Systems and processes for producing glycols

Abstract

A system and method for producing ethylene glycol are disclosed. An alkylene oxide and water are fed into a first reactor unit, and the alkylene oxide and water are subjected to first reaction conditions in the first reactor unit such that the effluent from the first reactor unit contains an alkylene glycol, unreacted alkylene oxide, and unreacted water. At least a portion of the unreacted alkylene oxide can be routed to a second reaction unit and subjected to reaction conditions sufficient to produce further alkylene glycols.

Description

Technical Field

[0001] This invention generally relates to systems and processes for producing diols. More specifically, this invention relates to systems and methods for hydrating alkyl oxidases to form diols. Even more specifically, this invention relates to systems and methods for controlling the ratio of monoethylene glycol to diethylene glycol when these products are produced from ethylene oxide and water. Background Technology

[0002] Glycols are very useful compounds. For example, monoethylene glycol (MEG) is used as an antifreeze and coolant in engines, and as an intermediate in the production of polyester fibers and polyethylene terephthalate (PET), which is used to produce plastic bottles. Diethylene glycol (DEG) can be used in the production of polyurethanes, plasticizers, and organic solvents. Triethylene glycol (TEG) is commonly used as a plasticizer and humectant. Polyethylene glycol (PEG) is used in perfumes, cosmetics, lubricants, and plasticizers.

[0003] Ethylene glycol can be produced in a long plug flow reactor via non-catalytic thermal hydration of ethylene oxide (EO). The products of this method typically include monoethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. Market demand for each of these glycols usually varies over time. Therefore, it is desirable to control the yield of each type of glycol during glycol production. However, manipulating the proportion of each glycol in the glycol produced using this conventional method is very challenging. Furthermore, a higher proportion of monoethylene glycol requires more water in the reaction system, which increases energy consumption in subsequent separation processes. In conclusion, while methods for producing ethylene glycol exist, improvements are still needed in this field, at least given the aforementioned drawbacks. Summary of the Invention

[0004] Solutions have been explored to at least some of the aforementioned problems associated with methods for producing ethylene glycol. The solution lies in a process for producing ethylene glycol through the thermal hydration of ethylene oxide in a system comprising at least two reactor units and a separation unit connected in series. As described below, embodiments of the invention can help provide a higher monoethylene glycol to diethylene glycol ratio. Additionally, embodiments of the invention can be configured to reduce the energy consumption required for ethylene glycol production by lowering the high water to ethylene oxide ratio in the feed stream, which is necessary in conventional ethylene glycol production systems.

[0005] In embodiments of the invention, the first reactor unit includes a plug flow reactor, and the second reactor unit includes a reactive distillation column that also serves as a separation unit. In this way, the effluent from the plug flow reactor fed into the reactive distillation column undergoes complete or near-complete ethylene oxide conversion. The degree of ethylene oxide conversion in the first reactor is selected optimally to achieve the highest monoethylene glycol to diethylene glycol ratio in the final product.

[0006] In an embodiment of the invention, the first reactor unit includes a plug flow reactor, and a distillation column is adapted to receive the effluent from the plug flow reactor, react it, and separate the effluent from the plug flow reactor. A second reactor unit includes a plug flow reactor adapted to react the bottom stream from the distillation column. In this way, the effluent from the first reactor unit can be fed into the distillation column and separated into a monoethylene glycol-rich stream with a high water-to-ethylene oxide ratio and an ethylene oxide-rich stream with a low water-to-ethylene oxide ratio (i.e., a lower water-to-ethylene oxide ratio than the monoethylene glycol-rich stream). The ethylene glycol-rich stream can then be fed into the second reactor to produce additional monoethylene glycol. This can be advantageous compared to conventional methods by increasing the monoethylene glycol to diethylene glycol ratio in the product stream. Additionally, in an embodiment of the invention, the ethylene oxide-rich stream separated from the effluent from the first reactor can be recycled back to the first reactor to produce additional ethylene glycol, or it can be sent for the production of pure ethylene oxide. Therefore, embodiments of the present invention can controllably increase the ratio of monoethylene glycol to diethylene glycol produced by the thermal hydration of ethylene oxide, thereby improving production efficiency and reducing the production cost of ethylene glycol. Thus, the method of the present invention provides a technical solution to at least some of the problems associated with currently available methods for producing ethylene glycol.

[0007] Embodiments of the present invention include a method for producing diols. The method includes feeding alkylene oxide and water into a first reactor unit, and subjecting the alkylene oxide and water in the first reactor unit to first reaction conditions such that the effluent from the first reactor unit comprises alkylene glycols, unreacted alkylene oxides, and unreacted water. The method further includes feeding at least a portion of the unreacted alkylene oxides into a second reaction unit, such as a reactive distillation unit, and subjecting the unreacted alkylene oxides in the second reactor unit to second reaction conditions sufficient to produce additional alkylene glycols. The degree of conversion of the alkylene oxides in the first reactor is selected optimally to achieve the highest monoalkylene glycol to dialkylene glycol ratio in the final product.

[0008] Embodiments of the present invention include a method for producing ethylene glycol. The method includes feeding ethylene oxide and water into a first reactor unit, and subjecting the ethylene oxide and water in the first reactor unit to first reaction conditions such that the effluent from the first reactor unit contains monoethylene glycol, unreacted ethylene oxide, and unreacted water. The method further includes feeding at least a portion of the unreacted ethylene oxide into a second reaction unit, and subjecting the unreacted ethylene oxide in the second reactor unit to second reaction conditions sufficient to produce additional monoethylene glycol.

[0009] Embodiments of the present invention include a method for producing ethylene glycol. The method includes feeding ethylene oxide and water into a first reactor. The method further includes subjecting the ethylene oxide and water to reaction conditions in the first reactor such that the effluent from the first reactor contains monoethylene glycol, unreacted ethylene oxide, and unreacted water. Preferably, the degree of ethylene oxide conversion in the first reactor is selected to achieve the highest possible monoethylene glycol to diethylene glycol ratio in the final product. The method further includes feeding the effluent from the first reactor into a reactive distillation column to completely convert ethylene oxide to ethylene glycol or at least 98 wt.% of ethylene oxide to ethylene glycol. According to embodiments of the invention, the method also involves using a reactive distillation column to separate the effluent from the first reactor into an overhead stream containing unreacted water and unreacted ethylene oxide (which is fed back to the reactive distillation unit as reflux) and a second stream containing unreacted water and diol. The second stream (bottom stream) may contain 11 wt.% to 25 wt.% monoethylene glycol, 0.8 wt.% to 3 wt.% diethylene glycol and 72 wt.% to 88 wt.% water.

[0010] Embodiments of the present invention include a method for producing ethylene glycol. The method includes feeding ethylene oxide and water into a first reactor. The method includes subjecting the ethylene oxide and water in the first reactor to reaction conditions sufficient to produce monoethylene glycol, such that the effluent from the first reactor contains unreacted water, unreacted ethylene oxide, and monoethylene glycol. The method further includes separating the effluent from the first reactor into a first stream generally comprising primarily unreacted water and unreacted ethylene oxide, and a second stream generally comprising primarily unreacted ethylene oxide, unreacted water, and monoethylene glycol. The method further includes feeding the second stream into a second reactor. The method further includes subjecting the second stream in the second reactor to reaction conditions sufficient to produce additional monoethylene glycol and converting more than 98 wt.%, preferably more than 99.9 wt.%, of the ethylene oxide flowing into the second reactor.

