Extremely large pressure swing adsorption processes for flue gas treatment

Patent metadata

Field	Value
Publication number	US-11717786-B2
Application number	US-202117194759-A
Country	US
Kind code	B2
Filing date	Mar 8, 2021
Priority date	May 8, 2020
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

The current disclosure provides systems and methods for multiple beds undergoing a feed step at the same time with the same feed flow rate and multiple beds undergoing a light reflux step at the same time with the same light reflux flow rate to process a gas stream in a multi-bed, multi-unit vacuum swing adsorption (VSA) process using reasonably sized beds.

First claim

What is claimed is:

1. A system for reducing excessive pressure drop in a pressure swing adsorption process comprising:
a number of beds expressed as n F +n LR −3 wherein at least one bed is a feed bed, n F , and at least one bed is a light reflux bed, n LR ;
a unit block cycle duration t UB expressed as t UB =t 1 +t 2 +t 3 , with the cycle duration t C expressed as t C =t UB (n F +n LR +3),
wherein at least two feed beds undergo a feed step (F) at a same time with a same feed flow rate and at least two light reflux beds undergo a light reflux (LR) step at a same time with a same light reflux flow rate, wherein the feed step and light reflux step durations are substantially equal;
wherein the system undergoes at least one equalization step;
at least one cocurrent heavy reflux (HR) step receiving material from the light reflux step;
at least one cocurrent equalization down (EqD) step;
at least one countercurrent depressurization (CnD) step;
at least one countercurrent LR step receiving a fraction of light product produced during the F step;
at least one countercurrent equalization up (EqU) step that receives all gas leaving the EqD step; and
at least one light product pressurization (LPP) step that receives light product produced during the F step;
at least one idle (I) step followed by at least one partial equalization up (PEqU) step; and
at least one partial equalization down (PEqD) step followed by at least one CnD step.

2. The system of claim 1 , wherein pressure of the beds is returned to approximately 1 atm at the LPP step.

3. The system of claim 1 wherein a system sequence is F1-F2-F3-HR-EqD-PEqD-CnD-LR1-LR2-LR3-LR4-LR5-I-PEqU-I-EqU-LPP.

4. The system of claim 1 , wherein each bed is identical in length L and diameter D as defined by a given aspect ratio R LD to provide D=L/R LD .

5. The system of claim 1 , wherein a 10 ppm limit on O 2 concentration is achieved when CO 2 is a component of a heavy product.

6. The system of claim 1 , wherein adsorbent beads ranging from 3 mm to 9 mm in diameter are employed in beds of the system.

7. A method for reducing excessive pressure drop in a pressure swing adsorption process comprising:
operating in parallel a number of beds expressed as nF+nLR+3 wherein at least one bed is a feed bed, n F , and at least one bed is a light reflux bed, n LR ;
arranging multiple feed beds to undergo a feed step (F) at a same time with a same feed flow rate;
arranging multiple light reflux beds to undergo a light reflux (LR) step at a same time with a same light reflux flow rate;
equalizing substantially duration of the feed step and light reflux step;
undergoing at least one equalization step during the method;
arranging at least one cocurrent heavy reflux (HR) step to receive material from the light reflux step;
providing at least one cocurrent equalization down (EqD) step;
providing at least one countercurrent depressurization (CnD) step;
providing at least one countercurrent LR step receiving a fraction of light product produced during the F step;
providing at least one countercurrent equalization up (EqU) step that receives all gas leaving the EqD step;
providing at least one light product pressurization (LPP) step that receives light product produced during the F step;
providing at least one idle (I) step followed by at least one partial equalization up (PEqU) step; and
providing at least one partial equalization down (PEqD) step followed by at least one CnD step.

8. The method of claim 7 , further comprising returning pressure of the beds to substantially 1 atm at the LPP step.

9. The method of claim 7 further comprising creating a method sequence of F1-F2-F3-HR-EqD-PEqD-CnD-LR1-LR2-LR3-LR4-LR5-I-PEqU-I-EqU-LPP.

10. The method of claim 7 , further comprising forming each bed to be identical in length L and diameter D as defined by a given aspect ratio R LD to provide D=L/R LD .

11. The method of claim 7 , further comprising yielding a 10 ppm limit on O 2 concentration when CO 2 is a component of a heavy product.

Assignees

• Univ South Carolina

Inventors

• Ritter James A
• Ebner Armin D
• Holland Charles E

Classifications

• B01D53/0476 Primary

  Vacuum pressure swing adsorption · CPC title

• B01D53/0407

  Constructional details of adsorbing systems · CPC title

• B01D53/047

  Pressure swing adsorption · CPC title

• B01D2253/108

  Zeolites · CPC title

• B01D2253/304

  Linear dimensions, e.g. particle shape, diameter · CPC title