Boiler Turbine Control Basis
-
Upload
walid-salama -
Category
Technology
-
view
1.518 -
download
8
description
Transcript of Boiler Turbine Control Basis
![Page 1: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/1.jpg)
1
BOILER / TURBINE CONTROL BASICS
![Page 2: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/2.jpg)
I. TYPE OF CONTROL
1. BOILER – A. ANALOG CONTROL INTENSIVE AND COMPLICATED (FOR ALL TYPES)
B. DIGITAL CONTROLS
GAS OIL FIRED
SOLID FUEL FIRED
FLUIDIZED COMB.
VERY CRITICAL CRITICAL CRITICAL
C. MONITERINGI. SWASII. STACK GAS MONITORING
![Page 3: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/3.jpg)
2. TURBINE – A. ANALOG CONTROLS – LESS COMPLICATED & FEW IN NOS
B. DIGITAL CONTROLS – VERY CRITICAL & FOR TRIP & DRIVE CONTROLC. TSI & GOVERNOR CONTROLS – VERY CRITICAL WITH RESPECT TO CONTROL AND SPEED OF RESPONSE
![Page 4: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/4.jpg)
II. FAIL SAFE PHILOSOPHY OF CONTROL (FOR BOILER + TURBINE)
FAIL SAFE:1. INTERLOCKS / SHUTDOWN2. TRANSMITTERS / SENSORS3. FINAL CONTROL ELEMENTS
TYPE OF FAILSAFE POSITIONS
1. FAIL OPEN2. FAIL CLOSE3. STAYPUT
FAIL OPEN / FAIL CLOSE IN CONTROL VALVES
1. ON SIGNAL FAILURE2. ON POWER AIR FAILURE
STAYPUT:ON POWER AIR FAILURE
![Page 5: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/5.jpg)
REDUNDANCY REQUIREMENTS
MOST OF THE EMERGENCY CONTROL SYSTEMS ARE STATIC.
i.e. THEY JUST REMAIN WITHOUT OPERATING FOR QUITE SAME TIME.
HOW ARE WE SURE THAT THE SYSTEM OPERATES WHEN IT IS REQUIRED TO OPERATE?
![Page 6: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/6.jpg)
I. IN NORMAL LIFE FOLLOWING ARE FEW EXAMPLES
1. UPS / diesel engine operation on failure of EB supply. 2. A fuse to blow on high current or short circuit. 3. An umbrella to unfold on sudden rain. 4. Kerosene stove to light on when gas cylinder getting emptied at home. 5. Torchlight to light while power is off. 6. Fire fighting co2 cylinder to open while fire catches up in a public place like cinema theatre. 7. Alarm clock to work for a critical early morning wakeup. 8. A relay to energize and trip the equipment on faulty condition.
![Page 7: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/7.jpg)
II. TO IMPROVE ON THE DEPENDABILITY OF
THE CONTROL SYSTEM IT IS NORMALLY
HELD IN ENERGIZED CONDITION AND DE-
ENERGIZED DURING A FALLTY CONDITION.
![Page 8: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/8.jpg)
A. SAFE FAILURES
These are called safe failuresOR
FALSE TRIPSOR
NUISANCE TRIPSSince they stop the process unnecessarilyThese faults REDUCE THE AVAILABILITY AND
CAUSE PRODUCTION LOSS
A wire opens
Output De-energizes
Processshutdown
I.
Fault in system
Output De-energizes
Processshutdown
II.
![Page 9: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/9.jpg)
B. DANGEROUS FAILURESFaults that cause the outputs to remain Energized are generally not detected and are Considered “DANGEROUS FAILURES” Because the system cannot tell the difference Between ‘Normal Operation’ and ‘Failure’And therefore cannot take the process to aSafe state when required to do so.
FAULT TOLERENCE“Ability to tolerate a single failure and Continue to operate”.
Can be implemented using various redundancySchemes.
