Screw conveyor adsorption moving bed with heat integration
Systems and methods presented herein provide for a screw conveyor adsorption moving bed that separates carbon dioxide from a gas mixture. Adsorbent particles are transported between an adsorption section of the reactor, which can be an outer column, and a desorption section, which can be an inner column. The particle transport is facilitated by the screw conveyor located inside the inner column. The screw conveyor is specially designed to have a hollow screw, shaped as a spiral surface, attached to a central shaft. The screw surface is also equipped with plurality of holes and a flexible edge attachment to seal against the cylindrical surface. The hollow shape allows the gas to flow from the inlet of the shaft to the particles through the holes on the screw, thus creating uniform gas distribution.
1 . A method for removing carbon dioxide from gas, comprising:
exposing, within an outer container, adsorbent particles to a gas mixture that contains carbon dioxide (CO 2 );
using a screw conveyor in a cylinder that is inside the outer container, moving the adsorbent particles around a shaft towards a top opening of the cylinder;
passing a heated gas through a hollow part of the shaft of the cylinder to heat the adsorbent particles;
desorbing the CO 2 from the adsorbent particles; and
ejecting the desorbed CO 2 from the hollow part of the shaft.
2 . The method of claim 1 , wherein the screw conveyor includes a flexible rubber edge at a screw intake, wherein a screw of the screw conveyor is flexible and rubber at a portion that contacts the screw intake.
3 . The method of claim 1 , comprising:
filling a bottom portion of the outer container with a sealing liquid, wherein the screw conveyor raises the adsorbent particles into the cylinder from the sealing liquid; and
cycling the sealing liquid through a sieve mesh positioned at an end of the screw conveyor in the bottom portion below a bottom opening of the cylinder.
4 . The method of claim 1 , wherein the screw conveyor comprises a hollow spiral attached to the hollow shaft, wherein the hollow spiral comprises a plurality of holes in fluid connection to the hollow part of the shaft.
5 . The method of claim 1 , wherein the cylinder includes a top opening, wherein the screw conveyor pushes the adsorbent particles out of the top opening into the outer container.
6 . The method of claim 1 , comprising outputting a CO 2 -lean gas separated from the gas mixture to a heat exchanger, which returns the CO 2 -lean gas as the heated gas through the hollow shaft.
7 . The method of claim 1 , wherein the adsorbent particles include a Metal-Organic Framework (MOF).
8 . The method of claim 7 , wherein the adsorbent particles include a MOF having one or more bonded MOF crystals.
9 . The method of claim 8 , wherein the adsorbent particles include a monolithic MOF.
10 . The method of claim 1 , wherein the adsorbent particles include a porous carbon, alkalized alumina, zeolite, or amine-functionalized sorbent.
11 . A screw conveyor adsorption moving bed, comprising:
an outer adsorption chamber;
an inner desorption chamber within the outer adsorption chamber;
a screw conveyor at least partially inside the inner desorption chamber, the screw conveyor including a spiral screw and a central shaft; and
a gas input configured to receive a gas mixture that contains carbon dioxide (CO 2 ),
wherein adsorbent particles in the outer adsorption chamber are configured to adsorb the CO 2 from the gas mixture,
wherein the adsorbent particles are cycled on the screw conveyor, and
wherein a hot gas is passed through the central shaft, causing desorption of the CO 2 from the adsorbent particles, and
wherein the desorbed CO 2 is configured to exit the inner desorption chamber through the central shaft.
12 . The screw conveyor adsorption moving bed of claim 11 , wherein the spiral screw includes a plurality of holes.
13 . The screw conveyor adsorption moving bed of claim 11 , further comprising a gas outlet for CO 2 -lean gas separated from the gas mixture, wherein the gas outlet is coupled to a heat exchanger that captures unused thermal energy from the inner desorption chamber for at least partial reuse in desorption.
14 . The screw conveyor adsorption moving bed of claim 11 , wherein the adsorption chamber is maintained at lower temperature than the desorption chamber.
15 . The screw conveyor adsorption moving bed of claim 11 , further comprising a bottom portion with a sealing liquid and a sieve mesh positioned below the screw conveyor, wherein the sealing liquid includes the adsorbent particles, and the sealing liquid is recirculated through the sieve mesh that substantially prevents recirculation of the adsorbent particles.
16 . The screw conveyor adsorption moving bed of claim 15 , comprising a pump and a powder filter coupled to the bottom portion, wherein the pump is configured to circulate the sealing liquid.
17 . The screw conveyor adsorption moving bed of claim 11 , wherein the adsorption chamber is configured to move the gas mixture up and to move the adsorbent particles down, wherein the desorption chamber is configured to move the adsorbent particles up and the desorbed CO 2 down.
18 . The screw conveyor adsorption moving bed of claim 11 , wherein the adsorbent particles include a Metal-Organic Framework (MOF).
19 . The screw conveyor adsorption moving bed of claim 18 , wherein the adsorbent particles include a MOF having one or more bonded MOF crystals.
20 . The screw conveyor adsorption moving bed of claim 11 , wherein the adsorbent particles include a porous carbon, alkalized alumina, zeolite, or amine-functionalized sorbent.