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View challenge: C-7110-0102 - Seeking solutions to determine sinter bed permeability
The goal of sinter plant is to attain consistent chemical and physical properties by reducing sinter chemistry variation, improving the reaction index, the crushing strength. The process starts with the mixing of raw materials that is eventully fed to Blast Furnaces. This raw material mix is commonly referred to as "Sinter Materials". The primary challenge of a sinter plant is to attain the consistency in the chemical and physical properties of this material (i.e obtaining consistency in sinter chemistry), as this has a direct impact on the blast furnace efficiency.

The place where the raw material is mixed is called the raw material section. In this section raw materials such as iron ore (60-65% FeO), oxides like lime, alumina, magnesia, silica, fines of wastes like returned coke & sinter and mills scrap etc are mixed to form huge piles (heaps). The material from these piles is later on mixed with water in a mixing drum (blender/tumbler). Water is used only to create dampness in the mixture and not to create a slurry. This damp mixture is then laid on the input conveyor of sinter bed continuously. Typically the sinter bed is of the height of ~200-250 mm. It traverses with a speed of around 2-5m/sec and covers a distance of 30-60 meters depending upon the plant capacity.

Sintering of the raw material is initiated at the ignition hood that is located at the charging end of the bed. The sintering process is initiated by igniting the top layer of the bed.

As the bed traverses, the air and coke breeze mixture is blown onto the running bed from the top which is sucked from the bottom by a series of suction fans. Due to this phenomenon, the ignition remains alive and the flame front propagates diagonally downwards forming layers of sintered material (baked material) trailing behind. Typical temperatures in the sinter bed vary from 600 to 800 C.

The air flow rate crossing the raw mix characterizes the permeability of the bed. Permeability of the bed cake (damp mixture that is laid on the input conveyor) plays an important role as it helps the flame front to proceed uniformly. The desired physical and chemical properties of sinter is achieved by controlling the bed permeability.

Traditionally, the bed permeability is adjusted by adding water to the raw mix in the mixing drum. As the direct measurement of the bed permeability is not available, the control of the sinter making process is not optimal and the amount of water addition cannot be controlled accurately.

We are therefore, seeking solutions to determine sinter bed permeability.

Typically the solution would focus on -
1. measuring permeability early in the process (i.e the space immedilately after the raw mix is laid on the conveyor and before the raw material enters the ignition hood) so that correction becomes easier.

2. Automating water addition (in the mixing drum) to achieve the desired sinter bed permeability using a feedback mechanism.

3. With the use of Auto-Permeability Control System, the variation of Sinter chemistry must reduce.

Measures -
1. Low standard deviation of chemical and physical properties.
2. Enhance yield % and crushing strength.
Importance
Key Expectation from the solution
Must Meet
 Measuring permeability early in the process
Must Meet
 With the use of Auto-Permeability Control System, the variation of Sinter chemistry must reduce.
Must Meet
 
Good if Met
 
Good if Met
 
Good if Met
 
Challenge Start date: 09-Jan-17         
End date: 18-May-17
 Scheduled
 Completed
 In progress
 Need attention
RS 1,00,000 and business opportunities
 

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