Grantee Research Project Results
Continuous Micro-Sorting of Complex Waste Plastics Particle Mixtures Via Liquid-Fluidized Bed Classification (LFBC) for Waste Minimization and Recycling
EPA Grant Number: R826731Title: Continuous Micro-Sorting of Complex Waste Plastics Particle Mixtures Via Liquid-Fluidized Bed Classification (LFBC) for Waste Minimization and Recycling
Investigators: Calo, Joseph M.
Institution: Brown University
EPA Project Officer: Aja, Hayley
Project Period: February 1, 1999 through March 31, 2002 (Extended to August 31, 2003)
Project Amount: $265,000
RFA: Technology for a Sustainable Environment (1999) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , Sustainable and Healthy Communities
Description:
A fundamental investigation is proposed to provide a technical basis for the development of a novel, liquid-fluidized bed classification (LFBC) technology for the continuous separation of complex waste plastic mixtures for in-process recycling and waste minimization. Although a number of processes have been developed or proposed for the separation of waste plastics from manufacturing operations, none are completely satisfactory in terms of economics and performance. LFBC has a number of distinct advantages over most of these processes: (1) It can be used to separate a number of plastic particle types simultaneously in the same device. All other density-based techniques like flotation, centrifugation, air classification, hydroclones, etc., can only separate "lights" from "heavies" (i.e., two fractions), at best. (2) Only unmodified water is required for both "heavier-than-water" plastics ("upflow fluidization) and "lighter-than-water" plastics ("downflow" fluidization). Therefore, no density-modification of the fluidizing medium is necessary, which obviates the need for separation and recovery of modifying agents. Only water is needed to effect the separation of all plastic types; and water is already in ample use in chopping, grinding, and washing operations of plastic particles. (3) Due to the inherent physicochemical property differences between different plastic types, selective particle size/density modification can be performed in conjunction with LFBC to enhance separations, and/or to perform separations between different particle types with similar densities which are not possible using other conventional density-based separation processes. Finally, LFBC is completely compatible with most other separation/identification methods, such that it can be used in conjunction with other technology to improve the overall process economics.
Approach:
An experimental research program is presented which has been formulated to address the key technical issues that must be understood/solved in order to optimize the performance of LFBC systems and allow for their development. This involves fundamental hydrodynamic studies, including measurements of dispersion coefficients and separation performance as a function of such critical parameters as particle size, aspect ratio, and column loading, which are not available in the literature for irregularly shaped particles. The experimental focus of the proposed work is a pilot-scale column will be constructed to obtain the requisite data using in-situ image analysis techniques. The column will also be fitted with the capability to program cyclic step changes in the temperature of the fluidizing water to cause preferential modification of the size/density of selected plastic particles by type to improve separation. These data will be used to develop a predictive numerical model of system performance for particular applications of interest.
Expected Results:
The resultant data and the model will provide the basis for the design and detailed economic analysis of these systems for commercialization. An industrial partner is already identified. In addition, the Center for Environmental Industry and Technology of the USEPA, Region I (J. Cabot, Director), has indicated an interest in working with us to promote this promising technology commercially.
Estimated Improvement in Risk Management:
Successful completion of this project will provide the basis for a new, low-cost, environmentally benign technology for waste minimization.
Publications and Presentations:
Publications have been submitted on this project: View all 1 publications for this projectJournal Articles:
Journal Articles have been submitted on this project: View all 1 journal articles for this projectSupplemental Keywords:
pollution prevention; waste reduction/minimization; polymer and fiber industries; environmental engineering,, Sustainable Industry/Business, RFA, Scientific Discipline, Industry Sectors, Technology for Sustainable Environment, Manufacturing - NAIC 31-33, Chemical Engineering, Sustainable Environment, Environmental Chemistry, cleaner production/pollution prevention, liquid-fluidized bed classification, waste minimization, pollution prevention, environmentally conscious manufacturing, polymer design, waste plastic particle mixtures, cleaner production, green process systems, micro-sorting, waste reduction, in process recycling, industrial innovations, innovative technology, engineeringProgress and Final Reports:
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.