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EP-4739413-A1 - APPARATUS FOR AND METHOD OF HETEROAZEOTROPIC EXTRACTIVE DISTILLATION

EP4739413A1EP 4739413 A1EP4739413 A1EP 4739413A1EP-4739413-A1

Abstract

A heteroazeotropic extractive distillation method is performed using two-stage heteroazeotropic extractive distillation within at least one distillation column (100, 102). A first stage (10) comprising distilling a first mixture (104) of water, at least acetic acid and formic acid and entrainer inside a temperature range difference 5°C to 20°C for separating water from the first mixture (104), which has a first percentage of said entrainer and a first percentage of water. A second stage (12) receives a bottom product of water, at least acetic acid and formic acid and said entrainer from a bottom section (108) of the first stage (10). The second stage (12) has a second percentage of said entrainer and a second percentage of water, wherein the second percentage of said entrainer being greater than the first percentage of said entrainer, and/or the first percentage of water being greater than the second percentage of water. At least a part of overhead vapor of at least one of the first stage (10) and the second stage (12) is pressurized by vapor recompression. At least a part of the first mixture (104) is circulated back to the first stage (10), and heat of the overhead vapor to first mixture (104) is circulated to the first stage (10).

Inventors

  • KANTOMAA, JUHANI
  • ANTTILA, JUHA RAINER

Assignees

  • Chempolis Oy

Dates

Publication Date
20260513
Application Date
20240702

Claims (15)

