The Application Of WIN-9PF High Power Inverter In The Circulating Fluidized Bed Boiler


The Application of WIN-9PF High Power Inverter in the Circulating Fluidized Bed Boiler

Abstract:

This essay explains the successful application of WIN-9PF high power inverter in the circulating fluidized bed boiler in a power plant owned by Guizhou Weng’an coal mine.

Key words

WIN-9PF high power inverter, circulating fluidized bed boiler, energy saving

1.Foreword

Although most circulating fluidized bed boilers in china have installed high-efficient centrifugal fans, yet energy saving efficiency is still under satisfaction, due to the fans’ low speed control performance. If reconstructing this fan with a high power inverter, so as to adjust the wind volume according to different production requirements through controlling the motor speed, it can save a mass of energy. After careful investigation, Guizhou Weng’an coal mine bought three sets of WIN-9PF high power inverters from Shenzhen Winner S&T Co, with an aim to enhance the production reliability of its circulating fluidized bed boiler.

2.System design

The 35T/h circulating fluidized bed boiler in the power plant of Weng’an coal mine has a 280kW fan blower (primary air fan), a 110 kW secondary air fan and a 355kW induced draft fan. This system puts forward exactly high requirements to the speed control system as any of the three fans breaks down, the circulating fluidized bed boiler will stop working. To achieve proper reliability, all of the three inverters have added the manual bypass function, which enables the fan can be switched to mains supply if the inverter has fault.

3.Field operation

After reconstruction, the 35T/h circulating fluidized bed boiler shows many prominent advantages as mentioned below:

  1. Improved starting performance, less pollution to the grid;
  2. WIN-9PF inverter can help dramatically reduce mechanic vibration, noise and mechanic wear, so as to enhance system reliability and prolong the service life of the devices.
  3. More convenient operation. The user can realize exact wind volume and wind pressure adjustment through WIN-9PF inverters, which can save a large quantity of power.

Main features of WIN-9PF series inverter:

  1. The energy saving operation mode can be preset
  2. As many as 28 protection functions and fault alarm functions
  3. Built-in PID regulator
  4. parameter online monitoring function and online regulating function
  5. SPWM technology control
  6. Rated torque output at low speed
  7. Fast acclimatization to load change, capable of providing high efficient output voltage
  8. Built-in RS-485 communication port that accords with MODBUS protocol.
  9. Advanced automatic torque compensation function, optimizing the performance of the inverter

4.Energy saving analysis

Please refer to the following table:

 

Compared Item

Mark

Unit

Data Source

Value

Mains Supply

Inverter

1

Testing time

T1

Min

Measured

60

60

2

Atmospheric pressure

PB

Pa

Measured

101500

101500

3

Ambient temperature

t

Measured

28.1

23.4

4

Motor speed

R

r/min

Measured

996

472

5

Pitot tube factor

K

 

Standard value

1

1

6

Gas temp. of cross section

ty

Measured

108

101

7

cross section static pressure

Pa

Pa

Measured

48.7

33.5

8

Root-mean-square cross-section dynamic pressure

Hd

Pa

 

13.14

13.14

9

Gas in standard state

γ0

N/Nm3

According to the meter

9.9457

10.1522

10

Gas in the cross section

γ

N/Nm3

 

9.8016

10.1522

11

Wind speed at the cross section

υ

m/s

 

9.8016

8.0462

12

induced wind volume per hour

qr

m3/h

V x F x 3600

216478

177709

13

Average voltage

U

V

Measured

394

212

14

Average current

I

A

Measured

74.85

15.10

15

Power factor

cosφ

Measured

0.637

0.989

16

apparent power

s

kVA

Measured

550.31

95.88

17

reactive power

q

kvar

Measured

424.41

14.35

18

active power

ω

kW

Measured

350.55

94.80

19

Input reactive energy

ωq

kvar.h

Measured

424.41

14.35

20

Input active energy

ωp

kWh

Measured

350.55

94.8

21

main frequency

f

Hz

Measured

50.01

23.55

22

Opening of air throttle

Fm

%

Measured

24.7

100

23

power consumed by every ten thousand cube meters induced wind volume

Pd

kW.h/Nm3

Wp / qf

16.1932

5.3346

After reconstruction, the energy saving rate of the induced draft fan is:

(power consumed at mains frequency kW.h/Nm3— power consumed at converted frequencykW.h/Nm3)/power consumed at mains frequencykW.h/Nm3=16.1932 - 5.3346/ 16.1932 x 100%= 67.06%

5.Potential problem and solutions

  1. As the fan blower and the induced draft fan are both of large inertia load, DC overvoltage fault at deceleration is inclined to occur. So the braking unit or braking resistor should be added here. Only by increasing the acceleration/deceleration time to 300-350s, and inputting DC control voltage on the motor at start and stop, this fault can be removed.
  2. As the fan blower and the induced draft fan are both of high power load, overheating fault is inclined to occur in summer. Please install the cooling fans or other air conditioning devices in the control cabinet to prevent the temperature from overheating.

Reference:

"WIN-HV operation instruction"