U.S. patent application number 14/014475 was filed with the patent office on 2015-03-05 for heat transfer unit for process fluids.
This patent application is currently assigned to UOP LLC. The applicant listed for this patent is UOP LLC. Invention is credited to William M. Hartman, Mark Lebrun, Keyur Y. Pandya, Michael S. Sandacz, David A. Wegerer.
Application Number | 20150060034 14/014475 |
Document ID | / |
Family ID | 52581511 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150060034 |
Kind Code |
A1 |
Pandya; Keyur Y. ; et
al. |
March 5, 2015 |
HEAT TRANSFER UNIT FOR PROCESS FLUIDS
Abstract
A heat transfer unit includes an inlet manifold; an outlet
manifold spaced from the inlet manifold; and a plurality of
conduits coupling the inlet manifold to the outlet manifold,
wherein at least on the conduits is coupled to the outlet manifold
at an oblique angle. In one form, the conduit includes a L-Coil. In
another form, the conduit includes a D-Coil. In another form, the
conduit includes a coil having two or more C-shaped sections. Each
conduit includes a section arranged in an interior space of a
heater box, and at least one heater is arranged in the interior
space of the heater box.
Inventors: |
Pandya; Keyur Y.; (Katy,
TX) ; Wegerer; David A.; (Lisle, IL) ;
Sandacz; Michael S.; (Glen Ellyn, IL) ; Hartman;
William M.; (Des Plaines, IL) ; Lebrun; Mark;
(Schaumburg, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UOP LLC |
Des Plaines |
IL |
US |
|
|
Assignee: |
UOP LLC
Des Plaines
IL
|
Family ID: |
52581511 |
Appl. No.: |
14/014475 |
Filed: |
August 30, 2013 |
Current U.S.
Class: |
165/175 |
Current CPC
Class: |
F28F 21/083 20130101;
F28D 1/0475 20130101; F28F 2275/06 20130101; F28D 2021/0022
20130101; F28D 1/047 20130101 |
Class at
Publication: |
165/175 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Claims
1. A heat transfer unit for process fluids, the heat transfer unit
comprising: an inlet manifold; an outlet manifold spaced from the
inlet manifold; and a plurality of conduits coupling the inlet
manifold to the outlet manifold, wherein at least one of the
conduits is coupled to the outlet manifold at an oblique angle.
2. The heat transfer unit of claim 1, wherein at least one of the
conduits includes a L-Coil.
3. The heat transfer unit of claim 1, wherein at least one of the
conduits includes a D-Coil.
4. The heat transfer unit of claim 1, wherein at least one of the
conduits includes a coil having a plurality of generally C-shaped
sections.
5. The heat transfer unit of claim 1, wherein at least one of the
conduits is coupled to the outlet manifold at an angle between
about five and eighty-five degrees.
6. The heat transfer unit of claim 1, wherein at least one of the
conduits is coupled to the outlet manifold at an angle between
about thirty and sixty degrees.
7. The heat transfer unit of claim 1, wherein each of the conduits
is coupled to the outlet manifold at an oblique angle.
8. The heat transfer unit of claim 1, wherein each conduit includes
a section arranged in an interior space of a heater box and wherein
at least one heater is arranged in the interior space of the heater
box.
9. An L-Coil heat transfer unit for process fluids, the L-Coil heat
transfer unit comprising: an inlet manifold; an outlet manifold
spaced from the inlet manifold; and an L-Coil coupled between the
inlet manifold and the outlet manifold, the L-Coil including a
horizontal leg and a vertical leg, the horizontal leg coupled to
the outlet manifold at an oblique angle such that a flow aperture
formed therebetween defines an oblong profile.
10. The L-Coil heat transfer unit of claim 9, wherein a plurality
of L-Coils are coupled to the outlet manifold at an oblique
angle.
11. The L-Coil heat transfer unit of claim 9, wherein the L-Coil is
arranged at between about a thirty and sixty degree angle relative
to the outlet manifold.
12. The L-Coil heat transfer unit of claim 9, wherein the L-Coil is
arranged at between about a five and eighty-five degree angle
relative to the outlet manifold.
