FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: OPERATION SUPPORT SYSTEM AND OPERATION SUPPORT
METHOD FOR DESULFURIZATION APPARATUS
2. Applicant(s)
NAME NATIONALITY ADDRESS
MITSUBISHI POWER, LTD. Japanese 3-1, Minatomirai 3-Chome, Nishiku,
Yokohama-shi, Kanagawa
2208401, Japan
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.
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OPERATION SUPPORT SYSTEM AND OPERATION SUPPORT METHOD FOR
DESULFURIZATION APPARATUS
TECHNICAL FIELD
[0001] This disclosure relates to an operation support system and an 5 operation support
method for a desulfurization apparatus to perform a desulfurization process on exhaust gas
using an absorbent.
BACKGROUND
10 [0002] Some plant facilities involving combustion of fuel are equipped with a
desulfurization apparatus to remove SO2 (sulfur dioxide) contained in exhaust gas. In a
desulfurization apparatus employing a wet lime-gypsum method, which is one of the methods,
SO2 contained in the exhaust gas is removed by bringing absorption liquid, in which
limestone powder is slurried in a suspended state as an absorbent, into contact with the
15 exhaust gas while circulating the absorption liquid with a circulation pump
[0003] In such a desulfurization apparatus, trial operations are performed under various
assumed operation conditions, and the operation condition under which maximum
performance can be exhibited is grasped based on date collected during the trial operations,
which is reflected in actual plant operations. Further, when evaluating the operation
20 conditions of the desulfurization apparatus, it is important to maximize an economic benefit
of a user by considering balance including utility power costs involved in the operation of the
desulfurization apparatus and sale profits to third parties of byproducts such as gypsum
generated with a desulfurization reaction and FLYASH discharged from an electric dust
collector. In particular, in recent years, from the viewpoint of environmental consideration, it
25 is necessary to consider economic factors that vary over time, such as environmental charge,
and it is desired to grasp an optimum operation condition in consideration of such factors.
[0004] For example, Patent Document 1 discloses a technique for economically operating
a desulfurization apparatus by considering, as a utility operation cost, a power cost factor
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based on the amount of limestone supplied to absorption liquid and the number of circulation
pumps to be operated for circulating the absorption liquid, and also considering an income
factor based on sales revenue of gypsum as a byproduct. Further, Patent Documents 2 and 3
disclose that the number of circulation pumps to be operated for circulating the absorption
liquid is determined so as to minimize the operation cost while the SO2 concentration 5 on the
outlet side of the desulfurization apparatus and the desulfurization ratio satisfy the required
specifications.
Citation List
10 Patent Literature
[0005]
Patent Document 1: JP2011-110441A
Patent Document 2: JP2000-015043A
Patent Document 3: JP02-180615A
15
SUMMARY
Technical Problem
[0006] In Patent Documents 1 to 3, the evaluation of the operation condition is performed
for the desulfurization apparatus in which the soundness is secured. However, in actual plant
20 facilities, desulfurization performance may be reduced due to factors such as the effects of
coexisting minor components due to fuel type changes (dissolution inhibition of limestone,
oxidation inhibition, and the like) and facility blockage. If operation is continued in such a
state, the symptoms become severe and the plant facility is forced to be stopped or the
operation load is forced to be limited, and as a result, there is a risk of causing a great
25 economic loss to the user.
[0007] It is possible to remotely monitor the operation state of a flue gas treatment facility
including a desulfurization apparatus from a place (a management facility of a plant
manufacturer or the like) geographically remote from the plant facility. However, in the
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desulfurization apparatus on site, by making an input amount of absorbent or a supply amount
of absorption liquid excessively large at the discretion of the user, sufficient desulfurization
performance is exhibited at a glance in terms of operation in the remote monitoring, and there
is a concern that the discovery of the true performance deterioration may be delayed.
[0008] At least one embodiment of the present invention has been made 5 in view of the
above circumstances, and an object thereof is to provide an operation support system and an
operation support method for a desulfurization apparatus capable of maximizing an economic
benefit of a user due to operation of a plant facility while ensuring soundness of the
desulfurization apparatus.
10
Solution to Problem
[0009] (1) To solve the abovementioned problem, an operation support system for a
desulfurization apparatus according to at least one embodiment of the present invention is an
operation support system for a desulfurization apparatus removing SO2 from exhaust gas by
15 using an absorbent, including an operation data input-acquisition unit configured to input and
acquire operation data of the desulfurization apparatus (including input values of stationary
analytic data, and hereinafter, called the operation data), an analytic performance calculation
unit configured to calculate an ideal analytic performance concerning to a desulfurization
performance of the desulfurization apparatus based on the operation data acquired by the
20 operation data input-acquisition unit, a measured performance acquisition unit configured to
acquire a measured performance when calculating the analytic performance (including not
only that acquired automatically from a distributed control system (DCS) but also that
manually input as a result of analysis, and hereinafter, called the measured performance), a
soundness evaluation unit configured to evaluate soundness of the desulfurization apparatus
25 by calculating a performance ratio of the measured performance acquired by the measured
performance acquisition unit to the analytic performance calculated by the analytic
performance calculation unit, and a support information creation unit configured to create
support information including at least one operation condition candidate set based on an
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evaluation result of the soundness evaluation unit and a balance forecast corresponding to the
operation condition candidate.
[0010] According to the configuration described above as (1), the analytic performance
concerning to the desulfurization performance is obtained by calculation based on actual
operation data of the desulfurization apparatus (which is a generic term 5 for digital data
measured by a large number of sensors incorporated in the apparatus). The analytic
performance formula for performing the calculation is composed of component formulas
related to chemical reactions such as residual concentration of the absorbent, an amount of
SO2 absorbed, a pH level, and liquid composition of coexisting components, and component
10 formulas related to physical gas-liquid contact such as a ratio L/G of an amount of absorption
liquid to an amount of exhaust gas, effective reaction height in an absorber, and an apparatus
structure.