[0011] Embodiments of the present invention include a method for producing alkylene glycols. The method includes feeding alkylene oxides and water into a first reactor. The method further includes subjecting the alkylene oxides and water to reaction conditions in the first reactor such that the effluent from the first reactor contains monoalkylene glycols, unreacted alkylene oxides, and unreacted water. Preferably, the degree of ethylene oxide conversion in the first reactor is selected optimally to achieve the highest monoethylene glycol to diethylene glycol ratio in the final product. The method further includes feeding the effluent from the first reactor into a reactive distillation column to completely convert the alkylene oxides to alkylene glycols or at least 98 wt.% of the alkylene oxides to alkylene glycols. According to embodiments of the invention, the method also involves using a reactive distillation column for further separating the effluent from the first reactor into a first stream generally containing primarily unreacted water and unreacted alkylene oxides, and a second stream generally containing primarily unreacted alkylene oxides, unreacted water, and monoalkylene glycols.

[0012] Embodiments of the present invention include a method for producing alkylene glycols. The method includes feeding alkylene oxides and water into a first reactor. The method includes subjecting the alkylene oxides and water in the first reactor to reaction conditions sufficient to produce monoalkylene glycols, such that the effluent from the first reactor contains unreacted water, unreacted alkylene oxides, and monoethylene glycol. The method further includes separating the effluent from the first reactor into a first stream generally comprising unreacted water and unreacted alkylene oxides, and a second stream generally comprising unreacted alkylene oxides, unreacted water, and monoalkylene glycols. The method further includes feeding the second stream into a second reactor. The method further includes subjecting the second stream in the second reactor to reaction conditions sufficient to produce additional monoalkylene glycols and converting more than 98 wt.%, preferably more than 99.9 wt.%, of the alkylene oxides flowing into the second reactor.

[0013] The following includes definitions of various terms and phrases used throughout this specification.

[0014] The terms “about” or “approximately” are defined as close to what a person skilled in the art would understand. In one non-limiting embodiment, the term is defined as less than 10%, preferably less than 5%, more preferably less than 1%, and most preferably less than 0.5%.

[0015] The terms “wt.%”, “vol.%”, or “mol.%” refer to the weight percentage, volume percentage, or mole percentage of a component based on the total weight, volume, or number of moles of the material including the component. In a non-limiting example, 10 moles of a component in 100 moles of material is 10 mol.% of the component.

[0016] The term “substantially” and its variations are defined as including ranges of up to 10%, up to 5%, up to 1%, or up to 0.5%.

[0017] When used in the claims and / or this specification, the terms “suppress” or “reduce” or “prevent” or “avoid” or any variation thereof include any measurable reduction or complete suppression to achieve the desired result.

[0018] The term "effective" as used in this specification and / or claims means sufficient to achieve the desired, anticipated, or anticipated result.

[0019] When used in conjunction with the terms “comprising,” “including,” “containing,” or “having” in the claims or this specification, the use of the article “a” or “one” may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more”.

[0020] The words “comprising” (and any form of inclusion, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”), or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unlisted elements or steps of the method.

[0021] The process of the present invention may "comprise" the specific ingredients, components, compositions, etc. disclosed throughout the specification, "consistently constitute" or "composed of".

[0022] The term "major" as used in this specification and / or claims means greater than any one of 50 wt.%, 50 mol.%, and 50 vol.%. For example, "major" can include all values ​​and ranges from 50.1 wt.% to 100 wt.%, 50.1 mol.% to 100 mol.%, or 50.1 vol.% to 100 vol.%.

[0023] Other objects, features, and advantages of the invention will become apparent from the following drawings, detailed description, and embodiments. However, it should be understood that while the drawings, detailed description, and embodiments illustrate specific embodiments of the invention, they are given by way of illustration only and are not intended to be limiting. Furthermore, it is contemplated that variations and modifications within the spirit and scope of the invention will become apparent to those skilled in the art based on this detailed description. In other embodiments, features from a specific embodiment may be combined with features from other embodiments. For example, a feature from one embodiment may be combined with features from any other embodiment. In other embodiments, additional features may be added to the specific embodiments described herein. Attached Figure Description

[0024] For a more complete understanding, please now refer to the following description in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A schematic diagram of a system for producing ethylene glycol according to an embodiment of the present invention is shown;

[0026] Figure 2 A schematic diagram of a system for producing ethylene glycol according to an embodiment of the present invention is shown;

[0027] Figure 3 A schematic flow chart of a method for producing ethylene glycol according to an embodiment of the present invention is shown; and

[0028] Figure 4 A schematic flowchart of a method for producing ethylene glycol according to an embodiment of the present invention is shown. Detailed Implementation

[0029] Currently, ethylene glycol, including monoethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol, is produced in a plug flow reactor via the thermal hydration of ethylene oxide. Conventional methods can only increase the monoethylene glycol to diethylene glycol ratio by increasing the water-to-ethylene oxide ratio in the reactor, which increases the energy required for downstream separation. The present invention provides at least a solution to this problem. The solution presupposes a method for producing ethylene glycol via the thermal hydration of ethylene oxide in a system comprising, for example, one reactor and a reactive distillation column in series, or at least two reactors and distillation columns in series. For a system with a reactor and a reactive distillation column, the effluent from the reactor undergoes further conversion in the reactive distillation column, which can be operated under partial or complete reflux, and also separates the effluent in the reactive distillation column to produce (1) an ethylene oxide-rich, unreacted ethylene oxide overhead stream and (2) a bottom stream rich in monoethylene glycol. According to an embodiment of the invention, the ethylene oxide-rich overhead stream is fed back to the reactive distillation column after condensation. Ethylene oxide is substantially completely converted to ethylene glycol in a reactive distillation column, resulting in a higher monoethylene glycol to diethylene glycol ratio. For a system with two reactors and a distillation column, the effluent from the first reactor is separated into an ethylene oxide-rich stream with a low water-to-ethylene oxide ratio and a monoethylene glycol-rich stream with a high water-to-ethylene oxide ratio. The monoethylene glycol-rich stream is fed into the second reactor to completely convert ethylene oxide to glycol. The ethylene oxide-rich stream can be recycled back to the first reactor. Therefore, the yields of monoethylene glycol and diethylene glycol in the product stream are increased compared to conventional methods. These and other non-limiting aspects of the invention will be discussed in further detail in the following subsections.

[0030] A. A system used for the production of ethylene glycol

[0031] In embodiments of the invention, a system for producing ethylene glycol may include a first reactor unit and a second reactor unit that also performs a separation function. According to embodiments of the invention, the first reactor unit may be a reactor such as a plug flow reactor, and the second reactor unit may be a reactive distillation column for the continued thermal rehydration of ethylene oxide in the effluent of the first reactor unit, wherein the reactive distillation column also separates the effluent from the first reactor unit. Reference Figure 1 A schematic diagram of system 10 for producing ethylene glycol is shown.

