Coal Gasification

उत्पाद विवरण

Coal Gasifier Working Principle and Plant Operation

A Coal Gasifier Plant is a thermal conversion system that converts solid coal into combustible producer gas through a process called gasification. This gas is commonly used as a fuel for kilns, furnaces, dryers, boilers, and other industrial heating applications. The gas produced mainly consists of carbon monoxide (CO), hydrogen (H), methane (CH), carbon dioxide (CO), and nitrogen (N).

1. Working Principle of Coal Gasifier

The coal gasification process takes place by partial combustion of coal in a limited supply of air or oxygen at high temperatures (typically 9001200C). Instead of complete combustion, coal reacts with air and steam to produce combustible gas.

Main Chemical Reactions

1. Combustion Reaction

   C + O CO + Heat

2. Reduction Reaction

   CO + C 2CO

3. Water Gas Reaction

   C + HO CO + H

4. Methanation Reaction

   C + 2H CH

These reactions generate producer gas, which can then be used as a fuel for heating processes.

2. Major Components of a Coal Gasifier Plant

A typical coal gasifier system consists of the following equipment:

1. Coal Feeding System
   • Coal is fed into the gasifier through a hopper or automatic feeder.
   • Required coal size is usually 2080 mm.
2. Gasification Reactor (Gasifier Vessel)
   • The main chamber where coal reacts with air and steam.
   • Lined with refractory material to withstand high temperatures.
3. Air Supply System
   • A blower supplies controlled air for partial combustion.
4. Ash Removal System
   • Ash generated during gasification is removed through a bottom ash discharge system.
5. Gas Cooling System
   • Hot gas is cooled using heat exchangers or water scrubbers.
6. Gas Cleaning System
   • Dust and tar are removed using cyclones, scrubbers, and filters.
7. Gas Distribution System
   • Clean producer gas is transported through pipelines to the end-use equipment.

3. Operation of Coal Gasifier Plant

Step 1 Coal Feeding

Sized coal is loaded into the coal hopper and gradually fed into the gasifier reactor.

Step 2 Ignition

The coal bed is ignited using diesel burners or electric igniters to start the gasification process.

Step 3 Gasification Process

Air is introduced through air nozzles at the bottom of the reactor. The coal reacts with air and steam at high temperatures, producing combustible producer gas.

Step 4 Gas Cooling and Cleaning

The produced gas passes through:

• Cyclone separators (remove dust)
• Gas scrubbers (remove tar and impurities)
• Cooling towers or heat exchangers

This ensures the gas is clean and suitable for industrial use.

Step 5 Gas Utilization

The cleaned gas is supplied to kilns, furnaces, boilers, or dryers as a fuel source.

Step 6 Ash Removal

Solid ash residues accumulate at the bottom and are periodically removed.

4. Types of Coal Gasifiers

Common types of coal gasifiers include:

1. Fixed Bed Gasifier (Updraft / Downdraft)
2. Fluidized Bed Gasifier
3. Entrained Flow Gasifier

Most industrial plants for ceramic kilns, sponge iron, and thermal processes use fixed bed coal gasifiers.

5. Advantages of Coal Gasifier Plant

• Lower fuel cost compared to oil or LPG
• High thermal efficiency
• Continuous fuel supply
• Suitable for high temperature industrial processes
• Reduced dependency on liquid fuels

6. Typical Operating Parameters