EMC: Use of 10 m Filter Bags Tested and Verified

In new plant concepts, exhaust gases from the clinker cooler and kiln are fed to the same filter in order to exploit synergy effects or to increase the amount of available heat when using extremely damp raw materials. Because of this trend to so-called “common filters”, dedusting plants are required for volume flows of 2,000,000 Am³/h and more.

In order to meet these requirements, Scheuch launched an internal R&D project aimed at further optimizing the technical concept for large-scale EMC filters with respect to cleaning and airflow and at verifying the use of filter bags with lengths of 10 meters.

The R&D Project
To verify the functionality and assess the maximum limits of EMC technology when using 10-meter long filter bags in grinding plants and kiln dedusting systems in the cement industry, long-term tests were performed using a full-scale EMC pilot plant. The goal of the project was to verify operational reliability as well as performance and design data during extended testing under realistic operating conditions.

Flow regulation in the filter casing was optimized by redesigning intake and discharge geometries, as well as guide and distribution devices, in order to guarantee the familiar low filter differential pressures for filter bags that also have lengths of 10 meters.

Comprehensive long-term tests were performed for cement grinding plants and kiln dedusting systems using representative dust types and filter media in order to determine the required design data for adequate operational safety and reliability when using 10-meter long filter bags. Comparative measurement series using different bag lengths confirmed virtually identical filtration performance for different bag lengths. The results clearly showed that the well-known advantages of EMC technology remain in full effect when using 10-meter long filter bags.

Advantages of 10-Meter Filter Bags
Especially noteworthy is the compact design associated with the use of 10-meter filter bags, as shown below in the table comparing key filter data for a volume flow of 1,000,000 Am3/h. In terms of the space required, savings of between 30 and 50 % could be realized, which it turn positively impacts the secondary investment costs for structural steel, substructures and foundation work.
 

In filters equipped with 10-meter bags, the proportions of length to width to height are also more flow-optimized and assure a better distribution of dust across the overall length in comparison to filters using shorter bags.

The use of EMC 10 m is already of interest starting at volume flows of 500,000 Am3/h and can cover a range of up to 3,000,000 Am3/h.

Existing filters systems equipped with 6-meter or 8-meter bags can be converted and expanded with the help of the 10-meter EMC technology. This is especially interesting for installations with limited space, where extending the overall length of the filtration plant is no longer possible.

The EMC 10-meter filter series also opens up new perspectives with respect to the conversion of electrostatic precipitators. The casing heights of 10 meters and more found in these ESPs can be used much more effectively, making it possible to realize larger filter surface areas and volume flows.