[0032] According to an embodiment of the invention, system 10 includes reactor 101 configured to receive a feed stream 100 comprising primarily water and ethylene oxide. In an embodiment of the invention, reactor 101 comprises a plug flow reactor. Reactor 101 may be configured to subject water and ethylene oxide to reaction conditions sufficient to produce ethylene glycol. Ethylene glycol may include monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, or any combination thereof. In an embodiment of the invention, reactor 101 is substantially catalyst-free or catalyst-free. Therefore, the reaction conditions may be non-catalytic reaction conditions. Reactor 101 may be further configured to release an effluent stream 102 therefrom. Effluent stream 102 may contain unreacted water, unreacted ethylene oxide, monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, or any combination thereof. The degree of ethylene oxide conversion in the first reactor is selected optimally to achieve the highest monoethylene glycol to diethylene glycol ratio in the final product.

[0033] According to an embodiment of the invention, reactor 101 has a reaction residence time of 0.5 minutes to 8 minutes and all ranges and values ​​therebetween, including the following ranges: 0.5 minutes to 1.0 minute, 1.0 minute to 1.5 minutes, 1.5 minutes to 2.0 minutes, 2.0 minutes to 2.5 minutes, 2.5 minutes to 3.0 minutes, 3.0 minutes to 3.5 minutes, 3.5 minutes to 4.0 minutes, 4.0 minutes to 4.5 minutes, 4.5 minutes to 5.0 minutes, 5.0 minutes to 5.5 minutes, 5.5 minutes to 6.0 minutes, 6.0 minutes to 6.5 minutes, 6.5 minutes to 7.0 minutes, 7.0 minutes to 7.5 minutes, and 7.5 minutes to 8.0 minutes. Furthermore, the residence time of reactor 101 can be set to achieve the maximum MEG to DEG ratio of the system. Reactor 101 may include a heating mechanism suitable for heating water and ethylene oxide to a reaction temperature sufficient to produce ethylene glycol. The heating mechanism may include a heat exchanger located upstream of the inlet of reactor 101.

[0034] In an embodiment of the invention, the outlet of reactor 101 is in fluid communication with the inlet of reactive distillation column 103, such that effluent stream 102 flows from reactor 101 to reactive distillation column 103. According to an embodiment of the invention, reactive distillation column 103 is adapted to separate effluent stream 102 into multiple streams, including an overhead stream 107 and a bottom stream 106, a portion of which is fed back into the column as reflux 108, and a portion of which is some non-condensable gas (if present, stream 105). Further, in an embodiment of the invention, reactive distillation column 103 is adapted to provide reaction conditions such that unreacted ethylene oxide is converted into ethylene glycol. For example, reactive distillation column 103 may have an inlet for receiving aqueous stream 104 to react with the ethylene oxide in reactive distillation column 103. Further, reactive distillation column 103 may be operated to provide reaction conditions therein such that unreacted ethylene oxide in effluent stream 102 is converted into ethylene glycol. The overhead stream 107 may generally consist primarily of unreacted water and unreacted ethylene oxide. In an embodiment of the invention, the bottom stream 106 may generally consist primarily of unreacted water and monoethylene glycol, and this bottom stream is fed back into the column. Non-condensable gases (if present) may be separated as stream 105. The bottom stream 106 may further contain diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof.

[0035] In embodiments of the invention, a system for producing ethylene glycol may include two reactors connected in series for the thermal synthesis of ethylene oxide, and a separation unit for separating the effluent stream from the first reactor. (Reference) Figure 2 A schematic diagram of system 20 for producing ethylene glycol is shown.

[0036] According to an embodiment of the invention, system 20 includes a first reactor 201 configured to receive a feed stream 200 comprising primarily water and ethylene oxide. Alternatively to or supplementing to feed stream 200, water and ethylene oxide may be fed separately into the first reactor 201. In an embodiment of the invention, the first reactor 201 comprises a plug flow reactor. The first reactor 201 may be further configured to subject water and ethylene oxide to reaction conditions sufficient to produce ethylene glycol. Ethylene glycol may include monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof. In an embodiment of the invention, the first reactor 201 is substantially catalyst-free or catalyst-free. Therefore, the reaction conditions may be non-catalytic reaction conditions. The first reactor 201 may be further configured to release a first effluent stream 202 therefrom. The first effluent stream 202 may include unreacted water, unreacted ethylene oxide, monoethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof.

[0037] According to an embodiment of the invention, the first reactor 201 has a reaction residence time of 0.5 minutes to 8.0 minutes and all ranges and values ​​therebetween, including the following ranges: 0.5 minutes to 1.0 minute, 1.0 minutes to 1.5 minutes, 1.5 minutes to 2.0 minutes, 2.0 minutes to 2.5 minutes, 2.5 minutes to 3.0 minutes, 3.0 minutes to 3.5 minutes, 3.5 minutes to 4.0 minutes, 4.0 minutes to 4.5 minutes, 4.5 minutes to 5.0 minutes, 5.0 minutes to 5.5 minutes, 5.5 minutes to 6.0 minutes, 6.0 minutes to 6.5 minutes, 6.5 minutes to 7.0 minutes, 7.0 minutes to 7.5 minutes, and 7.5 minutes to 8.0 minutes. The first reactor 201 may include a heating mechanism suitable for heating water and ethylene oxide to a reaction temperature sufficient to produce ethylene glycol. The heating mechanism may include a heat exchanger located upstream of the inlet of the first reactor 201.

[0038] In an embodiment of the invention, the outlet of the first reactor 201 is in fluid communication with the inlet of the separation unit 203, such that the first effluent stream 202 flows from the first reactor 201 to the separation unit 203. According to an embodiment of the invention, the separation unit 203 is adapted to separate the first effluent stream 202 into multiple streams, including a first stream 204 and a second stream 205. The first stream 204 may generally consist primarily of unreacted water and unreacted ethylene oxide. The second stream 205 may generally consist of unreacted water, unreacted ethylene oxide, and monoethylene glycol. The second stream 205 may further contain diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof. In an embodiment of the invention, the separation unit 203 includes a distillation unit, a flash evaporator, or a combination thereof.

[0039] According to an embodiment of the invention, the first outlet of the separation unit 203 may be in fluid communication with the second reactor 206, such that the second stream 205 flows from the separation unit 203 to the second reactor 206. In an embodiment of the invention, the second reactor 206 is adapted to subject the second stream 205 to reaction conditions sufficient to produce additional ethylene glycol and form the product stream 207 flowing out of the second reactor 206. In an embodiment of the invention, the second reactor 206 may be a plug flow reactor. In an embodiment of the invention, the second reactor 206 has a reaction residence time sufficient for complete conversion of ethylene oxide. According to an embodiment of the invention, the second reactor 206 may be substantially identical to the first reactor 201.

[0040] According to an embodiment of the invention, the second outlet of the separation unit 203 may be in fluid communication with the inlet of the first reactor 201, such that the first stream 204 flows from the separation unit 203 to the first reactor 201. The first reactor 201 may be further adapted to react the unreacted ethylene oxide and unreacted water in the first stream 204 to form additional ethylene glycol.

