, wherein a first heat exchanger is configured to transfer a high grade heat source to the first reboiler of the second column, a second heat exchanger is configured to transfer a low grade heat source to the second reboiler of the second column, and a third heat exchanger is configured to transfer heat from a top fraction produced by the second column to at least one reboiler of the first column.

[0041] In any of the described embodiments, the first column can further include at least one stripping unit located at a top portion of the first column.

[0042] In any of the described embodiments, the chemical process stream can include crude methanol.

[0043] In any of the described embodiments, the first column can be a low pressure column.

[0044] In any of the described embodiments, the second column can be a medium pressure column (e.g., operating at a higher pressure than the first column).

[0045] Another example embodiment is directed to a heat integrated system of a chemical synthesis apparatus that produces low grade heat and high grade heat from an exothermic reaction and any of the chemical separation apparatuses described herein. The system can include a reactor for performing a chemical synthesis configured to produce 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 disposed downstream of the first heat exchanger and configured to transfer remaining low grade heat from the process stream to a second reboiler of the second column.

[0046] Another example embodiment is directed to a chemical separation apparatus including a first column configured to receive a chemical process stream and including at least one condensing unit (e.g., located at a top portion of the first column) and at least one reboiler. A second column is also provided that is configured to receive at least a portion of a bottom condensed fraction from the first column and includes at least one condensing unit (e.g., located at a top portion of the second column) and at least one reboiler. A heat exchanger is also provided that is configured to transfer heat from a top fraction produced by the second column to the at least one reboiler of the first column. An electrical heat source can also be provided that is configured to provide heat to the at least one reboiler of the second column.

[0047] In any of the described embodiments, the electrical heat source can include a hot oil loop including piping connected to the at least one reboiler of the second column, a pump, and an electrical heater.

[0048] In any of the described embodiments, the electrical heat source can include an additional reboiler that also includes an internal electrical heater.

[0049] In any of the described embodiments, the electrical heat source can include a heating medium loop including piping connected to the at least one reboiler of the second column, a pump, and an electrical heater.

[0050] In any of the described embodiments, the electrical heat source can include a heat pump including piping connected to the at least one reboiler of the second column, a compressor, and an expansion valve.

[0051] In any of the described embodiments, the electrical heat source can not include or use steam.

[0052] In any of the described embodiments, the chemical separation apparatus can be a methanol distillation apparatus.

[0053] In any of the described embodiments, the first column can further include at least one stripping unit located at a top portion of the first column.

[0054] These and other features, aspects, and advantages of the present disclosure can become evident to those skilled in the art from the following description, the accompanying claims, and the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1A An exemplary chemical separation apparatus is schematically shown, designed to utilize low grade heat using a three column design and direct process heating.

[0056] Figure 1B An exemplary chemical separation apparatus is schematically shown, designed to utilize low grade heat using a three column design and direct process heating. Figure 1A

[0057] An exemplary chemical separation apparatus is schematically shown, designed to utilize low grade heat using a three column design and direct process heating. Figure 2

[0058] An exemplary chemical separation apparatus is schematically shown, designed to utilize low grade heat using a side reboiler design. Figure 3A Figure 1A A system is schematically shown integrating the chemical separation apparatus shown in

[0059] Figure 3B Figure 1B A system is schematically shown integrating the chemical separation apparatus shown in

[0060] Figure 3C.1 , 3C.2 and 3C.3 schematically show how the heat of a methanol loop or other chemical synthesis can be directly transferred to the purification section of the system.

[0061] Figure 4A A system is schematically shown integrating the chemical separation apparatus shown in Figure 2

[0062] Figure 4B and Figure 4C schematically show systems similar to Figure 2 and Figure 4A but where a heat pump is employed to boost the low grade heat without requiring changes to the heating medium loop.

[0063] Figure 5 A chemical separation apparatus is schematically shown utilizing steam to power the chemical separation process.

[0064] Figure 6 A chemical separation apparatus is schematically shown utilizing a hot oil loop to provide heat to the chemical separation process.

[0065] Figure 7 A chemical separation apparatus is schematically shown utilizing an electric reboiler to provide heat to the chemical separation process.

[0066] ​​​Figure 8 A chemical separation apparatus is schematically shown utilizing an electrically heated media loop to provide heat for a chemical separation process.

[0067] Figure 9A and 9B A chemical separation apparatus is schematically shown utilizing a heat pump to provide heat for a chemical separation process. DETAILED DESCRIPTION

[0068] Various embodiments of the present disclosure can be better understood with reference to the following description and drawings, in which like reference numerals designate like elements.

[0069] While various modifications to the present disclosure and variations can be made, certain exemplary embodiments are shown in the drawings and will be described in more detail herein. It is understood that the disclosure is not limited to the embodiments disclosed, but is to be accorded the broadest scope permissible by the appended claims, where any and all embodiments falling within the scope of the claims are included.

[0070] It should be understood that no term or expression has been introduced to limit the meaning or to imply anything other than the plain or ordinary meaning thereof.

[0071] It is readily understood that the terms "comprise", "comprising", "include", "including" or other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0072] All heat exchangers described herein can be any suitable configuration of heat exchanger, having any suitable properties, and capable of operating in any suitable manner. By way of non-limiting example, any given heat exchanger can be a parallel flow heat exchanger, a counterflow heat exchanger, a finned or unfinned tube heat exchanger, a shell-and-tube heat exchanger, a U-tube heat exchanger, a single-pass straight heat exchanger, a double-pass straight heat exchanger, a plate or frame heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, or otherwise.

[0073] As a general term, "heat integration" is used to refer to any process by which heat is introduced from one process or system to another. Heat integration described in embodiments herein can be internal, i.e., within one independent system or process, or external, i.e., heat is introduced from one independent system or process to another independent process or system. By independent, it is meant that the system or process can (and typically will) be carried out independently of other systems or processes, and without regard for or integration with other systems or processes (e.g., there need not be an exchange of material streams between such processes).

[0074] While the carbon dioxide and hydrogen (e.g., from water electrolysis) to liquid (ETL) conversion of emissions to methanol device is primarily described in this embodiment as a device that can benefit from the described configuration, it is understood that other devices featuring exothermic chemical reactions (so that there is waste heat available) can also be suitable candidates. For example, other types of chemical synthesis devices that perform exothermic reactions as part of the product synthesis, particularly those that employ a flue gas CO2 stream as a reactant material used in the product synthesis, can be suitable candidates for the thermal integration described herein.