![Page 10: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/10.jpg)
CHARACTERISTICS OF SYSTEM ARCHTECTURES FOR SAFETY SHUTDOWN
A 10011 Out Of 1
S
Process
WHEN A FAILS, PLANT TRIPS:
SAFETY - LOW
AVAILABILITY - LOW
![Page 11: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/11.jpg)
B
1 Out Of 2S
Process
WHEN ‘A’ OR ‘B’ FAILS, PLANT TRIPS:
SAFETY - V.HIGH
AVAILABILITY - LOW
A
1002
![Page 12: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/12.jpg)
B2 Out Of 2
S
Process
WHEN A & B FAIL THE PLANT TRIPS:
SAFETY - LOW
AVAILABILITY – V.HIGH
A 2002
![Page 13: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/13.jpg)
Process
A
S
B
C
WHEN 2 (OR 3) OUT OF THE THREE (A,B,C)
FAIL THEN ONLY PLANT TRIPS:
SAFETY - HIGH AVAILABILITY - HIGH
2 Out Of 3
2003
![Page 14: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/14.jpg)
SAFETY AVAILABILITY
1001 SINGLE TRANSMITTER LOW LOW
1002 2 OUT OF 1 TRANSMITTER AVERAGE HIGH
2003 2 OUT OF 3 TRANSMITTER HIGH HIGH
REDUNDANCYAT SENSOR LEVEL FOR ANALOG SIGNALS
![Page 15: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/15.jpg)
1002
FT1
FT2
> OUTPUT
HIGH
SELECTION
![Page 16: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/16.jpg)
2003
FT1
FT2
MID VALUE
SELECTIONOUTPUT
FT3
![Page 17: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/17.jpg)
REDUNDANCY IN CONTROL SYSTEM
1. REDUNDANCY IN DCS / PLC
a) AT PROCESSER LEVEL
b) AT POWER SUPPLY LEVEL
c) AT COMMUNICATION LEVEL
d) AT I/O LEVEL
e) AT OPERATOR STATION LEVEL
![Page 18: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/18.jpg)
CONTROLLER AND DATA
ACQUISITION SYSTEM
I/O MODULES
OPERATING & ENGINEERING STATION(BOP)
OPERATING STATION(BOILER)
CONTROLLER AND DATA
ACQUISITION SYSTEM
LOG PRINTERALARM &EVENT PRINTER
OPERATING STATION(TURBINE)
![Page 19: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/19.jpg)
![Page 20: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/20.jpg)
BASICS OF CLOSE LOOP CONTROLS
![Page 21: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/21.jpg)
In order to achieve proper automatic
control of a process, it is necessary to know the
characteristics of the process material itself,
as well all the devices used for process control.
A given process might require the control
of temperature, pressure, density and level,etc,.
Also regulating one variable can affect
other variables.
![Page 22: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/22.jpg)
For example, regulating temperature in a
process might affect the pressure and the
density.
Regulating the flow rate of material to a
process may also affect the level of material in
storage vessel.
It is important, therefore, to select a
controlling device which most accurately affects
the variable to be controlled.
![Page 23: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/23.jpg)
ON – OFF CONTROL
In this control, when the value of the
measured or controlled variable is at or above
the SP, the final control element is closed. When
the range is below the SP, the final control
element is open.
A common example of ON – OFF control action
is a thermostat. Consider the thermostat is set
for 68.F. If the temperature drops below 68
.F,
the heating unit is actuated.
![Page 24: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/24.jpg)
0%
100%
FE CLOSED
FE OPEN
RANGE OF
MEASUREMENT SP
OFF
ON
ON-OFF CONTROL
![Page 25: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/25.jpg)
ON-OFF CONTROL
![Page 26: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/26.jpg)
PROPORTIONAL ACTION
This action provides the control valve with
variant positions between ON and OFF. The
position of the FCE is not simply open or closed,
but varies, depending on how much the value of
the measured variable is above or below the SP.
The amount of energy to the process varies
accordingly.
![Page 27: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/27.jpg)
Its actuating output is proportional to the
error signal.
c(t) = Kce(t) + Cs
where, c(t) - controller output
Kc – proportional gain of the controller
e(t) - error signal
Cs – controller’s bias signal (i.e, its
actuating signal when e(t)=0)
![Page 28: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/28.jpg)
A proportional controller is described by
the value of its proportional gain Kc or
equivalent by its proportional band PB, where
PB=100/Kc.