For example, the following (A) and (B) can be used as the analysis performance formula.
YSO2out = f (G, YSO2in, [CaCO3], L, k) (A)
15 ηSO2 = g (G, YSO2in, [CaCO3], L, k) (B)
Here, YSO2out is a desulfurization apparatus outlet SO2 concentration, YSO2in is a
desulfurization apparatus inlet SO2 concentration, G is an amount of processed gas, [CaCO3]
is a concentration of CaCO3 in an absorber slurry, L is a slurry circulating flow rate, f and g
are functions representing characteristics of the desulfurization apparatus, ηSO2 is a
20 desulfurization ratio, and k is a reaction activity of the absorbent (dissolving rate). That is, the
desulfurization apparatus outlet SO2 concentration can be obtained by the function f with
respect to the input value. This function f may be realized by a chemical reaction model as
disclosed in Japanese Patent Application Laid-Open No. 59-199021 or Japanese Patent
Application Laid-Open No. 63-229126, or it is also possible to measure characteristics of an
25 actual desulfurization apparatus to be controlled under various operation conditions and to
model the characteristics by a method such as statistical processing.
In the soundness evaluation unit, the soundness of the desulfurization apparatus is
evaluated by performing comparison between the analytic performance and the measured
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performance corresponding thereto. In such evaluation of the soundness, the desulfurization
performance can be absolutely evaluated regardless of the actual operation state on the user
side, and the soundness can be accurately evaluated. The support information creation unit
creates the support information including at least one operation condition set based on the
evaluation result of the soundness evaluation unit and a balance forecast corresponding 5 to the
operation condition. By performing the operation based on the support information thus
created, the user can perform the economical operation while ensuring the soundness of the
desulfurization apparatus.
In the present specification, "analytic performance" broadly includes parameters
10 corresponding to performances that can be calculated by inputting the operation data to an
analytic performance formula (e.g., a simulation model).
[0011] (2) In some embodiments, in the configuration described above as (1), the support
information creation unit sets a plurality of the operation condition candidates based on the
evaluation result of the soundness evaluation unit and creates the support information by
15 obtaining the balance forecast corresponding to each of the operation condition candidates.
[0012] According to the configuration described above as (2), the plurality of the
operation condition candidates are set based on the soundness evaluation of the
desulfurization apparatus and the balance forecast is obtained for each operation condition
candidate. Thus, by comparing the balance forecasts of the plurality of the operation condition
20 candidates, it is possible to provide operation support advantageous to the economic benefit of
the user.
[0013] (3) In some embodiments, in the configuration described above as (1) or (2), the
support information creation unit obtains the balance forecast in consideration of expense
related to operation of the desulfurization apparatus and income from sale of byproducts
25 generated during the operation of the desulfurization apparatus.
[0014] According to the configuration described above as (3), it is possible to provide
operation support advantageous to the economic benefit of the user based on the balance
forecast in consideration of expense related to operation of the desulfurization apparatus and
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income from sale of byproducts generated during the operation of the desulfurization
apparatus.
[0015] (4) In some embodiments, in the configuration described above as (3), an
operation condition to be adopted is selected from the plurality of operation condition
candidates with priority given to minimizing 5 the expense.
[0016] According to the configuration described above as (4), the economic benefit of the
user can be optimized by selecting the operation condition so as to minimize expense factor
that occupies a large proportion in the balance of the user.
[0017] (5) In some embodiments, in the configuration described above as any one of (1)
10 to (4), the plurality of operation condition candidates are set so as to have different numbers
of circulation pumps for circulating absorption liquid to the desulfurization apparatus.
[0018] According to the configuration described above as (5), by calculating, predicting,
and comparing the apparent desulfurization performance and the operation cost in the case of
changing to the state of the operation condition candidate in which the number of circulation
15 pumps to be operated is different, it is possible to select the operation condition having the
number of circulation pumps to be operated that effectively brings the economic benefit to the
user while satisfying the performance. Since the circulation pumps occupy a relatively large
proportion of the utility power cost, adopting of such an operation condition makes it possible
to provide the operation support advantageous to the economic benefit of the user.
20 [0019] (6) In some embodiments, in the configuration described above as any one of (1)
to (5), the soundness evaluation unit evaluates the soundness by calculating the performance
ratio of the measured performance to the analytic performance and comparing the
performance ratio with a predetermined reference value.
[0020] According to the configuration described above as (6), the soundness evaluation
25 unit evaluates the soundness based on the performance ratio of the analytic performance and
the measured performance corresponding thereto. With such a performance ratio, the
desulfurization performance can be absolutely evaluated based on the measured performance
of the desulfurization apparatus, and the soundness including that in a predictive stage can be
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accurately evaluated. Therefore, even when an input amount of absorbent or a supply amount
of absorption liquid is excessively large at the discretion of the user, it is possible to
accurately and promptly detect the soundness of the desulfurization apparatus based on the
performance ratio.
[0021] (7) In some embodiments, in the configuration described above 5 as any one of (1)
to (6), the operation data is acquired from a local monitoring system via a network by a
remote support system arranged at a position geographically remote from the local monitoring
system capable of monitoring the desulfurization apparatus.
[0022] According to the configuration described above as (7), owing to that the remote
10 support system, arranged at the position remote from the local monitoring system arranged at
the site where the desulfurization apparatus is located, acquires the operation data used for
soundness evaluation via a network, the operation support system can support the operation of
the desulfurization apparatus in real time at the position remote from the site.
[0023] (8) In some embodiments, in the configuration described above as (7), the local
15 monitoring system includes a display portion capable of displaying the support information
acquired from the remote support system.
[0024] According to the configuration described above as (8), since the support
information is displayed on the display portion included in the local monitoring system
arranged at the user side, effective and rapid support for the user can be provided.
