Pneumatic Conveying may be understand as conveying the solids of any kind of material like cement particles, Limestone powder, Fly Ash Particles, Gypsum, or any non diluted solid particle with some bulk density above 25 Kg/M3 from one place to an other place through pipe lines by flowing certain amount of Air Pressure depending upon the Bulk Density of Particles. With Pneumatic Conveying Technology material can be transported from a hopper or any other originated medium upto silo or any other destination located at a considerable distance through a totally closed automated system.
There is minimum possibility of dust generation to the open atmosphere resulting to convey any hazardous material. Through totally enclosed system wide range to material can be transported to any designated location in powder or granular form. A widely used example of Pneumatic Conveying System is Pneumatic Ash Handling system in which Ash (waste burnt material generated from firing of fuel like Bagasse, Coal or Rice Husk) is being conveyed from Boiler outlet point to a silo without touching the material and safely unloaded to a vehicle for disposal as the burning temperature of the material is very high and very difficult to convey through traditional ways like screw conveyor or any other system open to atmosphere as it generates lots of dust and unhygienic for human body. In pneumatic conveying system material is being conveyed through various pipelines laid vertically or horizontally and the flow of material can be controlled through automated systems controlled through Microprocessor based PLC.
In Pneumatic conveying material can be conveyed by to ways of flow :-
Dilute Phase:- Any material can be conveyed in dilute phase conveying irrespective of any size or density of the particle. In dilute phase conveying velocity of particle to be conveyed should be very high resulting to very high consumption of power. Also in case of dilute phase conveying the particle flows in close contact with the pipeline walls and there are very high chances of erosion of pipelines and bend walls.
Semi-Dense Phase :- Material conveying is the optimum solution for medium rate transfer of aeratable abrasive materials. It requires higher positive air pressure for conveying the material over long distance at medium velocity.
Dense Phase Conveying :-In dense phase conveying mode material can be transported :-
- One way of conveying of material is moving bed flow in which material is conveyed in bank on the bottom of the conveying lines.
- Another way of conveying of material in dense phase is Plug type flow in which the material is separated by flow of air.
- It requires low installation cost with higher reliability & low maintenance cost.