13. The L-Coil heat transfer unit of claim 9, further comprising a
heater arranged substantially adjacent a bottom of the L-Coil heat
transfer unit.
14. The L-Coil heat transfer unit of claim 9, wherein the L-Coil
includes a section arranged in an interior space of a heater
box.
15. A D-Coil heat transfer unit for process fluids, the D-Coil heat
transfer unit comprising: an inlet manifold; an outlet manifold
spaced from the inlet manifold; and a D-Coil coupled between the
inlet manifold and the outlet manifold, the D-Coil including an
inlet section and an outlet section, the inlet section coupled to
the inlet manifold at an oblique angle, the outlet section coupled
to the outlet manifold at an oblique angle.
16. The D-Coil heat transfer unit of claim 15, wherein a flow
aperture formed between the outlet section and the outlet manifold
defines an oblong profile.
17. The D-Coil heat transfer unit of claim 15, wherein a plurality
of D-Coils are coupled to the inlet manifold at an oblique angle
and are coupled to the outlet manifold at an oblique angle.
18. The D-Coil heat transfer unit of claim 15, wherein the inlet
section is arranged at between about a thirty and sixty degree
angle relative to the inlet manifold, and wherein the outlet
section is arranged at between about a thirty and sixty degree
angle relative to the outlet manifold.
19. The D-Coil heat transfer unit of claim 15, wherein the D-Coil
includes a section arranged in an interior space of a heater
box.
20. The D-Coil heat transfer unit of claim 19, wherein at least one
heater is arranged in the interior space of the heater box.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The disclosure relates to a low pressure drop heat transfer
unit for process fluids.
[0003] 2. Description of the Related Art
[0004] Various catalytic conversion processes are known in the
petrochemical industry. For example, the catalytic reforming of a
hydrocarbon feedstream (e.g., a naphtha feedstream) to produce
aromatics (e.g., benzene, toluene, and xylenes) is described in
U.S. Patent Application Publication Nos. 2012/0277501,
2012/0277502, 2012/0277503, 2012/0277504, and 2012/0277505. The
catalytic dehydrogenation of a paraffin stream to yield olefins is
described in U.S. Pat. No. 8,282,887.
[0005] Catalytic reforming and catalytic dehydrogenation processes
are endothermic and therefore, heat must be added to maintain the
temperature of the reactions. U.S. Patent Application Publication
No. 2012/0275974 describes the use of interbed heaters to maintain
the temperature of reaction in the catalytic reactor of a reforming
process. Example heaters for process fluids can also be found in
U.S. Pat. Nos. 8,176,974 and 7,954,544.
[0006] Aromatics yield from a catalytic reforming unit and olefin
yield from a catalytic dehydrogenation unit increase, while yield
of undesirable products from competing cracking reactions
decreases, with lessening operating pressure. Thus, it may be
advantageous to minimize reaction zone operating pressure.
[0007] The hot residence time of a process stream before the
product stream leaves a reactor (also known as hot volume) can also
be critical to the catalytic selectivity to desired products for
thermally sensitive processes such as catalytic reforming and
catalytic dehydrogenation. Hot residence time reduction can be
critical in reactor circuit non-catalyst volumes in order to
prevent yield loss (aromatics or olefins) from competing thermal
cracking reactions.
[0008] Thus, the design of heaters used in catalytic reforming and
catalytic dehydrogenation processes to heat the feed upstream of
each reactor can be guided by two criteria, pressure drop and hot
residence time. While the overall low operating pressure benefits
the yields from the processes, it is more beneficial to use the
available pressure drop diligently in a reactor circuit. The use of
the available pressure drop further upstream in the reactor circuit
is least detrimental. The use of higher pressure drop further
upstream in the reactor circuit reduces yields to a lesser extent.
However, it reduces the hot residence time (thus thermal cracking)
in the upstream heaters where the process streams are often more
susceptible to thermal cracking than in the downstream heaters.
[0009] Thermal expansion and contraction in heater coils is yet
another design consideration. Specifically, the heater coils must
be able to withstand high process temperatures and metallurgical
changes and mechanical stress.
