Search

JP-2026075527-A - GIS-type zeolite, molded body, adsorbent, separation method, method for producing purified carbon dioxide, method for producing purified gas, and separation apparatus

JP2026075527AJP 2026075527 AJP2026075527 AJP 2026075527AJP-2026075527-A

Abstract

[Problem] To provide a GIS-type zeolite with reduced adsorption/desorption hysteresis, a molded body, an adsorbent, a separation method, a method for producing purified carbon dioxide, a method for producing purified gas, and a separation apparatus. [Solution] A GIS-type zeolite having an acid content of 0.01 mmol/g or more per gram of zeolite at 300 to 500°C, as measured by a temperature-induced desorption method; a separation method using the GIS-type zeolite; and a separation apparatus using the GIS-type zeolite. [Selection Diagram] Figure 1

Inventors

  • 大久保 敦史
  • 田中 早弥

Assignees

  • 旭化成株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (16)

  1. GIS-type zeolite with an acid content of 0.01 mmol/g or more per gram of zeolite at 300-500°C, as measured by the temperature-controlled desorption method.
  2. The GIS-type zeolite according to claim 1, wherein the diffraction peak obtained by X-ray diffraction is between 2θ = 12.10° and 13.22°.
  3. The GIS-type zeolite according to claim 1, wherein the diffraction peak obtained by X-ray diffraction is between 2θ = 27.55° and 28.74°.
  4. The GIS-type zeolite according to claim 1, wherein, regarding the ammonia desorption temperature in NH3 - TPD measurement, when the position of the peak with maximum intensity in the temperature range of 300°C or higher is defined as pH (°C), the condition 370°C ≤ pH ≤ 650°C is satisfied.
  5. The GIS-type zeolite according to claim 1, wherein, regarding the ammonia desorption temperature in NH3 - TPD measurement, when the position of the peak with maximum intensity in the temperature range below 300°C is defined as PL (°C), the condition 185°C ≤ PL ≤ 250°C is satisfied.
  6. The GIS-type zeolite according to claim 4, wherein, regarding the ammonia desorption temperature in NH3 - TPD measurement, when PL (°C) is the position of the peak having maximum intensity in the temperature range below 300°C, the condition 185°C ≤ PL ≤ 250°C is satisfied.
  7. A GIS-type zeolite according to claim 1, wherein the silica-alumina ratio is 3.40 or higher.
  8. The GIS-type zeolite according to claim 1, comprising potassium as a cation species in the zeolite.
  9. The GIS-type zeolite according to claim 8, wherein the ratio of the potassium atom concentration to the aluminum atom concentration in the zeolite (K/Al) is 0.05 or higher.
  10. The GIS-type zeolite according to claim 8, wherein the ratio (A/T) of the total amount of potassium and lithium in the zeolite to the total amount of alkali metals (T) is 0.05 or greater.
  11. A molded article comprising a GIS-type zeolite as described in any one of claims 1 to 10.
  12. An adsorbent comprising a GIS-type zeolite as described in any one of claims 1 to 10.
  13. A method for separating carbon dioxide from a mixed gas containing carbon dioxide and a second component gas other than carbon dioxide, using an adsorbent, An adsorption step is performed by bringing the adsorbent into contact with the mixed gas to adsorb carbon dioxide onto the adsorbent, A desorption step is performed by distributing the adsorbent under reduced pressure to remove the carbon dioxide from the adsorbent. Includes, A separation method wherein the adsorbent comprises a GIS-type zeolite as described in any one of claims 1 to 10.
  14. A method for producing purified carbon dioxide, comprising the separation method described in claim 13.
  15. A method for producing purified gas, comprising producing a purified second component gas by the separation method described in claim 13.
  16. A carbon dioxide adsorption tower filled with an adsorbent containing a GIS-type zeolite as described in any one of claims 1 to 10, A mixed gas supply line supplies a mixed gas containing carbon dioxide and a second component gas different from carbon dioxide into the carbon dioxide adsorption tower, A depressurization device for reducing the pressure of the carbon dioxide adsorption tower, A carbon dioxide recovery line that recovers carbon dioxide from carbon dioxide adsorption during depressurization, A separation device having

Description

This invention relates to GIS-type zeolite, molded body, adsorbent, separation method, method for producing purified carbon dioxide, method for producing purified gas, and separation apparatus. Zeolites can be used as adsorbents, desiccants, separation agents, catalysts, catalyst carriers, detergent additives, ion exchange agents, wastewater treatment agents, fertilizers, food additives, cosmetic additives, and more, and are particularly useful for gas separation applications. Among zeolites, those with a GIS structure as defined by the IZA (International Zeolite Association) are called GIS-type zeolites. GIS-type zeolites are zeolites having pores composed of eight-membered oxygen rings. Such GIS-type zeolites are described, for example, in Patent Documents 1 and 2. A GIS-type zeolite is disclosed which has little distortion or defects in the crystal lattice, a clearly formed crystal structure, and can sufficiently adsorb carbon dioxide ( CO₂ ) and has high selectivity for carbon dioxide adsorption relative to the amount of methane ( CH₄ ) adsorbed. The 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 the schematic configuration of the purified gas production apparatus 100 according to this embodiment.Figure 2 is a conceptual diagram showing the carbon dioxide adsorption tower and the changes in the pressure fluctuations of the carbon dioxide adsorption tower over time due to the operation of the purified gas production apparatus 100. 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. [GIS-type zeolite] The GIS-type zeolite according to this embodiment has an acid content of 0.01 mmol/g or more per gram of zeolite at 300 to 500°C, as measured by the temperature-controlled desorption method (TPD). Having the above configuration, it is possible to provide a GIS-type zeolite, a molded article, and a separation method with reduced adsorption-desorption hysteresis. [Amount of acid] In this embodiment, the GIS-type zeolite exhibits reduced adsorption-desorption hysteresis due to the aforementioned acid content being 0.01 mmol/g or more. From a similar viewpoint, the acid content is preferably 0.05 mmol/g or more, more preferably 0.10 mmol/g to 1.00 mmol/g, and even more preferably 0.20 mmol/g to 0.80 mmol/g. The acid content is the amount of acid per gram of zeolite at 300-500°C, and is measured by the temperature-dependent desorption method (TPD). More specifically, the measurement method is as described in the examples. Furthermore, as described later, the acid content can be brought within the above range by acid washing the GIS-type zeolite. [Peak positions P H and P L ] In this embodiment, the GIS-type zeolite preferably satisfies the following conditions for ammonia desorption temperature in NH3 - TPD measurement: when the position of the peak with maximum intensity in the temperature range of 300°C or higher is defined as pH (°C), it preferably satisfies 370°C ≤ pH ≤ 650°C. Having pH (° C ) within this range reduces adsorption and desorption hysteresis. The reason for this is not entirely clear, but it is thought that pH increases as the distance between ion exchange sites in the ultramicropores of the zeolite skeleton increases. With pH above 370°C, the distance between ion exchange sites is appropriately maintained, reducing adsorption and desorption energy. On the other hand, with pH below 650°C, the center of the pores is occupied, suppressing the trapdoor effect. These factors are thought to contribute to the reduction of adsorption and desorption hysteresis. The GIS-type zeolite according to this embodiment more preferably satisfies 380°C ≤ pH ≤ 550°C, and even more preferably satisfies 400°C ≤ pH ≤ 500°C. The pH within the aforementioned range can be controlled by factors such as the strength and concentration of the acid used in the acid washing operation, and