64 / 140
As expected, the 3 year old membrane filters from filter
bag supplier 1 were operating with the highest filter drag.
The brand new standard drag membrane filters performed
significantly better, but the brand new GORE LOW DRAG
filter bags displayed the lowest filter drag.
Data analysis
With the data acquisition frequency set for 10 sec. intervals,
a huge data set was developed over the course of the trial.
As shown in Figure 5, the existing membrane filter bags had
the highest filter drag, trended upward, and maintained
the highest filter drag over the entire time period. The
brand new standard drag filter bags from Supplier 1 and
Supplier 2 also both trended upward over the 9.5-month
timeframe. Meanwhile, the brand new GORE LOW DRAG
filter bags maintained a relatively flat filter drag.
During the plant’s 2018 winter shutdown, the
compartments were inspected visually from the clean side.
The inspection of module 9, with the GORE LOW DRAG
filter bags installed, revealed the compartment was free of
dust (Figure 6).
Conclusion
Eight months into the trial, the GORE LOW DRAG filter
bags were operating with a 22% and 25% lower filter drag
than the 8 month old standard drag membrane filters and
48% lower than the 3 year, 8 month old standard filter
drag filters. Given the filter drag trends observed during
the demonstration, along with the membrane properties of
all of the filters, it is expected the filter drag differences will
continue to improve over time.
Based on the 1.513 million acm/hr the baghouse fan
is moving, the data suggests there would be a significant
reduction in fan energy requirements through the use of
the GORE LOW DRAG filter bags. The 48% reduction in
filter drag would allow the inlet static pressure of the fan
to be reduced by 2.5 in. water gauge, while maintaining
the current airflow. This would create an annual saving
of US$174 000, based on the plant’s current average
electricity costs, thanks to the reduction in fan static
pressure. In addition, the lifetime of the GORE LOW
DRAG filter bags is expected to be significantly longer
because they do not experience the same seasoning
effect as the standard membrane filter bags. Longer
lifetime and reduced operating costs equate to an
impressive reduction in TCO, proving the value of such an
investment.
Acknowledgment
The author gratefully acknowledges Jeannette Williams and Louis
Raath for their work on the original version of this document.
References
1. POLIZZI, C., ‘Knowing your TCO’,
World Cement
, Vol. 49,
No. 2 (February 2018), pp. 45 – 49.
About the author
Chris Polizzi is Senior Cement Specialist at W.L. Gore & Associates.