[0010] Therefore, what is needed is an improved heat transfer unit
for process fluids wherein the heat transfer unit provides low
pressure drop but also the flexibility to withstand thermal
expansion/contraction in the heater coils.
SUMMARY OF THE INVENTION
[0011] The foregoing needs are met by a heat transfer unit for
process fluids. The heat transfer unit includes an inlet manifold;
an outlet manifold spaced from the inlet manifold; and a plurality
of conduits coupling the inlet manifold to the outlet manifold,
wherein at least one of the conduits is coupled to the outlet
manifold at an oblique angle.
[0012] In one version of the heat transfer unit, at least one of
the conduits includes a L-Coil.
[0013] In another version of the heat transfer unit, at least one
of the conduits includes a D-Coil.
[0014] In another version of the heat transfer unit, at least one
of the conduits includes a coil having a plurality of generally
C-shaped sections.
[0015] In another version of the heat transfer unit, at least one
of the conduits is coupled to the outlet manifold at an angle
between about five and eighty-five degrees.
[0016] In another version of the heat transfer unit, at least one
of the conduits is coupled to the outlet manifold at an angle
between about thirty and sixty degrees.
[0017] In another version of the heat transfer unit, each of the
conduits is coupled to the outlet manifold at an oblique angle.
[0018] In another version of the heat transfer unit, each conduit
includes a section arranged in an interior space of a heater box
and wherein at least one heater is arranged in the interior space
of the heater box.
[0019] In another aspect, the invention provides an L-Coil heat
transfer unit for process fluids. The L-Coil heat transfer unit
includes an inlet manifold; an outlet manifold spaced from the
inlet manifold; and an L-Coil coupled between the inlet manifold
and the outlet manifold. The L-Coil includes a horizontal leg and a
vertical leg, wherein the horizontal leg is coupled to the outlet
manifold at an oblique angle such that a flow aperture formed
therebetween defines an oblong profile.
[0020] In one version of the L-Coil heat transfer unit, a plurality
of L-Coils are coupled to the outlet manifold at an oblique
angle.
[0021] In another version of the L-Coil heat transfer unit, the
L-Coil is arranged at between about a thirty and sixty degree angle
relative to the outlet manifold.
[0022] In another version of the L-Coil heat transfer unit, the
L-Coil is arranged at between about a five and eighty-five degree
angle relative to the outlet manifold.
[0023] The L-Coil heat transfer unit can further comprise a heater
arranged substantially adjacent a bottom of the L-Coil heat
transfer unit.
[0024] The L-Coil heat transfer unit can include a section arranged
in an interior space of a heater box.
[0025] In another aspect, the invention provides a D-Coil heat
transfer unit for process fluids. The D-Coil heat transfer unit
includes an inlet manifold; an outlet manifold spaced from the
inlet manifold; and a D-Coil coupled between the inlet manifold and
the outlet manifold, The D-Coil includes an inlet section and an
outlet section, and the inlet section is coupled to the inlet
manifold at an oblique angle, and the outlet section is coupled to
the outlet manifold at an oblique angle.
[0026] In one version of the D-Coil heat transfer unit, a flow
aperture formed between the outlet section and the outlet manifold
defines an oblong profile.
[0027] In another version of the D-Coil heat transfer unit, a
plurality of D-Coils are coupled to the inlet manifold at an
oblique angle and are coupled to the outlet manifold at an oblique
angle.
[0028] In another version of the D-Coil heat transfer unit, the
inlet section is arranged at between about a thirty and sixty
degree angle relative to the inlet manifold, and the outlet section
is arranged at between about a thirty and sixty degree angle
relative to the outlet manifold.
[0029] In another version of the D-Coil heat transfer unit, the
D-Coil includes a section arranged in an interior space of a heater
box. At least one heater can be arranged in the interior space of
the heater box.
[0030] In a low pressure drop heater design, the heater manifold
may account for close to 50% of the total pressure heater pressure
drop. The manifold pressure drop is mainly due to the entrance and
exit frictional losses from heater tubes to the heater outlet and
inlet.
