Flow control through plural, parallel connecting channels to/from a manifold
The invention provides apparatuses and techniques for controlling flow between a manifold and two or more connecting microchannels. Flow between plural connecting microchannels, that share a common manifold, can be made more uniform by the use of flow straighteners and distributors that equalize flow in connecting channels. Alternatively, flow can be made more uniform by sections of narrowed diameter within the channels. Methods of making apparatus and methods of conducting unit operations in connecting channels are also described.
1. A chemical processing device comprising:
a manifold comprising an opening;
at least two parallel connecting channels, a first connecting channel and a second connecting channel, connected to and coplanar with the manifold; wherein the manifold is a header manifold, and further comprising a footer manifold; wherein the connecting channels are connected at one end to the header manifold and at the other end to the footer manifold; and
further characterized by a flow control structure that comprises:
a flow straightener connected to the manifold opening; and
a flow distribution section connecting the flow straightener and the parallel connecting channels;
wherein the flow straightener has a length to hydraulic diameter ratio (L fs /D h ) of at least 1 and a cross sectional area; and
wherein the flow distribution section comprises a cross sectional area that is greater than the cross sectional area of the flow straightener.
2. The chemical processing device of claim 1
wherein the flow straightener has a length to hydraulic diameter (L fs /D h ) of at least 5 and a cross sectional area.
3. The chemical processing device of claim 1 possessing a Q factor (Q 1 ) of 10% or less.
4. The chemical device of claim 1 comprising: an exit flow straightener, and exit gate and an exit manifold.
5. The chemical processing device of claim 1 wherein the flow straightener has an exit hydrodynamic dimensionless length of greater than 0.01.
6. The chemical processing device of claim 1 wherein the flow distribution section comprises a flow disruption element selected from the group consisting of: cross-bars, partial barriers, strip fins, pins, and wavy fins.
7. The chemical processing device of claim 1 wherein the header manifold and the footer manifold are arranged in a z-manifold configuration.
8. A chemical processing device comprising:
a manifold comprising an opening;
at least two parallel connecting channels, a first connecting channel and a second connecting channel, connected to the manifold; and
further characterized by a flow control structure that comprises:
a flow control design wherein, in each of the at least two parallel connecting channels, 20% or more of the channel's length is characterized by a constant crosssectional area, and 80% or less of the channel's length is characterized by a cross-sectional area reduced in size (relative to the 20% or more of the channel's length that is characterized by a constant cross-sectional area); and
wherein the first connecting channel has a longer length of constant crosssectional area than does the second connecting channel.
9. The chemical processing device of claim 8 wherein the manifold is a header manifold; and wherein the connecting channels are microchannels.
10. The chemical processing device of claim 9 wherein the length of constant crosssectional area in each of the at least two parallel connecting channels is contiguous and straight.
11. The chemical processing device of claim 10 wherein the length of reduced crosssectional area in each of the at least two parallel connecting channels is contiguous and straight.
12. The chemical processing device of claim 11 wherein the first connecting channel and the second connecting channel have substantially constant widths.
13. The chemical processing device of claim 9 wherein the length of reduced crosssectional area in each of the at least two parallel connecting channels is contiguous and straight.
14. The chemical processing device of claim 9 further comprising a submanifold;
wherein the connecting channels are connected to the submanifold.
15. The chemical processing device of claim 8 possessing a Q factor (Q 1 ) of 10% or less.
16. A chemical reactor, comprising:
at least two parallel connecting channels, a first connecting channel and a second connecting channel, connected to a manifold;
wherein a portion of the first connecting channel and a portion of the second connecting channel contain catalyst;
wherein the catalystcontaining portion of the first connecting channel and the catalystcontaining portion of the second connecting channel have equal and constant cross-sectional areas; and
wherein the first connecting channel has a first length of reduced crosssectional area and the second connecting channel has a second length of reduced crosssectional area; wherein the first length is less than the second length.
17. The chemical reactor of claim 16 wherein the manifold is a header manifold.
18. The chemical reactor of claim 16 wherein the connecting channels are microchannels.
19. The chemical reactor of claim 18 wherein the first connecting channel and the second connecting channel have substantially constant widths.
20. A chemical processing device comprising:
a manifold comprising an opening;
at least two parallel connecting channels, a first connecting channel and a second connecting channel, connected to the manifold; and
further characterized by a flow control structure that comprises:
a flow straightener connected to the manifold opening; and
a flow distribution section connecting the flow straightener and the parallel connecting channels;
wherein the flow distribution section comprises a cross sectional area that is greater than the cross sectional area of the flow straightener; and
further wherein the device comprises a characteristic Q factor (Q 1 ) of 10% or less.
21. The chemical processing device of claim 20
wherein the flow straightener has a length to hydraulic diameter (L fs /D h ) of at least 5 and a cross sectional area; and comprising a characteristic Q factor (Q 1 ) of 0.5 to 5%.