Inertial extraction system
View Patent ↗Disclosed herein are supersonic separation systems that can be used for the removal of CO 2 from a mixed gas stream. Also disclosed are methods for the separation and subsequent collection of solidified CO 2 from a gas stream.
1. A supersonic CO 2 separation system comprising:
a supersonic device comprising:
an entrance for a low pressure gas stream comprising CO 2 ;
a shroud;
a centerbody;
a converging/diverging annular duct between the shroud and the centerbody;
a capture slot configured and positioned to remove particles of solid CO 2 to form a solid CO 2 stream; and
an exit for a supersonic CO 2 -depleted gas stream;
a diffuser configured and positioned to reduce a velocity of the supersonic CO 2 -depleted gas stream to a subsonic speed, and exhibiting a subsonic gas stream exit;
an ejector apparatus comprising:
an ejector inlet connected to the subsonic gas stream exit;
a high pressure fluid inlet duct for inducing a low pressure; and
an ejector apparatus exit;
a swirl generator within the converging/diverging annular duct;
a capture duct comprising an inlet connected to the capture slot, a connection duct tangential to the inlet, and an outlet tangential to the connection duct;
a cyclone particle separator comprising:
a separator inlet connected to the outlet of the capture duct;
a separator exit for a product stream comprising solid CO 2 ; and
a slip gas exit; and
a slip gas recirculation line extending from the slip gas exit and partially through the centerbody of the supersonic device along a centerline of the centerbody, sidewalls of the slip gas recirculation line connected to injection holes within the centerbody exiting into a diverging portion of the converging/diverging annular duct.
2. The system of claim 1 , wherein the swirl generator has a swirl generator entrance and a swirl generator exit, and a converging/diverging annular duct radius at the swirl generator entrance is greater than at the swirl generator exit.
3. The system of claim 1 , further comprising:
the low pressure gas stream at the entrance of the supersonic device, the low pressure gas stream having a pressure within a range from about 5 to about 250 psig and comprising flue gas and from about 2% to about 85% CO 2 by weight; and
the product stream at the separator exit of the cyclone particle separator, an amount of the solid CO 2 in the product stream greater than about 50% by weight based on an amount of CO 2 in the low pressure gas stream.
4. The system of claim 1 , wherein the diffuser comprises:
a converging and diverging section; and
a movable pintle in a fixed outer duct, a diffuser cross-sectional area depending on the position of the movable pintle in the fixed outer duct.
5. The system of claim 1 , further comprising:
a vessel for storing CO 2 downstream of the separator exit of the cyclone particle separator; and
a heat exchanger system comprising:
a first heat exchanger configured and positioned to cool at least one of a portion of the low pressure stream upstream of the supersonic device or a portion of a subsonic gas stream exiting the diffuser with a heat transfer fluid;
a second heat exchanger configured and positioned to vaporize CO 2 in the vessel with the heat transfer fluid to produce self-pressurized supercritical CO 2 ; and
a pump configured and positioned to circulate the heat transfer fluid between the first heat exchanger and the second heat exchanger.
6. The system of claim 1 , wherein the injection holes within the centerbody exhibit a bent configuration between the slip gas recirculation line and the diverging portion of the converging/diverging annular duct.
7. The system of claim 1 , wherein the exit of the supersonic device exhibits a cylindrical shape, and wherein the capture slot comprises an area between the exit and a cylindrical structure circumscribing the exit.
8. The system of claim 1 , wherein an inlet of the swirl generator exhibits a larger diameter than an outlet of the swirl generator.
9. The system of claim 1 , further comprising a water capture slot in the converging/diverging annular duct.
10. A supersonic CO 2 separation system comprising:
a supersonic device comprising:
an entrance for a low pressure gas stream comprising CO 2 ;
a shroud;
a centerbody;
a converging/diverging annular duct between the shroud and the centerbody;
a capture slot for receiving solid CO 2 ; and
an exit for a supersonic CO 2 -depleted gas stream;
a capture duct configured to substantially reduce the axial velocity of a material stream directed thereto while maintaining the tangential momentum of the material stream, the capture duct comprising an inlet connected to the capture slot, a duct connected to the inlet, and an outlet connected to the duct and tangentially aligned with at least one of the capture slot or the duct;
a diffuser configured to reduce the velocity of the supersonic CO 2 -depleted gas stream to a subsonic speed, the diffuser having a subsonic gas stream exit and comprising:
a converging and diverging section; and
a movable pintle in a fixed outer duct, a diffuser cross-sectional area depending on the position of the movable pintle in the fixed outer duct;
a swirl generator positioned in the converging/diverging annular duct and having a swirl generator entrance and a swirl generator exit, a converging/diverging annular duct radius at the swirl generator entrance greater than at the swirl generator exit; and
a slip gas recirculation line connected to a particle separator downstream of the capture duct and extending from the particle separator and partially through the centerbody of the supersonic device along a centerline of the centerbody, sidewalls of the slip gas recirculation line connected to injection holes within the centerbody exiting into a diverging portion of the converging/diverging annular duct.
