PROCESS ECONOMICS PROGRAM SRI INTERNATIONAL Abstract Process Economics Program Report No. 199 PLASTICS RECLAMATION AND RECYCLING Menlo Park, California 94025 (January 1992) In the rapidly growing business of plastics recycling, profit opportunities vary with the type of plastics. Polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PEI) are now being recycled In large volumes. PET bottles are widely used for beverages (more than 710 million lb were used in 1990 in the United States alone). Some states encourage their collection with a bottle deposit. We estimate that PET bottles can be ground, washed and separated from PE base cups and aluminum, dried and pelletized in a 50 million lb&r plant for about 2Oc/lb less than the price of virgin PET pellets. However, less expensive plastics are more difficult to recycle economically. PE milk bottles or PS foam food-service containers can be converted to flakes or pellets, but at current prices, the return on investment is less than 25%. The cost of the used plastic received at the processor s plant is a large part of the processor s total cost. Until better automatic machines are developed, the cost of manually removing extraneous matter is also significant. Recycled plastics have nearly all the desirable properties of virgin plastics. They can be blended with virgin plastics or used in a composite structure, sandwiched between layers of virgin plastic. Commingled plastics that are not separated can be processed into mixed plastics products for a small but growing market. Additives and compatibilizers improve the product properties, but contribute significantly to the cost. The plastics recycling business, which saves energy, recovers valuable materials for reuse, and spares overflowing landfills some of their ever-increasing load, includes three pans: First, the collection, sorting, and transportation to a processing center; second, the processing itself; and finally, the development of markets for recycled plastics. Slow growth in the first area is limiting recycling overall. However, new equipment and techniques - some adapted from other industries - are being developed rapidly for processing used plastics. This report reviews the state of the an In all three segments of this rapidly changing field. It focuses on the technology and economics of processing - the grinding, cleaning, drying, and reshaping of plastics Into a reusable form. Recycling equlpment and techniques are critically reviewed and compared. Because polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (Pt3) are recycled in the largest volume, they are evaluated In the greatest detail. Designed to help companies assess the impact of recent developments on their own operations, this report will also be of use to companies that are considering plastics recycling, as well as companies already engaged in various segments of the plastics business. PEP 88 RHS
Report No. 199 PLASTICS RECLAMATION AND RECYCLING by ROBERT H. SCHWAAR January 1992 A private report by the PROCESS ECONOMICS PROGRAM Menlo Park, California 94025
For detailed marketing data and Information, the reader is referred to one of the SRI programs specializing in marketing research. The CHEMCAL ECONOMICS HANDBOOK Program covers most major chemicals and chemical products produced in the United States and the WORLD PE7ROCHfM/CAlS Program covers major hydrocarbons and their derivatives on a worldwide basis. In addition, the SRI D/RECTORY OF CHEMlCAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States, Western Europe, Canada, and East Asia. ii
