U.S. patent number 10,385,737 [Application Number 15/927,097] was granted by the patent office on 2019-08-20 for device for controlling supply of working fluid.
This patent grant is currently assigned to Doosan Heavy Industries Construction Co., Ltd. The grantee listed for this patent is DOOSAN HEAVY INDUSTRIES & CONSTRUCTION CO., LTD.. Invention is credited to Jeong Ho Hwang, Seung Gyu Kang, Hyo Seong Lee, Sang Sin Park.
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United States Patent |
10,385,737 |
Park , et al. |
August 20, 2019 |
Device for controlling supply of working fluid
Abstract
A device for controlling a supply of a working fluid to a power
generation cycle with a compressor compressing the working fluid
and a precooler cooling the working fluid supplied to the
compressor comprises a storage tank storing the working fluid
supplied to the power generation cycle and a flotation tank
disposed between the precooler and the compressor to flow or
temporarily store the working fluid, wherein a pressure within the
flotation tank and a flow rate of the working fluid are controlled
based on pressures at an inlet of the compressor and an outlet of
the precooler.
Inventors: |
Park; Sang Sin
(Chungcheongbuk-do, KR), Kang; Seung Gyu (Yongin-si,
KR), Hwang; Jeong Ho (Yongin-si, KR), Lee;
Hyo Seong (Ulsan, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
DOOSAN HEAVY INDUSTRIES & CONSTRUCTION CO., LTD. |
Changwon-si, Gyeongsangnam-do |
N/A |
KR |
|
|
Assignee: |
Doosan Heavy Industries
Construction Co., Ltd (Gyeongsangnam-do, KR)
|
Family
ID: |
62628711 |
Appl.
No.: |
15/927,097 |
Filed: |
March 21, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180283222 A1 |
Oct 4, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 28, 2017 [KR] |
|
|
10-2017-0039383 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01K
13/006 (20130101); F22D 5/06 (20130101); F01K
3/16 (20130101); F01K 25/103 (20130101); F01K
7/165 (20130101); F22D 3/00 (20130101) |
Current International
Class: |
F01K
25/10 (20060101); F01K 13/00 (20060101); F22D
5/06 (20060101); F01K 7/16 (20060101); F22D
3/00 (20060101); F01K 3/16 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
A Japanese Office Action dated Mar. 27, 2019 in connection with
Japanese Patent Application No. 2018-057234 which corresponds to
the above-referenced U.S. application. cited by applicant.
|
Primary Examiner: Laurenzi; Mark A
Assistant Examiner: Hu; Xiaoting
Attorney, Agent or Firm: Invenstone Patent, LLC
Claims
What is claimed is:
1. A device for controlling a supply of a working fluid to a power
generation cycle with a compressor compressing the working fluid
and a precooler cooling the working fluid supplied to the
compressor, the device comprising: a storage tank storing the
working fluid supplied to the power generation cycle; a flotation
tank disposed between the precooler and the compressor to flow or
temporarily store the working fluid; a supply pump disposed between
the storage tank and the flotation tank to supply the working fluid
from the storage tank to the flotation tank; and a control valve
disposed between the storage tank and the flotation tank to
discharge the working fluid from the flotation tank to the storage
tank, wherein a pressure within the flotation tank and a flow rate
of the working fluid are controlled based on pressures at an inlet
of the compressor and an outlet of the precooler.
2. The device of claim 1, wherein the flotation tank is a piston
accumulator tank.
3. The device of claim 2, wherein the flotation tank comprises: a
tank body into which the working fluid is introduced; and a piston
installed inside the tank body to be elevated by a control fluid
supplied from the outside.
4. The device of claim 3, wherein the flotation tank further
comprises: a control fluid inflowing portion provided at a lower
end of the tank body and having the control fluid inflowing and
outflowing therethrough; a first inlet provided at one side of the
tank body and having the working fluid inflowing from the supply
pump thereinto; and a first outlet provided at the other side of
the tank body and having the working fluid discharged to the
control valve therethrough.
5. The device of claim 4, wherein the flotation tank further
comprises: a second inlet provided at an upper part of the tank
body and having the working fluid inflowing from the precooler
thereinto; and a second outlet provided at the upper part of the
tank body and having the working fluid discharged to the compressor
therethrough.
