Fans Blowers Final

8/13/2019 Fans Blowers Final

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Confederation of Indian Industry

FANS & BLOWERS


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FANS & BLOWERS

Machines to move gases/ gases mixedwith small solid particles

Centrifugalfans

Axial flow fans

Operation of fan similar to that of pumps

Efficiency offans (40-70%)


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Fans & Blowers - Major EnergyConsumer

CementPaperPower PlantsSugar

Energy Consumption - 10 to 25%- Depending on Type of Industry

Substantial Energy Saving Potential -Installing VSDs

Upto 25%


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PUMPS/BLOWERS FORMULAE

Rpm Capacity

Head Rpm2

Power Capacity x head

Power Rpm3


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If rpm is reduced what happens to

Capacity

Head

Power

PUMPS/BLOWERS FORMULAE


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Types of Control

Damper - Most Popular Variable Speed Drive

Recirculation

Damper

VFC

VFD

Ideal

Power

Flow25 7550 100

100

75

50

25


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FANS HOROSCOPECHARACTERISTIC CURVE

n1 rpm

n2 rpmPower consumption

80%

76%74%

Volumetric flow

P


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FAN EFFICIENCY

Q x P

102 x (m) x kW(I)

- Pressure rise of the fan, mm WC

(m) - Motor efficiency

Q-Volume flow rate in m3/s

P

kW(I) - Motor Input Power


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FACTORS AFFECTING THEPERFORMANCE OF A FAN

RPMDiameter

Density

Temperature

Parameter Rpm Diameter Density Temperature

Volumetric n D3 - -capacity

Pressure rise n2 D2 r 1/TPowerconsumption n3 D5 r 1/T


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THROTTLING OF A FAN

Suction/Delivery

Why?


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THROTTLING - SUCTION

0 mm

-600 mm

-700 mm

Average pressure of fan =(10336 - 700) + 10336

2= 9986 mmWg


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THROTTLING - DISCHARGE+100

(120) mm

-600 mm

0 mm

Average pressure of fan =

(10336 - 600) + (10336 + 100)

2= 10086 mmWg

Average density higherpower consumption high


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POWER CONSUMPTION OF ANOVER SIZED FAN

Fan designed1,20,000 m3/hr

650 mmWg

Actual requirement 90,000 m3/hr

510 mmWg

10 mmWg

Damper 60%

-500 mmWg-720 mmWg


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Consumes - 289 kW

POWER CONSUMPTION OF A OVERSIZED FAN

Power 730 mm Wg x 90000 m3/hr

Pressure rise = 10 - (-720)= 730 mmWg


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CORRECT SIZE FAN

+ 10 mmWg

-500 mm Wg

Pressure rise = 10 - (-500)

= 510 mmWg

Power 510 mmWg x 90000 m3/hr

Consumes - 202 kW


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Energy Loss in Damper Control..

Pr

essure

Volume

N1 rpm

N2 rpm

Loss Across Damper

Required

720

510


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POTENTIAL IN OVER SIZE FAN

Energy saving potential in over sized fan

= x Power consumption

= x 289 kW = 87 kW

P across damper

Total pressure rise

220

730


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ENERGY AUDIT IN FANS &BLOWERS

Is it off the correct capacity/head?

Is the fan/blower really required?

How is the fan controlled?

Damper throttling

Guide vane control

Speed control

ENERGY AUDIT IN FANS &


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ENERGY AUDIT IN FANS &BLOWERS

Replacement by high hfan

What is the efficiency of fan?

Can the capacity/head be further finetuned?

Can the blower be interlocked with

process operation?


