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JP-2026075430-A - Crystalline silicoaluminophosphate, method for producing crystalline silicoaluminophosphate, molded body, adsorbent, and method for producing purified gas

JP2026075430AJP 2026075430 AJP2026075430 AJP 2026075430AJP-2026075430-A

Abstract

[Problem] To provide a crystalline silicoaluminophosphate, a method for producing crystalline silicoaluminophosphate, a molded article, an adsorbent, and a method for producing purified gas, all of which have excellent carbon dioxide adsorption performance. [Solution] A crystalline silicoaluminophosphate containing at least one cation species selected from the group consisting of alkali metals and alkaline earth metals, a method for producing the crystalline silicoaluminophosphate, a molded body, an adsorbent, and a method for producing purified gas. [Selection Diagram] Figure 1

Inventors

  • 大久保 敦史

Assignees

  • 旭化成株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (17)

  1. A crystalline silicoaluminophosphate containing at least one cation species selected from the group consisting of alkali metals and alkaline earth metals.
  2. The crystalline silicoaluminophosphate according to claim 1, comprising potassium as the cation species.
  3. The crystalline silicoaluminophosphate according to claim 2, wherein the ratio of potassium atom concentration to aluminum atom concentration (K/Al) is 0.05 or higher.
  4. The crystalline silicoaluminophosphate according to claim 1, wherein the ratio (A/T) of the total molar amounts of potassium and lithium to the total molar amount (T) of alkali metals in the crystalline silicoaluminophosphate is 0.05 or greater.
  5. A crystalline silicoaluminophosphate according to claim 1, which is of the GIS type.
  6. The crystalline silicoaluminophosphate according to claim 1, wherein the diffraction peaks obtained by X-ray diffraction are in the ranges of 2θ = 12.02° to 12.75° and 2θ = 27.42° to 28.22°.
  7. A step in preparing a mixed gel containing a silicon source, an aluminum source, a phosphorus source, and water, A hydrothermal synthesis step is performed by hydrothermally synthesizing the mixed gel under conditions of a temperature of 80°C to 300°C to obtain crystalline silicoaluminophosphate, A cation exchange step involves cation exchange of the cation species of the crystalline silicoaluminophosphate with at least one cation species selected from the group consisting of alkali metals and alkaline earth metals. A method for producing crystalline silicoaluminophosphates, including [the specified compound].
  8. A calcination step in which the crystalline silicoaluminophosphate obtained by the hydrothermal synthesis step is calcined, A method for producing crystalline silicoaluminophosphate according to claim 7, further comprising:
  9. The method for producing crystalline silicoaluminophosphate according to claim 8, wherein the pressure during firing in the aforementioned firing step is 50 kPaA or less.
  10. The method for producing crystalline silicoaluminophosphate according to claim 8, wherein the firing temperature in the firing step is 80°C to 300°C.
  11. A method for producing crystalline silicoaluminophosphate according to claim 8, further comprising a post-calcination step of calcining the crystalline silicoaluminophosphate obtained by the cation exchange step at a pressure of 50 kPa or less.
  12. A method for producing crystalline silicoaluminophosphate according to claim 11, further comprising a post-cation exchange step in which the cation species of crystalline silicoaluminophosphate are exchanged for at least one cation species selected from the group consisting of alkali metals and alkaline earth metals after the post-calcination step.
  13. A molded article comprising a crystalline silicoaluminophosphate according to any one of claims 1 to 6.
  14. An adsorbent comprising the crystalline silicoaluminophosphate described in any one of claims 1 to 6.
  15. A method for separating carbon dioxide from a mixed gas containing carbon dioxide using an adsorbent, A separation method comprising an adsorption step of bringing a mixed gas containing carbon dioxide into contact with the adsorbent described in claim 14, thereby adsorbing carbon dioxide onto the adsorbent.
  16. The separation method according to claim 15, comprising a desorption step of removing carbon dioxide from an adsorbent by placing the adsorbent, which has adsorbed carbon dioxide, under reduced pressure.
  17. A method for producing purified carbon dioxide, comprising the separation method described in claim 15.