[0075] Also, in this embodiment, the chemical distillation device that separates high purity distilled methanol (e.g., about 99% pure) from a crude methanol process stream is primarily described as a device that can benefit from the described configuration. Nonetheless, it is understood that other chemicals, including other alcohols or other chemical materials that can need to be purified and / or separated, can also benefit from the described configuration.

[0076] Low grade heat, as used herein, refers to heat that can generally be considered waste heat, or heat that has limited or no utility for a particular process. High grade heat, as used herein, refers to a heat source that is of a higher temperature and is considered useful for heating a particular heat stream in a particular process. For example, a low grade heat source can refer to a heat source that is at a temperature of less than about 150 °C, while a high grade heat source can refer to a heat source that is at a temperature of greater than about 150 °C.

[0077] The term "low temperature window," as used herein, refers to a step in a given overall process (e.g., methanol purification) that is identified as being able to utilize low grade heat sources to provide the required heat. Such a low temperature window is characterized by a lower temperature and a lower quality energy requirement, as opposed to a process step that requires a high temperature (higher quality energy) input.

[0078] It is beneficial to integrate available heat sources and heat requirements of a process, particularly where a low temperature window can be identified or opened, where low grade heat can be used, as it improves the overall efficiency of energy usage, e.g., reducing the external heat requirement for the chemical separation portion of the process, while also reducing the cooling water requirement for the ETL or other chemical synthesis portion of the process. These benefits can be achieved simultaneously, as both high grade and low grade heat from the ETL device or other chemical synthesis device can be used for the reboiler of the chemical separation device, providing the necessary heat for the required purification or separation process, while reducing the requirement for externally supplied heat. For example, methanol purification is a costly process, and the production of methanol typically requires about 4.2 megajoules per kilogram of energy. By the described thermal integration configuration, the thermal integration process described herein can significantly reduce the operating load, e.g., it is possible to significantly reduce the typical requirement of about 4.2 megajoules per kilogram for the production of high purity methanol.

[0079] Further, by utilizing the high grade heat generated by the methanol synthesis reactor (or other similar exothermic reactor) and the low grade heat otherwise vented to the atmosphere or other cooling system, the embodiments can enable the chemical separation plant to operate entirely on the heat generated by the associated chemical synthesis plant (e.g., the methanol synthesis plant). These embodiments can replace the need for steam that is typically used to power the chemical separation plant. Thus, the embodiments are particularly useful for plants that can not have ready access to steam or that seek to reduce their carbon footprint, as the generation of steam typically requires a significant fossil fuel input.

[0080] Figure 1A An exemplary operating scheme for an exemplary chemical separation plant 100 that separates a process stream 113 (e.g., a process stream comprising crude methanol) through a first column 101, a second column 105, and a third column 108 is shown. Column 101 can be configured to receive process stream 113 through a side inlet. Column 101 further includes a reboiler 102 (e.g., associated with a bottom fraction of column 101) and a condensation unit 103 (associated with a top fraction of column 101). At least a portion of the bottom fraction of column 101 is sent to 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 plant) through stream 111a. This low grade heat is sufficient to reboil the circulating bottoms stream. The heated process stream 113a is returned to column 101, where it forms a vapor fraction and a bottom condensed fraction. The vapor fraction is collected by condensation unit 103, while the bottom condensed fraction settles to the bottom of first column 101, with a portion flowing to column 105 and another portion being recycled through reboiler 102. Condensation unit 103 can be connected to a stripping unit 104, which is used to remove dissolved gases from the condensed vapor fraction, producing high purity distilled methanol 114, which is sent to storage or other desired use. An example of a suitable stripping unit that can be used in the embodiments described herein is described in U.S. Patent 10,960,349, issued to the present applicant on March 30, 2021, which is incorporated by reference herein in its entirety. Any entrained gases (including methanol) contained in the stripping gas exiting stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas.

[0081] In an exemplary embodiment, column 101 can produce about 35%, e.g., 25% to 40%, of the high purity distilled methanol 114 produced by chemical separation plant 100.

[0082] In certain embodiments, column 101 can be a low pressure column, e.g., operating at 0 to about 0.5 bar (gauge).

[0083] Column 105 is configured to receive at least a portion of the bottoms condensed fraction from column 101, for example through a side inlet as shown. Column 105 also includes a reboiler 106 and a condensing unit 107. As shown, at least a portion of the bottoms output stream from column 105 is fed into reboiler 106. Reboiler 106 also includes a heat exchanger that is coupled to and receives heat from the overhead vapor fraction produced by column 108, wherein the heat (e.g., from the condensation of overhead fraction 108a) is transferred to a reboil stream 106a in reboiler 106 to reboil a recovered portion of the bottoms condensed fraction received from column 105. Reboiler 106 returns the heated stream 106a to column 105, which produces a vapor fraction and a bottoms condensed fraction within column 105. The vapor fraction from the top of column 105 is collected by condensing unit 107, which condenses it into high purity distilled methanol 114, which is sent to storage or other desired use, while the bottoms condensed fraction settles to the bottom of column 105 and is separated there, with a portion being recycled through reboiler 106 and another portion being sent to column 108 (preheated in heat exchanger 119 with hot waste water).

[0084] In certain embodiments, column 105 can produce about 40%, for example 30% to 50%, of the high purity distilled methanol 114 produced by chemical separation plant 100.

[0085] In certain embodiments, column 105 can be a low pressure column, for example, operating at 0 to about 0.5 bar (gauge).

[0086] Tower 108 is configured to receive at least a portion of the bottom condensed fraction from tower 105 through a side inlet. Tower 108 also includes a reboiler 109 and a condensing unit, such as a condensing unit associated with or integrated into reboiler 106. At least a portion of the bottom fraction from tower 108 is fed into 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 a methanol synthesis reactor of an ETL plant) through stream 110. The high grade heat delivered to reboiler 109 causes the bottom condensed fraction received from tower 108 to boil. Reboiler 109 delivers the heated condensed fraction back to tower 108, which produces a vapor fraction and a bottom fraction (mostly water) within third tower 108. The vapor fraction is used to provide heat to reboiler 106 through a heat exchanger, in which the condensation heat is transferred to reboiler 106, and the condensed high purity distillate methanol 114 is delivered to storage or other desired use. The water bottom fraction can be discharged from the plant as a waste stream 121, after which heat is recovered from the waste stream in heat exchangers 119 and 120. The purpose of heat exchangers 119 and 120 is to recover heat from the waste water of tower 108. The hot waste water is first used in heat exchanger 119 to preheat the feed provided to tower 108. Then, the partially cooled waste water is used in heat exchanger 120 to preheat the crude methanol feed stream entering tower 101. Preheating the feed streams to towers 108 and 101, respectively, can reduce the heat duty required by the separation plant, i.e., such heat integration can minimize the heat input requirement and help achieve zero or near zero duty distillation.