20 [0025] (9) To solve the abovementioned problem, an operation support method for a
desulfurization apparatus according to at least one embodiment of the present invention is an
operation support method for a desulfurization apparatus removing SO2 from exhaust gas by
using an absorbent, including steps of acquiring operation data of the desulfurization
apparatus, calculating an analytic performance concerning to a desulfurization performance of
25 the desulfurization apparatus based on the operation data, acquiring a measured performance
when acquiring the analytic performance, evaluating soundness of the desulfurization
apparatus by performing comparison between the analytic performance and the measured
performance, setting at least one operation condition candidate based on the evaluation result
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of soundness, obtaining a balance forecast corresponding to the operation condition candidate,
and creating support information including the operation condition candidate and the balance
forecast.
[0026] The method described above as (9) can be appropriately performed by each
operation support system (including the respective embodiments described 5 above) for the
desulfurization apparatus.
Advantageous Effects
[0027] According to at least one embodiment of the present invention, it is possible to
10 provide an operation support system and an operation support method for a desulfurization
apparatus capable of maximizing an economic benefit of a user due to operation of a plant
facility while ensuring soundness of the desulfurization apparatus.
BRIEF DESCRIPTION OF DRAWINGS
15 [0028] FIG. 1 is a schematic diagram illustrating an overall configuration of an operation
support system for a desulfurization apparatus according to an embodiment of the present
invention.
FIG. 2 is a schematic diagram illustrating an example of a configuration layout of a
local monitoring system, a network, and a remote support system of FIG. 1.
20 FIG. 3 is a block diagram functionally illustrating an internal configuration of a central
server in the remote support system of FIG. 2.
FIG. 4 is a flowchart illustrating, for each step, an operation support method to be
performed in the central server of FIG. 3.
FIG. 5 is a graph illustrating a change in a circulation amount of absorption liquid with
25 the number of absorption liquid circulation pumps to be operated.
FIG. 6 illustrates an example of support information created in step S7 of FIG. 4.
FIG. 7 illustrates an example of auxiliary information included in the support
information created in step S7 of FIG. 4.
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DETAILED DESCRIPTION
[0029] Embodiments of the present invention will now be described in detail with
reference to the accompanying drawings. It is intended, however, that unless particularly
identified, dimensions, materials, shapes, relative positions and the 5 like of components
described in the embodiments shall be interpreted as illustrative only and not intended to limit
the scope of the present invention.
For example, an expression of relative or absolute arrangement such as “in a direction”,
“along a direction”, “parallel”, “perpendicular”, “centered”, “concentric” and “coaxial” shall
10 not be construed as indicating only the arrangement in a strict literal sense, but also includes a
state where the arrangement is relatively displaced by a tolerance, or by an angle or a distance
whereby it is possible to achieve the same function.
Further, for example, an expression of a shape such as a rectangular shape or a
cylindrical shape shall not be construed as only the geometrically strict shape, but also
15 includes a shape with unevenness or chamfered corners within the range in which the same
effect can be achieved.
On the other hand, an expression such as “comprise”, “include”, “have”, “contain” and
“constitute” are not intended to be exclusive of other components.
[0030] FIG. 1 is a schematic diagram illustrating an overall configuration of an operation
20 support system 100 for a desulfurization apparatus 1 according to an embodiment of the
present invention. In the operation support system 100, the desulfurization apparatus 1
included in a predetermined plant facility is set as a support target, and in the following
embodiments, the case where remote support is performed at a point geographically remote
from the plant facility is described as an example.
25 [0031] The desulfurization apparatus 1 includes a dust collecting device 2 installed in
association with a boiler (not illustrated) of a plant facility such as a thermal power plant and
for collecting fine particles contained in exhaust gas G0 flowing through an exhaust passage
3a of the boiler, and an absorption tower 4 installed downstream of the dust collecting device
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2 in an exhaust passage 3b through which the exhaust gas G1 having passed through the dust
collecting device 2 flows.
[0032] The dust collecting device 2 is an electric dust collector that charges fine particles
contained in the exhaust gas G0 by performing corona discharging on the exhaust gas G0
supplied into a casing and collects dust by causing the fine particles to adhere 5 to positively
and negatively charged adhesion portions with electric attraction. The exhaust gas G1
subjected to a dust collecting process by the dust collecting device 2 is supplied to the
absorption tower 4 through the exhaust passage 3b.
[0033] The absorption tower 4 performs a desulfurization process by absorbing SO2
10 (sulfur dioxide) in the exhaust gas G1 by causing absorption liquid 6 containing limestone 10
to be in contact with the exhaust gas G1 subjected to the dust collecting process in the dust
collecting device 2. The absorption liquid 6 is stored in the bottom of the absorption tower 4.
The absorption liquid 6 is generated by mixing limestone 10 supplied from a limestone feeder
8 arranged outside the absorption tower 4 with water 12 supplied to the bottom of the
15 absorption tower 4.
[0034] The absorption liquid 6 stored in the bottom of the absorption tower 4 is pressurefed
by an absorption liquid circulation pump 14 and supplied to an upper portion in the
absorption tower 4 through an absorption liquid header 16 arranged outside the absorption
tower 4. The absorption liquid circulation pump 14 includes a plurality of pump units
20 connected in series or in parallel with each other, and is configured to be capable of variably
adjusting the flow rate of the absorption liquid 6 pressure-fed from the absorption liquid
circulation pump 14 by independently controlling an operation state of each pump unit. The
absorption liquid 6 thus supplied to the upper portion of the absorption tower 4 contacts the
exhaust gas G1 rising in the absorption tower 4 in a process of being sprayed and dropped
25 from a nozzles 18 provided in the upper portion of the absorption tower 4. As a result, SO2
contained in the exhaust gas G1 reacts with the limestone 10 in the absorption liquid 6, and
the desulfurization process is performed.
