U.S. patent application number 14/787643 was filed with the patent office on 2016-04-21 for falling film evaporator for power generation systems.
The applicant listed for this patent is UNITED TECHNOLOGIES CORPORATION. Invention is credited to Sean P. Breen, Jaeseon Lee, Ahmad M. Mahmoud.
Application Number | 20160108762 14/787643 |
Document ID | / |
Family ID | 51844111 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160108762 |
Kind Code |
A1 |
Mahmoud; Ahmad M. ; et
al. |
April 21, 2016 |
FALLING FILM EVAPORATOR FOR POWER GENERATION SYSTEMS
Abstract
A system (10) includes a condenser (12) with an inlet (22) and
an outlet (24), a pump (14) with an outlet (28) and with an inlet
(26) connected to the outlet (24) of the condenser (12), and an
evaporator (16). The evaporator (16) includes an inlet (30)
connected to the outlet (28) of the pump (14), an outlet (31),
evaporating tubes (38), and a fluid distribution system (33) for
spraying a fluid over the evaporating tubes (38). The system (10)
further includes a turbine (18) with an inlet (44) connected to the
outlet (31) of the evaporator (16), an outlet (48) connected to the
inlet (22) of the condenser (12), and a drive shaft (46). A
generator (20) is connected to the drive shaft (46) of the turbine
(18).
Inventors: |
Mahmoud; Ahmad M.; (Bolton,
CT) ; Lee; Jaeseon; (Galstonbury, CT) ; Breen;
Sean P.; (Holyoke, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNITED TECHNOLOGIES CORPORATION |
Hartford |
CT |
US |
|
|
Family ID: |
51844111 |
Appl. No.: |
14/787643 |
Filed: |
May 1, 2014 |
PCT Filed: |
May 1, 2014 |
PCT NO: |
PCT/US2014/036389 |
371 Date: |
October 28, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61818093 |
May 1, 2013 |
|
|
|
Current U.S.
Class: |
60/651 ;
60/671 |
Current CPC
Class: |
F01K 25/08 20130101;
F22B 9/10 20130101; F01K 25/10 20130101; F22G 7/02 20130101; F22B
27/165 20130101 |
International
Class: |
F01K 25/08 20060101
F01K025/08 |
Claims
1. A system comprising: a condenser with an inlet and an outlet; a
pump with an outlet and with an inlet connected to the outlet of
the condenser; an evaporator comprising: an inlet connected to the
outlet of the pump; an outlet; a plurality of evaporating tubes;
and a fluid distribution system for spraying a fluid over the
plurality of evaporating tubes; a turbine with an inlet connected
to the outlet of the evaporator, an outlet connected to the inlet
of the condenser, and a drive shaft; and a generator connected to
the drive shaft of the turbine.
2. The system of claim 1, wherein the system is a power generation
system.
3. The system of claim 1, wherein the fluid is a refrigerant.
4. The system of claim 3, wherein the refrigerant is a
hydrofluorocarbon, hydrocarbon, fluorinated ketone, fluorinated
ether, chloro-olefin, bromo-fluoro olefin, hydrofluoroolefin,
hydrofluoroolefin ether, hydrochlorofluoroolefin ether, linear
siloxane, or cyclic siloxane.
5. The system of claim 4, wherein the refrigerant is propane,
cyclopropane, isobutene, isobutane, n-butane, propylene, n-pentane,
isopentane, cyclopentane, R-134a, R-30, R-32, R-123, R-125, R-143a,
R-134, R-152a, R-161, R-1216, R-227ea, R-245fa, R-245cb, R-236ea,
R-236fa, R-365mfc, HT-55, R-43-10mee, HFE-7100, Novec-649, CF3I,
R-1234ye, R-1234yf, R-1234ze, R-1233zd(E), R-1233zd(Z),
R-1225ye(Z), R-1225ye(E), C5F9Cl, C5H2F10, R-1243zf, E-134a, E134,
E125, E143a, siloxane MM, dimethylether, or CO2.
6. The system of claim 1, wherein the evaporator further comprises
pool boiling tubes.
7. The system of claim 6, wherein the evaporator further comprises
a plurality of superheating tubes near the outlet of the evaporator
for heating the fluid evaporated by the plurality of evaporating
tubes and the plurality of pool boiling tubes.
8. The system of claim 7, wherein the plurality of superheating
tubes is next to the plurality of evaporating tubes below the fluid
distribution system.
9. The system of claim 7, wherein the plurality of superheating
tubes is above the fluid distribution system.
10. The system of claim 1, and further comprising a recirculation
pump for recirculating fluid from the evaporator to the inlet of
the evaporator.
11. The system of claim 10, wherein the evaporator further
comprises a plurality of superheating tubes near the outlet of the
evaporator for heating the fluid evaporated by the plurality of
evaporating tubes and the plurality of pool boiling tubes.
12. The system of claim 11, wherein the plurality of superheating
tubes is next to the plurality of evaporating tubes below the fluid
distribution system.