11. The system of claim 10 , wherein the swirl generator has a swirl generator centerline, and an average angle between the swirl generator centerline and the centerline of the centerbody is in a range from about 5 to 90 degrees.
12. The system of claim 10 , wherein an aerodynamic throat of the converging/diverging duct has a throat centerline, and an angle between the throat centerline and the centerline of the centerbody is in a range from about 5 to 90 degrees.
13. The system of claim 10 , wherein an angle at the exit of the swirl generator δ 2 is characterized by the following equations:
A
_
=
M
2
(
1
+
γ
-
1
2
1
+
γ
-
1
2
M
2
2
)
γ
+
1
2
(
γ
-
1
)
(
1
)
δ
2
=
arctan
[
(
R
throat
/
R
2
)
·
M
2
tan
δ
throat
]
(
2
)
wherein:
A is a ratio of cross-sectional area at an exit of the swirl generator and at a throat of the converging/diverging duct;
δ 2 is a flow swirl angle at the exit of the swirl generator;
δ throat is a flow swirl angle at the throat of the converging/diverging annular duct;
M 2 is a Mach number at an exit from the swirl generator;
R 2 is a radius of the centerline of exit of the swirl generator;
R throat is a radius of the centerline of the throat of the converging/diverging annular duct; and
γ is a ratio of the gas stream specific heats;
wherein the definition of the swirl angle is
δ
=
arctan
(
V
tangential
V
axial
)
.
14. The system of claim 13 , wherein:
R throat /R 2 is in the range of from 0.90 to 1.0; and
Āis in the range of from 1.0 to 2.9.
15. The system of claim 13 , wherein the flow swirl angle downstream of the throat is in a range from about 5 to about 45 degrees.
16. The system of claim 10 , further comprising:
an ejector apparatus comprising:
an ejector inlet connected to the subsonic gas stream exit;
a high pressure fluid inlet duct for inducing a low pressure; and
an ejector apparatus exit.
17. The system of claim 10 , wherein the particle separator comprises a cyclone particle separator.
18. A method for removing CO 2 from a low pressure gas stream, the method comprising:
introducing the low pressure gas stream into a supersonic device and accelerating the gas stream to supersonic speeds, the supersonic device comprising an entrance for the low pressure gas, a shroud, a centerbody, a converging/diverging annular duct between the shroud and the centerbody, a capture slot, and an exit;
swirling the low pressure gas stream while at supersonic speeds using a swirl generator within the converging/diverging annular duct to form a swirling flow stream;
removing particles of solid CO 2 from the swirling flow stream using the capture slot of the supersonic device to form a solid CO 2 stream and a supersonic CO 2 -depleted gas stream;
reducing the velocity of the supersonic CO 2 -depleted gas stream to a subsonic speed using a diffuser to form a subsonic gas stream;
directing the subsonic gas stream through an ejector apparatus comprising an ejector inlet connected to an exit of the diffuser, a high pressure fluid inlet duct for inducing a low pressure, and an ejector apparatus exit;
directing the solid CO 2 stream through a capture duct comprising an inlet connected to the capture slot, a connection duct tangential to the inlet, and an outlet tangential to the connection duct;
delivering the solid CO 2 stream from the capture duct into a cyclone particle separator to form product stream comprising solid CO 2 and a slip gas, the cyclone particle separator comprising a separator inlet connected to the outlet of the capture duct, a separator exit for the product stream, and a slip gas exit; and
recirculating the slip gas into the supersonic device using a slip gas recirculation line extending from the slip gas exit and partially through the centerbody of the supersonic device along a centerline of the centerbody, sidewalls of the slip gas recirculation line connected to injection holes within the centerbody exiting into a diverging portion of the converging/diverging duct.
19. The method of claim 18 , wherein recirculating the slip gas into the supersonic device comprises recirculating the slip gas into the supersonic device prior to removing particles of solid CO 2 from the swirling flow stream using the capture slot of the supersonic device to form the solid CO 2 stream and the supersonic CO 2 -depleted gas stream.
20. The method of claim 18 , further comprising increasing the pressure of the low pressure gas stream prior to introducing the low pressure gas stream into the supersonic device and accelerating the gas stream to supersonic speeds.
21. The method of claim 18 , wherein:
the low pressure gas stream has a pressure less than about 300 psig and comprises from about 2% to about 85% CO 2 by weight; and
the amount of solid CO 2 in the product stream is greater than about 50% by weight based on an amount of CO 2 in the low pressure gas stream.
22. The method of claim 18 , wherein the low pressure gas stream has a pressure within a range from about 5 to about 250 psig and comprises flue gas and from about 3% to about 30% CO 2 by weight.