Applications > 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

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:

Improved starting performance, less pollution to the grid;
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.
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:

The energy saving operation mode can be preset
As many as 28 protection functions and fault alarm functions
Built-in PID regulator
parameter online monitoring function and online regulating function
SPWM technology control
Rated torque output at low speed
Fast acclimatization to load change, capable of providing high efficient output voltage
Built-in RS-485 communication port that accords with MODBUS protocol.
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
	Compared Item	Mark	Unit	Data Source	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 frequency（kW.h/Nm3）)/power consumed at mains frequency（kW.h/Nm3）=（16.1932 - 5.3346）/ 16.1932 x 100%= 67.06%

5.Potential problem and solutions

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.
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.