Stress-controlled particulate filters

San Diego State University Foundation, San Diego CA

Investigators

Abstract

STRESS-CONTROLLED PARTICULATE FILTERS CMS-0511002 PI: Julio R.. Valdes This project centers on the development of a novel filtration technology, in which the particulate filter matrix is controlled externally to selectively block or allow the passage of preferred particle sizes by size exclusion. The system works as follows. Typical mineral filter matrix particles (e.g., sand grains) are replaced by low-stiffness grains (e.g., rubber chips). The application of external stresses causes increased grain compression, which leads to pore-throat size reductions and enhanced particle entrapment. Conversely, relaxing the applied stresses produces system expansion, enlargement of pore-throats, and increased particle flushing (i.e., filter unclogging/cleaning). It is anticipated that the technology will dramatically reduce problems associated with filter clogging and unclogging, namely inefficiencies and high costs related to preventing and promoting such processes. The main objectives of the research program include (1) identifying relationships among relevant particle-scale filtration processes placing emphasis on scaling parameters, and (2) engineering particulate mixtures for optimized stiffness and filtration/flushing control through the monitoring of filtration operations in the laboratory. The research will serve as a means to obtain pilot filter performance data and to develop an optimized plan for future testing. The goals translate to broader impacts through the development of controllable particulate filters for increased efficiency in a variety of operations, including air and water treatment, soil retention, grain sorting, and sustainable filtration technologies in isolated environments such as inter-oceanic vessels (e.g., ballast filtration) and spacecraft. The educational component is the development of didactic web-based and demonstrative tools that will be used in courses pertaining to Project Lead the Way at San Diego State University. This nationally established program is aimed to increase the number and quality of engineering graduates via pre-college courses developed for instructing middle and high school teachers in engineering education.