13. The system of claim 12, wherein the plurality of superheating
tubes is above the fluid distribution system.
14. A method of processing a fluid in a system, the method
comprising: condensing the fluid in a condenser; pumping the fluid
from the condenser into an evaporator; spraying the fluid from a
fluid distribution system in the evaporator to cover a plurality of
evaporating tubes in the evaporator; dripping an excess of the
fluid off of the plurality of evaporating tubes to form a pool in
the evaporator; evaporating the fluid from the plurality of
evaporating tubes; expanding the evaporated fluid in a turbine; and
producing power in a generator using the fluid expanded in the
turbine.
15. The method of claim 14, wherein the fluid is a refrigerant.
16. The method of claim 15, wherein the refrigerant is a
hydrofluorocarbon, hydrocarbon, fluorinated ketone, fluorinated
ether, chloro-olefin, bromo-fluoro olefin, hydrofluoroolefin,
hydrofluoroolefin ether, hydrochlorofluoroolefin ether, linear
siloxane, or cyclic siloxane.
17. The method of claim 16, wherein the refrigerant is propane,
cyclopropane, isobutene, isobutane, n-butane, propylene, n-pentane,
isopentane, cyclopentane, R-134a, R-30, R-32, R-123, R-125, R-143a,
R-134, R-152a, R-161, R-1216, R-227ea, R-245fa, R-245cb, R-236ea,
R-236fa, R-365mfc, HT-55, R-43-10mee, HFE-7100, Novec-649, CF3I,
R-1234ye, R-1234yf, R-1234ze, R-1233zd(E), R-1233zd(Z),
R-1225ye(Z), R-1225ye(E), C5F9Cl, C5H2F10, R-1243zf, E-134a, E134,
E125, E143a, siloxane MM, dimethylether, or CO2.
18. The method of claim 14, wherein evaporating the fluid further
comprises evaporating the fluid from the pool with a plurality of
pool boiling tubes.
19. The method of claim 18, and further comprising heating the
evaporated fluid with a plurality of superheating tubes prior to
expanding the evaporated fluid in the turbine.
20. The method of claim 14, and further comprising recirculating
the fluid from the pool in the evaporator back to the fluid
distribution system of the evaporator.
21. The method of claim 20, and further comprising heating the
evaporated fluid with a plurality of superheating tubes prior to
expanding the evaporated fluid in the turbine.
22. The method of claim 14, wherein the excess of fluid dripping
off of the plurality of evaporating tubes comprises between 15 and
25 percent of the fluid sprayed from the fluid distribution system.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims priority from U.S. Provisional
Application No. 61/818,093, filed May 1, 2013 for "FALLING FILM
EVAPORATOR FOR MIXED REFRIGERANTS" by Ahmad M. Mahmoud et al.
BACKGROUND
[0002] The present invention relates to power generation systems,
and more specifically relates to a system with an evaporator for
power generation systems.
[0003] The Organic Rankine Cycle (ORC) is commonly used as a power
generation system for low temperature resources such as geothermal,
solar thermal, biomass, and waste heat recovery. The primary
components of an ORC system include an expansion device, a
condenser, an evaporator/gas heater, and a motive pump.
Traditionally Organic Rankine Cycle systems employ flooded
evaporators, which use a shell and tube construction in order to
evaporate a pool of liquid to produce superheated vapor. In typical
flooded evaporators, a resource, such as hot water or hot fluid,
flows through tubes. In less conventional systems, a hot gas flows
through smoke tubes. The resource facilitates heat exchange between
a pool of liquid, usually a working fluid comprised of a
refrigerant, and the surface of the tubes to evaporate the liquid,
resulting in superheated vapor. To continue the cycle, the
superheated vapor exits the evaporator, expands in a turbine,
spinning a generator, which then produces electricity. Low pressure
and low temperature vapor exits the turbine and flows through a
condenser where a cooler medium, such as air or water, condenses
the vapor into liquid in a condenser. Liquid from the condenser is
then pumped back into the pool of the flooded evaporator to repeat
the cycle.
[0004] Flooded evaporators are disadvantageous for power generation
cycles in terms of cost, environmental impact, footprint, and
efficiency. Flooded evaporators require a significant amount of
refrigerant charge to cover enough tubes to maintain sufficient
heat transfer in order to evaporate the refrigerant liquid. In
order to control the degree of superheat in order to maintain
optimal turbine and system performance, a predetermined number of
tubes remain unwetted in order to superheat the vapor being
generated in the evaporator. The number of tubes that need to
remain wetted is still quite significant, requiring a significant
amount of refrigerant charge. Using a flooded evaporator,
particularly for systems that utilize hydrofluorocarbons or other
relevant working fluids, poses a significant cost concern due to
the significant initial refrigerant charge, as well as the charge
needed for maintenance and replenishment. Furthermore, due to
thermal stratification effects and distribution of refrigerant, the
refrigerant near the bottom of the evaporator requires a relatively
higher temperature in order to evaporate the liquid thereby making
the system less efficient.