[0031] The invention provides a heat transfer unit with an L-coil
design that decreases pressure drop. In one non-limiting example of
the heat transfer unit, an angled entrance to the heater outlet
manifold is used with the L-coil design. An angled entrance results
in an elliptical opening into the manifold. This lowers the inlet
velocity and the velocity is in the same direction as the process
fluid flow resulting in an additional decrease in a pressure drop.
An angled inlet into the heater outlet manifold also provides a
longer horizontal arm in an L-heater coil. This in turn gives more
flexibility to the heater coil for vertical compression and
tension. A longer horizontal arm of the L-Coil can provide better
flexibility in vertical movements.
[0032] The invention also provides a heat transfer unit with a
D-Coil to integrate the benefits for low pressure drop design with
an improved flexibility. A D-coil achieves an added reduction in
pressure drop by having an angled entry into and exit from, inlet
and outlet manifolds, respectively. In addition, a D-Coil provides
a better flexibility for vertical movements in a heater coil.
[0033] The invention demonstrates that an angled connection from
heater conduits to the manifold is preferably used and more
preferably, an angled connection is used at an outlet manifold
connection. This provides pressure drop reduction due to a bigger
opening at the connection (thus lower frictional loss) and less
turbulence (via same flow direction) with more flexibility for
vertical movements. The pressure drop reduction by angled
connection may be more at the outlet manifold connection than the
inlet connection due to higher designed velocity at the outlet. The
pressure reduction benefit can be more prominent in the low
pressure drop heater design. The design can also be used for higher
pressure drop heater designs. However, yield benefits from reduced
heater drop may be less.
[0034] It is therefore an advantage of the invention to provide a
low pressure drop heat transfer unit for process fluids.
[0035] It is another advantage of the invention to provide a heat
transfer unit for process fluids in a process where pressure drop
affects product yields.
[0036] These and other features, aspects, and advantages of the
present invention will become better understood upon consideration
of the following detailed description, drawings, and appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is an end view of a prior art U-Coil heat transfer
unit.
[0038] FIG. 2 is a perspective view of the U-Coil heat transfer
unit of FIG. 1.
[0039] FIG. 3 is a perspective view of a prior art L-Coil heat
transfer unit.
[0040] FIG. 4 is a side view of the L-Coil heat transfer unit of
FIG. 3.
[0041] FIG. 5 is an end view of the L-Coil heat transfer unit of
FIG. 3.
[0042] FIG. 6 is a top view of the L-Coil heat transfer unit of
FIG. 3.
[0043] FIG. 7 is a side view of an outlet manifold of the L-Coil
heat transfer unit of FIG. 3.
[0044] FIG. 8 is a perspective view of an L-Coil heat transfer unit
according to one embodiment of the invention.
[0045] FIG. 9 is a side view of the L-Coil heat transfer unit of
FIG. 8.
[0046] FIG. 10 is an end view of the L-Coil heat transfer unit of
FIG. 8.
[0047] FIG. 11 is a top view of the L-Coil heat transfer unit of
FIG. 8.
[0048] FIG. 12 is a side view of an outlet manifold of the L-Coil
heat transfer unit of FIG. 8.
[0049] FIG. 13 is a perspective view of an L-Coil heat transfer
unit according to one embodiment of the invention.
[0050] FIG. 14 is a side view of the L-Coil heat transfer unit of
FIG. 13.
[0051] FIG. 15 is an end view of the L-Coil heat transfer unit of
FIG. 13.
[0052] FIG. 16 is a top view of the L-Coil heat transfer unit of
FIG. 13.
[0053] FIG. 17 is a perspective view of an L-Coil heat transfer
unit according to one embodiment of the invention.
[0054] FIG. 18 is a side view of the L-Coil heat transfer unit of
FIG. 17.
[0055] FIG. 19 is an end view of the L-Coil heat transfer unit of
FIG. 17.
[0056] FIG. 20 is a top view of the L-Coil heat transfer unit of
FIG. 17.
[0057] FIG. 21 is a perspective view of a D-Coil heat transfer unit
according to one embodiment of the invention.
[0058] FIG. 22 is a side view of the D-Coil heat transfer unit of
FIG. 21.