[0087] In certain embodiments, high grade heat stream 110 can provide sufficient energy to boil off all or substantially all of the remaining methanol in the bottom condensed fraction in stream 108b from tower 108, thereby recovering substantially all of the methanol in stream 114. In certain embodiments, tower 108 can produce about 25% of the high purity distillate methanol 114 produced by chemical separation plant 100, such as 20% to 30%.

[0088] In certain embodiments, tower 108 can be a medium pressure tower that operates at a higher operating pressure than towers 101 and 105. For example, third tower 108 can operate at a pressure of about 3 to about 3.5 bar (gauge pressure).

[0089] In some embodiments, stream 110 contains hot gas or hot fluid generated by an exothermic reaction, wherein stream 110 contains a high level of heat. For example, stream 110 may be cooled as it passes through reboiler 109, resulting in stream 111, which may contain a medium to low level of heat. This characteristic of utilizing a high level of heat to power the reboiler of the final column can be used in any of the embodiments described herein. Some embodiments may employ direct process heating, wherein streams 110 and / or 111 are fed directly into a specific reboiler or heat exchanger. Unlike heating medium loops, using direct process heating eliminates the need for a dedicated heating medium loop, thereby reducing the installation cost of a given system. Furthermore, using direct process heating can reduce the operating cost of a given system because it reduces or eliminates the need for various pumps. Nevertheless, embodiments incorporating closed heating medium loops are also feasible, examples of which will be described herein.

[0090] Figure 3A It shows a kind of Figure 1A A similar thermal integration system 300 is shown, but specifically integrated with a chemical synthesis reactor (such as an ETL unit). Such a system can be described as a zero-vapor distillation three-tower purification system that is directly heated. Regarding the chemical synthesis section of the unit, syngas feed 301 (such as 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 reactor 305, improving the energy efficiency of the process. The heat exchanger sequence (downstream of the reactor) 109-304-102-303 is configured to maximize the recovery of heat from the ETL unit to the methanol separation unit. The syngas feed is ultimately supplied to reactor 305 (e.g., a methanol conversion reactor), where an exothermic reaction occurs, converting the syngas feed 301 into crude methanol, producing a stream 110 containing a high level of heat. Stream 110 is fed into a heat exchanger associated with reboiler 109, where high-grade heat is transferred to reboiler 109, resulting in a cooling stream 111 containing medium and 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 into a heat exchanger associated with reboiler 102, where low-grade heat is transferred to reboiler 102, resulting in a cooling stream 112. Stream 112 is fed into heat exchanger 303 (preheating the synthesis gas stream before heat exchanger 304) and then into condenser 306. The stream exiting condenser 306 enters a gas collector 307, the top fraction 308 is discharged from the unit, and the bottom fraction (such as 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 include 60-70% methanol, 30-40% water (by weight), and small amounts (e.g., negligible) of reaction byproducts.

[0091] It is understood that in the exemplary chemical separation apparatus 100, reboiler 102 includes a cryogenic window. Reboiler 102 receives the process stream with the highest methanol concentration and lowest boiling point, thus requiring the lowest possible energy input temperature to separate most of the methanol from process stream 113. Therefore, stream 111a, which provides sufficient heat to reboiler 102 (rather than 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. Unlike reboiler 102, reboiler 109 (connected to the third column 108) receives the bottom condensate with the lowest total methanol concentration, and therefore the highest boiling point, requiring the highest possible input temperature to separate the last remaining methanol from process stream 108b. Therefore, a high-grade heat stream 110 is connected to reboiler 109 to maximize the utilization of the high-grade heat in stream 110. By providing three separation towers (e.g., instead of two) and separating steps that require less heat input from other steps that require more heat input, low-grade heat, which is usually considered waste heat, is utilized in the exemplary chemical separation apparatus described herein.

[0092] Figure 1B Another operating configuration of the chemical separation device 100' is shown, wherein the chemical separation device 100' also includes closed heating medium circuits 115 and 117. For example... Figure 1B As shown, 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 via a side inlet. Column 101 also includes a reboiler 102 and an associated condenser unit 103. At least a portion of the bottom distillate of column 101 is fed into reboiler 102, which is configured to receive low-grade heat from heating medium loop 117. Heating medium loop 117 utilizes multiple heat exchangers to transfer heat from a low-grade heat source (e.g., low-grade heat from an ETL device) to reboiler 102. Heating medium loop 117 also includes a pump 118 and a heating medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water (e.g., demineralized water), or any other heating medium fluid. The low-grade heat delivered to reboiler 102 can reboil 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 condenser unit 103, while the bottom condensate fraction settles to the bottom of the first column 101. The bottom condensate fraction is either fed to column 105 or recycled through reboiler 102. (As in...) Figure 1AAs described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas.

[0093] As described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas. Figure 1A As described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas.

[0094] As described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas. Figure 1A As described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas.

[0095] As described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas.

[0096] As described above in connection with FIG. 1, the condensing unit 103 can be connected to a stripping unit 104 for removing dissolved gases from the condensed vapor fraction to produce high purity distilled methanol 114 for storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting the stripping unit 104 can be sent to a second condenser 130 to condense any methanol product entrained in the stripping gas. Figure 1AThe column 108 is configured to receive the bottom condensed fraction from the column 105 through a side inlet. The column 108 also includes a reboiler 109. At least a portion of the bottom output from the column 108 is fed into the reboiler 109, which is configured to receive high grade heat from a heating medium circuit 115. The heating medium circuit 115 utilizes a plurality of heat exchangers to transfer heat from a high grade heat source (such as a methanol reforming reactor of an ETL plant) to the reboiler 109. The heating medium circuit 115 can further include a pump and a heating medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water, or other fluids. The high grade heat transferred to the reboiler 109 causes the bottom condensed fraction received from the column 108 to boil. The reboiler 109 feeds the heated condensed fraction back into the column 108, producing a vapor fraction and a bottom fraction (mostly water) within the third column 108. The top vapor fraction is transferred through a heat exchanger to the reboiler 106, where condensation heat is transferred to the reboiler 106, and the top fraction eventually condenses into high purity distilled methanol 114, which is fed to storage or other desired use. The bottom fraction settles at the bottom of the column 108, and the bottom condensed fraction is either recycled through the reboiler 109 or discharged from the plant as a waste stream 121, from which heat is recovered through heat exchangers 119 and 120.