[0035] The following formula (1) is a chemical reaction formula of the desulfurization
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process carried out in the absorption tower 4. In the desulfurization process, the limestone 10
and SO2 contained in the exhaust gas G1 react with each other to generate gypsum 24 (CaCO4
•2H2O) as byproduct. The exhaust gas G2 from which SO2 has been removed is discharged
from the top of the absorption tower 4 to the outside through a desulfurization exhaust gas
5 pipe 25.
SO2+1/2O2+CaCO3+2H2O⇢CaCO4•2H2O+CO2 (1)
[0036] In addition, a part of the absorption liquid 6 stored in the bottom of the absorption
tower 4 is sent to a dehydrator 22 through an extraction pipe 20 branched from the absorption
liquid header 16 outside the absorption tower 4 while being pressure-fed by the absorption
10 liquid circulation pump 14. The dehydrator 22 is constituted by, for example, a belt filter, and
the absorption liquid 6 is dehydrated in a process of being conveyed by the belt filter, and the
generated gypsum 24 is discharged out of the system.
Note that the filtrate generated in the dehydration process in the dehydrator 22 is reused
by being supplied as the water 12 to the bottom of the absorption tower 4.
15 [0037] Further, an oxidation air 26 is supplied to the bottom of the absorption tower 4.
Thus, the oxidation air 26 is contained in the absorption liquid 6, so that oxidation of the
sulfurous acid group generated as being transferred from the SO2 exhaust gas into the
absorption liquid 6 to the sulfuric acid group is promoted, and as a result, the removal
efficiency of the SO2 in the exhaust gas is also improved.
20 [0038] Incidentally, an inlet-side SO2 concentration sensor 28 for detecting an SO2
concentration of the exhaust gas G1 to be taken into the absorption tower 4, i.e., the inlet-side
SO2 concentration, is installed in the exhaust passage 3b connecting the dust collecting device
2 and the absorption tower 4. An outlet-side SO2 concentration sensor 30 for detecting an SO2
concentration of the exhaust gas G2 discharged from the absorption tower 4, i.e., the outlet25
side SO2 concentration, is installed in the desulfurization exhaust gas outlet pipe 25. In
addition, a limestone concentration sensor 32 for detecting a limestone concentration of
absorption liquid 6 in the absorption tower 4 and a pH sensor 34 for detecting a pH value
thereof are installed in the absorption liquid header 16.
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[0039] The detected values of these sensors are input to a control unit (not illustrated) of
the desulfurization apparatus 1, and are used for operation control of the desulfurization
apparatus 1. Specifically, operations of the limestone feeder 8 and the absorption liquid
circulation pump 14, and supply of the oxidation air 26 are adjusted so that the detection
values of the sensors each fall within a predetermined range, whereby the 5 desulfurization
apparatus 1 is controlled so that a desired desulfurization performance is exhibited.
[0040] The plant facility in which the desulfurization apparatus 1 having such a
configuration is installed is provided with a local monitoring system 200 for monitoring the
desulfurization apparatus 1. The local monitoring system 200 is located on the same site
10 (within the site of the plant facility) as the desulfurization apparatus 1 to be monitored and is
configured to be capable of communicating with a remote support system 400 being
geographically remote via a network 300.
[0041] As illustrated in FIG. 1, the remote support system 400 is configured to be capable
of communicating with a plurality of the local monitoring systems 200 respectively installed
15 in a plurality of plant facilities via the network 300. Although the following description refers
primarily to one specific local monitoring system 200, the same applies to other local
monitoring systems 200 unless otherwise noted.
[0042] FIG. 2 is a schematic diagram illustrating an example of a configuration layout of
the local monitoring system 200, the network 300, and the remote support system 400 of FIG.
20 1.
[0043] The local monitoring system 200 includes a monitoring server 202 for collecting
operation data related to the desulfurization apparatus 1, a local server 204 for communicating
various information handled in the local monitoring system 200 with the remote support
system 400 via the network 300, and a client terminal 206 capable of accessing the local
25 server 204.
[0044] In the monitoring server 202, the operation data related to the desulfurization
apparatus 1 is collected by predetermined instruments at the installation site of the
desulfurization apparatus 1. The operation data includes, for example, the detected values of
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the sensors illustrated in Fig. 1 (specifically, the inlet-side SO2 concentration detected by the
inlet-side SO2 concentration sensor 28, the outlet-side SO2 concentration detected by the
outlet-side SO2 concentration sensor 30, the limestone concentration of the absorption liquid 6
detected by the limestone concentration sensor 32, the pH value of the absorption liquid 6
detected by the pH sensor 34, and the like), and control signals to the limestone 5 feeder 8, the
absorption liquid circulation pump 14, and a supply device (not illustrated) of the oxidation
air 26. The operation data collected by the monitoring server 202 is transmitted to the local
server 204 via a local network.
[0045] The operation data received from the monitoring server 202 at the local server 204
10 is transmitted to the remote support system 400 via the network 300 as real-time data. The
network 300 is connected, for example, through a dedicated line (Virtual Private Network:
VPN), and the local server 204 is connected to the network 300 through a VPN router 208.
[0046] The local server 204 may store the operation data acquired from the monitoring
server 202 as historical data for a predetermined period of time at a predetermined cycle. In
15 this case, the local server 204 may process the historical data into data at a predetermined
cycle and transmit the processed data to the remote support system 400 as real-time data.
[0047] The remote support system 400 is located geographically remote from the local
monitoring system 200, for example, in a site of a plant manufacturer that is a manufacturer of
plant equipment including the desulfurization apparatus 1, and is configured to communicate
20 with the local monitoring system 200 by being connected to the network 300 through a VPN
router 402. The remote support system 400 includes a central server 404 capable of
communicating various information handled in the remote support system 400 with the local
monitoring system 200 via the network 300 and a support terminal 406 capable of accessing
the central server 404. The central server 404 and the support terminal 406 are configured to
25 be capable of communicating with each other via a local network.