[0041] B. Methods for producing ethylene glycol

[0042] A method for producing ethylene glycol via the thermal synthesis of ethylene oxide has been explored. Compared with conventional methods, this method can increase the ratio of monoethylene glycol to diethylene glycol in the product stream. Figure 3 As shown, an embodiment of the present invention includes a method 30 for producing ethylene glycol. Method 30 can be implemented by system 10, such as... Figure 1As shown. According to an embodiment of the invention, method 30 includes flowing a feed stream 100 comprising ethylene oxide and water into reactor 101, as shown in block 300. In an embodiment of the invention, feed stream 100 comprises a water-to-ethylene oxide ratio of 10 to 25 (in moles) and all ranges and values ​​therebetween, including the following ranges: 10 to 11, 11 to 12, 12 to 13, 13 to 14, 14 to 15, 15 to 16, 16 to 17, 17 to 18, 18 to 19, 19 to 20, 20 to 21, 21 to 22, 22 to 23, 23 to 24, and 24 to 25 (in moles). In an embodiment of the invention, the feed stream 100 may be at an inlet temperature of 120°C to 160°C and all ranges and values ​​therebetween, including the following ranges: 120°C to 121°C, 121°C to 122°C, 122°C to 123°C, 123°C to 124°C, 124°C to 125°C, 125°C to 126°C, 126°C to 127°C, 127°C to 128°C, 128°C to 129°C, 129°C to 130°C, 130°C to 131°C, 131°C to 132°C, 132°C to 133°C, 133°C to 134°C, 134°C to 135°C, 135°C to 136°C, 136°C to 130°C. 7℃, 137℃ to 138℃, 138℃ to 139℃, 139℃ to 140℃, 140℃ to 141℃, 141℃ to 142℃, 142℃ to 143℃, 143℃ to 144℃, 144℃ to 145℃, 145℃ to 146℃, 146℃ to 147℃, 147℃ to 148℃, 148℃ to 149℃, 149℃ to 150℃, 150℃ to 151℃, 151℃ to 152℃, 152℃ to 153℃, 153℃ to 154℃, 154℃ to 155℃, 155℃ to 156℃, 156℃ to 157℃, 157℃ to 158℃, 158℃ to 159℃, and 159℃ to 160℃. As an alternative to or supplement to feed stream 100, ethylene oxide and water can flow separately into reactor 101.

[0043] In an embodiment of the invention, as shown in block 301, method 30 includes subjecting ethylene oxide and water to reaction conditions in reactor 101 to induce a reaction between the ethylene oxide and water, such that the effluent stream 102 from reactor 101 contains monoethylene glycol, unreacted ethylene oxide, and unreacted water. According to an embodiment of the invention, the effluent stream 102 further comprises diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof. In an embodiment of the invention, the reaction conditions at block 301 include reactor inlet temperatures in the range of 120°C to 160°C and all ranges and values ​​therebetween, including the following ranges: 120°C to 122°C, 122°C to 124°C, 124°C to 126°C, 126°C to 128°C, 128°C to 130°C, 130°C to 132°C, 132°C to 134°C, 134°C to 136°C, 136°C to 138°C, 138°C to 140°C, 140°C to 142°C, 142°C to 144°C, 144°C to 146°C, 146°C to 148°C, 148°C to 150°C, 150°C to 152°C, 152°C to 154°C, 154°C to 156°C, 156°C to 158°C, and 158°C to 160°C. The reaction conditions at box 301 may include reaction pressures from 18 bar to 25 bar and all ranges and values ​​therebetween, including 19 bar, 20 bar, 21 bar, 22 bar, 23 bar, and 24 bar. The reaction conditions at box 301 may include residence times in reactor 101 from 0.5 minutes to 8.0 minutes and all ranges and values ​​therebetween, including the following ranges: 0.5 minutes to 1.0 minute, 1.0 minute to 1.5 minutes, 1.5 minutes to 2.0 minutes, 2.0 minutes to 2.5 minutes, 2.5 minutes to 3.0 minutes, 3.0 minutes to 3.5 minutes, 3.5 minutes to 4.0 minutes, 4.0 minutes to 4.5 minutes, 4.5 minutes to 5.0 minutes, 5.0 minutes to 5.5 minutes, 5.5 minutes to 6.0 minutes, 6.0 minutes to 6.5 minutes, 6.5 minutes to 7.0 minutes, 7.0 minutes to 7.5 minutes, and 7.5 minutes to 8.0 minutes. In an embodiment of the invention, reactor 101 operates with virtually no catalyst or no catalyst at all.

[0044] According to an embodiment of the invention, the effluent 102 comprises 8 wt.% to 15 wt.% monoethylene glycol, 1 wt.% to 8 wt.% ethylene oxide, and 75 wt.% to 89 wt.% water. In another embodiment of the invention, the effluent 102 may further comprise 0.5 wt.% to 2 wt.% diethylene glycol.

[0045] In an embodiment of the invention, as shown in block 302, method 30 further includes flowing the effluent stream 102 into a reactive distillation column 103. Embodiments of the invention may include flowing an aqueous stream 104 into the reactive distillation column 103, as shown in block 303 (optional). Furthermore, according to an embodiment of the invention, block 304 relates to providing reaction conditions in the reactive distillation column 103 such that unreacted ethylene oxide in the effluent stream 102 reacts with water from the aqueous stream 104 and / or unreacted water in the effluent stream to achieve complete or near-complete (e.g., 98 wt.%) conversion of ethylene oxide to ethylene glycol in the reactive distillation column 103. According to an embodiment of the present invention, the water stream 104 is in the temperature range of 125°C to 150°C and all ranges and values ​​therebetween (including the following ranges: 125°C to 126°C, 126°C to 127°C, 127°C to 128°C, 128°C to 129°C, 129°C to 130°C, 130°C to 131°C, 131°C to 132°C, 132°C to 133°C, 133°C to 134°C, 134°C to 135°C, 135°C to 136°C, 136°C to 137°C, 137°C to 138°C, 138°C to 139°C). The temperature ranges from 139°C to 140°C, 140°C to 141°C, 141°C to 142°C, 142°C to 143°C, 143°C to 144°C, 144°C to 145°C, 145°C to 146°C, 146°C to 147°C, 147°C to 148°C, 148°C to 149°C, and 149°C to 150°C, and the pressure ranges from 15 bar to 25 bar, and all ranges and values ​​in between (including the ranges of 16 bar, 17 bar, 18 bar, 19 bar, 20 bar, 21 bar, 22 bar, 23 bar, and 24 bar) are entered into the reactive distillation column 103. In an embodiment of the invention, the reactive distillation column 103 at block 305 further involves simultaneously separating the effluent stream 102 into an overhead stream 105 generally comprising unreacted water and unreacted ethylene oxide, and a bottom stream 106 generally comprising unreacted water and monoethylene glycol. In an embodiment of the invention, overhead streams 107 and 108 comprise 1 wt.% to 16 wt.% of unreacted ethylene oxide and 83 wt.% to 99 wt.% of unreacted water. Bottom stream 106 may comprise 72 wt.% to 88 wt.% of unreacted water, 0 wt.% to 0.1 wt.% of unreacted oxide, and 11 wt.% to 25 wt.% of monoethylene glycol. It should be noted that in embodiments of the invention, complete conversion of ethylene oxide is expected, resulting in 0 wt.% ethylene oxide in bottom stream 106. In embodiments of the invention, bottom stream 106 may further comprise diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof.

