Hybrid contact tray for a mass transfer column
View Patent ↗A hybrid contact tray for a mass transfer column is provided. The contact tray includes a tray deck for passage of liquid along a liquid flow path thereon. The tray deck has a plurality of orifices for passage of ascending vapor through the tray deck, a cross-current vapor-liquid mixing section having a first portion of the plurality of orifices, and a co-current vapor-liquid mixing section including at least one co-current mixing device associated with a second portion of the plurality of orifices. The tray deck also has features capable of altering liquid head levels with respect to the plurality of orifices such that the liquid head level within the co-current vapor-liquid mixing section is greater than the liquid head level within the cross-current vapor-liquid mixing section.
1. A hybrid contact tray for a mass transfer column, the hybrid contact tray comprising:
a tray deck for passage of liquid along a liquid flow path thereon, the tray deck having a plurality of orifices for passage of ascending vapor through the tray deck;
a cross-current vapor-liquid mixing section having a first portion of the plurality of orifices;
a co-current vapor-liquid mixing section comprising at least one co-current mixing device associated with a second portion of the plurality of orifices; and
means for altering liquid head levels with respect to the plurality of orifices such that the liquid head level within the co-current vapor-liquid mixing section is greater than the liquid head level within the cross-current vapor-liquid mixing section.
2. The hybrid contact tray according to claim 1 , wherein the co-current vapor-liquid mixing device comprises a conduit having: a vapor inlet in fluid communication with one or more of the second portion of orifices; a froth inlet in fluid communication with the liquid flow path along the tray deck; a fluid outlet; and a co-current flow path of vapor and liquid within the conduit disposed after the vapor and froth inlets and before the fluid outlet.
3. The hybrid contact tray according to claim 2 , wherein the conduit has a packing material disposed within the co-current flow path of vapor and liquid.
4. The hybrid contact tray according to claim 3 , wherein the packing material is selected to increase interfacial surface area between the vapor and liquid in the conduit.
5. The hybrid contact tray according to claim 4 , wherein the packing material is selected from the group consisting of: a corrugated metal sheet, woven metal fibers, braided metal fibers, and randomly bundled metal fibers.
6. The hybrid contact tray according to claim 2 , wherein the conduit comprises an inertial separation device disposed within the co-current flow path of vapor and liquid within the conduit, wherein the inertial separation device biases the co-current flow path of vapor and liquid toward an interior wall.
7. The hybrid contact tray according to claim 6 , wherein the froth inlet comprises a tube or trough disposed within the conduit that is in fluid communication with both the liquid flow path along the tray deck and vapor inlet to provide a flow path of liquid within the conduit to the vapor inlet.
8. The hybrid contact tray according to claim 1 , wherein the cross-current vapor-liquid section comprises cross-current mixing devices associated with the first portion of the plurality of orifices.
9. The hybrid contact tray according to claim 8 , wherein the cross-current mixing devices are orifice caps which are positioned within the liquid flow path at a fixed height with respect to the tray deck or change height with respect to the tray deck.
10. The hybrid contact tray according to claim 1 , wherein the means for altering liquid head levels comprises a step-down region in the tray deck along the liquid flow path, wherein the step-down region comprises the co-current mixing section.
11. The hybrid contact tray according to claim 1 , wherein the means for altering liquid head levels comprises a step-up region in the tray deck along the liquid flow path, wherein the step-up region comprises the cross-current mixing section of the tray deck.
12. The hybrid contact tray according to claim 1 , wherein the means for altering liquid head levels comprises a cross-current mixing device comprising orifice extension tubes disposed within or surrounding the each of the first plurality of orifices, wherein during operation the orifice extension extend the orifice to a position intermediate the tray deck and the liquid surface level on the tray.
13. The hybrid contact tray according to claim 1 , wherein the means for altering liquid head levels comprises a combination of weirs disposed in the liquid flow path along the tray deck, the combination of weirs comprising an intermediate weir disposed between the co-current and cross-current mixing sections, and an outlet weir disposed between the final mixing section and an outlet downcomer section.
14. The hybrid contact tray according to claim 13 , wherein the intermediate weir is solid wherein liquid traveling along the liquid flow path flows over the intermediate weir, and wherein the outlet weir comprises apertures and/or slots wherein liquid traveling along the liquid flow path flows through the apertures and/or the slots.
15. The hybrid contact tray according to claim 1 , wherein the liquid flow path along the tray deck is from an inlet downcomer section to an outlet downcomer section, wherein the cross-current and the co-current vapor-liquid mixing sections are disposed along the liquid flow path between the inlet downcomer section and the outlet downcomer section.
16. The hybrid contact tray according to claim 1 , wherein the cross-current vapor-liquid mixing section and the co-current vapor-liquid mixing section are positioned relative to the liquid flow path along the tray deck such that the cross-current vapor-liquid mixing section is disposed upstream from the co-current vapor-liquid mixing section.
17. A mass transfer column with a hybrid contact tray comprising:
a tray deck for passage of liquid along a liquid flow path thereon, the tray deck having a plurality of orifices for passage of ascending vapor through the tray deck;
a cross-current vapor-liquid mixing section having a first portion of the plurality of orifices;
a co-current vapor-liquid mixing section comprising at least one co-current mixing device associated with a second portion of the plurality of orifices; and
means for altering liquid head levels with respect to the plurality of orifices such that the liquid head level within the co-current vapor-liquid mixing section is greater than the liquid head level within the cross-current vapor-liquid mixing section.
18. A method of producing an overhead stream and a bottom stream from one or more feed streams, the method comprising the steps of:
(i) introducing one or more feed streams to a mass transfer column a hybrid contact tray comprising:
a tray deck for passage of liquid along a liquid flow path thereon, the tray deck having a plurality of orifices for passage of ascending vapor through the tray deck;
a cross-current vapor-liquid mixing section having a first portion of the plurality of orifices;
a co-current vapor-liquid mixing section comprising at least one co-current mixing device associated with a second portion of the plurality of orifices; and
means for altering liquid head levels with respect to the plurality of orifices such that the liquid head level within the co-current vapor-liquid mixing section is greater than the liquid head level within the cross-current vapor-liquid mixing section,
(ii) treating the mass transfer column under operating conditions sufficient to create a tops stream and a bottoms stream,
thereby producing an overhead stream and a bottoms stream from one or more feed streams.
19. The method of claim 18 , wherein the operating conditions in step (ii) include an operating pressure above atmospheric pressure.