6. The device of claim 5, wherein when the pressure at the outlet
of the precooler or the pressure at the inlet of the compressor
rises, the control fluid is supplied to the control fluid inflowing
portion and the control valve is open to discharge the working
fluid within the flotation tank to the storage tank through the
first outlet.
7. The device of claim 6, wherein the supply of the control fluid
and the discharge of the working fluid to the storage tank are made
until a height of the piston reaches a height corresponding to a
set value.
8. The device of claim 5, wherein when the pressure at the outlet
of the precooler or the pressure at the inlet of the compressor
falls, the supply pump is operated to supply the working fluid into
the flotation tank through the first inlet.
9. The device of claim 8, wherein the supply of the working fluid
into the flotation tank is made until a height of the piston
reaches a height corresponding to a set value.
10. A device for controlling a supply of a working fluid to a power
generation cycle with a compressor compressing the working fluid
and a precooler cooling the working fluid supplied to the
compressor, the device comprising: a storage tank storing the
working fluid supplied to the power generation cycle; a flotation
tank disposed on a low pressure line of an inlet of the compressor
to flow or temporarily store the working fluid; a supply pump
disposed between the storage tank and the flotation tank to supply
the working fluid from the storage tank to the flotation tank; and
a control valve disposed between the storage tank and the flotation
tank to discharge the working fluid from the flotation tank to the
storage tank.
11. The device of claim 10, wherein if a pressure at an outlet of
the precooler or the inlet of the compressor rises, the working
fluid is discharged from the flotation tank to the storage tank,
and if the pressure at the outlet of the precooler or the inlet of
the compressor falls, the working fluid is supplied from the
storage tank to the flotation tank.
12. The device of claim 11, wherein the flotation tank is a piston
accumulator tank.
13. The device of claim 12, wherein the flotation tank comprises: a
tank body into which the working fluid is introduced; and a piston
installed inside the tank body to be elevated by a control fluid
supplied from the outside.
14. The device of claim 13, wherein the flotation tank further
comprises: a control fluid inflowing portion provided at a lower
end of the tank body and having the control fluid inflowing and
outflowing therethrough; a first inlet provided at one side of the
tank body and having the working fluid inflowing from the supply
pump thereinto; and a first outlet provided at the other side of
the tank body and having the working fluid discharged to the
control valve therethrough.
15. The device of claim 14, wherein the flotation tank further
comprises: a second inlet provided at an upper part of the tank
body and having the working fluid inflowing from the precooler
thereinto; and a second outlet provided at the upper part of the
tank body and having the working fluid discharged to the compressor
therethrough.
16. The device of claim 15, wherein when the pressure at the outlet
of the precooler or the pressure at the inlet of the compressor
rises, the control fluid is supplied to the control fluid inflowing
portion and the control valve is open to discharge the working
fluid within the flotation tank to the storage tank through the
first outlet.
17. The device of claim 16, wherein the supply of the control fluid
and the discharge of the working fluid to the storage tank are made
until a height of the piston reaches a height corresponding to a
set value.
18. The device of claim 15, wherein when the pressure at the outlet
of the precooler or the pressure at the inlet of the compressor
falls, the supply pump is operated to supply the working fluid into
the flotation tank through the first inlet.
19. The device of claim 18, wherein the supply of the working fluid
into the flotation tank is made until a height of the piston
reaches a height corresponding to a set value.
Description
CROSS-REFERENCE(S) TO RELATED APPLICATIONS
This application claims priority to Korean Patent Application No.
10-2017-0039383, filed on Mar. 28, 2017 the disclosure of which is
incorporated herein by reference in its entirety.
BACKGROUND OF THE DISCLOSURE
Field of the Disclosure
Exemplary embodiments of the present disclosure relate to a device
for controlling a supply of a working fluid, and more particularly,
to a device for controlling a supply of a working fluid capable of
efficiently and economically controlling a flow rate and a pressure
of the working fluid to supply the working fluid into a power
generation cycle.
Description of the Related Art
Various efforts for increasing a power output while decreasing the
emission of pollutants have been made. As one of such efforts,
research and development of a power generation system using
supercritical CO.sub.2 as a working fluid have been actively
conducted.
Because supercritical CO.sub.2 has a density similar to the liquid
state and viscosity similar to the gas state, an equipment
utilizing the property may be miniaturized and power consumption
required to compress and circulate the fluid may be minimized. At
the same time, supercritical CO.sub.2, with its critical points of
31.4.degree. C. and 72.8 atm much lower than the critical points of
water at 373.95.degree. C. and 217.7 atm, may be handled very
easily.