[0048] In the remote support system 400, remote assistance of the desulfurization
apparatus 1 is provided based on the operation data received from the local monitoring system
200 via the network 300. The operation data received by the central server 404 may be stored
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in a data storage server (not illustrated) in the remote support system 400.
[0049] The operation data transmitted to the central server 404 can be accessed from the
support terminal 406 as appropriate, and can be constantly checked by an operator for
operating the support terminal 406 (e.g., plant manufacturer maintenance expert residing in
the remote support 5 system 400).
[0050] The operator performs analysis based on the operation data transmitted to the
central server 404 using the support terminal 406, and transmits support information created
based on the analysis results to a user of the plant facility (at the local monitoring system 200
side) as required.
10 [0051] In the local monitoring system 200, the support information is received from the
remote support system 400 via the network 300. The support information received at the local
monitoring system 200 can be appropriately confirmed by the user on the client terminal 206
through the local server 204.
[0052] Subsequently, FIG. 3 is a block diagram functionally illustrating an internal
15 configuration of the central server 404 in the remote support system 400 of FIG. 2, and FIG. 4
is a flowchart illustrating, for each step, an operation support method to be performed in the
central server 404 of FIG. 3.
[0053] Here, at least a part of the internal configuration of the central server 404
illustrated in FIG. 3 may be distributed to the support terminal 406 constituting the remote
20 support system 400 or may be constructed in a cloud server.
[0054] The central server 404 of the remote support system 400 includes an operation
data input-acquisition unit 410 for acquiring the operation data of the desulfurization
apparatus 1, an analytic performance calculation unit 412 for calculating an analytic
performance P, a measured performance acquisition unit 414 for acquiring a measured
25 performance Pm when acquiring the analytic performance P, a soundness evaluation unit 416
for evaluating soundness of the desulfurization apparatus 1 by calculating a performance ratio
of the measured performance Pm to the analytic performance P, and a support information
creation unit 418 for creating the support information based on an evaluation result of the
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soundness evaluation unit 416.
[0055] First, the operation data input-acquisition unit 410 acquires the operation data of
the desulfurization apparatus 1 (step S1). As described above, the acquisition of the operation
data by the operation data input-acquisition unit 410 is performed by receiving the real-time
data transmitted from the local monitoring system 200 via 5 the network 300.
[0056] The operation data acquired by the operation data input-acquisition unit 410
includes at least an amount of the absorbent. Here, the amount of the absorbent is, for
example, a supply amount of the limestone 10 from the limestone feeder 8, and can be
acquired by including the control signal to the limestone feeder 8 in the desulfurization
10 apparatus 1 in the operation data. In this case, the supply amount of limestone 10 included in
the operation data may be an amount necessary and sufficient to neutralize SO2 (sulfur
dioxide) in the exhaust gas G1 to be contacted with the absorption liquid 6, or may be an
amount including a marginal amount added to the amount necessary and sufficient to
sufficiently neutralize SO2 (sulfur dioxide) in the exhaust gas G1.
15 [0057] The amount of the absorbent included in the operation data may be an amount of
the absorbent (limestone 10) remaining in the absorption liquid 6. In this case, the remaining
amount of the absorbent can be acquired as, for example, a limestone concentration of the
absorption liquid 6 detected by the limestone concentration sensor 32.
[0058] As described above, the operation data acquired by the operation data input20
acquisition unit 410 can broadly include the detected values of the sensors (specifically, the
inlet-side SO2 concentration detected by the inlet-side SO2 concentration sensor 28, the outletside
SO2 concentration detected by the outlet-side SO2 concentration sensor 30, the limestone
concentration of the absorption liquid 6 detected by the limestone concentration sensor 32,
and the pH value of the absorption liquid 6 detected by the pH sensor 34) and the control
25 signals to the limestone feeder 8, the absorption liquid circulation pump 14, and the supply
device (not illustrated) of the oxidation air 26.
[0059] Subsequently, the analytic performance calculation unit 412 calculates at least one
analytic performance P based on the operation data acquired by the operation data input-
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acquisition unit 410 (step S2). The analytic performance P is calculated arithmetically as a
parameter related to the desulfurization performance of the desulfurization apparatus 1. Here,
an analytic performance formula is composed of constituent formulas related to chemical
reactions such as residual concentration of the absorbent, an SO2 absorbed amount, a pH
value, liquid composition of coexisting components, based on the operation 5 data, and
constituent formulas related to physical gas-liquid contact such as a ratio L/G of an exhaust
gas amount and a absorption liquid amount, effective reaction height in an absorber, an
apparatus construction, and the like, and is set by comprehensively considering factors that
may affect the desulfurization performance with respect to the amount of absorbent, for
10 example.
[0060] The arithmetic formula to be used to determine the analytic performance P in step
S2 is defined by a function having parameters included in the operation data acquired by the
operation data input-acquisition unit 410 as variables, and allows parameter evaluation based
on the actual operation data. Such a function is defined by evaluating correlations between the
15 analytic performance P and each variable by a theoretical, experimental, or simulated method.
Such an arithmetic formula may be stored in advance in a storage device (not illustrated) of
the remote support system 400, or may be appropriately input by the operator of the remote
support system 400.
[0061] The analytic performance P may be any parameter related to the desulfurization
20 performance, and for example, a desulfurization ratio may be employed. Adopting the
desulfurization ratio as the analytic performance P is preferable because soundness of the
desulfurization apparatus 1 can be evaluated comprehensively, easily and accurately. Such an
analytic performance may be calculated based on at least one of the structural parameter of
the desulfurization apparatus 1 and the chemical reaction parameter of the absorbent (such as
25 the limestone 10). This enables accurate estimation of the analytic performance concerning to
the desulfurization performance from structural or chemical reactive aspects.
