239 posts
TimePosted 18/09/2009 07:34:16
xxxx says

coal bag filter dp

after checking &  doing everything with respet to reduction of DP of my coal mill filter i am unable to reduce the DP.

with new bags it runs for 20-25 days only & than Dp touches 150mmwg & coal mill production reduces.

I have 6ksc dry air pressure, high purging frequency,no jamming,no pipes loose or worn out,periodic drain of moisture, low air to cloth ratioo (~ 1).

Before bag filter i have a collecting cyclone.


to increase air amount in the system i have shortened the dip tube by 300mm . now the dip tube is just 80-90mm below the inlet entry height.

when we replace some bags by new one we get a relief on temporary basis but agter some days the position is same.

please suggest.

Coal residue is 4 to 6 % on 72 mesh

we sre grinding petrocoke + indian coal (80+20% mix.)

we have close circuit ball mill of  FLS  

 please do suggest.





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Michael Clark
324 posts
TimePosted 01/10/2009 15:41:32

Re: coal bag filter dp

It is very difficult to suggest a remedy for this problem. It might be connected with intergrinding the petcoke and coal. In that situation I would expect the coal to be significantly overgorund.


77 posts
TimePosted 01/10/2009 18:09:03
Vikpro says

Re: coal bag filter dp

Mr. Rajesh,
I feel that your BF DP problem may be due to high raw coal moisture. once you try with some dry coal. inform us about peak summer operation condition also.


44 posts
TimePosted 02/10/2009 04:44:00
hongminh says

Re: coal bag filter dp

i agreed with opinions of Mr Vikpro and i have a advise for you that following:

- checking the water content in air compressor.

- change the new mesh size of 88 or 90 and reduce coal residue of 4 to 6% if possible.

- checking coal moisture feeded to the mill.

- checking and make a new setting  for air pulse to rapping coal dust on the surface of sleeves.

- air pressure enough?


best regard.