In addition, the power generation system using supercritical
CO.sub.2 is mostly operated as a closed cycle in which carbon
dioxide used for power generation is not emitted to outside, thus
greatly reducing the emission of pollutants.
The working fluid is supplied into the cycle for two purposes:
power generation and a turbo machine. For the purpose of power
generation, the working fluid is injected into a power generation
cycle to drive the turbo machine. For the purpose of the turbo
machine, the working fluid is for bearing lubrication and sealing
of the turbo machine.
U.S. Pat. No. 8,281,593 discloses a method for supplying a working
fluid stored in a storage tank into a cycle and a turbo machine
using a high-pressure piston pump. Further, a mass control tank is
provided for controlling a flow rate of the working fluid and
controlling a pressure at an inlet and an outlet of a compressor.
The mass control tank is also referred to as an inventory tank. In
general, the mass control tank is connected to a high pressure line
of the outlet of the compressor and a low pressure line of an inlet
of a precooler. As the pressure at the outlet of the compressor
increases, a high pressure valve may be open to send some of the
flow rate to the mass control tank, thereby reducing the pressure.
As the pressure at the inlet of the compressor decreases, the low
pressure valve may be open to send some of the flow rate of the
mass control tank to the inlet line of the compressor, thereby
increasing the pressure.
Therefore, since the mass control tank is connected to the high
pressure line of the outlet of the compressor, it is essential that
the mass control tank is made of expensive materials and components
capable of withstanding the high pressure, which leads to an
increase in cost and a decrease in economical efficiency.
SUMMARY OF THE DISCLOSURE
An object of the present disclosure is to provide a device for
controlling a supply of a working fluid capable of efficiently and
economically controlling a flow rate and a pressure of a working
fluid to supply the working fluid into a power generation
cycle.
Other objects and advantages of the present disclosure can be
understood by the following description, and become apparent with
reference to the embodiments of the present disclosure. Also, it is
obvious to those skilled in the art to which the present disclosure
pertains that the objects and advantages of the present disclosure
can be realized by the means as claimed and combinations
thereof.
In accordance with one aspect of the present disclosure, a device
for controlling a supply of a working fluid for supplying the
working fluid to a power generation cycle comprising a compressor
compressing the working fluid and a precooler cooling the working
fluid supplied to the compressor comprises: a storage tank storing
the working fluid supplied to the power generation cycle; and a
flotation tank disposed between the precooler and the compressor to
flow or temporarily store the working fluid, wherein a pressure
within the flotation tank and a flow rate of the working fluid are
controlled depending on pressures at an inlet of the compressor and
an outlet of the precooler.
The device may further comprise: a supply pump disposed between the
storage tank and the flotation tank to supply the working fluid
from the storage tank to the flotation tank; and a control valve
disposed between the storage tank and the flotation tank to
discharge the working fluid from the flotation tank to the storage
tank.
The flotation tank may be a piston accumulator type tank.
The flotation tank may comprise: a tank body into which the working
fluid is introduced; and a piston installed inside the tank body to
be elevated by a control fluid supplied from the outside.
The flotation tank may further comprise: a control fluid inflowing
portion provided at a lower end of the tank body and having the
control fluid inflowing and outflowing therethrough; a first inlet
provided at one side of the tank body and having the working fluid
inflowing from the supply pump thereinto; and a first outlet
provided at the other side of the tank body and having the working
fluid discharged to the control valve therethrough.
The flotation tank may further comprise: a second inlet provided at
an upper part of the tank body and having the working fluid
inflowing from the precooler thereinto; and a second outlet
provided at the upper part of the tank body and having the working
fluid discharged to the compressor therethrough.
When P1 which is a pressure at a rear end of the precooler or P2
which is a pressure at a front end of the compressor rises, the
control fluid may be supplied to the control fluid inflowing
portion and the control valve may be open to discharge the working
fluid within the flotation tank to the storage tank through the
first outlet.
The supply of the control fluid and the discharge of the working
fluid to the storage tank may be made until a height of the piston
reaches a height corresponding to a set value.
When P1 which is a pressure at a rear end of the precooler or P2
which is a pressure at a front end of the compressor falls, the
supply pump may be operated to supply the working fluid into the
flotation tank through the first inlet.