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Coal Mill Ventilation Fan SpeedReduction

+ 5 mm

50%

BF

-360 mm

-270 mm

38 kW

Pressure drop = 90/365 = 24%Head required = 0.76 times present head

rpm of ventilationfan reduced by10%

Savings Rs 1.34 lakhs

Investment Rs 5000

Payback 1 month

Belt driven


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INSTALL A LOWER RPM MOTORFOR VENTILATION FAN

+ 20 mmWg

-150 mmWg-50 mmWg

38 kW

+ 50 mmWg

Pressure rise of the fan = 200 mmWgNet p across damper = 65%

P 130 mm wg


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INSTALL A LOWER RPM MOTORFOR VENTILATION FAN (contd)

Power consumption by 75 kW/ 980 rpmmotor = 50 kW

Replace with 75 kW/980 rpm motor

Power consumed by the 150 kW/ 1440 rpmmotor = 100 kW

savings - Rs.8.00 lakhsInvestment Rs 2.00 lakhs

Payback 3 months


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Install right size fan for ESP

Fan Design 1, 10, 000 m3/ hr, 200 mm

Variable speed

Plant originally rated for 300 TPD, operating

at 450 TPD

Present operation

1, 48, 000 m3/ hr, 110 mm WC

110 kW


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110 148Quantity km3/hr

200

Head

(MM)110

CHARACTERISTIC CURVE

Des point -Eff. - 78 %

Op point

Eff. - 44 %

1000 rpm

740 rpm


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Install right size fan for ESP

Install right size fan

Capacity - 1, 50, 000 m3/ hr

Pressure - 125 mm

Annual Savings - Rs. 12.00 Lakhs

Investment - Rs. 10.0 Lakhs

Payback - 10 Months


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INSTALL HIGH EFFICIENCY FANFOR COOLER FAN #1

80%

Temperature32oC

Temperature55oC

550 mmWg

Fan inefficient = 54%Replaced with

high efficiency fan

Savings Rs 3.00 lakhs

Investment Rs 4.00 lakhs

Payback 16 months


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Install VFD for Boiler ID Fans

Present ControlDamper Based on Furnace DraughtEnergy Loss Across Damper

-60mm -110mm

50% ID Fan53kW

VFD-29kW

30TPH

Boiler

ESP VFD

PIC


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Install VFD for Boiler ID Fans..

Install Variable Frequency Drive (VFD)Control by Varying SpeedDamper - 100% Open

Power with damper = 53 kWPower with VFD = 29 kW

Savings = 24 kW

Annual Savings - Rs. 7.76 LakhsInvestment - Rs. 6.85 Lakhs

Payback - 11 Months


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Confederation of Indian Industry Confederation of Indian Industry

ID Fans Operation

ESP

ID Fan

ID fan is operated with fluid coupling & IGVControl

System studied in detail

135 m3

/sec, 236 mmWg, 645 KW Overall efficiency52%

Where to attack?


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ID Fans Operation

ID fans power consumption

Motor losses, VFC and fanThese need to be looked into

Motor VFC FanInput Power

100%

645 kW

Fluid Power52%333 kW

hLoss6%

38.7 kW

hLoss20.46%129 kW

hLoss21.54 %144 kW


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ID Fans Operation

Loss in Variable fluid Coupling


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% loss is highest at 66% speed For this fluid coupling few suppliers

Loss estimated at 132 KW

Calculated loss also 127 KW

How to Avoid / Reduce this?

Replace VFC with high efficient VSD

Operate VFC with higher speed

not possible

ID Fans Operation


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Based on ID fan characteristic curve

Reduction in speed

Doesnt affect operating

efficiency much

ID Fans Operation


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How to proceed now?I Step

Reduce IGV Control and lower speed of fan &control through VFC

Explore the option of putting VFC in closed

loop with draught

Discuss with suppliers & collect loss curves

At 40% speedclosed loop should be

possible

Replace with quick response actuator Operating in many cement plants for critical

fan applications

Soda recovery boilers in paper plant

ID Fans Operation


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How to proceed now?II Step

Replace VFC with a 6.6 KV VFD

Excellent long term option

HT VFDs installed already

Chettinad cement6 drives- recently

Tata powerVFD for ID fan

Operating for last 8 years

ChinaRecent years several HT VFDs

installed

ID Fans Operation


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ID Fans Operation

Option -1

Annual Saving - Rs 30.2 Lakhs

Option -2

Annual Saving - Rs 198 Lakhs

Investment - Rs 375 Lakhs

Payback period - 23 Months


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To Sum Up

Fans & Blowers -Energy Savings

Industry

Implement

Benefit


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C f d ti f I di I d t

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Fans Blowers Final

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