The proportional band characterizes the range
over which the error must change in order to
drive the actuating signal of the controller over
its full range .
usually,
1 < PB < 500
![Page 29: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/29.jpg)
0%
RANGE OF
MEASUREMENT
100%FINAL ELEMENT
FULLY CLOSED
FINAL ELEMENT
FULLY OPEN
INTERMEDIATE
POSITIONING OF FCESP
PROPORTIONAL CONTROL
![Page 30: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/30.jpg)
PROPORTIONAL CONTROL ACTION
![Page 31: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/31.jpg)
LT
CONTROLLER
TANKSP
P CONTROLLER
e
+-
![Page 32: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/32.jpg)
PROPORTIONAL ACTION WITH RESET
This action enables the FCE to assume
intermediate position. In addition, it can shift
the relationship between the FCE and the value of
the measured or controlled variable. The
controller continues the corrective positioning
of the FCE until the measured variable returns to
the desired valve.
![Page 33: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/33.jpg)
Its actuating signal is related to the error
by the equation
c(t) = kce(t) + e(t)dt + Cs
where, TI – Integral time constant or reset time,
in min.
The reset time is an adjustable parameter and is
sometimes referred to as minutes per repeat.
Usually it varies in the range
0 < TI < 50 min
0
t kc
TI
![Page 34: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/34.jpg)
Some manufacturers do not calibrate their
controllers in terms of TI but in terms of its
reciprocal, 1/TI (repeats/min), which is known as
reset rate.
Consider the error changes by a step of magnitude
e.Initially the controller output is Kce (the
contribution of the integral term is zero). After
a period of TI min the contribution of the
integral term is
kc
TI
e(t)dt0
TI kc
TI
= eTI = kce
![Page 35: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/35.jpg)
It is clear from the above equation that
the integral control has repeated the response of
the proportional action. This repetition takes
place every TI min and has lent its name to the
reset time.
![Page 36: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/36.jpg)
PROPORTIONAL-PLUS-RESET ACTION
Cs
Cs + kce
Cs + 2kce
Cs + 3kce
0 TI 2TITime
c(t)
![Page 37: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/37.jpg)
PI CONTROLLER
CONTROLLER
DPCELL
FLOW
SPe
FLOW ELEMENT
![Page 38: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/38.jpg)
PROPORTIONAL ACTION WITH RESET
AND DERIVATIVE
Derivative, or rate action, adds even more
flexibility to the movement of the FCE. Response
is slow in same processes because a long period
of time is needed to detect and correct changes
in the measured variable. Derivative action
provides correct positioning of the FCE related
to the rate at which the value of the manipulated
variable is changing.
![Page 39: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/39.jpg)
The output of this controller is given by
where, TD – Derivative time constant,in min. With
the presence of derivative term(de/dt), the PID
controller anticipates what the error will be in
the immediate future and applies a control action
which is proportional to the current rate of
change of error.
c(t) = kc e(t) + e(t)dt + kcTD + Cs
kc
TI0
t de
dt
![Page 40: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/40.jpg)
Due to this property, the derivative control
action is sometimes referred to as anticipatory
control.
DRAW BACKS OF DERIVATIVE CONTROL ACTION:
For a response with constant non zero error
it gives no control action since de/dt=0.
For a noisy response with almost zero error
it can compute control action, although it is not
needed.
![Page 41: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/41.jpg)
PID CONTROLLER
TO
PROCESS
STEAM HDR
SPRAY
WATER
TE
TT
PT
DSHPRV
STEAM FROM BOILER
![Page 42: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/42.jpg)
FEATURES OF CONTROLLERS
PROPORTIONAL CONTROLLER
• Accelerates the response of a controlled
process.
• Produces an offset (i.e, non zero steady
state error) as a result of sustained load
change.
![Page 43: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/43.jpg)
• Eliminates any offset.
• Produces sluggish, long oscillating
responses.
• If we increase the gain Kc to produce faster
response, the system becomes more
oscillatory and may lead to instability.