  1. 1. A heteroazeotropic extractive distillation method, c h a r a c t e r i z e d by performing a two stage heteroazeotropic extractive distillation within at least one distillation column (100, 102), a first stage (10) of the heteroazeotropic extractive distillation comprising distilling (800) a first mixture (104) of water, at least acetic acid and formic acid and entrainer inside a temperature range difference 5°C to 20°C within the first stage for separating water from the first mixture (104) through distillation, the entrainer being a former of a minimum boiling azeotrope and an extractant in the first mixture (104), and the first mixture (104) having a first percentage of said entrainer and a first percentage of water; a second stage (12) of the heteroazeotropic extractive distillation, the second stage (12) being separate from the first stage (10), receiving (802) a bottom product of water, at least acetic acid and formic acid and said entrainer from a bottom section (108) of the first stage (10), the second stage (12) including a second mixture (106) having a second percentage of said entrainer and a second percentage of water, wherein the second percentage of said entrainer of the second stage (12) being greater than the first percentage of said entrainer of the first stage (10), and/or the first percentage of water of the first stage (10) being greater than the second percentage of water of the second stage (12), the second percentages of water and said entrainer being at least partially based on the bottom product received from the first stage (10); pressurizing (804) at least a part of overhead vapor of at least one of the first stage (10) and the second stage (12) by vapor recompression; and circulating (806) at least a part of the first mixture (104) of the first stage (10) back to the first stage (10), and transferring heat of the overhead vapor to first mixture (104) circulated to the first stage (10).
  2. 2. The method of claim 1, c h a r a c t e r i z e d by performing the first stage of said heteroazeotropic extractive distillation within a first distillation column (100), a second distillation column (102) of heteroazeotropic extractive distillation receiving the bottom product from a bottom section (108) of the first distillation column (100), and performing the second stage of said heteroazeotropic extractive distillation within the second distillation column (102), the product from the bottom of the first distillation column (100) including water, at least acetic acid and formic acid and said entrainer, where the second percentages of water and said entrainer being at least partially based on the product received from the bottom section (108) of the first column (100); and pressurizing (804) at least a part of the overhead vapor of at least one of the first column (100) and the second column (102), and transferring heat of the overhead vapor that is pressurized to the first mixture (104) of the first column (100).
  3. 3. The method of claim 1, characterized by the entrainer including furfural.
  4. 4. The method of claim 1, characterized by pressurizing (804) including heating the first mixture (104) of the first column (100) such that at least one compressor (112(1), 112(3), 112(5), 112(7), 112(9)) receives the at least a part of the overhead vapor from the first column (100) and/or the second column (102) and increases pressure of said overhead vapor for causing an increase of temperature of said overhead vapor, and transferring heat through heat exchange from said overhead vapor to the first mixture (104) within the first column (100).
  5. 5. The method of claim 4, characterized by performing pressurizing by at least two heat pumps in series.
  6. 6. The method of claim 1, characterized by feeding a third mixture (110) of water, at least acetic acid and formic acid and the entrainer to the second stage (12), a third percentage of said entrainer of the third mixture (110) being greater than the first percentage of said entrainer of the first stage (10), and/or a third percentage of water of third mixture (110) is smaller than the first percentage of water of the first stage (10).
  7. 7. The method of claim 1, c h a r a c t e r i z e d by causing a coefficient of performance (COP) to be 10 or greater based on said pressurizing by vapor recompression of said overhead vapors, and/or enabling a temperature difference that is inside a range 5°C to 20°C within the first stage (10) based on said pressurizing with the vapor recompression of said overhead vapors.
  8. 8. The method of claim 1, c h a r a c t e r i z e d by feeding said overhead vapors of the first stage (10) in a condensed form to a decanter (200), the overhead vapors including water and entrainer caused by the process of the first stage (10), and separating water-rich liquid and entrainer-rich liquid from each other to different streams by the decanter (200).
  9. 9. An apparatus for heteroazeotropic extractive distillation, c h a r a c t e r i z e d in that the apparatus is configured to perform a two stage heteroazeotropic extractive distillation, the apparatus comprising at least one column means (100, 102) of heteroazeotropic extractive distillation that is configured to process a first mixture (104) of water, at least acetic acid and formic acid and entrainer in a first stage (10) of the heteroazeotropic extractive distillation for separating water from the first mixture (104) through distillation, the entrainer being a former of azeotrope and an extractant in the first mixture (104), and the first mixture (104) having a first percentage of said entrainer and a first percentage of water; a second stage (12) of the heteroazeotropic extractive distillation that is separate from the first stage (10) and is configured to receive a bottom product including water, at least acetic acid and formic acid and said entrainer from a bottom section (108) of the first stage (10), and process a second mixture (106) that has a second percentage of said entrainer and a second percentage of water, wherein the second percentage of water of the second stage (12) is smaller than the first percentage of water of the first stage (10), the second percentages of water and said entrainer being at least partially based on the bottom product received from the bottom section (108) of the first stage (10); a vapor recompression means (112A, 112B, 112C) that is configured to pressurize overhead vapor of the first stage (10); and the apparatus is configured to circulate at least a part of the first mixture (104) of the first stage (10) back to the first stage (10), and transfer heat of the overhead vapor to first mixture (104) circulated back to the first stage (10).
  10. 10. The apparatus of claim 9, characterized in that the entrainer includes furfural.
  11. 11. The apparatus of claim 9, characterized in that at least one heat pump of the vapor recompression means (112A, 112B, 112C) is configured to receive at least a part of said overhead vapors from the first stage (10) and/or the second stage (12) and increase pressure of said overhead vapors for causing an increase of temperature of said overhead vapors, and at least one heat exchanger (112(2), 112(4), 112(6), 112(8), 112(10), 112(12)) configured to transfer heat from said overhead vapors to the first mixture (104) of the first stage (10).
  12. 12. The apparatus of claim 11, characterized in that the vapor recompression means (112A, 112B, 112C) comprises at least two heat pumps in series.
  13. 13. The apparatus of claim 9, characterized that the second stage (12) is configured to receive a third mixture (110) of water, at least acetic acid and formic acid and the entrainer, a third percentage of said entrainer of the third mixture (110) being greater than the first percentage of said entrainer of the first stage (10), and/or a third percentage of water of third mixture (110) is smaller than the first percentage of water of the first stage (10).
  14. 14. The apparatus of claim 9, characterized in that the vapor compression means (112A, 112B, 112C) is configured to cause a coefficient of performance (COP) of the apparatus to be 10 or greater, and/or the vapor compression means (112A, 112B, 112C) is configured to enable a temperature difference that is inside a range 5°C to 20°C within the first stage (10).
  15. 15. The apparatus of claim 9, characterized that the apparatus is configured to feed said overhead vapors of the first stage (10) in a condensed form to a decanter (200), the overhead vapors including water and entrainer caused by the process of the first stage (100), and the decanter (200) is configured to separate water-rich liquid and entrainer-rich liquids from each other to different streams.

