Study of the effect of humidity, particle hygroscopicity and size on the mass loading capacity of HEPA filters
The effect of humidity, particle hygroscopicity and size on the mass loading capacity of glass fiber HEPA filters has been studied. At humidifies above the deliquescent point, the pressure drop across the HEPA filter increased non-linearly with the areal loading density (mass collected/filtration area) of NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or non-hygroscopic particle mass loadings. The specific cake resistance, K{sub 2}, has been computed for different test conditions and used as a measure of the mass loading capacity. K. was found to decrease with increasing humidity for the non-hygroscopic aluminum oxide particles and the hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K{sub 2} for lognormally distributed aerosols (parameters obtained from impactor data) is derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the non-hygroscopic aluminum oxide the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor.
- Research Organization:
- Westinghouse Savannah River Co., Aiken, SC (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035
- OSTI ID:
- 7270999
- Report Number(s):
- WSRC-MS-92-114; CONF-921110-23; ON: DE92019679
- Resource Relation:
- Conference: Winter annual meeting of the American Society of Mechanical Engineers, Anaheim, CA (United States), 8-13 Nov 1992; Other Information: Thesis (M.S.). Thesis submitted by A. Gupta to University of Cincinnati
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters
Experimental relationship between the specific resistance of a HEPA (High Efficiency Particulate Air) filter and particle diameters of different aerosol materials
Related Subjects
AEROSOLS
FILTRATION
FILTERS
PERFORMANCE
PRESSURE DROP
ALUMINIUM OXIDES
GLASS
MOISTURE
PARTICLE SIZE
RADIOACTIVE EFFLUENTS
SODIUM CHLORIDES
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHLORIDES
CHLORINE COMPOUNDS
COLLOIDS
DISPERSIONS
HALIDES
HALOGEN COMPOUNDS
MATERIALS
OXIDES
OXYGEN COMPOUNDS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SEPARATION PROCESSES
SIZE
SODIUM COMPOUNDS
SOLS
WASTES
540130* - Environment
Atmospheric- Radioactive Materials Monitoring & Transport- (1990-)