[0059] FIG. 23 is an end view of the D-Coil heat transfer unit of
FIG. 21.
[0060] FIG. 24 is a top view of the L-Coil heat transfer unit of
FIG. 21.
[0061] FIG. 25 is a perspective view of a D-Coil heat transfer unit
according to one embodiment of the invention.
[0062] FIG. 26 is a side view of the D-Coil heat transfer unit of
FIG. 25.
[0063] FIG. 27 is an end view of the D-Coil heat transfer unit of
FIG. 25.
[0064] FIG. 28 is a top view of the L-Coil heat transfer unit of
FIG. 25.
[0065] FIG. 29 is a side view of a Triple C-Coil heat transfer unit
according to one embodiment of the invention.
[0066] Like reference numerals will be used to refer to like parts
from Figure to Figure in the following description of the
drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0067] Catalytic reactor systems may use U-Coil heaters for heating
fresh feed and reheating feed between reactors. A U-Coil style
heater may be desirable due to low process side pressure drop. An
example U-Coil style heat transfer unit 10 is shown in FIGS. 1 and
2 and includes an inlet manifold 14, an outlet manifold 18, a
heater box 19, and a plurality of U-coils 22 arranged for fluid
communication therebetween. A number of burners or heaters 26 are
arranged adjacent the axial ends of the manifolds 14, 18. The coils
in this embodiment and the other embodiments described herein may
be formed from a stainless steel (e.g., an austenitic 300 series
stainless steel such as 347) or a steel such as 9-Chrome-Moly
Steel.
[0068] Alternatively, catalytic reactor systems may use L-Coil
heaters for heating fresh feed and reheating feed between reactors.
An example L-Coil style heat transfer unit 30 is shown in FIGS. 3-7
and includes an inlet manifold 34, an outlet manifold 38, a heater
box 39, and a plurality of L-coils 42 arranged for fluid
communication therebetween. FIG. 7 shows apertures 46 arranged in
the outlet manifold 38 where the outlet manifold 38 couples with
the L-Coils 42. As clearly shown in FIG. 7, in this arrangement the
apertures 46 are substantially circular.
[0069] FIGS. 8-12 show an L-Coil heat transfer unit 50 according to
one aspect of the invention. The L-Coil heat transfer unit 50
includes an inlet manifold 54 arranged to receive a process fluid,
an outlet manifold 58 arranged to provide the process fluid to a
downstream location, a heater box 59, and a plurality of L-Coils 62
arranged therebetween.
[0070] The L-Coils 62 are preferably welded to the inlet manifold
54 and the outlet manifold 58 to provide a hermetic seal. As is
clearly visible in FIG. 11, the L-Coils 62 are arranged at an
oblique angle relative to a longitudinal axis A of the outlet
manifold 58. As shown in FIGS. 3-7, the current state-of-the-art is
to have L-Coils arranged perpendicular to an outlet manifold (i.e.,
arranged at a ninety-degree angle (90.degree.)). In a preferred
embodiment, the L-Coils 62 are rotated relative to the longitudinal
axis A by about forty-five degrees (45.degree.). In other
embodiments, the L-Coils 62 are rotated relative to the
longitudinal axis A by between about thirty and sixty degrees
(30-60.degree.). In still other embodiments, the L-Coils 62 are
rotated relative to the longitudinal axis A by between about twenty
and 70 degrees (20-70.degree.). In still other embodiments, the
L-Coils 62 are rotated relative to the longitudinal axis A by
between about five and eighty-five degrees (5-85.degree.).
[0071] As shown in FIG. 10, the inlet manifold 54 is horizontally
spaced from the outlet manifold 58 by a horizontal distance.
Additionally, each L-Coil 62 includes a horizontal leg 66 and a
vertical leg 70. Non-limiting example length ranges for the
horizontal leg 66 are 0.30 to 7.62 meters (1-25 feet), or 0.61 to
6.10 meters (2-20 feet), or 1.52 to 4.57 meters (5-15 feet).