Description

This invention relates to crystalline silicoaluminophosphate, a method for producing crystalline silicoaluminophosphate, a molded article, an adsorbent, and a method for producing purified gas. Zeolites are used as adsorbents for various chemical substances, and are particularly useful for gas separation. To utilize this property, zeolites are used for the separation and recovery of carbon dioxide. Patent Document 1 discloses a GIS-type zeolite that has little distortion or defects in the crystal lattice, a clearly formed crystal structure, and can sufficiently adsorb carbon dioxide ( CO₂ ) while exhibiting high selectivity for carbon dioxide adsorption relative to the amount of methane ( CH₄ ) adsorbed. This GIS-type zeolite has an aluminum atom content of 1% by mass or more and a phosphorus atom content of 4% by mass or less, and the carbon dioxide saturation adsorption amount a of the GIS-type zeolite, measured when the GIS-type zeolite and carbon dioxide are placed in a system at 25°C and 760 mmHg, is 5 cm³ /g or more at 25°C and 760 mmHg. Patent Document 2 discloses a GIS-type zeolite that can sufficiently adsorb carbon dioxide ( CO₂ ) and has high selectivity for carbon dioxide adsorption relative to the amount of methane ( CH₄ ) adsorbed. This GIS-type zeolite has a diffraction peak of (10¹) between 2θ = 12.55 and 12.90° in the spectrum obtained by X-ray diffraction. International Publication WO2018/110559International Publication WO2019/202933 Figure 1 is a diagram illustrating an adsorption device according to this embodiment. The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). The present invention is not limited to the following description and can be implemented in various modifications within the scope of its gist. In this specification, for example, a numerical range expressed as "1 to 100" includes both its lower limit "1" and upper limit "100". The same applies to other numerical range expressions. [Crystalline silica aluminophosphate] The crystalline silicoaluminophosphate according to this embodiment contains at least one cation species selected from the group consisting of alkali metals and alkaline earth metals. This configuration makes it possible to provide a crystalline silicoaluminophosphate, a method for producing the crystalline silicoaluminophosphate, a molded body, an adsorbent, and a separation method that have excellent carbon dioxide adsorption performance. Crystalline silicoaluminophosphate refers to zeolite-related materials whose framework consists of silicon (Si), aluminum (Al), phosphorus (P), and oxygen (O). "Crystalline" means that a diffraction peak is obtained by X-ray diffraction, and the intensity of the obtained diffraction peak is 100 times or more the amplitude of the background fluctuation. The crystalline silicoaluminophosphate according to this embodiment is preferably of the GIS type. The GIS type refers to a structure that, when expressed using the IUPAC structure code (hereinafter simply referred to as "structure code") defined by the Structure Commission of the International Zeolite Association (IZA), is of the GIS type. In this embodiment, the crystalline silicoaluminophosphate preferably has diffraction peaks in the ranges of 2θ = 12.02° to 12.75° and 2θ = 27.42° to 28.22° in the peaks obtained by X-ray diffraction. Having these diffraction peaks makes the GIS-type structure contained in the crystalline silicoaluminophosphate more prominent, thereby further improving carbon dioxide absorption. Furthermore, in the peaks obtained by X-ray diffraction of the crystalline silicoaluminophosphate according to this embodiment, when the peak height at 2θ = 11.82° to 12.65° is denoted as A, and the peak height at approximately 2θ = 17.4° is denoted as B, the value of B/A is preferably 0.10 or more, more preferably 0.20 or more, and more preferably 0.30 or more. The upper limit of the value of B/A is not particularly limited, but for example, it is 0.8 or less. "Approximately" in the context of the peak refers to a region of ±0.5°. (cationic species) The crystalline silicoaluminophosphate according to this embodiment contains at least one cationic species selected from the group consisting of alkali metals and alkaline earth metals. By including this cationic species, the amount of carbon dioxide absorbed by the crystalline silicoaluminophosphate can be further improved. Examples of alkali metals include lithium, sodium, and potassium. Examples of alkaline earth metals include magnesium and calcium. Among these, crystalline silicoaluminophosphates preferably contain lithium or potassium, and more preferably potassium. The inclusion of potassium can further improve the carbon dioxide absorption capacity of crystalline silicoaluminophosphates. (A/T) The total potassium and lithium content in the crystalline silicoaluminophosphate according to this embodiment is calculated as the ratio (A