[0046] A method for producing ethylene glycol via the thermal synthesis of ethylene oxide has been explored. Compared with conventional methods, this method can increase the ratio of monoethylene glycol to diethylene glycol in the product stream. This method can further improve the conversion rate of ethylene oxide. Figure 4 As shown, an embodiment of the present invention includes a method 40 for producing ethylene glycol. Method 40 can be implemented by system 20, such as... Figure 2 As shown. According to an embodiment of the invention, as shown in block 400, method 40 includes flowing a feed stream 200 comprising ethylene oxide and water into a first reactor 201. In an embodiment of the invention, the feed stream 200 comprises a water-to-ethylene oxide ratio of 10 to 25 (in moles) and all ranges and values ​​therebetween, including: 10 to 11, 11 to 12, 12 to 13, 13 to 14, 14 to 15, 15 to 16, 16 to 17, 17 to 18, 18 to 19, 19 to 20, 20 to 21, 21 to 22, 22 to 23, 23 to 24, and 24 to 25 (in moles). In an embodiment of the invention, the feed stream 200 may be at a temperature of 120°C to 160°C and all ranges and values ​​therebetween before flowing into the first reactor 201, including the following ranges: 120°C to 121°C, 121°C to 122°C, 122°C to 123°C, 123°C to 124°C, 124°C to 125°C, 125°C to 126°C, 126°C to 127°C, 127°C to 128°C, 128°C to 129°C, 129°C to 130°C, 130°C to 131°C, 131°C to 132°C, 132°C to 133°C, 133°C to 134°C, 134°C to 135°C, 135°C to 136°C, 136°C to 130°C. 7℃, 137℃ to 138℃, 138℃ to 139℃, 139℃ to 140℃, 140℃ to 141℃, 141℃ to 142℃, 142℃ to 143℃, 143℃ to 144℃, 144℃ to 145℃, 145℃ to 146℃, 146℃ to 147℃, 147℃ to 148℃, 148℃ to 149℃, 149℃ to 150℃, 150℃ to 151℃, 151℃ to 152℃, 152℃ to 153℃, 153℃ to 154℃, 154℃ to 155℃, 155℃ to 156℃, 156℃ to 157℃, 157℃ to 158℃, 158℃ to 159℃, and 159℃ to 160℃. As an alternative to or supplement to feed stream 200, ethylene oxide and water can flow separately into the first reactor 201.

[0047] In an embodiment of the invention, as shown in block 401, method 40 includes subjecting ethylene oxide and water to reaction conditions in a first reactor 201 to induce a reaction between the ethylene oxide and water, such that a first effluent stream 202 from the first reactor 201 comprises monoethylene glycol, unreacted ethylene oxide, and unreacted water. According to an embodiment of the invention, the first effluent stream 202 further comprises diethylene glycol, triethylene glycol, polyethylene glycol, or combinations thereof. In an embodiment of the invention, the reactor inlet conditions at frame 401 include a reaction temperature in the range of 120°C to 160°C and all ranges and values ​​therebetween, including the following ranges: 120°C to 121°C, 121°C to 122°C, 122°C to 123°C, 123°C to 124°C, 124°C to 125°C, 125°C to 126°C, 126°C to 127°C, 127°C to 128°C, 128°C to 129°C, 129°C to 130°C, 130°C to 131°C, 131°C to 132°C, 132°C to 133°C, 133°C to 134°C, 134°C to 135°C, 135°C to 136°C, and 136°C to 137°C. 137℃ to 138℃, 138℃ to 139℃, 139℃ to 140℃, 140℃ to 141℃, 141℃ to 142℃, 142℃ to 143℃, 143℃ to 144℃, 144℃ to 145℃, 145℃ to 146℃, 146℃ to 147℃, 147℃ to 148℃, 148℃ to 149℃, 149℃ to 150℃, 150℃ to 151℃, 151℃ to 152℃, 152℃ to 153℃, 153℃ to 154℃, 154℃ to 155℃, 155℃ to 156℃, 156℃ to 157℃, 157℃ to 158℃, 158℃ to 159℃, and 159℃ to 160℃. The reaction conditions at box 401 may include reactor inlet pressures of 18 bar to 25 bar and all ranges and values ​​therebetween, including 19 bar, 20 bar, 21 bar, 22 bar, 23 bar and 24 bar. The reaction conditions at box 401 may include the residence time of the first reactor 201 in the range of 0.5 minutes to 8.0 minutes, and all ranges and values ​​therebetween, including 0.1 minutes to 0.5 minutes, 0.5 minutes to 1.0 minutes, 1.0 minutes to 1.5 minutes, 1.5 minutes to 2.0 minutes, 2.0 minutes to 2.5 minutes, 2.5 minutes to 3.0 minutes, 3.0 minutes to 3.5 minutes, and 3.5 minutes to 4.0 minutes, 4.0 minutes to 4.5 minutes, 4.5 minutes to 5.0 minutes, 5.0 minutes to 5.5 minutes, 5.5 minutes to 6.0 minutes, 6.0 minutes to 6.5 minutes, 6.5 minutes to 7.0 minutes, 7.0 minutes to 7.5 minutes, and 7.5 minutes to 8.0 minutes. In embodiments of the invention, the first reactor 201 is operated substantially without a catalyst or with no catalyst.

[0048] According to an embodiment of the invention, the separation of the first effluent stream 202 at frame 402 to produce a first stream 204 and a second stream 205 is carried out at a top boiling temperature range of 150°C to 180°C and a pressure range of 6 bar to 20 bar. In an embodiment of the invention, the first stream 204 comprises 69% to 93% water, 0.6% to 1.3% monoethylene glycol, and 6% to 29% ethylene oxide, and the second stream 205 comprises 77% to 87% water, 11% to 20% monoethylene glycol, 0.8% to 2.6% diethylene glycol, 0.04% to 0.4% triethylene glycol, and 0.0006% to 0.02% ethylene oxide.

[0049] According to an embodiment of the invention, as shown in block 403, method 40 further includes allowing a second stream 205 to flow into a second reactor 206. In an embodiment of the invention, as shown in block 404, method 40 includes subjecting the second stream 205 in the second reactor 206 to reaction conditions sufficient to produce additional monoethylene glycol and to convert greater than 98 wt.% of the ethylene oxide flowing into the second reactor 206. At block 404, the product stream 207 from the second reactor 206 may contain 11 wt.% to 25 wt.% monoethylene glycol and 0.8 wt.% to 3.0 wt.% diethylene glycol. In an embodiment of the invention, at block 404, all ethylene oxide flowing into the second reactor 206 is converted.

[0050] In an embodiment of the invention, the reaction conditions at box 404 include reactor inlet temperatures ranging from 160°C to 220°C and all ranges and values ​​therebetween, including the following ranges: 160°C to 162°C, 162°C to 164°C, 164°C to 166°C, 166°C to 168°C, 168°C to 170°C, 170°C to 172°C, 172°C to 174°C, 174°C to 176°C, 176°C to 178°C, 178°C to 180°C, 180°C to 182°C, and 182°C to 184°C. 184℃ to 186℃, 186℃ to 188℃, 188℃ to 190℃, 190℃ to 192℃, 192℃ to 194℃, 194℃ to 196℃, 196℃ to 198℃, 198℃ to 200℃, 200℃ to 202℃, 202℃ to 204℃, 204℃ to 206℃, 206℃ to 208℃, 208℃ to 210℃, 210℃ to 212℃, 212℃ to 214℃, 214℃ to 216℃, 216℃ to 218℃, and 218℃ to 220℃. The reaction conditions at box 404 may include reaction pressures of 10 bar to 20 bar and all ranges and values ​​therebetween, including 10 bar to 11 bar, 11 bar to 12 bar, 12 bar to 13 bar, 13 bar to 14 bar, 14 bar to 15 bar, 15 bar to 16 bar, 16 bar to 17 bar, 17 bar to 18 bar, 18 bar to 19 bar and 19 bar to 20 bar.

