Filter tests clean pressure drop test

Pressure drop, initial The pressure drop obtained on a test on a clean filter. 

The objective of the present study is to develop a cross-flow filtration module operated under low transmembrane pressure drop that can result in high permeate flux, and also to demonstrate the efficient use of such a module to continuously separate wax from ultrafine iron catalyst particles from simulated FTS catalyst/ wax slurry products from an SBCR pilot plant unit. An important goal of this research was to monitor and record cross-flow flux measurements over a longterm time-on-stream (TOS) period (500+ h). Two types (active and passive) of permeate flux maintenance procedures were developed and tested during this study. Depending on the efficiency of different flux maintenance or filter media cleaning procedures employed over the long-term test to stabilize the flux over time, the most efficient procedure can be selected for further development and cost optimization. The effect of mono-olefins and aliphatic alcohols on permeate flux and on the efficiency of the filter membrane for catalyst/wax separation was also studied. 

United Power Association experienced good fabric filter operation when burning up to 10 percent TDF. However, when the facility tested TDF levels up to 65 percent, operation of the fabric filter was of primary concern. The ash from the rubber was significantly more difficult to cleanoff the bags than the coal ash. The resultant ash build up on the bags caused an increased pressure drop across the system from 3" to 6". Personnel operated the cleaning cycle continuously, and operated both reverse air fans for the duration of the test, which improved the situation.17... 

B) The rating of filters shall be governed by the test data supplied by the manufacturer of the filter. A pressure gage shall be installed to show the pressure drop across the filters. This gage shall be marked to show the pressure drop at which the filters require cleaning or replacement. Filters shall be replaced or cleaned whenever the pressure drop across them becomes excessive or whenever the air flow through the face of the booth falls below that specified in Table D-57.7. 

The multi-pass filter test is the normally used method for evaluating filtration performance. It consists of circulating a highly contaminated fluid through the test filter at constant flow rate and temperature. As the filter element picks up contaminant particles, the differential pressure drop across it increases. The test is terminated at a predetermined differential pressure across the filter, and three basic performance characteristics are evaluated separation efficiency (against particle size), contaminant holding capacity, and clean-assembly flow or pressure drop performance. 

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