Non-limiting example length ranges for the vertical leg 70 are 6.10
to 24.38 meters (20-80 feet), or 9.14 to 21.34 meters (30-70 feet),
or 12.19 to 18.29 meters (40-60 feet), or 13.72 to 16.76 meters
(45-55 feet). The oblique arrangement of the L-Coils 62 provides a
longer horizontal leg 66 relative to the horizontal distance
between the inlet manifold 54 and the outlet manifold 58 as
compared with a perpendicular arrangement. This longer horizontal
leg 66 allows for more flexibility in the system for better
response to thermal and mechanical stresses.
[0072] Turning to FIG. 12, the outlet manifold 58 is shown removed
from the L-Coil heat transfer unit 50. L-Coil outlet apertures 74
are clearly visible and provide an oval or oblong or elliptical
communication pathway between the L-Coils 62 and the outlet
manifold 58. The L-Coil outlet apertures 74 have a larger sectional
area as compared to the apertures 46 shown in FIG. 7.
[0073] In one embodiment, the length of the inlet manifold 54 and
outlet manifold 58 in the longitudinal direction is about fifteen
meters (about 50 feet) or more. In other embodiments, the
installation may be smaller or larger, as desired. The L-Coils 62
may be spaced apart by about fifty centimeters (about 10 feet). In
other embodiments, more or less spacing may be desirable. The
L-Coil heat transfer unit 50 may include up to about
eighteen-hundred (1800) L-Coils 62. In other embodiments, the
L-Coil heat transfer unit 50 may include more or less L-Coils 62,
as desired.
[0074] An additional feature of the L-Coil heat transfer unit 50 is
the ability to position a burner 78 in a variety of locations and
arrangements. As shown in FIG. 10, the burner 78 may be arranged
near the inlet manifold 54 at the bottom of the heater box 59 and
arranged under the L-Coils 62. The burner 78 may extend the full
longitudinal length of the L-Coil heat transfer unit 50. In other
arrangements, two or more burners 78 may be used (see FIG. 15) and
may be arranged elevated above the inlet manifold 54, arranged only
at one or two ends of the L-Coil heat transfer unit 50, or arranged
differently, as desired. The L-Coil heat transfer unit 50 provides
a significant advantage in the flexibility of how the L-Coils 62
are heated as compared to prior art U-Coil designs wherein hot
spots are a significant concern and inhibit the use of burners
arranged near the floor or inlet manifold 54. This flexibility will
be readily appreciated by those skilled in the art.
[0075] The L-Coil heat transfer unit 50 provides an advantageous
fluid flow pattern (shown in dash lines in FIG. 8) that reduces the
fluid friction and therefore reduces the pressure drop through the
L-Coil heat transfer unit 50 compared to other heat transfer
solutions. In other embodiments, other flow patterns are feasible.
For example, the inlet manifold 54 flow may originate on the left
(as shown in FIG. 8), or the outlet manifold 58 and the inlet
manifold 54 may be switched such that fluid flow is substantially
reversed from what is shown.
[0076] Turning now to FIGS. 13-16, another L-Coil heat transfer
unit 50' is shown. The L-Coil heat transfer unit 50' is
substantially similar to the L-Coil heat transfer unit 50 but
includes a larger horizontal spacing between an inlet manifold 54'
and an outlet manifold 58' and a correspondingly longer horizontal
leg 66' on each L-Coil 62'. All components of the L-Coil heat
transfer unit 50' have been numbered similar to the L-Coil heat
transfer unit 50 with prime numbers. An increased horizontal leg
66' length provides an L-Coil 62' with more flexibility with
respect to thermal and mechanical stresses.
[0077] Turning now to FIGS. 17-20, another L-Coil heat transfer
unit 50'' is shown. The L-Coil heat transfer unit 50'' is
substantially similar to the L-Coil heat transfer unit 50 but
includes a larger horizontal spacing between an inlet manifold 54''
and an outlet manifold 58''', and a correspondingly longer
horizontal leg 66'' on each L-Coil 62''. All components of the
L-Coil heat transfer unit 50'' have been numbered similar to the
L-Coil heat transfer unit 50 with prime numbers. An increased
horizontal leg 66'' length provides an L-Coil 62'' with more
flexibility with respect to thermal and mechanical stresses.
