AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Effect of Relative Humidity and Particle Material on Filter Loading
QISHENG OU, David Y. H. Pui, Allan Ouyang, University of Minnesota
Abstract Number: 449 Working Group: Control Technology
Abstract The filter dust holding capacity depends on the properties of the particles that are trapped in/on the filter as well as the environmental conditions where the filter is in operation. In the standard test method, such as the ISO 5011 and ASHRAE 52.2, dry coarse dust particles are typically used, and the relative humidity is only regulated at a wide range. However, depending on the application and service location, many filters are used in an environment where particles exhibit much smaller size distribution in sub-micrometer range and various chemical compositions. In order to more precisely predict the lifetime of the filters utilized in the practical conditions, these filters need to be tested with particles with similar size, morphological and chemical properties and under similar humidity condition. In this study, filter loading behaviors were tested with several types of particles in both super-micrometer and sub-micrometer size range, under a wide range of relative humidity condition. Factors that affect the filter loading behaviors were investigated.
Two different methods were used to generate submicrometer particles, which may mimic fine mode particles from different emission sources. A home-made atomizer followed by diffusion drier was used to generate nearly spherical particles. A propane flame was used to generate fractal-like agglomerates. ISO 12103-1 A2 dust was dispersed to present the coarse mode aerosol in the atmosphere, which is the standard test aerosol specified in ISO 5011:2014. These laboratory generated particles were loaded on a 57-mm diameter flat filter media. The relative humidity in the system was controlled and monitored during the experiments. A wide range of relative humidity from 10% to 90% was tested to investigate its effect on loading together with particle properties. The pressure drop of the tested filter media was monitored during the loading. The penetration evolution during the loading were measured by Scanning Mobility Particle Sizer (SMPS) for fine particles and Aerodynamic Particle Sizer (APS) for coarse particles. More results with different filter media, particle types and size ranges will be presented in the talk.