Air Pollution Control Device For Induction Furnace - India

Air Pollution Control System for Induction Furnace (Steel)

About Induction Melting Furnace

Induction Melting Furnace is major steel producing technology using scrap & sponge iron (Directly Reduced Iron) as main raw material.

This technology contributes significant steel making capacity in secondary steel sector in India.

It has some distinct advantages:

Low Project Capital Cost

Low Energy Cost

Consumes steel scrap which is a major solid waste

Environment Friendly, as it produces lower emission than Primary Blast Furnace

Uses clean fuel i.e. electrical power

Can be set up near source which saves transportation cost of raw material as well as finished goods

Manufacturing Process

Induction Furnace Process includes melting of various types of steel scrap in a pot.

The energy required for the melting process is provided by electrical induction furnace.

The feeding of raw material in the induction furnace is on intermittent basis.

As one charge of scrap melts, slag is removed from the molten metal and certain alloys are added to achieve the desired grade of steel.

Molten metal is then poured in to refractory lined buckets from where it is further poured in different sizes moulds to get the desired size of steel.

Ingot/Billet is allowed to cool down and then the product is separated from the moulds.

Flue gases are generated during melting of scrap.

The characteristics and volume of these gases mainly depends upon type of scrap used in the furnace, i.e. with the degree of contamination in the Scrap.

These flue gases need proper treatment for removal of dust particles/gases before being discharged into the atmosphere.

Air Pollution

Steel scrap which comes from various sources and generally has contamination/coating etc on it.

When this scrap is heated contamination/coating etc disintegrates from steel and comes out either as slag or becomes air borne, thus causing air pollution.

The major source of Air Pollution is:

Dust & Dirt

Rust

Oil & Grease Paint

Galvanized Iron

PVC Coated Steel

Capacity Calculation of Required Equipment

The volumetric capacity of Air Pollution cannot be judged as such but fair engineering estimation can be made with input data like:

Furnace Capacity

Power Rating in KWH

Detail Drawing of Furnace

Air Cooler Arrangement for workers at Furnace Platform

Characteristics of Air Pollution Generated In Induction Furnace

Pollutant : Dust & Dirt, Metal Oxide & Traces of NOx, SO2, CO, CO2

Concentration : Average 600-800 mg/Nm3 Max.

1200-1400 mg/Nm3

Temperature : At Hood: 250-300o C At Bag House: 80-120 o C

Nature of Dust : Non Sticky, Non Abrasive and Non Explosive

Control Practices

The Control Practice adopted in controlling air pollution in this industry mainly depends upon following parameters:

Dust/Gas Concentration at Inlet

Discharge Standards

Temperature of Flue Gases

Nature of Pollutant i.e. Dust or Gaseous

Nature of Dust i.e. Sticky, Abrasive

Nature of Gases i.e. Corrosive, Non Corrosive

Selection of Technology for Equipssment

The Following technologies are usually adopted for Air Pollution Control System in Induction Furnace industry:

a.

Bag Filter Type System (Dry)

b.

Venturi Scrubber Type System (Wet)

About Bag Filter Type System (Dry Process)

Working of Equipment Bag Filter Type System

Suction Hood: Feeding of raw material is an intermittent process in Induction Furnace and at the time of completion of every heat, molten metal is tapped with tilting platform of furnace.

Hence, it requires a Movable Hood System so as to facilitate slag removal, raw material (bulk) feeding and tilting of platform.

Hoods are designed based on crucible diameter and optimum clearance of hood from furnace.

Ducts & Bends: Ducts and Bends are required to convey flue gases from point of suction to the chimney and connect various equipments like Hood, Spark Arrestor, Bag House, ID Fan and Chimney.

Their sizes are based on flue gases volume & temperature.

Spark Arrestor: It is used for arresting live particles and large hot particles which can damage & burn bags.

It also facilitates in settling of large dust particles and works as a pre-cleaner.

Its size depends upon gas volume and unit layout.

Bag Filtration System: It is used for fine filtration of Flue gases to remove dust particulate matter.

The dust is retained on one side of Bag and clean gases are received on other side.

The combined treated gases from all the bags are collected at top of bag house and are passed through to ID Fan.

The dust collected on other side of bags is de-dusted through pulse air jet mechanism with high pressure air.

The dust is collected at bottom of hopper and is discharged through Rotary Air Lock Valve.

Pulse jet mechanism is carried out through high pressure air with the help of sequencer and solenoid valve.

Id Fan: ID Fan provides necessary driving force to convey flue gases from suction hood to top of the chimney.

The volume sucked overcomes the total resistance offered by equipment and duct with the help of fluid horse power provided by ID Fan driven by suitable motor.

Stack (Chimney): The generated gases are passed through chimney of suitable height and diameter.

The chimneys are provided and based on volume of flue gases temperature, dispersion desired, composition of gases and legal provisions for height.

Advantages & Disadvantages of Bag Filter Type System

Advantages:

Low Power Consumption

Dry System, No water pollution

No corrosion of metal except normal wear & tear

Suitable for dust pollution which are the major cause of pollution in induction furnace

Achieves desired characteristic of treated gases even for high dust load, as efficiency of bag filters is very high

Low operation & maintenance cost

Dry system, hence high life cycle of plant

Disadvantages:

Large Floor Area

With Spark or live particle, bags can burn

Working of Equipment Venturi Scrubber Type System

Venturi Scrubber: In Venturi Scrubber the flue gases are passed through a converging section where velocity of the gases becomes very high.

The water is sprayed on high velocity gases with high pressure at throat.

The particles in the gases become wet.

The purpose of throat is to provide the area with highest velocity and wet these particles so that they become heavy and easily removable.

The gases are then passed through a diverging section where lot of energy is recovered which was lost in converging section.

These gases are then passed through separator where wet dust particles are collected at bottom and clean gases are passed through mist eliminator followed by exit from scrubber.

Advantages & Disadvantages of Venturi Scrubber Type System

Low Floor Area

Can handle high temperature gases

Suitable for gas pollution such as SO2, NOx etc.

High Power Consumption to achieve desired standards

Generates Water Pollution

Material of Construction is prone to corrosion hence low life cycle

Choking of pipe, Nozzle and duct (near scrubber) due to Wet condition

High operation & maintenance cost

Can remove submicron particle only with very high pressure drop leading to still high power consumption

Discharge Characteristics as Per Norms

Dust : Less than 150 mg/ Nm3

Temp: Less than 80-100 o C

Gases : Traces of SO2, NOx, CO2 CO

Suction Efficiency : More than 90%

Company Contact:

• Posted By: Eros Envirotech Pvt. Ltd.

• Phone: 911612542109

• Address: 109-110, Savitri Complex-1, Dada Motors Building, G.T.Road, India

• Email:

• Website: https://www.erosenvirotech.com

• Business Description: Eros Envirotech Pvt.
  
  Ltd. is one of the leading Manufacturer and
  
  Exporters of Lead Acid Battery Recycling Unit, Air and Water Pollution
  
  Control System, Pots for Refining and Alloying, Ball mills for Lead
  
  Oxide accepted all over worldwide.
  
  The company from last 2 decade is ISO
  
  9001: 2008 certified.