[0062] Subsequently, the measured performance acquisition unit 414 acquires the
measured performance Pm corresponding to the analytic performance P calculated by the
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analytic performance calculation unit 412 (step S3). For example, when the analytic
performance P corresponds to the desulfurization ratio as described above, the measured
performance acquisition unit 414 acquires the measured performance Pm of the
desulfurization ratio using the inlet-side SO2 concentration detected by the inlet-side SO2
concentration sensor 28 and the outlet-side SO2 concentration detected by the 5 outlet-side SO2
concentration sensor 30.
[0063] Subsequently, the soundness evaluation unit 416 evaluates the soundness of the
desulfurization apparatus 1 by comparing the analytic performance P calculated by the
analytic performance calculation unit 412 with the measured performance Pm acquired by the
10 measured performance acquisition unit 414 (step S4). Such soundness evaluation may be
performed, for example, by calculating a performance ratio R, which is the ratio of the
analytic performance P and the measured performance Pm, and determining whether or not
performance degradation has occurred in the desulfurization apparatus 1 based on whether or
not the performance ratio R is within an acceptable range defined by a predetermined
15 reference value R0. The performance ratio R calculated in this manner is an index capable of
absolutely evaluating the soundness of the desulfurization performance regardless of the
operation state of the desulfurization apparatus 1 (for example, even when the apparent
desulfurization ratio behaves so as to satisfy the threshold by setting the supply amount of the
limestone 10 excessively on the user side).
20 [0064] In this case, the reference value R0 serving as an evaluation reference of the
performance ratio R may be set according to specifications of the desulfurization apparatus 1
to be evaluated. As illustrated in FIG. 1, the remote support system 400 is connected to a
plurality of different desulfurization apparatuses 1 via the network 300. Each of the
desulfurization apparatuses 1 has inherent characteristics (habits) to no small extent. Such
25 inherent characteristics may be reflected in the performance evaluation by selecting the
reference value R0 corresponding to the desulfurization apparatus 1 to be evaluated from
among the reference values corresponding to the apparatuses stored in the database in advance.
[0065] Here, the inherent characteristics (habits) of the desulfurization apparatus 1 may
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include not only initial characteristics but also a change in the performance evaluation result
due to a change with time (ash stain, change in the type of coal, pump wear, etc.).
[0066] When the soundness of the desulfurization apparatus 1 is ideal, the analytic
performance P and the measured performance Pm are equal to each other, and thus the
performance ratio R becomes "1". On the other hand, when the 5 soundness of the
desulfurization apparatus 1 deviates from the ideal condition, a considerable difference occurs
between the analytic performance P and the measured performance Pm, and thus the
performance ratio R has a value deviating from "1". The reference value R0 is set as a
threshold value for determining how much the performance ratio R deviates from the normal
10 value "1" to determine that the soundness is impaired. For example, in the case where the
reference value R0 is set to allow an error of up to -20% from the normal value "1" and when
the performance ratio R is less than 0.8, the true performance based on the operation condition
is apparently degraded and is determined to be in an unsound state.
[0067] Here, the performance ratio R used in the soundness evaluation may be a ratio
15 between a logarithmic value of the analytic performance P and a logarithmic value of the
measured performance Pm. In the desulfurization apparatus 1 having a high desulfurization
performance (i.e., a desulfurization apparatus having a large SO2 concentration differential
between the inlet and the outlet), the use of a linear ratio as the performance ratio R results in
a peaky property, and thus the use of a logarithmic ratio enables accurate diagnosis with high
20 sensitivity.
[0068] Subsequently, at least one operation condition candidate is selected within the
allowable range of the soundness of the desulfurization apparatus 1 (step S5). Here, the
operation condition candidate means an operation condition that can be selected within a
range in which the soundness of the desulfurization apparatus 1 evaluated in step S4 can be
25 maintained in a favorable state. Such an operation condition candidate may include the
current operation condition and may only be the current operation condition if there is no
other possible operation condition. On the other hand, if there is another possible operation
condition, the number of candidates may be arbitrary and may be singular or plural.
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[0069] In the present embodiment described below, description will be provided on an
example of operation condition candidates in which three operation condition candidates 1 to
3 each having different number of the absorption liquid circulation pumps 14 to be operated
are selected, which significantly affect a utility power cost of the desulfurization apparatus 1.
FIG. 5 is a graph illustrating a change in the circulation amount of the absorption 5 liquid 6 with
the number of the absorption liquid circulation pumps 14 to be operated. Since the change in
the number of the absorption liquid circulation pumps 14 to be operated significantly affects
the utility power cost of the desulfurization apparatus 1, it is possible to realize an economical
operation that can minimize the utility power cost of the desulfurization apparatus 1 by
10 selecting the operation condition candidate with a different number thereof to be operated.
[0070] Here, in the case where the absorption liquid circulation pump 14 is a variable
capacity type, it is also possible to select the operation condition candidates each having a
different capacity of the absorption liquid circulation pump 14. Further, in the case where the
absorption liquid circulation pump 14 performs flow rate control of the absorption liquid 6
15 with rotation speed control by an inverter or movable blade control, the operation condition
candidates in which the rotation speed control amount or the movable blade control amount is
different may be selected.
[0071] Here, whether or not the soundness can be maintained in a favorable state in each
operation condition candidate is determined, for example, by estimating how the analytic
20 performance calculated in step S2 and the reference value set in step S3 change in each
operation condition.
[0072] Further, the operation condition candidate may be selected on the condition that
quality of the gypsum 24 generated as byproducts with the desulfurization reaction in the
desulfurization apparatus 1 can be secured to a certain level or higher. The byproducts such as
25 the gypsum 24 generated in the desulfurization apparatus 1 may be sold to a third party to
serve as an income factor of a user. However, in order to sale them to a third party, a certain
level or higher of quality desired by the third party is required. Therefore, the operation
condition candidate may be added with a condition not only that the soundness of the
20
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desulfurization apparatus 1 can be maintained in a favorable state but also that the quality of
byproducts can be sufficiently ensured. In particular, in selecting the operation condition
candidate, it is also conceivable to maintain the soundness by increasing a calcium carbonate
concentration in the absorption liquid 6. However, in this case, it should be noted that calcium
carbonate in gypsum is increased due to excessive increase of the 5 calcium carbonate
concentration and gypsum purity is lowered, or that a gypsum moisture content is increased
due to increase of fine particles, which may be lower than take-up quality of a gypsum trader.
