VFD for ID (Induced Draft) fan and FD (Forced Draft) Fan of Boiler.

Application overview

Boiler is a application where fuel (Oil, Gases, Coal, Etc) energy is converted into Steam energy. This steam energy is further used in power generation or other purposes in industry. There are different types of Boilers such as Water tube, Fire tube, Etc. They are selected as per size and application needs.

Basic Principle is to convert Water into steam by heating it. When water is heat above boiling temperature it gets converted in steam. But if we boil water in open atmosphere there would be lot of waste of energy.


So, Boiler is closed from all sides to save waste of energy. But when fuel is combust in closed place it will turn off when oxygen in chamber finishes. So Along with fuel we need to feed air into chamber to keep fuel burning and generate energy. This feeding is done by forced draft (FD) Fans.

After burning of fuel it generates wastes such as gases or ash. And to remove this you need a fan suck of this ash particles or gases out. Induced draft fans are used to do this.boiler-vfd-application-schematic-solims



Reason to use VFD in ID and FD Fans

When air is feed to combustion it should be in proportion to fuel feed to chamber and get maximum heat energy.  Same is in the case of ID fan Amount of waste gases and particle to be thrown out is depended on amount of fuel burnt and heat generated.


Here is an example Coal Boiler in this boiler you can see actual boiler, Coal feeder Screw conveyor, Coal feeder hopper,  Boiler vessel, FD fan Inlet. Steam outlet and ID fan Outlet.


This Fan application is Variable torque application. So when you drop down the frequency of either Fan as per the need you will get energy saving as per the Law of affinity.

Even in Water feeding  pump you can use VFD and Get energy saving.


Features Required in VFD.

  1. Overload capacity of 120% for 60 Secs ( Normal Duty)
  2. Potentiometer or Analog Input to Vary the speed Of Motor.
  3. Coast to stop Operation of High amount of deceleration time, because due to high inertia of Fan Motor might go into regeneration and back emf energy may trip VFD on Overvoltage.
  4. Standard V/F or Vector control
  5. Ambient Temperature 40 C (If at hotter location 50 c or use heavy Duty VFD)


Best Recommended Brands by Team Solims For ID and FD Fans

                Hitachi, Fuji, CG (Crompton greaves), Delta, and ABB


If you need any help related to VFD for ID fan or FD fan you can call us any time or you can feel free to write us at info@solims.com We will be pleasure to help you technically commercially etc with our expert team.



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