[0097] In certain embodiments, the heating medium circuit 115 provides sufficient energy to boil off all or substantially all of the methanol remaining in the bottom condensed fraction received from the column 105, such that the resulting waste stream 121 is substantially free of methanol.

[0098] In certain embodiments, the column 108 can be a medium pressure column that produces about 25% of the high purity distilled methanol 114 produced by the chemical separation plant 100'.

[0099] Figure 3B It is shown that the column 108 is configured to receive the bottom condensed fraction from the column 105 through a side inlet. The column 108 also includes a reboiler 109. At least a portion of the bottom output from the column 108 is fed into the reboiler 109, which is configured to receive high grade heat from a heating medium circuit 115. The heating medium circuit 115 utilizes a plurality of heat exchangers to transfer heat from a high grade heat source (such as a methanol reforming reactor of an ETL plant) to the reboiler 109. The heating medium circuit 115 can further include a pump and a heating medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water, or other fluids. The high grade heat transferred to the reboiler 109 causes the bottom condensed fraction received from the column 108 to boil. The reboiler 109 feeds the heated condensed fraction back into the column 108, producing a vapor fraction and a bottom fraction (mostly water) within the third column 108. The top vapor fraction is transferred through a heat exchanger to the reboiler 106, where condensation heat is transferred to the reboiler 106, and the top fraction eventually condenses into high purity distilled methanol 114, which is fed to storage or other desired use. The bottom fraction settles at the bottom of the column 108, and the bottom condensed fraction is either recycled through the reboiler 109 or discharged from the plant as a waste stream 121, from which heat is recovered through heat exchangers 119 and 120. Figure 1BA similar heat integrated system 300' is shown, but specifically illustrating integration with a chemical synthesis reactor (e.g., an ETL unit). The system can be described as a zero vapor distillation three column purification system with two heating medium loops operating at different temperatures. With respect to the chemical synthesis portion of the unit, a synthesis gas feed 301 (e.g., H2 and CO2) can be fed to a compressor 302, then to heat exchangers 303, 304, then to a reactor 305 (e.g., a methanol conversion reactor) where an exothermic reaction occurs to convert the synthesis gas feed 301 to a crude methanol, producing a stream 110' containing high grade heat. The stream 110' is fed to a heat exchanger 309 configured to transfer the high grade heat to a heating medium loop 115, producing a cooled stream 111'. The stream 111' is fed to heat exchanger 304 (e.g., a final preheat before reactor 305), then to a heat exchanger 310 configured to transfer low grade heat to a heating medium loop 117, producing a cooled stream 112'. The stream 112' is fed to heat exchanger 303 (e.g., an initial preheat before reactor 305), then to a condenser 306. The stream exiting the condenser 306 is fed to a collection tank 307 where an overhead fraction 308 is purged and a bottoms fraction is fed as a process stream 113 (e.g., crude methanol) to a chemical separation unit.

[0100] The heating medium loop 115 utilizes a pump 116 to pump heating medium from the heat exchanger 309 to the reboiler 109 and to pump cooled heating medium from the reboiler 109 to the heat exchanger 309. Likewise, the heating medium loop 117 utilizes a pump 118 to pump heated heating medium from the heat exchanger 310 to the reboiler 102 and to pump cooled heating medium from the reboiler 102 to the heat exchanger 310.

[0101] The use of one or more heating medium loops can simplify the design of each reboiler, simplify the heating control system of each reboiler, and reduce the rating difference on the shell side of the heat exchangers associated with the reboilers to prevent fouling.

[0102] Figure 3C.1 、 3C.2 FIGS. 3A, 3B, and 3C schematically show the heat exchanger 309, the reboiler 109, and other associated facilities that transfer heat from the methanol loop or other chemical synthesis directly to the purification portion of the system in a normal heating medium configuration. While a heating medium system (standard schemes can be considered, where typically a heat exchanger 309 and a reboiler 109 are used to transfer heat from the methanol loop to the purification portion via a heat carrying fluid (e.g., demineralized water), alternative schemes can also be used where the heat can be transferred more directly. In Figure 3C.1 FIGS. 3A, 3B, and 3C schematically show the heat exchanger 309, the reboiler 109, and other associated facilities that transfer heat from the methanol loop or other chemical synthesis directly to the purification portion of the system in a normal heating medium configuration. While a heating medium system (standard schemes can be considered, where typically a heat exchanger 309 and a reboiler 109 are used to transfer heat from the methanol loop to the purification portion via a heat carrying fluid (e.g., demineralized water), alternative schemes can also be used where the heat can be transferred more directly. In Figure 3C.2 and 3C.3In one illustrative example, the inlet temperature to the reboiler 109' (on the methanol circuit side) can be about 260°C to about 280°C (stream 110), while the outlet temperature of the reboiler 109' can be about 190°C to about 210°C (stream 111). The water bottoms temperature (in the distillation section) can be its boiling point, e.g., about 150°C at the operating pressure. In this case, the necessary latent heat of vaporization for the required fluid for the mid-pressure column is provided by the reboiler within the mid-pressure column. This direct heating arrangement reduces the necessity of utilities for the facility, thereby reducing capital expenditure, since there is no need for an entire heating medium system (including all associated exchangers, piping, and pumps). All the heat required for the purification section can be provided by two reboilers. The first reboiler can utilize the heat of the methanol circuit, and the second reboiler can utilize steam (or electricity, depending on the configuration). Such a heat recovery arrangement can minimize the consumption of external utilities (steam or electricity) during normal operation. Such a configuration is described herein.

[0103] Figure 2 Another configuration is shown, i.e., employing two separate columns, where the last column includes a side reboiler, rather than a three-column configuration as shown in Figures 1A-1B and Figures 3A-3B . Figure 2 An example operating scheme for such an example chemical separation apparatus 200 is shown, which separates a process stream 113 through a first column 201 and a second column 205. The column 201 is configured to receive the process stream 113 (e.g., crude methanol) through a side inlet. The column 201 also includes a reboiler 202 and an associated condensing unit 203. The reboiler 202 also includes a heat exchanger that is coupled to an overhead vapor fraction from the column 205, where the condensation heat from the overhead fraction from the column 205 is transferred to the reboiler 202 and used to boil a bottoms portion of the column 201 through the reboiler 202, thereby creating an overhead vapor fraction and a bottoms condensed fraction within the column 201. The bottoms condensed fraction settles to the bottom of the column 201, which is either recycled through the reboiler 202 or sent to the column 205 (preheated with hot waste water in heat exchanger 211). The overhead fraction is collected by the condensing unit 203. The condensing unit 203 is optionally coupled to a stripping unit 204, which is used to remove dissolved gases from the overhead fraction, resulting in a high purity distilled methanol 114 that is sent to storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas that exits the stripping unit 204 can be sent to a second condenser 230 to condense any methanol product entrained in the stripping gas.