[0073] Subsequently, a balance forecast is calculated for each operation condition
candidate set in step S5 (step S6). The balance forecast is the balance predicted when the
10 desulfurization apparatus 1 is operated according to each operation condition candidate, and is
calculated as a total operating cost by considering expense related to the operation of the
desulfurization apparatus 1 and income from sale of byproducts generated during the
operation of the desulfurization apparatus 1.
[0074] The expense includes cost items required when operating the desulfurization
15 apparatus 1 in accordance with each operation condition candidate, and includes, for example,
a utility power cost, a chemical cost and an environmental charge. These cost items are
calculated based on corresponding conversion rates. For example, the cost items such as the
utility power cost, the chemical cost, and the environmental charge are calculated based on an
electricity rate, a fuel and raw material rate, and an environmental charge rate, respectively.
20 [0075] On the other hand, the income includes income items according to sale of the
byproducts generated during operation of the desulfurization apparatus 1, and includes, for
example, sale profits of the gypsum 24 and FLYASH. The sale profits are calculated based on
sale rates corresponding to sale objects. For example, sale profits for gypsum and FLYASH
are calculated based on their sale rates respectively.
25 [0076] As the cost items and the rates used for calculating sale profits, information stored
in a database in advance may be used, a value appropriately input by an operator may be used,
or information acquired from the outside via, for example, a network may be used. Such rates
are preferably updated at predetermined timing.
21
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[0077] Subsequently, the support information creation unit 418 creates the support
information including the operation condition candidate selected in step S5 and the balance
forecast calculated in step S6 (step S7), and displays the support information on the support
terminal 406 (step S8). Here, FIG. 6 illustrates an example of the support information created
in step S7 of FIG. 4. In this example, the operation condition candidates 1 to 5 3 selected in step
S5 are illustrated, and "utility power (expense)", "income (profit)", and "total operating cost
(total balance)" are illustrated as the balance forecast corresponding to each operation
condition candidate.
[0078] In addition to the balance forecast described above, the support information may
10 also include auxiliary information for selecting an optimal operation condition from the
operation condition candidates. FIG. 7 illustrates an example of the auxiliary information
included in the support information created in step S7 of FIG. 4. In FIG. 7, the respective
parameters indicating the state of the exhaust gas G1 to be subjected to the desulfurization
process are illustrated as auxiliary information 1. Specifically, the instantaneous values of a
15 boiler load located upstream the desulfurization apparatus 1, a flow rate of the exhaust gas G1,
and the inlet SO2 concentration, the outlet SO2 concentration, inlet gas temperature, outlet gas
temperature, and inlet gas pressure of desulfurization apparatus 1 are illustrated, respectively.
Further, the parameters indicating the operation state of the desulfurization apparatus 1 are
illustrated as auxiliary information 2. Specifically, the presently indicated values of a level of
20 the absorption liquid 6 in the absorption tower 4, the number of operating absorption liquid
circulation pumps 14, the pH value and the liquid specific gravity of the absorption liquid 6,
the flow rate of the oxidation air 26 are illustrated, respectively. Further, rates serving as the
basis for calculating the utility power cost and income are illustrated as auxiliary information
3. Specifically, an environmental charge rate, a power rate, a fuel rate, a raw material rate, and
25 sale rates for gypsum and FLYASH are illustrated, respectively.
[0079] Such support information is displayed on the support terminal 406 of the remote
support system 400 and is recognized by the operator of the support terminal 406. By
referring to the support information displayed on the support terminal 406, the operator
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recognizes the current state of the desulfurization apparatus 1 and selects the appropriate
operation condition for the user from the operation condition candidates (step S9).
[0080] A selection reference of the operation condition in step S9 is set by
comprehensively considering the balance information and the parameters included in the
support information. When emphasis is placed on keeping the total operating 5 cost low,
operation condition candidate 3 having the lowest total operating cost is selected in the
example of Fig. 6. When emphasis is placed on keeping the utility power cost low, operation
condition candidate 3 having the lowest utility power cost is selected. When emphasis is
placed on securing a large amount of income, operation condition candidate 1 having the
10 largest income is selected.
[0081] In a system such as a power generation plant where the main business is selling
electricity to the outside, maximizing the amount of electricity selling is prioritized. In
addition, a selling price of the gypsum 24 being byproducts of the desulfurization apparatus 1
is lower than the electricity selling price. In view of these circumstances, it is possible to
15 select an operation condition that maximizes the user's business benefit by selecting the
operation condition candidate that minimizes the utility power cost (expense).
[0082] In the selection of the operation condition candidate, by considering the auxiliary
information included in the support information, an operation condition suitable for the user
may be selected in consideration of various factors not limited to the balance information.
20 This makes it possible to make comprehensive determination considering not only the simple
balance but also the operation state of the boiler and the desulfurization apparatus 1 in the
background or external factors such as the environmental charge rate and sale rate of
byproducts.
[0083] In particular, since sale of the gypsum 24, which is an element of the income, is
25 often performed batchwise, it may be considered that there is some gap between the current
sale rate and the actual rate at sale.
[0084] Further, the selection reference of the operation condition in step S9 may be set to
be variable in accordance with the surrounding environment. For example, a selection
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reference for the operation condition prioritizing the soundness may be adopted when the
environmental charge rate is high, and a cost-oriented selection reference prioritizing the total
operating cost over the soundness may be adopted when the environmental charge rate is low.