GLOSSARY.............................................................. xiii 1 INTRODUCTION...................................................... l-l 2 SUMMARY... 2-l COLLECTION... 2-l PLASTICS FOR RECYCLING... 2-l RECYCLING TECHNIQUES... 2-2. Polyethylene Terephthalate (PET)... 2-3 Polyethylene(PE)... 2-3 Polystyrene (PS)... 2-4 ECONOMICS... 2-4 3 INCENTIVES FOR PLASTICS RECYCLING... 3-l THE LANDFILL PROBLEM... 3-l ALTERNATIVES TO RECYCLING... 3-2 Source Reduction..... 3-2 Incineration for Energy... 3-2 Degradable Plastics... 3-2 STEPS IN PLASTICS RECYCLING... 3-3 Sources of Post-Consumer Plastics... 3-3 Collection and Preprocessing... 3-4 Economical Processing Technology... 3-4 INDUSTRIAL SCRAP AND POST-CONSUMER WASTE PLASTICS... 3-5 MARKETS FOR RECYCLED PLASTICS... 3-5 LEGISLATlVE INCENTIVES... 3-8 DEMAND-SIDE ECONOMICS... 3-7 THE FUTURE OF PLASTICS RECYCLING... 3-7 4 INDUSTRY STATUS.................................................... 4-l - Ill -
CONTENTS (Continued) 5 PET BOTTLE RECYCLING.............................................. 5-1 SEPARATION AFTER GRANULATION... Review of Individual Process Steps... Manual Sorting Before Processing... PVC Bottle Removal... Separation by Color... Granulation... Label Separation..... Granule Washing... Cryogenic Grinding/Cleaning... Separation of HDPE... Use of Solvents for & Contaminant Removal... Gross Contaminants..... Microcontaminants..... Granule Drying... Aluminum Removal... Final Drying... Extrusion... Additives... Crystallization... Integrated Systems for Separation After Granulation... John Brown... M.A. lndustries... Center for Plastics Recycling Research... AKW Apparate und Verfahren GmbH... Goodyear... St. Jude Polymer... Sepco Recycling System... A Typical PET Bottle Recycling Plant... Process Description (Separation after Granulation)... Process Discussion... Cost Estimate... investment... Processing costs... Discussion... 5-2 5-2 5-2 5-3 5-4 5-5 5-5 S-6 5-6 5-6 5-7 5-7 5-7 5-8 5-9 5-9 5-9 5-9 5-10 5-10 5-12 5-12 6-12 5-14 5-15 5-15 5-10 5-16 5-16 5-18 5-18 5-19 5-19 -h/-
CONTENTS (Continued) 5 PET BOTTLE RECYCLING (Concluded) SEPARATION BEFORE GRANULATION... 5-22 Process Review... 5-22 Recycled Polymers... 5-22 Automated Recycling Corporation... 5-24 Pure-Tech... 5-24 Plastic Recycling, inc.... 5-24 Reko BV... 5-25 Handling of Damaged Bottles... 5-25 Process Variations... 5-25 A Typical PET Bottle Recycling Plant... 5-28 Process Description (Separation Before Granulation)... 5-28 Process Discussion... 5-28 Cost Estimate... 5-28 Investment..... 5-28 Processing Costs... 5-28 Discussion... 5-30 OTHER CONSIDERATIONS... 5-31 Changes in the Polymer During Processing... 5-31 increase in PET Molecular Weight.... 5-31 Bottle Design Modifications to improve Recyclability... 5-32 Reformulation or Elimination of Adhesives... 5-32 HDPE Labels... 5-32 PET Caps... 5-33 PET Base Cups... 5-33 One-Piece Bottles... 5-33 Discussion..... 5-33 Developments that may Complicate PET Bottle Recycling... 5-33 Coating Bottles with Poly(Vinylidene Chloride)... 5-34 Returnable Bottles... 5-34 Other Polyesters... 5-34 Tertiary Recycling (PET Depolymerization)... 5-35 Markets for Recycled PET... 5-37 Competition between Recycled PET and Virgin PET... 5-37 Collection, Transportation, and Sorting... 5-38 Other Costs of Recycling PET... 5-38 -v-
CONTENTS (Continued) 6 POLYETHYLENE RECYCLING... 6-l GRADES OF POLYETHYLENE... 6-2 RECYCLING PROCESS STEPS... 6-2 Basic Recycling Process... 8-2 Size Reduction... 6-4 Separation of Other Plastics... 6-4 Separation by Color... 6-4 Washing... 6-5 Label Design to Facilitate Recycling... 6-5 Separation of Contaminants... 6-6 Water Removal...:... 6-6 Screw Dewatering..... 8-6 Screen DewaterIng... 6-6 Centrifugal Dewatering... 6-6 Thermal Drying... 6-7 Conversion of Cleaned Polymer to Marketable Product... 6-7 Extruders... 6-7 Agglomerators... 6-8 Pellet Mills... 8-9 Product Blending... 6-9 Materials of Construction... 6-9 INTEGRATED SYSTEMS... 6-9 Weiss GmbH... 6-9 Herbold Granulators USA... 6-10 M.A. lndustries... 6-11 RECYCLING HDPE MILK BOTTLES... 6-l 1 Process Description... 6-11 Process Discussion... 8-14 Cost EstImate... 8-15 Investment... 6-15 Processing Costs... 8-15 Discussion... 6-15 - vi -