SUMMARY
[0005] A system includes a condenser with an inlet and an outlet, a
pump with an outlet and with an inlet connected to the outlet of
the condenser, and an evaporator. The evaporator includes an inlet
connected to the outlet of the pump, an outlet, evaporating tubes,
and a fluid distribution system for spraying a fluid over the
evaporating tubes. The system further includes a turbine with an
inlet connected to the outlet of the evaporator, an outlet
connected to the inlet of the condenser, and a drive shaft. A
generator is connected to the drive shaft of the turbine.
[0006] In another embodiment, a method of processing a fluid
includes condensing the fluid in a condenser, pumping the fluid
from the condenser into an evaporator, and spraying the fluid from
a fluid distribution system in the evaporator to cover evaporating
tubes in the evaporator. The method further includes dripping an
excess of the fluid off of the evaporating tubes to form a pool in
the evaporator, evaporating the fluid from the evaporating tubes,
expanding the evaporated fluid in a turbine, and producing power in
a generator using the fluid expanded in the turbine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a flow schematic of the present invention.
[0008] FIG. 2 is a flow schematic including an alternate embodiment
evaporator of the present invention.
[0009] FIG. 3 is a cross section along line 3-3 in FIG. 2 of the
alternate embodiment evaporator of the present invention.
[0010] FIG. 4 is a cross section along line 3-3 in FIG. 2 of
another alternate embodiment evaporator of the present invention
without superheating tubes.
[0011] FIG. 5 is a flow schematic including another alternate
embodiment of the evaporator of the present invention with a
recirculation pump and without pool boiling tubes.
[0012] FIG. 6 is a cross section along line 6-6 in FIG. 5 of
another alternate embodiment evaporator of the present invention
with a recirculation pump, without pool boiling tubes, and without
super heating tubes.
DETAILED DESCRIPTION
[0013] The present invention utilizes a falling film evaporator to
achieve efficient heat transfer in power generation systems, such
as systems employing Organic Rankine Cycle (ORC) technology. The
falling film evaporator of the present invention may include a
falling film portion with evaporating tubes as well as a pool
boiling portion with pool boiling tubes for evaporating excess
refrigerant falling from the evaporating tubes. The falling film
evaporator of the present invention may include a recirculation
pump as an alternative to pool boiling tubes. The falling film
evaporator of the present invention may also include a means for
superheating to ensure optimal turbine and system performance. The
falling film evaporator design reduces refrigerant charge necessity
by 30%-70% as compared to a flooded evaporator. The falling film
evaporator of the present invention enhances heat transfer, reduces
cost, and reduces the size and footprint of state-of-the-art power
generation systems.
[0014] The fluid employed in the falling film evaporator of the
present invention may be a dry working fluid (not requiring
superheat) or a wet working fluid (requiring superheat). The fluid
may be a refrigerant, such as hydrofluorocarbons, hyrocarbons,
fluorinated ketones, fluorinated ethers, chloro- and bromo-fluoro
olefins, hydrofluoroolefins, hydrofluoroolefin ethers,
hydrochlorofluoroolefin ethers, and linear and/or cyclic siloxanes.
These compounds can be further defined as one or more of propane,
cyclopropane, isobutene, isobutane, n-butane, propylene, n-pentane,
isopentane, cyclopentane, R-134a, R-30, R-32, R-123, R-125, R-143a,
R-134, R-152a, R-161, R-1216, R-227ea, R-245fa, R-245cb, R-236ea,
R-236fa, R-365mfc, HT-55, R-43-10mee, HFE-7100, Novec-649, CF3I,
R-1234 (ye and yf), R-1234ze, R-1233 (zd(E) and zd(Z)), R-1225
(ye(Z) and ye(E)), C5F9Cl, C5H2F10, R-1243zf, E-134a, E134, E125,
E143a, siloxane MM, dimethylether, and CO2. Compounds may be
selected based on characteristics that can enhance system
performance, enhance heat transfer characteristics, provide fire
suppression, provide flame retardation, provide lubrication,
provide compound stabilization, provide corrosion inhibition, and
provide solubility compatibility, tracing, prognostics or
diagnostics.
[0015] FIG. 1 is a flow schematic of system 10 including condenser
12, pump 14, evaporator 16, turbine 18, and generator 20. Condenser
12 includes inlet 22 and outlet 24. Pump 14 includes inlet 26 and
outlet 28. Evaporator 16 may be a falling film evaporator and
consists of a shell through which superheating tubes 36,
evaporating tubes 38, and pool boiling tubes 42 pass horizontally
in tube bundles. Evaporator 16 also includes inlet 30, outlet 31,
outlet 32, distribution system 33 with spray manifold 34 and spray
nozzles 35, vapor lanes 37, and pool 40. Turbine 18 includes inlet
44 and outlet 48. Drive shaft 46 connects turbine 18 to generator
20.