The supply of the working fluid into the flotation tank may be made
until a height of the piston reaches a height corresponding to a
set value.
In accordance with another aspect of the present disclosure, a
device for controlling a supply of a working fluid for supplying
the working fluid to a power generation cycle comprising a
compressor compressing the working fluid and a precooler cooling
the working fluid supplied to the compressor comprises: a storage
tank storing the working fluid supplied to the power generation
cycle; a flotation tank disposed on a low pressure line of an inlet
of the compressor to flow or temporarily store the working fluid; a
supply pump disposed between the storage tank and the flotation
tank to supply the working fluid from the storage tank to the
flotation tank; and a control valve disposed between the storage
tank and the flotation tank to discharge the working fluid from the
flotation tank to the storage tank.
If a pressure at an outlet of the precooler or an inlet of the
compressor rises, the working fluid is discharged from the
flotation tank to the storage tank, and if the pressure at the
outlet of the precooler or the inlet of the compressor falls, the
working fluid may be supplied from the storage tank to the
flotation tank.
The flotation tank may be a piston accumulator type tank.
The flotation tank may comprise: a tank body into which the working
fluid is introduced; and a piston installed inside the tank body to
be elevated by a control fluid supplied from the outside.
The flotation tank may further comprise: a control fluid inflowing
portion provided at a lower end of the tank body and having the
control fluid inflowing and outflowing therethrough; a first inlet
provided at one side of the tank body and having the working fluid
inflowing from the supply pump thereinto; and a first outlet
provided at the other side of the tank body and having the working
fluid discharged to the control valve therethrough.
The flotation tank may further comprise: a second inlet provided at
an upper part of the tank body and having the working fluid
inflowing from the precooler thereinto; and a second outlet
provided at the upper part of the tank body and having the working
fluid discharged to the compressor therethrough.
When P1 which is a pressure at a rear end of the precooler or P2
which is a pressure at a front end of the compressor rises, the
control fluid may be supplied to the control fluid inflowing
portion and the control valve may be open to discharge the working
fluid within the flotation tank to the storage tank through the
first outlet.
The supply of the control fluid and the discharge of the working
fluid to the storage tank may be made until a height of the piston
reaches a height corresponding to a set value.
When P1 which is a pressure at a rear end of the precooler or P2
which is a pressure at a front end of the compressor falls, the
supply pump may be operated to supply the working fluid into the
flotation tank through the first inlet.
The supply of the working fluid into the flotation tank may be made
until a height of the piston reaches a height corresponding to a
set value.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and other advantages of the
present disclosure will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
FIG. 1 is a schematic diagram showing an example of a power
generation cycle to which a device for controlling a supply of a
working fluid according to an embodiment of the present disclosure
is applied;
FIG. 2 is a schematic diagram showing an example of the device for
controlling the supply of the working fluid shown in FIG. 1;
and
FIGS. 3 and 4 are schematic diagrams showing an operating state of
the device for controlling the supply of the working fluid shown in
FIG. 2.
DESCRIPTION OF SPECIFIC EMBODIMENTS
Hereinafter, a device for controlling a supply of a working fluid
according to an exemplary embodiment of the present disclosure will
be described in detail with reference to the accompanying
drawings.
Generally, the power generation system using supercritical CO.sub.2
configures a close cycle in which CO.sub.2 used for power
generation is not emitted to outside, but uses supercritical
CO.sub.2 as a working fluid.
The power generation system using supercritical CO.sub.2 can use
exhaust gas emitted from a thermal power plant or the like since a
working fluid is the supercritical CO.sub.2. Accordingly, the power
generation system using supercritical CO.sub.2 may not only be used
as a single power generation system, but also be used for a hybrid
power generation system with the thermal power generation system.
The working fluid of the power generation system using
supercritical CO.sub.2 may also supply CO.sub.2 separated from the
exhaust gas and may also supply CO.sub.2 separately.
Supercritical CO.sub.2 (hereinafter, referred to as working fluid)
within the cycle passes through a compressor, and it is then heated
while passing through a heat source such as a heater to become a
high-temperature high-pressure working fluid, thereby driving a
turbine. A generator or a pump is connected to the turbine, the
turbine connected to the generator produces power, and the turbine
connected to the pump operates the pump. The working fluid passing
through the turbine is cooled while passing through a heat
exchanger, and the cooled working fluid is again supplied to the
compressor to be circulated within the cycle. The turbine or the
heat exchanger may be provided in multiple.
