Gas collection, cleaning and cooling

Following collection, the gases may need cooling depending on the dust abatement system used. In the hot blast operation, the heat recovered from cooling may be used for preheating the blast air. 

Several options are possible for cooling the collected gases, including  

Using tube coolers Running the collected gases through long ducts, decreases the temperature by natural convection and radiation. This system is simple but takes up a lot of space and does not offer controlled cooling (therefore there is a risk of condensation) 

Using an oil/gas heat-exchanger This is similar to the above system but more expensive because of the need for a secondary cooling system. The heat-exchanger is generally cooled with a circulation of mineral oil. Cooling with a water/gas heat-exchanger is not (or only very rarely) practised 

Both venturi scrubbers and disintegrators are used with cupola systems. Descriptions of these systems are given in Section 4.5.1.3. A separator to remove small particles entrained in water droplets, is located after the wet scrubber. 

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