Electrofibrous prefilters for use in nuclear ventilation systems

Conference · Thu Feb 19 04:00:00 EST 1981

OSTI ID:6367795

Bergman, W; Kuhl, W D; Russell, W L; Taylor, R D; Hebard, H D; Biermann, A H; Alvares, N J; Beason, D G; Lum, B Y

We have established a comprehensive program for the US Department of Energy to develop electrofibrous prefilters to extend the life of High Efficiency Particulate Air (HEPA) filters that are used in the nuclear industry. We have selected the electrofibrous filter because, compared to the mechanical fibrous filter, it has a higher efficiency and longer lifetime. Two different electrofibrous filters have been developed for use in nuclear ventilation systems. One prototype is a stationary prefilter while the other is a rolling prefilter. Both prefilters use the same basic filtering technique in which a fibrous filter medium is sandwiched between a high voltage electrode and a ground electrode, both electrodes having a sufficient open area to offer minimum air resistance. The applied voltage on the electrodes generates an electric field that polarizes the filter fibers, which then attract suspended particles via electrostatic forces. The filter media and electrodes have been pleated to provide a sufficiently long particle residence time. The special requirement of protecting the HEPA filter from a high concentration of smoke aerosols during fire conditions led to the development of the rolling, electrofibrous prefilter. We established the feasibility of this concept in a series of tests using commercially available rolling prefilters that were modified for removing smoke aerosols. Although the rolling prefilter concept is not a cost effective measure for the sole purpose of protecting HEPA filters from smoke aerosols, it became cost effective when used primarily for protecting the HEPA filters from normal production aerosols. The same piece of equipment is then used for both normal operating conditions as well as emergency fire conditions. Several prototype electrofibrous rolling prefilters were designed, built and evaluated. The filter evaluations were conducted using NaCl and DOP aerosols as well as smoke aerosols.

• Research Organization: California Univ., Livermore (USA). Lawrence Livermore National Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6367795
• Report Number(s): UCRL-84454; CONF-801038-22; ON: DE81023656
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420202 -- Engineering-- Protective Structures & Equipment
500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AEROSOLS
AIR CLEANING SYSTEMS
AIR FILTERS
COLLOIDS
DESIGN
DISPERSIONS
EFFICIENCY
ENGINEERED SAFETY SYSTEMS
EQUIPMENT
FEASIBILITY STUDIES
FILTERS
FILTRATION
POLLUTION CONTROL EQUIPMENT
REMOVAL
RESIDUES
SEPARATION PROCESSES
SMOKES
SOLS