technical NOTES

Non-Woven Bags with appropriate finish for Coal & Cement Mill Product Collection Bag Houses

S. N. Head UOM Requirement for

Coal Mill

Requirement for

Cement Mill

4 Stitching Thread

Quality

NA Rastex / Equivalent Rastex/Equivalent

5 Vertical Stitch Lines No of rows 3 Min. 3 Min.

6 Overlap dimension MM Supplier to confirm

(minimum)

Supplier to

confirm (minimum)

7 Centre Wear Strip Reqd / Not

Reqd

Required for split

cage only - 1 No

Required for split

cage only - 1 No

8 Snap Band (SS 301

Spring Steel)

Reqd / Not

Reqd

Required - 1 No Required - 1 No

C Performance & Guarantee

1 Final Emission Ca-

pability

Less than < 10 Mg / Nm3 < 10 Mg / Nm3

2 Performance Guar-

antees (Life of Bag) Un- Condi-

3 Condition of Guar- tional 3-4 Years 3-4 Years

antees (Life of Bag)

5.9 Conclusion

• Raw Mill Bag House
  It can be seen from the above analysis that though good quality PTFE
  membrane filter bags have high capital cost but have low operating cost
  and low emission rate and also by keeping the same air to cloth ratio as
  that of conventional bags, the increased output at any time can be taken
  care of since it has some extra margin. Hence it is preferred to go in for
  PTFE membrane filter bag in RABH.

Since the cement mill bag house is a product dust collector and mill
capacity largely depends upon the efficiency of the filter, it is recommended
to use PTFE membrane filter bags in cement mill bag house also which
has less and consistent pressure drop. Also by keeping the same air to
cloth ratio as that of conventional bags, the increased output at any time
can be taken care of since it has some extra margin.

In India, the present accepted emission level as per PCB is less than
30mg/Nm3 which is easily achieved in Revere Air Bag House. In European
and American countries, the norms are very stringent i.e. less than 5-10
mg/Nm3, hence Pulse Jet Bag House is always preferred in spite of higher
operating cost.