[0016] System 10 may be an ORC system. System 10 processes a fluid
to produce power. The fluid may be a wet working fluid, which
requires superheat. The fluid enters evaporator 16 through inlet 30
using pump 14. Distribution system 33 uses spray nozzles 35
attached to spray manifold 34 to spray subcooled fluid at high
pressure over evaporating tubes 38. Distribution system 33 is
arranged in an overlaying relationship with the upper most level of
the top of evaporating tubes 38. Evaporating tubes 38 consist of
tube bundles which are positioned in a staggered manner under
distribution system 33 to maximize contact with the fluid sprayed
out of distribution system 33 onto the upper portion of evaporating
tubes 38. To begin the evaporation process, the first row of
evaporating tubes 38 is sprayed with subcooled fluid. Distribution
system 33 is designed such that the first row of evaporating tubes
38 is drenched and covered but not oversupplied with fluid,
starting the evaporation process. The fluid falls down subsequent
rows of evaporating tubes 38. The fluid falling off the last row of
evaporating tubes 38 collects and forms pool 40 at the bottom of
evaporator 16. A control system may be employed to ensure that no
dry-out occurs along the length and width of evaporating tubes
38.
[0017] In one embodiment, the fluid spray from distribution system
33 is controlled such that 15% of the fluid sprayed falls off the
last row of evaporating tubes 38, while the rest of the fluid
sprayed is evaporated by evaporating tubes 38. In an alternative
embodiment, distribution system 33 is controlled such that 20% of
the fluid sprayed falls off the last row of evaporating tubes 38.
In another alternative embodiment distribution system 33 is
controlled such that 25% of the fluid sprayed falls off the last
row of evaporating tubes 38. In other embodiments, a control system
is employed to vary the percentage of fluid falling off of the law
row of evaporating tubes 38 between 5% and 50%.
[0018] Pool 40 covers pool boiling tubes 42. Pool boiling tubes 42
cause the fluid in pool 40 to evaporate. Therefore, the saturated
vapor generated by evaporator 16 consists of fluid evaporated by
evaporating tubes 38 and pool boiling tubes 42. Superheating tubes
36 are located on both sides of evaporating tubes 38. The saturated
vapor travels along the periphery of evaporator 16 in vapor lanes
37, and when the saturated vapor reaches superheating tubes 36,
superheating tubes 36 increase the temperature of the saturated
vapor at a constant pressure, which results in favorable system
performance. Since the fluid in system 10 may be a wet working
fluid, superheating tubes 36 provide superheating to prevent liquid
droplets from forming when the fluid expands through turbine 18.
Superheating tubes 36 therefore ensure that the saturated vapor is
heated sufficiently to result in favorable and proper performance
of turbine 18.
[0019] Once the saturated vapor is superheated by superheating
tubes 36, superheated vapor exits evaporator 16 through outlets 31
and 32 and superheated vapor enters turbine 18 through inlet 44.
Turbine 18 expands superheated vapor spinning drive shaft 46, which
drives generator 20 to produce power. Turbine 18 may be
screw-shaped, axial, radial, or any other type of positive
displacement shape. Low pressure and low temperature vapor from
turbine 18 flows out through outlet 48 and into condenser 12
through inlet 22. In condenser 12, a cooler medium like air or
water flowing through condenser 12 condensers the vapor into
subcooled liquid. Subcooled liquid from condenser 12 exits through
outlet 24 and enters pump 14 through inlet 26. Pump 14 pumps
subcooled liquid through outlet 28 and into inlet 30 of evaporator
16. The cycle is subsequently repeated to continue to produce
power.
[0020] FIG. 2 is a flow schematic of an alternative embodiment of
the present invention, system 100, including condenser 112, pump
114, evaporator 116, turbine 118, and generator 120. Condenser 112
includes inlet 122 and outlet 124. Pump 114 includes inlet 126 and
outlet 128. Evaporator 116 consists of a shell through which
superheating tubes 136, evaporating tubes 138, and pool boiling
tubes 142 pass in tube bundles. Evaporator 116 also includes inlet
130, outlet 132, distribution system 133 with spray manifold 134
and spray nozzles 135, vapor lanes 137, and pool 140. Turbine 118
includes inlet 144 and outlet 148. Drive shaft 146 connects turbine
118 to generator 120.
[0021] System 100 may be an ORC system. System 100 processes a
fluid to produce power. The fluid may be a wet working fluid, which
requires superheat. The fluid enters evaporator 116 through inlet
130 using pump 114. Distribution system 133 uses spray nozzles 135
attached to spray manifold 134 to spray subcooled fluid at high
pressure over evaporating tubes 138. Distribution system 133 is
arranged in an overlaying relationship with the upper most level of
the top of evaporating tubes 138. Evaporating tubes 138 consist of
tube bundles which are positioned in a staggered manner under
distribution system 133 to maximize contact with the fluid sprayed
out of distribution system 133 onto the upper portion of
evaporating tubes 138. To begin the evaporation process, the first
row of evaporating tubes 138 is sprayed with subcooled fluid.