[0078] Turning to FIGS. 21-24, a D-Coil heat transfer unit 100
includes an inlet manifold 104, and outlet manifold 108, a heater
box 109, and a plurality of D-Coils 112 arranged therebetween. The
distance between the inlet manifold 104 and the outlet manifold 108
may be in the range of 6.10 to 24.38 meters (20-80 feet), or 9.14
to 21.34 meters (30-70 feet), or 12.19 to 18.29 meters (40-60
feet), or 13.72 to 16.76 meters (45-55 feet). Each D-Coil 112
includes an oblique inlet section 116, an outlet section 122, and a
transfer section 124 therebetween. Non-limiting example length
ranges for the inlet section 116 and the outlet section 122 are
0.30 to 7.62 meters (1-25 feet), or 0.61 to 6.10 meters (2-20
feet), or 1.52 to 4.57 meters (5-15 feet). Non-limiting example
length ranges for the transfer section 124 are 9.14 to 13.72 meters
(30-45 feet), or 12.19 to 14.68 meters (40-48 feet).
[0079] The illustrated inlet section 116 is arranged at an oblique
angle relative to a longitudinal axis of the inlet manifold 104. In
the illustrated embodiment, the inlet section 116 is arranged at
about a forty-five degree angle (45.degree.) relative to the
longitudinal axis of the inlet manifold 104. In other embodiments,
the inlet section 116 is arranged at between about thirty and sixty
degrees (30-60.degree.) relative to the longitudinal axis of the
inlet manifold 104. In still other embodiments, the inlet section
116 is arranged at between about twenty and seventy degrees
(20-70.degree.) relative to the longitudinal axis of the inlet
manifold 104. In still other embodiments, the inlet section 116 is
arranged at between about five and eighty-five degrees
(5-85.degree.) relative to the longitudinal axis of the inlet
manifold 104.
[0080] The outlet section 122 is arranged at an oblique angle
relative to a longitudinal axis of the outlet manifold 108. In the
illustrated embodiment, the outlet section 122 is arranged at about
a forty-five degree angle (45.degree.) relative to the longitudinal
axis of the outlet manifold 108. In other embodiments, the outlet
section 122 is arranged at between about thirty and sixty degrees
(30-60.degree.) relative to the longitudinal axis of the outlet
manifold 108. In other embodiments, the outlet section 122 is
arranged at between about twenty and seventy degrees
(20-70.degree.) relative to the longitudinal axis of the outlet
manifold 108. In still other embodiments, the outlet section 122 is
arranged at between about five and eighty-five degrees
(5-85.degree.) relative to the longitudinal axis of the outlet
manifold 108.
[0081] As a result of the oblique relation between the D-Coils 112
and the inlet and outlet manifolds 104, 108, the flow apertures
formed at the junction between the D-Coils 112 and the inlet and
outlet manifolds 104, 108 are oval or oblong or elliptical as
described above with respect to apertures 74.
[0082] The D-Coil heat transfer unit 100 provides an advantageous
fluid flow pattern (shown in dash lines in FIG. 22) that reduces
the fluid friction and therefore reduces the pressure drop through
the D-Coil heat transfer unit 100 compared to other heat transfer
solutions. In other embodiments, other flow patterns are
feasible.
[0083] FIGS. 25-28 show a D-Coil heat transfer unit 100' similar to
the D-Coil heat transfer unit 100 and is labeled with prime
numbers. The inlet sections 116' and the outlet sections 122' are
of decreased length compared to the inlet sections 116 and the
outlet sections 122 in the embodiment of FIGS. 21-24.
[0084] Turning to FIG. 29, a Triple C-Coil heat transfer unit 200
includes an inlet manifold 204, an outlet manifold 208, a heater
box, and a plurality of Triple C-Coils 210 arranged therebetween.
The distance between the inlet manifold 204 and the outlet manifold
208 may be in the range of 6.10 to 24.38 meters (20-80 feet), or
9.14 to 21.34 meters (30-70 feet), or 12.19 to 18.29 meters (40-60
feet), or 13.72 to 16.76 meters (45-55 feet). Each Triple C-Coil
210 includes a generally C-shaped inlet section 216, a generally
C-shaped outlet section 222, and a generally C-shaped transfer
section 212 therebetween.