[0104] In certain embodiments, the column 201 can be a low pressure column.

[0105] Tower 205 is configured to receive the bottom condensed fraction from tower 201 through a side inlet. Tower 205 also includes a first reboiler 206, a second reboiler 207, and associated condensing units (e.g., in-line with reboiler 202). The bottom fraction of tower 205 is fed into reboiler 206, which is configured to receive high grade heat, such as from a heat medium loop 208. Heat medium loop 208 utilizes a plurality of heat exchangers to transfer heat from a high grade heat source (such as a methanol reforming reactor of an ETL plant) to reboiler 206. Heat medium loop 208 also includes a pump 211 (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. While a closed heat medium loop is shown in the figure, it is understood that a direct heating configuration, such as shown in Figure 4A and Figure 1A and Figure 3A may also be used. The high grade heat delivered to reboiler 206 heats the condensed fraction received from tower 205 to boiling. Reboiler 206 returns the heated condensed fraction to tower 205, which produces a top vapor fraction and a bottom fraction within tower 205. A side outlet of tower 205 is in communication with reboiler 207, which is configured to receive low grade heat (such as waste heat from an ETL plant) from an external heat source through stream 209, boiling an intermediate fraction moving upward through tower 205. Streams 209 and 210 can be either an open direct heating scheme (such as in Figure 4A or a closed heating loop. Reboiler 207 returns the heated intermediate fraction to an intermediate portion of tower 205 (hence, reboiler 207 is referred to as a "side reboiler"), which also helps to form a top vapor fraction and a bottom fraction within tower 205. The top vapor fraction is fed into reboiler 202, where condensation heat is transferred to reboiler 202, and the top fraction is eventually condensed into high purity distilled methanol 114, which is sent to storage or other desired uses. The bottom fraction settles to the bottom of tower 205, where the bottom fraction is either recycled through reboiler 206 or discharged from the plant as a waste stream 221, after which heat is recovered from the waste stream in heat exchangers 211 and 212.

[0106] In some embodiments, tower 205 can be a medium pressure tower.

[0107] Figure 4A is shown in Figure 2A similar heat integrated system 400 is shown, but specifically illustrating integration with a chemical synthesis reactor (e.g., an ETL apparatus). This system can be described as a zero vapor distillation purification system with a side reboiler. With respect to the chemical synthesis portion of the apparatus, a synthesis gas feed 301 (e.g., H2and CO2) can be fed into a compressor 302, then through heat exchangers 303, 304 to a methanol conversion reactor 305, where an exothermic reaction occurs to convert the synthesis gas feed 301 into a crude methanol, producing a stream 110' containing high grade heat. Stream 110' is fed into heat exchanger 309, which is configured to deliver the high grade heat to heating medium circuit 208, thereby producing a cooled stream 111'. Stream 111' is passed through heat exchanger 304, then fed into a heat exchanger associated with reboiler 207, delivering low grade heat to reboiler 207, thereby producing a cooled stream 112''. Stream 112'' is fed into heat exchanger 303, then into condenser 306. The stream exiting condenser 306 is fed into a collection tank 307, where an overhead fraction 308 is purified, while a bottoms fraction is fed as process stream 113 (e.g., crude methanol) into a chemical separation apparatus.

[0108] Heating medium circuit 208 pumps heating medium from heat exchanger 309 to reboiler 206, and from reboiler 206 to heat exchanger 309, using pump 213. Although Figure 4A A direct heating configuration is shown with respect to delivering low grade heat to side reboiler 207, however it is understood that a closed heating circuit (e.g., similar to Figure 3B circuit 117) shown in FIG. 1 can alternatively be used.

[0109] It is understood that reboiler 207 (in connection with column 205) comprises a low temperature window in exemplary chemical separation apparatus 200. Reboiler 207 receives a liquid fraction drawn from an intermediate portion of column 205, which is at a lower temperature than the temperature of the fraction at the bottom of column 205. In one embodiment, the temperature at the intermediate portion of the column (where the intermediate fraction is drawn to side reboiler 207) is typically around 110°C to 120°C, while the temperature at the bottom of column 205 is typically between 145°C to 155°C. Thus, the low grade heat is sufficient to boil this portion of the cooler fraction. Accordingly, a stream 111'' that provides sufficient heat for reboiler 207, but not reboiler 206, is connected to side reboiler 207.

[0110] The heat integration systems described herein improve the overall energy efficiency of the plant. Specifically, by transferring both high grade and low grade heat to reboilers in the chemical separation plant, the effluent stream from the reactor 305 can be cooled, reducing the load required to cool the product effluent stream from the reactor, while also reducing the load required to power the reboilers for the chemical separation section of the plant. In certain embodiments, the total heat required to perform the chemical separation process in the chemical separation plants 100 and 200 is provided by the integrated ETL or other exothermic chemical synthesis plant by implementing the systems shown in FIGS. Figure 3A , 3B and 4A. In these embodiments, the need for steam as a heat source is replaced or completely eliminated. Further embodiments, such as the embodiments described below, describe alternative designs that can replace the need for steam as a heat source.

[0111] Figure 4B and Figure 4C schematically show systems similar to Figure 2 and Figure 4A , but with the addition of a heat pump to upgrade the low grade heat without changing the heating medium circuits of the systems shown in Figure 2 and 4A . For example, such systems can be described as dual column (split column) designs that incorporate a heat pump to upgrade the low grade heat. This approach is based on the Figure 4A (dual column - side reboiler concept), in which the previously mentioned side reboiler is moved from the mid-cut to the bottom cut, now becoming the "second reboiler", and the low grade heat is no longer directly utilized, but is upgraded to approximately the same temperature level as the first reboiler through a heat pump circuit (e.g., including an evaporator, compressor, condenser, and expansion valve). This adds a second reboiler that delivers a stream with a similar quality (temperature) to the stream delivered by the first reboiler (e.g., about 125°C to 175°C, about 135°C to 165°C, or about 145°C to 155°C). As a result of the heat pump, a low grade heat source can be used to provide part of the heat required in the distillation process, without the need to provide high grade heat to the entire feed stream, which would otherwise be sent to the column through the first reboiler. The use of the heat pump circuit can eliminate or reduce the use of inlet steam, while effectively utilizing the additional electrical power required to operate the compressor of the heat pump circuit. Figure 4B schematically shows such an exemplary chemical separation plant designed to utilize low grade heat by implementing a heat pump circuit that includes an evaporator, compressor, condenser (second reboiler), and expansion valve. Figure 4C schematically shows a system that integrates the chemical separation plant in Figure 4B with a methanol synthesis plant (e.g., an ETL plant). Such a system can be described as a zero steam distillation purification system with a side reboiler.

[0112] Those skilled in the art will appreciate that other heat pump schemes can also be used, as well as various temperature ranges, refrigerants or refrigerant mixtures, etc. The use of embodiments incorporating heat pumps can further enable the goal of providing "all-electric" equipment in various embodiments, as compared to direct electric-thermal. Heat pumps in which power is delivered to the compressor in a heat pump circuit have the potential for significant savings in operating costs as compared to direct electric-thermal, due to the thermodynamic advantage of moving heat as opposed to generating heat from electricity. Recent advances in high temperature heat pumps are applicable to the temperature levels considered herein, making such heat pumps particularly attractive.

[0113] Figure 5 An exemplary operating scheme for an exemplary chemical separation apparatus 500 is shown, which separates a process stream 113 (e.g., crude methanol) through a first column 501 and a second column 505. Column 501 is configured to receive process stream 113 through a side inlet. Column 501 also includes a reboiler 502 and associated condensing unit 503. The bottom fraction of column 501 is fed into reboiler 502. Reboiler 502 includes a heat exchanger that provides heat to the material passing through reboiler 502, which heat is provided by a top vapor fraction from second column 505, wherein the condensation heat from the top vapor fraction from column 505 is transferred to reboiler 502 and used to boil the column bottom stream 501b, producing a vapor fraction and a bottom condensed fraction within column 501. The top vapor fraction is collected by condensing unit 503, while the bottom condensed fraction settles to the bottom of column 501. A portion of the bottom condensed fraction enters column 505, while another portion is circulated to column 501 through reboiler 502. Condensing unit 503 is optionally connected to a stripping unit 504, which is used to remove dissolved gases in the condensed vapor fraction, producing high purity distilled methanol 114, which is sent to storage or other desired use. Any entrained gases (including methanol) contained in the stripping gas exiting stripping unit 504 can be sent to a second condenser 530 in order to condense any methanol product entrained in the stripping gas. In one embodiment, the stripping gas can include nitrogen, but can also include other gases.

[0114] In certain embodiments, column 501 can be a low pressure column.

[0115] Tower 505 is configured to receive a bottom condensed fraction from tower 501 through a side inlet. Tower 505 also includes a first reboiler (e.g., a heating medium reboiler) 506, a second reboiler (e.g., a steam reboiler) 511, and a condensing unit associated with or downstream of reboiler 502. The bottom fraction of tower 505 is fed into reboiler 506, which is configured to receive high grade heat from a heating medium circuit 507. Heating medium circuit 507 also includes a pump 508 and a heating medium, which can be any substance capable of transferring heat between heat exchangers, such as oil, water, or other fluids, for boiling the condensed fraction received from tower 505. Heating medium circuit 507 uses a heat exchanger 509 to transfer heat from a high grade heat source (e.g., a methanol reformer of an ETL apparatus) to the heating medium. Pump 508 circulates the heated heating medium to reboiler 506 and returns the cooled heating medium to heat exchanger 509. The high grade heat transferred to reboiler 506 can boil the condensed fraction received from tower 505. Reboiler 506 returns the heated condensed fraction to tower 505, which produces a top vapor fraction and a bottom fraction within tower 505. Another portion of the bottom fraction from tower 505 is fed into reboiler 511, which is configured to receive heat from a steam heating infrastructure 514 (e.g., a steam boiler, a steam condensing pump, and a steam condensing tank as illustrated), which is configured to boil, circulate, and deliver heated steam to reboiler 511. The heat transferred to reboiler 511 can boil the condensed fraction received from tower 505. Reboiler 511 returns the heated condensed fraction to tower 505 and causes a top vapor fraction and a bottom fraction to form within tower 505. The top vapor fraction is collected by a condensing unit associated with reboiler 502 (e.g., downstream of reboiler 502), where heat from the top vapor fraction stream is transferred to reboiler 502, and the top vapor fraction is condensed into high purity distilled methanol 114, which is sent to storage or other desired use. The bottom condensed fraction from tower 505 is either discharged as waste water or recycled through reboiler 506 and / or reboiler 511. Liquid can also be drawn from the bottom of tower 505 or from heat exchanger 506, but can be less convenient.

[0116] Figure 5The configuration shown shows liquid being fed to reboilers 506 and 511 separately (e.g., they are at a hydrostatic equilibrium, so liquid can flow back and forth between column 505, reboilers 506 and 511). In one embodiment, only vapor from the reboilers is fed back to column 505. Liquid is drawn from reboiler 511, and after heat recovery in heat exchangers 517 and 518, it is discharged as waste water. In other words, reboiler 506 boils the bottom of column 505. The vapor produced is fed to column 505. The remaining liquid is fed to reboiler 511. Vapor produced in reboiler 511 is fed to column 505. The remaining liquid that does not boil in reboiler 511 is discharged as waste water (after heat recovery in heat exchangers 517 and 518). Alternatively, both water and vapor from reboiler 506 can be fed back to column 505, and then liquid is separately fed to reboiler 511. Liquid and vapor from reboiler 511 are fed to column 505, and then liquid is ultimately drawn from the bottom of column 505, but this can not bring any additional benefit. Of course, other configurations are possible, i.e., water is drawn from reboiler 506 and discharged as waste water.

[0117] One example purpose of heat exchangers 517 and 518 is to recover heat from the water bottoms of column 505. For example, this configuration can be to feed the hot water bottoms of column 505 to heat exchanger 517, where heat is transferred from the hot water bottoms of column 505 to the cooler bottom condensate fraction from column 501. The hot bottom condensate fraction from heat exchanger 517 is then fed as feed to column 505.

[0118] Heat exchanger 518 receives the partially cooled water bottoms from heat exchanger 517 (originating from column 505) and transfers heat to the cold crude methanol in stream 113. The hot stream 113 is then fed as feed to column 501. This heat recovery reduces the amount of heat required to be provided to column 505 by heat exchangers 511 and 506.

[0119] Chemical separation plant 500 is a typical chemical separation plant that relies on steam-related infrastructure as a heat source. However, a reliable source of steam can be difficult to obtain, and / or can reduce carbon emission savings. Other embodiments described below replace the need for steam-related infrastructure and allow for integration of electrical power sources, including renewable sources.

[0120] Figure 6 An example operating scheme for example chemical separation plant 600, which is an electrified alternative to chemical separation plant 500, is shown. As Figure 6As shown, the chemical separation apparatus 600 replaces reboiler 511 and associated steam heating infrastructure 514 with reboiler 601, wherein reboiler 601 is configured to receive heat from hot oil circuit 602. Hot oil circuit 602 also includes pump 603 and electric heater 604, wherein electric heater 604 heats the oil in hot oil circuit 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, thereby promoting the formation of a top vapor fraction and a bottom fraction within column 505. In one embodiment, only vapor from reboiler 601 is fed into column 505. The liquid is drawn from reboiler 601 and discharged as wastewater after heat recovery in heat exchangers 517 and / or 518. The top vapor fraction is fed into reboiler 502, where the heat gained from this stream is transferred to reboiler 502, where the top fraction is condensed into high-purity distilled methanol 114, which is sent to a storage site or other desired use. The bottom condensate from column 505 is either discharged as wastewater or recycled through reboilers 506 and / or reboiler 601. Figure 6 It may only show the liquid drawn from reboiler 601, but if needed, liquid can also be drawn from column 505 or reboiler 506.

[0121] In some embodiments, heater 604 operates on electricity generated from renewable energy sources, thereby reducing the associated carbon footprint.

[0122] The chemical separation unit 600 uses an electrically heated hot oil circuit to replace the heating infrastructure that relies on steam as a heat source, thus eliminating the need for steam. Furthermore, since the heating element of the electric heater 604 does not come into direct contact with the contents of the reboiler 601, the unit 600 minimizes potential thermal degradation of the process flow 113.

[0123] Figure 7 An exemplary operating scheme for an exemplary chemical separation device 700 is shown, which is an electrified alternative to chemical separation device 500. (As...) Figure 7 As shown, the chemical separation unit 700 replaces reboiler 511 and the associated steam heating infrastructure 514 with reboiler 701, wherein reboiler 701 also includes an internal electric heater for boiling the condensate received from column 505. Reboiler 701 returns the heated condensate to column 505, thereby promoting the formation of a top vapor fraction and a bottom fraction within column 505. The top and bottom fractions are then combined with… Figures 5-6 The same process is used.

[0124] Chemical separation apparatus 700 eliminates the need for steam by replacing the heating infrastructure that relies on steam as a heat source with a reboiler that includes an internal electric heater. Due to its simple design and minimal infrastructure, chemical separation apparatus 700 can greatly reduce installation and maintenance costs.

[0125] Figure 8 An exemplary operating scheme for exemplary chemical separation apparatus 800, an electrified alternative to chemical separation apparatus 500, is shown. As shown, Figure 8 Chemical separation apparatus 800 eliminates reboiler 511 and the associated steam heating infrastructure 514 and adds an electric heater 801 to heating medium loop 507, where electric heater 801 provides additional heat to heating medium loop and reboiler 506.

[0126] By replacing the heating infrastructure that relies on steam as a heat source with an additional electric heater in the heating medium loop, chemical separation apparatus 800 can eliminate the need for steam. In this way, electrical energy can be used for the chemical separation process of chemical separation apparatus 800.

[0127] Figures 9A-9B Other exemplary operating schemes for exemplary chemical separation apparatus 900 and 900', electrified alternatives to chemical separation apparatus 500, are shown. As shown, Figures 9A-9B Chemical separation apparatus 900, 900' eliminates reboiler 511 and the associated steam heating infrastructure 514 and adds a (e.g., electric) compressor 901 to heating medium loop 507 (now used as a heat pump), where compressor 901 increases the pressure of the heating medium. Heat from loop gas cooler 509 is used to vaporize the heating medium, and optionally, the vaporized heating medium is supplemented with heat from electric heater 801 (shown for system 900) before it is elevated to a higher temperature in compressor 901, enabling its use in reboiler 506. Figure 9A Figure 9B System 900' is shown without electric heater 801, while Figure 9A System 900 is shown with such optional electric heater 801. Any fluid that is capable of efficiently absorbing and releasing heat when undergoing a repeated phase change (from liquid to gas or vice versa) can be used as the heating medium fluid in the heating medium loop. Figure 9B The configuration shown in FIG. 9 without such electric heater 801 can be more practical and simpler.

[0128] ​The chemical separation plant 900, 900' replaces the heating infrastructure that relies on steam as a heat source by adding an (e.g., electrical) compressor 901 and an expansion valve 902, thereby replacing the need for steam, allowing the heating medium circuit to function as a heat pump. In this way, electrical energy can be used for the chemical separation process of the chemical separation plant 900, 900'.

[0129] Features of the disclosed embodiments can be combined or arranged other than as specifically described herein, and the disclosure is intended to be taken in its broadest sense in view of the teachings provided herein. Similarly, features of the disclosed embodiments can provide independent advantages and can be implemented or used in other embodiments not expressly described in detail herein.

[0130] It should be understood that all of the teachings herein can not address a specific problem or advantage and that specific embodiments can address only one or a particular combination of the issues or advantages. Those of ordinary skill in the art will recognize that the system and method can be practiced with the specifically identified elements, or equivalents thereof, without one or without a combination of all of the benefits or advantages taught or suggested herein.

[0131] Those of ordinary skill in the art will recognize that the various features disclosed can be interchanged or combined. Other known equivalents of the features described herein can be mixed and matched with each other in a manner not specifically described herein, to produce yet further assemblies that come within the scope of the principles of the disclosure. Those of ordinary skill in the art will understand that the features can be applicable to other systems and processes. Accordingly, the disclosure and its embodiments and variations are not limited to a methanol synthesis process or a particular partner plant, but can be utilized by thermal integration between any exothermic chemical process that produces waste heat and any partner process that produces high value steam or other high value working fluid / heating medium.

[0132] While the disclosure describes certain exemplary embodiments and implementations of thermal integration, those of ordinary skill in the art will appreciate that the disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the disclosure and / or modifications that can occur to those of ordinary skill in the art based on the teachings of the disclosure and its principles and their equivalents. The disclosure should not be limited to the specific embodiments described herein, but should be given the broadest scope consistent with the principles and uses disclosed herein.