Description

Apparatus for and method of heteroazeotropic extractive distillation Field The invention relates to an apparatus for and a method of heteroazeotropic extractive distillation. Background A heteroazeotropic extractive distillation process that can be used as a part of biorefinery is used to separate and recover water, at least one organic acid, and entrainer, which is often furfural. Furfural may have a double role both as an azeotrope forming component and an extractant. The distillation process uses a column for separating the organic acids and water to different streams. The separation requires a lot of energy because water is a lighter component than common acids and it needs to be evaporated. The energy consumption can be lowered by the entrainer that increases the relative volatility between water and acids. Easier separation results in lower ratio. Still, the energy consumption is high and there is a need to improve the process. Brief description The present invention seeks to provide an improvement in the process. The invention is defined by the independent claims. Embodiments are defined in the dependent claims. If one or more of the embodiments is considered not to fall under the scope of the independent claims, such an embodiment is or such embodiments are still useful for understanding features of the invention. List of drawings Example embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which Figures 1 to 6 illustrate various examples of an apparatus for a heteroazeotropic extractive distillation process with one or more vapor recompression devices increases pressure of at least a part of overhead vapor of at least one of a first and or second column and transfers heat of the vapor to the first mixture of the first column; Figure 7 illustrates an example of the apparatus with a data processing unit; Figure 8 illustrates an example of the data processing unit; and Figure 9 illustrates of an example of a flow chart of a heteroazeotropic extractive distillation method. Description of embodiments The following embodiments are only examples. Although the specification may refer to "an" embodiment in several locations, this does not necessarily mean that each such reference is to the same embodiment's), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. Furthermore, words "comprising" and "including" should be understood as not limiting the described embodiments to consist of only those features that have been mentioned and such embodiments may also contain features/structures that have not been specifically mentioned. All combinations of the embodiments are considered possible if their combination does not lead to structural or logical contradiction. It should be noted that while Figures illustrate various embodiments, they are simplified diagrams that only show some structures and/or functional entities. It is apparent to a person skilled in the art that the described apparatus may also comprise other functions and structures than those described in Figures and text. It should be appreciated that details of some functions, structures, and the signalling used for a measurement and/or control are irrelevant to the actual invention. Therefore, they need not be discussed in more detail here. The expression "azeotrope" refers to a mixture of substances wherein vapour and liquid compositions are identical in a phase equilibrium. The azeotrope corresponds to an extreme point (minimum, maximum or saddle point) in a boiling temperature isobar or in a vapour pressure isotherm. The expression "extractive distillation" refers to distillation wherein entrainer boiling at a relatively high temperature is added to a distillation column above the actual feed flow. Entrainer increases the relative volatility of the components and enhances separation of components, which is the main target of distillation. Extraction, per se, refers to a process wherein a desired substance in a mixture dissolves in a solvent while the rest of the substances are insoluble in said solvent. In the mixture, the substances are completely mixed up with one another and the mixture, perse, may contain end products of chemical reactions. The expression "heteroazeotrope" refers to an azeotrope having, in addition to the vapour phase, two liquid phases present. The expression "heteroazeotropic distillation" refers to either distillation of heteroazeotropic mixtures or distillation wherein a heteroazeotrope forming component ("entrainer") is added to a process. The expression "heteroazeotropic extractive distillation" refers to a combination of heteroazeotropic distillation and extractive distillation. The component to be added, boiling at a relatively high temperature, changes relative volatilies of components to be separated and boiling at a lower temperature, and it