Distribution system 133 is designed such that the first row of
evaporating tubes 138 is drenched and covered but not oversupplied
with fluid, starting the evaporation process. The fluid falls down
subsequent rows of evaporating tubes 138. The fluid falling off the
last row of evaporating tubes 138 collects and forms pool 140 at
the bottom of evaporator 116. A control system may be employed to
ensure that no dry-out occurs along the length and width of
evaporating tubes 138.
[0022] In one embodiment, the fluid spray from spray manifold 134
is controlled such that 15% of the fluid sprayed falls off the last
row of evaporating tubes 138, and the rest of the fluid sprayed is
evaporated by evaporating tubes 138. In an alternative embodiment,
spray manifold 134 is controlled such that 20% of the fluid sprayed
falls off the last row of evaporating tubes 138. In another
alternative embodiment spray manifold 134 is controlled such that
25% of the fluid sprayed falls off the last row of evaporating
tubes 138. In other embodiments, a control system is employed to
vary the percentage of fluid falling off of the law row of
evaporating tubes 138 between 5% and 50%.
[0023] Pool 140 covers pool boiling tubes 142. Pool boiling tubes
142 cause the fluid in pool 140 to evaporate. Therefore, the
saturated vapor in evaporator 116 consists of fluid evaporated by
evaporating tubes 138 and pool boiling tubes 142. Superheating
tubes 136 are located above spray manifold 134. The saturated vapor
travels along the periphery of evaporator 116 in vapor lanes 137,
and when the saturated vapor reaches superheating tubes 136,
superheating tubes 136 increase the temperature of the saturated
vapor at a constant pressure, which results in favorable system
performance. Since the fluid in system 100 may be a wet working
fluid, superheating tubes 136 provide superheating to prevent
liquid droplets from forming when the fluid expands through turbine
118. Superheating tubes 136 therefore ensure that the saturated
vapor is heated sufficiently to result in favorable and proper
performance of turbine 118.
[0024] Once the saturated vapor is superheated by superheating
tubes 136, superheated vapor exits evaporator 116 through outlet
132 and superheated vapor enters turbine 118 through inlet 144.
Turbine 118 expands superheated vapor spinning drive shaft 146,
which drives generator 120 to produce power. Turbine 118 may be
screw-shaped, axial, radial, or any other type of positive
displacement shape. Low pressure and low temperature vapor from
turbine 118 flows out through outlet 148 and into condenser 112
through inlet 122. In condenser 112, a cooler medium like air or
water flowing through condenser 112 condensers the vapor into
subcooled liquid. Subcooled liquid from condenser 112 exits through
outlet 124 and enters pump 114 through inlet 126. Pump 114 pumps
subcooled liquid through outlet 128 and into inlet 130 of
evaporator 116. The cycle is subsequently repeated to continue to
produce power.
[0025] FIG. 3 is a cross section of evaporator 116 of system 100
along line 3-3 in FIG. 2. Evaporator 116 consists of a shell
through which superheating tubes 136, evaporating tubes 138, and
pool boiling tubes 142 pass in tube bundles. Evaporator 116 also
includes inlet 130, outlet 132, distribution system 133 with spray
manifold 134 and spray nozzles 135, pool 140, resource inlet 152,
resource inlet 154, resource outlet 156, and resource outlet
158.
[0026] Evaporator 116 is a two pass evaporator. During operation of
evaporator 116, a resource, such as hot water, enters superheating
tubes 136 through resource inlet 152, flows through superheating
tubes 136 and into evaporating tubes 138 (as shown by the flow
direction arrows), where the resource exits through resource outlet
156. The temperature of the resource is higher in superheating
tubes 136 than in evaporating tubes 138. A resource, such as hot
water, enters pool boiling tubes 142 through resource inlet 154,
flows through pool boiling tubes 142 into evaporating tubes 138 (as
shown by the flow direction arrows), where the resource exits
through resource outlet 158. The temperature of the resource is
higher in pool boiling tubes 142 than in evaporating tubes 138.
[0027] Subcooled liquid enters evaporator 116 through inlet 130.
Distribution system 133 uses spray nozzles 135 attached to spray
manifold 134 to spray subcooled fluid at high pressure over
evaporating tubes 138. The heat from the resource flowing through
evaporating tubes 138 allows the fluid to begin evaporating. The
fluid falls down subsequent rows of evaporating tubes 138. The
fluid falling off the last row of evaporating tubes 138 collects
and forms pool 140 at the bottom of evaporator 116. The heat from
the resource flowing through pool boiling tubes 142 causes the
fluid in pool 140 to evaporate. Therefore, the saturated vapor in
evaporator 116 consists of fluid evaporated by evaporating tubes
138 and pool boiling tubes 142. The saturated vapor travels up
through evaporator 116, and when the saturated vapor reaches
superheating tubes 136, the heat from the resource flowing through
superheating tubes 136 increases the temperature of the saturated
vapor at a constant pressure. Once the saturated vapor is
superheated by superheating tubes 136, superheated vapor exits
evaporator 116 through outlet 132.