The power generation system using supercritical CO.sub.2 according
to various embodiments of the present disclosure includes a system
where all the working fluids flowing within the cycle are in the
supercritical state as well as a system where most of the working
fluids are in the supercritical state and the rest of the working
fluids are in a subcritical state.
Further, in various embodiments of the present disclosure, CO.sub.2
is used as the working fluid. Here, CO.sub.2 may include pure
carbon dioxide, carbon dioxide including slight impurities, and
even a fluid where carbon dioxide is mixed with one or more fluids
as additives.
FIG. 1 is a schematic diagram showing an example of a power
generation cycle to which a device for controlling a supply of a
working fluid according to an embodiment of the present disclosure
is applied.
As shown in FIG. 1, the power generation cycle may be a power
generation cycle using supercritical CO.sub.2, which comprises one
turbine, a plurality of recuperators 200, and a plurality of
external heat exchangers 300.
The components of the present disclosure are connected to each
other by a transfer pipe in which the working fluid flows. However,
when a plurality of components is integrated, the components and
areas actually serving as the transfer pipe may be present in the
integrated components. Therefore, even in this case, it is to be
understood that the working fluid flows along the transfer pipe,
where in the present disclosure, the transfer pipe is indicated by
numbers in parentheses.
The working fluid supplied into the cycle through the device for
controlling the supply of the working fluid is compressed to a high
pressure by a compressor 100. Some of the working fluid is branched
to the recuperator 200, and a part thereof is branched to the
external heat exchanger 300.
The recuperator 200 is configured to comprise a first recuperator
210 and a second recuperator 230 which are arranged in series, such
that the working fluid passing through the first recuperator 210 is
sequentially introduced into the second recuperator 230. The
working fluid passing through the turbine 400 is first introduced
into the first recuperator 210, such that the first recuperator 210
exchanges heat with a relatively higher-temperature working fluid
than the second recuperator 230.
The external heat exchanger 300 is configured to comprise a first
heat exchanger 310 and a second heat exchanger 330. The first heat
exchanger 310 and the second heat exchanger 330 use a gas
(hereinafter, a waste heat gas) having waste heat like exhaust gas
emitted from a boiler of a power plant as a heat source, and serve
to exchange heat between the waste heat gas and a working fluid
circulating within a cycle to heat the working fluid.
When the plurality of heat exchangers 300 are provided, they may be
classified into relatively low temperature, medium temperature,
high temperature or the like depending on the temperature of the
waste heat gas. That is, the heat exchanger can perform heat
exchange at the high temperature as the waste heat gas is
introduced into an inlet end, and the heat exchanger performs heat
exchange at the lower temperature as the waste heat gas is
discharged through an outlet end.
In the present embodiment, the first heat exchanger 310 may be a
heat exchanger using relatively a high or medium-temperature waste
heat gas compared to the second heat exchanger 330, and the second
heat exchanger 330 may be a heat exchanger using a relatively
medium or low-temperature waste heat gas. That is, an example in
which the first heat exchanger 310 and the second heat exchanger
330 are sequentially disposed from the inlet end into which the
waste heat gas is introduced toward the outlet end will be
described.
As described above, some of the working fluid passing through the
compressor 100 is sent to the second recuperator 230 and exchanges
heat with the working fluid passing through the first recuperator
210 to be heated primarily, and is then sent to the first
recuperator 210 and exchanges heat with the working fluid passing
through the turbine 400 to be heated. Thereafter, the working fluid
is transferred to a front end of the first heat exchanger 310.
Some of the working fluid passing through the compressor 100 is
sent to the second heat exchanger 330 and exchanges heat with the
waste heat gas to be heated primarily, and is then mixed with the
working fluid heated by the first recuperator 210 and is supplied
to the first heat exchanger 310. The working fluid heated by the
first heat exchanger 310 is supplied to the turbine 400.
The turbine 400 is driven by the working fluid, and the turbine 400
may be connected to a generator (not shown) to produce power. The
working fluid is expanded while passing through the turbine 400,
and therefore the turbine 400 also serves as an expander. The
working fluid passing through the turbine 400 is transferred to the
first recuperator 210.
The working fluid cooled by exchanging heat with the working fluid
passing through the compressor 100 in the first recuperator 210 and
the second recuperator 230 is transferred to a precooler 50.
