Objective
Solaft was approached by a cement factory in Germany to find out what options they had to increase capacity aside from a new baghouse refit.

Issue
The factory’s baghouses had reached capacity and required an expensive refit to meet new output demands. There was a 25% planned increase in airflow and dust loading due to plant changes, and a high-pressure drop was unacceptable. A new baghouse refit was costed at 1m Euro.

Solution
Solaft’s technical team determined that Solaft ‘s trademarked StarBags™ would best suit the requirements. The increased surface of the StarBags™ in comparison to the incumbent filter bag and unique design allows from greater particulate capture, less pulsing and reduced flow required for similar production output. An onsite trial was then conducted.

Pre Upgrade filter operation:
• Operated with 1,860 Am3/min at 90°C and 933 mbar static press.
• This gave an A/C ratio of 1.57 m/min.
• Diff Press was controlled at 14.5 mbar.
• The dust load was ~2.7 g/Am3 (or 3.6 g/Nm3 or 300 kg/h).
• Bag cleaning header pressure for bag cleaning was 6 bar.
• Operated with a cleaning frequency of 3.3 cycles/hour (pulsing @ 11 sec).

Planned filter operation requirements post upgrade:
• Air flow = 2,312 m3/min during normal op. and 2,870 m3/min during upset.
• Gas temperature = 90°C.
• Dust concentrations remain the same.
• Dust emission target: 10 mg/Nm3.

Post installation filter operation:
• Diff Press 8mbar @ 110,000 Am3/h (A/C ~ 0.94m/min).
• Diff Press 4mbar @ 90,000 Am3/h (A/C ~ 0.77m/min).
• Dust emissions achieved <10mg/Nm3.
• Filter inlet temp. ~80-85°C.

Outcome
After the successful trial, the Cement company benefits were:
• Air-to-Cloth ratio decreased.
• Emissions decreased and within target range.
• Cleaning with Pulse air dramatically reduced – impact as pulsing of bags is direct proportional to life of bags.
• Energy saved by less pulsing and less fan amps as compared to standard operation cement plant dock-up cooler baghouse delivering value.
• Capital expenditure savings with no need for a new baghouse with 25% increased airflow. A €65k outlay versus €1m.