This enables the selection of an operation condition that provides an economic benefit in total
while ensuring the soundness of the desulfurization apparatus 1 in accordance 5 with changes in
the surrounding environment. This is effective in improving user’s profitability.
[0085] Here, the selection of the operation condition in step S9 may be performed by an
artificial determination of the operator of the support terminal 406, or may be performed
automatically by the central server 404 or the support terminal 406.
10 [0086] Subsequently, the operation condition selected by the support terminal 406 is
transmitted to the local monitoring system 200 via the network 300 and displayed on the
client terminal 206 (step S10). Thus, the operation condition selected by the operator of the
remote support system 400 is displayed on the client terminal 206. The user recognizes the
operation condition displayed on the client terminal 206 and executes operation in accordance
15 with the operation condition, thereby enabling economical operation of the desulfurization
apparatus 1.
[0087] In the present embodiment, description is provided on the case where the operator
selects the operation condition while the support information created in step S7 is displayed
on the support terminal 406 side of the remote support system 400. However, the support
20 information created in step S7 may be directly displayed on the client terminal 206 to give the
user side a right to select operation condition.
[0088] As described above, according to the above-described embodiment, the soundness
of the desulfurization apparatus 1 is monitored at the remote support system 400 and the
appropriate operation condition is selected for the user, so that the plant operation on the user
25 side can be remotely supported. Such selection of the operation condition is performed in
accordance with needs of the user within a range in which the soundness of the
desulfurization apparatus 1 can be secured. Even when the fuel type of the desulfurization
apparatus 1 is changed or the like, it is possible to effectively support the economic operation
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that maximizes the profitability of the user in consideration of the surrounding environment.
Industrial Applicability
[0089] At least one embodiment of the present invention is available for an operation
support system and an operation support method for a desulfurization 5 apparatus using
absorbent to remove SO2 in exhaust gas.
Reference Signs List
[0090]
10 1 Desulfurization apparatus
2 Dust collecting device
3a, 3b Exhaust passage
4 Absorption tower
6 Absorption liquid
15 8 Limestone feeder
10 Limestone
12 Water
14 Absorption liquid circulation pump
16 Absorption liquid header
20 18 Nozzle
20 Extraction pipe
22 Dehydrator
24 Gypsum
25 Desulfurization exhaust gas pipe
25 26 Oxidation air
100 Operation support system
200 Local monitoring system
202 Monitoring server
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17-02067PCT_specification
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204 Local server
206 Client terminal
300 Network
400 Remote support system
404 5 Central server
406 Support terminal
410 Operation data input-acquisition unit
412 Analytic performance calculation unit
414 Measured performance acquisition unit
10 416 Soundness evaluation unit
418 Support information creation unit
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CLAIMS
1. An operation support system for a desulfurization apparatus removing SO2 from exhaust
gas by using an absorbent, comprising:
an operation data input-acquisition unit configured to acquire operation 5 data of the
desulfurization apparatus;
an analytic performance calculation unit configured to calculate an ideal analytic
performance concerning to a desulfurization performance of the desulfurization apparatus
based on the operation data acquired by the operation data input-acquisition unit;
10 a measured performance acquisition unit configured to acquire a measured performance
when acquiring the analytic performance;
a soundness evaluation unit configured to evaluate soundness of the desulfurization
apparatus by calculating a performance ratio of the measured performance acquired by the
measured performance acquisition unit to the analytic performance calculated by the analytic
15 performance calculation unit; and
a support information creation unit configured to create support information including at
least one operation condition candidate set based on an evaluation result of the soundness
evaluation unit and a balance forecast corresponding to the operation condition candidate.
20 2. The operation support system for a desulfurization apparatus according to claim 1,
wherein the support information creation unit sets a plurality of the operation condition
candidates based on the evaluation result of the soundness evaluation unit and creates the
support information by obtaining the balance forecast corresponding to each of the operation
condition candidates.
25
3. The operation support system for a desulfurization apparatus according to claim 1 or 2,
wherein the support information creation unit obtains the balance forecast in consideration of
expense related to operation of the desulfurization apparatus and income from sale of
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- 27 -
byproducts generated during the operation of the desulfurization apparatus.
4. The operation support system for a desulfurization apparatus according to claim 3,
wherein an operation condition to be adopted is selected from the plurality of operation
condition candidates with priority given to minimizing 5 the expense.
5. The operation support system for a desulfurization apparatus according to any one of
claims 1 to 4, wherein the plurality of operation condition candidates are set so as to have
different numbers of circulation pumps to be operated for circulating absorption liquid to the
10 desulfurization apparatus.
6. The operation support system for a desulfurization apparatus according to any one of
claims 1 to 5, wherein the soundness evaluation unit evaluates the soundness by calculating
the performance ratio of the measured performance to the analytic performance and
15 comparing the performance ratio with a predetermined reference value.
7. The operation support system for a desulfurization apparatus according to any one of
claims 1 to 6, wherein the operation data is acquired from a local monitoring system via a
network by a remote support system arranged at a position geographically remote from the
20 local monitoring system capable of monitoring the desulfurization apparatus.
8. The operation support system for a desulfurization apparatus according to claim 7,
wherein the local monitoring system includes a display portion capable of displaying the
support information acquired from the remote support system via the network.
25
9. An operation support method for a desulfurization apparatus removing SO2 from
exhaust gas by using an absorbent, comprising steps of:
acquiring operation data of the desulfurization apparatus;
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calculating an analytic performance concerning to a desulfurization performance of the
desulfurization apparatus based on the operation data;
acquiring a measured performance when acquiring the analytic performance;
evaluating soundness of the desulfurization apparatus by performing comparison
between the analytic performance and the measured 5 performance;
setting at least one operation condition candidate based on an evaluation result of the
soundness;
obtaining a balance forecast corresponding to the operation condition candidate; and
creating support information including the operation condition candidate and the
10 balance forecast.