The precooler 50 uses air or cooling water as a refrigerant and
secondarily cools the working fluid which passes through the
recuperator 200 and is primarily cooled. The working fluid cooled
by passing through the precooler 50 is supplied to the compressor
100 via a flotation tank 500.
The device for controlling the supply of the working fluid to the
compressor 100 comprises the flotation tank 500 disposed between
the above-mentioned precooler 50 and the compressor 100, a storage
tank 10 storing the working fluid, a supply pump 20 supplying the
working fluid from the storage tank 10 to the flotation tank 500,
and a control valve 30 discharging the working fluid of the
flotation tank 500 to the storage tank 10.
The storage tank 10 which is a large-capacity reservoir capable of
storing and supplying the flow rate of the working fluid which is
required over the whole cycle has a size enough to store the amount
of working fluid required at the time of the initial driving of the
cycle. Since the storage tank 10 is also used to discharge some of
the flow rate of the working fluid within the cycle, it is
preferable to store a flow rate larger than that of the total of
working fluid within the cycle. The pressure of the working fluid
supplied from the storage tank 10 to the flotation tank 500 may be
primarily boosted by the supply pump 20 and secondarily controlled
within the flotation tank 500 to supply the working fluid to the
compressor 100.
The flotation tank 500 is installed at the inlet end of the
compressor 100, and therefore serves as a buffer against the change
in the pressure at the inlet of the compressor 100. Therefore, the
control of the pressure at the inlet of the compressor 100 may be
automatically controlled by the flotation tank 500.
The buffer action against the change in the pressure at the inlet
of the compressor 100 is made by the buffer action against the
change in the pressure within the flotation tank 500. To this end,
the flotation tank 500 is preferably provided as piston accumulator
type tank. The maximum allowable flow rate of the flotation tank
500 may be, for example, 215 L/sec. The piston accumulator type
tank has the advantage that a response speed and a reaction time of
the control reaction are very fast.
Since the flotation tank 500 is installed at the inlet end of the
compressor 100, the working fluid is temporarily stored or flows
before it gets compressed. Accordingly, since the flotation tank
500 is positioned in the low-pressure line within the cycle, the
flotation tank 500 has an advantage in that the cycle can be
economically configured without expensive materials and components
to withstand the high pressure like the conventional inventory
tank.
While the storage tank 10 should have a minimum size enough to
store the flow rate of the working fluid which is required over the
whole cycle, the flotation tank 500 is of a size enough to store
the working fluid corresponding to about 1/3 of the flow rate of
the whole cycle for the pressure buffer function. Accordingly,
since the size of the flotation tank 500 may be reduced to 1/3 of
that of the conventional inventory tank, the construction cost for
the cycle may be reduced.
The pressure buffer function of the flotation tank 500 will be
described in detail as follows.
FIG. 2 is a schematic diagram showing an example of the device for
controlling the supply of the working fluid shown in FIG. 1, and
FIGS. 3 and 4 are schematic diagrams showing an operating state of
the device for controlling the supply of the working fluid shown in
FIG. 2.
As shown in FIG. 2, the flotation tank 500 comprises a tank body
510, a piston 530 installed inside the tank body 510, a control
fluid inflowing portion 510a formed at a lower end of the tank body
510 to elevate the piston 530 and having a fluid for controlling a
position of the piston inflowing and outflowing therethrough, a
first inlet 512 provided at one side of the tank body 510 and
having the working fluid inflowing from the supply pump 20
thereinto, and a first outlet 514 provided at the other side of the
tank body 510 and having the working fluid discharged to the
control valve 30 therethrough. In addition, an upper part of the
tank body 510 spaced apart from the first inlet 512 and the first
outlet 514 is provided with a second inlet 516 into which the
working fluid is introduced from the precooler 50 and a second
outlet 518 spaced apart from the second inlet 516 and having the
working fluid discharged to the compressor 100 therethrough.
In FIG. 2, P1 is a pressure at a rear end of the precooler 50, P2
is a pressure at a front end of the compressor 100, and Ps is a
pressure inside the flotation tank 500. Further, F1 means the flow
rate of the control fluid for controlling the position of the
piston 530, where other working fluids which are fluids different
from the working fluid supplied into the cycle or fluids other than
supercritical CO.sub.2 may be used as the control fluid. Hs means a
height of the piston 530 depending on a set point in the flotation
tank 500, and H.sub.A means the height of the piston 530 depending
on the change in the pressure in the flotation tank 500. Ps and Hs
are set to a predetermined set value at the time of designing the
cycle and are controlled so that these set values in the flotation
tank 500 are maintained depending on the change in the pressure.
The method for controlling the flotation tank 500 based on the
change in the pressure will be described in detail with reference
to the above description.
As illustrated in FIG. 3, P1 may rise.
If P1 rises, the height of the piston 530 within the flotation tank
500 falls from Hs to H.sub.A. At this time, the piston 530 rises to
the set height Hs in the flotation tank 500, and at the same time
the flow rate of the control fluid is injected into F1 to maintain
the reference pressure Ps. At the same time, the control valve 30
is open to discharge the flow rate of some of the working fluid in
the flotation tank 500 and to send the working fluid to the storage
tank 10. According to this process, when Ps and Hs are maintained
at the set value, the control valve 30 is closed to stop the
injection of the flow rate of the control fluid into F1 and to stop
the discharge of the working fluid from the flotation tank 500
simultaneously. At this time, the supply pump 20 is not driven.
On the other hand, even if P2 rises, the piston 530 may fall to the
height of H.sub.A as shown in FIG. 3. Even in this case, the height
of the piston 530 falls from Hs to H.sub.A within the flotation
tank 500. Therefore, the control fluid is injected into F1 to keep
the reference pressure Ps, and the control valve 30 is open to
raise the piston 530 to Hs, thereby discharging some of the working
fluid within the flotation tank 500 to the storage tank 10. When Ps
and Hs are maintained at the set value, the control valve 30 is
closed to stop the injection of the flow rate of the control fluid
into F1 and to stop the discharge of the working fluid from the
flotation tank 500 simultaneously.
Conversely, as illustrated in FIG. 4, P1 may fall.
If P1 falls, the height of the piston 530 within the flotation tank
500 is increased from Hs to H.sub.A. At this time, the piston 530
falls to the set height Hs within the flotation tank 500, and at
the same time the supply pump 20 is operated to maintain the
reference pressure Ps, thereby supplementing the flow rate of the
working fluid into the flotation tank 500. According to this
process, if Ps and Hs reach the set values, the supply pump 20
stops the supply of the working fluid to the flotation tank 500,
thereby maintaining Ps and Hs. At this time, the control valve 30
is not driven, and the control fluid for positioning the piston 530
is also not supplied.
In addition, even when P2 falls, the piston 530 may rise to the
height of H.sub.A as shown in FIG. 4. Therefore, the piston 530
falls to the set height Hs within the flotation tank 500, and at
the same time the supply pump 20 is operated to maintain the
reference pressure Ps, thereby supplementing the flow rate of the
working fluid into the flotation tank 500. According to this
process, if Ps and Hs reach the set values, the supply pump 20
stops to stop the supply of the working fluid to the flotation tank
500, thereby maintaining Ps and Hs.
As described above, since the pressure within the flotation tank
and the flow rate of the working fluid are changed depending on the
change in the pressure at the inlet of the compressor and the
outlet of the precooler, the pressure within the flotation tank and
the height of the piston may be maintained at a predetermined set
value. As described above, since the flotation tank serves as the
buffer depending on the change in the pressure at the inlet of the
compressor, the flotation tank does not require the separate
pressure control and therefore needs not use the expensive
materials and components like the conventional inventory tank, such
that the construction cost of the cycle may be saved. Further, the
flow rate of the working fluid may be efficiently controlled by
only the flotation tank, and the pressure at the inlet and outlet
of the compressor may be controlled, such that the construction
cost of the cycle can be reduced and the economical efficiency can
be improved.
According to an embodiment of the present disclosure, the device
for controlling the supply of the working fluid can control the
pressure at the inlet and outlet of the compressor without using
the expensive inventory tank and can efficiently control the flow
rate of the working fluid to save the cost of the cycle
construction, thereby improving the economical efficiency.
The various exemplary embodiments of the present disclosure, which
is described as above and shown in the drawings, should not be
interpreted as limiting the technical spirit of the present
disclosure. The scope of the present disclosure is limited only by
matters set forth in the claims and those skilled in the art can
modify and change the technical subjects of the present disclosure
in various forms. Therefore, as long as these improvements and
changes are apparent to those skilled in the art, they are
comprised in the protective scope of the present disclosure.
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