[0028] FIG. 4 is a cross section of an alternative embodiment
evaporator, evaporator 216, of system 100 along line 3-3 in FIG. 2.
Evaporator 216 consists of a shell through which evaporating tubes
238 and pool boiling tubes 242 pass in tube bundles. Evaporator 116
also includes inlet 230, outlet 232, distribution system 233 with
spray manifold 234 and spray nozzles 235, pool 240, resource inlet
252, resource inlet 254, resource outlet 256, and resource outlet
258. The fluid processed with evaporator 216 may be a dry working
fluid, which does not require superheat. Therefore, evaporator 216
does not include superheating tubes.
[0029] During operation of evaporator 216, a resource, such as hot
water, flows into evaporating tubes 238 through resource inlet 252.
The resource continues to flow through additional evaporating tubes
238 (as shown by the flow direction arrows) and also flows into
pool boiling tubes 242. The resource exits evaporating tubes 238
through resource outlet 256 and pool boiling tubes 242 through
resource outlet 258.
[0030] Subcooled liquid enters evaporator 216 through inlet 230.
Distribution system 233 uses spray nozzles 235 attached to spray
manifold 234 to spray subcooled fluid at high pressure over
evaporating tubes 238. The heat from the resource flowing through
evaporating tubes 238 allows the fluid to begin evaporating. The
fluid falls down subsequent rows of evaporating tubes 238. The
fluid falling off the last row of evaporating tubes 238 collects
and forms pool 240 at the bottom of evaporator 216. The heat from
the resource flowing through pool boiling tubes 242 causes the
fluid in pool 240 to evaporate. Therefore, the saturated vapor in
evaporator 216 consists of fluid evaporated by evaporating tubes
238 and pool boiling tubes 242. The saturated vapor travels up
through evaporator 216 and exits evaporator 216 through outlet
232.
[0031] FIG. 5 is a flow schematic including another alternate
embodiment of the present invention, system 300, including
condenser 312, pump 314, evaporator 316, turbine 318, generator
320, and recirculation pump 360. Condenser 312 includes inlet 322
and outlet 324. Pump 314 includes inlet 326 and outlet 328.
Evaporator 316 consists of a shell through which superheating tubes
336 and evaporating tubes 338 pass in tube bundles. Evaporator 316
also includes inlet 330, outlet 332, distribution system 333 with
spray manifold 334 and spray nozzles 335, vapor lanes 337, pool
340, and outlet 366. Recirculation pump 360 includes inlet 362 and
outlet 364. Turbine 318 includes inlet 344 and outlet 348. Drive
shaft 346 connects turbine 318 to generator 320.
[0032] System 300 may be an ORC system. System 100 processes a
fluid to produce power. The fluid may be a wet working fluid, which
requires superheat. The fluid enters evaporator 316 through inlet
330 using pump 314. Distribution system 333 uses spray nozzles 335
attached to spray manifold 334 to spray subcooled fluid at high
pressure over evaporating tubes 338. Distribution system 333 is
arranged in an overlaying relationship with the upper most level of
the top of evaporating tubes 338. Evaporating tubes 338 consist of
tube bundles which are positioned in a staggered manner under
distribution system 333 to maximize contact with the fluid sprayed
out of distribution system 333 onto the upper portion of
evaporating tubes 338. To begin the evaporation process, the first
row of evaporating tubes 338 is sprayed with subcooled fluid.
Distribution system 333 is designed such that the first row of
evaporating tubes 338 is drenched and covered but not oversupplied
with fluid, starting the evaporation process. The fluid falls down
subsequent rows of evaporating tubes 338. The fluid falling off the
last row of evaporating tubes 338 collects and forms pool 340 at
the bottom of evaporator 316. A control system may be employed to
ensure that no dry-out occurs along the length and width of
evaporating tubes 338.
[0033] In one embodiment, the fluid spray from spray manifold 334
is controlled such that 15% of the fluid sprayed falls off the last
row of evaporating tubes 338, and the rest of the fluid sprayed is
evaporated by evaporating tubes 338. In an alternative embodiment,
spray manifold 334 is controlled such that 20% of the fluid sprayed
falls off the last row of evaporating tubes 338. In another
alternative embodiment spray manifold 334 is controlled such that
25% of the fluid sprayed falls off the last row of evaporating
tubes 338. In other embodiments, a control system is employed to
vary the percentage of fluid falling off of the law row of
evaporating tubes 338 between 5% and 50%.