[0085] The illustrated inlet section 216 is arranged at an oblique
angle relative to a longitudinal axis of the inlet manifold 204. In
the illustrated embodiment, the junction of the inlet section 216
is arranged at about a forty-five degree angle (45.degree.)
relative to the longitudinal axis of the inlet manifold 204. See
angle C in FIG. 29. In other embodiments, the junction of the inlet
section 216 is arranged at between about thirty and sixty degrees
(30-60.degree.) relative to the longitudinal axis of the inlet
manifold 204. In still other embodiments, the junction of the inlet
section 216 is arranged at between about twenty and seventy degrees
(20-70.degree.) relative to the longitudinal axis of the inlet
manifold 204. In still other embodiments, the junction of the inlet
section 216 is arranged at between about five and eighty-five
degrees (5-85.degree.) relative to the longitudinal axis of the
inlet manifold 204.
[0086] The outlet section 222 is arranged at an oblique angle
relative to a longitudinal axis of the outlet manifold 208. In the
illustrated embodiment, the junction of the outlet section 222 is
arranged at about a forty-five degree angle (45.degree.) relative
to the longitudinal axis of the outlet manifold 208. See angle D in
FIG. 29. In other embodiments, the junction of the outlet section
222 is arranged at between about thirty and sixty degrees
(30-60.degree.) relative to the longitudinal axis of the outlet
manifold 208. In other embodiments, the junction of the outlet
section 222 is arranged at between about twenty and seventy degrees
(20-70.degree.) relative to the longitudinal axis of the outlet
manifold 208. In still other embodiments, the junction of the
outlet section 222 is arranged at between about five and
eighty-five degrees (5-85.degree.) relative to the longitudinal
axis of the outlet manifold 208.
[0087] As a result of the oblique relation between the Triple
C-Coils 210 and the inlet and outlet manifolds 204, 208, the flow
apertures formed at the junction between the Triple C-Coils 210 and
the inlet and outlet manifolds 204, 208 are oval or oblong or
elliptical as described above with respect to apertures 74.
[0088] The Triple C-Coil heat transfer unit 200 provides an
advantageous fluid flow pattern that reduces the fluid friction and
therefore reduces the pressure drop through the Triple C-Coil heat
transfer unit 200 compared to other heat transfer solutions. In
other embodiments, other flow patterns are feasible.
[0089] In one aspect, the invention provides a catalytic
dehydrogenation process that includes passing a hydrocarbon feed
stream through any of heat transfer units 10, 30, 50, 50', 50'',
100, 100', 200, and then passing the heated hydrocarbon feed stream
and a catalyst into a reactor thereby creating a product
stream.
[0090] In another aspect, the invention provides, a catalytic
reforming process that includes passing a hydrocarbon feed stream
through any of heat transfer units 10, 30, 50, 50', 50'', 100,
100', 200, and then passing the heated hydrocarbon feed stream and
a catalyst into a reactor thereby creating a product stream.
[0091] Thus, the invention provides a heat transfer unit for
process fluids. While use of the heat transfer unit is not limited
to any process, the heat transfer unit can be particularly
beneficial in heating process fluids in: (i) the catalytic
reforming of a hydrocarbon feedstream (e.g., a naphtha feedstream)
to produce aromatics (e.g., benzene, toluene and xylenes) (see,
e.g., U.S. Patent Application Publication Nos. 2012/0277501,
2012/0277502, 2012/0277503, 2012/0277504, and 2012/0277505); and
(ii) the catalytic dehydrogenation of a paraffin stream to yield
olefins (see, e.g., U.S. Pat. No. 8,282,887).
[0092] Although the invention has been described in considerable
detail with reference to certain embodiments, one skilled in the
art will appreciate that the present invention can be practiced by
other than the described embodiments, which have been presented for
purposes of illustration and not of limitation. Therefore, the
scope of the appended claims should not be limited to the
description of the embodiments contained herein.
* * * * *