Industrial Dust Collection
Blast Furnace Cast House Dust Collection System
Offline pulse baghouse with capture hoods on the cast house and slag runner, replacing an undersized collector that could not hold the emission limit during tapping.
Original condition
The problem on site
The existing collector was sized for a smaller furnace campaign. During tapping, dust escaped through the cast house roof, bag blinding raised resistance above 2,400 Pa and the fan could not hold the required negative pressure. The plant also faced a short shutdown window for the retrofit.
Engineering approach
What we designed and built
- 01Re-measured dust source points at the taphole, runner and slag pit, then redesigned capture hoods and duct routing to shorten the run and balance the pressure drop.
- 02Sized a new 8-chamber offline pulse baghouse at 6,400 m² filter area with cloth velocity below 1.0 m/min for abrasive cast house dust.
- 03Selected PTFE membrane filter bags with anti-static treatment and hardened hoppers to extend service life under abrasive load.
- 04Installed a VFD controlled induced draft fan with pressure feedback so the system follows the tapping cycle instead of running at fixed speed.
- 05Pre-assembled chambers in the factory and used a modular lifting plan to complete the installation inside the scheduled shutdown.
Measured results
Before and after commissioning
Values recorded on this project under its own operating condition. Results at another plant depend on fuel, material, load profile and the local standard in force.
| Item | Before | After |
|---|---|---|
| Handled air volume | 180,000 m³/h (insufficient capture) | 320,000 m³/h with new hood design |
| Outlet dust concentration | Above site limit during tapping | Stable low level, verified by site CEMS |
| System resistance | 2,400 Pa with blinded bags | 1,450 Pa after cleaning system upgrade |
| Bag life | About 8 months | Over 24 months with PTFE membrane media |
Outcome
How the system runs now
After commissioning, the cast house roof no longer shows visible emission during tapping, system resistance stays around 1,450 Pa and the fan runs at reduced speed for most of the cycle. Emission values are recorded by the plant CEMS and remain within the site limit, subject to local regulation and actual operating condition.
Site records
Fabrication, erection and commissioning
Planning a similar retrofit or new build?
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