[0034] Recirculation pump 360 is an alternative to pool boiling
tubes for evaporating pool 340. Recirculation pump 360 recirculates
the fluid from pool 340 into inlet 330 of evaporator 316. The fluid
in pool 340 exits evaporator 316 through outlet 364 and enters
recirculation pump 360 through inlet 362. The fluid from pool 340
leaves recirculation pump 360 through outlet 364, merges with the
fluid pumped from pump 314, and re-enters evaporator 316 through
inlet 330. A control system may be employed to control the flow
from recirculation pump 360 and the fluid flow from pump 314 in
order to optimize distribution of liquid and minimize the amount of
liquid pooling in pool 340.
[0035] The saturated vapor in evaporator 316 consists of fluid
evaporated by evaporating tubes 338. Superheating tubes 336 are
located above spray manifold 334. The saturated vapor travels along
the periphery of evaporator 316 in vapor lanes 337, and when the
saturated vapor reaches superheating tubes 336, superheating tubes
336 increase the temperature of the saturated vapor at a constant
pressure, which results in favorable system performance. Since the
fluid in system 300 may be a wet working fluid, superheating tubes
336 provide superheating to prevent liquid droplets from forming
when the fluid expands through turbine 318. Superheating tubes 336
therefore ensure that the saturated vapor is heated sufficiently to
result in favorable and proper performance of turbine 318.
[0036] Once the saturated vapor is superheated by superheating
tubes 336, superheated vapor exits evaporator 316 through outlet
332 and superheated vapor enters turbine 318 through inlet 344.
Turbine 18 expands superheated vapor spinning drive shaft 46, which
drives generator 20 to produce power. Turbine 318 may be
screw-shaped, axial, radial, or any other type of positive
displacement shape. Low pressure and low temperature vapor from
turbine 318 flows out through outlet 338 and into condenser 312
through inlet 322. In condenser 312, a cooler medium like air or
water flowing through condenser 312 condensers the vapor into
subcooled liquid. Subcooled liquid from condenser 312 exits through
outlet 324 and enters pump 314 through inlet 326. Pump 314 pumps
subcooled liquid through outlet 328 and into inlet 330 of
evaporator 316. The cycle is subsequently repeated to continue to
produce power.
[0037] FIG. 6 is a cross section of an alternative embodiment
evaporator, evaporator 416, of system 300 along line 6-6 in FIG. 5,
along with recirculation pump 460. Evaporator 416 consists of a
shell through which evaporating tubes 438 pass in tube bundles.
Evaporator 416 also includes inlet 430, outlet 432, distribution
system 433 with spray manifold 434 and spray nozzles 435, pool 440,
resource inlet 452, resource outlet 456, and outlet 466.
Recirculation pump 460 includes inlet 462 and outlet 464. The fluid
processed with evaporator 416 may be a dry working fluid, which
does not require superheat. Therefore, evaporator 416 does not
include superheating tubes.
[0038] During operation of evaporator 416, a resource, such as hot
water, flows into evaporating tubes 438 through resource inlet 452.
The resource continues to flow through additional evaporating tubes
438 (as shown by the flow direction arrows). The resource exits
evaporating tubes 438 through resource outlet 456. Subcooled liquid
enters evaporator 416 through inlet 430. Distribution system 433
uses spray nozzles 435 attached to spray manifold 434 to spray
subcooled fluid at high pressure over evaporating tubes 438. The
heat from the resource flowing through evaporating tubes 438 allows
the fluid to begin evaporating. The fluid falls down subsequent
rows of evaporating tubes 438. The fluid falling off the last row
of evaporating tubes 438 collects and forms pool 440 at the bottom
of evaporator 416.
[0039] Recirculation pump 460 is an alternative to pool boiling
tubes for evaporating pool 440. Recirculation pump 460 recirculates
the fluid from pool 440 into inlet 430 of evaporator 416. The fluid
in pool 440 exits evaporator 416 through outlet 464 and enters
recirculation pump 460 through inlet 462. The fluid from pool 440
leaves recirculation pump 460 through outlet 464, and re-enters
evaporator 416 through inlet 430. A control system may be employed
to control the flow of fluid into evaporator through inlet 430 in
order to optimize distribution of liquid and minimize the amount of
liquid pooling in pool 340. The saturated vapor in evaporator 416
consists of fluid evaporated by evaporating tubes 438. The
saturated vapor travels up through evaporator 416 and exits
evaporator 416 through outlet 432.
Discussion of Possible Embodiments
[0040] A system according to an exemplary embodiment of this
disclosure, among other possible things includes: a condenser with
an inlet and an outlet, a pump with an outlet and with an inlet
connected to the outlet of the condenser, and an evaporator. The
evaporator includes an inlet connected to the outlet of the pump,
an outlet, evaporating tubes, and a fluid distribution system for
spraying a fluid over the evaporating tubes. The system further
includes a turbine with an inlet connected to the outlet of the
evaporator, an outlet connected to the inlet of the condenser, and
a drive shaft. A generator is connected to the drive shaft of the
turbine.
[0041] A further embodiment of the foregoing system, wherein the
system is a power generation system.
[0042] A further embodiment of any of the foregoing systems,
wherein the fluid is a refrigerant.