CONTENTS (Continued) 6 POLYETHYLENE RECYCLING (Concluded) RECYCLING POST-CONSUMER LDPE FILM... 6-l 8 Process Description... 6-18 Process Discussion... 6-21 Cost Estimate... 6-21 investment... 8-21 Processing Costs... 6-21 Discussion... 6-23 7 POLYSTYRENE FOAM RECYCLING... 7-l PROCESSING PS FOAM FROM DRY RESTAURANT TRASH... 7-3 Conversion of Slurry to Dry Product... 7-4 Screen Dewatering... 7-5 Centrifugal Dewatering... 7-5 Dewatering Screw Press..... 7-5 Thermal Drying... 7-5 Small-Scale Processing of Used Food-Service PS Foam... 7-5 PROCESSING CLEAN POLYSTYRENE FOAM... 7-8 PROCESS DESCRIPTION... 7-7 PROCESS DISCUSSION... 7-l 0 COST ESTIMATE... 7-l 1 Investment... 7-11 Processing Costs... 7-11 Discussion... 7-11 SOLUBLE POLYSTYRENE - ANOTHER APPROACH... 7-l 3 8 RECYCLING OF OTHER PLASTICS... 8-l PVC RECYCLING... 8-l Recycling Hierarchy for PVC... 8-l Separation of PVC from other Plastics... 8-2 Asoma lnstruments... 8-3 Govoni SpA... 8-3 National Recoveries Technologies (NRT)... 8-3 Hoover Universal... 8-3 Contaminant Removal... 8-3 Markets for Recycled PVC Products... 8-3 -vii -
CONTENTS (Concluded) RECYCLING OF OTHER PLASTICS (Concluded) POLYPROPYLENE... 8-4 POLYURETHANE... 8-4 ENGINEERING THERMOPLASTICS... 8-4 REINFORCED THERMOPLASTICS... 8-5 MULTILAYER STRUCTURES... 8-5 THERMOSETTING RESINS... 8-5 DEGRADABLE PLASTICS... 8-5 MIXED PLASTICS RECYCLING... 9-l SOURCES OF RAW MATERIAL FOR RECYCLED MIXED PLASTIC... 9-l PROCESSING COMMINGLED PLASTICS WASTE INTO USEFUL PRODUCTS... 9-4 INClNERATION OF MIXED PLASTICS... 9-5 PROCESS DESCRIPTION... 9-5 PROCESS DISCUSSION... 9-8 COST ESTIMATE... 9-8 APPENDIX A: PATENT SUMMARY TABLES... APPENDIX B: CITED REFERENCES... APPENDIX C: PATENT REFERENCES BY COMPANY... A-l B-l C-l - viii -
ILLUSTRATIONS 5.1 SEPARATION AFTER GRANULATION AKW PROCESS FOR PET RECYCLING..,... 5-13 5.2 SEPARATION AFTER GRANULATION PROCESS FLOW FOR TYPICAL PET BOTTLE RECYCLING PLANT....... 5-17 5.3 SEPARATION BEFORE GRANULATION PROCESS FLOW FOR TYPICAL PET BOTTLE RECYCLING PLANT....... 5-27 6.1 HDPE MILK BOTTLE RECYCLING PROCESS FLOW DIAGRAM....................................... 6-12 6.2 LDPE FILM RECYCLING PROCESS FLOW DIAGRAM....................................... 6-19 7.1 POLYSTYRENE FOAM RECYCLING PROCESS FLOW DIAGRAM....................................... 7-8 9.1 CONFIGURATION OF A TYPICAL MATERIALS RECYCLING FAClLlTY (MRF)...................................... 9-3 9.2 MIXED PLASTICS RECYCLING PROCESS FLOW DIAGRAM....................................... 9-7 - ix -
TABLES 2.1 SUMMARY OF ECONOMIC EVALUATIONS........................... 2-5 4.1 PLASTICS RECYCLING IN THE UNITED STATES...................... 4-l 5.1 WEIGHTS OF TYPICAL PET BOTTLES.............................., 5-2 5.2 SEPARATION AFTER GRANULATION INTEGRATED PET RECYCLING PROCESSES......................... 5-11 5.3 SEPARATION AFTER GRANULATION ECONOMICS OF RECYCLING PET BOTTLES........................ 5-20 5.4 SEPARATION BEFORE GRANULATlON INTEGRATED PET RECYCLING PROCESSES.............,.........,. 5-23 5.5 SEPARATION BEFORE GRANULATION ECONOMICS OF RECYCLING PET BOTTLES........................ 5-29 6.1 MELT FLOW RANGES OF VARIOUS GRADES OF POLYETHYLENE,....., 6-3 6.2 HDPE MILK BOTTLE RECYCLING MAJOR EQUIPMENT............................................. 6-13 6.3 ECONOMICS OF HDPE MILK BOTTLE RECYCLING................... 6-16 8.4 LDPE FILM RECYCLING MAJOR EQUIPMENT... 6-20 6.5 ECONOMICS OF LDPE FILM RECYCLING........................... 6-22 7.1 7.2 7.3 9.1 U.S. PRODUCERS OF POLYSMRENE..,........................... POLYSTYRENE FOAM RECYCLING MAJOR EQUIPMENT............................................. ECONOMICS OF POLYSTYRENE FOAM RECYCLING.................. ECONOMICS OF MIXED PLASTICS RECYCLING...................... 7-2 7-9 7-12 9-9 A.1 PET RECYCLING PATENT SUMMARY.............................................. A-4 A.2 DEPOLYMERIZATION OF PET PATENT SUMMARY.............................................. A-9 A.3 A.4 RECYCLING OF PLASTICS OTHER THAN PET PATENT SUMMARY.............................................. MECHANICAL CRUSHING AND SORTING DEVICES PATENT SUMMARY.............................................. A-13 A-19 - xi -