[0051] In an embodiment of the invention, the reaction conditions at block 404 include the residence time of the second reactor 206 for complete conversion of ethylene oxide. In an embodiment of the invention, the second reactor 206 operates with no catalyst or substantially no catalyst. According to an embodiment of the invention, as shown in block 405, method 40 further includes recovering and / or recycling at least a portion, preferably all, of the first stream 204, and diverting the recovered and / or recycled portion of the first stream 204 to the first reactor 201. As an alternative to or supplement to diverting the recovered and / or recycled portion of the first stream 204 to the first reactor 201, the recovered and / or recycled portion of the first stream 204 may flow to an ethylene oxide purification unit for ethylene oxide production.

[0052] As part of the disclosure of this invention, specific embodiments are included below. These embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art will readily recognize that parameters can be changed or modified to produce substantially the same results.

[0053] Example

[0054] (Ethylene glycol production simulation)

[0055] Simulations of ethylene glycol production using the system of the present invention were performed in Aspen PLUS. TM The platform is in operation. The feed to the first reactor contains only ethylene oxide (EO) and water.

[0056] Case A: Normal operation of a conventional system (PFR reactor) and... Figure 1 The diagram shows a comparison of the operation of a system comprising a plug flow reactor and a reactive distillation column connected in series.

[0057] Example 1: A single plug flow reactor + reactive distillation column, with no water added to the reactive distillation column, has a water to EO ratio of 22:1 (in moles) in the feed stream of the plug flow reactor.

[0058] Example 1 simulates the reaction composition of a water-to-ethylene oxide molar ratio of 22:1 in a plug flow reactor. After optimal conversion, the reaction mixture was fed into a reactive distillation column, where complete reaction was achieved. The simulated reaction conditions and results of Example 1 are shown in Table 1.

[0059] Table 1

[0060]

[0061]

[0062] Example 2: Single plug flow reactor + reactive distillation column, with water added to the reactive distillation column; the overall water to ethylene oxide ratio is 22:1 (in moles).

[0063] In Example 2, the simulation involved feeding a reactant composition containing a water to ethylene oxide molar ratio of 12:1 into a reactor, and after optimal conversion, feeding the reaction mixture into a reactive distillation column, with water fed from the top tray (so that the total water used in the process corresponds to a water to ethylene oxide molar ratio of 22:1). The simulated reaction conditions and results of Example 2 are shown in Table 2. A comparison between Table 2 and Table 1 shows that this system can reduce the required water to ethylene oxide ratio in the initial feed stream of a plug flow reactor and achieve a higher MEG / DEG ratio in the product stream.

[0064] Table 2

[0065]

[0066] As can be observed from Tables 1 and 2, Example 1 provides a better MEG / DEG ratio than Example 2, which achieved a lower conversion rate in a plug flow reactor.

[0067] Example 3: Comparative Example - Single-Plug Flow Reactor

[0068] Example 3 is a simulation in which a reactant composition containing water and ethylene oxide in a ratio of 22:1 was fed into a plug flow reactor, where 100% ethylene oxide conversion was achieved. The simulated reaction conditions and results of Example 3 are shown in Table 3.

[0069] Table 3

[0070]

[0071] The MEG ratio can be increased by the novel processes described in both Example 1 and Example 2.

[0072] Example 4: A single plug flow reactor + reactive distillation column, wherein the ratio of water to ethylene oxide in the feed stream entering the plug flow reactor is 12:1 (in moles).

[0073] Example 4 simulates the reaction composition of a water-to-ethylene oxide molar ratio of 12:1 in a plug flow reactor. After optimal conversion, the reaction mixture was fed into a reactive distillation column, where complete reaction was achieved. The simulated reaction conditions and results of Example 4 are shown in Table 4. A comparison between Table 4 and Table 3 shows...

[0074] Table 4

[0075]

[0076] In Example 5, the simulation involved feeding a reactant composition containing water and ethylene oxide in a 12:1 ratio into a plug flow reactor, where 100% conversion was achieved. The simulated reaction conditions and results of Example 5 are shown in Table 5.

[0077] Table 5

[0078]

[0079] A comparison between Tables 4 and 5 shows that the MEG ratio can be increased through the novel process simulated in Example 4 by incorporating the concepts of a plug flow reactor and a reactive distillation column.

[0080] Example 6: A single plug flow reactor + reactive distillation column, wherein the water to ethylene oxide ratio in the feed stream entering the plug flow reactor is 25:1 (in moles).

[0081] Example 6 simulates the reaction composition of a water-to-ethylene oxide molar ratio of 25:1 in a plug flow reactor. After optimal conversion, the reaction mixture was fed into a reactive distillation column, where complete reaction was achieved. The simulated reaction conditions and results of Example 6 are shown in Table 6.

[0082] Table 6

[0083]

[0084]

[0085] Example 7: Comparative Example - Single-Plug Flow Reactor

[0086] In Example 7, the simulation involved feeding a reactant composition containing a water-to-ethylene oxide ratio of 25:1 into a plug flow reactor, where 100% conversion was achieved. The simulated reaction conditions and results of Example 7 are shown in Table 7. A comparison between Tables 6 and 7 shows that when the molar ratio of water to ethylene oxide in the feed stream is maintained at 25:1, compared to a conventional system with a single plug flow reactor, Figure 1 The system shown can increase the ratio of MEG to DEG in the product stream.

[0087] Table 7

[0088]

[0089] Example 8: A single plug flow reactor + reactive distillation column, wherein the ratio of water to ethylene oxide in the feed stream entering the plug flow reactor is 10:1 (in moles).

[0090] Example 8 simulates the reaction composition of a water-to-ethylene oxide molar ratio of 10:1 in a plug flow reactor. After optimal conversion, the reaction mixture is fed into a reactive distillation column where complete reaction is achieved. The simulated reaction conditions and results of Example 8 are shown in Table 8.

[0091] Table 8

[0092]

[0093]

[0094] Example 9: Comparative Example - Plug Flow Reactor

[0095] In Example 9, the simulation involved feeding a reactant composition containing a water-to-ethylene oxide ratio of 10:1 into a plug flow reactor, where 100% conversion was achieved. The simulated reaction conditions and results of Example 9 are shown in Table 9. A comparison between Tables 8 and 9 shows that when the molar ratio of water to ethylene oxide in the feed stream is maintained at 10:1, compared to a conventional system with a single plug flow reactor, Figure 1 The system shown can increase the ratio of MEG to DEG in the product stream.

[0096] Table 9

[0097]

[0098] Case B: Simulated ethylene glycol production system, which includes, for example, ethylene glycol production systems. Figure 2 The first reactor shown in series

[0099] Separation unit and second reactor

[0100] Use such as Figure 2 The simulation of ethylene glycol production in the system shown was run on the Aspen™ Plus platform. A reaction temperature of 145°C was used in the first reactor. The simulated reaction conditions and results are shown in Table 10.

[0101] Example 10: Production of ethylene glycol in a system comprising two plug flow reactors in series and a separation unit at a reaction temperature of 145°C.