[0043] A further embodiment of any of the foregoing systems,
wherein the refrigerant is a hydrofluorocarbon, hydrocarbon,
fluorinated ketone, fluorinated ether, chloro-olefin, bromo-fluoro
olefin, hydrofluoroolefin, hydrofluoroolefin ether,
hydrochlorofluoroolefin ether, linear siloxane, or cyclic
siloxane.
[0044] A further embodiment of any of the foregoing systems,
wherein the refrigerant is propane, cyclopropane, isobutene,
isobutane, n-butane, propylene, n-pentane, isopentane,
cyclopentane, R-134a, R-30, R-32, R-123, R-125, R-143a, R-134,
R-152a, R-161, R-1216, R-227ea, R-245fa, R-245cb, R-236ea, R-236fa,
R-365mfc, HT-55, R-43-10mee, HFE-7100, Novec-649, CF3I, R-1234ye,
R-1234yf, R-1234ze, R-1233zd(E), R-1233zd(Z), R-1225ye(Z),
R-1225ye(E), C5F9Cl, C5H2F10, R-1243zf, E-134a, E134, E125, E143a,
siloxane MM, dimethylether, or CO2.
[0045] A further embodiment of any of the foregoing systems,
wherein the evaporator further comprises pool boiling tubes.
[0046] A further embodiment of any of the foregoing systems,
wherein the evaporator further includes superheating tubes near the
outlet of the evaporator for heating the fluid evaporated by the
evaporating tubes and pool boiling tubes.
[0047] A further embodiment of any of the foregoing systems,
wherein the superheating tubes are next to the plurality of
evaporating tubes below the fluid distribution system.
[0048] A further embodiment of any of the foregoing systems,
wherein the superheating tubes are above the fluid distribution
system.
[0049] A further embodiment of any of the foregoing systems, and
further comprising a recirculation pump for recirculating fluid
from the evaporator to the inlet of the evaporator.
[0050] A further embodiment of any of the foregoing systems,
wherein the evaporator further includes superheating tubes near the
outlet of the evaporator for heating the fluid evaporated by the
evaporating tubes and pool boiling tubes.
[0051] A further embodiment of any of the foregoing systems,
wherein the superheating tubes are next to the plurality of
evaporating tubes below the fluid distribution system.
[0052] A further embodiment of any of the foregoing systems,
wherein the superheating tubes are above the fluid distribution
system.
[0053] A method of processing a fluid in a system according to an
exemplary embodiment of this disclosure; the method, among other
possible things includes: condensing the fluid in a condenser,
pumping the fluid from the condenser into an evaporator, and
spraying the fluid from a fluid distribution system in the
evaporator to cover evaporating tubes in the evaporator. The method
further includes dripping an excess of the fluid off of the
evaporating tubes to form a pool in the evaporator, evaporating the
fluid from the evaporating tubes, expanding the evaporated fluid in
a turbine, and producing power in a generator using the fluid
expanded in the turbine.
[0054] A further embodiment of the foregoing method, wherein the
refrigerant is a hydrofluorocarbon, hydrocarbon, fluorinated
ketone, fluorinated ether, chloro-olefin, bromo-fluoro olefin,
hydrofluoroolefin, hydrofluoroolefin ether, hydrochlorofluoroolefin
ether, linear siloxane, or cyclic siloxane.
[0055] A further embodiment of any of the foregoing methods,
wherein the refrigerant is propane, cyclopropane, isobutene,
isobutane, n-butane, propylene, n-pentane, isopentane,
cyclopentane, R-134a, R-30, R-32, R-123, R-125, R-143a, R-134,
R-152a, R-161, R-1216, R-227ea, R-245fa, R-245cb, R-236ea, R-236fa,
R-365mfc, HT-55, R-43-10mee, HFE-7100, Novec-649, CF3I, R-1234ye,
R-1234yf, R-1234ze, R-1233zd(E), R-1233zd(Z), R-1225ye(Z),
R-1225ye(E), C5F9Cl, C5H2F10, R-1243zf, E-134a, E134, E125, E143a,
siloxane MM, dimethylether, or CO2.
[0056] A further embodiment of any of the foregoing methods,
wherein evaporating the fluid further comprises evaporating the
fluid from the pool with pool boiling tubes.
[0057] A further embodiment of any of the foregoing methods, and
further comprising heating the evaporated fluid with superheating
tubes prior to expanding the evaporated fluid in the turbine.
[0058] A further embodiment of any of the foregoing methods, and
further comprising recirculating the fluid from the pool in the
evaporator back to the fluid distribution system of the
evaporator.
[0059] A further embodiment of any of the foregoing methods, and
further comprising heating the evaporated fluid with superheating
tubes prior to expanding the evaporated fluid in the turbine.
[0060] A further embodiment of any of the foregoing methods,
wherein the excess of the fluid dripping off of the evaporating
tubes comprises between 15 and 25 percents of the fluid sprayed
from the fluid distribution system.
[0061] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *