NZ620693B2 - Power plant - Google Patents
Power plant Download PDFInfo
- Publication number
- NZ620693B2 NZ620693B2 NZ620693A NZ62069312A NZ620693B2 NZ 620693 B2 NZ620693 B2 NZ 620693B2 NZ 620693 A NZ620693 A NZ 620693A NZ 62069312 A NZ62069312 A NZ 62069312A NZ 620693 B2 NZ620693 B2 NZ 620693B2
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- NZ
- New Zealand
- Prior art keywords
- medium
- gas
- air
- chamber
- valve
- Prior art date
Links
- 239000007788 liquid Substances 0.000 claims description 52
- 238000009835 boiling Methods 0.000 claims description 13
- 239000007921 spray Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 238000001514 detection method Methods 0.000 abstract description 11
- 238000010248 power generation Methods 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 68
- OFBQJSOFQDEBGM-UHFFFAOYSA-N pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 30
- 238000001816 cooling Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 9
- 238000002485 combustion reaction Methods 0.000 description 7
- 239000003054 catalyst Substances 0.000 description 6
- 238000007906 compression Methods 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000012530 fluid Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 239000006200 vaporizer Substances 0.000 description 3
- 210000001503 Joints Anatomy 0.000 description 2
- 229940035295 Ting Drugs 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000000717 retained Effects 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 238000009834 vaporization Methods 0.000 description 2
- MSSNHSVIGIHOJA-UHFFFAOYSA-N Pentafluoropropane Chemical compound FC(F)CC(F)(F)F MSSNHSVIGIHOJA-UHFFFAOYSA-N 0.000 description 1
- 210000003660 Reticulum Anatomy 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K19/00—Regenerating or otherwise treating steam exhausted from steam engine plant
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K9/00—Plants characterised by condensers arranged or modified to co-operate with the engines
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K9/00—Plants characterised by condensers arranged or modified to co-operate with the engines
- F01K9/02—Arrangements or modifications of condensate or air pumps
- F01K9/023—Control thereof
Abstract
power generating device equipped with an air removing device for detecting air that has intruded into a medium flow path of the power generating device and automatically removing the intruded air. A binary power generation device is equipped with the flow path of a medium circulating through a heat exchanger, a turbine (101), a condenser (103), and a pump (104). A method for removing air that has intruded into the flow path of the medium in the binary power generation device (102) is characterized by sequentially performing: an air intrusion detection step (S1) of calculating, based on the pressure and temperature of a gas retaining portion communicatively connected to the flow path of the medium, a pressure threshold value obtained by adding the saturated vapour pressure of the medium and a margin value and of detecting, by comparing the pressure of a gas phase portion with the pressure threshold value, that air has intruded into the medium; a medium liquefaction step (S2) of producing a gas by pressurizing a mixed gas of the medium and air to reduce the amount of the medium in the mixed gas; and an exhaust step (S3) of exhausting the gas. t exchanger, a turbine (101), a condenser (103), and a pump (104). A method for removing air that has intruded into the flow path of the medium in the binary power generation device (102) is characterized by sequentially performing: an air intrusion detection step (S1) of calculating, based on the pressure and temperature of a gas retaining portion communicatively connected to the flow path of the medium, a pressure threshold value obtained by adding the saturated vapour pressure of the medium and a margin value and of detecting, by comparing the pressure of a gas phase portion with the pressure threshold value, that air has intruded into the medium; a medium liquefaction step (S2) of producing a gas by pressurizing a mixed gas of the medium and air to reduce the amount of the medium in the mixed gas; and an exhaust step (S3) of exhausting the gas.
Description
DESCRIPTION
TITLE OF INVENTION: POWER PLANT
TECHNICAL FIELD
The present invention relates to a power plant using a
medium having a lower boiling point than water as a g
medium, equipped with an air removing device which removes an
air intruding into the working medium.
BACKGROUND ART
[00021
A power plant, using a low g point medium, for
recovering heat energy from a low-temperature heat source
which has not been utilized in conventional geothermal power
generation using a steam turbine and for generating a power
has attracted special attention as an energy ry device
recently(see Patent Literature 1).
Fig. 7 shows a basic system diagram of a tional
powerplantusingEtlowboilingpointmedium. Thispowerplant
exchanges heat between a medium having a lower boiling point
than water and a heat source by a vaporizer 100 to evaporate
this medium, rotates a turbine 101 by this medium vapor, and
operates an electric generator 102 by the rotational force,
therebyobtainhxgapower. Themediumexitingfromtheturbine
is condensed by a condenser 103 and is delivered back to the
vaporizer 100 via a preheater l05 by a circulation pump 104.
Then, the above cycle is repeated.
In l, when a medium with a high vapor pressure (1 . e . ,
a low boiling point) is used, vaporization by the vaporizer
is easy but condensation by the condenser is difficult. To
the contrary, when a medium with a low vapor pressure (i.e.,
a high boiling point) is used, vaporization is difficult but
sation is easy. From this point of view, a medium which
maximizes an enthalpy ence (heat difference) between a
turbine inlet and a turbine outlet is selected as a medium to
be used. For example, n—pentane (nC5H12) is mainly used as a
natural medium used in a condition where a ature of a
geothermal heat source is from 130°C to 140°C and a temperature
of a cooling source is from 15°C to 30°C.
The cooling source of the ser is generally
circulating cooling water or an atmosphere. Therefore, the
temperature of the cooling source is largely different between
winter and summer. Thus, in a case where the condenser is
ed only based on a cooling performance required in summer,
the cooling performance of the condenser is further enhanced
when the temperature of the cooling source drops in winter.
As shown in Fig. 4, however, the vapor pressure of
n—pentane falls to 101 kPa or lower when its ature falls
to 36°C or lower. Therefore when the temperature of the outlet
of the condenser drops to 36°C or lower in winter, a medium
flow path may be the atmospheric pressure or lower. In this
case, it is likely that an air intrudes into the medium flow
path from the main body of the condenser and various joints
of a connection pipe of the condenser or a mechanically sealed
portion of the turbine shaft, for example.
Thus, as a device for removing the air intruding the
medium in a plant d to power generation, Patent
Literatures 2 to 6 described below are known.
Patent Literature 2 discloses a binary power plant using
water instead of a low boiling point , equipped with an
air extraction device for extracting an air from drain water
of a condenser.
Patent Literature 3 discloses a power system including
a power cycle circuit 10 which circulates a working fluid in
which a high boiling point medium and a low boiling point medium
are mixed through a vapor generator 1 for heating a solution
of the working fluid and generating a vapor, a steam turbine
2 which is driven by the vapor supplied by the vapor generator
1, a ser 3 for cooling the vapor released from the steam
e to condense it to the solution, and a feed pump 16 for
supplying the solution supplied from the condenser 3 to the
vapor generator 1, in that order, wherein a concentration of
the low boiling point medium of the working fluid in the
condenser 3 is determined to provide a pressure around the
atmospheric pressure as the lowest pressure which can be
generated in the condenser 3 in the power cycle circuit 10.
Patent Literature 4 discloses a plant which includes a
chamber having a piston therein provided above an upper portion
of a condenser, a valve connecting a space below the piston
in the chamber to the condenser, a g means cooling a lower
portion of the chamber by a coolant through a wall, and a
rge valve connected to the lower portion of the chamber.
Patent Literatures 5 and 6 disclose a plant including:
a tightly sealed chamber above an upper portion of a condenser,
the chamber being ed with a movable diaphragm for
dividing the inside of the chamber into an upper portion and
a lower portion; two flow rate control valves arranged between
the condenser and the lower portion of the chamber in series;
a cooling means for cooling the lower portion of the chamber
with a t through a wall; and a rge valve ted
to the lower portion of the chamber.
PRIOR ART NTS
PATENT LITERATURE (PTL)
PTL 1: JP 862—26304
PTL 2: JP 2003-120513
PTL 3: JP 2007-262909
PTL 4: U.S. Patent No. 5,119,635
PTL 5: U.S. Patent No. 5,113,927
PTL 6: U.S. Patent No. 5,487,765
SUMMARY OF INVENTION
PROBLEM(S) TO BE SOLVED BY THE INVENTION
Patent Literature 2 described above uses water as the
medium and therefore requires the heat source of 100°C or more.
Thus that it cannot use a lower—temperature
, there is a problem
heat source.
Patent Literature 3 described above has problems that
the pressure in the condenser ses in summer and the heat
generation efficiency is reduced, because the concentration
of the low boiling point medium is determined to provide a
pressure around the atmospheric re as the lowest
pressure which can be generated in the ser in winter.
Patent Literatures 4, 5, and.6 described above disclose
the plant for ng the air from the medium, but merely refer
to an example in which the plant is regularly operated every
minutes as an operation timing of the plant. Thus, there
is a problem that an outflow of the medium increases because
the air removing operation is performed more than.necessary.
In view of the above problems, it is an object of the
present invention to provide a power plant equipped with an
intruding air ng device which can detect an air intruding
into a medium flow path of the power plant t stopping
the power plant and reduce the amount of a working medium
exhausted to the outside of the plant.
MEANS TO SOLVE THE M (S)
To achieve the entioned. object, the present
invention is terized in that, in a power plant including:
a heat exchanger configured to exchange heat between.a medium
having a lower boiling point than water and a heat source to
generate a medium gas; a turbine configured to receive a
pressure of the medium gas supplied from the heat exchanger
to rotate; an electric generator configured to be connected
to the turbine; a condenser configured.to cool the medium gas
discharged from the turbine; a circulation pump configured.to
supply the medium released from the condenser to the heat
exchanger; a medium flow path configured to pass through the
heat ger, the turbine, the condenser, and the
circulation pump; and an air removing device configured to
removeenlairintrudingintothenedium,theairremovingdevice
includes: a gas retaining portion provided on an outlet side
of the condenser and configured to retain a gas in the ;
a pressure gauge configured to measure a pressure in the gas
retaining portion; a thermometer configured to measure a
temperature in the gas retaining portion; a ller
configured to calculate a pressure threshold value based on
a saturated vapor pressure value of the medium calculated using
the temperature of the thermometer, and compare a pressure
value of the re gauge and the pressure threshold value
to determine whether or not an air has intruded into the medium;
and a release means configured to release the gas in the gas
retaining portion in a case where it is determined that the
air has intruded.
The release means includes: a first chamber to which the
gas retained in the gas retaining portion is transferred in
a case where the controller determines that the air has
intruded; and a medium supply means ured to supply a
liquid medium to the first chamber so that the gas is compressed.
The gas remaining in the first chamber is released after the
medium is supplied.
The medium supply means may include a liquid medium tank
ured to store the liquid medium and a liquid medium feed
pump configured to supply the liquid medium from the liquid
medium tank to an inside of the first chamber. Also, the medium
supply means may include a valve provided in the medium flow
path on an outlet Side of the Circulation pump, a branching
pipe configured to branch from a pipe between the circulation
pump and the valve and connect to the first chamber, and another
valve provided in the branching pipe, and when ining
intrusion of the air, the controller may control the valve
provided in the medium flow path on the outlet side of the
circulation pump to be closed and the other valve provided in
the branching pipe to be opened.
The release means is characterized by including: a first
valve provided in a pipe connecting the gas ing portion
and a lower portion of. the first chamber; a second valve
provided in a pipe connecting the liquid medium feed pump and
the first chamber; a third valve provided in a pipe connecting
an upper portion of the first chamber to a second chamber,- a
fourth valve configured to release the gas from the second
chamber; and a fifth valve ed in a pipe connecting the
gas retaining portion to the upper portion of the first chamber.
The ller is terized by, when determining
that the air has intruded, controlling the second valve and
the third valve to be closed and the first valve and the fifth
valve to be opened so that the gas in the gas retaining portion
is transferred to the first chamber, and then controlling the
first valve and the fifth valve to be closed, the second valve
to be opened, and the liquid medium feed pump to supply the
liquid medium to the first chamber so that the gas is compressed,
and subsequently controlling the third valve to be opened while
the fourth valve is Closed.so that the gas in.the first chamber
is transferred.to the second.chamber, and then.controlling the
third valve to be closed and the fourth valve to be opened so
that the gas in the second chamber is released to an outside
of the second chamber.
The power plant may r include: a combustor
configured to burn the medium remaining in the gas ed
from the second chamber; and.an.air supply portion configured
to supply an.air to the combustor. Furthermore, a sixth valve
may be provided in.a.pipe connecting to the combustor and the
airsupplyportiontoeachother,andthecontrollermaycontrol
opening degrees of the fourth valve and the sixth valve to
adjust a flow rate.
The controller preferably determines that the air has
intruded when the re value of the pressure gauge is larger
than the pressure old value which is preferably
calculated by adding a margin value to the saturated vapor
pressure value. The .value is a preset fixed value or
a proportional value obtained by multiplying the saturated
vapor pressure value by a coefficient.
[00201
Furthermore, it is preferable that a spray nozzle is
provided for spraying the liquid medium into the first chamber.
As the medium used in the present invention, an organic
low boiling point medium such as s chlorofluorocarbons,
especially R245fa, and n-pentane can be used.
EFFECTS OF THE INVENTION
According to the present invention, the pressure
threshold value obtained by adding the margin value to the
saturated vapor pressure value of the medium calculated based
on the ature in a liquid phase portion of the gas
ing n and the pressure value of a gas phase portion
of the gas retaining portion are compared with each other,
y intrusion of an air is detected. Therefore, it is
possible to automatically detect the intrusion of the air into
the medium flow path of the power plant . Moreover, the amount
of the working medium released to the outside of the plant can
be reduced. Also, it is possible to t reduction in the
power generation efficiency caused by a lowered condensing
performance of the condenser because of intrusion of an air
not condensed by the condenser into the medium.
BRIEF DESCRIPTION OF DRAWINGS
[Fig. 1] Fig. l is a diagram showing the constitution of a plant
according to an example of the present invention.
[Fig. 2] Fig. 2 is a diagram schematically showing an
operational sequence of the plant according to the example of
the present invention.
[Fig. 3] Fig. 3 is a diagram illustrating the details of the
operational sequence of the plant according to the example of
the present invention.
[Fig. 4] Fig. 4 is a graph of a saturated vapor pressure of
n—pentane.
[Fig. 5] Fig. 5 is a diagram showing a volume ratio of n—pentane
ted in an air, using a pressure and a temperature as
parameters.
[Fig. 6] Fig. 6 is a diagram g volume ratios of respective
chambers of the plant according to the example of the t
invention and an associated ratio of n-pentane.
[Fig. 7] Fig. 7 is a m showing the constitution of a
conventional power plant using a general medium having a low
boiling point.
PTION OF EMBODIMENTS
Embodiments of the present invention.will be described
below based on the gs. First, description is now made
to an example of the embodiment of the present invention based
on Figs. 1 to 6.
Fig. 1 is a diagram showing the constitution of an
intruding air removing device according to an example of the
present invention. A condenser 103 in Fig. 1 corresponds to
the condenser 103 in Fig. 7. A gas retaining portion 1 is
connected to an upper n of an outlet—side collector of
the ser 103 . An air intruding into a medium is collected
into the gas retaining portion 1 via the outlet-side tor.
To the gas retaining portion 1, a thermometer 10 for measuring
the temperature in the gas retaining portion 1 and a pressure
gauge 11 for measuring the pressure in the gas retaining portion
1 are provided.
A first chamber 2 is ted to the gas retaining
portion 1 with a pipe via a valve 12. Moreover, a pipe is
provided for ting an upper portion of. the first chamber
2 and the gas retaining portion 1 to each other. This pipe
is ed with a valve 16 . To the first chamber 2 a pressure
gauge 7, a liquid level gauge (higher level) 8, and a liquid
level gauge (lower level) 9 are provided in that order from
the upper portion of the chamber.
A liquid medium feed pump 18 is connected to the inside
of the first chamber 2 with a pipe via a flowmeter 6 for liquid
pentane and a valve 13. At the outlet for the liquid pentane
of this pipe, a spray nozzle 25 is provided.
A second chamber 3 is connected to an upper portion of
the first chamber 2 with a pipe via a valve 14.
A combustor 4 is provided with combustion catalyst
therein, and a lower portion of the combustor 4 is ted
to the second chamber 3 with a pipe via a valve 15. An air
supply means 19 is connected to the combustor 4 with a pipe
via a valve 17. e supplied from the second chamber 3
is mixed with an air supplied from the air supply means 19,
and is burned by the combustion catalyst in the combustor 4
to produce an exhaust gas. The produced exhaust gas is
ed to the atmosphere. In the combustor 4, for making
the combustion catalyst work, a heater 4a is provided which
controls the combustion catalyst to a predetermined
temperature. The combustor 4, the air supply portion 19, the
valve 17 and the pipes connecting those are not essential
components,butareunnecessaryixuacasewherethegasreleased
from the valve 15 is d.by the atmosphere without being
burned.
A controller 5 is connected to the meter 10, the
pressure gauge 11, the pressure gauge 7, the liquid level gauge
(higher level) 8, the liquid level gauge (lower level) 9, and
the ter 6 with signal lines, respectively. Signals from
the instruments are tively input to the controller 5.
Moreover, the controller 5 is connected to the valves 12, 13,
14, 15, 16, and 17 with electric wires, respectively, to control
opening and closing of the .
Another ment of this example may be ured to
use the circulation pump 104 also as the liquid medium feed
pump 18 the condenser 103 and the
, substitute the pipe between
circulation pump 104 for a liquid medium tank 24, provide a
valve in the pipe at the outlet of the circulation pump 104,
provide a pipe branching from a portion between this valve and
the circulation pump 104 and connecting to the first chamber
2, and provide the valve 13 in this branching pipe.
Next, an operation of this plant is described. Figs.
2 and 3 are diagrams schematically showing an operational
sequence of the plant according to the first embodiment of the
t invention. The controller 5 performs an air‘ intrusion
detection step Sl, a medium liquefaction step S2 , and an exhaust
step S3 in that order. After the exhaust step S3 is finished,
the control flow loops back to the air intrusion detection step
81. The intruding air removing device may be configured to
operate at all times. More desirably, the intruding air
removing device may be operated only when it is confirmed that
the pressure of the pressure gauge 11 has fallen to the
atmospheric pressure or lower (in a case where the medium is
n-pentane the medium temperature has fallen to 36°C or lower)
after the previous operation. This is because, if a condition
where the re in the medium flow path is equal to or higher
than the atmospheric pressure ues, it is difficult for
an air to intrude into the medium flow path from the outside.
First, the air intrusion detection step 81 is described.
The controller 5 obtains the signal of the re gauge
11 provided in a gas phase portion of the gas retaining portion
1 and the signal of the thermometer 10 ed in a liquid
phase portion of the gas retaining portion 1, and calculates
a pressure threshold value obtained by adding a margin value
(margin) to a saturated vapor pressure value of the medium
calculated based on the temperature of the thermometer. If
the pressure value of the pressure gauge 11 is equal to or less
than the pressure threshold value, measurements of the
pressure value and the temperature are ued. If the
pressure value of the pressure gauge 11 is higher than the
pressure threshold value, it is determined that an air has
ed into the medium and the control flow goes to the next
step. The above—described margin value is set to a fixed value
or a proportional value which is obtained by multiplying the
aforementioned saturated vapor pressure value of the medium
calculated based on the temperature of the thermometer by a
coefficient . More specifically, the saturated vapor pressure
(Ps) at a temperature (T1) is calculated using the following
Equation 1.
PS = O . 0003 (T1) + 0 . 0159 (T1)2 + l. 1844 (T1) + 24 .316
(Equation 1)
The margin ‘value is determined. via several tests
considering the number and conditions of joints. In case of
the fixed value, for example, the margin value is set to about
% of a value at 1 atmosphere. In case of the proportional
value, the aforementioned coefficient is set to about 0.1.
Next, the medium liquefaction.step 82 is described. In
this step, an air—containing gas retained in the gas ing
portion is transferred.to the first chamber 2, and the gas is
Q} ssed by supplying a liquid medium into the first chamber
2, so that the medium in the gas is liquefied and the amount
of the medium in the gas is reduced.
More ically, after a state where the respective
valves 12, 13, 14, 15, 16, and.17 of the intruding air removing
device shown in Fig. 1 are closed, the valves 12 and 16 are
opened. to er the air—containing' gas from the gas
retaining portion 1 to the first chamber 2. If a detection
value of the liquid level gauge (lower level) 9 which es
the liquid level of the medium in the first chamber 2 is at
a predetermined lower liquid level threshold value or higher,
the state where the valves 12 and 16 are opened is continued.
When the detection value of the liquid level gauge (lower
level) 9 falls below the predetermined lower liquid level
threshold value, the valves 12 and 16 are closed to seal the
first chamber 2. Then, the valve 13 is opened and the liquid
medium is supplied from the liquid medium tank 24 to the first
chamber 2 by the liquid medium feed pump 18. During a period
in which the detection value of the liquid level gauge (higher
level) 8 is at a gmedetermined higher liquid level threshold
value or lower, the state where the valve 13 is opened is
continued.
When liquid pentane is introduced into the first chamber
2 to ss the air—containing gas, the gas temperature rises.
This rise in temperature is given by the following Equation
T2 = Tl x [P2/P1] ”“1”“ (Equation 2)
T2: Gas temperature after compression (K)
T1: Gas temperature before ssion (K)
P2: Gas pressure after compression (MPa)
P1: Gas pressure before compression (MPa)
k: Specific heat ratio
m: Stage number of compression
For example, when tic compression of an air of 30°C
saturated with pentane is carried out from 101 kPa to 1 MPa,
the temperature rise difference (AT) is 83°C. This rise in
temperature can be suppressed by injecting liquid pentane
which is made fine by the spray nozzle into the first chamber
2, instead of simply injecting liquid pentane into the first
chamber 2. A portion of n-pentane saturated in the
air—containing gas is cooled to be ied, and can be
collected. Injection using the spray can reduce the
temperature in the first r 2 more rapidly than in a method
for injecting liquid pentane without spraying it.
When the detection value of the liquid level gauge
(higher level) 8 exceeds the ermined higher liquid level
threshold value, the valve 13 is closed and the liquid medium
feed pump 18 is stopped.
Next, the exhaust step S3 is described. First, a counter
is initialized to 0. Then, the first chamber 2 and the second
chamber 3 are made to communicate with each other, so that a
portion of the gas compressed in the first chamber 2 is
transferred to the second Chamber 3. More specifically, a
state where the valve 15 is closed and the valve 14 is opened
is continued for a predetermined time. Then, the valve 14 is
closed.
Subsequently,thegasisreleasedfromthesecondchamber
3 to the outside of the plant. At this time, the combustor
4, the air supply portion 19, the valve 17 and the pipes
ting those to one another are not essential components.
For example, in a case where the gas released from the valve
is d by the atmosphere without being burned, the valve
may be opened to release the gas to the atmosphere as it
[O 04 1]
In a case where the gas is burned and is then released
to the atmosphere, it is expected that the gas cannot be
completely burned only by oxygen contained in the gas .
In case
of n—pentane, for example, when a ratio of mixing with an air
exceeds the combustion range (1.5% to 7.8%) of n~pentane,
oxygen has to be supplied. For ing the air amount to
this range, an air is uced via the valve 17. This air
is desirably supplied from compressed air supply equipment.
For example, an air for mentation for operating
instrumentation devices of the plant may be used.as this air.
More specifically, the following procedure is performed. The
combustor 4 is provided therein with a ceramic honeycomb filter
carrying platinum fine particles as combustion catalyst.
While the inside of the combustor 4 is heated to be at a
temperature from 200°C to 350°C by the heater 4a, the valves
17 and 15 are opened to supply the gas and the air to the
combustor 4, thereby the medium is burned. This state is
continued for a predetermined time. Then, the valves 15 and
17 are closed. Subsequently, the counter is incremented by
one. If the counter is less thanN times which is a predetermined
number of times, the procedure loops back, as shown in Fig.
3 . If the counter is N times which is the ermined number
of times or more, the procedure goes out of this loop. The
number N is appropriately set in ance with the volume
and pressure of the gas in the first chamber 2 after being
compressed and the volume of the second chamber 3. To burn
the gas in the combustor 4 is not essential for removing the
air intruding into the medium flow path from the medium flow
path. However, in acase of using combustible gas as the medium,
the direct release of the gas to the atmosphere can be
Q prevented.
Then, the pressure is released from the first chamber
2 to the gas ing portion 1 and the medium is moved. More
specifically, the valves 16 and 12 are opened and, after a
predetermined time has passed, the valves 16 and 12 are closed.
Then, the procedure loops back to the described air
intrusion detection step 81.
Next, the reason why ssing the mixed gas of the
air and the medium can reduce the amount of the medium in the
mixed gas is described. The amount Fst of n—pentane saturated
in an air is expressed by the following Equation 3.
Fst = Fa x (Ps/(Pc ~ Ps)) (Equation 3)
Fst: The amount of ane which is saturated in an air at
a temperature t in the standard state (Nm3)
Fa: The amount of an air in the standard state (Nm3)
PS: The saturated vapor pressure of n—pentane at the
temperature t (kPa)
Pc: The operation pressure (kPa)
The results of calculation are shown in Fig. 5, which
was done from Equation 3 made with respect to the volume ratio
of n—pentane saturated in an air using a pressure and a
temperature as parameters. It is found from Fig. 5 that the
higher the pressure is or the lower the temperature is, the
less pentane saturated in the air is. Especially, it is found
that increasing the re is extremely effective to
reduction in ane which is saturated in the air and brought
to the outside of the system.
Next, the description is made with respect to the loss
amount of n—pentane. Fig. 6 is a diagram showing the
relationship n the volume ratios of the respective
chambers of the plant according to an example of the present
ion.and.the associated ratio of pentane as an exemplary
case where the ature is kept constant at 30°C. CO
represents the volume of the gas retaining portion 1, Cl
represents the volume of the first r 2, and C2 represents
the volume of the second chamber 3. The amount of n—pentane
burned in the combustor 4 is largely varied.by a ratio of the
volume C1 of the first chamber 2 and the volume C2 of the second
chamber 3 , and is ore important in an operation
management. More specifically, the air‘ accumulated. and
compressed in the first chamber 2 is in.a pressure state where
the air is compressed and.n—pentane is saturated. Then, when
the valve 14 is opened to make the first r 2 and the second
chamber 3 communicate with each other, the pressure in the first
chamber 2 is reduced by the amount corresponding to the increase
in the volume of the second chamber 3. Because of liquid
pentane present in the first chamber 2 of n—pentane
, the amount
in the gas is increased in accordance with Equation 3 by the
amountcorresponding1x>thereductionjxlpressure. Thisshows
that the smaller the volume ratio (CZ/Cl) is, the less the
amount of n—pentane released to the e of the plant is.
The ratio of Cl/CO has almost no effect on the associated
pentane ratio.
DESCRIPTION OF THE REFERENCE NUMERALS
1: Gas retaining portion
2: First chamber
3: Second chamber
4: Combustor (filled with combustion catalyst)
4a: Heater
: Controller
6: Flowmeter for liquid pentane
7: Pressure gauge of the first chamber
8: Liquid level gauge r level) of the first chamber
9: Liquid level gauge (lower level) of the first chamber
: Thermometer of the gas retaining portion
11: Pressure gauge of the gas retaining n
12, 13, 14, 15, 16, and 17: valves
18: Liquid medium feed pump
24: Liquid medium tank
: Spray nozzle
19: Air supply portion
81: Air intrusion detection step
S2: Medium liquefaction step
S3: Exhaust step
100: zer
101: Turbine
102: Electric generator
103: Condenser
104: Circulation pump
105: Preheater
Claims (11)
- [Claim 1] A power plant comprising: a heat exchanger configured to ge heat between a medium having a lower boiling point than water and a heat source to generate a medium gas; a turbine configured to receive a pressure of the medium gas supplied from the heat exchanger to rotate; an electric generator configured to be ted.to the turbine; a condenser configured to cool the medium gas discharged from the turbine; a circulation pump configured to supply the medium discharged from the condenser to the heat exchanger; um flow path configured to pass through the heat exchanger, the turbine, the ser, and the circulation pump; and an air removing device configured to remove an air intruding into the medium, terized in that the air removing device includes: a gas retaining portion provided on an outlet side of the condenser and configured to retain a gas in the medium; a pressure gauge configured to measure a pressure in the gas retaining portion; a thermometer configured to measure a temperature in the gas retaining portion; a ller configured to calculate a pressure threshold.value based.on a saturated vapor pressure value of the medium calculated using the temperature of the thermometer, and compare a pressure value of the pressure gauge and the pressure old value to determine whether or not the air has intruded into the medium; and a releaseIneans configured.to e the gas in the gas retaining portion in a case where it is determined that the air has intruded.
- [Claim 2] A.power plant according to claim 1, wherein the release means includes a first chamber to which the gas ed in the gas retaining portion is transferred in a case where the ller determines that the air has intruded, and a medium supply means configured to supply a liquid medium to the first chamber to compress the gas, and the gas remaining in the first chamber is released after the medium is supplied.
- [Claim 3] A power plant according to claim 2, wherein the medium supplytneans includes a liquidunediun1tank:configured.to store the liquid medium and a liquid medium feed.pump configured to supply the liquid medium from the liquid medium tank to an inside of the first chamber.
- [Claim 4] A.power plant according to claim 3, wherein the release means includes a first valve provided in a pipe connecting the gas retaining portion and a lower portion of the first chamber, a second'valve provided.in21pipe connecting the liquid medium feed pump and the first chamber, a third valve provided in a pipe connecting an upper portion of the first chamber to a second chamber, a fourth valve configured to release the gas from the second r, and a fifth valve provided in a pipe connecting the gas retaining portion to the upper n of the first chamber.
- [Claim 5] A power plant according to claim 4, wherein, when determining that the air has intruded, the controller controls the second valve and the third valve to be closed and the first valve and the fifth.valve to be opened so that the gas in the gas retaining portion is transferred.to the first chamber, and then controls the first valve and the fifth valve to be closed, the second valve to be , and the liquid medium feed pump to supply the liquid medium to the first chamber so that the gas is compressed, and uently the controller controls the third valve to be opened while the fourth valve is closed so that the gas in the first chamber is transferred to the second chamber, and then ls the third valve to be closed and the fourth valve to be opened so that the gas in the second.chamber is released to an outside of the second chamber.
- [Claim 6] A power plant according to claim 4 or 5, comprising: a combustor configured to burn the medium remaining in the gas released from the second r; and an air supply portion.configured.to supply an air to the combustor.
- [Claim 7] A power plant according to claim 6, comprising a sixth valve provided in a pipe connecting to the combustor to the air supply portion, wherein the controller controls opening degrees of the fourth valve and the sixth valve to adjust a flow rate.
- [Claim 8] A power plant according to any one of claims 1 to 7, characterized.in that the controller determines that the air has intruded.when the re value of the pressure gauge is larger than the pressure threshold value.
- [Claim 9] A power plant according to any one of claims 1 to 8, n the pressure threshold value is calculated by adding a margin value to the saturated vapor re value and the margin value is a preset fixed value or a proportional value obtained by multiplying the saturated vapor pressure value by a coefficient.
- [Claim 10] A power plant according to any one of claims 2 to 7, comprising a spray nozzle configured to spray the liquid medium into the first chamber.
- [Claim 11] A power plant according to claim 2, wherein the medium supply means includes a valve provided in the medium flow path on an outlet side of the circulation pump, a branching pipe configured to branch.fron1a.pipe n the circulation pump and the valve and connect to the first chamber, and r valve provided in the branching pipe, and when detecting intrusion of the air, the controller controls the valve provided in the medium flow path on the outlet side of the circulation pump to be closed and the other valve provided in the branching pipe to be opened.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011-179444 | 2011-08-19 | ||
JP2011179444 | 2011-08-19 | ||
PCT/JP2012/070791 WO2013027643A1 (en) | 2011-08-19 | 2012-08-16 | Power generating device |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ620693A NZ620693A (en) | 2015-04-24 |
NZ620693B2 true NZ620693B2 (en) | 2015-07-28 |
Family
ID=
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