[0102] Table 10

[0103]

[0104] Although it has been referenced Figure 3 and Figure 4 The boxes described embodiments of the present invention, but it should be understood that the operation of the present invention is not limited to these. Figure 3 and Figure 4 The specific boxes and / or the specific order of the boxes shown. Therefore, embodiments of the present invention can use different... Figure 3 and Figure 4 Various boxes in a specific order are used to provide the functionality described in this article.

[0105] In the context of this invention, at least 37 embodiments are now described. Embodiment 1 is a method for producing alkylene glycols. The method includes the steps of: allowing a feed stream containing alkylene oxides and water to flow into a first reactor unit; subjecting the alkylene oxides and water to first reaction conditions in the first reactor unit such that the effluent from the first reactor unit contains alkylene glycols, unreacted alkylene oxides, and unreacted water; allowing at least a portion of the unreacted alkylene oxides and unreacted water to flow into a second reactor unit; and subjecting the unreacted alkylene oxides and unreacted water to second reaction conditions in the second reactor unit sufficient to produce additional alkylene glycols; wherein the second reactor unit is a reactive distillation column, and a higher monoalkylene glycol to dialkylene glycol ratio is produced even at a lower water to alkylene oxide ratio. Embodiment 2 is the method according to Embodiment 1, wherein the alkylene glycol is ethylene glycol, and the alkylene oxide is ethylene oxide. Embodiment 3 is the method according to any one of Embodiments 1 and 2, wherein the first reactor unit includes a plug flow reactor adapted to provide the first reaction conditions therein. Embodiment 4 is the method according to Embodiment 3, further comprising the step of flowing an aqueous stream into the reactive distillation column. Embodiment 5 is the method according to Embodiment 4, wherein the water enters the reactive distillation column at a temperature in the range of 125°C to 150°C. Embodiment 6 is the method according to any one of Embodiments 3 to 5, wherein the reactive distillation column is further adapted to react and distill liquids, and the method further comprises reacting and distilling the effluent of the first reactor unit in the reactive distillation column to produce (1) an overhead stream containing unreacted water and unreacted ethylene oxide and (2) a bottom stream containing unreacted water and monoethylene glycol; and recycling at least a portion of the overhead stream back to the reactive distillation column as reflux. Embodiment 7 is the method according to Embodiment 6, wherein the bottom stream further contains diethylene glycol and / or triethylene glycol. Embodiment 8 is a method according to any one of Embodiments 1 to 2, further comprising the steps of: reacting and separating the effluent of the first reactor unit in a reactive distillation column into a first stream generally containing mainly unreacted water and unreacted ethylene oxide, and a second stream generally containing mainly unreacted water, monoethylene glycol, and unreacted ethylene oxide; allowing the second stream to flow into the second reactor unit; and subjecting the second stream to the second reaction conditions in the second reactor unit. Embodiment 9 is a method according to Embodiment 8, wherein the second stream further comprises diethylene glycol and / or triethylene glycol. Embodiment 10 is a method according to any one of Embodiments 8 and 9, wherein the second reaction conditions in the second reactor unit are non-catalytic reaction conditions.Embodiment 11 is the method according to any one of Embodiments 8 to 10, wherein the second reaction conditions in the second reactor unit include a reactor inlet temperature in the range of 160°C to 220°C and a reaction pressure of 10 bar to 20 bar. Embodiment 12 is the method according to any one of Embodiments 8 to 11, further comprising recovering at least a portion of ethylene oxide from the first stream for use in the production of pure ethylene oxide. Embodiment 13 is the method according to any one of Embodiments 1 to 12, wherein the first reactor has a reaction residence time of 0.5 minutes to 8 minutes. Embodiment 14 is the method according to claim 13, further comprising recovering at least a portion of ethylene oxide from the first stream for use in the production of pure ethylene oxide. Embodiment 15 is the method according to any one of Embodiments 2 to 14, wherein the effluent of the first reactor unit further comprises diethylene glycol and / or triethylene glycol. Embodiment 16 is the method according to any one of Embodiments 2 to 15, wherein the first reaction conditions and the second reaction conditions are non-catalytic reaction conditions. Implementation scheme 17 is the method according to any one of implementation schemes 2 to 16, wherein the reaction conditions in the first reactor unit include a reactor inlet temperature in the range of 120°C to 160°C, a reaction pressure of 18 bar to 25 bar, and a residence time of 0.5 minutes to 8.0 minutes.

[0106] Embodiment 18 is a method for producing ethylene glycol. The method includes the following steps: feeding ethylene oxide and water into a first reactor, subjecting the ethylene oxide and water in the first reactor to reaction conditions sufficient to produce ethylene glycol, such that a first effluent from the first reactor contains monoethylene glycol, unreacted ethylene oxide, and unreacted water; separating the first effluent in a separation unit into a first stream generally containing mainly unreacted water and unreacted ethylene oxide and a second stream generally containing mainly unreacted ethylene oxide, unreacted water, and monoethylene glycol; feeding the second stream into a second reactor; and subjecting the second stream in the second reactor to reaction conditions sufficient to produce additional monoethylene glycol; wherein the second reactor unit is a reactive distillation unit. Embodiment 19 is the method according to Embodiment 18, further comprising the step of recycling at least a portion of the first stream back to the first reactor to produce additional ethylene glycol. Embodiment 20 is the method according to any one of Embodiments 8 or 18, wherein the separation of the first effluent to produce the first and second effluents is carried out at a top boiling temperature range of 150°C to 180°C and a pressure range of 6 bar to 20 bar. Embodiment 21 is the method according to any one of Embodiments 18 to 20, wherein the effluent from the first reactor further contains diethylene glycol and / or triethylene glycol. Embodiment 22 is the method according to any one of Embodiments 18 to 21, wherein the second effluent further contains diethylene glycol and / or triethylene glycol. Embodiment 23 is the method according to any one of Embodiments 18 to 22, wherein the reaction conditions in the first reactor are non-catalytic reaction conditions. Embodiment 24 is the method according to any one of Embodiments 18 to 23, wherein the reaction conditions in the second reactor are non-catalytic reaction conditions. Embodiment 25 is the method according to any one of Embodiments 18 to 24, wherein all the ethylene oxide flowing into the second reactor is converted in the second reactor. Embodiment 26 is the method according to any one of embodiments 18 to 25, wherein the reaction conditions in the first reactor include a reaction temperature in the range of 130°C to 150°C. Embodiment 27 is the method according to any one of embodiments 18 to 26, wherein the reaction conditions in the first reactor include a reaction pressure of 18 bar to 22 bar. Embodiment 28 is the method according to any one of embodiments 18 to 27, wherein the reaction conditions in the first reactor include a residence time of 0.5 minutes to 1.0 minute. Embodiment 29 is the method according to any one of embodiments 18 to 28, wherein the reaction conditions in the second reactor include a reaction temperature in the range of 160°C to 180°C. Embodiment 30 is the method according to any one of embodiments 18 to 29, wherein the reaction conditions in the second reactor include a reaction pressure of 10 bar to 20 bar.Embodiment 31 is the method according to any one of embodiments 18 to 30, wherein the reaction conditions in the first reactor include a residence time of 5 to 8 minutes. Embodiment 32 is the method according to any one of embodiments 18 to 31, wherein the effluent from the first reactor is separated in the distillation column. Embodiment 33 is the method according to any one of embodiments 18 to 32, wherein the method is capable of producing monoethylene glycol and diethylene glycol in a molar ratio of 15 to 18.5. Embodiment 34 is the method according to any one of embodiments 18 and 19, wherein the method further includes recovering at least a portion of the first stream to an ethylene oxide purification unit to produce ethylene oxide.

