Dust In Steel Plant
1 - Dust larger than 100 micron are as bricks to a dust extraction plant. Baghouses work mainly with 50 micron and less. It you have larger particles it is better to instal a cyclone to take out the grit.
2 - If you have a lot of suction, and you are wearing out your ducts it means you are sucking in grit as well as dust.
3 - Grit is a nuisance, abrasive and dirty, but is not respirable - i.e. not readily taken in by the lungs. Respirable dust would be 10 micron or less.
4 - You certainly have a problem. It is difficult to summarise everything in one or two paragraphs. There are no easy fixes, but there are a number of things which could be done. I would recommend you call in a Dust Engineer to look at the set up. Alternatively the Technical Support Engineer from your Dust Extraction Equipment Vendor could advise. ■
Dedusting Of Fines Conveyor
From your description, I would expect that some duct velocities are too high because the airflows are unbalanced.
You need someone who understands the design of systems to measure airflows and analyse your problem.
If the system has been designed well, there should not be too much material entrained by the ducting. Hoods should not be placed so close to the material stream that large amounts of material (as opposed to dust) is entrained.
If the high velocities are the result of imbalance, re-balance the system. Balancing involves adjusting the blast gates (dampers) until all the velocities are equal, to within 5% or 10%.
There may be more to it than this. Have an expert look at the problem.
Michael Reid. ■
Dedusting System Of Fines Conveyor
Thanks to all,
System is operated not on bag filter but an ESP of ID fan capacity.
:400,000m3/hr whose main duct has 5 branches to a fine conveyor.
Can Cyclone be more efficient??
Generally velocity should be around 18-20m/s in the duct.
But do anybody has idea of duct velocity over fine conveyors????
1)Balancing is already being done by a hired party which was not technologically advanced and they do it by adjusting the dampers manually which is not effective and also time consuming.It took them 10 days.
What are advanced ways of flow balancing ?
2)What are the possibbility of Liners over the cross-section of ducts?along with there costs.What is its life.
If liners are been put up then can dust problems can be solved by fully covering the area i.e. deskboard sealing???
what are its demerits??
Any alternatives.....
Kind Regards,
Prakhar ■
Dedusting Systems In Fines Conveyor
Dedusting will not be effective if conveyor skirting is not well adjusted and transfers not properly enclosed. There will be excessive local emissions if these are not attended to.
Cyclones are not a solution.
Balancing must be done manually, there is no quick way. In a system of 400,000 m3/h, it is likely to take several days.
Ceramic linings in bends and vulnerable duct sections will improve duct life many times.
In your circumstances, try to keep velocity at 20 m/s but below 22 m/s.
Michael Reid. ■
Dedusting system of Fines conveyor
Dear friends,
I am working in a steel plant stock house.
Genuine problem for the labours is the DUST.
We have problem regarding dedusting of return fines conveyor.They are as follows:-
1)Ducts over this conveyor is originating from main duct so suction pressure is high.....but that results in extreme wear of duct surface as well as wear of chute ends.
2)Return fines are highly abrasive and extremely harmful for respiration.
I would welcome any kind of suggestions.
Thanks.
Prakhar Jha ■