INTEGRAL CONTROLLER
![Page 44: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/44.jpg)
DERIVATIVE CONTROLLER
• Anticipates future errors and introduces
appropriate action.
• Introduces a stabilizing effect on the
closed loop response of a process.
![Page 45: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/45.jpg)
SELECTING THE TYPE OF CONTROLLER
Following rules can be adopted in selecting the
most appropriate controller for a process.
1. If possible, use proportional controller.
Proportional controller can be used if
we can achieve
acceptable offset with moderate values of
Kc
P Controller is recommended for liquid level
control where there is not sustained load change.
![Page 46: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/46.jpg)
2. If a simple P controller is unacceptable,
use PI controller.
A PI controller should be used when
proportional control alone cannot provide
sufficiently small steady state errors
(offsets).
Therefore, PI will be generally used in
liquid level systems where there is
sustained load change and also for flow
control.
![Page 47: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/47.jpg)
The response of a flow control system is
rather fast.
Consequently, the speed of the closed loop
system remains satisfactory despite the
slowdown caused by the integral control
mode.
![Page 48: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/48.jpg)
3. Use a PID controller to increase the speed
of the closed loop response.
The PI eliminates the offset but reduces
the speed of the closed-loop response. For
a multicapacity process whose response is
very sluggish, the addition of a PI
controller makes it even more sluggish.
![Page 49: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/49.jpg)
In such cases the addition of the
derivative control action with its
stabilizing effect allows the use of
higher gains which produce faster
responses without excessive oscillations.
Derivative action is recommended for
temperature and composition control.
![Page 50: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/50.jpg)
![Page 51: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/51.jpg)
ANALOGY OF PID CONTROLLER
![Page 52: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/52.jpg)
Consider 2 cars ‘A’ and ‘B’ running on a main
road.
OBJECTIVE : Driver of car A aims at running his
car along with car B ( i.e., car B’s position is
the Set Point) say, speed of B is 50 km/h.
A
B
50 km/h
50 km/h
![Page 53: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/53.jpg)
PROPORTIONAL ACTION
Consider driver A is a proportional
controller.Therefore, whenever speed of B
changes A’s speed will change according to
the distance between A and B. Assume B’s
speed changes to 60 km/h(Load change)
which means in 1 hr B will be ahead of A
by 10 km. A’s speed changes according to
the distance between A and B say 1 km/h
increase per 1 km of distance.
![Page 54: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/54.jpg)
So A’s speed goes on increasing and B goes
more and more away from A. At one
point(when distance between A and B is 10
km) A’s speed will be equal to B’s speed
and A and B will have a constant distance
between them. But as per our objective A
cannot be along with B.This constant
distance between them is offset.
![Page 55: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/55.jpg)
INTEGRAL ACTION
Now consider driver of A is a integral
controller.Here, after each km the driver of
car A senses the distance between A and B
and increases its speed accordingly.As it
approaches B, A slows down its speed and
when along with B, A drives in a constant
speed.
![Page 56: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/56.jpg)
Consider A is a derivative controller.Assume
A and B are together.When B accelerates his
speed A senses the rate of change of B’s
speed by sensing the rate of change of
distance between A and B.A accelerates its
speed in proportion to the rate of change of
distance between them.
Thus, combination of proportional + integral
+ derivative action shall keep cars A and B
together.
DERIVATIVE ACTION
![Page 57: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/57.jpg)
GAIN (P)
KC
X+_INPUT
SET PT
e (t)
TI
(A/B)
B
X
INTEGRATOR
SCALE 100 COUNTS / SEC INPUT – 100 – 0 - +100
DEAD TIME 1 SEC +_
X
to
KC
XDERIVATIVE TIME TD
IN SECS. CONSTANT
d (e) dt
I
+OUTPUT
CD (CONTROLLER’S B, AS SIGNAL
D
INTEGRAL TIME CONST IN SECS
A
KC. e(t) PROP. OUTPUT (P)
![Page 58: Boiler Turbine Control Basis](https://reader035.fdocuments.in/reader035/viewer/2022081502/55634be4d8b42a3a0d8b513b/html5/thumbnails/58.jpg)