[0107] Embodiment 35 is a method for producing alkylene glycols. The method includes feeding alkylene oxide and water into a first reactor unit. The method further includes subjecting the alkylene oxide and water to first reaction conditions in the first reactor unit, such that the effluent from the first reactor unit contains alkylene glycols, unreacted alkylene oxides, and unreacted water. The method further includes feeding at least a portion of the unreacted alkylene oxides into a reactive distillation unit. The method further includes subjecting the unreacted alkylene oxides to second reaction conditions in the reactive distillation unit sufficient to produce additional alkylene glycols. Embodiment 36 is a method for producing ethylene glycol. The method includes feeding ethylene oxide and water into a first reactor. The method further includes subjecting the ethylene oxide and water to reaction conditions sufficient to produce ethylene glycol in the first reactor, such that the first effluent from the first reactor contains monoethylene glycol, unreacted ethylene oxide, and unreacted water. The method further includes separating the first effluent in a separation unit into a first stream generally consisting primarily of unreacted water and unreacted ethylene oxide, and a second stream generally consisting primarily of unreacted ethylene oxide, unreacted water, and monoethylene glycol. The method further includes flowing the second stream into a reactive distillation unit. The method further includes subjecting the second stream in the reactive distillation unit to reaction conditions sufficient to produce additional monoethylene glycol. Embodiment 37 is a method for producing ethylene glycol. The method includes flowing ethylene oxide and water into a first reactor. The method further includes subjecting the ethylene oxide and water in the first reactor to reaction conditions sufficient to produce ethylene glycol, such that the first effluent from the first reactor contains monoethylene glycol, unreacted ethylene oxide, and unreacted water. The method further includes separating the first effluent in a separation unit into a first stream generally consisting primarily of unreacted water and unreacted ethylene oxide, and a second stream generally consisting primarily of unreacted ethylene oxide, unreacted water, and monoethylene glycol. The method further includes flowing the second stream into a second reactor. The method further includes subjecting the second stream in the second reactor to reaction conditions sufficient to produce additional monoethylene glycol.

[0108] Although the embodiments and advantages of this application have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, means, methods, and steps described herein. As will be readily understood by those skilled in the art from the foregoing disclosure, existing or future processes, machines, manufactures, compositions of matter, apparatuses, methods, or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, apparatuses, methods, or steps within their scope.

Claims

1. A method for producing alkylene glycols, the method comprising: The feed stream containing alkyl epoxides and water flows into the first reactor unit; The alkylene oxide and water are subjected to a first reaction condition in the first reactor unit such that the effluent of the first reactor unit contains alkylene glycol, unreacted alkylene oxide, and unreacted water. At least a portion of the unreacted alkylene oxides and unreacted water is diverted to the second reactor unit; as well as The unreacted alkylene oxide and unreacted water are subjected to second reaction conditions in the second reactor unit sufficient to produce additional alkylene glycols; The first reactor unit includes a plug flow reactor adapted to provide the first reaction conditions therein; The second reactor unit is a reactive distillation column, which can produce a high monoalkylene glycol to dialkylene glycol ratio even at a low water to alkylene oxide ratio.

2. The method according to claim 1, wherein the alkylene glycol is ethylene glycol and the alkylene oxide is ethylene oxide.

3. The method according to claim 1, wherein the method further comprises: The water stream is then fed into the reactive distillation column.

4. The method according to claim 3, wherein the water enters the reactive distillation column at a temperature in the range of 125°C to 150°C.

5. The method according to any one of claims 1 to 4, wherein the reactive distillation column is further adapted to react and distill the liquid, and the method further comprises: The effluent from the first reactor unit is reacted and distilled in the reactive distillation column to produce (1) an overhead stream containing unreacted water and unreacted ethylene oxide and (2) a bottom stream containing unreacted water and monoethylene glycol; and at least a portion of the overhead stream is recycled back to the reactive distillation column as reflux.

6. The method of claim 5, wherein the bottom stream further comprises diethylene glycol and / or triethylene glycol.

7. The method according to any one of claims 1 to 2, wherein the method further comprises: The effluent from the first reactor unit is reacted and separated in the reactive distillation column into a first stream that generally contains mainly unreacted water and unreacted ethylene oxide, and a second stream that generally contains mainly unreacted water, monoethylene glycol, and unreacted ethylene oxide. The second stream flows into the second reactor unit; and The second stream is subjected to the second reaction conditions in the second reactor unit.

8. The method of claim 7, wherein the second stream further comprises diethylene glycol and / or triethylene glycol.

9. The method according to claim 7, wherein the second reaction conditions in the second reactor unit are non-catalytic reaction conditions.

10. The method of claim 7, wherein the second reaction conditions in the second reactor unit include a reactor inlet temperature in the range of 160°C to 220°C and a reaction pressure of 10 bar to 20 bar.

11. The method of claim 7, further comprising recovering at least a portion of the ethylene oxide from the first stream for use in the production of pure ethylene oxide.

12. The method according to any one of claims 1 to 4, wherein the first reactor unit has a reaction residence time of 0.5 minutes to 8 minutes.

13. The method of claim 7, further comprising recovering at least a portion of the ethylene oxide from the first stream for use in the production of pure ethylene oxide.

14. The method of claim 2, wherein the effluent of the first reactor unit further comprises diethylene glycol and / or triethylene glycol.

15. The method according to claim 2, wherein the first reaction conditions and the second reaction conditions are non-catalytic reaction conditions.

16. The method according to claim 2, wherein the first reaction conditions in the first reactor unit include: Reactor inlet temperature in the range of 120°C to 160°C, reaction pressure in the range of 18 bar to 25 bar, and residence time in the range of 0.5 minutes to 8.0 minutes.

17. The method of claim 7, wherein separating the effluent from the first reactor unit to produce a first stream and a second stream is carried out in a column top boiling temperature range of 150°C to 180°C and a pressure range of 6 bar to 20 bar.

18. A method for producing ethylene glycol, the method comprising: Ethylene oxide and water are fed into the first reactor: The ethylene oxide and water are subjected to reaction conditions in the first reactor sufficient to produce ethylene glycol, such that the first effluent from the first reactor contains monoethylene glycol, unreacted ethylene oxide, and unreacted water. In the separation unit, the first effluent stream is separated into a first stream that generally mainly contains unreacted water and unreacted ethylene oxide and a second stream that generally mainly contains unreacted ethylene oxide, unreacted water and monoethylene glycol. The second stream flows into the second reactor; and The second stream is subjected to reaction conditions in the second reactor sufficient to produce additional monoethylene glycol; The first reactor is a plug flow reactor; The second reactor is a reactive distillation unit.

19. The method of claim 18, further comprising: At least a portion of the first stream is recycled back to the first reactor to produce additional ethylene glycol.

20. The method of claim 18, wherein separating the first effluent stream to produce the first stream and the second stream is carried out in a column top boiling temperature range of 150°C to 180°C and a pressure range of 6 bar to 20 bar.

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