[0133] Furthermore, unless otherwise indicated, the numbers expressing quantities of ingredients, constituents, distances, or other measured or quantitative data in the specification and claims should be understood to be used to indicate approximations only and are used by way of example only to provide an understanding of the principles and concepts underlying the present disclosure. Unless otherwise stated, the use of the singular includes the plural, the use of "or" means "and / or", and the use of "and" means "and / or" unless the context clearly indicates otherwise. The use of "about" or "approximately" in connection with a range of values or a number of times means that the value or number of times is within 20%, within 10%, within 5%, within 1%, within 0.1%, or within 0.01% of the stated value or number of times. The use of the term "between" includes any of the recited endpoints. For example, "between 2 and 10" includes 2 and 10.

Claims

1. A chemical separation plant comprising a first column, a second column and a third column, wherein: the first column is configured to receive a chemical process stream, the first column comprising at least one condensation unit located at a top end portion of the first column, 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 a bottom condensed fraction from the first column, the second column comprising at least one condensation unit located at a top end portion of the second column, and at least one reboiler configured to receive heat from a top fraction of the third column; and the third column is configured to receive at least a portion of a bottom condensed fraction from the second column, the third column comprising at least one condensation unit located at a top end portion 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 apparatus of claim 1, wherein, the first column further comprises at least one stripping unit located at a top end portion of the first column.

3. The chemical separation apparatus of claim 1, wherein, the chemical process stream comprises a crude methanol.

4. The chemical separation apparatus of claim 3, wherein, the first column produces between 25% and 40% of the purified methanol produced by the chemical separation plant.

5. The chemical separation apparatus of claim 3, wherein, the second column produces between 30% and 50% of the purified methanol produced by the chemical separation plant.

6. The chemical separation apparatus of claim 3, wherein, the third column produces between 20% and 30% of the purified methanol produced by the chemical separation plant.

7. The chemical separation apparatus of claim 1, wherein, the first column is a low pressure column.

8. The chemical separation apparatus of claim 1, wherein, the second column is a low pressure column.

9. The chemical separation apparatus of claim 1, wherein, the third column is a medium pressure column.

10. The chemical separation apparatus of claim 1, wherein, the high grade heat source is a hot gas stream produced by a chemical synthesis plant.

11. The chemical separation apparatus of claim 1, wherein, the low grade heat source is a hot gas stream produced by a chemical synthesis plant, wherein any high grade heat originally present in the hot gas stream has at least partially been depleted.

12. The chemical separation apparatus of claim 10, wherein, high grade heat is transferred from the high grade heat source to the at least one reboiler of the third column by means of a heating medium circuit.

13. The chemical separation apparatus of claim 11, wherein, low grade heat is transferred from the low grade heat source to the at least one reboiler of the first column by means of a heating medium circuit.

14. The chemical separation apparatus of claim 11, wherein, the low grade heat source from which heat is recovered is a hot wastewater stream.

15. A system for heat integration for heat integrating a chemical synthesis plant producing low grade heat and high grade heat from an exothermic reaction and the chemical separation plant of claim 1, wherein, the system comprises: a reactor configured to perform a chemical synthesis, the reactor being configured to produce a process stream, a first heat exchanger configured to transfer high grade heat from the process stream to a reboiler of the third column, and a second heat exchanger arranged downstream of the first heat exchanger, the second heat exchanger being configured to transfer low grade heat remaining in the process stream to a reboiler of the first column.

16. A chemical separation plant comprising: a first column configured to receive a chemical process stream, wherein the first column comprises at least one first condensation unit located at a top end portion of the first column, and at least one reboiler; a second column configured to receive at least a portion of a bottom condensed fraction from the first column, wherein the second column comprises at least one condensation unit located at a top end portion of the second column, a first reboiler in communication with a bottom fraction of the second column, and a second reboiler in communication with a middle fraction of the second column; and a third column configured to receive at least a portion of a bottom condensed fraction from the second column. a plurality of heat exchangers, wherein a first heat exchanger is configured to transfer high grade heat to a first reboiler of the second column, a second heat exchanger is configured to transfer low grade heat to a second reboiler of the second column, and a third heat exchanger is configured to transfer heat from an overhead fraction produced by the second column to at least one reboiler of the first column.

17. The chemical separation apparatus of claim 16, wherein, The first column further comprises at least one stripping unit located at a top end portion of the first column.

18. The chemical separation apparatus of claim 16, wherein, The chemical process stream comprises a crude methanol.

19. The chemical separation apparatus of claim 16, wherein, The first column is a low pressure column.

20. The chemical separation apparatus of claim 16, wherein, The second column is a medium pressure column.

21. A system for heat integration for heat integrating a chemical synthesis plant producing low grade heat and high grade heat from an exothermic reaction and the chemical separation plant of claim 16, wherein, The system comprises: a reactor configured to produce a process stream, a first heat exchanger configured to transfer high grade heat from the process stream to a first reboiler of the second column, and a second heat exchanger disposed downstream of the first heat exchanger and configured to transfer remaining low grade heat from the process stream to a second reboiler of the second column.

22. A chemical separation apparatus, wherein, The chemical separation apparatus comprises: a first column configured to receive a chemical process stream, the first column comprising at least one condensation unit located at a top end portion of the first column, and at least one reboiler; a second column configured to receive at least a portion of a bottom condensed fraction from the first column, the second column comprising at least one condensation unit located at a top end portion of the second column, and at least one reboiler; a heat exchanger configured to transfer heat from an overhead 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.

23. The chemical separation apparatus of claim 22, wherein, The electric heat source comprises a hot oil circuit comprising a pipe, a pump and an electric heater connected to at least one reboiler of the second column.

24. The chemical separation apparatus of claim 22, wherein, The electric heat source comprises an additional reboiler further comprising an internal electric heater.

25. The chemical separation apparatus of claim 22, wherein, The electric heat source comprises a heating medium circuit comprising a pipe, a pump and an electric heater connected to at least one reboiler of the second column.

26. The chemical separation apparatus of claim 22, wherein, The electric heat source comprises a heat pump comprising a pipe, a compressor and an expansion valve connected to at least one reboiler of the second column.

27. The chemical separation apparatus of claim 22, wherein, The electric heat source does not comprise a steam.

28. The chemical separation apparatus of claim 22, wherein, The chemical separation apparatus is a methanol distillation apparatus.

29. The chemical separation apparatus of claim 22, wherein, The first column further comprises at least one stripping unit located at a top end portion of the first column.

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